摘要:

J O U R N A L OF THE CHEMICAL SOCIETY. TRANSACTIONS. A. CHASTON CHAPMAN. A. W. CROSSLEY C.M.G.,D.Sc.,F. R.S. SIR JAMES J. DOBBIE MA. D.Sc., M. 0. FOIISTER n.Sc. Ph.D. F.R.S. T. A. HENRY D.Sc. J. T. HEWITT M.A. D.Sc. PIi.D., F. R.S. F.R.S. C. A. KEANE D.Sc. Ph.D. T. M. LGWRY O.B.E. D.Sc. F.R.S. G. T. MORGAN D.Sc. F.R.S. J. C. PHILIP O.B.E. D.Sc. Ph.D. A. SCOTT M.A. D.Sc. F.R.S. S. SMILES 0. B.E. D.Sc. F. R.S. J. F. THOILPE C.B.E. D.Sc. Ph.D., F. R.. S. $bitor : J. C. GAIN D.Sc. 58 I1 b- Mt ax : A. J. GILEENAWAY. 2Jrjaiattrnt sub-Qbitar : CLARENCE SMITH D.Sc. 1919. VOl. cxv. LONDON: GURNEY & JACKSON 33 PATERNOSTER ROW E.C. 4. 19 19 PRINTED IN GREAT BRITAIN BY REWARD CLAY & SONS LIMITED, BRUNSWICK ST. STAMFORD RT. S.E. L AND BUNGAY.SUFFOLK J O U R N A L OF THE CHEMICAL SOCIETY. TRANSACTIONS. A. CHASTON CHAPMAN. A. W. CROSSLBY C.M.G. D.Sc.,F.R.S. SIR JAMES J. DOBBIE M.A. D.Sc., M. 0. FORSTER D.Sc. Ph.D. F.R.S. T. A. HENRY D.Sc. J. T. HEWITT M.A. D.Sc. Ph.D., P.R.S. F.R. S. C. A. KEANE D.Sc. Ph.D. T. M. LOWRY O.B.E.,D.Sc. F.R.S. G. T. MORGAN D.Sc. F.R.S. J. C. PBILIP O.B.E. D.Sc. Ph.D. A. SCOTT M.A. D.Sc. F.R.S. S. SMILES O.B.E. D.Sc. F.R.S. J. F. THORPE C.B.E. D.Sc. Ph.D., F. R. S. @bitox : J. C. CAIN D.Sc. Snb-Qbitm : A. J. GREENAWAY. $j*ssij*strrtrt Snb- fibitax : CLARENCE SMITH D. Sc. 1919 Vol. CXV. Put I. pp. 1-712. LONDON: GURNEY dz JACESON 33 PATERNOSTER ROW E.C. 4. 1919 PRINTED IN QRRAT BRITAIN RY RICHARD CLAY & SONS LIMITED, RRUNSfICK ST.STAMFORD ST. S.E. 1, AND BUNOAY BUFFOLK CONTENTS. PAPERS CO.MMQNICATED TO THE CHEMICAL SOCIETY. PAGE THE Conception of the Chemical Elemeut as Enlarged by the Study of Radioactive Change. A Lecture delivered before the Chemical Society on December 19 th 19 18. By FREDERICK SODDY . . . I 1.-The Dilution Limite of Inflfimmability of Gasecjus Mixtnreg. Part 111. The Lower Limits of some Mixed Inflammable Gases with Air. Part IV. The Upper Limits of some Gases Singly and Mixed in Air. BY HUBERT FRANK COWARD CHARLES WILLIAM CARPENTER and WILLIAM PATMAN . . 27 11.-The Propagation of Flame through Tulm of Small Dia-meter. Part 11. By WrLLIAbf PAYMAN and RICHARD VERPI'ON WHEELER . . 36 111.-Mixtures of Nitrogen Peroxide and Nitric Acid.By WILLIAM ROBERT BOUSFIELD K.C. . . 45 1V.-The Effect of Dilution in Electro-titrimetric Analyses. By GILBERT ARTHUR FREAK . . 55 V.-The Optically Active Neomethylhydrindamines. By (the late) LT. JOSEPH WALTEB HARRIS . . 61 V1.-Chromatocobaltirmmines By SAMUEL HENRY CLIFFORD BRIGGS . . 67 VI1.-Glyceryl Methyl Ether Dinitrate (a-Methylin Dinitrate). By DAVID TREVOR JONES . . 76 VII1.-The Inflammation of Mixtures of Ethane and Air in tl Closed Vessel The Effects of Turbulence. By RICHARD VERHON WHEELER . . . . 81 1X.-The Ignition of Explosive Gases by Electric Sparks. By JOEN DAVID &RGAN . . 94 X.-The Physicd Constants of Nicotine. Part I. Specific Rotatory Power of Nicotine in Aqueous Solution. By HARRY JEPHCOTT . 104 XI.-The Sub-acetate and Sub-sulphate of Lead.By HENRY GEORGE DENHAM . . 109 XI[.-The Synthesifi of Ammonia at High Temperatures. Part 111. By EDWARD BRADFORD MAXTED . 113 XIIT.-The Effect of some Simple Electrolytes on the Tempera-ture of Maximum Density of Water. By ROBERT WRIGHT 119 X1V.-Polar and Non-polar Valency. By RAJENDRALAL 1h . 127 XV.-The Interaction of Stannous and Arsenious Chlorides. By I~EUINALD GRAEAM DURRANT . . 13 i V CONTENTS. XV1.-Experiments on the Elimination of the Carbethoxyl Group from the Tautomeric Systems. Part I. Derivatives of Indene. By CHRISTOPHER KELK INGOLD and JOCELYN FIELD THORPE . . 143 XVI1.-The Preparation of Monomethylamine from Chloro-picrin. By PERCY FARADAY ERANKLAXD FREDERICK CHALLENGER and NOEL ALBERT NICHOLLS . . 159 XVII1.-The Alkaloids of Holarrhena congolensis Stspf.By FRANK LEE PYMAN . . . . 163 X1X.-Meta-substituted Aromatic Selenium Compounds. By FRANK LEE PYMAN . . 166 XX.-The rt-Butylarylamines. Part 111. Constitution of the Nitro-derivatives of n- Butyl-p-toluidine. By JOSEPH REILLY and WILFRED JOHN HICKINBOTTOM . . 175 XXL-Studies in Catalysis. Part X. The Applicability of the Radiation Hypothesis t o Heterogeneous Reactions. By WILLIAM CUDMORE MCCULLAGE LEWIS . . 182 XX1I.-The Estimation of the Methoxyl Group. By JOHN THEODORE HEWITT and WILLIAX JACOB JONES . 193 XXII1.-The Preparation of Monomethylaniline. By PERCY FARADAY FRANKLAND FREDERICK CHALLENGER and NOEL ALBERT NICROLLS . . 198 XX1V.-Equilibria in the Reduction of Oxides by Carbon. By ROLAND EDGAR SLAUE and GEOFFREY ISHEEWOOD HIGSON .205 XXV.-The Dissociation Pressures of some Nitrides. By ROLAND EDGAR SLADE and GEOFFREY ISHERWOOD HIGSON . 215 XXV1.-Nitro- Ary1:tzo- and Amino-glyoxalines. By ROBERT GEORGE FARGHER and FRANK LEE YYMAN . . . 217 XXVT.1.-Mercury Mercaptide Nitrites and their Reaction with the Alkyl Iodide. Part IV. Chain Compounds of Sulphur (cqntinued). By PRAFULLA CHANDRA RAY and PRAFULLA CHANDRA GUHA . . 261 XXVII1.-The Reaction between Sodium Chloride Solution and XX1X.-The Theory of Duplex Affinity. By SAMUEL HENRY CLIFFORD BRIQGS . 278 XXX.-Curcumin. By PRAPHULLA CHANDRA GHOSK . 292 XXX1.-The Rotatory Dispersive Power of Organic Com-pounds. Part IX. Simple Rotatory Dispersion in the Terpene Series. By THOMAS MARTIN LOWRY and HAROLD HELLING ABEAM .. 300 By SAMUEL JUDD LEWIS . . 312 PAGE Netallic Magnesium. By WILLIAM HUGHES . . 272 XXXI1.-A New Sector Spectrophotometer CONTENTS. V PAGE XXXIII. -The Formation and Stability of spiro-Compounds Part 11. Bridged-spi7.o-compounds Derived from cyclo-Hexane. By CHRISTOPHER KELK INGOLD and JOCELYN FIELD THORPE . ANNUAL GENERAL MEETIXG . PRESIDENTIAL ADDRESS . OBITUARY NOTICES . XXX1V.-Porphyroxine. By JITENDRA NATH KAESHIT . XXXV.-Coagulation of Metal Sulphide Hydrosols. Part I. Influence of Distance between the Partieles of a Sol on its Stability. Anomalous Protective Action of Dissolved Hydrogen Sul phide. By J~~ANENDRA NATH MUKHERJEE and NAJENDRA NATH SEN. . XXXVL-A Simple Form of Apparatus for Estimating the Oxygen Content of Air from the Upper Atmosphere.By FRANCIS WILLIAM AsTos . XXXVI1.-The Resolution of Hyoscine and its Components, Tropic Acid and Oscine. By HABOLD KING . XXXVII1.-The Basic Properties of Oxygen in Organic Acids and Phenols; and' the Quadrivalency of Oxygen. By JOSEPH KNOX and MARION KNOX RICHARDS XXXIX.-+-l 8-isoNaphthoxazones. By BIMAN BIHARI DEY and MAHENDRA NATH GOSWAMI . XL.-Mercury Mercaptide Nitrites and their Reaction with the Alkyl Iodides. Part V. Chain Compounds of Sulphur (continued). By SIR PRAFIJLLA CHANDRA RAY and PJ~AFULLA CHANDRA GUHA . . 0 XLI.-Mercury Mercaptide Nitrites and their Reaction with the Alkyl Iodides. Part VP. Chain Compounds of Sulphur (continued). XLIL-Nerctwic Sulphoxychloride. By SIR PRAFCLLA CIIANDRA RAY and PRAFULLA KUMAR SEN .XLII1.-The Preparat ion of Cadmium Suboxide. Ey HEXRY GEORGE DENHAM . . XL1V.-Formation of Diphenyl by the Action of Cupric Salts on Organornetallic Compounds of Magnesium By JACOB RRIZEWSKY and EUSTACE EBENEZER TURNER OBITUARY NOTICE . . . . . XLV.-Studies on the Dependence of Optical Rotatory Power on Chemical Constitution. Part I. Position-Isomerism and Optical Activity of Naphthylihinocamphors and Deriva-tives of Phenyliminocamphor . By BAWA KARTAR SINGH and JATINDRA KUMAR MAZUMDER . XLV 1 .-The Nitration of Dipheriylethylenediamine. Ey GEORGE . By SIR PRAFULLA CHANDRA RAY . . nr.4CDONALD BEENETT . . 320 384 397 408 455 461 472 4'76 508 53 1 541 548 55'3 556 559 56 2 566 57 Vi CONTENTS XLVI1.-The Propagation of Flame in Mixtures of Acetylene and Air.By WALTER MASON and RICHARD VERNON WHEELER . . 578 XLVII1.-The Preparation of Diacetonamine. By ARTHUR ERNEST EVEREST . . 588 XL1X.-The Constitution of Maltose. A New Example of Degradation in the Sugar Group. By JAMES COLQUHOUN IRVINE and JAMES SCOTT DICK . * 593 L.-Catalytic Racemisation of Ethyl I-Mandelatos. By ALEX. MCKENZJE and HENRY WREN . . 602 L1.-The Potential of a Nit+ogen Electrode. By FRANCIS LAWRY USHER and RAMAVENKATASUBBIER VENKATESWARAN . . 613 LI1.-A Chemical Investigation of Banded Bi tuminoiis Coal. Studies in the Composition of Coal. By FREDERICK VINCENT TIDESWELL and RICHARD VERNQN WHEELER . . 619 LII1.-The Rotation-dispersion of Butyl Heptyl and Octyl Tartrates.By PEricy FARADAY FRANKLAND and FREDERIC HORACE GAEKER . . 636 L1V.-The Tannin of the Canadian Hemlock (Tszrya cunudensis, Carr). By RODGER JAMES MANNING and MAXrMILrAN NIERENBTEIN . . 662 LV.-The Formation of Dinzonmino-compounds from P-Nsphthyl-amine. Ey GEORW MARSHALL NORMAN . . 673 LTfI.-The Chemistry of the Glutaconic Acids. Part XI. The Occurrence of 1 3-Addition to the Normal Form. By JOCELYN FIELD THORrE . . 679 LVI1.-The Formation and Reactions of Imino-compounds. Part XIX. The Chemistry of the Cyanoacetamide and Guareschi Condonsntions. By GEORGE ARMAND ROBERT KON and JOCELYN FIELD THORPE . . 686 LVII1.-"Blue John" and other Forms of Fluorite. By BERTRAM BLOUNT and JAMES HARRY SEQUEIRA . . 705 L1X.-Studies in Catalysis. Part XI. The Le Chstelier-Braun Principle from the Point of View of the Radiation Hypo-thesis.By WILLTAM CUDMORE MCCULLAGH LEWIS . . 710 LX.-Cryptopine. Part 11. By WILLIAM HENRY PERKIN jun. 713 LX1.-The Freezing Point of Solutions with Special Reference to Solutions Containing Several Solutes. By CHARLES EDWARD FAWSITT . . 790 LXI1.-The Use of Freezing-point Determinations in Quantita-tive Analysis. By CHARLES EDWARD FAWsrTT . . 801 LX1II.-The Constitution of the Disaccharides. Part 111. Maltose. By WALTER NORMAN HAWORTH and GRACE CUMMING LJCITCH . . 809 PAG CONTENTS. vii PAGE LX1V.-Condensation of Deoxybenzoin and Aldehydes. By ANANDA KISORE DAS and BROJENDRA NATH GHOSH LXV.-Condensation of Deoxybenzoin with Aromatic Aldehydes. By BAWA KARTAR SINGH and JATINDRA KUMAR MAZUHDER .LXVI. -Trustworthiness of the Balance ovar Long Periods of Time. By GEORGE DEAN . LXVI1.-The Isomeric Tropic Acids. By ALEX. MCKENZIE and JOHN KERFODT WOOD . . LXVIIL-The Absorption Spectra of the Nitric Esters of Glycerol. By HARRY HEPWORTH . LX1X.-The Interaction of Acetylene and Mercuric Chloride. By DAVID LEONARD CHAPMAN and WILLIAM JOB JENKINS . LXX.-The Basic Properties of Phenanthraquinone. By JOSEPH KNOX and HELEN REID WILL . LXXI.-The Solubility of Silver Acetate in Acetic Acid and of Silver Propionate in Propionic Acid By JOSEPH KNOX and HELEN REID WILL . A Lecture Delivered By JOHN The Quantum Theory and New Theories of Atomic Structure. A Lecture Delivered before the Chemical Society on May lst, 1919. By JAMES HOPWOOD JEANS ..1,XXII.-Interaction of Mercuric and Cupric Chlorides Respec-tively and the Mercaptans and Potential Mercaptans. By Sir PRAFULLA CHANIIRA RAY . . . ANNUAL REPORT OF THE INTERNATIONAL COMMITTEE ON ATOMIC WEIGHTS . . LXSII1.-The Presence of Aconitjc Acid in Sugar-cane Juice and a New Ileaction for the Detection of the Acid. By CHARLES SOMERB TAYLOR . LXX1V.-Studies in the Camphane Series. Part XXXVII. Aryl Derivatives of Imino- and Amino-camphor. By MARTIN ONSLOW FORSTER and HANS SPINNER LXXV.-The Oxidation of Coal. By FREDERICK VINCENT TIDESWELL and RICBARD VERNON WHEELER LXXV1.-The Catalytic Reduction of Hydrogen Cyanide. By SYDNEY RARRATT and ALAN FRANCIS TITLEY . LXXVIL-The Chemistry of Butpindy Mixtiires. By ROBERT LUDWIG MOND and CHRISTIAN -HEBERLEIN LXXVII1.-Examination of the Bark of Croton gzcbouga.Isola-tion of 4-Hydroxyhygric Acid. By JOHN AUQUSTUS GOODSON and HUBERT WILLIAM BENTLEY CLEWER . LXX1X.-Hnrmine and Harmaline. Part 111. By WILLIAM HENRY PERKIN jun. and ROBERT ROBJNSON . Emission Spectra and Atomic Structure. before the Chemical Society on March 6th 1919. WILLTAM NICHOLSON . 4 . . . . 817 821 826 828 840 847 850 853 855 865 871 879 886 889 89 5 902 908 923 93 ... V l l l CON’I’ENTS. LXXX.-€Earmine and Harmaline. Part IV. BY WILLIAM LXXX1.-A New Photographic Phenomenon. By DONALD LXXXI1.-The Stereochemistry of Hyoscine. By HAROLD LXXXII1.-Substituted Phenylarsinic Acids and their Reduc-tion Products and the Estimation of Arsenic in such Cornpounds.By ROBERT GEORGE FARGHER . . 982 LXSX1V.-The Selective Combustion of Carbon Monoxide in Hydrogen. By ERIC KEIGHTLEY RIDEAL . . 993 LXXXV.-The Temperature of Explosion for Endothermic Substances. By RASIR LAL DATTA and NIHAR BANJAN CHATTERJEE . . 1006 LXXXV1.-The Preparation of Buty-lamine and of n-Dibutyl-amine. The Separation of Aliphatic Amines by Partial LXXXVI1.-The Abnormal Behaviour of Glyoxalinecarboxylic PAGE HENRY PEHKIN jun. and ROBERT ROBINSON . . 96‘5 NEIL MCARTHUR and ALFRED WALTER STEWART . 973 KING . . 974 Neutralisation. By EMIL ALPHOSSE WERNER . . 1010 Esters and Anilides towards Diaxonium Salts. By ROBERT GEORGE FARGHER and FRANK LEE PYMAN . . 1015 LXXXVIIL-The Free Energy of Dilution of Aqueous Sodium Chloi-ide Solutions.By ARTHUR JOHN ALLMAND and WILFRID GUSTAV POLACK . . 1020 LXXX1X.-The Active Substance in the Todination of Phenols. By VICTOR COFMAN . . 1040 XC.-The Influence of Hydrogen Sulphide on the Occlusion of Hydrogen by Palladium. By EDWARD BRADFORD MASTED . 1050 XCI .-The Critical Solution Temperature of EL Ternary Mixture as a Criterion of Purity of Toluene. By KENNEDY JOSEPH PREVITI~ ORTON and DAVID CHARLES JONES . . 1055 XCIL-Thiocyanoacetone and its Derivatives and Isomericles. By JOSEPH TCHERNIAC . . 1071 XCII1.-An Automatic Extraction Apparatus. By JOSEPH TCRERNIAC . . 1090 XC1V.-The Constitution of Carbarnides. Paat IX. The Inter-action of Nitrous Acid and Mono-substituted Ureas. The Preparation of Diazomethane,’ Diazoethane Diazo-n-butane, and Diazoisopentane from the Respective Nitroso-ureas.By EMIL ALPHONSE WERNER . . 1093 XCV.-Dyes Derived from Quinolinic Acid. By PRAPHULLA CHANDRA GHOSH . . 1102 XCV1.-Sodium Hypochlorite. By MALCOLM PERCIVAL APPLEBEY . . 1106 XCVI1.-Capsaicin. Part I. By ARTHUR LAPWORTH and FRANK ALBERT ROYLE . . 110 CONTENTS. ix PAGE XC V1II.-The Vapour Pressures and Densities of Mixtures of Acetone and Methyl Ethyl Ketone. By TUDOR WILLIAMS PRICE . . . 1116 XC1X.-The Constitution of Internal Diazo-oxides (Diazo-phenols). Part 11. By GILBERT T. MORGAN and ERIC DODDRELL EVENS . . 1126 C.-P-Naphthylmethylamine. By GILBERT T. MORGAN and FREDERICK PAGE EVANS . . 1140 CI.-Action of Phenylhydrazine on Phthalalclehydic and Phthalonic Acids Phen yl-hydrazo- and Azo-Phthalide.By PRAFULLA CHANDRA MITTER and JNANENDRA NATH SEN 1145 CI1.-Nercury Mercaptide Nitrites and their Reaction with the Alkyl Iodides. Part VII. Chain Compounds of Sulphur (contiw~wcl). By Sir PRAFULLA CHANDRA RAY and PRAFULLA CHANDRA GUHA . . . 1148 CII1.-Asymmetric Replacement in the meta-Series. Part I. By WILLIAM HENRY GOUQH and JOCELYN FIELD THORPE . 1155 C1V.-Molecular-weigh t Determination by Direct Measurement of the Lowering of the Vapour Pressure of Solutions. By ROBERT WRIGHT . . . . 1165 CV.-The Constitution of Carbamides. Part X. The Behaviour of Urea and of Thiourea towards Diazomethane and Diazo-ethane respectively. The Oxidation of Thiourea by Potass-ium Permanganate. By EMIL ALPRONSE WERNER . . 1168 CV1.-The Tannin of the Knopper Gall.By MAXIMILIAN NIERENSTEIN . . 1174 CVI1.-The Oxidation of Phenol Derivatives. By CYRIL NORMAN HTNSHELWOOD . . 1180 CVIT.1.-Chloropicrin. Part I. By JOHN ADDYMAN GARDNER and FRANCIS WILLIAM Fox . . 1185 CIX.-The Temperature of Critical Solution of a Ternary Mix-ture as a Criterion of Purity of m-Butyl Alcohol. The Preparation of pure n-Butyl Alcohol. By KENSEDY JOSEPH PREVITB ORTON and DAVID CHARLES JONES . . 1194 CX.-The Action of Grignard Reagents on the Esters of certain Dicarboxylic Acids. By HARRY HEPWORTH . . 1203 CXT.-The Melting Points of the Substituted Amides of the Normal Fatty Acids. By PHILIP WILFRED ROBE~TSON . 1210 CXI1.-The Effect of Sea-salt on the Pressure of Carbon Dioxide and Alkalinity of Natural Waters. By EDMUND BIXYDGES RUDHALL PRIDEAUX .. 1223 CXII1.-The Rate of Hydrolysis of Methyl Acetate by Hydro-chloric Acid in Water-Acetone Mixtures. By GEORGE JOSEPH BURROWS . . 123 X CONTENTS. CXIV. -The Velocities of Combination of Sodium Derivatives of Phenols with Olefine Oxides. Part 11. By DAVID RUNCINAN BOYD and DORIS FELTHAM THOMAS . . 1239 CXV.-Molecular Refractivity of Cinnaruic Acid Derivatives. By ERIC WALKER and THOMAS CAMPBELL JAMES . . 1243 CXV1.-The Determination of Ignition-temperatures by the Soap-bubble Method. By ALBERT GREVILLE WHITE and TUDOR WILLIAMS PRICE . . 1248 The Influence of Mass. By DAVID LEONARD CHAPMAN and JOHN REGINALD HARVEY WHISTON . . 1264 CXVII1.-Auto-complexes in Solutions of Cupric Chloride and Cupric Bromide. By STEWART BYRON WATE~N~ and HENRY GEORGE DENHAM .. . . 1269 By JAMES WILLIAM MCBAIN MARY EVELYN LAING and ALAN FRANCIS TITLEY . . 1279 CXX.-The Degree of Hydration of the Particles which Form the Structural Basis of Soap Curd Deterpined in Experi-ments on Sorption and Salting Out. By JAMES WILLIAM MCBAIN and MILLICENT TAYLOR . . 1300 CXX1.-Reaction of the Potassium Salts of 2-Thiol-5-thio-4-phenyl-4 5-dihydro-1 3 4-thiodiazole and 2 5-Dithiol-1 3 4-thiodiazole with Halogenated Organic Compounds. By PRAFULLA CHANDRA RAY PRAFULLA CHANDRA GUHA, and RADHA KISBEN DAS . . 1308. CXXI1.-Equilibria Across a Copper Ferrocyanide and an Amy1 Alcohol Membrane. By FREDERICK GEORQE DONNAN and WILLIAM EDWARD GARNER . . 1313 CXXII1.-The Colouring Matter of the Red Pea Gall By MAXIMILIAN NIERENSTEIN .. . . . 1328 CXX1V.-The Effect of Salts on the Vapour Pressure and Degree of Dissociation of Acetic Acid in Solution. An Experimental Refutation of the Hypothesis that Neutral Salts Increase the Dissociation Constants of Weak Acids and Bases. CXXV.-Some Ternary Systems containing Alkali Oxalates and Water. By ALBERT CHERBURY DAVID RIVETT and EDMUND ARTHUR O'CONNOR . . . 1346 CXXV1.-The Decomposition of Carbamide in the Presence of Nitric Acid. By TUDOR WILLIAMEI PRICE. . . 1354 CXXVI1.-Studies in Catalysis. Part XII. Catalytic Criteria and the Radiation Hypothesis. By M71LLIAM CUDNORE MCCULLAQH LEWIS . . 1360 CSXVII1.-Criteria of the Degree of Purity of Commercial Toluene. By JOHN SCOTT LUMSDEN. . . 1366 PAGE CXVI1.-The Interaction of Chlorine and Hydrogen.CXIX.-Colloidal Electrolytes Soap Solutions as a Type. By JAMES WILLIAM MCBAIN and JAMES KAM . 133 CONTENTS. xi PAGE CXX1X.-1 3-Bonzodiazolearsinic Acids and their Reduction Products. By ROBERT REGINALD BAXTER and ROBERT GEORGE FARGHER . . 1372 CXXX.-The Equilibrium between Carbon Hydrogen and Methane. By HUBERT FRANK COWARD and STANLEY PIERCE WILSON. . . 1380 CXXX1.-The Properties .of Ammonium Nitrate. Part I. The Freezing Point and Transition-temperatures. By REGINALD GEORGE EARLY and THOMAS MARTIN LOWRY . 1387 CXXXI1.-The Production of Methyl Ethyl Ketone from n-Butyl Alcohol. By ALBERT THEODORE KING . . 1404 CXXXIIL-Conversion of the Simple Sugars into their Enolic and Ethylene Oxide Forms. By EDWARD FRANKLAND ARMSTRONQ and THOMAS PERCY HILDITCH. . . 1410 CXXX1V.-The Constitution of the Nitroprussides. Part I. Conductivity and Cryoscopic Measurements. By GEORGE JOSEPH BURROWS and EUSTACEBENEZER TURNER . . 1429 CXXXV.-The Propagation of Flame in Complex Gaseous Mixtures. Part I. Limit Mixtures and the Uniform Movement of Flame in such Mixtures. By WILLIAM PAYMAN . . 1436 CXXXV1.-The Propagation of Flame in Complex Gaseous Mixtures. Part 11. The Uniform Movement of Flame in Mixtures of Air with the Paraffin Hydrocarbons. By WILLIAM PAYMAN . . 1446 aXXXVII.-The Propagation of Flame in Complex Gaseous Mixtures. Part 111. The Uniform Movement of Fhme in Mixtures of Air with Mixtures of Methane Hydrogen and Carbon Monoxide and with Industrial Inflammable Gases. CXXXVIIL-The Ignition of Ether-Alcohol-Air and Acetone-By ALBERT CXXX1X.-The Conductivities of Iodoanilinesulphonic Acids. By WILLIAM PAYMAN. . . 1454 Air Mixtures in Contact with Heated Surfaces. GREVILLE WHITE and TUDOR WILLIAMS PRICE . . 1462 BY MARY BOYLE . . 150

ISSN:0368-1645    

DOI:10.1039/CT91915FP001

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

J O U R N A L OF THE CHEMICAL SOCIETY, TRANSACTIONS. A. CHASTON CHAPMAN. A. W. CROSSLEY,C.M.G.,D.SC.,F.R.S. SIR JAMES J. DOBBIE M.A. D.Sc., M. 0. FORSTER D.Sc. Ph.D. F.R.S. ‘J!. A. HENRY D.Sc. J. T. HEWITT M.A. D.Sc. Ph.D., F.R..S. F.R. S. C. A. KEANE D.Sc. Ph.D. T. M. LOWRY O.B.E.,D.Sc. F.R.S. G. T. MORGAN D.Sc. F.R.S. J. C. PHILIP 0 . B E. D.Sc. Ph.D. A. SCOTT M.A. D.Sc. F.R.S. S. SMILES O.B.E. D.Sc. F.R.S. J. I?. THORPE C.B.E. D.Sc. Ph.D. F. R. S. @Yiur : J. C. GAIN D.Sc. SltXr- &bitrrr : A. J. GREENAWAY. ,2Jwwirrtrrtrt Snb-&bitiYr : CLARENCE SMITH D.Sc. 1919. Vol. CXV. Part II. pp. 713-end LONDON : GURNEY & JACKSON 33 PATERNOSTER ROW E.C. 4. 1919 PRINTED IN GREAT BRITAIN BY RICHARD CLAY & ~ O N S LIMITED, BBUNSWICK ST. STAMFORD ST. S.E. 1, AND BUNOAY SUFFOLK

ISSN:0368-1645    

DOI:10.1039/CT91915FP015

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

DILUTION LIMITS OF INFLAMMABILITY OF GASEOUS MIXTURES. 27 1.-The Dilution Limits of In$ummability of Gaseous Mixtures. Part III. The Lower Limits of some Mixed Injarrimable Gases with Air. Part IV. The Upper Limits of some Gases Singly and Mixed in Air. By HUBERT FRANK COWARD CHARLES W~LLIAM CARPENTER and WILLIAM PAYMAN. PART 111. IN Part I of this series of papers (Coward and Brinsley T. 1914, 105 lS59) the wide variation in the values assigned by different observers to the limits of inflammability of hydrogen and other gases in air was shown to be due to the very different criteria of inflammability used. The meaning of the term " inflammability " was therefore discussed and it was concluded that inflammability could and should be regarded as a characteristic property of a gas mixture apart from the precise nieans used f o r ignition and from the form of the vessel that might happen to bel chosen for experimelnt.It was argued that a gaseous mixture should be termed inflamniabls per se a t a stated temperature and pressure if and only i f it were capable of indefinih self-propagation of flame while1 the unburnt portion of the mixture was maintained a t the stated temperature and pressure.;+ I n Part I1 (T. 1914 105 1865) the1 lower limits of inflamma-bility of hydrogen methane and carbon monoxide individually in air were examined experimentally by means of apparatus speci-ally designed to enable1 the progress of flame to be observed in much wider and longer vessels than had been hitherto employd.Jr The presemtl paper records the results of experiments carried out to determine the lower limits in air of various mixtures of hydrogen methane and carbon monoxide taken two a t a time or * This definition has been discussed by Burgess and Wheeler (T.1914, 105 2591). Several other papers on the subject of " dilution limits of in-flammability ¶ ' have appeared since Coward and Brinsley's paper was published but as they have not been concerned with the question of indefinite propagation of flamc but mercly with tho inflammation of very liinitod ninount,~ of gasoous mist;lircs they 1ia.w no direct bearing on tho present inquiry. f Burell and Oberfell (U.S.A. Bureau of Mines Y'echrhicwl Paper No. 119 1915) havo adopted a oudiomster of the same Eiize 8s that used by Con.nrc1 and Brinsloy 28 COWARD CARPENTER AND PAYMAN THE DILUTION LIMITS all three together and finally of the complex mixture a “town’s gas.” A simple formula of purely additive character has been put forward by Le Chatelier to connect the lower limita of single gases with the lower l’ta of mixtarea of them.This formula origin-ally limited to binary mixtures is generalised thus: = 1. where N, N2 Ar3 . . . are the lower limits in percentages of the whole air mixture for each combustible gas separately nl n2, m3 . . . are the proportions in percentages of the whole air mix-ture of each combustible gas a t the dilution limit. The percentage of total combustible gas present in the limit mixture is thus This formula enables the lower limit L of a combustible mix-ture to be calculated from the dilution limits of its several con-stituents.I f the proportions of each of the combustible con-stituents are pl p2 p3 . . . so that pl+p2+p3+ . . . =loo a simple transformation gives its dilutdon limit in air as L = T + m 2 + % + . . . The physical meaning of the formula may be best appreciated by the consideration of a particular case. A mixture of air carbon monoxide and hydrogen which contains onequarter of the amount of carbon monoxide necessary to form a lower limit mixture, together with three-quarters of the amount of hydrogen necwsary, will be a lower limit mixture. In other words the lower limits of inflammability form a series of inflammability equivalents for the individual gases of a mixture. It may also be deduced from the formula that lower limit air mixtures if mixed in any proportions give rise to mixtures which are also a t their lower limits.Experimental support for the formula rests on observations by Le Chatelier ( A n m . des Mimes 1891 [viii] 19 388) with three mixtures of methane and coal gas by Ls Chablier and Boudouard (Compt. rend. 1898 126 1344) with three mixtures of hydrogen and carbon monoxide and with one mixture of aaetylene and carbon monoxide and by Eit’ner (Habilitationsschrift Miinchen, 1902) with hydrogen and carbon monoxide in equal volumes and with coal gas. The difference between the calculated and the observed dilution limits rarely reached one twenty-fifth part o OF INFLAMMABILITY OF GASEOUS MIXTURES. PAET 111. 29 the combustible mixture.None of these experiments however, was carried out in apparatus large enough to indicate whether the mixtures used were capable of continued propagation of flame. Thus Le Chatelier and Boudouard used for the lower limit of hydrogen ifi air the figure 10 per cent. whereas the recent experi-ments have shown that mixtures containing upwards of 4.1 per cent. of hydrogen are capable of propagating flame apparently indefinitely in an upward direction. Le Chatelier had in fact, found that the 10 per cent. hydrogen mixtare was the weakest which would propagate flame downwards through a somewhat narrow tubel. It is only necessary to ignite from below to produoe a self-propagating flame in mixtures considerably weaker in hydrogen. The experiments now t o be described were therefore carried out in the eudiometer previously described (Coward and Brinsley Zoc.cit.) 1.8 met’rres (6 feet) in length and 30 cm. (1 foot) square in section with a capacity of 170 litres. In each case the mixtures under experiment were saturated with moisture a t 18-19O and were maintained a t approximately atmospheric pressure during inflammation. The source of ignition was a spark gap of variable length between small platinum spheres. A 6-inch Apps coil with two four or six storage oells was used t o produce single sparks. The various gases were pre-pared in a state of purity and each mixture with air was made to the desired composition which was checked by the analysis of samples taken just before firing. E X P E R I M E N T A L . The lower limits of a number of mixtures of hydrogen carbon monoxide and methane taken two or three together and also of a “itown’s gas,” are recorded in table I (p.30) together with the lower limits calculated by means of the Le Chatelier formula from the limits of the individual gases. Several of the experimental results differ from those calculated by amounts exceeding the errors of observation and experiment; nevertheless the formula givw a useful approximation over the whole range of mixtures examined and may be applied therefore, to water gas and to coal gas as well as to town’s gas. The most striking anomaly was shown by the mixture contain-ing 10 per cent. of hydrogen and 90 per cent. of carbon monoxide, where the large difference was in the opposite direction to that usually noted.This anomaly was more pronounced in experi-ments with the same mixture in a narrower tube (5 cm. diameter) 30 COWARD CARPENTER AND PAYMAN THE DILUTION LIMITS TABLE T . Composition of gas (before admisture with air). TAower limit, of iiiflainmability in air. Carbon Hydrogen. monoxide. 100 -75 25 50 50 26 75 1 0 90 I 0 0 100 -33.3 33.3 55 15 ” Town’s gas ” Methane. ----1 0 25 50 60 75 100 76 50 25 10 -33.3 30 Observed. Per cent. 4.1 4.7 6.03 8-2 10.3 12-5 11.0 9.6 7 . 7 7.2 6.4 5.6* 4.7 4.6 4.1 4.1 4.1 5-7 4.7 5.35 Calculateti. Per cent. I 4.9 6.2 8.3 10.4 __ 1 1 . 1 !).ci 7.7 7-1 6.5 I 5.0 4.7 4.4 4.2 -6.0 5.0 5-36; DiHerenco.Per cent. -- 0.2 -0.15 -0.1 + 0.4 - .--0.1 -0.1 0.0 +o-1 - 0.1 -- 0.3 -0.1 - 0.9 -0.1 -- 0.3 - 0.3 0.0 * This figure is choeen rather than the lower value given by Coward and Brinsley (Zoc. cit. p. 1885) for the reason stated on page 1877 of that paper : “ . . . the flames of mixtures containing 5-3 to 5.6 per cent. of methane are very sensitive t o extinction by shock . . . a 5-6 per cent. mixture will invariably propagate flame when the shocks are no greater than those occa-sioned by the somewhat violent bubbling of gas through water . . . (but) when the circumstances are such that a tranquil passage is rtssured 5-3 per cent. is the lower limit of inflammability of methane in air.” In none of the present experiments with methme mixtures did we observe the curious tranquil passage of flame noted with the 5.3 per cent.methane mixture so that 6.6 per cent. seems the correct figure to employ for calculations in con-nexion with these experiements. C0,=2.6. 02=0-5. C,H etc.=2.8. CO= 14.1. H,=46.6. CH,=19.4. C,€&=4-0. N,=9.2 per cent .The benzene etc. vapours were estimated by the deter-mination of their partial pressures by Burrell and Robertson’s method (J. Ind. Eng. Chem. 1915 7 669). For calculating this figure the following lower limits of the individual gases were used Hydrogen carbon monoxide and methane &s in table I, ethylene 3.4 per cent. (Eitner) ethane 3-1 per cent. (Burgess and Wheeler), benzene 1.4 per cent. (Kubierschky). The last three values represent results obtained in small vessels but may probably be safely used in view of the comparatively small amounts of the three gases present in the “ town’s gas.” The non-inflammable constituents of the town’s gw amounted to 12.3 t Composition of the “ town’sgas ” CdHI etc.vapours=O*8 OF INFLAMMABILITY OF GASEOUS MIXTURES. PART 111. 31 A brief reference to the general character of the flames is necessary. Inflammable mixtures rich in hydrogen including the town's gas gave thin vortex rings of flame increasing in diameter as they rose through the first 30 or 40 cm. and then breaking into luminous segments which subdivided into balls of flame. The latter rose increasing in number to the top of the vessel. The flames in mixtures somewhat below the lower limit were extinguished a t s m 0 stage of their journey.The flames of these mixtures showed in fact similar behaviour to t.hose described by Coward and Brinsley for pure hydrogen but the luminosity was much enhanced. Inflammable mixtures containing no hydrogen gave thick rings which as they progressed developed into flames of strongly convex front spreading from side to side of the box; similar mixtures just below the limit of inflammability gave rings of flame breaking into striae which were extinguished in the next 50 or 100 cm. of their journey. The appearance of all the flames of mixtures is apparently compounded additively of those of the individual components. There was no difficulty in deciding upon the figure for the limit within about 0.1 per cent.Conchions (Part 111.). The lower limits of inflammability in air of mixtures of hydrogen carbon monoxide and methane taken two a t a time or all together and also the lower limits of wat,er gas coal gas and town's gas may be calculated with approximate accuracy from t.he lower limits of the individual gases by means of L e Chatelier's formula. PAXT 1v. The Upper Limits of some Gases Siiigly and Mixed in Air. The upper limits of inflammability of hydrogen methane and carbcon monoxide severally in air have been investigated by a number of observers; their results are quoted in T. 1914 105, 1859. The hydrogen figures show t.he greatest range of variation, namely from about 55 t o 80 per cent. of hydroge'n. The methane figurw mostly lie bet.ween 12 and 17 per cent'.of methane and per cent. which on the lower limit mixture represents only 0.66 per cent. of the whole. In view of the known slight influence on the lower limit of methane of the substitution of small amounts of carbon dioxide or nitrogen for equal amounts of air it is safe to assume for the purposes of the calculation that the non-inflammable constituents of coal gas (and likewise of water gas) can bo treated as air 32 COWARD CARPENTER AND PAYMAN THE bfLUTfON LIMITS the carbon monoxide figures are in the neighbourhd of 75 per cent. of carbon monoxide. The Upper Limit of Hydrogen .-Some preliminary experiments were conducted with the object of discovering whether the flames in mixtures just below the upper limit resembled the flames in mixtures just above the lower limit.If so the apparent dis-crepancies between the resulk3 of earlier workers might be ex-plained on the same lines as the discrepaiicies noted in lower limit figures. It was soon evident however that comparatively weak or short electric sparks which were quite strong enough to ignite lower limit mixtures were unable to inflame upper limit mixtures. Stronger sparks in the lataker mixtures started flames which travelled throughout the whole mixture. This promised a clue to the main cause of discrepancy of the results of others and by the use of igniting sparks of such variable strength as might well have been employed in ordinary laboratory practice a range of results was obtained nearly as wide as those of the previous un-correlated list.The experiments were carried out. in a half-litre globe with a spark of variable length in the centre. A 6-inch Apps induction coil was used with a constant break and the current in the primary was varied by using a battery of 2 to 12 volts. We have to acknowledge our indebtedness to Mr. F. Brinsley for conducting this series of experiments the results of which are recorded in table 11. TABLE 11. Percemtage of Hydrogen in Apparent Upper Limit Air Mixture. Spark gap. 2 4 1 mm. 57.5 -2 4 8 70.2 70.7 16 20 32 46 56 - -- -- -I -- - - -- -8 67.0 70.2 7 1-2 7 1-2 72.5 73.5 73.5 --Voltage of accumulators. __7 --/--_ 12 ---72.2 74.5 75-5 -I -These figures suggest an upper limit of ydrogen-a,r mixtures in the neighbourhd of 75.5 per cent.of hydrogen but the volume of gas used was much tnoo small to indicate whether the flames observed were capable of indefinite self-propagation. Further-more the gases were confined and so were not maintained under constant pressure during inflammation FIG. 1. Hydrogen. FIG. 3. FIG. 2. S4etlzune. FIG. 4 Methane and carboil. inonoxide mixture. Upper linzit Jlames in tube of 5 em. diameter. [Yo J h c e page 33 OF INFLAMMABILITY OF QASEOUS MIXTURES. PART IV. 33 A series of experiments was therefore carried out in a 15-litre bell-jar just dipping under the surface of water with a spark gap near t'he botltom of thel mixture. With a suitable single spark, ignition was obtained with mixtures containing 73.1 73.8 and 74.0 per cent.of hydrogen but failed with 74.4 and 75.0 per cent. of hydrogen. The flames travelled rapidly throughout the whole mixture. The limit indicated was thus approximately 74.2 per cent. of hydrogen. The next step in determining the true limit fosr continued pro-pagation of flame was the use of long vessels. A tube 1.5 metres long and 5 cm. wide was used. Flame travelled rapidly through this tube with mixtures containing 71.2 and 71.4 per cent. of hydrogen. The appearance of this flame is indicated in Fig. 1. Mixtures containing 71-6 and 73.0 per cent. could not be ignited, or if ignited the flame was extinguished before it had travelled more than a felw cm. from the spark. I n order to fix the upper limit precisely it would be necessary to use vessels of dimensions comparable with those of the box previously described.This would involve the construction of a much stronger vessel than the one available but a t the time this was contemplated the experimenh had to be abandoned and oppo'rtunities for continuing them will not be available in the near f uture. It is however certain that the upper limit of hydrogen is some-what higher than 71.5 per cent.; it is probably near to 74.2 per cent. The Upper Limit of Methane.-In the 15-litre bell-jar mixtures containing 15.1 and 15.3 per cent. of methane propagated flame, of a reddish-brown colour edged wihh blue upwards throughout the mixture. A 15.5 per cent. mixture could not be ignited but when a rapid succession of sparks was passed a blue flame-cap was observed above them.I n the 1-5-metre tube mixtures containing 14.4 14.7 15.0 and 15.1 per cent. of methane propagated flame throughout the tube; with a 15.2 per cent. mixturel a flame was initiated but was extinguished after pas3i.n-g some pn. up the tuba. I n each case, the flame seemed to consist of two distinct portions the upper-most blue with a convex front followed by a reddish-brown conical tail which suggested a secondary reaction of combustion (see Fig. .2). The limit for indefinite propagation is therefore more than 15.1 per cent. and probably approaches 15.4. This conclusion is supported by the experiments of Burrell and Oberfell (Zoc. cit.) who used for upper limit experiments on methane an iron pipe 30 cm. (12 inches) in diameter 2.1 metres VOL.cxv. 34 COWARD CARPENTER AND PAYMAN THE DILUTION LIMITS (7 feet) high with a series of glass windows. Their experimelli:; showed the upper limit to lie between 15.0 and 15.4 per cent. for upward propagation of flame. The Upper Limit of Carbom Monoxide.-In the 15-litre bell-jar flames travelling rapidly upwards through the whole of the mixture were obtained when 73.7 and 74-0 per cent. of carbon monoxide was present. Flameis were initiated in 74.5 and 75.0 per cent. mixtures but were extinguished after travelling a short distance. A 75.2 per cent. mixture gave only a blue halo round the spark. I n the 1.5-metre tube a flame travelled up through a 72.9 per cent. mixture but no more than a tongue of flame1 was obtained with a 73.1 per cent.mixture. The walls of the tube evidently exerted a notable cooling influence. The1 self -propagating flame had a strong convex front was blue with a bright whitish-blue edging but had no “tail,” as was the case with methane flames (see Fig. 3). The limit for indefinite propagation is therefore more than 73.0 per cent. and probably approache? 74.3 per centl. Apjdiicability of the Mixture Law t o Upper Limits of Inflammability . The additive character of the lower limih of inflammability was expressed by Le Chatelier in a formula quoted above (p. 28). The validity of a similar formula for t h e upper limits of mixeld combustible gases-in air has been obscured by experiments with hydrogen-air mixtures in which the sparks were insufficiently strong and therefore the figures obtained represented not the limiting composition for the propagatioln of flame but the limiting cmposibion for the initiation of flame by the sparks in use.It is shown below that t;he following formula holds approximately for the upper limits of mixtures of hydrogen methanel and carbon monoxide two or three a t a time;: where nl % . . . represent the proportions in percentages of the whole air mixture of each combustible’ gas a t the upper limit, N, N . . . represent thel upper limits in percentages of the whole air mixtnre of each combustible gas separately. F o r reasons stated abolve the experimental apparatus available did not combine the desirable width with the desirable length, and the choice lay between a bell-jar and a longer but narrowe OF INFLAMMABILITY OB' GA!E%OUS MIXTURES.PART IV. 35 glass tube (1.5 metres long 5 em. iii diameter). The latter was chosen because it enabled a flame to be ubserved travelling far enough from the original source of ignition; the disadvantage of narrowness was not great for the limits observed in the tube were lower than those indicated by the wider bell-jar by a not very considerable amount. (For hydrogen 2.7 on 74.2 per cent.; for methane 0.25 on 15.4 per cent..; for carbon monoxide 1.2 on 74-2 per cent.) The limits observed in the tube are recorded in table 111. TABLE 111. Percentage composition of gas (before admixture Upper limit of inflammability in air. with air) ,- A \ I \ Calcu- Differ. - 7 1.5 CH,. CO. Observed. lated.ence. - I H,. -- I 100 Single gases ... - 100 - 15.1 - - - 100 73.0 I 48.5 51.5 - 22.6 24.4 -1-S Binary 50 - 50 71.8 72.5 -0-7 mixtures. - 50 50 22.8 25.0 -2.2 Ternary mixture ...... 33.3 33.3 33.3 29.9_ 31.9J -2.0 Coal gas ...... ... See footnote.* 30.9 28.8t $2.1 * Composition of the coal gas. C,H, etc. = 1.2 ; CO2=O.1 ; 0 ~0.1 ; C2H,=2.9 ; C0=7-3 ; H,=50-6 ; CH,=29*7 ; C,H,=3.2 ; N2=4*9 per cent. -t For the calculations the upper limits of hydrogen methane and carbon monoxide given in the table were used together with the values C,H,=4.7 (Roszkowski) ; C2H,=22.0 ; C,H,= 10.7 (Burgess and Wheeler ignition centrally in large globe. Private communication). Analyses of the residual gases showed that mixtures just below the upper limit propagated flames which consumed the whole of the oxygen and therefore passed through the ~ h d e of the mix-ture.This behaviour is in sharp cont'rast with t.hat of lower limit mixtures in which self -propagating Aames may leave unconsumed a considerable fraction of tlhe mixture. Figs. 1 2 and 3 show that bhe upper limit methane flames are characterised in contradistinction from the hydrogen and carbon monoxide flames by the possession of flame tails. Mixtures con-taining methane wit,h carbon monoxide or hydrogen and air also exhibit the m a r k a b l e tail which suggests a secondary reaction (see Fig. 4). Evidelncs as to the nature of this reaction should bs readily obtained by an examination of the intercoiial gases, c 36 PAYMAN AND WHEELER THE PROPAGATION OF but the opportunity of attempting this experiment has not pre-sented itself, C’onclzcsions (Partl IV.) . The upper limits of inflammability in air saturated with water a t 18-19O of hydrogen met>hane and carbon monoxide are in the neighbourhood of 74.2 15.4 and 74.2 per cent. respectively. The upper limits in air of mixtures of these gases taken two o’r three a t a time and also the upper limit of coal gas may be calculated with approximate accuracy by means of a simple formula of an additive character. FACULTY OF TECHNOLOGY, MANCHESTER UNIVERSITY. [Received October 12th 1918.

ISSN:0368-1645    

DOI:10.1039/CT9191500027

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

36 PAYMAN AND WHEELER THE PROPAGATION OF III.-The Pqropagation of Flarrie through Tubes of Smull Diameter. Part 11. By WILLIAM PAYMAN and RICHARD VERNON WHEELER. IT is a common practice a t collieries to test’ the safety of the miners’ flame lamps before they are taken underground by intro-ducing them into an inflammable mixture of coal-gas and air. It is known that the speed of propagation of flame in mixtures of coal-gas and air can be considerably faster than in any mixture oIf methane and air. Since any inflammable mixture into which a miner’s lamp may accidentally be introduced in the practice of coal mining is produced exclusively by firedamp and since it is a rare occurrence f o r firedamp to contain even traces of any in-flammable gas other than methane the use of mixtures of coal-gas and air for testing the security of a lamp for use underground is justifiable oaly on the grounds of providing an adequate “margin of safety.” The use of coal-gas becomes unjustifiable if the margin of safety thereby provided is excessive; for every additional pro-tective device embodied i n the construction of a miner’s flame safety-lamp militates against the proper ventilation of the lamp, and theref ore diminishes its lighbgiving power.It is thus of importance to be ablel to make an exact comparison between the speeds of propagation of flame in mixtures of coal-gas and air and fire-damp or methane and air under similar conditions of experiment. Furthermore since the rapid speed of flame in coal-gas-air mixtures is presumably due mainly to the hydrogen contained therein and since different qualities of coal-gas contai FLAME THROUGH TUBES OF SMALL DIAMETER.PART 11. 37 different proportions of hydrogen i t is necessary to obtain infoma-tion regarding the effect of varying the proportions of the con-stituent gases in coal-gas on the speed o€ propagation of flame in its mixt’ures with air. Following the same methods of experiment as with mixtures of fire-damp and air (T. 1918 113 656) the speeds of the uniform movement of flame in mixtures with air of coal-gas hydrogen and a 1 1 methane-hydrogen mixture have been determined in glass tubes of different small diameters for comparison with the results obtained with fire-damp-air mixtures in similar tubes. Compara-tive expe’riments have also been made on the projection of flame through brass tubes of small diameter.For the experiments with mixtures of coal-gas and air a supply of gas from the main was stored over alkaline water in a metal gas-holder of 70 litres capacity; and the mixtures with air were made in smaller glass gas-holders from this supply. I n this manner variations in the composihion of the coal-gas such as would have occurred had the gas for each mixture been drawn direct from the main were avoided. Rather more gas was required to complete the series of experi-ments than was anticipated so that it was found necessary t o re-charge the storage-holder before all the information desired was obtained . From one point of view this was unfortunate for the second charge of gas differed slightly in composition from the first and mixtures with air of the one could not be directly compared with mixtures with air of the other.From another point of view how-ever the enforced use of samples of coal-gas of different composi-tions was not to be regretted for there were found to be marked differences in the speeds of propagation of flame in mixtures with air of the two qualities of gas. This observation led a t once to the determination of the speeds of flame in mixtures with air of what may be termed a “synthetic coal-gas,” containing equal parts by volume of methane and hydrogen. The results obtained taken in conjunction with the known values for methane-air and hydrogen-air mixtures under the same conditions of experiment are of con-siderable theoretical interest.whilst’ they should also prove of practical value. According to Le Chatelier (“Le Carbone,” p. 266. Paris 1908), if several combustible gases are mixed together with air the follow-ing relation exists a t the lower limit$ of inflammability of the mix-ture between the limits of inflammabilit,y N and N f of each of two gases and their proportions n and n’ in the limit mixture: 7 2 p f T L f p V ’ = 1 38 PAYMAN AND WHEELER THE PROPAGATION OF Coward Carpenter and Payman have shown (this vol. p. 28) that this formula can be applied with considerable accuracy to a numbes of mixtures of gases and that it holds also a t the upper limit of inflammability. The formula implies that if a limit mixture with air of one inflammable gas is mixed in any proportion with a limit mixture with air of another inflammable gas a limit mixture results.Another way of stating the relation in an expanded form is as follows : By means of this equation the limiting percentage L for a mixture of gases can be found directly from the known limits of the individuals; a b . . . being the percentages of the individuals in the mixed inflammable gases and La Lb . . . their respective limits. The subject of the calculation of the limits of inflammability of mixed combustible gases is introduced here because a similar formula holds with remarkable accuracy (considering the nature of the phenomena under investigation) for calculating the speeds of flame in mixtures with air of a composite combustible gas like coal-gas the speeds in mixtures of the individual gases with air being known.The formula is: . . . . . (ii) a + b + . . . . . s - a/S,+b/Sb+ . . . . in which S is the speed required; a b . . . t.he percentages of the different combustible gases in the mixed gas (coal-gas for example) ; and Sa Sb . . . the corresponding speeds of flames in mixtures of the individuals with air. This formula necessarily finds its readiest application in the calculation of the speeds in distinctive mixtures namely (1) the limit mixtures upper and lower in which the speed of flame is slowest; and (2) the mixtures in which the speeds of flame are fastest. For such mixtures the agreement between calculat.ed and observed speeds is close. I n the table that follows are given (1) the limits of inflamma-bility with horizontal propagation of flame in a glass tube 9 mm.in diameter for hydrogen methane and a mixture of equal parts of hydrogen and methane; and (2) the speeds of the uniform move-ment of flame in a ho'rizontal glass tube 9 mm. in diameter with the lower- and upper-limit mixtures and in the mixtures with the fastest speeds o t flame for hydrogen methane and the 1 1 hydrogen-methane mixture. The calculated limits and speeds fo BLAME THROUGH TUBES OF SMALL DIAMETER. PART II. 39 the hydrogen-methane mixture as determined by equations (i) and (ii) respectively are also given. Speeds of uniform movement of flame. Cm. per second. I Lower-Limits. Per cent. limit Lower. Upper. mixture. Hydrogen ............ 6-7 65.7 8-3 Methane ............7.8 11.6 32.6 Hydrogen- 1- (Obs.) 7.2 19.6 13.7 methane mixture J (ca~c.) 7.2 19.7 13.2 Mixture with Upper-fastest limit speed. mixture. 430 49 96 17.1 (;;!a 90 (42) The value obtained for the speed of propagation of flame in the upper-limit mixture of hydrogen and air is iiot the true value, which should approximate t o that of the speed in the lower-limit mixture. The probable reason for the discrepancy is explained later. Omitting this value and the calculated value f o r the speed of flame in the upper-limit mixture of hydrogen-methane-air based on it it will be seen that there is a close correspondence between the calculated and the observed values for the limits and speeds. With coal-gas the gases that preponderate are hydrogen and methane which in the two samples A and B used foc these experi-ments totalled 83.5 and 85 per cent’.respectively. Ignoring the other gases calculation according to equation (ii) gives 106 and 96 an. per second respectively as the maxirnum speed obtainable during the uniform movement’ of flame in a tube 9 mm. in diameter in mixtures of each sample of coal-gas with air. The speeds as detekmined by chronographic means were 106.2 and 94 an. per second. The proportion of mixed gases to be added to air to give inixtures with thel fastest speed of the uniform movement of flame can also be calculated knowing the corresponding values for each individual gas. The fastest speed with mixtures of methane and air is obtained over the range 9*5-10*0 per cent.of methane; with mix-tures of hydrogen and air the range is 38-45 per cent. of hydrogen. Using the same type of formula as for calculating the limit mixtures the “fastest speed mixtures’’ of air with mixed combustible gases are found t o be as follows: Mixtures with air in which the speed of the uniform movement of flame is fastest. Per cent. o f combustible gas. Combustible gases. Calculated. Observed. H y drogen-methane, Coal-gas A ............... 17.5-18.8 184-19.0 Coal-gas H ............... 16.3-17.9 16-5-17-5 (1 1) .................. 15*2-16*3 15*0-16* 40 PAYMAN AND WHEELER THE PROPAGATION OF If equation (ii) is expressed in the form - a+b+ . . . . a/S,+b/Sb+ . . . . - -#a,+b+ . . . . * i t is a t once apparent that the inverse of the speed of flame in mixtures of a composite gas with air is a simple additive property of the inverse of the speed of flame in each constituent gas with air.I n other words the time taken for flame t o spread through a given volume of a mixt'ure of combustible gases with air under the conditions of combustion during the uniform movement is the mean of the times taken for flame t o spread through the same FIG. 1. j I Combustible gas in air. Per cent. volume of mixtures of each constituent gas with air if present alone. No doubt this relatioln which has been shown to hold true for the fastest and the slowest speeds of the uniform movement of flame is true also as suggested by the generalisation just stated, for intermediate speeds. So that given the necessary data respect-ing the individual combustible gases the behaviour of flame in any mixture of seve'ral with air can be deduced.The exposition of the validity or otherwise of this assumption when three or more combustible gases in varying proportions are used will form the subject of a subsequent communication. I n Fig. 1 are shown plotted to the same scale the speed-per FLAME THROUGH TUBES OF SMALL DIAMETER. PART 11. 41 centage curves for the uniform movement' of flame in a horizontal glass tube 9 mm. in diameter for hydrogen and methane for a 1 :1 mixture of hydrogen and methane and f o r coal-gas (sample A ) . The curve for hydrogen is constructed from Haward and Otagawa's determinations (T. 1916 109 SS) with additional figures obtained near and a t th0 limiting percentages.I n this connexion it should be noted that Eaward and Otagawa though they made no attempt to determine accurately the limits of ill-flammability f o r horizontal propagation of flame considered that in a tubs 9 nun. in diameter flame would not travel horizontally in mixtures containing less than 11.8 or more than 63.5 per cent. of hydrogen. Actually the 1imit.s under the conditions thus specified are 6.7 (lower) and 65.7 (upper) per cent. It was found that when igniting mixtures near the limits of inflammability, great care had to be exercised to avoid disturbance a t the mouth of the tabe and for that reason a lighted taper such as was employed by Haward and Otagawa which answered admirably over the range of mixtures studied by them was unsuitable.* * The details of the determinations made to locate the limits of inflam-mability of hydrogen-air mixtures in a horizontal tube 9 mm.in diameter are as follow the tube was 1.5 metres long and the mixtures were ignited by a secondary discharge across a 5 111111. gap 4 cm. from the open end of the tube. Lower limit. Hydrogen per cent. Result. 9.4 Flame travelled throughout. 7.5 Y Y I9 ?, 7-1 99 Y 9 , 6.8 9 9 97 ,? 6.6 Incomplete propagation of flame. These results place the lower limit at 6-7 per cent. hydrogen. A mixture of this composition when tested failed three times to propagate flame but on five occasions flame travelled throughout the length of the tube. The flames travelled very slowly and were only visible when the room was in complete deskness.Upper limit, Hydrogen per cent. Result. 63.5 Rapidly moving flame throughout. 64.5 9 9 9 9 ?? 65.0 I # ?? Y 9 65.3 9 9 9 97 With mixtures containing 66 per cent. or more of hydrogen a sharp report occurred on sparking due to the rapid combustion of a mixture made poorer in hydrogen by diffusion between the point of ignition and the open end of the tube. Flame also travelled rapidly over short distances towards the closed end of the tube; thus with 67.5 per cent. hydrogen the flame travelled 25 cm. and with 67.8 per cent. 10 cm. With 68 per cent. no flame could be C 42 PAYMAN AND WHEELER THX PROPAGATION OF Attention should be directed to the slow speed 8.3 cm. per second a t which flame could travel in a mixture of hydrogen and air a t the lower limit a fact which illustrates the well-known persistence of hydrogen flames.I n conformity with the results obtained f o r other gases it was expected that the flame in the higher-limit mixture would be equally slow. The fact that so high a speed as 50 cm. per second was recorded was due to the difficulty experienced in igniting the mixture before diffusion a t the mouth of the tube could decrease the percentage of hydrogen there. The coal-gas was made a t the carbonising plant- of the Experi-mental Station and was not diluted with water-gas. The analyses of the two samples were: Sample A. Per cent. I3enzene and higher olefines ......... 1.2 Carbon dioxide ........................... 0.1 Carbon monoxide ........................ 7 . 3 Hydrogen .................................50.6 Methane and higher parafins ...... 32.9 Nitrogen (by difference) ............... 5.0 Ethylene ................................. 2.9 Sample B. Per cent. 1.6 nil 2.8 7- 1 47.0 38.0 3.5 It will be seen that the difference between the two samples of gas lay almost entirely in the proportions of hydrogen and paraffins that they contained; and from a comparison between the speed-percentage curves for coal-gas A and the hydrogen-methane mixture given in Fig. 1 it is evident that the slower speed of flame obt,ained with coal-gas B as compared with coal-gas A is due to t.he higher methane-content of the former. For the highest speed obtainable with the hydrogen-methane mix-ture which contained 50 per cent.of each constituent is consider-ably slower than the highest? speed obtainable with coal-gas A , which also contained 50 per cent. of hydroger but only 33 per cent. of methane. The results obtained on the propagation of flame in horizontal glass tubes of smaller internal diameter than 9 mni. are recorded in the tables that follow. The determinations were made in the same manner and the numbers in the table have the same signifi-cance as in the experiments with mebhane and air (Zoc. cit. p. 658), with which they should be compared. observed t o travel away from the open end of the tube. These results place the upper limit for self-propagation of flame between 05.3 and 66.0 per cent. hydrogen. The determination was completed as follows : Hydrogen per cent.Result. 65.9 65.7 ¶ * 3 9 65.6 Flame travelled rapidly about 40 cm. Complete propagation of ff ame. 9 FLAME THROUGH TUBES OF SMALL DIAMETER. PART 11. 43 Internal diameter of tube, nun. 2.0 3.0 4.2 5.0 6.0 7.1 8.0 Internal diameter of tube, mm. 2.0 3.0 4.2 5.0 6.0 7.1 8.0 Internal diameter of tube, 111111. 8-45 2-0 nil 3-0 -4.2 -5.0 -7.1 (30) 8.0 (40) TABLE I. Coal-gas Sample A . Coal-gas in mixture. Per cent. - 13.1 16.4 17-5 18.4 19.2 20.0 22.7 24.5 nil nil nil nil nil nil nil nil (50) - - 81.3 - - nil* -49.6 - - 87.3 - - nil* -35.3 - 53.5 - -55.5 - - 99.1 - - 40.6 nil* 58.7 86.8 97.7 103.7 102.7 90.3 50.6 nil* 98.1 - -59.2 87.4 98.8 t104.2 103.9 91.8 57.0 29.8 7 9.45 nil nil 38.7 39.4 -(28) TABLE 11.Coal-gas Sample B. Cod-gas in mixture. Per cent. 13.1 14.0 14.8 16.5 16.8 nil nil nil nil nil 60 nil (35) (35) (41) (52) (57) - - -- - - -- - - - - - - -62.2 71.4 84.1 80.1 63-2 77-4 85.8 82.3 TABLE 111. Bydrogen-Hethane 1 1, Hydrogen-methane in mixture. Per cent. A v 11.90 13.90 14-35 14.95 15-95 17.20 18.10 18.65 19.55 nil nil nil nil nil nil nil nil nil 56.3 74.9 - 74.5 73.0 nil* - - -57-9 75.9 - - - 46.1 nil* - -59.4 83.1 - 86.0 84.0 53.5 nil" - -63.0 85.1 88.0 95.8 94.1 74.1 43.3 nil* -69.5 87.1 90.7 - - 75.8 49.4 34.2 nil* * Flme travelled towards the open ends of the tubes a distance of 3 cm. The results recorded in table 111 are shown as smoothed curves in Fig. 2 which illustrates the extent to which the "limits" are dependent on the environment of the inflammable mixtare.It will be seen that the range of mixtures over which continued (hori-zontal) propagation of flame was possible became gradually restricted as the diametesr of the tube was decreased until with a c" 44 PROPAGATION OF FLAME THROUGH TUBES OF SMALL DIAMETER. 3 mm. tube it was less than half of that obtaining in a 9 mm. tube. With a tube 2 mm. in diameter no flame could travel away from the point of ignition whatever the percentage of combustible gas present an observation that applies also to the mixtures of coal-gas and air. With all mixtures of methane and air a diameter of 3.6 mm. prevented tGhe propagatdon of flame; whereas with hydrogen and air (30 per cent.hydrogen) Mallard and Le Chatelier (Ann. des Mines 1883 [viii] 4 320) have recorded’ the propagation of flame in a glass tube only 0-9 mm. in diameter. Complementary to these results are the results of experiments loor-401. 1 8 FIG. 2. I -T 0 12 Combustible gas in air. Per cent. made on the passage of flame in mixtures of coal-gas and air through brass tubes either open at’ both ends or arranged as extensions to a larger vessel a t the closed end of which the mix-ture was ignited. It is unneceesary t o give the debails of these experiments which were conducted in the1 same manner and ex-hibited the same general features as the experiments with methane. It is sufficient to record that the flame in an 18 per cent. mixture of coal-gas B and air passed through 15-18 crn.length of brass tube of 4.4 mm. internal diameter placed horizontally and open a t both ends and was projected from a closed veesel (20 cm. long) through 13-15 cm. length of the same brass tubing. The corre MIXTURES OF NITROGEN PEROXIDE AND NITRIC ACID. 45 sponding distances when a 10 per cent. mixture of methane a d air was used were 7.5 and 3-4 cm. respectively. The general conclusion to be drawn from these experiments as regards the testing of miners’ safety-lamps is that coal-gas ” is an unsuitable gas t o employ for that purpose for the following reasons : (1) Comparatively small variations in the composition of coal-gas affect! the speed a t which flame can travel in its mixtures with air. I n particular a reduction in the proportion of paraffins which it contains such as is usually accompanied by an increase in the proportion of hydrogen when as generally carburetted water-gas is employed to dilute the coal-gas enables a much higher speed of flame to be attained than can be given by mixtures of methane and air. (2) Even with gas produceld solely by the carbonisation of coal a t normal retort temperatures the speed of propagation of flame attainable is more than double that possible in mixtures of methane and air. (3) It would seem that the ability of flame to pass through tubes or holes of small diameter is not dependent alone on its speed, although this is the main factor but is t o a certain extent a quality of the inflammable gas concerned. Flame in mixtures of hydrogen and air possesses the property of being able to pass through holes of very small diameter and the presence of hydrogen in coal-gas confers this property in a certain degree on the flame in mixtures of the latter with air. ESKMEALS , CUMBERLAND. [Received October 30th 1918.

ISSN:0368-1645    

DOI:10.1039/CT9191500036

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

MIXTURES OF NITROGEN PEROXIDE AND NITRIC ACID. 45 I1 I.-Mixtures of hTitYogen Peroxide and Nitric Acid. By WILLIAM ROBERT BOUSFIELD K.C. NITRIC acid and nitrogen peroxide' are mutually soluble in certain proportions and in other proportions give rise to a double layer. When t o the simple binary mixture1 water i s added a more com-plex mixture arises. A systematic study of these mixtures was projected beginning with the simple binary lrixture and passing on t o consider bhe modifications which are introduced by the addi-tion of water. The present' communication deals with the firs 46 BOUSFIELD MIXTURES OF part only of this research. The nitric acid and nitrogen peroxide for the research have been specially prepared by Nobel’s Explosives Co. LM. with whase chief research chemist, Mr.Rintoal I have been in consultation from time to time. Nitrogen Peroxide .-Nitrogen peroxide absorbs moisture readily, and in the absence of excess of nitric acid appears to decompose according to the equation N,O + H20 = HNO + HNO,. The presence of a very small quantity of water will therefore cbange the colour of liquid nitrogen peroxide to a dirty green but traces of moisture may involve the presence of nitrogen trioxide without noticeable change of colour. Two samples of liquid nitrogen peroxide were supplied by Messrs. Nobel. Nearly all the work was donel with sample No. 1 which was subsequently found to have contained traces of nitrogen trioxide. Sample No. 2 had been purified by distilling i t with phosphoric oxide. The prob-able reactions which result in this purification appear t o be 2HN0 + P205 = 2HP0 + N205, N,O,+ N20,=2N,O,.This sample No. 2 may be regarded as pure’ liquid nitrogen peroxide. I n the meantime before receiving this pure sample I had used up sample Not. 1 in nitric acid solutions and recovered it by dis-tillation and rectification with a pear still-head. This sample to which I may refer as No. 3 appears by the density given below to be nearly as pure as No. 2. This is probably due to the oxida-tion of the nitrogen trioxide by nitric acid according to the equation ZHNO + N,O = 2N,O + H,O. Thus with excess of nitric acid and very little water the reaction N20 + H,O = HNO + HNO, appears to be reversed and in the presence of excess of nitric acid the water appears to have no decomposing effect on t.he nitrogen peroxide.As further evidence of t.his the addition of a few drops of water to the orangecoloured liquid nitrogen peroxide turns itt a dirty dark green presumably due to the mixture of the blue nitrogen trioxide or nitrous acid with the1 orange nitrogen peroxide but t3he addition of a few drops of nitric acid destroys the green and restores the orange colour. Thee green d o u r cannot be eliminated by simple rectification, as the nitrogen trioxide and peroxide appear to pass off together, the resulting gas being of a somewhat deeper red colour than that of pure nitrogen peroxide. Nor does the addition of syrupy phm NITROGEN PEROXIDE AND NITRIC ACID. 47 phoric acid help matters. Solid phosphoric oxide appears to be necessary to get rid of the nitrogen trioxide unless excess of nitric acid is added.Another sample (No. 4) of a bulk of about half a litre which had been accidentally contaniinated with sufficient water to turn i t to the dark green colour was mixed with sufficient nitric acid to restore hhe orange colour and then distilled with phosphoric oxide. The resulting sample No. 5 was of the same colour and density as the pure sample No. 2. I n t.he rectification of sample No. 4 the first few C.C. passed over green a t a temperature at4 the top of the still-head of 19-20'. The bulk which constitutes sample No. 5 distilled a t 21-9-t0*lo which may be taken as the boiling point of pure liquid nitrogen peroxide. TABLE I. Specific Volu~i7 es o f Samples o,f YitrogetL Peroxide.NO. 1 ............ 0.67390 0.68110 0-68864 NO. 2 ............ 0.67435 0.68172 0.68938 NO. 3 ............ 0.67432 0.68168 0.68935 No. 4 ............ - - 0.68946 No. 5 -4". 11". 18". - 0.68170 ............ A set of density observations on sample No. 1 was taken a t the temperatures given in table 11 which gives the observed specific volumes and those calculated from the formula 2r = 0.66994 + 0.0009767t + 0.00000344t2. TABLE 11. Specific Volumes of Sanzple N o . 1 at Various Tenbperatures. t. D. v observed. v calculated. Difference. 0.08" 1.49250 0.67002 0.67002 i 11 1.46822 0.68110 0.681 10 rt 15 1.45909 0.68536 0.68536 rrt 20 1.44750 0.69085 0.69085 A 7 1.47704 0.66703 0.67695 - 8 18 1.45214 0.68864 0.68863 - 1 For the pure sample No.2 the specific vo81ume-tempesature curve derived from the three duplicated observations a t 4O 1l0, and 1 8 O is which may be taken as giving the correct specific volume of pure nitrogen peroxide a t temperatures from Oo to 20° within + 2 in the fifth place of decimals = 0.67027 + 0.00100'75t 4- 0.000003t2 48 BOUSFIELD MIXTURES OF iVitm'c Acid.-The nitric acid used was specially purified and sent to me by Messrs. Nobel with the' following analysis: Nitric acid ........................ 99.68 per cent. Hydrochloric acid ............... 0-007 , ,, Sulphuric acid .................. 0.068 .... Nitrous acid ........................ 0.012 , .. Mineral matter .................. nil 99.767 , ,, I have taken the percentage of water by difference as 0.233 per The densities of this acid a t the temperatures indicated are: cent.4O. 1 1 O . 1 so. 1.5381 1.5254 1.5126 I n calculatdng the strength of the various mixtures of nitric acid and nitrogen peroxide, to which reference1 is made later the nitrous acid given in the above analysis has been reckoned as nitrogen peroxide since for the reasons above given it is assumed that with very concentrated nitric acid the nitrous acid present is oxidised to give nitrogen peroxide and water. In tab10 I11 are given the resulting values of the specific volumes derived from the density determinations.* P is the per-centage by weight of nitrogen peroxide in the mixture. The temperature coefficients a from 4O to 1l0 and from 1l0 to 1 8 O TABLE 111. Specific Volumes o:f Mixtures uf ATitric A ck? an,d Nitrogen Peroxide.P. 0 1,2168 8.021 16.88 26-09 34.925 37-60 42.01 43.71 46.70 48.66 49.96 51.37 53-10 93-86 96-93 98.49 100~00 v4. 0.65015 0.64839 0.63719 0.62372 0.6121 4 0.60445 0.60296 0.601 12 0.60082 0.60088 0.60113 0.60145 0.60205 0-60341 0-67305 0-67371 0.67435 I 2'11. 0.65557 0.65374 0.64211 0.62821 0-6 1655 0.60885 0-60743 0.60568 0.60543 0.60561 0-60599 0.60639 0.607 15 0.60873 0.68030 0;68098 0.68172 -V18* 0.661 13 0.65920 0.64715 0.63291 0.82113 0-6 1346 0.6 1204 0.6 1044 0.61026 0-61059 0.61110 0.61161 0.61248 0-61436 0.68610 0.68786 0.68855 0.68938 Temperature-coefficients. A r -.4-11' 11-18O x 105. u x 106. 77 79 76 78 70 72 64 67 63 65 63 66 64 66 68 68 66 69 68 71 69 73 71 75 73 76 76 80 104 108 104 108 105 109 - -* The actual density determinations have been omitted at the request of the Publication Committee to save space NITROGEN PEROXIDE AND NITRIC ACID. 49 TABLE IV. Coiztraction of Mixtures of Xitric Acid and Nitrogen Yerolxide. Contraction per C.C. of solution. Contraction per gram of solution. P. 1.22 8.02 16-88 26.09 34-92 37-60 42-01 43-7 1 46.70 48.66 49.96 51-37 53-10 93.86 96-93 98.49 4". 0.0032 0.0234 0.0489 0.0724 0.0896 0.0934 0.0985 0.0997 0.1008 0.1011 0.1011 0.1005 0.0988 0.0008 0.0004 -11". 0.0033 0.0242 0.0506 0.0743 0.0917 0.0954 0.1005 0-1017 0.1027 0.102s 0.1026 0.1019 0.0998 0.0009 0.0005 -IS&.0.0034 0.025 1 0-052 1 0.0763 0.0938 0.0976 0.1025 0.1036 0.1044 0.1044 0.1040 0.1031 0-1005 0.0023 0.0009 0.0006 4 O . 0.002 1 0.0149 0.0305 0.0443 0.0542 0.0563 0.0592 0.0599 0.0606 0.0608 0.0608 0-0605 0.0596 ---1 1 O . 0.0022 0.0156 0.0318 0.0458 0-0559 0.0580 0.0609 0.0616 0.0622 0.0623 0.0622 0.0619 0.0607 ---18" 0.0023 0-0163 0.0330 0.0474 0.0575 0-0597 0-0626 0-0632 0.0637 0.0638 0.0636 0.0632 0.0618 ---are also set out in table 111 as they give an important clue to the nature of the combination which is taking place1 in the mixture.Another important matter bearing on this is the contraction which takes place a t various constitutions of the mixture. The euthetic point that is t,he point of closest packing (see Bousfield, T. 1915 107 1412) may be obtained by calculating ths ratio of the volume of the constituents before mixture t'o the volume a t the same temperature after mixture which is where v,- = specific volume of nitrogen peroxide w = specific volume of nitric acid v =specific volume of the mixture. It should be noted that R-1 is the contraction per C.C. of solu-tion formed tho values of which are set out in table IV. I n the same table are set out the values of the difference between the volume of a gram of the constituents before mixing and the volume after mixing which is Pv,+(lOO -P)w ~- - v.A = 100 Consideration. of t t e Results.-The results given in the tables are exhibited in Figs. 1 2; 3 and 4 where they are set out on the values of P the percentage by weight of nitrogen peroxide as abscissae. There are shown i n 50 BOUYEIELD MIXTURES OF Fig. 1 the specific volumes of the mixtures. Fig. 2 the values of 22 - 1 near the maximum. Fig. 3 the valueis of h near the maximum. Fig. 4 the temperature coefficients for the intervals 4-11° aiid 11-18°. FIG. 1. 90 100 0.66 0.65 0-64 0.63 0.63 0.61 0.60 0.63 0.67 0 10 20 40 50 60 Specific volume of mixtures of nitric mid and nitrogen :c =Percentage of nitrogen peroxide. y = Speci$c volume. 4 O 11° and 18O. peroxide ut The notab16 heat of evolution on mixing approximately equal weights of nitric acid and nitrogen peroxide (which it.is proposed to determine accurately a t a later st'age) indicates a powerful com-bination. The minimum values of the specific volume curves give the same indication showing a notable contraction of about 1 NiTROGEN PEROXIDE AND NITRIC ACID. 51 The minima do not however locate the exact. composi- per cent. tion. They occur : for for 1 8 O , 43.8 ,, 4O a t about 44.6 per cent. for 11° , 44.2 ) ) F I G . 2. 0.104 0.103 0.102 0.101 0.100 0.099 0.098 40 50 Contraction per C.C. of solution. x = P . y = R - 1 52 BOUSFIELD MIXTURES OF The position of the minimum is so largely determined by the mere density differences of the two components that it cannot' locate precisely the percentage of the combination.The euthetic point (see Bousfield Zoc. c i t . ) is generally very close to the neighbourhood of the point of definite composition. The FIG. 3. I 55 Contraction per grain of solution. x=P. y = A. values of the contraction per C.C. of solution which determine the euthet,ic point are given in table IV and set out in Fig. 2. The maxima correspond with the euthetic point and occur: for for 1l0 ,? 48.4 >, for 1 8 O ? 47.6 ,, 4O a t about 49-2 per cent NITROGEN PEROXIDE AND NITRIC ACID. 53 The actual position of the euthetic point is determined not only by contraction due t o combination but also by contraction due to changes in the polymerisation of the constituents. The high temperature coefficients for both constituents indicate that these changes are notable.The percentage 49.2 a t 4 O corresponds very nearly with the composition 3HN0,,2N2O4. If we! take the curves in Fig. 3 in which the values of the con-traction per gram of solution are set out the effect of polymerisa-tion is ts some extent excluded and the maxima f o r 4O and 1.l0 appear to occur a t 49.3 per celnt. whilst that for 1 8 O is again shifted slightly to the left. On the' whole then itq may be said FIG. 4. 80 70 60 0 25 50 Temn~~crature-coe~cients of specific volums of mixtures of nitric acid and nitrogen peroxide. x = P . y = Temperature-coe$icient a. that the indications point to the composition of the definite com-pound 3HN03,2N,04 which co'rresponds with 49.33 per cent.An inspection of Fig. 4 in which the temperatxre coefficients are set out shows a definite minimum at. 26.7 per cent. which appears to be the same for each range of temperature; this corre-sponds with the definite composition 4HN0,,N20,. The first part of the specific volume curve shown in Fig. P is approximately straight' which indicates that the wholel of the nitrogen peroxide added up tto about 15 per cent'. enters into this combination with nitric acid. Furthermore the proportions of nitric acid and the compound 4HNO3,N,O4 derived from the mass-act& relation give a calculated specific volume which corresponds closely wit 54 MIXTURES OF NITROGEN PEROXIDE AND NITRIC ACID. the actual specific volume curve for a considerable distance that is until the e'ffect of the increasing proportion of the still denser cmbination becomes sensible.On the whole we may conclude that a t least two definite compounds exist in the solutions namely, 4HN03,N,04 and 3HN0,,2N,04. The Composition of t h e Double Layers.-The specific volume curves have a gap bet'ween about 54 and 92 per cent. If at 4-18O a mixture between these limits is made the solution separates into t8wo layers which are mutually saturated. Nitrogen peroxide is soluble in nitric acid up to about a 54 per cent. solution but the solubility of nitric acid in nitrogen peroxide is very much less. I n order to determine the maximum solubili-ties a t different' temperatares the two components were shaken together from Cime to time a t the required temperatures forming a cloudy liquid and kept in a thermostat until the two clear layers were completely separated.The different layers were then drawn off into a pyknmeter a t the required temperatures and again kept in the thermostat a t these temperatures during the adjustment of the pyknometer. The resulting deasity determinations enabled the compositions to be determined. I n table V are given the density observations for saturated solutions of nitric acid in nitrogen peroxide together with the specific volumes a t the temperatures and the resulting percentage, p of nitric acid in the saturated solutions. TABLE V. Saturated Solutions of Aritric d cid in Nitrogen Peroxide. Percentage of D. V. nitric acid. 4 O 1-48742 0.67231 4.90 11 1.47351 0.67865 6.67 18 1 - 459 40 0.68521 8.05 Since at this end of the specific volume curves they are practic-ally straight lines the percentages are easily calculated from the f armula where vo =specific volume of nitrogen peroxide vt =specific volume of solution containing p per cent.of nitric acid the values of the constants being : uo - vt = Bp, 4O. 1 1 O . 18". 0 0 0.67435 0.68172 0.68938 B 0*000424 0.000476 0.00052 6 It will be observed that the solubility of nitric acid in nitrogen peroxide rises rapidly with temperature being about doubled i EFFECT OF DILUTION IX ETJECTRO-TITRIMETRIC ANALYSES. 55 the range from Oo t o 20°. The values indicate that the solubility would vanish a t about -loo. In table VI are given the density observations for saturated solutions of nitrogen peroxide in nitric acid together with the specific volume a t the temperatures and the approximate per-centages of nitrogen peroxide' in the saturated solutions. TABLE VI. Sktiwuted Solutions of Nitrogen Peroxide iit A'itric Acid. 4 O 1.65432 0.60448 54.4 11 1.63942 0-60997 54-3 18 1.62501 0.61 538 54.0 D. V . P. I n t.his case the approximate compositions are determined diagrammatically from a large-scale specific volumel curve. The temperature of my laboratory in the end of May when these last observations were taken made them very difficult. It is however, clear that the change of solubility with te,mperat,ure is in this case very small and i t appears t o diminish with rising temperature. ST. SWITHIN'S, HENDON N.W. [Receiwed August 29th 1918.

ISSN:0368-1645    

DOI:10.1039/CT9191500045

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

EFFECT OF DILUTION IX ETAECTRO-TITRIMETRIC ANALYSES. 55 IT V. -The Efect qf Dilution in Blectro-titmhetric Analyses. By GILBERT ARTHUR FREAK. THE first application of conductivity measurements to analysis is that due to Kiister and Griiters (Zeitsch. anorg. Chem. 1903 35, 454) who showed that acids could be titrated accurately by these means. Later Kiister Griiters and Geibel (ibid. 1904 42 225) proved the accuracy of the method even when such substances as potassium dichromate and potassium permanganate were present in the acid solution. The estimation of acetic acid in vinegar of total acid in red wine of magnesia and o,f various alkaloids was also shown to be possible. Further work has demonstrated that the method is capable of very varied application. Amongst the uses to which i t has been put may be noticed the analysis of wines by Duboux (C'hem.Zed., 1913 37 879) and by Duboux and Dutoit (Compt. rend. 1908 56 FREAK THE EFFECT OF DILUTION IN 147 134) the preparation of neutral ammonium citrate solutions by Hall (J. Ind. Eng. Chem. 1911 3 559) and the analysis of soil solutions by Van Suchtelen and Itano (52nd ,4nn. Rep. Mich. B w d of ,4gm'c. 1913 49). The lastlnamed workers have also pub-lished ( J . Amer. C'hem. SOC. 1914 36 1793) the results of experi-ments on the estimation of chlorides sulphates nitrates phosphates, potassium calcium ferrous iron strong and weak acids and of chlorides and phosphates in urine. Quite recently Harned ( J . Amer. Chem. SOC. 1917 39 252) has shown that certain bivalent metals in the form of their sulphates can be determined accurately by the conductivity method by ticration with barium hydroxide.Meerburg (Versl. w. h. Centr. Lab. t. b . h. v. h. Staatsoez. 0. d. Vdksgehondh. 44-54 1917 ; Chern. TT/'eel;blad 1917 14 1054) has reported adversely on the method as applied t o the estimation of sulphates by barium acetate and of calcium by oxalic acid but mentions that good results may be obtained in the determination of alkalinity in potable waters. It is noteworthy that although the method has been applied to SO many reactions no attention has been paid to the1 lower limit of concentration at which accuracy may still be obtained. Most of the experiments have been carried out on relatively concentrated solutions (seldom weaker than O-llV) the only reference to results with very dilute solutions being one by Van Suchtelen and Itano (loc.cit.) who state that the titration of as little' as 5 C.C. of 0.001N-sulphuric acid with O.OIAT-sodium hydroxide can be per-formed accurately. I n those titrations involving the precipitation of a salt the solubility of which would be expected to limit the sensitiveness of the method this p i n t has not been touched upon, It appears therefore to the author that an investigation of this nature was desirable. If the method is capable of yielding accurate results a t very low concentrations many estimations f o r example, those carried out in the analysis of potable waters could be made without previous concentration of the solutions. The present com-munication is concerned with the limits of the method as applied to the estimation of sulphates chlorides calcium and magnesium.Rigid accuracy was not aimed at the object being t o find t o what extent the method could compete with ordinary gravimetric or volumetric processes without the introduction of troublesome pre-cautions. To that end beyond the use of standardised measuring vessels and of " purest " commercial reagents no special precautions were taken. No attempt was made to keep the temperature of the s0l;utions constant during the titrations the duration of which was usually fifteen t o twenty minutes ELECTRO-TITRIMETRIC ANALYSES. 57 F x P E I M E N T A L. Except f o r the use of a double receiver telephone which proved very convenient i n minimising the interference of external noises, the apparatus employed was of the usual nature and therefore calls for no special comment.The liquid t o be1 titrated was placed in a beaker of such a size that thorough mixing could be effected by giving the vessel a rotatory motion the stationary electrodes serving as a stirrer. The reagent was ddivere'd from a burette capable of being read to 0.01 C.C. The curves were plotted with conductivity as ordinates and volume FIG. 1. 0.024 0.023 0.016 0.01 4 C.C. N/10-BaCI2. of reagent as abscissz and in order to eliminate experimental errors a t least three and usually more readings were taken on each limb' of the curve. Estimation of Sulpha tes. A stock solution of Xerck's purest potassium sulphate was pre-pared and the SO estimated gravimetrically in duplicate as barium sulpliate.From this solution weaker solutions were prepared by dilution. For the titration of these two solutions of barium chloride approximately IT/ 10 and iV/ 25 respectively were prepared and silrilarly standardised. Table I shows that the results are accurate only down to a con-centration of about 200 milligrams of SO per litre a typical curve being shown in Fig. 1. When the concentration of SO is 100 milli 58 FREAK T’HE EFFECT OF DILUTION IN grams o r less per litre tlie precipitation of barium sulphate is so incomplete that the resulting curve changes entirely in character, exhibiting irregularity but no definite break such as appears in Fig. 1. Van Suchtelen and Itano (loc. cif.) added to their solutions a certain amount of the salt that was to be precipitated with the object of avoiding errors due to solubility.I n order t o test this procedure a suspension of fine precipitated barium sulphate in dis-tilled water was added to the sulphate solution in the beaker some little time prior to titration. The results are given in Table 11. TABLE I. Concsntration of SO, Strength of so found. mg. per litre. BaCl,. Per cent. 990 N/10 100.0 100.4. 99.4 198 99 49.5 Y Y 99.2; 99.2 .99-2 N,%5 -l f No end-point. TABLE 11. Concentration of SO, Strength of SO found. mg. per litre. BaCl,. Per cent. 99 N/10 99-7 99.7 49.5 24.7 9.9 N j25 99.5; 99.2 99-6 ” } End-point indefinito. Reference to table I1 will show that this method succeeded to a certain extent as by means of it good results were obtained down t o a concentration of about 50 milligrams of $0 per litre.How-ever it was not effective when only 25 milligrams of SO per litre were present giving curves with an indefinite end-point of tlie type shown in Fig. 2. Titratioii a t boiling temperature did not alter the character of this curve. I n such cases it is possible by taking only those points well remote from the curved portion to arrive a t an approximate value for the end-point (see dotted lines). For instance, figures derived in this manner from experiments on solutions containing 25 milligrams of SO per litre were about 5 per cent. in excess of the correct value. Estimation of Chlorides. The salt chosen for this purpose was a sample ob Merck’s purest fused sodium chloride.A stock solution of this together with the approximately N / 10- and N j 25-silver nitrate solutions used for titration was standardised by duplicate gravimetric estimations as silver chloride BLECTRO-TITRIMETRIC ANALYSES. 59 The results obtained with varying concentration of chlorine are shown in table 111. TABLE 111. Concentration of C1 Strength of C1 found. mg. per litre. AgNO,. Per cent. 1000 N/10 99-7 99.3 200 100.1 99.3 100.8 50 N725 100.2 100.9 10 7 100.6 100-8 5 Y End-point indefinite. As in the case of sulphates a limit of concentration is reached a t wbich the method fails the figure in this instance being 10 milli-FIG. 2. C.C. N/25-,EaCl2. grams cjf chlorine per litre. The addition of precipitated silver chloride before titration did not render the end-point sharp a t lower concentrations.The type of curve obtained in this estimation is similar to that shown in Fig. 1. Estimation of Calcium. A stock solution of calcium chloride was prepared by dissolving pure calcite in hydrochloric acid and eliminating the excess of acid by repeated evaporations on the water-bath. Both this solution and the approximately N J 10-ammonium oxalate solution employe 60 EFFECT OF DILUTION IN ELECTRO-TITRIMETRIC ANALYSES. in the titrations were staridardised by means of potassium pennan-ganate. Table IV shows the results obtained. TABLE IV. Concentration of Ca Ca found. mg. per litrc. Per cent. 500 100.0 100.4 99.2 100.4 200 99.1 100-6 99.1 100 End-point indefinite.As in the case of the determination of chlorides previous addi-tion of the precipitated salt dirt not lead to sharp end-points a t the last-mentioned concentr8tion. I n three such experiments figures given by producing the straight portions of the curves gave 97.0, 97.6 and 95.8 per cent. respectively of the amounts taken. 3 s tinta tioia of Magnesium. A solution of Merck’s purest magnesium sulphate was employed, standardisation being effected by duplicate estimations as mag-nesium pyrophosphate. An appro,ximately N / 10-sodium hydroxide solution standardised by means of sulphuric acid and pure sodium carbonate was used f o r titration. Variation of the concentration of magnesium gave results shown in table V. The typical curves for these cases have no minimum, but exhibit a definite greak.TABLE V. Concentration of Mg Mg. found. mg. per litre. Per cent. 639 99.2 99.7 99.7 269.5 99.7 100.1 100’4 100.1 202 100.8 99.9 100-8 100.6 134.5 End-point indefinite. Addition of magnesium hydroxide prior to titration lead to no improvement a t the last-mentioned concentration. I n connexion with the estimation of magnesium by this method i t is interesting t o note that Harned (Zoc. c i t . ) says “This titra-tion gives only a fairly easily detectable end-point for the change in direction of the plot before and after the end-pint is not great. A reagent must therefore be sought which will increase; the difference in the slopes a t the end-pint.” For this reason he employed barium ’hydroxide t o titrate solutions containing magnesium sul-phate.Apart from the fact that the use of this reagent t o b THE OPTICALbY ACTIVE NEOMETHYLHYDRINDAMINES. 61 effective demands that the magnesium shall be present as sulphate and the b t a l elimination of carbon dioxide from the solution com-parison of Harned’s figures with those recorded above shows that the use of barium hydroxide does not present any definite advan-tage. It appears that errors from other sources are of greater magnitude than that derived from difficulty in reading the inter-section of the two limbs of the curve. Su?n,nnnry of Results. (1) The determination by means of conductivity measurements, of sulphates chlorides calcium and magnesium has been studied a t low concentrations. (2) It has been shown that in relatively weak solutions very small quantities of each of the above1 mentioned may be estimated, withoat any attempt a t temperature control with an error not exceeding + I per cent. (3) In each case a limit of dilution is reached a t which the results cease t o be accurate smooth conductivity curves being obtained. With the exception of the1 case of sulphate estimations, saturation of the solution with the salt to be precipitated does not lead to an improvement in this respect. WELLCOME TROPICAL RESEARCH LABORATORIES, GORDON MEMORIAL COLLEGE, KHARTOUM. [Received August Cith 1918.

ISSN:0368-1645    

DOI:10.1039/CT9191500055

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

THE OPTICALbY ACTIVE NEOMETHYLHYDRINDAMINES. 61 V.-The Optically Active neo Methyl~~yd?,z'ndumines. By (the late) LT. J-OSEPH WALTER HARRIS.* THE reduction of 8-methyl-a-hydrindoxime CH2<yz$> C:NOH, with sodium amalgam and acetic acid leads to the formation of two * Lt. J. W. Harris B.Sc. was one of those who actuated by a high sense of patriotic duty joined the O.T.C. of the University College Nottingham. before there was any immediate prospect of a war and his efficiency and enthusiasm led to his promotion to the rank of colour sergeant. In the summer of 1914 he had just completed his first piece of research work and when war was declared he immediately volunteered for active service. Shortly after-wards he was given a commission in the 3rd Lincolns and went to the Western front where he was killed in action during the early part of the war.His death was a great blow to all who knew him whether in civilian or in military life ; he was a most promising chemist an ideal officer. The presen 62 HARRIS THE OPTICALLY ACTIVE dl-bases one of which may be isolated by the fractional crystal-lisation of the hydrochlorides prepared from the mixture (Kipping and Clarke T. 1903 83 913). The other base cannot be obtained, a t any rate easily in this way or by a similar treatment of the normal sulphates benzoates cinnamates or picrates but by frac-tionally crystallising the d-bromocamphorsulphonates and mechani-cally separating the obviously diff erent crystals both the dl-bases can be ultimately obtained in a state of purity (Tattersall and Kipping T.1903 83 918). As this method of separation was unsatisfactory the author of this paper a t the suggestion of Professor Kipping made some further experiments on the subject and found that the two &-bases in the crude product could be isolated in the manner described below. He then succeeded in resolving the dZ-neo-base into its optically active components both of which were obtained in a state of purity. All the four optically isomeric P-methylhydrindamines tlieref ore, have now been characterised ; the two neo-bases which form only abotlt 25 per cent. of the original mixture have very low molecular rotations cornparod with those of the other two methylhydrind-amines. Sepration of Methylhydrindamine and neoMethylhydrindamine b y means of their Hydrogen Oxalates.The aqueous solution of the mixed bases obtained by the reduc-tion of methylhydrindoxime was neutralised with finely divided oxalic acid and a further equal quantity of acid was added. This solution was then concentrated and cooled. The first fraction con-sisted of tufts of long silky needles and was nearly pure methyl-hydrindamine hydrogen oxalate. Subsequent fractions were simi-lar but the needles gradually became less well defined and when aboutl two-thirds of the total substance had been separated the deposits consisted of hard crystalline masses. The latter after several recrystallisations from water yielded tufts of needle-liks prisms which were neomethylhydrindamine 'hydrogen oxalate. Some ammonium salts separated in large transparent masses from time to time but these were easily removed by extracting the salt of the organic base with alcohol.By the above metho,d about fivesixths of the original mixture was separated into the two dl-salts the pro-paper is an account of his work which he handed to me before he went to the front and except the few lines of introduction and some immaterial alterations the matter is given in his own words.-F. S. K NEOMETHYLHY DBINDAMINES. 63 portion being about three to one rnet'liylliydrii~dttmine being present in the larger quantity. dl-~~et~~tylliydriizdamine hydrogen oxalat e , C1"H1l*NH, C,H,04,H207 crystallises froin water in which it is readily soluble in tufts of long silky needles melting a t 110-11lo. These are 'hydrated and lose water a t 70-80°; a t looo some decomposition is observed but this is not noticeable in the melting-point tube.The dehydrated salt melts at 143-145O with slight decomposition : 0.4338 lost 0.031 at 80°. H,O=7*14. The above formula requires H,O = 7.06 per cent. The benzoyl derivative of the base made in the usual way, crystallised from alcohol in needles melting a t 150° showing the base t o bme methylhydrindamine (Tattersall and Kipping Zoc. c i t . ) . dl-neoMet Jqlhydr.inda8mine hydrogen oxalnt e, C,,H,,*NH,,CzH20,,2H,O, in an impure condition crystallises iii compact masses. From water and alcohol the pure compound is obtained in tufts of neeldle-like prisms which partly liquefy a t about looo and finally melt a t 173-175*~which is the melting point of the anhydrous salt.When treated with benzoyl chloride the salt gave a benzoyl derivative, crystallising in needles and melting a t 169O wliich is the melting point of the benzoyl derivative of neomethylhydrindamine (Tatter-sall and Kipping Zoc. cit.) -% 0.4336 lost 0.0568 a t 903. 0.1454 anhydrous salt gave 0.3246 CO and 0.0834 H,O ; C = 60.8 ; H,0=13-1. The above forinula requires a loss of 13.2 per cent. H= 6.4. C,,H,,04N r'equires C = 60.8 ; H = 6.33 per cent. Resolqr t i o t i of dl-neo36etB?/l~~yc~damin,e. dl-n~Met~~tylhycn~amine Itydrogcn ozalate (20 grams) was decomposed with sodium hydroxide the base distilled in steam and the distillat? neutralised wi,th tartaric acid a further equal quan-tity of the acid being added to form the1 hydrogen salt.The solu-tion was then concentrated to a small balk allowed to cool and a crystal of pure I-neomethylhydrindamine hydrogen tartrate intro-* Since the melting point of the A-base described by Kipping and CLrke (Zoc. c i t ) was 169O it is evident that by the fractional crystallisation of the hydrochlorides of the mixed bases the salt of dZ-neomethylhydrindamine is fist isolated whereas in the case of the d-bromocamphorsulphonates the salt of dl-methylhydrindamine forms the most sparingly soluble fraction.-F. S. K 64 HARRIS THE OPTICALLY ACTIVE duced. A deposit consisting of tufts of needles separated and was collected. 'The amount of this fraction was roughly a b u t one-third of the whole. I f the1 solution was allowed t o remain too long before it was filtered the needle-like crystals became covered with white =asses.This first fraction was recrystallised from water until its melting point became constant. and consisted of Z-neomethyl-hydrindamine hydrogen tartrate (about 8 grams). The mother liquors on further concentration and seeding gave deposits of white masses obviously a mixture and melting over a wide range. The last mother liquors gave long white needles melting a t 1 6 5 O . It was however found t o be impossible t o isolate a pure compound from these mother liquors owing t o the great solubility of the salt. The whole of the mother liquor was therefore decomposed with sodium hydroxide the base distilled in steam and the distillate neutralised with hydrochloric acid. On concentrating the solutioa, long needles of dl-nesmethylliydrindamine separated but the final mother liquor was found to contain a salt which was more readily soluble in water than that of the dl-base and the solution of this salt showed dextrorotation.To obtain this dextro'rotatory base the active mother liquor was decomposeld with sodium hydroxide the base distilled in !team and the solution neutralised with d-bromocamphorsulphonic acid. The solution was conoentrated until it became turbid and allowed t o remain when a mass of needles separated. These were recrystal-lised from water until the melting point became constant at 229-230O. This substance was found to be d-neomethylhydrind-amine d'bromocamp horsulphona t e. 1-nedfe t hylhydrindarnine hydrogen tarrtra t e, Cl,Hll*NH,,C,H,O,,H,O, the salt which forms the most sparingly solible portion described above crystallises from water or alcohol' in large vitreous prisms, often growing together in leaf-like' masses.It is hydrated and when heated in a melting-point tube it partly liquefies a t about looo and finally melts a t 1 7 3 O . It is readily soluble in water less so in alcohol and practically insoluble in ethyl acetate acetone, benzene or chloroform : 0.3522 lost 0.0204 a t 100'. H,O=5*71. The above formula requires H,O=5*71 per cent. Samples dried a t looo gave in a 200 mm. tube in aqueous solution the following results : Wt. of salt. Vol. of solution. a. [aILl. [MIIJ. 0-7 11 6 gram . . . . . . . . . 26 C.C. 0.65" 11-4" 34" 0.4600 , . . . . . . . . . 9 9 0.42 11.4 3 NEOMETHYLHYDRINDAMES.65 As the molecular rotation of the tartaric acid ion in its metallic hydrogen salts is [MI1 4Z0 that of the base is [MI - 8 O . 1-neoMe t h y Zh ydrindaniine d- b romocamphorsulphmat e, C,oH,l~NH2,Cl,Hl,0Br*S03H, is moderately soluble in water and crystallises from the warm solu-tion in aggregates of needles the solution first becoming milky if the salt is not free from the optically active isomeric base. These needles are hydrated but lose all their water on exposure to the air. The freshly crystallised substance when heated in a melting-point tube partly liquefies a t about 80° and finally melts a t 214O It is mom readily soluble in alcohol than in water and easily dissolves in ethyl acetate chloroform or acetone but is insoluble in ether.The anhydrous salt was examined in aqueous solution in a 200 mm. tube. Wt. of salt. Vol. of solution. a. [.ID* [MI,. 0.5068 ......... 25 C.C. 2-32' 57.2' 262" 0-3856 9 9 1.75 57.1 261 ......... Taking the molecdar rotation of the bromocamphorsulphonic acid ion to be [MI 270° these results give a value of [MJD - 8 O ur -go for the base. 1-neoMethyZhydrindamine hydrochloride C,,H,,-NH,,HCl is much more readily soluble in water than the hydrochloride of the &base and crystallises from this solvent in long silky needles. It is very readily soluble in water or alcohol and also dissolves in ethyl acetate or chloroform but is practically insoluble1 in ether or carbon tetrachloride. When heated in a melting-point tube the substance begins to char at about 235O.The air-dried salt is anhydrous . The following results were obtained in aqueous solution in a 200 mm. tube : Wt. of salt. Vol.'of solution. a. [a]D. [ M I D . 0.5250 ............... 25 C.C. -0.130 -3.1" -5.70 0.7986 ............... 9 9 -0.23 -3.6 - 6.5 0.7754 ............... -0.21 -33.4 - 6.2 9 s l-neoMe t hylhydrindamine d-camphmsulphonate, C,oH,,-NH2,C,,H,SOe sop, is very readily soluble in water and crystallises in long vitreous prisms. The air-dried salt is anhydrous and when heated sinters at about 210° and finally melts a t 2 2 0 O . It is readily soluble in chloroform sparingly so in alcohol or acetone and practically insoluble in ether or ethyl acetate. VOL. cxv. 66 THE OPTICALLY ACTIVE NEOMETHYLHYDRINDAMINES. The following results were obtained in aqueous solution in a 200 rnm.tube: Wt. of salt. Vol. of solvent. a. I a]". 0.5898 ............... 25 C.C. 0.54" 11.4' 43.2' 04282 Y Y 0.50 11.8 44.7 Taking [MI for camphorsulphonic acid as 49O these results give for the base [MI - 5 ' 8 O and -4.3O respectively. The bemoyi derivative of I-meornethylhydrindamine crystallises from aqueous alcohol in long silky needles melting a t 171O. d-neoMethylh,,?/dmndamine d-bromocamphJorsulphonate, ............... CloHll*NHz,C,,H,,OBr*SO,H, is readily obtained in a pure condition from the active base con-tained in the mother liquors from the dl-hydrochloride (see above). It crystallises from warm water in tufts of fine silky needles and, as with many other bromocamphosrsulphonates the warm solution becomes milky when the salt separates unless it is free from its optical isomeride.The freshly crystallised salt contains water, probably one molecular proportion but it was impossible to obtain accurate determinations on this point since the salt rapidly loses water in the air and the air-dried salt is anhydrous. 1.69 of the salt roughly dried in the air lost 0.544 a t looo. Loss=3.2 whereas 1H,O requires a loss of 3.1 per cent. When the freshly crystallised salt is heated in a melting-point tvbe i t partly liquefies a t a b u t looo and finally melts a t 229-230°. It is moderately solubsle in water more readily so in alcohol; it is also soluble in acetone o r ethyl acetate but insoluble in carbon tetrachloride or ether. d-neoMe thy Zh ydninda min e hydrochloride Cl,Hl *NH,,HCl pre -pared from the pure bromocamphorsulphonate was dried a t looo and examined polarimetrically in aqueous solution in a 200 mm.tube. Wt. of salt. Vol. of solution. b a. 1.1". 0.5200 ............ 25 C.C. 0.13' 3.1' 5 . 7 O 0.4268 ............ 1 9 0.10 3-0 5.5 d-neo:Ue t h ylh ydriizdam ine hydrogen tart rate , C1,H1,'NH27@aH,0,,H207 is much mom readily soluble in water than the hydrogen tartrate of the 2-base and crystallises in aggregates of needle-like prisms : 1-2146 air-dried salt lost 0'0726 a t looo. When heated in a melting-pint tube the salt sinters a t about The following resu1t.s were I]I,o=5.9. The above formula requirm H,O=5*71 per cent. 900 and finally melts a t 166-167O BRIGGS CHROMATOCOBALTIAMMINES. 67 obtained with aqueous solutions of the anhydrous salt in a 200 mm. tube : Wt. of salt. Vol. of solution. a. [alD* 0.3122 ............ 26 C.C. 0.40' 16.0' 47.6' 0.3328 ............ 9 9 0.43 16.2 48.1 Taking the molecular rotation of the tartaric acid ion in its hydrogen salts as [MIL 42O these results give1 .[MI 5.5O and 6.1° respectively for the base. d-neoMe t h ylhydrindamin e d-camphorsulphonat e, Cl,Hll* NH,,Cl,,Hl,O S0,K crystallises from water in felted masses of needles which melt and decompose a t 195-205O. The salt is extremely readily soluble in water and readily so in alcohol or chloroform. It is sparingly soluble in ethyl acetate and practically insoluble in ether, A sample dried a t looo examined in aqueous solution in a 200 mm. tube gave the following result 0.6176 gram in 25 C.C. of solution gave a 0'73O [a], 14.8O [MI 56*1°. Taking the molecular rotation of the acid ion as 49O that of the base is [MI 7O. UNIVERSITY COLLEGE, NOTTINUHAM. [Received December 16th 1918.

ISSN:0368-1645    

DOI:10.1039/CT9191500061

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

BRIGGS CHROMATOCOBALTIAMMINES. 67 VI. -ChromatocobaltiammirLes. By SAMUEL HENRY CLIFFORD BRIGGS. PREVIOUS investigations have shown that the chromate radicle possesses considerable residual affinity and has a strongly marked tendency to form complex salts (Briggs Zeitsch. anorg. Chem., 1907 56 246; 1909 63 325; Groeger ibid. 1908 58 412). It was therefore to be expected that the chromatocobaltiammines would be a well-defined and stable class of substances containing one or more non-ionisable chromate radicles. As soluble compounds containing a non-ionieable chromate radicle have not previously been described the study of the chromatocobaltiammines was under-taken in order to compare the properties of the chromate radicle in non-ionisable combination with those of- the ionisable radicle in the ordinary chromates.The chromatocobaltiammines are readily prepared by the action of potassium chromate on the corresponding aquo-compounds in solution. Thus when a solution of potassium chromate is added to a warm solution of an aquopentamminecobaltic salt a chromato-0 68 BRIGFGS CHROMATOCOBALTIMMINES. pntamminecobaltic salt (I) crystallises out on cooling. The nitrate, chloride and chromate of this series were obtained in a pure condition. The chromatotetramminecobaltic salts (11) are formed in a similar manner and the chromate dichromate and nitrate were prepared in a pure state. When a solution of a diaquotetramminecobaltic salt is treated with an excess of potassium chromate trichromato-octamminedicolbalt (111) crystallises out on keeping.Trichromato-octamminedicobalt7 is isomeric with chromatotetramminecobaltic chromate (IV) but the two compounds are very different. The former is almost completely insoluble in water and forms greenish-black crystals containing five molecules of water of crystallisation, whilst the latter is obtained as a greenish-brown precipitate with three molecules of water of crystallisation; it is moderately soluble in water and its solution gives the reactions of the chromate ion. Attempts to prepare chromatotriammine compounds by the action of potassium chromate on triaquotriammineoobaltic nitrate were not successful the product being chrornatohydroxotriamminecobalt (V), which however was not obtained in a completely pure condition. It therefore appears that when more than two molecules of ammonia in the hexamminecobaltic radicle ar’e replaced by the chromate radicle the products are unstable in the presence of water and undergo hydrolysis.This explains why endeavours to prepare putassi um cobaltic chromate K3Col( CrO& by oxidising cobaltous salts in the presence of potassium chromate failed cobaltic hydr-oxide and potassium dichromate being obtained. The formation of chromatohydroxotriamminecob~alt in the above manner also supports the view that the basic chromates are hydroxo-compounds in accord-ance with Werner’s theory of basic salts (“ Neuere Anschauungen auf dem Gebiete der anorganischen Chemie,” 3rd led. pp. 177-178). Some evidence was obtained which pointed to the existence of a chromatoaquotriammine series (VI) a compound being prepared which had the composition of chromahaquotriamminecobaltic dichromate : (11.) (111.) w.1 w.1 (VI.) In the chromatopentammine- and chromatotetrammine-cobaltic salts the chromate radicle in the complex is non-ionisable no pre BRIGGS CHROMATOCOBALTIAMMINES.69 cipitate being obtained when silver nitrate is added to cold freshly prepared solutions of the pure nitrates. If the mixture is allowed to remain for some time however silver chromate is slowly deposited showirlg t.hat the chromato-salts have a tendency to pass into the corresponding aquo-salts as seen from the equation : I f the eolution is heated the change takes place a t once and silver chromate is immediately precipitated. The chromate radicle in these1 compounds reacts with hydrogen ions in the same way as in the ordinary chromates.When an acid is added t o a solution of a chromatopentammine or chromato-tetrammine salt the complex is decomposed as seen from the change in colour of the solution. I n the chromatopentammine salts the chromate radicle fills one co-ordination position according to Werner's theory whereas in the chromatotetrammine salts it fills two positions. The entrance of the chromate radicle into the complex is accom-panied by marked intensification of colour and all the chromato-cobaltiammines are deeply coloured substances. E X P E I X I M E N T A L . P e n t a m rn in e S e r i e s. Chroma t opeittammineco bal tic Nitrate (Co;:?) NO,.-Carbon-atopentamminecobaltic nitrate was converted into aquopentammine-cobaltic nitrate and potassium chromate was then added to the solution the details of the preparation being as follows.Carbonatopentamminecobaltic nitrate (2.5 grams) was dissolved in 100 C.C. of water a little dilute nitric acid was added and the solution was gently warmed to expel carbon dioxide. The liquid was then just neut,ralised by potassium hydroxide diluted to 300 c.c. and heated to 60-70°. One and a-half grams of potassium chromate in 100 C.C. of water also heated t o 60-70° were added and the clear solution was allowed t o crystallise. The chromatopentamminecobaltic nitrate sepa'rated in brownish-red, acicular cryst.als (2.2 grams) which were collected washed with a little water and dried in the air. Found Co = 18.51 ; Cr03= 31.74 ; NH,= 26-36.(COT::) NO requires c*o = 13.35 ; CrOB = 31.05 ; NH3 = 26.44 per cent. The salt was moderately soluble in cold water and the freshl 70 BRIQQS CHROMATOCOBALTIAMMINES. prepared solution was not precipitated by silver lead or barium salts but precipitation took place a t once on heating. The chromate radicle is therefore situated in the complex as shown by the above formula and the salt is isomeric with Jorgensen’s nitratopent-amminecobaltic chromate (CoS”g?)CrO ( J . F. CJlem. 1881 [ii], 23 245). Chromat opentammhLeco baltic Cht?oride (C‘of;$) Cl.-Chloro-pentamminecobaltic chloride was converted into aquopentammine-cobaltic chloaide by Werner’s method (Bey. 1907 40 4104) and this was treated with potassium chromate. Twenty-five grams of c’hloropentamminecobaltic chloride were heated with 625 C.C.of water and 62.5 C.C. of concentrated aqueous ammonia until the chloride was completely dissolved. After cooling, the liquid was just neutralised with hydrochloric acid and heated to 60°. Sixteen grams of potassium chromate in 500 C.C. of water, also heated t o 60° were then added and the mixture was allowed to cooll. After crystallisation was complete the salt was collected, washed with a little water and dried in the air. Twenty-three grams of brownish-red crystals ( A ) were thus obtained. The mother liquor was heated t o 50° and 4 grams of potassium chromate dis-solved in a little water were added. On cooling 1.2 grams of a second salt ( B ) were1 obtained in yellowish-brown prisms almost insoluble in cold water but readily soluble on warming t o give a yellow solution.The salt A was anhydrous but B contained water of crystallisation ; otherwise the salts were similar in composition as seen from the analyses : A . Found Co = 19.86 ; CrO,= 33.97 34.27 ; C1= 12.02 ; NH3= 27.30 27.15 27-08. (CO$$~)CI requires Co = 19.96 ; Cr3 = 33-83 ; C1= 12.00 ; NH = 28.81 per cent. B. Found Co=16.91; C1=9*80; Cr03=29*94; NH3=26*6; H20 = 13.95. 2 C O ~ ~ ~ Cr0,,5H20 requires Co = 17.31 ; C1= 10.41 ; CrO = 29.36 ; ( cl,> NH = 25.0 ; H,O = 13-22 per cent. The solution of the salt ,4 on addition of silver nitrate gave a copious precipitate. Tliis was filtered off and on treatment with dilute nitric acid was found to consist of silver chloride coloured by the presence of a trace of silver chromate.The reddish-yellow filtrate on heating deposited a precipitate of silver chromate Th BRIGCIS CHROMATOCOBALTIAMMINES. salt A was therefore chrornatopentamminecolbaltic The solution of the salt I3 on addition of silver nitrate 71 chloride, gave a red precipitate which was filtereld off the filtrate being only faintly coloured. The precipitate consisted of silver chromate. It dis-solved in dilute nitric acid leaving only a trace of silver chloride. The salt B was therefore a hydrated chloropentarnminecobaltic Vari'ous preparations of the salt A (chromatopentamminecobaltic chloride) were made but? in all cases the ammonia content was low. The salt conld not ble purified by crystallisation from hot water as it was then fonnd to contain a little of the corresponding chromate, which is very sparingly soluble in water.The reason for tlie low percentage of ammonia could not be ascertained, and this is all the more remarkable as the salt on treatment with silver chromate gave t'he corresponding chromate in a high degree of purity. Chromatopeiztamminecobaltic Chromate ( C O ; ~ ? ) T r O, 3H20. -Two grams of silver nitrate were precipitated in-the cold with 1 gram of potassium chro,mate and the precipitate was washed two or three times by decantation. The supernatant liquid was separated as far as possible by decantation and the precipitate was then poured into a solution of 3 grams of chromatopentamminecobaltic chloride in 150 C.C. o,f water a t 60° the mixture being well shaken.After a few minutes the silver chloride assumed a dense form and crystallisation began. The silver chloride was then rapidly col-lected and the filtrate which no longer gave the reactions of the chloride ion was allowed to! crystallise. Chromatoperttammine-cobaZtic chromate separated in glistening scaly crystals similar in colour to silver chromate. The crystals consiiste'd of a trihydrate which lo& 22 molecules of water after expoisure o'ver sulphuric acid in a vacuum f o r two or three weeks (Ioss=7*16. 2$H,O require a loss of 7-17 per cent.). The resulting The yield was 1.5 grams. hydrate 4 (Co cr04 ) Cr04,H,0 became anhydrous above looa. The 5N% 2 complete analysis of the trihydrate gave : Found Co = 17.48 ; CrO,= 43-64 ; NH = 24.83 ; H,O = 7.64.( CoiG$8)2(ki ),,3 H2( J requires Co = 17.09 ; CrO = 43 6 ; NH = 24.6s ; H20 = 7.83 per cent 72 BEUQGS CHROMATOCOBALTIAMMINES. Tetrammine Series. Carbonatotetramminecobaltic nitrate was prepared by Jorgensen’s method (Zeitsch. anorg. Chem. 1892 2 ZSZ) and this was con-verted into diaquotetramminecobaltic nitrate by acidification of its solution. On treating the solution of diaquotetramminecobaltic nitrate with potassium chromate either chromatotetrammine-cobaltic nitrate chromatotetramminecobaltic chromate or tri-chromato-octamminedicobalt could be obtained in the pure state, according to the conditions employed. Chromatotetramminecobaltic Nitrate 2(Co~~~)N03,H20.-A solution of 4 grams of carbonatotetramrninecobalti; nitrate in a little water was treated with dilute nitric acid warmed gently to expel carbon dioxide just neutralised with potassium hydroxide, and the volume made tip to 40 C.C.Twenty grams of ammonium nitrate were dissolved in the liquid and a solution of 1.2 grams of potassium chromate in 10 C.C. of water was added drop by drop in the cold with vigorous stirring. The stirring was continued for a minute or two until crystallisation was complete and the dark reddish-brown deposit was then immediately collected washed with a little water and dried in the air. The yield was 0.9 gram. The product was a hemihydrate which lost its water of crystallisation after exposure for two days over sulphuric acid in a vacuum. Found Co = 18.86 ; CrO = 31.68 ; NH,= 21.34 ; H,O = 3.67. ~ ( C O F ~ ~ ~ ) N O ~ ‘ I requiresco- 18.77 ; Cr0,=31*83; KH3= 21.69 H,O = 2.87 per cent.The salt was moderately soluble in water giving a deep brown solution. Silver barium or lead salts did not precipitate the freshly prepared cold solution but precipitation to,ok place a t once on heating. The cold solution was also completely precipitated if allowed to remain for several days after the addition of the reagent, showing that the chromate radicle is gradually eliminated with the formation of a diaquotetrammine salt for example, Chromat otetramminecobnl t ic Chroma t e ( C O ; ~ ~ ) Cr04,3H20.-Four grams of carbonatotetrarnminecobaltic nitrate in 80 C.C. of water were converted into diaquotetrami~~inecobaltic nitrate aa described above in the preparation od chromatotetramminecobaltic nitrate.To the cold neutral solution of diaquotetramminecobalti BRIBBS CHROMATOCOBALTIAMMINES. 73 nitrate thus obtained (100 c.c.) 3 grams of potassium chromate, dissolved in 50 C.C. of wat'er were added with vigorous stirring. A brown crystalline precipitate was formed which waa collected immediately washed with water and dried with alcohol and ether. The! yield was 2.8 grams. The salt contained three molecules of water as water of crystal-lisation only being readily evolved when the. substance was exposed in a vacuum over sulphuric acid. The salt was sparingly soluble in water and its solution was immediately precipitated by silver nitrate showing that some of the chromate content was ionis-able. It follows from these facts and the analyses that the com-pound must have the formula assigned to it.Found Col= 18.14 ; CrO,= 45'31 ; NH = 20.61 ; H,O = 8-26. ( C O ~ % ~ ) F ~ ) ~ H ~ O ; Co=17*97; Cri),=45.71; NH,=20*77; H,O = 8.26 per cent. Yrichr om at 0- o c tamminedico bal t , -Two grams of carbonatotetramminecobaltic nitrate in 30 C.C. of water were converted into diaquotetramminecobaltic nitrate in the manner already described and the cold neutral solution (50 c.c.) was added with stirring to a cold solution of 5 grams of potassium chromate in 50 C.C. of water. The clear liquid deposited a greenish-black crystalline substance on keeping. This was collected washed with a litble water and dried in the air. Found Co=17*14; Cr03=43.32; NH3=19'44; H20=13'05. C O ~ N H ~ ( C ~ O ) ~ ~ H ~ O requires Co= 17-04 ; Cr03= 43.33 ; NH = 19-68 ; H,O = 13-01 per cent.The five molecules of water were readily evolved on exposing the compound in a vacuum over sulphuric acid and all were therefore water of crystallisation only. I n view of the facts ascertained with regard to chromatotetramminecobaltic chromate and described above it follows that this isomeric compound must be a non-ionis-able octamminedicobalt derivative. Its almost complete insolu-bility in water affords further confirmation of this view. Again, since in the diaquotetramminecobaltic salts the water molecules are in the " cis" position (Werner " Neuere Auschauungen auf dem Gebiete der anorganischen Chemie," 3rd ed. p. 347) this tri-chromato-octamminedicobalt must also have the chromate radicles in the " cis " position and is therefore a 1 1' 2-2~-trichromatc-octammz'redicobalt pentahydrate.Attempts to prepare the corre-sponding '' tra?is " compound by various methods were unsuccessful. J3 74 BRIGGS CHROMATOCOBALTIAMMINES. CrO Chroma t o t e tram mineco b a1 t ic Dic hro ma t e ( C'04 H43),Cr20,,2H20. -Four grams of carbonatotetramminecokaltic nitrate were con-verted into diaquotetramminecobaltic nitrate as described ab,ove, and the neutral solution (80 c.c.) wts added slowly with stirring to a cold solution of 8 grams of potassium dichromate in 80 C.C. of water. The precipitate was immediately collected washed with a little water and dried in the air. The yi,eld was 1.9 grams. Three separate preparations were analysed and the ammonia content was low in every case for some reason that could not be ascertained.Found Co=15*94; CrO,=53*41 54-01; NH,=17*48 16.6 16.4; (C!O~;~~),C~&,~H~O requires Co= 15.97 ; CrO = 54.19 ; XH3= H20 = 4.98 4.76 5.04. 18.4 ; H20 = 4.88 per cent. The threle molecules of water were readily given off in a vacuum over sulphuric acid and all were therefore water of crystallisation only. From the proportion ,of cobalt t o chromium (2Co :4Cr) it is evident that the salt is chromatotetramminecobaltic dicliromate, ( C O G ~ ~ ) C ~ ~ O and not dichromatotetramminecobaltic chromate, ( C O Y ~ $ ) ~ C ~ O in which the propo,rtioas am 2Co 5Cr. Conse-quently the dichr0mat.e radicl'e is ionisabmle and the chromate radicle non-ionisable. The salt was moderately soluble in water, and the solution was immediately precipitated by silver and barium salts.Triammine Series. Chromatohydroxotriammiaecobalt.-Two grams of trinitratotri-amminecobalt prepared by Jorgensen's method (Zeitsch. anorg. Chem. 1895 5 185) were dissolved in 40 C.C. of cold water and the solution was added to a cold solution of 6 grams of potassium chromate in 40 C.C. of water. The brown precipitiate (1) was col-lected wasled with cold water and dried in the air when it weighed 1.7 grams. The filtrate on spontaneous evapofation deposited crystals of potassium dichromate as well. as of potassium chromate. Two other preparations were made (2 and 3) in which 1 gram of potassium chromate in 10 C.C. of water was mixed with 6.25 C.C. of potassium hydroxide solution (1 C.C.= 0.0448 gram KOH) and the mixture was poured into a solution of 1.5 grams of trinitratotri-amminecobalt in 10 C.C. of cold water. The analyses gave BRIUUS CHBOMATOCOBALTIAMMINES. 75 Foun'd (1) H,0=11*5; CrO,=36.3; Co=22'9; NH3=15*1. (2) H20=11*4; CrO,=34*5; Co=22*5; NH3=16.8. (3) NH,= 16.7. ( C b b ~ ) 2 € € 0 requires H,O=12.9 ; CrO,=35*8; Co=21*1 ; Although impure the compound was clearly a hydrated chromato-hydroxotriamminecobalt. Chromatoapuotrianaminecobdt~c Dichromute.-Two grams of tri-nitratotriamminecobalt in 10 C.C. of cold water were added t o a solution of 3 grams of sodium dichromate in 10 C.C. of water and the mixture was treated with a solution of 0.75 gram of anhydrous sodium chromate in 10 C.C. of water in the cold.A copious brown precipitate was formed which was allowed to settle and then col-lected washed with a little water and dried with alcohol and ether. The product which weighed 1.4 grams was only sparingly soluble in cold water. I n a vacuum over sulphuric acid it lost 3 mole-cules of water after three days and a further quarter molecule after eighteen days the weight then remaining constant. The analysis agreed cloeely with the formula given below. Found 3H20=7*22; 3$H20=8.16; Co=16.06; CrO,=54*09; NH,= 18.3 per cent. NH3= 13.63. ( 2 ~ 4 ) ~ r 2 0 7 2 H 2 0 requires 3HaO = 7.30 ; 34H,O = 7.91 ; Co = 15.93 ; CrO = 54.04 ; NH = 13.81 per cent. iVote m the Preprution of Carbonat~pentarn?ninecobultic Nitrate. The following method of preparation was found'to be more oon-venient and more economical than that described by Werner and Goslings (Ber.1903 36 2380). Twenty grams of cobalt carbonate were dissolved in the smallest possible quantity ,of dilute nitric acid and the clear solution (100 c.c.) was poured into a mixture of 250 C.C. of concentrated aqueous ammonia and 100 grams of powdered ammonium carbon-ate. Air was drawn through for two or three hours and the solu-tion was then allowed t o remain f o r twenty-four hours. The mix-ture was heated for twenty minutes in a porcelain dish on the water-bath with frequent addition of a small piece of amm,onium carbonate. The brown colour of the liquid changed t o deep red, and the mixture was allowed t6 remain until crystallisation was complete. After filtration and washing with a little water the salt D* 76 JONES CILYCERYL METHYL ETHER DINITRATE was digested with cold water to remove any ammonium carbonate still present. The air-dried product weighed 21 grams. (Found, Co= 20.54 ; NH = 29.63. (Co5z:3) NO,,H,O requires Co = 20.76 ; NH3=29.95 per oent.) The water was not given off a t looo or in a vacuum over sulphuric acid a t the ordinary temperature. [Received October 23rd 1918.

ISSN:0368-1645    

DOI:10.1039/CT9191500067

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

76 JONES CILYCERYL METHYL ETHER DINITRATE VII.-Glyoer~l Methyl Ether Dinitrate (a- Methylin Dinitrate .> By DAVID TREVOR JONES. DURING recent years considerable attention has been devoted to the study of the mono- and di-nitrates of glycerol and their chlorides and ethers. The interest in these substances has been stimulated by the technical possibilities which they appeared to offer as ingredients of non-freezing nitroglycerin blasting com-positions. Among the substances investigated have been the di-nitrate of monochlorohydrin (Kast Zeitsch. yes. Schiess- u. Sprenlystoffw. 1906 1 227) which has been more o r less extensively used in such explosives as gelatin astralit gelatin westfalit etc. The mono- and di-nitrates of glycerol have been very exhaustively studied by Will (Ber.1908 41 1107) who commenced the in-vestigation of these substances with the above-mentioned technical object in view. The dimethyl and diethyl ethers of glycerol mono-nitrate have been described by Paternb and Benelli (Gaazetta, 1909 39 ii 312) whilst Vender has described the dinitrates of monoacetin and monoformin (Zeitsch. yes. Schiess- u. S p e n g s t o f f u r . , 1907 2 21). Glyceryl methyl ether dinitrate which is here -described was prepared by the direct nitration of the a-monomethyl ether of Grun and Bockisch (Ber. 1908 41 3471). OMe.CH,*CH(OH)*CH,*OH + 2HN0 -+ OMe*C'H,~CH(NO,)*CH,*NO + 2H20. The product which was readily isolated was found t o solidify after being well supercooled and stirred. It is a powerful ex-plosive having about two-thirds the strength of nitroglycerin.It is however much less sensitive to shock although rather more readily exploded by heat. Its effect in lowering the freezing point of nitroglycerin is much the same as that of molecular concentra (a-METHYLIN DINITRATE .) 77 tions of monochlorohydrin dinitrate (Kast Zoc. c i t . ) and of ethyl nitrate (Nauckhoff Zeitsch. angew. Chem. 1905 18 21). All these values however are in complete disagreement with the value for the freezing-point constant of nitroglycerin as calculated from a carefully conducted determination of its latent heat of fusion (Hibbert and Fuller J . Amer. Chem. SOC. 1913 35 979). The subst,ance did not appear to exist in a second or labile form corresponding with the labile form of nitroglycerin.E x P E R I M E N T AL. Glyceryl a-monomethyl ether was prepared by Griin and Bockisch’s method (Zoc. cit.). The1 product distilled at l2Oo/ 18 mm. and the yield was 127 grams or from 200 grams of mane chlorohydrin 66 per cent. of the theoretical. The same yield was obtained on repeating the experiment. Glyceryl Methyl Ether Dinitrate. Sixty-three grams of glyceryl a-monomethyl ether were gradu-ally added to 480 grams of a mixture of nitric and sulphuric acids (HNO = 38.6 H,SO = 59.0 H,O = 2.4 per cent’.) which was cooled in icewater during the nitration. The initial temperature was 13O. During the operation the temperature was allowed to rise to 20° and was maintained a t that point until the end. The nitration proceeded quite smoothly and was easily controlled by regulating the addition of the glyceryl methyl ether.The time occupied by the nitration was from twenty to twenty-five minutes. The product was completely soluble in the mixed acid and the mixture; was slowly poured into 800 C.C. of water the temperature being allowed to rise to 40°. The bulk of the dinitrate separated, and after remaining for some little time the bulk of the aqueous layer was poured off and preserved for extraction. The residue containing the dinitrate was neutralised with a semi-saturated solution of sodium carbonate. The dinitrate was then run off from below the neutralised aqueous layer being added to the diluted acid which had been previously poured off. The dinitrate was then washed three times a t 50° with an equal bulk of 5 per cent.sodium carbonate solution then three times with water and was finally dried in a desiccator over calcium chloride. The yield was 75 grams or 64 per cent. of the theoretical. The neutralisd aqueous washings were extracted with ether and the ethereal solution was washed with 5 per cent. sodium carbonate solution, dried with calcium chloride filtered evaporated under diminishe 78 * pressure and preserved over calcium chloride in a desiccator. I n this way a further yield of 13.9 grams was obtained the total yield being thus 88.9 grams or 77 per cent. of the theoretical. The dry liquid constituting the first and major portion of the yield was analysed by the combustion method but on- account of its highly explosive nature1 the weighed,out substance was first converted into a weak dynamite by mixing with excess of pre-viously ignited kieselguhr the dynamite in turn being mixed with roughly powde'red copper oxide and introduced into t3he combus-tion tube.The nitrogen was estimated by the nitrmeter method using sulphuric acid as in the analysis of guncotton: 0.1397 gave 0.1248 COP and 0.0514 H20. C=24*36; H=4.03. 0.5492 , 132.3 C.C. NO a t 16O and 755 mm. N=14*15. 0.638 in 20.45 benzene gave At= - 0.833O. JONES GLYCERYL METHYL ETHER DINITRATE The combustion proceeded normally. M.W. = 188. C,H,O,N requires C= 24-28 ; H =4*08 ; N = 14.29 per cent. M.W. = 196. The subst.ance was therefure undoubtedly a-met-hylin dinitrate. GZyceryZ methyl ether dinitrate crystallises in white monoclinic prisms melting a t 24O.As first obtained it was a clear colour-less liquid which became pale yellow on keeping. It crystallised with difficulty and remained liquid even with occasional shaking, for more than two years in a magazine maintained a t 15-21O. It distilled a t 124O/18 mm. that is a t approximately the same temperature as the glyceryl methyl ether from which i t was derived, and some 22O lower than glyceryl dinitrate the corresponding alcohol. It is therefore more volatile than nitroglycerin and when tested a t looo on a watch-glass it) was found to volatilise a t from seven to eight times as rapidly. The liquid has D: 1.374 and ng 1.4478. It is soluble in benzene toluene acetic acid methyl and ethyl alcohols chloroform ether or acetone and insoluble in carbon disulphide or light petroleum.It gelat.inises nitro-cotton rapidly a t the ordinary temperature, and after warming it yields a gelatin softer and more plastic than that obtained from nitroglycerin. The chief interest of this substance lies in its explosive proper-tiee as compared with those of nitroglycerin. It has about t w e thirds the power of nitroglycerin although i t is much less sensitive to shock. Its comparative insensitiveness was demonstrated by submitting to the fall-hammer test' unfrozen dynamites each con-Both Eiubstances were placed under a Ateel disk and subjesbd to tha . tlaining three parts of explosive to one part of kieselguhr @-METHYLIN DINITRATE.) 79 impact of a weight of 1 kilogram falling from a measured height. The results are set forth in the following table : Dinitrate.Nitroglycerin. Height of fall. cm. Detonations. Failures. 100 2 8 95 1 9 90 1 9 85 0 10 Height of fall. cm. Detonations. Fdluree. 30 10 0 20 10 0 16 9 1 10 0 10 The solid substance was very insensitive. It did not explode even when scratched with the sharp edge of a thin melting-point tube. On the other hand the dinitrate proved to be more easily exploded when heated than did nitroglycerin. When heated in a glass test-tube in a metal-bath the temperature being raised a t the rate of 5* per minute it was observed to explode a t 182O the %ri-nitrate exploding at' 192O. Comparative power tlests of nitroglycerin and methylin dinitrate dynamites were made with the Trauzl lead block and mortar tests.I n the lead block the dinitrate dynamite gave an expansion of 22.9 c.c. a similar charge of nitroglycerin dynamite giving 30.0 C.C. I n the mortar test the relative powers indicated by the ballistic pendulum were 93.76 kilogram-metres (678 foot-lb.) for the dinitrate dynamite as compared with 124.43 kilogram-metres (900 foot-lb.) for a similar charge of nitroglycerin dynamite. Methylin dinitrate t-herefore would appear to have rather more than two-thirds the strength of nitroglycerin. I n order ta determine the lowering effect of the dinitrata on the freezing point of nitroglycerin a form of apparatus was adopted similar to that used by Kast (Zoc. cit.) for determining the melting points of the nitroglycerin isomerides and by Hibbert (Eie9hth Tnternutionnl Congress of Applied Chemistry 1912, About 5 C.C.of the mixture were inserted in a test-tube (15 x 1 an.) which was fitted into a slightly larger tube whereby the glyceryl nitrates were protected by an air-jacket from the too rapid action of the freezing mixture. The freezing agent con-sisted of ice where mixtures of higher melting point were con-cerned and of ice and salt for those of lower melting point. The thermometer was allowed to stand in the mixture direct contact between glass and glass being prevented by enclosing the lower portion of the thermometer bulb in a band of elastic. The stirrer consisted of a flexible piece of platinum wire which was attached t o a weighted string wound over a simple pulley and fastened a t IV 37) 80 JONES BLYOERYL METHYL ETHER DINITRATE.the further end to the outer edge of a wooden disk rotated by a motor. The liquid was first supercooled to the extent of aboutJ 4O or 5O. It was then inoculated with a small quantity of a frozen mixture of nitroglycerin wood-pulp and sodium nitrate and vigorously stirred. The maximum temperature was then carefully noted and taken as the freezing point. It will be seen that the values found for the molecular depression constant for nitroglycerin vary from 72.4 to 81.0 thus differing not very greatly from those obtained by Nauckhoff (Zoc. c i t . ) and by Kast (Zoc. cit.) with ethyl nitrate and monochlorohydrin dinitrate respectively These numbers are in fair agreement with the value 70.5 for the freez-ing-point constant for nitroglycerin obtained by Nauckhoff (Zoc.c i t . ) from a determination of its latent heat of fusion. Nauckhoff’s method was however admittedly defective and his r e d & differ very considerably from those of Hibbert and Fuller (Zoc. cit.) who found the latent heat of fusion ( h ) o’f nitroglycerin a t Oo to be 33.2 calories. Corrected to 13O the melting point of stable nitro-glycerin this would become 33*2+13*0 (c,-cz) where c1 and c2 art3 the specific heats of solid and liquid nitroglycerin respectively. Accepting Nauckhoff’s values of 0-356 and 0.315 for these the latent heat of fusion of nitroglycerin a t 13O would be 33.2+ 13.0 (0.356 - 0.315) = 34-33. Hence the freezing-point constant R P - 0,1991 x (2’73+ 13)2 = 48,5. lOOh 100 x 34.33 ~ -The results are set forth in the following table which includes Nauckhoff’s and East’s values derived from ethyl nitrate and chlorohydrin dinitrate : Molecular depression constant.Composition of - liquid. Calculated -’- from latent Nitro- Methylin Depression heat (Hib-glycerin. dinitrate. of freezing Calculated bert and Grams. Grams. point. (A) from A Fuller). 31-69 1.802 2-10 72.4 48-5 15-31 1.748 4.4 75.6 Y ? 8-22 1.729 8.7 81.0 9 9 Chloro-hydrin dinitrate. 21 2.1 4.4 88.4 $2 21 6.3 9.4 60.7 21 4.2 6.4-7.2 62.7-70’5 Ethyl nitrate. 74.1 76. THE INFLAMMATION OF MIXTURES OF ETHANE AND AIR. 81 Attempts to obtain a labile form of the substance analogous to that of nitroglycerin were made. The liquid was mixed with glass wool and supercooled to varying degrees with continual stirring with a glass rod. When some of the supercooled liquid which had not been previously frozen was inoculated with a trace of this product the solid obtained invariably crystallised a t 2 4 O . The author desires to express his indebtedness to Messrs. Nobel’s Explosive Co. and to Mr. W. Rintoul the manager of their Research Section for the facilities accorded to him for the carry-ing out and publication of this work. ARDEER. [Received November 7th 1918.

ISSN:0368-1645    

DOI:10.1039/CT9191500076

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

THE INFLAMMATION OF MIXTURES OF ETHANE AND AIR. 81 VIIL-The Inflammation qf Mixtwes of Ethane and Air in a Closed Vessel The Efects of Turbulence. By RICHARD VERNON WHEELER. WHEN describing the inflammation of mixtures of methane and air i t was noted that the speed a t which flame spreads through the mixture in a closed vessel is demonstrably dependent on the degree of mechanical agitation imparted to the mixture as indeed is the speed of flame in all combustible mixtures and under all conditions other than those existing during the propagation of the explosion wave. This important fact appears first to have been observed or a t all events first commented on by Schloesing and de Mondesir about the year 1864. Their experiments which involved an extended study of the mode of propagation of flame were carried out mainly with mixtures of carbon monoxide and air and were undertaken in connexim with a research on the working of gas engines.Mallard and Le Chatelier to whom the results of the experiments were communicated verbally have thus described the’m (Ann. des Mines, 1883 [VIII] 4 298): “Ces recherches ont inis en 6vidence un fait d’une grande im-portance l’influence de l’agitation du melange gazeux sur la vitesse de propagation de la flamme. Des melanges trhs lents (et par cette expression nous entendrona ceux dam lesquels la vitesse dei propaga-tion est faible) peuvent donner lieu B des propagations pour ainsi dire instantan& c’est-&-dire B de veritables explosions quand on provoque au moment de l’inflammation une agitation interieure tr6 82 WHEELER THE INFLAMMATION OF MIXTURES OF ETHAN.E AND vive telle que celle que I ’ m obtient en faisant d6boucher au milieu d’une mass8 gazeuse en r e p s un jet de gaz anim6 d’une grande vitesse.” These observations appear to hav’e been overlooked or forgotten until the subject of the agitation or turbulence of gaseous mixtures became of manifest importance during the investigation of gaseous explosions instituhed by the British Association f o r the Advance-ment of Science. New experiments on the subject by Dugald Clerk m d Hopkinson are recorded in the Fifth Report of the Committee on Gaseous Explosions (Rep. Brit. L 4 ~ ~ ~ ~ . 1912 201). To quote from hid Gustave Canet lecture (Junior Institution of Engineers 1913) Dugald Clerk “had long ago observed that gas engines would ’have been impracticable had the rates of explosion been the same in actual engine cylinders as in closed-vessel experi-ments.” During his experiments in 1912 he “found that the rate of explosion rise in the same engine varied with the rate of revo-lution increasing with increased number of rotations per minute, and was due to the turbulence or eddying caused by the rush of gases into the cylinder during the suction stroke which persisted during the compression stroke.” By drawing in a charge of mixture into the gas-engine cylinder in the ordinary way and then tripping the valves and compressing and expanding the charge for one or two revolutions before igniting it the turbulence was given time to die away.It was found that the effect of thus damping down turbulence was to retard the rate of inflammation of the mixture1 to a remarkable extent.For example with a mixture of coal-gas and air containing about 9.7 per cent. of gas ignition in a gas-engine cylinder under normal conditions a t the end of the first compression stroke (the engine being run a t 180 revolutions per minute) resulted in the maximum pressure being attained after 0.037 sec. ; whilst when ignition was a t the end of the third cornpression stroke after the charge had been expanded twice and turbulence had subsided the time taken foir the attainment of maximum pressure was 0.092 sec. Hopkinson experimented on the effects of turbulence a t the same time as Dugald Clerk using a cylindrical vessel 30.5 cm.in diameter and 30.5 cm. long. A small fan was mounted a t the centre of the vessel and comparison was made of the results of igniting similar mixtures with the fan at rest ahd in motion. With mixtures of coal-gas and air containing 10 per cent. of gas the times that elapsed between ignition and the attainment of maximum pressure were (1) with the fan a t rest 0.13 sec.; (2) with the fan running at 2,000 revolutions per min. 0.03 sec.; and (3) with the fan rucning a t 4,500 revolut’ions per min. 0-02 sec AIR IN A CLOSED VESSEL THE EFFECTS OF TURBULENCE. 83 Simultaneously with and independently of the experiments thus made on behalf of the Gaseous Explosions Committee of the British Association a problem under investigation for the Explosions in Mines Committee of the Home Office was found to involve a study of the effgcts of turbulence on the inflammation of gaseous mix-tufes.The prolblem was to determine the effect if any of the presence of incombustible dusts in suspension on the limits of inflammability of mixtures of firedamp and air. A series of experi-ments on the ignition of mixtures near the lower limit of inflam-mability was made with a spherical vessel of about 4 litres capacity (described in T. 1918 '113 855) provided with a fan which could be rotated a t a high speed so as to agitate the mixture and maintain dust in suspension. Naturally the fan was rotated whether dust was present or absent 301 as t o ensure that the comparative experi-ments required should be made under as far as possible identical conditions.The pronounced effect of turbulence or agitation of a gaseous mixture on the speed a t which flame travels through it thus became manifest for 'many experiments had previously been made with similar mixtures in the same sphere without the fan. The fan had four blades and was attached to a horizontal shaft passinq through an air-tight gland near the bottom of the sphere. Each blade extended for 7.5 cm. alonq the' shaft and had a maxi-mum width of 2.5 cm. the edge having a radius of curvature of 9.5 cm. The shaft was so fitted that there was a clearance of 1 cm. between the side of the sphere and the edges of the fan-blades. A slight helical twist was given to each blade. Several experiments were made with mixtures of ethane and air near the lower-limit of inflammability which with ignition a t the centre of a closed spherical vessel of glass of 2.5 litres capacity is 3.10 per cent.ethane. With 3.0 wr cent. of ethane flame travels slowly throughout nearly the whole of the (nm-turbulent) mixture in such a vessel; and with 2.9 and 2.95 per cent. of ethane flame spreads through about one-third of the mixture (T. 1911 99, 2026). It will therefore be realised that even thouqh a mixture may not contain sufficient ethane to ensure continued self-propaga-tion of flame part of the mixture may be burnt with a consequent development of pressure in a closed vessel. The earlier experiments with turbulent mixtures were made with the fan running a t 100 revolutions per second. The means of ignition was a secondary dischame (from a ' I 10-inch " X-ray coil) across a spark-gap of 12 mm.a t the centre of the sphere produced by breaking a current of 10 amperes in the primary circuit of the coil the trembler being locked. Such a dischayge is more thah adequate to ignite any inflammable mixture of ethane and air whe 84 WHEELER THE INFLAMMATION OF MIXTURES OF ETHANE AND the mixture is still yet it was found that no ignition or rather, no propagation of flame took place with a mixture of ethane and air containing as much as 3.2 per cent. of ethane when that mix-ture was agitated by the fan a t 100 revolutions per s p n d . On stopping the fan and allowing the turbulence to subside ignitim took place readily with complete inflammation of the mixture and the development of a pressure of 3.4 atmospheres.Similarly with mixtures containing 3-15 and 3.05 per cenb. of ethane no ignition could be obtained whilst the fan was running (at 100 revolutions per second) however frequently the discharge was passed although when the mixtures were free from turbulence ignition occurred on the first passage of the discharge. Details of these and similar experiments are as follow: Ethane in mixture. 3-20 Per cent. Result. No ignition when the fan was running a t 100 revolutions per sec. With the fan a t 40 revolutionsper sec. ignition took place a pressure of 4.5 atm. being recorded 0.25 sec. after ignition. Without the fan running a pressure of 3.4 atm. was developed. No ignition could be obtained when the fan was run-ning at 100 revolutions per sec.Without the fan ignition occurred at once a pressure of 3.2 atm. being recorded. With the fan at 40 revolutions per sec. ignition occurred on the fourth passage of the discharge. With the fan at 20 revolutions per sec. ignition occurred a t once. A pressure of 4.4 atm. was developed on both occasions, 0.177 sec. after ignition in the first experiment and 0.287 sec. after ignition in the second. No ignition could be obtained when the fan was run-ning at 100 revolutions per sec. Without the fan ignition occurred at once and a pressure of 2.8 atm. was recorded. No ignition with the fan a t 100 revolutions per sec. With 20 revolutions per sec. ignition occurred a t once and a pressure of 4.3 atm. was recorded 0.30 sec. after ignition.With the fan running a t 20 revolutions per sec. ignition occurred when the discharge was maintained (the trembler of the coil being in action). A pressure of 4.2 atm. was recorded. 3.15 3.10 3.05 3.00 2.95 Strong agitation of a mixture poor in combustible gas renders it difficult to ignite or t o be precise renders it difficult for the flame that no doubt occurs during the passage of the discharge to spread away therefrom and travel throughout the mixture. This difficulty increases as the degree of agitation is increased and as the prcenb age of combustible gas is decreased. When however the flame in such an agitated mixture does manage t o spread away from the source of ignition it travels rapidly. From the high pressure developed when a mixture was ignited that contained 2-95 per cent.of ethane and t o which turbulenc AIR IN A CLOSED VESSEL THE EFFECTS OF TURBULENCE. 85 had been imparted by a fan running a t 20 revolutions per second, it seemed that flame must have travelled through a greater propor-tion of the mixture than the one-third observed when the mixture was quiescent. An apparatus was therefore devised to enable the appearance of tho flames in turbulent mixtures to be examined. The apparatus which consisted essentially of a globe of glaea of about 4 litres capacity is shown in Fig. 1 and needs no descrip-tion. Preliminary experiments were made to determine the direc-tion of the air-currents induced by the fan which had two helical blades and revolved on a vertical axis. From the behaviour of coloured powders introduced into the globe while the fan was spinning it appeared that air was drawn from the centre of the globe towards the axis of the fan and was discharged a t the periphery of the latter as a spiral current directed obliquely* around the walls of the globe.Mixtures of methane and air were used for the experiments. Normally the lower-limit for central ignition of methaneair mix-tures in a closed sphere is 5.6 per cent. methane; the flame travels upward from the spark a t the centre until it occupies onethird of the vessel when it travels downwards as a horizontal disk to the bottom. The appearance of the flames in mixtures containing less than 5.6 per cent. of methane is shown in Big. 3 T. 1911 99, 2025. When a 5.6 per cent.mixture of methane and air was agitated by spinning the fan a t about 50 revolutions per second a succes-sion of discharges from an induction coil the trembler of which was in operation in the usual manner apparently failed to cause ignition. On close observation however it was seen that a pointed tongue of flame appeared a t each passage of the discharge directed dowrzwurds towards the axis of the fan apparently drawn thither by the current. The flame was ab40ut 2 cm. long and formed a sharp-pointed cone having the spark-gap (12 mm. in length) as its base. Occasionally if the discharge were maintained a fine fila-ment of dame darted rapidly over a distance of a few an. towards the fan. The speed of the fan was now reduced to about 30 revolu-tions per second and a discharge passed across the gap.The sequence of events was too rapid to be followed by the eye. It was observed that a downward-pointing tongue of Aame was produced as before and that this tongue after some hesitation shot towards the axis of the fan; the whole vessel then seemed to fill with flame and the glass was shattered into' powder. Further experiments were made with mixtures containing less methane. On two occasions the globe was shattered owing to the * No doubt owing to an unequal setting of the blades of the fan 86 WHEELER TEE INPLAMMATION OP MIXTURES 0.E gTHANE Am rapidity with which the mixture contained in it was inflamed but in a number of experiments notably in several with a mixture containing 5.0 per cent. of methane (see T. 1914 106 2595) the movement of the flame could be followed; or a t all events owing to the persistence of retinal impressions the course taken by the flame was apparent.An attempt has been made to indicate tho appearance of the flame to the eye a t a given instant by the shaded additions to Fig. 1. The impression produced can be described as that of a spiral whirlwind of flame the axis of the spiral being inclined a t an angle; in effect the flame seemed to follow the course of the current induced by the fan. It appeared alw that the flame passed several times through the mixture before i t finally died away a t the centre of the sphere. Analysis of the products of combustion of the 5.0 per cent. mixtures of methane and air showed that all the methane had been burnt.There can be little question as a result of these observations that the action of the form of turbulence studied in causing an enhanced speed of combustion of a weak inflammable mixture of methane or ethane and air within a closed vessel is purely mechanical. The flame which normally would be propagated mainly by conduction of heat from a burning t o an unburnt “layer” of mixture is forcibly dragged in the wake of the rapid current induced by the fan bcrning the mixture in its path. The difficulty experienced by the flame in sucli weak mixtures in travelling away from the source of ignition if the speed of the fan is very great is no doubt due to the fact that mixtures of the paraffins with air exhibit a considerable “ time-lag ” when the temperature of the source of heat that causes ignition is but little above the ignition-tempera-ture a condition obtaining with the flames of limit mixtures.With richer mixtures in which flame normally spreads a t an equal speed in all directions from the source of ignition the action of turbulence is mechanical also. To quote Mallard and Le Chate-lier (Zoc. cit. p.. 350) : “Lorsque le gaz dans lequel progresse la flamme est B 1’Btiit d’agitation la vitesse de propagation augmente parceque la chaleur se transmet non seulement en vertu de la conductibilit6 du melange gazeux mais encore en vertu des differences de vitesse des diverses parties de la masse. La surface de la flamme au lieu de garder une forme constante et rBguliSre se deforme ii chaque instant augmente de largeur en multipliant les points d’inflammation et par suite en rendant plus rapide la progression de la combustion.” If this explanation is correct it follows that (1) the greater the turbulence the more rapid should be the combustion; and (2) II'o face p .S AIR IN A CLOSED VESSEL THE EFPECTS OF !KJRBULENCE. 87 mixture in which the speed of flame normally is slow should be more susceptible t o the effects ,of turbulence than one in which the speed of flame normally is rapid. The first deduction has received experimental verification by Hopkinson whose results have already been quoted. His results are confirmed by a series of experiments in the 4-litre sphere with mixtures of ethane and air containing 3.85 per cent. of ethane, the timeipressure curves f o r which are reproduced in Fig.2. The time-intervals between ignition and the attainment of maximum pressure were mixture a t rest 0.146 sec.; fan running a t ( a ) 20 revs. per sec. 0.091; ( b ) 40 revs. per sec. 0.070 sec.; ( c ) 100 revs. per sec. 0.045 sec. Additional points that should be FIG. 2. 6 Time seconds. Time O=tiine of ignition. noted as regards these curves are (1) the slight increase of pres-sure obtained with the turbulent mixtures (a) and ( b ) and the marked increase with the turbulent mixture ( c ) as compared with that produced by the quiescent mixture; and (2) the disappearance from the curve fo,r turbulent mixture ( c ) of 'the1 horizontal portion a t maximum pressure noticeable in the other three curves. An explanation of these effects is offered later.I n order t o test the second deduction that should follow if the explanation suggested for the action of turbulence is correct two series of experiments were made with mixtures of ethane and air ranging between the lower-limit mixture and that giving the maxi-mum pressure on combustion. I n the one series the fan was run a t a constant speed of 100 revolutions per second; in the other th 88 WHEELER THE INFLAMMATION OF MIXTURES OE’ ETHANE AND Time seconds. Time O=time of ignition. Time seconds. Time O=time of igniton. * It should be noted that the unit of time employed in plotting the curves This contraction of t8he time- in Fig. 3 (and Fig. 2) is double that in Fig. 4. scale is rendered necessary from considerations of space AIR IN A CLOSED VESSEL THE EFFECTS OF TURBULENCE.89 turbdent mixtures occupying the left-hand portion of each diagram. From these curves the time that elapsed between ignition and the attainment of maximum pressure for each mixture can be deter-mined. These times together with the times for mixtures not included in Figs. 3 and 4 are recorded in the table that follows: Ethane in mix-ture. Per cent. 3.30 3.45 3.60 3-80 3-85 4-05 4.30 4.35 4-60 4-65 4.70 4.80 5.00 5.25 5.35 5-60 5.95 6.00 6.40 6-45 6-75 7-06 7.15 Time between ignition and the attainment of maximum pressure. Seconds. 7- Without With turbulence. turbulence. - 0.176 - 0.096 0-332 -0.152 -0-146 0.045 0-124 0.036 - 0-033 0.094 -- 0.026 0.073 -- 0.029 0.070 -0-063 0-024 - 0.021 0,064 0.020 0.052 - 0.019 0.0465 -- 0.019 0,046 -0.0466 0.019 0.050 0.020 0.082 -It has been shown (T.1918 113 852) that these time-inhrvals can be used to' calculate for each mixture the mean speed of propagation of flame between the' centre and the top of the sphere, a distance of 9.75 cm. The speeds thus calculated are shown plotted against percentages of ethane in Fig. 5. Allowing for the irregularities which are naturally more noticeable with the tur-bulent than with the quiescent mixtures the speeds for equivalent percentages of ethane in the two sets of experiments as deduced from the smoothed curves are given in'the table on p. 90. The conclusion that a mixture1 in which normally the speed of flame is slow should be affected by turbulence to a greater extent than one in which normally the s p e d of flame is rapid is thus proved experimeiitally by the gradual diminution in the value of the ratio B / A .Tk e DeveZoi~.rne~~t of Pressure.-On referring t o the time-pressure curves for mixtures without turbulence given in Figs. 3 and 4 an 90 WHEELER "HE INFLAMMATION OF MIXTURES OF ETHANE AND FIG. 5. comparing them with the curves for mixtures of methane and air previously published (Zoc. cit. Fig. 2 p. 847) i t will be seen that Mean Speed of Propgation of Flame f r o m C'etztre t o Top of Sphere. Cm. per see. Ethane in Without With mixture. turbulence. turbulence. Pep cent. ( A ) . (B). Ratio RIA. 3.6 35 142 4.06 3.8 55 195 3.54 4-0 75 237 3-17 4.2 95 2 84 2.99 4.4 112 320 2.85 4-6 129 360 2.79 4.8 144 400 2.77 5.0 158 430 2-72 5.2 172 462 2-68 5.4 185 485 2-62 5.6 195 500 2.56 5.8 202 510 2.52 6.0 210 518 2.47 6.5 212 518 2.44 6.7 200 495 2.47 both sets of curves are of the same type.All the mixtures o AIR IN A CLOSED VESSEL THE EFFECTS OF TURBULENCE. 91 ethane and air up to and including that containing 5.6 per cent. of ethane have time-pressure curves which exhibit the three stages of development noticeable with the mixtures of methane and air. The explanation of these stages offered when describing the methane curves can be applied also in the present instance, Support is given to the assumption then made that the second stage of development during which the recorded pressure remains constant represents a balance between a gradual decrease of pres-sure that begins as soon as inflammation 'sf the mixture is complete and is due to cooling by the walls of the vessel and an increase of pressure incident a t the same moment and due to the gradual attainment of thermal equilibrium.For it will be found that a graphical " correction " applied in conformity with this assump-tion in the manner described (Zoc. cit. p. 849) yields results for the maximum pressures in close agreement with the maxima recorded by equivalent mixtures when turbulent over the whole range from 3.80 per cent. ethane (at and above which percentage the flame travels from the centre in all directions a t the same speed) upwards . This is best shown in Fig.6 where the observed maximum pres-sures for all the mixtures experimented with both turbulent and quiescent and the " corrected '' maxima for the latter are shown plotted against percentages of ethane. It should be observed that the magnitude of the correction as is to be expected diminishes in proportion as the speed of inflammation of the mixture increases. Similarly the magnitude of the difference between the maximum pressures recorded with like mixtures when turbulent and quiescent also decreases as the speed of inflammation of the latter increases, until with mixtures containing mom than 5.6 per cent. of ethane no difference is observable between the two sets of pressures. Further the crests of the time-pressure curves for the quiescent mixtures that contain more! than 5.6 per cent.of ethane no longer remain hori-zontal over a measurabl'e length of time but the cooling curves begin as soon as the maxima are attained. Pier (Zeitsch. Elektrochem. 1909 15 536) who used the pres-sures developed by the inflammation of different mixtures in a closed veasel to determine the specific heats of various gases has made observations which have a bearing on the question of the effecta of turbulence. Using a manometer of similar construction t o the Petavel gauge (Phil. Mag. 1902 [vi] 3,461) Pier found exact agreement between the observed and the calculated pressures produced by mixtures the combustion-temperatures Qf which exceeded 1 6 0 0 O . For this reason he combatted Nagel's opinion ((' Versuche uber Zundgeschwindig 92 WHEELER THE INFLAMMATION OF MIXTURES OF ETHANE AND heit explosibler Gasgemische,” Mit teilungen iiber Forschungs-arbeiten des Zngelzieurwesem Vo,l.54 1908) that with central igni-tion in a spherical vessel the mixture near the walls must be raised in temperature by adiabatic compression before flame reaches i t FIG. 6. I ‘7 / ‘ I c, P‘c 0% 0 o x 0 1 I / I -2-5 3 4 5 6 7 7 Ethane per cent. Quiescent observed x , corrected Turbulent observed @ (an opinion that had already received experimental verification by Hopkinson) and suggested that the interchange of heat between different portions of the mixkxre within blie vessel must be practi-cally in&antaneous AJB IN A CLOSED VESSEL THE EBFECTS 02’ TURBULENCE. 83 This result Pier supposed would be effected by a rapid whirling and mixing of the contents of a spherical vessel owing to a sudden increase of pressure on ignition a t the centre.It is clear if only by reason of the difference observable in the character of the time-pressure curves for ethane-air mixtures with and without arti-ficially-produced turbulence that Pier’s contention cannot be cor-rect; and Hopkinson’s measurements of the temperatures within a closed cylindrical vessel a t the moment of maximum pressure pro-duced by the inflammation of a mixture of coal-gas and air (Proc. Roy. SOC. 1906 [A] 77 387) should have convinced Pier of its falsity. . I n the absence of knowledge regarding the composition of the products of combustion a t the moment of attainment of maximum pressure when the ethane-air mixtures contain excess of ethane it is not possible to calculate the theoretical pressures that should be given by such mixtures on ignition in a closed sphere were there no loss of heat during the propagation of flame.Calculation can, however be made for those mixtures in which the combustion of ethane can be presumed to be complete. The mixture of ethane with air in which ethane and oxygen are in the theoretical propor-tions for complete combustion to form carbon dioxide and steam contains 5-63 per cent. of ethane. The dotted line in Fig. 6 repre-sents the calculated maximum pressurm mer the range 3-8-5.5 per cent. ethane.* It will be seen that a loss of heat of between 9 and 12 per cent. presumably due to radiation during the propagation of flame is indicated.A matteq for further study is the fact that the mixtures of ethane and air which produce the highest pressuretj are not those within close range of the mixture containing ethane and oxygen in theo-retical proportions for complete combustion (5.63 per cent. of ethane) but lie over a considerably higher range namely 6.5-7-0 per cent. The time taken for the attainment of maximum pressure reaches a minimum over the same range or in other words the speed of propagation of flame under the conditions of the experi-ments is fastest in mixtures containing between 6.5 and 7.0 per cent. of ethane. I n this respect the results obtained with mix-tures of ethane and air differ markedly from those with methane and air. Further comparison of these results with those obtained with mixtures of methane and air is reserved for a future communica-tion which will include the results of similar experiments with other n embers of the paraffin series of hydrocarbons. * The cdculations were made in the manner described in T. 1918,113, 868 using Langen’s values for the specific heats of the gases 94 MORGAN THE IGNITION OF EXPLOSIVE E x P E R I M E N TAL. The apparatus used (Clitre sphere) and general method of pro-cedure f o r the experiments has already been described (Zoc. cit., p. 854). The ehane was prepared by the action of water on zinc ethyl and was purified by liquefaction by liquid air; the ratio C I A on explcsion analysis was 1-25 showing that it contained no impurity. The majority of the experiments described in this paper were carried out during the year 1912 with the assistance of Mr. M. J. Burgess. [Received November lBth 1918.

ISSN:0368-1645    

DOI:10.1039/CT9191500081

出版商:RSC    

年代:1919

数据来源: RSC