Catalysifi or the Speedmg-up of Chemical Reactions 45 



study of isoprene and established its structure. In the course of 

 a paper read at Birmingham in 1893 he said : "I was surprised a 

 few weeks ago at finding the contents of the bottles containing 

 isoprene from turpentine entirely changed in appearance. In 

 place of a limpid, colourless liquid, the bottles contained a dense 

 syrup in which were floating several large masses of solid of a 

 yellowish colour. Upon examination this turned out to be india- 

 rubber " 



This then represents the tirst artificial production of rubber* 

 Efforts were made to accelerate the polymerisation of isoprene to 

 rubber and many agents weie found to promote the change. In 

 1910 Matthews discovered that sodium had a very pronounced 

 catalytic effect and by varying the conditions the change could be 

 completed in a few hours or a few days. The condensation of 

 isoprene to form rubber can therefore be accomplished and the 

 next step in the process to make it a commercial proposition is to 

 ensure large supplies of isoprene at a low cost. Turpentine is 

 out of the question, not only on account of its price, but also 

 because only very limited amounts of it are available. A 

 fermentation process was devised whereby starch, obtained from 

 potatoes or grain, could be converted into fusel oil, consisting 

 largely of butyl alcohol. This, by the action of hydrochloric acid 

 and the subsequent action of chlorine, is converted into a 

 dichloro-derivative, and M^hen the latter is passed over heated 

 lime it is broken down into butadiene — ^a substance which 

 resembles isoprene in its main chemical properties. By the 

 agency of sodium the butadiene is polymerised to form an artificial 

 rubber. It was claimed that rubber could be produced by this 

 method at a cost (pre-war) of about sixpence a pound. It is too 

 early yet to give a pronounced opinion about the process, but it 

 seems to have great possibilities. The scarcity of rubber in Gler- 

 many during the war might perhaps be taken as an adverse 

 criticism of the manufacture of artificial rubber, or of the value 

 of the rubber so produced. 



