February, 1913. 



KNOWLEDGE. 



43 



be produced at thirty pounds a ton, by Fernbach's 

 new process. 



It should also be noted that isoprene may be 

 obtained from acetone in several ways. For example, 

 Fr. Bayer & Co., of Elberfeld, propose to manufacture 

 isoprene by condensing formaldehyde with acetone 

 in the presence of weak alkali, to form 2-ketobutanol 

 and other products :— CH 3 COCH.,+ CH 2 = CH 3 

 COCH 2 CH 2 CH 2 OH. From this water is split off 

 and methylene acetone is produced : — CH 3 COCH 

 = CW. Z , and from this 

 isoprene is produced. Dr. 

 F. E. Matthews has also 

 worked out methods for 

 changing acetone into 

 isoprene. However, these 

 methods do not appear to 

 be commercially remunera- 

 tive. 



To sum up, then, three 

 practical methods have 

 been devised for obtaining 

 rubber from starch : — 



(1) From Fernbach's 

 fusel oil — consisting princi- 

 pally of butyl alcohol and 

 costing about thirty pounds 

 to forty pounds per ton ; 

 (2) from industrial alcohol 

 through aldehyde, alcohol 

 costing threepence per 

 pound ; (3) from fusel oils 

 obtained from spirits — 

 which at present cost about 

 one hundred and forty- 

 pounds per ton. 



The raw material is in 

 every case obtained by 

 agricultural processes. 

 Table 10 represents the 

 new industries and their 

 relation to the old. (See 

 page 44.) 



Since the whole chain 

 of industries mentioned in 

 this Table ultimately rests 



rubber starts from raw petroleum. From petroleum 

 both butadiene and isoprene have been obtained by 

 special " cracking " processes — for example, passing 

 it over red hot surfaces impregnated with special 

 "contact" substances, and, indeed, at the present 

 time the writer is aware of a vast amount of secret 

 research going on with this object in view. 



Somewhat more promising are chemical processes ; 

 to give an example, according to one suggested 

 process the petroleum is fractionated, and a product 



containing isopentane, 

 (CH 3 ) 2 CH.CH 2 CH 3 , is 

 isolated. This is then 

 treated with chlorine and 

 a mixture of dichlorides, 

 C 5 H 10 C1 2 , are obtained. 

 These are then sent over 

 hot soda lime, when iso- 

 prene is produced thus : — 

 CH 3 . 



NcCLCHgCHgCl. 

 CH/ 



A dichloride from isopenlane. 



Mr. 



Figure 43. 

 Pirn's Apparatus for 



upon agriculture as a 



basis, it would seem that a good time is coming for 



farmers. 



So far we have discussed the methods of producing 

 rubber from starch, in the form of cereals or potatoes. 

 It must not be forgotten, however, that wood could 

 be used as a starting point for producing mashes 

 capable of fermentation. For example, several 

 processes are known, and are even worked on a 

 limited scale, of converting wood into sugars, which 

 can then be fermented much in the same way as 

 the starch mashes referred to above. Although 

 possible, however, it is improbable for many reasons 

 that such processes will be able to compete with 

 those which use starch as their starting point. 



The next promising method for producing synthetic 



CH 8 



I 

 CH.. = C-CH = CH, 



Isoprene. 



By treating other frac- 

 tions of petroleum in a 

 similar manner not only 

 isoprene but also butadiene 

 and dipropylene can be 

 obtained and converted in- 

 to rubbers in the usual way 

 by treating with sodium. 



There still remains to be 

 considered the production 

 of rubber from turpentine 

 oils. When these are 

 passed under certain con- 

 ditions over hot contact 

 surfaces isoprene may be 

 produced in quite considerable quantities, and a 

 great many patents have been taken out for im- 

 proving the yield. 



The general consensus of opinion among technical 

 chemists, however, is that the raw materials are too 

 expensive to allow a commercially remunerative 

 synthetic rubber to be produced from turpentine oil. 



Before leaving the subject of synthetic rubber 

 manufacture, however, I must say a few words about 

 rubber obtained from still higher homologues of 

 butadiene than isoprene. 



First of all there is the hydrocarbon fl-y -dimethyl- 

 butadiene also known as dipropylene and isopropy- 

 lene. This substance is simply butadiene in which 



C. A. Pirn's Apparatus for the fractional 

 distillation of butylene dichloride. 



