and Magazine of the Ceylon Agtcultt&ral Society.— July, 1912. 93 



tone, by the fermentation of starch, by means 

 of certain bacteria ; and the isoprene without 

 which "synthetic" is impossible, hitherto ob- 

 tained by condensing turpentine, is now ob- 

 tained from iso-amylatropol, a constituent of 

 fusel oil. 



It may be found that Professor Perkin is rely- 

 ing too much for cheapness of production on 

 the possible sale of by-products, the market for 

 which is not always easy to find, and still more 

 easily dislocated when these begin to be turned 

 out in unwonted quantity. 



PROFESSOR PERKIN'S PAPER. 



A meeting of the London Section of the Society 

 of Chemical Industry was held at Burlington 

 House on June 17. Mr E Grant Hooper presided 

 over a crowded meeting. The first paper, by 

 Professor W H Perkin, JB'.R.S., was entitled 

 "The Production and Polymerisation of Iso- 

 prene and its Uomoiogues," and turned out to 

 be an extremely interesting account of the work 

 of an English committee of chemists and bac- 

 teriologists undertaken with a view to the 



PRODUCTION OF SYNTHETIC RUBBER ON A 

 COMMERCIAL BASIS. 



As the story was unfolded in dramatic se- 

 quence it proved that our chemists are as virile 

 as ever, and it completely vindicated the early 

 work of English chemists upon the authenticity 

 of which some doubt has been expressed in Ger- 

 many. Professor Perkin began by explaining 

 that at the end of 1909 a group of chemists and 

 bacteriologists was formed by Mr E Halford 

 Strange to study the production of synthetic 

 rubber. At the head of the group was Dr. F E 

 Matthews, who suggested a method of prepar- 

 ing isoprene in which acetone and later fusel 

 oil were employed as the raw material. The lec- 

 turer had at the same time devised a process 

 starting from glycerin, and this led to an alli- 

 ance. A committee of fifteen chemists was ulti- 

 mately formed, with Sir William Ramsay as 

 consultant, and Professor Fernbach, of the 

 Pasteur Institute, Paris, as bacteriologist. Pro- 

 fessor Perkin reviewed the work of the earlier 

 investigators to prove, in view of statements 

 made by the Bayer Co., that much pioneer work 

 in this field belongs to this country and France, 

 A careful search has been made of the litera- 

 ture of the subject, the chief events being : — 

 1860. Greville Williams isolated isoprene and 

 observed its transformation into a rubber-like 

 body. 



1875. Bouchardet proved that rubber is a 

 polymer of isoprene, and in 



1879 propared isoprene from turpentine. 



1882. Tilden first polymerised isoprene into 

 rubber by the action of hydrochloric acid and 

 nitrosyl chloride. He also suggested the cor- 

 rect formula for isoprene. In 



1884 he further investigated the production of 

 isoprene by the pyrogenic decomposition of tur- 

 pentine, and in 



1892, in a paper before the Birmingham Philo- 

 sophical Society, showed that synthetic rubber 

 is capable of being vulcanised, 



Professor Perkin then drew attention to the 



HISTORIC SPECIMENS CF ISOPPT5NE PREPARED 

 BY SIR WILLIAM TILDEN, 



which were on the lecture- table. One spec- 

 imen in a bottle hermetically sealed had 

 become syrupy, and another to which air had 

 had access was dark-coloured and had become 

 converted into rubber. This was proved by 

 sticking into it a glass rod, to which it adhered 

 and showed its elasticity. Continuing, the lec- 

 turer recounted that in 1907 and onwards the 

 high price of rubber stimulated research with 

 the object of preparing rubber synthetically. 

 The Bayer Co. in 1908 obtained a patent for a 

 method of polymerising isoprene by means of 

 heat, but the patents up to this time did not 

 contain much that was not known before. Experi- 

 mental work of Kondakow, Motiewsky, Thiele, 

 Harries, and Klages was referred to, these che- 

 mists employing compounds containing the con- 

 jugated double linking — C = C — C = C — which 

 is usually connected with a tendency to polyme- 

 rise. Then followed a dramatic episode in the 

 almost simultaneous discovery of the scientific 

 fact that isoprene can be readily polymerised 

 by means of sodium. In September 1910 Dr. F. 

 E. Matthews observed that isoprene which had 

 been left in contact with metallic sodium since 

 July had turned into a solid mass of rubber. 

 Professor C. Weizmann had also suggested that 

 dimethylallene could be converted into rubber by 

 means of sodium. Further investigation proved 

 that sodium is a general polymerising agent of 

 first-rate importance. The first announcement 

 of this discovery was made by Dr. Carl Harries, 

 of the Bayer Co., but when Dr. Harries applied 

 for an English patent he found that he had been 



COMPLETELY ANTICIPATED BY DR. MATTHEWS S 

 APPLICATION 



three months before. The polymerising action 

 of sodium is practically quantitative, and is not 

 seriously affected by impurities. It will take 

 place in the cold or in moderate heat, which is 

 an advantage. The lecturer than called at- 

 tention to some tubes of isoprena in which had 

 been immersed for varying timo a spiral of 

 sodium wire, Selecting one which had been in 

 contact for five days, he pointed out that tho 

 sodium had been broken down to a powder, and 

 a viscous mass had termed at the bottom. 

 The lecturer's assistant then precipitated the 

 rubber by means of acetone and exhibited a 

 mass of rubber to the audience. The rubber 

 was snowy white, but, it was explained, be- 

 comes transparent after standing for some 

 time. This discovery renders the production 

 of rubber possible if di-vinyl or erythrene 

 isoprene, di-iso-propenyl, butadiene, lor other 

 similar compounds containing conjugated double 

 linkings can be prepared cheaply. Various raw 

 materials were suggested. It was thought that 

 the " cracking " of petroleum spirit was a pro- 

 mising source of the hydrocarbons, but the yield 

 was less than from turpentine, and there were 

 present many other bodies which made the puri- 

 fication a costly matter. The supply of tur- 

 pentine is limited, and, therefore, subjected to 

 great fluctuations of price. In surveying the 

 various organic substances which could be em- 

 ployed the fact was kept in mind that rubber may 



