io SCIENCE PROGRESS 



3-diene. Many methods for the preparation of these bodies have 

 been suggested . Turpentine was originally proposed as the raw 

 material, but, owing to its limited supply and frequent fluctua- 

 tions in price, attention was directed to other substances, such 

 as wood, starch, sugar, acetylene, coal-tar and petroleum. In 

 1910 the Synthetic Products Company patented a method of pre- 

 paring isoprene from fusel oil. The fraction distilling at 128 - 

 131 ° consists of iso-amyl alcohol, (CH 3 ) 2 : CH . CH 2 . CH 2 OH, 

 and active amyl alcohol, CH 3 .CH 2 .CH(CH 3 ) . CH 2 OH, which are 

 converted into their monochloridcs with hydrochloric acid, and 

 then chlorinated in such a way that only dichlorides result, 

 such as (CH 3 ) 2 CH.CHC1.CH 2 C1, (CH 3 ) 2 CC1 .CH 2 .CH 2 C1 and 



^tt* yCH . CH 2 . CHoCl. These are passed over soda-lime at 



470 , giving a 40 per cent, yield of isoprene. As the amount 

 of fusel oil available is small, Fernbach and Stange endeavoured 

 to devise a moans for its production in Larger quantities. And 

 in 191 1 they patented a method involving the cheap production 

 of butyl alcohol and acetone by the fermentation of starch 

 with the aid of the butylic bacillus. Butyl chloride obtained 

 from the alcohol is then carefully chlorinated with the production 

 of the dichlorides CH 3 .CH 2 . CHC1 .CH 2 C1, CH 3 .CHC1 . CH 2 . 

 CH 2 C1 and CH 2 C1 .CH 2 .CH, .CILC1 which yield butadiene on 

 passing over heated soda-lime. 



Various means have been proposed for the polymerisation 

 of the hydrocarbons obtained. In 1909 the Bayer Company 

 employed the application of heat to the substance contained in 

 sealed tubes . The following year Harries found that the presence 

 of acetic acid accelerated the change. The Bayer Company 

 showed that the acetic acid probably acted as a diluent. And 

 the use of other agents such as alkalies, alkaline earths, urea, 

 blood, etc., with or without preliminary heating, have been 

 suggested. 



The most dramatic incident in the race between the 

 English and German firms was the almost simultaneous dis- 

 covery of the value of sodium as a polymerising agent. Harries 

 found, at the end of 19 10, that sodium causes the change to 

 take place quickly, and practically quantitatively, at a low 

 temperature. The method was patented by the Bayer Company 

 early in 191 1. Dr. Matthews had, however, been investigating 

 the action of sodium on dimethyl-allene, and in July 19 10 it 



