摘要:

CONSTITUTION OF THE METHYL PENTOSES. PART I. 73X.-A Conti-ibutiorz to the Study oj' the Constitutionof the Merhyl! Peiltoses. Port I. Synthesisof an i-Methyl Tetrose und an i-&fethyl Tct7itol.By ROBERT GILMOUR.THE exact constitution of the known members of the methyl pentoseseries has not been fully established as yet, except in the cases ofrhamnose and isorhamnose, the configurations of which haverecently been determined by Fischer (Bey., 1912, 45, 3761). In theremaining members a doubt exists as to the position of thehydroxyl group contiguous to the methyl group. It seemed, there-fore, of some importance to attempt the synthesis of active methyltetroses of known constitution from which methyl pentoses mightbe prepared. The importance of the subject seemed enhanced bythe fact that the active methyl tetroses might be made to serveas standards with which the degradation products of the naturallyoccurring methyl pentoses could be compared, and thus enable theirexact configuration to be determined.The most suitable starting material appeared to be the dihydroxy-valerolactone, which Thiele obtained by oxidising Aha-angelicalactonewith potassium permanganate (AnnaJen, 1902, 319, 194) and con-sidered to possess the structure :0CW;&H *(:El (OH).C'H (OH).hO.On reducing this compound with sodium amalgam in the usualway a solution was obtained which contained an amount of reducingsugar equivalent to 6 per cent. of the lactone used, and as theresult of some twenty experiments this was found to be themaximum yield of sugar in any one reduction.A series of quantitative experiments was carried out with theobject of tracing the exact course of the reduction.I n each casethe unaltered lactone was separated from the syrupy reductionproduct and weighed, and the amount of sugar present in the reduc-tion product was estimated by titration with Fehling's solution..___-The result^ of three experiments were as follows:TotalLactone Sodium Lactone reduction Per cent.grams. grams. grams. grams. granis. lactone.used, amalgam, recovered, product, Sugar, of(1) . 28 250 16.5 10 containing 1.6 = 5 . 7160 11.0 4'8 ,, 1.0 = 6.0 1;; ;l":o" 200 5.7 4.5 ,, 0.7 = 6-8It will be seen that the percentage of sugar formed remain'14 GILMOUR: A CONTRTBUTION TO THE STUDY OF THEconstant.This pointed t o the fact that the reduction was proceed-ing too far, and that the sugar-alcohol was being formed from thesugar almost as quickly as the latter from the lactone, and thiswas found to be the case as the product proved to be mainly sugar-alcohol.From the reduction product an osazone was isolated which provedto be a methyl tetrosazone melting a t 140-142O. Similarly, bytreatment with phenylbenzylhydrazine in alcoholic solution a methyltetrosep?knylb enzylhydrazone melting at 99-looo was obtained.From the aqueous solution from the preparation of the hydrazonea methyl tetritol was isolated as a yellow spup. On benzoylatingthe latter a tetrabenzoylmethyltetm'tol melting a t 136-137O wasobtained.The methyl tetrose was obtained in the free state by decomposingthe phenylbenzylhydrazone with formaldehyde.It proved to be apale yellow, strongly reducing syrup. As the yield of pure sugarwas very small, amounting to only 3 per cent. of the lactoneused, an attempt was made to obtain an additional quantity of itby oxidising the methyl tetritol with Fenton's reagent. In thisway a small amount of the sugar was isolated as its phenylbenzyl-hydrazone.Dimet?~ox~vaZeroZacton~e has also been obtained by methylatingdihydroxyvalerolactone. It melts at 59-60O. An attempt wasmade to reduce the methylated lactone, but without success.The constitution of the methyl tetrose described has not beenestablished yet, but it must be represented by either formula (I)or (11), according to the positions assumed by the hydroxyl groupsduring the oxidation of Aa-angelicalactone.The yield was, however, very poor.FHO YHOA study of the methyl tetronic acids obtainable from methylglycerose is being undertaken with a view to settle the question ofthe constitution of the tetrose described.EXPERIMENTAL.AB-A rtgelicdactoite.The method followed in the preparation of this compound wasAs, however, the preparation was that due to Thiele (Zoc.cit.)CONSTITUTION OF THE METHYL PENTOSES. PART I. '75on a very much larger scale, and differed in one or two particulars,i t may with advantage be described.Two hundred and fifty grams of commercial lmmlic acid wereadded t o 300 grams of acetic anhydride, and the mixture was heatedto looo during six hours.The product was then distilled under apressure of 300 rnm., and the distillate collected in four approxi-mately equal fractions. The first fraction consisted entirely ofacetic acid, the others of acetic acid with increasing amounts ofAD-angelicalactone. Each fraction as it distilled over was immedi-ately neutralised with sodium carbonate, and the oily layerextracted with ether. (ThieIe recommends fractionation of thedistillate at a low pressure as the best means of removing the aceticacid, but in this case a quantity of acetyl-lzevulic acid is invariablyformed, which materially decreases the yield of AB-angelicalactone.Indeed, if the acid distillatm are allowed t o remain for any timewithout neutralising, reversion to acetyl-laevulic acid t.akes place toa large extent.) The combined ethereal extracts were dried, theether distilled off, and the lactone fractionated under 15 mm.pres-sure. It distilled almost completely between 6 4 O and 70°/15 mm.,and consisted of approximately pure AB-angelicalactone.I n all, 2 kilograms of lmmlic acid were worked up, and a totalyield of 1100 grams (70 per cent. of the theoretical) of AB-angelica-lactone was obtained.Conversion of AB- into A-Angelicalactone.From 1100 grams ofthe AB-lactone 835 grams of Pa-angelicalactone were obtained in apure condition.Thiele's method was employed (loc. cit.).Oxidation of Aa-Angelicdactone.The method employed was ewentially that of ThieIe (loc.cit.).In all, 820 grams of Aa-angelicalactone were oxidiaed; the totalyield of crude material being 170 grama, from which, on crystallia-ing from ethyl acetate, 160 grams of the pure product melting atlooo were obtained. This amounts to about 17 per cent. of thetheoretical yield.Reduction of aS-DiiEydroxyvaZeTolac tone.Ten grams of the lactone were dissolved in 100 C.C. of water, andthe solution was acidified with 20 per cent. sulphuric acid. Thesolution was then cooled to -5O, and 100 grams of 24 per cent.sodium amalgam were added in five portions, with continual vigor-ous shaking, and addition from time to time of 20 per cent76 GILMOUR: A CONTRIBUTION TO THE STUDY OF THEsulphuric acid in portions of 2 C.C. (5 C.C. €or each of the first four20 gram-portions of amalgam and 3 C.C.for the last portion).The solution was rendered faintly acid to Congo-red paper, andtested with Fehling’s solution. One volume waa found to reducetwo volumes of the solution.The aqueous solution was now concentrated as far as possibleon the Fater-bath. The residue was extracted several times withhot alcohol, and the extract filtered from sodium sulphate andcomelitrated to a syrup on the water-bath. The syrup was foundto have only a slight reducing action on Fehling’s solution. How-ever, after boiling with dilute hydrochloric acid, a vigorous reduc-tion was obtained, which justifies the conclusion that a compoundof the nature of an acetal or alcoholate had been formed duringthe extraction with alcohol.The syrup (9.5 grams) crystallisedalmost completely on nucleating with the lactone. The process wasthen repeated on the product, the sugar formed being protectedfrom further reduction by the fact that it had been convertedinto an alcoholate or acetal, or possibly glucoside. The second,third, and fourth reductions were carried out with 55 grams ofsodium amalgam, and the fifth with 50 grams of amalgam. Thesyrupy product now weighed 7 grams, and showed no signs ofcrystallisation on nucleation with the lactone, and very little actionon Fehling’s solution. On titration with baryta it was found stillto contain about 5 per cent. of unaltered lactone.Hydrolysis of the Methyl Tetrose (Acetal) 9The syrup (7 grams) wits boiled with 60 C.C.of 5 per cent. hydro-chloric acid for half an hour. The acid was removed with bariumcarbonate, and the filtrate decolorised with animal charcoal, andconcentrated in a vacuum at 4 5 O to dryness. The residue waOextracted three times with boiling alcohol, and the extract concen-trated in a vacuum a t 35O to a syrup. The product was a yellowsyrup, and weighed 5 grams.0.116 Gram of the syrup reduced 2 C.C. of standard Fehling’ssolution, which gives 10 per cent. as the sugar content of thesyrup (calculated as dextrose).Methyl T e trosazone.Two grams of the syrup prepared as above were mixed with1 gram of phenylhydrazine, 1 C.C. of 60 per cent. acetic acid, and2 C.C. of water. The mixture was heated on the water-bath foran hour, when the osazone separated as a black oil.After somehours the mother liquor was poured off, and the oil dissolved iCONSTITUTION OF TEE METHYL PENTOSES. PART 1. 77alcohol. About twenty volumes of water were added to the alcoholicsolution, which was then allowed to remain overnight. The osazoneseparated as a flocculent, yellow precipitate, which wm collected,dissolved in alcohol, and again precipitated with water. Thecompound ~7as then collected and dried in a vacuum, the yieldbeing 0.2 gram.The analytical figures obtained showed that it was still impure;consequently it was still further purified by dissolving the remainder(0.1 gram) in a very small quantity of a mixture of alcohol andether, t o which 100 C.C. of light petroleum were then added. Afterremaining for some time with occasional stirring the osazoneseparated suddenly as a pale yellow, microcrystalline precipitate.It was collected, washed with light petroleum, and dried in avacuum.The compound forms yellow, microcrystalline needles,very sparingly soluble in water or ether; but readily so in alcohol,and melts at 140-142O:O.OG52 gave' 0.1652 CO, and 0-0408 H,O. C= 66.05 ; H = 6.69.C,,H,,O,N, requires C = 65-38 ; €€= 6-41 per cent,As the yields of sugar by this method were still far from satis-factory a further variation of the method of reduction was adopted,which obviated any risk of the methyl tetrose alcoholate or acetalbeing further reduced by the action of sodium amalgam in acidsolution.Twenty-eight grams of dihydroxyvalerolactone were dissolved in270 C.C.of water, acidified with 20 per cent. sulphuric acid, andreduced with 250 grams of 24 per cent. sodium amalgam in fiveportions, exactly as in the experiment previously described. (Onevolume of the resulting solution reduced one volume of Fehling'ssolution. Volume of solution= 340 c.c., therefore sugar in solu-tion=1-6 grams, o r 5.7 per cent. of lactone used.)The solution was worked up as usual. and the product separatedfrom sodium sulphate by extraction with alcohol. The solvent wasremoved at 35O,/15 mm. The product was a crystalline mass ofunchanged lactone mixed with Byrupy material, which was quiteinsoluble in ether. The material was treated with a mixture ofethyl acetate and ethyl alcohol (3:1), which dissolved the syrup,but very little of the crystallins lactone.After removing the latter,the filtrate was again concentrated, and the process repeated threetimes. In this way the lactone was almost completely separated,the total amount recovered being 16.5 grams. The filtrate wasconcentrated, and the residual syrup was dried in a vacuum. Itweighed 10 grams.A second reduction wit^ carried out on the 16.5 grams of recoveredlactone. One hundred and sixty grams of amalgam were used, a 78 GlLMOUR: A CONTRIBUTfOK TO TBE STVDY OF 'IHEthe solution obtained reduced 1.1 volumes of Fehling's solution.(Solution = 190 c.c., therefore sugar = 1 gram = 6 per cent. oflactone.)On working up, 11 grams of lactone were recovered, and thesyrup remaining weighed 4.8 grams.The 11 grams of recovered lactone were treated as before with200 grams of amalgam. (Sugar formed=0'7 gram=6.3 per cent.of lactone.) Lactone recovered = 5.7 grams ; syrup recovered =4*5grams.The combined syrups (19 grams) were hydrolysed as usual with5 per cent.hydrochloric acid, and the product, which weighed15 grams, was found to contain 2'5 grams of sugar (estimated asdextrose).Seventy grams of dihydroxyvalerolactone were worked up in asimilar manner, and the resulting 50 grams of syrup hydrolysed.Net h yl Tetrosephenylb entylhydrazone.The combined syrups from reduction experiments (60 grams)were dissolved in 200 C.C. of absolute alcohol, and 10 grams ofphenylbenzylhydrazine were added. After heating on the water-bath for tweiitIy minutes water was added, which precipitated thehydrazone as a brown oil.This was dissolved in benzene, and onallowing the benzene to evaporate spontaneously the hydrazoneremained as a sticky, brown, crystalline mass. It was washedseveral times with cold benzene, and recrystallised from a largeamount of boiling water, the yield being 6.5 grams. The compoundforms fine, colourless needles, is readily soluble in benzene, ether,or alcohol, but only very sparingly so in cold water, and melts a t99-1ooo :0.1199 gave 0.3012 C02 and 0.0746 H,O. C=68-51; H=6*95.0.1838 ,, 14.5 C.C. N, at 17O and 748 mm. N=9.10.C18H2203N2 requires C= 68.78 ; H = 7-00 ; N = 8-91 per cent.Methyl Tetritol.The aqueous solution from the above hydrazone preparation wasextracted thoroughly with ether in order to remove any excess ofphenylbenzylhydrazine or hydrazone, and concentrated a t 55O /33 mm.to a syrup. Alcohol was added, and some barium chloridewhich was precipitated was removed. The filtrate was then concen-trated, and the residue dried over sulphuric acid in a vacuum; theyield was 40 grams.Methyl tetritol so obtained forms a yellow syrup, which does notreduce Fehling's solution. It is readily soluble in water or alcohol,but insoluble in ethyl acetate or ether. It was not in a sufficientlCONSTIT'UTION OF THE METHYL PENTOSES. PdElT I. 79pure state for analysis, but was identified by the formation of itst e trabenzoyl derivative.Tetrab enzoylmethyltetritol.Two grams of the syrup were mixed with 14 grams (7 mols.) ofbenzoyl chloride and 100 C.C.of 2X-sodium carbonate solution. Thereaction was carried out. in the usual manner, and the gummy,caoutchouc-like product was washed with sodium carbonate andwater, and dissolved in ether. The ethereal solution, after beingdried, was allowed to evaporate spontaneously. A sticky, crystallinemass was obtained, which was rubbed with alcohol until quitecrisp, collected, and recrystallised twice from absolute ethyl alcohol.Tetrab enzoylmethyltetritol crystallises in hard, colourless, prismaticneedles, which are readily soluble in ether, moderately so in boilingabsolute ethyl alcohol, but very sparingly so in the cold, andinsoluble in water. It melts at 136-137O:0,1560 gave 0.4094 GO, and 0-0736 H,O.C=71*60; H=5.27.C,H,O, requireg C=71.73; H=5.07 per cent.Methyl Tetrose.4.5 Grams of the phenylbenzylhydrazone were heated on thewater-bath with 10 C.C. of 40 per cent. formaldehyde in about80 C.C. of water. After two hours' heating the formaldehydephenyl-benzylhydrazone which had separated was removed by extractionwith ether. The aqueous solution was then concentrated at 35O/30 mm. to a syrup, water was added, and the solution again concen-trated, the process being continued until no odour of formaldehydecould be detected in the product. The tetrose was obtained as aviscid, pale yellow syrup, which could not be crystallised; the yieldwas 1 gram. The substance is readily soluble in water or absolutealcohol, and reduces Fehling's solution vigorously.After drying at 60°/50 mm.for several hours the substance wasanalysed :0.1405 gave 0.2301 CO, and 0.0932 H,O. C=44.65; Ei=7*42.C5HloO, requires C = 44-77 ; H = 7.46 per cent.Oxidatiorc of Methyl Tetm'tol.Ten grains of the methyl tet'ritol were dissolved in 60 C.C. of water,and a solution of 2.5 grams of ferrous sulphate in a few C.C. ofwater was added. Sixty C.C. of hydrogen peroxide (3 per cent.)were then added slowly. The temperature of the mixture rose toabout 40°. After some hours the solution was shaken with bariumcarbonate, filtered, and concentrated in a vacuum to a syrup.The product was treated with 2.5 grams of phenylbenzyl80 CONSTITUTION O F THE METHYL PENTOSES. PART I.hydrazine in the manner previously described, and the hydrazoneseparated by extraction with benzene.A red syrup was obtained,which partly crystallised. After washing the crystalline matterwith benzene, and recrystallising from hot water, the phenylbenzyl-hydrazone of the methyl tetrose was obtained, and identified by itsmelting point, 99-looo. The yield was, however, very small.a& Dim e t .32 o x y vale r olac tone .Two grams of dihydroxyvalerolactone (1 mol.) were dissolved in8.6 grams of methyl iodide (4 mols.). To the solution 7 grams ofdry silver oxide (2 mols.) were added, and the mixture was heatedon the water-bath for five hours. Ether waB then added, and thesilver residues were removed. On evaporation of the ether theproduct crystallised a t once.After recrystallising from a mixtureof acetone and ether it was obtained pure. It crystallises in hard,colourless prisms, which melt a t 59-60°:0.1982 gave 0.3792 CO, and 0.1312 H,O. C=52*22; H=7.40.C7H,,0, requires @= 52-50 ; H = 7.05 per cent.An attempt was made to reduce the methylated lactone in theusual way, but the resulting solution had no action on Fehling'ssolution, so evidently no reduction takes place. The solution wasneutralised with sodium carbonate, evaporated to dryness, and theresidue extracted with alcohol. The alcoholic extract on evapor%tion left a residue of sodium y-hydroxy-a~-dimethoxyvat?eric acid :0.0774 gave 0.0278 Na,SO,. Na= 11.62.C7HI3O,Na requires Na= 11.50 per cent.Brucine Salt of Methyl Tetronic Acid.Attempts were made to effect a resolution of the dihydroxy-valerolactone by means of brucine.The brucine salts of the d- andZ-forms of the acid unfortunately form a partially racemic com-pound, which cannot be resolved by crystallisation, and has theconstant specific rotatory power [a]:' - 29'6O.Proof that the salt is coniposed of one molecule of the d-saltand one molecule of the 2-salt is afforded by the fact that therotation of the solution obtained by boiling a solution containingone equivalent of lactone and one equivalent of brucine, is almostexactly the same, namely, [a]: -29'2O.The sctlt crystallises in fine needles, which are very soluble inwater, but only sparingly so in absolute alcohol, even at theboiling point. It melts at 180-181O:0.2335 gave 0.5256 CO, and 0.1374 H20. C=61*41; H=6.58.C,H1006,C23H3604N2 requires C = 61.76 ; H= 6-61 per centTHE ROTATORY~DISPEKSIVE-POWER OF ORGANIC COMPOUNDS. 8 II n conclusion, I desire to thank Professor J. C. Irvine for theinterest which he has taken in this work. I have also to thankDr. H. J. H. Fenton, of Cambridge, for the experimental detailsof his method of oxidising sugar alcohols; Professor Letts forextending to me the hospitality of his laboratory during the finalstages of this work; and the Carnegie Trust for a research grantwhich partly defrayed the expenses of the investigation.CHEMICAL RESEARCH LABOKATOKY,UNII‘ED COLLEGE OF d ~ . SALVATOR AND ST. LEONARD,UNIVERSITY OF ST, ANDREWS.THE S I R DONALD CUltBIE LAl:ORATOItIES,QUEEN’S UNIVERSITY, ~~J:LF-AS’I-

ISSN:0368-1645    

DOI:10.1039/CT9140500073

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

THE ROTATORY~DISPEKSIVE-POWER OF ORGANIC COMPOUNDS. 8 IXI. - The, Rotatoy-y Dispersive Powei* of O~gtv&Compounds. Part I V. Magnetic Rotation a dDispersion, in Some Simple Organic Liquids.By THOMAS MARTIN LOWRY.IN Perkin’s classical experiments “ On the Magnetic RotatoryPolarisation of Compounds in Relation to their Chemical Constitu-tion ” (T., 1884, 45, 421) and “On Magnetic Rotatory Power,especially of Aromatic Compounds” (T., 1896, 69, 1025) nearlyall the measurements were made with sodium light. A few experi-ments were made with thallium and lithium, but, for the mostpart, attention was concentrated on an incessant comparison of therotation produced by the substance with that produced in lightof the same colour by an equal column of water. In many casesten or twelve independent values were obtained for the molecularrotation in a given compound, with the result that, although theangular deflexion of the plane of polarisation was only about loo,Perkin was able to record, in one series of fatty compounds afteranother, a difference between observed and calculated valuesamounting on the average to less than 1 part in 1000, or barelyO - O l O on the angular readings.The experiments now described were undertaken with the objectof determining the extent to which the magnetic rotatory powerof the simpler organic compounds is influenced by varying thewave-length of the light.The comparison of the actual magnitudeof the rotations with those produced in an equal column of waterwas merely incidental to the main object of the research, and noattempt was made to cover a second time the ground which hadbeen so effectively cultivated by Perkin. Attention was directedinstead, first, to a careful investigation of the form of the curveVOL.cv. 82 LOWRY : THE ROTATORY .DISPERSIVE POWER OFof rotatory dispersion (Part 11); secondly, to the measurement ofthe dispersion-ratios for a large number of simple organic liquids(Part IV); and thirdly, to a comparison of the natural andmagnetic rotatory dispersions in a series of optically active liquids(see the following paper, Part V, of the series).The observations now described were spread over a period ofabout six years, and include a number of the early pioneeringexperiments. The ‘‘ water-ratios ” (Perkin’s (‘ specific rotations ”)for green mercury light were recorded in every case to 1 part inlOOU, but certain small inequalities in the experimental conditionswere discovered, which rendered the last figure in these ratios some-what uncertain.When, therefore, it was discovered, almost a t theclose of the investigation,( a ) that the variation of magnetic rotatory power with wave-length could be expressed by an equation, a = k / (A2 - Ao2), involvingonly two arbitrary constants, and consequently( b ) that the rotation and dispersion effects could be separatedboth easily and completely,it was evident that more trustworthy values for the ‘(absolutemolecular rotations” could be obtained by taking, as a basis forthe comparison with water, Perkin’s readings for yellow sodiumlight rather than the new readings for green mercury light.In thepresent paper, therefore, a series of “ absolute molecular rotations ”has been worked out to three places of decimals from Perkin’s“ water-ratios ’’ and the new “ dispersion constants ” ; correspond-ing values derived from the new “water-ratios” for mercury lightare given as approximations to two decimals only..Rotatory Dispemion in Homologous Series.One of the most striking results of the present investigation hasbeen to show the remarkable constancy of the magnetic rotatorydispersion in homologous series, when once the earlier homologueshave been passed; thus, selecting figures from the general tables,find the following series of steady values: weTwo paraffins .....................Three primary alcohols .........Nine methyl-alkyl -carbinols ...Four methyl ,, ketones ...Four isoyropyl ,, ,, ...Six fatty acids .....................Seven esters .....................Five ethyl ,, 9 , ‘ * *Six .isopropyl ,, ,? ---c, to c,c4 t o c,c, to C,Z c, to c,,c, to c,, c, to c,c‘, t o c,,c, to c5 c, t o c5Dispersion->rdtio,1’6351.6361 %372’6321.635%3sY/ab161*;::&1’6341’631The averages for 44 substances are .........1 *635Dispersivepower,1.951.982.011 . 8 i1.952.071’961-931’841-95looh:.ORGANIC COMPOUNDS. PART IV. 53Ethgl ,, ,, :..... 1'683isoPropy1 ,, ,, ...... 1.635Ethylaiid propylnlkgl kctoms 1.652isoE'iop;l alkyl kctorits .........1 63584 LOWRY: THE ROTATORY DISPERSIVE POWER O Fvalues are obtained for the magnetic rotatory power of the acidstha.n of the isomeric esters of the same series.Analogous deviations from the average are observed on compar-ing the dispersion ratios of the lowest homologuB with those of thehigher members of the sa-me series. As a general rule the lowestmembers show an abnormally high dispersive power; thus, oncomparing whole series of lower homologues with series of higherhomologues, we have :Acids ...........................Dial ky lcarbinols ...............{Esters ...........................Meth ylallrylcarbinols .........Methyl alkyl ketones .........Dialkyl ketones ...............Methyl formate { ,, esters ..................i ...............R*CO,H ..............R'CO,'CH,, etc. ......R*CH(OH)*CH, ......TI.'CH(O H )'C,H,, CLC.R.=CO*CH, ............R'CO TzH,, etc. ......H*CO;cH, ..........CH,*CO,*CN,, etc. ...16341-5311.63716841-6391 -6381 -6371 .GS 1Amongst the primary alcohols the high value for the dispersion-ratio of water is followed by low values for the next homologues,thus :Molecular rotation.Disyersioiz- f .ratio. Observed. Calculated.H*OH ............... 1.645 1 *ooo 0.699CH,*OH ............ 1 '629 1'640 1'72.2C,H,*O H ............ 1,631 2.7ao 2.745C,H,*OH ........... 1 -634 3.768 3-768C,H;OH, etc. ... 1 -636 0'699 + 1.023i~These low values are not so pronounced as in the very earlyobservations quoted in Part 11, p.1072, but they have been checkedrepeatedly, and there can be no doubt as to their real existence.They are confirmed by Perkin's observation (which is corroboratedby the new measurements now recorded) that whilst themolecular rotations from propyl alcohol upwards form a regulararithmetical progression, the first three homologues show themarked abnormality which appears in the third column of thepreceding table. In particular it may be noticed that both themolecular rotation and the rotatory dispersion are abnormally highin the case of water, and abnormally low in the caae of methylalcohol; the rotation and dispersion in ethyl alcohol are onlyslightly abnormal, but in opposite directions.Branching the chain of carbon atoms, which Perkin found t oincrease the magnetic rotatory power of many series of compounds,may sometimes produce an increase of rotatory dispersion.But tothis rule there are very many exceptions ; thus we have ORGANIC COMPOUNDS. PART IV. 85Dispersion-mt ios.{Butyl alcohol.. ......................... 1'637Nine methyl-alkyl-carbinols ...... 1~33:Six isoPropyl ,, , , ...... 1.635..................... (isoButy1 alcohol 1.635Bntyric acid 1 *63 4isoBur yric acid 1'633.................................................. {{The following series are, however, instructive :Methyl alcohol ..............Ethyl ,, ...............isoPro py 1 , , ...............lert. . h t y l , , ..............Acetone .......................Methyl ethyl ketone , , , .. ,Pinacolin .....................isoPropy1 alcohol ............scc.-Butyl ,, ............Methylisopropylcnrbinol ...Methyltert. -butylcarbinol . .Dispersion-ratios.CH, '0 H ............... 1,629C H,Me'OH., .......... 1'631C 11 e3 . 0 H ............ 1-645CH3'CO'CH,Me ... 1'638C€I,*CH(OH)*CHh~e 1.636CH;CH(OH)'CHMe, 1'641CH,'CH(OH) 'CMe, . 1 '643CH \Ie,'OH ............ 1'634CH,*CO-CH, ......... 1'638CH,*CO 'CMe, ...... 1.640CH,*CH(OH).CH,.., 1 '634I n each of these cases the introduction of the tert.-butyl groupbrings the dispersion-ratio up to or above 1.640.Absolute Moleculcrr Magnetic Rotation.I n working out his observations, Perkin adopted the very con-venient plan of using water as a basis for comparison, instead ofworking out the " Verdet constant," which measures the absolutemagnitude of the effect produced in unit magnetic field.The directobservations consisted in every case in a comparison of the rota-tions produced by equal columns of the substance and of waterwhen placed in the same magnetic field; the ratio of the tworotations (our " water-ratio ") was called by Perkin the (( specificrotation " of the substance. In Perkin's experiments the compari-son was made with water a t the same temperature as the liquid;this condition also prevailed in our experiments, as all readingswere taken a t 20°.The first step in calculating out the results of the observation isto divide the "specific rotation," that is, the ratio of the tworotations, by the ratio of the two densities.The comparison is thenbetween equal masses of the two liquids instead of between equallengths or volumes. If the rotation produced by a given columnof water were always proportional to its density, its temperaturewould be a matter of indifference. But as the ratio of rotation todensity is not constant, but increases with rising temperature (tothe extent of 0.8 per cent. between Oo and looo), it is necessaryin exact work to select a standard temperature for the water, forexample, 4O. The ratio of rotation to density is, however, exactlythe same at Oo and 20°, and differs only by 1 part in 10,000 whe86 LOWRY: THE ROTATORY DISPERSIVE POWER OFa comparison is made between 4O and 20°; the correction is there-fore only important when hot water is used as a basis of comparisonfor a hot substance, and does not introduce any perceptible error inmeasurements made at 2 5 O or below.The second step is to calculate the “molecular rotation” bymultiplying the preceding ratio by the ratio of the molecularweights of the substance and of water, 60 that:a,, ( i s Jft”~ 0 1 .rotn, = ‘ 8 x !7~’ x _A’/. ,where a, aw are the two rotations,d, d,,, ,, ,, ,, densities,N8 Mw ,, ,, ,, molecular weights.I n Perkin’s work the molecular weight of water was taken as 18,but the introduction of the modern value 18.016 does not &ectthe result, as the ratio of the molecular weights has not beenaltered to any marked extent. By this- further reduction a com-parison is made of the effects produced by equal numbers ofmolecules of the substance and of water.The final step is to eliminate the influence of the wave-length ofthe light.This is done by calculating the rotations which wouldbe produced when using light of wave-length given by the equationhs==l+%2 f o r the substance and for water respectively. Therelationship takes the following form :A2 - A,2A2- x,,2Absolute molecular rotation= Mol. rotn. x ___-where h = 0.5893 or 0.5461, according as the “specific rotation ” wasdetermined with sodium light or with green mercury light, andh,? and hw2 are the ‘( dispersion constants” of the substance and ofwater respectively.It is perhaps fortunate that water, in spite of its many abnormali-ties, does not differ very widely in dispersive power from the simpleorganic compounds of the fatty series.The reduction to ‘‘ absolute ”rotations, which is necessary in order to eliminate the effects ofcolour and of dispersion, does not involve any very large alterationin the relative values recorded for sodium or for mercury light.Taking the dispersion-ratio for water as 1.645 (dispersion-constantA,:!= 0’0222) and the dispersion-ratio for the fatty compounds as1.635 (dispersion-constant h02= 0*0195), the effect of reducing theobservations to “ absolute rotations’’ is to increase the values forsodium light by about 0.7 per cent. and the values for mercurylight by about 0.9 per centORGANIC COMPOUNDS. PART 1V. 87I n the case of aromatic compounds, having a much higherdispersive power than water, the molecular rotations would besubstantially decreased by reducing to “ absolute ” wave-lengths.Thus, in the case of a substance having the dispersion-ratio 1.735(dispersion constant h,2= 0.0427) the molecular rotations for sodiumlight would be decreased by 7 per cent., and those for mercury lightby 9 per cent.!A bsohcte Molecular Rotatiorb in Homologow Series.Perkin found bhat the molecular rotation for sodium lightincreased in a very regular way by increments of 1-023 in homo-logous series of fatty compounds.The molecular rotatione couldtherefore be expressed by the formula:S IMol. rotn. = 8 + 1*023.n,where s is the ((series-constant” and n is the number of carbonatoms in the molecule (T., 1884, 45, 574).This formula had to beabandoned in the case of the lowest members of each series. It wasalso necessary to assume special values for the series-constanb ofthe acids and methyl esters in place of the general value for thehomologous alkyl esters and for the formates and acetates in placeof the general value for the esters of thehigher acids of the seriee.With less justification, special values were also assumed for theseries-constants of all iso-compounds, including the fatty acids,although the figures for butyric and isobutyric acids were foundto agree closely with one another.When these limitations are accepted a very remarkableuniformity appears in the increments for different homologousseries, the observed and calculated values agreeing, as a rule, within1 part in 1000.It will be evident that so close a concordancecould scarcely have appeared if the series had differed a t all widelyin dispersive power; an exact agreement could then have beenobserved only for one wavelength, and it is unlikely that thiswould have been the wavelength of sodium light. It is indeedonly in the case of the “absolute” molecular rotations that asteady increment independent of the individual dispersive powerof the substance or of the series can be looked for. The valueof this steady increment in the (‘ absolute molecular rotation ” ofhomologous series may be deduced by combining Perkin’s meanincrement, 1.023, for sodium light, with the mean value, 1.635, forthe dispersion-ratio of these compounds ; the reduction to“absolute” wave-length then results in a small increase of theincrement from 1.023 to 1,031.It is a matter of interest to see what follows from the assump88 LOWRY: THE ROTATORY DISPERSIVE POWER OFtion of a constant increment, 1.031, in the " absolute " molecularrotations of homologous series of compounds instead of a constantincrement, 1.023, in the values for sodium light.I n the case ofsubstances having the same dispersion-ratio as water, the incrementwould have the same value, 1.031, a t all wave-lengths. Water,with a dispersion-ratio 1.645, is, however, slightly more dispersivethan the simpler series of fatty compounds, which give dispersion-ratios ranging from 1.631 t o 1.639.A series liaving the averagedispersion-ratio 1.635 would give with sodium light the normal-increment 1.023 observed by Perkin; the others would giveincrements ranging only from i.020 to 1.026, a range so narrowthat it could scarcely be detect,ed even in Perkin's most accurateobservations. The relation between the dispersion-ratio and theincrement is shown in the following table :Disperbion ratio ........... 1'645 I *639 1 635 1 *G31Increment forAlwlute wave-lerrgth .. 1'031 1.032 1 *031 1 *031Sodium light .............. 1.031 1.026 1.023 1.020Moicury light ........... 1-031 1.025 1.021 1.017It has already been shown that an abnormally high dispersionis often accompanied by an abnormally high rotation, and con-versely. I n such cases the abnormality is reduced in magnitudewhen the molecular rotation is reduced to '' absolute " wave-length ;but i t would be a great mistake t o assume that all abnormalitiesmust disappear as a result of this reduction.I n the series ofprimary alcohols, for instance, water and methyl alcohol show thesame anomalies of absolute magnetic rotation as were observed byPerkin with sodium light. In other cases, however, the irregulari-ties are reduced in a much more striking way; thus, in the caseof the four aromatic secondary alcohols which have been examined,the series increment for mercury light is about 1.150; but theincrement of the " absolute molecular rotations '' is reduced to1,060, a value that does not greatly exceed the normal increment,1-031, of the €atty compounds.It is therefore probable thatmany o i the irregularities which Perkin observed when he passedfrom the fatty to the aromatic series may be attributed to irregu-larities of dispersive power, and would be reduced or disappear ifthe observations could be reduced to absolute molecular rotations.A bsolute Molecular Rotation in Secondary Alcohols.The large number of pure optically active secondary alcoholsexamined in the course of these experiments renders it possible todraw certain conclusions which could not have been put forwardon the strength of a few Observations of typical compounds. ThORGANIC COMPOUNDS. PART IV. 89absolute molecular rotations of these alcohols were found to be asfollows :c,. 0,. c,. c,.C p c,. 0,. cl,. Cl1. G,?.1\IIethylalkylcarbinols ...... 3.89 4.95 5.98 6‘93 7‘98 9.06 10’09 11’09 12.11 13.30isoPropylalkylcHrbinols . - - 5.94 6-96 7.94 9 06 10.16 11.10 - 13.23._ __. - - __-___Mean ............. 3.89 4’95 5.96 6-95 7-96 9.06 10-12 11.10 12-11 1 3 2 6Calc.. ................. 3-90 4‘93 5-96 6.99 8-09 9 05 10.08 11-11 12’14 13‘18Ethylalkylcarbiiiols ..... 3.89 - .- 6’91 7-98 8-97 9.96 - 12.0T -Calc. ............... C3.841 - - 6’92 7-95 8.98 10.01 - 12.07 -By subtracting n x 1.031 from each of these data, twenty-twovalues were obtained for the “series-constant ” of the alcohols. Itwas found that the “series-constants” for the methyl andisopropyl compounds were 0.805 and 0.803 respectively. This closeagreement (which must be attributed to the large number ofsubstances, seventeen in all, for which data were obtained) provesconclusively that there is no perceptible difference between theabsolute molecular rotations of the methyl and of the isopropylcompounds,* both of which may be expressed by the formula :Abs.mol. rotn. =0*804 + 1’031n.The concordance between the two series is not affected by the omis-sion or inclusion of one or two figures which appear to show largererrors than the others, but which could not be checked becausethe material which had been used for the measurements was nolonger available, There is, however, a steady difference, which istoo large to be attributed to experimental error, between the valuesfor these two series of carbinols and for the isomeric ethylcompounds.These gave a lower series number, namely, 0.735, forthe six carbinols, or 0-724 if the methylethylcarbinol is omitted asbeloiiging properly to the methyl series. The calculated valuesgiven above are derived from the formula:Abs. mol. rotn.=0*730 +1*031n.The number of secondary dCOh016 examined by Perkin was verysmall, but he classified them with the iso-alcohols of the primaryseries, thus :(‘ Alcohols, is0 and sec., 0.844 + 1’023rr.”The present observations show that the branching of the chain ofcarbon atoms does not necessarily increase the molecular rotationof an alcohol which already contains the branched group *CH(OH)*.On the other hand, there appears to be a definite difference, whichPerkin had no opportunity of observing, between the methyl andethyl seria of carbinols.* Attention niay be directed to the auaIogous fact that methyl formate and ho-propyl formatc agree with one another in giving a dispersion ratio, 1‘637 or 1.658,which is higher than the ratio, 1.632, for ethyl and propyl formates (see table I)90 LOWRY : THE AO‘I’ATORY DISPERSIVE POWER OFAbsolute Molecular Rotation in the Ketonee.The ketones, like the secondary alcohols, were studied but littleby Perkin, who classifies them with the iso-aldehydes thus :‘‘ Aldehydes i s 0 and ketones, 0.375 + 1 .0 2 3 ~ ~ ”Here, again, the observations which are now described show thatthe branching of the chain has but little influence on the absolutemolecular rotation, since dipropyl ketone and diisopropyl ketonegive substantially the same value.Moreover, the value 11.55 fordi-n-amyl ketone agrees exactly with the average of the values10.50 and 12.61 for the absolute molecular rotation of the isopropylhexyl and isopropyl octyl ketones. The values for the ketones,omitting acetone, are 0.59 below the values calculated for themethyl and isopropyl carbinols, as set out on p. 89; the actualdifferences are :Normal ketones .... . . ... 0.52 0.67 0.58 0.59 Mean 0 59isol’ropyl ), ......... 0.60 0.57 0’61 0.57 ) ) 0.59The series-number for these ketones is 0-214, and the absolutemolecular rotatlions are given by the formula:Abs. mol. rotn. =0*214 + 1.031~.This figure is considerably below Perkin’s, which would only beincreased from 0.375 to 0.378 by reducing to (( absolute” wave-length.The discrepancy is large, amounting to not less than0.164. A similar but smaller discrepancy exists in the cam of thesecondary alcohols, Perkin’s figure for which would be increasedfrom 0.844 t o 0-851 by reducing t:, (( absolute ” wave-length; thevalue 0.804 given above is 0.047 lower. I n these two special casesi t is believed that the figures now given are more correct thanPerkin’s, since his series-numbers were based upon the valuesobtained for one secondary alcohol (sec.-octyl) and one ketone(methyl propyl ketone) only, whilst the new values are derived fromdata for twenty-two secondary alcohols and nine ketones.Tabulated Meaa.twements.The substances for which data are given in table I were obtainedfrom a number of different sources, and the author wishea t oexpress his indebtedness to several of his colleagues who haveprovided him with valuable materials for the present investigation.In particular he is indebted to Prof.Sydney Young (P) for twopure paraffins and a series of pure esters, t o Dr. F. B. Power (Pr)for a specimen of active isovaleric acid, and t o Dr. R. H. Pickard(P) and Mr. J. Kenyon for a remarkable series of ketones andsecondary alcohols. The other specimens were commercial sampleOSGANIC COMPOUNDS. PART IV. 91from Kahlbaum (K) and Schuchardt (S), purified by fractionaldistillation; in most caseg this was done on a small scale only, asi t was recognised that impurities would be less likely to affect thedispersions than the rotations, and that it was not necessary toattempt t o rival the elaborate work undertaken in this directionby Perkin.The acetic acid, purified as described by Lowry andBousfield (T., 1911, 99, 1432), was, however, undoubtedly purerthan that used by Perkin. The formic acid, like the acetic acid,was purified by freezing. The carbon disulphide had been keptover sulphuric acid during ten years, and was then fractionatedwith a Young "evaporator" still-head. The acetone, from thebisulphite compound, was purified by a similar careful fractiona-tion. The alcohol was dried by quick-lime, as recommended byDr. Nerriman (M) (T., 1913, 103, 629), and had the correctdensity; the methyl alcohol was also supplied by Dr. Merriman.TABLE I.Absolute Magnetic Rotation and Rotatory Dispersion in a Seriesof Simple Aliphatic Compounds aiid ~ T L tour AromaticSecondary Alcohols.Dis-persion- Dis-ratio, persive Abs.mag. rotn.Denhity, Water- a4R59 poHer, +-20"/4". ratio. G1' 1OOA,2. Lowry. Peikin(or calc.),(a) Paraffins.Hexane ... C,H,, .............. Y 0'6595 0.915 1'635 1'96 6.68 6.722Octane ... C8H,, ............... Y 0.7022 0.962 1.634 1'93 8.75 [8-7701Substance.( b ) Primary Alcohots.Water ...... H'OH ................. 0'9986 1.000 1-645hiethyl alcohol, CH,*OH ......... 191 0.7915 0.714 1'629Ethyl ,, C,H5'OH ........... .M 0'7894 0.854 1'634Propyl ,, C,H,'O H ............ K 0'8035 0 -901 1 -635Butyl C,H,*OH .......... 8 0-8042 0 931 1 *636Heptyl ,, C7Hi5'0H ............K 0.8237 0-994 1'685Glycol C,H,(OH), ......... K 1'1088 0.944 1'635Glycerol C,H,(OH)3 ......... K 1.2562 1.006 1'631Octyl ,, CJ317'OH ............ S 0'8270 1-01 5 1 *636Ally1 C,H5*0H .......... K 0'8549 1.239 I.fi722-22 1.001.79 1-631.93 2-791.95 3'761.98 4 611-95 7.841-98 8.923 89 4.551-95 2.951-84 4-111 '0001 *6692.8053-819[4 -82617.9088.9434'5752.9674'172(c) Ether.Ether ...... (C2H5)20 ............ K 0'7135 0.833 1'639 2.05 4'84 4.802(d) Acids.Formic acid H'C0,H . . . . . . . . . . L 1'2196 0.798 1.635 1-95 1 68 1.687Acetic ,, CH;C02H ......... L 1.0491 0.786 1'634 1-93 2.53 2547Propionic ,, C2H5*C02H ......... K 0-9916 0.834 1.635 1-95 3.48 3'494Botyiic ,, C,H7*C02H .........K 0.9640 0.877 1.634 1.93 4.49 4514isoButyric,, CHMe,'CO,H ..... K 0'9504 0.864 1.633 1-90 4-49 4 521iSOVaZeric,, CHMeEt'C0,H ... Pr 0'9419 0.927 1'636 1.98 5.59 5.6792 T,OWRP : THE ROTATORY DISPERSIVE POWER OFTABLE I (continued).Dis-persion- Dis-ratio, persive Abs. mag. rotn.Density, Water- a4.15q p w e r , +-ratio. Til. 100~2. Lowry. Perkin(or calc.).Substance.20"/4".( e ) Esters.Methyl formate, H'C02'CH, ... ...A', , acetate, CH,'CO,*C,H, ... Y, , propionate, C,H,*CO,'CH,. Ybutyrate, C,,H7*C0;CH3 . . YEtcyl formate, H*CO,'C.H, ..... Y,, acetate CH,'CO,'C,H,, ...... YPropyl formate, H*CO,*C,H, ..... Y, . axtnte, CH;CO,'C,H,.. Y ....isoPropyl formate, H'C0,'C,H7.. . S0.97450 93380.91510-8984092260'90050-90580,88840'8i280.7290.7750.8160-8520.7970.8250.8370.5550.846( f ) Ketones.Acetone ...(CH,),CO ............ KMethyl ethyl ketone,C H;CO'C,H, ...... S ,, hexyl ketone,CH,*CO*C6H,, ...... X(C,H,),CO ............ KDiethy1 ketone,Dipropyl ketoiie,Diamvl ketone.(C,K?),CO ............ K(C,H,J2C0.. .......... PDiisopropy 1 k e toil e,isoPropyl wbiit\ 1 k. tonv,isoPropyl n - an I y I kri t on e ,isoPropyl n-hex! 1 ketone,isoPropy1 n-octyl ketone,isoButpl aniyl ketone,Pinacolin.. .(CHMe,),CO ......... PC,H;CO *C,H, ..... .I-'C,H,*CO 'CBH,, ...... PC,H,'CO*C,H,B ...... PC,H,'CO*C,H,, ...... PC,H;CO *C,H,, ...... PCH,'CO 'CMe, ...... iY0.7920 0.8550-8054 0.8840,8202 0977- 0 9200.8217 0 9550.8305 1.0090.5108 0.9430'8176 0.9690.8212 0,9790.8226 0.9910 8264 1.0090.8185 1-0060'8114 0-9231.637 2-01 2.511.629 1.79 3'461.630 1.82 4 421.632 1.87 5.431.632 1.87 3 5 91,630 1'82 4.531-632 1-87 4'541'630 1-82 5.521.638 2.03 4 761.6381 '6381 -6391 *6311.6331'6351.6361,6371 *6371,6371.6331-6401.6402'082 -032 -0.51.841.901'951.982 012.012.011 '902.082-682.5113.402[4'417]5.451 .3.56845144.5375,550[4 '61 413.50 3'5214-41 [4'338]8-38 [8'462]- -7'44 7'54411-55 [11*555]7'42 17'43118.48 C8.46219-47 [9'493]10.50 [10'524]12.61 [12*590]10.69 [10'52;1]6'34 [6-400](9) Secondary AIcohols.Metlzyl tcrt.-bzct?j7carbinol,Pheir y lm dh ?i 7c:n~ b 1 11 o I,PJienyLrthzJ7cctrbinoI,Benxg:mcthyicai t ~ L 7 1 0 7 .8- Phe nylelh ~ i ~ i z r l k ~ ~ l ~ .a ~ b i n o I ,Cf1;CH(OH)*CMe3 ... P 0.8185 1.020 1'643 2.17 7-06CH,,*CH\OH)*C,H, ... P 1.0135 2'074 1'739 4.35 12'77C,T-T;CH(OH)*C,H, ..Y 0'9940 1.963 1,731 4'19 13-81C€I3'CII(OH)'CH,Yh ... P 0'9905 1.957 1'731 4'19 13-83CH;CH(O€I)'C,H,Ph ... P 0 9788 1.881 1'727 4-03 14.90(h) Carbon Disulphide.Carbon disulphide, CS$ ............ L 1.2632 3.250 1'765 4.85 9.80 9.88ORGANIC COMPOUNDS. PART IV. 93The origin of the specimens is indicated by the initid letter onthe right hand side in column 1. The substances of which thenames are printed in italics were optically active; the others wereinactive. The densities shown in column 2 were measured (exceptin the case of Prof.Young's specimens) with a modified form ofPerkin's density-tube. Values for the absolute magnetic rotationcalculated from Perkin's observations are given in the last column :the values for substances which Perkin did not examine werecalculated from his " series-constants," and are given in squarebrackets in €he last column; in the case of the ketones, however,the values given in brackets were calculated from the "series-constant" shown on p. 90 of the present paper.The data for the secondary alcohols are shown in a condensedform in table 11, the denslties having already been tabulated inthe papers of Pickard and Kenyon, whilst the observed and calcu-lated values for the absolute molecular rotations have been set outon p. 89.TABLE 11.Magnetic BotatoTy Dispersion in a Series of Optically ActiveSecondary AIcohols.Methrl-n-alkyl- Ethyl-?r-alkyl- isoPropy1-n-alkgl-cnrbinols. carbinols.cai binols n- ----TZDis- persive Diu- persive Dis- persiveWater- persion- power, Water- persion- power,Water- perhion- puwer,ratio. ratio. 100~,2. ratio. ratio. 100~,2. ratio. ratio. 100~,2.CdHg'OH 0.966 1'636 7.98 - - - - - -C,H,,'OH 0 984 1'636 1 9 8 - - - 0.992 1,641 2-10C,H,,'OH 0~998 1'639 2*U5 0.988 1.632 1 . S i 1'006 1.635 1 95C,H,;OH 1.009 1.639 2.05 1.003 l%30 1-81 1.010 1637 2.01C1otlz,*OH 1.037 1 636 1-98 - - - 1.040 1.633 1 90C,,Hz5'OH 1.066 1'639 2-05 - - - 1-056 1.633 1-90C,H,,'OH 1.022 1.636 1.98 1'014 1'634 1 9 2 1.024 1.636 1-58CgH,g'OH 1'030 1 6 3 5 1.95 1.020 1'634 1'92 1.043 1'636 1'98C,,H;OH 1'043 1'638 2.03 1.123 1.631 1-84 - - -C,AEI,,.OH - - - - - - 1'069 - -Summary and Conclusions.(1) Except in the case of the lowest homologues, the magneticrotatory dispersion in simple organic liquids is remarkably constantin homologous series.(2) I n forty-four fatty compounds the average value of thedispersion - ratio is u4359/u5461 = 1.635, corresponding with anabsorption band at h02=0*0195, ho=0-14 p or 1400 A.U.(3) The values for individual series range from 1-631 for sevenesters to 1.639 for four methyl-ketones.(4) Similar values were observed for the magnetic rotator94 LOWRY, PICKARD, AND KENYON.: THE ROTATORY DISPERSIVEdispersion in glycol, glycerol, ethyl tartrate, and methyl camphor-carboxylate ; water and compounds containing the tert.-butyl groupgive dispersion-ratios a little greater than 1.640; in aromaticcompounds the ratio rises t o about 1.732, and in carbon disulphideto 1.765.(5) The influence of dispersion on magnetic rotatory power maybe eliminated by reducing the observations for every subetance towavelength A = J 1 + h02, where ho2 is the (‘ dispersion constant ” inthe equation a 4 k/h2- b2.As the readings for water are alsoreduced, the ‘‘ absolute molecular rotations ” calculated in this waydo not differ widely from those for green or yellow light, except inthe case of substances the dispersive power of which differs widelyfrom that of water.(6) With the help of the new dispersion-meaeurements, valueshave been calculated for the “ absolute molecular rotations ” ofmany of the substances examined by Sir William Perkin. Valuesare also given for a large number of ketones and secondary alcohols;these have been found to show regular increments in homologousseries, but the ‘‘ series-constants ” differ considerably from thosegiven by Perkin for a few individuals of these series.GUY’S HosrI‘rAx,,LONDOK, S.E

ISSN:0368-1645    

DOI:10.1039/CT9140500081

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

94 LOWRY, PICKARD, AND KENYON.: THE ROTATORY DISPERSIVEXII. - T h e JZotutory Dispersive Power of OrganicConapounds. Payt V. A Comparison o j theOptical and Magnetic Rotatoi-y Dispersions inSome Optically Active Liquids.By THOMAS MARTIN LOWRY, ROBERT HOWSON PICHARD, andJOSEPH KENYON.ONE of the first objects aimed a t in the present experiments on therotatory dispersive power of organic compounds was to compare(1) the natural rotatory disperson and (2) the magnetic rotatorydispersion in a number of optically active liquids. The substanceswhich have been available hitherto for making such a comparisonhave usually been of complicated structure, as in the case of pineneand nicotine; or they have been difficult to prepare in a state ofoptical purity, as in the case of turpentine and optically activeamyl alcohol; they may even have shown anoinalous rotatorydispersion, as in the case of ethyl tartrate. The preparation of alarge number of active alcohols in a state of optical purity (sePOWER OF ONGANIC COMPOUNDS.PART V. 95Pickard and Kenyon, T., 1911, 99, 45; 1912, 101, 620; 1913, 103,1923; and P., 1912, 28, 42) provided a unique supply of materialfor the comparison referred to above, and led directly to theco-operation in experimental work which forms the basis of thepresent paper. The magnetic rotations and dispersions in mostof the compounds used in this investigation have *been given inPart IV of this series of papers; the corresponding optical rotationsand dispersions are set out in the following pages.Wiede.mann’s Law.The comparison of the optical and magnetic rotatory dispersionsin an optically active liquid was first made by G.Wiedemann in1851, five years after the ‘(magnetisation of light” had been ais-covered by Faraday. Wiedernann made a series of comparativemeasurements in the case of turpentine oil with solar light of fivedifferent wave-lengths. After working out the ratio of the tworotations for each wave-length, he concluded that “ These numbersagree so well together that one may assume that the law of pro-portionality of the rotation of the plane of polarisation producedby the current in light of different wave-lengths, with the rotationalready existing in turpentine-oil may be regarded as correct ”(Ann.Phys. Chem., 1851, [ii], 82, 231).After an interval of fifty years Wiedemann’s law was tested byDisch (ktnn. Physik, 1903, [iv], 12, 1153), who discovered markeddeviations, especially in substances showing anomalous rotatorydispersion, but concluded that these were due to lack of homogeneityin the material. Darmois (Ann. Chim. Pltys., 1911, [vii], 22, 247,495), from very similar data, concluded that “the law of pro-portionality was quite inexact, and that Wiedemann’s result was theresult of a pure chance.”A series of experiments on quartz (Lowry, Phil. Tram., 1912, A,212, 295) showed that in this case the proportionality between thenatural and artificial rotatory powers was exact within the limitsof experimental error over a wide range of the visible spectrum.The experiments now described show that this proportionality,which is perhaps a general property of optically active crystals,does not exist in the case of optically active liquids.Occasionally,as in the case of phenylmethylcarbinol, the optical and magneticdispersion-ratios come very close together, but the accidentalcharacter of this agreement is revealed by the wide disagreementin the dispersion-ratios a,35s/a5asl of the next homologue, thus :{ $ 9 (mag.) ... 1.789) { 5 ,, (mag.). 1.731)CtjH,’CH(OH)’CH, (opt.) ...... 1.736 C H *CH(OH)*C,H, (opt.) . 1’6796 LOWRY, PICKARD, AND KENYON: THE ROTATORY DISPERSIVEEqually emphatic evidence that Wiedemann’s law cannot beapplied to organic liquids is afforded by the behaviour of the seriesof fatty alcohols.Thus we find that the characteristic dispersion-ratios for the following series of carbinols are :“ Methyl ” series CH,‘CH(OH)’R (opt.) ..................J “ Ethyl ” series C,H,‘CH(OH)*R (opt.) ..................1 *6511.6391.663{ ’ 9 9’ ,, (mag.) .................. 1.637................ 1 Y 9 8’ 1 9 mag.) 1 633f “hoPropy1” series (CH,),CH*CH(OH)*R (opt.) .......1 $ 9 9 ) 1 ) (mag.) ......... 1 *635The lowest members of the series to show optical activity containa t least four carbon atoms; their optical rotatory dispersions showmarked anomalies (p. 84), but their magnetic dispersions areperfectly normal, thus proving again that Wiedemann’s law cannotbe applied to them.In the case of more complex compounds the discrepancy is stilllarger. Thus, in the case of a complex ester, there is the followingremarkable contrast between ;he two dispersion-ratios :2 -048 Methyl camphorcarboxylate (opt.). ............. { ’9 9 9 (mag ) ............ 1.632Ethyl tartrate, which shows anomalous optical rotatory dispersion,agrees with this substance in giving a magnetic dispersion-ratio1.630, which does not differ from the ratio characteristic of suchsimple esters as ethyl acetate.It is not easy t o explain this inequality in dispersive power.In seeking for an explanation the chief clue is to be found in thefact that the difference between f i e optical and magnetic dispersionsvanishes in the case of quartz, where the optical activity is due t oasymmetry in the crystal structure instead of in the molecule.Inthis case it may be suggested that every part of the moleculecontributes its quota both to the optical and to the magneticrotatory power. In optically active liquids, on the other hand, itis probable that the natural rotatory power is influenced to a muchgreater degree by the atoms or groups of atoms which are nearestto the centres of asymmetry, whilst the magnetic rotatory power isinfluenced to an equal extent by all atoms of a given kind. Theexistence of a rough “additive law” for magnetic rotations andthe highly constitutive character of optical rotatory power may thusperhaps account for the inequality of the two dispersions.The deviations from Wiedemann’s law in the case of opticallyactive liquids suggest a further question, to which a t the presenttime no decisive answer can be given.The inequality in the twodispersions might be attributed : (a) to a change in the value of thPOWER OF ORGANIC COMPOUNDS. PART V. 97dispersion-constant,” ~ ~ 2 , in the equation a= -!k...- (see part 11),A2 - A o ior ( 6 ) to the introduction (as in the case of ethyl tartrate) of asecond term into the dispersion-equation, which then becomes :I n the case of ethyl tartrate, the second term in the equationfor the optical rotation is negative in sign; it is therefore easy t odetect its influence in the anomalous rotatory dispersion of thesubstance (Lowry and Dickson, P., 1913, 29, 185). No anomalyexists, however, in the magnetic rotatory dispersion of this ester,and no deviation from the normal form of the dispersion-curve canbe detected, in spite of the great probability that the liquid containstwo dynamic isomerides with independent dispersion-constants.Itis therefore evidently very difficult to detect the presence of a secondterm in the dispersion-equation unless the two terms differ in signor contain dispersion-constants differing very widely in magnitude.From the theoretical point oi view much might be said in favourof adopting the second of the explanations set out above, but inactual practice no such option exists. There is, in fact, no alterna-tive t o the employment of the simple formula which assumes thatthe deviations in Wiedemann’e law are due to changes in the valueof the dispersion-constant A:.This formula, as has been shownin Part I1 of this series of papers, expresses the form of thedispersion-curves, both for optical and for magnetic rotations, withan accuracy which exceeds that which can be attained in any oneindividual series of observations ; it would therefore be quiteimpossible to determine the magnitude of the four constants in thetwo-term equation, even if it were known that this equation wasthe correct one to apply.Optical Rotatory Dispersion in Rornotogous Series.There is a marked tendency for the optical (like the magnetic)rotatory dispersions in homologous series of compounds 50 settledown t o a steady value after the first members have been passed;but the steady value does not appear until the ccmpound containsfive or six carbon atoms, the abnormalities usually persisting untilthe growing chain has established itself as the largest of the fourgroups attached to the asymmetric carbon atom. Thus we have:VOL.cv. 98 LOWRY, PICKARD, AND KENYON : THE ROTATORY DISPERSIVEMethglcarbinols,CH,'CH(OH)'R. Opt. Mag.R=Ethyl R = Propyl t o decyl ..... i:::;} 1-637 .................Ethylcarbinols, *C,H ,*CH( OH)*R.R = Methyl ............... 1.662R= Rutyl .................. 1 *650R = Amyl, hesyl ......... 1 $391R=isoPropyl ............ 1,6611z'soPropy lcarbi 11 ols,(CH,),CH(OH)*R. Opt. Mag.1'6631 1'635R = Met hy 1 ............... 1 '6 97 1R=Ethyl to octyl ......isoBn t vlcarbinols,R=Methyl ............... 1'631 1'644R=$Ethyl ...............1'633f 1.635R=fPropyl ............... 1.657 1'639(CH,),CH*CH;CH(OH)*R.* The diethylcarbinol is, of coursc, inactive ; the ethylpropylcarbinol has toosmall a rotatory power for an exact measurement of the disllersion ratio.t The agreement with the magnetic dispersion ratio 1'685 is exceptionally close,but does not reappear in the two adjacent homologues and must therefore beregarded as fortuitous.$ These samples were probably not quite pure, but this would not be likely to affectthe dispersion-ratios.The dispersive power of methylisopropylcarbinol is remarkable,especidly in contrast with the steady value 1.663 of the dispersion-ratio in six higher homologues. It ie. however, fully justified by aconsideration of the dispersion-ratios in the series set out below :C H,'CH( OH)*C)H, ........................inactiveCH,'C H (0 H )'C H2 Me ..................... 1 '6621 *697CH,*CH(OH~*CAIC,J ........................ 1'707CH;C H (OH) 'C H Ale, .....................Attention may also be directed to the high dispersive power o f :CHOptically active amyl alcohol, s'CH'CI-I,'OH ........... 1 *700c,H,/CH,Optically active valcric acid, \CH.CO'OH ............... 1 *710C2H5'These two compounds are very similar in structure, and differfrom the active secondary alcohols in that the asymmetric carbonatoms are linked entirely to carbon and hydrogen, instead of t ocarbon, hydrogen, and oxygen. The fact that the oxygen has beenshifted away from the asymmetric atom, instead of diminishing therotatory dispersion, actually itxreases it. It appears, in fact, thatoxygen contributes relatively little to the rotatory dispersion ofthese compounds, which seems to be influenced more by carbon thanit is by oxygen.A bsolufe Molecular Rotation (Optical).In dealing with the magnetic rotatory power of liquids, Perkinselected water as the standard both of specific and of molecularrotation.This choice was justifid by the fact that it is mucheasier t o measure the rotation produced in a deciinetre length oPOWER OF ORGANIC: COMPOUNDS. PART V. 99water than to determine the strength of the magnetic field whichproduces this effect. I n dealing with the natural rotatory powerof optically active liquids, no such standard is needed, as thisproperty can be measured directly in angular degrees per decimetrelength of the liquid; a correction for density or concentration givesthe (‘ specific rotalion,” from which the “ molecular rotation ” mayeasily be calculated without introducing any other substance as abasis for comparison.This fundamental difference in the method of dealing withnatural and magnetic rotations leads to a further contrast when theattempt is made to eliminate the influence of dispersion by workingout the “absolute” rotatory powers of a substance.I n the caseof magnetic rotatory powers the comparative method was extendedt o this final stage in the working out of the experimentalobservations, the magnetic rotation in water being reduced to“ absolute ” wave-length as well as that in the substance.In con-sequence of this extension ot the comparative method the finalreduction produces only slight alterations in the values of themolecular rotatory powers; in the case of substances, such astert.-butyl alcohol, which have the same dispersive-power as water,the “ absolute ” molecular rotation is actually identical with thatfor sodium or for mercury light; 5 table showing the small changesproduced in the case of typical aliphatic compounds is given inPart IV (this vol., p. 88). In dealing with optical rotatorypowers, it is necessary, in order to eliminate the influence ofdispersion, t o reduce the readings f o r the substance to the standardwave-length, a t which h2= 1 + ~ 2 .This produces large alterations,which cannot be diminished o r removed by the use of relative valuesfor two substances. The actual alterations which are produced are$own in the following table fx a series of typical dispersion-ratios :ap5t)/a546, = 1.636 1.644 1’651 1.673 1 735 1.764a,ba,/as6, = 0.2784 0.2763 0.2745 G.2691 0.2555 0.2499a,bs./a5993 = 0.3275 0.3254 0,3237 0.3181 0.3045 0.2989andIn khis table it is seen that the absolute rotations range from28 to 25 per cent. of the rotations for green mercury light, and from33 to 30 per cent. of the rotations f o r sodium light.Tabulated Measureme.rLts.I n table I two series of values are given for the absoluteThe values given in the molecular rotation of each compound.I3100 LOWRY, PICKARD, AND KENYON : THE ROTATORY DISPERSIVEfifth column are calculated from the readings of column 4, whichwere made in London with peen mercury light; the values in thesixth column are calculated from readings which were made inBlackburn with sodium light. I n nearly every case the two valuesagree together closely, but in the few cases in which markeddifferences are observed, the second value is t o be regarded as themore trustworthy.Thus in the case of methylethylcarbinol, thelower value obtained with mercury light is almost certainly duet o the absorption of water, as it was found to diminish steadily insuccessive series of experiments; so also in the case of methyl-IL-butylcarbinol, the sample used for measuring the dispersion wasknown to be of slightly lower rotatory power than the sample usedwhen the sodium readings were taken.The dispersion-ratios and dispersion-constants are set out incolumns 2 and 3.The rotatory dispersion in these compounds isso steady that no new facts are disclosed when the effects of dis-persion are eliminated ; all the essential characteristics of thedrift of rotatory power in honologous series can be seen equallywell in the readings for sodium or for mercury light. Attentionmay, however, be directed to the fact that the small rotations inthe " ethyl "-carbiiiols are associated with exceptionally small dis-persion, whilst the high optical activity of the '' isopropyl "-carbinolsis associated with a high dispersive power ; the '' methyl "-carbinolsoccupy an intermediate position both in rotatory power and indispersive power.This parallelism between rotation and dispersiondoes not apply to the abnormality of the initial members of eachseries, where a low rotatory power may be associated with highdispersive power.Optical Rotatory Dispersion and Absolute Molecular Rotation inSome Optically Active Liquids.ObservedDispersive rotation, ALs. mol. rot.Dispersion- power, a5461 &ratio. 1 0 0 ~ 2 . (100 nim.). L. F'. & I<.( a ) " Methyl 'j Carbinols (normal).Methyl ethyl carbinol .........,, propyl , , .........,, butyl ,, .........,, amyl ,, .......,, hexyl ,, .........,, heptjl ,, .........,. octyl ,, .........,, nonyl ,, .........,, dccyl ,, .......1 '6611-6521-6531.6511'6531.6511 -6491'6511 -6532.622'402 '422.372 '422-372.322.372-4212-57' 1.3.131 3.3013.25 3.95 3-9110.84 [3*72] 3-819.88 3.85 3-889.54 4'14 4'108'68 4.17 4.178'44 4'45 4.437-87 4.50 4-527-52 4'61 4-6POWER OF ORGANIC COMPOUNDS.PART V. 101Optical Rotatory Dispersion and A bsolute Moleculnr Rotation insome Optically Active Liquids (continued).0 bservedDispersive rotation, Abs. mol. rot.Dispersion- power, a5461 &ratio. ~ O O A , ~ . (100 mm.). L.( 6 ) ' I Ethyl " Carbinols.Ethyl prop91 carbinol ......... [1-615~ * [1.39] * 1-60" ,, biityl ,, ......... 1.650 2-34 7.94 .. amyl . . . . . . . . . . 1.639 2.05 8-07 ,, hexyl ), ......... 1.639 2.05 7.80,) octyl ,, ........1.634 1 92 6'1 4(c) " isopropyl " Carbinols.isoPropy1 incthyl carbinol ... 1.697 3-46 4-74"), ethyl . . . . . 1.661 2-62 14-71 ,) propyl ,, ... 1-665 2-74 20'62 ,) butyl ), ... 1.665 2.74 24-97 ), nmyl . . . . . 1.663 2.67 22'46 ,, h x y l ,, ,., 1-661 2.62 51-16,, octyl ,, ... 1.661 2-62 18.38,, decyl . . . . . 1-669 2.86 15'59(d) " Butyl" Carbinols.isoRutyl methyl carbinol.. .... 1 *631 1-92 19'44"tert. -Kntylmethylcarbinol ... I 707 3-68 7-87( e ) Aromatic Secondary Alcohols.Phenylmethylcarbinol ...... 1.736 4 -29 52'49"Phenylethylcarbiiiol ......... 1'674 2 93 32-37Benzylmethylcarbiuol ......... 1.833 6-13 32'47B-Phenylethylmethylcarbinol 1,679 3.03 16 *55d f ) Amy1 alcohol (active) ...... 1.700 3.54 5.40"isoValeric acid .................. 1.710 3-74 20'50f ,, ethjl .. . . . . . . 1.633 1.90 9 *39f ,, propyl ........ 1.651 2-37 4 '990 573-092-543-783-561 *344 -957-8910.6910-6311 *0111.1510.826-852-57--16.1411.9110-576.795.80-1'. & K.0.673'133-503.i83 -561.344.947 8910.6410.5310.8611.0611 -066 -84---15.9311'98 --- -* The rotatory power was too smd1 t o give trustworthy figures for the dispersivet These saniples were of doubtful purity.power of this compound.Summary and Conclusions.1. Optical rotatory dispersion varies more widely than magneticrotatory dispersion, but remains constant in homoIogous series ofsecondary aliphatic alcohols when the " growing chain ') of carbonatoms has established itself as the heaviest radicle in the asym-metric molecule.2. Wiedemann's law, which applies exactly in the ca.se of quartz,does not hold good in the case of optically active liquids. Theoptical is usually greater than the magnetic rotatory dispersion,but the converse is sometimes observed in aromatic compounds102 PERKINS: THE POROSITY OF IRON.3. Remarkable variations of optical rotatory dispersion areobserved in the series:C6H,'CH(OH)'CH, ................ a&a,4G1 = 1.736C,HB'CHiOH~*CII,*CH, ........... ,, = 1'674C, H B*C H,-CH( 0 tI )'C H ............ > IC,Hj.CH2'CH;C1H(O11)'C.H:: ..... > )and in the series:C H ;C H (0 H ) 'CH2 Me ...............CH,'CH(OH)'CHMe, .............. 9 9CH;CH(OH)'CMe, ................. 9 99 ,High dispersion,s are also observed in : '= 1.833= l $ i 9= 1'662= 1.697= 1.707= 1.700= 15'10The expenses incurred in the researches described in this and inthe preceding paper have been defrayed in part by generous grantsfrom the Government Grant Committee of the Royal Society, whichare hereby gratefully acknowledged. Our thanks are also due toMr. W. P. Paddison, t o Mr. H. W. Southgate, and t o Mr. H. R.Courtman for assistance in carrying out the long and tedious seriesof observations recorded in these papers.GUY'S HOSPITAL.LONDON, S.E.MUNICIPAL TECFINICAL SCHOOL.BLACKBURN

ISSN:0368-1645    

DOI:10.1039/CT9140500094

出版商:RSC    

年代:1914

数据来源: RSC

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102 PERKINS: THE POROSITY OF IRON.XII1.-- The Poi-osity of I r o n .By WILLIAM HUGHES PERKINS.IRON which has been immersed for some time in a solution ofalkali hydroxide and then thoroughly washed with water is statedby Dunstan and Hill (T., 1911, 99, 1853) to exhibit a certain‘‘ passivity ” towards nitric acid or copper sulphate and towardsatmospheric corrosion. Friend (T., 1912, 101, 50) believes thisphenomenon to be different from ordinary passivity, and assertsthat it is caused by the retention in the pores of the metal of asmall quantity of alkali, which is sufficient to prevent corrosion.He does not explain why it also renders the iron inactive towardscopper salts and nitric acid. The statement that alkali is absorbedis criticised by H. B. Baker (Annual Reports, 1911, 8, 31), whPERKINS: THE POROSITY OF IRON.103failed to confirm E’riend’s results, using rather more dilute solutionsof the alkali hydroxides. Before Baker’s criticism appeared thepresent author had been led to repeat Friend’s experiments, onaccount of what appeared to him to be a grave defect in the methodused to extract the retained alkali from the metal. After soakingKahlbaum’s iron foil in concentrated (6N) sodium or potassiumhydroxides and then thoroughly washing in a stream of distilledwater, Friend placed his metal in a shallow porcelain dish contain-ing distilled water. It is difficult to see how this procedure couldlead, in the case of sodium a t any rate, to satisfactory blank teste.To obtain distilled water which is free from sodium is no easymatter, and contact with the glaze of a porcelain dish will alwaysproduce a distinct flame reaction in quite a short time.It was feltdesirable, therefore, that the experiments should be repeated inplatinum dishes, and that an attempt should be made to obtainmore conclusive evidence, if possible, of a roughly quantitativenature.The first problem was a careful repetition of Friend’s experimentswith sodium hydroxide. His procedure was followed in every detail,except that platinum dishes were used for the extraction in placeof porcelain. It was possible inmost cases to distinguish between the test and the blank, but thedifference was not a t all striking. A satisfactory blank experimentwas not obtained, even when the distilled water was collecteddirectly from the tin worm of the condenser in the platinum basin.I n the case of potassium the flame test and spectroscopic test aremuch less delicate under ordinary conditions, but it was found that,on carefully concentrating the solution to about 0.1 c.c., there wasa distinct indication of potassium.It might be possible t o arriveat a more definite solution of the problem as far as it concernssodium and potassium hydroxides by the use of more highly refinedmethods and more complicated apparatus, but it appeared moreprofitable at this &age to extend the inquiry to other substances.Baker (Zoc. cit.) mentions the use of barium hydroxide, and thisalkali was chosen for the next experiments. The iron (Kahlbaum’siron foil) was immersed for three months in nearly saturatedbaryta water in an atmosphere free from carbon dioxide.It waethen well washed with distilled water until after soaking for fiveminutes, the solution gave no turbidity with sulphuric acid and noflame coloration. The metal was then immersed in dilute hydrechloric acid for an hour, the liquid being then poured off througha filter and tested for barium with sulphuric acid and by the flamecoloration. A distinct cloudiness and a green flame colorationwere always obtained from the test and none from the blankThe result was very uncertain104 PERKTNR: THE POROSITY OF IRON.solution. It is possible, however, that the barium may have beenretained on the surface of the iron as insoluble carbonate formedfrom the traces of carbon dioxide which could not be asmmed tobe absent from the metal.Further experiments were thereforecarried out xith lithium hydroxide. A saturated solution of thisalkali was mixed with about one-fifth its volume of boiled distilledwater. Pieces of iron 5 x 4 cm. in area were immersed in it forperiods varying from three weeks to six months, the vessel beingkept well stoppered. When the metal was removed it was wellwashed, first under the tap and then in a stream of distilled water,being subjected at the same time to vigorous rubbing either withthe fingers or with cotton-wool. This process occupied from ten totwenty minutes in each case. After a final thorough rinsing it wasplaced in a platinum dish containing about 5 C.C. of distilledwater and left for about twenty-four hours.The water was thenpoured off into a clean platinum crucible, evaporated down to aboutone-fifth of a c.c., and then tested by the flame test on a cleanwire. There was in all caaes a distinct coloration, which was notobtained in any of the blank tests. For the blank tests a pieceof the same iron was treated in exactly the same way, except thatit was not immersed in the lithium hydroxide. It is, of course,possible, on account of the relative insolubility of lithium carbonate,to advance against these results arguments similar to those usedin the case of barium. The solubility of lit’hium carbonate, however,is so distinct (more than 1 per cent. a t 1 5 O ) that i t is not likelyto have been retained as a surface deposit during such thoroughwashing.The substitution of electrolytic iron (Schuchardt) forthe iron foil did not modify the results obtained. A gold cruciblewhich had contained lithium hydroxide for some months, afterwashing well for five or ten minutes with running water, requireda daily change of water for more than four weeks before thespectroscopic test for lithium failed to show its presence in thewater. It is clear, therefore, that traces of alkalis, and presumablytherefore other solutions, are retained by metals in such a way thattheir extraction is a slow process of simple diffusion, and cannot behastened by shaking or even by gentle rubbing. Whether this isdue to actual porosity or to the formation of a surface layer isnot quite clear, but the “ absorption ” is obviously very slight.Toobtain some estimate of the absolute quantity an attempt was madeto obtain approximate figures, using ammonium hydroxide as thealkali and Nessler’s reagent as a quantitative indicator. A largepiece of iron foil about 500 sq. cm. in area (reckoning both sides)was well polished and cleaned, and then immersed for six weeksin concentrated ammonia solution. The washing was carried outfirst with distilled water, and $hen at the end wikh four changes oPERKINS: THE POROSITY OF IRON. 105ammonia-free water (500 C.C. contain less than 0.000002 milligramof ammonia). As a rule, the washing, after three or four prelimin-ary rinsings, required about fifteen minutes and about ten changesof water, the last four each remaining in contact with the metalfor two minutes.The metal was then covered with 500 C.C.ammonia-free water in another vessel and left for three days. Atthe end of this time all the water was distilled through anammonia-free condenser, and the distillate tested. Four experi-ments gave quantities of ammonia varying from 0*00002 t o0*00003 gram for 500 sq. cm. of metal. A quantity of this order ofmagnitude may or may not be sufficient to account for the anoma-lous behaviour of the iron which retains it, but it is doubtfulwhether one is justified in assuming that it is retained by actualcrpores’7 in the metal. I n connexion with ammonia one difficultywas kindly pointed out to the author by Professor Smithells.Itwas a t one time believed that ammonia was formed during therusting of iron, and this view has not, to the knowledge of thewriter, ever been confuted. The German edition of Berzelius’s“ Lehrbuch der Chemie ” (1834) contains the following paragraph(Vol. III., p. 427):“ I n trockner Luft oxydirt sich das Eisen nicht, um so rascheraber in feuchter und besonders bei Gegenwart von vie1 Kohlen-saure. Es entsteht hierdurch der sogenannte Rost, welcher einGemenge von kohlensaurem Eisenoxydul mit Eisenoxydhydrat ist.Das Eisen oxydirt sich dabei nicht bloss auf ICosten der Luft,sondern zugleich wird auch Wasser zersetzt, dessen Wasserstoff sichim Entstehungszustande mit Stickstoff aus der Luft zu Ammoniakverbindet.I n dieser Reaction besteht zwar nicht hauptsachlichdie Oxydations-Erscheinung, sie findet aber doch stets so unverkenn-bar staat, dass ein schwach gerothetes Lackmuspapier, welchm manin eine verkorkte Flasche aufgehangt hat, auf deren Boden sich mitWmser angefeuchtete Eisenfeilspahne befinden, nach wenigenStunden geblaut wird. Ein Theil des sich bildenden Ammoniaksverbindet sich rnit dem Eisenoxyd, und so enthalt auch sonderbarerWeise alles mineralisch vorkommende Eisenoxyd, 60WOhl das ausden Urgebirgen, als das aus jungeren Formationen, Spuren vonAmmoniak, welches in Destillations-gefiissen ausgetrieben werdenkann.* Diese Verhaltnisse sind zuerst von Chevallier beobachtetworden.”It appears, therefore, if this view is correct, that a quantity ofammonia may be produced in the period during which the ironis immersed in the distilled water when it undergoes a, gooddeal of corrosion. Carefully conducted experiments have shownThis statemeut is repeated by MeiidelBev (Principles, 1891, Vol. II., 318)106 SEGALLER THE RELATIVE ACTIVITIES OFthat the ammonia produced during the rusting of large pieces ofiron foil, which lost from 0.4 to 0.6 gram in weight in the process,was less than 0-000002 gra.m, as determined by Nessler’s reaction.The experiment with litmus paper as indicator could not berepeated, whilst the geological evidence, bearing in mind the natureof iron oxide, is not very surprising.It may be remarked, in conclusion, that in all the author’s experi-ments the iron which had been soaked in alkali and then wellwashed, rusted much more irregularly, and was more liable topitting than iron which had not been so treated.THE UNIVERSITY, LISEDS

ISSN:0368-1645    

DOI:10.1039/CT9140500102

出版商:RSC    

年代:1914

数据来源: RSC

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106 SEGALLER THE RELATIVE ACTIVITIES OFX1V.- The Relative Activities of Certuin Organiclodo- compounds with Sodima Phenoxide inAlcoholic Solustion. P a ~ t 111. The Temperature-coe$icients.By DAVID SEGALLER.THE influence of temperature on the rate of reaction betweenaliphatic alkyl iodides and sodium phenoside in alcoholic solutionhas been studied, particularly with the object of determining therelative activities of these compounds when the effect of tempera-ture can be excluded.The following substances were dealt with : methyl, ethyl, propyl,isopropyl, butyl, isobutyl, sec.-butyl, tert.-butyl, amyl, isoamyl,sec.-amyl, hexyl, sec.-hexyl, heptyl, sec.-heptyl, octyl, sec.-octyl, andhexadecyl iodides, and their velocity-coefficients were measured atfour different temperatures (with two exceptions, which were onlymeasured a t three temperatures) over a range of approximately 50°.The temperature-coefficients are very large, most of the iodidesmentioned above being more than twenty times as reactive at 58Oas they are a t 3 1 O .Ths value K(,+,o, / Kt is practically constant throughout the series,and lies between 3-01 and 3.09.I n his principle of mobile equilibrium (,i!?t.rrdes, p.222), van'tHoff deduces the equation :* (1)9 dlogK - - - QdT 2Tz * ' a ' * CERTAIN ORGANIC IODO-COMPOUNDS, ETC. 10'7where q is the heat evolved in the formation of the system.on integration, leads tot the approximation :This,( a 1A9 m I'logK = 2 + c o n s t . = -+h . . . .421where A and b are both constants.It €ollows from equation (2)280 290 300 31 3 32010i x Reciprocal of absolute tcmpwatzwe.A = tert.-Butyl iodide.B = Methyl iodidc.C = Ethyl iodide. E = is0 PropgE iodide.D = Propgl iodida. F = sec. - OctyE iodide.G = Amy1 iodide. H = isoButyl iodide.that if log K is plotted against l / T , the reciprocal of the absolutet'emperature, the graph obtained should be a straight line.The velocity-coefficients obtained were plotted against 1/ T inthe diagram, and it is seen that the graphs are straight linesin all cases. The fourth point connecting the reciprocal of th108 SEGALLER : THE RELATIVE ACTIVITIES OFhighest temperature and the velocity-coefficient obtained lies some-what off the line in every case, the value of R, for each substancebeing lower than that obtained from the curve.This cannot be dueto experimental error, as the only possible variation from themethod adopted in determining the velocity-coefficients a t the otherthree temperatures lies in the fact that the reaction was notstopped as promptly in the case of the sealed tubes as in thosecases where stoppered tubes were employed. The error involvedhere, however, would be that. the time 6 would be somewhat largerthan that given in the tables, and consequently 2K4 would besmaller, instead of greater, than the value found. The only otherpossible source of error, namely, pressure in the tubes, could onlybe minute. It has been shown by a number of observers (Rontgen,A nn. Phys. Chem., 1892, [iii], 45, 98 ; Rothmund, Zeitsch.physikal.Chem., 1896, 20, 168) that the influence of pressure on the velocityof reaction between liquids is very slight. The reason for thelower values of K4 is probably to be found in the fact that themagnitude of p is dependent on the temperature, so that equation(2) holds only over a limited range.Very little work has been done up to the present in connexionwith the relative reactivities of any homologous series a t differenttemperatures. The work that has been published does not tendto show any regular increase or decrease in reactivity with anincreaae of *CH, in the molecule in an homologous series; forexample, Price in his research on ester saponification (Ofvers.E . Vet. Akad. Stockholm, 1899, 56, 932) gives values which showthat there is practically no difference in the magnitude of thevelocity-coefficients of methyl, ethyl, propyl, and isobutyl acetates.Crocker, on the other hand (T., 1907, 91, 611), by comparing thereactivities of the aliphatic amides, shows that there is a gradualtransition in the relative activities of the first eight homolopeswith increasing molecular weight.EXPERIMENTAL.It has been shown by the author (T., 1913, 103, 1162) that, inthe action of alkyl iodides on sodium phenoxide, the initial concen-tration of the reacting substances has a large influence on themagnitude of the velocity-coefficients. It was theref ore necessaryto perform all the reactions at the various temperatures with thesame initial concentration in order that the results should becomparable, and this made the times for half reaction vary fromten minutes t o seven days.The concentrations of both the phen-oxide and iodide used throughout this work was N/10, and themethod adopted for the three lower temperaturcss is the same aCERTAIN ORGANIC IODO-COMPOUNDS, ETC. LO9that already described (T., 1913, 103, 1154, 1422), the additionalprecaution being adopted of blackening the outsides of all vesselsused. I n the case of the highest temperature employed (80*1*) i twas necessary to work in sealed tubes. These tubes were made tohold just over 20 c.c., and were drawn out to a narrow end justwide enough to admit a special pipette with a very narrow stem.The reaction mixtures were transferred to the tubes by means of apipette, the narrow ends drawa out to a point and sealed off.Duringthe sealiug, the tubes rested in an asbestos cloth bag. As each tubewas removed from the thermostat i t was rapidly cooled by immer-sion in a large volume of mercury on which ice was floating. Thistreatment cooled the reaction mixture to the room temperature ina very short time. The capillary was then broken off, the contentsof the tube were thoroughly washed out into a beaker containingthe N/20-acid, and the titration was completed as described.The method of calculating the velocity-coefficients was the sameas before, and the following table gives the results of the measure-ments, showing the mean values of K at the four temperatures:30.1°, 42'5O, 58'5O, and 80'1O.Substance.Methyl iodide ............n-Butyl , , ............n-Amy1 ,, ............n-Heptyl ,, ............12-Octyl , , ..........w-Hexadecyl iodide ...isoButyl ,, ...isoAmyl ,, ...isoPropyl ,, ...sec.-Rutyl ,, ...~ e c .- A l ~ y l ,, ...sec.-Hexyl ,, ...sac.-Heptyl ,, ...sec.-Octyl ,, ...tert.-Butyl ,, ...Ethyl ,, ............R - Prop yl , , ...........n-Hiexyl , , ............4. K2. K3. KPTemperature, Temperature, Temperature, Temperature,30.1". 42.5". 58.5". 80'1".0.01550-003420-091280*001270.0005450 -001210'001160*001090-OOlOf0*0005120.0007270 001230.001320'001 200*001130 -00 1100.001070.0295OaO6070.01350 005200.004h50 *002100 *OO 4 ti 40*004 5 10-004340.004290 -00 1930 002850'004650,005130'004700.004330 004200 004110.1210.3260.07 100.02830 02670.01170.02550.0'2480-02410.02310.01030.01560.02590.02770.02600.02400.02300'0226Temperature 0"-0.5100 2090.1 970.0850.1920.1900.1870.1840'07000.07600 '1 930-2050.1970.1780.1700.1680.000381The relationship between the velocity-coefficients and the tem-perature is expressed much more accurately by an equation thanby a graph.The data obtained above are well represented by theequation K/K,= (Z'/To)B, proposed by Harcourt and Esson (Phil.Trans., 1867, 157, 117; 1913, A , 212, 187), but are betterexpressed by Arrhenius' equation (Zeitsch. physikal. Chem., 1887,4, 226):.. . . . p,where A is a constant110 SEGALLER : THE RELS'I'IVE ACTIVITIES OFIn the following table the values of K , are compared with thosllecalculated by means of equation (3) :K2 K2Snbstance. Kl4 A:. A. calculated. found.Methyl iodide ......... 0.0155 0.326 4850 0.0591 0.0607Ethyl ,, ......... 0.00342 0.0710 4825 0.0130 0.0135Propyl ,, ........ . 0.00128 0.0283 4922 0*00500 0*00519isoPropyl iodide ... ... 0*00123 0'0259 43-16 0'00465 0'00466But-yl ,, ... ... O*OOl2T 0.0267 484% 0'00494 0,00485isoButyl ,, ...... 0*000512 0'0103 4778 0*00192 0*00190sec.-Butyl ,, ...... 0'00132 O.OU277 4844 0'01,1502 0,00513tert.-Butyl ,, ...... 1~00~000381 .K10*121 5100 K20'0301 0,0295Amy1 ,) ... ... 0-000545 0.0117 4887 0.00210 0.002102isoAniyl ,, ......0*000727 0 0156 4880 0.00279 0 00285Hexyl ,, ... ... 0'00181 0'0255 4852 0.00461 0'004641Heptgl ,, ...... 0.00116 0.0218 4 8 i 4 0'00445 0 00451sec.-Heptyl ,, ...... 0'00110 0 0230 4845 0.00318 0.00420JOctyl ,, ...... 0.00109 0.0232 4933 0.00435 0.00434-jHexadecyl ,, ...... 0 0010i 0-0236 4918 0 00417 0'60429J .The "constant " A varies very little throughout the series, andif the interpretation of Arrhenius is adopted, then A representsapproximately half the heat required to convert the inactive forminto the active. It follows also that the heat of transformationfrom the inactive to the active form is independent of the tempera-ture. This is apparently the case for the range of temperatureconsidered in this investigation (excluding the highest tempera-ture).Comparing the series separately, for example, normal primary,iso-primary, secondary, and tertiary, it will be wen that the velocity-coefficients become gradually less with increasing molecular weights,and in no case was there any inversion of the order of reactivitiesfrom one temperature to another.If the velocity-coefficients ar0 examined in relation to one anothera t the various temperatures, some remarkable points are noticed.I n the following table the velocity-coefficients are given relativelyto methyl iodide, the velocity-coefficient of which is taken equal to1000.Kl, E2, li, are the "relative" velocity-coefficients a t the tem-peratures 31'0°, 42'5O, and 68'5O.s~c.-A111yl ), ......0*00120 0'0260 4893 0.00463 0'00470JSCC.-HCXYI ,, ..... 0.00113 0'0240 4SGti 0 00433 O 00433 :sec.-Octyl ,, ...... 0'00107 0 0226 4848 0'00409 0'00411Subst awe.Methyl iodidc ...... ... ... ...Et liyl . . . . . . . . . . . . . .Propyl ), ... ,...........Butyl , , . . . . . . . . . . . . . .see.-Butyl iodide .. , . . . .. . . . .tert. - I5ntyl , , . . .... . , , . ..Amj1 ,, ... . . . , . . .. .,,7koPropyl , ,is0 t< uty 1. . . . . . . . . . . . . . ., , . . . . . . . . . , . . . .Kl*1000 -0221 -182-7579.6982-2233-0785.1335-211904 0K2.1000~0222'185-6376 5681-3731 3 084-4834-671987'0K3.1000*0217.686.5859.418 I .9631-5184.8236.00CERTAIN ORGANIC IODO-COMPOUNDS, ETC.Substance.isoArnyl iodidesec. -Aniyl ,,Hex$ 2 ,Heptyl 9 2OCtYl > 7 sec.-Octyl ,)SCC.- Hexyl , ,set.-Heptyl ,)Hexadecyl ),............ .......... ...................................................................... ............Kl*46.9577-5277.5072.8874.8070.7471'4769'2669-33K!P46.967 7 -457 6 4 97 1.4274.3069-1670-4269.0070 76111K3*47'9779.5478.0173.6076.0170.4774.3269'1172.38The numbers in the above table show that approximately therelative velocity-coefficients of the alkyl iodides are independent ofthe temperature. I f a mean is taken of the velocity-coefficientsrelatively to methyl iodide a t t.he temperatures considered, wetherefore obtain a series of numbers which express the relativereacOivities of the alkyl iodides independent of the temperature.The following table gives the order of the reactivities so obtained :tert.-Butyl iodide ......1945'0Methyl , , ...... 1000 '0Propyl ,, ...... 84.95), 81.85 ButylisoPropyl , , 78 *53sec.-Amy1 ) ) ...... 78-17Ethyl ) ) ...... 2 2 0 2 .~ c . - B ~ t y l ,, ...... 84.81 ' ...... i ......Hexyl ,, ...... 77 3 3Heptyl iodide .........sec. - Hexyl , , .........Octyl ,, .........Hexadecyl , , .......sec. -Heptyl ), .........see. -0rtyl , , ........isoAniyl ), .........isoButyl , , ......... Amy1 ,) .........74-7072-6372.0770.8270.1269.1242 2935'2931.96Gepneral Conclusions.(1) The temperature-coefficients of the alkyl iodides with sodiumphenoxide in alcoholic solution are large, the ratios of the velocity-coefficients for two temperatures differing by 10 degrees are fairlyconstant for the series, and lie between 3-01 and 3.09.(2) The coefficients found for the three lower temperatures arein good agreement with those found by means of the equation ofArrhenius. Jn the case of the highest temperature the valuesfound are in all cases somewhat lower than those required by theformula, since the equation holds only for a limited range.(3) The results show that the relative activities of the alkyliodides towards sodium phenoxide are almost independent of thetemperature.( 4 ) The relative activities of the alkyl iodides may therefore beexpessed by the relative numbers representing their velocity-coefficients, ,(5) The reactivities so obtained are in the following descendingorder of magnitude : tcrt.-butyl, methyl, ethyl, propyl, sec.-butyl,butyl,'isopropyl, sec.-amyl, hexyl, heptyl, sec.-hexyl, octyl, hexadecyl,sec.-heptyl, set.-octyl, ieoamyl, amyl, isobutyl112 SEGBLLER : THE RELATIVE ACTIVITIES OFThe author wishes to express his thanks to the Research FundCommittee of the Cheniicnl Society for a grant which has helped todefray the expenses of this investigation, and to Dr.J. C . Crockerfor his kindness in supervising this work.CH EM ICA L DEP A It TM E K T,8. If’. POLYTIICHNIC,CHELSEA, S. W.THE RUTLISH SCIIOOL,MERTOK, S. W

ISSN:0368-1645    

DOI:10.1039/CT9140500106

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

112 SEGBLLER : THE RELATIVE ACTIVITIES OFSV.--The Relative Activities of Certain O r p n i c todo-comp~urtds with Sodium Plzenoxide. P a ~ t I V.Y’he Injuence of the Solvent.By DAVID SEGALLER.IT is well known that the solvent has an enormous influence onchemical reactions generally, but up to the present comparativelyfew workers have made measurements of the velocity-coefficientsof reactions with a view t o study the effect of the medium. Prac-tically nothing is known of the mechanism of reactions in whichthe solvent plays an important part, and although there are oneor two theories which attempt to account for this influence of thesolvent, there is as yet very little experimental evidence with whichto test these theories. We owe our most complete data probablyto Menschutkin, who studied the rate of formation of tetraethyl:ammonium iodide in about twenty solvents at looo (Zeitsch..physiknl.Chem., 1890, 6, 41). Menschutkin also investigated theinfluence of the solvent on some other reactions, for example, theaction of acetic anhydride on isopropyl and on isobutyl alcohol(ibid., 1887, 1, 611). Walden (ibid., 1908, 61, 633) measured thereaction-velocities between triethylamine and ethyl iodide invarious solvents a t 50°.It has been sought a t various times to connect the change of thevelocity-coefficients with change of the solvent in various reactionswith some physical properties of the solvent, such as viscosity anddielectric constant.Very little evidence has been produced to enable us to connectthe viscosities of the solvents with their influence on the rate ofreaction.On the other hand, i t is probable, as suggested byThomson and Nernst, that substances with the higher dielectricconstant would have a higher ionising power, so that if a givenreaction takes place between ions (and this is by no,means provedfor all organic reactions) the velocity of such a reaction would begreater in the solvent which has the greater dielectric constantCERTAIN ORGANIC IODO-COMPOUNDS, ETC. 113A comparison of the velocity-coefficient obtained by Menschutkinwith the dielectric constants shows that there is a certain q u a l i htive connexion. As shown below, the results of the measurementsdealt with in the present paper do not support the view thatthere is any direct connexion between the influence of the solventand its dielectric constant.Van’t Hoff (Vorlesimgen, 1901, 1, 219) has put forward animportant theory t o account for the influence of the solvent.He supposes that the effect of the solvent is due to two factors:(a) a catalytic action, and ( b ) an action depending on the solu-bility relations between the reacting substances and the solvent.For the latter effect he deduces the equation K’=K*S, so thatK’ is the product of the velocity-coefficients found and the solu-bility- or partition-coefficient of the reacting substances.A number of investigators conclude that the theory of van’tHoff actually does account for the facts observed by them; thusDimroth (Anrulen, 1910, 377, 127) has measured the velocityof transformation of methyl 5-hydroxy-l-phenyl-l : 2 : 3-triazole-4-carboxylate into its neutral isomeride in a number of solvents atloo.He shows that there is no relationship between the influ-ence of the solvent and the dielectric constant, but that there isa direct connexion between the velocity of transformation of oneisomeride into the other and their solubilities. The catalytic effectof the solvent is only minute.Von Halban (Zcitsch. physikal. Chem., 1909, 67, 129) in aninvestigation on the decomposition of triethylsulphonium bromide,and Bugarsky (ibid., 1910, 71, 705) from experiments on thereaction between bromine and ethyl alcohol, both support theconclusions of Dimroth.On the other hand, Freundlich and Richards (ibid., 1912, 79,681) in a recent paper find no connexion between the rate oftransformation and the solubility of chloroamylamine in piperidinehydrochloride.The present communication deals with the change of thereaction velocities between ethyl and propyl iodides with sodiumphenoxide in the following solvents : methyl alcohol, ethyl alcohol,propyl alcohol, isobutyl alcohol, isoamyl alcohol, and acetone.An,experiment was also made in ethyl alcohol, some sodium iodidebeing added to the solution.EXPERIMENTAL.The measurements of the velocity-coefficients were carried outWith exception of the reaction in acetone, all solutions were N / 5 ,VOL. cv. 1as described by the author (T., 1913, 103, 1154, 1421)114 SEGALLER : THE RELATIVE ACTIVITIES OFand the velocity-coefficients were calculated as before.I n the caseof acetone the procedure was somewhat different. Sodium phen-oxide dissolves very readily in boiling anhydrous acetone, and oncooling long, colourless needles crystallise out, coiitaining onemolecule of acetone of crystallisation. The needles gave onanalysis Na = 13.18. C,H,*ONa,(CH,),CO require Na = 13-22 percent.A t the temperature of the atmosphere a N/5-solution of sodiumpheno-xide is almost solid. For this reason and also on account ofthe very great rapidity of the reaction in acetone solution N/10-solutions were employed.The reaction mixture was in this case prepared a t the tempera-ture of the thermostat in a stoppered Jena-glass bottle, and atvarious intervals of time 20 C.C.were withdrawn by means of apipette also warmed to the temperature of the bath. The measurement was then completed as before. The temperature of thethermostat WM 58'6O.(4.t.356992112160(4 *t.506090130147t.6090120Solvent : Methyl Alcohol(Zero = 19 '40 C.C. ).a - x. K.16-27 0'028314.32 0'026513.10 0.026912.02 0 028210.35 0.0281Rmean = 0*0276.Solvent : Propyl Alcohol(Zero=18*15 c.c.).G - x. K.13-39 0.939112-75 0.038911.30 0.03719'65 0-03749.00 0'0361K mean = 0.0381.(6). Solvent : Ethyl Alcohol(Zero= 18.95 c.c.).t. a - x. K.14 16 -21 0-063622 15.03 0.062838 13 12 0.061860 11.19 0.061090 9.22 0'0618K mean = 0.0622.( d ) .Solvent : isol3utyl Alcohol(Zero = 18.25 c. c. ).t. ( I - x. K.30 16.72 0-016770 14.70 0'0189100 13'15 0.0212130 12.92 0.0175146 11.75 0.0191Kmean = 0.0187.(e). Solvent : GoAmy1 Alcohol (Zero= 19-50 c.c.).a - x. 1% t.' a - x. K.13.00 0'012312.32 0.0121l i . 0 0 0'012515.95 0.012615.01 0.0128 Kmean = 0'0124CERTAIN ORGANIC IODO-COMPOUNDS, ETC.Propyl Zodide.115(a). Solvent : Methyl Alcohol(Zero=l9*10 c.c.).t. a - z. K.30 10*00 0'010660 16.85 0-0116100 15.35 0.0126130 14-95 0'0110140 14.56 0.0116Kmean = 0.0115,(c). Solvent : Ethyl Alcoliol(Zero= 18'60 c.c.). N/lO-Sodium Iodide.t. a - x. K.50 15'50 0'021570 14'53 0'021591 13 '59 0.0223115 12'40 0'0242130 12.00 0'0227K mean = 0.0224.(e). Solvent : isoButyl Alcohol(Zero = 19'20 c.c. ).t. n - 2 . . K.70 17-30 0'00818120 16'28 0'00776150 15.80 0.00775247 14'92 0 *O 0 829350 12-52 0.00792Kmean = 0'00798.(6).t.507090102117(d 1.t.4061100120140(f 1.t.116158230366453Solvent : Ethyl Alcohol(Zero=18'30 c.c.).I t - x. K.14.90 0'094913.92 0.02451'2 -82. 0'065912-60 0 024311 *95 0.0248K mean = 0 0249.Solvent : l'ropyl Alcohol(Zero = 18.85 c.c.).a - z. K.16-78 0*016415.80 0'016714.62 0.015313 90 0.016113'35 0'0158Kmean = 0.0161.Solvent : isoAmyl Alcohol(Zero=19.96 c.c.).a - x. hi.17 *52 0'0060116.96 0-0056116 '30 0,0048914'70 0'0039113'25 0.00560K mean = 0.00540.(9). Solvent : Acetone (Zero=10'50 c.c.),t.a - x. K.7 8-40 0.67012 7 -50 0-63417 6.60 0.727t. a - x. K.23 5.80 0.65741 4-70 0.599K mean = 0.657.The results obtained are summarised in the following table,which contains the mean valuea of the velocity-coefficients for ethyland propyl iodides. The third column gives the dielectricconstants of the solvents at 20°:Ethyl .Propyl hielectricSolvent. iodide. iodide. constant.Methyl alcohol ........................... 0.0976 0-0115 31'2Ethyl ,, ........................... 0'0622 0.0249 25.8(Mixture containing N/lO-NaI) 0 '0224 -Propyl alcohol ........................... 0-0381 0.0161 22 2isoButyl ,, ........................... 0 '01 87 0 *OO 7 98 20 0isoAmyl ,, .......................... 0.01245 0'00540 16'0 ........................... 0-657 21 *5 Acetone -The results show that there is no obvious connexion betweenthe influence of the solvent and its dielectric constant. It wasI 116 SEGALLER : THE RELAllVE ACTIVITIES, ETC.to be expected that the reaction in methyl alcohol would be thefastest of those in the alcohols, and Menschutkin finds the reactionhe investigated t o be faster in methyl alcohol than in ethyl alcohol.The values of K obtained here, however, show that the velocityis less in methyl alcohol than in ethyl alcohol.This fact issupported by Eecht and Conrad (Zeitsch. physikal. Chem., 1889,3, 421, who find that the rate of ether formation is less in methylthan ethyl alcohol.The following table compares the relative reactivities in thevarious solvents found in this investigation with the results ofMenschutkin for tetraethylammonium iodide and of Hecht andConrad.The value of K in methyl alcohol is taken as unity ineach case:Sodium phenoxide Hechtand propyl iodide. and Conrad. Menschutkin.Methyl alcohol .................. 1 '00 1 -00 1'00Ethyl !, .................. 2-17 1 *95 0 *71Propyl ,, .................. 1 -40 - -isoButy 1 . , ................. 0.69 - 0 '50isoAniyl , 0 '47Ace tone .................. 57'13 - 1-18. .................. - -The velocity in acetone solution is remarkably high. This highvalue, taken in conjunction with the small velocity in methylalcohol, leads to the conclusion that the reaction considered isprobably not one between ions.This conclusion is, however, difficult to reconcile with the resultobtained when sodium iodide was added to the reaction mixture,the velocity-constant being thus somewhat lowered.An attempt to appIy van% Hoff's equation t o the resultsobtained does not give any connexion between the solubility andthe influence of the solvent; the product of the solubilities ofsodium phenoxide and of ethyl iodide in the alcohols varies onlyto a slight extent, and not a t all in consonance with the largevariations in the velocity-coefficients.The r61e of the latter musttherefore be assumed to be catalytic.I n connexion with the above results a slight modification mightbe suggested in the preparation of phenol ethers.The usual laboratory methods for the preparation of anisole,phenetole, etc., require several hours' heating.The very highreaction-velocity in acetone solution suggested the preparation ofthese substances in acetone solution. Sodium phenoxide (1 mol.)was dissolved in boiliiig acetone, and methyl iodide (li mols.)added. The mixture was boiled under reflux for fifteen minutes,and the oil separated in the usual way. A yield correspondingwith 95 per cent. of the theoretical was obtained. The methoCONSTITUTlON OF THE ORTHO-DIAZOIMINES. PART IV. 1 'rwas also tried for the preparation of phenetde and of phenylhexadecyl ether with the same results.General Conclusions.(1) The solvent medium has a considerable influence on thevelocity of reaction between alkyl iodides and sodium phenoxide.(2) There is no relationship between the influence of the solventand its dielectric constant.(3) The connexion between the solubility relations and theinfluence of the solvent suggested by van't Hoff does not hold inthis reaction, and it is to be msumed that the r81e of the solventis that of a catalyst.(4) The results obtained indicate t.hat the reaction is not" ionic."The author desires to express his thanks to the Research FundCommittee of the Chemical Society for a grant which has helpedto defray the expsnsm of this investigation.THE SOUTH WESTERN POLYTECHNIC, THE Ru'rLIsH SCIIOOI,,CHELSEA, S. W. MEKTON, S.W

ISSN:0368-1645    

DOI:10.1039/CT9140500112

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

CONSTITUTlON OF THE ORTHO-DIAZOIMINES. PART IV. 1 I 'rXV 1.- Constitution of the ortho- Dirxoirnincs. Part I V.home p i c Benzenesulp hon y l-3 : 4 - t ol y lenr diazoimid es.By GILBERT T. MORGAN and GODFREY EDWARD SCUFF.IN a recent communication (T., 1913, 103, 1394) it was demon-strated that the isomerism of the two so-called a- and 8-acetyl-3 : 4-tolylenediazoimides is of a structural nature, and due to differencesin the orientation of the double linking and acetyl group in theisotriazole ring. The preparation of a similar pair of isomericbenzoyl-3 : 4-tolylenediazoimides showed, moreover, that the exist+ence of these isomerides is not dependent on the specific characterof the acyl group present. The four acylated ortho-diamines fromwhich these two pairs of isomeric diazoimides were prepared undergocondensation very readily, passing into ethenyl and benzenylanhydro-bases respectively.On this account it was difficult todiazotise these bases quantitatively.Two isomeric acylated ortho-diamines have now been prepared,which, being free from this tendency to condensation, can be con-verted without loss into their corresponding diazoimides. Theaebases, 44 enzenesulphonyl-3 : 4-tolylenediamine (formula 11) ani118 MORGAN AND SCHARFF:3-benzehesulphonyl-3 : 4-tolylenediamine (formula V), on treatmsntwith nitrous acid give rise respectively t o 4-benzenesulphonyl-3 : 4-tolylenediasoimide (formula 111; m. p. 118-119O) and 3-benzen.e-sulphon&3 : 4-tolylenediazoimide (formula VI, m. p. 150-151O). I neach case the product, which is obtained in quantitative yield,consists of one isomeride only.As regards the orientation of itssubstituents, the former of these diazoimides corresponds withZincke and Lawson's less fusible a-acetyl-3 : 4-tolylenediazoimide(AnnuZen, 1887, 240, 119), and the latter isomeride with the morefusible P-acetyl-3 : 4-tolylenediazoiniide. In the present instance itie, of interest to note that the fusibility is reversed, the &(or 3-ben-zenesulphony1)compotnd being the less fusible. The more fusiblea-(or 4-benzenesulphony1)isonieride is a labile modification, and onprolonged boiling in benzene or alcoholic solution it is transformedalmost entirely into the less fusible 8-isomeride. A similar exampleof isomeric change in this series of compounds has already beennoticed in the case of l-benzenesulphonyl-4-bromonaphthylene-2-diazo-l-imide, which, under comparable conditions, becomes con-verted into 2-benzenesulphonyl-4-bromonaphthylen~l-diazo-2-imide(T., 1910, 97, 1705).I n both instances the more fusible and moresoluble diazoimide changes into its less fusible and less solubleisomeride.I n the caqe of the acetyl-3 : 4-tolylenediazoimides prolonged boilingof either isomeride in alcoholic soltition leads to an equilibriummixture of the two compounds.The production of the isomeric benzenesulphonyl-3 : 4-tolylene-diazoimides is sumrnarised in the following diagram :C H,(111.) or-Isorneri;de(w. p. 118-119").I ACH,+TCH,(VI.) 13-Isomeride(m.p. 150-151").The parent nitro-base of the lower series of compounds is d-nitro-3-toluicline (m. p. 111--112°), and these experiments have inci-dentally afforded an opportunity of establishing the identity of thCONSTITUTION OF THE ORTHO-DIAZOIMINES. ART IV. 11 9nitr*l,ase produced from m-toluidine and diacetyl-2 : 5-tolylene-diainine with the preparation obtained from m-cresol by Stadeland Kolb (AnnuZen, 1890, 259, 224), who gave the melting pointas logo.EXPERIMENTAL.4-BenzenesuZphonyL3-nitro-p-toluidine (Formula I).Molecular proportions of 3-nitro-ptoluidine, benzenesulphonicchloride, and triethylamine dissolved in benzene were heated in areflux apparatus for two hours. The solvent was evaporated, theresidue extracted with N-sodium hydroxide, and the filtered solutionacidified with hydrochloric acid.The precipitate was purified bysuccessive crystallisations from petroleum (b. p. SO-100.) andbenzene. The substance separated either in transparent, amber-coloured prisms or in colourless, acicular prisms, both modificationsmelting a t 101-102° :0.1954 gave 0.1576 BaSO,. S= 11.07.C,3H,20,1N,S requires S = 10.96 per cent.In preparing 4-benzenesulphonyl-3-nitro-ptoluidine by the aboveprocess it was found that a residue of unchanged 3-nitro-ptoluidinewas left after extracting ths crude product with aqueous sodiumhydroxide. Accordingly, the condensation in dry toluene wasrepeated a t 140° in sealed tubes, when the reaction went to com-pletion and a good yield of the acyl derivative was obtained.Thissubstance behaved as an acid, decomposing carbonates, and yieldingyellow, soluble alkali salts.4-Benzenesulphon yZ-3 : 4-tolylenediamine (Formula 11).The foregoing nitro-compound (10 grams), suepended in warmwater (200 c.c.) acidified with 2 C.C. of glacial acetic acid, wasreduced by the gradual addition of iron filings (10 grams). Afterboiling for thirty minutes the solution was neutralised with calciumcarbonate, filtered hot, and the filtrate acidified with acetic acid. Abulky, white precipitate was obtained, which was purified by crystal-lisation from water or from benzene and petroleum. The substanceseparated from the former solvents in colourless, felted needles, andfrom the latter in sheaves of lustrous, colourless, silky needles,melting a t 146-147O :0.1240 gave 11.3 C.C.N, a t 20° and 757 mm.C,3R,,0~2S requires N = 10.69 per cent.The acylated diamine was readily soluble i n alcohol, but onlysparingly so in light petroleum; *it was amphoteric, decomposingcarbonates, and forming salts with either bases or mineral acids.N=10.43120 MORGAN AND SCHARFF:4-Benaenesulphorcyl-3 : 4-tolylenediaaoimide (Formula 111).The preceding base (1 gram), dissolved in 10 C.C. of 23-hydro-chloric acid, yielded forthwith a precipitate of the sparingly solublehydrochloride, separating in colourless leaflets. The mixture, dilutedto ten times its bulk, was treated at the ordinary temperature with6 C.C. of N-sodium nitrite, when the diazoimide separated as acurdy precipitate.As this product is practically insoluble in coldwater, the experiment was repeated quantitatively, when 1 gram ofdiamine yielded 1-02 grams of diazoimide, melting a t 115O, thecalculated amount being 1-04 grams.After two rapid crystallisations from alcohol or from petroleuin(b. p. 80-looo) the diazoimide crystallised in glistening, colourless,acicular prisms, showing cruciform twinning, and melting at118-119O. A mixture with the isomeric 3-benzenesulphonyl-3 : 4-tolylenediazoimide melted a t 105-108O :0.1374 gave 17.8 C.C. N, a t 1g3 and 767 mm.0.1322 ,, 0.1130 BaSO,. S=11*74.C,H,,O,N,S requires N= 15.38; S=ll.72 per cent.4-Benzenesul~7ionyl-3 : 4-tolylenediazoimide is much more solublethan its isomeride (formula VI), but when its solutions in alcohol,benzene, or petroleum are boiled for some time transformation intothe less soluble isomeride takes place, the product crystallising outin the long, glistening prisms characteristic of 3-benzenesulphonyl-3 : 4-tolylenediazoimide.The transformation product melted at148--149O, and its mixture with 3-benzenesulphonyl-3 : 4-tolylene-diazoimide melted at the same temperature. A sulphur estimationin the transformation product gave S = 12.30, the calculated amountfor a purely isomeric change being 11-72 per cent. This resultshows that in the present instance the transformation takes placewithout any elimination of the benzenesulphonyl group. I n the caseof the pair of naphthalenoid diazoimides already cited (T., 1910,ibid.), traces of moisture or other impurities promote hydrolysis, sothat the product of the change is a mixture of stable benzene-sulphonyldiazoimide and the corresponding diazoimine.N= 15-23,Preparation of 4-Nitro-m-toluidine.The melting point of 4-nitro-m-toluidine was given as 109O byStadel and KolE (Zoc.cit.), who prepared it from m-cresol, and as110-110*5° by Cohen and Dakin, who obtained it from aceto-m-toluidide (T., 1903, 83, 333). The latter melting point correspondedwith that obtained for the product (m. p. 111-112°) preparedfrom diacetyl-2 : 5-tslylenediamine (T., 1913, 103, 1399). I n srdeCONSTITUTION OF THE ORTHO-DIAZOI&fINES. PART IV. 121to confirm the identity of these preparations the base employedin the following experiments was obtained partly from m-cresoland partly from m-toluidine.Both preparations after repeatedcrystallisation from petroleum (b. p. S0-1OO0) melted a t 111-112°,and the mixed melting point, showed no depression.(1) Pron2 m-CresoZ.-Stadel and Kolb’s method of nitration(Zoc. c i t . ) was adopted, and the required 4-nitro-m-cresol separatedfrom 6-nitro-m-cresol by distillation in steam. The volatile nitro-compound was dissolved in alcohol, and treated with the calculatedamount of alcoholic sodium ethoxide. The precipitated scarletsodium salt, washed with ether until free from alcohol, was dissolvedin water and decomposed with silver nitrate. The dark red silver4-nitro-m-tolyloxide was washed with ether, thoroughly dried, andmixed with excess of ethyl iodide.An exothermic change occurred,which was inoderated by the a.ddition of dry ether. The mixturewas then boiled in a reflux apparatus for twelve hours, and thesilver iodide repeatedly extracted with ether. The collected filtrateswere evaporated t o remove ether, when the residue solidified t o acrystalline mass of 4-nitro-m-tolyl ethyl ether (m. p. 50-51°). Itwas found necessary to avoid the presence of alcohol in preparingthe above silver salt, as this solvent has a marked reducing actionon the metallic compound.The 4-nitro-m-tolyi ethyl ether (5 grams) was heated for twelveto eighteen hours a t 190-200° with 10 C.C. of alcohol and 10 C.C. ofaqueous ammonia (D 0.88). After evaporating to dryness, theresidue was extracted repeatedly with concentrated hydrochloricacid.The diluted filtrate was rendered ammoniacal, and the pre-cipitated 4-nitro-m-toluidine crystallised from light petroleum.(2) From m-Toluidiize.-Recrystallised aceto - m - toluidide (20grams) was dissolved i n 24 C.C. of glacial acetic acid, and treatedsuccessively with 74 C.C. of nitric acid (D 1-42} and 40 C.C. of con-centrated sulphuric acid. The solution was cooled if necessary, 80that the temperature did not exceed 30°, and after several hourswas poured on t o ice; the nitrated product, which separated as ayellow, crystalline precipitate, was recrystallised f lorn alcohol. Thepurified material suspended in 20 parts of boiling water acidifiedwith acetic acid, was reduced with iron filings. After boiling forthirty minutes and then adding calcium carbonate, the filtrate,acidified with acetic acid, was concentrated to a small bulk, treatedwith acetic anhydride, and the evaporation completed.The crudediacetyl-2 : 5-tolylenediamine was crystallised from hot water, andnitrated in glacial acetic acid by the successive addition of half itsweight of nitric acid (D 1-42> and the same a.mount of concentratedsulphuric acid. Hydrolysis of the nitrated product with alcoho122 MORGAN AND SCHARFF:and concentrated hydrochloric acid in equal volumes furnished4-nitro-2 : 5-tolylenediamine (m. p. 173O). The conversion of thisdiamine into 4-nitro-m-toluidine was carried out as in the previouscommunication (Zoc. cit.), but in such a manner as t o obtain acomplete diazotisation to the lrionodiazonium salt.The diamine(3 grams), suspended in 10 C.C. of glacial acetic acid saturated withhydrogen chloride, was treated with dry sodium nitrite in slightexcess. The orange-yellow hydrochloride changed in colour to olive-green, and then to light brown, the diazonium chloride being almostcompletely dissolved. Dry ether was now added, and the precipi-tated diazonium salt, which is very sensitive t o light, was rapidlycollected, washed with ether, suspended in absolute alcohol, and themixture boiled so long as the odour of acetaldehyde was noticeable.After evaporating nearly t o dryness, the residue was renderedammoniacd, and the precipitated base crystallised from petroleum(b.p. 80-looo), being thus obtained in orangeyellow spicules(m. p. 111-112°). The yield was 60-70 per cent. on the weightof 4-nitro-2 : 5-tolylenediamine.3-Benzen eszclph o n!yl-4-n,itro-m-t oluidine (Formula IT).4-Nitro-m-toluidine dissolved in dry toluene was heated f o r fivehours a t 130-140° in sealed tubes with rather more than thecalculated quantities of benzenesulphonyl chloride and triethyl-amine. The product was extracted with alcohol, the volatilesolvents evaporated, and the residue warmad with axcess ofN-sodium hydroxide. The alkaline filtrate acidified with hydro-chloric acid gave a precipitate of 3-benzenesulphonyl-4-nitro-m-toluidine, which was crystallised from benzene, and separated indog-toothed prisms melting at 137-138O :W1533 gave 0.1240 BaSO,.C,,H,,O,N,S requires S = 10.96 per cent.This benzenesulphonyl derivative dissolved readily in alcohol,and was sparingly soluble in petroleum (b.p. 50-100°), crystal-lising therefrom in fern-like aggregates of transparent, yellowprisms.S= 11.11.3-Benzenesulphonyl-3 : 4tolylenediarnine (Pormula V).The preceding nitro-compound was reduced like its isomeride, andafter removing iron oxide the product separated from the acidifiedfiltrate in colourless, felted needles. Crystallisation from benzeneor petroleum (b. p. 80-looo) gave silky, colourless needles, meltingat 134-135OCONSTITUTION OF THE ORTHO-DIAZOIMINES. PART IV. 1230-0963 gave 9.5 C.C. N, a t 16O and 748 mm.This acylated diamine is amphoteric, forming salts with eitherbases o r acids. The acid salts serve t o separate it from unchanged3-benzer~esulphonyl-4-nitro-m-toluidine (m.p. 137--138O), which isless readily reduced than its isomeride (m. p. 101-102°).N=11*40.C,3Hl,02NzS requires N= 10.69 per cent.3-BenzenesuZphonyZ-3 : 4-toZyZenediazoimide (Formula VI).3-Benzenesulphonyl-3 : 4-tolylenediamine (1 gram) was added to10 C.C. of N-hydrochloric acid, when the sparingly soluble hydro-chloride separated in colourless, nacreous leaflets. The solutiondiluted ten-fold was treated a t the ordinary temperature withA7-sodium nitrite, when the diazoimide separated immediately as acurdy precipitate, the yield being quantitative. The dried product(m. p. 147O) was crystallised from alcohol, in which it is much lesssoluble than its isomeride ; it separated in lustrous, colourless prismsoften more than 1 cm. in length, and melted a t 150-151O:0.1346 gave 18 C.C. N, at 15O and 758 mm. N= 15.71.0-0983 ,, 0.0862 BaSO,. S=12*04.C,3H,10,N,S requires N= 15.38; S.= 11.72 per cent.3-Benzenesulphonyl - 3 : 4 - tolylenediazoimide crystallised frombenzene in lustrous, tabular prisms; its mixed melting point withthe isomeric 4 - benzenesulphonyl - 3 : 4 - tolylenediazoimide wasWhen warmed to 80°, both the isomeric benzenesulphonyl-3 : 4-tolylenediazoimides manifest an odour resembling that of liquorice.I n this respect they resemble the isomeric acetyl-3: 4-tolylenediazo.imides.105-108°.The authors desire to express their thanks to the b e a r c h GrmtCommittee of the Royal Society for a grant which has partlydefrayed the expenses of this investigation.ROYAL COLLEGE OF SCIENCE FOR IRELAND,DUBLIN

ISSN:0368-1645    

DOI:10.1039/CT9140500117

出版商:RSC    

年代:1914

数据来源: RSC

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124 CHATTAWAY AND CONSTABLE :XV1 I.--Deriziutives of p-lodomiline.By FREDERICK DANIEL CHATTAWAY and ALFRED BERTIE CONSTABLE.THE ease with which chlorine and bromine substitute aromaticamines has led to a very complete knowledge of the simplerderivatives which they form, but very few of the correspondingiodine compounds have been prepared on account of the difficulty ofeffecting iodine substitution, and the readiness with which the iodo-anilines decompose.The action of iodine on aniline was naturally exammined when thelatter compound began to attract attention towards the middle oflast century, and Hofmann (Annulen, 1848, 67, 61; Chem. News,1864, 9, 163) thus obtained a product which, however, he did notisolate in a pure state. I n spite of the attempts of Rudolph (Ber.,1878, 11, 78), who obtained a mixture of mono- and di-iodoanilineby the action of iodine on phenylated white precipitate, and ofComstock and Kleeberg (Amer.Chem. J., 1890, 12, 493), whoprepared p-iodoformanilide by the action of iodine on silver form-anilide, little progress was made by the use of the element itself,and it was not until iodine chloride was employed that an iodo-aniline was obtained in satisfactory amount by direct substitution.Brown (Phil. Mag., 1854, [iv], 8, 201) appears t o have been thefirst to employ iodine chloride as a substituting agent, althoughhe only tried its action on some complex vegetable acids. Stenhouse(T., 1864, 17, 327), much later, allowed i t to act on aniline itself,and naturally obtained a black tarry product, from which nothingcould be isolated in a pure state. Michael and Norton (Ber.,1878, 2, 107) were the first to employ the reagent satisfactorily.They led the vapour of iodine monochloride into a solution ofacetanilide in glacial acetic acid, and obtained thus a solution ofp-iodoacetanilide. They also obtained in a similar manner fromaniline itself a dark-coloured product, from which 2 : 4-di-iodo-and 2 : 4 : 6-tri-iodo-aniline were isolated.Our knowledge of the subject beyond this point is very scanty,and is confined to a few isolated anilides, some obtained as by-products. Thus Dyer and Mixter (Amer.Chem. J., 1886, 8, 349)found that iodine had no action on oxanilide dissolved in glacialacetic acid, but that on adding concentrated nitric acid, violentaction ensued, and a di-iodo-oxanilide was formed t o a small extent.In this paper the conditions necessary t o obtain a good yield ofpiodoacetanilide, and to prepare from it p-iodoaniline, are given.A number of the simpler derivatives obtainable from the latter arealso describedDERlVATIVES OF P-IODOANILINE.125Preparation of p-lodoacetanilide, I/-\NH*CO*CH,. \- /For this purpose it is best to employ iodine monochloride dis-solved in acetic acid. Such a solution is conveniently prepared bythe action of chlorine on finely powdered iodine suspended in glacialacetic acid. The following procedure gives a good result. Finelypowdered iodine (127 grams) is added to glacial acetic acid (150c.c.), and chlorine is passed through the suspension, the latterbeing well shaken until the appearance of small, orange-colouredcrystals of iodine trichloride, which fall as a sandy precipitate,shows that all the iodine has been converted into iodine mono-chloride. The solution must now be thoroughly shaken withsufficient finely powdered iodine t o react with the small quantityof the trichloride formed, and when this completely disappears thesolution is ready for use.To 135 grams of acetanilide in 150 C.C.of glacial acetic acid asolution of iodine monochloride, prepared as above, containing127 grams of iodine, is added with continual agitation. Someheat is developed, and a dark brown solution is formed, whichremains clear for a few moments, but as the reaction proceedspiodoacetanilide crystallises out.After twelve hours two litresof water are added to precipitate the anilide. This is collected,washed with water and then with dilute alkali, and finallycrystallised from about 400 C.C. of alcohol. After three crys-tallisations the piodoacetanilide is obtained in large, colourlessrhombs, melting a t 184O. The yield is about 90 per cent. of thetheoretical. In these circumstances the iodine alone substitutes,the chlorine combining with the displaced hydrogen, and not sub-stituting t o any recognisable extent.Preparation of p-Zodoaniline, I/-'NH,.pIodoaniline is best obtained from the acetyl compound byhydrolysing the latter with alcoholic sodium hydroxide. Onehundred grams of piodoacetanilide (1 mol.) are added to a solutionof 30 grams (2 mols.) of sodium hydroxide in 500 C.C.of alcohol, .and the mixture is boiled gently for twelve hours. On pouring thecooled mixture into three or four times its bulk of water, theaniline separates. p-Iodoaniljne, when obtained in this way, isnearly pure, but has a slight, brown colour. This may be removedby crystallisation from alcohol, in which the aniline is very soluble,or by distillation in a current of steam. When pure it is colourless,and melts a t 61-62O. It may be heated for some time to 190°without decomposition, but if heated above 200° it decomposes.\--126 CHATTAWBY AND CONSTABLE :p-Iodopropionanilicie, H- CO*C,H,. \-/This compound is formed with considerable evolution of heatwhen p-iodoaniline is added to an equivalent quantity of propionicanhydride.It crystallises in two polymorphic forms. When asolution in alcohol is cooled a liquid is obtained, which, on beingtouched with a glass rod, deposits an unstable modification; thisseparates in minute, colourless needles, forming a felted mass. I na few minutes the unstable form transforms into the stable modifi-cation, the felted mass crumbling away, and the stable form fallingto the bottom of the beaker as a shower of small, granular crystals:CgHi,ONI requires I = 46.15 per cent.0.2101 gave 0.1787 AgI. 1=45.97.Benzo-piodoanilide, I/-\NH*CO*C,H,.This compound is easily prepared by the action of benzoyl chlorideon piodoaniline in the presence of dilute aqueous potassiumhydroxide.It crystallises from alcohol in colourless prisms, meltinga t 222O:\/0.2144 gave 0.1573 AgI. 1=39*65.C,,H,,ONI requires I = 39.29 per cent.NO,o-Nitro benzo-p-iodoanilide, I/-\N H *CO/-\ \-/ \-/ -This crystallises from alcohol, in which it is very sparingly soluble,0.2646 gave 0.1681 AgI.in long, thin prisms, with a faint yellow tinge, melting a t 208O:I=34*34 per cent.C,,Hg03N,I requires I = 34-48 per cent.m-Nitro b enzo-piodoanilide.This derivative crystallises from alcohol in long, pale yellow0.2115 gave 0.1344 AgI. 1=34*35.’ prisms, which melt a t 202O:C,,H,O,N,I requires I = 34-48 per cent.p-Nitro benso-piodoanilide.This substance is even less soluble in alcohol than the correspond-It cryatalliaes in very slender, pale yellow, ing meta-compound.needleshaped crystals, melting at 269O DE HIVATIVES OF P-IODOANILINE.1270.2069 gave 0.1315 AgI. I=34*35.C,3H,03N21 requires I =34.48 per cent.The nitrobenzo-piodoanilides are best prepared by grindingtogether equivalent quantities of the corresponding nitrabenzoylchlorides and piodoaniline, moistening with a little ether tofacilitate interaction, and adding a concentrated solution of sodiumcarbonate from time to time until, on keeping, the liquid remainsdefinitely alkaline.I/-\N H-CO-CH,*C~H,. \-/ Yhenylace to-p-iodoa~~ilide,This compound is obtained by the action of phenylacetyl chlorideon piodoaniline dissolved in ether in the presence of an equivalentamount of pyridine; it crystallises from alcohol, in which it ismoderately soluble, in small, needle-shaped crystals, melting a t200° :0.2265 gave 0.1562 AgI.I=37*27.C1,Hi20NI requires I = 37.65 per cent.This substance is easily prepared by heating together a mixtureof equivalent quantities of piodoaniline and phthalic anhydride toabout 180O. 'It is very sparingly soluble in alcohol, and sparinglyso in glacial acetic acid. It crystallises from the latter in long,slender, colourless prisms, melting a t 235O. The compound originallyprepared by Gabriel ( B e y . , 1878, 11, 2261) was evidently not suffi-ciently purified, as he gives 227-228O as its melting point.o-Nitro b enzaldehyde-p-iodophenylhydrazone,NO,I/-\NH* N : c d7 \-/ \-/ *This compound, prepared from p-iodophenylhydrazine (Neufeld,Annalen, 1888, 248, 98), crystallises from alcohol, in which it issparingly soluble, in deep garnebred prisms, which melt anddecompose at 196O:0.2120 gave 0.1355 AgI.1=34*54.C1,Hl,O2N3I requires I = 34.58 per cent128 CHATTAWAY AND COSSTABLE ;m-Nitro b enzalde h yde-p-iodo ph en yl hydraz o n e .This compound is sparingly soluble in alcohol, giving a deeporange-coloured solution, from which i t crystallises in clusters ofsmall, bright, scarlet prisms, melting and decomposing a t 148O :0.2059 gave 0.1326 AgI. I=34.81.C,,H,,O,N,I requires I = 34-58 per cent.p-Nitrob enzaldehyde-p-iodophenylhydrazone.This crystallises from alcohol in slender, garnet-red prisms, which0.2363 gave 0.1517 AgI. 1=34*70.melt and decompose a t 158O:C,,H,,0,N31 requires I = 34.58 per cent.C'innamaldehyde-p-iodopheny lhydrazone,l/-\N K ON: C H C I1 : CH C,Trf,.\-/This compound crystallises from alcohol in bright yellow needles,0-2049 gave 0.1379 AgI. I=36*37.which melt and decompose at. 1 4 0 O :C,,H,,N21 requires I = 36.46 per cent.This azo-compound was obtained by combining diazotised p-iodo-aniline with phenol in alkaline solution. It crystallises from alcoholin light, golden-brown plates, melting a t 172O, which, when dry,appear maroon coloured with a golden-yellow lustre :0.2009 gave 0.1450 AgI. 1=39.01.C,,H,ON,I requires I = 39.17 per cent./-\\-/\d' \-/ p-lodob enzeneazo-&naphthoJ, I/-\N :N/ .' 'OHThis compound was similarly prepared from 8-naphthol. It isonly very sparingly soluble in boiling alcohol, but is moderatelysoluble in boiling acetic acid, from which it crystallises in dark redprisms wit,h a greenish, metallic lustre, melting at 178O:0-1941 gave 0.1213 AgI.I=33*78.C,,H,,0N21 requires I = 33-93 per centDERIVATIVES OF P-TODOAWILINE. 129p-lodoaniline reacts readily with ethyl or methyl chloroformate toform the corresponding carbanilate. The reaction is best carriedout by mixing an equivalent amount of the chloroformate with theaniline dissolved in a little dry ether, and, when the vigorous actioiihas moderated, adding enough pyridine to combine with thehydrogen chloride formed, then driving off the ether by heatingfor a short time on the water-bath. After tlioroughly washing theproduct with dilute hydroch1or;ic acid, it is recrystallised fromalcohol.E t iiyl p-lodo phenyl car bnma t e, I/-\ , ,i Y H.CO,*C,Ff,.This ester crystallises from alGoho1, in ~ : ~ i c h it is very soluble, in0.1943 gave 0.1570 AgI.1=43*67.slender, colourless, prisms, melting a t 1 1 7 O :C~13100zNI requires I = 43-61 per cent.Methyl p-lodophenylcarbamate, .I/ --\?z €1. C(.),*CH,. \-/This crystallises from alcohol in colourless plates or long, flattened0*1610 gave 0.1371 AgI. 1=46*03.C8H80zNI requires I = 45.82 per cent.pIodoaniline also reacts readily with ethyl oxalate o r ethylmalonate when the substances are heated together, forming thecorresponding anilic esters or anilides. The anilic ester or anilideis obtained in greater amount, zccording as the ester or the anilineis in excess.They can easily be separated, as the anilides arealmost insoluble in alcohol.prisms, which melt a t 142O:Ethyl p-lodo-oxanilate, I/-'NH*CO* CO,*C,H,. \-/This ester is almost exclusively formed if piodoaniline (1 mol.)is heated for about ten minutes t o 170° with five times its weight(8 mols.) of ethyl oxalate. It crystallises from boiling alcohol, inwhich it is moderately soluble, in colourless, crystalline plates,melting a t 153O:0,1678 ga63 0.1238 AgI. 1=39*88.C,oH,,03NI requires I = 39.78 per cent.s-Di-piodomalolzanilida I/-\N H-CO CH,* CO* N H/-\I,\-/ \-/pIodoaniline (1 mol.) was dissolved in three times its weight ofethyl rnalonate (4 mols.), and the liquid heated to 170° for tenVOL.cv. 130 DERIVATIVES OF P-IODOANILIN~:.minutes. On diluting the hot liquid with alcohol and cooling,s-di-p-iodomalonandide separates. A yield of 20 per cent. of thetheoretical, calculated from the weight of aniline used, was obtained.It crystallises from boiling glacial acetic acid, in which it is sparinglysoluble, in slender, colourless needles, melting and decomposing at267O :0.2009 gave 0.1861 AgI. 1=50.07.C1,H1202N212 requires I = 50.17 per cent.Ethyl p-lodonzalonatailat e , I/-'\N I i * CO-CH2*C0,*C2H,. \--/This compound was deposited by the filtrate from t h e previouslydescribed compound, after concentration. A yield of about 50 percent. of the theoretical, calculated from the weight of aniline used,was obtained.It crystallises from boiling alcohol, in which i t isreadily soluble, in colourless, crystalline plates, melting a t 120° :0.2394 gave 0.1690 AgI. 1=38*15.CllH120,NI requires I = 38.11 per cent.It has been shown by Chattaway that when carbamide is heatedwith any arylamine, ammonia is eliminated, and a monoaryl- anda s-diaryl-carbamide are produced, the former or the latter beingobtained in preponderating amount according as the carbamide orthe base is present in excess. p-Iodoaniline reacts with carbamideas do other arylamines.p-Iodoaniline (I mol.) was mixed with carbamide (7 mols.), andthe mixture heated on an oil-bath at 180° until ammonia ceased tobe freely evo1vq.d. The light brown solid thus produced was2owdered and extracted first with water and then with boilingalcohol. The residue, which consisted of s-di-p-iodophenylcarbamide,amounted to 60 per cent. of the theoretical obtainable from theaniline used. s-ni-p-iodophe.l.LyZcarbanzide is insoluble in alcohol,and almost insoluble in glacial acetic acid, but is moderately solublein boiling nitrobenzene, from which it crystallises in small, colour-less, needle-shaped crystals, which remain unmelted at 350O. (Found,I = 54-81.This compound was first obtained by Vittenet (Bull. SOC. cham.,1899, [iii], 21, 305) by heating piadoaniline with a solution ofcarbonyl chloride in toluene.Cl3Hl,ON2I2 requires I =54.71 per cent.THE DISTILLATION OF COAL IN A VACUUM. 131p-lodophemylcarbam2.de, I/-\NH*CO*NH,. \-/This compound is deposited by $he alcoholic extract from theproduct previously described after concentration. It is readilysoluble in boiling alcohol, and crystallises from this solvent incolourless plates, which remain unmelted a t 300° :0.2330 gave OZ2089 AgI. 1=48.46.C,H,ON,I requires I = 48.44 per cent.OXFOILD.UNIVERSITY CHEMICAL LABORAI ORY

ISSN:0368-1645    

DOI:10.1039/CT9140500124

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

THE DISTILLATION OF COAL IN A VACUUM. 131XVI1I.-The Distillation qf Coal in a Vacuum.By MAURICE JOHN BURGESS and RICHARD VERNON WHEELER.IN the course of an investigation into the nature of coal, the effecthas been tried of distillation a t different temperatures and underdifferent conditions. Some account of the results obtained hasalready been communicated to the Society (T., 1910, 97, 1917;1911, 99, 649; 1913, 103, 1704). In the earlier stages of thisinvestigation, during the year 1909, distillations of coal weremade a t low temperaturm in a high vacuum, the main object beingto examine the liquid products. The gmeous products of distilla-tion in a vacuum were also studied, and the results obtained formthe subject of the present paper.It has already been shown that it8 the temperature of distillationof coal is increased from 500° to l l O O o the percentage of hydrogenin the gases evolved increases, whilst the percentages of methaneand ethane decrease, a decomposition point, marked by a rapidevolution of hydrogen, occurring at about 750O.Below 450° i twas stated (Zoc. cit.) that ‘‘ ethane, propane, and, probably, highermembers of the paraffin series form a large percentage of thegases evolved.”When coal that has been finely pulverised and thoroughly driedin air at 107O is exhausted a t room temperature, “occluded”gaees in small quantity can be pumped off. These gaees, unlike theoccluded gases that can be obtained, sometimes in large volume,from newly-won, undried cod, consist largely of carbon dioxideand carbon monoxide.On raising the temperature of the coal during exhaustion, thesuccession of events is^ as follows :l i 132 BURGESS AND WHEELER :Occluded or " condensed " gases (unextractable at atmospherictemperature) continue to be removed in small quantity up to 150°or 200O. These gases are mainly the paraffin hydrocarbons, thehigher members predominating.At about 200° there is a copious evolution of water (small quan-tities of gas being also evolved), and water continues to make itsappearance at successive stages in the distillation up to 45UO-thehighest temperature employed in this series of experiments.Thiswater, as has been pointed out in a previous paper, must be waterof constitution. The gases evolved during the period of mostrapid formation of water contain a high percentage of the oxidesof carbon.Between ZOOo and 300° decomposition occurs of some sulphur-containing organic conipound, for the gases evolved during thatperiod contain a considerable proportion of hydrogen sulphideand tarnish mercury.This decomposition, which begins a t about270°, is practically completed a t 300O. Simultaneously with thehydrogen sulphide the gases contain a considerable proportion ofthe higher olefines, the evolution of which does not, however, ceaseor fall off until a temperature of 350° is reached.Liquids other than water begin to distil a t about 310°, a t whichtemperature a thin, reddish-brown oil appears. There is nomarked evolution of gas a t this temperature, and i t seems probablethat the oil is not necessarily a product of decomposition, but maybe liquated out of the coal conglomerate.A decomposition point occurs a t about 350°, there being thena rapid evolution of gas and much viscid oil formed.Decomposi-tion then continues with increasing rapidity as the temperature isr aisecl .The mixtures of gases evolved a t the different temperatures arevery complicated, containing as they do hydrogen sulphide, ca.rbondioxide, ethylene and the higher olefines, carbon monoxide,hydrogen, and the paraffin hydrocarbons up to and includingpentaneThe presence or absence of benzene vapour could not bedefinitely established owing to the difficulty there is in estimatingit separately from the higher olefines*; but neither benzene norits homologues could be detected in the liquid products of distilla-tion in a vacuum up to 450°, so that the presence of the vapoursamongst the gaseous products is extremely doubtful.* I n the analysis of these mixtures of gases the reagent used for estimatingbenzenetogether with tne higher olefines, sepaisately' from ethylene, was concentratedsulphuric acid (D 1.84).Treatrneiit for a short tiriie with this reagent (the densityof which was wrongly stated to be 1.9 in a previons paper) removes benzene and t h ehigher oletines together, leaving ethylene practically untonchedTHE DISTTLLATION OF COAT, IN A VACUUM. 133Of the paraffin hydrocarbons, besides methane and ethane,propane and butane were isolated by fractionation with liquid airand solid carbon dioxide dissolved in ether, and the presence ofpentane established by explosion analysis.It is impossible in a mixture of more than two of the membersof the paraffin series to calculate the percentage of each constitu-ent present, but on explosion with excess of air the value of theratio CIA (contraction on explosion : absorption by potassiumhydroxide, that is, carbon dioxide formed) gives some indicationof their nature; chus the value of the ratio is for methane 2-00and f o r ethane 1.25, so that if a mixture of the paraffins gives onexplosion analysis a ratio CIA lying between 2.00 a.nd 1.25, it isgenerally safe t o say that both methane and ethane are containedin the mixture, and it is usual t o calculate the analysis on theassumption that no higher inember is present.It must be bornein mind, however, that the same analytical results are given onexplosion by a mixture of equal volumes of methane and propaneas by pure ethane.A method of calculation which gives, perhaps, a better idea ofthe nature of the gases present than does the ra.tio C / A is basedon the following considerations :41 volumes of any mixture of paraffin hydrocarbons containm CH, groups and n CH, groups (in the case of methane n=O).The carbon in the mixture of paraffins is equal to the carbondioxide produced on explosion (is equal to the absorption, A , bypotassium hydroxide after explosion); and if the letter G be takento represent the contraction on explosion, the hydrogen in themixture of paraffins is given by the expression 2/3(2.4 + 2C).From these two relationships we get:wz + n = carbon = A ,andwhence m=1/3(2C-A),and 72 = 2 I 3 (2 A - C) .volumes of the paraffins present, whatever their composition, so tbat :4nz + 2n = hydrogen = 2 / 3(2A + 2C) ;Now m, the number of CH, groups, givee also the number ofVolume of paraffins, Tr,=1/3(2Cf-9) .. . (1)The number cf CH2 groups per 7 1 ~ volumes of the paraffins isgiven by the equation:n = d - V . . . . . . , (2)So that n / V , the number of CH, groups per unit volume of theparaffins, can be obtained by means of these equations; or it canbe calciilated directly from the relation :. . . . . . I b - 2 ( 2 A - C ) _ - ~V 2C-I34 BURGESS AND WHEELER :The value n / V is in several ways more convenient than theratio ( ! / A usually employed, for it shows at a glance the averagenumber of CH, groups in the mixture of paraffin hydrocarbonsanalysed, and, in conjunction with the determination of V , enablesa record of the volume of the paraffins and a statement as to theirnature t.0 be made without entering into any hypothetical calcu-lation of the percentages of individual members present.Thevalue n / V for methane is, of course, 0; for ethane it is 1, forpropane 2, and so on.The higher paraffins mostly appear at the lower temperaturesof distillation, the range 100-300° being attended by thegreatest percentage evolution. Above 350°, the decompositionpoint of part of the coal substance, the percentage of methaneincreases, and that of the higher hydrocarbons decreases.It is conceivable that the paraffin hydrocarbons obtained byexhaustion from coal a t temperatures between ZOOo and 300° (thatis, below the decomposition point observed) are present as suchin the coaI, being held in a manner similar to, but more forciblethan, '' occluded '' methane at the lower temperatures.The factthat there is a simultaneous evolution of olefines, however, makesit more probable that both classes of hydrocarbons arise from thethermal decomposition of a solid paraffin or similar long-chaincompound.EXPERIMENTAL.The apparatus employed for the vacuum distillations underwentseveral modifications during the course of the research.Its finalform is depicted in Fig. 1. As will be seen from this diagram, theneck of the distillation retort (a round-bottom flask of Jena hardglass) pointed vertically downwards into a receiver attached by aground-glass joint. By distilling the coal in this manner refluxcondensation of liquid produck was avoided, and their thermaldecomposition prevented or minimised. A second and, in someexperiments, a third receiver was interposed between the firstand an autoniatically-acting mercury pump, fitted with twoSprengel tubes, used for withdrawing the gases as they wereevolved from the coal, The receivers nearest the pump were keptcooled throughout the distillations by a solution of solid carbondioxide in ether, or, in some experiments, by liquid air.Thewide-bore tap on the neck of the retort enabled the distillationsto be interrupted at different temperatures, and the condensing-tubes changed, without admitting air to the coal.The capacity of t.he retort in the experiments described in thispaper was such as to onable 200 grams of coal to be distilledTHE DISTILLATION OF COAL IS A VACUUM. 135the retort being filled to thO neck. In later experiments a retortcapable of holding about 1& kilos. has been employed.Method of Ezpwiment.-Fine dust obtained by pulverising nutcoal was employed; in som0 cases after drying at 1 0 7 O duringthree hours before use, in other cases without drying,The whole apparatus having been rapidly exhausted by meansof a Qeryk oil pump, thO last traces of air were removed a t atmo-spheric temperature by the Sprengel pump.When undried coalwas used, " occluded" gases continued to be pumped off forseveral days a t atmospheric temperature. These gases were, insome experiments, collected in fractions over successive periods oftime, and the fractions analpsed separately.All occluded gases having been removed at atmospheric tem-F:G. 1. F I ~ . 2.2'0 gan holderElcperature, an electric resistance furnace surrounding the retort wasgradually raised in temperature to looo, and exhaustion continuedat that temperature until no more gases could be pumped off,The temperature was then further raised, gradually, by 50° orlooo, and all the gases at this higher temperature collected. Thismode of procedure, which enabled decomposition points to bedetected, was followed up t o a temperature of 450°, each successivestage in the heating being maintained until no further gases wereevolved, and the condensing tubes being changed at each stage.The mercury pump used was rapid in its action, and, evenduring the period of maximum evolution of gases, did not allow136 BURGESS AND WHEELER :the pressure in the retort to fall below 20 mm.For the collectionof the comparatively large volumes of gases evolved at the highertemperatures the device shown in Fig. 2 was used, the globe A ,filled with mercury, being a, receiver from which the gases couldbe transferred to a gas-holder containing a mixture of equal partsby volume of glycerol and water.Each experiment lasted continuously during from four to eightweeks.Results of E’xperiments.-O*le or tv70 typical experiments onlyof the many that have been carried out need be recorded.Severaldifferent varieties of bituminous coal have been used, but noimportant differences have been observed in their behaviour onheating or in the products, whether gaseous or liquid, of theirdecomposition. The composition of the occluded gases, it is true,varies with the kind of coal and with its previous history (forexample, with the length of time since it was niined), but a studyof the occluded gases is but an incidental part of this research,and has, moreover, already received the attention of numerousinvestigators.The first experiment t o be described wm made with a sampleof Silkstone (bituminous) coal in the form of fine dust, obtainedby pulverising about 50 kilos.of washed “nuts,” and had beenpassed through a, 240-mesh sieve. This coal was from the sameseam as coal A of our previous work. The dust was not driedbefore use, and gave off a considerable volume of occluded gaseson exhaustion at atmospheric temperature. When these gases hadbeen removed the coal was heated to looo, exhaustion beingcontinued.Gases Evolved at looo.The volume of gases evolved a t looo amounted to 34 C.C. perTheir composition was as 100 grams of coal, measured a t N.T.P.follows :CO, ................................ 6-70 per cent.0, ................................. 1.66 ,,C, H, ...............................0 *85 , ,C,H,(n > 2) ..................... 1 *30 , ,CO .................................... 1.40 ,,H, .................................... 190 , ,CnH2n+Z .......................... 84 -55 , ,The walue n/V for the paraffins was 2.21, showing the presenceof homologues higher than propane.Gases Evolved at ZOOo.At 200° 65.5 C.C. per 100 grams of coal were collected. Acomplete analysis was made of a portion of this gas, and thTHE DISTILLATION OF COAT, IN A VACUUM. 137remainder passed into. a condensing apparatus surrounded by asolution of solid carbon dioxide in ether, whereby a temperatureof about -80° waa obtained. A portion of the gases (about7-5 per cent. of the total volume evolved from the coal at 2 0 0 O )liquefied a t this temperature.This gas gave on explosion analysisa ratio C/A =0*875, with a value' 12/ V=3*00, showing it to bebutane.The a.nalysis of the total gas evolved at 200° was:CO, ............................... 8-85 pvr relit.0, ................................ 0.70 ,,CTH4 ........................... 0.86 ,)C1&H2,& ............................ 2.90 ,) cot. .............................. 2 -60 , y11, .................................. 2-75 ),C,aH2rr+d .......................... S1*OO ,,The paraffins, which include the butane determined separately,had a; value n/ IT= 1-84.Gases Evolved qt 300O.The temperature of the coal was now gradually raised t,o 300'.There was no further evolut'ion of gas until a temperature ofabout 270° was reached, the gases then evolved tarnishing badlythe mercury over which they were collected.Heating and exhaustion were continued during two days, thetemperature being maintained a t 300O.Towards the end of theheating the gases evolved ceased to, ta.rnish mercury. Altogether,58.5 C.C. per 100 grams of coal were collected.Butane wa,s isolated from the gases by liquefaction, as in thecase of the gases evolved a t 2 0 0 O . The analysis of the total gasevolved showed :35-35 per cent. CO, and H,S .........C,H, .................. 0-55 .. C,H, ................. 1-05 .. C, H2?% ................. 1 8 '8 5 , . CO .................. 10.50 .. H, .................... 13.35 .. ClrH218+? ............. 18-85 ,,The valoe v / V flw t h e paraffins was 1.43.Decompositicn of eome part, or" the coal substance had obviouslytaken place between 270° and 300O; for, although the volume ofgases evolved was not large, their composition was very differentfrom that of the gases evolved below 2 0 0 O .No' separate estimationof the percentage of hydrogen sulphide present was made, but ibsprmence in considerable quantity was indicated by the yellowcolour imparted ' t o the' potassium hydroxide solution used forestimating carbOn dioxide138 BURGESS AND WHEELER :Gases Evolved at 350° and at 400O.On raising the temperature of the coal above 300° a rapidevolution of gas took place between 320° and 350°, and, aftermaintaining the temperature during eight days a t 350°, 985 C.C.of gas per 100 grams of coal were collected.The temperature of the coal was then gradually raised to 400°,and exhaustion continued at that temperature during sixteendays. Four litres of gas per 100 grams of coal were collected.The analyses of the gases collected at 350° and at 400° were:H,S ..................... co, ....................C,H, .....................C,H, ....................C,H, ..................co.......................H, ......................CnHm+2 ...............At 350".1.7020.950-151.9017-903'401.5 *3537'22A t 400".0 -702 -85trace2 -356.153.4036-9046.55The value of n / V for the paraffins was, for the gases obtainedat 350°, 0.311, and for those obtained at 400°, 0.302.Fractionation of the Gases by Liquid Air.-An experimenttypical of those in which fractionation by liquid air was resortedto was made with the Silkstone coal in the form of dust thatpassed a 1.00- and remained on a 150-mesh sieve.The dust wasdried a t 1 0 7 O in air before being put into the retort.Occluded gases having been removed, heating was carrieddirect to 340° (that is, just to the decomposition point of thecoal). Two main fractions of the gases were obtained: (a) gasescondensed by liquid air during distillation, and ( 6 ) gases notcondensed by liquid air.The uncondsnsed gases consisted mainly of carbon monoxide,hydrogen, methane, and nitrogen. The condensed gases were boiledinto a receiver, and treated in the following manner: the receiverwas cooled by a solution of solid carbon dioxide in ether, andfractions taken a t different pressures, thus :FriuAio11 KO.i. Withdrawn uuderFraction No. it.Fraction No. iii.Fnlction No. iv.Fractioii No. v.9 7 7 ,2 2 9 9* 2 9 . Receiver at atmospheric2 ) 9 7 :: 'z8 z::} teeipernture.Part of the last fraction (No. v.) showed a tendency to condenseto a mobile liquid at atmospheric temperature under slightpressureTHE DISTILI,ATION OF COAL IN A VACUUM.The analyses of these fractions were as follows:(i. 1Per cciit.CO, a d H,S ........ 8 1-00C2H, ..................... 0 -4 0C,H, ..................... 0.95C, H ................ 5 -2 5 co ........................ 0 9 5H, ....................... nil.C,, Hyz+2 ............. 8 -7 5n/V for paraffins ...... 1.93(ii )Per ct lit.70.050.350'4515-100.90nil.11.051'74(iii. )Per cent.48 000.650.957 .oo1.60i l i l .39TO2 *35(iv.)Per cent.8-100.751-107.451.50nil.82.452.77139(v- 1Per ccnt.4.10nil.1'7510.201.50nil,82.453.00It will be noticed that analysis No. iv. adds up to more than100 per cent. Occasionally, particularly with gases obtained fromcoal a t 200°, it has been found that, the volume of gases (assumingthem to be paraffins) given by explosion analysis has caused thecomplete analysis to add up to slightly more than 100. This resultis, so far as can be ascertained, due t o the fact that minute tracesof gas in the mixture of paraffins had a tendency to condense toliquids under pressure, so that in transferring them over mercuryfrom one part of the aiia.lysis apparatus to another some condensa-tion may have taken place and a slightly greater volume of gasesthan appeared on measurement burned during the explosionanalysis.Gases Evolved at 400O.The gases were fractionated with liquid air as before.Theportion uncondensed consisted mainly of carbon monoxide,hydrogen, and methane. The gases condensed by liquid air weretreated in the same way as those obtained at 340°, six fractionsbeing taken as follows:Frsztion No. i. Withilratin underFraction No. ii.Fraction No. iii. Y , 9 23 ) $ 3Fraction No. iv. 7 . 9 , 9 ' 'ij \ nrceiver a t atinospliericFraction No. v.Fraction No. vi. Last ;t'aces of ;:wlily c&dcusible gases. tc'i'I'erature'The analyses of these fractions were :(i. 1Per rent.CO, and H,S ......... 8.65C,H, ................... 0 60CzH4 .................... 7.75C,H,, ................ 3 90 co ...................... 3.35H, ....................... nil.C,Hp+% i...... ...... 69.90n/V for paraffins ...... 0.59(ii.)Per cell t.7 -000'400 *459-052 -50nil.77-100 *95(iii )Per ceut.4 -500.455 *0515.102 20nil.69.751.28(iv.) (v.) (vi.)Per cent. Percent. P1-r cent.0.70 1-65 11.800.60 nil. nil.0.50 0.65 2 0535.75 38-90 38-650.40 0'45 1-30nil. iiil. nil.60.80 55-85 41-852-00 2-46 3.65In other experiments, details of which need not be given, differen140 JONES APU’D WHEELER : THE COJIPOSITION OF COAL.boiling fractions of the liquefied gases were taken, reliquefied, andfractionated several times. I n this manner i t was possible to makea nearly complete separation of the paraffin hydrocarbons, and t oestablish the presence of all members up t o and including pentaneESRBIEALS,__ - - - _. - __ - - CUMBERLASD

ISSN:0368-1645    

DOI:10.1039/CT9140500131

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

140 JONES APU’D WHEELER : THE COJIPOSITION OF COAL.x I x . - Th e Coinposit ion Coa,Z.By DAVID TREVOR JONES and RICHAKD VERNON \VHF,ELF,P,.THE methods most promising in results t h a t have been appliedtowards attempting to elucidate the question of the chemical com-position of coal have been either to treat the coal with differentsolvents, in the hope of being able to extract some simple substancetherefrom, or to distil the coal destructively under various con-ditions in order to examine the products of decomposition.The method employed t o obtain the results described in thepresent paper was that of destructive distillation of untreated coalin a vacuum a t a low temperature, in the manner already described.Recently Pictet and Bouvier (Compt. relid., 1913, 157, 779) havepublished a preliminary note regarding experiments that they havecarried out, which are practically identical in character with ourown.The results obtained by these investigators differ, however,from ours in sevel-al importmt respects which will be discussedlater.It may be remarked a t the outset that the destructive distillationa t low temperatures of coal in its entirety cannot be expected toreveal the nature of all the various classes of compounds thatcompose the coal substance. I n previous papers it has been shownthat only the (( resirous subst mces ” in bituminous coals decomposeto any great extent a t temperatures below 500O. It is the “ resinoussubstances” only, therefore, in the coal conglomerate that must beregarded as having undergone examination by the method of attackdescribed in the present paper.The work on which we are atlpresent engaged, namely, that of destructive distillation in a vacuumof the separate portions into which coal can be divided by thesolvent action of pyridine and chloroform, will, it is hoped, enableconclusions to be drawn as t o the character and composition of the“ humus substances ” in the coal conglomerate as well as of the“ resinous substances.”Bituminous coals, wllen distilled in a vacuum (5 to 40 mm.) a ttemperatures up t o 430°, yielded, besides gaseous products andwater, about 6.5 per cent. of their weight of tar. On distillinJONES AND WHEELER: THE COMPOSITION OF COAL. 141this tar, about half remained as pitch, boiling above 300O.Theoils boiling below 300° contained the following substances :1. Unsaturated (ethylenic) hydrocarbons of indeterminate com-position, for the most part richer in carbon than the mono-olefines,(CnH2n).2. Naphthenes (C,H,,) and liquid paraffins, the former greatlypredominating, forming together about 40 per cent. of the oils.3. Phenols, chiefly cresols and xylenols (between 12 and 15 percent:).4. Aromatic compounds (about 7 per cent.), apparently homo-logues of naphthalene, although naphthalene itself did not appearto be present.5. A solid paxaffin in small quantity, of which the melting pointlay between 52'5O and 54O, and of which the molecular weight was373-7 (that is, intermediate between the values required for C,,H,,and c27H56)*These formed between 40 and 45 per cent.of the oils.6. Pyridine bases in traces only.Benzene, anthracene, carbon disulphide, and solid aromatic hydro-carbons were absent, nor was there any evidence of the presenceof toluene or other homologves of benzene in more than minutequantity.The water distilled from the coal contained hydrochloric acidand traces of ammonium chloride.Picht and Bouvier (Zoc. cit.), using a French gas coal, which theydistilled under 15-17 mm. pressure in an iron retort placedvertically and with its mouth upwards, obtained about 4 per cent.of a light tar a t temperatures not exceeding 450O. This tar theyre-distilled, a t atmospheric pressure, between 120° and 300O.Contrary to our results, no phenols were present in their distillates,iior were ammonia or solid paraffins detected.Their preliminaryexperiments also indicated that aromatic compounds, if not absent,existed in traces only. On the other hand, Pictet and Bouvierobtained appreciable quantities of menthol-like compounds and ofbases, chiefly secondary bases.The marked difference between the oils that we have obtainedand those described by Pictet and Bouvier may, perhaps, beattributed to differences in the apparatus employed or to the muehgreater rapidity with which their distillations were effected. (Adistillation was completed in five hours, whereas ours took as manyweeks.)It seems more probable, however, that the differences observedin the oils are due t o differences in the nature of the coals employed,for i t is inconceivable that, assuming the coals t o be similar incharacter, Pictet and Bouvier should find no phenols in their oils142 JONES AND WHEELER: THE COMPOSI'I'ION O F COAL.whilst ours contain as much as 12 per cent.* Further, differencesin character between the Frenca and the British coals are indicatedby the absence from the distillates from the former of solidparaffins which, although small in amount, seem to be essentialproducts of the distillation of all the bituminous coals that we haveexamined.This brings 11s t o the question as to whether free hydrocarbonsnecessarily exist in all coals.The wide distribution of hydro-carbons, and particularly of Dolymerisable hydrocarbons, in plantlife aff orda strong argument for the existence of such polymeridesin coal, despite their known tendency towards rapid oxidation.The fact that paraffins have been found oozing from coal seams,usually in the neighbourhood of a fault (compare Cohen and Finn,J .SOC. Chern. Ind., 1912, 31, 12), is no criterion of what ordinarilyobtains; for such oils may very well have been formed locally fromthe original coal by increased temperature, due to earth-movement,for example, a t some period in the history of the seam.More direct evidence of the existence of hydrocarbons as usualconstituents of the coal substance has been obtained by Pictet andRamseyer (Ber., 1911, 44, 2486), who have isolated hexahydro-fluorene, C13H16, from a portion of a gas coal soluble in benzene.Pictet and Ramseyer regard the existence of hexahydrofluorene intheir coal as lending support to the views of Donath, who considerscoal to consist in part of compounds, originally liquid, that havegradually solidified owing to progressive polymerisation. The factthat hexahydrofluorene was Ihe only hydrocarbon that they couldextract from coal withL benzene, Pictet and Ramseyer attribute tothe possible preferential solvent action of benzene for that sub-stance ; or, alternatively, to the possibility of other hydroaromaticcompounds that may have been present originally having poly-inerised to a greater extent, and thereby escaped solution inbenzene.It should be noticed, however, that Pictet and Ramseyerextracted traces of phenol and bases by benzene simultaneously withthe hexahydrofluorene.We have found that phenols and bases areinvariably products of the low temperature distillation of coals,so that their extraction by a solvent from the particular coal usedby Pictet and Ramseyer suggests the possibility of that coal, atsome time in the history of the seam, having been raised t o atemperature of incipient decomposition, when hexahydrofluorene,phenols, and bases were set free. It is possible, therefore, thathexahydrofluorene, instead of being a survivor from polymerisedcompounds that compose part of the coal substance, may have had* We obtain phenols also in the oils distilled from coal under a pressure of 5 mm.at temperatures as low as 325JONES AND WHEELER: THB COMPOSITION OF COAL.143its origin after the coal substance was formed, and may be anincidental constituent of some rather than an essential componentof all coals.We have obtained evidence of the existence of free, solid paraffinsin several British coals by treating the extract obtained by thesolvent action of pyridine and chloroform (T., 1913, 103, 1704)with pentane. The pentane solution yields crystals of paraffin wax,nleltiiig between 5 5 O and 59O, similar in composition to thoseobtained by the destructive distillation of the coal. This wax formsabout 0.10 per cent. of the total weight of the coal. The argumentsalready advanced against the supposition that hexahydrofluoreneis present in coals generally are, of course, applicable in the presentcase also-free solid paraffins may not be present in all coals.It is necessary now t o discuss the manner in which the varioussubstances that are found in the oils obtained by distillation ofcoal in a vacuum at low temperatures have been formed.It is impossible to explain the formation of liquid (or gaseous)paraffins by assuming a thermal decomposition of free solid paraffins,for these are obviously present in the coal in insufficient quantity.At the same time it is difficult to conceive of their formation, or,for that matter, of the formation of other types of hydrocarbonsfound in the coal distillates, by rapid and complete pyrogenicsynthesis either immediately before or a t the moment of distillation.It seems more reasonable to suppose that the paraffins must bepresent in the coal substance in such a manner that whilst,in a sense, structurally complete, some change in their state, suchas can be produced by moderate heating, must take place beforethey can be set free.The most likely condition of existence of the parailins inaccordance with this supposition, that seems t o us to explain theirappearance in coal distillates, is as alkyl or p a r a h o i d groupsattached chemically to another, non-alkyl, group R.H.Thus wehave the paraffin in what may be conveniently called a “bound”condition, as a component part of a molecule represented by thegeneral formula RH-C,H,,+,, where N may have any value upto 32 or even higher (compare Cohen and Finn, who isolated thehydrocarbon, C32H667 from a mixture of paraffins occurring in acoal seam).The rapid distillation of I‘ free ” paraffins from these ‘ I bound ”molecules when coal is decomposed thermally can now be explainedaccording to the following scheme : ** Compare Engler on the formation of petroleum (Zeitsck.nngew. Chem., 1908,30, 1585)144 JONES AND WHEELER: THE COMPOSITION OF COAL.orRH*C,q?,+, --+ R + CnH,,,, + G,H*?I1 * * (2)It will be seen that with some modification this hypothesis canbe applied to explain the formation of other types of cornpoundsfound in the distillates. Thus, in the case of the naphthenes,whilst we cannot rule o u t the possibility of ring-formation takingplace during the distillation, it is more probable that they existin the coal as “ bound” molecules.F o r the results of recentinvestigations, notably those of Ipatiev (Ber., 1911, 44, 2928), onthe isomerisation or condensation of ethylenic compounds t o formnaphthenes under the combined effects, of heat and pressure, renderit more than probable that under the conditions of the formationof coal saturated ringed carbon compounds have resulted. Theformation of “free” naphthenes from the “bound ” moleculesduring the distillation of the coal can readily be explained accordingto a scheme similar to that given for the paraffins :RH-C,H,,-, + R + CNH2,v . . . . . . . . . . . . . (3)RH*CH,.(:H,.. . CH2*C,H2,-,--+ R+CH3*CH,. . . CH,*C,H:N-l (4)The presence of etlzylenic compounds in the oils may beexplained in part by the breaking down of highly polymerisedethylenic compounds that can reaso,nably be assumed to be presentin the coal substance, the process being comparable t o that whichtakes place when caoutchouc breaks down and yields isoprene; orwe may apply our hypothesis and assume a “bound” ethylenegroup :RH*C,H2,_* -+ R + C,H,, .. . . . ( 5 )Equation 2 also affords a possible explanation of the formationof a portion of the ethylenic compounds.Naphthalene homologues were present in the oils distilled fromcoal in a vacuum up t o 430°, but benzene was absent. There isno reason, according to our hypothesis, why ‘ I bound ” naphthalenegroups and “bound” benzene groups should not both be presentin coal, capable of yielding free naphthalene and free benzene onheating a t low temperatures.The presence of the former type ofcompounds and the absence of the latter in the oils thereforerequires some explanation. I n this connexion the behaviour onheating of their hydrogenated derivatives, concerning which weare able t o record observations made during the course of anotherinvestigation, is suggestive : dihydronaphthalene suffers decom-position a t 400°, yielding chiefly naphthalene and hydrogen ;hexahydrobenzene, on the other hand, remains undecomposed a t450°, the maximum temperature reached in our distillations ofcoal. I f therefore we infer that hydrogenated naphthalene groupJONES AND WHEELER: THE COMPOSITION OF COAL. 145as well as hydrogenated benzene groups are present in coal in the“bound” condition, it can be understood that only the formerwould eliminate hydrogen under the conditions of our experimentsbefore becoming (‘ free,” and that benzene would not appear.Wethus have as a general scheme similar to those already given:In the case of the phenols the assumption of the presence incoal of “bound ” groups, su‘ch as -C6H8<gE3, is rendered doubtfulby the fact that very little of the coal substance is soluble inpotassium hydroxide ; whilst, although (‘ bound ” hydrogenatedgroups might be assumed, as in the case of the naphthalene homo-logues, our knowledge regarding the thermal decomposition ofcompounds of that type is insufficient to enable us to judge whetherhydrogen would be eliminated from them in preference to water.*Russig (Ghem.Zeit., 1902, 26, 190, 344) suggested that phenolsmay arise from the decomposition of polymerised coumarones con-tained in coal, Eraemer and Spilker (Ber., 1900, 33, 2257) havingobserved that pcoumarone, (C8H60)4, begins to decompose a t 300°,’when it yields 17 per cent. of phenol and 51 per cent. of coumarone.As already stated, we find phenols in the oil distilled from coal a t325O, but, if Russig’s theory be accepted, it is difficult t o understandwhy no coumarones, corresponding with the experiments of Kraemerand Spilker, can be detected.EXPERIMENTAL.Distallation in a Vacuum-The general arrangement of thedistillation apparatus was similar to that described in the pre-ceding paper ((( The distillation of coal in a vacuum ’7 ; that is tosay, it consisted of an inverted glass ((retort” connected throughcondensing tubes to a rapidly-acting Sprengel mercury pump.Theretort contained abodt 1’25 kilos. of coal broken into fragmentsand sieved through a 10- and on a 60-mesh sieve, all fine dust beingcarefully winnopred out. The coal was dried for one hour at 105Obefore being put into the retort.For the experiments described in this paper two bituminous* The observation by Ipatiev (Be?.. , 1910, 43, 3383) that 1-methylcyclohexan-2-01,on heating t o 350” eliminates water in preference to hydrogen, has reference onlyto what occurs in the presence of alumina.VOL. cv. 146 JONES AND WHEELER: THE COMPOSITION OF COAL.coals (one from Scotland and one from Durham) were employed,the proximate and ultimate analyses of which were :Proximate Analyses.' I Volatilematter." Fixed carton. Ash.Scotch coal ......26'36 70-36 3.28 per ceut onDurham ,, . . . . . . 30 '81 65.09 4-10) dry coalU 1 t imn t e A na I y ses.Carbon. Hydrogen. Oxygen. Nitrogen. Sulphur.Scotch coal ...... 86.92 4.98 5-56 1.75 OT9 per wnt. on ash-Durham ,, ...... 86-88 5'41 4'71 1-75 1-25) free dry coalI n early experiments fractional distillations of the coal a tdifferent temperatures were conducted in the manner described inthe preceding paper. It was found, however, that there was noappreciable difference in the character of the liquids distilled a tthe different temperatures, ,so that in the later experiments thecoal wits raised slowly direct to 430° and maintained a t thattemperature.The bulk of the distillate collected in the first receiver, whichwas not surrounded by any cooling-mixture.It consisted of athin, brown, pleasant-smelling tar, which was covered with a layerof paraffins, The specific gravity of the tar was 0*999:.;, which ismuch iower than that of ordinary coal tars.The second and third condensers, which were cooled by a solutionof solid carbon dioxide in ether, contained a reddish-brown oil witha lower aqueous layer containing hydrochloric acid and ammoniumchloride."A certain quantity of oil passed through the Sprengel pumpwith the gases evolved during the distillation and condensed underatmospheric pressure ilz the connexions leading t o the apparatusfor collecting the gases.This oil was of a pale straw colour, boilingbetween 116O and 154O/760 mm., and had a specific gravity of0.781g. On combustion analysis, 0.1430 gave 0.4547 CO, and0.1712 H20. C=86.72; H=13.30 per cent. This oil was not furtherexamined separately, but was added to the main bulk.E x a m i n a t i o n of t h e Volatile Oils.-Oils of very low boiling pointwere removed from the gases collected by passing the latter slowlythrough a condenser cooled by solid carbon dioxide and ether. The* A fraction obtained a t 350" fumed strongly in the air and lied n specific gravityof 1.135. The supernatant oil contained traces of a chloro-derivative, presumablyformed hy the addition of the elements of hydrogen chloride to some unsaturatedcompoundJONES AND WHEELER: THE COMPOSITION OF COAL. 147liquid so obtained was warmed to 35O to free it from dissolvedgases,* and was found to boil between 35O and 125O.It had aspecific gravity 0*699:,5, and 0.1732 on combustion gave 0.5394 CO,and 0-2272 H,O.Itwas clear and limpid, and remained so on long keeping. It rapidlydecolorised potassium permanganate solution, and a solution ofbromine in chloroform.In order to remove and estimate the quantity of olefines present,a portion of the crude oil was first washed with concentratedsulphuric acid in a small, graduated separating-burette, rise intemperature being guarded against. A considerable quantity of“ acid tar ” was formed, and the volume of the oil was reduced from5.1 C.C.to 3.0 c.c., whilst its specific gravity rose slightly (from0.69 to 0.71).The ‘‘ acid t a r ” was heated in steam a t 180°, and the distillateexamined for benzene. A negative result was obtained. The oilitself, with the ‘( acid tar ” removed, was then examined for benzenein the following manner. The oil was washed with fuming nitricacid (D 1-50>, and the acid washings were diluted with water. Thereddish-brown deposit thus formed was washed and dissolved inalcohol and treated with (1) zinc and sulphuric acid, and (2)potassium hydroxide solution. The mixture was then distilled insteam, and the first runnings tested for aniline with a fresh solutionof bleaching powder. The negative result obtained demonstratedthe absence of benzene in the oil.After having been washed with nitric acid, as stated above, theoil was treated with weak fuming sulphuric acid, whereby the lasttraces of olefines were removed.+ It was then freed from acid bywashing with water, with a solution of sodium carbonate, and,finally, with water again, and distilled. The distillate was collectedin two fractions, the first boiling between 48O and looo, and thesecond between looo and 135O.On combustionanalysis the following figures were obtained : 0.1280 gave 0.3964CO, and 0.1797 H,O.Comparison of these figures with the known values of carbon andhydrogen f o r naphthenes and paraffins boiling over about the rangeof temperature of the oil shows conclusively that the oil was amixture of these two classes of compounds:* These gases contained : olefiiies, 23 5 per cent., and paraffins, 75.4 per cent.byvolume, the ratio n/V for tho paraffins being 2.5.T The acid used was of the strength recomniended by Zeliuski for similar work(Ber., 1912, 45, 3678), and consisted of a mixture of two parts of sulphuric acid(D 1’84) and one part of a 7 per cent. fumiag sulphuric acid.C = 84-94 ; H = 14.57 per cent. (C + H = 99.51).This liquid had an extremely unpleasant, garlic-like odour.The first fraction had a specific gravity 0*691:,5.C = 84.46 ; H = 15-60 (C + H = 100-06).L 148 JONES AND WHEELER: THE COMPOSITION OF COAL.C,Hlo n-pentane (b. p. 36') requires C=83.3 ; H= 16.7 per cent.C,H,, n-hexane (b. p. 6 9 O ) ,, C=S3*7; IS= 16.3 ,,C,H,, n heptane (b.p, 98') ,, C=S4.0 ; H = 16.0 ,,C,H,, n-ocbine (b. p. l Z S o ) ,, c1= S4.2 ; €1 = 15.8 ,,C,H2, naphthenes require C = 85.7 ; H = 14.3 per cent.The second fraction, boiling between looo and 135O, was analysed.Here again it is clear that a mixture of naphtAhenes and paraffins0.1353 gave 0.4234 CO, and 0.1846 H,O.was present:C,H,, n-nonaneC,H,, n-octane (b. p. 1 2 6 O ) ,, C = S 4 - 3 ; H=15.8 ,,C,H,, 9%-heptane (b. p. 98O) ,, C = 81 0 ; 11 = 16.0 ,,C = 85-34 ; H = 15-16.(h. p. 150') requires C = S 4 . 4 ; I { = 15% per cent.C,H,, naphthenes require C = 85.7 ; H = 14.3 per cent.We have not as yet attempted any direct examination of theolefines contained in the crude oil, nor of those found in thehigher boiling oils described later.I n the present instance thehydrogen content of the olefines, as calculated indirectly from theanalyses of the oil before and after washing with sulphuric acid,was about 13.3 per cent.; that is, cansiderably lower than that ofthe mono-olefines, C,H2, (I3 = 14.3 per cent.). Whilst some open-chain (mono-olefines) were very probably present, it would seemthat there were also unsaturated compounds cyclic in structure.Oils of Higher Boiling Point.-The oils now examined wereobtained from the two cooled condensers and from the pump con-nexions. To these was added that portion of the tar collected inthe first receiver that distilled below 200°/30 mm.These oils were washed with dilute sodium hydroxide solutionto remove phenols, and with dilute sulphuric acid to remove bases.The basic compounds recovered were too small in quantity to beexamined.After removal of phenolic and basic compounds, the oils werewashed with a solution of sodium carbonate and with water, and,after having been dried over anhydrous magnesium sulphate, weredistilled.The composition and specific gravity of successivefractions of the neutral oils are given in the table below :Fraction. I. 11. 111. 1v. -The phenols are described briefly later.Boiling point ................ 160--2UO" 200-2.50" 250-275" 275 --300"Cnrlwl ......................... 86-28 87.88 88.13 88 '24Hytlrogcn .................. 13.1 1 11 %5 11.09 10-36C - F H ........................ 99.39 99 53 99.22 58 60Sl~eciBc gravity, 15/15 ..,......0.804 0.556 0.890 0'928These neutral oils thus consisted almost entirely of hydrocarbons.They were colonrless, and had a disagreeable, penetrating odour.They rapidly decolorised potassium permanganate solution and JONES AND WHEELER: THE COMPOSITION OF COAL. 149solution of bromine in clilorof orin, and they also readily addedon the elements of hydrogen chloride. On boiling with anhydrouszinc chloride they polymerised but slowly, nor did they absorboxygen with any rapidity.The oils were now washed with concentrated sulphuric acid(U 1-84), whereby unsaturated etliyleiiic compounds were removed ;and afterwards, for the removal of aromatic compounds, eitherwith weak fuming sulphuric acid or with nitration mixture.It was found that washing with concentrated sulphuric acidgenerally reduced the volume of t h t oils by about one-half, andthat there was a concomitant lowering of their specific gravity.The oils obtained after further exhaustive washing with weakfuming sulphuric acid and with nitration mixture were freed fromacid, dried over sodium, and distilled from sodium in a vacuum,care being taken to avoid their decomposition.The refined oilswere clear liquids with a pleasant odour resembling that of refinedpetroleum. On analysis it was found that the carbon percentageswere too high for the paraffins of corresponding ranges of boiling.They approximated from a slightly lower figure up to 85-7, whichis the value for the percentage of carbon in the naphthenes, C,H2,.The same results were obtained with 211 the oils after exhaustivewashing with weak fuming sulphuric acid and nitration mixture.It is noticeablethat the fractions of lower boiling point appear t o consist ofmixtures of paraffins and naphthefies, whilst the fractions of higherboiling point must either consist of naphthenes only, or, what isless likely, of mixtures of paraffins with hydrocarbons richer incarbon than the polymethylenes :Fraction. I.11. 111. I v. v.Boiling point .........Specihc gravityl5/15 - 0 7841 0.7844 - -Cnrbon .................. 8 5 - 4 i 85-42 85.26 85.56 85-82Hydrogen ............ 14.46 14.73 14'56 14'65 14-36C + H ............... 99-93 100.15 99-82 100-21 100.18The analyses are set forth in the table below.150-190" 190-260" 200-250" 225-260" 160-260°/30mm.CloH22 (b.p. 173O) has D 0.747, and requires C=84.5; H=15*5.C1,H,, (b. p. 330O) ,, D 0.777 ,, C = 85.09 ; €I = 14.91.Naphthenes, require C = 85.7 ; H = 14.3 per cent.It will thus be seen that whilst the carbon-content of any mixtureof paraffins that may conceivably be present would fall below 85.0per cent., that of the refined oils is invariably higher and approxi-mates t o 85.7, the value for the naphthenes.Phenols.-The washings from the oils with sodium hydroxide werefirst treaked with ether t o remove dissolved oil, and afterwardsacidified with dilute sulphuric acid and extracted with ether. Theethereal solution was dried with anhydrous magnesium sulphate150 JONES AND WHEELER: THE COMPOSITION OF COAL.and filtered, and the ether evaporated.The phenols remainingwere distilled in a vacuum. A fraction collected between looo and145O/30 mm. had a specific gravity of 1.0372, and on analysis gavethe following results, which show it t o consist essentially of amixture of cresols and xylenols:0.2464 gave 0.7078 CO, and 0.1758 H,O. C=78*34; H=7*93.Cresols (C,H,O) require C = 77-77 ; H =I 7-40 per cent.We were unable to determine whether phefiol itself was present.Aromatic Compo liiids.-If the neutral oils boiling between 200°and .300° are heated and their vapours aspirated through ailaqueous solution of picric acid, crystals of picrates are deposited,those from the fractions of lower boiling point being yellow, andthose from the fractions of higher boiling point dark red.A quantity of apparently pure picrate, but insufficient foridentification, was obtained from a fraction of the oils boilingbetween 250° and 300O.This picrate was dark red, and meltedsharply a t 1 1 8 O .On treating that part of the neutral oils boiling between 170°and 300° with picric acid and warming, the liquid became darkred, but no precipitate was obtained on cooling. On the additionof pentane, picric acid mixed with a picrate was precipitated. Thisprecipitate war decomposed in a current of steam, the distillatecollected being a viscid oil of specific gravity 1%019::, and having anodour resembling that of crude naphthalene. 0.1905 gave 0.6420CO, and 0.1326 H,O.Dimethylnaphthalene (CI2Hl2) requires C = 92.31 and H = 7.69per cent.The values obtained from the combustion analyses, taken inconjunction with the physical characteristics of the oil and itspicrates, which are stable in the presence of water, point to theoils being homologues of naphthalene.Naphthalene itself couldnot be detected.Solid Parafii?s.-Of the tax contained in the first condenser, thatportion boiling abave 200°/30 mm. was distilled in a vacuum. Thedistillate obtained between 200° and 260°/ 30 mm. was analysed :0.2032 gave 0.6370 CO, and 0.1741 H,O. C=85*49; H=9.52(C + H = 95*01), showing that compounds other than hydrocarbonswere present.The portion of the oil that boiled a t 200-240° in a vacuumwas a pale yellow liquid, whilst that boiling a t 260° cooled to ared-coloured paste. The fraction boiling between 220° and 240°in a vacuum partly solidified on cooling, needle-shaped crystalsbeing deposited. Those crystals were recovered by removing anyXylenols (C8Hl,0) ,, C=78*67; H=8.20 ,,C = 91-91 ; H = 7.73 (C +- H = 99.64)INTERACTION OF GLYCEROL AND OXALIC ACID. 151resinous matter by charring with concent rated sulphuric acid andextracting with light petroleum. On t ctrystallising twice fromacetone, pure crystals were obtained, which melted between 52-5Oand 54O. On analysis: 0.1554 gave 0-486.5 CO, and 0.2097 H,O.C = 85-38 ; H = 14.99. A molecular-we~gl~t determination gave avalue 373.7, that is to say, intermediak between the values requiredfor C,,H, and C2J€,,.Searchwas made in the fractions of higher boiliug point for anthraceneby oxidation with chromic acid, but no trace of anthraquinone wasobtained. There is no reason t o believe that aiithracene or othersolid aromatic compounds were present.Pitch-The residue remaining from the coal distillate when thelatter was distilled in a vacuum up to 260° consisted of a soft,stringy, shining pitch of specific gravity 1.128;;. This pitch wasentirely soluble in chloroform, aad was free from carbon. 0.2101gave 0.6782 CO, and 0.1487 H,O. C=88-04; H=T.87 (C+H=95.91). This pitch is being further examined.Committee of the Home Office for permission to publish thispreliminary account of their wcrk,No other solid compound was found in the distillate.The thanks of the authors are due t o the Explosions in 1 11. 1nesESKMEALS.CUMBERLARD

ISSN:0368-1645    

DOI:10.1039/CT9140500140

出版商:RSC    

年代:1914

数据来源: RSC