摘要:

J O U R N A L OF THE CHEMlICAL SOCIETY. Qammitiee af @nbiicntion : Chairma~a N. V. SIDGWICK M.A. Sc.D. F.R.S. H. B. BAKER C.B.E. D.Sc. F.E.S. E. C. C. BALY C.B.E. F.R.S. H. BASSETT D.Sc. Ph.D. 0. L. BRADY D.Sc. A. W. CROSSLEY C.M.G. C.E.E., F. G. DONNAN C.B.E. &LA. F.:R.S. H. W. DUDLEY O.B.E. M.Sc. Ph.D. U. R. EVANS M.A. J. J. Fox O.B.E. DSc. C. S. GIBSON O.B.E. &LA. A. J. GEEENAWAY F. I.C. 1. 11. HEILBRON D.S.O. D.Sc. F.R.S. T. A. HENRY D.Sc. I C. I<. INGOLD D.Sc. F.R.S. H. MCCOMBIE D.S.O. M.C. D.Sc. J. 'I. 0. MASSON M.B.E. D.Sc. W. H. XILLS Sc.D. F.R.S. T. S. MOORE &LA. E.,Sc. G. T. MORQAN O.B.E. D.Sc. F.R.S. J. R. PARTINGTOK M.B.E. D.Sc. J. C. PHILIP O.R.E. D.Sc. F.R.S. R. H. P ~ c ~ i i n n D.Sc. F.R.S. T. S. PRICE O.K.E.n.Sc. F.R.S. F. L. PYMAN D.Sc. F.R.S. J. F. THORPE C.B.E. D.Sc. F.R.S. w. P. TYYSSE n.sc. F.R.S. 6Ebitox : CLAREFCE SMITE D.Sc. JIARGAILET LE PLA R.&. 1925 Vol. CXXVII. Part I. pp. 1-1491. ~ - _ _ - _ _ _ -IIONDOh': GURNEY & JACESON 33 PATERNOSTER ROW E.C. 4. 1935 PRINTED IN GREAT BRITAIN BY RICHARD CLAY & SONS LIMITED, BUNGAY SUFFOLK C O N T E N T S PAPERS COMlklUNICATED TO THE CHEMICAL SOCIETY. PAQB 1.-The So-called Poisoning of Oxidking Catalysts. By CULES MOUEEU and CHARLES DUFEAISSE . . 1 11.-A Fractionating Column with Moving Parfs. By JAMES ECRRFL~LEY MY= and W m JACOB JONES . . 4 111.-The Absorption Spectra of Various Aldehydes and Ketones and some of their Derived Compounds. By JOHN EDWABD Poav~s . . 9 1V.-The Ignition of Gases.Part V. Ignition by Induct-ance Sparks. Mixtures of the Paraffins with Air. By RICHABD VEBNON WHEELER . . 14 V.-The Partial Formaldehyde Vapour Pressures of Aqueous Solutions of Formaldehyde. Part I. By ETHELBERT Wrr.rallm BLAIR and WIL~UD LEDBURY . . 26 VI.-The Detection of Methylamine in Presence of Excess VI1.-Nitro-derivatives of 0-Cresol. By GEORGE PHILIP GIBSON . . 42 VIII.-LimitR for the Propagation of Flame in Inflam-mable Gas-& Mixtures. Part 11. Mixtures of More than One Gw and Air. By ALBEBT GEEVILLE WHITE . 48 IX.-Solubility of Bi-bivalent Salts in Solutions Containing a Common Ion. By OSWALD JAMES WALKER . . 61 X.-Organic Compounds of Arsenic. Part 11. Derivatives of the Arsenic Analogue of Carbazole. By JOHN ALFRED AESCHLJBIA" NORMAN DEBWSTER LEES NIAL PATRICK MCCLELAND a d GEORGE NOEMAN NICELIN .. 66 XI.-Synthesis of Arachidic Acid and some Long-chain Compounds. By NEIL K. ADAM and JOSEPE W. W. DYEB . . 70 XI1.-The Adsorption of Catalytically Poisonous Metals by Plafinum. Part I. The Adsorption of Lead and Part IV. Spectra of Explmions of Gases containing Hydrogen, Carbon Nitrogen and Oxygen. By WILLI~M EDWABD GARNEB and SIDNEY WALTER SATJNDERS . . . 77 of Ammonia. By P. A. VALTON . . # Mercury. By EDWARD BRADFORD MAXTED . . 73 XII1.-The Explosion of Acetylene and Nitrogen iv CONTENTS. XIV.-Remtions of Displacement in the Tropic Acid Group. Part I. By ALEX. MCKENZIE and ROBERT CAMPBELL STRATHERN . XV.-Preparation of Quaternary Hydrocarbons. By EDWARD RUSSELL T~OTMAN .XV1.-Transformation of Mandelonitrile to Mandeloiso-nitrile. By CHARLES EDMUND WOOD and HAROLD SAMUELILLEY By FREDERICK GEORGE SOPER Part 11. By FORSYTH JAMES WILSON and ARCHIBALD BARCLAY CRAWFORD Studies in the Composi-tion of Coal. By FREDERICK VINCENT TIDESWELL and RICHARD VERNON WHEELER . XX.-The Oxidation of Banded Bituminous Coal at Low Temperatures. Studies in the Composition of Coal. By WILFRJD FRANCIS and RICHARD VERNON WHEELER . Studies in the Com-position of Coal. By FREDERICK VINCENT TIDESWEI~L and RICHARD VERNON WHEELER . XXI1.-The Chemisttry of Lignin. Part 11. A Comparison of Lignins Derived from Various Woods. By WALTER JAMES POWELL and HENRY WHITTAKER . XXII1.-A Redetermination of the Atomic Weight of Bromine.The Inseparability of the Isotopes by Fractional Crystallisation. By PERCY LUCOCK ROBIN-SON and HENRY VINCENT AIRD BRISCOE XX1V.-The Use of Fused Borax in the Determination of the Atomic Weight of Boron. By HENRY VINCENT AIRD BRISCOE PERCY LUCOCK ROBINSON and GEORGE EDWARD STEPHENSON . XXV.-The Sulphur Compounds of Kimmeridge ShaIe Oil. Part I. By FREDERICK CHALLENGER JAMES RICHARD ASHWOR~ JINKS and JOHN HASLAM XXV1.-A Synthesis of Pyrylium Salts of Anthocyanidin Type. Part V. The Synthesis of Cyanidin Chloride and of Delphinidin Chloride. By DAVID DOIG PRATT and ROBERT ROBINSON . XXVII.-Synthesis of certain Higher Aliphatic Compounds. Part I. A Synthesis of Lactarinic Acid and of Oleic Acid. By GERTRUDE MAUD ROBINSON and ROBERT ROBINSON XVI1.-The Hydrolysis of Bcylchloroamines in Water.XVII1.-The Action of Amines on Semicarbazones. X1X.-Banded Bituminous Coal. XX1.-On h a i n and its Oxidation. . PAGE 82 58 95 98 103 110 112 125 132 138 150 162 166 17 CI0"TS. v PAQB XXVII1.-A Synthesis of Myricetin and of a Galangin Monomethyl Ether Occurring in Galanga Root. By JAN KALFF and ROBERT ROBINSON XX1X.-Researches on Residual Affinity and Co-ordination. Part XXIII. Interactions of Trimethylstibine and Platinic and Palladous Chlorides. By GILBERT T. MORGAN and VICTOR EMMANUEL YARSLEY . SXX.-cry-Dialdehydopropane-pp-dicarboxylic Acid and ay-Dialdehydopropanene/3-carboxylic Acid. By WILLIAM HEM~Y PERKIN jun. and HERBERT SHEPPARD PINK . XXX1.-New Synthesis of the Meconines.By GEORGE ALFRED EDWARDS WILLIAM HENRY PERKIN jun. and FRANCIS WILBERT STOYLE XXXI1.-Method of Measuring the Reduction Potentials of Quinhydrones. By EIXAR BIILMANN A. LANGSETH JENSEN and KAI 0. PEDERSEN XXXII1.-Hydrolysis of the d-Glucosides of d- and I-Borneo1 with Emulsin. By STOTHERD MITCHELL . XXXIV.-Some Co-ordinated Compounds of the Alkali Metals. By NEVIL VINCENT SIDCWICK and SYDNEY GLENN PRESTON PLANT . XXXV.-Reduction of the Carbocyanines. By FRANCES MLRY HAMER . XXXV1.-Fission of the Pyridine Nucleus during Reduction. Part 11. The Preparation of Glutardialdoxime. By BRIAN DUNCAN SHAW . XXXVI1.-The Action of Bromine on Sodium and Silver hides. By DOUGLAS ARTHUR SPENCER . XXXVII1.-The Constitution of Disulphoxides. Part 11. By CECIL JAMES MILLER and SAMUEL SMILES XX X IX .-Resolution of C hlorosulp h oace t ic Acid into its Optically Active Components.By HILMAR JOHANNES BACKER and WILHELM GERARD BURGERS . XL.-The Rotatory Dispersive Power of Organic Compounds. Part XIV. Simple Dispersion in 1 -MethylcycZohexyl-idene-4-acetic Acid. By EVAX MATTHEW RICHARDS and SL1.-The Electrical Explosion of Tungsten Wires. By HENRY VINCENT AIRD BRISCOE PERCY LUCOCK ROBIN-SON and GEORGE EDWARD STEPRENSON XLI1.-Physostigmine (Eserine). Part 111. By EDGAR STEDMAN and GEORGE BARGER . . THOMAS MARTIN LOWRY . . 181 184 191 195 199 208 209 211 215 216 224 233 238 240 24 vi COHTEH"8. XLII1.-The Action of Light on the Ferrous Ferric Iodine Iodide Equilibrium. By ERIC KEIGHTLEY RIDEAL and EDWARD GARDNER WILLIAMS .XL1V.-The Condensation of Phenylethylamine with s-Di-chlorodimethyl Ether. By WALLACE FRANK SHORT . XLV.-New Halogen Derivatives of Camphor. Part VI. p-Bromocamphor-a-sulphonic Acid. Part VII. The Constitution of the Reychler Series of Camphor-mlphonic Acids. Experiments on Chlorosulphoxides. By HENRY BTZRGESS and THOMAS M~RTIN LOWRY. XLVI.-Conversion of Amino-acids into Tertiary Amino-alcohols. By ALEX. MCKENZIE and GEORGE OGILVIE WILLS . XLVI1.-The Action of Caustic Alkali on a-Bromo-a-ethyl-butyrylcarbamide. By GEOME NEWBEBY XLVIII.-The Direct Combination of Ethylenic Hydro-carbons with Hydrogen Sulphites. By ISRAEL KOLKER and ARTHUR LAPWORTH . . XL1X.-A Method of Measuring the Dielectric Constants of Liquids.By LEONABD ALFRED SAYCE and HENRY VINCENT AIRD BRISCOE . . L.-Studies in Electro-endosmosis. Part III. By &ED FAIRBROTHER and HAROLD MASTIN . L1.-A Comparison between the Homogeneous Thermal Decomposition of Nitrous Oxide and its Heterogeneous Catalytic Decomposition on the Surface of Platinum. By CYRIL NORMAN HINSHELWOOD and WES Ross LI1.-The Hydrolytic Decomposition of Phosphorus Tri-chloride. By ALEC DUNCAN MITCHELL . LIE-The Heats of Solution and of Decomposition of Chlorine Dioxide. By HENRY BOOTH and EDMUXD JOHN BOWEN . LIV.4yoscopic Measurements with Nitrobenzene. Part In. Equilibrium in Nitrobenzene Solution. By FREDERICB STANLEY BROWN . LV.-Constitutional Studies in the Monocarboxylic Acids Derived from Sugars. Part In.The Isomeric Tetra-methyl Galactonolactones and Trimethyl Arabono-lactones. By JOHN PRYDE EDM-UND LANGLEY HIRST, and ROBERT WILLIAM HUMPRREYS . LV1.-The Constitution of the Normal Monosaccharides. Part 11. Arabinose. By EDWD LANGLEY HIRST and GEORQE JAMES ROBERTSON . . PRICHARD . PAOB 258 269 271 283 295 307 315 322 327 336 342 345 348 35 CONTENTS. Vii PAQP LVII.-Synthesis of Derivatives of 7-habinuse. By STANLEY BAKER and WALTER NORMAN HAWORTEI . LvpII.-Phenyl Benzyl Diketone and some Derivatives. By THOMAS ~~~LKIN and ROBERT ROBINSON LIX.-The Additive Formation of Four-membered Rings. Part VI. The Addition of Azo-compounds to Ethylenes and some Transformations of the Dimethylene-1 2-di-imine Ring. By CHRISTOPEER KELK INUOLD and STANUEY Dooaus WEAVEB .LX.-The Conditions Underlying the Formation of Un-saturated and Qclic Compounds from Halogenated Open-chain Derivatives. Part VI. Products Derived from Halogenated a-Methylglutaric Acids. By CHRIS-LX1.-Investigations on the Dependence of Rotatory Power on Chemical Constitution. Part XXIV. Further Ex-periments on the Walden Inversion. By JOSEPH KENYON HENRY PHILLWS and HAROLD GEOME TnaLEY . LXII.-!I%e Relative Rates of Catalytic Hydrogenation of Different Types of Unsaturated Compounds. Part I. Aliphatic Ethylenic Derivatives. By S. V. LEBEDEV, G. G. KOBWSKY and A. 0. YAKWCHIK LXIII.-!l%e Reactions of Sodium Mono- Di- and Tri-sulphides with 1 -Chloro-2-nitro- 1 -Chloro-4-nitro- and 1 4-Dichloro-2-nitro-benzene.By HERBERT HENRY HODQSON and JAMES HENRY W ~ O N . LXIV.-Fu.rther Experiments on the Periodic Dissolution of Metals. By ERNEST SYDNEY HEDGES and Jaarrcs EC~ERSLEYMYERS . . . LXV.-The Addition of Ethyl Malonate to Anils. By EDWARD JOHNSON WAYNE and J m s BEREND COHEN LXVI.-The Chemistry of the Glutaconic Acids. Part XVIII. Three-carbon Tautomerism in the cyclopro-pane Series. Part N. By FRANK ROBERT Goss, CHRISTOPHIE~ KELK INGOLD and JOCELYN FIELD LXVII.-The Correlation of Additive Reactions with Tauto-meric Change. Part IV. The H e c t of Polar Con-ditions on Reversibility. By EDITH HILDA INQOLD LXVIII.-The Mechamism of Kolbe's Electrwynthesis. By RALPH EDWABD GIBSON . . . TOPHEB KELK INGOLD . . THOWE . . (USHERWOOD) . . 365 369 378 387 399 417 440 445 450 460 449 47 viii comms.LXIX .-The Diffusion-potential and Transport Number of Hydrochloric Acid in Concentrated Solution. By SYDNEY RAYMOND CARTER and FREDERICK MEASHAM LEA . NOTES .-Reduction of Aromatic Nitro-compounds. By RALPH WINTON WEST . Some Metallic Couples decomposing Water at the Ordinary Temperature. By ERNEST SYDNEY HEDGES and JAMES ECKERSLEY MYERS . Crystalline Cuprous Bromide. By DENNIS BROOK BRIMS The Molecular Weight of Cholesterol. By JAMES RIDDICK PARTINGTON and SIDNEY KEENLYSIDE TWEEDY . 2-Nitro-m-cresol and 2-Amino-m-cresol. By HERBERT HENRY HODGSON and HERBERT GREENSMITH BEARD . LXX.-The Influence of Acid Concentration on the Oxidation-Reduction Potential of Cuprous and Cupric Chlorides. By SYDNEY RAYMOND CARTER and FREDERICK f i s m LEA LXX1.-The Action of Light on Chlorine Dioxide.By HENRY BOOTH and EDMUND JOHN BOWEN LXXII.-The Nature of the Alternating Effect in Carbon Chains. Part I. The Directive Influence of the Nitroso-group in Aromatic Substitution. By CHRXSTOPHER KEm INGOLD . LXXII1.-The Synthesis of Glycols from Atrolactinic Acid. By ROBERT ROGER . LXX1V.-The Preparation of Pure Methyl Alcohol. By HAROLD H~RTLEY and HUBWHREY RIVAZ RAIKES . LXXV.-Studies of Equilibrium in Systems of the Type A&(SO,),-M"S0,-H,O. Part I. Aluminium Sulphate-Copper Sulphate-Water and Aluminium Sulphate-Manganous Sulphate-Water a t 30". By ROBERT M h m CAVEN and THOMAS CORLETT ETCHELL LXXVI.-Interactions of Tellurium Tetrachloride and Acetic Anhydride.By GILBERT T. MORGAN and ELARRY DTJGALD KEITH DREW . LXXVI1.-The Influence of Valency Direction on the Dissociation Constants of Dibasic Acids. By C~AUDE HYUN SPIERS and JOCELYN FIELD TEORPE . LXXVIII.-6-Chlorophenoxarsine. By EUSTACE EBENEZER TURNER and ~ T H T J R BRAXTON SHEPPARD . LXX1X.-A Determination of the Melting and Transition Points of Potassium Dichromate. By PERCY LUCOCK ROBINSON GEORGE EDWARD STEPHENSON and HENRY VLNCENT AIRD BRISCOE . . PAQE 487 494 495 496 496 498 499 510 513 51 8 524 527 531 538 544 54 CONTENTS. ix PAGE LXXX.-!I%e Reactivity of Antimony Halides with Certain Aromatic Compounds. Part II. By EXNEST VANSTONE LXXXT.-The Cryoscopic Method for Adsorption. By HENBY LORIMER RICHAILDSON and PHILIP WILFXD ROBEBTSON .. Part I. Nitration of Derivatives of p-Resorcylaldehyde. By MYSOBE GURU ~IUNIVAS BAo C~LLURAYAHA S m , and MYSORE SESHA IYENGAIZ . . T,XXI.-Syntheses of Substituted Succinic Acids con-taining Aromatic Residues. By WILSON BAKEB and LXIZlZrV.-Ring-chain Tmtomerism. Part XII. Deriv-atives of pp-Dimethyl-a-ethylglutaric Acid. By GEOR~E ARMAND ROBERT KON LAURENCE FREDEREK S m , and JOCELYN FIELD THOBPE . LXXXV.-Tautomerism of Amidines. Part V. Methyl-ation of Glyoxalines by Diazomethane. Bromination of 4(or 6)-PhenylglyoxaJine. By WILLTAM GREENWOOD FOB~PTH and FRANK LEE PYMAN LXXXVI.-!I'he Relation of Pilocarpidine to Pilocarpine. Synthesis of 1 4- and 1 5-Dimethylglyoxaline. By RICIKARD BUBTLES FRANK LEE PYMAN and JAMES ROYLANCE.. LXXXVI1.-An X-Ray Investigation of Saturated Aliphatic Ketones. By WILLIAM BRISTOW SAW and GEORGE S- . LXXXVIII.-Further X-Ray Measurements on Long-chain Compounds (n-Hydrocarbom). By ALEX. M&EB and WILLLOI BIZISTOW SAVILLE . LXXXTX.-The Rotatory Dispersive Power of Organic Com-pounds. Part XV. Borneol Camphor and Camphor-quinone. The Origin of Complex and Anomalous Rotatory Dispersion. By THOMAS MABTI-N LOWBY and JOHNOUTBAMC~~~~~ER . XC.-The Chemistry of the Three-carbon System. Part III. The a p p y Change in Unsaturated Acids. By GEORGE ABMAXD ROBERT KON and REGINALD PATELICK Iir~sl.ree~ XC1.-A Method of Determining the Presmce or Absence of Complex Salts or Ions in Dilute Aqueous Solution. By Wna,~~nr -TON PATTERSON and JOHN DUCKETT .XCII.4tudies on Starch. Part II. The Constitution of Polymerised Amylose Amylopectin and their Deriv-ativea. By ARTHUR ROBERT LING and DINSHAW RATTONJI Nmn . 0 8 0 0 T,XXXIT.-Substitution in Resorcinol Derivatives. hT'J€UB LAPWOBTE . . 550 553 556 560 567 573 581 591 599 604 616 624 62 X CONTENTS. XCIII.-Studies on Starch. Part III. The Nature and the Genesis of the Stable Dextrin and of the Maltodextrins. By ARTHUR ROBERT LINQ and DZNSHAW RATTONJI NANJI . . . . XCIV.-Studies on Sfarch. Part IV. The Nature of the Amylo-hemicellulose Constituent of Certain Starches. By ARTHUR ROBEBT LIXQ and DINSHAW RATTONJI NmJI . . . . . . XCV.-The Thermal Decomposition of Nitrogen Pentoxide. By HERBERT S. HIRST . XCVI.-Limits for the Propagation of Flame in Inflammable Gas-& Mixtures.Part III. The Effect of Temperature on the Limifs. By ALBERT GREV~LLE WHITE . . XCVIL-Styrylbenzopyrylium Salts. Part IV. y-Styryl Derivatives of 5 'I-Dihydrorrg- and 5 7-Dimethoxy-2-phenyl-4-methylbenzopyrylium Chloride. By GEORQE HUGH WALKER and ISIDOR MORRIS HEILBRON XCWIC.-Styrylbenzopyrylium Salts. Part V. Distyryl Derivatives of '7-Hydroxy-2 4-di1nethylbenzopyrylium Chloride. By Isrooa MORIU~ HEILBRON GEORGE HUGH WALKER and JOHANNES SYBMDT BUCK . . XCIX.-A Redetermination of the Atomic Weight of Boron. BY'HENRY VINCENT AIRD BMSCOE and PERCY LUCOCK ROBINSON C.-The Alternation in Molecular Volume of the Normal Monobasio Fatty Acids. By WILLIAM EDWARD GARNER and ERIC BLLITT RYDER .. . CI.-!l%e Interaction of Nitrogen Sulphide and Sulphur : Nitrogen Persulphide. By FRANCIS LAWRY USHEB . CI1.-The Interaction of Sodium Chloride and Alumina. By FRANCIS HERBERT CLEWS . . CII1.-A Synthesis of Oxyberberine. Part I. By WILLJAM HENBY €" jun. JANENDRA NATH RAY and ROBE~T ROBINSON . . C1V.-The Surface Tensions of Aqueous Solutions of Varioua Organic Compounds. By PEWAL ROWLAND EDWARDS CV.-Quantitative Reduction by Hydriodio Acid of Halogenated Malonyl Derivatives. Part IV. The Influence of Substitution in the Amide Group on the h d i v i t y of the Halogen Atom in Bromomalonamide. By RATZH WINTON WEST. . . . Part VIII. The Velocity of Formation of Certain Quaternary Ammonium Sdh. By HAMILTON MCCOMBIE HUGH MEDWYN ROBIPBTS and HAROLD ARCHIBALD SCAR-.CVI.-The Velocity of Reaction in Mixed Solvents. BOBOUGE . . . 0 0 0 PAQE 636 652 667 672 685 690 696 720 730 735 740 744 748 75 CONTENTS. CVI1.-A New Method of Flame Analysis. By OLIVER COLIGNY DE CHARWFLEUR ELLIS and HENRY ROBINSON CVII1.-The Movement of Flame in Closed Vessels. By O ~ E COLIGNY DE CHAMPFTXJR ELLIS and RICHARD ~ o T E s . - ~ - ~ ~ ~ o ~ o ~ ~ o ~ ~ ~ ~ Derivatives. By LESLIE A Qualitative Test for Weak Bases. By ROBERT ROBINSON A New Portable Apparatus for the Analysis of Illuminating and Other Gases. By H ~ H R E Y DESMOND MWRMY . C1X.-The Relationship of Thyroxin to Tryptophan. By C. STANTON HICKS . CX.-The Effect of Colloids in the Displacement of Lead and Copper from their Salts by Zinc.By LEONARD THOMAS MILLER GRAY . . CX1.-The Surface Tensions of Aqueous Phenol Solutions. Part I. Saturabd Solutions. By ARTHUR KJZNNETH GOABD and EBIC KEIGHTLXY RID- . CXI1.-The Photosensitive Pormation of Water from its Elements in the Presence of Chlorine. By RONALD GEOBGE WREYFOBD NORRISH and ERIC KEIGHTLEY RIDEAL . CXIII.-cycloTelluropentanediones Containing Aliphatic and Aromatic Substituents. By GILBERT T. MORGAN and CYR~LJA.XESA~,~,~NTAYLOR . CX1V.-The Interaction of Hydrogen and Carbon Dioxide on the Surface of Platinum. By CHARLES ROSS -CHARD and CYBIL NORMAN HINSHELWOOD . CXV.-Asymmetric Compounds of Quinquevalent Arsenic. By JOHN ALFRED AES-N CXVI.-The Chemistry of the Three-carbon System. Part IV. A Case of Retarded Mobility.By GEORGE ARMAND ROBERT KON and REGINALD PATRICK LINSTEAD CXVI1.-The Photodecomposition of Chlorine Water and of Aqueous Hypochlorous Acid Solutions. Part I. By ARTHUR JOHN ALLMAXD &aCY WALMSLEY CUNLIFFE, and ROBEBT EDWIN WITTON MADDISON CXVIII.-!lXe Composition of the Liquid and Vapour Phases of Mixtures of Glycerol and Water. By MANATHATTAI PICHU IYEB VEITKATARAMA IYER and FRANCIS LAWRY USHEB . CX1X.-The Isomerism of the Oximes. Part XXI. Action of Picryl Chloride and of 2 4-Dinitrochlorobenzene on Aldoximes. By OSUM L. BBBDY and Lorn KLEIN . VERNONWHEELEB . RANDAL RIDGWAY and ROBEBT ROBINSON. . xi PAGE 760 764 767 768 769 77 1 776 780 787 797 806 811 815 822 841 84 xii CONTENTS. CXX.-The Equilibria Underlying the Soap-boiling Pro-cesses.Pure Sodium Palmitate. By JAMES WILLIAM McBm and GUY MONTAGUE LANGDON CXX1.-The Nature of the Alternating Effect in Carbon Chains. Part II. The Directing Influence of the a-Methoxyvinyl Group in Aromatic Substitution. By CHIUSTOPHER KELK INGOLD and EDITH HILDA INGOLD . CXXII .-Br omo- derivatives of m - Hydr oxybenzaldehyde . By HEIXBERT HENRY HODCISON and HERBERT GREENSMITH BEARD . CXX1II.-The Hydrolysis of Iodine as Measured by the Iodine Electrode. By HUMPHREY DESMOND M ~ E L E ~ ~ Y . CXXIV.-The Condensation of P-Chloro- and a-Ethyl-carbonato-propionitriles with Resorcinol. By ERNEST CHAPMAN and HENRY STEPHEN CXXV.-The Labile Nature of the Halogen Atom in Organic Compounds. Past X. The Action of Hydrazine Hydrate on the Halogen Derivatives of a-Nitro-fatty Acids.By ALEXANDER KILLEN M~CBETH and DAVID T R A I L L . CXXVL-The Chemistry of Petroleum. Part I. The Occurrence of Compounds of Sulphur in the Light Distillate from the Crude Oil of Maidan-i-Naftun. By STANLEY FRANCIS BIRCH and WOODFORD STANLEY GOWAN PLUCKNETT NORRIS . CXXVII.-The Structure of the Enolic Forms of p-Keto-esters and @-Diketones. By NEVIL VINCENT SIDGWICK NoTEs.-Ray’s Supposed Triethylene Trisulphide. By GEORGE MACDONALD BENNETT and WIL;L;LBM AMBLER BEBY . The Physiological Action of Certain Benzthiazoles and Mercaptan Derivatives. By ROBERT FEWUS HUNTER . Preparation of L -21- Sulphophenyl- 3-methyl- 5-pyrazolone. By GEORGE REEVES The Micro-estimation of Methoxyl. By JOHN CHARLES SMSTH .Second Report of the International Committee of the Inter-national Union of Pure and Applied Chemistry on the Chemical Elements. International Atomic Weights 1925 Annual General Meeting . Universities as Centres of Chemical Research. Presidential Addreas. Delivered at the Annual General Meeting, March 26th 1925. By WILLIAM PALMER WYNNE D.Sc., F.R.S. . Obituary Noticea . . PAGE 852 870 875 882 885 892 898 907 910 911 91 1 912 913 918 936 95 CONTENTS. ... XU1 PAGE CXXVIII.-Nitro- and Amino-ethoxylutidine. By JOHN NORMAN COLLIE and GERALD BISHOP CXXIX.-Reactions of Triethylphosphine. By JOHN NOR-MA?scoLtIE . CXXX.-Derivatives of Semioxamazide. Part 111. By Fomm JAMES WILSON and ERIC Ckmms PICKERINQ CXXXI.4lour and Molecular Geometry.Part III. A Graphical Presentation of the Theory. By JAMES Mom CXXXII.-Studies in the Benzthiazole Series. Part III. The Pseudo-bases of the E-Substituted Benzthiazole Quaternary Salts. By LESLJE lKms.~n~.r. . CXXXIII.-The Compounds Formed by the Action of Bromine upon Benzaldehydephenylhydrazone. By FREDERICK DANIEL CHATTAWAY and ARTHTJ~ JOHN CXXXTV.-Ring-chain Tautomerism. Part XIII. Three-carbon Ring-chain Tautomerism in a Bridged Ring System. By JOHN W m BAKER CXXXV.-Synthesis of 5 5’-Dibromo-6 6‘-dimethoxy-2 2’-bisoxythionaphthen. By ROLAND BAT.TI G ~ H and EDWARD HOPE . CXXXVI.4ome Aromatic Chlorovinylarsines. By ARTHUR FREDERICK HUNT and EUSTACE EBENEZEB TURNER . CXXXVII.-Tesla-luminescence Spectra. Part V. Some Polynuclear Hydrocarbons.By W m z m HAXCLTON MCVICKER JOSEPH KENNETH MARSH and ALFRED WALTER STEWART . CXXXVIII.-The Mechanism of the Formation of Malachite from Basic Cupric Carbonate. By JACK REGINALD IMNS HEPBURN . CXXXIX.-Periodic Electrochemical Phenomena. By ERNEST SYDNEY HEDGES and JAMES ECKERSLEY MYERS . CXL.-The Photochemical Decomposition of Nitrosyl Chloride. By EDMIMD JOHN BOWEN and JOHN FRED-CXL1.-The Mercuration of Aromatic Substances. Part I. Toluene. By SAMTJEL COFFEY . CXLI1.-A Synthesis of 1 2-Dihydroquinaldine. By FREDERICK ALFRED MASON . CXLII1.-The Hydrates of Calcium Carbonate. By JOHN HUME . CXL1V.-The Interaction of Thiocyanogen with Unsaturated Compounds. By FREDERICK CHALLENGER and moms &OLD B o n . . WALKER ERICK fh4RJ? .962 964 965 967 973 975 985 990 996 999 1007 1013 1026 1029 1032 1036 103 XiV CONTENTS. CXLV.-The Potassium Chlororuthenates and the Co-ordination Number of Ruthenium. By S. H. CLIFFORD BRJGGCS . CXLVI.-The Reaction between Aromatic Aldehydes and Phenanthraquinone in presence of Ammonia. By ANUKUL CHANDRA SIRCAR and NIRMAL CEANDRA GUHA RAY . CXLVI1.-The Measurement of the Dielectric Constants of Liquids. By HERBERT HARRXS . . CXLVII1.-A Solid Antimony Hydride. By EDWARD JOSEPH WEEKS and JOHN GERALD FREDERICK DRUCE CXL1X.-Ring-chain Tautomerism. Part XIV. The Structure of Balbiano's Acid. By EUQENE ROTHSTEIN, ARNOLD STEVENSON and JOCELYN FIELD THOWE . CL.4tudies of Dynamic Isomerism. Part XVII. The Mutarotation of Aluminium Benzoylcamphor.By IRVINE JOHN FA-ER and THOUS MARTIN LOWRY CL1.-" Activated " Graphite as a Sorbent of Oxygen. By DONALD HUGH BANGCHAM and JOHN STAFFORD . . CLI1.-Investigations on the Dependence of Rotatory Power on Chemical Constitution. Part XXV. Three Optic-ally Active Alcohols containing a Phenyl Group and some Esters derived therefrom. By LESLIE FRANK HEWITT and JOSEPH KENYON . CLIII.-The Thermal Decomposition of Ammonia upon Various Surfaces. By CYRIL NORMAN HINSHELWOOD and ROBERT EMMETT BDRK . CLIV.-!I%e Labile Nature of the Halogen Atom in Organic Compounds. Part XI. The Halogenation of Ethyl Acetylsuccinate. By ALEXANDER KILLEN MACBETH and DAVID TRLLILL . CLV.-The Freezing Points of Hydrofluoric Acid. By JOHN DAVID CECIL ANTHONY and LAWSON JOHN HUDLESTON .. CLVI.-A Synthesis of Pyrylium Salts of Anthocyanidin Type. Part VI. Polyhydroxyflavylium Salts related to Chrysin Apigenin Lotoflavin Luteolin Galangin, Fisetin and Morin. By DAVID DOIQ PRATT and ROBERT ROBINSON . CLVI1.-The Action of Hydrogen Chloride on cycloHexyl-ideneazine and on cycloPentylideneazine. By WILLIAM HENRY PERKIN jun. and SYDNEY GLENN PRESTON PLANT . PAGE 1042 1048 1049 1069 1072 1080 1085 1094 1105 1118 1122 1128 113 OONTENTS. xv P4QE CLVIII.-The Additive Formation of Four-membered Rings. Part VII. The Synthesis and Division of some Di-methylene-1 3-oxaimines. By CHRISTOPHER KELK INGOLD . CL1X.-The Explosion of Ammonia with Carbon Monoxide and Oxygen. By JOHN WILLIAM BEESON and JAMES RIDDICK PARTINGTON .CLX.-Aromatic Esters of Acylecgonines. By WILLIAM HJERBEBT GRAY . CLXL-Strychnine and Brucine. Part III. The Position of the Methoxyl Groups in Brucine. By FRANCIS LIONS, WILLIAM HENRY PERKIN jun. and ROBERT ROBINSON CLXI1.-Investigations of the Dependence of Rotatory Power on Chemical Constitution. Part XXVI. Four Alcohols containing the Vinyl Group and some Esters derived therefrom. By JOSEPH KENYON and DOUGLAS ROSEBERY SNELLGROVE . CLXIIL-A Synthesis of Pyrylium Salts of Anthocyanidin Type. Part VII. The Preparation of the Antho-cyanidins with the Aid of 2 4 6-Triacetoxybenzalde-hyde. By DAVID DOIG WTT and ROBERT ROBINSON CLXIV.-A Synthesis of Pyrylium Salts of Anthocyanidin Type. Part VIII. A New Synthesis of Pelargonidin Chloride and of Galanginidin Chloride.By THOU MALKJX and ROBERT ROBINSON . CLXV.-Nitration of the Carbonate and Ethyl Carbonate of m-Hydroxybenzaldehyde. By FREDERICK ALFRED MASON [in part with H. JENgINSON] CLXVI.-The Tautomerism of Dyads. Part 111. The Effect of the Triple Linking on the Reactivity of Neighbouring Atoms. By EDITH HILDA INGOLD . Chemistry at Interfaces. A Lecture delivered before the Chemical Society on February 26th 1925. By SIR W m HARDY M.A.? Sec.R.8. . . . CLXVII.-The Ionimtion of Aromatic Nitro-compounds in Liquid Ammonia. Part I. By (%) MARGARET JOYCE FIELD WIILCAM EDWARD GAENER and CHRIS-TOP- CAIGER SMITH . . . CLXVIII.-The Conditions underlying the Formation of Unsaturated and Cyclic Compounds from Halogenated Open-ohain Derivatives.Part VII. The Influence of the Phenyl Group on the Formation of the CyclOPropene Ring. By WILHELM &XDX and JOCELYN FIELD . ! h O a P E . 1141 1146 1150 1158 1169 1182 1190 1195 1199 1207 1227 123 xvi CONTENTS. CLX1X.-The Directing Influence of the Methanesulphonyl Group. By RICHARD F’RANCIS TWIST and SAMUEL SMILES . CLXX.-3 3-Diethylpentane (Tetraethylmethane). By GILBERT T. MORGAN SYDNEY RAYMOND CARTER and ALBERT E. DUCK . CLXX1.-The Rotatory Dispersive Power of Organic Com-pounds. Part XVI. Halogen Derivatives of Camphor. Optical Superposition in the Camphor Series. By JOHN 0- CUTTER HENRY BURGESS and THOMAS MARTIN LOWRY . CLXXIL-The Molecular Condition of Phenol in Benzene Solution.By JAMES C. pHn;Ip and C. H. DOUGLAS CLXXII1.-Hepto- and Nono-dilactones. By GEORGE MACDONALD BENNETT . CLXXIV.4emicarbazones of Benzoin. Part I. By ISAAC VANCE HOPPER . CLXXV.-The Composition of Starch Iodide. By HUMPHREY DESMOND MURRAY. CLXXVI.-The Formation of d-2 2 4-Trimethylcycb-hexan-3-one- 1 -carboxylic Acid from d-Camphorquinone. By CHARLES STANLEY GIBSON and JOHN LIONEL CLXXVI1.-The Action of Halogens on Phenylhydrazones. Part 11. The Action of Chlorine. By JAMES ERNEST HUMPHRIES HENRY HUMBLE and ROY EVANS By FREDERICK DANIEL CHATTAWAY and GEORGE DAVID PARKES . CLXXIX.-Compoun& of Tervalent Molybdenum. Part 111. New Oxalates. By WILLIAM WARDLAW and WELIAM HENRY PARKER CLXXX .-Bromination of 4’-Amino- 1 -phenyl-5-methyI-benzthiazole and of 1 1-Bisbenzthiazole.By ROBERT FERGUS H ~ E R . CLXXX1.-The Decomposition of Hydrogen Peroxide by Cobaltic Hydroxide. By FREDERICK GERALD TRYHORN and GILBERT JESSOP . CLXXXI1.-or- Acenaphthaquinoline. By JESSIE STEWART CLXXXII1.-The Solubility of Sulphur Dioxide in Water and in Aqueous Solutions of Potassium Chloride and Sodium Sulphate. By JOHN CHRISTOPHER HUDSON . CLARK . SWONSEN . CLXXVII1.-The Action of Azides on Toluquinone. PAQE 1248 1252 1260 1274 1277 1282 1288 1294 1304 1307 1311 1318 1320 1331 133 CON!rENTS. xvii PAQP CLXXXIV.-Low Temperature Oxidation at Charcoal Surfaces. Part I. The Behaviour of Charcoal in the absence of Promoters. By ERIC KEIGHTLEY RIDEAL and WINIFRED MARY WRIGHT .CLXXXV.-The Isomerism of the Oximes. Part XXII. The Configuration of the Aldoximes. By OSCAR L. BRADY and GERALD BISHOP . CLXXXVI.-A Spectroscopic Study of the Combustion of Phosphorus Trioxide and of Hydrogen Phosphide. By CLXXXVI1.-The Action of Phosphorus Pentachloride on 2-isoNitroso- 1 -hydrindones. By ROBERT DOWNS HAWORTH and HERBERT SEEPPARD PINK . CLXXXVIII.-Studies of Dynamic Isomerism. Part XVTII.-The Mechanism of Mutarotstion. By THOU h ! m N LOWRY . . CLXXXIX.-Studies of Dynamic Isomerism. Part XIX. Experiments on the Arrest of Mutarotation of Tetra-methylglucose. By THOMAS MARTIN LOWRY and EVAN M ~ ~ E w RICHARDS . CXC.-The Constitution of Soap Solutions in Presence of Electrolyfxs. Potassium Laurate and Potmsium Chloride. By WIUIAM ~ O R D QUICK .CXC1.-Plant Cuticles. Part I. Modern Plant Cuticles. Studies in the Composition of Coal. By VERNON Horns LEGC and RICHARD VERNON WHEELER . CXCI1.-The Spatial Structure of cycloParafihs. Part I. A New Aspect of Mohr’s Theory and the Isomerism of Decahydronaphthalene. By WILFRED ALAN WIGFITMAN CXCIII.-/3-Piperonylpropion.itrile and some Derived Sub-stances. By WILSON BAKER and ROBERT ROB~SON . CXCIV.-Synthetical Experiments in the isoQuinoline Group Part I. By ROBERT DOWNS HAWORTH and WILLIAM HENRY PERKIN jun.. CXCV.-Synthetical Experiments in the isoQuinoline Group. Part II. By ROBERT DOWNS HAWORTH WILLIAM HENRY PEW jun. and JOHN RANKIN . CXCVI.-Synthetical Experiments in the isoQuinoline Group. Part III. By ROBERT Doms HAWORTH and WILLTAM HENRY PERKIN jun..CXCVII.-Synthetical Experiments in the isoQuinoline Group. Part IV. By ROBERT DOWNS HAWORTH and WILTJABX HENBY PERKIN jun.. Jams ETHEL~US . 1347 1357 1362 1368 137 1 1385 1401 1412 1421 1424 1434 1444 1448 145 xviii CONTENTS. CXCVIII.-Synthesis of 2 3 10 11-Bismethylenedioxy-protoberberine and 6 7 3’ 4’-Bkmethylenedioq-protopapaverine. By JOHAKNES SYBIZANDT BUCK, W m HENRY PERKIN jun. and m o w STEVENS STEVENS CXC1X.-Alcohols of the Hydroaromatic and Terpene Series. Part IV. a- and p-Fenchyl Alcohols and some Esters derived therefrom. By JOSEPH KENYON and &OLD EDWARD MEAD -TON . NoTEs.-The Atomic Volume of Manganese. By A L ~ N N. Molybdenum Pentoxide. By Wnrr;ra~ WARDLAW and FRANK &OLD NICHOLLS .. Chlorobenzthiazole Dibromide. By ROBERT FERGUS HUNTER. A Laboratory Method of Preparing p-Benzoquinone. By REGINALD CRAVEN and WIUIBM ALEXANDER TURNER DUNCAN. Reduction of the Bromoanthraquinones. By EDWARD DE BARRY BARNETT and JAMES WILFRED COOK . The Reduction of Anethole Nitrosochloride by Sfannous Chloride and Hydrochloric Acid. By JOHN BALDWIN SHOESMITH and ROBERT HENRY SLATER . . Oxidations in Turpentine and Olive Oil. By ERNEST WALKER. . . . . . . . CC.-Synthetical Experiments in the Naphthyridine Groups. By JOHN MASSON GULLAND and ROBERT ROBINSON . CCI.-The Rotatory Dispersive Power of Organio Com-pounds. Part XVII. p- and d3ulphonic Derivatives of Camphor. By EVAN M i m w R1-s and T H O U lkL4Rm LOWRY . . . CCII.-Sulphur Sesquioxide.By I s m Voam and JAMES REDDICK PARTINQTON . . . CCIII.-!l%e Parachor and Chemical Constitution. Part I. Polar and Non-polar Valencies in Unsaturated Corn-pounds. By S ~ L SUGDEN JOHN BRENT REED, and HENRY W ~ S . CCIV.-The System Chromium TrioxideBoric Acid-Water. By LIONEL FELIX GILBERT . . . . CCV.-!l!he Dissociation Constants of Selenious Acid. By J m s STUART Wmcox and EDMUND BRYDQES RUDHALL PRIDEAUX . . CAMPBELL . . . PAQB 1462 1472 1487 1487 1488 1489 1489 1490 1491 1493 1503 1514 1525 1541 154 CO2!mENTs* xix PAGE CCVI.-The Interaction of b b o n Dioxide and Hydrogen on the Surface of Tungsten. By Cwrr NO-HINSHELWOOD and CEABLES Ross pB;I(sHBBD CCVII.-The Relation of Homogeneous to Catdy8ed Re-actions.The Catalytic Decomposition of Hydrogen Iodide on the Surface of Gold. By Cwn; NORMAN HINSHELWOOD and CEURLES Ross PRIGHARD . . CCVIII.-The Adsorption of Water from the Gas Phase on P h e Surfam3 of Glass and Platinum. By IVAN ROY MC€€AFFIE and SABS LENHEX CCIX.-A New Method of Diagnosing Potential Optid Activity. Part I. The Optical Activity of Chloro-bromomethandphonic Acid. By Jom READ and ANN MORTIMER MCMATH. CCX.-The Nitration of m-Chlorophenol. By H~BBERT HENBY HODQSON and RUNCIS HABZLY MOORE . CCXI.-Polynucleaz Heterocyclic Aromatic Types. Part II. Some Anhydronium Bases. By JAMES WILSON ARMIT and ROBEBT ROBINSON . CCXII.-The Nitration of m-Meconine. By JNA”DEA NATH RAY and ROBEBT ROBINSON . . . CCXIII.-The System Sodium Sulphitdkdium Hydroxide-Water.By DAIZ~EI LLEWELLYN HAMMICK and JOHN CCXIV.-Oxidation Products of Oleic Acid. Part I. Con-version of Oleic Acid into Dihydroxyshric Acid and the Determination of the Higher Saturated Acids in Mixed Acids from Natural Sources. By aaTHw LAPWORTH and EDWARD NEVILLE MOTTBAM . . CCXV.-The Action of Hydrogen Peroxide on Limonene. By JAMES SWORD . . a n d E i m x ~ S m m m . b 8 CCXVII.-Studies of the Glucoaides. Part III. The Syn-the& of “Thioindican.” By JAMES CELADC and CCXVLII.-Echitami.ne. By JOHN AUGUSTUS GOODSON and CCXIX.-Chenopodium Oil. Part II. The Hydrocarbon Fraction. By THOMAS ANDEBSON HENBY and HUMPHREY PAGET . 8 . CCXX.-isoQuinoline Derivatives. Part IX. Preparation and Reduction of isoQuinoline and ifs Derivatives.By ROBERT FORSYTH CHARLES IQNATIUS KELLY and FRANK LEE PYUN. 8 . . ALEXANDER ChJRBIX . CCXVI.-H~~~O@~KB%. By JOHN THOMPSON MABSH ALEXANDER KILLEN fiCBETH . . . 8 THOMAS &TDEasON HENBY . 1566 1552 1559 1572 1599 1604 1618 1623 1628 1632 1633 1637 1640 1649 165 xx CONTENTS. CCXXI.-The Surface Tensions of Aqueous Phenol Solutions. Part PI. Activity and Surface Tension. By ARTHUR KENNETH GOARD and ERIC KEIGHTLEY RIDE& . CCXXII.-Bromination of Acyl Derivatives of Phenyl-hydrazine. Preparation of 2 4-Dibromophenyhydr-azine. By JAMES EIWEST HUMPHRIES and ROY EVANS CCXXIII.-The Structure of a-Campholytic Acid. A Correction. By JUAN PEDIQE CHARLES CHBNDRASENA, CHILISTOPHER KELK INGOLD and JOCELYN FIELD CCXXIV.-!l!he Formation and Stability of spiro-Com-pounds.Part XII. Further Evidence for the Multi-planaz Configuration of the ycloHeptane Ring. By JOHNW~~AMBAEER . CCXXV.-!Cridentate Groups in Complexes of Tetrahedral and Octahedral Symmetry. By J. D. MLLIN S m . CCXXVI.-The Action of Halogens upon m- and p-Nitro-beddehydephenylhydrazones. By FREDERICK DANTEL CHAITAWAY and ARTHUR JOHN WALKER . CCXXVII.-The Tautomerism of Dyads. Part IV. New Evidence of the Tautomeric Mobility of Oximes. By JOHN PREEDY GRXFFITHS and CFXRXSTOPHER KEIX INGOLD CCXXVIII.-Synthetical Experiments in the isoQuinoline Group. Part V. Synthesis of Substances allied to Oxyberberine. By ROBERT DOWNS HAWORTH WII;LZBM HENRY PERKIN jun. and HERBERT SELEPPARD PINK. CCXXTX.-Reaearches on Sulphuryl Chloride.Part III. The Influence of Catalysts on the Chlorination of Toluene. By OSWALD SILBERRAD CHAS. A. SILBERRAD and BEATRICE PARKE . CCXXX.-Stereoisomeric Azo-dyes. By GILBERT T. MORGAN and DONS GEORGE SKINNER CCXXXI.-Theories of Polar and Non-polar Free -ties. A Practical and Theoretical Reply to some Recent Criticisms and Comparisons. By GEORGE NORAWN BURKHARDT and ARTHUR LAPWORTH CCXXXII.-The Estimation of Arsenic in Organic Com-pounds. By GEORGE NEWBERY . By PEI~CY CORLETT AUSTIN . By LESLIE HENRY ALFRED HOLMES and EUSTACEBENEZER T~RNER !hiORPE . . NOTES.-T,jthium Arc Spectrum for Polarimetric Use. Potassium Antimonoxdate. PAOR 1668 1676 1677 1678 1682 1687 1698 1709 1724 1731 1742 1751 1752 175 CONTENTS.xxi PAQB A Simplified Method of Micro-combustion the Micro-Dennstedt Method. By CASIMIE FUXK and STBNISL~S KON . . CCXXXTTI.-Arylselenoglycollic Acids. By GILBEBT T. MORGAN and WILLIAM HENRY PORRITT CCXXXTV.-Aromatic Derivatives of Germanium. By G ~ E R T T. MORGAN and €€ABBY DUGALD KEITH DREW CCXXXV.-The Stability of Additive Compounds between Esters and Acids. By JAMES KENDALL and JAMES ELIOT BOOGE . CCXXXVI.-Additive Compounds in the Ternary System : Ester-Acid-Water. By JAMES KENDALL and CECIL VICTOR KING . CCXXXVII.-The Preparation of Phthalamic Acids and their Conversion into Anthranilic Acids. By ERNEST CHAPMAN and HENRY STEPHEN . CCXXXVIII.-Derivatives of 8-0-Aminobenzoylvaleric Acid. By MARGARET JOYCE PATERSON and SYDNEY GLENN PRESTON PLANT .CCXXXIX.-Bismuth Dihydride. By EDWARD JOSEPH WEEKS and JOHN GERALD FREDERICK DRUCE . CCXL.-The Nature of the Alternating Effect in Carbon Chains. Part 111. A Comparative Study of the Directive Efficiencies of Oxygen and Nitrogen Atoms in Aromatic Substitution. By ERIC LEIGHTON H o r n s and CHRISTOPHER K E ~ INGOLD . CCXLI.-Syntheses of Disulphoxides. By DAVID TEMPLE-TON GIBSON CECIL JAMES MILLER and SAMUEL SMILES CCXLII.-Studies of Electrolytic Polarisation. Past III. The %ion Layer. By SAMUEL GLBSSTONE . CCXLIII.-The 4- and 5-Nitro-1 2-Dimethylglyoxalines. By VINAYAK KESHAV BHAOWAT and FRANK LEE PYAIAN CCXLIV.-Some Physical Properties of Aniline and its Aqueous Solutions. By 1MBLcom PERCIVAL APPLEBEY and PEMXVAI GLYN DAVIES . CCXLV.-Osmotic Pressure by the Solubility Method in Concentrated Solutions.By MALCOLM PERCIVAL APPLEBEY and PERCIVAL GLYN DAVIES CCXLVI.-Studies on the Walden Inversion. Part IX. The Influence of the Solvent on the Sign of the Product in the Conversion of p-Bromo- f%phenylpropionic Acids into B-Hydmxy- p-phenylpropionamides. By GEOIWE SENTIER and ALLAN MILES WARD . . . 1754 1755 1760 1768 1778 1791 1797 1799 1800 1821 1824 1832 1836 1840 184 xxii CONTFJTTS. CCXLVI1.-The Coloura Produced by the Action of Sulph-uric Acid upon Some Hydrazones. By FREDERICK DANIEL CHATTAWAY STANLEY JOHN IRELAND and ARTHURJOHNwiiLKER . Part XL. Constitution of Manasse’s Hydroxycamphor. By JKumm ONSLOW FORSTER and PRAJAIUM PRABHAS-CCXL1X.-A New Synthesis of Arylazoaldoximes.By =OMAS KENNEDY WALKER . CCL.-Angles of Contact and Polarity of Solid Surfaces. By NEIL K. ADAM and G-EFLT JESSOP . ELI.-The Parachor and Chemical Constitution. Part 11. Geometrical Isomerides. By SAMUEL SUGDEN and HENBY W~TTAKEB. CCLI1.-A New Synthesis of Aldehydes. By HENRY STEPHEN. CCLIII .- p P‘ -Dichloro- and p p ’ -Dibromo-die thy1 Selenides and their Simple Halogen Derivatives. By HUGH CHESTER BELL and CHARLES STANLEY G~BSON . CCL1V.-Reduction Products of the Hydroxyanthra-quinones. Part VI. By ARTHUR GEORGE PERKIN and GEN. YODA . CCLV.-A Wandering of the Acetyl Group during Methyl-ation. By ONRO KUBOTA and ARTHUR GEORGE PER= CCLVI.-Hydrogen and Oxygen Electrode Titrations of Some Dibasic Acids and of Dextrose.By HUBERT THOMAS STANLEY BRITTON . . CCLVI1.-Researches on Residual Affinity and Co-ordin-ation. Part XXIV. Heats of Chelation of Dithiolated Metallic Halides. By GILBERT T. MOMAN SYDNEY RAYMOND CARTER and WILLIAM FINNEMORE -ISON CCLVII1.-The Rotatory Dispersion of Derivatives of Tartaric Acid. Part 11. Acetyl Derivatives. By PERCY CORLETT AUSTIN and JAMES RITCHIE PARK . CCL1X.-The Chemietry of Petroleum. Part 11. The Action of Sodium Hypochlorite on Sulphur Compounds of the Tspes found in Petroleum Distillates. By STANLEY FRANCIS BIRCH and WOODFORD STANLEY Gowm PLUCKNETT NORRIS . CCLX.-The Action of Formic Acid on certain Sesqui-terpenes. By JOHN MONTEATH ROBERTSON CARL ALOYSIUS HE= and GEORGE GERALD HENDEBSON . CCXLVIII.-Studies in the Camphane Series.HANKERSHUKIA . PAGB 1851 1855 1860 1863 1868 1874 1877 1884 1889 1896 1917 1926 1934 194 CONTENTS. CCLXI.-Cryoscopic Measurements with Benzene. By EDWARD RICHBSD JONES and CHARLES R. BUBY . CCLXII.-The Condensed Ternary System Phenol-Water-Salicylic Acid. By CHaaCEs REYNOLDS BAILEY . CCLXIII.-Carboxycamphoranilic Acids. By BEAHAN SINGH and RAM SINGH . CCLXLV.-A Synthesis of Datiscetin. By JAN KALFF and ROBERT ROBINSON . CCLXV.-!l?he Synthesis of certain 2-Styrylchromonol Deriv-atives. By ROBERT ROBINSON and Jmzo SEINODA . CCLXVL-Synthetical Experiments in the isoFlavone Group. Part I. By WILSON BARRR and ROBEBT ROBINSON . CCLXVIL-Oxidation Products of Oleic Acid. Part II. Degradation of Dihydroxystearic Acid.By B a r n LAPWORTH and EDWARD NEVILLE MO~RAM . CCLXVIII.-The Effect of Ultra-violet Light on Dried Hydrogen and Oxygen. By -BERT BRERETON BAKER and MARGARET CARLTON . CCLXIX.-Imino-aryl Ethers. Part III. The Molecular Rearrangement of N - Phenylbenziminophenyl Ether. B~ARTHUBWILLIAMCHA.PMAN . CCLXX.4ubstitution in Derivatives of Quinol Ethers. By LEON RUBENSTEIN . CCLXXI.-!L'he Relative Rates of Conversion of Phenoxy-phenyldichloroarsine and its Chloro-derivatives into Chlorophenoxarsines. By ELWYN ROBERTS and EUSTACEBENEZZC~ TUESER . . CCLXXII.-2-Amino-4 5-dimethylglyoxaline. By [the late] RICHARD BURTLES and FRANK LEE PYBUN . CCLXXII1.-A Synthesis of a-Dicentrine. By ROBERT DOWNS HAWORTH WILLIAM HENRY PERKIN jun. and JOHN R m m . CCLXX1V.-Aminobenzthiazoles.Part I. 1-Anilinobenz-thiazole and its Tolyl Homologuea. By ROBERT FERGUS HUNTER. CCLXXV.-The Amino-4-pyridones. By WILLIAM HAUGH-CCLXXVI.-Researches on Residual Afkity and Co-ordin-ation. Part XXV. A Quadridenfate Group Con-tributing Four Associating Units to Metallic Complexes. By GILBZRT T. MOSGAN and 3. D. MAIN SMITH . TON CROWE . 1947 1951 1966 1968 1973 1981 1987 1990 1992 1998 2004 2012 2018 2023 2028 203 XXiV CONTENTS. CCLXXVI1.-The Synthesis and Reactions of 1 -Aniho-cydopentane- 1 -carboxylic Acid. By SYDNEY GLENN PRESTON PLANT and JOHN ERNEST FACER CCLXXVII1.-The Action of Nitrogen Dioxide on Anthra-cene Derivatives. By EDWARD DE BARRY BARNETT CCLXX1X.-The Constitution of Indian Kamala. Part I.By SIKHIBHUSHAN DUTT . CCLXXX.-The Decomposition of Carbon Monoxide in the Corona due to Alternating Electric Fields. Part I. By MIGUEL CRESPI and ROBERT WINSTANLEY LVNT . CCLXXXI .-Anode Phenomena in the Electrolysis of Potassium Ethyl Malonate. By JOHN B-AITE ROBERTSON . CCLXXXI1.-The Reaction of Bromine with Aliphatic Acids. Catalytic Effect of Acyl Halides. By HERBERT BEN WATSON . CCLXXXII1.-Homologues of 2 2’-Diquinolyl. By EDWARD JOHN VENN CONOLLY CCLXXX1V.-The Thermal Decomposition of Ozone. By ROBERT OWEN GRIFFITH and ANDREW MCKEOWN . CCLXXXV.-The Dissociation Pressures of Hydrated Double Selenates. By JOHN FERGUSON . CCLXXXV1.-Researches on Chromammines. Part 11. Hydroxopentamminochromic Salts and Electrical Con-ductivities of Chromammines.By HERBERT JOSEPH CCLXXXVII .-Electrometric Studies of the Precipitation of Hydroxides. Part I. Precipitation of Magnesium, Manganous Ferrous Cobalt Nickel and Thorium Hydroxides by Use of the Hydrogen Electrode. By HUBERT THOMASTANLEY BRITTON CCLXXXVIII .-Electrometric Studies of the Precipitation of Hydroxides. Part 11. The Precipitation of the Hydroxides of Zinc Chromium Beryllium Aluminium, Bivalent Tin and Zirconium by Use of the Hydrogen Electrode and their Alleged Amphoteric Nature. By HUBERT THOMAS STANLEY BRITTON . CCLXXXIX.-Electrometric Studies of the Precipitation of Hydroxides. Part 111. Precipitation in the Cerite Group of Rare Earths and of Yttrium Hydroxide by Use of the Hydrogen Electrode. By HUBERT THOMAS STANLEY BRITTON . .SEYMOURKING . PAGE 2037 2040 2044 2052 2057 2067 2083 2086 2096 2100 21 10 2120 214 CONTENTS. CCXC.-Electrometric Studies of the Precipitation of Hydroxides. Part IV. Precipita;tion of Mercuric, Cadmium Lead Silver Cupric Uranic and Ferric Hydroxides by Use of the Oxygen Electrode. By HTJBERT THOUS STANLEY BRITTON . CCXC1.-The Interaction of Ethyl Acetoacetate and 0-Hydroxydistyryl Ketones. Part 11. By ISIDOR Mo- HEILBRON THOUS ALFRED FORSTER and ABRAHAM BRUCE WHITWORTH . Part II. The Reactivity of the 2-Methyl Group in the 4-Quh-azolone Series. By ISIDOR MORRIS HEILBRON FRANCIS NOEL KITCHEN EDWARD BURDON Paams and GEORGE DONALD S m o ~ . NOTEs.-hparation of the Phenylcarbamyl Derivatives of Nitrophenols. By Oscm L.BRADY and JACK HaRRLs d-Mannitol from Gardenia turgidu. By -TIN O N S ~ W FORSTER and KESHAVIBH ASWATH NARAIN RAO . CCXCIII.-!T!he Velocity of Benzylation of certain Amines. Part 11. By DAVID HENRY PEACOCK . CCXCIV.-A New Peroxide of Barium. By MARGARET CCXCV.-!I'he Action of Aldehydes on the Grignard Reagent. Part 111. By JOSEPH M B R S m . CCXCVI.-Optical Activity and the Polarity of Substituent Groups. Part II. Menthyl Esters of Substituted Acetic Acids. By HAROLD GORDON RULE and JOHN SMITH . CCXCVI1.-X-Rays and the Constitution of the Hydro-carbons from Parafb Wax. By STEPHEN HBRVEY PIPER DENNIS BROWN and STANLEY DYMENT . CCXCVIII.4onstituents of Myqorum laetum Forst (the " Ngaio "). Part I. By F'REDERICK HENRY MCDOWAIX CCXC1X.-An X-Ray Examination of Maleic and Fumaric Acids.By KATHLEEN YARDLEY . CCC.-Purification of Phosphoric Oxide. By HENRY CCC1.-Determination of Metals Dissolved in Mercury. Rapid Method of Purifying Mercury. By ALEXANDER SWTEE RUSSELL and DEREK CURTIS EVANS CCCI1.-The Alcoholysis of Trinitroanisole and Trinitro-phenetole. By OSCAR L. BRADY and HAROLD V. HORTON . CCXCII.4hemical Reactivity and Conjugation. &ELLTON. WHITAEER . . 2148 2159 2167 2175 2176 2177 2180 2184 2188 2194 2200 2207 2219 2221 223 xxvi c o m m . CCCIII.-!l%e Supposed E’ormation of 1 2 4-Oxadi-imine Rings from Nitroso-compounds and Methylenearyl-amines. By GEORGE NORMAN B-T ARTHUR LAPWORTH and EDWIN BREW ROBINSON . CCC1V.-The Properties and Constitution of Coal Wins.Studies in the Composition of Coal. By WILFRID FRANCIS and RICHARD VERNON WHEELER CCCV.-The Coagulation of a Colloidal Solution by Hydrogen Ions. By ALAN B. WEIR . CCCV1.-The Constitution of the Thionic Acids. By ISRAEL VOGEL . CCCVII.-n”o-Thioanthracene Derivatives. Part 11. Di-anthranyl Disulphide and Dianthranyl Tetrasulphide. By WILLIAM HERBERT COOKE ISIDOR MORRIS HEIL-BRON and GEORQE HUGH WALKER . CCCVIII.-The Reaction between Sodium Hypobromite and Carbamide. By MAXWELL BRUCE DONALD . CCC1X.-Nitrosation of Phenols. Part 11. Nitrosation of 3-Bromo- 2-Bromo- 3-Iodo- and 2-Iodo-phenol. Evidence for the Nitroso-f ormula of 4-Nitrosophenol. By HERBERT HENRY HODGSON and FRANCIS HARRY MOORE . CCCX.-Nitration of Phthal- and Succin-p-tolil. By OSCAR L.BRADY WILLIAM G. E. QUICK and WALTER F. CCCXI.4ubstitution in Vicinal Trisubstituted Benzene Derivatives. Part 111. By LEON RUBENSTEIN . CCCXI1.-Aminobenzthiazoles. Part II. Naphthylamino-naphthathiazole Derivatives. By ROBERT FERGUS HUNTER . CCCXIII.-An Investigation of the Action of Halogens on 2 4-Dimethylbenzoyl Chloride. By WILLIAM HENRY PERKIN jun. and JOHN FREDERIC SMERDON STONE . CCCXIV.-Synthesis of Substituted 4-Keto-1 2 3 4-tetra-hydroquinolines and an Attempt to Syntheaise 4-Keto-1 2 3 4-tetrahydroisoquinoline. By GEORQE ROGER CLEMO and WILLIAM HENRY PERXIN jun. CCCXV.-Interactions of Tellurium Tetrachloride and Aryl Alkyl Ethers. Part I. By GILBERT T. MORGAN and HARRY DUGALD KEITH DREW . CCCXVI.-A New Aspect of the Photochemical Union of Hydrogen and Chlorine.By RONALD G. W. NORRISH. CCCXVII.-Selective Solvent Action. Part IV. Cryoscopy in Mixed Solvents. WELLING . By ROBERT WRIGHT . PAGE 2234 2236 2245 2248 2250 2255 2260 2264 2268 2270 2275 2297 2307 2316 233 ocCXVIII.-Co~our and Molecular Geometry. Part IV. Explanation of the Colours of the Cyanine Dyes. By JAMESMOIR . . CCCXIX.-The Influence of Nitro-groups on the Reactivity of Substituenfs in the Benzene Nucleus. Part VIII. 2 3- and 2 5-Dinitro-~-chlorotuenes. By Jrrad~s K.ENNER CHARLES WILLTAM TOD and ERNEST WITHAM CCCXX.-The Formation of Chromones.-A Criticism. By WESON BAKER . CCCXXI.-The Formation and Stability of Associated Alicyclic Systems. Part 11. The Formation and Dis-ruption of Dicyclic Dihydroresorcinols.By EXNEST OLD FARMER and JOHN Ross CCCXILI1.-Applications of Thallium Compounds in Organic Chemistry. Part 11. Titrations. By GEOEGE HALLATT CHRISTIE and ROBERT (~LARLES MENZIES . CCCXXIII.-The Reactions of Azoxy-compounds. Part I. The Action of Light. By WILLIAM MURDOCH CWMMINQ and GEOWE STRATON FERRIEE . CCCCXXIV.&-ordinated Compounds of the Alkali Metals. Part II. By N m VINCENT SID~WICK and FREDEBJCK MASON BREWER . CCCXXV.-Studies in the Configuration of aa’-Dibromo-dibasic Acids. Part IT. The aa’-Dibromoglutaric Acids. By HARRY RAYMOND ING and WILLJAM HENRY PERKIN, jun. CCCXXVI.-The Catalysis by Alumina of the Rertction between Ethyl Alcohol and Ammonia. By GORDON W~JAIKDORRELL . CCCXXVII.-Substituted k?ofiazomethanes.By FRED -EEUCK DANIEL CHATTAWAY and ARTHUR JOHN WALKER CCCXXVIII.-The Isomerism of the Oximes. Part XXIII. Acyl Derivatives. By OSCAR L. BRADY and GEBALD PATRICK MCHUGH . Part XXIV. 4-Methoxy-3-methyl- 3-Nitro-4-methyl- and Some ortho-Substituted Benzaldoximes. By OSCAR L. BRADY, ANTOINETTE N. COSSON and ARTHUR J. ROPER . CCCXXX.-The Periodic Crystallisation of Pure Substances. By ERNEST SYDNEY HEDGES and JAMES ECXERSLEY M Y E ~ . CCCXXX1.-The Rotation-Dispersion of Optically Active Compounds. Dimethoxysuccinates and Nicotine. By THOMAS STEWART PAWERSON and JAMES DAVIDSON FULTON . . CCCXXIX.-The Isomerism of the Oximes. 2338 2343 2349 2358 2369 2374 2379 2387 2399 2407 2414 2427 2432 243 xxviii CONTENTS.CCCXXXII .-p-Dimethylaminodiphenylacetic Acid. By DAL~SINGH . NoTEs.-Selenium as a Chlorine Carrier. By OSWALD SILBERRAD and CHARLES A. SILBERRAD . A Simple Form of Gas Circulating Apparatus. By A. R. PEARSON and J. S. G. THOMAS The Action of Metals on Dipentene Dihydrohalide. Re-paration of a Synthetic Diterpene. By KENNETH CHARLES ROBERTS . CCCXXX1II.-Negative Adsorption. The Surfme Tensions and Activities of Some Aqueous Salt Solutions. By ARTHUR KENNETH GOARD . CCCXXX1V.-Polarity Theories and Four-membered Rings. The Non-existence of 2 3 3-Triphenylmethylene-1:2-oxaimine. By GEORGE NORMAN BURKEIARDT, ARTHUR LAPWORTH and JAMES WALKDEN CCCXXXV.-The Distribution of Pyridine between Water and Benzene. By ROWLAND MARCUS WOODMAS and ALEXANDER STEVEN CORBET .CCCXXXVI.-A Circulation Apparatus for Gases. By NITYA GOPAL CHATTERJI and GEORGE INGLE ~ C H . CCCXXXVI1.-The Cyanine Dyes. Part IX. The Mechan-ism of the Condensations of Quinaldine Alkyliodides in Presence of Bases. By WIILIAM HOBSON Mrus and RICHARD RAPER . CCCXXXVII1.-Dibenzylquinaldine. By WILLIAM HOB-SON MILLS and ARNOLD THOMAS AKERS CCCXXX1X.-The Resolution of an Asymmetric Arsenic Compound into its Optically Active Forms. By WIL-LIAM HOBSON MILLS and RICHARD RAPER CCCXL.-The Production of Oxide Films on Copper at the Ordinary Temperature. By ULICK RICHARDSON EVANS CCCXLL-The Electrical Conductivity of Phosphorus Penta-chloride. By GEORGE WILLL4M FRASER HOLROYD, HARRY CHADWICK and JOSEPR ERNEST HALSTEAD MITCHELL . CCCXLI1.-The Occurrence of Sylvestrene.By B. SANJ~VA RAO and JOHN LIONEL S~ONSEN . CCCXLII1.-The Colorimetric Dissociation Constants of 3 5-Dinitrocatechol and 4 6-Dinitroresorcinol. By FRANK CHARLES LAXTON EDMTJND BRYDGES RUDHALL PRIDEAUX and WILLIAM HOWARD RADFORD . . . PAQE 2445 2449 2450 2451 2451 2458 2461 2464 2466 2475 2479 2484 2492 2494 249 CONTENTS. coCXLIV.4ymmetrical Substitution Derivatives of Tri-methylene Dibromide and Pentamethylene Dibromide. By WILLIAM HOBSON Mrraa and LEsm B m s . CCCXLV.-The Codiguration of the Ammonium Ion. By WIL;LI&M HOBSON n(mrr,ci and ERNEST HENRY W ~ ~ B ~ E N CCCXLVI.-The Correlation of Absorption Spectra with Ionisation in Violuric Acid. By RICHABD Ar;aN MOBTON and AaTKTJa H~OLD * P ~ B .CCCXLVII.-The Parachor and Chemical Constitution. Part III. Orientation Isomerism in Aromatic Com-pounds. By Smm SUGDEN and HENBY W m s . CCCXLvIzI.-The Conversion of r- Phenyl-a-naphthylgly-collic Acid into Ketones. By ALEX. MCKENVE and HAROLDJAMESTATTEBSALL . CCCXLIX.-Olefinic Terpene Ketones from the Volatile Oil of Flowering Tag& gkcndulifera. Part I. By THOU GILBERT HENRY JONES and FRANK BEB;BY S m . CCCL.-The Isomerism of the Styryl Akyl Ketones. Part II. The Isomerism of the Homologues of 2-Hydroxystyry1, and of 3-Methoxy-4-hydroqstyryl Methyl Ketones. By ~ X A N D I E R MCGOOKIN and DONALD JAMES S~CLILIB;. C(XI;I.-The Relationship of Salts in Dilute Aqueous Solution i18 determined by their Influence on the Critical Solution Temperatnre of the System Phenol-Water.By JOHN HE~SEBT CARRINGTON Lou= ROBEBT &-ON and W m HAMILTON PATTERSON . CCCLII.-Studies of Equilibrium in Systems of the Tspe Nickel 8ulphateWater at 30". By BERT h m CAVEN and THOUS Comm Mrrmmu CCCLIII.-The System Silver Sulphate-Aluminium Sulphate Wabr at 30". By ROBERT IbLctzm CAVEN and THOUS CORLETT-. CCCLIV.-Investigafions on the Dependence of Robtory Power on Chemical Constitution. Part XXVII. The Optical Properties of n-Algyl p-Toluenesulphinates. By HENRYpHII;ups . CCCLV.-The Relation between Chemical Constitution and Pungency in Acid Amides. By EDWARD cH&RLBIs SNELL JONES and FRANK LEE Pnux A.&(SO*) -B€"S04-H,0. Pad 11. Aluminium Sulph&+ . . xxix PAeB 2502 2507 2514 2517 2522 2530 2539 254.4 2549 2550 2552 2588 cccLvI.-The Equilibrium in the Systems Aluminium Sulphatdhpper Sulphate-Water and Aluminium Sul-phate-Femw Sulphate-Water at 25".By Vmcm JOSEPH Occms~aw . . 259 CCCLVII.-Thn Effect of Gum Arabic and other Emulsifiers on the Acid Hydrolpis of Estera in Heterogeneoua Systems. B~ROBEBTCHBISTIES~ . CCCLVIII.-An Investigation of the Effect of DBerential Aeration on Corrosion by meam of Electrode Potential Measurements. By A. L. MCAULAY and F. P. BOWDEN CCCLIX.-Production of cydoTelluripenta4ediolle Di-chlorides. By GILBERT T. MOMAN . OCCLX.-Tnteractions of Tellurium Tetrachloride and Mono-ketones. By GILBERT T. MORGAN and OLIVER CECIL ELVINS . CCCLXI.-Trypanocidal Action and Chemid Constitution.Part 11. Arylamides of CAminophenylarsinic Acid. By HAROLD KING and WIJXJAM OWEN MUECH CCCLXII.-The Action of Nitrous Acid upon Amidea and Other ‘cAmin~”-compounds. By ROBERT HENBY ADERs3ibaMEE . . . . . cccLxIII.-Solubility Influences. Part I. The Effect of some &lb Sugars and Temperature on the Solnbility of Ethyl Acetate in Water. By SAMUEL GLASSTONE and ALBEBT Porn . the m m i e l - f i h Readion. By bTaaR &EDEm2L-and EUSTACE EBENEZER TUERER . . (xxLxV.-yf-Dichlorodipropyl Sulphide. By GEOWE M~CDONALD BENNETT and ALFRED LOUIS HOCK . cccL;IIVI.-Re+cpnrche8 on Sulphuryl Chloride. Part IV. Further Studiea an a New Chlorinating Agent. Pre-paration of Polychloro-derivatives of Toluene. By OSWALD SILBEEEUD. . CCCLXVII.-Muction Products of the Hydroxyanthra-quinones.Part VII. By WILLIAM BERTRAM MILLEB and ARTHUR GEORGE PER~IN . CCCLXVIII.-Studiea with the Microbalance. Part II. The Photochemical Decomposition of Silver Chloride. By ERNEST JOHANNES HARTTJNU . . . CCCLXIX.-Absorp$ion Spectra and Lactam-btim Tauto-merism. By RECHARD ALAN MORTON and EDWABD ROGER^ tXCLXX.-TxypanocU Action and Chemical Cadtution. Part IU. Arainic Acids containing the G€yoxaliss Nucleus. By ISIDOBE ETXANAE BAIABAN and EAROLD KING . . CCCLXN.-me Preparation of Tertiary Arsines PAGE 2602 2605 261 1 2625 2632 2651 2660 2667 2671 2677 2684 2691 2698 270 CONTENTS. CCCLXXI.-The Rate of Reaction of Bromine with Aqueous Formic Acid. By DALZIEL LLEWEI;LYN m a , WILLCAM KBNXETH HUTCHISON and EELEDEBICK Row-C X X X X I I .- h t o n i c Estem derived from Phenacyl Bromide by Condensation with Ethyl Sodiomalomte and Andogons Substances. By RAMONI M o m RAY and J ~ " D B A NATEI RAY . CCCLXXIII.-Equilibrium in the Sptem CwCO*O.C&+ H,OeCWOH + CH,*CO.OH. By GEORGE JOSEPH B o ~ ~ o w s . . 0 CCCLXXIV.-Spth& of 2 3 5 (or 2 3 4)-Trimethyl Glucose. By JAMES C ~ L Q U H O ~ ~ IRVINE and JOHN WAZTEB HYDE OLDHAM . CCCTlxV.-Glycerol Glucoside. By HELEN SIMPSON GILCHRIST and CLIP~~ORD BUZBOUGH PrraVEs NoTEs.-&dphomtion of Pchlorophenol. By JOHN MIL-DRED GAUNTLETF and SAMUEL Smms . 2-m-Xylidino-5-ethoxy-4 &i-dihydrothhzole. By VLSH-VANATH KEKSEINA NIIKKAR and ~ A X K LEE PYXAH . CCCLXXVI.-The Heat of Combustion of Salicylic Acid.By ENDRE BEBNEB . CCZLXXVIC.-UnRtable States of Solutions of Sodim Behenate. By MARY EVELYN LAING . cCCLXXvrrZ.-SUlphur Compounds Removed from a Persian Petroleum by Means of Sulphuric Acid. Part I. By EDWARD HEXBY T H I E ~ Y . CCCLXXTX.-Co&nsatiom of the Sodium Derivatives of Trimethylene Glycol and Glycerol. By ARTHUR FAIB-BOURNE and GRAHAM EDWAED FOSTER CCCLXXX.-The Formation aad Growth of Silver Nuclei in the Decomposition of Silver 0At.e. By JAMES YOUKGEB MACDONALD and CYRIL NORMAN HINSHEL-CCCLXXXI.-The Influence of Different Nuclei on the Absorption Spectra of Substanceg. By JOHN EDWARD P U R V I S . CCCLXXXII.-The Possible Enhanced -4ctivity of Eewly-formed Molecules. By FRANK ROBERT Goss and CHRISTOPHER KELE INGOLD . . Part I.By JOHN READ and ALISON MABY RITCHIE COOE . LANDSON SNIELlL . . . . . . WOOD . CCCT,XXXTTT.-Researchm in the Menthone Series. Xxxi PAOP 2715 2721 2723 2729 2735 2745 2746 2747 2751 2756 2759 2764 2771 2776 278 xxxii CONTENTS. PA-CCCLXXXIV.-The Ionic Activit.y Product of Water in CCCLXXXV.-A Comparison of Methods of Xeasuring the By NEIL K. ADAM ROBERT S. CCCLXXXJ71.-An Electrometric and a Phase Rule Study of some Basic Salts of Copper. By HUBERT THOMAS STANLEY BRITTON . . 2796 CCCLXXXVI1.-The Relationship between the Optical Rotatory Powers and the Relative Configurations of Optically Active Compounds. Part 11. The Relative Configurations of the Optically Active Blandelic Acids and 13-Phenyl-lactic Acids.By GEORGE WILLIAM CLOUGH . . 2808 CCCLXXXVII1.-The Action of Silica on Electrolytes. Part 11. By ALFRED FRANCIS JOSEPH and HENRY BOWEN OAKLEY . . 2813 CCCLXXXIX.-Isomeric Change in -Aromatic Compounds. Part I. The Conversion of Diacylanilides into Acyl-amino-ketones. By ARTHUB WILLIAM CHAPMAN . 2818 CCCXC.-The Partial Pressures of Water Vapour and of Sulphuric Acid Vapour over Concentrated Solutions of Sulphuric Acid at High Temperatures. By JOHN SBIEATH THOBUS and WILLL~M FRANCIS BARKER . 2820 CCCXC1.-The Partial Formaldehyde Vapour Pressures of Aqueous Solutions of Formaldehyde. Part II. By WILFRID LEDBURY and ETHELBERT B 7 n ; ~ BLAIR . 2832 CCCXCII.-?hansformations of the Sugar Nitrates. By CCCzZCIII.-Lead Dihydride and Lead Tetrahydride. By EDWARD JOSEPH WEEKS .. 2845 CCCXCIV.-Complex Formation in Lead Nitrate Solutions. Part II. The Quaternary System Potassium Nitrate-Lead Nitrate-Barium Nitrate-Water. By SAMUEL GLASSTONE and ERNEST J. RICGS . . 2846 CCCXCV.-The Behaviour of Glucose and Certain Other Carbohydrates towards Dyestuffs and towards Potassium Ferricyanide in an Alkaline Medium. By EDMUND KNECHT and EVA HIBBERT . . 2854 CCCXCIVI.-The Salting-out Effect. The Influence of Electrolytes on the Solubility of Iodine in Water. By JOHN STANLEY CARTER . . 2861 CCCXCVII.-The Partial Pressures of Aqueous Ethyl Alcohol. By &,YARD JOHN EGLINTON DOBSON . 2866 Glycerol-Water Mixtures. By JAMES COLVIN . . 2788 Polarity of Surfaces. MORRELL and RONALD G. W. NORRJSH . . 2793 Jom- WALTER HYDE OLDHAM . . 284 coxam!?Ts. KKKcii P A W CiXXCVIII.-!L'he Methylation of the Oximes of B e d . By OSCAR L. BRADY and HILDA M. PERRY ccCXCIX.-Studies of Dynamic Isomerism. Part XX. Amphoteric Solvents aa Catalysts for the Mutarohtion of the Sugars. By THOMAS i k l ~ ~ r n LOWRY and CCCC.-Reactions of Organic Thidphates. By HENBY BELL FOOTNEB and SAMUEL S m s . CZCCI.-Observations on the Claisen Reaction. By GILBERT T. MORGAN and EUSEB~S Horns . CCCCII.-The Relation of Homogeneous to Catalysed Reactions. The Catalytic Decomposition of Hydrogen Iodide on the Surface of Platinum. By Cyan; N o w HINSHELWOOD and ROBERT EMME!LT Boag. CCCC1II.-Oxidation of Ethyl Ether to Oxalic Acid in Presence of Uranyl Nitrate. By SYDNEY WIILLIBM ROWELL and ALEXAXDER SMITH RUSSELL CCCCIV.-Polymerisation of p-Glucosan. The Constitution of Synthetic Dextrins. By JABEES COLQUHOUN IRVINE and JOHN WALTER HYDE OLDHAM . c(x3Cv.The Electrical Conductivities of Hydrogen Chloride and Potassium Chloride in Water and Acetone-Water Mixtures. By T~;OMAS KERFOOT BROWS-ON and cCCCVI.-The Velocity of Decomposition of Heterocyclic Diazonium Salts. Part I. Diazonium S a h of the Pyrazole and Pyrazolone Series. By JOSEPH REILLY and DENI~ MADDEN ccccvII.-The SwelIing and Dispersion of Some Colloidal Snbsfa;nces in Ether-Alcohol Mixfures. By ERNEST ccIccvITI.-The Allotropy of Zinc. By DAVID STOCKDALE CCCCIX.-Electrometric Study of the Reactions between Alkalie and Silver Nitrate Solutions. By HUBERT !ho&us STANLEY BIWITOX . Noms.-Prepamtion of p-Bromophenylhydroxylamine by the Emulsiiication Process. A Modification. By ROBERT DOWNS HAWOBTH and BBTHVR LAPWORTH . Action of Hydrazine Hydrate on Phenanthmquinone. A Correction. By SIKHIBHIJSHAH Dun . m e Aluminioxalata of Bome Optically Active Bases. By THOMAS BRUCE CHILD ELWYN ROBERTS and EUSTACE EBENEZEBTWNEB. . h K I X E J O H N F A U " E B . . FRANK MAURICE &4Y . wAL'J!ERJOHh'1MBB\DLES . OBITIJABY NOTICES 2 " 2874 2883 2887 2891 2896 2900 2903 2923 2936 2940 2951 2956 2970 2971 2971 297 INFORMATION FOR AUTHORS. THE names of new compounds should be italichd (underlined in the typescript) and the results of d y s i s given in the form : (Found C 43-2; H 6.5; N 11-3; My cryoscopic in benzene 276 255. C,H,,O,N requires C 43.5; Only in special cases should full analytical data be recorded. H 6-4 ; N 1103% ; Af 248). For known compounds the results of analysis should (Found C 50-1 ; H 11.1 ; N 39.1. Calc. C 50.0 ; In giving references to other work the journal (abbreviated title) the year the volume and the page should be given in the text in the order shown; e.g. J . pr. Chem. 1905 71 260. The official list of abbreviated titles is given at the end of the Annual Index of Abstracts. be given in the form : H 11.1 ; N 3809%)

ISSN:0368-1645    

DOI:10.1039/CT92527FP001

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

4 MYERS AND JONES : 11.-A Fractionating Column with Moving Parts. By JAMES ECKERSLEY MYERS and WIUTAM JACOB JONES. CONSIDERABLE attention has been paid to the improvement of the fractionating column and to the question of its efficiency. The matter is fully treated in “ Distillation Principles and Processes ” by Sydney Young (London 1922) and in the “Symposium on * It has sometimes been observed that the catalyst appeared to have lost its catalytic activity after it had been subjected for a moment to contact with a reacting mixture contaminated with certain interfering gases as in the case for example of contamination by hydrogen phosphide. Here we must admit that the interfering gas has caused the formation (by oxidation or by condensation or by reaction on the catalyst) of substances of small volatility which remain fixed on the surface of the catalyst and must be destroyed in order that the cat,alytic activity (regeneration of the catalyst) may reappear.These substances then play the part of antioxygenes in accordance with the general mechanism explained above I A FRACTIONATING COLUMN WITH MOVING PSRTS . 3 Distillation ” ( J . Isad. Eng. (?hem. 1922 14 476497). However, the columns therein described are of the usual type with stationary parts and it was suggested to the authors by Professor Arthur Lapworth F.R.S. that it would be of interest t o construct a frac-tionating column with moving parts and to compare its performance with those of fractionating columns of the usual type. I n the perfect fractionating column equilibrium between vapour and liquid would be attained a t each point or in each section.For such an arrangement a necessary condition would be perfect contact between vapour and liquid a t each point or in each section throughout the column. The more nearly this is approached in real practice the greater will be the efficiency. I n order to attain this agitation of the vapour and a continuous fine dispersion of the liquid in each section of the column would be helpful provided, of course that the energy consumed in effecting these two operations was not excessive. I n the case of an upright column of cylindrical or conical form and consisting of several sections the mechanically simplest way to effect fine dispersion of the liquid in each section is to provide the column with a central vertical revolving shaft which within each section carries iL horizontal and centrally-placed disk or cup the function of the revolving disk or cup being to receive the liquid falling from the next higher section and by centrifugal action to impel i t either in the form of fine drops or as a t’hin film through the section.I n its flight the liquid comes into intimate contact with the ascending vapour in the section. After its flight the liquid falls in contact with the wall of the section and finally when i t arrives a t the aperture in the bottom of the section drops down on to the revolving disk in tlhe next lower section where the process above described is repeated. I n order to secure the greatest efficiency the duration of free flight shciuld be considerable compared with the time occupied in falling in contact with the wall and for this reason a cup form of impeller would in general be preferable to a disk one, as the former would give an initially upwardly-directed flight with a consequently lengthier trajectory for a given free horizontal raiigc.However in practice with the Forms and dimensions of column and a t the specds of revolution which we have employed, we have found no advantage in the use of a cup form over a disk one. In this connexion i t appears that i t is neither the exact shape of the disk nor the speed of revolution of the shaft that matters so much as the peripheral velocity of thc disks. Therefore by using disks of greater diameter the same effect could be attained with a diminished speed of revolution of the shaft and this would be a considerable engineering and economic consideration in th 6 MYERS AND JONES: practical employment of a rotary column but in any case an adequate period of free flight must be given to the liquid.Agitation of the vapour in each section could be effected by means of propeller blades of suitable form and dimensions fixed to the ahaft and placed below the disk. In the experiments described below however we have not employed such a vapour-agitating device. We have designed a fractionating column on the lines described in the FIG. 1. p y 7cHAMBERE SnLtHEAD. foregoing. The column a skilful piece of work by Mr. Stelfox of Manchester, was constructed of tinned copper and was cylindrical in form 32-5-cm.high and 7.5 cm. in diameter. It was divided into seven sections by downwardly-directed conical trays A which were equally vertically spaced a t 3.5 cm. and the centres of which were circular horizontal apertures B 1-25 cm. in diameter. A shaft C made of thin iron rod passed centrally through the aper-tures and at its end a t the bottom of the column worked on a bearing which was fixed to the column. Within each section the shaft carried a thin copper horizontal disk D 2.5 cm. in diameter. In order to secure the best working it is important that both column and shaft should be accurately vertically orientated. The shaft emerged out of the highest section by a fairly tightly stuffed passage and above it carried The highest section of the column was provided a driving pulley.with a side exit-tube for the vapour and near by was a thermometer to register the temperature of the escaping vapour. The whole column was protected from draught by an asbestos sheet. In an experiment the liquid mixture to be fractionally distilled was contained in a copper boiling flask which was attached by means of a cork to the bottom of the column. The driving pulley was attached to a motor and to a tachometer. The vapour issuing out of the exit-tube was condensed collected in a receiver and thereafter examined. Throughout all our trials a constant rate of collection of distillate was maintained the heating being so con-trolled that about one drop of distillate fell per second into th A FRACTIOSATING COLUMN WITH MOVING PARTS.7 receiver. I n our experiments the atmospheric pressure was suffi-ciently near normal to obviate any correction of boiling points on that account. By conducting our distillations under the described conditions we were enabled directly to compare the results obtained with our column with those obtained with other columiis on identical mixtures a t the same rate of distillation. I n each experiment, 200 C.C. of mixture were used. I n the tables the following abbrevia-tions are used. F T stands for the final temperature of the fraction V for the volume of the fraction in c.c. V/D for the volume of the fraction per degree T V for the total volume of distillate and R for the number of revolutions of the shaft per minute. Experiment A.The sisted of equal parts benzene and toluene. FT. V. VID. 82" 41 22-8 84 40 20.0 86 8 4.0 88 7 3.5 100 13 1.1 10s 12 1.5 110 42 21.0 mixture con-by volume of TV. R. 41 1100 81 1100 s9 1200 96 1400 109 1400 121 1500 163 1500 Experiment B. The mixture con-sisted of equal parts by volume of benzene and toluene. V. V/D. TV. R. 81.0 45.0 81.0 1600 4.5 2.3 85.5 2400 6.0 3.0 91.5 2400 3.0 1.5 94.5 2400 6.5 0.5 101.0 2400 10.0 1.3 111.0 2400 20.0 10-0 131.0 2400 Comparison of these two experiments shows the effect which an increased speed of rotation and therefore finer dispersion of the liquid in the column has on the completeness of the separation into the constituents. Experiment C . 101 C.C. of water.The mixture distiIled contained 99 C.C. of ethyl alcohol and R = 100. FT. V. VID. TV. FT. V. V/D. TV. 79" 89 141.4 99 97" 1 0.1 106 811 3 3.0 102 99.8 3 1.0 109 s7 3 0.4 105 In experiment C the first fraction contained 94% by volume of alcohol and thus of the 99 C.C. of alcohol originally taken 93 C.C. were recovered in the first fraction in one distillation. 111 order to afford a comparison between the performance of the rotary column and other standard forms we have drawn up the following table in which are given data concerning the fractional distillation of 200 C.C. of a mixture of equal parts of benzene and toluene the distillate being collected a t the rate of a drop per second. Under the name of each column is given corresponding t o each fraction the value of V/D namely the volume of the frac-tion in C.C.divided by its temperature-interval in degrees. The most efficient column is that which gives the highest value to V/ 8 A FRACTIONATING COLUMN WITH MOVING PARTS. in the immediate neighbourhood of the boiling points of the pure constituents and the lowest value elsewhere. Final Temp. of Fraction. 82 O 84 86 88 100 108 110 Hempel Column. 58 cm. 15.6 12.0 9.0 6.0 2.0 2.0 7.0 Y o u n g 8-section Evaporator Column. 78 em. 25.6 15.0 4.0 2.0 2.6 0-8 3.6 Rotary 7 -section Column at 2400 Revs. 32-5 cm. 46.0 2.3 3-0 1-5 0.5 1.2 10.0 Y o u n g 13 -section Evaporator Column. 131 cm. 45.8 1.6 1.2 1.0 0.4 0.4 2.4 As will be seen from the above the rotary column performed satisfactorily.Another point in its favour is that during the dis-tillation it held a smaller mass of liquid and vapour than any of the other forms. Owing to the complexity of the factors involved and to our incomplete knowledge of them it is impossible to give exact direc-tions for determining the real economic efficiency of any type of fractionating column except by direct trials. The best that one can do in the case of a new type is to compare its performance with that of a standard efficient type paying attention to complete-ness of separation of the constituents of the mixture with which i t has to deal and to its initial and running costs. No claim is here made that we have established the best form dimension, or revolution speed for a rotary column nor in view of our experi-ence of the diverse behaviours of different mixtures do we consider that such could be satisfactorily determined except by direct trials with the particular mixture that is to be resolved by distillation into its constituents.However sufficient evidence has been adduced to demonstrate that the principle of the fractionating column with moving parts introduces a useful innovation and one that might in certain cases be advantageously adopted in practice. We are at present designing a new model which it is hoped will be more efficient than the one here described. We desire to thank Professor Lapwort,h for his suggestion and THE UNIVERSITY MANCHESTER. for his interest in the work.UNIVERSITY COLLEGE CARDIFF. [Received October loth 1924. 4 MYERS AND JONES : 11.-A Fractionating Column with Moving Parts. By JAMES ECKERSLEY MYERS and WIUTAM JACOB JONES. CONSIDERABLE attention has been paid to the improvement of the fractionating column and to the question of its efficiency. The matter is fully treated in “ Distillation Principles and Processes ” by Sydney Young (London 1922) and in the “Symposium on * It has sometimes been observed that the catalyst appeared to have lost its catalytic activity after it had been subjected for a moment to contact with a reacting mixture contaminated with certain interfering gases as in the case for example of contamination by hydrogen phosphide. Here we must admit that the interfering gas has caused the formation (by oxidation or by condensation or by reaction on the catalyst) of substances of small volatility which remain fixed on the surface of the catalyst and must be destroyed in order that the cat,alytic activity (regeneration of the catalyst) may reappear.These substances then play the part of antioxygenes in accordance with the general mechanism explained above I A FRACTIONATING COLUMN WITH MOVING PSRTS . 3 Distillation ” ( J . Isad. Eng. (?hem. 1922 14 476497). However, the columns therein described are of the usual type with stationary parts and it was suggested to the authors by Professor Arthur Lapworth F.R.S. that it would be of interest t o construct a frac-tionating column with moving parts and to compare its performance with those of fractionating columns of the usual type.I n the perfect fractionating column equilibrium between vapour and liquid would be attained a t each point or in each section. For such an arrangement a necessary condition would be perfect contact between vapour and liquid a t each point or in each section throughout the column. The more nearly this is approached in real practice the greater will be the efficiency. I n order to attain this agitation of the vapour and a continuous fine dispersion of the liquid in each section of the column would be helpful provided, of course that the energy consumed in effecting these two operations was not excessive. I n the case of an upright column of cylindrical or conical form and consisting of several sections the mechanically simplest way to effect fine dispersion of the liquid in each section is to provide the column with a central vertical revolving shaft which within each section carries iL horizontal and centrally-placed disk or cup the function of the revolving disk or cup being to receive the liquid falling from the next higher section and by centrifugal action to impel i t either in the form of fine drops or as a t’hin film through the section.I n its flight the liquid comes into intimate contact with the ascending vapour in the section. After its flight the liquid falls in contact with the wall of the section and finally when i t arrives a t the aperture in the bottom of the section drops down on to the revolving disk in tlhe next lower section where the process above described is repeated.I n order to secure the greatest efficiency the duration of free flight shciuld be considerable compared with the time occupied in falling in contact with the wall and for this reason a cup form of impeller would in general be preferable to a disk one, as the former would give an initially upwardly-directed flight with a consequently lengthier trajectory for a given free horizontal raiigc. However in practice with the Forms and dimensions of column and a t the specds of revolution which we have employed, we have found no advantage in the use of a cup form over a disk one. In this connexion i t appears that i t is neither the exact shape of the disk nor the speed of revolution of the shaft that matters so much as the peripheral velocity of thc disks.Therefore by using disks of greater diameter the same effect could be attained with a diminished speed of revolution of the shaft and this would be a considerable engineering and economic consideration in th 6 MYERS AND JONES: practical employment of a rotary column but in any case an adequate period of free flight must be given to the liquid. Agitation of the vapour in each section could be effected by means of propeller blades of suitable form and dimensions fixed to the ahaft and placed below the disk. In the experiments described below however we have not employed such a vapour-agitating device. We have designed a fractionating column on the lines described in the FIG. 1. p y 7cHAMBERE SnLtHEAD. foregoing. The column a skilful piece of work by Mr.Stelfox of Manchester, was constructed of tinned copper and was cylindrical in form 32-5-cm. high and 7.5 cm. in diameter. It was divided into seven sections by downwardly-directed conical trays A which were equally vertically spaced a t 3.5 cm. and the centres of which were circular horizontal apertures B 1-25 cm. in diameter. A shaft C made of thin iron rod passed centrally through the aper-tures and at its end a t the bottom of the column worked on a bearing which was fixed to the column. Within each section the shaft carried a thin copper horizontal disk D 2.5 cm. in diameter. In order to secure the best working it is important that both column and shaft should be accurately vertically orientated. The shaft emerged out of the highest section by a fairly tightly stuffed passage and above it carried The highest section of the column was provided a driving pulley.with a side exit-tube for the vapour and near by was a thermometer to register the temperature of the escaping vapour. The whole column was protected from draught by an asbestos sheet. In an experiment the liquid mixture to be fractionally distilled was contained in a copper boiling flask which was attached by means of a cork to the bottom of the column. The driving pulley was attached to a motor and to a tachometer. The vapour issuing out of the exit-tube was condensed collected in a receiver and thereafter examined. Throughout all our trials a constant rate of collection of distillate was maintained the heating being so con-trolled that about one drop of distillate fell per second into th A FRACTIOSATING COLUMN WITH MOVING PARTS.7 receiver. I n our experiments the atmospheric pressure was suffi-ciently near normal to obviate any correction of boiling points on that account. By conducting our distillations under the described conditions we were enabled directly to compare the results obtained with our column with those obtained with other columiis on identical mixtures a t the same rate of distillation. I n each experiment, 200 C.C. of mixture were used. I n the tables the following abbrevia-tions are used. F T stands for the final temperature of the fraction V for the volume of the fraction in c.c. V/D for the volume of the fraction per degree T V for the total volume of distillate and R for the number of revolutions of the shaft per minute.Experiment A. The sisted of equal parts benzene and toluene. FT. V. VID. 82" 41 22-8 84 40 20.0 86 8 4.0 88 7 3.5 100 13 1.1 10s 12 1.5 110 42 21.0 mixture con-by volume of TV. R. 41 1100 81 1100 s9 1200 96 1400 109 1400 121 1500 163 1500 Experiment B. The mixture con-sisted of equal parts by volume of benzene and toluene. V. V/D. TV. R. 81.0 45.0 81.0 1600 4.5 2.3 85.5 2400 6.0 3.0 91.5 2400 3.0 1.5 94.5 2400 6.5 0.5 101.0 2400 10.0 1.3 111.0 2400 20.0 10-0 131.0 2400 Comparison of these two experiments shows the effect which an increased speed of rotation and therefore finer dispersion of the liquid in the column has on the completeness of the separation into the constituents.Experiment C . 101 C.C. of water. The mixture distiIled contained 99 C.C. of ethyl alcohol and R = 100. FT. V. VID. TV. FT. V. V/D. TV. 79" 89 141.4 99 97" 1 0.1 106 811 3 3.0 102 99.8 3 1.0 109 s7 3 0.4 105 In experiment C the first fraction contained 94% by volume of alcohol and thus of the 99 C.C. of alcohol originally taken 93 C.C. were recovered in the first fraction in one distillation. 111 order to afford a comparison between the performance of the rotary column and other standard forms we have drawn up the following table in which are given data concerning the fractional distillation of 200 C.C. of a mixture of equal parts of benzene and toluene the distillate being collected a t the rate of a drop per second.Under the name of each column is given corresponding t o each fraction the value of V/D namely the volume of the frac-tion in C.C. divided by its temperature-interval in degrees. The most efficient column is that which gives the highest value to V/ 8 A FRACTIONATING COLUMN WITH MOVING PARTS. in the immediate neighbourhood of the boiling points of the pure constituents and the lowest value elsewhere. Final Temp. of Fraction. 82 O 84 86 88 100 108 110 Hempel Column. 58 cm. 15.6 12.0 9.0 6.0 2.0 2.0 7.0 Y o u n g 8-section Evaporator Column. 78 em. 25.6 15.0 4.0 2.0 2.6 0-8 3.6 Rotary 7 -section Column at 2400 Revs. 32-5 cm. 46.0 2.3 3-0 1-5 0.5 1.2 10.0 Y o u n g 13 -section Evaporator Column.131 cm. 45.8 1.6 1.2 1.0 0.4 0.4 2.4 As will be seen from the above the rotary column performed satisfactorily. Another point in its favour is that during the dis-tillation it held a smaller mass of liquid and vapour than any of the other forms. Owing to the complexity of the factors involved and to our incomplete knowledge of them it is impossible to give exact direc-tions for determining the real economic efficiency of any type of fractionating column except by direct trials. The best that one can do in the case of a new type is to compare its performance with that of a standard efficient type paying attention to complete-ness of separation of the constituents of the mixture with which i t has to deal and to its initial and running costs. No claim is here made that we have established the best form dimension, or revolution speed for a rotary column nor in view of our experi-ence of the diverse behaviours of different mixtures do we consider that such could be satisfactorily determined except by direct trials with the particular mixture that is to be resolved by distillation into its constituents. However sufficient evidence has been adduced to demonstrate that the principle of the fractionating column with moving parts introduces a useful innovation and one that might in certain cases be advantageously adopted in practice. We are at present designing a new model which it is hoped will be more efficient than the one here described. We desire to thank Professor Lapwort,h for his suggestion and THE UNIVERSITY MANCHESTER. for his interest in the work. UNIVERSITY COLLEGE CARDIFF. [Received October loth 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700004

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

THE ABSORPTION SPECTRA OF VARIOUS ALDEHYDES ETC. 9 111.-The Absorption Spectra of Various Aldehydes and Ketones and some of theiy Derived Compounds. By JOHN EDWARD PURVIS. THE aim of this communication is to discuss the results observed in the following compounds formaldehyde paraldehyde trithio-formaldehyde a-trithioacetaldehyde p-trithiobenzaldehyde cr-di-phenylglyoxime diacetylmonoxime acetal methylal benzylidene-acetone benzylideneacetophenone benzylideneacetoxime benzyl-idenedeoxybenzoin benzylidenecamphor cinnamylidenecamphor. The methods of investigation have been described before. In 1912 the author and McCleland (J. 101 1810) and Bielecki and Henri (Ber. 45 2819) investigated the absorption bands of various aliphatic aldehydes and ketones. Among these solutions of form-aldehyde in alcohol and in ether showed no selective absorption.The following substances exhibit no specific absorption in solu-tion. The concentration of the solution and the name of the solvent are given and also the positions of the rays from a condensed cadmium spark that were transmitted through varying thicknesses of the solut'ion increasing by 2 mm. for each photograph (only the first and the last value are given in each case) Formaldehyde, 30% in water; 10 mm. 3250; 90 mm. A 2930. Paraldehyde. 2111 in ethyl alcohol; 12 nim. A 2150; 90 mm. A 2560. Trithio-formaldehyde M/550 (the highest obtainable) in ethyl alcohol ; 20 mm. A 2560; GO mm. A 2680; X/5500; 20 mm. A 2160; 60 mm. A 2270. a-Trithioncetaldehyde N / l O in alcohol; 10 mm., ?,3650; 30 mm.1,2750; MllOO; 10 mm. 12500; 30 mm., ? 2600; MjlOOO; 10 mm. A 2180; 30 mm. A 2350. p-Trithio-bewaldehyde J1/1350 (the highest obtainable) in alcohol ; 20 mm., A 2570; GO mm. A 2750; M/13,500; 20 mm. A 2290; 60 mm., A 2450. fMethyZal 2111 in alcohol; 10 mm. 1,2100; 80 mm., ? 3190. Acetal 2M in alcohol; 20 mm. A 2550; 76 mm. A 2750; M ; 10 mm. 12450; 62mm. 1,2570; M/10; 10 mm. 2310; 62 mm. A 2470 ; M/100; 12 mm. A 2120; 56 mm. A 2270. Purvis and McCleland showed (loc. cit.) that tlhe vapour of form-aldehyde exhibited a coizsidcrable number of narrow bands. Acet-aldehyde has a solution band a t 1/? 3500 (A 2856) and one large vapour band; chloral has a solution band a t l / A 3430 ( A 2912) and chloral hydrate has no band the solution being very transparent to the cadmium rays.To explain these phenomena it is suggested that formaldehyde unites with the solvent forming a compound whose formula might be represented as HCH(OH) and is thus comparable with CCl,.CH(OH),. Again if the formula of paralde-B 10 PURVIS THE ABSORPTION SPECTRA OF hyde which shows no absorption band is written as (A) it may be suggested that a similar type of condensation occurs with formaldehyde and its constitution could be described as (B) and this again would explain the absence of specific absorption. The solution of p-trithiobenzaldehyde showed there was no trace of the two solution bands of benzaldehyde described by Purvis and McCleland (J. 1913 103 1088); and in this respect it is com-parable with trithioformaldehyde described above.The absence of any selective absorption in solutions of methylal and acetal may be explained by a consideration of their constitutional formulze H*CH( OCH,) and CH,*CH( O*C,H,),. The aldehydic oxygen is fully saturated and there is no centre of vibration to give specific absorption. a-DiphenyZgZyoxirne.-The substance is not very soluble in alcohol and the strongest solution available was M/1700. There appeared to be a very weak band at about 12380 corresponding to the very weak band of liquid diphenyl a t A2300 described by Baly and Tryhorn (J, 1915 107 1058). The following numbers represent some of the observations made between 20 mm. and 60 mm. thickness increasing by 2 mm. for each exposure. M/1700. Thickness (mm.) ... 20 60 M/17,000. Thickness (mm.) ...20 32 40 50 60 Rays transmitted to A 2750 2900 Rays transmitted to A 2150 2270 2400 * 2550 2590 The weak band lies between A 2400-h 2270 in this solution. * The stronger Cd lines round about A 2300 were just visible. Two solution bands of benzil are described by Baly and Stewart (J. 1906 89 502) a t 1 / ~ 3900 (A 2563) and 1/A 2650 ( A 3773) and Hantzsch and Schweite (Ber. 1916,49,213) describe a similar curve. Hantzsch (Ber. 1910 43 1651) found no definite band in syn-benzilmonoxime although the line of absorption is bent a little in the region of 1 / ~ 2800-1/A 32.50 (A 3569-1 3075) and also in the region of 1 / ~ 4000 (A 2498). The two benzil bands have com-pletely disappeared in the glyoxime. The author can confirm the absence of selective absorption in diacetyldioxime first noticed by Baly and Stewart (J.1906 59 502). Solutions of strengths varying from M/10 to M/10,000 of diacetyl-monoxime were also examined but no definite bands were noticed. The general absorption was fairly strong for through 30 mm. of a M/10-solution the rays were absorbed from about A 3850 ; throug VARIOUS ALDEH-YDES AND KETONES ETC. 11 30 mm. of a M/lOO-solution from about A 3370; and through 30 mm. of a H / l O O O from about 12700. It is clear therefore that a-diphenylglyoxime behaves like all oximes in this respect. In this substance the-two CO groups of benzil have been completely eliminated in the oxime and the specific absorption of the original substance has been destroyed. BenxyZideneacet0ne.-The author has repcated the observations of Baker (J.1907 91 1490) and Baly and Schaefer (J. 1908 93, 1808) and confirms the presence of a large band a t l / A 3500 ( A 2856). The author has also repeated the work on the absorption of acetone first described by Stewart and Baly (J. 1906 $9 492) and of benzaldehyde described by Purvis and McCleland (J. 1913 103, 1088). The absorption curves of these substances have been drawn (Fig. 1) for comparison with that of benzylideneacetoiie. The band of the latter substance is narrower than the acetone band, and the two benzaldehyde bands have disappeared. The vapour of benzylideneacetone was examined in a 200-mm. tube a t various temperatures and pressures with the following results : Pressure in mm. ,770 A . 60 792 60 802 T O 812 80 822 90 832 100 84 2 The rays were transmitted to h 2120.Tfie rays were weak between h 2780 and h 2420 and then transmitted to about h 2120. The rays were almost completely absorbcd between A 2880 and A 2400 and then transmitted to A 2150. The rays were completely absorbed between h 2950 and A 2360 and then transmitted to h 2200. The rays were absorbed from A 3000 but the series of Cd lines round about h 2300 was visible. The rays were absorbed from h 3010 the Cd lines at h 2300 being very faint,. Similar results were obtained when t,he vapour was examined a t a constant pressure of 757 mm. and a t temperatures varying from 40-80". The radiations of a Welsbach light were used to investigate the more refrangible regions of the visible spectrum.No absorption bands were recorded and the rays were transmitted to about 13200 i.e. as far as the radiation affected the photo-graphic plate. All these experiments prove that the narrow vapour bands of benzaldehytle described by Purvis and McCleland (Eoc. cit.) have disappeared. These authors also proved (Zoc. cit.) that acetone had no narrow vapour bands. The results appear to indicate that the different unsaturated vibratory centres do not act independently of each other. I n this direction the author has pointed out (J. 1914 105 2482) that the solution and vapour of benzylidene chloride possess the residues of three benzene solu-tion bands (comparable with the three toluene bands) and that B* 12 PURVIS THE ABSORPTION SPECTRA OF benzaldoxime has several of these residual bands bordering on a stronger band.The elimination of the oxygen of the CO group in both cases enables the molecule to recover some portion of the vibrations of the original benzene ring. It was also shown (Zoc. cit.) that cinnamaldehyde had one large band covering the area occupied by the two benzaldehyde bands and Ohat through 30 mm. of a M/10-solution the former substance absorbed the rays from A 3940 i.e. within the areas of the visible spectrum. Now in benzylideneacetone the two benzaldehyde bands dis-appear and the larger single band is not unlike the acetone band. Also through 30 mm. of a M/10-solution the substance absorbed the rays from about A 3850 i.e. within the borders of the visible region. There is no exhibition of any residual benzene bands noted in benzylidene chloride and benzaldoxime.It is apparent, therefore that the vibrations of the three unsaturated centres of benzylideneacetone do not act independently. Their interacting oscillations produce great absorption and the development of a weak colour. Cinnamylideneacetone has a large band at about 1 / A 3200 (A 3120) according to Baly and Schaefer (J. 1908 93 1808); and at the greatest thickness the line of absorption appears to be at about A 3815 i.e. a t the edge of the more refrangible region of the visible spectrum. This large band is not unlike that of benzylideneacetone. BenzyZideneacet0xime.-Alcoholic solutions of this colourless substance were examined and the curve was drawn (Fig. 1). Com-paring this case with benzylideneacetone it is evident that the colour of the latter depends chiefly on the CO group.In the oxime the line of general absorption and the band are shifted more towards the more refrangible regions. The band is a little wider and less persistent and the substance less transparent in the more refrangible regions. The line of general absorption through 30 mm. of a M/10-solution is at A 3500 and in benzylideneacetone it is at A 3850. BenxyZidenedeoxybenxoin.-Solutions of this substance were examined and the curve (Fig. 2) shows one very shallow band, the line of general absorption rapidly extending into the visible regions. The line of general absorption through 30 mm. of a M/lOO-solution was at 13930. Stobbe -and Ebert (Ber. 1911, c44 1289) describe a large band in benzylideneacetophenone.The author has repeated the observations and drawn the curve for comparison. The band is wider than that of benzylideneacetone and is shifted more towards the red end. CinnamyZidenecampho~.-Lowry and Southgate (J. 1910 97 VARIOUS ALDEHYDES AND KETONES ETC. 13 905) describe a solution band of benzylidenecamphor a t about 1 / A 3450 (a 2896). The author has repeated these observations, to compare the phenomena with those exhibited by cinnamylidene-camphor (Fig. 2 ) . The differences are the greater shift of the absorption of thc latter towards the red the lessened transparency of the cinnamylidene compound in the more refrangible regions, and the wider band. The chief effect seems to be that the additional unsaturated centre has strengthened the colour and shifted the band more towards the red.The line of absorption through 30 mm. of M/10-solution is a t A 3960 in benzylidenecarnphor and at h 4250 in cinnamylidenecamphor . FIG. 1. Oscillation frequencies. 1 \ 1 I I I 1 I I I 1 30mm. 3f FIG. 2. 27 31 35 39 43 Oscillation frequencies. 39mm. 2 NjlO 2 c s 61/100 2 30mm. 2 + .o 30mm. M/l00O y 30mm. * * u - u Jf / 10,000 I Benzylideneacetone ; I1 Benzyl- I Benzylidenecamphor (dash) ; I1 Ginnamyl-ideneacetoxime ; III BenzaLdehyde idenecanaphor ; ILI Benzylidenedeoxybenzoin (dagh) ; IV Aceione. (dot and dash) ; IV Benzylideneacetopheno1:e. The outstanding results of these and earlier observations are : (1) all aldehydes and ketones exhibit selective absorption in well-defined areas of the ultra-violet region and this disappears when the aldehydic or ketonic groups are eliminated or neutralised.Examples of such phenomena are the oximes paraldehyde form-aldehyde thioaldehydes methylal acetal chloral hydrate. (2) All other substances which have unsaturated centres also show specific absorption. These centres may be ethylenic or acetylenic or both, and may also act in union with other centres such as unsaturated benzene residues ketones and aldehydes. When these oscillatory centres are successively eliminated the absorption band or bands are altered in appearance; or the specific bands characteristic o 14 WHEELER THE IGNITION OF GASES. one or other of the remaining centres are partly developed. There is also a shift of the line of general absorption and of the remaining band or bands towards the more refrangible regions.Finally, when all the oscillatory centres are completely saturated the substance shows no specific absorption and is very transparent. (3) The colour of organic substances as Dr. Armstrong pointed out long ago appears to depend largely on the substances possessing a t least three unsaturated constituents. Each centre has its own specific influence which is unlike that of the others but with which it acts in co-operation. Substances which have a t least three unsaturated centres and are coloured are benzylideneacetone, benzylideneacetophenone benzylidenedeoxybenzoin cinnamylidene-acetone cinnamylideneacetophenone benzylidenecamphor cinnam-ylidenecamphor.On the other hand diacetyl and glyoxal are coloured and they have only two centres. It is suggested that the complete action of the unsaturated centres depends on their chemical type. It can hardly be doubted for example that a ketonic or an aldehydic centre exercises more influence in specific absorption than any other. PUBLIC HEALTH CHEMICAL LABORATORY, CAMBRIDGE. [Received September lst 1924. THE ABSORPTION SPECTRA OF VARIOUS ALDEHYDES ETC. 9 111.-The Absorption Spectra of Various Aldehydes and Ketones and some of theiy Derived Compounds. By JOHN EDWARD PURVIS. THE aim of this communication is to discuss the results observed in the following compounds formaldehyde paraldehyde trithio-formaldehyde a-trithioacetaldehyde p-trithiobenzaldehyde cr-di-phenylglyoxime diacetylmonoxime acetal methylal benzylidene-acetone benzylideneacetophenone benzylideneacetoxime benzyl-idenedeoxybenzoin benzylidenecamphor cinnamylidenecamphor.The methods of investigation have been described before. In 1912 the author and McCleland (J. 101 1810) and Bielecki and Henri (Ber. 45 2819) investigated the absorption bands of various aliphatic aldehydes and ketones. Among these solutions of form-aldehyde in alcohol and in ether showed no selective absorption. The following substances exhibit no specific absorption in solu-tion. The concentration of the solution and the name of the solvent are given and also the positions of the rays from a condensed cadmium spark that were transmitted through varying thicknesses of the solut'ion increasing by 2 mm.for each photograph (only the first and the last value are given in each case) Formaldehyde, 30% in water; 10 mm. 3250; 90 mm. A 2930. Paraldehyde. 2111 in ethyl alcohol; 12 nim. A 2150; 90 mm. A 2560. Trithio-formaldehyde M/550 (the highest obtainable) in ethyl alcohol ; 20 mm. A 2560; GO mm. A 2680; X/5500; 20 mm. A 2160; 60 mm. A 2270. a-Trithioncetaldehyde N / l O in alcohol; 10 mm., ?,3650; 30 mm. 1,2750; MllOO; 10 mm. 12500; 30 mm., ? 2600; MjlOOO; 10 mm. A 2180; 30 mm. A 2350. p-Trithio-bewaldehyde J1/1350 (the highest obtainable) in alcohol ; 20 mm., A 2570; GO mm. A 2750; M/13,500; 20 mm. A 2290; 60 mm., A 2450. fMethyZal 2111 in alcohol; 10 mm. 1,2100; 80 mm., ? 3190. Acetal 2M in alcohol; 20 mm. A 2550; 76 mm.A 2750; M ; 10 mm. 12450; 62mm. 1,2570; M/10; 10 mm. 2310; 62 mm. A 2470 ; M/100; 12 mm. A 2120; 56 mm. A 2270. Purvis and McCleland showed (loc. cit.) that tlhe vapour of form-aldehyde exhibited a coizsidcrable number of narrow bands. Acet-aldehyde has a solution band a t 1/? 3500 (A 2856) and one large vapour band; chloral has a solution band a t l / A 3430 ( A 2912) and chloral hydrate has no band the solution being very transparent to the cadmium rays. To explain these phenomena it is suggested that formaldehyde unites with the solvent forming a compound whose formula might be represented as HCH(OH) and is thus comparable with CCl,.CH(OH),. Again if the formula of paralde-B 10 PURVIS THE ABSORPTION SPECTRA OF hyde which shows no absorption band is written as (A) it may be suggested that a similar type of condensation occurs with formaldehyde and its constitution could be described as (B) and this again would explain the absence of specific absorption.The solution of p-trithiobenzaldehyde showed there was no trace of the two solution bands of benzaldehyde described by Purvis and McCleland (J. 1913 103 1088); and in this respect it is com-parable with trithioformaldehyde described above. The absence of any selective absorption in solutions of methylal and acetal may be explained by a consideration of their constitutional formulze H*CH( OCH,) and CH,*CH( O*C,H,),. The aldehydic oxygen is fully saturated and there is no centre of vibration to give specific absorption. a-DiphenyZgZyoxirne.-The substance is not very soluble in alcohol and the strongest solution available was M/1700.There appeared to be a very weak band at about 12380 corresponding to the very weak band of liquid diphenyl a t A2300 described by Baly and Tryhorn (J, 1915 107 1058). The following numbers represent some of the observations made between 20 mm. and 60 mm. thickness increasing by 2 mm. for each exposure. M/1700. Thickness (mm.) ... 20 60 M/17,000. Thickness (mm.) ... 20 32 40 50 60 Rays transmitted to A 2750 2900 Rays transmitted to A 2150 2270 2400 * 2550 2590 The weak band lies between A 2400-h 2270 in this solution. * The stronger Cd lines round about A 2300 were just visible. Two solution bands of benzil are described by Baly and Stewart (J. 1906 89 502) a t 1 / ~ 3900 (A 2563) and 1/A 2650 ( A 3773) and Hantzsch and Schweite (Ber.1916,49,213) describe a similar curve. Hantzsch (Ber. 1910 43 1651) found no definite band in syn-benzilmonoxime although the line of absorption is bent a little in the region of 1 / ~ 2800-1/A 32.50 (A 3569-1 3075) and also in the region of 1 / ~ 4000 (A 2498). The two benzil bands have com-pletely disappeared in the glyoxime. The author can confirm the absence of selective absorption in diacetyldioxime first noticed by Baly and Stewart (J. 1906 59 502). Solutions of strengths varying from M/10 to M/10,000 of diacetyl-monoxime were also examined but no definite bands were noticed. The general absorption was fairly strong for through 30 mm. of a M/10-solution the rays were absorbed from about A 3850 ; throug VARIOUS ALDEH-YDES AND KETONES ETC.11 30 mm. of a M/lOO-solution from about A 3370; and through 30 mm. of a H / l O O O from about 12700. It is clear therefore that a-diphenylglyoxime behaves like all oximes in this respect. In this substance the-two CO groups of benzil have been completely eliminated in the oxime and the specific absorption of the original substance has been destroyed. BenxyZideneacet0ne.-The author has repcated the observations of Baker (J. 1907 91 1490) and Baly and Schaefer (J. 1908 93, 1808) and confirms the presence of a large band a t l / A 3500 ( A 2856). The author has also repeated the work on the absorption of acetone first described by Stewart and Baly (J. 1906 $9 492) and of benzaldehyde described by Purvis and McCleland (J.1913 103, 1088). The absorption curves of these substances have been drawn (Fig. 1) for comparison with that of benzylideneacetoiie. The band of the latter substance is narrower than the acetone band, and the two benzaldehyde bands have disappeared. The vapour of benzylideneacetone was examined in a 200-mm. tube a t various temperatures and pressures with the following results : Pressure in mm. ,770 A . 60 792 60 802 T O 812 80 822 90 832 100 84 2 The rays were transmitted to h 2120. Tfie rays were weak between h 2780 and h 2420 and then transmitted to about h 2120. The rays were almost completely absorbcd between A 2880 and A 2400 and then transmitted to A 2150. The rays were completely absorbed between h 2950 and A 2360 and then transmitted to h 2200.The rays were absorbed from A 3000 but the series of Cd lines round about h 2300 was visible. The rays were absorbed from h 3010 the Cd lines at h 2300 being very faint,. Similar results were obtained when t,he vapour was examined a t a constant pressure of 757 mm. and a t temperatures varying from 40-80". The radiations of a Welsbach light were used to investigate the more refrangible regions of the visible spectrum. No absorption bands were recorded and the rays were transmitted to about 13200 i.e. as far as the radiation affected the photo-graphic plate. All these experiments prove that the narrow vapour bands of benzaldehytle described by Purvis and McCleland (Eoc. cit.) have disappeared. These authors also proved (Zoc. cit.) that acetone had no narrow vapour bands.The results appear to indicate that the different unsaturated vibratory centres do not act independently of each other. I n this direction the author has pointed out (J. 1914 105 2482) that the solution and vapour of benzylidene chloride possess the residues of three benzene solu-tion bands (comparable with the three toluene bands) and that B* 12 PURVIS THE ABSORPTION SPECTRA OF benzaldoxime has several of these residual bands bordering on a stronger band. The elimination of the oxygen of the CO group in both cases enables the molecule to recover some portion of the vibrations of the original benzene ring. It was also shown (Zoc. cit.) that cinnamaldehyde had one large band covering the area occupied by the two benzaldehyde bands and Ohat through 30 mm.of a M/10-solution the former substance absorbed the rays from A 3940 i.e. within the areas of the visible spectrum. Now in benzylideneacetone the two benzaldehyde bands dis-appear and the larger single band is not unlike the acetone band. Also through 30 mm. of a M/10-solution the substance absorbed the rays from about A 3850 i.e. within the borders of the visible region. There is no exhibition of any residual benzene bands noted in benzylidene chloride and benzaldoxime. It is apparent, therefore that the vibrations of the three unsaturated centres of benzylideneacetone do not act independently. Their interacting oscillations produce great absorption and the development of a weak colour. Cinnamylideneacetone has a large band at about 1 / A 3200 (A 3120) according to Baly and Schaefer (J.1908 93 1808); and at the greatest thickness the line of absorption appears to be at about A 3815 i.e. a t the edge of the more refrangible region of the visible spectrum. This large band is not unlike that of benzylideneacetone. BenzyZideneacet0xime.-Alcoholic solutions of this colourless substance were examined and the curve was drawn (Fig. 1). Com-paring this case with benzylideneacetone it is evident that the colour of the latter depends chiefly on the CO group. In the oxime the line of general absorption and the band are shifted more towards the more refrangible regions. The band is a little wider and less persistent and the substance less transparent in the more refrangible regions.The line of general absorption through 30 mm. of a M/10-solution is at A 3500 and in benzylideneacetone it is at A 3850. BenxyZidenedeoxybenxoin.-Solutions of this substance were examined and the curve (Fig. 2) shows one very shallow band, the line of general absorption rapidly extending into the visible regions. The line of general absorption through 30 mm. of a M/lOO-solution was at 13930. Stobbe -and Ebert (Ber. 1911, c44 1289) describe a large band in benzylideneacetophenone. The author has repeated the observations and drawn the curve for comparison. The band is wider than that of benzylideneacetone and is shifted more towards the red end. CinnamyZidenecampho~.-Lowry and Southgate (J. 1910 97 VARIOUS ALDEHYDES AND KETONES ETC. 13 905) describe a solution band of benzylidenecamphor a t about 1 / A 3450 (a 2896).The author has repeated these observations, to compare the phenomena with those exhibited by cinnamylidene-camphor (Fig. 2 ) . The differences are the greater shift of the absorption of thc latter towards the red the lessened transparency of the cinnamylidene compound in the more refrangible regions, and the wider band. The chief effect seems to be that the additional unsaturated centre has strengthened the colour and shifted the band more towards the red. The line of absorption through 30 mm. of M/10-solution is a t A 3960 in benzylidenecarnphor and at h 4250 in cinnamylidenecamphor . FIG. 1. Oscillation frequencies. 1 \ 1 I I I 1 I I I 1 30mm. 3f FIG. 2. 27 31 35 39 43 Oscillation frequencies.39mm. 2 NjlO 2 c s 61/100 2 30mm. 2 + .o 30mm. M/l00O y 30mm. * * u - u Jf / 10,000 I Benzylideneacetone ; I1 Benzyl- I Benzylidenecamphor (dash) ; I1 Ginnamyl-ideneacetoxime ; III BenzaLdehyde idenecanaphor ; ILI Benzylidenedeoxybenzoin (dagh) ; IV Aceione. (dot and dash) ; IV Benzylideneacetopheno1:e. The outstanding results of these and earlier observations are : (1) all aldehydes and ketones exhibit selective absorption in well-defined areas of the ultra-violet region and this disappears when the aldehydic or ketonic groups are eliminated or neutralised. Examples of such phenomena are the oximes paraldehyde form-aldehyde thioaldehydes methylal acetal chloral hydrate. (2) All other substances which have unsaturated centres also show specific absorption.These centres may be ethylenic or acetylenic or both, and may also act in union with other centres such as unsaturated benzene residues ketones and aldehydes. When these oscillatory centres are successively eliminated the absorption band or bands are altered in appearance; or the specific bands characteristic o 14 WHEELER THE IGNITION OF GASES. one or other of the remaining centres are partly developed. There is also a shift of the line of general absorption and of the remaining band or bands towards the more refrangible regions. Finally, when all the oscillatory centres are completely saturated the substance shows no specific absorption and is very transparent. (3) The colour of organic substances as Dr. Armstrong pointed out long ago appears to depend largely on the substances possessing a t least three unsaturated constituents. Each centre has its own specific influence which is unlike that of the others but with which it acts in co-operation. Substances which have a t least three unsaturated centres and are coloured are benzylideneacetone, benzylideneacetophenone benzylidenedeoxybenzoin cinnamylidene-acetone cinnamylideneacetophenone benzylidenecamphor cinnam-ylidenecamphor. On the other hand diacetyl and glyoxal are coloured and they have only two centres. It is suggested that the complete action of the unsaturated centres depends on their chemical type. It can hardly be doubted for example that a ketonic or an aldehydic centre exercises more influence in specific absorption than any other. PUBLIC HEALTH CHEMICAL LABORATORY, CAMBRIDGE. [Received September lst 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700009

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

14 WHEELER THE IGNITION OF GASES. 1V.-The Ignition of Gases. Part V. Ignition by Inductance &arks. Mixtures of the Para fins with Air. By RICHARD VERNON WHEELER. ONE object of this part of the research on the ignition of gases was to compare the relative ignitibilities of mixtures of methane and air by inductance sparks (low-tension “ break-flashes ” or momentary arcs) with the values obtained when capacity sparks (high-tension impulsive discharges) were used as described in J., 1920 117 903. For as a source of ignition of gaseous mixtures, an inductance spark (produced when an electric current in an inductive circuit is interrupted by the separation of metallic con-tacts) differs from a capacity spark mainly in its longer duration, the difference being sufficiently wide to make it of importance to discover whether inductance sparks can be regarded with capacity sparks as “ momentary ” sources of heat (see J.1924 125 1858), or whether they more nearly approach in character ‘‘ sustained ” sources such as heated surfaces (see ibid. p. 1869). The character of inductance sparks is most susceptible to change PART V. IGNITION BY INDUCTION SPARKS. 15 in the conditions under which they are produced so that consider-able variation can exist in their incendivity. Fig. 1 constructed mainly from oscillograph records represents the variations with time of current resistance voltage and total heat generated in an inductance spark-gap produced by the rapid separation of metallic contacts. As the area of contact anterior to rupture of the circuit, decreases the electric resistance a t that point increases and heat is generated.Eventually the last remaining points of contact become so hot that the metal volatilises and a t the actual moment of break of circuit a conducting band of metallic vapour is pro-duced. This band rapidly increases in length as the fracture is widened until the spark can no longer be maintained. With a spark of this general character just capable of igniting a given inflammable mixture ignition most probably occurs towards the end of its duration but the precise moment depends upon the exact character of the spark as determined by the rate of increase of resistance and of decay of current in it. For these reasons, in any attempt such as is made in this research to determine the relative ignitibilities of different gaseous mix-t'ures by means of inductance sparks of different intensities we must recog-nise not only the changes measured or deduced purposely made in the intensity but also the changes in the character of the sparks.These changes FIG. 1. e m *! in character may be either inadvertent (as when the condition of the metallic surfaces that are separated changes) or a necessary concomitant of 8 change in intensity (as when the inductance of the circuit is purposely altered). In the production of inductance sparks there are six chief vari-ables which can be divided into two groups according as they relate to ( a ) electrical or ( b ) mechanical conditions. I n the former class are (1) The self-inductance of the circuit ; (2) the impressed voltage ; and (3) the current flowing in the circuit before rupture.The latter class includes (4) The nature of the metal a t the spark gap; (5) the rate of break of circuit; and (6) the area of contact a t the moment of break. Each of these variables can be more or less effectively controlled independently and the influence of each can therefore be determined. The most difficult to control and of which to gauge the influence is the last-named and most of th 16 WHEELER THE IGNITION OF GASES. experimental difficulty of this work has been in maintaining con-stancy of this factor. For with the production of a spark there is a change in the condition of the surfaces at which it passes and with a readily oxidisable metal the change may be sufficient to alter considerably the area of contact available for successive sparks as was observed when the influence of different metals at the spark gap was studied.Platinum or gold surfaces were found to be least susceptible to change and the former have been used for the majority of the experiments. Three different types of apparatus each of which had its advantages for particular series of experiments have been used. These are described in the experimental portion of this paper and are referred to as A B and C. Electrical Conditions. With an inductive circuit carrying continuous current the energy that should theoretically appear in the break-flash is the amount of energy stored electromagnetically in the system and should therefore amount to &Li2.This expression does not however, take into account losses in the circuit or absorption at the sparking-points and although it might be permissible to express the relative incendivities of sparks produced under constant circuit conditions (with a given apparatus) by their energy values it would be mislead-ing to suggest a comparison of these values with others obtained under different circuit conditions and with a different apparatus for producing the sparks. The relative ignitibilities of different gaseous mixtures are therefore expressed in this paper simply by the values of the currents (in amperes) flowing iii the circuit at the moment of interruption which yielded an inductance-spark just capable of causing ignition. (1) The Inductance of the Circuit.-A number of inductances of known magnitudes were prepared consisting of coils of silk-covered copper wire wound on cores of wood so as to be of constant value a t all currents.These were introduced into the circuit from a battery of dry cells and the current a t 90 60 and 30 volts required for the ignition of different mixtures of methane and air by a break-flash at platinum contacts was determined using apparatus A, which enabled a rapid break of circuit to be obtained. A number of the results are shown graphically in Fig. 2 in which percentages of methane are plotted against igniting-currents each curve being for a given value of inductance and impressed voltage of the circuit. From the values used in the construction of these curves the rela-tionship between the igniting current for a given mixture and the inductance of the circuit can be determined.Thus Fig. 3 shows the relationship when mixtures cont,aining 6*0,7.0 and 8.0% of methan PART V. IGNITION BY INDUCTION SPARKS. 17 were used and the impressed voltage was 90 ; additional values used for these curves are the igniting-currents when the inductance was 0.00815 henry namely 1.52 1-18 and 0.94 amp. for the 6.0 7.0, and 8.0% mixtures respectively. The relationship between the values of L of 0.008 and 0.095 henry can be expressed by the equation ,W4 = A ; that is to say the energy required in the circuit before break (+Liz) to produce the igniting sparks was nearly constant. This result is deceptive however for in other series of experiments carried out wibh a different method of producing the sparks the value +Liz was by no means constant.(In this con-METWPIE PER CENT FIG. 2. nexion see Morgan J. 1919 115 24). A simple law coiinect8ing i with L in ignition experiments could only be expected if sparks of the same charact,er could be produced wit'h different values of L, and it would appear not to be possible to vary the intensity of a spark (by varying the inductance) without altering its character ; for a t any particular instant during a break-flash when L is the inductance of the circuit T t,he resistance of the spark-gap R the resistance of the rest of the circuit and V the impressed voltage, thc value for the current is ( V - L d i / d t ) / ( r + R) whilst its limiting value a t thc outset is V/R.(2) The Impressed Voltage.-In general it can be stated that the amount of current in the circuit is of far greater importance tha 18 WHEELER THE IGNITION OF GASES. the impressed voltage as regards the igniting power of the flash produced on breaking the circuit. Especially is this so with highly self-inductive circuits. Thus an 8.0 yo methane-air mixture was ignited by the break-flash with a current of from 0.24 to 0.25. ampere under the conditions of the experiments at any voltage between 10 and 3Q the self-induction of the circuit being 0.095 henry. With higher circuit voltages however the igniting current decreases, as the results recorded in Fig. 2 show. When the contacts at which the break-flash is produced are together the voltage drop between them is zero; as soon as they are completely separated, the voltage between them is equal to the impressed voltage.During the separation of the contacts two actions are tending to make the arc between them persist namely the induced voltage which progressively diminishes and the impressed voltage which pro-gressively increases. If the impressed voltage is high i t will contribute materially to the maintenance of the arc. This effect is more marked when the rate of separation of the contacts is com-paratively slow so that the value of the induced voltage (Ldildt) is low. For example a series of experiments using apparatus B, in which massive electrodes of platinum are drawn apart slowly, gave the results shown in Table I. TABLE I. 0.095 henry.E.2I.I.P. (volts) ...... 25 40 60 70 80 90 110 140 Igniting current (amps.) ............ 1-18 1.00 0.80 0.73 0.66 0.60 0.50 0.38 It is evident that the energy of the sparks as deduced from the expression &Liz does not give a true measure of their incendivity ; as is also apparent from the fact that the igniting currents for the same mixture of methane and air (7.8%) as determined in the two apparatus A and B with the same circuit conditions before break (e.g. voltage 90 and inductance 0.095 henry) is markedly different. (3) The Current.-We have to consider the effect of using alternat-ing instead of continuous current. Thornton in his researches on the ignition of gaseous mixtures by inductance sparks (Proc. Roy. Xoc. 1914,90 A 272) has employed alternating currents at various frequencies and voltages and so far as the ignition of mixtures of methane and air is concerned has recorded that much larger currents are required to produce ignition than with direct current.For example under the conditions of his experiments the igniting current for a 9.5% methane-air mixture was 0.5 ampere with con-tinuous current at 200 volts (inductance of circuit not stated), Ignition of a 7-Sy0 Methane-Air Mixture. Inductance of Circui PART V. IGNITION BY INDUCTION SPARKS. 19 whilst with alternating cilrreizt a t 200 volts and 100 periods per second i t was 20 amperes root-mean-square (r.m.s.) value (or 28 amperes crest value) although the arrangement of the resistance and inductance of the circuit is stated to have been the same as that med for the experiments with continuous currents.Similar wide differences with alternating current a t lower voltages and frequencies are recorde I by Thornton. To check this remarkable result duplicate series of experiments werc mads with apparatus -4 using ( a ) continuous current at 35 volts with 0.086 henrF inductance and ( b ) alternating current at 23 volts r.m.s. value (33.3 volts crest value) with 0.098 henry inductance 50 periods per second. The break-flashes were produced between contacts of platinum. I n the experiments with alternating current the procedure was to produce a series of 50 sparks (with a given current) at 5 seconds’ interval in a charge of the mixture of methane and air undergoing test. If no ignition occurred a fresh charge of mixture was admitted to the explosion vessel and a further 50 sparks were passed with the current value increased by 0.01 ampere.This process was repeated until ignition occurred, wiien the current value was reduced by 0.01 ampere and two or three hundred sparks mere passed in several charges of the mixture to ensure that the least igniting current had been determined. The reason for this procedure which was unnecessary with continu-ous current (although i t wts followed in several of the trials in order to make the comparison exact) was that i t was impossible to arrange that the break-flash should be produced always when the current mas a t the crest of its cycle. Ignition was in fact, more “ difficult ” with alternating current because the production of a spark at the crest value of the current was a matter of chance.The lowest current at which ignition could be obtained was not, however much different from that required when continuous current was used. Typical results are recorded in Table 11. TABLE 11. Ignition of Methane-Air Mixtures using (a) Continuous and (b) Alternating Czcrrent (50-). Voltage 33. Inductance 0.095 henry . Methane yo ............ (3.15 7-10 7.GO S.00 8-50 9.00 9.60 10.20 10.90 Igniting current (amps.). Continuous 0.43 0.30 0.26 0.24 0.24 0.25 0.28 0.32 0.42 Alternating (crest values) ............... 0.49 0-36 0.30 0.2G 0.24 0.26 0.26 0.30 0.44 It was anticipated that under certain conditions rather more current would be required in the break-flash to ignite a give 20 WHEELER THE IGNITION OF GASES.mixture when the source of supply was alternating than when i t was continuous for the reason that the rapidly changing value of the former might shorten appreciably the duration of the transient arc and the fact that the values for the igniting currents of the mixtures containing the lower percentages of methane are rather higher with alternating than with continuous current is probably due to this effect. Mechanical Conditions. (4) The Nature of the Metal at the Spark-gap.-Since an inductance spark is of the nature of a transient arc current being conducted across the gap through the vapour of the metal i t would seem prob-able that the lower the volatility of the metal conductor the lower would be the igniting current for a given mixture other conditions being constant for less energy would be expended in forming a path for the current or that path might remain open during a longer int,erval of time.Several series of experiments to determine this question were made using apparatus C which was designed to allow of the ready interchange of contacts of different metals whilst preserving as nearly as possible all other experimental conditions constant. The results are summarised in Table 111. Mixtures of methane and air containing between 8.35 and 8.55% of methane were used and the inductance of the circuit was 0.03175 henry. TABLE 111. Igniting Currents with Contacts of Diferent Metals. (Mixtures of Methane and A i r ) . Metal. Cadmium ............ Zinc ..................Aluminium ......... Silver .................. Tin ..................... Copper ............... Nickel. ................. Iron .................. Platinum ............ Gold .................. Boiling point. 778" 91s 1 so0 1955 2270 2310 2330 ? 2450 2450 ? 2530 7 At 80 volts. 0-34 0.44 0.66 0-63 0.58 0.65 0.86 ---Igniting current. Ampere. First series. Second -'-= series. At 100 At 120 At 120 volts. volts. volts. - 0.22 0.23 0-26 0.23 0.25 - - 0.30 0-4 1 0.38 0.32 0.53 0.45 -- 0.49 0.38 0-58 0.55 0.39 0.52 0.49 0.42 0.56 0.48 0.48 0.59 0.50 0.34 The determinations presented considerable difficulty for not only was i t necessary to ensure that the area of contact between the poles 'at the moment of separation was the same in parallel experiments with different metals (a matter requiring fine adjust-ment of the apparatus) but with all the metals except platinu PART V.IGNITION BY INDUCTION SPARKS. 21 and gold the product’ion of a single spark sufficed to oxidise tJhe surfaces to a greater or less degree (thus altering the area of metallic contact) so that in most instances i t was necessary to repolish the surf aces between each break-flash. I n Table 111 the metals have been arranged in order of their boiling points (as recorded in Kaye and Laby’s ( ( Physical and Chemical Constants,” 1821) and it is clear that there is a close relationship between those values and the ( ( igniting currents ” under standard electrical conditions of a given mixture of methane and air.The energy available a t break is utilised mainly iii pro-ducing an arc of volatilised metal and a given quantity of energy presumably produces an arc of short duration if the metal has a high boiling point and an arc of longer duration when the boiling point is relatively low. The duration of the break-flashes with the metals that gave the highest and the lowest results for the igniting currents (gold platinum zinc and cadmium) were determined by photographing them 011 a rapidly revolving plate. The results are recorded in Table IF7. TABLE IV. -Th:~ai:*on of Break-flushes that Causes Ignition of an 8.5% dfethane-Air Mixture. Relative Igniting-current at 120 volts. Duration of Break-31ctal. Ampere. flash. Second.Cndniium ..................... 0.23 0.00321 Z i no ........................... 0.25 0.00234 Platinum ..................... 0.48 0~00081 Gold ........................... 0.50 0~00070 Thus under standard coiiditions a break-flash between cadminm surfaces with a current of 0.23 ampere flowing in the circuit before interruption lasts four times as long as one between platinum surfaces with a current of 0.48 ampere a fact which no doubt accounts mainly if not entirely for both sparks having the same incendivity although the amounts of energy in the circuit a t their iiioments of formation are so different. I n this connexion reference may be made to determinations by v. Lsiig (?Vied. Ann. 1887 31 384) of the minimum arcing potential using poles of different metals for although his results refer to maintained arcs which the break-flashes are not they give a measure of the degree of ease with which such arcs can be produced.The values depended essentially upon the distance apart of the poles and the current flowing in the circuit and could be expressed by a formula p = a + bli in which p is the observed P.D. in volts between the poles I is the distance apart of the poles in mm. and i is t,he current in amperes b being a constant (independent of th 22 WHEELER THE IGNITION OF GASES. current) and a the E.2II.F. required to maintain the arc. Taking the somewhat arbitrary values of 0-5 ampere for i and 0-5 mm. for I as lying within the range of the experiments recorded in Table 111, v. Lang’s determinations were Cadmium 10.9 ; zinc 20.0 ; silver, 20-0; copper 24.0; iron 25-2; nickel 26.4 and platinum 27.8 volts showing that the ease with which the arc is maintained is directly connected with the volatility of the metal.( 5 ) The Rate of Break of Circuit.-Since the incendivity of the break-flashes depends in part on the inductance voltage and since the magnitude of the inductance voltage depends on the product of the coefficient of self-induction 1; and the rate of change di/dt of the current in the circuit i t follows that the rate of break of the circuit-the speed at which the metallic contacts are separated-affects the incendivity of break-flashes produced under otherwise identical conditions. This is demonstrated qualitatively by experiments made with apparatus C using platinum electrodes, which showed that the igniting-current for a given mixture of methane and air was 0.24 ampere when the rate of break was “ rapid ” and 0.60 ampere when it was “ slow,” other conditions remaining constant.(6) The Area of Contact at the Moment of Break-Since the pro-duction of a break-flash depends essentially on the temporary provision of a path for the current through a band of metallic vapour i t follows that the incendivity of a spark produced under otherwise identical conditions will be affected by changes in the area of metallic contact at the moment of break; for the smaller the area of contact at the instant of rupture the more readily will the mass of metal that then remains to form a conductor be turned into vapour that can continue the conduction and the smaller the volume of vapour thus produced the greater will be the amount of energy concentrated in it and the greater in consequence will be its incendivity.Experiments (made with apparatus C) using pole pieces of platinum of different cross-sectional area with their surfaces carefully polished and aligned showed that a lower igniting-current was required for a given mixture of methane and air (under otherwise identical electrical conditions) the smaller the area of the poles. Further information on the effect of the area of contact at the moment of break was obtained when the poles were made of a readily oxidisable metal such as zinc for then unless the surfaces were repolished between each spark the igniting current regularly decreased to a minimum (at which sparking ceased) as oxidation proceeded ; presumably because the coating of oxide gradually reduced the area of metallic contact PART V.IGNITION BY INDUCTION SPARKS. 23 From the fact that so many factors each having considerable influence on the character of the sparks have to be taken into account it will be realised that repetition of the results of appar-ently parallel experiments was by no means easy to obtain. No success attended experiments in which the break of circuit at which the flash occurred was made by hand; it was only by rendering all possible operations mechanical and automatic that any degree of consistency in the igniting currents could be secured and during the course of each series of experiments repeated checks had to be carried out with a standard mixture (8.5% of methane in air) under standard conditions to ensure that no unnoticed change had taken place in the condition of the contacts.From this study of the electrical and mechanical conditions necessary to produce inductance sparks of uniform character itl appeared that the optimum conditions were obtained if (a) The battery voltage was low and the inductance fairly high so as to ensure that the sparks should be maintained primarily by the inductance voltage; ( b ) the metal contacts a t which the sparks were formed were not readily oxidised; (c) the rate of separation of the contacts was rapid ; and ( d ) the area of contact a t the moment of break was small. Comparative series of experiments were made with mixtures of each of the paraffins methane ethane propane, butane and pentane with air using continuous current a t 30 volts with 0.093 henry inductance.The sparks were formed lietween contacts of platinum in apparatus A which was judged to provide the optimum mechanical conditions for the production of sparks of uniform character. The curves relating percentage of inflammable gas in the mixtures with air to " igniting-currents " were similar with each hydrocarbon, to those obtained when secondary discharges (capacity sparks) were used as the means of ignition (see J. 1924 125 1860) save that in each instance differentiation between the more readily ignitible mixtures was not so marked. The same differences in the degree of ignitibility of the paraffins was also observed but again the differences were not so marked.The essential data are given in Table V. The general result of these experiments is to show that so far as the paraffin hydrocarbons are concerned inductance sparks can be considered similar in effect to capacity sparks as means of ignition despite the wide difference there is in the two types both as regards duration and volume. The lolrger duration and larger volume of the inductance sparks apparently have the effect of mask-ing small differences in the ignitibility of those mixtures that are most readily ignited 24 WHEELER THE IGNITION OF GASES. TABLE V. Mixtures of the Parasns with Air. Mixtures Relative most readily igniting Mixtures most ignited by currents. readily ignited Combustible secondary Secondary by inductance gas.discharge. discharge. sparks. \ 2 Y - (J. 1924 125 1863.)* Ra.nge. Mean. Per cent. Ampere. Per cent. Methane ......... 8-3 0.59 7.8-9.0 8.4 Ethans ......... 6-7 0.47 6.0-6.8 6.4 n-Butane ...... 4.2 0.48 3.8-4.4 4.1 n-Pentane ...... 4.0 0.52 3.6-4.2 3-9 n-Propane ...... 5.1 0.36 4-8-5.4 6-1 Relative igniting currents. Inductranee sparks. Ampere. 0.24 0.15 0.12 0.15 0-23 * Currents in the primary circuit (see J. 1920 117 903.) E X P E R I M E N T A L . Apparatus A (Fig. 4). A brass rod passing through the side of a spherical glass vessel of 100 C.C. capacity carried at its end a pointed strip of platinum A to form one of the electrical contacts at which the inductance spark should be produced.The other contact was a platinum rod B. This rod was mounted on a glass support which passed through the ground-glass bearing C and could be caused to revolve by means of the pulley D driven by an electric motor. The glass support was hollow so as to enable electrical connexion to be established (by means of a copper wire E passing through it) between short pieces of thick platinum wire fused into either end. The upper platinum wire carried the contact rod B, and the lower wire dipped into a mercury-cup F whence the electric circuit could be completed. The rod was revolved a t such a speed as to make contact every 5 seconds with the strip which was bent at, an angle (in a manner not apparent from Fig. 4) so that the rod as i t revolved remained in contact with i t during about half a second and then released it suddenly forming a quick break of circuit.Apparatus E (Fig. 5).-The poles were cones of platinum fused into hollow glass supports which passed through ground glass bearings on opposite sides of a glass globe of 100 C.C. capacity. One support A was held by light springs (which allowed it a small amount of movement) so that the platinum pole was normally at the centre of the globe. The support B was attached to a strong spring C which could pull i t half-way through the bearing. A revolving cam (not shown in the diagram) acting on the rod D, pushed this support against the pull of the spring so that its platinum pole made contact periodically with that of A. Electrical con-nexions were made through copper wires passing within the hollo PART V.IGSITION BY INDUCTION SPARKS. 25 supports as in apparatus A. The cam was revolved by an electric motor at such a speed that contact between the poles was made and broken every five seconds and the arrangement was such that contact was maintained during half a second. Apparatus C (Fig. 6).-This apparatus was similar in design to one used by Thornton (The Electrician Sept. 8th 1916). A small solenoid A was supported within a cylindrical explosion vessel of glass of 100 C.C. capacity. Its plunger carried one of the poles a rod 0.5 mm. in diameter. The other pole 1.5 mm. in dia-meter was carried on a fixed support B. The pole pieces were F I G . 4. F I G . 6. F I G . 3 . removable so that different metals could be used.When the solenoid was out of action its plunger dropped so that the end surface of the pole attached to i t rested on that of the fixed pole but on passing an electric current through the coils the plunger was rapidly with-drawn so that a quick break of circuit occurred a t the surfaces of the poles. Make and break of electric circuit in the solenoid (the electrical connesions to which are not shown in the diagram) were made automatically so that the poles were separated every five seconds. Each apparatus could be evacuated so as to eiiable gaseous mixtures of known composition to be introduced. The mixiure 26 BLAIR AND LEDBURY THE PARTIAL FORMALDEHXDE VAPOUR were stored in glass gas-holders over glycerol and water and were analysed before use. I n each series of experiments the electric circuit included a Post Office resistance box (the coils of which were non-inductively wound) to enable small changes of current to be made a measured inductance and an ammeter which was short-circuited when the break-flashes were produced.Except during the experiments with alternating current the source of supply was a battery of dry cells. These experiments were carried out during the years 1914 to 1916. I was assisted throughout by Mr. W. Mason whilst the determinations of the duration of break-flashes with different metals were made by Mr. W. Shepherd to both of whom I am greatly indebted. EXPEILIMENTAL STATION, ESKMEALS CUMBERLAND. [Received November 3rd 1924. 14 WHEELER THE IGNITION OF GASES. 1V.-The Ignition of Gases.Part V. Ignition by Inductance &arks. Mixtures of the Para fins with Air. By RICHARD VERNON WHEELER. ONE object of this part of the research on the ignition of gases was to compare the relative ignitibilities of mixtures of methane and air by inductance sparks (low-tension “ break-flashes ” or momentary arcs) with the values obtained when capacity sparks (high-tension impulsive discharges) were used as described in J., 1920 117 903. For as a source of ignition of gaseous mixtures, an inductance spark (produced when an electric current in an inductive circuit is interrupted by the separation of metallic con-tacts) differs from a capacity spark mainly in its longer duration, the difference being sufficiently wide to make it of importance to discover whether inductance sparks can be regarded with capacity sparks as “ momentary ” sources of heat (see J.1924 125 1858), or whether they more nearly approach in character ‘‘ sustained ” sources such as heated surfaces (see ibid. p. 1869). The character of inductance sparks is most susceptible to change PART V. IGNITION BY INDUCTION SPARKS. 15 in the conditions under which they are produced so that consider-able variation can exist in their incendivity. Fig. 1 constructed mainly from oscillograph records represents the variations with time of current resistance voltage and total heat generated in an inductance spark-gap produced by the rapid separation of metallic contacts. As the area of contact anterior to rupture of the circuit, decreases the electric resistance a t that point increases and heat is generated.Eventually the last remaining points of contact become so hot that the metal volatilises and a t the actual moment of break of circuit a conducting band of metallic vapour is pro-duced. This band rapidly increases in length as the fracture is widened until the spark can no longer be maintained. With a spark of this general character just capable of igniting a given inflammable mixture ignition most probably occurs towards the end of its duration but the precise moment depends upon the exact character of the spark as determined by the rate of increase of resistance and of decay of current in it. For these reasons, in any attempt such as is made in this research to determine the relative ignitibilities of different gaseous mix-t'ures by means of inductance sparks of different intensities we must recog-nise not only the changes measured or deduced purposely made in the intensity but also the changes in the character of the sparks.These changes FIG. 1. e m *! in character may be either inadvertent (as when the condition of the metallic surfaces that are separated changes) or a necessary concomitant of 8 change in intensity (as when the inductance of the circuit is purposely altered). In the production of inductance sparks there are six chief vari-ables which can be divided into two groups according as they relate to ( a ) electrical or ( b ) mechanical conditions. I n the former class are (1) The self-inductance of the circuit ; (2) the impressed voltage ; and (3) the current flowing in the circuit before rupture.The latter class includes (4) The nature of the metal a t the spark gap; (5) the rate of break of circuit; and (6) the area of contact a t the moment of break. Each of these variables can be more or less effectively controlled independently and the influence of each can therefore be determined. The most difficult to control and of which to gauge the influence is the last-named and most of th 16 WHEELER THE IGNITION OF GASES. experimental difficulty of this work has been in maintaining con-stancy of this factor. For with the production of a spark there is a change in the condition of the surfaces at which it passes and with a readily oxidisable metal the change may be sufficient to alter considerably the area of contact available for successive sparks as was observed when the influence of different metals at the spark gap was studied.Platinum or gold surfaces were found to be least susceptible to change and the former have been used for the majority of the experiments. Three different types of apparatus each of which had its advantages for particular series of experiments have been used. These are described in the experimental portion of this paper and are referred to as A B and C. Electrical Conditions. With an inductive circuit carrying continuous current the energy that should theoretically appear in the break-flash is the amount of energy stored electromagnetically in the system and should therefore amount to &Li2. This expression does not however, take into account losses in the circuit or absorption at the sparking-points and although it might be permissible to express the relative incendivities of sparks produced under constant circuit conditions (with a given apparatus) by their energy values it would be mislead-ing to suggest a comparison of these values with others obtained under different circuit conditions and with a different apparatus for producing the sparks.The relative ignitibilities of different gaseous mixtures are therefore expressed in this paper simply by the values of the currents (in amperes) flowing iii the circuit at the moment of interruption which yielded an inductance-spark just capable of causing ignition. (1) The Inductance of the Circuit.-A number of inductances of known magnitudes were prepared consisting of coils of silk-covered copper wire wound on cores of wood so as to be of constant value a t all currents.These were introduced into the circuit from a battery of dry cells and the current a t 90 60 and 30 volts required for the ignition of different mixtures of methane and air by a break-flash at platinum contacts was determined using apparatus A, which enabled a rapid break of circuit to be obtained. A number of the results are shown graphically in Fig. 2 in which percentages of methane are plotted against igniting-currents each curve being for a given value of inductance and impressed voltage of the circuit. From the values used in the construction of these curves the rela-tionship between the igniting current for a given mixture and the inductance of the circuit can be determined.Thus Fig. 3 shows the relationship when mixtures cont,aining 6*0,7.0 and 8.0% of methan PART V. IGNITION BY INDUCTION SPARKS. 17 were used and the impressed voltage was 90 ; additional values used for these curves are the igniting-currents when the inductance was 0.00815 henry namely 1.52 1-18 and 0.94 amp. for the 6.0 7.0, and 8.0% mixtures respectively. The relationship between the values of L of 0.008 and 0.095 henry can be expressed by the equation ,W4 = A ; that is to say the energy required in the circuit before break (+Liz) to produce the igniting sparks was nearly constant. This result is deceptive however for in other series of experiments carried out wibh a different method of producing the sparks the value +Liz was by no means constant.(In this con-METWPIE PER CENT FIG. 2. nexion see Morgan J. 1919 115 24). A simple law coiinect8ing i with L in ignition experiments could only be expected if sparks of the same charact,er could be produced wit'h different values of L, and it would appear not to be possible to vary the intensity of a spark (by varying the inductance) without altering its character ; for a t any particular instant during a break-flash when L is the inductance of the circuit T t,he resistance of the spark-gap R the resistance of the rest of the circuit and V the impressed voltage, thc value for the current is ( V - L d i / d t ) / ( r + R) whilst its limiting value a t thc outset is V/R. (2) The Impressed Voltage.-In general it can be stated that the amount of current in the circuit is of far greater importance tha 18 WHEELER THE IGNITION OF GASES.the impressed voltage as regards the igniting power of the flash produced on breaking the circuit. Especially is this so with highly self-inductive circuits. Thus an 8.0 yo methane-air mixture was ignited by the break-flash with a current of from 0.24 to 0.25. ampere under the conditions of the experiments at any voltage between 10 and 3Q the self-induction of the circuit being 0.095 henry. With higher circuit voltages however the igniting current decreases, as the results recorded in Fig. 2 show. When the contacts at which the break-flash is produced are together the voltage drop between them is zero; as soon as they are completely separated, the voltage between them is equal to the impressed voltage.During the separation of the contacts two actions are tending to make the arc between them persist namely the induced voltage which progressively diminishes and the impressed voltage which pro-gressively increases. If the impressed voltage is high i t will contribute materially to the maintenance of the arc. This effect is more marked when the rate of separation of the contacts is com-paratively slow so that the value of the induced voltage (Ldildt) is low. For example a series of experiments using apparatus B, in which massive electrodes of platinum are drawn apart slowly, gave the results shown in Table I. TABLE I. 0.095 henry. E.2I.I.P. (volts) ...... 25 40 60 70 80 90 110 140 Igniting current (amps.) ............1-18 1.00 0.80 0.73 0.66 0.60 0.50 0.38 It is evident that the energy of the sparks as deduced from the expression &Liz does not give a true measure of their incendivity ; as is also apparent from the fact that the igniting currents for the same mixture of methane and air (7.8%) as determined in the two apparatus A and B with the same circuit conditions before break (e.g. voltage 90 and inductance 0.095 henry) is markedly different. (3) The Current.-We have to consider the effect of using alternat-ing instead of continuous current. Thornton in his researches on the ignition of gaseous mixtures by inductance sparks (Proc. Roy. Xoc. 1914,90 A 272) has employed alternating currents at various frequencies and voltages and so far as the ignition of mixtures of methane and air is concerned has recorded that much larger currents are required to produce ignition than with direct current.For example under the conditions of his experiments the igniting current for a 9.5% methane-air mixture was 0.5 ampere with con-tinuous current at 200 volts (inductance of circuit not stated), Ignition of a 7-Sy0 Methane-Air Mixture. Inductance of Circui PART V. IGNITION BY INDUCTION SPARKS. 19 whilst with alternating cilrreizt a t 200 volts and 100 periods per second i t was 20 amperes root-mean-square (r.m.s.) value (or 28 amperes crest value) although the arrangement of the resistance and inductance of the circuit is stated to have been the same as that med for the experiments with continuous currents.Similar wide differences with alternating current a t lower voltages and frequencies are recorde I by Thornton. To check this remarkable result duplicate series of experiments werc mads with apparatus -4 using ( a ) continuous current at 35 volts with 0.086 henrF inductance and ( b ) alternating current at 23 volts r.m.s. value (33.3 volts crest value) with 0.098 henry inductance 50 periods per second. The break-flashes were produced between contacts of platinum. I n the experiments with alternating current the procedure was to produce a series of 50 sparks (with a given current) at 5 seconds’ interval in a charge of the mixture of methane and air undergoing test. If no ignition occurred a fresh charge of mixture was admitted to the explosion vessel and a further 50 sparks were passed with the current value increased by 0.01 ampere.This process was repeated until ignition occurred, wiien the current value was reduced by 0.01 ampere and two or three hundred sparks mere passed in several charges of the mixture to ensure that the least igniting current had been determined. The reason for this procedure which was unnecessary with continu-ous current (although i t wts followed in several of the trials in order to make the comparison exact) was that i t was impossible to arrange that the break-flash should be produced always when the current mas a t the crest of its cycle. Ignition was in fact, more “ difficult ” with alternating current because the production of a spark at the crest value of the current was a matter of chance.The lowest current at which ignition could be obtained was not, however much different from that required when continuous current was used. Typical results are recorded in Table 11. TABLE 11. Ignition of Methane-Air Mixtures using (a) Continuous and (b) Alternating Czcrrent (50-). Voltage 33. Inductance 0.095 henry . Methane yo ............ (3.15 7-10 7.GO S.00 8-50 9.00 9.60 10.20 10.90 Igniting current (amps.). Continuous 0.43 0.30 0.26 0.24 0.24 0.25 0.28 0.32 0.42 Alternating (crest values) ............... 0.49 0-36 0.30 0.2G 0.24 0.26 0.26 0.30 0.44 It was anticipated that under certain conditions rather more current would be required in the break-flash to ignite a give 20 WHEELER THE IGNITION OF GASES.mixture when the source of supply was alternating than when i t was continuous for the reason that the rapidly changing value of the former might shorten appreciably the duration of the transient arc and the fact that the values for the igniting currents of the mixtures containing the lower percentages of methane are rather higher with alternating than with continuous current is probably due to this effect. Mechanical Conditions. (4) The Nature of the Metal at the Spark-gap.-Since an inductance spark is of the nature of a transient arc current being conducted across the gap through the vapour of the metal i t would seem prob-able that the lower the volatility of the metal conductor the lower would be the igniting current for a given mixture other conditions being constant for less energy would be expended in forming a path for the current or that path might remain open during a longer int,erval of time.Several series of experiments to determine this question were made using apparatus C which was designed to allow of the ready interchange of contacts of different metals whilst preserving as nearly as possible all other experimental conditions constant. The results are summarised in Table 111. Mixtures of methane and air containing between 8.35 and 8.55% of methane were used and the inductance of the circuit was 0.03175 henry. TABLE 111. Igniting Currents with Contacts of Diferent Metals. (Mixtures of Methane and A i r ) . Metal. Cadmium ............ Zinc .................. Aluminium ......... Silver ..................Tin ..................... Copper ............... Nickel. ................. Iron .................. Platinum ............ Gold .................. Boiling point. 778" 91s 1 so0 1955 2270 2310 2330 ? 2450 2450 ? 2530 7 At 80 volts. 0-34 0.44 0.66 0-63 0.58 0.65 0.86 ---Igniting current. Ampere. First series. Second -'-= series. At 100 At 120 At 120 volts. volts. volts. - 0.22 0.23 0-26 0.23 0.25 - - 0.30 0-4 1 0.38 0.32 0.53 0.45 -- 0.49 0.38 0-58 0.55 0.39 0.52 0.49 0.42 0.56 0.48 0.48 0.59 0.50 0.34 The determinations presented considerable difficulty for not only was i t necessary to ensure that the area of contact between the poles 'at the moment of separation was the same in parallel experiments with different metals (a matter requiring fine adjust-ment of the apparatus) but with all the metals except platinu PART V.IGNITION BY INDUCTION SPARKS. 21 and gold the product’ion of a single spark sufficed to oxidise tJhe surfaces to a greater or less degree (thus altering the area of metallic contact) so that in most instances i t was necessary to repolish the surf aces between each break-flash. I n Table 111 the metals have been arranged in order of their boiling points (as recorded in Kaye and Laby’s ( ( Physical and Chemical Constants,” 1821) and it is clear that there is a close relationship between those values and the ( ( igniting currents ” under standard electrical conditions of a given mixture of methane and air.The energy available a t break is utilised mainly iii pro-ducing an arc of volatilised metal and a given quantity of energy presumably produces an arc of short duration if the metal has a high boiling point and an arc of longer duration when the boiling point is relatively low. The duration of the break-flashes with the metals that gave the highest and the lowest results for the igniting currents (gold platinum zinc and cadmium) were determined by photographing them 011 a rapidly revolving plate. The results are recorded in Table IF7. TABLE IV. -Th:~ai:*on of Break-flushes that Causes Ignition of an 8.5% dfethane-Air Mixture. Relative Igniting-current at 120 volts. Duration of Break-31ctal. Ampere. flash. Second. Cndniium ..................... 0.23 0.00321 Z i no ...........................0.25 0.00234 Platinum ..................... 0.48 0~00081 Gold ........................... 0.50 0~00070 Thus under standard coiiditions a break-flash between cadminm surfaces with a current of 0.23 ampere flowing in the circuit before interruption lasts four times as long as one between platinum surfaces with a current of 0.48 ampere a fact which no doubt accounts mainly if not entirely for both sparks having the same incendivity although the amounts of energy in the circuit a t their iiioments of formation are so different. I n this connexion reference may be made to determinations by v. Lsiig (?Vied. Ann. 1887 31 384) of the minimum arcing potential using poles of different metals for although his results refer to maintained arcs which the break-flashes are not they give a measure of the degree of ease with which such arcs can be produced.The values depended essentially upon the distance apart of the poles and the current flowing in the circuit and could be expressed by a formula p = a + bli in which p is the observed P.D. in volts between the poles I is the distance apart of the poles in mm. and i is t,he current in amperes b being a constant (independent of th 22 WHEELER THE IGNITION OF GASES. current) and a the E.2II.F. required to maintain the arc. Taking the somewhat arbitrary values of 0-5 ampere for i and 0-5 mm. for I as lying within the range of the experiments recorded in Table 111, v. Lang’s determinations were Cadmium 10.9 ; zinc 20.0 ; silver, 20-0; copper 24.0; iron 25-2; nickel 26.4 and platinum 27.8 volts showing that the ease with which the arc is maintained is directly connected with the volatility of the metal.( 5 ) The Rate of Break of Circuit.-Since the incendivity of the break-flashes depends in part on the inductance voltage and since the magnitude of the inductance voltage depends on the product of the coefficient of self-induction 1; and the rate of change di/dt of the current in the circuit i t follows that the rate of break of the circuit-the speed at which the metallic contacts are separated-affects the incendivity of break-flashes produced under otherwise identical conditions. This is demonstrated qualitatively by experiments made with apparatus C using platinum electrodes, which showed that the igniting-current for a given mixture of methane and air was 0.24 ampere when the rate of break was “ rapid ” and 0.60 ampere when it was “ slow,” other conditions remaining constant.(6) The Area of Contact at the Moment of Break-Since the pro-duction of a break-flash depends essentially on the temporary provision of a path for the current through a band of metallic vapour i t follows that the incendivity of a spark produced under otherwise identical conditions will be affected by changes in the area of metallic contact at the moment of break; for the smaller the area of contact at the instant of rupture the more readily will the mass of metal that then remains to form a conductor be turned into vapour that can continue the conduction and the smaller the volume of vapour thus produced the greater will be the amount of energy concentrated in it and the greater in consequence will be its incendivity.Experiments (made with apparatus C) using pole pieces of platinum of different cross-sectional area with their surfaces carefully polished and aligned showed that a lower igniting-current was required for a given mixture of methane and air (under otherwise identical electrical conditions) the smaller the area of the poles. Further information on the effect of the area of contact at the moment of break was obtained when the poles were made of a readily oxidisable metal such as zinc for then unless the surfaces were repolished between each spark the igniting current regularly decreased to a minimum (at which sparking ceased) as oxidation proceeded ; presumably because the coating of oxide gradually reduced the area of metallic contact PART V.IGNITION BY INDUCTION SPARKS. 23 From the fact that so many factors each having considerable influence on the character of the sparks have to be taken into account it will be realised that repetition of the results of appar-ently parallel experiments was by no means easy to obtain. No success attended experiments in which the break of circuit at which the flash occurred was made by hand; it was only by rendering all possible operations mechanical and automatic that any degree of consistency in the igniting currents could be secured and during the course of each series of experiments repeated checks had to be carried out with a standard mixture (8.5% of methane in air) under standard conditions to ensure that no unnoticed change had taken place in the condition of the contacts.From this study of the electrical and mechanical conditions necessary to produce inductance sparks of uniform character itl appeared that the optimum conditions were obtained if (a) The battery voltage was low and the inductance fairly high so as to ensure that the sparks should be maintained primarily by the inductance voltage; ( b ) the metal contacts a t which the sparks were formed were not readily oxidised; (c) the rate of separation of the contacts was rapid ; and ( d ) the area of contact a t the moment of break was small. Comparative series of experiments were made with mixtures of each of the paraffins methane ethane propane, butane and pentane with air using continuous current a t 30 volts with 0.093 henry inductance.The sparks were formed lietween contacts of platinum in apparatus A which was judged to provide the optimum mechanical conditions for the production of sparks of uniform character. The curves relating percentage of inflammable gas in the mixtures with air to " igniting-currents " were similar with each hydrocarbon, to those obtained when secondary discharges (capacity sparks) were used as the means of ignition (see J. 1924 125 1860) save that in each instance differentiation between the more readily ignitible mixtures was not so marked. The same differences in the degree of ignitibility of the paraffins was also observed but again the differences were not so marked.The essential data are given in Table V. The general result of these experiments is to show that so far as the paraffin hydrocarbons are concerned inductance sparks can be considered similar in effect to capacity sparks as means of ignition despite the wide difference there is in the two types both as regards duration and volume. The lolrger duration and larger volume of the inductance sparks apparently have the effect of mask-ing small differences in the ignitibility of those mixtures that are most readily ignited 24 WHEELER THE IGNITION OF GASES. TABLE V. Mixtures of the Parasns with Air. Mixtures Relative most readily igniting Mixtures most ignited by currents. readily ignited Combustible secondary Secondary by inductance gas.discharge. discharge. sparks. \ 2 Y - (J. 1924 125 1863.)* Ra.nge. Mean. Per cent. Ampere. Per cent. Methane ......... 8-3 0.59 7.8-9.0 8.4 Ethans ......... 6-7 0.47 6.0-6.8 6.4 n-Butane ...... 4.2 0.48 3.8-4.4 4.1 n-Pentane ...... 4.0 0.52 3.6-4.2 3-9 n-Propane ...... 5.1 0.36 4-8-5.4 6-1 Relative igniting currents. Inductranee sparks. Ampere. 0.24 0.15 0.12 0.15 0-23 * Currents in the primary circuit (see J. 1920 117 903.) E X P E R I M E N T A L . Apparatus A (Fig. 4). A brass rod passing through the side of a spherical glass vessel of 100 C.C. capacity carried at its end a pointed strip of platinum A to form one of the electrical contacts at which the inductance spark should be produced. The other contact was a platinum rod B.This rod was mounted on a glass support which passed through the ground-glass bearing C and could be caused to revolve by means of the pulley D driven by an electric motor. The glass support was hollow so as to enable electrical connexion to be established (by means of a copper wire E passing through it) between short pieces of thick platinum wire fused into either end. The upper platinum wire carried the contact rod B, and the lower wire dipped into a mercury-cup F whence the electric circuit could be completed. The rod was revolved a t such a speed as to make contact every 5 seconds with the strip which was bent at, an angle (in a manner not apparent from Fig. 4) so that the rod as i t revolved remained in contact with i t during about half a second and then released it suddenly forming a quick break of circuit.Apparatus E (Fig. 5).-The poles were cones of platinum fused into hollow glass supports which passed through ground glass bearings on opposite sides of a glass globe of 100 C.C. capacity. One support A was held by light springs (which allowed it a small amount of movement) so that the platinum pole was normally at the centre of the globe. The support B was attached to a strong spring C which could pull i t half-way through the bearing. A revolving cam (not shown in the diagram) acting on the rod D, pushed this support against the pull of the spring so that its platinum pole made contact periodically with that of A. Electrical con-nexions were made through copper wires passing within the hollo PART V.IGSITION BY INDUCTION SPARKS. 25 supports as in apparatus A. The cam was revolved by an electric motor at such a speed that contact between the poles was made and broken every five seconds and the arrangement was such that contact was maintained during half a second. Apparatus C (Fig. 6).-This apparatus was similar in design to one used by Thornton (The Electrician Sept. 8th 1916). A small solenoid A was supported within a cylindrical explosion vessel of glass of 100 C.C. capacity. Its plunger carried one of the poles a rod 0.5 mm. in diameter. The other pole 1.5 mm. in dia-meter was carried on a fixed support B. The pole pieces were F I G . 4. F I G . 6. F I G . 3 . removable so that different metals could be used. When the solenoid was out of action its plunger dropped so that the end surface of the pole attached to i t rested on that of the fixed pole but on passing an electric current through the coils the plunger was rapidly with-drawn so that a quick break of circuit occurred a t the surfaces of the poles. Make and break of electric circuit in the solenoid (the electrical connesions to which are not shown in the diagram) were made automatically so that the poles were separated every five seconds. Each apparatus could be evacuated so as to eiiable gaseous mixtures of known composition to be introduced. The mixiure 26 BLAIR AND LEDBURY THE PARTIAL FORMALDEHXDE VAPOUR were stored in glass gas-holders over glycerol and water and were analysed before use. I n each series of experiments the electric circuit included a Post Office resistance box (the coils of which were non-inductively wound) to enable small changes of current to be made a measured inductance and an ammeter which was short-circuited when the break-flashes were produced. Except during the experiments with alternating current the source of supply was a battery of dry cells. These experiments were carried out during the years 1914 to 1916. I was assisted throughout by Mr. W. Mason whilst the determinations of the duration of break-flashes with different metals were made by Mr. W. Shepherd to both of whom I am greatly indebted. EXPEILIMENTAL STATION, ESKMEALS CUMBERLAND. [Received November 3rd 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700014

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

26 BLAIR AND LEDBURY THE PARTIAL FORMALDEHXDE VAPOUR V .-The Partial Formaldehyde Vapour Pre,ssures of By ETHELBERT WILLIAM BLAIR and WILFRID LEDBURY. A LARGE number of processes based on methods of controlled oxidation of various hydrocarbons (Glock D.R.-P. 109,014 1898 ; Walters P.P. 168,785 ; Willstatter and Bommer Annulen 1921, 422 36 ; Blair and Wheeler J . Xoc. Chem. Ind. 1922 3 0 4 ~ ; 1923, 8 1 ~ ; Berl and Fischer 2. ungew. Chem. 1923 36 297 ; Johnson, B.P. 199,585 1922) have been proposed from time to time for the production on a commercial scale of aqueous solutions of formaldehyde. The comparatively low concentration of formal-dehyde vapour in the effluent gases from such oxidation processes may easily result in depreciated yields of the required product on account of low absorption efficiencies.It is the object of the present investigation to determine the partial formaldehyde vapour pressures of aqueous formaldehyde solutions of different strengths, and hence to ascertain whether under equilibrium conditions of absorption it is possible to effect more or less completely the fixation of highly diluted vapours of formaldehyde. Blair and Wheeler (Zoc. cit.) have shown that under carefully regulated con-ditions the slow oxidation of ethylene yields dilute formaldehyde vapours of concentration of the order of 1.0 to 2.0 mg. per litre, corresponding to vapour pressures of about 0.5 to 1.0 mm. of mercury respectively. The investigations carried out by the same authors, with the object of producing formaldehyde by the controlled oxida-Aqueous Solutions of Formaldehyde.Part I PRESSURES OF AQUEOUS SOLUTIOXS OF FORMALDEHYDE. 27 tion of methane showed that formaldehyde vapours ranging in concentration from 0-2 to 3-0 mg. per litre corresponding to partial pressures of 0.13 to 1-65 mm. of mercury were obtainable under the conditions of their laboratory experiments. I n this connexion it is of importance to determine the maximum strengths of aqueous f orinaldehyde solutions which are obtainable by the continuous absorpt'ion of such vapours under specified conditions. By a study of the partial formaldehyde vapour tensions of solutions at O" and by a comparison of the values so obtained with the corresponding values for 20° the merits or demerits of low-temperature condensa-tion from tthe point of view of formaldehyde fixation can be established.Further the data derived at the lower temperature should indicate the feasibility or otherwise of obtaining formalin solutions of moderate strengths by processes of chilling moist air or other gas containing small concentrations of the vapour. E x P E R I M E N T A L. Treatment of Formalin 8oZutions.-Samples of formalin of approximately 400/ strength by volume and obtained from various sources were found on analysis to contain varying amounts of methyl alcohol as impurity. The formaldehyde present was estimated by the hypoiodite method of Romijn (Analyst 1897 22, 221 ; see also Chem. Ztg. 1901,25,740 ; Ber. 1898,31,1979 ; 1901,34, 2517) which for sufficiently diluted solutions provides trustworthy data even when methyl alcohol is present (Bergstrom J .Amer. Chem. Xoc. 1923 45 215Q). From a determination of the total carbon content in a given n-eight of formalin (Blank and Finkenbeiner, Ber. 1906 39 1326) i t was possible to arrive a t the quant'ity of methyl alcohol present in the solution. In particular cases methyl alcohol was present to the extent of 5-0 t o 10.0% by weight. It has been suggested by Ormandy and Craven in their " Note on Aqueous Formaldehyde Solutions," read before the Cheniical Society that the discrepancies in the previously published values for the densities of such solutions arise from the presence of methyl alcohol and their results appear to substantiate this contention. I n studying the physical properties of aqueous formaldehyde solutions i t is there-fore imperative that any contaminating methyl alcohol shocld be eliminated.These workers succeeded in removing methyl alcohol from formalin solutions by prolonged refluxing with water ; they showed that both the refractive index and the density of a purified formalin solution are linear functions of its concentration. Their data are in agreement with those obtained as a result of a similar investigation by Auerbach and Barschall who however prepared aqueous solutions by passing nitrogen over heated paraformaldehyd 28 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR and absorbing in distilled water the formaldehyde vapour carried forward. The removal of methyl alcohol was effected in the present instance by refluxing the solutions with distilled water the proportion of the latter being determined by the strength of the formaldehyde solution required.For this purpose was employed it litre flask to which was attached a tube 1 inch in diameter and 28 inches in length packed to within a few inches of the top with glass beads. The heating was regulated so that the temperature registered at the head of the column was approximately the boiling point of methyl alcohol (66"). Refluxing for a period of about 36 hours sufficed to remove methyl alcohol from 500 C.C. of the solution ; the odour of the alcohol however could not be detected when the refluxing had proceeded for only a few hours. Acetone was absent from the solution after refluxing. Incidentally it is of interest in this connexion to note that the above method for the removal of methyl alcohol forms the basis of a recent patent for obtaining formalin with only a low content of methyl alcohol (Hirchberg B.P.199,759 1922). The elimination of methyl alcohol from formaldehyde solutions having concentrations of approximately 40% by volume had a marked effect on the stability of these solutions the tendency for paraformaldehyde to separate being enhanced by the removal of the alcohol. Thus a solution containing 5 % of methyl alcohol and having a formaldehyde content of 41.0 g. per 100 C.C. did not deposit paraformaldehyde on prolonged exposure at 0 " whilst with an uncontaminated solution containing 38.7 g. of formaldehyde per 100 c.c. a similar exposure caused the development of an opalescence within a few hours and the eventual deposition of the solid white polymeride.This observation is not, however in agreement with a surmise put forward by Hirchberg (Zoc. cit.) to the effect that methyl alcohol promotes the production of acetals such as methylal which are stated to be conducive to the polymerisation of formaldehyde. I n consequence of the separation of paraformaldehyde a t 0" from the more concentrated formaldehyde solutiqns freed from methyl alcohol it was not possible to determine the partial formaldehyde vapour pressures a t 0" of solutions having strengths appreciably greater than 30 T,. Subsequent to analysis the formaldehyde solutions obtained as a result of the above treatment were allowed to stand a t 16" over a prolonged period before being used for the vapour pressure measure-ments a t 20" or 0".To ascertain the effect of the presence of small amounts of methyl alcohol on the partial formaldehyde vapour pressures of the solutions the pure alcohol was added to a series of the latter in such amounts as to provide in each case a constant ratio CH,O/CH,O PRESSURES OF AQUEOUS SOLUTIONS O F FORMALDEHYDE. 29 iJfethod of Determiriation.-On account of the comparatively low-vapour pressures involved at the ordinary temperature and more especially at O" even in the case of solutions approaching the strength of 40% by volume the " dynamic " or " flow " method was employed in these determinations. Each " carburettor " was charged with 75 C.C. oE the formaldehyde solution under investiga-tion this in the case of a 407G formaldehyde solution corresponding to the presence of 30,000 mg.of formaldehyde. At 20° the passage of 100 litres of moist air through this solution a t the rate of 1.0 litre in 30 mins. effected tho removal of only about 250 mg. of formaldehyde so that for the purpose of computing formaldehyde vapour pressures the concentrations of the formalin solutions were assumed to remain constant during a run involving say the passage of 5 10 20 or 40 litres of moist air. At O" i t was possible to pass through the solution much larger volumes of moist air without appreciably affecting the concentration. The estimation of the formaldehyde carried over by the air stream into the absorption worms,was made by using the hypoiodite method of Romijn (Zoc.cit.), and from the data thus obtained the partial vapour pressure of the formaldehyde was calculated by use of the formultt of Foote and Scholes ( J .Amer. Chem. Xoc. 1911 33 1309) : P = 760v2,'(vl 4 v2) mm. of Hg, where v2 = 22.4 TV/M litres is the volume occupied by the formal-dehyde vapour alone and Jf its molecular weight whilst vl thc volume of the air used reduced to X.T.P. is given by the expression T' is the unreduced volume of t'he air p the pressure of the air collected in the final gas-holder after necessary corrections have been made for water-vapour tension and t is the temperature of the air collected in the gas-holder. An account of the applications and limitations of the " dynamic " method of determining vapour pressures is given by Thomas and Ramsay (J.1923 123 3257), who cite the views of Bermm (Proc. Roy. Xoc. 1904 72 7 2 ; J. Physical Chem. 1905 9 96) the latter after a careful investigation of the subject having concluded that provided proper precautions arc taken the method is capable of yielding sufficiently accurate results. lipparatus. v1 = 273Vp/760(273 + t ) . The accompanying diagram (Fig. 1) shows the details of the apparat'us employed in this investigation. A controlled supply of compressed air was passed through a dust-filter A consisting of an enclosed plug of glass wool and after travelling beyond the stop-cock B and the pressure regulator C was bubbled successively through potash solution and distilled water in D and E respectively 30 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR A calibrated differential rate-gauge constructed on the Venturi principle served to indicate the velocity of the air which was regulated by means of the stop-cock B.Following the differential rate-gauge was a water manometer G whch gave the pressure of the air before its passage through the " carburettor " or " carburettors " and the subsequent Winkler worms. With the exception of the final gas-holder the remainder of the apparatus following the water manometer was immersed in a water thermostat. The bath was FIG. 1. Conpn A i r L-inserted in a large wooden box, - -kbdt and the intervening space between the bath and the walls of the box was loosely paclredwith lagging, consisting of a mixture of magnesite and asbestos fibre.For the experiments a t 20° the requisite temperature was maintained (within -J= 0.05") by means of a Lowry thermo-regulator whilst ice uncontaminated with foreign substances was introduced into the bath to keep the temperature at 0". The long worm H served to bring the inflowing air to the required temperature. This was followed by a specially designed " carburettor " (or in the experi-ments at 0" by two " carburettors ") containing 75 C.C. of the formaldehyde solution under investigation. The object of it PRESSURES O F AQUEOUS SOLUTIOXS OF BORML4LDEHYDE. 32 construction was to permit the incoming stream of air to pass through the formaldehyde solution in the vertical worm and to cause the air bubbles as they emerged into the splash-trap at the top to force over a part of the formaldehyde solution a t the head of the worm into the glass reservoir shown.Fresh formaldehyde solution was thus drawn in a t the base of the vertical worm and the unsaturated air came at the outset into contact with fresh formalin solution. At 20" when two such " carburettors " were connected in series the amount of formaldehyde vapour carried over by a given volume of air was practically unchanged; hence, at 20° one " carburettor " only was in use during the greater part of the investigation. The air saturated at this stage with formal-dehyde vapour passed along the horizontal tube L which in the experiments at the higher temperature was maintained above the temperature of the bath by an electrically heated coil of resistance wire.Under these conditions no condensation of water vapour and consequent premature absorption of formaldehyde vapour occurred during the passage of the vapour-laden air along the tube. For the absorption of formaldehyde vapour two or three Winkler worms containing distilled water were connected in series. The issuing air stripped of formaldehyde vapour entered a graduated, water-filled gas-holder a t a pressure which was maintained constant, throughout the whole of the experiments by means of a constant-level overflow. By employing a constant height of formaldehyde solution in the (' carburettor " and constant heights of water in the Winkler worms and by making the necessary alterations in the level of the overflow the pressure of the air entering the " car-burettor," and issuing therefrom was kept constant.Thus the pressure conditions throughout the whole series of determinations were stmdardised. Such an adjustment of pressure conditions is necessary since the amount of formaldehyde carried over by a given reduced volume of air is dependent on the pressure of its delivery as well as on the temperature. The air was forced through the apparatus at a velocity of 1 litre in 30 mins. since it was found from preliminary trials that if the rate of Eow was diminished below this value the amount of formaldehyde vapour per unit volume of air was unaltered for a given formalin solutioii. Adopting the method of procedure outlined above a number of determinations were made of the partial formaldehyde vapour pressure of each solution under investigation.For each determination totals of 5 10 15 or 20 litres of moist air were passed according to the strength of the formalin solution in the " carburettor." As a result of data derived from earlier experiments it was found justifiable to dispense with the third TVinlder worm of the absorptio 32 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR train since even in the case of the relatively concentrated vapours, issuing from a solution containing 38 g. of formaldehyde per 100 c.c., there was no detectable amount of formaldehyde in the water at this stage. I n the case of the second absorption worm small amounts of formaldehyde of the order of 0.1 to 0.2 mg. were found condensed during the passage of the more concentrated vapours.This worm was permanently retained throughout the investigation. Formaldehyde Vapour Pressures of Aqueous Formaldehyde Solutions at 20". Formalin solutions from which methyl alcohol had been elimin-ated in the manner previously described were exposed a t 15" before FIG. 2. 1-10 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0 5.0 10.0 15.0 20.0 25.0 30.0 35. Litres of air passed through formaldehyde solutions. introduction into the " carburettor." The '' carburettor " and its contents were then left over-night in the t'hermostat at 20" prior to the vapour-pressure determinat,ions. With the exception of the formaldehyde solution of approximately 40% strength all the solutions examined exhibited exceptionally low init,ial formaldehyde vapour pressures but as increasing volumes of air for successive determinations were passed through each of these sol~t~ions the pressure values increased rapidly at first then more slowly rising to constant maximum values.The accompanying curves A B C and D (Fig. 2) depict graphically the relationship between the partial pressure of t.he formaldehyde vapour in mm. of mercury and the total volume of air in litres passed through a solution of given strength. The examination of the formalin solution containing 40.2 g. of formal PRESSURES OF AQUEOUS SOLUTIONS OF FORMALDEHYDE. 33 dehyde per 100 C.C. did not reveal on the past of the partid presaure, any marked tendency to increase in magnitude such as was evidenced with the more dilute solutions. The equilibrium or asymptotic values of the formaldehyde vapour pregsures that is the constant values reached when the pawage of a sufficient volume of air through the solutions had brought about apparent equilibrium *conditions between the liquid and vapour phases are given in Table I together with the corresponding concentrations of formaldehyde vapour in the effluent air.TABLE I. Gms. of formaldehyde per 100 C.C. of Mg. of formaldehyde vapour per Iitre Partial pressure of formaldehyde formalin solution ..................... 9.52 19-7 29.5 31.1 40.2 of issuing air ........................... 0-59 1-01 1-39 1-40 1.75 vapour in mm. of mercury ......... 0.340 0.575 0.780 0.795 1-025 FIU. 3. FIG. 5. cfm. of fornaaldehyde per 100 C.C. of solution. Gms. of forma2dehyde per 100 ex.of solution. OH,O/CH,O = 0'13. The solution containing 31.1 g. of formaldehyde per 100 C.C. was exposed prior to the vapour-pressure determinations at 20" in the thermostat for a number of days ; the value given in the above table for the vapour pressure ia the mean of several almost coincident values vix. 0.797 0.793 0-795 mm. of Hg which were subsequently obtained. In Fig. 3 the partial pressures of the formaldehyde vapour, expressed in mm. of mercury are plotted as ordinates against the corresponding concentrations of the aqueous formaldehyde solutions in g. per 100 C.C. as abscissae. It is seen that the partial pressure of the formaldehyde vapour is not a linear function of the formaldehyde concentration in the liquid phase (compare the relation between density and refractive index of a formaldehyde solution and the concentration of the latter a8 demonstrated by Ormandy and Craven Zoc.cit.) but that the rate of increase of the partial pressure VOL. CXXVII. 34 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR with the concentration falls off slightly with increasing concentration of the solution. Addition of 3Iethy.l Alcohol to Aqueous Formaldehyde Solutions at 20".-Pure methyl alcohol free from acetone was added to the aqueous formaldehyde solutions treated in the manner previously described in such amount that for all the solutions a constant small ratio CH,O/CH,O vix. 0-13 by weight was preserved. As in the case of the purified aqueous formaldehyde solutions there was again for certain solutions a rise in t,he vapour pressure values until maximum values were attained.Litres of air passed through formaldehyde solutions. A comparison of the curves in Fig. 2 with those in Fig. 4 shows the effects of addition of small quantities of methyl alcohol to aqueous f ormnldehyde solutions. The partial pressure values at the outset approximate more closely to the final maximum values than is the case with uncontaminated formaldehyde solutions ; the apparent equilibrium vapour pressures are raised in all cases above those previously determined ; and the difference of vapour pressure due to increase in the formaldehyde concentration of tlhe solution is more pronounced in this series of determinations. Table I1 gives the apparent equilibrium values of the partial pressures of these formalin solutions together with the corresponding concen PRESSURES OF AQUEOITS SOLUTIOPU'S O F FORMALDEHYDE.35 trations of formaldehyde vapour in the effluent air. The curve (Fig. 5) shows diagrammatically the relation of the partial pressure of the formaldehyde vapour to the formaldehyde concentration of the solution. TABLE Ir. Gms. of formaldehyde per 100 C.C. of formalin solution. CH,O/CH,O = Ng. of formaldehyde vapour per litro of Partial pressure of f ormzldehyde vapour 0.13 .......................................... 9-22 19.1 28.3 37.5 issuing air ................................. 0.62 1.29 1-86 2.32 in mm. of Hg .............................. 0.362 0.760 1.0s 1.31 When the forrnaldehyde-content of the solution is expressed in g.per 100 c.c. there is a nearer approach in this case to a straight line relationship between formaldehyde-concentration and the corresponding partial pressure of formaldehyde vapour. There is a strill nearer approach to a 'linear relationship when the forznalde-hyde-concentration is expressed as g. per 100 g. of solution since the specific gravities of forrnalin solutions increase with concen-tration t'he value for a 40y0 solution being about 1-0s. Formaldehyde Vapoiir I't't?sswes of Aqueous Formaldehyde Solutions a t 0". Formalin solutions freed from methyl alcohol were allowed to stand at the ordinary temperature for several days and subsequently introduced into the '' carburettors " (two in series were employed in these experinients at 0"). Prior to the vapour-pressure determin-ations the " carburettors " w-ere left in the thermostat over-night at 0".With each of the solutions examined as increasing volumes of air were passed the partial vapour pressures decreased fairly rapidly at first and then more slowly reached an almost constant miriimum value. It will be remembered that the partial vapour prcssure rose to an approximately constant maximum value when a purified formalin solution after standing for a short period at 15" was introduced into a thermostat a t 20" and air passed for the purpose of determining its partial f ornialdehydc vapour pressure at tJhat temperature. The accompanying curves A B C and D of Fig. 6 show graphically the manner in which the partial formaldehyde vapour pressures of the solutions decrease as increasing volumes of air are passed.Thc a p p r m t cynilibrium Td1ies o€ the formaldehyde vapour pressures that is the constant minimum values reached when the passage of a sufficient volume of air through the solutions has c 36 BLAIR AND LEDBURY THE PAFLTIAL FORMALDEHYDE VAPOUR brought about apparent equilibrium conditions between liquid and vapour phmes are given in Table 111 together with the correspond-ing concentrations of formaldehyde vapour in the effluent air. In the case of a formaldehyde solution containing 16 g. of formaldehyde per 100 c.c. which had been exposed at 0" in the thermostat for 13 da$s before the passage of air partial pressure values were obtained which were constant from the commencement ; vix., 0.104 0.100 0.102 mm.of Hg. The mean of these values falls very closely to the curve in Fig. 7. FIG. 6 . Litres of air passed through formaldehyde solzrtions. TABLE 111. Gms. of formaldehyde per 100 C.C. of Mg. of formaldehyde vapour per litre of Partial pressure of formaldehyde vapour formalin solution ........................ 8.09 15.68 20.63 31.25 issuing air ................................. 0.095 0.166 0.201 0.265 in mm. of Hg .............................. 0.056 0.102 0.118 0.157 From the data provided in Table I11 and from the curve of Fig. 7, it is evident that the partial formaldehyde vapour pressure is not a linear function of the concentration of the solution but that increase in partial pressure with concentration is less pronounced at 0".For the purpose of comparing the partial formaldehyde vapour-pressure values at 0" with those previously determined at 20" the curves A and B are given in Fig. 8. A is the partial formaldehyde vapour-pressure-solution-concentration curve for O" and B the corresponding curve plotted on the same scale for 20". For reasons cited above it was not possible to study the vapour-pressure charac-teristics of formalin solutiom much above 30% in strength. The ratio Pressure of formaldehyde vapour a t O"/Pressure o PRESSURES OF AQUEOUS SOLUTIONS OF FORMALDEHYDE. 37 formaldehyde vapour at 20" varies progressively from 0.18 for a solution containing 30 g. of formaldehyde per 100 C.C. to 0.22 for a solution containing 5 g. of formaldehyde per 100 c.c. whilst the ratio Pressure of aqueous vapour a t O"/Bressure of aqueous vapour at 20" = 4*53/17.4 = 0.28.From these values it appears it is possible to obtain a more con-centrated formalin solution by chilling warm air or gas containing water vapour and formaldehyde vapour to O" than by cooling the same gas to 20". In such a process the difference of solution strength a t the two temperatures would be more pronounced in the case of the more concentrated vapours. FIG. 7. ma. 5. Gm8. of formaldehyde per 100 C.C. of Gms. of formaldehyde per 100 C.C. of solution. solution. Addition of Methyl Alcohol to Aqueous Formaldehyde Xolutions at ()".-To aqueous formaldehyde solutions methyl alcohol free from acetone was added in such amount tthat the ratio WtCH,Q/WtCH2Q =0.13 this being the ratio employed in the corresponding vapour-pressure determinations at 20".The data obtained for the solutions studied indicated that the addition of small amounts of methyl alcohol to aqueous formaldehyde solutions had very little effect on the &a1 formaldehyde partial vapour pressure values of such solutions. Thus from the curve (Fig. 7) it is seen that the vapour pressure of an aqueous solution containing lO.8 g. of formaldehyde per 100 C.C. in the absence of methyl alcohol is very approximately equivalent to 0.87 mm. of mercury. This value is almost identical with that obtained with a solution of corresponding strength containing a littl 38 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR methyl alcohol (CH,O/CH,O = 0.13 by weight) wix. 0.072 mm.of mercury. The divergence between the initial and final values is not so pronounced as in the previous instance. Discussion of Results. Aqueous formaldehyde solutions do not exhibit the characteristic properties of gas-water systems but on the contrary at the ordinary temperature behave from the point of view of partial vapour pressures in a manner suggestive of solutions in water of a soluble liquid of comparatively high boiling point e.g. glycerol in water. Determinations of the apparent molecular weight of formaldehyde in its aqueous solutions as well as the vapour tension characteristics of these solutions indicate the existence in the dissolved state of complex molecules in addition to the simple molecules of formal-dehyde. The heavier molecules of the solute may include not only one or more polymerides of formaldehyde but also products com-plex or otherwise derived as a result of hydration of the formal-dehyde ; consideration of the distinctive properties of aqueous formaldehyde solutions and evidences of the residual affinity exerted by the simple formaldehyde molecule by reason of its doubly linked oxygen atom render such a postulate feasible.A possible interpretation of the conditions existing in an aqueous formaldehyde solution may be symbolically represented as follows :-complex -+ CB,O [Formaldehyde] hydrated etc . .t- (simple molecules). Assuming the representation provides a reasonable although vague conception of the equilibrium conditions within the solution, then from apparent molecular-weight determinations vapour-pressure considerations etc.the equilibrium a t the ordinary temperature must correspond to a large excess of the heavier molecules. The partial pressure at a particular temperature of the formaldehyde vapour above an aqueous formaldehyde solution will be almost entirely dependent on the concentration of the simple molecular form of the aldehyde since the heavier molecules will possess a low volatility in view of tlheir relatively high molecular weights. When a formaldehyde solution which had been treated for the removal of methyl alcohol was introduced into a thermostat main-tained at 20° after previously standing for several days at 15" and air was bubbled through the solution as in the above determinations, there was an increase of the formaldehyde vapour pressure to a constant maximum value as increasing volumes of air were passed.Air passing through the solution at any particular moment takes u PRESSURES OF AQUEOUS SOLUTIONS OF FORMALDEHYDE. 39 formaldehyde vapour in amount corresponding to the concentration of simple formaldehyde molecules. It is assumed that the new equilibrium conditions between the complex and the simple molecules in solution brought about by raising the temperature is only gradually approached as time elapses but that the velocity of this approach or in other words the amount of simple formaldehyde produced in unit time a t 20" by the transformation of the complex, is greater than the rate of removal of formaldehyde from solution under the influence of its vapour pressure; this vapour pressure being a function of the concentration of the simple molecular form of the aldehyde.Since the velocity of transformation is initially greater than that of removal simple formaldehyde will accumulate at this temperature in excess of its original concentration. This accumulation of the simple form will exert a two-fold influence ; fist by reason of its active mass in solution it will lower the velocity of transformation of the complex and secondly it will increase the velocity of the removal of formaldehyde from solution since the latter is dependent on the concentration of the simple molecular form. I n the course of time the two velocities will be equalised and the amount of formaldehyde vapour removed a t 20" by the passage of air from the solut'ion in a given time will reach a constant maximum value.The gradual attainment of constant values by the formaldehyde vapour pressures a t 0" can also be explained by the gradual read-justment of the equilibrium conditions between complex and simple molecules in solution necessitated by change of t,emperature. A formaldehyde solution which had been exposed for several days a t Z O O , prior to determinations a t 20" being carried out provided a series of vapour pressure values which were almost constant from the outset. These values corresponded with a point lying very close to the curve of Fig. 3. A similar procedure in the case of a solution a t 0" made i t evident that in this case also the equilibrium condition had been brought about by prolonged exposure a t the temperature under consideration.The latter observations lend support to the hypo-thesis put f oi-ward in explanation of the variations involved. The addition of a small amount (CH,O,/CH,O = 0.13) of methyl alcohol to an aqueous formaldehyde solution not only brings about, a t Z O O a nearer approach of the vapour pressure determined a t the outset to those determined after the passage of large volumes of air, but also produces a considerable increase (0.60 to 0-80 mm. of Hg for a solution containing 20 g. of CH,O per 100 c.c.) in the constant maximum values eventually at'tained. At 0" the equilibrium vapour pressure values were affected only very slightly by the addition oE small amounts of methyl alcohol. In the course of 40 VALTON THE DETECTION OF METHYLAMINE further investigation the results of which i t is hoped to publish at a later date i t was found that the partial formaldehyde vapour pressure of a 15% methyl-alcoholic solution of formaldehyde at 20" was more than double that of an aqueous solution of corre-sponding strength.This would explain the relatively high values found for the formaldehyde vapour pressures of formalin solutions containing methyl alcohol including solutions of commercial f ormalin , Summary. The partial formaldehyde vapour pressures of aqueous formalde-hyde solutions freed from methyl alcohol have been determined at 20" and 0" by the " dynamic " method. After an initial exposure of a solution at 15" an increase of the partial pressure values as increasing volumes of air were passed until the subsequent attainment of a constant maximum value was noted at Z O O whilst a t 0" the continuous passage of air through a solution was shown to bring about a lowering of the partial formalde-hyde vapour pressure until a constant minimum value was reached.The addition of methyl alcohol to an aqueous formaldehyde solution decreases the divergence between the initially and finally observed values of the partial formaldehyde vapour pressures and, in the case of solutions at 20" enhances the constant maximum value eventually obtained. Under these latter conditions there is a nearer approach to a linear relationship between formaldehyde partial vapour pressure and concentration. An hypothesis has been put forward to explain certain of the observations made.Further investigations are being made on the properties of aqueous and methyl-alcoholic solutions of formaldehyde. This work was carried out for the Chemistry Research Board of the Department of Scientific and Industrial Research to whom we are indebted for permission to publish these results. MAIN LABORATORY R.N. CORDITE FACTORY, HOLTON HEATX DORSET. [Received September 9th 1924. 26 BLAIR AND LEDBURY THE PARTIAL FORMALDEHXDE VAPOUR V .-The Partial Formaldehyde Vapour Pre,ssures of By ETHELBERT WILLIAM BLAIR and WILFRID LEDBURY. A LARGE number of processes based on methods of controlled oxidation of various hydrocarbons (Glock D.R.-P. 109,014 1898 ; Walters P.P. 168,785 ; Willstatter and Bommer Annulen 1921, 422 36 ; Blair and Wheeler J .Xoc. Chem. Ind. 1922 3 0 4 ~ ; 1923, 8 1 ~ ; Berl and Fischer 2. ungew. Chem. 1923 36 297 ; Johnson, B.P. 199,585 1922) have been proposed from time to time for the production on a commercial scale of aqueous solutions of formaldehyde. The comparatively low concentration of formal-dehyde vapour in the effluent gases from such oxidation processes may easily result in depreciated yields of the required product on account of low absorption efficiencies. It is the object of the present investigation to determine the partial formaldehyde vapour pressures of aqueous formaldehyde solutions of different strengths, and hence to ascertain whether under equilibrium conditions of absorption it is possible to effect more or less completely the fixation of highly diluted vapours of formaldehyde.Blair and Wheeler (Zoc. cit.) have shown that under carefully regulated con-ditions the slow oxidation of ethylene yields dilute formaldehyde vapours of concentration of the order of 1.0 to 2.0 mg. per litre, corresponding to vapour pressures of about 0.5 to 1.0 mm. of mercury respectively. The investigations carried out by the same authors, with the object of producing formaldehyde by the controlled oxida-Aqueous Solutions of Formaldehyde. Part I PRESSURES OF AQUEOUS SOLUTIOXS OF FORMALDEHYDE. 27 tion of methane showed that formaldehyde vapours ranging in concentration from 0-2 to 3-0 mg. per litre corresponding to partial pressures of 0.13 to 1-65 mm. of mercury were obtainable under the conditions of their laboratory experiments.I n this connexion it is of importance to determine the maximum strengths of aqueous f orinaldehyde solutions which are obtainable by the continuous absorpt'ion of such vapours under specified conditions. By a study of the partial formaldehyde vapour tensions of solutions at O" and by a comparison of the values so obtained with the corresponding values for 20° the merits or demerits of low-temperature condensa-tion from tthe point of view of formaldehyde fixation can be established. Further the data derived at the lower temperature should indicate the feasibility or otherwise of obtaining formalin solutions of moderate strengths by processes of chilling moist air or other gas containing small concentrations of the vapour.E x P E R I M E N T A L. Treatment of Formalin 8oZutions.-Samples of formalin of approximately 400/ strength by volume and obtained from various sources were found on analysis to contain varying amounts of methyl alcohol as impurity. The formaldehyde present was estimated by the hypoiodite method of Romijn (Analyst 1897 22, 221 ; see also Chem. Ztg. 1901,25,740 ; Ber. 1898,31,1979 ; 1901,34, 2517) which for sufficiently diluted solutions provides trustworthy data even when methyl alcohol is present (Bergstrom J . Amer. Chem. Xoc. 1923 45 215Q). From a determination of the total carbon content in a given n-eight of formalin (Blank and Finkenbeiner, Ber. 1906 39 1326) i t was possible to arrive a t the quant'ity of methyl alcohol present in the solution. In particular cases methyl alcohol was present to the extent of 5-0 t o 10.0% by weight.It has been suggested by Ormandy and Craven in their " Note on Aqueous Formaldehyde Solutions," read before the Cheniical Society that the discrepancies in the previously published values for the densities of such solutions arise from the presence of methyl alcohol and their results appear to substantiate this contention. I n studying the physical properties of aqueous formaldehyde solutions i t is there-fore imperative that any contaminating methyl alcohol shocld be eliminated. These workers succeeded in removing methyl alcohol from formalin solutions by prolonged refluxing with water ; they showed that both the refractive index and the density of a purified formalin solution are linear functions of its concentration.Their data are in agreement with those obtained as a result of a similar investigation by Auerbach and Barschall who however prepared aqueous solutions by passing nitrogen over heated paraformaldehyd 28 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR and absorbing in distilled water the formaldehyde vapour carried forward. The removal of methyl alcohol was effected in the present instance by refluxing the solutions with distilled water the proportion of the latter being determined by the strength of the formaldehyde solution required. For this purpose was employed it litre flask to which was attached a tube 1 inch in diameter and 28 inches in length packed to within a few inches of the top with glass beads. The heating was regulated so that the temperature registered at the head of the column was approximately the boiling point of methyl alcohol (66").Refluxing for a period of about 36 hours sufficed to remove methyl alcohol from 500 C.C. of the solution ; the odour of the alcohol however could not be detected when the refluxing had proceeded for only a few hours. Acetone was absent from the solution after refluxing. Incidentally it is of interest in this connexion to note that the above method for the removal of methyl alcohol forms the basis of a recent patent for obtaining formalin with only a low content of methyl alcohol (Hirchberg B.P. 199,759 1922). The elimination of methyl alcohol from formaldehyde solutions having concentrations of approximately 40% by volume had a marked effect on the stability of these solutions the tendency for paraformaldehyde to separate being enhanced by the removal of the alcohol.Thus a solution containing 5 % of methyl alcohol and having a formaldehyde content of 41.0 g. per 100 C.C. did not deposit paraformaldehyde on prolonged exposure at 0 " whilst with an uncontaminated solution containing 38.7 g. of formaldehyde per 100 c.c. a similar exposure caused the development of an opalescence within a few hours and the eventual deposition of the solid white polymeride. This observation is not, however in agreement with a surmise put forward by Hirchberg (Zoc. cit.) to the effect that methyl alcohol promotes the production of acetals such as methylal which are stated to be conducive to the polymerisation of formaldehyde.I n consequence of the separation of paraformaldehyde a t 0" from the more concentrated formaldehyde solutiqns freed from methyl alcohol it was not possible to determine the partial formaldehyde vapour pressures a t 0" of solutions having strengths appreciably greater than 30 T,. Subsequent to analysis the formaldehyde solutions obtained as a result of the above treatment were allowed to stand a t 16" over a prolonged period before being used for the vapour pressure measure-ments a t 20" or 0". To ascertain the effect of the presence of small amounts of methyl alcohol on the partial formaldehyde vapour pressures of the solutions the pure alcohol was added to a series of the latter in such amounts as to provide in each case a constant ratio CH,O/CH,O PRESSURES OF AQUEOUS SOLUTIONS O F FORMALDEHYDE.29 iJfethod of Determiriation.-On account of the comparatively low-vapour pressures involved at the ordinary temperature and more especially at O" even in the case of solutions approaching the strength of 40% by volume the " dynamic " or " flow " method was employed in these determinations. Each " carburettor " was charged with 75 C.C. oE the formaldehyde solution under investiga-tion this in the case of a 407G formaldehyde solution corresponding to the presence of 30,000 mg. of formaldehyde. At 20° the passage of 100 litres of moist air through this solution a t the rate of 1.0 litre in 30 mins. effected tho removal of only about 250 mg. of formaldehyde so that for the purpose of computing formaldehyde vapour pressures the concentrations of the formalin solutions were assumed to remain constant during a run involving say the passage of 5 10 20 or 40 litres of moist air.At O" i t was possible to pass through the solution much larger volumes of moist air without appreciably affecting the concentration. The estimation of the formaldehyde carried over by the air stream into the absorption worms,was made by using the hypoiodite method of Romijn (Zoc.cit.), and from the data thus obtained the partial vapour pressure of the formaldehyde was calculated by use of the formultt of Foote and Scholes ( J . Amer. Chem. Xoc. 1911 33 1309) : P = 760v2,'(vl 4 v2) mm. of Hg, where v2 = 22.4 TV/M litres is the volume occupied by the formal-dehyde vapour alone and Jf its molecular weight whilst vl thc volume of the air used reduced to X.T.P.is given by the expression T' is the unreduced volume of t'he air p the pressure of the air collected in the final gas-holder after necessary corrections have been made for water-vapour tension and t is the temperature of the air collected in the gas-holder. An account of the applications and limitations of the " dynamic " method of determining vapour pressures is given by Thomas and Ramsay (J. 1923 123 3257), who cite the views of Bermm (Proc. Roy. Xoc. 1904 72 7 2 ; J. Physical Chem. 1905 9 96) the latter after a careful investigation of the subject having concluded that provided proper precautions arc taken the method is capable of yielding sufficiently accurate results.lipparatus. v1 = 273Vp/760(273 + t ) . The accompanying diagram (Fig. 1) shows the details of the apparat'us employed in this investigation. A controlled supply of compressed air was passed through a dust-filter A consisting of an enclosed plug of glass wool and after travelling beyond the stop-cock B and the pressure regulator C was bubbled successively through potash solution and distilled water in D and E respectively 30 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR A calibrated differential rate-gauge constructed on the Venturi principle served to indicate the velocity of the air which was regulated by means of the stop-cock B. Following the differential rate-gauge was a water manometer G whch gave the pressure of the air before its passage through the " carburettor " or " carburettors " and the subsequent Winkler worms.With the exception of the final gas-holder the remainder of the apparatus following the water manometer was immersed in a water thermostat. The bath was FIG. 1. Conpn A i r L-inserted in a large wooden box, - -kbdt and the intervening space between the bath and the walls of the box was loosely paclredwith lagging, consisting of a mixture of magnesite and asbestos fibre. For the experiments a t 20° the requisite temperature was maintained (within -J= 0.05") by means of a Lowry thermo-regulator whilst ice uncontaminated with foreign substances was introduced into the bath to keep the temperature at 0". The long worm H served to bring the inflowing air to the required temperature.This was followed by a specially designed " carburettor " (or in the experi-ments at 0" by two " carburettors ") containing 75 C.C. of the formaldehyde solution under investigation. The object of it PRESSURES O F AQUEOUS SOLUTIOXS OF BORML4LDEHYDE. 32 construction was to permit the incoming stream of air to pass through the formaldehyde solution in the vertical worm and to cause the air bubbles as they emerged into the splash-trap at the top to force over a part of the formaldehyde solution a t the head of the worm into the glass reservoir shown. Fresh formaldehyde solution was thus drawn in a t the base of the vertical worm and the unsaturated air came at the outset into contact with fresh formalin solution. At 20" when two such " carburettors " were connected in series the amount of formaldehyde vapour carried over by a given volume of air was practically unchanged; hence, at 20° one " carburettor " only was in use during the greater part of the investigation.The air saturated at this stage with formal-dehyde vapour passed along the horizontal tube L which in the experiments at the higher temperature was maintained above the temperature of the bath by an electrically heated coil of resistance wire. Under these conditions no condensation of water vapour and consequent premature absorption of formaldehyde vapour occurred during the passage of the vapour-laden air along the tube. For the absorption of formaldehyde vapour two or three Winkler worms containing distilled water were connected in series. The issuing air stripped of formaldehyde vapour entered a graduated, water-filled gas-holder a t a pressure which was maintained constant, throughout the whole of the experiments by means of a constant-level overflow.By employing a constant height of formaldehyde solution in the (' carburettor " and constant heights of water in the Winkler worms and by making the necessary alterations in the level of the overflow the pressure of the air entering the " car-burettor," and issuing therefrom was kept constant. Thus the pressure conditions throughout the whole series of determinations were stmdardised. Such an adjustment of pressure conditions is necessary since the amount of formaldehyde carried over by a given reduced volume of air is dependent on the pressure of its delivery as well as on the temperature.The air was forced through the apparatus at a velocity of 1 litre in 30 mins. since it was found from preliminary trials that if the rate of Eow was diminished below this value the amount of formaldehyde vapour per unit volume of air was unaltered for a given formalin solutioii. Adopting the method of procedure outlined above a number of determinations were made of the partial formaldehyde vapour pressure of each solution under investigation. For each determination totals of 5 10 15 or 20 litres of moist air were passed according to the strength of the formalin solution in the " carburettor." As a result of data derived from earlier experiments it was found justifiable to dispense with the third TVinlder worm of the absorptio 32 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR train since even in the case of the relatively concentrated vapours, issuing from a solution containing 38 g.of formaldehyde per 100 c.c., there was no detectable amount of formaldehyde in the water at this stage. I n the case of the second absorption worm small amounts of formaldehyde of the order of 0.1 to 0.2 mg. were found condensed during the passage of the more concentrated vapours. This worm was permanently retained throughout the investigation. Formaldehyde Vapour Pressures of Aqueous Formaldehyde Solutions at 20". Formalin solutions from which methyl alcohol had been elimin-ated in the manner previously described were exposed a t 15" before FIG. 2. 1-10 1.00 0.90 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0 5.0 10.0 15.0 20.0 25.0 30.0 35.Litres of air passed through formaldehyde solutions. introduction into the " carburettor." The '' carburettor " and its contents were then left over-night in the t'hermostat at 20" prior to the vapour-pressure determinat,ions. With the exception of the formaldehyde solution of approximately 40% strength all the solutions examined exhibited exceptionally low init,ial formaldehyde vapour pressures but as increasing volumes of air for successive determinations were passed through each of these sol~t~ions the pressure values increased rapidly at first then more slowly rising to constant maximum values. The accompanying curves A B C and D (Fig. 2) depict graphically the relationship between the partial pressure of t.he formaldehyde vapour in mm.of mercury and the total volume of air in litres passed through a solution of given strength. The examination of the formalin solution containing 40.2 g. of formal PRESSURES OF AQUEOUS SOLUTIONS OF FORMALDEHYDE. 33 dehyde per 100 C.C. did not reveal on the past of the partid presaure, any marked tendency to increase in magnitude such as was evidenced with the more dilute solutions. The equilibrium or asymptotic values of the formaldehyde vapour pregsures that is the constant values reached when the pawage of a sufficient volume of air through the solutions had brought about apparent equilibrium *conditions between the liquid and vapour phases are given in Table I together with the corresponding concentrations of formaldehyde vapour in the effluent air.TABLE I. Gms. of formaldehyde per 100 C.C. of Mg. of formaldehyde vapour per Iitre Partial pressure of formaldehyde formalin solution ..................... 9.52 19-7 29.5 31.1 40.2 of issuing air ........................... 0-59 1-01 1-39 1-40 1.75 vapour in mm. of mercury ......... 0.340 0.575 0.780 0.795 1-025 FIU. 3. FIG. 5. cfm. of fornaaldehyde per 100 C.C. of solution. Gms. of forma2dehyde per 100 ex. of solution. OH,O/CH,O = 0'13. The solution containing 31.1 g. of formaldehyde per 100 C.C. was exposed prior to the vapour-pressure determinations at 20" in the thermostat for a number of days ; the value given in the above table for the vapour pressure ia the mean of several almost coincident values vix.0.797 0.793 0-795 mm. of Hg which were subsequently obtained. In Fig. 3 the partial pressures of the formaldehyde vapour, expressed in mm. of mercury are plotted as ordinates against the corresponding concentrations of the aqueous formaldehyde solutions in g. per 100 C.C. as abscissae. It is seen that the partial pressure of the formaldehyde vapour is not a linear function of the formaldehyde concentration in the liquid phase (compare the relation between density and refractive index of a formaldehyde solution and the concentration of the latter a8 demonstrated by Ormandy and Craven Zoc. cit.) but that the rate of increase of the partial pressure VOL. CXXVII. 34 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR with the concentration falls off slightly with increasing concentration of the solution.Addition of 3Iethy.l Alcohol to Aqueous Formaldehyde Solutions at 20".-Pure methyl alcohol free from acetone was added to the aqueous formaldehyde solutions treated in the manner previously described in such amount that for all the solutions a constant small ratio CH,O/CH,O vix. 0-13 by weight was preserved. As in the case of the purified aqueous formaldehyde solutions there was again for certain solutions a rise in t,he vapour pressure values until maximum values were attained. Litres of air passed through formaldehyde solutions. A comparison of the curves in Fig. 2 with those in Fig. 4 shows the effects of addition of small quantities of methyl alcohol to aqueous f ormnldehyde solutions. The partial pressure values at the outset approximate more closely to the final maximum values than is the case with uncontaminated formaldehyde solutions ; the apparent equilibrium vapour pressures are raised in all cases above those previously determined ; and the difference of vapour pressure due to increase in the formaldehyde concentration of tlhe solution is more pronounced in this series of determinations.Table I1 gives the apparent equilibrium values of the partial pressures of these formalin solutions together with the corresponding concen PRESSURES OF AQUEOITS SOLUTIOPU'S O F FORMALDEHYDE. 35 trations of formaldehyde vapour in the effluent air. The curve (Fig. 5) shows diagrammatically the relation of the partial pressure of the formaldehyde vapour to the formaldehyde concentration of the solution.TABLE Ir. Gms. of formaldehyde per 100 C.C. of formalin solution. CH,O/CH,O = Ng. of formaldehyde vapour per litro of Partial pressure of f ormzldehyde vapour 0.13 .......................................... 9-22 19.1 28.3 37.5 issuing air ................................. 0.62 1.29 1-86 2.32 in mm. of Hg .............................. 0.362 0.760 1.0s 1.31 When the forrnaldehyde-content of the solution is expressed in g. per 100 c.c. there is a nearer approach in this case to a straight line relationship between formaldehyde-concentration and the corresponding partial pressure of formaldehyde vapour. There is a strill nearer approach to a 'linear relationship when the forznalde-hyde-concentration is expressed as g. per 100 g.of solution since the specific gravities of forrnalin solutions increase with concen-tration t'he value for a 40y0 solution being about 1-0s. Formaldehyde Vapoiir I't't?sswes of Aqueous Formaldehyde Solutions a t 0". Formalin solutions freed from methyl alcohol were allowed to stand at the ordinary temperature for several days and subsequently introduced into the '' carburettors " (two in series were employed in these experinients at 0"). Prior to the vapour-pressure determin-ations the " carburettors " w-ere left in the thermostat over-night at 0". With each of the solutions examined as increasing volumes of air were passed the partial vapour pressures decreased fairly rapidly at first and then more slowly reached an almost constant miriimum value. It will be remembered that the partial vapour prcssure rose to an approximately constant maximum value when a purified formalin solution after standing for a short period at 15" was introduced into a thermostat a t 20" and air passed for the purpose of determining its partial f ornialdehydc vapour pressure at tJhat temperature.The accompanying curves A B C and D of Fig. 6 show graphically the manner in which the partial formaldehyde vapour pressures of the solutions decrease as increasing volumes of air are passed. Thc a p p r m t cynilibrium Td1ies o€ the formaldehyde vapour pressures that is the constant minimum values reached when the passage of a sufficient volume of air through the solutions has c 36 BLAIR AND LEDBURY THE PAFLTIAL FORMALDEHYDE VAPOUR brought about apparent equilibrium conditions between liquid and vapour phmes are given in Table 111 together with the correspond-ing concentrations of formaldehyde vapour in the effluent air.In the case of a formaldehyde solution containing 16 g. of formaldehyde per 100 c.c. which had been exposed at 0" in the thermostat for 13 da$s before the passage of air partial pressure values were obtained which were constant from the commencement ; vix., 0.104 0.100 0.102 mm. of Hg. The mean of these values falls very closely to the curve in Fig. 7. FIG. 6 . Litres of air passed through formaldehyde solzrtions. TABLE 111. Gms. of formaldehyde per 100 C.C. of Mg. of formaldehyde vapour per litre of Partial pressure of formaldehyde vapour formalin solution ........................8.09 15.68 20.63 31.25 issuing air ................................. 0.095 0.166 0.201 0.265 in mm. of Hg .............................. 0.056 0.102 0.118 0.157 From the data provided in Table I11 and from the curve of Fig. 7, it is evident that the partial formaldehyde vapour pressure is not a linear function of the concentration of the solution but that increase in partial pressure with concentration is less pronounced at 0". For the purpose of comparing the partial formaldehyde vapour-pressure values at 0" with those previously determined at 20" the curves A and B are given in Fig. 8. A is the partial formaldehyde vapour-pressure-solution-concentration curve for O" and B the corresponding curve plotted on the same scale for 20". For reasons cited above it was not possible to study the vapour-pressure charac-teristics of formalin solutiom much above 30% in strength.The ratio Pressure of formaldehyde vapour a t O"/Pressure o PRESSURES OF AQUEOUS SOLUTIONS OF FORMALDEHYDE. 37 formaldehyde vapour at 20" varies progressively from 0.18 for a solution containing 30 g. of formaldehyde per 100 C.C. to 0.22 for a solution containing 5 g. of formaldehyde per 100 c.c. whilst the ratio Pressure of aqueous vapour a t O"/Bressure of aqueous vapour at 20" = 4*53/17.4 = 0.28. From these values it appears it is possible to obtain a more con-centrated formalin solution by chilling warm air or gas containing water vapour and formaldehyde vapour to O" than by cooling the same gas to 20". In such a process the difference of solution strength a t the two temperatures would be more pronounced in the case of the more concentrated vapours.FIG. 7. ma. 5. Gm8. of formaldehyde per 100 C.C. of Gms. of formaldehyde per 100 C.C. of solution. solution. Addition of Methyl Alcohol to Aqueous Formaldehyde Xolutions at ()".-To aqueous formaldehyde solutions methyl alcohol free from acetone was added in such amount tthat the ratio WtCH,Q/WtCH2Q =0.13 this being the ratio employed in the corresponding vapour-pressure determinations at 20". The data obtained for the solutions studied indicated that the addition of small amounts of methyl alcohol to aqueous formaldehyde solutions had very little effect on the &a1 formaldehyde partial vapour pressure values of such solutions.Thus from the curve (Fig. 7) it is seen that the vapour pressure of an aqueous solution containing lO.8 g. of formaldehyde per 100 C.C. in the absence of methyl alcohol is very approximately equivalent to 0.87 mm. of mercury. This value is almost identical with that obtained with a solution of corresponding strength containing a littl 38 BLAIR AND LEDBURY THE PARTIAL FORMALDEHYDE VAPOUR methyl alcohol (CH,O/CH,O = 0.13 by weight) wix. 0.072 mm. of mercury. The divergence between the initial and final values is not so pronounced as in the previous instance. Discussion of Results. Aqueous formaldehyde solutions do not exhibit the characteristic properties of gas-water systems but on the contrary at the ordinary temperature behave from the point of view of partial vapour pressures in a manner suggestive of solutions in water of a soluble liquid of comparatively high boiling point e.g.glycerol in water. Determinations of the apparent molecular weight of formaldehyde in its aqueous solutions as well as the vapour tension characteristics of these solutions indicate the existence in the dissolved state of complex molecules in addition to the simple molecules of formal-dehyde. The heavier molecules of the solute may include not only one or more polymerides of formaldehyde but also products com-plex or otherwise derived as a result of hydration of the formal-dehyde ; consideration of the distinctive properties of aqueous formaldehyde solutions and evidences of the residual affinity exerted by the simple formaldehyde molecule by reason of its doubly linked oxygen atom render such a postulate feasible.A possible interpretation of the conditions existing in an aqueous formaldehyde solution may be symbolically represented as follows :-complex -+ CB,O [Formaldehyde] hydrated etc . .t- (simple molecules). Assuming the representation provides a reasonable although vague conception of the equilibrium conditions within the solution, then from apparent molecular-weight determinations vapour-pressure considerations etc. the equilibrium a t the ordinary temperature must correspond to a large excess of the heavier molecules. The partial pressure at a particular temperature of the formaldehyde vapour above an aqueous formaldehyde solution will be almost entirely dependent on the concentration of the simple molecular form of the aldehyde since the heavier molecules will possess a low volatility in view of tlheir relatively high molecular weights.When a formaldehyde solution which had been treated for the removal of methyl alcohol was introduced into a thermostat main-tained at 20° after previously standing for several days at 15" and air was bubbled through the solution as in the above determinations, there was an increase of the formaldehyde vapour pressure to a constant maximum value as increasing volumes of air were passed. Air passing through the solution at any particular moment takes u PRESSURES OF AQUEOUS SOLUTIONS OF FORMALDEHYDE. 39 formaldehyde vapour in amount corresponding to the concentration of simple formaldehyde molecules.It is assumed that the new equilibrium conditions between the complex and the simple molecules in solution brought about by raising the temperature is only gradually approached as time elapses but that the velocity of this approach or in other words the amount of simple formaldehyde produced in unit time a t 20" by the transformation of the complex, is greater than the rate of removal of formaldehyde from solution under the influence of its vapour pressure; this vapour pressure being a function of the concentration of the simple molecular form of the aldehyde. Since the velocity of transformation is initially greater than that of removal simple formaldehyde will accumulate at this temperature in excess of its original concentration. This accumulation of the simple form will exert a two-fold influence ; fist by reason of its active mass in solution it will lower the velocity of transformation of the complex and secondly it will increase the velocity of the removal of formaldehyde from solution since the latter is dependent on the concentration of the simple molecular form.I n the course of time the two velocities will be equalised and the amount of formaldehyde vapour removed a t 20" by the passage of air from the solut'ion in a given time will reach a constant maximum value. The gradual attainment of constant values by the formaldehyde vapour pressures a t 0" can also be explained by the gradual read-justment of the equilibrium conditions between complex and simple molecules in solution necessitated by change of t,emperature.A formaldehyde solution which had been exposed for several days a t Z O O , prior to determinations a t 20" being carried out provided a series of vapour pressure values which were almost constant from the outset. These values corresponded with a point lying very close to the curve of Fig. 3. A similar procedure in the case of a solution a t 0" made i t evident that in this case also the equilibrium condition had been brought about by prolonged exposure a t the temperature under consideration. The latter observations lend support to the hypo-thesis put f oi-ward in explanation of the variations involved. The addition of a small amount (CH,O,/CH,O = 0.13) of methyl alcohol to an aqueous formaldehyde solution not only brings about, a t Z O O a nearer approach of the vapour pressure determined a t the outset to those determined after the passage of large volumes of air, but also produces a considerable increase (0.60 to 0-80 mm.of Hg for a solution containing 20 g. of CH,O per 100 c.c.) in the constant maximum values eventually at'tained. At 0" the equilibrium vapour pressure values were affected only very slightly by the addition oE small amounts of methyl alcohol. In the course of 40 VALTON THE DETECTION OF METHYLAMINE further investigation the results of which i t is hoped to publish at a later date i t was found that the partial formaldehyde vapour pressure of a 15% methyl-alcoholic solution of formaldehyde at 20" was more than double that of an aqueous solution of corre-sponding strength. This would explain the relatively high values found for the formaldehyde vapour pressures of formalin solutions containing methyl alcohol including solutions of commercial f ormalin , Summary. The partial formaldehyde vapour pressures of aqueous formalde-hyde solutions freed from methyl alcohol have been determined at 20" and 0" by the " dynamic " method. After an initial exposure of a solution at 15" an increase of the partial pressure values as increasing volumes of air were passed until the subsequent attainment of a constant maximum value was noted at Z O O whilst a t 0" the continuous passage of air through a solution was shown to bring about a lowering of the partial formalde-hyde vapour pressure until a constant minimum value was reached. The addition of methyl alcohol to an aqueous formaldehyde solution decreases the divergence between the initially and finally observed values of the partial formaldehyde vapour pressures and, in the case of solutions at 20" enhances the constant maximum value eventually obtained. Under these latter conditions there is a nearer approach to a linear relationship between formaldehyde partial vapour pressure and concentration. An hypothesis has been put forward to explain certain of the observations made. Further investigations are being made on the properties of aqueous and methyl-alcoholic solutions of formaldehyde. This work was carried out for the Chemistry Research Board of the Department of Scientific and Industrial Research to whom we are indebted for permission to publish these results. MAIN LABORATORY R.N. CORDITE FACTORY, HOLTON HEATX DORSET. [Received September 9th 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700026

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

J O U R N A L OF THE CHEMICAL SOCIETY. Qontltti-tfrt of @ttblicHtiou: C7mimu;cn N. V. SIDGWICK M.A. Sc.D. F.R.S. H. B. BUCW C.B.E. D.Sc. F.R.S. E. C. C. BALY C.B.E. F.R.S. H. BASSETT D.Sc. Ph.D. 0. L. BBADY D.Sc. A. W. CROSSLEY C.H.G. C.B.E., F. G. DONNAN C.B.E. M.A. F.RS. H . T . DUDLEY O.B.E. M.Sc. Ph.D. U. R. EVANS M.A. J. J. Fox O.B.E. D.Sc. C. S.GIBSON O.B.E. M.A. A. J. GBEENAWAY F.I.C. I. M. HEILBBON D.S.O. D.Sc. T. A HENRY D.Sc. F.R.S. C. E. INGOLD D.Sc. F.R.S. H. MCCOMBIE D.S.O. M.C. D.Sc. J. I. 0. M A ~ O N M.B.E. D.Sc. W. H. MILLS Sc.D. F.R.S. T. S. MOOEE X A . B.Sc. G. T. MORGAN O.B.E. D.Sc. F.R.S. J. R PARTINGTON M.B.E. D.Sc. J. C. PHILIP O.B.E. D.Sc. F.R.S. R. H. PICKABD D.Sc. F.BS. T. S. PBICE O.B.E. D.Sc. F.B.S. F. L. PYMABN D.Sc. F.R.S. J.F. THORPE C.B.E. D.Sc. F.B.S. W. P. WYNNE D.Sc. F.R.S. $bitor: CLARENCE SMITH D.Sc. Jrrbexer : MARGARET LE PLA BSc. 1925. VOL CXXVII. Part II. pp. 1493-end. LONDON: GURNEY & JACKSON 33 PATERNOSTER ROW E.C. 4. 1925 PRINTED IN GREAT BRITAIN BY R r c w CUY & SONS LIMITED, BUNGAY SUFFoL

ISSN:0368-1645    

DOI:10.1039/CT92527FP037

出版商:RSC    

年代:1925

数据来源: RSC

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40 VALTON THE DETECTION OF METHYLAMINE VI.-The Detection of Methylamine in Presence of Excess of Ammonia. By P. A. VALTON. A CONVENIENT method for the differentiation of methylamine and ammonia depends on the much greater reactivity of the former with 2 4-dinitrochlorobenzene ; the product 2 4-dinitromethyl 'IN PRESENCE OF EXCESS OF AMMONIA. 41 aniline is very sparingly soluble in alcohol readily cryst&llised, and easily identifiable melts sharply at 175.5" and depresses the m. p. of 2 4-dinitroaniline (179"). The method can be used for detecting small quantities of methylamine in presence of excess of ammonia. When a dilute alcoholic solution of dinitrochlorobenzene is treated with ammonia at the ordinary temperature no dinitro-aniline separates after 20 hours although the solution slowly becomes yellow; on the other hand with methylamine the yellow colour develops rapidly and after 18 to 20 hours dinitromethyl-aniline crystallises out.The smallest quantities of methylamine hydrochloride which could be identified by this means were 0.005 g. when alone and 0.008 g. 0.01 g. and 0.02 g. in presence of 0.08 g., 1 g. and 20 g. respectively of ammonium chloride. Dimethyl-amine interferes but the method is still applicable if the amount of dimethylamine does not exceed 10% of the methylamine. The minimum quantity of methylamine hydrochloride which could be identified was 0.02 g. in presence of 0.2 g. of ammonium chloride and 0.002 g. of dimethylamine hydrochloride and 0.04 g. in presence of 4 g. of ammonium chloride and 0.004 g.of dimethylamine hydrochloride. The method employed was as follows. The solution containing the methylamine and ammonium salts was introduced into a 250 C.C. flask with Kjeldahl splash-trap and 30 C.C. oE 2N-sodium hydroxide were added together with enough water to bring the volume up to 80 C.C. The mixture was distilled into 10 C.C. of a, 0.5% alcoholic soIution of 2 4-dinitrochlorobenzene in a graduated tube the adapter of the condenser dipping nearly to the bottom. When the volume of the solution had reached 20 c.c. the distillation was stopped and the solution left for 20 hours. The precipitated dinitromethylaniline was crystallised once from alcohol and identified by the method of mixed melting points. When the minimum amount of methylamine was used the amount of precipitate was sometimes too small for crystallisation but the crude product after being washed with a little alcohol melted above 170" and on admixture with dinitromethylaniline between 170" and 175".When there was but 0.02 g. of methylamine hydro-chloride mixed with 20 g . of ammonium chloride the former was concentrated by evaporating the solution to dryness extracting the dry salt with 50 C.C. of hot alcohol and using this extract in the distillation. UNIVERSITY COLLEGE LONDON. [Received July loth 1924.1 c 40 VALTON THE DETECTION OF METHYLAMINE VI.-The Detection of Methylamine in Presence of Excess of Ammonia. By P. A. VALTON. A CONVENIENT method for the differentiation of methylamine and ammonia depends on the much greater reactivity of the former with 2 4-dinitrochlorobenzene ; the product 2 4-dinitromethyl 'IN PRESENCE OF EXCESS OF AMMONIA.41 aniline is very sparingly soluble in alcohol readily cryst&llised, and easily identifiable melts sharply at 175.5" and depresses the m. p. of 2 4-dinitroaniline (179"). The method can be used for detecting small quantities of methylamine in presence of excess of ammonia. When a dilute alcoholic solution of dinitrochlorobenzene is treated with ammonia at the ordinary temperature no dinitro-aniline separates after 20 hours although the solution slowly becomes yellow; on the other hand with methylamine the yellow colour develops rapidly and after 18 to 20 hours dinitromethyl-aniline crystallises out. The smallest quantities of methylamine hydrochloride which could be identified by this means were 0.005 g.when alone and 0.008 g. 0.01 g. and 0.02 g. in presence of 0.08 g., 1 g. and 20 g. respectively of ammonium chloride. Dimethyl-amine interferes but the method is still applicable if the amount of dimethylamine does not exceed 10% of the methylamine. The minimum quantity of methylamine hydrochloride which could be identified was 0.02 g. in presence of 0.2 g. of ammonium chloride and 0.002 g. of dimethylamine hydrochloride and 0.04 g. in presence of 4 g. of ammonium chloride and 0.004 g. of dimethylamine hydrochloride. The method employed was as follows. The solution containing the methylamine and ammonium salts was introduced into a 250 C.C. flask with Kjeldahl splash-trap and 30 C.C.oE 2N-sodium hydroxide were added together with enough water to bring the volume up to 80 C.C. The mixture was distilled into 10 C.C. of a, 0.5% alcoholic soIution of 2 4-dinitrochlorobenzene in a graduated tube the adapter of the condenser dipping nearly to the bottom. When the volume of the solution had reached 20 c.c. the distillation was stopped and the solution left for 20 hours. The precipitated dinitromethylaniline was crystallised once from alcohol and identified by the method of mixed melting points. When the minimum amount of methylamine was used the amount of precipitate was sometimes too small for crystallisation but the crude product after being washed with a little alcohol melted above 170" and on admixture with dinitromethylaniline between 170" and 175". When there was but 0.02 g. of methylamine hydro-chloride mixed with 20 g . of ammonium chloride the former was concentrated by evaporating the solution to dryness extracting the dry salt with 50 C.C. of hot alcohol and using this extract in the distillation. UNIVERSITY COLLEGE LONDON. [Received July loth 1924.1 c

ISSN:0368-1645    

DOI:10.1039/CT9252700040

出版商:RSC    

年代:1925

数据来源: RSC

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42 GIBSON NITRO-DERIVATIVES OF 0-CRESOL. V11.-Nitro-derivatives of o-Cresol. By GEORGE PHILIP GIBSON. THE direct nitration of o-cresol has been studied by many chemists ; the chief products are 3-nitro-o-cresol and 5-nitro-o-cresol although Spiegel Munblit and Kaufmann (Ber. 1906 39 3240) record the formation of a little 3 5-dinitro-o-cresol (compare Hofmann and Millar Ber. 1881,14,568 ; Rapp Annulen 1884,224 175 ; Schultz, Ber. 1907 40 4319; Wieland Bernheim and Bohm Ber. 1921, 54 1776) ; all workers have given the melting point 70" for 3-nitro-o-cresol but the recorded melting point of 5-nitro-o-cresol ranges from 79" to 95". The author has attempted to elucidate these discordant results, although his main object has been the investigation of certain derivatives of 3-nitro-o-cresol which were required for another research.The greater part of the material used was prepared by Hofmann and Millar's method although Schultz's procedure proved to be the best for mononitration owing to the ease with which the temperature and concentration can be regulated. Using the first method if 3- and 5-nitro-o-cresols are the desired products the conditions of nitration must be carefully adhered to Otherwise 3 5-dinifro-o-cresol may be the main product of the reaction. The fact that pure 5-nitro-o-cresol is dimorphous and the presence of 3 5-dinitro-o-cresol and of tarry materials in the residue after the removal of the 3-nitro-o-cresol render the isolation of 5-nitro-0-cresol somewhat troublesome ; although these difficulties have been overcome the yield is poor.5-Nitro-o-cresol forms a monohydrate melting a t 3 0 4 0 " (Neville and Winther Ber. 1582 15 2975) which possesses properties very different from those of otherwise similar nitrocresols which are anhydrous ; crystallisation from aqueous solvents is therefore an excellent method for removing 3 5-dinitro-o-cresol from 5-nitro-o-cresol. Anhydrous 5-nitro-o-cresol crystallises in two forms which are interconvertible. One the pale yellow unstable form which separates first passes when i t is left in the presence of solvents, crushed or rubbed into the more stable colourless variety. Previous workers have usually obtained derivatives of the above-named nitro-o-cresols by the nitration of the tolyl ethers and esters (Hofmann and Rlillar Zoc.c i t . ; Borsche Ber. 1923 56 1488; Stadel ,4nnalen 1883 217 155; Reverdin Ber. 1902 35 1444; 1912 45 1450). In all cases the orientation of the nitro-group is not certain and the structures of a number of these derivatives hav GIBSOX RITRO-DERIVATIVES O F 0-CRESOL. 43 therefore been established by preparinS the compounds directly from pure 3- and 5-nitro-o-cresols and from 3 5-dinitro-o-cresol (compare Ullmann and Sank Ber. 1911 44 3730 ; Cain and Simon-sen J. 1914 105 156; Spiegel Munblit and Kaufmann Zoc. cit. ; Hofmann and Millar Zoc. cit.). I n the case of derivatives of 5-nitro-0-cresol ordinary methods give excellent yields but with 3-nitro- and 3 5-dinitro-o-cresol, probably owing to the presence of two groups ortho to the reacting hydroxyl group poor results are obtained even when the temper-ntnre is raised and the time prolonged.For the preparation of derivatives other than the acetates (Smit!] and Orton J. 1908 93 1250) the dry sodium salts of 3-nitro- and 3 Sdinitro-o-cresol were heated at high temperatures with benzoyl chloride toluene-p-sulphonyl chloride methyl sulphate and methyl toluene-p-sulphonate respectively (compare Hofmann aiid Millar, Zoc. cit.; Cain and Simonsen J. 1914 105 156). The yields were satisfactory and the reactions took place in two directions the proportions of the products depending on the nature of the reagent. I n the case of benzoyl chloride and toluene-p-sulphonyl chloride, t h e products were chiefly the corresponding benzoates and toluene-psulphonates with very sniall proportions of the corresponding chloronitrotoluene or chlorodiiiitrotoluene (compare Ullmann and Ssn6 Zoc.cit.). I n the experiments with methyl sulphate and sodium 3-nitro-o-tolyl oxide the purity of the reagent seems to be the determining factor. Using pure niethyl sulphate the yield of the methyl ether is nearly theorctical but if methyl hydrogen sulphate is present very serious complications arise aiid the yield inay fall below 50% ; sulphonic derivatives of 3-nitro-o-cresol and its methyl ether are produced with appreciable charring the small amount of impurity (10 yo in commercial methyl sulphate) acting as an intermediary according to the equation n.here R is NO,*C,H,Me*OH (1) or NO,~C,H,Xe*OMe (11) (compare C. S. Gibson and Vining J.1923 323 S40 ; Simon and FrGrejacque, Cornpt. wad. 1923 176 900). In the casc of 3 5-dinitro-o-cresol methylation takes place quantitatively in either of the above cases because the 5-position is occupied so that sulphnnic derivatives cannot readily be formed ; using methyl or ethyl toluene-p-sulphonate with the above dry sodium salts good yields of the Corresponding ethers are easily obtained. R*H + OPI*SO,~UMe -4 R*XO,*OJ4e + H,O, c* 44 GIBSON NITRO-DERIVATIVES OF 0-CRESOL. E X P E R I M E N T A L. Preparation of 3- and 5-Nitro-o-cresols.-A mixture of nitric acid (107 c.c.; d 1.42) and glacial acetic acid (300 c.c.) was stirred in a freezing mixture a t - 15" while a mixture of o-cresol (100 g.) and glacial acetic acid (100 c.c.) was added in the course of 2 hours when a thick magma of crystals separated.After standing 2 hours in the freezing mixture the mass was poured into water (5000 c.c.), the crystals were separated and submit'ted to steam distillation, when crude 3-nitro-o-cresol (yield 35%) containing a small pro-portion of 3 5-dinitro-o-cresol passed over ; 5-nitro-o-cresol mixed with a little (10%) 3 5-dinitro-n-cresol then remained in the flask as an oil which solidified when cold. The crude distillate m. p. 55-65" was fractionally distilled in steam and the various fractions were crystallised from petroleum (b. p. 80-looo). The first fractions gave deposits of deep yellow plates of nearly pure 3-nitro-o-cresol ; the last gave pure 3 5-dinitro-o-cresol in well-defined colourless prisms.The 3-nitro-compound may also be isolated by the crystallisation of the crude sodium salt from water. Pure 3 nitro-o-cresol has b. p. 102-103"/9 mm. and m. p. 70". The residue from the steam distillation was cryst'allised from a large quantity of 50% alcohol when crude 3 5-dinitro-o-cresol was deposited the 5-nitro-o-cresol remaining in solution. The filtered solution was evaporated and the dark oily residue purified by dis-tillation (b . p. 186-1 90"/9 mm .) by distillation in superheated steam at 180° or by crystallisation of the sodium salt from water; in the last two cases the monohydrate was dried at 100" and the anhydrous compound crystallised from a dry solvent such as benzene. Anhydrous 5-nitro-o-cresol is deposited from a hot benzene solu-tion in h e yellow needles which when left in the mother-liquor for a day or two redissolve and crystallise again in large colourless plates; the change takes place slowly from one or two centres of crystallisation so that the line.of advance of the transformation is quite distinct throughout the process. On attempting to separate the needles by filtration they immediately fall to powder when touched or pressed and are transformed into the plates with the correct melting point. With great care the needles may be isolated and they remain clear for a short time but eventually become opaque. Similar phenomena to the above occur in other solutions with more or less rapidity but are most characteristic in benzene. Owing to the readiness with which the unstable form is converted into the stable both seem to melt a t 96"; if great care is taken to procure the needles unchanged the melting point is sometimes as low as 75" but it depends on the rapidity of the heating GIBSOPJ NITRO-DERIVATIVES OF 0-CRESOL.45 On crystallisation from aqaeous alcohol or acetone 5-nitro-o-caresol is deposited in very fine needles of the mono-hydrate I-. 13. 30-40" as stated by Neville and Winther (Ber. 1882 15 2973). Preparation of 3 5-Binitro-o-cresol.-A mixture of nitric acid (150 c.c.; d 1-42) and glacial acetic acid (300 c.c.) was cooled in ice m d mechanically stirred while a solution of o-cresol(lO0 g.) in glacial acetic acid (100 c.c.) was gradually added. After standing at the ordinary temperature for 24 hours the product was poured into water the granular solid separated and distilled in steam to remove a small amount of crude 3-nitro-o-cresol (~7ield 10:h).The residue in the flask was chiefly 3 5-&nitro-o-cresol with some 5-nitro-o-crcsol (loo/) and tarry materials. After crystallisation from 50y0 alcohol (p. 44) the (lark brown 3 5-dinitro-o-crcsol was converted into the sodium salt when the colouring matter remained in the mother-liquor and the pure salt was obtained. Pure 3 5-dinitro-o-cresol is slightly volatile in steam (3 g. per litre) and can be recrystallised from 50% aqueous alcohol or petrol-eum (b. I>. GO-SOo). T h e Xodimz 8aZts.-As the sodium salts of the nitro-o-cresols are fairly readily solublc in water and appear t o hydrolyse during the process of drying a t 100° they are best prepared in the pure state by treating a suspension of sodium ethoside in boiling benzene with a benzene solution oE a slight excess of the nitro-compound; the products are separated and washed with dry benzene.Sodium 3-nitro-o-tolyl oxidc crystallisea froin water in deep red plates (+ 2H,O) ; at loo" i t sinters and then gives the anhydrous compound as a light brick-led powder (Prazer ilmer. Chem. J . , 1903 30 309). Sarupk prepared with sodium ethoxide (Found : Xa = 13.10. Calc. for C,H,O,NNa ISa = 13.14%). Sodium 3-nitro-o-to13Z oxide crystallises from water in yellow, hytirated needles which at 100" without sintering give a beautiful cerise anhydrous salt. Specimen prepared with sodium ethoxide Sodium 3 5-dinitro-o-tolyl oxide forins a deep yellow solution and crxstallises in yellow hydrated needles which without softening at loo" give a deep brick-red powder.Specimen dried at 100" (Found Na = 10.5,. l'yricline 3 5-dinitro-o-toh~Z oxide C1,H1105N, separates in orange needles when a solution of 3 5-dinitro-o-cresol (2 g). in a hot mistilre of pyridinc (2 g.) and benzene (10 c.c.) is cooled. It melts at 96" 2nd gradually dissociates in the air and in solution but i t can Lc recrystallised from dry solvents containing a little pyridine (Found C == 52.2 ; H = 4-1. CI2H,,O5N3 requires C = 52.0 ; (FOU~IC~ Ka = 1 3 . 1 3 ~ ~ ) . C7H5O5N2N% requires Na = 10-460/,). 11 = 4*Q(',LJ) 46 GIBSON NITRO-DERIVATIVES OF 0-CRESOL. The Acetyl Derivatives.-5-Nitro-o-tolyZ acetate N02*C,H3Me*OAc, was formed by the action of acetic anhydride on pure 5-nitro-0-cresol in dry pyridine at the ordinary temperature.After 12 hours, the solution was diluted with water extracted with ether and the extract shaken with dilute acid and then with dilute sodium hydroxide solution. The ether was evaporated and the solid residue crystallised from a mixture of petroleum (b. p. 80-100") and acetone (large prisms) or from alcohol (needles). This ester m. p. 88" is readily soluble in acetone benzene or chloroform but sparingly soluble in alcohol carbon tetrachloride, or light petroleum (Pound C = 55-3; H = 4.6. C,H,O,N requires C = 554; H = 4.6%). 3-Nitro-o-toZyl acetate was prepared by treating pure 3-nitro-0-cresol (5 g.) at the ordinary temperature with acetic anhydride (15 c.c.) containing a trace of concentrated sulphuric acid (Smith and Orton Zoc.cit.) until the yellow colour of the nitrocresol had disappeared ; water was added the oily ester extracted with ether, the extract washed with dilute caustic soda and evaporated; the residue crystallised from alcohol in large tablets m. p. 42". This acetate is readily soluble in the ordinary organic solvents and crystallises well from alcohol or petroleum (b. p. 60-80") (Found : 3 5-Dinitro-o-tolyl metate C,H,Me(??O,),*OAc prepared in a similar manner melts a t 96" and crystallises readily from alcohol. It is fairly soluble in alcohol acetone benzene or chloroform but sparingly soluble in petroleum (b. p. 60-80") or carbon tetrachloride (Pound C = 4443; M = 3.4. C,H,O,N requires C = 45.0; C = 55.4 ; H = 4-57:).H = 3.3:/,). The Benxoyl Deri~atives.-5-~Yitro-o-tolyl benzoate, N02*C6H3h~e*OBz , was prepared in the same way as the corresponding acetate (above), a slight excess of pure benzoyl chloride being used in place of acetic anhydride. It melts at 128" is sparingly soluble in ether alcohol or light petroleum and fairly soluble in acetone benzene chloroform or carbon tet,rachloride (Found C = 65-3; H = 4-3. C,,H,,O,N requires C = 65.4; H = 4.28:/,). 3-Nitro-o-tolyl benzoate was obtained by heating anhydrous sodium 3-nitro-o-tolyl oxide (p. 45) with pure benzoyl chloride (2 mols.) for 1 hour at 120". The product was treated in the cold with a mixture of pyridine water and ether ; the ethereal solution was shaken successively with acid and with dilute alkali and finally evaporated ; the residue crystallised from alcohol or petroleum (b.p. SO-80") in needles m. p. 42" b. p. 215-220"/9 mm. Thi GIBSON NITRO-DERIVATIVES OF O-CRESOL. 47 ester is soluble in the usual organic solvents with the exception of petroleum (b. p. S0-8O0) (Pound C = 65.4; I3 = 4.2%). 3 5-~initro-o-fdyl benzoate C,H,Me(NO,),*O~z m. p. 132", prepared in a similar manner from sodium 3 5-djnitro-o-tolyl oxide, crystallises readily from acetone alcohol or benzene ; it is sparingly soluble in alcohol etcher or light petroleum but easily soluble in acetone benzene chloroform or carbon tetrachloride (Found c = 55-7 ; H = 3.4. = 3.3%). The Toluene-p-sulphonyl Derivatives.-5-Nitro-o-tolyl tokuene-p-sulphomte ~030C6H3~~e*O*So~*c7H7 obtained as in the case of the corresponding benzoate (p.Q6) using toluene-p-sulphonyl chloride, crystallises from alcohol petroleum (b. p. 60-80°) or carbon tetrachloride in indefinite plates m. p. 107". It is sparingly soluble in alcohol or light petroleum but fairly soluble in acetone benzene, chloroform or carbon tetrachloride (Pound S = 10-5. C14H130,NS requires S = 10.4:/,). 3-Nitro-o-tolyl toluene-p-sulphonate was prepared by treating sodium 3-nitro-o-tolyl oxide (1 mol.) with pure tolaxene-p-sulphonyl chloride (2 mols.) * the conditions and method of isolation were the same as those described in the case of t h e benzoate (p. 46). The compound melts at 66" and boils at 257"/11 mm. with decom-position but distils unchanged a t 205-.210"/0~5 mm.; it crystallises well from alcohol in which it is sparingly soluble and dissolves freely in acetone benzene chloroform or carbon tetrachloride (Found S = 10.2%). The corresponding toluene-p-sulphonate from 3 5-dinitro-o-cresol which has already been isolated by Ullmann and San6 (Ber. 1911 44 3730) can be prepared in a similar manner. 3-Nitro-o-chlorotoluene is formed in very small quantities by the action of benzoyl or toluene-p-sulphonyl chloride on sodium 3-nitro-o-tolyl oxide and can be isolat,ed by steam distillation of the crude reaction mixture when a pale yellow pleasant-smelling oil passes over (compare Holleman Bee. trczv. chim. 1908 27 456). I n a similar manner sodium 3 5-dinitro-o-tolyl oxide yields the corresponding 3 5-dinitro-o-chlorotoluene (m.p. 63") which was oxidised to 3 5-dinitro-o-chlorobenzoic acid (m. p. 238"). The Methyl Ethers.-5-Nitro-o-tolyl methyl ether m. p. 64" (Cain and Simonsen J. 1914,105,2390 give m. p. 62") crystallises readily in needles from alcohol or petroleum but is freely soluble in acetone chloroform carbon t'etrachloride or benzene. On ~14Hl,06N requires c = 55.6 ; * The commercial compound was dried in a vacuum at 100' and dissolved in hot petroleum (b. p. 60-80°) the tarry material filtered o f f the solvent removed and the residue distilled under reduced pressure; b. p. 138-139"/9 mm 48 WHITE LIMITS FOR THE PROPAGATION OF F U M E oxidation with boiling dilute permanganate 5-nitro-o-methoxy-benzoic acid (m. p. 150") was obtained in theoretical yield.3-Nitro-o-tolyl methyl ether was obtained by heating sodium 3-nitro-o-tolyl oxide (I mol.) at 120" with pure methyl sulphate (2 mols.) for 2 hours. The dark-coloured reaction mixture was submitted to distillation in steam the volatile oil extracted with ether and the 3-nitro-o-cresol removed with dilute alkali. The ethereal solution was evaporated the residue distilled under 10 mm. and the product (b. p. 121-122") dissolved in pet'roleum (b. p. 6O-SO0) ; a t - 15" the solution deposited 3-nitro-o-%olyl methyl ether in large needles m. p. 30". The residue from the steam distillation of the methyl ether, treated with calcium carbonate gave a mixture of calcium nitro-cresolsulphonates (p. 43) together with sodium carbonate but the acids could not be separated by the fractional crystallisation of various inorganic and organic sahs which were tried.3 5-Dinitro-o-tolyl methyl ether (m. p. 72") can be prepared under the conditions just described; the yield is good. 3-Nitro-o-tolyl methyl and ethyl ethers and the corresponding methyl and ethyl derivatives of 3 5-dinitro-o-cresol were also prepared by heat-ing the requisite dry sodium salts with methyl or ethyl toluene-p-sulphonate * in a similar manner. The yields were good and the products had the properties given in the literature. I n conclusion the author desires to express his thanks to the Department of Scientific and Industrial Research for a grant which enabled him to carry out the above work and to Professor F. S. Kipping for his kindly supervision.UNIVERSITY COLLEGE NOTTINGHAM. [Received August 29th 1924. 42 GIBSON NITRO-DERIVATIVES OF 0-CRESOL. V11.-Nitro-derivatives of o-Cresol. By GEORGE PHILIP GIBSON. THE direct nitration of o-cresol has been studied by many chemists ; the chief products are 3-nitro-o-cresol and 5-nitro-o-cresol although Spiegel Munblit and Kaufmann (Ber. 1906 39 3240) record the formation of a little 3 5-dinitro-o-cresol (compare Hofmann and Millar Ber. 1881,14,568 ; Rapp Annulen 1884,224 175 ; Schultz, Ber. 1907 40 4319; Wieland Bernheim and Bohm Ber. 1921, 54 1776) ; all workers have given the melting point 70" for 3-nitro-o-cresol but the recorded melting point of 5-nitro-o-cresol ranges from 79" to 95". The author has attempted to elucidate these discordant results, although his main object has been the investigation of certain derivatives of 3-nitro-o-cresol which were required for another research.The greater part of the material used was prepared by Hofmann and Millar's method although Schultz's procedure proved to be the best for mononitration owing to the ease with which the temperature and concentration can be regulated. Using the first method if 3- and 5-nitro-o-cresols are the desired products the conditions of nitration must be carefully adhered to Otherwise 3 5-dinifro-o-cresol may be the main product of the reaction. The fact that pure 5-nitro-o-cresol is dimorphous and the presence of 3 5-dinitro-o-cresol and of tarry materials in the residue after the removal of the 3-nitro-o-cresol render the isolation of 5-nitro-0-cresol somewhat troublesome ; although these difficulties have been overcome the yield is poor.5-Nitro-o-cresol forms a monohydrate melting a t 3 0 4 0 " (Neville and Winther Ber. 1582 15 2975) which possesses properties very different from those of otherwise similar nitrocresols which are anhydrous ; crystallisation from aqueous solvents is therefore an excellent method for removing 3 5-dinitro-o-cresol from 5-nitro-o-cresol. Anhydrous 5-nitro-o-cresol crystallises in two forms which are interconvertible. One the pale yellow unstable form which separates first passes when i t is left in the presence of solvents, crushed or rubbed into the more stable colourless variety. Previous workers have usually obtained derivatives of the above-named nitro-o-cresols by the nitration of the tolyl ethers and esters (Hofmann and Rlillar Zoc.c i t . ; Borsche Ber. 1923 56 1488; Stadel ,4nnalen 1883 217 155; Reverdin Ber. 1902 35 1444; 1912 45 1450). In all cases the orientation of the nitro-group is not certain and the structures of a number of these derivatives hav GIBSOX RITRO-DERIVATIVES O F 0-CRESOL. 43 therefore been established by preparinS the compounds directly from pure 3- and 5-nitro-o-cresols and from 3 5-dinitro-o-cresol (compare Ullmann and Sank Ber. 1911 44 3730 ; Cain and Simon-sen J. 1914 105 156; Spiegel Munblit and Kaufmann Zoc. cit. ; Hofmann and Millar Zoc. cit.). I n the case of derivatives of 5-nitro-0-cresol ordinary methods give excellent yields but with 3-nitro- and 3 5-dinitro-o-cresol, probably owing to the presence of two groups ortho to the reacting hydroxyl group poor results are obtained even when the temper-ntnre is raised and the time prolonged.For the preparation of derivatives other than the acetates (Smit!] and Orton J. 1908 93 1250) the dry sodium salts of 3-nitro- and 3 Sdinitro-o-cresol were heated at high temperatures with benzoyl chloride toluene-p-sulphonyl chloride methyl sulphate and methyl toluene-p-sulphonate respectively (compare Hofmann aiid Millar, Zoc. cit.; Cain and Simonsen J. 1914 105 156). The yields were satisfactory and the reactions took place in two directions the proportions of the products depending on the nature of the reagent. I n the case of benzoyl chloride and toluene-p-sulphonyl chloride, t h e products were chiefly the corresponding benzoates and toluene-psulphonates with very sniall proportions of the corresponding chloronitrotoluene or chlorodiiiitrotoluene (compare Ullmann and Ssn6 Zoc.cit.). I n the experiments with methyl sulphate and sodium 3-nitro-o-tolyl oxide the purity of the reagent seems to be the determining factor. Using pure niethyl sulphate the yield of the methyl ether is nearly theorctical but if methyl hydrogen sulphate is present very serious complications arise aiid the yield inay fall below 50% ; sulphonic derivatives of 3-nitro-o-cresol and its methyl ether are produced with appreciable charring the small amount of impurity (10 yo in commercial methyl sulphate) acting as an intermediary according to the equation n.here R is NO,*C,H,Me*OH (1) or NO,~C,H,Xe*OMe (11) (compare C.S. Gibson and Vining J. 1923 323 S40 ; Simon and FrGrejacque, Cornpt. wad. 1923 176 900). In the casc of 3 5-dinitro-o-cresol methylation takes place quantitatively in either of the above cases because the 5-position is occupied so that sulphnnic derivatives cannot readily be formed ; using methyl or ethyl toluene-p-sulphonate with the above dry sodium salts good yields of the Corresponding ethers are easily obtained. R*H + OPI*SO,~UMe -4 R*XO,*OJ4e + H,O, c* 44 GIBSON NITRO-DERIVATIVES OF 0-CRESOL. E X P E R I M E N T A L. Preparation of 3- and 5-Nitro-o-cresols.-A mixture of nitric acid (107 c.c.; d 1.42) and glacial acetic acid (300 c.c.) was stirred in a freezing mixture a t - 15" while a mixture of o-cresol (100 g.) and glacial acetic acid (100 c.c.) was added in the course of 2 hours when a thick magma of crystals separated.After standing 2 hours in the freezing mixture the mass was poured into water (5000 c.c.), the crystals were separated and submit'ted to steam distillation, when crude 3-nitro-o-cresol (yield 35%) containing a small pro-portion of 3 5-dinitro-o-cresol passed over ; 5-nitro-o-cresol mixed with a little (10%) 3 5-dinitro-n-cresol then remained in the flask as an oil which solidified when cold. The crude distillate m. p. 55-65" was fractionally distilled in steam and the various fractions were crystallised from petroleum (b. p. 80-looo). The first fractions gave deposits of deep yellow plates of nearly pure 3-nitro-o-cresol ; the last gave pure 3 5-dinitro-o-cresol in well-defined colourless prisms.The 3-nitro-compound may also be isolated by the crystallisation of the crude sodium salt from water. Pure 3 nitro-o-cresol has b. p. 102-103"/9 mm. and m. p. 70". The residue from the steam distillation was cryst'allised from a large quantity of 50% alcohol when crude 3 5-dinitro-o-cresol was deposited the 5-nitro-o-cresol remaining in solution. The filtered solution was evaporated and the dark oily residue purified by dis-tillation (b . p. 186-1 90"/9 mm .) by distillation in superheated steam at 180° or by crystallisation of the sodium salt from water; in the last two cases the monohydrate was dried at 100" and the anhydrous compound crystallised from a dry solvent such as benzene.Anhydrous 5-nitro-o-cresol is deposited from a hot benzene solu-tion in h e yellow needles which when left in the mother-liquor for a day or two redissolve and crystallise again in large colourless plates; the change takes place slowly from one or two centres of crystallisation so that the line. of advance of the transformation is quite distinct throughout the process. On attempting to separate the needles by filtration they immediately fall to powder when touched or pressed and are transformed into the plates with the correct melting point. With great care the needles may be isolated and they remain clear for a short time but eventually become opaque. Similar phenomena to the above occur in other solutions with more or less rapidity but are most characteristic in benzene.Owing to the readiness with which the unstable form is converted into the stable both seem to melt a t 96"; if great care is taken to procure the needles unchanged the melting point is sometimes as low as 75" but it depends on the rapidity of the heating GIBSOPJ NITRO-DERIVATIVES OF 0-CRESOL. 45 On crystallisation from aqaeous alcohol or acetone 5-nitro-o-caresol is deposited in very fine needles of the mono-hydrate I-. 13. 30-40" as stated by Neville and Winther (Ber. 1882 15 2973). Preparation of 3 5-Binitro-o-cresol.-A mixture of nitric acid (150 c.c.; d 1-42) and glacial acetic acid (300 c.c.) was cooled in ice m d mechanically stirred while a solution of o-cresol(lO0 g.) in glacial acetic acid (100 c.c.) was gradually added.After standing at the ordinary temperature for 24 hours the product was poured into water the granular solid separated and distilled in steam to remove a small amount of crude 3-nitro-o-cresol (~7ield 10:h). The residue in the flask was chiefly 3 5-&nitro-o-cresol with some 5-nitro-o-crcsol (loo/) and tarry materials. After crystallisation from 50y0 alcohol (p. 44) the (lark brown 3 5-dinitro-o-crcsol was converted into the sodium salt when the colouring matter remained in the mother-liquor and the pure salt was obtained. Pure 3 5-dinitro-o-cresol is slightly volatile in steam (3 g. per litre) and can be recrystallised from 50% aqueous alcohol or petrol-eum (b. I>. GO-SOo). T h e Xodimz 8aZts.-As the sodium salts of the nitro-o-cresols are fairly readily solublc in water and appear t o hydrolyse during the process of drying a t 100° they are best prepared in the pure state by treating a suspension of sodium ethoside in boiling benzene with a benzene solution oE a slight excess of the nitro-compound; the products are separated and washed with dry benzene.Sodium 3-nitro-o-tolyl oxidc crystallisea froin water in deep red plates (+ 2H,O) ; at loo" i t sinters and then gives the anhydrous compound as a light brick-led powder (Prazer ilmer. Chem. J . , 1903 30 309). Sarupk prepared with sodium ethoxide (Found : Xa = 13.10. Calc. for C,H,O,NNa ISa = 13.14%). Sodium 3-nitro-o-to13Z oxide crystallises from water in yellow, hytirated needles which at 100" without sintering give a beautiful cerise anhydrous salt.Specimen prepared with sodium ethoxide Sodium 3 5-dinitro-o-tolyl oxide forins a deep yellow solution and crxstallises in yellow hydrated needles which without softening at loo" give a deep brick-red powder. Specimen dried at 100" (Found Na = 10.5,. l'yricline 3 5-dinitro-o-toh~Z oxide C1,H1105N, separates in orange needles when a solution of 3 5-dinitro-o-cresol (2 g). in a hot mistilre of pyridinc (2 g.) and benzene (10 c.c.) is cooled. It melts at 96" 2nd gradually dissociates in the air and in solution but i t can Lc recrystallised from dry solvents containing a little pyridine (Found C == 52.2 ; H = 4-1. CI2H,,O5N3 requires C = 52.0 ; (FOU~IC~ Ka = 1 3 . 1 3 ~ ~ ) . C7H5O5N2N% requires Na = 10-460/,). 11 = 4*Q(',LJ) 46 GIBSON NITRO-DERIVATIVES OF 0-CRESOL.The Acetyl Derivatives.-5-Nitro-o-tolyZ acetate N02*C,H3Me*OAc, was formed by the action of acetic anhydride on pure 5-nitro-0-cresol in dry pyridine at the ordinary temperature. After 12 hours, the solution was diluted with water extracted with ether and the extract shaken with dilute acid and then with dilute sodium hydroxide solution. The ether was evaporated and the solid residue crystallised from a mixture of petroleum (b. p. 80-100") and acetone (large prisms) or from alcohol (needles). This ester m. p. 88" is readily soluble in acetone benzene or chloroform but sparingly soluble in alcohol carbon tetrachloride, or light petroleum (Pound C = 55-3; H = 4.6. C,H,O,N requires C = 554; H = 4.6%). 3-Nitro-o-toZyl acetate was prepared by treating pure 3-nitro-0-cresol (5 g.) at the ordinary temperature with acetic anhydride (15 c.c.) containing a trace of concentrated sulphuric acid (Smith and Orton Zoc.cit.) until the yellow colour of the nitrocresol had disappeared ; water was added the oily ester extracted with ether, the extract washed with dilute caustic soda and evaporated; the residue crystallised from alcohol in large tablets m. p. 42". This acetate is readily soluble in the ordinary organic solvents and crystallises well from alcohol or petroleum (b. p. 60-80") (Found : 3 5-Dinitro-o-tolyl metate C,H,Me(??O,),*OAc prepared in a similar manner melts a t 96" and crystallises readily from alcohol. It is fairly soluble in alcohol acetone benzene or chloroform but sparingly soluble in petroleum (b.p. 60-80") or carbon tetrachloride (Pound C = 4443; M = 3.4. C,H,O,N requires C = 45.0; C = 55.4 ; H = 4-57:). H = 3.3:/,). The Benxoyl Deri~atives.-5-~Yitro-o-tolyl benzoate, N02*C6H3h~e*OBz , was prepared in the same way as the corresponding acetate (above), a slight excess of pure benzoyl chloride being used in place of acetic anhydride. It melts at 128" is sparingly soluble in ether alcohol or light petroleum and fairly soluble in acetone benzene chloroform or carbon tet,rachloride (Found C = 65-3; H = 4-3. C,,H,,O,N requires C = 65.4; H = 4.28:/,). 3-Nitro-o-tolyl benzoate was obtained by heating anhydrous sodium 3-nitro-o-tolyl oxide (p. 45) with pure benzoyl chloride (2 mols.) for 1 hour at 120". The product was treated in the cold with a mixture of pyridine water and ether ; the ethereal solution was shaken successively with acid and with dilute alkali and finally evaporated ; the residue crystallised from alcohol or petroleum (b.p. SO-80") in needles m. p. 42" b. p. 215-220"/9 mm. Thi GIBSON NITRO-DERIVATIVES OF O-CRESOL. 47 ester is soluble in the usual organic solvents with the exception of petroleum (b. p. S0-8O0) (Pound C = 65.4; I3 = 4.2%). 3 5-~initro-o-fdyl benzoate C,H,Me(NO,),*O~z m. p. 132", prepared in a similar manner from sodium 3 5-djnitro-o-tolyl oxide, crystallises readily from acetone alcohol or benzene ; it is sparingly soluble in alcohol etcher or light petroleum but easily soluble in acetone benzene chloroform or carbon tetrachloride (Found c = 55-7 ; H = 3.4.= 3.3%). The Toluene-p-sulphonyl Derivatives.-5-Nitro-o-tolyl tokuene-p-sulphomte ~030C6H3~~e*O*So~*c7H7 obtained as in the case of the corresponding benzoate (p. Q6) using toluene-p-sulphonyl chloride, crystallises from alcohol petroleum (b. p. 60-80°) or carbon tetrachloride in indefinite plates m. p. 107". It is sparingly soluble in alcohol or light petroleum but fairly soluble in acetone benzene, chloroform or carbon tetrachloride (Pound S = 10-5. C14H130,NS requires S = 10.4:/,). 3-Nitro-o-tolyl toluene-p-sulphonate was prepared by treating sodium 3-nitro-o-tolyl oxide (1 mol.) with pure tolaxene-p-sulphonyl chloride (2 mols.) * the conditions and method of isolation were the same as those described in the case of t h e benzoate (p. 46). The compound melts at 66" and boils at 257"/11 mm.with decom-position but distils unchanged a t 205-.210"/0~5 mm. ; it crystallises well from alcohol in which it is sparingly soluble and dissolves freely in acetone benzene chloroform or carbon tetrachloride (Found S = 10.2%). The corresponding toluene-p-sulphonate from 3 5-dinitro-o-cresol which has already been isolated by Ullmann and San6 (Ber. 1911 44 3730) can be prepared in a similar manner. 3-Nitro-o-chlorotoluene is formed in very small quantities by the action of benzoyl or toluene-p-sulphonyl chloride on sodium 3-nitro-o-tolyl oxide and can be isolat,ed by steam distillation of the crude reaction mixture when a pale yellow pleasant-smelling oil passes over (compare Holleman Bee. trczv. chim. 1908 27 456).I n a similar manner sodium 3 5-dinitro-o-tolyl oxide yields the corresponding 3 5-dinitro-o-chlorotoluene (m. p. 63") which was oxidised to 3 5-dinitro-o-chlorobenzoic acid (m. p. 238"). The Methyl Ethers.-5-Nitro-o-tolyl methyl ether m. p. 64" (Cain and Simonsen J. 1914,105,2390 give m. p. 62") crystallises readily in needles from alcohol or petroleum but is freely soluble in acetone chloroform carbon t'etrachloride or benzene. On ~14Hl,06N requires c = 55.6 ; * The commercial compound was dried in a vacuum at 100' and dissolved in hot petroleum (b. p. 60-80°) the tarry material filtered o f f the solvent removed and the residue distilled under reduced pressure; b. p. 138-139"/9 mm 48 WHITE LIMITS FOR THE PROPAGATION OF F U M E oxidation with boiling dilute permanganate 5-nitro-o-methoxy-benzoic acid (m.p. 150") was obtained in theoretical yield. 3-Nitro-o-tolyl methyl ether was obtained by heating sodium 3-nitro-o-tolyl oxide (I mol.) at 120" with pure methyl sulphate (2 mols.) for 2 hours. The dark-coloured reaction mixture was submitted to distillation in steam the volatile oil extracted with ether and the 3-nitro-o-cresol removed with dilute alkali. The ethereal solution was evaporated the residue distilled under 10 mm. and the product (b. p. 121-122") dissolved in pet'roleum (b. p. 6O-SO0) ; a t - 15" the solution deposited 3-nitro-o-%olyl methyl ether in large needles m. p. 30". The residue from the steam distillation of the methyl ether, treated with calcium carbonate gave a mixture of calcium nitro-cresolsulphonates (p. 43) together with sodium carbonate but the acids could not be separated by the fractional crystallisation of various inorganic and organic sahs which were tried. 3 5-Dinitro-o-tolyl methyl ether (m. p. 72") can be prepared under the conditions just described; the yield is good. 3-Nitro-o-tolyl methyl and ethyl ethers and the corresponding methyl and ethyl derivatives of 3 5-dinitro-o-cresol were also prepared by heat-ing the requisite dry sodium salts with methyl or ethyl toluene-p-sulphonate * in a similar manner. The yields were good and the products had the properties given in the literature. I n conclusion the author desires to express his thanks to the Department of Scientific and Industrial Research for a grant which enabled him to carry out the above work and to Professor F. S. Kipping for his kindly supervision. UNIVERSITY COLLEGE NOTTINGHAM. [Received August 29th 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700042

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

48 WHITE LIMITS FOR THE PROPAGATION OF F U M E VIIL-Limits for the Propagation of Flame in In-flammable Gas-Air Mixtures. Part 11. Mixtures of Nore than One Gas and Air. By ALBERT GREVILLE WHITE. LECHATELIER has put forward a formula connecting the limit for the propagation of flame in a mixture containing two inflammable * Pure toluene-p-sulphonyl chloride (50 g . ; p. 47) was suspended in methyl (or ethyl) alcohol (100 c.c.) well-stirred and 20% caustic soda (10% in excess of 1 mol.) gradually added with cooling; the oil which took the place of the solid was separated with ether and the extract was washed with water, dried with sodium sulphate and evaporated. The residue was crystallised from alcohol at -1P. B. p. of methyl ester 146-14’7O/9 mm.; of ethyl ester 1G5-1GG0/9 xnm IN INBLAJZXABLE GAS-AIR MIXTURES.PART 11. 49 gases and air with the limits for the two inflammable gases taken separately. When generalisecl it bccomes v-hcre n, n z ?z3 . . . are the perccntages of different combustibles found in the final limit mixtxre and .XI N2 iS3 . . . are the per-centages of the same corubust,ibles required to give limit mixtures n-hcm each is niised separately with air. The formula is additive iii charactcr and indicates that if any number of limit mixtures are mixed the resulting mixture will be a limit mixture. It is simple, but uniilicly to be uniiwwdlg true. It has been shown (J. 1922 121 2361) that the formula enables the lower limits of binary mixtures to be calculated fairly accurately from the limits of the purc vapours except for rnixturcs containing carbon clihulphidc where agrevment over a portion of the range was only obtained when an artificial figure was used for the limit of carbon disulphide.At the 11 pper limit of downward propagation the mixtures also followecl Le Chatclier's rule except mixtures containing carbon disulphide but notable discrepancies were sometimes found for other directions of propagation. These could be traced to anomalous bcha,viour of one of the vapours. Thus the formula was clearly inapplicable to a vapoiir giving a cool flame, and by the shzitabla choice of a second vapour the propagation range of ether-second vapour-air was divided into two the mixtures liariiig thus four limits instead of two. Coward Carpenter and Payman (J. 1919 115 27 31) who deal only with propagation upwards conclude that the limits of inflam-inability in air of mixtures of hydrogen carbon monoxide and incthane taken two a t a timc or all -together as well as the limits of coal gas may be calculated by using Le Chatelier's formula.Other workers have drawn the same conclusion but since the nniount of experimental work was small further experiments appeared to be desirable as any radical departure from the formula might throw light on the method of propagation a t the limit of the iildividual gases used. The experimental arrangements were idsnt ical with those used previondy (J. 1934 125,2387) except that the tubes were 5 cm. in diameter unless some other :size is spccitied. The worli was all carried out within the range of 17" So and usmlly between 15" and 19'.The results are given in Tcrcbl2.s 1 and 11. Limits are given as percentages by volume throughout a i d percentagc errors arc calculated as perccntages of the amount of iiifiammablc gas in the limit mixture 50 WHITE LIMITS FOR THE PROPAGATION OF FLAME TABLE I. Showing the ranges of propagation of flame for mixtures of pairs of inflammable gases afid air and the deviatioiis from Le Chatelier's formula. Composition of com- Upward propagation. Downward propagation. by vol. - Deviation a t Deviation at bustihle in mixture % % Range. Lower Upper Range. Lower Upper H,. CH,. Found. Calc. limit. limit. Found. Calc. limit. limit. h /- \ % 0 10 25 50 75 100 s'o H,. 0 25 50 75 100 100 5.40 to 14.25 90 5-50 to -75 4.75 to 18.5 50 4.45 to 26.1 25 4-15 to 38-3 0 4.15 to 74.5 Yo NH,.100 16.1 to 26.6 75 8.65 to 34.5 50 6.10 to 45.2 25 4-75 to 57.0 0 4.15 to 74.5 % C S . % H,. 0 100 4.15 to 74.5 5 95 -to 56.0 10 90 4.00 to -25 75 3.95 to 42.0 30 50 3.70 to 36.5 -5.24 to 5.02 to 17.9 4.69 t o 23.9 4-40 to 36.2 --I 9-36 to 31.7 6.60 to 39.2 5.10 to 51.4 -- -to 70.2 4.02 0 to -3.84 - 3 t o 56.9 3.57 - 4 to 46.0 --- 3 - 8 - 6 --- 8 - 13 - 10 -6-12 to 13.25 6-75 to 16.5 7.35 to 22.3 8.10 to 34.3 9.00 t o 'i4-0 -16-2 t o 30-5 12.5 to 41.0 10.5 to 55.2 9.00 to 74.0 - 9.00 to 74.0 + 25 - 7-95 to -+35 6.85 to 34.0 +26 5-35 to 23.5 6.65 - 1 + 1 to 16.7 to 22.5 8.05 - 1 + 1 to 34.5 7.29 - 1 + 1 - - -"22.1 to *25*5 *20-5 to *28*4 *21.0 to *31*3 I - -7.74 - 3 -to -6.39 - 7 +11 t o 37.8 to 25.4 4.96 - 7 + I N INFLAMMABLE GAS-AIR MIXTURES.PART 11. 51 Composition of com-bustible in mixture. by vol. 0 1 (?*A4. 7 5 100 :; ('2TT,. 0 25 40 50 57 60 65 F -1 3 S5 100 0 1 / O H,. 25 0 0' fT2. 1bO 75 GO 30 43 40 35 95 13 0 Upward propagation. Downward propagation. Range. Found. 3.45 to 33.5 3.13 to 33.3 4-15 to (4.15) 3.55 to (3.50) 3.34 to 3.24 to (3.20) 3-49 to ---to 3-32 t o 3.1 1 to (3.12) 9.93 t o 2.60 'i0 (3.39) -I (2.00) yo CJT,.06 cn,. 0 100 5-40 t o 14-25 25 75 4.75 to 16.1 50 30 4.22 to 19.5 75 25 3.72 to 25.0 100 0 3.13 to 33-3 - Calc. 3.33 to 38.G --3.60 to 3.35 t o 3-19 to 3.10 to -I ---2.99 t o -2.S7 t o 2.76 to ----4-57 to 16.6 3.96 to 20.0 3.50 to 25.0 -% Deviation at - Lower lirnit. 3 --_-+ 2 0 - 2 - 11 -- lo - 8 - 6 __ -- 4 - 6 - 6 -i?ppLr Range. lirnit. Found. 4-15 to 18.0 3.42 to 15.3 0.00 to ti-02 to --4.42 t o -3.40 t o -2.80 t o -6.12 t o 13-25 5-23 to 13.7 4-55 to 14-0 4.05 to 14.8 3.42 to 15.3 -Calc.4.05 t o 19.1 --5-70 to -4.27 to -3-38 t.0 ---5.1 1 to 13-7 4.39 t o 14.2 3.84 to 14.7 -01 /'O Deviation at Lower Upper limit. limit. - 2 f l - 4 -- 1 -The figures in brackets in Table I are lower-limit determinations carried out in tubes 7.5 em. in diameter. Those marked with an asterisk are the values of the propagation range downwards for ammonia-air mixtures as calculated from the ranges found for the various ammonia-hydrogen-air mixtures 52 WELITE LIMITS FOR THE PROPAGATION OF FLAME TABLE 11. Showing the ranges of propagation of flame for mixtures of pairs of inflammable gases and air and the deviations from Le Chatelier's formula.Composition of com- Upward propagation. Downward propagation. bustible ,. - \ -by vol. Deviation a t A ,.--% Deviation a t % % Range. Lower Upper Range. Lower Upper CH,. H,S. Found. Calc. limit. limit. Found. Calc. limit. limit. in mixture % - - - 6.05 - 0 100 4.40 - -t o to 44.5 19.8 10 90 5.15 4.48 -13 - 6.50 6.06 - 7 -to to t o to - - I -- - - - - 7 - 15 85 - -to t o 36.3 33.8 26 75 5.75 4-61 -20 -12 6.90 6.07 -12 - 8 40 60 - - - - 4 50 50 6.03 4.85 -20 -25 7.00 6-08 -13 0 tQ $0 to to 33.0 29.1 19.1 17.6 to t o 17.2 16.5 to to to to 28.8 21.6 15-9 15.9 - 25 - - 60 40 -to t o 26.1 19.6 + 6 - - - 65 35 to to 14.2 15.0 67.5 32.5 - - - - 2 to to 18.6 18.3 78 25 5.80 5.11 -12 + l o 6.75 6.10 -10 + 6 t o to to t o 15-7 17.2 13.6 14.4 100 0 5.40 - - - 6.12 - - -to t o 14.25 13.26 0 100 4.15 to 74.5 10 90 15 85 -to 46.0 25 75 4-27 to 41-3 50 50 4.78 to 40.0 - -to 67.7 to 63.8 4.27 -11 to 55.7 4.21 - 1 - 9.0 to 74.0, to 50.0 4-47 -to 45.5 +54 8-43 t o 38.7 +39 7.85 to 29.0 - + 16 + 15 - -to 58.1 t o 52.5 8.02 - 5 +13 to 43.9 7.24 - 8 + 8 to 31.2 - IN INFLAMMABLE GAS-AIR MIXTURES.PART 11. 53 Composition of com- Upward propagation. bustible ---in mixture bv vol. %-H,S. 75 90 SO0 96 11,s. 0 25 60 *-1 3 90 100 % CZH2. 0 10 25 30 40 50 75 100 % Range. H,. Found. 25 10 0 76 C*HP 100 75 50 25 10 0 % CH,.100 90 75 70 60 50 25 0 5-03 to 40.4 4.72 to 4.40 to 44-5 -2.60 to 8.99 t o 3.44 t o 4.04 t o 4.36 t.0 4.40 to ------5.40 to 14.25 to s5.7 4.40 to 23.4 t o 30.5 to 47.0 3-67 to 47.0 3-07 to 58.0 2.60 to 7 8.0 ---Calc. 4.34 to 49.3 4-37 to ---2.90 t o 3-27 to 3.75 to 4-11 t o -------to 13.5 4.25 to 17.9 to 18.0 to 21.2 3.51 to 24.1 2.99 to 36.8 ---"/s Deviation a t Downward propagation. 7-Ranne. Found, 6.95 t o 23.0 6.05 t o 19.8 2-80 t o 3.23 t o 3-88 to 4.80 to ----6.03 to -6-12 to 13.25 4.85 to 15.7 3.98 t o 20.4 3.27 to 31.2 2.80 to 63.5 " Calc.6.59 to 24.2 --3.23 to 3.83 t o 4-69 to -----4.72 to 16.5 3.84 to 21.9 3.24 t o 32.6 -% Deviation a t Lower limit. - 5 --0 - 1 0 - ---- 3 - 4 - 1 54 WHITE LIMITS FOR THE PROPAGATION OF FLAME Composition of com-bustible in mixture. bv vol. %" % CHI. C,H,,. 0 100 20 80 25 75 50 50 76 25 100 0 Upward propagation. Downward propagation. / I . / - , % Deviation at % Deviation at Range. Found. Calc. 1.43 -to 8.00 - -to to 8-85 8.77 1-75 1.75 to to 2.23 2.26 to to 9.65 10.25 3.15 3.19 to to 11.35 11.92 5.40 -- -to 14.25 Lower Upper Range. Lower Upper limit. limit.Found. Calc. limit. limit. - I - 1.49 -to 4.56 -- - 1 0 - 1.84 1.84 0 f 3 to to 5.30 5.45 + 1 + 6 2.38 2-40 + 1 + 4 to to 6.50 6.78 to to 8-75 8.98 - 6.12 -to 13.25 + 1 + 5 3-47 3-45 - 1 + 3 - - -Discussion of Results. The figures of Table I show that for propagation downwards the deviations from Le Chatelier's rule are not important except for hydrogen-ethylene-air and hydrogen-ammonia-air mixtures. Hydrogen and ethylene appear to hinder one another's burning at the limit as the calculated range is wider than that observed. The results for propagation upwards show that a t both upper and lower limits the presence of hydrogen makes propagation easier than might have been expected when the second inflammable gas is methane or ammonia.This does not apply to mixtures con-taining acetylene or ethylene the discrepancies shown by the upper-limit figures for mixtures of the latter being striking. The cor-responding deviations a t the lower limit are small but when con-sidered in conjunction with the corresponding ones for mixtures containing methane or ammonia they appear to indicate a distinct hindering effect when either ethylene or acetylene is mixed with hydrogen a t the limit. In addition a somewhat curious change of sign occurs for the deviations from Le Chatelier's rule at the lower limit in both methane-hydrogen-air and acetylene-hydrogen-air mixtures. Thus in Fig. 1 which shows the lower-limit figures observed and calculated for the latter mixtures the experimental curve consists of two parts one portion representing mixtures con-taining an excess of hydrogen being slightly below and the other portion distinctly above the curve of calculated values.When the percentage of acetylene in the combmtible gas in the limi IhT IKPLAMNABLE GA4S-41N. MIXTURES. PART 11. 55 mixture is changed from 507; to 57% the limit' rises from 3.24% to 3.49% despite the fact that the limit for acetylene is considerably lowor tha,ii that for hydrogen. Considerable difficulty was experi-enced in determining the limit for the 50% mixture. Mixtures containing an amount of combustible not less thzn 3.24% sometimes propagated flame throughout the length of the tube whilst mixtures containing more than 3-24y0 but less than 3.40% often failed to do so. The difficulty which was also encountered although in a less degree when determining the corresponding limit for the F I G .1. Shozciw i h e loicer limits observed ( f u l l Lin,~) aizd cnlciclcted f r m i Le Chatelic r's rule (dotted l i n e ) fw propagation u p w u ~ r l s iu acet?/l~~ne-hllrlrogc?~-air ~nixtzcra. Percentage of acefyleize ( b y volutne) in the combustible u s d . mixture containing 75yb of methane and 25% of hydrogen iva:; overcome in each case by making numerous trials with each mixture and taking as the linii'c mixture that containing least cornbustiblc in which a flzme was propagated throughout the tube despite thc fact that a mixture containing the same percentage or even n greater percentage of combust Me had failed t o propagate flame ; if one of several similar mixtures propagated flame farther than the others that mixture was aln-ays burning with a fiame more closely resembling that of hydrogen tlian the others.It is thus apparently only when initiated so as to give the hydrogen type of flame that the true limit mixture propagated flame. The analogy with the str,te of things sometimes found when a cool flame can be propagate 56 WHITE LIMITS FOR TEE PROPAGATION OF FLAXE in certain mixtures is at once seen. I n the latter case an ordinary flame goes out during its passage along a limit tube whilst a cool flame always reaches the far end. When a tube 7.5 cm. in diameter was used there was little difficulty in producing the hydrogen type of flame every time in the mixtures referred to above and the limits obtained provided useful confirmation of those obtained in 5 cm.tubes. The values in brackets (7.5 cm. tubes) in Table I. show that the difference between the 5 cm. and the 7.5 cm. results is nowhere important. The agreement for methane-hydrogen-air mixtures was just as good. The observation that €he flame for mixtures shown along part of the curve in Fig. 1 was always of the hydrogen ty-pe whilst that found for those on the other portion more nearly resembled the ordinary lower-limit flame suggests a possible explanation of the results obtained. In Part I it is shown that for upward propagation at the lower limit the hydrogen flame itself and the low calorific value of the limit mixture are quite out of the ordinary. Apparently hydrogen is able to pass on its peculiar properties in part a t any rate to mixtures with other gases but these properties are damped out by excessive amounts of the second gas.With acetylene-hydrogen-air there is between 50% and 570/ of acetylene a limit-that a t which the amount of acetylene becomes sufficient to damp out the peculiar hydrogen flame. This point does not appear to be clearly marked with ethylene-hydrogen-air mixtures but is fairly easily seen for methane-hydrogen-air mixtures although the range of the “ ordinary ” flame here appears to be small. It is unexpected to find that the substitution of 10% of hydrogen for methane causes an increase in the limit from 5.40y0 to 5.50y0. The analogy with the cool flame is well main-tained inasmuch as it takes differing amounts of different gases to suppress the hydrogen flame.That the phenomenon is not con-fined to the mixtures examined is shown by certain results of Coward and his collaborators (Zoc. cit.). They state “ The most striking anomaly was shown by the mixture containing 10 per cent. of hydrogen and 90 per cent. of carbon monoxide where the large difference was in the opposite direction to that normally noted,” but suggest no explanation. The second part of the acetylene-hydrogen-air curve is so distinct from the first as to lead one to attempt to obtain from it some idea as to what the lower limit upwards would be for hydrogen if its own peculiar flame could be suppressed. Assuming Le Chatelier’s rule to hold and making use of the value for 75y0 of acetylene and 25% of hydrogen a figure between 7 and 8% is obtained.This is reasonably near the value for propagation downwards but little reliance can be placed on it for two reasons. In the first plac I N IXFLAMMSBLI; GAS-AIR MIXTURES. PART II. 57 Lc Chatelier's rule is not followed closely by these gases even for propagation downwards and in the second a different and lower value would be obtained by using the figures for methane-hydrogen-air. Nevertheless any figures obtained by extrapolation would be likely to be minimum values so that the figure is certainly suggestive. As ammonia does not propagate flame downwards at the ordinary temperature the ammonia-hydrogen-air values have been utilised to calculate hypothetical values for the ammonia limits. The lower-limit results are reasonably near one another but there is a large increase observable in the upper-limit values as the percentage of hydrogen in the mixture iiicreases.The values obtained appear to point to the fact that for downward propagation a t the upper limit considerable deviations from Le Chatelier's rule take place for these mixtures the experimental values being greater than those calculated. The results given in Table 11 confirm those of Table I in many respects but on the whole the deviations of the experimental values from those calculated appear to be greater. The deviations arc again generally greater for upper-limit results than for lower-limit figures and greater for upwird propagation than €or propagation downw-c"lrds. The work on lower-limit mixtures containing both methane and hydrogen sulphide reveals uiiespect edly large de;-ia-tions from the rule so that these two inflarninable gases appear to hirider one another considerably in propagating flame at the limit.lilethane appears to give much more normal results when used in coiljunction with carbon inonoxide hydrogen certain organic vapours and even n-ith acetylene and ethylene. Accordingly lower-limit mixtures cciitaining hydrogen sulphide and acetylene were tested. Contrary to expectation these results were far nenrcr those calculated the clcviations €or propagation downwards being esccedingly small. Fair deviations were f ouiid €or mixtures coiitainiiig hydrogen sulphide and hydrogen. The upper-limit rcsults are best examined from tile point of view of the ciirves shown in Pigs.2 to 4 which show both experimeiital and calculated values. Tho deviations of Ihc esperiivenial from t he calculated values for me thane-hydrogen sulphide-air mixtures (Fig. 2 ) are sometimes large but the ivost interesting point is the fact that for both directions of propagation the experimental a,nd t hewetical curves cut one mother. For downward propagation, about as much of the experimental curve lies above the theoretical as beIow but this is not the case fcr upward propagation. It s!ic.uld also be noticed that whilst the addition of some methane to 3 hydrogen sulphide-air mixture hinders propagation a t the lower lirlit it scems to promote propagation at the upper limit 68 WECITE LIMITS FOR THE PROPAGATION OF FLAME The values for hydrogen sulphide-hydrogen-air mixtures show fhat for both upper and lower limit mixtures these gases propagate 3ame relatively more easily singly than when both are present in a mixture.Fig. 3 shows that at the upper limit this effect is much more marked for upward than for downward propagation. For mixtures in which more than 80% of the combustible is hydrogen, the limits for both directions of propagation are almost identical, but for mixtures poorer in hydrogen the two curves are quite different. The experimental and the theoretical curves a,re of very FIG. 2. Showing the upper limits obswued (full line) and calculated f r o m Le Chatelier’s II denGtes rule (dotted line) for methane-hydrogen sulphide-air mixtures. downward propagation U propagation upwards.75 100 Percentage of methane in the combustible used. similar form for propagation downwards but for upward propaga-tion the major portion of the experimental curve is nearly horizontal. Experimental difficulty was encountered when the upper limit was being determined for mixtures in which 75% of the inflammable gas was hydrogen and the remainder hydrogen sulphide. The limit figure obtained was dependent on the flame starting up the tube, the type of flame being presumably controlled by the igniting mechanism. It was difficult to control efficiently the type of flame produced and the limit figure was determined as in the case of acetylene-hydrogen-air mixtures (p. 55). The values for the upper limit for methane-acetylene-air mixture IN INFLAMMABLE GAS-AIR MIXTURES.PART 11. 59 FIG. 3. Showing the upper l i m i t s observed ( f u l l line) and calculated from L e Chintelier’s D denotes rule (dotted line) for hydrogen sulphide-hydrogcn-air mixtures. downward propagation U propagation upwards. 25 50 7 5 Percentage of hydrogen sulrphide in the combustible used. FIG. 4. Showing the upper limits obscrucd (full line) trnd ccrlculated f r o m L e Chntelier’s rule (dotted l i n e ) for methan e-ncetylePze-nir mixtures. D denotes downward propagation U propagation upwards. Percentage of methane in combustible uscd 60 WHITE LIMITS FOR THE PROPAGATION OF FLAME ETC. (Fig. 4) are not far from those calculated for downward propagation, the latter being always the greater. For upward propagation the differences between the two sets of results are far greater and are in the opposite direction as the experimental figures are the greater, showing that propagation appears relatively easier when the two gases are present a t the limit than when one is burning alone.The sudden fall in the curve appeared to coincide with a change in the appearance of the flame passing through the mixture. It does not appear difficult to account partly for the left-hand portion of the curve. The high values of acetylene upper limits are largely due to the endothermicity of this compound which can provide much of the heat necessary for the propagation of flame without using up a corresponding amount of oxygen. The reduction of the limit on replacing some acetylene by methane would increase the amount of oxygen in the mixture and this might easily intensify the abnormal effect due to acetylene.A comparison of the present results with those obtained with vapour-air mixtures (Zoc. cit.) is not without interest. Outside mixtures containing carbon disulphide for any two vapours tested, the lower limits and the upper limit for downward propagation for any mixture could be calculated from the limits of the vapours taken singly to an accuracy of about -+ 2%. With the gases now examined an error of five times this amount or even more would often be made under the same conditions. For propagation up-wards both sets of results show that calculation is liable to give results far from those found experimentally. Payman (J. 1923 123 412) suggests that as the rate of reaction in a mixture must depend on the concentration of the reacting gases, speeds of flame in mixtures should be slightly slower than those calculated and a similar divergence should be observable for limit mixtures.He gives figures supporting this view. The effect of mass action should be to reduce the upper limit of a mixture below that calculated. An examination of the eight series of upper-limit results determined in this investigation shows that in the main for downward propagation in four cases the experimental figures are distinctly lower than those calculated whilst in one series they are distinctly higher. For propagation upwards four out of the eight seriesof experimental figures appear to be higher, and four lower than those calculated.Mass action thus appears to be only one and often not the most important one of the factors responsible for divergencies from the calculated values for upper limits in the mixtures examined WALKER SOLUBILITY OF BI-BIVALENT SALTS ETC. 61 Summary. Limits for the propagation of flame have been determined in various mixtures of pairs of combustible gases and air. The results tend to show that in most cases a fair approximation to the value of the limit for a binary mixture can be obtained from the limits for the separate gases by the use of Le Chatelier’s rule. The approximation is generally better for lower than for upper limits, and better for downward propagation than for propagation upwards. The deviations from this rule are considerably greater for the gas mixtures examined than for normal vapour mixtures but no rule can be given for the directiorl of the deviation from the calculatcd values.For gas as for vapour mixtures the type of flame started sometimes determines whet her propag a t ion ’ occurs or no. P wish to thank Messrs. Kobe1 Industries Ltd. and particularly Mr. Rintoul Manager of the Research Section for facilities accorded me for carrying out this work. THE NOBEL LABORATORIES AXDEER. [ Receiued September 9th 1924. 48 WHITE LIMITS FOR THE PROPAGATION OF F U M E VIIL-Limits for the Propagation of Flame in In-flammable Gas-Air Mixtures. Part 11. Mixtures of Nore than One Gas and Air. By ALBERT GREVILLE WHITE. LECHATELIER has put forward a formula connecting the limit for the propagation of flame in a mixture containing two inflammable * Pure toluene-p-sulphonyl chloride (50 g .; p. 47) was suspended in methyl (or ethyl) alcohol (100 c.c.) well-stirred and 20% caustic soda (10% in excess of 1 mol.) gradually added with cooling; the oil which took the place of the solid was separated with ether and the extract was washed with water, dried with sodium sulphate and evaporated. The residue was crystallised from alcohol at -1P. B. p. of methyl ester 146-14’7O/9 mm.; of ethyl ester 1G5-1GG0/9 xnm IN INBLAJZXABLE GAS-AIR MIXTURES. PART 11. 49 gases and air with the limits for the two inflammable gases taken separately. When generalisecl it bccomes v-hcre n, n z ?z3 . . . are the perccntages of different combustibles found in the final limit mixtxre and .XI N2 iS3 .. . are the per-centages of the same corubust,ibles required to give limit mixtures n-hcm each is niised separately with air. The formula is additive iii charactcr and indicates that if any number of limit mixtures are mixed the resulting mixture will be a limit mixture. It is simple, but uniilicly to be uniiwwdlg true. It has been shown (J. 1922 121 2361) that the formula enables the lower limits of binary mixtures to be calculated fairly accurately from the limits of the purc vapours except for rnixturcs containing carbon clihulphidc where agrevment over a portion of the range was only obtained when an artificial figure was used for the limit of carbon disulphide. At the 11 pper limit of downward propagation the mixtures also followecl Le Chatclier's rule except mixtures containing carbon disulphide but notable discrepancies were sometimes found for other directions of propagation.These could be traced to anomalous bcha,viour of one of the vapours. Thus the formula was clearly inapplicable to a vapoiir giving a cool flame, and by the shzitabla choice of a second vapour the propagation range of ether-second vapour-air was divided into two the mixtures liariiig thus four limits instead of two. Coward Carpenter and Payman (J. 1919 115 27 31) who deal only with propagation upwards conclude that the limits of inflam-inability in air of mixtures of hydrogen carbon monoxide and incthane taken two a t a timc or all -together as well as the limits of coal gas may be calculated by using Le Chatelier's formula.Other workers have drawn the same conclusion but since the nniount of experimental work was small further experiments appeared to be desirable as any radical departure from the formula might throw light on the method of propagation a t the limit of the iildividual gases used. The experimental arrangements were idsnt ical with those used previondy (J. 1934 125,2387) except that the tubes were 5 cm. in diameter unless some other :size is spccitied. The worli was all carried out within the range of 17" So and usmlly between 15" and 19'. The results are given in Tcrcbl2.s 1 and 11. Limits are given as percentages by volume throughout a i d percentagc errors arc calculated as perccntages of the amount of iiifiammablc gas in the limit mixture 50 WHITE LIMITS FOR THE PROPAGATION OF FLAME TABLE I.Showing the ranges of propagation of flame for mixtures of pairs of inflammable gases afid air and the deviatioiis from Le Chatelier's formula. Composition of com- Upward propagation. Downward propagation. by vol. - Deviation a t Deviation at bustihle in mixture % % Range. Lower Upper Range. Lower Upper H,. CH,. Found. Calc. limit. limit. Found. Calc. limit. limit. h /- \ % 0 10 25 50 75 100 s'o H,. 0 25 50 75 100 100 5.40 to 14.25 90 5-50 to -75 4.75 to 18.5 50 4.45 to 26.1 25 4-15 to 38-3 0 4.15 to 74.5 Yo NH,. 100 16.1 to 26.6 75 8.65 to 34.5 50 6.10 to 45.2 25 4-75 to 57.0 0 4.15 to 74.5 % C S . % H,. 0 100 4.15 to 74.5 5 95 -to 56.0 10 90 4.00 to -25 75 3.95 to 42.0 30 50 3.70 to 36.5 -5.24 to 5.02 to 17.9 4.69 t o 23.9 4-40 to 36.2 --I 9-36 to 31.7 6.60 to 39.2 5.10 to 51.4 -- -to 70.2 4.02 0 to -3.84 - 3 t o 56.9 3.57 - 4 to 46.0 --- 3 - 8 - 6 --- 8 - 13 - 10 -6-12 to 13.25 6-75 to 16.5 7.35 to 22.3 8.10 to 34.3 9.00 t o 'i4-0 -16-2 t o 30-5 12.5 to 41.0 10.5 to 55.2 9.00 to 74.0 - 9.00 to 74.0 + 25 - 7-95 to -+35 6.85 to 34.0 +26 5-35 to 23.5 6.65 - 1 + 1 to 16.7 to 22.5 8.05 - 1 + 1 to 34.5 7.29 - 1 + 1 - - -"22.1 to *25*5 *20-5 to *28*4 *21.0 to *31*3 I - -7.74 - 3 -to -6.39 - 7 +11 t o 37.8 to 25.4 4.96 - 7 + I N INFLAMMABLE GAS-AIR MIXTURES.PART 11. 51 Composition of com-bustible in mixture. by vol. 0 1 (?*A4. 7 5 100 :; ('2TT,. 0 25 40 50 57 60 65 F -1 3 S5 100 0 1 / O H,. 25 0 0' fT2. 1bO 75 GO 30 43 40 35 95 13 0 Upward propagation. Downward propagation. Range. Found. 3.45 to 33.5 3.13 to 33.3 4-15 to (4.15) 3.55 to (3.50) 3.34 to 3.24 to (3.20) 3-49 to ---to 3-32 t o 3.1 1 to (3.12) 9.93 t o 2.60 'i0 (3.39) -I (2.00) yo CJT,. 06 cn,. 0 100 5-40 t o 14-25 25 75 4.75 to 16.1 50 30 4.22 to 19.5 75 25 3.72 to 25.0 100 0 3.13 to 33-3 - Calc.3.33 to 38.G --3.60 to 3.35 t o 3-19 to 3.10 to -I ---2.99 t o -2.S7 t o 2.76 to ----4-57 to 16.6 3.96 to 20.0 3.50 to 25.0 -% Deviation at - Lower lirnit. 3 --_-+ 2 0 - 2 - 11 -- lo - 8 - 6 __ -- 4 - 6 - 6 -i?ppLr Range. lirnit. Found. 4-15 to 18.0 3.42 to 15.3 0.00 to ti-02 to --4.42 t o -3.40 t o -2.80 t o -6.12 t o 13-25 5-23 to 13.7 4-55 to 14-0 4.05 to 14.8 3.42 to 15.3 -Calc. 4.05 t o 19.1 --5-70 to -4.27 to -3-38 t.0 ---5.1 1 to 13-7 4.39 t o 14.2 3.84 to 14.7 -01 /'O Deviation at Lower Upper limit. limit. - 2 f l - 4 -- 1 -The figures in brackets in Table I are lower-limit determinations carried out in tubes 7.5 em.in diameter. Those marked with an asterisk are the values of the propagation range downwards for ammonia-air mixtures as calculated from the ranges found for the various ammonia-hydrogen-air mixtures 52 WELITE LIMITS FOR THE PROPAGATION OF FLAME TABLE 11. Showing the ranges of propagation of flame for mixtures of pairs of inflammable gases and air and the deviations from Le Chatelier's formula. Composition of com- Upward propagation. Downward propagation. bustible ,. - \ -by vol. Deviation a t A ,.--% Deviation a t % % Range. Lower Upper Range. Lower Upper CH,. H,S. Found. Calc. limit. limit. Found. Calc. limit. limit. in mixture % - - - 6.05 - 0 100 4.40 - -t o to 44.5 19.8 10 90 5.15 4.48 -13 - 6.50 6.06 - 7 -to to t o to - - I -- - - - - 7 - 15 85 - -to t o 36.3 33.8 26 75 5.75 4-61 -20 -12 6.90 6.07 -12 - 8 40 60 - - - - 4 50 50 6.03 4.85 -20 -25 7.00 6-08 -13 0 tQ $0 to to 33.0 29.1 19.1 17.6 to t o 17.2 16.5 to to to to 28.8 21.6 15-9 15.9 - 25 - - 60 40 -to t o 26.1 19.6 + 6 - - - 65 35 to to 14.2 15.0 67.5 32.5 - - - - 2 to to 18.6 18.3 78 25 5.80 5.11 -12 + l o 6.75 6.10 -10 + 6 t o to to t o 15-7 17.2 13.6 14.4 100 0 5.40 - - - 6.12 - - -to t o 14.25 13.26 0 100 4.15 to 74.5 10 90 15 85 -to 46.0 25 75 4-27 to 41-3 50 50 4.78 to 40.0 - -to 67.7 to 63.8 4.27 -11 to 55.7 4.21 - 1 - 9.0 to 74.0, to 50.0 4-47 -to 45.5 +54 8-43 t o 38.7 +39 7.85 to 29.0 - + 16 + 15 - -to 58.1 t o 52.5 8.02 - 5 +13 to 43.9 7.24 - 8 + 8 to 31.2 - IN INFLAMMABLE GAS-AIR MIXTURES.PART 11. 53 Composition of com- Upward propagation. bustible ---in mixture bv vol. %-H,S. 75 90 SO0 96 11,s. 0 25 60 *-1 3 90 100 % CZH2. 0 10 25 30 40 50 75 100 % Range. H,. Found. 25 10 0 76 C*HP 100 75 50 25 10 0 % CH,. 100 90 75 70 60 50 25 0 5-03 to 40.4 4.72 to 4.40 to 44-5 -2.60 to 8.99 t o 3.44 t o 4.04 t o 4.36 t.0 4.40 to ------5.40 to 14.25 to s5.7 4.40 to 23.4 t o 30.5 to 47.0 3-67 to 47.0 3-07 to 58.0 2.60 to 7 8.0 ---Calc.4.34 to 49.3 4-37 to ---2.90 t o 3-27 to 3.75 to 4-11 t o -------to 13.5 4.25 to 17.9 to 18.0 to 21.2 3.51 to 24.1 2.99 to 36.8 ---"/s Deviation a t Downward propagation. 7-Ranne. Found, 6.95 t o 23.0 6.05 t o 19.8 2-80 t o 3.23 t o 3-88 to 4.80 to ----6.03 to -6-12 to 13.25 4.85 to 15.7 3.98 t o 20.4 3.27 to 31.2 2.80 to 63.5 " Calc. 6.59 to 24.2 --3.23 to 3.83 t o 4-69 to -----4.72 to 16.5 3.84 to 21.9 3.24 t o 32.6 -% Deviation a t Lower limit. - 5 --0 - 1 0 - ---- 3 - 4 - 1 54 WHITE LIMITS FOR THE PROPAGATION OF FLAME Composition of com-bustible in mixture.bv vol. %" % CHI. C,H,,. 0 100 20 80 25 75 50 50 76 25 100 0 Upward propagation. Downward propagation. / I . / - , % Deviation at % Deviation at Range. Found. Calc. 1.43 -to 8.00 - -to to 8-85 8.77 1-75 1.75 to to 2.23 2.26 to to 9.65 10.25 3.15 3.19 to to 11.35 11.92 5.40 -- -to 14.25 Lower Upper Range. Lower Upper limit. limit. Found. Calc. limit. limit. - I - 1.49 -to 4.56 -- - 1 0 - 1.84 1.84 0 f 3 to to 5.30 5.45 + 1 + 6 2.38 2-40 + 1 + 4 to to 6.50 6.78 to to 8-75 8.98 - 6.12 -to 13.25 + 1 + 5 3-47 3-45 - 1 + 3 - - -Discussion of Results. The figures of Table I show that for propagation downwards the deviations from Le Chatelier's rule are not important except for hydrogen-ethylene-air and hydrogen-ammonia-air mixtures.Hydrogen and ethylene appear to hinder one another's burning at the limit as the calculated range is wider than that observed. The results for propagation upwards show that a t both upper and lower limits the presence of hydrogen makes propagation easier than might have been expected when the second inflammable gas is methane or ammonia. This does not apply to mixtures con-taining acetylene or ethylene the discrepancies shown by the upper-limit figures for mixtures of the latter being striking. The cor-responding deviations a t the lower limit are small but when con-sidered in conjunction with the corresponding ones for mixtures containing methane or ammonia they appear to indicate a distinct hindering effect when either ethylene or acetylene is mixed with hydrogen a t the limit.In addition a somewhat curious change of sign occurs for the deviations from Le Chatelier's rule at the lower limit in both methane-hydrogen-air and acetylene-hydrogen-air mixtures. Thus in Fig. 1 which shows the lower-limit figures observed and calculated for the latter mixtures the experimental curve consists of two parts one portion representing mixtures con-taining an excess of hydrogen being slightly below and the other portion distinctly above the curve of calculated values. When the percentage of acetylene in the combmtible gas in the limi IhT IKPLAMNABLE GA4S-41N. MIXTURES.PART 11. 55 mixture is changed from 507; to 57% the limit' rises from 3.24% to 3.49% despite the fact that the limit for acetylene is considerably lowor tha,ii that for hydrogen. Considerable difficulty was experi-enced in determining the limit for the 50% mixture. Mixtures containing an amount of combustible not less thzn 3.24% sometimes propagated flame throughout the length of the tube whilst mixtures containing more than 3-24y0 but less than 3.40% often failed to do so. The difficulty which was also encountered although in a less degree when determining the corresponding limit for the F I G . 1. Shozciw i h e loicer limits observed ( f u l l Lin,~) aizd cnlciclcted f r m i Le Chatelic r's rule (dotted l i n e ) fw propagation u p w u ~ r l s iu acet?/l~~ne-hllrlrogc?~-air ~nixtzcra.Percentage of acefyleize ( b y volutne) in the combustible u s d . mixture containing 75yb of methane and 25% of hydrogen iva:; overcome in each case by making numerous trials with each mixture and taking as the linii'c mixture that containing least cornbustiblc in which a flzme was propagated throughout the tube despite thc fact that a mixture containing the same percentage or even n greater percentage of combust Me had failed t o propagate flame ; if one of several similar mixtures propagated flame farther than the others that mixture was aln-ays burning with a fiame more closely resembling that of hydrogen tlian the others. It is thus apparently only when initiated so as to give the hydrogen type of flame that the true limit mixture propagated flame.The analogy with the str,te of things sometimes found when a cool flame can be propagate 56 WHITE LIMITS FOR TEE PROPAGATION OF FLAXE in certain mixtures is at once seen. I n the latter case an ordinary flame goes out during its passage along a limit tube whilst a cool flame always reaches the far end. When a tube 7.5 cm. in diameter was used there was little difficulty in producing the hydrogen type of flame every time in the mixtures referred to above and the limits obtained provided useful confirmation of those obtained in 5 cm. tubes. The values in brackets (7.5 cm. tubes) in Table I. show that the difference between the 5 cm. and the 7.5 cm. results is nowhere important. The agreement for methane-hydrogen-air mixtures was just as good.The observation that €he flame for mixtures shown along part of the curve in Fig. 1 was always of the hydrogen ty-pe whilst that found for those on the other portion more nearly resembled the ordinary lower-limit flame suggests a possible explanation of the results obtained. In Part I it is shown that for upward propagation at the lower limit the hydrogen flame itself and the low calorific value of the limit mixture are quite out of the ordinary. Apparently hydrogen is able to pass on its peculiar properties in part a t any rate to mixtures with other gases but these properties are damped out by excessive amounts of the second gas. With acetylene-hydrogen-air there is between 50% and 570/ of acetylene a limit-that a t which the amount of acetylene becomes sufficient to damp out the peculiar hydrogen flame.This point does not appear to be clearly marked with ethylene-hydrogen-air mixtures but is fairly easily seen for methane-hydrogen-air mixtures although the range of the “ ordinary ” flame here appears to be small. It is unexpected to find that the substitution of 10% of hydrogen for methane causes an increase in the limit from 5.40y0 to 5.50y0. The analogy with the cool flame is well main-tained inasmuch as it takes differing amounts of different gases to suppress the hydrogen flame. That the phenomenon is not con-fined to the mixtures examined is shown by certain results of Coward and his collaborators (Zoc. cit.). They state “ The most striking anomaly was shown by the mixture containing 10 per cent.of hydrogen and 90 per cent. of carbon monoxide where the large difference was in the opposite direction to that normally noted,” but suggest no explanation. The second part of the acetylene-hydrogen-air curve is so distinct from the first as to lead one to attempt to obtain from it some idea as to what the lower limit upwards would be for hydrogen if its own peculiar flame could be suppressed. Assuming Le Chatelier’s rule to hold and making use of the value for 75y0 of acetylene and 25% of hydrogen a figure between 7 and 8% is obtained. This is reasonably near the value for propagation downwards but little reliance can be placed on it for two reasons. In the first plac I N IXFLAMMSBLI; GAS-AIR MIXTURES. PART II. 57 Lc Chatelier's rule is not followed closely by these gases even for propagation downwards and in the second a different and lower value would be obtained by using the figures for methane-hydrogen-air.Nevertheless any figures obtained by extrapolation would be likely to be minimum values so that the figure is certainly suggestive. As ammonia does not propagate flame downwards at the ordinary temperature the ammonia-hydrogen-air values have been utilised to calculate hypothetical values for the ammonia limits. The lower-limit results are reasonably near one another but there is a large increase observable in the upper-limit values as the percentage of hydrogen in the mixture iiicreases. The values obtained appear to point to the fact that for downward propagation a t the upper limit considerable deviations from Le Chatelier's rule take place for these mixtures the experimental values being greater than those calculated.The results given in Table 11 confirm those of Table I in many respects but on the whole the deviations of the experimental values from those calculated appear to be greater. The deviations arc again generally greater for upper-limit results than for lower-limit figures and greater for upwird propagation than €or propagation downw-c"lrds. The work on lower-limit mixtures containing both methane and hydrogen sulphide reveals uiiespect edly large de;-ia-tions from the rule so that these two inflarninable gases appear to hirider one another considerably in propagating flame at the limit. lilethane appears to give much more normal results when used in coiljunction with carbon inonoxide hydrogen certain organic vapours and even n-ith acetylene and ethylene.Accordingly lower-limit mixtures cciitaining hydrogen sulphide and acetylene were tested. Contrary to expectation these results were far nenrcr those calculated the clcviations €or propagation downwards being esccedingly small. Fair deviations were f ouiid €or mixtures coiitainiiig hydrogen sulphide and hydrogen. The upper-limit rcsults are best examined from tile point of view of the ciirves shown in Pigs. 2 to 4 which show both experimeiital and calculated values. Tho deviations of Ihc esperiivenial from t he calculated values for me thane-hydrogen sulphide-air mixtures (Fig. 2 ) are sometimes large but the ivost interesting point is the fact that for both directions of propagation the experimental a,nd t hewetical curves cut one mother.For downward propagation, about as much of the experimental curve lies above the theoretical as beIow but this is not the case fcr upward propagation. It s!ic.uld also be noticed that whilst the addition of some methane to 3 hydrogen sulphide-air mixture hinders propagation a t the lower lirlit it scems to promote propagation at the upper limit 68 WECITE LIMITS FOR THE PROPAGATION OF FLAME The values for hydrogen sulphide-hydrogen-air mixtures show fhat for both upper and lower limit mixtures these gases propagate 3ame relatively more easily singly than when both are present in a mixture. Fig. 3 shows that at the upper limit this effect is much more marked for upward than for downward propagation.For mixtures in which more than 80% of the combustible is hydrogen, the limits for both directions of propagation are almost identical, but for mixtures poorer in hydrogen the two curves are quite different. The experimental and the theoretical curves a,re of very FIG. 2. Showing the upper limits obswued (full line) and calculated f r o m Le Chatelier’s II denGtes rule (dotted line) for methane-hydrogen sulphide-air mixtures. downward propagation U propagation upwards. 75 100 Percentage of methane in the combustible used. similar form for propagation downwards but for upward propaga-tion the major portion of the experimental curve is nearly horizontal. Experimental difficulty was encountered when the upper limit was being determined for mixtures in which 75% of the inflammable gas was hydrogen and the remainder hydrogen sulphide.The limit figure obtained was dependent on the flame starting up the tube, the type of flame being presumably controlled by the igniting mechanism. It was difficult to control efficiently the type of flame produced and the limit figure was determined as in the case of acetylene-hydrogen-air mixtures (p. 55). The values for the upper limit for methane-acetylene-air mixture IN INFLAMMABLE GAS-AIR MIXTURES. PART 11. 59 FIG. 3. Showing the upper l i m i t s observed ( f u l l line) and calculated from L e Chintelier’s D denotes rule (dotted line) for hydrogen sulphide-hydrogcn-air mixtures. downward propagation U propagation upwards. 25 50 7 5 Percentage of hydrogen sulrphide in the combustible used.FIG. 4. Showing the upper limits obscrucd (full line) trnd ccrlculated f r o m L e Chntelier’s rule (dotted l i n e ) for methan e-ncetylePze-nir mixtures. D denotes downward propagation U propagation upwards. Percentage of methane in combustible uscd 60 WHITE LIMITS FOR THE PROPAGATION OF FLAME ETC. (Fig. 4) are not far from those calculated for downward propagation, the latter being always the greater. For upward propagation the differences between the two sets of results are far greater and are in the opposite direction as the experimental figures are the greater, showing that propagation appears relatively easier when the two gases are present a t the limit than when one is burning alone. The sudden fall in the curve appeared to coincide with a change in the appearance of the flame passing through the mixture.It does not appear difficult to account partly for the left-hand portion of the curve. The high values of acetylene upper limits are largely due to the endothermicity of this compound which can provide much of the heat necessary for the propagation of flame without using up a corresponding amount of oxygen. The reduction of the limit on replacing some acetylene by methane would increase the amount of oxygen in the mixture and this might easily intensify the abnormal effect due to acetylene. A comparison of the present results with those obtained with vapour-air mixtures (Zoc. cit.) is not without interest. Outside mixtures containing carbon disulphide for any two vapours tested, the lower limits and the upper limit for downward propagation for any mixture could be calculated from the limits of the vapours taken singly to an accuracy of about -+ 2%. With the gases now examined an error of five times this amount or even more would often be made under the same conditions. For propagation up-wards both sets of results show that calculation is liable to give results far from those found experimentally. Payman (J. 1923 123 412) suggests that as the rate of reaction in a mixture must depend on the concentration of the reacting gases, speeds of flame in mixtures should be slightly slower than those calculated and a similar divergence should be observable for limit mixtures. He gives figures supporting this view. The effect of mass action should be to reduce the upper limit of a mixture below that calculated. An examination of the eight series of upper-limit results determined in this investigation shows that in the main for downward propagation in four cases the experimental figures are distinctly lower than those calculated whilst in one series they are distinctly higher. For propagation upwards four out of the eight seriesof experimental figures appear to be higher, and four lower than those calculated. Mass action thus appears to be only one and often not the most important one of the factors responsible for divergencies from the calculated values for upper limits in the mixtures examined WALKER SOLUBILITY OF BI-BIVALENT SALTS ETC. 61 Summary. Limits for the propagation of flame have been determined in various mixtures of pairs of combustible gases and air. The results tend to show that in most cases a fair approximation to the value of the limit for a binary mixture can be obtained from the limits for the separate gases by the use of Le Chatelier’s rule. The approximation is generally better for lower than for upper limits, and better for downward propagation than for propagation upwards. The deviations from this rule are considerably greater for the gas mixtures examined than for normal vapour mixtures but no rule can be given for the directiorl of the deviation from the calculatcd values. For gas as for vapour mixtures the type of flame started sometimes determines whet her propag a t ion ’ occurs or no. P wish to thank Messrs. Kobe1 Industries Ltd. and particularly Mr. Rintoul Manager of the Research Section for facilities accorded me for carrying out this work. THE NOBEL LABORATORIES AXDEER. [ Receiued September 9th 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700048

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

WALKER SOLUBILITY OF BI-BIVALENT SALTS ETC. 61 IX.-Solubility of Bi-bivalent Salts in Solutions Con-taining CI. Common I o n . By OSWALD J_I>IES JVSLKER. THE investigation of thi solubility of s d t s in dilute solutions of salts with common ions has been confined mainly to the following cases 1. Uni-univalent salt + univalent common ion. 2. Uiii-bivalent salt + univalent coininon ion. 3. Uni-bivalent salt + bivalent common ion. It was shown by Noyes and his co-workers ( J . ,.lmer. C'hem. Xoc., 1911 33 1643 1807) that in cases (1) and (2) the solubility decreases rapidly and the curve obtained by plotting solubility against con-centration of added salt is roughly of the form to be expected from the solubility product principle. I n case (3)) where a salt with a common bivalent ion is added the decrease in solubility is much less than what would be expected from that principle and if the saturating salt is sufficiently soluble the common ion may actually bring about an increase in the solubility.Fewer cases have been studied in which the saturating salt is bi-bivalent and such cases as have been examined ( e . g . Harkins and Paine J.Bmer. C'hem. SOC., 1919 41 1162) havc shown that here also the solubility decrease brought about by the common ion is less than what would be expected. More recently there has been a tendency to rejec 62 WALKER SOLUBILITY OF BI-BIVALENT SALTS the conductivity method of calculating ionic concentrations which was the method used in applying the solubility product principle, and the question of solubility effects has been approached from a different point of view based on thermodynamic considerations which involve the principles of the inter-ionic attraction theory.With a view to get further evidence concerning the solubility effects in the system bi-bivalent salt + bivalent common ion, the solubilities of several salts have been investigated. For this purpose the succinates and malonates of the alkaline-earth metals afford a suitable range of concentrations. The solubilities of the various salts considered expressed in gram-molecules per 1000 grams of water varied between 0.016 and 0.082 weight molar, whilst the total salt concentration did not exceed 0-1 weight molar, except in the case of calcium succinate as saturating salt with which a maximum of about 0.3 weight molar was reached.E x P E R I M E N T A L . The saturating salts were prepared from pure reagents by pre-cipitation thorough washing and drying a t the temperature requisite to give the anhydrous salt. Sodium and magnesium succinates were obtained by crystallisation from neutralised succinic acid solutions and were recrystallised several times. Analysis confirmed the purity of the salts thus obtained. The solubility determinations were carried out in 100 C.C. Jena conical flasks closed with rubber stoppers and provided with rubber caps. Excess of the saturating salt and a weighed quantity of the other salt were added to a known weight of water in the flask, and the mixture was rotated in a thermostat kept a t 25" 5 0.1" until equilibrium had been reached (about 30 hours).The solution, after standing in the thermostat for an hour was filtered upward by suction through a small filter paper into a weighed flask which was also in the thermostat. After weighing the solution was carefully washed out into a beaker and the solubility was obtained by determining gravimetrically the amount of the metallic radical of the saturating salt. Barium was estimated in most cases as sulphate but in presence of calcium Browning's method (Amer. J . Sci. 1892 [iii] 43 314) depending on the difference in solubility of the nitrates in amyl alcohol was employed. Calcium was pre-cipitated as oxalate and weighed as sulphate the precipitation in presence of magnesium being carried out twice. Strontium was precipitated as carbonate and weighed as sulphate.In the case of strontium malonate + strontium chloride the chloride in the solution was determined gravimetrically as silver chloride and the amount of strontium as malonate was determined by subtraction o I N SOLUTIONS CONTAINING A COMMON ION. 63 the strontium present as chloride from the total stront'ium. Inde-pendent solubility determinations gave results agreeing within 0.5% -The results are shown in Table I s being the solubility expressed in gram-molecules per 1000 grams of water corresponding to the weight-molar concentration c of added salt; so is the solubility 'rABLE I. S. C. S. c . Ba succ. + Na succ. 0.01307 0.00795 0.02523 0.01828 0.01154 0.01575 0.02349 0.03103 0.00987 0.03149 0*0301'3 0.06149 0.00913 0.04726 Sr mal.+ SrC1,. so -= 0.01570. so = c).03050. S . C. Ba succ. + Mg succ. so = 0.01570. 0.01307 0.00770 0.01294 0-01538 0.01 155 0.03074 0.01063 0*04620, 0.01024 0.06149 Sr succ. + Na succ. Ca succ. +- Na succ. Ea succ. f Ca SIICC. s, = 0.02013. so = 0.05252. so = 0.01570. 0.01740 0.00938 0.08013 0.00826 0.01383 0.00798 0.01535 0.01875 0.07103 0.05OG 0.01273 0.01597 0.01322 0.03751 0-0G-l-95 0.1014 0.01153 0.03193 0.01231 0.05382 0-061:38 0.1526 0.01143 0.07457 0.05759 0.2560 Calcium succinete + Magnesium succinate. so = 0.08252. s ............... 0.07769 0.07474 0.07340 0.07173 0.07087 c ............... 0.04121 0.06179 0.08230 0-1231 0-1631 of the saturating salt in pure water. The Solubility effects however, can be more easily compared by means of the ratios s/so and c/s0, which express respectively the concentrations of the saturating salt and of the added salt in terms of the solubility of the former in pure water.These ratios correspond to the terms " fractional solubility " and " fractional ooncentraticn " employed by Harkins ( J . Arner. Chem. SOC. 1911 33 1851). I n Figs. 1 and 2 the values of s/s are plotted against the values cf c/s0 for the additicn respec-tively of uni- bivalent and hi-bivalent salt. For comparison a typical curve for the system uni-univalent salt + univalent common ion (silver propionate 4- sodium propionate Arrhenius 2. phylsikal. Ghem. 1899 31 225) is also shown (dotted curve). The curves all lie considerably above the curve for the uni-univalent salt and for any one saturating salt the curve of Fig.2 lies above that of Fig. 1 . Moreover for one type of added salt, the curves all lie in the order of the solubility of the saturating salt in pure water the curve taking a higher position the greater the solubility; this order was found to hold by Harkins (loc. cit.) for. the salts investigated by him. The lowering effects of calcium and magnesium succinstes on thc solubility of barium succinate are almost equal the cremes on cur\-e 2 (Fig. 2 ) denoting additicii of calcium succinate 64 WALKER SOLUBILITY OF BI-BIVALENT SALTS Noyes ( J . Amer. Chem. Xoc. 1924 46 1080 1098) in his critical presentation of the interionic attraction theory of ionised solutes as put forward by Milner (Phil. Mag.1912 [vi] 23 551 ; 1913 25, 742) and by Debye and Hiickel (PhysikaE. Z. 1923 24 185) uses some of the existing data on the solubility of salts in salt solutions in order to test the validity of the theory. He finds that the solu-bility effects should be given by an equation which takes the follow-1.0 0.8 -5 0.6 04 0.2 FIG. 1. --_ -_ I CaSucc + N~,,SUCC 2 SrMd+SrCI, 3 Sr S~cc+N~~,Succ. 4 BaSucc+Na,Succ. I 1.0 2.0 3.0 6 4%. FIG. 2. I 1 i - '''\.\\\-)I +CaSutc.+ I Ci6ucc+Mgbcr. 2 BaSucc+MgSucc. Q 1 1.0 2.0 3.9 4.0 C/So. ing form for bi-bivalent saturating salts so s and c being the con-centration terms hitherto employed in this paper, where cc has the theoretical value of 0.357 for dilute solutions a t 25". CC'V~ denotes the summation of ion concentration (c') x square of valence of ion ( ~ 2 ) for all the ions present half this quantity representing the " ionic strength " as defined by Lewis and Randall ( J .Arner. Chem. Soc. 1921 43 1140). In Table I1 are shown the values of the coefficient for the two least soluble salts barium succinate and strontium succinate calculated from the solubility data in Table I. The values for the system calcium sulphate + magnesium sulphate calculated from the data quoted in Noyes's paper are also shown. The values in each column are arranged in order of increasing total salt concentration and it will be seen that in this order cc in most cases decreases reaching a value of about 0.15 at ionic strengths between 0.2 and 0.45 molar. The data for the case of calcium succinate as saturating salt a salt about four times as soluble as any of the saturating salts in Table 11 give even smaller values of a about 0.09 in the most concentrated solutions.Whils I N SOLUTIONS CONTAINING A COMMON ION. tj 5 “ Ionic strength. 0.08 to 0.20 0.20 to 0.45 3 2 C ’ Y Z . Ba succ. + ” Mg succ. s,=O.O1570. ( 0.181 0.177 0-153 0.147 TABLE I1 Values of a . Ba succ. + Brz suec. -1- Sr succ. + Ca succ. Na succ. Na succ. ~,=0*01570. so=0.c)lS7@. ~ ~ - 0 * 0 2 0 1 3 . 0.173 0.105 0.1% 0.172 0.171 0.166 0.164 0.16s 0-158 0.1G5 0-152 0.145 CnS04 + 31gso4. S = 0.015 17. 0.201 0.19G 0.181 0.169 0.150 the values of cc in the first three rows of the table are constant to within about loyo they are still somewhat smaller thzn the value 0.238 which Noyes finds to satisfy the experimental facts up to ionic strengths of 0.1,12’ in the case of the three salts of higher valence type quoted by him.The differences in the values of u from one another are greater than those which could be due to experimental error in the value of the solubility. An error in the latter as great as I:( (the actual maximum error was about 0.5:;) makes a differ-ence of about 596 in the values of a. Although u increases with decreasing salt concentration extra-polation from the graph obtained by plotting conceiiiration against the corresponding values of ct does not show any tendency for 2 to reach a value as high as 0.357 even a t very small concentrations. In order therefore to obtain data a t much smaller eoncentrations than those employed so far in this paper some experiments were carried out on the solubility of barium and magnesium osalates in presence of barium chloride and magnesium sulphate respectively.It was hoped that the results of these experiments would give an indication of the value of the “ constnnt ” O( in Noyes’s equation a t these much smaller concentrations (about 0.003 to 0.0006 weight-molar) for which the equation ought to hold more closely than in the cases dready dealt with. The solubiiity was determined in each case by titration of the aniount of oxalate present in about 200 g. of solution with carefully standardised permanganate solution of such a strength that from 30-60 C.C. were used up in t he titration.From these results no ccnsistent \-clue for u was obtained in thc case of barium oxalate. At small concentrations corresponding to the solubility of barium oxalate a small error in the experiment-ally obtained value of the solubility becomes highly magnified in t lie cnlculat8ion of a which may consequently vary enormously. With the more soluble magnesium salt the influence of an experi-mental error is not so marked an error of 1-07; in the solubility causing an error of about 57; in the value of U. The results obtained with rnagr,esium oxalate (.co = 0.00307) in presence of magnesium VOL. (‘XXVII. 66 AESOHLIMANN LEES MCCLELAND AND N I C m : sulphate are as follow the values of oc being calculated from Noyes's equation : 8. C. a. 0,00235 0.00272 0.285 0*00215 0.00491 0.320 These values of u are much nearer the theoretical value of 0.357, and the agreement between the two values is fairly good as the experimental error here corresponded with an error of about 5% in the value of u.Xummary . (1) The solubility has been determined at 25" of some bi-bivalent salts vix. succinates and malonates of calcium strontium and barium in pure water and in solutions containing varying concen-trations of a common ion. Curves are given which show that the solubility is in every case greater than would be predicted by the solubility product rule and that the divergence is more marked the greater the solubility of the salt considered and greater for an added bi-bivalent salt than for an added uni-bivalent salt.(2) The solubility data have been examined from the point of view of the interionic attraction theory of ionised solutes as developed by Debye and Hiickel and especially from the solubility point of view by Noyes. The results obtained in this paper are in good qualitative agreement with this theory and in the case of the very sparingly soluble magnesium oxalate a fair quantitative agreement is obtained. In conclusion I wish to thank Professor Sir James Walker CHEMISTRY DEPARTMENT, for the interest taken in the progress of this work. EDINBURGH UNIVERSITY. [Received September 26th 1924. WALKER SOLUBILITY OF BI-BIVALENT SALTS ETC. 61 IX.-Solubility of Bi-bivalent Salts in Solutions Con-taining CI. Common I o n . By OSWALD J_I>IES JVSLKER. THE investigation of thi solubility of s d t s in dilute solutions of salts with common ions has been confined mainly to the following cases 1.Uni-univalent salt + univalent common ion. 2. Uiii-bivalent salt + univalent coininon ion. 3. Uni-bivalent salt + bivalent common ion. It was shown by Noyes and his co-workers ( J . ,.lmer. C'hem. Xoc., 1911 33 1643 1807) that in cases (1) and (2) the solubility decreases rapidly and the curve obtained by plotting solubility against con-centration of added salt is roughly of the form to be expected from the solubility product principle. I n case (3)) where a salt with a common bivalent ion is added the decrease in solubility is much less than what would be expected from that principle and if the saturating salt is sufficiently soluble the common ion may actually bring about an increase in the solubility.Fewer cases have been studied in which the saturating salt is bi-bivalent and such cases as have been examined ( e . g . Harkins and Paine J.Bmer. C'hem. SOC., 1919 41 1162) havc shown that here also the solubility decrease brought about by the common ion is less than what would be expected. More recently there has been a tendency to rejec 62 WALKER SOLUBILITY OF BI-BIVALENT SALTS the conductivity method of calculating ionic concentrations which was the method used in applying the solubility product principle, and the question of solubility effects has been approached from a different point of view based on thermodynamic considerations which involve the principles of the inter-ionic attraction theory.With a view to get further evidence concerning the solubility effects in the system bi-bivalent salt + bivalent common ion, the solubilities of several salts have been investigated. For this purpose the succinates and malonates of the alkaline-earth metals afford a suitable range of concentrations. The solubilities of the various salts considered expressed in gram-molecules per 1000 grams of water varied between 0.016 and 0.082 weight molar, whilst the total salt concentration did not exceed 0-1 weight molar, except in the case of calcium succinate as saturating salt with which a maximum of about 0.3 weight molar was reached. E x P E R I M E N T A L . The saturating salts were prepared from pure reagents by pre-cipitation thorough washing and drying a t the temperature requisite to give the anhydrous salt.Sodium and magnesium succinates were obtained by crystallisation from neutralised succinic acid solutions and were recrystallised several times. Analysis confirmed the purity of the salts thus obtained. The solubility determinations were carried out in 100 C.C. Jena conical flasks closed with rubber stoppers and provided with rubber caps. Excess of the saturating salt and a weighed quantity of the other salt were added to a known weight of water in the flask, and the mixture was rotated in a thermostat kept a t 25" 5 0.1" until equilibrium had been reached (about 30 hours). The solution, after standing in the thermostat for an hour was filtered upward by suction through a small filter paper into a weighed flask which was also in the thermostat.After weighing the solution was carefully washed out into a beaker and the solubility was obtained by determining gravimetrically the amount of the metallic radical of the saturating salt. Barium was estimated in most cases as sulphate but in presence of calcium Browning's method (Amer. J . Sci. 1892 [iii] 43 314) depending on the difference in solubility of the nitrates in amyl alcohol was employed. Calcium was pre-cipitated as oxalate and weighed as sulphate the precipitation in presence of magnesium being carried out twice. Strontium was precipitated as carbonate and weighed as sulphate. In the case of strontium malonate + strontium chloride the chloride in the solution was determined gravimetrically as silver chloride and the amount of strontium as malonate was determined by subtraction o I N SOLUTIONS CONTAINING A COMMON ION.63 the strontium present as chloride from the total stront'ium. Inde-pendent solubility determinations gave results agreeing within 0.5% -The results are shown in Table I s being the solubility expressed in gram-molecules per 1000 grams of water corresponding to the weight-molar concentration c of added salt; so is the solubility 'rABLE I. S. C. S. c . Ba succ. + Na succ. 0.01307 0.00795 0.02523 0.01828 0.01154 0.01575 0.02349 0.03103 0.00987 0.03149 0*0301'3 0.06149 0.00913 0.04726 Sr mal. + SrC1,. so -= 0.01570. so = c).03050. S . C. Ba succ. + Mg succ. so = 0.01570. 0.01307 0.00770 0.01294 0-01538 0.01 155 0.03074 0.01063 0*04620, 0.01024 0.06149 Sr succ.+ Na succ. Ca succ. +- Na succ. Ea succ. f Ca SIICC. s, = 0.02013. so = 0.05252. so = 0.01570. 0.01740 0.00938 0.08013 0.00826 0.01383 0.00798 0.01535 0.01875 0.07103 0.05OG 0.01273 0.01597 0.01322 0.03751 0-0G-l-95 0.1014 0.01153 0.03193 0.01231 0.05382 0-061:38 0.1526 0.01143 0.07457 0.05759 0.2560 Calcium succinete + Magnesium succinate. so = 0.08252. s ............... 0.07769 0.07474 0.07340 0.07173 0.07087 c ............... 0.04121 0.06179 0.08230 0-1231 0-1631 of the saturating salt in pure water. The Solubility effects however, can be more easily compared by means of the ratios s/so and c/s0, which express respectively the concentrations of the saturating salt and of the added salt in terms of the solubility of the former in pure water.These ratios correspond to the terms " fractional solubility " and " fractional ooncentraticn " employed by Harkins ( J . Arner. Chem. SOC. 1911 33 1851). I n Figs. 1 and 2 the values of s/s are plotted against the values cf c/s0 for the additicn respec-tively of uni- bivalent and hi-bivalent salt. For comparison a typical curve for the system uni-univalent salt + univalent common ion (silver propionate 4- sodium propionate Arrhenius 2. phylsikal. Ghem. 1899 31 225) is also shown (dotted curve). The curves all lie considerably above the curve for the uni-univalent salt and for any one saturating salt the curve of Fig. 2 lies above that of Fig. 1 . Moreover for one type of added salt, the curves all lie in the order of the solubility of the saturating salt in pure water the curve taking a higher position the greater the solubility; this order was found to hold by Harkins (loc.cit.) for. the salts investigated by him. The lowering effects of calcium and magnesium succinstes on thc solubility of barium succinate are almost equal the cremes on cur\-e 2 (Fig. 2 ) denoting additicii of calcium succinate 64 WALKER SOLUBILITY OF BI-BIVALENT SALTS Noyes ( J . Amer. Chem. Xoc. 1924 46 1080 1098) in his critical presentation of the interionic attraction theory of ionised solutes as put forward by Milner (Phil. Mag. 1912 [vi] 23 551 ; 1913 25, 742) and by Debye and Hiickel (PhysikaE. Z. 1923 24 185) uses some of the existing data on the solubility of salts in salt solutions in order to test the validity of the theory.He finds that the solu-bility effects should be given by an equation which takes the follow-1.0 0.8 -5 0.6 04 0.2 FIG. 1. --_ -_ I CaSucc + N~,,SUCC 2 SrMd+SrCI, 3 Sr S~cc+N~~,Succ. 4 BaSucc+Na,Succ. I 1.0 2.0 3.0 6 4%. FIG. 2. I 1 i - '''\.\\\-)I +CaSutc.+ I Ci6ucc+Mgbcr. 2 BaSucc+MgSucc. Q 1 1.0 2.0 3.9 4.0 C/So. ing form for bi-bivalent saturating salts so s and c being the con-centration terms hitherto employed in this paper, where cc has the theoretical value of 0.357 for dilute solutions a t 25". CC'V~ denotes the summation of ion concentration (c') x square of valence of ion ( ~ 2 ) for all the ions present half this quantity representing the " ionic strength " as defined by Lewis and Randall ( J .Arner. Chem. Soc. 1921 43 1140). In Table I1 are shown the values of the coefficient for the two least soluble salts barium succinate and strontium succinate calculated from the solubility data in Table I. The values for the system calcium sulphate + magnesium sulphate calculated from the data quoted in Noyes's paper are also shown. The values in each column are arranged in order of increasing total salt concentration and it will be seen that in this order cc in most cases decreases reaching a value of about 0.15 at ionic strengths between 0.2 and 0.45 molar. The data for the case of calcium succinate as saturating salt a salt about four times as soluble as any of the saturating salts in Table 11 give even smaller values of a about 0.09 in the most concentrated solutions.Whils I N SOLUTIONS CONTAINING A COMMON ION. tj 5 “ Ionic strength. 0.08 to 0.20 0.20 to 0.45 3 2 C ’ Y Z . Ba succ. + ” Mg succ. s,=O.O1570. ( 0.181 0.177 0-153 0.147 TABLE I1 Values of a . Ba succ. + Brz suec. -1- Sr succ. + Ca succ. Na succ. Na succ. ~,=0*01570. so=0.c)lS7@. ~ ~ - 0 * 0 2 0 1 3 . 0.173 0.105 0.1% 0.172 0.171 0.166 0.164 0.16s 0-158 0.1G5 0-152 0.145 CnS04 + 31gso4. S = 0.015 17. 0.201 0.19G 0.181 0.169 0.150 the values of cc in the first three rows of the table are constant to within about loyo they are still somewhat smaller thzn the value 0.238 which Noyes finds to satisfy the experimental facts up to ionic strengths of 0.1,12’ in the case of the three salts of higher valence type quoted by him.The differences in the values of u from one another are greater than those which could be due to experimental error in the value of the solubility. An error in the latter as great as I:( (the actual maximum error was about 0.5:;) makes a differ-ence of about 596 in the values of a. Although u increases with decreasing salt concentration extra-polation from the graph obtained by plotting conceiiiration against the corresponding values of ct does not show any tendency for 2 to reach a value as high as 0.357 even a t very small concentrations. In order therefore to obtain data a t much smaller eoncentrations than those employed so far in this paper some experiments were carried out on the solubility of barium and magnesium osalates in presence of barium chloride and magnesium sulphate respectively.It was hoped that the results of these experiments would give an indication of the value of the “ constnnt ” O( in Noyes’s equation a t these much smaller concentrations (about 0.003 to 0.0006 weight-molar) for which the equation ought to hold more closely than in the cases dready dealt with. The solubiiity was determined in each case by titration of the aniount of oxalate present in about 200 g. of solution with carefully standardised permanganate solution of such a strength that from 30-60 C.C. were used up in t he titration. From these results no ccnsistent \-clue for u was obtained in thc case of barium oxalate. At small concentrations corresponding to the solubility of barium oxalate a small error in the experiment-ally obtained value of the solubility becomes highly magnified in t lie cnlculat8ion of a which may consequently vary enormously.With the more soluble magnesium salt the influence of an experi-mental error is not so marked an error of 1-07; in the solubility causing an error of about 57; in the value of U. The results obtained with rnagr,esium oxalate (.co = 0.00307) in presence of magnesium VOL. (‘XXVII. 66 AESOHLIMANN LEES MCCLELAND AND N I C m : sulphate are as follow the values of oc being calculated from Noyes's equation : 8. C. a. 0,00235 0.00272 0.285 0*00215 0.00491 0.320 These values of u are much nearer the theoretical value of 0.357, and the agreement between the two values is fairly good as the experimental error here corresponded with an error of about 5% in the value of u. Xummary . (1) The solubility has been determined at 25" of some bi-bivalent salts vix. succinates and malonates of calcium strontium and barium in pure water and in solutions containing varying concen-trations of a common ion. Curves are given which show that the solubility is in every case greater than would be predicted by the solubility product rule and that the divergence is more marked the greater the solubility of the salt considered and greater for an added bi-bivalent salt than for an added uni-bivalent salt. (2) The solubility data have been examined from the point of view of the interionic attraction theory of ionised solutes as developed by Debye and Hiickel and especially from the solubility point of view by Noyes. The results obtained in this paper are in good qualitative agreement with this theory and in the case of the very sparingly soluble magnesium oxalate a fair quantitative agreement is obtained. In conclusion I wish to thank Professor Sir James Walker CHEMISTRY DEPARTMENT, for the interest taken in the progress of this work. EDINBURGH UNIVERSITY. [Received September 26th 1924.

ISSN:0368-1645    

DOI:10.1039/CT9252700061

出版商:RSC    

年代:1925

数据来源: RSC