摘要:

1404 KING THE PRODUCTION OF CXXXI1.-The Production of Methy2 Ethyl Ketone from n-Butyl Alcohol. By ALBF~RT THEODORE KING. IN this conversion the usual series of steps has been employed of dehydration re-hydration of the resulting alkylene to the secondary alcohol and finally dehydrogenation of the latter to give the corresponding ketone : R*CH,*CH,*OH + R*CH,:CH -t R*CH(OH)*CH -+ R*CO*C€13. No details appear to have been published hitherto regarding the hydration of butylene to tlie secondary alcohol and although the first and last of the above stages have in this particular case been elsewhere described the comparative results now obtained seem worthy of being placed on record also. Dehydration of n-Bzctyl AZcolzoL-Each of the three possible butylenes, CH,- CH,*CH:CH CH,-CH:CH*CH (CH3)?WH2, a-.13-. Y-. has been identified by previous observers in the product of dehydr-ation the composition of which would appear to depend both on the nature of the dehydrator and on the temperature employed. Thus Ipatiev ( J . Russ. Phys. Chem. SOC. 1903 35 577) wit METHYL ETHYL B ~ O N E FBOM N-BUTYL ALCOHOL. 1406 alumina as catalyst a t 500° obtained a gas containing 25-30 per cent. of a-butylene the rest being y-butylene; the latter was attributed to the presence of isobutyl.alcoho1 in the material employed. Senderens (Ann. Chim. Phys. 1912 [viii] 25 449), using aluminium sulphate a t 300° obtained a-butylene with 27 per cent. of y-butylene. Le Be1 and Green obtained on dehydration with zinc chloride a product free from y-butylene and containing 80 per cent.of P-butylene and 10 per cent. of a-butylene (Bull. Soc. chinz. 1881 [ii] 35 438). I n the present investigation in which phosphoric acid on pumice was used only slight differences were observed in the composition of the product a t temperatures ranging from 280° to 400O. No y-butylene was detected and even a t 280" the amount of a-butylene present so far as was indicated by fractionation of the bromide could only be slight. This method of dehydration there-fore yielding reasonably pure B-butylene gives a much more homogeneous product than those previously described. Hydration of ButyZenes.-The hydration of the three butylenes with sulphuric acid should theoretically proceed as formulated below : CH,* CH,-CH( OH)* CH \ CH,*CH,.CH:CH, CH,*CH:CH*CH f (CH,),C:CH -+ (CH,),C*OH This conversion in the case of y-butylene has been described by Butlerov (AmaZen 1875 180 245) who also records the very slow hydration of /3-butylene but without details of the isolation of sec.-butyl alcohol.Nor is the formation of the latter from a-butylene recorded; and this point is under examination the present investigation dealing only with the behaviour of 8-butylene. The rapid absorption of @-butylene (as also of u- and y-butylene) by concentrated sulphuric acid is well known but by this action polymerisation and not hydration results. With diluted acid, the very slow action on keeping has been confirmed but liquefied 8-butylene under its own pressure agitated in contact with the acid has been found to undergo absorption with ease.Polymerisa-tion which is marked a t the higher concentrations is very slight with 78 per cent. acid and below this strength the reaction proceeds normally. In one case an absorption was observed of nearly 20 per cent. in excess of the butylene theoretically required to convert the acid t o butylsulphuric acid suggesting that the latter is capable of 3 a 1406 KING THE PRODUGTIOTT OF catalysing the direct hydration of 8-butylene. It is hoped to investigate this point further. The diluted solution on distillation readily gives the secondary alcohol in good yield. Dehydrogenation of sec.-Butyl A 1cohol.-Reduced copper is recorded by Sabatier and Sender ens as being particularly efficient in catalysing the dehydrogenation of secondary alcohols these showing a conversion without complications but incomplete owing to the reverse action also taking place in the presence of copper.They observed the formation from sec.-butyl alcohol of methyl ethyl ketone and pure hydrogen without any accessory reaction, within the temperature range of 160-300° (Ann. Chim. Yhys., 1905 [viii] 4 433 465). In the present work the reverse action above referred to was perceptible but only slight. EXPERIMENTAL. Preparation of P-Butylene. The +butyl alcohol distilled a t 116-118O. It was gently boiled in a silica distilling flask attached t o a 2.2 cm. copper tube 150 cm. in length capable of giving by electrical heating temperatures, registered a t the middle part from 280° to 400O. This was packed with fragments of ignited pumice impregnated with glacial phos-phoric acid.(This catalyst can be used indefinitely its activity being renewed occasionally by burning a piece of phosphorus a t the mouth of the tube with a current of air passing through.) The unchanged alcohol and water formed were collected in a receiver with water-cooled reflux and with a syphon tube for the disuharge of the condensate from time to time. The gaseous pro-duct after scrubbing with 60 per cent. sulphuric acid to retain any y-butylene was absorbed in cooled bromine until the latter was nearly colourless. The product was then shaken with dilute alkali dried with calcium chloride and systematically fractionated. The following are typical results: (1). (2)- (3). Temperature ..................300-320". 280-300". 400". Dried product .................. 75 grams. 114 grams. 120 grams. Find fractions :-below 155" 153-157'. 3.5 9 9 2 Y Y 9.0 Y9 8 Y 9 155-157' -157-159 60 99 92 99 98 9Y 164-161 3 9 9 3 9 9 6 99 residue 3 9s 3.5 I# 4 9 s ( 7 grams METHYL ETI~YL KETONE FROM N-BUTYL ALCOHOL. 1M7 The boiling points of the three dibromides are a- 1 6 6 O ; & cis-form 158O; tram- 161O; y- 1 4 9 ~ 6 ~ . Thus a-butylene is not present even at the lowest temperature employed in notable quantity. The low fraction possibly indicating the presence of y-butylene was not appreciably increased in (2) in which waahing with 60 per cent. acid was omitted and these lower fractions were not in sufficient quantity to detect by further fractionation the presence of y-butylene dibromide.Moreover no tert .-butyl alcohol was obtained from the 60 per cent. acid used to wash more than 100 grams of gas. On dilution and distillation it yielded only 3 grams of product which proved t o be mainly n-butyl alcohol carried over. Much of the butylene formed dissolves in the butyl alcohol which escapes dehydration and condenses in the receiver. From this solution more than 150 times its volume of butylene is expelled on raising to boiling point. The un-changed alcohol layer dried and fractionated yielded finally, 1-2 per cent. distilling below 1 1 6 O the rest passing over a t 116-118O and for continuous working the condensate was shaken with salt and the upper layer separated and used again thus conserving the dissolved butylene .No side-reaction was observed in the dehydration. Action of Sulphuric Acid on /3-Butylene. On bubbling the gas through concentrated sulphuric acid rapid absorption took place the liquid becoming warm and darkening in colour. A pale yellow upper layer formed and when this had increased to about 10 C.C. in volume it wm separated washed and dried with calcium chloride. It had a slight odour of hydrocarbon, and on distilling boiled without any constancy from 140° to 300O. The sulphuric acid layer gave on pouring into excess of water a turbid liquid from which a small quantity of oil separated which gradually darkened and became very viscous. These producta, presumably formed by polymerisation of the 6-butylene were not further investigated.No secondary alcohol was detected in the aquous portion. With diluted acid even up to 78 per cent. no appreciable absorption took place when the gas was merely bubbled through. For absorption under pressure the following procedure was used. The gas was liquefied by passing through a worm cooled in a mixture of ice and salt the outlet tube dipping under the acid contained in a stoubwalled bottle also cooled in ice and salt. This gave good condensation bubbles of gas escaping only a t rar 1408 KINU THE PRODUOTION OF intervals. The bottle was then closed by a rubber stopper wired down and after weighing to ascertain approximately the amount of butylene condensed shaken in a mechanical shaker until the butylene layer had disappeared. I n each case 50 C.C.of pure acid were used with varying dilution and the time occupied for absorp-tion was roughly noted with the following results: Concentration. Per cent. 84-0 78.0 7 6.0 76-3 72.5 70.0 64.8 50.0 100 Butylene. Grams. 17 21 23 22 22 19 24 10 22 Time taken. 5 minutes -20 9 9 40 y y 1 hour 1.6 hours 5 9 ) 8 Little ' k e c t after 15 hours. With pure acid the absorption was complete in a few seconds. On pouring into ice an oil separated which after drying with calcium chloride weighed 15 grams. It distilled from 140° to above 300° without boiling constantly a t any point like the pro-duct previously described. No secondary alcohol was present in the aqueous poition. With 84 per cent. acid the alcohol was the main product but considerable polymerisation occurred.Moreover the acid crystal-lised in the freezing mixture causing inconvenience through block-ing of the delivery tube. The freezing-point curve shows the range of concentration having sufficiently low freezing point and also giving normal reaction in reasonable time to be from 74.5 (f. p. - 20°) to 78 per cent. (f. p. -ZOO). The concentration ultimately adopted was 75 per cent. With 78 per cent. acid a trace of oil with a terpene-like odour was observable on dilution this becoming imperceptible with the lower concentrations. The rise of temperature was very marked with the higher con-centrations. The pressures generated by the liquid butylene were approximately determined by a pressure gauge as follows : 1 2 O 0.6 atm.20 0.95 ,, 30 1.4 19 40 1.9 1 , With 75 per cent. acid the temperature did not reach 40° and the operation is thus without risk. To ascertain the extent of absorption 76 per cent. acid contain-ing 92 grams of pure acid was shaken with 63 grams of- butylene (theoretical quantity= 51.5) for fifteen hours. The excess of gas was allowed to escape and any in physical solution removed b METHYL ETHYL KETONE FROM N-BUTYL ALCOHOL. 1409 exhaustion when 61 grams were found to have been chemically absorbed. About 90 per cent. of the theoretical quantity was, however usually employed. Hydrolysis of Butylsulphwric Acid. Comparative experiments were made using three portions of 50 grams from the same batch of butylsulphuric acid. These were respectively neutralised with sodium carbonate and treated with quantities of 50 and 25 grams of water.The liquids were dis-tilled and the distillates caught in graduated tubes and thoroughly shaken with salt solution and a slight excess of salt. The volumes of upper layer were 23 c.c. 23 c.c. and 22.5 C.C. respectively. With neutralisation as employed by Butlerov (Zoc. cit.) the alcohol distilled over very slowly with a large quantity of water. Dis-tillation with the lesser quantity of water gave a distillate with only a small aqueous layer the bulk being retained by the acid, but with a slightly lower yield although no ether was detected in the product. Dilution with an equal weight of water was therefore adopted. With this procedure 51 grams of butylene yielded a distillate which after salting out and drying with potassium carbonate, weighed 60 grams that is 89 per cent.of the theoretical on the crude material. From 150 grams of dried undistilled product, after careful fractionation were obtained as final fractions : below 97.5' 3 grams 131 Y9 residue 5 9 9 The fraction 97.5-99.5O was employed for conversion to ketone. ,9;:E;;F 8 Y Y Dehydrogenation of sec.-Butyt A Icohol. The procedure followed was substantially that of Sabatier and Senderens (loc. cit.). A copper tube 172 cm. long and 1.2 cm. in diameter was packed with copper oxide from wire kept in place with plugs of rolled copper gauze and enclosed in a 2.5 cm. copper tube 135 cm. long wired for electrical heating. After reduction of the wire with ethyl alcohol vapour and expulsion of the latter, sec.-butyl alcohol was distilled through from a silica flask a t such a rate that the distillate passed through a t the rate of about one drop a second.This was caught in a receiver cooled in ice-water. The hydrogen was evolved just too fast to allow the bubbles through a wash-bottle to be counted. The temperature remaine 1410 ARMSTRONG AND HILDITCH CONVERSION OF THB 8IMPLE fairly constant throughout the fluctuation on either aide of 290° being never more than 5O. In the first preparation from 100 grams of alcohol 104 of distillate were obtained. This contained water formed from some unreduced copper oxide and on fractionating 94 grams distilled a t 73-75O the mixture separating a small lower layer of water. After drying with potassium carbonate the bulk distilled a t Two hundred and fifty grams of alcohol gave an almost 79-81'. theoretical yield of following fractions : dried undistilled product which gave the 76-79' 5 grams 79-81 199 9 9 81-82 9 9 9 82-86 6 9 9 residue 1.2 Y, Thus the conversion is upwards of 90 per cent. 'The fraction boiling a t 79-81O decolorised permanganate but after stirring with about half a gram of powdered potassium per-rnanganate for a short time the colour persisted. On distilling off and drying thoroughly with potassium carbonate (the boiling point is very easily affected by traces of water) the ketone distilled almost completely within the range 80-80.6°. The yield on the small scale from the crude butylene is about 70 per cent. of the theoretical and with continuous working and recoveries this figure a t least should be reached in the complete synthesis from n-butyl alcohol. IMPERIAL COLLEGE OF SCIENCE AND TECHNOLOQS, SOUTH KENSINGTON. [Received h'owrnB( r 18th 1 91 9.

ISSN:0368-1645    

DOI:10.1039/CT9191501404

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

1410 ARMSTRONG AND HILDITCH CONVERSION OF THB 8IMPLE CXXXIT1.-Conversion of the Simple Sugars into their Enolic and Ethylene Oxide Forms. By EDIWARD FRANKLAND AWSTRONG and THOMAS PERCY HILDITCH. No group of compounds is more remarkable than that of the hexoses on account of their extreme mutability. Glucose for example may be obtained in an a- and a /3-crystalline form and if either of these is dissolved in highly purified water the solution i s all but stable. Yet if a trace of alkali is added an equilibrate BUGAM INTO THEE BNOLIC AND ETHYLENE OXIDE] FORMB. 1411 mixture of the two isodynamic forms is practioally instantaneously produced. The change has been specially studied by Lowry (T., 1903 83 1314; 1904 85 1551) and its character has been dis-cussed also by one of the authors (T.1903 83 1305). The more gradual change also under the influence of alkali, from one hexose into another within sections including as many as four members of the group (for example glucose +- - mannose - fructose glutose) was brought to light through the pains-taking labours of the late Lobry de Bruyn (Rec. trav. china. 1895, 14 156 204). In this case the transition has been assumed to involve the formation of an enolic form as an intermediate term. In the case of the hexoses the aldehydic form (aldehydrol) is commonly supposed to have but an ephemeral existence and it is held that OG and @-glucose are butylene oxide or pentaphane deriv-atives corresponding with the two methyl glucosides. The latter, i t is well known are simultaneously produced by the action of a strong acid on glucose dissolved in methyl alcohol; a residue long unexplained has recently been shown to contain a third isomeric methyl glucoside regarded by Fischer and by Irvine as the derivatives of an ethylene oxide form of the hexose.Irvine and his school (T. 1915 107 524; 1916 109 1305 etc.) have shown that the new methyl glucoside is characterised by its capacity to condense with acetone to reduce potassium perman-ganate solutions and to undergo auto-condensation and that the activity of the parent glucose from which it is derived far exceeds that of a- or &glucose. The observations we have to place on record relate to the changes effected in the simple sugars by acids and by alkalis as measured both by means of the polarimeter and by means of increased liability to oxidation.A solution of either a- or &glucose in water (both well purified) is practically unaffected .by permanganate. I n acid solution, reduction of the permanganate sets in a t once and at a definite rate under definite conditions ; thus under the standard conditions detailed in the experimental part 10 C.C. of 1 per cent. of a- or B-glucose in Rl 10-hydrochloric acid solution decolorise 2 C.C. of 3 / 100-permanganate solution a t 2 5 O in twenty-eight to thirty minutes. That the change is instantaneous is proved by the fact that the reducing power acquired is independent of the time during which the acid has aoted solutions containing acid which have been kept various times all having the ~ a m e reducing power.The strength of the acid however is a factor in the change the effect being less the weaker the acid and likewise the less concentrated the acid. * 3 Q 1412 ARMSTRONG AND HLLDITaH CONVERSION OF THE SIMPLE We coxwider that the active agent is the ethylene oxide modifi-cation of glucose, CH,(OH)*CH(OH) *CH(OH)*CH(OH)*CH*CH*OK* \/ 0 The amount of the ethylene oxide form present is regulated by an equilibrium depending on the strength of the acid but that it is small is shown by the fact that the optical rotatory power of glucose in an acid is the same as in an aqueous solution. The ethylene oxide form is reproduced as oxidation by the perman-ganate proceeds as shown by the fact that fresh additions of permanganate solution are decolorised.Mannose and fructose are affected by acids in a similar way but the altered mannose solution acts far more rapidly than that of glucose; fructose is only slightly less active than mannose. For example under precisely comparable conditions whereas the reduc-tion of permanganate by glucose occurs in twenty-eight t o thirty minutes that by mannose takes only from twelve to thirteen and that by fructose sixteen to seventeen minutes. CH,*OHt' I CH2 I\O ,C*OH CH*OH H O d 0 ] p o o/j H d \CH \ I H O ~ H H O ~ H H O ~ H H O ~ H or CH H OH H&OH H&OH ~ 1 3 - O H H &OH H C ~ O O H H ~ O H H ~ O H H ~ O H H&OH ~H,*OH ~H,*OH &H,.OH ~ T ~ . O H ~H,*OH Glucose. Mannose. L Y / Fructose. In view of the close relation of the ethylene oxide forms of these sugars it seems not improbable that one of the isodynamic forms is the more oxidisable and that this is the form present in mannose.The reduction of permanganate (as well as of methylene-blue and of indigo-blue) is also promoted by the addition of alkali. In * A t first sight the alterations involved in the conversion of butylene oxide into ethylene oxide or enolic forms of glucose appear somewhat far reaching when viewed only in the light of the conventional structural formulae. If, however structural models are prepared of the sugars on the lines of the Pope-Barlow hypothesis of close packing a more rational interpretation of the changes is realised. f This form of fructose is present in sucrose according to Haworth and Law (T. 1916 109 1314) BUUARS INTO THEIR ENOLICI AND ETHYLENE OXIDE FORMS.1413 this case however the change of the hexose is more gradual as, within limih the solution is the more active the longer the alkali has acted. The interactions in the three cases take place a t corre-sponding rates showing that in each case the same change is being studied Under the experimental conditions observed the reduc-tion phenomena correspond only with the changes in structure which take place in the course of the first few hours and it is unlikely that any far-reaching disturbance has occurred in the carbon chain beyond the atoms 1 and 2. As shown by the polarimeter the equilibrium between the a-and B-butylene oxide forms of the sugar is established instant; aneously in alkaline solution and subsequently the optical activity falls slowly but it is still of considerable magnitude a t the end of six hours.After this it continues to fall some fifteen to twenty days being required before the solution loses its activity. To judge from the slowness with which alkali acts as compared with acid taking into account the instantaneous equilibrium of the u-and &forms in the presence of alkali it is clear that the latter are not concerned in the change. It therefore seems probable so far as the effect produced by acids is concerned especially in view of the distinctly basic character of ethylene oxide that the ethylenic oxide form of the hexose not an enol is the active agent. Assuming the enol to be concerned acids equally with alkalis should convert one hexose into another in the Lobry de Bruyn change but this is known not to be the case.It is noteworthy however that ethylene oxide itself has no reducing power on either methylene-blue or indigo-blue in alkaline solution although it readily affect<s permanganate. It is by no means clear in fact that the action of alkali is comparable with that of acid and it may well be that reduction is effected by the enol. Whereas possibly in acid solution a salt of the basic ethylene oxide hexose is formed in alkaline solution the scission of all ring systems and the production of a metallic salt of the open-chain enol appears more probable. Whilst glucose decolorised the standard amount of permanganate initially in eleven minutes (in the presence of one equivalent of sodium hydroxide) fructose takes three and mannose twenty-five minutes; the figures after the solutions have remained for five hours are respectively glucose 3 fructose 1.25 and mannose 9 minutes.As the formulae show all three substances can give the same enolic form. On the supposition that “enol” rather than ‘‘ ethylene oxide ” is initially formed in the presence of alkali the configuration represented by fructose is most and that represented 3 a* 1414 BRMSTRONQ AND RUCIDITOH CIOHVIORSION OF THE EIIMPLIB by mannose least prone to undergo enolisation. contrast to the behaviour of the same three sugars towards acid. This is in marked CHO CHO CH*OH CH,*OH &OH 60 I H&OH H O ~ H H O ~ H H O ~ H H O ~ H 4- HO-OH -+ a6-OH H ~ O H H ~ O H H&OH Hh*OH H&OH H&OH ~ 6 .0 ~ I dH9*OH dH,*OH CH,mOH dH,*OH Gluooee Mannose. Common enolic Fructose. form. CH,*OH I &OH b 0 H H ~ O H Hb*OH bH,*OH Fructose alternative enol. The change in presence of alkali is qualitatively proportionate to the strength of the alkali. It is of special interest in this con-nexion that pyridine has a similar effect to the other alkalis. In this case as pyridine is such a weak alkali the sugars were dis-solved in the base itself. Decolorisation of glucose took place initially in about fifty to sixty minutes increasing to thirty minutes in about five hours whereas with fructose the times were thirty minutes initially and eight minutes after six hours. This observation is quite in harmony with the important part which pyridine and quinoline have played in sugar chemistry as the media in which epimeric changes are effected causing the re-arrangement of the groups attached to the asymmetric carbon atom at the end of the chain.Both in the interconversion of epimeric hexonio acids (E. Fischer Ber. 1890 23 2625) and of epimeric glucosides (E. Fischer and von Mechel Ber. 1916 49 2813; 1917, 60 71 l) formation of intermediate modifications must be involved. The alterations in structure which we have followed by the changee in reducing power are clearly in no way related to those known as mutarotation. Whereas the former take place instant-aneously in the presence of acid and more slowly in the presence of alkali mutarotation is brought about immediately in the presence of alkali and more slowly in the presence of acid.EXPERIMENTAL. Reducing tests were made by withdrawing 10 C.C. of the sugar solution (generally 1 per cent. or 1 / 18 gram-molecule of hexose per Iitre except when polarimetric comparisons were also made in which case 5 per cent. solutions were used) into a stoppered test-tube and adding 2 C.C. of the standard permanganate or dye solu-tion ; N / 100-potassium permanganate was invariably used whils SUQARS INTO THE33t PNOLIU AND ETRYLENE OXIDE FOBBSS. 1414 the dye solutions consisted respectively of a 0-025 per cent. solu-tion of methylene-blue and a solution of neutral indigo sulphonates which contained 0.045 per cent. of indigotin. In those cases in which it wits desired simultaneously to neutralise the acid or alkali present special solutions of N / 100-permanganate were employed containing respectively the amount of sodium hydroxide or of sulphuric acid per 2 C.C.necessary to neutralise the acid or alkali present in the 10 C.C. of sugar solution exactly. The behaviour of permanganate with the sugar solutions varies considerably according to the conditions studied ; thus acid fructose or mannose solutions pass simply from pink to clear white and perfectly definite end-points are obtainable in these cases. Ip other cases generally those of slowly reducing acid media or of rapidly reducing neutral or alkaline solutions the pink tint gives place with varying rapidity to a very pale yellow and ultimately t o the colourless condition.A definite colour standard just short of colourless was adopted here and sharp end-points could be obtained without difficulty. With slowly reducing neutral or weakly alkaline solutions however a precipitate of manganese dioxide of variable degree of fineness is apt to appear and it is difficult to determine the precise point a t which actual precipita-tion sets in; cases of this kind are denoted in the tables which follow by the addition of “ indefinite ” or “with pptn.” It is obvious that in the latter case the amount of reduction will not be so great as when the formation of the colourless manganous salt solution has occurred. I n point of fact whilst the 10 C.C. of sugar solution employed has contained 0.1 gram (1 per cent. solu-tion) or 0-5 gram (5 per cent.solution) of hexose the 2 C.C. of iV/ 100-permanganate assuming the action C,H,,O + 2 0 = C,H,(OH),*CO,H + H*CO,H to occur are capable of oxidising 0.0009 gram of hexose if the reduction proceeds to the manganous state or 0.00054 gram if the action is arrested a t the stage of manganese dioxide. In the extreme cases therefore we have measured the time of oxidation of 0.9 per cent. of the sugar present in the solution, whilst on the other hand we have dealt with the time of oxidation of as small a proportion as 0.11 per cent. or less of the sugar present. The stock solutions of sugars and also the portions undergoing tests were maintained a t 2 5 O throughout 1416 ARMSTRONQ AND HILDITOH CONVERSION OF THE SIMPLE Neutral Solutions. The dye reagents are unaffected by any of the sugars tested in neutral solution.Under the conditions described permanganate is decolorised by fructose in four or five hours whilst with either form of glucose the solution becomes orange in about six hours, and fades to a full yellow tint after twenty-four hours. The behaviour of mannose is very similar to that of glucose. These results are obtained equally with fresh solutions and those which have remained for a day a t 25O. It may be of interest to state that i f the test is conducted in N / 10-sodium chloride solution instead of in water precipitation of manganese dioxide sets in a t a much shorter time; the figures obtained for fructose a-glucose and mannose were respectively 93 90 and 115 minutes. Acid Solutions. (i) Aqueous 8oEutions.-The oxidation times are constant a t any age of the solution in the case of acids.This is illustrated by the figures for fructose u- and &glucose and mannose given in table I. The dependence of the time factor on the hydrion concentration is shown by the results in table 11 wherein only the mean figures are quoted; it may be emphasised that the agreement of the individual readings a t varying ages of the sugar solutions is in all cases as good as those given in extenso in table I. Two series of times are given for each sugar the first being for the simple acid solution; the second gives the values obtained when the test-solutions were neutralised simultaneously with the addition of permanganate. I n the case of the higher concentrations of hydrogen ions investi-gated neutralisation of the acid present effected a t the same time as the addition of permanganate does not appreciably alter the oxidation times.A t the lower concentrations of hydrogen ions and notably with the weaker acids such as phosphoric and acetic the oxidation times for the ‘‘ neutralised ” solutions are quicker than for the acid solu-tions and progressively so as the strength of the acid decreases. The identity of the oxidation times for ‘‘ neutralised ” and for acid solutions with the stronger acid solutions is quite definite and we consider that they indicate the persistence of the active form of the sugar after neutralisation of the acid has taken place; the meaning of the results with neutralised solutions of weaker acids is by no means clear although they are explicable to a certai SUQABS INTO THEIR ENQLIU AND BITHYLENE OXIDE BOBMS.1417 extent when it is borne in mind that the sodium salts of the weaker acids will be appreciably hydrolysed so that we have really passed over in this instance to a feebly alkaline solution of the sugar. The age of the solution is given in hours the first reading (0.1 hour) having been taken immediately solution was complete ; in most instances this reading was commenced about three to five minutes after the addition of acid. The times of oxidation are in minutes unless an explicit statement to the contrary is added. TABLE I. One per cent. Sugars in NI10-HC1 and N/lO-H,SO,. Fructose. a-Glucose. 15-Glucose. Mrtnnose. A A A A Age. Acid.Neutd. Acid. Neutd. Acid. Neutd. Acid. Neutd. Acid. 0.1 17 15 29 27 30 30 13 12 HCI 1-0 16 17 28 29 32 30 12 13 2.0 17 18 31 28 32 27 12 12 5.0 16 18 29 - 34 29 12 17 0.1 31 24 52 41 - - 25 21 H,SO, 1.0 30 26 61 43 - - 23 20 2.0 28 22 51 42 - - 22 20 5.0 30 26 53 48 - - 24 21 TABLB 11. One per cent. Solutions of Fructose and a-Glzccose in Acids of Varying Strength. Hydrion concen-tration. Acid. per litre. Equivs. NIlO-HCl ......... 0.0910 N/lO-H,SO ...... 0.0660 NISO-HCI ......... 0.0188 N/60-H,SO ...... 0.0100 N/10-H8P04 ...... 0.0130 N/lO-C,H,O ...... 0.0012 Fructose. - Acid. Neutd. 16 17 30 24 69 62* 76 75* 211 84* 280 20* a-Glucose. - Acid. Neutd. 29 28 52 43 118 97* 124 75* 238 150* 1,070 65* * With precipitation.The hydrion concentrations are taken from data in Landolt and Barnstein's " Physikalische-Chemische Tabellen." (ii) Alcoholic Solutions.-Some observations were made in methyl- and ethyl-alcoholic hydrogen chloride solutions in view of the considerable amount of synthetic work which has been carried out in these media. Concentrations of N/20-acid were employed in order to approximate to the 0.25 per cent. hydrogen chloride golutions which have most frequently been used by E. Fischer 1418 ABMBTBONG AND HILDITOH CONVERSION OF THE 8TMPLE Irvine and other workers with theBe reagents. Very eimilar results were obtained to thosle found in aqueous solutions. The methyl alcohol wa6 distilled over lime and then over a little fructme whilst the ethyl alcohol was twice distilled over lime and potassium permanganate.Ten C.C. of the neutral solvents caused precipitation in the permanganate test in tsix hours in the case of methyl and in sixteen hours with ethyl alcohol. N/20-Methyl-alcoholic hydrogen chloride however decolorised the permanganate in ninety-eight minutes the time with N / 20-ethyl-alcoholic hydrogen chloride being fifty-six minutes, TABLE 111. One per cent. Solutions of Fructose and a-Glucose in Alcoholic N f 20-Hydrogen C’h2ori.de. Solvent. Age. chloride ................................. 0.1 2.0 3-0 24.0 chloride ................................. 0.1 2.0 3.0 24.0 N/20-Methyl-alcoholic hydrogen N /20-E thy1 - alooholio hydrogen Fructose. 7 17 25 6 7 8 6 -a - Gluc ose.11 16 120 9 20 10 23 -Alkaline Solutions. I n alkaline solutions it is also possible t o utilise the reduction of the dyes indigo and methylene-blue; the former gives two fairly definite colour stages passing from blue through green to a clear red and then changing t o pure yellow. The times occupied from the commencement of the test in reaching the standard red and yellow tints are given in the tables under the columns headed respectively (I R ” and ‘( Y.” I n both cases the dyes are restored by contact with air and it was found desirable to fill the upper part of the test-tubes with an inert gas hydrogen being employed. It W U ~ found that the stock alkaline sugar solutions whether maintained under air or under hydrogen behaved the same towards the three oxidising agents.The result of neutralising the alkaline sugar solution when the latter has been freshly prepared is t o cause a very marked retard-Methylene-blue fades to a colourless solution ation in reducing power but after the alkaline solution has remained for ~ome hours the reducing power after aeutralisation becomes greater approaching that of the slkaline solution itself in about twenty-four hours. Thie shows that initially the change induced by alkali is reversed on neutralisation but the progressive alteration in behavioup is somewhat obscure although it may well be due to the appearance of small amounts of decomposition products resulting from more profound disturbance of the sugar molecule. It is evident however that the behaviour of neutralised alkaline solutions is quite distinct from that of neutralised acid solutions, so that it may be considered that the cause of the reducing activity of the sugar is not the same in each case.The subjoined tables give the full series of readings up to five hours for fructose a- and 15-glucose and mannose in the presence of one and of two equivalents of sodium hydroxide (table W). I n table V are recorded the initial and final valuw (five hours) for fructose and a-glucose with varying concentrations of sodium hydr-oxide and in table VI we quote similar data for these sugars in the presence of one equivalent of a number of aqueous alkalie. Correlation of the Reducing Action of the Sugars with Alterationa in Optical Rotatory Power. In order t o obtain a convenient polarimetric reading in the 2-dcm.tubes employed the behaviour of 5 per cent. solutioxuj of fructose and of a-glucose was examined in neutral acid and alkaline media. The concentrations of the acid (NIlO-HCI) and of the alkali (N/18-NaOH) and the conditions of the reducing time-testa were otherwise maintained unaltered. The alteration in concentration of the sugars involved the determiqation of the corresponding times of reaction with permanganate and the dyes, and the results of these and of the observations of optical rotatory power are collected in table VII NaOH 2.0 equiv. 1.0 NaOH equiv. 2.0 1.0 TABLE IV. One per cent. Sugar Solutions with One and Two Equivalents (a) Tests with Potassium Permngamte. Age.0-1 1.0 3.5 6.0 24.0 0.1 1.0 3.0 5.0 24.0 Age. 0.1 1.0 3.0 6.0 24.0 0 1 1.0 3.0 5.0 24-0 Fructose. 7-A&. Neutd. 1.75 65*0* 1.25 60*0* 0.75 8.0 0.60 0.5 0.76 0.2 3.00 60-0.t 2-00 -1.75 65.0 1.25 11.0 1.25 0.25 a-Glucow. 7-Alk. Neutd. 10.0 61.0* 8.0 9o.o-f 3.0 160.0t 2.0 60.0t 1-76; 1.25 11.0 180.0t 7.5 -4.5 73.0* 3.0 48-0* 2.5 2-6 (b) Tests with Indigo and iliethylene-Indigo. Indigo. Indigo. Fructose. a-Glucose. A c < 7 r- - Meth. Meth. <-'-, R. Y. Blue. R. Y. Blue. R. 1.00 2.50 1-60 4.00 6.00 7.00 -0.75 1-25 0.50 3.25 6.50 4.00 -0.50 1-00 0.40 2.50 5.00 3.00 -0.60 1.26 0.35 2.25 5.00 2.25 -1.25 3.00 2.00 2.60 5-00 3.00 -8 l4 2.25 3.50 3.00 9.0 12.5 11.0 1.50 2.75 1.25 6.5 11.5 7-0 1.26 2.50 1-00 6.0 11-5 5.0 7 1.25 2-60 1.00 5-0 11.0 4.0 6 3.25 4-75 2.00 6-0 9.0 5.5 4 * Precipitation set in.t Indefinit TABLE V. One per cent. Solutions of Fructose and a-Glucose with Varying OH ion concn. per litre. 0-0978 -0*0506 -0.0383 -0.0256 -0.0 129 -Fructose. I / 7 Indigo. - Age. R. Y. 0.1 1-00 2.50 5.0 0-60 1.26 0.1 2.25 3.50 5.0 1.25 2.60 0.1 5.0 7.5 5.0 1-25 3.0 0.1 6.0 8.5 5.0 3.0 4.5 0.1 15.0T 20.0 5.0 7.0t 10.0 * Precipitation set in. Perrnqganate Meth. - Blue. Alk. Neutd. 1-50 1.75 65-0* 0.36 0.50 0.5 3.00 3-00 60-0t 1.00 1.25 11-0 5.0 5.0 56*0* 1.0 1.5 24.0 6.0 7.0 29*0* 3.0 3.5 19.o-f 17.5 14.0 50.0* 5-0 5.0 5l*O TABLE VI. One per cent. $olutions of Fructose and a-Glucose with One OH ion concn.Alkali. parlitre NaOH 0.0606 -KOH 0.0506 -Ba(OH) 0.0478 -NH,OH 0.0011 -Fructose. Indigo. - R. Y. 2.25 3-50 1.25 2-50 4.60 6-00 0.75 2-60 5.00 6.00 1-00 1.60 83.0 t 56.0 very little action. * Precipitation set in. Meth. Blue. 3-00 1-00 5-00 0.76 5.00 1-26 150.0 98-0 88.0t 60.0 Permangmate. - Alk. Neutd. 3-00 60t 1.2s 11 4.00 120t 1.25 60 4.00 -1.26; -304t 61* 16.0 20* 42.l)t 39* 27.0 27* 70.0 19* 48.0 so b *E R In 00 M -& I 1 M 0. 1424 ARMSTRONG AND HILDITOH (3ONVERSION OF THE SIMPLE er3 rl I c? r+ u3 90 Q * 90 cn * 8 * rl c3 ? + Q Q I I i 00 0 r+ t- Age in hours. 0-1 0 5 1.0 2.0 3.0 4.0 5-0 6.0 24.0 Age in days.2 4 8 12 25 (c) Solutions in N/ 18Sodium Hydroxide. Fructose. Glucose. Indigo. Permanganate. Indigo. Permanganate. - Meth. +Y - Meth. A R. Y. Blue. A&. Neutd. [a&,. R. Y. Blue. Alk. Neutd. 2.0 3.5 3.0 3.0 21 -89.7' 12 17+ 153 154 30 - - - - 89.2 - - I I -1.75 3.5 1-5 2.5 16 88.0 9 14 12 13 26 1-75 2.5 1.5 2.0 15 86.7 - - - - -- - - - - - 6 11 7 7 16i - - - - - 3 6 4 4 15 1.25 1.75 1-25 1.5 144 84.2 - - - - -- 1.0 1.6 1.0 1.5 9Q 83.3 - - - -1-75 2.25 2.0 1.5 1-0 81.5 3 74 5 5 One per cent. Solutdons of Fructose m d Glucose in Pyridine. In view of the interest attaching to the action of pyridine on the sugars a few experimenh were made with solutions of the two sugars in pure pyridine a t 25O.The pyridine was twice distilled over lime before use and boiled a t 116-116.5°. Ten C.C. of the distilled pyridine caused no alter-ation in the blue tint of indigo or of methylene-blue (2 C.C. of the staadard dye solutions) in twenty-four hours but with 2 C.C. r f N / 100-permanganate a precipitate appeared in three hours. The 1 per cent. fructose and glucose solutions in pyridine were also without action on the dyes but results analogous to those of the weaker alkalis were obtained with permanganate. These are given in table VIII in which the age of the solutions is in hours and the dewlorisation times in minutes as usual. TABLE VIII. One per cent. Solutions of Fructose and of a-Glucose in Pyriddne. Age. Fructose. a -Glucose. 0-1 30 not quite colourless 66 with very fine precipitation.1.0 23 , Y Y 40 9Y ,P I ¶ 9 9 2.0 17 , Y9 3.5 35 Y9 1 9 9 9 Y , 8.0 30 9s 9 ) 9 ) 9Y 6-0 8 , $ 9 4 4 12 y y 7 9 Comparative Experiments with Simple Aldehydes and Deriuatives of Ethylene Oxh?e. Some experiments-were made on the reducing action of aqueous solutions of acetaldehyde n-butaldehyde acetone and epichloro-hydrin and ethylene oxide. I n neutral 1 /18th gram-molecular solution all these substances with the exception of acetone caused the pink colour of the permanganate in our standard test to dis-appear within about two hours but the resulting clear orange solu-tion underwent no further change in colour for many hours. I n the case of acetone the pink tint did not entirely vanish for several hours. The resulh of the permanganate tests in iV/10-hydrochloric acid solution are given in the next table; in the case of ethylene oxide, the exact concentrations were not accurately known but tests were made with two strengths approximately gram-molecular per litre and 1 / 18th gram-molecular per litre SUGARS INTO THEIR ENOLIO AND ETHYLENIB OXfDB FORMS.1437 TABLE IX. SoJutions of Aldehydes and of Ethylene oxides in N/ 1Q-Hydrochloric Acid. Concn. Permanganate tests. A / \ Acid. Neuldhd. 1.0 64 hrs. y y Y 7 9 Y, 3.0 2 hm. , 9 10 9 1 ?? 1.0 24 hrs. y; Y 10 Y $9 3-5 24 hm. ,) Y 10 , ,, 24-0 2& hrs. , ¶ I 10 9 1) P r Substance. htre. Age. Acetaldehyde ,.. M/18 0.1 64 hrs. Pale yellow 9 minutes with pptn. n-Butaldehyde ... M/18 0.1 34 hrs. Pale yellow 13 minutes with pptn.Epichlorohydrin M/18 0.1 140 minutes. 82 minutes. 1.5 120 s y 53 S# 4.3 90 y 35 ,Y 24.0 120 , 32 9 , 1.0 132 , 89 ,* 3.0 130 , 80 99 23.0 110 y 20 ¶ S 1.0 12 , 13 ,, 2.0 17 , 14 9 9 6.0 16 ) 14 s, 23.0 15 , 14 9, Ethylene oxide ... M/18 0.1 103 minutes. 80 minutea. M 0.1 8 minutes. 10 minutes. Table X illustrates the data obtained in N/18-aqueous sodium hydroxide ; with both aldehydes acetone and epichlorohydrin and ethylene oxide indigo passed rapidly through green to a pale yellow colour and the original blue tint could not be restored by shaking the yellow solution with air. It appears therefore that some action was proceeding in these cases beyond simple reduction to indigo-white and the colour test is not valid in this instance.TABLE X. Solutions of Aldehydes and of Ethylene Oxides in N/18&d6um Hydroxide. Concn. Permang;enate. Per Methylene-Substance. litre. Age. blue. Alkaline. Neutralised. 11* 11* 6* 60 16* 30 16* 18 6* 1 Acetaldehyde .,.,.. M/18 0.1 sot 1.0 32t 3.5 21 t 5.0 23t 23.0 351. * Precipitation set in. t Indefinite end-point 1428 CONVERSION OF THE SIMPLE SUGARS ETC. TABLE X . (continued). Solutions of Aldehydes and of Ethylene Oxides in N/ 18-Sodium Hydroxide. Concn. P r Substanoe. htre. Age. n-Butddehyde.. . . . . . . M/18 0.1 1.0 3.5 5.0 23.0 Acetone ..... ... .......... M/18 0.1 ;:;I 5.3 23.0 Epichlorohydrin . . . . . . M / 18 0.1 1.5 4.3 24.0 Ethylene oxide . . . . . . M/18 0.1 1.0 3.0 23.0 M 0.1 1.0 2.0 6.0 23.0 Methylene -blue. 20 14 12 13 .39t Permanent. Permanent. 9 9 9 9 9 9 Permanent. 9 9 9 9 9 s Permanent. 9 s 9 9 9 ) 9 9 Permanganate. Alkaline. Neutrali&d. 8* 8* 6* 8* 7* 7* 8* 8 19* 2 Pale green, then turbid yellow. 113* loo* 95* 80* 245t 236t 174t 220t 76t 7 55 19* In 16 hours, precipitation, but still pink. 207 140 110 110 352 350 340 320 87 84 88 77 63 * Precipitation set in. j- Indefinite end-point. The most interesting points in this series of experiments are: (i) The alkaline solutions of the aldehydes reduce methylene-blue similarly to the sugars and there is some similarity in their behaviour to alkaline permanganate. (ii) The ethylene oxide derivatives show no similarity to the sugars in alkaline solution either with respect t o permanganate or to methylene-blue. (iii) On the other hand the acid solutions of the ethylene oxide compounds display great likeness to those of acid sugar solutions, both in the (( acid ” and “ neutralised ” permanganate tests. WARRINUTON. [Received November 13th) 19 19.

ISSN:0368-1645    

DOI:10.1039/CT9191501410

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

THE CONSTTTUTfON OF THlll NITROPRUSSIDES. 1429 CXXXIV. -The Constitution of the Nitroprussides. Part I. By GEORGE JOSEPH BURROWS and EUSTACE EBENEZER TURNER. FROM time to time the nitroprussides have been made the subject of considerable speculation but little attempt has been made to verify experimentally the various constitutions assigned to them. Hofmann who is responsible for most of the experimental work in this field (Amnalen 1900 312 1) assigned to sodium nitro-prusside the co-ordination formula [Fe(CN)’),NO]Na,. Friend (T., 1916 109 721) apparently without further experimental work, proposed for potassium nitroprusside the formula (I). Conductid y and Cryoscopic Measurements. (1.) (11.) This formula corresponds with the empirical one given in works of reference (for example Moissan ‘‘ Trait6 de chimie minerale,” 1905 417) which formula however seems never to have had any evidence in its favour.Friend a t the same time rejected the formula (11) suggested by Browning (T. 1900 77 1238) for potassium nitroprusside in view of his theory as to the constitution of the ferrocyanides which theory has since been shown to be unnecessary (Bennett T. 1917, 111 490). It was suggested by one of us (T. 1916 109 1130) that a deter-mination of the molecular weights of some nitroprussides would throw light on the problem and as a result a number of nitro-prussides have been prepared and investigated cryoscopically and their conductivities measured. From the results so obtained the number of ions present in a solution of a nitroprusside has been calculated and conclusioiis have been drawn as t o the molecular weighh of the salts in question.I n these experiments the degree of dissociation of the salt at any particular dilution was found in the usual way by dividing the molecular conductivity at that dih-tion by its value a t infinite dilution. From cryoscopic measure-ments the molecular depression of the freezing point of water was found for various concentrations of the salt and by dividing this number by 18.7 (the molecular constant for water) the value fo 1430 BURROWS AND TVRNBR: i (the van’t Hoff coefficient) was obtained. The number of ions, k into which each molecule of the salt dissociates was thm obtained by aubdituting the experimental values of a and i in the equation i=l+ (k- 1)a.A similar method was used by Petersen (Zeitsch. physikal. Chem. 1902 39 249) in connexion with the cobaltamminea. This author was of the opinion that the conclusions drawn by Werner (Zeitsch. physikal. Chem. 1893 12 35 etc.) from measurements of the molecular conductivity at a dilution of 1000 litrea (not necessarily a t infinite dilution) were in most cases inaccurate. The figures given by Jones (Carnegie Znstitute of Washington, Publication No. 170) for the molecular conductivities of a large number of salts show that most salts are completely dissociated a t dilutions of about 1000 litres. In some cases however the mole-cular conductivity again increases beyond that dilution owing t o causes other than dissociation. From the figures given by Petersen (Zoc.c i t . ) for the conductivity of the cobaltammines it would appear that similar difficulties arose in his work. I n the present investigation the substances considered are salts of a strong acid. (This has been found to be the case from a pre-liminary examination of the molecular conductivity of nitroprussic acid itself.) The conductivities of the salts were determined for solutions diluted to 2048 litres and the values were plotted against the concentrations. The value for infinite dilution was found by extrapolation from the curve so obtained. I n all cases the value of pa differs only slightly from the value actually found for plOx a result which was expected from the nature of the salts in question. In the following tables are given the values of k calculated on the assumption that the nitroprussides are represented by the simple formula M,’[Fe(CN),NO] which will be referred to in future as type I.I n addition the value of k has been calcu-lated in each case for a molecule M4~[Fe2(CN),,(NO),1 (type 11). In the case of a dnivalent cation a molecule of type I will dissociate into three ions type I1 giving five ions. The value of k should therefore approximate to 3 if formula I is correct whilst if I1 is correct k,=5. In the same way a salt of a bivalent cation should give the values k = 2 or kl = 3. It is considered that the results obtained show conclusively that all the nitroprussides examined conform t o the simple formula (type I). They are salts of H,[Fe(CN),NO] and not of The possible effect due to hydration of the ions has not been over-looked (compare Jones Camegie Institute of Waahdngton Publi-H,[Fe*(CN) ,dNO) THE CONSTITUTION OF THE NITROPRUSSIDES.PART I. 1431 cation No. 180) and it is considered that the conclusions drawn from the figures obtained in the preseht work cannot be regarded as vitiated on this ground. Whereas hydrate formation may account for the differences between the experimental and absolute values of k the extremely large differences in the case of k cannot be accounted for in this way. It is hoped in a future communication to describe the alkyl nitroprussides some of which have been prepared although in an impure state only. EXPERIMENTAL. The conductivity measurements were all made a t 25-0°. The degree of dissociation of salts a t Oo differs only slightly from that a t 25O and the latter temperature allows of greater accuracy in determining the conductivity.In the following tables v i8 the number of litres containing one gram-molecule of the salt (calcu-lated for the simple formula I) p is the molecular conductivity, a is the degree of dissociation and is equal to pu/pLoo At is the observed depression of the freezing point of water MAt is the molecular depression and is equal t o v x At x 10 i is the van't Hoff coefficient and is equal to MAt/18-7 and k is the number of ions into which a molecule dissociates and is obtained from the equation i= 1 + (k - 1)a; k is the corresponding value of L calculated for a molecule of type I1 by doubling i and then substituting in the equation i = 1 + (k - 1)a.The values of a in the cryoscopic tables are taken from the curves obtained from conductivity data. Sodium Nitroprusside Na,[ Fe (CN),NO] 2H,O. The salt used was a pure specimen. Conductivity Measurements . 0. 4 8 16 32 64 228 266 512 1024 2048 00 P-168.2 169.4 181.8 194.3 204.9 214.2 222.0 229.2 244.6 246.0 286.2 a. 0.63 0.69 0.74 0.79 0.84 0.87 0.91 0.94 0.96 - 1432 BURROWS AND TURNER: Cryoscopic Measzcrements. 2 At. MA,. 47.1 0-115 54.1 24.4 0-218 53.2 14.56 0.348 50.2 10.81 0.466 49.3 8.76 0.660 49.1 7-12 0.678 48.3 Type I reqUim k=3. i. a=k/pa,. b. 2.90 0.81 3.35 2.84 0.77 3.40 2-68 0.73 3.30 2.64 0-71 3-30 2.62 0.70 3-31 2-68 0.68 3.32 Type I1 requires IC = 5.kl. 6.9 7.1 7.0 7.0 7.0 7.1 Potassium Nitroprusside Kz[Fe(CN),NO]. This salt was prepared by decomposing the barium salt with the calculated weight of pure potassium sulphate filtering off the barium sulphate and evaporating the filtrate a t a low temperature under diminished pressure. The residue so obtained was crystal-lised from aqueous alcohol containing about 95 per cent. of alcohol. It crystallises in pale pink crystals without water of crystallisation : C,ON,FeKz requires Fe = 19.0 per cent. 0'4010 gave 0.1076 Fe,O,. Fe = 18.8. v. 8 16 32 64 128 256 512 1024 2048 a0 Coductivit y Measurements. P* 199-2 206.2 215.7 227-2 236.6 244.0 249-3 257.0 2584 258- 1 a. 0-745 0-795 0.836 0.881 0.917 0.946 0-966 0-996 --v.34.4 24.1 14.66 11.65 7.02 4.78 Cryoscopic Measurements. At. MA,. i. a=pJFa,. k. kl. 0.160 51.6 2.76 0.85 3-07 6.32 0.213 61.3 2.74 0.82 3.12 6.46 0-316 46.3 2.48 0.79 2-87 6.01 0.405 47.2 2.52 0.77 3.00 6.25 0.641 45.0 2.41 0.74 2.91 6.16 0.909 43.4 2-32 0.71 2-86 6-11 Type I requires k=3. Type I1 requires k1=6. Barium Nit ropusside B a[ Fe (CN) ,NO] ,3 H20. This salt was prepared by precipitating a solution of the sodium salt with zinc sulphate and boiling the zinc salt so obtained with a suspension of precipitated barium carbonate. The filtered solu-tion of the barium salt was evaporated under diminished pressur THE CONSTITUTION OF THE NXTROPRUSSIDES. PART I. 1433 a t a low temperature and the salt crystallised from aqueous alcohol : 0.8344 gave 0'4734 BaSO,.C,0N,BaFe,3H20 requires Ba = 33.7 per cent. The anhydrous salt was found to be extremely hygroscopic. Conductivity Measurements . Ba= 33.4. v. 8 16 32 64 128 256 612 1024 2048 00 v. At. 37-7 0.093 16.6 0.180 9.87 0.285 6.67 0.413 4.73 0.575 P. 152.9 165.9 177.1 190.7 203.0 216-2 223.6 236.9 240.6 243.0 a. 0.63 0.68 0.73 0.79 0.84 0.89 0.92 0-98 -Cryoscopic Measurements. MA+. i. a = ~ l p m . b. k,. 35.1 1-88 0.74 2-19 4.73 29.7 1-59 0.68 1.87 4.21 28.1 1.50 0.64 1.78 4.13 27.6 1-47 0.61 1-77 4-18 27.2 1.45 0.59 1.76 4.22 Type I requires E= 2. Type I1 requires k,= 3. This salt is of especial interest owing to the rough equality in weights of the anion and cation.Ammonium Nitroprusside (NH,)2[Fe(CN),NO]. This salt was obtained by decomposing the barium salt with an equivalent weight of ammonium sulphate filtering evaporating under diminished pressure and crystallising from aqueoug alcohol, when reddish plates very readily soluble in water were obtained : C,ON,Fe(NH,) requires Fe= 22.2 per cent. 0-2390 gave 0.0768 Fe,O,. Fe = 22.5. v. 16 32 64 128 266 512 1024 2048 Qo Conductivity Measzcr ements. P* 206.7 218.0 228.5 236.7 246-6 251.2 261.3 266.2 268.0 a. 0.77 0.82 0.86 0-89 0.92 0-94 0.98 1434 BURROWS AND TURNER: Cryoscopic Measurements. V. At. MA,. i. a=k/pao. k. kl. 26.3 0.214 56.4 3.01 0.80 3.51 7.27 10.73 0.460 48.3 2-60 0.74 3-18 6.62 6.68 0.704 47.0 2-61 0.69 3.19 6.83 Type I requires k= 3.Type I1 requires k,= 6. Methylammonium Nitroprusside (MeNH&[Fe(CN),NO]. This salt and the diroprussidea of di- and tri-methylamine were obtained by treating a solution of the free acid (obtained from the barium salt and the calculated sulphuric acid) with a slight excess of an alcoholic solution of the amine. The solution so obtained was evaporated under diminished pressure and the solid residue crystallised from alcohol. The alkylammonium nitro-prusaidea crystallise in reddish plates which are very readily soluble in water. In appearance they resemble the barium or ammonium salts : 0*1117 gave 0.0306 Fe,O,. Fe=19'2. C,ON,Fe(MeNH& requires Fe = 20.0 21.32 64 128 258 512 1024 a 0. At-36.6 0.148 19.06 0-262 14-16 0.339 10.13 0.466 8.36 0.641 Conductivity Measurenwnts. P-185.2 197.7 208.0 218.5 226.8 233.4 240.0 Cry oscopic Measurements . MA,. i. a=pJpoo. 64.2 2.90 0.78 49.9 2.67 0.71 48.0 2-57 0.68 47.2 2.62 0.62 46.2 2.42 0.59 per cent. a. 0.77 0.82 0.87 0.91 0.94 0.97 -k. kl. 3.45 7.2 3.36 7.1 3-31 7.1 3.46 7.5 3.41 7.6 Type I requires k = 3 . Type I1 requires bl=B. Dimethylammonium Nitroprusside (Me2NH,),[Fe(CN),NO]. C,0N6Fe(Me,NH,) requires Fe = 18-1 per cent. 0.1028 gave 0.0272 Fe,O,. Fe= 18.5 THE CONSTITUTION OF THE NITROPRUSSIDES. 1435 21. 16 32 64 128 256 512 1024 2048 Conductivity Measurements. P. 156.5 172.1 185.2 196.3 205.8 212.5 220.2 227-3 230-0 a. 0-68 0.75 0.81 0.85 0.90 0.92 0.96 1 Cryoscopic Measurements. er. At. MA*. i. a=pufpm. k. k,. 35.2 0.149 52.4 2.50 0.76 3-37 7.05 16.4 0.294 48-1 2.57 0.68 3-31 7-09 8-84 0.500 44.2 2.36 0-Gl 3-23 7.10 5-92 0.714 42.3 2-26 0.57 3.2 1 7.20 Type I requires k = 3. Type I1 requires k = 5. Trimethylammonium Nitroprusside (Me3NH)2[Fe(CN),NO]. 0.2234 gave 0.0512 Fe,03. Fe = 16.0. C,ON,Fe(Me,NH) requires Fe = 16.7 per cent. v. 16 32 64 12s 256 512 1024 2048 00 Conductivity Measurements. P* 137.1 154.0 167.3 183.0 191-7 201- 1 208.0 210.5 212.0 a. 0.65 0.73 0.80 0-86 0.90 0.95 0.98 -cryoscopic Measurements. V . At. MA,. i. a=pVlpm. k. kl. 39.0 0.134 52.2 2.79 0.75 3.39 7.11 14.47 0.290 42.0 2.24 0.63 2.97 6.52 6-56 0.588 38.6 2.06 0-50 3.12 7.24 Type I requires k = 3. Type II requires k,= 5. THE UNIVERSITY CHEMICAL LABORATORIES, SYDNEY. [Received November lst 1919.1 VOL. cxv. 3 T

ISSN:0368-1645    

DOI:10.1039/CT9191501429

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

1436 PAYMAN THE PROPAGATION OF FLAME IN cx XXV.-The Propagation of Flame in Complex Gaseous Mixtures. Part 1. Limit &fixtures and the Uniform Movement of Flame in such Mixtures. By WILLIAM PAYMAN. IN order that flame may propagate through a mixture of an in-flammable gas with air or oxygen the heat developed by a given “layer” on burning must be sufficient to raise the contiguous layer of unburnt gas t o its ignition temperature. In a “limit mix-ture ” there is just sufficient and only just sufficient heat developed to accomplish this. If limit mixtures -of two or more inflammable gases be mixed together this heat balance should remain un-altered provided that all of the limit mixtures are of the same kind that is t o say all lower-limit or all upper-limit mixtures.It follows that all mixtures in any proportions of limit mixtures should remain limit mixtures the limiting percentage being that of the mixed inflammable gas. Conversely any limit mixture of a complex inflammable gas will consist of a number of limit mixtures of the individual gases it contains. Assuming this reasoning to be correct imagine a limit mixture with air of a complex inflammable gas. . . . be the simple constituents of this inflammable gas and their limits of inflammability N, ,VB N, . . . respectively. Suppose also that the complex limit mixture contains a per cent. of A b per cent. of B c per cent. of C . . . Then this limit mixture will contain Let A B C, aA + bB + cC + . . . + [lo0 - (a + b +c + . . .) J air. ‘This limit mixture ex hypothesi comprises a series of limit mix-tures of the simple inflammable gases.I n such a simple limit mixture of A for example every N parts of A are associated with 100-Nd parts of air so that every a parts of A are associated with (T) loo - N~ a parts of air. Similarly for B C . . . The complex limit mixture will therefore contain Since these terms equal 100 so that b+(E!-$)b G + c . . . (‘oO.zi“rJ,N”) are expressed as percentageg they will together c + . . * =loo. 100 - N,‘ 100 -&‘ b + c + a + ( N )a+b+(T-) (7 COMPLEX GASEOUS MIXTURES. PART I. 1437 This expression on simplification becomes This is the formula of Le Chatelier which has been shown to apply accurately for both the upper and lower limits of inflamma-bility of a number of complex gaseous mixtures with air (Coward, Carpenter and Payman this vol.p. 27). This “formula,” but not the generalisation from which it has been deduced applies only to mixtures of inflammable gases with an atmosphere of constant composition such as air. For the numerical quantities involved in the formula relate to the com-bustible gases only and admit of no allowance being made for variations in the proportions of inert gas present. The general-isation however should hold good for all limit mixtures; for mixtures in which t.he proportion of inert gas is greater or less than in air or even in which its proportion is not constant.* The effect of an inert gas (nitrogen) on the limits of inflamma-bility of methane has been investigated by Burgess and Wheeler (T. 1914 105 2596) who determined the limits for this gas in several artificial atmospheres of oxygen and nitrogen containing less oxygen than air.During the course of the present inquiry into the mode of combustion of mixed gases it became necessary to extend their work to include atmospheres containing more oxygen than air and pure oxygen. The method of experiment used by Burgess and Wheeler which involved the central ignition of the mixtures in a large globe was not employed in the present research. This investigation is mainly concerned with the uniform movement of flame and the deter-minations of the limits were made in the same apparatus as was used for measuring the speed of propagation of flame. This con-sisted of a horizontal glass tube 2.5 cm. in diameter open a t one end and closed a t the other the mixtures being ignited close to the open end of the tube by means of an electric spark.The criterion of inflammability was theref ore the horizontal propaga-tion of flame throughout the length of the tube. ‘The determinations were carried out by the method of trial and error using mixtures which differed in composition by about 0.10 per cent. of methane. Throughout this paper the term ‘‘ limit mixture,” whether upper or lower implies that mixture in which flame was just able to propagate. The limits were always sharply defined. On sparking a mixture con-The results of the determinations are given in table I. * This will be described in future as the *‘ limits generalisation.” 3 ~ 1438 PAYMAN THE PROPAGATION OF FLAME IN taining a little less than the lower-limit percentage of inflammable gas there usually arose a ball of flame which travelled some 5 or 6 cm.along the tube. A mixture containing slightly more in-flammable gas than the higher-limit percentage usually produced a flame which travelled the short distance from the spark to the open end of the tube owing to the dilution of the mixture there by diffusion of the outside air. In the limit mixtures flame travelled steadily and a t an approximately uniform speed through-out the length of the tube. I n no instance did the flame of the burning limit mixture fill the whole cross-section of the tube but it was usually similar to the trailing flames described by Burgess and Wheeler (T. 1914, 105 2593). This was most marked with the upper-limit mixtures and with the lower-limit mixture of methane in pure oxygen.These flames were about 10 mm. in diameter and about 15 mm. long and had a short tail resembling a “Prince Rupert’s drop” in shape. In three instances the deposition of carbon was noticed during the passage of flame through a limit mixture namely in the upper-limit mixtures of methane with atmospheres containing 50 66, and 100 per cent. of oxygen.* The flames resembled that of a tallow candle and the odour of the residual gases was similar to that caused by the smouldering wick of such a candle. I n general, the upper-limit flames were olive-green in colour. The colour of the lower-limit flames was pale blue. TABLE I. The Limits of Inflammability of Methane in Mixtures of Oxygen and Nitrogen.Percentage of oxygen in atmosphere. 13.7 17.0 21.0 (air) 33-0 50.0 66.0 100.0 c CH,. 6-4 6-1 5.8 5.8 5.8 5.8 5.7 Percentage composition of limit mixtures. , A Lower limit. Upper. P - 0 2 - N2. CH,. 0 2 . 12.8 80.8 6-9 12.7 16.0 77.9 8.9 15.5 19-8 74.4 13-3 18.2 31-4 62.8 25.1 25.0 47.1 47.1 38.8 30.6 62.8 31.4 47.5 35.0 94.2 - 59-2 40.8 7 N 2’ 80.4 75-6 68-5 49.9 30.6 17-5 -* According to Bone (Phil. Trans. 1915 215 275) when methane and oxygen mixtures are exploded under pressure “ there is EL total cessation of any separation of carbon (which is very marked with mixtures 2CH + 0,) after the proportion of oxygen in the original mixture exceeds the limit 3CH + 20,.” No carbon was deposited when a mixture containing 59.3 pe COMPLEX GASEOUS MIXTURES.PART I. 1439 0 0 30 The results are plotted in the diagram the ordinates representn-ing percentages of methane and the abscisse percentages of oxygen in the limit mixtures. If the “limits of generalisation ’’ given earlier in this paper applies to these mixtures the values for each of the two sets of limik should lie on a straight line. It will be seen that this holds accurately over a large range of mixtures namely over those con-taining more than about 17 per cent. of oxygen.” Mixtures con-taining less than this amount of oxygen require rather more methane than the theoretical quantities to attain both the upper and lower limits. 0 40 I Oxygen in limit mixture per cent.The dotted lines in the diagram represent the values obtained by Burgess and Wheeler (Zoc. cit.). The shapes of both curves are cent. of methane and 40.7 per cent. of oxygen was exploded under a pressure of 12.7 atmospheres. In the present series of experiments a t atmospheric pressure a mixture of approximately the same composition as that used by Bone (59.2 per cent. of methane and 40.8 per cent. of oxygen) deposited carbon as did also mixtures containing less oxygen in proportion to the methane present, namely those intermediate in composition between 3CH4+20 and CH,+ 0,. It would therefore appear that the limiting composition at which the deposi-tion of carbon ceases is not fixed but varies with the initial pressure of the mixture.* According to Burgess and Wheeler (Zoc. cit.) no mixture of methane, oxygen and nitrogen is capable of propagating flame when there is less than about 13 per cent. of oxygen present 1440 PAYMAN THE PROPAQATION OF FLAME IN similar the difference in magnitude being due to the difference in experimental conditions. Little change was observed in the lowe; limit until the mixtures contained a large excess of nitrogen; whilst the value with pure oxygen was only slightly lower than that with air. The latter observation is not in agreement with the results recorded by Parker (T. 1914 105 lOOZ) who found the lower limit of inflammability of methane to be slightly higher with oxygen than with air (6.0 per cent. and 5-8 per cent. respectively). The apparatus used by Parker was similar to that previously used by Burgess and Wheeler namely a 2-litre globe in which the mixtures were ignited a t the centre.This lack of agreement is undoubtedly due to the difference in the position of the point of ignition in the two sets of experiments. It has frequently been noted that the limits of inflammability vary with the position of the point of ignition according as the flame has to pass upwards or downwards through the gas mixture. The fact that a flame will pass more readily upwards than downwards is well illustrated when a lower-limit mixture of methane in air, for example is ignited by a spark a t the centre of a globe. As soon as the spark passes a flame shoots to the top of the vessel, bends over and then moves slowly downwards to the bottom.I n order to investigate this point further a series of experiments was carried out to determine quantitatively the effect of varying the point of ignition on the limits of inflammability of methane in air and in oxygen. A glass tube 2.5 cm. in diameter was used, closed a t one end and fitted with firing points a t the other (open) end. TABLE 11. Limits of ZnfEarnmability of Methane with Bifferent Positions of the Point of Ignition. Percentage of methane in lower-limit mixture. - Mode of propagation. Air. Oxygen. Upward ........................ 5-5 5.4 Horizontal ..................... 5.9 5.8 Downward .................. 6.1 6.3 Central ignition (Parker). . 5-8 6-0 Both for upward and horizontal propagation the lower limit of inflammability of methane is less in oxygen than in air.Bor downward propagation however the order is reversed. The differences observed are not very great although too large to be accounted for by experimental error. Of the factors which deter-mine the value of the limiting percentage of inflammable gas th COMPLEX GASEOUS MIXTURES. PART I. 1441 transference of heat by convection and the absorption of heat by the mixture may be mutually opposed. During the downward propagation of flame convection does not materially affect the transference of heat to unburnt layers of the mixture; the influence of the slightly higher specific heat of oxygen as compared with that of nitrogen therefore becomes apparent. With horizontal and upward propagation of flame however the influence of con-vection currents masks the effect of the higher specific heat of oxygen.The change of order of the results dependent on the direction of travel of the flame is more marked when the results for methane in air are compared with those for hydrogen. Such a comparison is made in table 111. TABLE 111. Lower Limits of Inflammability in A.ir of Methane and of Hydrogen. Percentage of inflam-mable gas - Mode of propagation. Methane. Hydrogen. Upward ........................ 5-5 4.2 Horizontal ..................... 5.9 6-2 Downward .................. 6.1 9.7 Central ignition ............ 5.8 9.2 Attempts have been made to calculate the limits of inflamma-bility of a gas from its thermal constants. It will be clear from a consideration of the results recorded in table I11 that any such calculation is doomed to failure unless allowance can be made for the influence of convection currents.Since the lower limit of inflammability of methane (downward propagation of flame) is less with air than with oxygen it might be expected to be less still with an atmosphere containing less oxygen than air. The lower limit of inflammability of methane in an atmosphere containing 17 per cent. of oxygen was found to be 6 . 3 per cent. for downward pro-pagation of flame. This limit is thus affected in the same sense as both ICmits for horizontal propagation in mixtures containing only a small percentage of oxygen; that is t o say more methane is required to form the limit mixture than would be expected from results with mixtures richer in oxygen.This displacement of the range of inflammability corresponds with the displacement of the range for maximum speed of uniform movement of flame in mixtures of methane and air. It has been generally assumed that the latter displacement is due to the higher thermal conductivity of methane as compared with that of air. A This however is not so 1442 PAYMAN THE PROPAGATION OF FLAME IN similar displacement is found however when the inflammable gas has a thermal conductivity less than that of air as will be shown in a subsequent communication. The displacement under con-sideration in the present paper and other similar displacements, have one feature in common namely that the mixtures contain a large proportion of inert gas (nitrogen) together with only a slight excess of one or other of the reacting gases above the quantity required for complete combustion.A possible explanation of the results is that the mode of com-bustion in such mixtures differs from that in mixtures containing a large excess of either of the reacting gases. Such an explanation is supported by the analyses of the “flame gases” recorded by Burgess and Wheeler in the paper to which reference has already been made. The samples of gas were rapidly snat,ched from the flames in such a manner as to cool the primary products of com-bustion before secondary reactions could come into play. It will be seen on examining the table of analyses (p. 2604) that all mix-tures containing less than 15 per cent. of oxygen appear to be influenced by the deficiency of reacting gas (whether methane or oxygen) and it is in these mixtures that the generalisation regard-ing limiting percentages no longer holds.With the upper-limit mixtures of low oxygen content the primary products of combus-tion contain smaller quantities of hydrogen than of carbon mon-oxide whereas with the higher-limit mixtures containing a greater proportion of oxygen the quantities of hydrogen and carbon mon-oxide produced are equal. Similarly with the lower-limit mixtures of low oxygen content, the primary products of combustion contain more carbon monoxide than hydrogen whilst with lower-limit mixtures containing more than 15 per cent. of oxygen these gases are absent altogether from the products of combustion. Further consideration of these results is reserved for a future ,communication as is also the consideration of the displacement of the range for maximum speed of uniform movement of flame in mixtures of air with inflammable gases.The Unifoym Movement of Flanae in Linzit Mixtures. !l!he speed of horizontal propagation of flame in the limit mix-tures in a tube 2.5 cm. in diameter was determined by the method described by Wheeler (T. 1914 105 2606). The results are given in table IV COMPLEX GASEOUS MIXTURES. PART I. 1443 TABLE IV. Speed of Propagation of Flame in Limit Mixtures of Methane, Oxygen and Nitrogen in a Tube 2.5 cm. in Diameter. Percentage of oxygen in atmos-phere. 13.7 17.0 21.0 (air) 33.0 50.0 66-0 100.0 Speed in cm. per sec. - Lower limit.Upper limit. 21.9 19.1 22.4 19.0 23-3 19.1 23-0 18.9 22.8 18.9 21-3 19.4 19.9 18.9 'The upper-limit speeds are identical within the range of experi-mental error. The speeds in the lower-limit mixtures are through-out slightly higher than the corresponding upper-limit speeds, although with pure oxygen the difference is very small. A notice-able feature of these flames common to them all was their small size in comparison with the diameter of the tube. This was more marked with the flames in the upper-limit than in the lower-limit mixtures a fact which no doubt accounts for the slower speed of the former flames. For the smaller the flame the greater is its surface in proportion t o its volume and the greater in proportion is the transference of heat from the flame to the walls of the tube.I f this explanation be correct it follows that the speeds of flames in limit mixtures should increase with increased diameter of the tube in which they travel. This was found to be so by Mason and Wheeler (T. 1917 111 1052). With tubes of very small diameter on the other hand the speed of flame a t the limits is comparatively high (Payman and Wheeler, T. 1918 113 656) but for another reason. With such tubes the cooling effect of the walls is so great as to have a marked effect on the value of the limits the range of inflammability of the mixtures rapidly narrowing as the diameter of the tube is diminished. Moreover convection currents have no appreciable influence in tubes of such small diameter. It seemed probable that! the speed of flame in a limit mixture, determined under standard conditions should approach a constant value irrespective of the nature of the inflammable gas.To test this the speeds of flame have been determined in limit mixtures of air with several of the paraffin hydrocarbons. The results are given in table V which is of value also in recording the limits of inflammability (horizontal propagation of flame). The limits differ slightly from those found (central ignition in 3 H 1444 PAYMAN THE PROPAGATION OF FLAME IN a large globe) by Burgess and Wheeler whose results are inserted in the table in brackets. I n the upper-limit mixtures the flames vibrated rapidly about half-way along the tube and were sometimes extinguished there. The difference between a limit mixture and one which could only propagate flame for a short distance if a t all was however well marked.TABLE V. Limits of Inflammability and Limiting Speeds of Flame in Mixtures of Air with the Parafin Hydrocarbons in a TuBe 2.5 cm. in Diameter. Lower limit. Upper limit. 7- - Per cent. of Speed cm. Per cent. of Speed cm. Hydrocarbon. combustible. per sec. combustible. per sec. Methane CH ......... 5.8 (5.6) 23.3 13.3 (14.8) 19.1 Ethane,*C,H ......... 3.3 (3-4) 18.1 10.6 (10.7) 19-7 Propane C3H8 ......... 2-4 (2.3) 20.8 7.3 ( 7.3) 20.3 Butane C,H, ......... 1.9 (1-6) 20.1 6.5 ( 5.7) 20.3 (CH + C,H,,*) ...... 2.6 (2-5)t 22.3 7-7 ( 7*7)t 20-7 * Equimolecular mixture of methane and pentane. -f Calculated from values for methane and pentane.Pentane C,H, ......... 1.6 (1.4) 20-2 5-4 ( 4.5) 20.2 The “limit speed” is thus found t o approach a constant value, as foreshadowed by Burgess and Wheeler (T. 1914 105 2596), not only with each of the paraffin hydrocarbons singly but also with the mixture of methane and pentane. There is no reason to doubt but that the limit speed of flame would have the same value for any mixture of the paraffins. The speeds of flame in limit mixtures with air of carbon mon-oxide and hydrogen have also been determined. With carbon monoxide the speed a t both limits (in a tube 2.5 cm. in diameter) is 19-4 cm. per second which agrees well with the speeds for the paraffins. With hydrogen the speed at the lower limit is remark-ably slow namely 10 cm. per second.The flame is exceedingly small consisting of a tiny ball of flame which however travels the full length of the tube. For reasons given in a previous com-munication (this vol. p. 41); it was not found possible to determine accurately the speed of flame in the upper-limit mixture of hydrogen and air, The equimolecular mixture of methane and pentane corresponds with propane in percentage composition and calorific value and yields the same products on complete combustion. The marked difference between the limits of inflammability of the mixed gases and those of propane shows that these are not the only factors on which the limit,s of inflammability depend. Similarly a mixtur COMPLEX GASEOUS MIXTURES. PART I. 1445 of three volumes of pentane and two volumes of hydrogen corre-sponds with propane but this mixture of gases has limits 2-5 (lower) and 8.6 (upper) as compared with propane 2.4 and 7.3.These differences are perhaps due to the ability of the con-stituents of the mixed inflammable gases to burn independently. This subject will be dealt with more fully in succeeding papers of this series. EXPE~RIMENTA L. The speeds of propagation of flame in limit mixtures were deter-mined in glass tubes by the method described by Wheeler (T., 1914 106 2610). Two tubes were employed both 2.5 cm. in diameter; one 3 metres long used for the majority of the experi: ments; the other used for the mixtures with atmospheres rich in oxygen was only 1.5 metres long so as to avoid the setting up of the detonation wave with consequent shattering of the tube.The platinum firing points were about 2 cm. from the open ends of the tubes. At measured distances along each tube were fused ground-glass tubulures which carried glass plugs with stout platinum wires fused through them. Fine " screen wires " of copper wete stretched across these platinum supports inside the tube and electrical connexion was established with an automatic commutator and chronograph by means of platinum terminals on the outside of the plugs. In order to fill the tubes with the mixture required for experi-ment they were exhausted of air by means of an oil-pump half filled with the mixture and re-exhausted before being finally filled. A sample of the gas was then taken for analysis. The limits of inflammability for upward and downward propaga-tion of flame were determined in a similar tube 1.5 metres long, but without side-pieces. The gases were prepared in the usual manner the paraffin hydro-carbons being purified by repeated liquefaction and subsequent fractional distillation until on explosion of a sample with excess of air and oxygen the theoretical value for the ratio C / A was obtained. The methane used in the limit determinations in pure oxygen contained 99.8 per cent. of CH, and the ratio CIA was found to be 2-00. The oxygen was prepared by gently heating recrystal-lised potassium permanganate and contained 99.6 per cent. of 0,. The gases were stored over water rendered alkaline by potassium hydroxide and the mixtures were therefore saturated with water vapour. ESKMEALS, CUMBERLAND. [Received September 4th 1919.1 3 H"

ISSN:0368-1645    

DOI:10.1039/CT9191501436

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

1446 PAYMAN THE PROPAGATION OF FLAME IN CXXXV1.-The Propagution of Flame in Complex Gaseous Mixtures. Payt 41. The Unifomi Moceinent of Flame in Mixtures of Air with the Paq-afin Hydrocarbons. By WILLIAM PAYMAN. IN the preceding paper it was shown that all mixtures of limit mixtures are themselves limit mixtures. With each of the paraffin hydrocarbons the speed of the uniform movement of flame at the limits tends to a constant value under standard conditions of experiment. The same speed was found with all limit mixtures of methane oxygen and nitrogen and with an equimolecular mixture of methane and pentane a t its limits with air. There is no reason to doubt that the same speed would be obtained with all mixtures of the paraffin hydrocarbons a t the limits. The generalisation' advanced in the previous paper was thus shown t o apply to all such mixtures.The question immediately arises whether what is true of the speeds of flames a t the limits holds also for other speeds. Whether for example given two or more mixtures of air with different individual gases in each of which the speed of flame was the same all combinations of the mixtures would propagate flame at the same speed. Should this be so a simple method would be available for the calculation of the speed of propagation of flame in complex gaseous mixtures from the known values for the simple constituent? gases. Such a calculation could naturally only apply over the whole range of mixtures when the maximum speed of flame in mixtures of the several individual gases with air was the same; otherwise calculation would be restricted to such mixtures as possessed a speed of flame not greater than the lowest of the individual maximum speeds.It is clear, also that$ the mixtures taken for the purpose of calculation must be all of the same nature; that is t o say must all contain excess of combustible gas or must all contain excess of oxygen. The mixtures of the paraffin hydrocarbons with air seemed most, suitable t o determine whether the generalisation that applies to speeds of flames at the limits is capable of extension to the speeds of the uniform movement over the whole range of inflammable mixtures. Measurements were therefore made of the speed of the uniform movement hmixtures of air with each one of the hydrocarbons of the paraffin series up to and including pentane.The determin-ations were carried out as described in the previous paper in COMPLEX QASEOUS MIXTURES. PART 11. 1447 horizontal glass tube 2.5 cm. in diameter and 3 metres long. The results are recorded in table I. The majority of the values in column 1 for methane were obtained by Mason and Wheeler (T., 1917 111 1052). With the exception of methane the maximum speeds are approximately the same namely about 82 cm. per second. The value for methane is rather lower than this being 67 cm. per second. Owing to the few data available for the thermal constants of the paraffin hydro-carbons it is not easy to explain this difference. In each instance, the mixture having the maximum speed of flame contains more combustible gas than is required for complete combustion, The results are shown diagrammatically in Fig.1. FIG. 1. 100 80 60 40 20 1 2 3 4 5 6 7 8 9 10 11 12 13 1 Combustible gas per cent. For testing the application of the generalisation * t o speeds other than the limiting speeds the gases methane and pentane were first chosen since they were both readily obtainable in ample quantity, 'Two air mixtures were prepared one containing 7-35 per cent. of methane and the other 1.98 per cent. of pentane. In these two mixtures the speed of the uniform movement is the same about 40 cm. per second (twice the speed a t the limits) and they both contain excess of oxygen. The mixtures were then combined in varying proportions and the speeds of the uniform movement deter-mined in the usual manner.The results are recorded in table 11. * This may be termed the " speed generalisation. TABLE I. Speed of Uniform iWovement of Flame in Mixtures of Air with Horizontal Glass Tube 2.5 cm. in Diameter. Methane. Ethane. Propane, 7- F - - Per cent. of Speed cm. Per cent. of Speed cm. Per cent. of Speed cm. Per combustible. per sec. combustible. per see. combustible. per see. combustible. h 5.7 1 5.80 6.06 6-28 6.95 7-10 7.47 7-82 8-58 9.12 9.52 9.96 10.32 10.64 11.10 11.63 12-25 12.55 13.09 13.35 13.42 Ball of flame to 15 em. from spark. 23.3 26.2 28.0 35.0 37.0 42.0 47.4 58-0 64-4 66.6 66.2 65.5 63.5 57.0 47.4 35-0 30-5 22.0 19.1 Flame to 5 cm.from spark. 3-16 3.30 3.58 4.47 4.90 5.57 6.08 6-53 7.07 7.38 7.70 8.23 9.00 9.50 10.09 10-60 10.71 Flare of flame only. 18.1 26.G 52.7 65.0 80.5 82.5 85.6 81.3 75.7 60.4 45.8 27.7 23- 1 20.8 19.7 Flame to 4 cm. from spark. 2.30 2.37 2-58 2.80 3.50 4.28 4.39 4.7 1 4.84 5.14 5.90 6.58 7.10 7.30 7.35 Flame to 6 cm. from spark. 20.8 26.0 31.4 48.2 72.8 79.1 82-1 80.2 66.0 41.2 30.2 23.0 20.3 Flame to 16 em. from spark COMPLEX QASEOUS MIXTURES. PART 11. 1449 TABLE 11. Speeds of Uniform Movement of Flame in a Glass Tube 2.5 em. in Diameter with Mixtures containing 7.35 per cent. of Methane and 1-98 per cent. of Pentane respectively Mixed Together.Methane mixture. Pentane mixture. Per cent. Per cent. 75-0 25.0 50.0 50.0 25-0 75.0 21.2 78-8 - 100.0 - 100.0 Speed, cm. per sec. 39.3 39.2 39.6 39.9 39.2” 40-1 * Methane and pentane in equimolecular proportions. It will be seen that the speeds are identical within the limits of experimental error. Two mixtures containing excess of combustible gas with speeds further removed from that a t the limits were then examined in the same manner. These mixtures contained 11.00 per cent. of methane and 3-54 per cent. of pentane respectively and the speed of the uniform movement of flame in them was about 60 cm. per second three times the value a t the limits. The results are given in table 111. TABLE 111. Speeds of Uniform Movement of Flame in a Glass Tube 2.5 em.in Diameter with Mixtures containing 11-00 per cent. of Methane and 3-54 per cent. of Pentane respectively Mixed Together. Methane mixture. Pentane mixture. Per cent. Per cent. 100.0 -75.0 25-0 50.0 50-0 25.0 75-0 24-4 76-6 - 100.0 Speed, em. per sec. 59.1 59-1 60.3 59-1 59*1* 59-6 * Methane and pentane in equimolecular proportions. Once more the generalisation is found to hold with great accuracy and there is no doubt that it is true for all mixtures of the paraffins having the same speeds of flame provided that the maximum speed in mixtures of any individual paraffin with air is not too nearly approached. For if the generalisation could be supposed to apply to the ‘ I maximum-speed ” mixtures no mixture of air containing both methane and pentane should propagate th 1450 PAYMAN THE PROPAGATION OF FLAME IN uniform movement of flame a t a speed higher than the maximum speed in mixtures of methane and air.Similarly the generalisa-tion cannot apply to speeds a t the limits in mixtures of methane with atmospheres containing a high proportion of nitrogen for with such atmospheres both upper and lower limits of inflamma-bility lie a t the maximum flattened portion of the speed-per-centage curve. Bearing these limitations in mind it should be possible to calcu-late the values for the speed-percentage curve for any combination of the paraffins in air. An equimolecular mixture of methane and FIG. 2. CALCULATED VALUES:-3CsH,=+ 2Hz. . _ . ..___.... ._ ..& C5 H,2 + CH+ . . . . . .,. .... . ., . ... 3 4 5 G 7 8 9 Combustible gas per cent. pentane (which corresponds with propane) was chosen t o test the accuracy of such calculations. The results are recorded in table IV and are compared with the calculated values in Fig. 2. I n no instance was the difference between observed and calculated speeds greater than 1 cm. per second. The highest speed for which calculation was made was 60 cm. per second. It must be admitted that the gases chosen for these experiments are particularly f avourable towards the calculation since the maxi-mum speed of the uniform movement is nearly the same with each gas. As a more stringent test a mixture of pentane and hydrogen was prepared (3C,H1 + 2H2 carrespading with propam) end COMPLEX GASEOUS MIXTURES.PART 11. 1451 (a) CR4 + C6HW 7-Combustible gas. Speed, Per cent. cm. per sec. 2.55 6 cm. travel only 2.65 22.3 3.12 39.2 3.54 53.7 4-04 70.7 4-52 78-3 5.05 73.6 5.36 59.1 6-23 37-5 7-03 25.4 7-70 20.7 7.79 3 cm. travel only series of speed determinations and calculations made as before. I n this instance the maximum speeds of uniform movement in mix-tures of the individual gases with air differ widely being 82 cm. per second for pentane and 485 cm. per second for hydrogen. The results are recorded in table IV and in Fig. 2 are compared with those calculated. ( b ) 3C,H12 + 2%. /- -7 Combustible gas. Speed, Per cent. cm. per sec. 2-35 Cap only 2.47 19.7 3.02 43.3 3.56 67.7 4-03 82-7 4.48 89.5 4.91 83.7 5.77 54.0 6.25 43.6 7.10 27.9 7-80 23.1 8-60 21-5 8-72 15 cm.travel TABLE IV. The results are not in as good agreement with calculation as those obtained with the combination of methane and pentane but, even so the agreement is remarkably close considering the wide difference between the individual maximum speeds of flames. The greatest difference between observed and calculated results is only 4 cm. per second. The highest speed for which calculation was made was 60 cm. per second which is rather close to the maximum speed for pentane. It will no doubt be apparent that a limit is a t present set to the scope of the generalisation because only the speeds of flames in mixtures with air are available for purposes of calculation.When i t is remembered that the gas with the slower maximum speed of uniform movement of flame may have that maximum greatly enhanced if an atmosphere richer in oxygen than air is used it is clear that the generalisation should be capable of further extension, given the necessary experimental data. The consideration of this subject is reserved for a later paper. It now remains to deduce a method for calculating the maximum speed of the uniform movement of flame in a mixture of air with a mixture of inflammable gases and also for calculating the co 1452 PAYMAN THE PROPAGATION OF FLAME IN position of the mixture which will have this maximum speed of flame. The latter may be calculated by the method suggested in a previous communication (Payman and Wheeler this vol.p. 36), in which it was shown that if “maximum-speed” mixtures were mixed together the result would be the ‘‘ maximum-speed ” mixture for the mixed inflammable gases. For example the value for the maximum speed of uniform movement of flame for hydrogen is 38-5 per cent. for pentane 2.9 per cent. and for methane 9.9 per cent.* ‘The calculated value for the equimolecular methane-pentane mixture is 4.48 per cent. and for the pentane-hydrogen mixture (3C,HI2 + 2H,) 4.60 per cent. The value found is the same for both mixtures namely 4.55 per cent. It is interesting to note that the same value is found for propane with which these mixed inflammable gases correspond. ‘It was also suggested from a consideration of the results obtained with mixtures of air with an equimolecular mixture of methane and hydrogen that the gas for which the maximum speed of flame was the lower had the predominating effect in determining what would be the maximum speed with mixed inflammable gases.This is true for mixtures of methane and hydrogen but in general it is the gas requiring most air to attain the maximum speed of flame which is the deciding factor. This is indeed what one would expect from a consideration of the generalisation concerning the speeds in mixed gases. The larger the volume of air a combustible gas requires to produce its “ maximum-speed mixture,” the smaller is the percentage of that combustible gas in the f astest-speed mixture of air with a mixture of gases that contain it. A method for calculating approximately the maximum speed of the uniform movement of flame in mixtures of air with a mixed inflammable gas from the known values for its simple constituents, may be given from a consideration of this fact.The assumption is made that when “ maximum-speed ” mixtures are mixed together, the resulting speed is proportional to the amount of each mixture present and to the respective maximum speeds of their flames. This relationship which holds roughly for mixtures with air may be expressed as follows : aS,+bSb+cS,+ . . . . a+b+c . . . . S = 1 where S is the speed required; a b c . . . are the amounts present of each maximum-speed mixture with air; S, Sb S, . . . are the speeds of flame in those mixtures respectively. The use of the formula will be best explained by an actual * In each instance the figure given is the mean percentage over a range of mixtures having nearly the same speed COMPLEX UASEOUS MIXTURES.PART II. 1453 calculation of the maximum speed of flame for the equimolecular mixture of methane and pentane in admixture with air. The calculated value for the mixture to have the maximum speed of flame is 4.5 per cent. and this mixture will contain 2.25 per cent. each of methane and pentane. I n the maximum-speed mix-ture of pentane and air 100 parts of the mixture contain 2.9 parts of pentane and therefore 2.25 parts of pentane correspond with 2?? x 100 = 77 parts of pentane-air mixture. 2.9 Similarly 2-25 parts of methane correspond with 23 parts of methane-air mixture since the maximum-speed mixture of methane and air contains 9.9 per cent. of methane. Substituting these values in the above formula, (77 x 82) + (23 x 67) 100 s = = 78-5 cm. per second. The value found was 79 cm. per second showing an extremely close agreement. The agreement is not so good with the pentane-hydrogen mix-ture (3C,Rl2 + 2H2) the calculated value being 100 cm. per second and the speed found 90 cm. per second. The discrepancy does not appear so great however when it is remembered that there is a difference of 400 cm. per second between the maximum speeds of the flames in mixtures of pentane and air and hydrogen and air. The maximum speed of flame with mixed gases and air may also be found by a graphical method. If on a speed-percentage graph the maxima for any two gases tztken singly is joined by a straight line all the maxima for mixtures of these two gases lie approxim-ately on this line. The composition of the “maximum-speed” mixture is calculated by the method given by Payman and Wheeler (loc. cit.) and the speed then read off from the graph. ESKMEALS, CUWRERLAND. [Received October 1 Otk 19 19.

ISSN:0368-1645    

DOI:10.1039/CT9191501446

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

1464 PAYMAN THE PROPAGATION OF FLAME IN CXXXVI1.- l h e Propagation of Flame in Complex Gaseous 17Mixt w e s . Part 1II. The Uniform Movement of Flame in Mixtures of Air with Mixtares of Methane Hydrogen and Carbon Monoxide and with Indust?-ial Injlarnmable Gases. By WILLIAM PAYMAN. THE common industrial gases contain as their inflammable con-stituents methane hydrogen and carbon monoxide in various proportions. The speed of the uniform movement of flame in mixtures of methane and air in a tube 2.5 cm. in diameter was given in Part I1 of this series of papers. The speeds with hydrogen and air in a similar tube (over the major portioa of the range of inflammable mixtures) have been determined by Haward and Otagawa (T. 1916 109 83). The speeds in mixtures of carbon monoxide and air are recorded in the present paper.Mixtures of Carbon Monoxide a*nd Air.-It is well known that the rate of combustion of carbon monoxide is dependent on the amount of water vapour present. Dixon for example (Phil. Trans. 1893 184 97) has shown that the velocity of the detona-tion wave in a mixture of carbon monoxide and oxygen (2COt-0,) increases with the percentage saturation of water vapour. The present series of determinations of the speed of the uniform movement of flame in mixtures of carbon monoxide and air was carried out with mixtures saturated with water vapour a t the ordinary temperature and pressure. Since the room tempera-ture varied it was not surprising to find that the speed in a given mixture did not remain constant from day to day.Identical results were however obtained in experiments made within a few minutes of each other a t the same temperature and pressure. Table I illustrates the effect of change in the percentage saturation of water vapour on the speed of the uniform movement of flame in a mixture of carbon monoxide and air containing 50 per cent. of carbon monoxide. TABLE I . Speed of Uniform Movement of Flame in. a Mixture of Carbon Monoxide and Air (50 per cent. CO) in a Tube 2.5 cm. in Diameter . Temperature and pressure. 10" and 750 mm. ............ (1) 59.9 (2) 59-9 15" and 750 mm. ............ (1) 65.0 (2) 64-5 17' and 755 mm. ............ (1) 79.4 (2) 79-0 Cm. per sec COMPLEX GASEOUS MIXTURES. PART III. 1455 A series of determinations of speeds of flame over the whole range of inflammable mixtures was carried out during a period when the temperature of the laboratory did not alter appreciably (about 1 2 O ) .The values obtained are given in table 11. TABLE 11. Speed of Uniform Movement of Flame in Mixtures of Cu~bofi Monoxide and Air in a Tube 2.5 cm. in Iliameter at 1 2 O and 750 mm. Per cent. of carbon monoxide. 16-15 16.29 16.40 16-51 24-47 30.50 44.84 50.45 54-40 59-58 Cm. per sec. Tongue of flame only. 19.5 19.4 19.4 34.0 46-0 60-1 59.9 57.8 56.2 Per cent. of carbon monoxide. 59.81 65-55 65.84 67.10 67-57 69.00 70-63 70.68 71-19 71-31 Cm. per sec. 54.2 37.4 36.3 30-2 29.6 26-0 20.0 20.3 19.4 Trailing flame travelled 15 cm.These values are of interest in themselves apart from their con-nexion with the problem of the propagation of flame in complex gaseous mixtures inasmuch as they disclose the fact that the maximum speed of flame is obtained with mixtures containing from 45 to 50 per cent. of carbon monoxide. The mixture for complete combustion contains 29.5 per cent. carbon monoxide so that the ‘‘ displacement ” of the maximum-speed mixture is greater even than with hydrogen despite the fact t,hat the thermal conductivity of carbon monoxide is but little different from that of air. Industrial gas mixtures may contain varying proportions of water vapour. There may therefore be some uncertainty as to the correct values to use for the speed of flame in mixtures of carbon monoxide and air when attempting t o calculate the speed of flame in the mixed industrial gas.Such gases however con-tain hydrogen as well as carbon monoxide and the presence of hydrogen affects the speed of flame in a similar degree to that of water vapour. With mixtures of gases containing fairly high pro-portions of hydrogen it is therefore not unlikely that the effect of variation in the moisture content would be inappreciable. It should therefore be sufficient for our purpose to know the values for the speed of flame in mixtures of air with a mixture of hydrogen and carbon monoxide. Or the “effective” speeds for mixtures of carbon monoxide and air could be calculat.ed from such values and these speeds used for further calculation 1456 PAYMAN THE PROPAGATION OF FUME IN In this connexion it is interesting to note that Berthelot (Ann.Ckim. Phys. 1881 [v] 28 289) found the rate of detonation in mixtures of carbon monoxide and oxygen to be about half the calculated value. For mixtures of oxygen with carbon monoxide plus hydrogen the calculated values were in good agreement with those found. Similarly in the present research the maximum speed of uniform movement of flame in mixtures of carbon mon-oxide and air is found to be about half the value calculated making use of the values determined for hydrogen-air and hydrogen-carbon monoxideair mixtures. Mixtures of Hydrogen and Air.-& with tubes of smaller diameter (this vol. p. 36) it was not found possible to determine accurately the speed of the uniform movement of flame in the upper-limit mixture of hydrogen and air in a tube 2.5 cm.in diameter. A mixture containing 71.4 per cent. of hydrogen was found to be the richest which would propagate flame under the experimental conditions. The flame was not hot enough t o melt “screen wires,” but its speed as measured by means of a tapping key in connexion with a chronograph was found to be approxim-ately 50 cm. per second. A characteristic of the lower-limit mixture and of mixtures near t o it is the formation on ignition of minute balls of flame which pass steadily from the open to the closed end of the tube. These flames are propagated mainly by the influence of convection currents and the speed-percentage curve a t the lower-limit region is not continuous but shows a definite break.Nevertheless no definite distinction at the point of break in the curve could be drawn between the normal and the balls of flame the latter increasing in size and gradually changing their form as the per-centage of hydrogen increased. The speeds of the flames in mixtures near the limits are given in table 111 which completes the table given by Haward and TABLE 111. Speed of the Uniform Movement of Flame in Mixtures of Hydrogen and A i r an a Tube 2.5 cm. in Diameter. Hydrogen. Speed, Per cent. em. per see. 6.10 No flame observed. 6-19 10 6.31 12 6-52 16 14-71 120 7 1.39 50 71.51 Flame to open end only COMPLEX GASEOUS MIXTURES. PART III. 1457 Otagawa (Zoc. cit. p. 89). In only one instance was the flame hot enough to melt (( screen wires,” namely with the mixture contain-ing 14-71 per cent.of hydrogen; the remaining speeds were deter-mined by means of a tapping key. Mixtures of Methane Hydrogen and Air.-The speed of the uniform movement of flame in a tube 2.5 cm. in diameter was determined over a range of mixtures of air with two mixtures of methane and hydrogen. The first mixture contained equal volumes of methane and hydrogen (CH,+H,) the second three volumes of methane to one volume of hydrogen (3CH + H,). The results are recorded in table IV. The lower-limit flames preserved the general character of the corresponding hydrogen flames and their speeds were found to be lower than the speed in the limit mixture of methane and air. TABLE IV. Speed of the Uniform Movement of Flame in Mixtures of Air with Hydrogen Methane Mixtures in a Tube 2.5 em.in Diameter. Combustible gas. Per cent. 6-03 6.20 6.31 6-73 7.68 9-05 10.23 11.95 11-99 13-50 14-93 15.93 16.90 18.31 19.96 20.22 20.32 20.48 20.80 Speed, cm. per sec. 15.0 17.1 19.1 22.1 28.6 45-6 67.4 104.1 106.3 128.6 135.3 127.3 111.9 65.6 35.5 30.5 28.5 27.3 24-3 3CH + H2. Cornb&tible gas. Speed, Per cent. cm. per see. 6-09 18.0 6-22 19.9 6-50 21.0 6.80 27.7 7-84 39-6 9.06 58.3 9.93 78.7 11-35 84.9 12.26 82.2 13-25 66.7 14-20 45.7 14-99 27.8 15.50 22.6 The results are plotted as curves in Fig. 1 the calculated curves being shown in dotted line. The maximum speeds calculated by the method given in P a r t I1 are 150 and 99 cm.per second respectively for the mixtures CH + H and 3CH + H,. The values found were 135 and 85 cm. per second. Mixtures of Carbon Monoxide Hydrogen and Air.-Two mix-tures of carbon monoxide and hydrogen were employed of com-position CO + H2 and 3CO + H, corresponding with the methane-hydrogen mixtures. The results are given in table V and are plotted as curves in Fig. 2 PAYMAN THE PROPAGATION OF FLAME! IN FIG. 1. Combustible gas per cent. FIG. 2. ---I_ -/ __ Combustible g a s per cent COMPLEX GASEOUS MIXTUREF. PART III. 1459 From the values found for hydrogen and for the mixture 3CO+H, the speeds of the flames in midures of air with CO+H, were calculated. The results are shown in dotted line in Fig.2. The values for carbon monoxide and air were also calculated from these values and the curve is given in the diagram for comparison. It will be seen that the values calculated in this manner are much higher than those found by experiment. These '' effective " speeds have been used in subsequent calculations instead of khe values as determined which are dependent on the amount of water vapour present. TABLE V. Speed of Uniform Movement of 3'lam.e im Mixtures of Air with the Mixtures CO+H and 3CO+H i& a Tube 2.5 cm. in Diameter. CO + H,. Combustible gas. Per cent. 9-25 10.35 15-40 20.57 30.25 36.94 41.50 45-92 51-23 58.55 69.00 70.75 71.34 Speed, cm. per sec. 18.2 21.1 58.3 100.4 211.5 282.9 309.7 315.2 280.0 178.5 64-5 50-1 44.4 3CO + H,.Comb;stible gas. Per cent. 12.00 18.99 27.82 34-73 41.32 46.90 53-17 58-49 70.36 71.42 -. Speed, cm. per see. 19.2 67- l. 115.0 166-2 205-5 214.0 200.0 154.7 3 4 4 20.8 Mixtures of Methane and Carbon Monoxide and Mixtures of Methane Hydrogen and Carbon Monoxide with Air.-Table VL records the results obtained with a mixture containing equal volumes of methane and carbon monoxide and with one containing equal volumes of methane hydrogen and carbon monoxide. Methane or any gas into the composition of which hydrogen enters, acts towards mixtures of carbon monoxide and air in a manner comparable with that of hydrogen and water vapour. The maxi-mum speed of uniform movement of flame in mixtures of air with each of the mixtures CH + CO and CH + CO + H was found to be 91 and 150 cm.per second respectively whilst the correspond-ing calculated values are 78 and 145 cm. per second 1460 PAYMAN THE PROPAGATION OF FLAME IN CH + CO. c - Combustible gas. Speed, TABLE VI. Speed of Uniform Movement of Flame in Mixtures of Air with the Mixtures CH + CO and CH + H2+ CO in a Tube 2.5 cm. in Diameter. CH + H + CO. I . Combustible gas. Speed, 9.45 9.88 12.07 13.73 15-95 18.06 19.32 21.55 cm. per sec. 21-9 36.2 62-5 85-7 91.3 68.9 52.3 19.8 FIQ. 3. I I 5 10 20 30 7.70 10.01 14.01 15.80 18-92 20.42 22-43 25.05 27.57 21.2 36.5 83-3 109.4 150.0 148.7 118-5 57.8 21.8 60 70 1 50 Combustible gas per cent.The speed-percentage curves for the equimolecular mixtures CH,+H2 H,+CO CO+CH, and CH,+H,+CO are plotted in Fig. 3 the curves for the pure gases being included for comparison. Mixtures of Industrial Gases with Air.-The equimolecular mix-ture of carbon monoxide and hydrogen correspond nearly with A coal-gas and a producer-gas were also examined, the compositions of these being : water-gas. COMPLEX GASEOUS MIXTURES. PART 111. 1461 Coal-gas. Producer-gas. Per cent. Per cent. - Benzene and higher olefines ......... 1.1 Carbon dioxide 0.3 5-0 Ethylene ................................. 2.6 Carbon monoxide ........................ 9.6 21.3 Hydrogen ................................. 49-2 12.6 Methane and higher paraffins ......33.9 3.1 Nitrogen (by difference) ............... 3.3 58.0 ........................... -The speeds of the uniform movement of flame in mixtures of air with each of these two gases are given in table VII. TABLE VII. Speed of Uniform Movement of Flame in Mixtures of Air with Coal-gas and with Producer-gns in a Tube 2.5 cm. in Diameter. Coal-gas. Per cent. 7.2 10-0 11.9 14.7 16.8 17.9 20-4 21.8 24.3 Speed, cm. per sec. 21.5 50.5 87.1 133.7 153.9 154.1 115-6 74.3 22-0 Producer-gas. Per cent. 24.7 38.9 46-0 49-0 54.3 58.8 61.6 Speed, cm. per sec. 20.0 47.4 62.7 72.2 69.7 43.5 24.0 The principal constituents of the coal-gas are hydrogen methane, and carbon monoxide.I f all the hydrocarbons be reckoned as methane the calculated maximum speed of uniform movement of flame in mixtures of air with this coal-gas is 164 cm. per second, with a mixture containing 18.4 per cent. of coal-gas. Since the content of inert gases (nitrogen and carbon dioxide) is low they may be neglected when making the calculations. Producer-gas on the other hand always contains a large pro-portion of inert gas; the sample used for these experiments con-tained only 37 per cent. of combustible gas. For this reason a value for the maximum speed of uniform movement of flame in a mixture of producer-gas and air calculated from the maximum speeds in mixtures of the pure gases with air would be too high. The speed of flame in mixtures of air with gas containing a large proportion of nitrogen can be calculated on the assumption that the cooling or retarding effect on the flame of excess of air or of nitrogen will be the same since their specific heats are the same.* A mixture of carbon monoxide hydrogen and methane in the pro-* This assumption is not quite correct since the presence of reactive gas slightly opposes the retarding effect of air 1462 WHITE AND PRICE THE IGNITION OF portions in which they are found in the sample of producer-gas used in these experiments will have as its “ fastest-speed ” mixture with air one containing 34.7 per cent.of combustible gases. I f nitrogen is added to this mixture so that the ratio of nitrogen to combustible gases is the same as in the producer-gas the result is a mixture containing 21.7 per cent. of combustible gases. (The carbon dioxide content being low it may be calculated as nitrogen.) The speed of flame in this mixture should on the assumption given above be but little different from the speed of flame in the same mixture of combustible gases with air. The latter speed is most easily determined by a graphical method and is found to be 85 cm. per second. The mixture of air and producer-gas with the fastest speed of uniform movement of flame contains slightly more inflammable gases than is required for complete combustion. A greater “dis-placement ” of the maximum-speed mixture might be expected for the reason that the chief inflammable constituents are hydrogen and carbon monoxide the individual displacements of which are con-siderable. The small displacement with producer-gas is due to the presence of inert gases as will be explained in the succeeding section of this series of researches. The effect in general of inert gases on the speed of the uniform movement of flame in gaseous mixtures will also be considered. ESKMEALS, CUMBERLAND. [Received October loth 1919.

ISSN:0368-1645    

DOI:10.1039/CT9191501454

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

1462 WHITE AND PRICE THE IGNITION OF CXXXVIH1.-The Ignition of Ether-Alcohol-Air and Acetone-A ir Mixtugm in Contact with IJeated Surfaces. By ALBERT GREVILLE WHITE and TUDOR WILLIAMS PRICE. OWING to the large number of fires which had occurred during 1917 and 1918 in solvent-recovery stoves in which cordite was being dried it was decided t o investigate the conditions under which mixtures of the vapours of ether alcohol and acetone with air would ignite. This was rendered all the more necessary by the fact that the information available on this subject was scanty and often contradictory. As a general rule the actual rise in temperature necessary to cause the explosion of such an explosive as glyceryl trinitrate is much lower than that needed to ignite an explosive gaseous mix ETHER-ALCOHOL-AIR AND ACETONE-AIR MIXTURES ETC.1463 ture. On the other hand the lower thermal capacity of the gas and its comparatively far greater mobility render it more susceptible to ignition in many cases. There was thus some justifi-cation for the idea that the solvent-air mixture was probably responsible for many of the recovery-stove fires that had occurred, particularly when it is remembered that fires had been less fre-quent in “final” stoves than in recovery-stoves that more fires had occurred with cordite from which a mixture of ether and alcohol was being removed than when the solvent was acetone and that ether when mixed with air is indubitably more dangerous than acetone under similar conditions. The factors affecting the ignition of a combustible gaseous mix-ture are many and the influence of some of them is not particu-larly well understood.The problem of safety when dealing with such a mixture under manufacturing conditions divides itself naturally. into two parts the one dealing with the ignition of the mixture and the other with the propagation of the flame from one portion of the mixture to another for example from one build-ing to another. This division is seen to be inherent when it is remembered that by using a sufficiently powerful source of ignition it is possible to ignite almost any combustible gas-air mixture whereas the propagation of the flame is a totally different matter particularly if the gas-mixture considered is at rest. I n such a case there appear to be definite limits for the proportion of combustible gas to air in a mixture which propagates flame, these limits depending ultimately only on the direction of pro-pagatibn and the nature of the combustible gas used a t ordinary temperature and pressure.The experimental work is accordingly divided into three sections : (1) The ignition-temperatures of various gas-mixtures including ether-air alcohol-air and acetone-air mixtures. (2) The limits for the propagation of flame in these mixtures. (3) The investigation of a few miscellaneous facts concerned more particularly with various means of ignition. The fact has not been lost sight of that ease of ignition and propagation of flame might be enhanced by the presence of some impurity in the solvent vapour-air mixture.Accordingly experi-ments have been carried out to ascertain the effect of adding slight amounts of glyceryl trinitrate and of the peroxides of ether to the gas-mixtures dealt with. This was the. more necessary as glyceryl trinitrate even though present in the stove vapours in minute quantities is known to be a source of possible danger and also because there appears to be a tendency to assign any otherwise inexplicable explosion or fire wit,h ether t o the influence of thes 1464 WHI!CE AND PRICE THE IGNITION OF peroxides (compare Neander Chem. Zeit. 1902 26 336 and others). This idea seems to have arisen chiefly from the fact that ether which had given trouble had generally been kept for some time and also because it was well known that the exposure of purified ether to light caused the formation of compounds which appeared t o contain active oxygen.The methods used to prepare these compounds were those given by Baeyer and Villiger (Ber., 1900 33 3387; 1901 34 738). Naturally great care was exercised in freeing the solvents used from such impurities. The ether used was twice distilled from acid permanganate and washed several times first with a concentrated solution of potassium hydroxide in water and then with a dilute one. It was then washed several times with distilled water dried distilled and again dried for several days over sodium. On fractionating twice with a Young and Thomas still-head a fraction boiling within 0.05O of the boiling point of the pure substance was colleFted each time. The alcohol used was ordinary absolute alcohol which was twice heated under reflux for four hours over fresh lime then twice over calcium turnings for two hours and refractionated as for ether the fraction collected boiling within 0.05O of 78*4O.The acetone was purified by converting it into the sodium iodide compound collecting and distilling the double compound. The product was then carefully dried and fractionated twice as in the case of the other compounds. The purity of the solvents used can be gauged from the fact that the acetone obtained had D,"0.7808, as low a figure as any published. These solvents were carefully preserved in a dark cupboard. Except when otherwise specified percentages can be taken to mean percentage by volume. Tubes are also often specified by their diameters.Thus a tube 5 cm. in diameter would be referred to as a 5 cm. tube. SECTION I. The Zgnition- t emperatures of Et her-A Icohol-A ir and Acetone-Air Mixtures. With the exception of two figures for ether in air 1033O given by McDavid (T. 1917 111 1003) and 190° by Alilaire (Compt. rend. 1919 168 729) the ignition-temperatures found in the literature for the solvents in question are spontaneous ignition-temperatures which can be taken to be the temperatures a t which the substances dealt with (surrounded by oxygen or air a t the same temperature) will burst into flame without the application of any spark or other local high temperature. Two sets of these figures, which are intended for engine work are given. Thus Hol ETHER-ALCOHOL-AIR AND ACETONE-AIR MIXTURES ETC.1465 (Zeitsch. angew. Chem. 1913 26 i 273) gives the spontaneous ignition-temperature of alcohol in air as 510° of acetone as 570°, and of ether as 400O. Moore ( J . SOC. Chem. Imd.,. 1917 36, 109) gives the spontaneous ignition-temperatures of ether and alcohol in air as 347O and 51B0 and in oxygen as 190° and 395O respectively. It will be seen that only the figure given for the ignition-temperature of ether in air by Alilaire which was pub-lished after the completion of our work appears to be sufficiently low t o make an ignition of the solvent-air mixture under presenb clay conditions of recovery seem feasible. A paper by Perkin (T. 1882 41 363) on the luminous incom-plete combustion of ether is interesting in this connexion. Accord-ing to him this phenomenon was first discovered by Davy who noticed a pale phosphorescent light round a hot platinum wire.Doebereiner noticed the same thing and also remarked that when ether was dropped into a retort heated on the sand-bath to looo and upwards or into a platinum capsule exposed to the vapour of boiling water the spheroidal state is produced accompanied by a blue flame visible only in the dark and not capable of setting fire to other substances lachrymatory vapours of lampic acid being formed . Boutigny and Miller also noted this flame ‘and the products of the combustion and proved that metal or porcelain dishes were equally effective in producing these phenomena. Boutigny gives the temperature a t which ether begins to burn with this flame as a little below that of fusing lead and so agrees with Perkin and others that the temperature necessary must be about 260°.As will be seen later however a temperature much below this is sufficient to produce this flame in ether-air mixtures. According to Perkin this blue flame has a comparatively low temperature (it has since been designated a ‘(cool” flame). The fingers may be placed in it with impunity. It will neither char paper nor ignite carbon disulphide and a lucifer match may be held in it for some time before being ignited. He also states however that ether vapour burning with this blue flame when in large quantities or more especially in a confined space rapidly increases in tempera-ture and quickly enters into ordinary combustion. Perkin also examined other substances for (( the luminous appear-ance accompanying incomplete combustion .” Only traces of blue flame were obtained with the alcohols up to amyl methyl alcohol giving none.The generally accepted definition of ignition-temperature is that temperature to which a gas-mixture must be heated a t least locally, for the speed of the reaction to be such as to become self-suppor 1466 WHITE AND PRICE THE IGNITION OF ing. This temperature is not that at which a flame appears but that a t which self-heating becomes sufficient to cause ultimate inflammation. That the determination of an ignition-temperature is a matter of great difficulty can a t once be seen when it is considered that the temperature a t which such a reaction would become self-sup-porting must depend on the rate of dissipation of heat in the system as well as on many other factors.For instance if the time taken to bring the gas-mixture up to the ignition-temperature is appreciable the composition of the gas-mixture alters and i f a solid is in contact with the heated gases even below their ignition-temperature as proved by Bone and Wheeler (Phil. Trans. 1906, [ A ] 206 I) and by Meyer and Preyer (Ber. 1892 25 622) the most divergent results are obtained for the amount of combination that takes place. From their work the German investigators concluded that it was impossible to determine an ignition-temperature. We decided to try the soap-bubble method described by McDavid (Zoc. c i t . ) and if that proved unsatisfactory as was anticipated from Meunier’s work (Conzpt.rend. 1907-1912) to attempt to make use of a method in which the amount of heated surface brought into contact with the gas would be known thereby elimin-ating the most obvious defect in the soap-bubble method as pub-lished. To this end it was decided to pass the various gas-mixtures of which the ignition-temperatures were required into certain uniformly heated vessels. I n this way the temperature a t which ignition could be obtained in each vessel would be known. By taking vessels of the same material having different ratios of surf ace to volume and plotting the ignition-temperature against surface per unit volume it was anticipated that by ext.rapolation it would be possible to eliminate to a great extent disturbing variations due to surface action.The most obvious vessels to use were tubes of various diameters and a series of these was accord-ingly chosen. It was quite realised that the longer time taken to heat a large bulk of gas would affect the results t o some extent but direct experiment in which some of the products of combustion were introduced into the gas-mixture to be used soon proved this to be almost negligible in the case of ether-air mixtures of ordinary concentration. It is to be noticed however that in this method the temperature determined has been called the sub-ignition-temperature-the minimum temperature a t which combination in a gas-mixture becomes self-supporting. This appears t o be the practical temperature required as the phenomenon obtained may or may not give rise to ordinary combustion depending on circum ETHER-ALCOHOGAIR AND ACETONE-AIR MIXTURES ETC.1467 stances. Its identity with the ignition-temperature of a mixture depends entirely on what is understood by “ignition,” and a “flame ” in those cases in which cool flames are possible phenomena. Heating a gas-mixture quickly to its ignition-temperature is always assumed t o cause ultimate inflammation. In many cases, an ordinary flame causing more or less complete combustion cannot be obtained by heating a gas to its sub-ignition-temperature and in those cases in which such a flame appears it is only produced through the cool^' flame of incomplete combustion. For a fairly concentrated ether-air mixture the cool flame obtained is very similar in appearance to an ordinary flame but for very dilute mixtures it becomes practically a travelling phosphorescent flow.The Soap-bubble Method.-The results obtained during our investigation of the soap-bubble method of determining ignition-temperatures have already been published (this vol. p. 1248). By using different; igniting surfaces it was found that the ignition-temperature of a 5 per cent. ether-air mixture as determined by this method could vary from 907O to 1064” whilst that of a 12 per cent. mixture could vary from 870° to 1035O. The results obtained seemed to be erroneous and by using several gas-mixtures it was shown that the method could scarcely be trusted even for com-parative results. The Exhausted Tube Method.-The apparatus used in this method is shown in Fig.1. The heated vessel consisted of a long glass tube sealed a t one end and closed at the other by means of a rubber stopper. The tube could be kept a t any desired tempera-ture by means of an electric furnace the exact temperature inside the tube being registered by means of a copper-constantan couple except when that temperature was more than 500* when a nitrogen-filled mercury thermometer was used. The ignition tube was connected to the glass reservoir containing the mixture under examination by means of a glass lead passing through the rubber stopper. A three-way tap was inserted between the tube and reservoir in such a manner that the tube and lead could be con-nected a t will to the reservoir or to a Gaede box pump. The reservoirs were of 15 to 17 litres capacity and the tubes used a t first were a few cm.longer than the furnace which was 50 cm. long. The reservoir was filled with any required mixture by exhausting it and allowing air to sweep a known weight of the solvent from the filler shown in the figure. The filler was con-nected to the three-way cock by means of rubber tubing but the end of the filler always projected into the tap tube. In this way, none of the solvent escaped introduction into the reservoir and a knowledge of the molecular weight of the solvent together with VOL. uxv. 3 1468 WHITE AND PRICE THE IGNITION OF the temperature and pressure gave by means of a simple calcula-tion the percentage volume occupied by the solvent in the reservoir. A portion of the lead between the three-way tap and the furnace was connected to the remainder by means of rubber joints.These joints enabled tubes of various internal diameters to be introduced in order to vary the rate a t which equalisation of pressure in the tube and reservoir took place. An experiment was conducted as follows. The tube was exhausted to a pressure below 2 cm. and connected t o the reservoir by turning the three-way cock as rapidly as possible; an observer looking through the FIG. 1. c: Mt4L f Yo& T n CTCR sealed end of the tube (shielded by a plate of glass) reported whether ignition had or had not taken place. Shock Zgnition.-Preliminary experiments using 5 to 15 per cent. mixtures of ether in air and a tube 2 cm. in diameter gave results varying with the diameter of lead used.It was also found that changing the length of the tube from 50 to 100 cm. affected the temperature a t which ignition was obt.ained. These irregulari-ties were presumably due t o the differences in time taken to fill the tube with the gas-mixture. Accordingly a tube 7.5 cm. in diameter was substituted for the one previously used so that the effect of changing the diameter of the lead could be investigated more easily. With a lead of 1 mm. diameter ignition took plac ETHER-ALOOHOGAIR AND AUETONE-AIR MIXTURES ETC. 1469 a t temperatures near 200° but on using a lead of 5 mm. in diameter it was found possible to obtain ignition at from 50° to 60°. These resullx were obviously too low and observation showed that they were influenced by the position of the end of the tube relative to the furnace.Experiments were carried out to elucidate this phenomenon and it was found possible to ignite ether-air mixtures a t the ordinary temperature and to ignite other gaseous mixtures a t temperatures well below those commonly considered as their ignition-temperatures. The apparatus used consisted of a glass tube 7.5 crn. in diameter which was connected to a reservoir of 16 litres capacity by means of a glass lead 80 cm. long and of 1.9 cm. internal diameter. By using on the reservoir a cock of 1.5 cm. bore it was possible to equalise the pressure in the two portions of the apparatus very suddenly. Under these conditions, it was found that when the tube and lead were exhausted and kept a t the same temperature as the reservoir (16*5O) ether-air mixtures containing 5 t.0 15 per cent.of ether were ignited on opening the reservoir cock. The ignition invariably took place within 15 cm. of that end of the tube remote from the reservoir. In most cases it resulted in a pale blue flame which travelled quietly along the tube but sometimes gave inflammation sufficiently violent to shatter the glass. When using 7.5 cm. tubing ignition could be obtained easily with 60 and 90 cm. lengths even when the pressure in the reservoir was less than half the atmospheric. Ignition occurred in a 150 cm. tube only when the pressure in the reservoir was greater than three-quarters of an atmosphere. When a 300 cm. tube was used no ignition could be obtained at the ordinary temperature ; a similar negative result was obtained with bottles 30 cm.long and 11.2 to 12.5 cm. in diameter that is of approxim-ately the same capacity as the 90 cm. h b e . A pad of soft leather in the closed end of a tube of optimum length seemed t o prevent ignition a t the ordinary temperature and a plug of cotton wool prevented ignition in precisely the same way. Replacement of the 7.5 em. tube by one 2 cm. in diameter brought about the same result. It appeared to be immaterial whether highly purified ether or the ordinary commercial variety was used for these experi-ments. Amongst the other gases tested were mixtures of hydrogen and the vapours of acetone and carbon disulphide with air. Dilute carbon disulphide-air mixtures ignited a t the ordinary temperature acetone-air mixtures below 250° and hydrogen-air mixtures below 450° but these experiments were not continued.The information a t present available makes it appear highly prob able that this ignition is due to the shock caused by the sudden 3 1 1470 WHITE AND PRICE THE IGNITION OW stoppage of the gas rushing into the exhausted tube. In this con-nexion a statement made by Sir Charles Parsons in his inaugural address a t the Bournemouth Meeting of the British Association (1919) is of interest. This was to the effect that during the work of a committee appointed by the Admiralty in 1916 to investigate the cauge of abnormal propeller erosion it was discovered that by allowing water to rush into an exhausted conical vessel a pressure of more than 220 kiloa.per sq. mm. was recorded a t the apex of the cone. That ignition of a gas-mixture can be produced by a compression wave was demonstrated by Bradshaw (Proc. Roy. SOC., 1907 [ A ] 79 236) for mixtures of carbon disulphide in oxygen and for electrolytic gas. Another factor the actual rarefaction must not be forgotten. Investigations by Mitscherlich (Ber. 1893 26 399) on the temperature necessary to explode mixtures of hydrogen and oxygen seem to show that the explosion point is reduced very appreciably by lowering the pressure. Again Labillardiere Friedel and Ladenburg Stock and Guttmann and others have shown that the temperature necessary for the ignition of mixtures of the hydrogen compounds of phosphorus silicon and antimony with oxygen is presumably lowered by reducing the pressure and that explosion has been known to follow sudden rarefaction.In the cour8e of the work described in this paper the maximum reduction in sub-ignition-temperature of ether-air mixtures apparently obtained by reduction in pressure alone was only 7O that is from,187° to 180° as shown in Fig. 4. This appears to leave a fair margin for other factors. The importance of this “shock ’’ ignition is obvious whether it be considered from the theoretical or practical point of view and it may quite well account for hitherto obscure ignitions met with in the course of solvent-recovery and mine work. The phenomenon underlying shock-ignition must also invalidate a good deal of research work. A t t empt to E Zimina t e Sh ock-ignition .-One conceivable method of avoiding shock-ignition in the determination of sub-ignition-temperatures would appear t o be that in which the gas is given no appreciable flow before being stopped.An attempt t o realise these conditions was made by joining a small bulb on to a gas reservoir in such a way that the distance between the bulb and reservoir was as small as possible. A three-way tap was inserted between the reservoir and bulb to enable the bulb to be exhausted before an experiment. The bulb which was m‘ade of glass was kept a t any desired temperature by being almost entirely immersed in a bath of mercury. When once a connexion had been mad ETHER-ALCOHOL-AIR AND ACETONE-AIR MIXTURES ETU. 147 1 between the bulb and gas reservoir the tap was turned so as to close both bulb and reservoir.I f ignition took place a flash was easily observed where the bulb-stem emerged from the bath. The bore of the bulb-stern was varied in different determinations. The results obtained when using a 4.5 per cent. mixture of ether in air are given in table I. From them it will be noticed that the effect of the size of lead is not completely eliminated by this method. TABLE I. Showing the Subignition-temperatures of a 4.5 per cent. Ether-Air Mixture obtained by the Bulb Method using Various Leads. Sub-ignition-temperature when ,lead was L Diameter r- . of bulb in cm. Ordinary tube. Capillary. Fine capillary. 4.8 178.0" 181.0" 184.0" 4.1 179.0 184.0 186.0 3.5 180.5 185.5 188.0 An interesting point observed in these experiments was the fact that when using a 4.5 per cent.mixture near its apparent ignition-temperature explosion invariably occurred. On the other hand, when using the bulbs specified above with an ordinary capillary lead and the same gas-mixture on no occasion did an explosion take place when the temperature of the bath was greater than 1 9 7 O . Above this temperature a luminous flash was observed and nothing more. A 6 per cent. mixture gave simiIar results but a 10 per cent mixture gave no explosion a t any temperature tried. An 8 per cent. mixture behaved in precisely the same way as a 10 per cent. mixture except that on one solitary occasion a violent explosion shattered the bulb. It is possible that a good approxim-ation to the correct sub-ignition-temperature could be obtained by using a very fine capillary tube and a fairly large bulb but the experiment would not be without danger.Final Apparatus.-It was found that by making use of a fairly long tube and allowing the sealed end to project well out of the furnace effects of shock-ignition were apparently eliminated. I n this case the point a t which shock-ignition would have occurred in normal circumstances was well outside the heated zone and on no one occasion was an ignition in the final apparatus observed to start outside the furnace. The lengths of tube used were as follows: 2 cm. tube. 100 cm. 4 cm. tube. 130 cm. 6.6 cm. tube. 130 cm. The chief difficulty encountered was that of deciding when an This was generally easy in the case of ignition had occurred 1472 WHITE AND PRICE THE IGNITION OF shock-ignition as not only was the flame fairly easily seen but the products of combustion had a characteristic and powerful odour.In the case of dilute mixtures of ether in air and ether-alcohol-air mixtures containing small quantities of ether however the matter was quite otherwise. It was found almost impossible to distinguish between an ignition and the glow given below the sub-ignition-temperature by combustion on the surface of the glass until travel-ling was taken as the criterion. This was of course due to the fact that the ignition a t the lowest possible temperature of a mix-ture containing ether and air invariably commenced with what has been termed the cool flame. This flame often requires a completely darkened room in order to be visible but whenever any appreciable quantity of combustible mixture is present it is liable t o develop more or less rapidly into ordinary combustion and possibly, detonation.That the volume of mixture present is an important factor can be seen from the fact that on no occasion did ordinary combustion develop in the 2 cm. tube within 150° of the sub-ignition-temperature. On the other hand when using mixtures containing from 5 to 10 per cent. of ether in either of the other tubes ordinary combustion was liable to develop and certainly did develop if the temperature was a few degrees above that necessary for inflammation. Test experiments carried out with and without the thermo-couple and thermometer in the tube showed that the presence of these instruments did not appear to affect the result obtained.Fig. 2 gives the results obtained for the sub-ignition-temperatures of various ether-air mixtures. It will be noticed that in the case of the 2 cm. tube the results for dilute mixtures differ slightly according to the lead used. This is presumably due to the fact that combustion takes place to a relatively greater extent in the case of the smaller lead making i t more difficult to see the flame a t the same temperature. On the other hand above a certain limit the internal diameter of the lead does not appear to affect the results obtained with the other tubes. Surface action appears to be negligible in the case of ether-air mixtures of any appreciable concentration if the tube has a diameter of a t least 4 cm.That the longer time taken t o heat the larger bulk in a wide tube made little difference in the case of ether-air mixtures of concentration greater than about 4 per cent. was proved by adding 1.5 per cent. of the products of combustion of an ether-air mixture to a 5 per cent. mixture of ether in air. The sub-ignition-temperature was only raised 2O. It was found that no difference in sub-ignition-temperature could be detected when purified ether was replaced by the commercial article. It is interesting to note from the shap ETRER-ALCOHOL-AIR AND ACETONE-AIR MIXTURES ETU. I 473 of the curve in Fig. 2 that the ignition of ether-air mixtures by this method depending as it does on the preliminary production of the cool flame appears to be a molecular process requiring only a certain intensity of molecular movement for its production.The form of curve connecting minimum igniting current with composi-tion of ether-air mixture appears to be quite different. I n Fig. 3 can be seen the sub-ignition-temperatures of certain ether-alcohol-air mixtures as determined in the 2 cm. and 4 cm. FIG. 2. x Percentage of ether in mixture. A. 2 cm. tube 1 and 3 mm. leads. B. 4 cm. tube 3 mm. lead. C . 5& cm. tube 3 mm. lead. tubes. 'The number of points shown on each curve is not great, owing to the fact that the general form of the curves had been previously found when using smaller leads. Each point on the diagram is the mean of three determinations agreeing t o within 20 in the case of temperatures below 220° and to within 5 O in the case of temperatures above this point.A consideration of the results given shows that the sub-ignition-temperature of an ether-alcohol-air mixture falls very rapidly when the amount of ether in the mixture is increased from 1 to 1474 WHITE AND PBICE THE IGNITION OF per cent. This drop is seen to take place with a smaller per-centage of ether in the case of the 4 cm. tube and in both tubes with a smaner percentage of ether in the case of the mixture con-taining the smaller amount of alcohol. The curves also indicate the manner in which the addition of alcohol to an ether-air mix-ture affects the sub-ignition-temperature. The elevation in sub-ignition-temperatures is roughly proportional to the amount of alcohol present provided the ether-content lies between 2 and 5 per FrG.3. 480" 180 Percentage of ether in mixture. cent. tubes are given in t.able.11. For comparison some results obtained with 4 and 5.5 em. TABLE 11. Showing the Sub -ignition- t enzperatures of Various E t her-A lcohol-Air Miztures containing 2 per cent. of Alcohol as determined in 4 and 5.5 em. Tubes. Sub-ignition-temperature for > Percentage of 5-5 cm. tube. ether in - 4 cm. tube, mixture. 5 mm. lead. 3 mm. lead. 3 mm. lead. 1 495" 500" 470' 2 220 222 217 3 207 210 203 t 201 205 19 ETHER-ALCOHOGAIR AND ACE)TONEI-AfR MIXTURES ETC. 1476 is 4 The sub-ignition-temperature determined with the 5.5 cm. tube seen to be higher in every case than that obtained with the cm. tube. This is probably due t o the fact that owing to the larger diameter of this tube the time of heating is necessarily longer and hence slow combustion occurs more readily.With this tube too a slight but perceptible difference in sub-ignition-temperature is obtained when using 3 mm. and 5 111111. leads as shown in table 11. It was seen that in the case of dilute mixtures of ether in air the size of lead used if small affected the temperature obtained. This effect was exceedingly marked in the case of ether-alcohol-air mixtures containing little ether. With small leads it was found impossible to obtain consistedt results. For instance for a mix-ture of 2 per cent. of alcohol and 1-25 per cent. of ether in air, when using a 1 mm. lead with the 4 cm. tube a flash would occasionally be obtained below 300° but one could only be certain of an ignition well above 400O.It was found however that if the cock connecting the tube and reservoir was turned on slowly, no ignition was ever obtained below 400". These differences vanished when leads of 3 mm. or more were used. The sub-ignition-temperatures of various alcohol-air mixtures are given in table 111. TABLE 111. Showilzg the Szct,-igrtition-temperatzlres of Vapiozcs A tcohol-Air Mixtures as determined in 2 em. 4 em. and 5.5 ern. Tubea. Sub-ignition-temperature for Percentage of F A I aloohol in 2 crn. tube 4 cm. tube 54 cm. tube mixture. (3 mm. lead). (3 mrn. lead). (6 nun. lead). 2 515" 500" 620" 3 505 490 605 4 486 470 600 6 480 465 496 I n the 4 cm. tube an explosion was often obtained with 4 and ij per cent.alcohol-air mixtures a t 485O. The evidence as to the slower heating of the gaseous mixture in the largest tube is con-firmed by the figures given here as the temperatures found in the case of the largest tube are higher than those for the smallest,: It thus appears from the above figures that the nearest possible approach to the correct sub-ignition-temperature of an ether-alcohol-air mixture is obtained by means of a 4 cm. tube. Itq was found that almost identical results were obtained in the 2 cm. and 4 cm. tubes whether 2 or 3 mrn. leads were used and that it was not important whether a 3 or 5 mm. lead was used for the 3 I 1476 WHITE AND PRIUE THE IUNITION OF 5.5 cm. tube. The sub-ignition-temperatures considered most likely to be correct are summarised in table IV.TABLE IV. Showa7tg the Sub-ignitiomtemperatures of Various Ether-Alcohol-Air Mixtures. Percentage composition of mixture by volume. c -Ether. 3-16 8 4 3 2 1 8 4 3 2 1 0 0 0 0 Alcohol. 0 2 2 2 2 2 4 4 4 4 4 2 3 4 5 3 Air. 97-86 90 94 95 96 97 88 92 93 94 95 98 97 96 95 Sub-ignition-temperatures. 187' 189 198 203 217 470 194 200 220 255 465 600 490 470 465 The sub-ignition-temperatures of some acetone-air mixtures as determined in tubes of various diameters were found to vary in a manner similar to those of alcohol-air mixtures. The results given below were obtained when using a tube 4 cm.in diameter with a 3 mm. lead. TABLE V. Showing the Sub-ignition-Temperatures obtained for some A c e t one-A ir Mix t ur es . Percentage of acetone Sub-igni tion-in acetone-air mixture. temperature. 4 500" 8 500 Saturated at 15" 505 The ignition found for acetone was very faint a t the sub-ignition-temperature but grew in intensity very rapidly as the temperature of the tube increased. ZnfZuence of Pressure .-During the course of preliminary work on the determination of sub-ignition-temperatures of ether-air mixtures it was found that consistent results were not obtained for successive experiments when the mixture in the reservoir was not renewed after each determination. This was apparently due to change of pressure inside the reservoir.Several experiment ETHER-ALCOHOL-AIR AND AOETONE-AIR MIXTURES ETC. I477 were therefore made in which the pressure in the reservoir was reduced by pumping out the gas-mixture before firing and it was found that when the pressure in the reservoir after an experiment was plotted against the sub-ignition-temperature determined the curves shown in Fig. 4 were obtained. Other mixtures tested in the same way gave precisely similar resulk and it was finally found FIG. 4. 190 180 Pressure in cm. that the easiest method of determining the accurate sub-ignition-temperature of any given mixture under 760 mm. pressure was by starting with a gas-mixture under about 900 mm. pressure and plotting a small portion of the pressure-sub-ignition-temperature curve.It will be observed that the minimum sub-ignition-temperature The results given in Fig. 2 were obtained in this way. 3 J" 1478 WHITE AND PRIOB! TBE IGNITION OB’ appears to be given a t a lower pressure in the cam of a mixture rich in ether than in the case of a dilute mixture. This is prob-ably due to the fact that there is a minimum quantity of ether per unit volume necessary to give visible luminosity under any given conditions. In@aence of the Material of tlte Tube.-A consideration of the results obtained with various tubes shows that it was impossible to eliminate surface action entirely probably owing to the fact that in the case of the larger tube the heating of a body of gas is necessarily slower. It thus became a matter of importance to dis-cover whether the material of the tube had any influence on the result obtained.The simplest method of effecting this appeared to be by fitting a glass tube with a thin sleeve of the material under test. Accordingly the 4 cm. tube was fitted with sleeves long ,enough to project beyond the furnace on either side these sleeves being made of various metals that might conceivably be used in a manufacturing plant in the presence of gas-mixtures such as those considered. The results obtained are giSen in table VI. TABLE VI. Showing the Results obtained f o r the Sub-ignition-temperature of Ether-Air and Alcohol-Air Mixtures in a 4 cm. Tube provided with an Internal Metallic Sleeve. Sub -ignition-temperature. Material of 4.3 per cent. sleeve. of ether in air.Glase ........................... 187’ Copper ........................ 175 Iron ........................... 178 Lead ........................... 180 Zinc ........................... 184 Galvanised iron ............ 184 10.5 per cent. 5 per cent. of ether in air. of alcohol in air. 187O 466O 176 420 178 400 180 -184 e 184 -The figures given for copper and iron in the case of the alcohol-air mixture can only be regarded as rough approximations owing to the rapidity with which these metals oxidised at the tempera-ture necessary for ignition. When the metal was oxidised to any appreciable extent different results were obtained. For instance, the sub-ignition-temperature in the case of a copper sleeve oxidised in the course of ten experiments was 4 7 0 O .In the case of both ether-air and alcohol-air mixtures the ignition commenced as a cool flame but was invariably more violent in the presence of metals more particularly copper and iron than with glass. Influeme of the Velocity of t h e Gas-mixtu~e,-As the gases dealt with in solvent-recovery are generally in motion it wa ETHER-ALCOEOL-AIR AND AOETONE-AIR MIXTURES ETC. 1479 decided to investigate to some slight extent the effect of the velocity factor on the sub-ignition-temperatures obtained. Arrangemente were therefore made by which the gas-mixture in a reservoir could be displaced by means of water and the gas from this reservoir made to displace the contents of a second reservoir. The gas-mixture from this second reservoir was passed into a 4 cm.tube 120 cm. long which was kept a t any desired temperature by means of an electric furnace. The far end was partly closed by means of a thick glass plate. It WELS found that once a steady state had been attained the velocity of the gas in the tube could be measured sufficiently accurately by estimating the rate a t which water was introduced into the first reservoir. An observer looking through the plate glass could easily see if ignition occurred. The aub-ignition-temperature for zero velocity was taken to be the lowest temperature at which ignition occurred after the gas aupply had been cut off. The results obtained for two ether-air mixtures are given below in table VII. TABLE VII. Showing the Effect of the Velocity of the Gasmixture &owing through a 4 cm.Tube on the Szlbignition-te?nperature observed. 4 4 per cent. of ether in air. 14 per cent. of ether in air. - - Velocity in Sub-ignition- Velocity in Sub-ignition-cm. per second. temperature. cm. per second. temperature. 0 1 8 7 O 0 186" 6.0 195 1.0 189 12.6 202 5-5 195 - - 8.0 197 - 13.0 202 -The experiments carried out were sufficient to indicate that for very small velocities increase of velocity causes an elevation of the sub-ignition-temperature observed. The velocities dealt with on the manufacturing scale are however of a totally different order, ranging from 100 to 400 cm. per second in various pipes. Influence of the Presence of Glyceryl Trinitrate Ethyl Hydrogen Peroxide and Diethyl Peroxide in the Ether Used.-Several attempts were made t o find if the presence of glyceryl trinitrate in an ether-air mixture affected the sub-ignition-temperature.I n no case was any such effect discernible. I n the experiments for which the results are given in table VIII the glyceryl trinitrate was introduced into the reservoir by passing the air used for making up the mixture through a calcium chloride tube in which glyheryl trinitrate was spread over glass wool the tube and contents bein ‘1 480 WHITE AND PRICE THE IGNITION OF kept a t 40° to 45O. Resulta obtained in a 2 cm. tube were similar to those given below which were determined ’by using a 4 cm. tube. TABLE VIII. Showing the Effect of the Presence of Glyceryl Trinitrate Ethyl Hydrogen Peroxide and Diethyl Peyoxide on the Sub-ignition-temperature of Ether-Air Mixtures.Composition of Mixture. Sub-ignition-temperature. ........................... 5.3 per cent. of ether in air 5.3 per cent. of ether and 1.5 per cent. of diethyl 4-7 per cent. of ether and 0.5 per cent. of ethyl 6.3 per oent. of ether in air saturated with glyceryl 187” peroxide in air .................................. .;... 189 3-7 per cent. of diethyl peroxide in air ............ 189 hydrogen peroxide in air ........................... 182 trinitrate at 20” ....................................... 187 The presence of glyceryl trinitrate did not appear to affect the flame given by the mixture but the presence of the peroxides caused a very fierce flame and generally an explosion. It was considered inadvisable to try to determine the sub-ignition-temperature of ethyl hydrogen peroxide in air.The per-oxides were found to be exceedingly dangerous to handle; even diethyl peroxide exploded violently on one occasion during distillation. SECTION Ir. The Limits of Propagation of Flame in Ether-Alcohol-Air and A cet one-A. ir Miz t ures. Many references are to be found in the literature to the limits of inflammability of mixtures of ether and alcohol with air and some figures are also given for acetone-air mixtures. The limits determined by various workers are given below. Ether-Air Mizture.-Limits of inflammability. first edition 1912 p. 73). m n ! Ghem. Eng. 1916 14 190). 2.7 t o 7.7 per cent. by volume (Brunswig “Explosives,” 50 to 60 grams per cubic metre for lower limit (Marchis Met.2.9 to 7.5 per cent. by volume (Lewes J . Soc. Arts 1915 761). 2.9 to 7.5 per cent. by volume (Schwartz “Fire and Explosion 0.058 to 0-195 gram per litre (Meunier Compt. rend. 1907, Risks,” first edition p. 35). 144 1107) ETHER-ALUOHOL-AIR AND ACETONE-AIR MIXTURIOS ETU. 1481 A 1cohoLAir iKixture.-Limib of inflammability. 4.0 to 13.7 per cent. by volume (Brunswig Zoc. cit.). 4.0 to 13.6 per cent. by volume (Lewes Eoc. cit.). 3.95 to 13.65 per cent. by volume (Bunte and Eitner J . Gaa-3 to 8.4 per cent. by volume (Thornton PTOC. Roy. Soc. 1914, [ A ] 90 280). A cetone-Air Mizture.-Limits of inflammability. beleucht 1901 44 835). 5 to 12 per cent. by volume (Brunswig loc. cit.). 2.15 to 9.7 per cent. by volume (Wheeler and Whitaker T., 1917 111 267).It will be seen that the results obtained vary considerably owing t o the different conditions under which the experiments were carried out and the various igniting sources used. This is to be expected, as the conditions governing the propagation of flame were not properly appreciated until recent years. The definition now adopted is that suggested by Coward and Brinsley (T. 1914 105, 1859) in which inflammability is regarded as a specific property of a mixture independent of the size and shape of tho vessel in which it may happen to be contained and also of any particular type of igniting arrangement. They propose to define a gaseous mixture as inflammable per se a t a stated temperature and pressure if and only if it will propagate flame indefinitely the unburnt portion of the mixture being maintained a t the original tempera-ture and pressure.On this definition inflammability is a property of the mixture itself although a function of the temperature and pressure. Dilution-limits however rarely vary much throughout the usual range of variation of laboratory temperature and pressure. It will thus be seen that in order to obtain satisfactory results in the estimation of dilution-limits it is necessary to use a vessel (1) of such size that any cooling of the gas-flame by the walls can be neglected and (2) of sufficient length to enable a sound judgment t o be made as to whether a flame would propagate indefinitely or no. For every gas-mixture examined propagation-limits were deter-mined for three directions-upward horizontal and downward.Preliminary work seemed to indicate that in a glass tube 5 cm. in diameter by using a sufficiently powerful initiator it; was possible to force a flame through a mixture below the limit of pro-pagation to the end of the tube unless it was a t least 120 CM. long. All the tubes for limit work were therefore made a t least 150 cm. in length. The tubes consisted of: (1) Glass tubes 2.5 cm. in diameter 1482 WHITE AXD PRICE THE IGNITION OF (2) Glass tubes 5 cm. in diameter. (3) An iron* tube 5 cm. in diameter. (4) An iron tube 15 cm. in diameter and 300 cm. long. The glass tubes and the 5 cm. iron tube were 150 cm. long. The glass tubes were closed a t both ends by gas-tight stopcocks of 4 mm. bore and a similar cock was fitted t o one end of the iron tube, where a 5 cm.glass observation piece was cemented for observa-tion purposes. The cocks in the case of the 15 cm. iron tube were of brass and of 6 mm. bore. I n this tube inflammation was observed through three equidistant windows of thick plate glass, which were cemented into holders on the tube. These windows gave much trouble and it was found impossible to render them gas-tight by using cement alone. Accordingly caps were soldered over each window in such a way that by inserting a 3.7 cm. rubber stopper into the observation hole left in the cap the whole apparatus could be made gas-tight. The stoppers were removed immediately before firing. This tube was filled by means of a filler similar to that shown in Fig. 1 the end of the filler being made to project well through a tightly fitting piece of rubber tubing drawn over one of the cocks.The filling was carried out precisely as described previously a correction being always applied for the vapour of the solvent present in the air above the liquid in the filler. In the case of all the smaller tubes the fillers were provided with ground-glass joints fitting pieces sealed on to the tubes concerned. All the air passed in t o make up any mixture containing alcohol or acetone was carefully dried by passage through a calcium chloride tube. The calibration of the tubes was carried out by weighing the quantity of water necessary to fill them. Ignition was effected by passing a spark from an induction coil between two electrodes of stout platinum wire separated by an air gap of 1 cm.the current being obtained from six 2-volt accumulators. I n the glass tubes originally used the platinum was sealed through the glass but as good sealing glass became scarce, this was found to be impracticable and the electrodes used for all the tubes consisted of platinum in glass mounted in rubber stoppers. The original method of mixing the gases was by allow-ing the tube to remain for several hours but this became in-advisable when rubber was brought into contact with the solvent-laden air. A little mercury enabled efficient mixing to be carried out by shaking the tube but i t was found that this affected the results obtained and finally small glass beads were used. Corn-* This and the other iron tubes used in the investigation consisted of terne-Plate that is sheet-iron coated with tm alloy of lead and tin ETHER-ALCOHOL-AIR AND AOETONE-AIR MIXTURB~B ETU.1483 parative tests showed that when using an adequate number of beads Hhaking.a 5 om. tube for twenty minutes gave satisfactory mixing It was alao shown that under these conditions the same results were obtained whether the electrodes were held by small rubber stoppers or were sealed through the glass. Throughout the course of the work the only tube that caused trouble was the 5 cm. iron tube. The various cements used for fastening the glass observation cap to the main body of the tube seemed to hold solvent and the results obtained for this tube cannot be conaidered FIG. 5. 4 A. as trustworthy as those obtained with the others.The mixing of the content of the 15 cm. iron tube was done very efficiently by rolling a 12.5 cm. perforated hollow copper ball from end to end. The apparatue used for determining the upper limit of propa-gation for alcohol-air and certain ether-alcohol-air mixtures con-sisted of a 5 cm. glass tube jacketed by enclosure in a wider glass tube so that hot water could be continuously circulated round it. The arrangement used i s shown in Fig. 5. Two sets of this apparatus were fitted up one as shown in th 1484 WHITE AND PRICE THE IGNITION OF sketch arranged for experiments on downward propagation with the electrodes at the same end of the tube as the ground-glass joint for filling the tube and the other arranged for upward propaga-tion in which the electrodes were a t the end away from the ground-glass joint.For horizontal propagation either of the above tubes was used and placed horizontally before firing. Some difficulty was encountered in sparking the mixtures contained in this apparatus but by enclosing the leads in glass tubes this was finally overcome. Naturally mixing in these tubes could only be accom-plished by allowing the tube to remain for some time. The procedure in the case of any mixture can be seen by a consideration of the results given below. Experiment 21.-Glass tube 5 cm. in diameter. Solvent mixture used 75 per cent. of ether and 25 per cent. of alcohol (by weight). Lower limit downward propagation. Temperature 19O. Percentage of solvent-vapour in gas-air mixture (by volume).2-70 ................................. Complete ignition. 2.40 ................................. Flame just started. 2-00 ................................. Complete ignition. 2-50 ................................. Partial ignition. 2.55 ................................. Flame went nearly to 2.57 ................................. Flame went very LimiC2.57 per cent. the end. slowly to the end. I n the case of a lower limit an accuracy of 0.02 per cent. was aimed a t ; in the case of an upper limit 0.05 per cent. was taken. I n every instance just before firing the cock furthest removed from the electrodes was opened ta allow a free passage for the gases. When the limit of propagation was being determined for a mixture of ether and alcohol a liquid containing the requisite proportions of these two solvents was made up and used.A test experiment showed that this gave the same result as was obtained when the two solvents were weighed into the tube sepmately. Ether-AZcohol-Air Mixtures.-The results obtained for ether-alcohol-air mixtures in glass tubes are shown in table IX. The experimental results obtained with the 2.5 cm. tubes are not so trustworthy as those determined in larger tubes as can be seen from the results themselves. For example the result obtained for the lower limit of an ether-air mixture is least for downward propagation and other anomalies could be pointed out in the same way. These irregular results were probably due to the fact that it was only for downward propagation that the flame travelled more or less steadily.For upward propagation it was sometime TABLE I X . Showing the Limits obtained for the Propagation of Flame in Ether-in Glass Tubes. The limit figures given show the percentage volume occupied by Direction Percentage composition of upw/ards. Horizontally. mixture (by weight). Diameter - b -100 0 2-5 18.50 2.35 6.16 75 25 YS 6.95 3.15 7-35 Y Y - 3-52 -Y9 - 4.35 -1 Y - 5-02 -100 0 5 15-75 1.93 8.00 75 25 Y 11.70* 2.40 10.95* 60 50 1 ) 10.70* 2.89 10*36* 25 75 9 ) 12*00* 3-53 11-50* 0 100 I t 18*95* 4-24 13*80* Lower upper limit. limit. Of tube upper Ether. Alcohol. in cm. limit. Per cent. Per cent. Per cent. 50 50 25 75 0 100 * The figures marked thus were determined in the jacketed tube at 60° and are, the others whioh were determined at air-temperatur 1486 WETTE AND PRIOE THE IGNITION OIT obviously jerked out.Wheeler’s work has shown that only a very slight change in the limits takes place when the diameter of the glass tube is increased beyond 5 cm. so that this was the largest size of glass tube used. His work however was chiefly carried out with permanent gases. The most noticeable fact brought out in table IX appears to be the great difference between the results obtained for the upper limit for upward propagation and those obtained for propagation in other directions. These differences which are normally due to convection currents set up by the flame are not so great for per-manent gases. The difference bet.ween the upper limits for hori-zontal and for upward Propagation is most marked and it almost appears as if 8 different type of propagation were brought into being.It is quite conceivable that the heated gases rising in the tubs are responsible for the initiation of a cool flame. The difference is not so great in the case of alcohol as it is for ether. The results for ether-alcohol-air mixtures in a 5 cm. glass tube are shown in Fig. 6. The results given for the upper limits were all determined a t 60°. The graphed results for the lower limits and the upper limit for downward propagation form good approximations to straight lines but this is not the case for the other two curves A t first sight it seems very strange that for the upper limit for upward propagation the results for a mixture containing equal weights of ether and alcohol should be more than 6 per cent.less than the corresponding figure for either ether or alcohol. A possible explanation appears to be afforded by an examination of the sub-ignition-temperature curves given in Fig. 3. From these it will be seen that the addition of alcohol to an ether mixture raises the sub-ignition-temperature so that the slope of the two upper curves near the 100 per cent. ether point is in the direction to be expected. Similarly the slope near the 100 per cent. alcohol point can be explained when it is remembered that it takes an appreciable quantity of ether to cause any deoided lowering of the sub-ignition-temperature of an ether-alcohol-air mixture. That there is no apparent irregularity corresponding with that seen when the percentage of ether is between 1 and 2 per cent.on the sub-ignition-temperature curves may be due to the fact that ao few points have been determined on the limit curve; but it is far more likely to be due to the fact that the sub-ignition-temperature obtained for an ether-alcohol-air mixture containing say 2 to 2.5 per cent. of ether is due solely to the ignition of the ether present and that the alcohol takes little part in the reaction. These remarks do not apply to curve C Fig. 6 ETHER-ALUOHOGAIR dlqg AOETONB-AIR MEETORBIS ETC. 1487 aa in that case the flame obtained is undoubtedly that of ordinary combustion. The limits of inflammability of a mixture of two or more gases with air are connected with the limits of the components of the mixture by Le Chatelier's rule which states that if n d n" .. FIG. 6. 0 Percentage of ether. Pwcetttags of akohol Composition of aolvelzt mixture uaed (by weight). 28 60 76 100 are the percentages of various combustible gases in a limit mixture which will just propagate flame and N I?/ iV// . . . the limiting percentages of the separate gases that can propagate flame then n n' n" - + + __ + . . . =1. N N' N" In table X are given the values for Le Chatelier's constant 1488 WEITE AND PRICE THE IGNITION O$ calculated from the results found for various ether-alcohol-air mixtures in 5 cm. glass tubes. TABLE X. Showing the Value obtained for Le Chatelier's Constant for Various Ether-Alcohol-Air Mixtures in 5 em. Glass Tubes at 20k20, Value of constant in mixture of following percentage composition by Maximum weight.percentage < \ variation ). Direction of 26 ether. 50 ether. 76 ether. from Limit. propagation. 75 alcohol. 50 alcohol. 26 alcohol. unity. Downwards 0.984 0.971 0.983 3 Horizontal ... 0.833 0.774 0-830 33 Upwards ... 0-646 0.589 0.663 41 Downwards 0.989 0.967 0.980 3 Horizontal ... 0.995 0.985 0.992 1 Upwards ... 1.004 0-993 1.00'7 1 The figures used for the upper limits in this table were all found at 60° those for the lower being determined as usual within 2* of 20°. It will be seen that in all cases for the lower limit and for downward propagation in the case of the upper limit Le Chatelier's rule holds for mixtures of ether and alcohol with air, and consequently the limits for a mixture containing any propor-tion of ether and alcohol can be calculated with an error of not more than 3 per cent.For horizontal and upward propagation, however the rule breaks down entirely. As would be expected, the greatest deviation from the rule always occurs for a 50 per cent. mixture. I n table XI are given the.results obtained when the same mix-tures were ignited in 5 cm. and 15 cm. iron tubes. The upper limits for ether-air mixtures are given in table XII. TABLE XI. Showing the Results obtained in Iron Tubes of 5 and 15 cm. Diameter for the Lower Limits for the Propagation of Flame in Certain Ether-Alcohol-Air Mixtures at 20 k 3". Percentage composi-tion of solvent mix-ture by weight. Ether. Alcohol. -100 0 100 0 75 25 50 50 25 75 0 100 Lower limits for propagation of flame.Diameter of f l I tube in cm. Upwards. Horizontal. Downwards. 5 2.24 2.29 2.34 15 1.73 1-80 1-93 15 2.24 2.30 2-46 15 2.81 2.89 3.02 15 3-48 3-53 3.69 16 4.16 4.23 4.37 ETHER-ALCOHOL-AIR AND ACETONE-AIR MIXTUBES ETC. 1489 TABLE XII. Showing the Upper Limits for Propagation obtained for Ether-Air Mixtures in 5 and 15 ern. Iron Tubes. Value of limit and direction of pro-pagation. A Diameter / I of tube. Upwards. Horizontal. Downwards. 5 15.45 7.96 6.70 15 23.30 22-30 6.50 A comparison of these results with those given in table IX shows that for all three directions of propagation the lower limit as found for 5 cm. tubes is greater when the tube is made of iron, as would be expected from the greater conductivity of this material.The reverse relation holds in the case of the upper limit obtained for ether-air for upward and horizontal propagation but in the case of the downward propagation the figure obtained for the iron is greater than that obtained for a glass tube of a similar size or even for the 15 cm. iron tube. As this result appeared peculiar, a fresh determination of this limit was made but the composition of the limiting mixture was found to be the same as that found in the first experiment. A comparison of the limits obtained in the 15 cm. iron tube with those previously determined (see tables IX XI and XII) is instructive. It will be seen that in every case the lower limit of a mixture is least in the case of the 15 cm.tube. The difference is very appreciable where a mixture contains a fair amount of ether but is not so great where alcohol is present in excess. The upper limit again is always found to be greatest in the case of the 15 cm. tube if we except the anomalous result. obtained for downward propagation determined in the 5 cm. iron tube. These results may be due to a decrease in the cooling effect of the walls or may possibly be due to turbulent motion in the gas caused by convection currents as found by Wheeler and Mason (T. 1917 111 1044) in the case of velocity of flame. An item in favour of the latter supposition is provided by the exceedingly high figure obtained for the upper limit for horizontal propagation in the 15 cm. tube. On the other hand the flame observed in the case of upward and horizontal propagation in the 15 cm.tube resembled very closely the cool flame of ether and the character-istic odour following such a flame was observed. The lower-limit results for iron tubes are shown graphically in Fig. 7. The figures in table XI11 show that Le Chatelier’s rule holds moderately well for the lower-limit results obtained in the 15 cm. iron tube 1490 WHITE AND PRXCE THE IGNITION OF TBLE XIII. Showing the Value Found for Le Chatelier’s Constant from the Figures obtained for the Lower Limit for Propagation wing Bther-Alcohot-Air Mixtures in the 15 cm. Zron Tube. Values of constant given by mixture of percentage composition by weight shown. Perc?ntage Direction of 26 ether. 60 ether. 76 ether.variation propagation 76 alcohol. 60 alcohol. 26 alcohol. from unity. / A I maxlmum DOWXIW~~~.H ............ 1.028 1.025 1.026 3 Horizontal ............... 1.028 1.036 1.022 4 UpwarilS ............... 1.039 1.038 1.031 4 FIG. 7. 60 25 0 0 26 60 75 100 Percentage of ether. Percedage of alcohd. Co?nposiCion of the ether-alcoho2 mixture wed (by weight). Acetone-Ether-Air Mixtures.-Owing t o the differences in resulte obtained for 6 cm. glass and 15 cm. iron tubes particularly for ether-air mixturea it .was decided t o determine the propaga ETHER-ALCOHOL-AIR AND ACETONE-AIR NIXTURES ETC. 1491 tion of flame limite of certain ether-acetone-air mixtures in glass and iron tubes as it was considered likely that results differing from those published by Wheeler and Whitaker (Zoc.cit.) for acetone-air mixtures would be obtained. The results of our experiments are shown in table XIV those of Wheeler and Whitaker being given in table XV. TABLE XIV. Showing the Propagation of Flame Limits obtained for Acetone-Ether-Air Mixtures using Various Iron and Glass Tubes a t 20 f 20. Percentage of solvent in limit mixture and position of r A \ mixture by Material Upwards. Horizontal. Downwards. diameter of Upper Lower Upper Lower Upper Lower Ether. Acetone. tube. limit. limit. limit. limit. limit. limit. 0 100 Iron 6 cm. - 3.80 - 3.90 - 4.00 Percentage com- direction of propagation. weight. and - -0 100 Iron 15 cm. 12-40 2.88 12.40 2-89 10.90 3-11 0 100 Glass 5 cm. 12.20 2.89 9.15 3.04 8.35 3-16 25 75 $ 9 11.20 - 8-56 - 7.75 -50 50 ?9 11.70 2.34 8.25 2.39 7.25 2.49 75 25 Y Y 13.20 - 8.15 - 6.65 -100 0 Y Y 15-75 1.93 8.00 2.05 6.15 2.15 TABLE XV.Showing the Propagation of Flame Limits as determined by Wheeler and Whitaker for Acetone-Air Mixtures in Glass Tubes of Various Diameters. Percentage of acetone in limit mixture and direction of propagation. Upwards. Horizontal. Downwards. - - - / \ Diameter of Upper Lower Upper Lower U&pp Lo27 tube in cm. limt. limit. limit. limit. 2-6 7.6 2-30 6.7 2.40 6.5 2-76 6.0 9.5 2.20 9.3 2-25 8-3 2.40 10.0 9.7 2-15 9.5 2.20 8.5 2-35 It will be seen that our results differ considerably from those In most cases they are considerably higher. previously published 1492 WHITE AND PRICE THE IGNITION OF The explanation is almost certainly to be found in the fact that in our method the solvent was weighed directly into the tube, whilst in the other the acetone present in any mixture was estimated by analysis.That our method is the more accurate as well as the easier is obvious but such a large discrepancy can only be explained by some abnormality in the behaviour of acetone during storage if the methods of analysis employed were not faulty. That such abnormal behaviour does take place when acetone vapour is stored over mercury is rendered extremely probable when the facts underlying the molecular association of acetone suggested in the paper by Wheeler and Whitaker are considered. I n this connexion too a quotation from the above paper might prove instructive. When discussing the analysis of the mixtures used the following statement is made “ A supply of air was saturated with acetone vapour at 15O and 760 mm.when it con-tained 13.5 per cent. (by volume) of acetone and used as a stock mixture from which the experimental mixtures could be prepared by the addition of air. . . . Consistent results were obtained by either of the absorption methods of analysis. Thus a mixture, known to c o n t a i n about 6.5 per cent. of acetone gave on analysis: “(1) Sodium hydrogen sulphite method . . . 6-50? 6.45 6.54, 6-55. “(2) Distilled water . . . 6.40 6.56 6.54 6-50 6.51 6.51. ‘‘ Absorption by distilled water seemed therefore to afford a sufficiently accurate method of analysis.” The mixture “known t o contain about 6.5 per cent. of acetone ” was apparently made up by diluting the requisite quantity of the stock solution with a calculated volume of air.The accuracy of the method of analysis appears to be assumed from the fact that results approximating closely t o the calculated figure were obtained. An examination of published figures for the vapour pressure of acetone a t 15O however shows that a stock solution of air saturated with acetone vapour a t this temperature a t 760 mm. pressure would contain more than 19 per centn. of acetone (by volume) the vapour pressure of acetone a t 15O being given by Sameshima ( J . Amer. Cheem. Soc. 1918 40 1482) as 147 mm. Extrapolation from Regnault’s results gives a very similar figure-about 150 mm. Raising Wheeler and Whitaker’s results in the ratio of 19:13*5 would often bring them much nearer t o those obtained by us.The results obtained for lower limits in the 15 cm. iron tube are strikingly similar to those obtained in a 5 cm. glass tube (see table XIV) and for upward propagation the upper limits are also very near. There are however very marked differences in the other figures given for the upper limits. It is worthy of note tha ETHER-ALCOHOL-AIR AND ACETONE-AIR MIXTURES ETC. 1493 the upper limits for upward and horizontal propagation are here identical in the case of the 15 cm. tube. The results obtained when using the 5 cm. iron tube show clearly what a large effect the conductivity of the material of the tube has in this case. The results obtained in 5 cm. glass tubes for the propagation of flame limits of ether-acetone-air mixtures are shown graphically in FIU.8. Percentage of ether. Percentage of acetone. Composition of solvent mixture wed (by weight). 0 25 60 75 100 Fig. 8. It will be noticed that the upper-limit curves present the peculiarities commented on in the case of ether-alcohol-air mixtures although to a less extent. The figures given in table XVI show that Le Chatelier’s rule holds moderately well for ether-acetone-air mixtures except in the case of the upper limit for upward propagation 1494 WHITE AND PRICE THE IaNITION OF TABLE XVI. Showing Values obtained for Le Chatelier's Coastant for the Limits for Propagation using Ether-Acetone-Air Mixtures 2% the 5 cm. Glass Tube at 2052O. Direction of Limit. propagation. Downwards Horizontal Upper Upwards Lower Downwards Lower Horizontal Lower Upwards Value of constant given by mix-ture of percentage composition by weight shown.25 ether. 50 ether. 75 ether. 75 acetone. 50 acetone. 25 acetone. 0.997 1.005 0.997 0.962 0.959 0,981 0.875 0.866 0.910 - 0.952 -- 0.953 - - 0.987 -T A \ Percentage [maximum variation from unity. 1 4 13 6 6 1 Znfluence of Temperature.-The influence of temperature on the limits of inflammability of gaseous mixtures has been studied by Bunk and Roszkosski ( J . Gasbeleucht. 1890 33 491 524 535, 553)) Taffanel (Compt. rend. 1913 157 595) Burrell and Robert-0011 (United States Bureau of Mines Technical Paper No. 121, 1916)) and Mason and Wheeler (T. 1918 '113 45). The experi-mental work of Bunk and Roszkosski appears to have been defective but the other workers found that the inferior limit of inflammability of methaneair mixtures was lowered by increasing the temperature of the gas-mixture before ignition Mason and Wheeler also showed that the upper limit of inflammability of methane-air mixtures became much greater under these conditions, so that increasing the original temperature of the gas widens the limits of inflammability of methane-air mixtures.This would be expected from the fact that the self-propagation of a flame t.hrough a combustible mixture is only possible when the heat due to the reaction between the combining gases is sufficient to make up for losses due t o radiation conduction and convection whether the heat lost is dissipated or utilised in raising adjacent layers of the gas t o the inflammation temperature.The heat; of reaction neces-sary and the heat dissipated must obviously be less in the case where the original temperature of the gaseous mixture is higher. A few figures are given below t o show t o what extent the limits of inflammability are affected by temperature ETHER-ALCOHOL-AIR AND ACETONE-AIR MIXTURES ETC. 1496 TABLE XVII, Showing some Results obtained b y Mason and Wlzeeler for the Downward Propagation of Flame in Mixtures of Methane and Air. Initial temperature. Lower limit. Upper limit. 20" 6.00 13.40 100 5.45 13.50 200 5-05 13.85 300 4.40 14-25 500 3.65 15-35 700 3.25 18.75 I n the circumstances it was decided that it would be unnecessary to do more than find the change in the upper limit of ether-air mixtures with temperature.These experimenb were carried out in the jacketed tube utilised for the upper limits of alcohol and ether-alcohol-air mixtures. The results obtained are shown in table XVIII. It will be seen that a decided rise in the upper limit for propagation takes place when the initial temperature of the mixture is raised through 40°. TABLE XVIII. Showing how the Upper Limit for the Propagation of Flame Varies with the Initial Temperature of the Ether-Air Nixture Used. Direction of propagation. Limit at 20'. Limit at 60'. Upwards ...... 15.75 17.05 Horizontal . . . 8.00 13.00 Downwards ... 6.15 7.48 Influence of Pressure.-The influence of pressure on the limits of inflammability of gases over any large range is by no means easy to predict although it is well known that the lower limit of in-flammability of many gas-air mixtures increases a t diminished pressures.Terres and Plentz ( J . Gasbeleucht. 1914 57 990, 1001 1016 l025) Burrell and Robertson (Zoc. cit.) and Mason and Wheeler (Zoc. cit.) have investigated the effect of pressure on the limits of inflammability of mixtures of methane with air. The general conclusions to be drawn from their work appear t o be that, below atmospheric pressures decreasing the pressure narrows the limits of inflammability but that above atmospheric preasure, increasing the pressure raises both tbe limits of inflammability. The work done by us was confined to pressures at or below atmo-spharic prwsure a i d the results are shown in table XIX and XX 1496 WHITE AND PRICE THE IGNITION OF TABLE XIX.Showing the irnnflztence of Pressure on the Limits for Horizontai Propagation of Flame in Et her-Air Mixtures. Pressure in m. 770 751 600 520 460 460 420 400 300 200 100 50 Percentage of ether in mixture. wk-At lower limit. At upper limit. 1.87 12.90 - 10.50 - 9.20 1-88 - 8.20 - 7.90 - 7.80 1.92 7.30 2.08 6.80 2.33 6.10 2.99 5-00 --TABLE XX. Showing the Influence of Pressure on the Limits for Downward Propagation of Flame in Ether-Air Mixtures. Pressure in mm. 600 600 400 300 200 100 50 Percentage of ether in mix-ture at lower limit. 6.20 6.20 6.20 6.20 5.90 5-50 No ignition.It will be noticed that the results obtained near atmospheric pressure in the case of these experiments differ appreciably from those found by the ordinary method as given in table IX. This is due to the fact that all the experiments given in tables XIX and XX were carried out with both cocks closed. The type of ignition obtained was also very different ; for instance the ignitions obtained when determining the upper limit for horizontal propaga-tion under 600 and 751 mm. pressure were characteristic slow cool flames which could not be seen except in a totally darkened room. It wits found that any attempt to determine the limits for pro-pagation of ether-air mixtures for pressures greater than atmo-spheric in the glass tubes available merely shattered the tube.The curves given by plotting pressure against the percentage of ether in the limiting mixture are given in Fig. 9. That for hori-zontal propagation is interesting. It was a t pressures above that a t the peculiar bend marked x that the cool flame became notice ETHER-ALCOHOL-AIR AND ACETONE-AIR MIXTURES ETC. 1497 able Below this pressure the flame was of a green colour and traversed the tube very rapidly in a manner similar to that noticed for the lower limit a t corresponding pressures. Influence of VeZelocity .-Under present-day conditions of solvent-recovery a good portion of the solvent-air mixture is often in rapid motion. It therefore became a question of determining so far as was possible in the laboratory the effect of velocity on the limits of propagation of solvent-air mixtures.Owing to the fact that no FIU. 9. Parcentage of etheriin mixture. real approximation t o manufacturing conditions could be attained, the work done was confined to ether-air mixtures. It has long been known that a moving mixture of combustible gas and air too weak to propagate flame can carry a cap of flame t o a great distance from an igniting source. Wheeler has also proved that a mixture below the lower limit of propagation when in a quiescent state can often inflame when agitated. The speed of propagation of flame is also notably dependent on the degree of mechanical agitation of a mixture and various experiments on the effect of agitation on gas-mixtures and on the rate of development of pressure when gas-mixtures are ignited are given by Clerk an 1498 WHITE AND PRICE THE IGNITION OF Hopkinson ( R e p .Brit. Assoc. 1912 ZOO) Clerk (“ Ganet Lecture,” Junior Institution of Engineers 1913) and Wheeler (this vol., p. 81). So far as we know however no figures have as yet been given for the effect of the velocity of a gas-mixture on the limits of its propagation of flame. The methods used for moving the mixture and determining its velocity were those described under sub-ignitisn-temperature. Great care had to be taken in determining the upper limit for pro-pagation against the gas-current as the flame passed with great velocity down the 10 mm. bent glass tube joining the limit tube t o the reservoir. This gave very little time for preventing the flame from getting into the reservoir.The results obtained are given in sable XXI. TABLE XXI. Showing the Effect of the Linear Velocity of an Ether-Air Mixture on its Downward Propagation of Flame Limits as determined in a 5 cm. Glass Tu6.e at 20*2O. Flame moving in the direction of gas current. , Percentage of ether in mixture at 0 2-13 6-15 1 1.97 6-40 3.5 1.95 6.50 9 1.95 6-66 Percentage of ether in mixture at Velocity in cm. per sec. lower limit. upper limit. Flame moving against the gas current. 0 2.13 6.15 1 - 6.25 3.5 - 6.25 9 - 6.25 It waa found to be impossible to find the lower limit of propaga-tion when the flame was moving against the stream as it merely became a question of the velocity of the stream as compared with that of the flame in the mixture used.It will be seen from the upper portion of the table that the velocity of the gas-current affects very appreciably the percentage mixture which will pro-pagate flame. That a portion of this change is due to turbulence caused in the gas however appears to be very likely for in the cases tried when the flame moves against the gas-current with any real velocity the upper limit is always the same. The figures given for zero velocity in table XXI are those found with one cock closed in the ordinary manner. As conditions are slightly different when both cocks are open it was decided t o try BU& ara experiment. The upper limit found under these condition ETHER-ALCOHOL-AIR AND ACETONE-AIR MIXTURES ETC. 1499 was 6.30 per cent. but the convection due to the flame probably caused this figure to be a little high on account of the air drawn into the tube during the passage of the flame.It almost appears as if when a flame is travelling against a gas-stream the turbulence due t o the velocity of the stream practically balances the effect of that velocity in hindering the propagation of flame. In&uence of the Presence of Glyceryl Trinitrate Diethyl Peroxide and Ethyl Hydrogen Peroxide. In the experiments to determine the effect of glyceryl trinitrate on the limits of propagation for ether-air mixtures the mixture used was charged with glyceryl trinitrate as described under the experiments on the determination of sub-ignition-temperatures. The results obtained when using ether-air mixtures containing diethyl peroxide and ethyl hydrogen peroxide are given in table XXII.TABLE XXII. Showing the Effects on the Limits of Propagation of Flame of adding Amounts of GEyceryl Trinitrate Diethyl Peroxide and Ethyl Hydrogen Peroxide to Certain Ether-Air Mixtures. Direction of propagation. Upwards . . . . . . Downwards ... Upwards . . . . . . Downwards ... 9 , 9 9 1 9 Limit. Lower Mixture used (with air). Ether. Up& Lower Ether saturated with glyceryl Upper Y f Lower Diethyl peroxide. 9 ) Y f trinitrate a t 20". , Ether Containing 25 per cent. of diethyl peroxide by weight. Ether containing 10 per cent. of 80 per cent. ethyl hydrogen peroxide by weight. Upper 9 Lower Upper $ 9 Percentage of ether in limit mixture .1.93 2-15 6.15 1.95 6.15 2-34 2-18 10.1 2-17 6.5 The peroxides of ether are calculated as ether in making up the percentage volume occupied by the solvent in the limiting mixture. It will be seen that glyceryl trinitrate appears to have no effect on either limit and that the peroxides have little effect on the lower limit but that they raise the upper limit very appreciably. The glyceryl trinitrate did not appear to affect the flames given, but the flames when peroxides were present were invariably fiercer than when ether alone was used except perhaps a t the extreme limit. VOL. cxv. 3 1500 WHITE PRICE THE IGNITION OF SECTION 111. Investigatioit of Various Means of Ignitio?E. A series of experiments was carried out in which sparks obtained by various means were used for attempting to ignite ether-alcohol-air mixtures.It was found that steel to steel emery to steel and pyrites to steel sparks appeared to be unable to cause the inflamma-tion of any of the many mixtures tested. Ferro-cerium to steel sparks however ignited most mixtures very readily. The igniting powers of a small gas flame and a moderately powerful electric epark appeared t o be of the same order and both almost invariably gave rise to ordinary combustion the limits of propagation of flame being naturally identical in the two cases. I n the case of ether-alcohol-air mixtures quick heating of a mixture up to but not far above its sub-ignition-temperature seemed t o give rise to a cool flame which had limits for propagation varying from those of ordinary inflammation.The Cool Flame.-The difference in propagation limits for the two methods of combustion was particularly noticeable in the case of concentrated ether-air mixtures as the flame travelled easily through a 20 per cent. mixture in a horizontal tube 4 cm. in diameter although the upper limit for the propagation of ordinary combustion in a 5 cm. tube would be 8 per cent. No deter-minations of the limits for propagation of a cool flame were made, but experiments carried out for other purposes indicate that it is unlikely that such a flame could propagate downward through a mixture containing much more than 6 per cent. of ether. This flame was occasionally observed when electrical ignition was utilised, more particularly with high concentrations of ether or low pressures.It appeared as stated by Perkin to require very little oxygen and the products of combustion were characteristic. It was found that the addition of less than 1 per cent. of oxygen to a mixture of 9 per cent. of ether in nitrogen was sufficient to give luminous combination below 220O. The increase of temperature caused by this flame in a mixture containing less than 3.5 per cent. of ether and heated to its sub-ignition-temperature wids insufficient to be indicated by the fine thermo-couple registering the tempera-!are of the gas in the ignition tube. The increase of pressure caused by it was also very small. This was measured roughly by ib effect on a column of mercury so arranged that after ignition t&e mercury in both limbs of a U-tube would be level.The mean of three experiments with a 3.9 per cent. mixture gave a momentar ETHER-ALCOHOL-AIR AND ACETONE-AIR MlXTURES ETC. 150 1 increase of pressure equal to 3 or 4 cm. Mixtures containing more ether gave far greater pressures. It was found that a 0.3 cm. mesh iron gauze or a 0.2 cm. mesh brass gauze prevented the passage of a cool flame down a glass tube 7 cm. in diameter. Discussion of R esul t s . The sub-ignition-temperature figures given above agree fairly well with ignition-temperatures previously published for alcohol and acetone. The sub-ignition-temperature given for ether-air mix-tures however whilst agreeing almost exactly with the ignition-temperature given by Alilaire differs notably from the other figures available.The difference is probably to be accounted for by the fact that in the methods employed to obtain these no account was taken of the cool flame of ether-the cool flame of alcohol can only be obtained near the temperature a t which an explosion or ordinary combustion occurs directly. This may be justifiable and necessary in the determination of ignition-temperatures but involves the neglect of a phenomenon which can and very often does give rise t o ordinary combustion under suitable conditions. Moreover these conditions are precisely those liable to obtain during solvent-recovery on the manufacturing scale namely the presence of a large volume of the solvent-air mixture and some degree of confinement. That ordinary combustion of a dangerous nature could be caused by heating an ether-air mixture in glass tubes to 1 8 7 O was proved again and again when using 4 and 5.5 cm.tubes particularly if the percentage of solvent lay between 5 and 9. That this result was a genuine one was proved by stopping a current. of ether in air flowing along a glass tube kept a t 1 8 7 O . Ignition of the ether occurred in every case. The method employed to determine sub-ignition-temperatures thus appears to be a practical one and also has the advantage of being easily adaptable to determine the effect of substituting for glass any material that might be used in manufacture. The ignition observed by Alilaire must indubitably have com-menced as a cool flame. 'The temperatures necessary to obtain such a flame in mixtures containing fair quantities of ether as shown by us are fairly near the temperatures attainable in a steam-heated building particularly when it is considered that the presence of metals lowers the sub-ignition-temperature appreciably.On the other hand the results previously obtained for the ignition-3 K 2502 WHITE AND PRICE THE IGNITION OF temperature of ether-air mixtures are far above those one can conceive of being attained in such a building except in the most extraordinary circumstances . The results show that a quiescent gas appears to be more easily ignited than one in motion but the experimental work covers only a very small range of velocities and in any case the propagation of flame is more easily and quickly carried out by gas in motion.The presence of glyceryl trinitrate in a gas-mixture as was anticipated from its amount does not seem to affect the tempera-ture of sub-ignition or the limits of propagation of flame. The peroxides sometimes present in ether in very small amounts can, however affect both its ignition and its propagating qualities if present in sufficient quantity. Our work seems to indicate that their influence in causing primary ignition could only be inappreci-able although it is quite conceivable that they could well affect the change from cool to ordinary flame. Reduction of pressure appeared to cause a lowering of the sub-ignition-temperature of the mixtures examined but the effect of pressure alone within the range of variation of atmospheric pressure can scarcely have a practical influence on the ignition of the solvent-air mixtures as for ether-air for example a reduction of pressure of 10 cm.near atmospheric pressure caused a variation in the sub-ignition-temperature of less than 2 O . The only phenomenon that could be expected to reduce the sub-ignition-temperature of ether-alcohol-air and ether-air mixtures below the danger limit is thus that described as shock ignition. With a difference of pressure of less than half an atmosphere it was possible by this method to ignite a gas-mixture a t least 170° below its sub-ignition-temperature so that it is quite conceivable that the development of sudden differences of pressure on the manu-facturing scale might easily be the determining factor in bringing about ignition of the solvent-laden air.Exactly how this is to be brought about can only be conjectured as our inside knowledge of gas-ignition particularly as regards this fresh phenomenon is very limited. The present work has shown how many accidents could happen but much remains to be done before any sound explanation can be given of such a conflagration as was described in The Times of March 28th 1919 when a bottle of ether exploded in a military hospital a t Southage. According to the same report, explosions of bottles of ether are of somewhat frequent occurrence. The results given in the older work for the limits for propaga-tion of flame in ether-air mixtures are 1.8 per cent. and about 9 per cent. the latter being apparently far .out whilst those for alcohol-air mixtures agree fairly well with our results particularl ETHER-ALCOHOLAIR AND ACETONE-AIR MIXTURES ETC.1503 as regards the lower limit. The change from 5 cm. glass to 15 cm. iron tube affects the results for the upper limit for horizontal and upward propagation in ether-air mixtures very materially the limits becoming well over 20 per cent. in each case instead of 8 per cent. for horizontal propagation and 16 per cent. for upward propagation. The extreme limits determined for ether-air mix-tures are thus 1.73 and 23.30 per cent. The upper limit for pro-pagation in alcohol-air mixtures in 5 cm. glass tubes was found to be 18.95 at 60°. As this figure was well above the highest con-centration of alcohol vapour obtainable during normal recovery, there was no point in repeating this in the 15 cm.iron tube. 'The lower limit of propagation for alcohol-air mixtures was only very slightly altered in the large iron tube falling from 4.24 per cent. in the 5 cm. glass tube to 4.16 per cent. The results for the propagation of flame in ether-alcohol-air mixtures obtained during this investigation are distinctly interest-ing. It is found that Le Chatelier's rule holds for all directions of propagation for the lower limit and for the upper limit for down-ward propagation. The rule does not hold for the other two direc-tions of propagation for the upper limit the discrepancies being very considerable in the case of upward propagation. Wheeler's work on acetone-air mixtures has already been discussed and it may suffice here to state that the limib given by him are 2-15 and 9.7 per cent.our results being 2.88 and 12-40 per cent. The lower limit of 5 per cent. given by Brunswig is obviously wrong but the upper-limit figure of 12 per cent. is very near that found by us. It will be seen that the effect of temperature and pressure on the limits for the propagation of flame in ether-air mixtures is quite material. The influence of the velocity of the gas-current was not examined throughout a sufficient range t o enable sound conclusions to be drawn as to its effect under manufacturing con-ditions but i t is fairly clear that a margin must be allowed for this factor when dealing with the limit results obtained. The presence of 1 per cent. of the peroxides of ether in ether-air mix-tures appears to have no appreciable effect on the lower limit for the propagation of flame and it is by no means likely that there would be sufficient peroxide present under practical conditions to affect the upper limit materially.Summary. The soap-bubble method described by McDavid (Zoc. cit.) gave for the ignition-temperature of ether-air mixtures results varying from 859" t o 1068O. The method seemed to be untrustworthy. 3 K* 1504 THE IGNITION OF ETHER-ALCOHOLAIR ETC. The other method used seemed to give the minimum temperature a t which the reaction in a combustible gas-mixture became self-supporting-called the sub-ignition-temperature. This temperature, which appears t o be the one required from a safety point of view, was 187O for ether-air mixtures in glass and varied from 187O t o about 500° for the different ether-alcohol-air mixtures used.It was about 500° for acetone-air mixtures. The presence of appreci-able quantities of metal in the vessels used lowered the sub-ignition-temperature. Decrease of pressure appeared to reduce the sub-ignition-temperature of a mixture but the presence of small quantities of glyceryl trinitrate or of diethyl peroxide had little effect on the sub-ignition-temperature of ether-air mixtures. The sub-ignition-temperature of such mixtures was lowered by the presence of ethyl hydrogen peroxide. The effect of slight velocities seemed to be to raise the sub-ignition-temperature of ether-air mixtures. When an exhausted vessel is quickly put into communication with a reservoir containing ether-air or carbon disulphide-air mixtures under specified conditions the gas can be ignited a t the ordinary temperature. This phenomenon has been termed shock ignition. The limits for the propagation of flame in mixtures of ether-alcohol-air and ether-acetone-air have been determined in 2.5 and 5 cm. tubes of glass and in 5 and 15 cm. tubes of iron. The extreme limits found were 1.73 and 23-30 per cent. for ether-air mixtures 4.16 and 18.95 per cent for alcohol-air mixtures and 2.88 and 12-40 per cent. for acetone-air mixtures. The upper limit for propagation in alcohol-air was determined a t 60°. Figures obtained with the 15 cm. iron tube often differed appreci-ably from those obtained with 5 cm. glass tubes. Le Chatelier’s rule was found to hold fairly well for ether-alcohol-air mixtures except for horizonkal and upward propaga-tion in the case of the upper limit. The only considerable devia-tion from the rule in the case of ether-acetone-air mixtures was observed for upward propagation and the upper limit. Increase of temperature was found to raise the upper limit for propagation in ether-air notably and reduction of pressure was found to narrow the limits. Increase in the velocity of the gas-mixture widened the limits materially. The presence of the per-oxides of ether scarcely affected the lower limit of propagation in ether-air but any considerable quantity raised the upper limit of such a mixture. It was found impossible t o ignite ether-alcohol-air mixtures by means of steel to steel emery to steel or pyrites to steel sparks bu THE CONDUCTIVITIES OF IODOANIL1"ESULPHONIC ACIDS. 1505 inflammation was readily obtained when using ferro-cerium t o steel sparks. Many of the properties of ether-air mixtures appear to be explained by the formation of a cool flame. Further work is contemplated on the phenomenon referred to as shock ignition. We desire to express our thanks to Messrs. Nobel's Explosives Co. Ltd. for whom the work was carried out and particularly to Mr. W. Rintoul Manager of the Research Section for kind per-mission to publish our results. We also wish to thank Mr. A. W. Sanderson for assistance in carrying out some of the experimental work. THE RESEARCH LABORATORIES, ARDEER FA~ORY STEVENSTON. [Received September 22nd 191 9.

ISSN:0368-1645    

DOI:10.1039/CT9191501462

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

THE CONDUCTIVITIES OF IODOANILINESULPHONIC ACIDS. 1505 CXXXIX.-The Conductivities of Iodoanilz'nesuiphonic Acids. By MARY BOYLE. No systematic study of the halogen-substituted derivatives of the anilineoulphonic acids seems to have been attempted. Eight out of the ten possible monochloro- about five of the monobromo- and three monoiodo-derivatives have been described by P. Fischer, Post Meyer Bahlmann etc. but in some cases the constitution is left uncertain and in most others there is merely a simple state-ment of the preparation and properties of individuals; owing to the incomplete character of the group no comparative study of either the chloro- bromo- and iodo-substituted derivatives or of the different members of a group of acids substituted by one par-ticular halogen has been possible.It was thought that it might be interesting to study one particular property throughout a com-plete series in order t o determine how the value of that property is affected by the position in the nucleus taken by the halogen relative to the two other groups present. The series chosen was that of the iodoanilinesulphonio acids and the property that of electrical conductivity. So far however it has not been found possible to prepare th 1506 BOYLE THE CONDUCTIVIT1;ES OF ten possible isomerides but the following eight, constitution are now known : of established NH, The series of chloroanilinesulphonic acids described by P Fischer, Meyer Claus Goslich Limpricht etc. corresponds closely with the above except that the chloro-analogue of I11 is unknown and that a 3-chloroaniline-2-sulphonic acid described by Post and Meyer has no counterpart up to the present among the iodine compounds.2-Iodoaniline-4-sulphonic acid (VII) was described in a patent by Kalle & Co. (D.R.-P. 129808) and its constitution established in 1909. 4-Iodoaniline-2-sulphonic acid (I) and 3-iodoaniline-4-sulphonic acid (VIII) were described by the author in 1909 (T, 95 1689, 1709). The others have been prepared from various nitroanilinesulphonic acids as described below. 5-ZodoaniZine-2-suZphonic acid (11) was obtained from p-nitro-aniline-m-sulphonic acid by treating it with iodine chloride remov-ing the amino-group and subsequently reducing the nitro-group. 6-lodoaniline-2-sulphonic acid (111) was prepared with more difficulty and small quantities only have been obtained.The p-nitroaniline-o-sulphonic acid described in 191 1 (T. 99 325) gave, when treated with iodine chloride an iodo-derivative for which only one configuration is possible. Reduction of the nitro-group gave a diaminosulphonic acid which by the loss of one amino IOD OANILINESULPHONIC ACIDS. 1507 group could yield two different iodoanilinesulphonic acids as figured below : Considerations of steric hindrance would suggest the first as the more probable reaction and that it does take place exclusively is proved by the conversion of the iodoanilinesulphonic acid into the well-known 2 3-di-iodobenzenesulphonic acid. 4-lodoaniline-3-sulphonic acid (IV) and 5-iodoaniline-3-sulphonic acid (V) were both obtained from p-nitroaniline-o-sulphonic acid by submitting it to the followiiig series of reactions: I I I= ' (IV.) 6-lodoar~iline-3-sulphonic acid (VI) was obt,aiiied by a similar series of reactions from o-nitroaniline-p-sulphonic acid.These acids resemble each other in appearance being well characterised colourless substances crystallising from water in needles. They vary somewhat in solubility in water the 6-iodo 1508 BOYLE THE CONDUCTIVITIES OF aniline-2-sulphonic acid being readily soluble most of the others giving N / 32-N/ 64-solutions and 3-iodoaniline-4-sulphonic acid dissolving sparingly. The latter acid crystallises with one molecule of water ; the rest are anhydrous. I n the experiments on conductivities the main difficulty ex-perienced was in the accurate determination of the strength of the acid solution.The unsubstituted anilinesulphonic acids were first investigated the pure acids being either (1) weighed out t o the required strength or (2) titrated with standard alkali and diluted to the required strength; the two methods were found to give identical results when special precautions in the standardisation of materials were taken. The numbers obtained in the case of the three anilinesulphonic acids are all higher than the corresponding numbers obtained by Ostwald (Zeitsch. physikal. Chem. 1889 3, 106) Winkelblech (ibid. 1901 36 546) White and Jones (Amer. Chem. J. 1909 42 520) and Wheeler and Jones (ibid. 1910 44, 159). It is to be noted however that these higher values give a better dissociation constant than do the earlier and lower ones.For example for aniline-p-sulphonic acid Ostwald gives a fiean K=5.81 x 10-4 showing a maximum variation of 0.8 x 10-5, Winkelblech a mean K=6*2 x 10-4 with a variation of 2.3 x 10-5, Wheeler and Jones a mean X,=6*55 x 10-4 and variation 1.7 x 10-5, and the author a mean K =7.05 x 10-4 with a variation of For aniline-o-sulphonic acid the mean value K = 4-29 x 10-3 as against Ostwald’s X = 3.21 x 10-3 and for aniline-m-sulphonic acid the value K =2.11 x 10-4 as against Ostwald’s K=1-85 x 10-4 and Wheeler and Jones’ K = 1.97 x The introduction of iodine into the nucleus increases the con-ductivities of the acids very considerably bringing them into the category of strong acids which do not obey Ostwald’s dilution law; in the case of some of the aniline-m-sulphonic acids only can a value of K whikh is even approximately constant be obtained.It is the position of the iodine relative to the amino-group which is the determining factor; whether in the meta- or para-position the effect in increasing the strength of the acid is approximately the same but when in the ortho-position the effect is very marked. The influence of the amino-group in diminishing the strength of the sulphonic acid is almost entirely neutralised by the ortho-substituted iodine and the iodoamino-sulphonic acid is found t o conduct to the same extent as benzenesulphonic acid itself. A com-parison of 6-iodoaniline-2-sulphonic acid with aniline-o-sulphonic acid and with benzenesulphonic acid shows this clearly.0.6 10-5. have been obtained IODOANILINESULPHONIC ACIDS. 1509 U. 32 64 128 256 512 1024 2048 A,. 109-5 144.1 183.4 2258 265-0 299.5 -A,. A,. - 321.07 340-0 -348-2 350.47 353.1 -356-7 356.38 357.8 359.03 - 354.22 The figures for benzenesulphonic acid are those given by Wight-man and Jones (Amer. Chem. J. 1911 46 56). The three following tables give the conductivities of the iodo-substituted acids side by side with those of the unsubst-ituted acid from which they are derived. Aniline-o-sulphonic A cid, I SO,H<-). SO,H <>. SO,H<>. so3d-\ \-/ H2N- H,N I H,NT H2* V . A,. A,. A,. A". 32 109.5 64 144.1 340.0 - -128 183.4 348.2 309.5 289.6 256 225.8 353- 1 333.2 320.9 512 265.0.356-7 348.7 341.6 1024 299.5 357.8 357.4 355.0 - - -A nilin e-m- sul ph on& A cid, I I 21. A,. 32 28.15 64 39.12 128 54.01 256 73-98 512 99-28 1024 131.5 K = 2.11 x 10-4. A,. A,. 242.3 115-3 286-4 149-5 319.3 191.2 342.2 235.5 358.2 279-9 - -K = 23.5 x 10-4 K X 104. A,. K X 104. - - -23.5 73.98 8.30 23.0 99.14 8-15 23.5 130-2 8.02 24-1 167-8 7.94 - 210.4 8.00 K = 8-08 x 10-4. Ostwald's value A =356 has been used in calculating the dis-sociation constants of the anilinesulphonic acids and h = 360 for calculating those of the iodoanilinesulphonic acids 1510 BOYLE THE CONDUCTIVITIES OF Aniline-p-st~1phon.ic Acid. SO,B/-\NH,. SO,H/-\NH,. SO,H/-\NH,. \-/ \-/ \.-/ I 0. A,. 32 49.73 64 68.30 128 92.54 256 122-9 512 159.4 1024 200.7 All.266-7 301.9 329.5 347.4 360.0 366.2 I -228.7 268.4 302.7 The same screening of the amino-group is brought about by other groups than iodine for example bromine the nitro-group, hydroxy-group etc. although none is quite so effective as iodine. From the literature on the subject of conductivities of acids the following data have been selected as bearing out what has been shown to be true of iodo-substituted acids. Bromoderivatives of Anilinesulphon@ ,4 cids. The acid containing bromine in the ortho-position with respect to the amino-group has a greater conductivity at all dilutions than the one with bromine in the para-position. Br U. 64.0 73.5 128.0 147.0 256.0 294.0 512.0 588.0 1024-0 1176.0 v.109.8 219-6 278.0 439.2 556-0 87864 11 12.0 A,. 70.0 92-3 122.5 157-4 197.5 ----A,. 224.4 351.8 276.5 296.3 312.6 I ----Br Br A,. A,. - 338 - 343 338 - 346 346 - 348 35 1 -- 1ODOANII;ENESULPHONLC ACIDS. 1511 Hydroxy-derivatives of Anilinesulphonic A cids. OH SO,H<>. SO3H<>0H. BH2 NH2 V. 64 128 256 612 1024 A". --16.0 22.4 31.3 All. 26.5 36.9 51-0 69.8 125.0 Here the same thing is observed although both acids have a smaller conductivity than the unsubstituted metanilic acid. AlLyl Derivatives of Anilinesulphonic Acids. The introduction of methyl into aniline-m-sulphonic acid gives results in harmony with the above.2). 32 64 128 256 512 1024 &I. 12-6 17-7 24.7 34.5 47.7 A A,. 42.3 56.8 77.2 104-6 137.5 -In the case of aniline-o-sulphonic acid however the position of the substituted group in the nucleus seems to make practically no difference to the conductivity value. CH, D. 32 64 128 256 512 1024 A". 53.9 73.7 99.5 131.4 169.1 210-9 A,. 51.0 69.9 94.6 125-2 162.5 1512 BOYLE THE CONDUCTIVITIES OF Balogen Deriuatiues of Anilimesulphortic Acids. Iodine is more effective than bromine in neutralising the effect This is seen from of the amino-group and bromine than chlorine. a consideration of the three following tables : 2). 64-0 73-5 128.0 147.0 256-0 294-0 512.0 588-0 1024.0 1176.0 V.64.0 128.0 256-0 512.0 1024.0 2). 64.0 71-9 128.0 143.8 256-0 287.6 512.0 575-2 1024.0 1150.0 2048.0 SO,H/-\I. \-/ NH, A,. 243.3 286-4 319.3 342.2 358.2 -----I A,. 7 3-98 99-14 130.2 167-8 210.4 c1 SO,H<>Cl NH2 A,. -130.0 158-4 189.2 227.9 268.5 ----&I. 224.4 251.8 276-5 296.3 312.6 -----Br SO~H/-\ . XH2 \-/ A,. 7 0 0 92.3 122-5 157-4 197.5 Br s O,H- r \ ~ r . \-/ N=2 A,. 262 289 313 329 340 --I -- IODOANILINESULPHONIC ACIDS. 1513 EXPERIMENTAL. Preparation of the Acids. 4-Iodoaniline-2-sulphonic acid was prepared from aniline-o-sulphonic acid according to the method previously described (T., 1909 95 1698).After repeated crystallisations the acid still possessed a faint violet tinge (Found C = 24.03 ; H = 1.99. Calc. : C = 24-07 ; H = 2-00 per cent.). Solubility.-One hundred grams of water dissolve 0.51 gram of the acid a t 2 5 O . 5-lodoaniline-2-sulphonic A cid .-The method of preparation consists in (a) introducing iodine into p-nitroaniline-m-sulphonic acid ( b ) displacing the amino-group by hydrogen ( c ) reducing the nitro-group. (a) Preparation of 6-lodo4+itroaniline-2-sulphonic A cid.-Fifteen grams of 4-nitroaniline-3-sulphonic acid prepared by Eger’s method from aniline-m-sulphonic acid (Ber. 1888 21 25Sl) were dissolved in a large volume of boiling water a little hydrochloric acid was added and 11.2 grams of iodine chloride were then passed into the solution which was kept a t 90-95O.Experiments were carried out at lower temperatures but the sparing solubility of the acid enabled only small quantities to be worked up a t a time and the yield was only inappreciably increased. The reddish-yellow solution after remaining for half an hour was evaporated to a very small bulk when the dark yellow acid separated on cooling. A yield of 20.4 grams amounting to 87 per cent. of the theoretical, was obtained. (b) Preparation of 4-lodo-2-nitrobenzene~ulphonic Acid.-Fifteen grams of the above acid were diazotised in sulphuric acid solution by means of 3 grams of sodium nitrite. The sparingly soluble diazo-compound was then boiled with alcohol under a reflux condenser and the dark-coloured residue after removing the alcohol was dissolved in water neutralised with sodium carbonate and boiled with animal charcoal; the yellow filtrate deposited on concentration long yellow needles which became opaque on exposure to air.The yield amounted to nearly 70 per cent. of the theoretical. (c) Preparation of 5-lodoaniline-2-sulphonic A cid .-The nitro-acid was reduced as usual with stannous chloride a t loo*. There was little apparent action the solution retaining its yellow colour, but when the yellow solid which was precipitated on cooling was dissolved in sodium carbonate a white amino-acid was obtaine 1514 BOYLE THE CJONDUCTIVITIES OF from this solution by adding concentrated acid. Proof of its struc-ture was obtained by replacing the amino-group by iodine and converting the di-iodobenzenesulphonic acid into a chloride melting a t 75O and identical with 2 4-di-iodobenzenesulphonyl chloride : C=24*01; E(=2*05.0.1341 gave 0-1181 CO and 0-0248 H,O. C,H,O,NIS requires C = 24.07 ; H = 2-00 per cent. Solubility.-One hundred grams of water contain 0.26 gram of acid at 25O. 6 -1od oaniline - 2-sulp h onic A cid . -6 -1od o-4-nit roaniline-2-sulphonic acid (T. 1911 99 330) was reduced with stannous chloride a t looo to 6-iodo-p-phenylenediamine-2-sulphonic acid which is a white, crystalline substance sparingly soluble in water. A small quantity (2.5 grams) was diazotised in the minimum amount of sulphuric acid by addipg 0.55 gram of sodium nitrite (theoretical amount for one amino-group is 0.53 gram); the dark yellow diazo-compound was then collected and boiled with alcohol.After evaporating off the alcohol and boiling the neutralised residue with animal char-coal the filtered solution and the amino-acid precipitated from it were still somewhat coloured. This amineacid has not yet been obtained in a colourless condition; it crystallises in pale brown needles from water in which it is rather readily soluble. Its con-version into 2 3-di-iodobenzenesulphonyl chloride melting a t 127O, confirmed its constitution : 0.1937 gave 0.1701 CO and 0.0370 H,O. C=23-95; H=2.11. C6€€,03NIS requires C = 24-07 ; H = 2.00 per cent. 4-lodoaniline-3-sulphonic Acid.-Nineteen grams of p-nitrd-aniline-o-sulphonic acid (T. 1911 99 324) were diazotised in sulphuric acid solution by 5.7 grams of sodium nitrite and the bright yellow diazo-compound was decomposed by potassium iodide.A voluminous yellow precipitate of potassium 2-iodo-5-nitrobenzene-sulphonate separated a t once from the hot solution and was collected and well washed with cold water. 'This salt was suspended in concentrated hydrochloric acid and reduced with stannous chloride the completion of the reduction being readily ascertained by the change in colour and in the appearance of the crystalline product. The amino-acid was purified as usual by precipitating it with concentrated acid from its solution in sodium carbonate. It separates from a concentrated aqueous solution in small spark-ling crystals from more dilute solutions in fine transparent needles. Its conversion into 2 5-di-iodobenzenesulphonyl chloride melting at 132O afforded proof of its constitution 'IODOAMIlINESULPHONIC ACIDS.1515 0.1871 gave 0.1644 CO and 0.0331 H20. C=23-96; H=1*97. C,H,O,NIS requires C = 24.07 ; H = 2.00 per cent. Solubility.-One hundred grams of water contain 1.36 grams of anhydrous acid at 25O. 5-Iodoaniline-3-sulphonic acid was prepared from pnitroaniline-o-sulphonic acid tuhrough 6-iodo-4-nitroaniline-2-sulphonic acid by (1) removing the amino-group (2) reducing the nitro-group. When the diazo-compound was boiled with alcohol nitrogen was evolved rapidly and after about forty-five minutes a clear pale yellow solution was obtained from which on concentration pale yellow crystals separated ; these were neutralised with sodium carbonate and the sodium salt was recrystallised.Sodium 3-iodo-5-nitro b enzenesulphonat e was dissolved in hydrochloric acid and reduced with stannous chloride a t looo ; precipitation of the amino-acid as a cream-coloured crystalline mass followed almost immedi-ately. The acid dissolved in alkali and reprecipitated by mineral acid was then repeatedly crystallised from hot water separating in fine white needIes : 0.1778 gave 0.1569 CO and 0.0326 H,O. C=24*07; H,=2*03. Cs;H,O,NIS requires C = 24-07 ; H = 2.00 per cent. Solubility.-One hundred grams of water dissolve 1-31 grams of anhydrous acid a t 25O. The constitution of the acid was established by replacing the amino-group by iodine and converting the resulting di-iodobenzene-sulphonic acid into 3 5-di-iodobenzenesulphonyl chloride which crystallised from ether in needles melting at 93O.6-lodoaniline-3-sulphonic A cicl.-0-Nitroaniline-p-sulphonic acid was prepared (1) by nitrating sulphanilic acid according t;o Nietzki's method (Ber. 1885 18 294) (2) by sulphonating o-nitro-aniline by Rardtung's method (Annalen 1881 206 96). After displacing the amino-group by iodine and subsequently reducing the nitro-group the iodoaminosulphonic acid was obtained as a grey powder which crystallised from a large bulk of water: 0.2075 gave 0.1833 CO and 0.0388 H,O. Solubility.-One hundred grams of water contain 0-48 gram of acid at 25O. 2-Iodoaniline-4-sulphonic acid was prepared as previously described (T. 1909 95 1693) (Found C=24.03; H=2*11. Calc. C=24.07; H=2*00 per cent.).C=24.09; H=2.07. C,H,O,NIS requires C = 24.07 ; H = 2.00 per cent 1516 BOYLX THB CONDbCTIVITBS Ol? SoZubiZity.-One hundred grams of water dissolve 2.07 grams of the anhydrous acid a t 25O. 3-Iodoaniline-4-sulphonic acid was prepared by reducing 2-iodo-4-nitrobenzenesulphonic acid (T. 1909 95 1708) by means of stannous chloride. The reduction proceeded rapidly on the water-bath and was complete in less than an hour. The iodoamino-acid, precipitated from its solution in alkali by concentrated mineral acid was recrystallised from water several times separating in fine transparent needles containing one molecule of wate? of crystallisation : 0-1861 gave 0.1552 CO and 0.0425 H,O. Solubility.-One hundred grams of water dissolve 0.194 gram of anhydrous acid a t 2 5 O .Conductivity experiments were carried out in Ostwald cells in a thermostat at 25O. An ordinary Wheatstone bridge carefully calibrated and standard resistances were employed. The con-ductivity water was obtained by distilling first with acid then with alkaline permanganate finally alone in the ordinary form of apparatus consisting of tin distilling flask block-tin condenser, and Jena-glass receiver. I n making the solution of the acid for conductivity measurements excess of the acid was shaken vigorously in a Jena-glass flask with conductivity water and allowed t o remain for some time. The solid was then filtered off and the filtrate titrated against standard sodium hydroxide of slightly less strength; the solution was then diluted to that strength.Standard flasks pipettes and burettes were used throughout. In the preparation of the standard solutions conductivity water was used throughout. N / 10-Sodium hydroxide was titrated against N / 10-hydrochloric acid which had previously been standard-ised by means of pure sodium carbonate and each solution was then diluted to N / 3 2 N/64 X/128 N/256 and titrations of one against the other were carried out in order that errors introduced by the hydrolysis of the indicator phenolphthalein a t such con-siderable dilutions should be obviated. The results of experiments carried out under these conditions agreed well with those obtained by weighing out the acid directly and dissolving it in the requisite amount of water. After one set of results had been obtained the acid was recrystallised and the conductivity again determined ; the recrystallisations and subsequent determination of conductivity were repeated until consecutive experiments gave identical results ; in this way the purity of the acid was guaranteed. In some cases, C=22-74; H=2.53. C,H,O,NIS,H,O requires C = 22.71 ; H = 2-52 per cent IODOANILINESULPHONIC ACIDS. 1517 ten crystallisations had t o be carried through before satisfactorily concordant results were obtained. Further experiments on the conductivities of the anilinesulphonic acids are being carried out and it is hoped that the resulta may shortly be ready for publication. I wish to express my thanks to Miss E. E. Field for valuable help given during the course of this investigation. ROYAL HOLLOWAY COLLEGE, ENGLEFIELD GREEN, SURREY. [Received October Sth 1919.

ISSN:0368-1645    

DOI:10.1039/CT9191501505

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

INDEX OF AUTHORS’ NAMES. TRANSACTIONS. 1919. A. Abram Harold Helling. See Thoinns Martht Lowry. Allmand Arthur John and Wilfrid Gwtav Polack the free energy of dilution of aqueous sodium chloride solutions 1020. Applebey Malcolm Pemival sodium hypochlorite 1106. Armstrong Edward Frankland and Thomas Percy Hilditch conversion of the simple sugars into their enolic and ethylene oxide forms 1410. Aston Francis WiZZiam a simple form of apparatus for estimating the oxygen content of air from the upper atmo-sphere 472. B. Barnea James Heclor obituary notice of 409. Barratt Sydney and Alan Francis Titley the catalytic reduction of hydrogen cyanide 902. Batep John Percy obituary notice of, 408. Baxter Robert Etginald and Robert George Fargher 1 :3-benzodiazole-arsinic acids and their reduction pro-ducts 1372.Bennett George Macdonald the nitra-tion of diphenylethylenediamine 576. Blount Bertram and James Harry Sequeira “blue john ” and other forms of fluorite 705. Bonafield William Robert mixtures of nitrogen peroxide and nitric acid 45. Boyd David Runcimnn and (Miss) Doris Feltham Thomas the velocities of combination of sodium derivatives of phenols with olefine oxides. Part II. 1239. Boyle (Miss) Mary t h e conductivities of iodoanilinesulphonic acids 1505. cxv. Briggs Sa?nuel Henry ClSffwd, chromatocobaltiammines 67. the theory of duplex a5nity 278. Burrows Qeorge Joseph the rate of hydrolysis of methyl acetate by hydro-chloric acid in water-acetone mixtures, 1230. Burrows George Joseph and Rustaxe Ebeneaer Turner the constitution of the nitroprussides.Part I. Conduc-tivity and cryoscopic measurements, 1429. C. Carpenter Charles WilZiam. See Hubert Frank Coward. Challenger Frederick. See Percy Paraday Frankland. Chapman David Leonard and William Job Jenkins the interaction of acetyl-ene and mercuric chloride 847. Chapman David Leonard and John Reginald Harvey Whiston the inter-action of chlorine and hydrogen ; the intlnence of mass 1264. Chatterjee Nihar Zanjan. See Rasik La2 Datta. Clewer Hubert FVilliam Bedley. See John Augustus Goodson. Cofman Victor the active substance in the iodination of phenols 1040. Coward Hu.bcrt Frank Charles William Carpenter and William Payman the dilution limits of inflammability of gaseous mixtures.Part 111. The lower limits of some mixed inflam-inable gases with air. Part IV. The upper liinits of some gases singly and mixed in air 27. Coward Eubcrt Frank and Stanley Pierce Wilson the eqiiilibrium between carbon hydrogen and methane 1380. D. Das Ananda Xisore and Brojendra iVath Ghosh condensation of deoxy-benzoin and aldehydes 817. 3 1520 INDEX OF AUTHORS. Das a d h a Kishen. See (Sir) Prufulla Chandra RQy. Datta Rasik Lal and Nihar Banjan Chatterjee the temperature of explo-sion for endothermic substances 1006. De Bajendralal polar and non-polar valency 127. Dean George trustworthiness of the halance over long periods of time, 826. Denham EiEnry George the sub-acetate and sub-sulphate of lead 109.the preparation of cadmium suboxide, 556. Denham Henry George. See also Stewart Byron Watkins. Dey Biman Bihari and Mahendra Nath Goswami J/-l:8-isonaphthoxaz-ones 531. Dick Charles William obituary notice of 408. Dick James Scott. See James Colpuhoun Irvine. Donnan Frederick George and Williarn Edward Garner equilibria. across a copper ferrocyanide and an amyl alcohol membrane 1313. Durrant Reginald Graham the inter-action of stannous and arsenious chlorides 134. E. Early Regimald George and Thomas Martin Lowry the properties of ammonium nitrate. Part I. The freezing point and transition-tempera-tures 1387. Evans Frederick Page. See Gilbert Thontas Morgan. Evens Eric Uoddrell. See Gilbert Thomas Morgan. Everest Arthur E’mest [in part with Harold Bogerson] the preparation of diacetonamine 588.F. Fargher Robert George substituted phenylarsinic acids and their reduction products and the estimation of arsenic in mch compounds 982. Fargher Bobert George and Frank Lee Pyman nitro- arylazo- and arnino-glyoxalines 217. the abnormal behaviour of glyoxaline-carboxylic esters and anilides to-wards diazoniuni salts 1015. See also Bobert Fargher Robert George. Ileginald Baxter. Fawsitt Charles Edward the freezing point of solutions with special reference to solutions containing several solutes 790. bhe use of freezing-point detormina-tions in quantitative analysis 801. Forater Marlin Onsbow and Ram Spinner studies in the camphane series. Part XXXVII. Aryl deriva-tives of imino- and amino-camphor, 889.Foster George Carey obituaiy notice of, 412. Fox Francis William. See John Addynzun Gardner. Frankland Percy Faraday Frederick Challenger and Noel Albert Nicholls the preparation of mono-methylamine from chloropicrin, 159. the preparation of nionomethyl-aniline 198. Frankland Percy Faraday and Frederic Horace Qarner the rotation dispersion of butyl heptyl and octyl tartrates, 636. Freak Gilbert Arthur the effect of dilution in electro-titrimetric analyses, 55. Q. Gardner John Addyman and Francis William Fox chloropicrin. Part I., Garner Frederic Horace. See Percy Faraday Frankland. Garner Wzlliam Edward. See Prt derick George Donnan. Qhosh Brojendra Nuth. See Ananda Kisore Das. Ghosh Praphulla Chandra curcumin, dyes derived from quinolinio acid, Gooason John Augwtus and Ei2tbe.l.t William Bentley Clewer examina-tion of the balk of Croton gubmga; isolation of 4-hydroxyhygric acid, 923.Qoswami Mahendra Sath.. See Bintan Bihari Dey. Gough William Eenry and Jocolyn Field Thorpe asymmetric replacement in the meta-series. Guha PrRfulla Chandra. See (Sir) Prafulla C’handra RBy. 1188. 292. 1102. Part I. 1155. H. Harris Joscph Walter the optically active neomethylhydrindamines 61 INDEX OF AUTHORS. 1521 Harrison Edward Rruitk obituary notice of 562. Haworth Walter Norman. and (Miss) Grace Oumminy Leitch the constitu-tion of the disaccharides. Part 111. Maltose 809. Heberlein Christian. See Robert Lud-Hepworth Harry the absorption spectra of the nitric esters of glycerol 840.the action of Grigiiard reagents on the esters of certain dicarboxylic acids 1203. Kewftt John. Theodore and Williani Jacob Jonee the estimation of the methoxyl group 193. Hickinbottom Wivred John. See Joseph Beilly. Higaon Geofrey Isherwood. See Roland Edgar Slade. Hilditch Thomas Percy. See Edward Frankland Armstrong. Einshelwood Cyril Normu?t the oxi-dation of phenol derivatives 1180. Hughes William the reaction botmeen sodium chloride solution and metallic magnesium 272. wig Mona. I. Ingold Christophr Kelk and Jocelyn Field Thorpe experiments on the elimination of the carbethoxyl group from tnutomeric systems. Part I. Derivatives of indene 143. the formation and stability of spi~o-compounds.Part 11. Bridged-spiro-compounds derived from cyclohexsne 320. Colqukozm and Janies Scott Diak the constitution of maltose ; a new example of degradation in the sugar goup 593. Irvine - Jums J. James Thonias Canipbell. See Eric Walker. Jeana James Hopwood t$c quantum theory and new theories of atomic structure 865. Jenkinn TVillium Job. See David Leonard Chapman. Jephcott Harry the physical constants of nicotine. Part I. Spwific rotatory power of nicotine in aqueous solution, 104. Jones David Charles. See Kewnedy Joseph Previtt Orton. Jones David Trevor gLy cergL methyl ether diljitrate (a-methylin c h i trate), 76. Jones William Jacob. See John Theo-dore Hewitt. K. Kam James. See James William ElcBain.Eemp William Joel obituary notice of 427. King Albert Theodore the production of methyl ethyl ketone from n-butyl alcohol 1404. King Rarold the resolution of hyoscine and its components tropic acid and oscine 476. the stereochemistry of hyoscine 974. Enox Joseph and (Miss.) Marion Brock Richards the basic properties of oxygen in organic acids and phenols and the quadrivalency of oxygen 508. Enox Joseph and (Miss) Helen Beid Will the basic properties of phenanthraquinone 850. the solubility of silver acetate in acetic acid and of silver propionate in propionic acid 853. Eon George Armand Robert and Jocelp Field Thorps. I. The forma-tion and reactions of imino-corn-pounds. Part XIX. The chemistry of the cyanoacetamide and Guareschi condensations 686.Krizewsky Jacob and Eustace Ebenezer Turner formation of diphenyl by the action of cupric salts on organo-metallic compounds of magnesium, 559. L. Laing (Miss) Mary Evelyn. See Jam8 Lapworth Arthur and &ank AEBert Leitch (icliss) Grace Cum?niny. See Lewia Samuel Judd a new sector Lewis WiZliam Cudntore McCicElaqh, studies in catalysis. Part X. The applicability of the radiation hypo-thesis to heterogeneous reactions, 182. studies in catalysis. Part 31. The Le Chatelier-Braun principle from the point of view of the radiation h pothesis 710. stuAeu in catalysis. Part HI. Cat&-lytic criteria and the radiation hypo-thesis 1360. William MoBain. Royle capsaicin. Part I. 1109. Wa E ter Normun Eawor t h , spectrophotometer 312 1522 INDEX OF AUTHOR& Lowry Thomas Martin and Harold Helling Abram the rotatory dispersive power of organic compounds.Part IX. Simple rotatory dispersion in the terpene series 300. Lowry Thomas Martin. See also Reginald George Early, Lnmsden John Scott criteria of the degree of purity of commercial toluene, 1366. Laptan Sydney obituary notice of, 430. M. McArthar Donald Neil and AEfred Walter Stewart a new photographic phenomenon 973. XcBain Ja.mfx William and James Eam the effect of salts on the vapour pressure and degree of dissociation of acetic acid in aolution; an experi-mental refutation of the hypothesis that neutral salts increase the dissocia-tion constants of weak acids and bases, 1332. XcBain Ja.mcs William (Mhs) Mary Evelyn Lsing and Alan Francis Titley colloidal electrolytes soap solutions as a type 1279.McBain James William and (Miss) Millicent Taylor the degree of hydra-tion of the particles which form the structural basis of soax curd deter-mined in experiments on sorption and salting out 1300. McKenzie Alexander and John Kerfoot Wood the isomeric tropic acids 828. XcKenzie Alexander and Eenry Wren, catalytic racemisation of ethyl I-man-delate 602. Manning Rodger James and lllaximilian Nierenstein the tannin of the Cana-dian hemlock ( Tsuga canadensis, Carr.) 662. Xartineau George obituary notice of, 434. Mason Walter and Richard Vernon Wheeler the propagation of flame in mixtures of acetylene and air 578. Maxted Edward Bradford the syn-thesis of ammonia at high tempera-tures.Part III. 113. the influence of hydrogen sulphide on the occlusion of hydrogen by palla-dium 1050. Mazumder Jatindra Kumar. See Bawa Kartar Singh. litter Praficlla Chanclra and Atan-endra Nath Sen action of phenyl-hydraziiie on phthalaldehydic and phthalonic acids phenyl-hydrazo-and azo-phtlialide 1145. Xond Robert Ludwig and Christian Heberlein the chemietry of Burgundy mixtures 908. Morgan Gilbert Thomas and Frederick Page Evans 8-uaphthylme thylamine, 1140. Morgan Gilbert !T~O~IMGS and Eric Dod-drell Evens the constitution of in-ternal diazo-oxides (diazophcnols). Part II. 1126. Morgan John David the ignition of explosive gases by electric sparks 94. Mukherjee Jiiamndra Nath and Na-gendra Nath Sen coagulation of metal sulphide hydrosols.Part I. Influ-ence of distance between the particles of a sol on its stability; anomalous protective action of dissolved hydrogen sulphide 461. N. Nicholls Noel Albert. See Percy Para-clay FrankIand. Nicholson John William emission spectra and atomic structure 855. Nierenstein Maximiliccn the tannin of the colouring matter of the red pea Nierenstein Jfmimilian. See also Rodger James Manning. Norman George Marshall the formation of diazoamino-compounds from B-naphthylamine 673. the knopper gall 1174. gall 1328. 0. O’Connor EdmzLnd Arthur. See A lbert Cherb ury David Bive tt. Orton Kennedy Joseph Previtk and David Chmrles Jonem the critical solution temperatnre of a ternary mixture as a criterion of purity of toluene 1055.the temperature of critical solution of a ternary mixture as a criterion of purity 0-f n-butyl alcohol ; the pre-paration of pure n-butyl alcohol, 1194. P. Payman William the propagation of flame in complex gaseous mixtures. Part I. Limit mixtures and the uniform movement of flame in such mixtures 1436. the propagation of dame in complex gaseous mixtures. Part 11. The uniform movement of flame in mix-tures of air with paraffin hydro-carbons 1446 INDEX OF AUTEORS. 1523 Payman William the propagation of flarrie in complex gaseous mixtures. Part 111. The uniform movement of flame in mixtures of air with mixtures of methane hydrogen and carbon monoxide and with industrial inflam-mable gases 1454.Payman William and Bichard Vernon Wheeler the propzgation of flame through tubes of small diameter. Part II; 36. Payman William. See also Hubert Frank Coward. Pedler (Sir) Alcxaider obituary notice of 436. Perkin William. Henry iun. crypto-pine. Part II. 713. Perkin William ITenry jun. and flobert Robinson harniine and harnial-me. Polack Wilfrid Qustav. See Arthur John Allmand. Pope (Siy) William Jackson presi-dential address 397. Price Tudor WiEliams the vapour pressures and densities of mixtures of acetone and methyl ethyl ketone, 1116. the decomposition of carbamide in the presence of nitric acid 1354. Price Tudor WiEZiams. See also Albert Greville White. Prideaux Ed?nund Brydges €&ud?iaZl, the effect of sea-salt on the pressure of carbon dioxide and alkalinity of natural waters 1223.Pyman Fyank Lee the alkaloids of Ilolarrhena congolensis Stap f. 163. meta-substituted aromatic selenium compounds 166. Pyman Frank Lee. See also Robert Parts 111. and IV. 933 967. George Fargher. E. Rakshit Jitendra Nath. porphyroxine, RBy (Sir) Praftilla Chundra mercury mercaptide nitrites and their reaction with the alkyl iodides. Part TI. Chain compounds of sulphur 548. interaction of mercuric and cupric chlorides respectively and the mer-captans and potential mercaptans, 871. EBy (Sir) Prafulla Chaiulra and Prafdla Chandra Quha mercury mer-captide nitrites and their reaction with the alkyl iodides. Parts IV. V. and VII. Chain compounds of sulpliur, 261 541 1148.455. ails (Sir) Prafulla Chundra Prafulla Chandra Quha and Radha Kishen Dam reaction of the potassium salts of 2-thiol-5-thio-4-phenyl-4:5-dihgdro-1 :3 :4-thiodiazole and 2:5-dithiol-1:3:4-thiodiazole with halogenated organic compounds 1308. Ray (8ir) Prafulla C?iandra and Prafullcc Kzmar Sen niercuric sulph-oxychloride 552. Reilly Joseph and CVilfred John Hickinbottom the n-butylarylamines. Part 111. Constitution of the nitro-derivative8 of n-butyl-ptoluidine 175. Remington Joseph Price obituary notice of 438. Report of the Council 384. Report of the International Committee on Atomic Weights 879. Richards (Miss) Marioqz. Brock. See Joseph Knox. Xideal Eric Keiyhtley the selective conibustion of carbon monoxide in hydrogen 993.Rivett Albert Cher6urzJ David and Edmund Arthur O’Connor soiiie ter-nary systems containing alkali oxalates and water 1346. Robertson Philip Wilfred the melting points of the substituted amides of the nortrial fatty acids 1210. Robinson Robert. See William Henry Perkin jun. Rogerson Hctrold. See Arthicr Ernest Everest. Royle Frank Albert. See Arthur Lapworth. s. Schloesing Jean Jacques Thkophile, Sen Jnanendra Nath. See Prafulla Sen Nagendm Nath. See Jfinnendra Sen Prqfiilla Kwmar. See (Sir) Prufdln Senier AZfred obituary notice of 447. Sequeira James Hayry. See Bertram Singh Bawa Kartay and Jatindra Kumar Yazumder studies on the dependence of optical rotatory power on chemical constitution. Part I. Position-isomeribm and optical activity of naphthyliminocaniphors and derivatives of pheuylimino-camphor 566.condensation of deoxybenzoin with aromatic aldehydes 821. obituary notice of 440. Chandra Pitter. Nath Mukherjee. Chaidra RPy. El oun t 1524 INDEX OF 4UTHORS. Slade Roland Edgar and Geoffey Islmwood Higson equilibria in the reduction of oxides by carbon 205. the dissociation pressures of sons nitrides 215. Soddy Frederick tlie conception of the chemical element as enlarged by the study of radioactive change 1. Spinner Haw. See Martin Onslow Fore ter. Stewart Alfred Walter. See Donald Neil McArthnr. T. Taylor Charles Bomers the presence of aconitic acid in sugar-cane juice and a new reaction for the detection of the acid 886. Taylor (Miss) Millicent.See Jantes William PcBain. Taherniac Joscph thiocyanoacetono and its derivatives awl isornerides 1071. an automatic extraction apparatus, 1090. Thomas (Miu) Dmis Feltham. See David h?ultcimun Boyd. Thorpe Jocelyn Field the chemistry of the glutaconic acids. Part XI. The occurrence of 1:3-addition to the normal form 679. Thorp Jocelyn Field. See also Willium Henry Qoagh Christopher Kelk Ingold, and George Armad Robert Kon. Tiderwell Frederick Vincent and Richard Yernon Wheeler a chemical investi-gntion of hnnded bitnininous coal; studies in the composition of coal, 619. the oxidation of coal 895. Tingle John Bishop obituary notice of, 453. Titley Alan FranCiS. See Sgdney Barratt and James William McBain. Turner Eustacc Ebenezer.See George Joseph B ~ O W B and Jmob Krisewsky, U. Usher Francis Lawry and Ramaven-katasubbier Venkateewaran the po-tential of a nitrogen electrode 613. V. Venkateewaran Ramvenkatasvbbier. See Francis LawTy Usher. W. Walker Eric and Thomas Cmnpbell James molecular refractivity of cin-namic acid derivatives 1243. Watkins &wart Byron and Henry George Denham auto-complexes in solutions of cupric chloride and cuyric bromide 1269. Werner Emil AIphonse the preparation of butylnmiue and of it-dibutyl-amine ; the separation of aliphatic amines by partial neutralisation, 1013. the constitution of carbamides Part IX. Tho interaction of nitrous acid and mono-snbstituted urea8 ; the preparation of diazomethane diazo-ethane diazo-n-butane and diazo-isopentane from the respective nitrosoureas 1093.the constitution of carbamides. Part X. The behaviour of urea and of thiourea towards diazomethane and diazoethane respectively ; the oxi-dation of thiourea by potassiuni permanganate 1168. Wheeler Richard Vernon the inflani-mation of mixtures of ethane and air in a closed vessel the effects of turbulence 81. Wheeler Riclrard Vernon. See also Walter Maeon William Payman and Frederick Vincent Tideswell. Whiaton Jolm h'eyinald Harvey. See David Leonard Chapman. White Albert Gyeville and Tudor Tilliams Price the determination of ignition-temperatures by the soap-bubble method 1248. the ignition of ether-alcohol-air and acetone-air mixtures in contact with heated surfaces 1462. Will (Miss) Helen Reid. See Joseph Wilson Stanley Pierce. See Hubert Wood, John Kerfoot. See Alexander Wren Henry. See Alexander McKeuzie. Wright Robert the effect of some simple electrolytes ou the temperature of maximum density of water 119. niolecular-weight determination by direct measurement of the lowering of the vapour pressure of solutions, 1165. &ox. Frank Coward. YdcKenzie

ISSN:0368-1645    

DOI:10.1039/CT9191501519

出版商:RSC    

年代:1919

数据来源: RSC

摘要:

INDEX OF SUBJECTS. TRANSACTIONS. 1919. Single organic compounds of know11 empirical formula will be found in the Formula Index p. 1530. A. Acids aliphatic melting points of sub-stituted amides of (ROBERTSON), 1210. dicarboxylic esters of action of Grig-nard reagents on ( HEPWORTH), 1203. orgmic basic properties of oxygen in (KNOX and RICHARDS) 508. -Teak effect of neutral salts on the dissociation of (MCBAIN and KAM), 1332. Aconitic acid C6H606. Address presidential .(POPE) 397. Afflnity duplex theory of (BRIQGS), Alacreatine C,H,ON,. Aldehydes condensation of deoxybenzoin with (DAS and GHOSH) 817; (SLNGH and MAZUMDER) 821. Alkaloids from Holarrhe?ta congolensis (PYMAN) 163. Alkyl iodides reactionis of mercury mercaptide nitrites with (RAY and GUHA) 261 541 1148 ; (RAY) 548.Amides acid aliphatic substituted melt-ing points of (ROBERTSON) 1210. Amines separation of (WERNER) 1010. Ammonia flyntliesis of a t high tempera-tures (MAXTED) 113. Ammonium nitrate freezing point and trailsition tempt~atures of (EARLY and LOWRY) 1387. Analyais electro-volumetric effect of dilution in (FREAK) 55. quantitative use of freezing-poin t de-terminations in (FAWSITT) 801. Arsenious chlnride reaction between stannous clilnride and (DURILLN'I'), 154. Arsenic estimation of in substituted phenylarsinic acids (FAROHER) 982. 278. Annual Qsneral Xeoting 384. Arsenio :-Atmoepheric air propagation of flame i n mixtures of acetylene and (MASON arid WHEELER) 578. ignition of mixtures of with rtlcol~ol and ether and with acetoiie (WHITE aiid PRICE) 1462.ignition of mixtures of ethane and (WHEELER) 81. apparatus for estimation of oxygen in (ASTON) 472. Atomic structure and emission spectra and t h e quantum theory (JEANS), moights report of the International (NICHOLBON) 865. 865. Committee on 879. table of 885. Atrolactinic acid C,H,,O,. Atropic acid CoH80,. Azo-colouring matters (MORGAN and EVENS) 1138 ; (MORGAN and EVAKS), 1143. B. Balance trustworthiness of over long periods of time (DEAN) 826. Balance sheets of the Chemical Society and of the Research Fund. See Annual General Meeting 384. Bases weak effect of neutral salts on the dissociation of (MCBAIN and KAM), 1332. Benzene ring asymmetric substitution in (GOFGH ant1 THORPE) 1155.iso-$-Berberidene C,,H,oO,. Betonicine C,HI,O,N. " Blue John " (BLOUNT and SEQUEIRA), Burgundy mixtures chemistry of (MOND n-Butylarylaminee (REILLY and HICK-705. aud HEBEKLEIN) 908. INROTTOM) 175 1526 INDEX OF SUBJECTS. C. Cadmium suboxide preparation of (DEN-HAM) 556. Camphane series studies in (FORSTER and SPINNER) 889. Capaaicin CI8H2,O,N. Carbamides constitution of (WERNER), Carbon equilibrium in the system, methane hydrogen and (COWARD and WILSON) 1380. kinetics of the reduction of metallic oxides by (SLADE and HIGSON) 205. Carbon monoxide combustion of in hydrogen (RIDEAL) 993. dioxide pressure of in sea water (PRIDEAUX) 1223. Carbonatopentamminecobaltic nitrate, preparation of (BRIQM) 75. Catalysis studies in (LEWIS) 182 710, 1360.Chemical constitution and optical rota-tory power (SINGH and MAZUMDER), 566. reactivity quantum radiation hypo-thesis of and the Le Chatelier-Braun principle (LEWIS) 710. Chemistry in the national service (POPE), 397. Chlorine interaction of hydrogen and (CHAPMAN and WHISTON) 1264. Chloropicrin COINCl,. Chromatoaquotriamminecobaltic cli-chromate (BRIGGS) 75. Chromatocobaltiammines ( EKIGGS) 67. Chromatohydroxy triamminecobalt (BRIGGS) 74. * Chromatopentamminecobaltic aalts (BRIGQS) 69. Chromatotetramminecobaltic salts (BRIGGS) 72. Cinnamic acid derivatives molecular refractivity of (WALKER and JAMES), 1243. Coagulation of hydrosols (MUKHERJEF. and SEN) 461. Coal composition of (TIDESWELL and oxidation of (TIDESWELL and WHEEL-Colloidal electroIytes (MCBAIN LAING, and TITLEY) 1279.Colouring mattere from quinolinic acid (GHOSH) 1102. See also Dryophantin. spiro-Compounds formation and sta-bility of (INGOLD and THORPE) 321. Conessine C2,H4,N2. Copper sulphate and sodium carbonate, chemistry of mixtures of (MOYD and HEBERLEIN) 908. 1093 1168. WHEELER) 619. ER) 895. Copper :-Cupric bromide and chloride complex compounds in solutions of (WAT-KINS and DENHAM) 1269. Cupric chloride action of with mer-captans and thioamides(Ril~),871. salts action of magnesium organic compounds with (KRIZEWSKY and TURNER) 559. Critical aolution temperature of ternary mixtures (ORTON and JONES) 1055. Crotom gubouga constituents of the bark of (GOODSON and CLEWER) 923.Cryptopidene C,oH2004. Cryptopine C, H 230,N. Curcumin C,,H,006. Copper organic compounds :-D. Diazonium salts action of glyoxaline-cnrboxylic esters and anilides with (PARGHER and PYMAN) 1015. Diazo-oxider internal constitution of (MORGAN and EVENS) 1126. Diazophenols. See Diazo-oxides. Diffusion of Holutions across membranes of amyl alcohol and copper ferro-cyanide (DONNAN and GARNER), 1313. Dimethylrhodim C,H,ONS. 2:&Dirnethylthien C6H& Disaccharides constitution of ( BA-WORTH and LEITCH) 809. Dispersion rotatory of organic com-pounds (LOWRY and ABRAM) 300. Di thiaeylsmine C8H,N,S2. Dryophantin Cz3HZ8Ol6’ E. Electrode nitrogen potential of (USHER and VENKATESWARAN) 613. Electrolytes colloidal. See Colloidal.Elements chemical and radioactive change (SODDY) 1. Equilibrium of solutions between membranes of amyl alcohol and copper ferrocyanide (DONNAN and GARNER) 1313. Explosion temperatures of of endo-thermic substances (DATTA and CHATTERJEE) 1006. Extraction apparatus automatic (TCHERNIAC) 1090. F. Flame propagation of in gaseous mix-tures (COWARD CARPENTER and PAY-MAN) 27 ; (PAYMAN and WHEELER), 36 ; (WHITE and PRICE) 1248 1462 ; (PAYMAK) 1436 1446 1454 INDEX OF SUBJECTS. 1527 Flame propagation of in mixtures of acetylene and air (MASON and WHEELER) 578. propagation of in mixtures of ethane and air (WHEELER) 81. Fluorite. See Fluorspar. Fluorspar (BLOUNT and SEQUEIRA), Freezing point of solutions (FAWSITT), Freezing-point determinations use of, 705.790. in analysis (FAWSITT) 801. Gi. Galls. See Knopper and Pea galls. Gaaes ignition of rnixtures of (COWARD, CARPENTER and PAYMAN) 27 ; (PAYMAN and WHEELER) 36; (MASON and WHEELER) 578; (WHITE and PRICE) 1248 1462; (PAYMAN) 1436 1446 1454. explosive electrical ignition of (MORGAN) 94. Glutaconic acids chetnistry of (THORPE) 679. Glyoxalinecarboxylic acids anilides and esters action of with diazoninm salts (FARGHER and PYMAN) 1015. Grignard reagenta acticjn of with sters of dicarbosylic acids (HEP-WOETR) 1203. H. Harma!ine C,,H,,ON,. Harman C,,H,,N,. Harmine C1,H,,0N2. Hemlock Canadian. See Tsuga carts-densis. Hexo8es coriversion of into their enolic and ethylene oxide forms (ABM-STRONG acd HILDITCH) 1410.Holarrhena congolensis alkaloids of (PYMAX) 163. Holarrbenine Cz4H asON 2. Hydrogen equilibiium in the system : carbon methane and (COWARD and influence of hydrogen sulphide on the absorption of by palladium (MAXTED) 1050. conibustion of carbon monoxide in (RIDEAL) 993. interaction of chlorine and (CHAPMAX and WHITE) 1264. Hydrosols coagulation of (MUKHERJEE and SEN). 461. WILSON) 1380. Rygrio acid 4-hydroxy- C,H,,O,N. Hyoscine C17H,,04N. I. Ignition of gaseous mixtures (COWARD, CARPENTER and PAYMAN) 27 ; (PAYMAN and WHEELEB) 36; (WHITE and PRICE) 1248 1462 ; (PAYMAN) 1436 1446 1454. of explosive gases by electric sparks (MORGAN) 94. of mixtures of acetylene and air (MASON and WHEELER) 578. of mixtures of ethane and.air (WHEELER) 81. Imino-compoande formation and re-actions of (KON and THORPE) 686. Indene derivatives ( INGOLD and THORPE) 143. K. Ketones condensation of with cyano-acetamide and with ethyl cynno-acetate (KON and TIIORPE) 686. Knoppsr galls tannin from (NIEREN-STEIN) 1174. L. Lead subsulphate (DRNHAM) 109. Lectures delivered before the Chemical Society (SODDY) 1 ; (NICHOLSON), 855; (JEANS) 865. M. Magnesium reaction between sodium chloride solutions and (HUGHES) 272. IIbagneaium organic compounds action of cupric salts on (KRIZEWSKY and TURNER) 559. Xaltose C,,HZ20,,. Mercaptans action of with cupric and mercuric chlorides (RAY) 871. compounds of mercuric nitrite with, and their reactions with alkyl iodides (RAY and GUHA) 261 541 1148; (RAY) 548.Mercury :-Xercuric chloride action of acetylene with (CHAPMAN and JENKINS), 847. sulphoxychloride (RAP and SEN), 552. Mercuric chloride action of with mereaptans and thioamides (RAY), 871. iodide reactionsof with ethyl sulph-ide and alkyl iodides (RAY and GUHA) 1154. Mercury mercaptide nitrites reactions of with alkyl iodides (RAY and GUEA) 26 541 1148; (RAP) 548. Mercury organio compounds : 1528 INDEX OF SUBJECTS. Metallic oxides kinetics of the reduction of by carbon (SLADE and HIGSON), 205. sulphides coagulation of hydrosols of ( MUKHERJEE and SEN) 461. Meteloidine C,,H,,O,N. Methoxyl groupr estimation of (HEWITT and JONES) 193. a- and 8-lethylrhodim C,H,ONS. Mixtures ternary critical solution temperature of (ORTON and JOHES), 1055.Molecular refractivity of cinnamic acid derivatives (WALKER and JAMES), 1243. N. ~-1:8-isoNaphthoxazones C1,H70,N. Niootine CloH,,N2. Nitrides dissociation pressures of (SLADE and HICISON) 215. Nitrogen peroxide or tetroxide (nitric p e r d d e ) mutual solubility of nitric acid and ( BOUSFIELD) 45. Nitric acid mutnal solubility of nitrogen peroxide and (BOUSFIELD), 45. Nitrogen eleotrode. See Electrode. Nitropruasiderr constitution and pro-perties of (BuRRows and TURNER), 1429. 0. Obituary noticea :-James Hector Barnes 409. John Percy Ratey 408. Charles William Dick 409. George Carey Foster 412. Edward Frank Harrison 562. William Joel Kemp 427. Sydney Lupton 430. George Martineau 434. Sir Alexander Pedler 436.Joseph Price Remington 438. Jean Jacques Theophile Schloesing, Alfred Senier 446. John Bishop Tingle 453. Oleflne oxides velocity of combination of sodium derivatives of phenols with (BOYD and THOMAS) 1239. Optical rotatory power and chemical constitution (SINGH and MAZUMDER), 566. Organic compounds rotatory dispersion oP (LOWRY and ABRAM) 300. Oscine C8HI30,N. Oxygen basic properties of in organic acids and phenols and its quadri-valency (KNOX and RICHARDS) 508. 440. Oxygen apparatus for estimation of in air (A~ToN) 472. P. Palladium influence of hydrogen snlph-ide on the absorption of hydrogen by ( MAXTED) 1050. Pea galls red colouring matter of (XIERENRTEIN) 1328. Phenolo basic properties of oxygen in iotlination of (COFMAN) 1040.sodium derivatives velocity of combi-nation of with olefine oxides (BOYD and THOMAS) 1239. Phenol derivatives oxidation of ( HIN-SHELWOOD) 1180. Phenylarsinic acids substituted estima-tion of arsenic in ( FARGHER) 982. Photography new phenomenon in (hlCARrHUR and STEWART) 973. Porphyroxine C,,H,,O,N. Purity determination of by the critical solution temperature (OKTON and JONES) 1194. (KNOX aiid RICHARDS) 508. Q. Quantum theory and atomic structure Quin~linanil,C,~H,O~N~. (JEANS) 865. B. Radiation hypothesis application of to Radioactive change and the conception catalysis (LEWIS) 182 710 1360. of chemical elements (SODDY) 1. S. Sea water See under Water. Selenium organic compounds aromatic (PYMAN) 166.Soap solutions as colloidal electrolytes (MCBAIN LAINU and TITLEY) 1279. Soaps hydration of the particles form-ing the curd of (MCBAIN and TAYLOR), 1300. Sodium carbonate and copper sulphate, chemistry of mixtures of (MOND and HEBERLEIN) 908. chloride free energy of dilution of aqueous solutions of (ALLMAND and POLACK) 1020. reaction between solutions of and metallic magnesium (HUGHES), 272. hypochlorite (APPLEBEY) 1106 INDEX OF SUBJECTS. 1529 Solutions freezing point of ( FAWSITT), 790. diffiision and equilibrium of between membranes of amyl alcohol and copper ferrocyanide (DONNAN and GARNER) 1313. Spectra elnission and the structure of Spectrophotometer new sector (LEWIS), Spiro-compoundrr. See under Compounds. Stannous ealts.See under Tin. Substitution asymmetric in tho benzene ring (GOUGH and THORPE) 1155. Sugars conversion of into their enolic and ethylene oxide forms (ARMSTRONG and HILDITCH) 1410. Sngar-cane aconitic acid in the juice of (TAYLOR) 886. Sulphides. See Metallic sulphides. atoms (NICHOLSON) 855. 312. T. Tannin from hemlock preparation and reactions of (MANNING and NIEREN-STEIN) 665. from knopper galls (NIERENSTEIN), 1174. Tautomeric compounds elimination of the carbethoxyl group from (INGOLD and THORPE) 143. Terpene derivatives rotatory dispersion of (LOWRY and ABRAM) 300. Thioamides action of with cupric and mercuric chlorides (RAY) 876. Tin :-Stannous chloride reaction between arsenious chloride and (DUERANT), 134. Trichromato-octamminedicobalt Tropic acid C,H,,O,. Tsuga eartadensis (hemlock) tannin o i Teuginic acid broino- C,H70,Br. Turicine C7H,,0,N. (BRIGQS) 73. (MPNNING and NIERENSTEIN) 662. V. Valency polar and non-polar (DE) 127. W. Water effect of electrolytes on the temperature of rnaxiinii~? density of (WRIGHT) 119. Sea water efrect of sea-salt on the pressure of carbon dioxide and alkalinity in (PRIDEAUX) 1223. Weights moleonlar determination of, by measurement of vapour pressure loirering (WRIGHT) 1165

ISSN:0368-1645    

DOI:10.1039/CT9191501525

出版商:RSC    

年代:1919

数据来源: RSC