Knowledge. 



With which is incorporated Hardwicke's Science Gossip, and the Illustrated Scientific News. 



A Monthly Record of Science. 



Conducted by Wilfred Mark Webb, F.L.S., and E. S. Grew, M.A. 



FEBRUARY, 1913. 



SYNTHETIC RUBBER. 



By GEOFFREY MARTIN, Ph.D., M.Sc, B.Sc. 



Author of 



Lecturer on Chemistry at Birkbeck College, London. 



Practical Chemistry," " Triumphs and Wonders of Modern Chemistry," "Industrial and Manufacturing 

 Chemistry," "Researches on the Affinities of the Elements." 



(Continued from page 40.) 



We now come to discuss methods for obtaining 

 butadiene and isoprene from starch, which, next to 

 cellulose or wood, is the most abundant of all 

 vegetable material, occurring in cereal grains and 

 potatoes. 



There are several 

 methods of trans- 

 forming starch into 

 isoprene. One of 

 the processes now 

 actually being 

 worked is known 

 as the " fusel oil " 

 route, and was first 

 suggested by Dr. 

 F. E. Matthews, of 

 the Synthetic Pro- 

 ducts Company. 



Maize or potatoes 

 are made into a 

 mash with water, 

 which is then inoc- 

 ulated with new 

 varieties of bacteria 

 discovered by Pro- 

 fessor A. Fernbach, 

 of the Pasteur In- 

 stitute of Paris, 

 and the whole is 



allowed to ferment for about a week in a special vat 

 (see Figure 31), when about forty-two per cent, of the 

 starch contents were found by Dr. Otto Hehner, the 

 well-known analyst, to have been converted into fusel 



Figure 42. 



Messrs. Strange & Graham's Apparatus for the production of butadiene 

 from butylene dichloride. 



oils, the main constituent being butyl alcohol. 

 Figure 45 shows the vats now being erected by the 

 Synthetic Products Co., for the manufacture of fusel 

 oil on a commercial scale. By varying the condi- 

 tions of fermenta- 

 tion acetone can be 

 obtained at the 

 same time in large 

 quantities. 



Next, the fluid is 

 removed from the 

 vat and is distilled, 

 whereby the fusel 

 oils and acetone 

 are separated from 

 the watery residues. 

 Next, into the 

 heated fusel oil a 

 stream of dry 

 hydrochloric acid 

 gas is passed 

 (which, as every 

 schoolboy knows, 

 is made by the 

 action of sulphuric 

 acid on common 

 salt), when mono- 

 chlorides are 

 formed thus : — 

 CH„CH 2 CH.2CH.,C1 + H 2 



Rutyl Chloride. Water. 



CH:,CH 2 CH,CH,OH + HC1 = 



Butyl Alcohol. Hydrochloric 



Acid Gas. 



The butyl chloride thus obtained is then treated 



41 



