GB283841A - Improvements in and relating to the manufacture of synthetic rubber - Google Patents

Abstract

283,841. I. G. Farbenindustrie Akt.- Ges. Jan. 15, 1927, [Convention date]. Caoutchouc, synthetic.-Hydrocarbons suitable for the manufacture of synthetic rubber, such as butadiene, isoprene, and dimethylbutadiene, are polymerized by treatment with an alkali metal, such as sodium or potassium, in an atmosphere of hydrogen, nitrogen, or carbon dioxide and in the presence of an organic hydroxy compound or ether; the quantity of organic hydroxy compound employed should not be sufficient to react with all the alkali metal present. It is preferred to use an organic hydroxy compound or ether of high molecular weight, such as starch, cellulose, a cellulose ether, or superficially oxidized rubber. The reaction mixture may include an inorganic hydroxy compound, the presence of which in the mixture may be ensured by using superficially oxidized sodium or by treating the hydrocarbon in a moist state. The reaction mixture mav include also an inert solvent, such as a hydrocarbon, which may be removed from the product to any desired extent. The polymerization may be effected in the cold or at a raised temperature, and the mass may be in motion or at rest. According to the examples, (1) isoprene, glycerine, and sodium wire are agitated together at 60‹ C. in an atmosphere of carbon dioxide until a polymerized product is obtained; (2) dried isoprene is mixed with starch and sodium and the mixture is treated as in example 1; (3) isoprene previously saturated with hydrogen is mixed with ethyl cellulose and superficially oxidized sodium and is polymerized at 40-50‹ C. in an atmosphene of hydrogen; (4) imperfectly dried isoprene containing isoprene alcohol as an impurity is treated with sodium, solid caustic soda, and benzene, and, after the mixture has been saturated with carbon dioxide, is polymerized at 60-70‹ C. in an atmosphere of carbon dioxide.