CAPTAIN REYNOLDS ON PROPYLENE XV.-On ‘‘ Propylene,” a new Hydrocarbon of the series C H,. By CAPTAINJOHNW. REYNOLDS,F.C.S. The formula C H, represents a numerous group of bodies con- taining an equal number of equivalents of carbon and hydrogen of which the well-known olefiant gas C H, may be taken as the type* For many years this latter stood alone till Mr. Faraday in a research upon compressed oil-gas published by the Royal Society in 1825,* showed the existence of another substance of like percentage- composition but distinguished from it by the number of carbon and hydrogen equivalents condensed into the same space ; since that time the progress of science has made us acquainted with a numerous series of similar bodies. The dehydration of the alcohols C Hn+20, or C H, 2 HO has been the chief but by no means the only source of these hydro-carbons which are also formed in several processes of destructive distillation and in the metamorphoses of various compounds con-nected with the alcohols.The consequence of this diversity of origin and the propensity of each alcohol to give rise in addition to a hydrocarbon containing the same number of carbon equivalents as itself to several rnetameric bodies is that the series C H exceeds in number that of the alcohols C H,+ O, though it does not reach to that of the acids C H 0,,with which both are associated. * Phil. Trans. 1825. CAPTAIN REYNOLDS The result of the experiments detailed in the following pages has been to supply a term hitherto wanting in the series the position of which will be best understood by inspection of the subjoined table in which all the members of the series C H, at present known are given together with the corresponding alcohols so far as we are acquainted with them.Methyl-alcohol . . C H4 0 Methylene . c H, Ethylene . Ethyl-alcohol C H6 0,{Bthene . Olefiant gas . YY 3 Y , Yt I) Butylene 11 9) , { Ditetryl . . Amyl-alcohol . . C,,H,,O Amylene . . . C, H, Caproylene , YY 2 1) ,> IY { Naphthene *) C16 a 59 Paramylene . . C H, J3 fl $1 J> Jt J Cetylene . Cetyl-alcohol . + . { Cetene *... C32H3402 19 97 9 ,? , Metamylene . C, H,o f> 1 ,J >Y 7 ..> Cerotyl-alcohol .Cerotylene . Cerotin . . . . Cerotenc . . . >Y , Y ¶J > $Y } c 60 H 0 Melissyl-alcohol . . Melissylene . Melissin . 69 2 { Melene . . In this table are not included a number of isomeric hydrocarbons said to be contained in coal-tar naptha and present in the various kinds of petroleum and also obtained by the distillation of the fatty acids because their position on the scale has not been sufficiently well established ; even the table contains some terms concerning which doubts still exist. Methylene* has been obtained only once by Dumas and Peligot and as appears from their account not in a state of absolute purity. * Ann Ch.Phgs. [2] LVLII 1. ON PROPYLENE. 113 Ethylene ethene or olefiant gas is obtained as is well known by the de-hydration of ordinary alcohol.The alcohol corresponding to the next term in the table C HS is not known but the hydrocarbon itself was obtained originally by Faraday,s as before mentioned from the liquid condensed from oil-gas; the same body according to Bouchardat,? appears to exist among the products of the dry distillation of caoutchouc; and Kolbel has also lately obtained it as a product of the decomposition of valeric acid by the battery. Amylene has been studied by Balard,$ who obtained it by the action of chloride of zinc upon amyl-alcohol or fusel-oil.11 The reaction with chloride of zinc gives rise also to the formation of paramylene originally obtained by Cahours,v in the corresponding prc cess with phosphoric acid and metamylene whose formulze have bet n controlled by the determination of the density of their vapours.(hproylene is one of the hydrocarbons obtained by Fremy,** in the destmstive distillation of several fatty acids ; it was originally described under the name oleene. Among the various hydrocarbons separated from naphtha by Pelletier and Walter,?? one has been studied with particular attention. This substance called by the discoverers naphthene is very probably the term CI6H,,. Cetylene is the hydrocarbon of the cetyl-alcohol discovered by Dumas and Peligot,f$ in their researches on spermaceti. Cerotylene and melissylene are derived from the interesting wax-alcohols discovered by Mr. Brodie.@ The formulz in the * Phil. Trans. 1825. t J.Pharm. XXIII 454. 2 Chem. SOC. Qu. J. 11 157. § Ann. Ch. Phys. [3] XII 294 11 The same body is formed together with various substances in the decomposition of iodide of amyl by zinc ; for on comparing the composition and properties of the corn- pound lately described by Frankland (Chem. SOC. Qu. J. 111. 30) under the name of valerene there cannot be the slightest doubt that it is nothing but Balard’s amylene. Both substances contain the same amount of carbon and hydrogen and exhibit the Same state of condensation. Their physical properties are absolutely identical ;and if MI:Frankland has observed a boiling-point a few degrees lower than Balard this is perfectly intelligible on the supposition that his substance still contained traces of the more volatile hydride of amyl.Valerene was observed to boil at 350; the boiling- pint of Balard’s amylene is 39O which has lately been verified by Mr. Medlock who has prepared this body on a large scale. 7 Ann. Ch. Phys. [2] LXX 81. +* Ann. Ch. Pharm. XX 50. -fj-Compt. Rend. IX 146. $$ Ann.Ch. Phys.[2] LXII 1. $5 Phi?. Trans. 1849. VOL. III.-XO. x. I CAPTAIN REYNOLDS table are the same as those given by Mr. Brodie although there is still some doubt as to whether they are actually the correct ones ; the doubt arising from the fact of the substances in question being metamorphosed by the action of heat and consequently not admit- ting of density-determinations. The first term missing (the alcohol of which is likewise unknown) in the above series is that which should occupy the place between olefiant gas and butylene.It is this hydrocarbon whose composition must be represented by the formula C6 H, that the succeeding experiments have supplied and to which I propose to give the name of Propylene. This name is like those of the rest of the series derived from the corresponding alcohol in this case still unknown and for which the appellation of Propylic alcohol has been suggested by Dr. Hofmann. PREPARATION OF PROPPLENE. It is well known that the vapour of alcohol is entirely decomposed on passing through a red-hot tube and that the products of decom-position are principally olefiant gas and marsh gas C H and C H, together with several fluid and even solid bodies which have not yet beeii more closely investigated.Amyl-alcohol or fusel-oil under similar treatment might have been expected to yield analogous results in the production of the bodies It was the investigation of this point that gave rise to the dis- covery of the hydrocarbon C H, which is the object of the present communication. The arrangement employed was as follows A long tube of hard German glass was placed in a combustion- furnace one end being connected with a flask containing fusel-oil and the other after passing through a Liebig’s condenser bent so as to dip into a TVoulfe’s bottle partly filled with water which latter was furnished with a flexible tube to convey the evolved gas into a gasorneter. When the tube was red-hot the fusel-oil in the flask was made to boil briskly whicli caused an abundant evolution of gas and a quantity of ON PROPYLENE.liquid collected in the Woulfe’s bottle which appeared to consist of un-decomposed fusel-oil though it is possible further examiuation might show tbat liquid products of decomposition are also present The quantity and quality of the gas evolved were greatly influenced by the temperature of the tube. When the heat was too great little besides ordinary marsh gas was obtained ;on this account an iron tube could not be employed. If on the other hand the tempe- rature was not sufficiently high the greater portion of the fusel-oil passed over undecomposed arid but little gas could be collected. When the operation was properly conducted the resulting gas burnt with a highly luminous flame and when brought into contact with chlorine or bromine gave rise to an abundant formation of oily drops in a manner similar to that of olefiant gas.Some preliminary experiments showed that the gaseous product thus obtained was a mixture of different substances the proportions cof which appeared to vary considerably even in operations which were considered successful ;hence there appeared but little chance %of obtaining satisfactory results from eudioinetrical analysis; I there-fore decided to submit to closer examination the product obtained by the action of bromine upon the crude gas by which alone a consider- able separation was effected. BROMINE-COMPOUND. This compound was formed in the following manner The gas was collected in bottles and bromine added in small portions the bottles being shaken at the same time till the bromine ceased to be deco- iourized.In this manner a quantity of a heavy oily liquid was obtained which was mshcd with water dried over chloride of *calcium and subsequently purified by repeated distillations off quick lime. It is not advisable to prepare this compound by passing the gas directly into bromine as experiment showed that under these circumstances a large quantity of substitution- bodies was formed diminishing considerably the amount of the chief product of the reaction. The limpid oil obtained as above described began to boil at 136O C. the boiling-point rising rapidly to 143O where it re-mained stationary for a considerable time and subsequently rose slowly to 160° when a quantity of a brown liquid remained in the retort which at that temperature began to decompose with evolu- tion of hydrobromic acid; a portion more than three-fourths of the I2 116 CAPTAIN REYNOLDS whole was ultimately separated by rcpeated distillation; its properties are as follow It is a colourless oil of an ethereal odour slightly alliaceous and very similar to that of Dutch liquid.Its boiling-point is 143' (3. It does not solidify at -200 C. Its specific gravity is 1.7. It is decomposed by concentrated sulphuric acid. Combustion with chromate of lead and oxidized copper-turnings gave the following results I. 0.5709 grm. of substance gave 0.3839 , , carbonic acid and 0.1526 , , water.11. 0.4811 , , substance gave 0.3170 , , carbonic acid and 0.1346 , , water. 111. 0.6305 , , substance gave 04095 , , carbonic acid and 0.1729 , , water. The bromine was determined by combustion with lime in the usual manner IV. 0.7934 grm. of substance gave 1.4974 , , bromide of silver. V. 0.5115 , , substance gave 0.9640 , , bromide of silver. Percentage-composition I. 11. 1x1. IV. V. Carbon . 18.33 17.97 17.73 -- CI Hydrogen 2-96 3.10 3.04 Bromine -L -78.58 79.07 The simplest expression to wh,Gh these numbers leal is the for-mula c3 H3 Br as may be seen from the following comparison of the theoretical and experimental values Theory. Mean of -Experimeat, 3 equivs.Carbon . 18-00 18.13 1890 3 , Hydrogen . 3.00 3.02 3.04 1 equiv. Bromine . 78-26 78-85 78.83 99.26 100*00 99-87 ON PROPYLENE. 117 The determination of the density of the vapour however proves that this formula must be doubled if we admit that the elements are condensed in a manner similar to that which obtains in the cor- responding member of the olefiant gas series. Weight of flask with dry air . . 33.2504 grms. Temperature of balance case . . 22.25' (3 Height of barometer . . . 759.4 mm. Temperature at time of sealing . . 198O C Weight of flask with vapour . . 34.0879 grhs. Height of barometer . . . 759.0 'mm. Volume of air remaining in the flask . 4.0 cc. Volume of mercury filling flask .. 204-5 cc. The density of the vapour deduced from the above data is 7-3098 which on comparison with the following theoretical value will sbow that the formula of the compound in question must be c6H6 Br,. 6 equivs. Carbon = 6 vols. = 49920 6 , Hydrogen = 12 vols. = -8316 2 1j Bromine = 4vols. = 22.1776 28.0012 On dividing this total by 4,we have Theory. Experiment. 2'"O'fL = 7.0003 7.3098 4 The excess above the theory is probably due to the partial decom- position of the vapour which caused a small quantity of carbon to be deposited in the flask. If we adopt for the analogous body in the olefiant gas series the term hydrobromate of bromide of acetyl we may call the present compound hydrobromate of bromide of propionyl c6 H Br.H Br. On digesting the oil just described with alcoholic solution of potash very energetic action took place with abundant deposition of bromide of potassium and a liquid distilled over from which on the addition of water a heavy colourless and very mobile fluid separated extremely volatile and of a peculiar odour resembling that of rancid fish. This substance was dried over chloride of calcium and rectified by 118 CAPTAIN REYNOLDS distillation off quick lime. Its boiling-point not being stationary it was treated several times with alcoholic solution of potash which however only appeared to increase the variableness of the tempera- ture of ebullition. The product was therefore separated by fractiozal distillation into portions boiling between 45O and 56O 56O and 60° and 60° and 70°.Analyses of these distillates gave the following results I. 0.6495 grm. of substance boiling from 45O to 56O gave 0.6893 , , carbonic acid and 09348 , , water. 11. 0.4207 , , substance boiling from 56O to 60°gave 0.4516 , , carbonic acid and 0.1580 , , water. 111. 0.4543 ) , substance boiling from 60°to 70°gave 0.5134 , , carbonic acid and 0.1891 ) , water. Percentage-composition I. 11. 111. Carbon . . 29.06 29.26 30.88 Hydrogen . 4.03 417 462 The first of these results will be seen to approximate closely to the formula c H Br as may be seen from the following comparison Theory. Experiment. r-y 6 cquivs. Carbon. . . 36 30.18 29-06 5 , Hydrogen * 5 4-19 4.03 a 1 equiv.Bromine 78.26 65.62 ...-119.26 99.99 As the boiling-point rises the proportion of carbon and hydrogen increases thereby leading to the conclusion that the action of the potash produces in the first instance the body c6 H Br and that afterwards a substance containing more or less oxygen in the place of bromine is formed The formula of this second body may probably be or oxybromide of propionyl which would contain Carbon . . . 42-78 Hydrogen . . 5.94 ON PKOPYLENE. 119 The great loss caused by repeated distillation in the hope of obtaining a constant boiling-point previous to the above hypothesis suggesting itself left me so little substance that I was unable to determine this point more accurately.CHLORINE-COMPOUND. This compound was formed by allowing the crude gas obtained from fusel-oil to meet chlorine in a quilled glass globe when combi- nation took place with evolution of heat; and a heavy oily liquid similar to the bromine-compound collected in the receiver. This liquid was dried over chloride of calcium and distilled repeatedly off quick lime and finally a portion was obtained which boiled at loo0 and 103O. Two chlorine-determinations* gave the following numbers I. 0.4618 grm. of substance gave 1.1694 , , chloride of silver. 11. 0.3659 , , substance gave 0.9256 ,) , Percentage 1. 11. Chlorine . . . . 62.64 62.55 which agrees with the formula c H CI, as may be seen from the following comparison Theory.Mean of -Experiment. 6 equivs. Carbon . . 36.0 31.85 -6 , Hydrogen . 6-0 5-30 -2 , Chlorine 35.5 62.83 62-59 ____I 77.5 99.98 On treating this compound with alcoholic solution of potash 8 decomposition similar to that wliich took place in the case of the bromine-product appeared to result. The perfect analogy in composition and deportment of the com-pounds described with the corresponding terms of the olefiant gas series * The fraction boiling at a constant point was much smaller than in the ease of the bromine-compound a larger quantity of substitution-products being formed. CSPTAIN REYNOLDS ON PROPYLENE. appear to warrant the conclusion that the substance which conibines in the present cases with bromine or chlorine is the hydrocarbon c He In successful operations the proportion of propylene in the gas derived from fusel-oil was about half the original gas.The residue obtained by passing the gas through bromine till the latter ceased to absorb it appeared to consist chiefly of marsh gas; but this point demands a more particular investigation which I intend shortly to make. I also propose to try whether by the use of solvents such as benzol or oil of turpentine it may be practicable to obtain the hydrocarbon C H pure so as to examine it eudiornetrically. On considering the composition of the bodies c6 H Br and c 13 c1 it will be seen that they may be regarded as belonging to the allyl- series; and it may therefore be anticipated that the action upon either of sufphide of potassium and sulphocyanide of potassium will produce respectively oil of garlic and mustard oil sulphide and sulphocyanide of ally1 C H Br -I-K S = C H S + KBr C6 H Br + K C N S = C H C2 N S2 + K Br.I intend to make these reactions the subject of further investiga- tion as well as to complete what is deficient in the experiments already detailed and I hope to have the honour of submitting the results to the Society. I may mention in conclusion that the above inquiry was con- ducted in the Laboratory of the Royal College of Chemistry and I take this opportunity of expressing my thanks to Dr. Hofmann for his kind assistance and advice in the performance of these experiments