March, 1910.] 



195 



GUMS, RESINS, SAPS AND EXUDATIONS, 



RUBBER AND ITS SUBSTITUTES. 



(From the Chemist and Druggist, Vol. 



(LXXVI , No. 1562, January 1, 1910.) 



The circular which was issued recently 

 by the Synthetic Rubber Co., announc- 

 ing the proposed voluntary winding- 

 up, on the grounds that further ex- 

 penditure was not justified, has given 

 great satisfaction to dealers and brokers 

 in rubber, although it may be said that 

 in Mincing Lane the synthetic bogey 

 never caused much apprehension, even 

 though Professor Dunstan, at the British 

 Association meeting in 1906, confidently- 

 predicted the synthetic production of 

 rubber before the Association met again 

 at York. At present there is still no 

 likelihood of the prophecy coming true, 

 but the commercial production is by no 

 means an impossibility. It is interest- 

 ing from this point of view to give a 

 re'sume' of the many attempts, especi- 

 ally during the last decade, to make 

 artificial rubber or prepare satisfactory 

 substitutes for it. The only known 

 actual synthesis of caoutchouc is 

 that accomplished by Bouchardet and 

 Tilden by polymerising isoprene (CH) : 

 (CH2). (CH 2 ) : (CH), which is itself one of 

 the distillation-products of caoutchouc. 

 Wallach and Tilden (1892) also showed 

 that isoprene obtained from turpentine 

 behaves similarly to that obtained in 

 the destructive distilation of rubber. 

 Kondakow. in 1902, prepared a substance 

 closely resembling caoutchouc, by the 

 action of light for a year on di-iso- 

 propenyl or methyl isoprene. A British 

 patent granted in 1907 proposes to con- 

 vert acetylene and ethylene into di- 

 vinyl under the influence of a dull red 

 heat, which latter product yields metyl 

 di-vinyl or isoprene on treatment with 

 methyl chloride. The isoprene is then 

 to be condensed to rubber. Other pro- 

 cesses have been patented on the assump- 

 tion that coal tar contains polymers of 

 isoprene or compounds convertible into 

 such substances. Thus SeguinandBoussy 

 de Sales patented in Prance during 1903 

 a process according to which tar (con- 

 taining isomers of caoutchouc) is seeded 

 with caoutchouc particles or treated 

 with other appropriate ferment at 00° C. 

 in an atmosphere of nitrogen, Later 

 a method was patented of preparing the 

 "ferment." To obtain this the "thick 

 deposit" from a caoutchouc solution in 

 benzine, kept at a temperature of 50° C. 

 and exposed to daylight in a closed 

 bottle, is re-dissolved and then precipi- 

 tated again by alcohol. The precipitate 



is scattered over the surface of a mixture 

 of coal tar and boric acid which is 

 maintained at 50° C. in an atmosphere 

 of oxygen. A brownish-grey powder is 

 stated to be formed on the walls, and 

 this is the "ferment" in an active 

 form. Prior to the last process, Jasset 

 (1902) stated in his specification that 

 coal tar (4 parts) and boric acid (1 part), 

 heated until the burning vapours were 

 coloured green and then kept at 60° C. 

 in a current of oxygen, yielded a brown 

 highly elastic body to suitable solvents 

 after "drying on a water-bath. Phos- • 

 phoric or iodic acid may replace boric 

 acid. An American patent, byDupont 

 and Franklin (1903), gives a variation 

 of the above, since the tar and boric 

 acid are dissolved in alcohol, heated until 

 vapours burning with green flame are 

 evolved, then oxygen is passed through 

 the mixture, Blum and Carpenter 

 (French patent, 1909) propose to obtain 

 a glutinous mass consisting of a hydro- 

 carbon of the formula (CsHs^ by sub- 

 jecting vegetable substances, such as 

 peat, to fermentation at about 60° C, 

 and simultaneously or subsequently to 

 a reducing process. The enzyme is 

 stated to be present in imperfectly 

 formed caoutchouc, or an " enzyme 

 which will produce alcohols of a series 

 higher than the oJefine series " may be 

 used. The reducing agent is a nitro- 

 genous compound, preferably the red 

 substance resembling seed in red Upper 

 Congo rubber, with the addition of 

 mineral salts. In 1908 the same two 

 patentees specified a process to produce 

 "synthetic Para rubber" by treating 

 with a nitrogenous derivative of irone, 

 the mucilaginous mass containing a 

 large percentage cf isoprene " pro- 

 duced from fermented peat, etc. The 

 irone was stated in a subsequent patent 

 to be obtained from roots of species of 

 Iris. The irone is converted by chlorine 

 into a hydrochloride, then by addition 

 of a suitable substance, -preferably an 

 amide, into a nitrogenous compound. 

 Protein-coagulating enzymes are known 

 to occur in the latex of rubber-producing 

 plants, but exactly in what form 

 caoutchouc pre-exists is not known ; but 

 to produce artificial rubber from tar by 

 a vclatile enzyme capable of growth 

 does not accord with known facts. 



Rubber substitutes have met with 

 greater success since at present consider- 

 able difficulty is experienced in obtain- 

 ing rubber goods f rea from substitutes. 

 Their use as a cheapener is responsible 

 tor many of the defects to which rubber- 



