METHOD FOR PRODUCTION OF CHLORINATED DIENE COPOLYMERS Russian patent published in 1999 - IPC

FIELD: polymer production. SUBSTANCE: method including chlorination of butadiene and water-alkali catalytic dehydrochlorination of resulting C₄-chlorohydrocarbons followed by polymerization of chlorinated dienes in presence of polymerization regulators is distinguished by that liquid-phase chlorination of butadiene is carried out in boiling ethyl chloride at butadiene-to-chlorine molar ratio (1.2-3):1 accompanied by recycling of ethyl chloride, resulting mixture of 3,4-dichloro-1-butene, 1,4-dichloro-2-butene, trichlorobutene, and tetrachlorobutene is dehydrochlorinated in boiling ethyl chloride at weight ratio of ethyl chloride to chlorohydrocarbons (1-3):1 by the use of 42-45% aqueous sodium hydroxide in presence of 0.3-0.8% (based on the weight of chlorohydrocarbons) of triethyl- and tributyl-1-chlorobuten-2- ylammonium chloride obtained directly in chlorohydrocarbon mixture by adding trialkylamines to alcohol (1,4-butenediol, C₁-C₄-alkanol, or benzyl alcohol) at trialkylamines-to-alcohol molar ratio 1:(1-5), after which organic phase containing at least ethyl chloride, β-chloroprene, 2,3- dichlorobutadiene, and 1,4-dichloro-2-butene is separated. The contents of organic phase are then subjected to polymerization in ethyl chloride at 40-80 C in presence of radical initiators and polymerization regulators for 20 to 40 hr followed by distillation of ethyl chloride with unreacted chlorodienes and precipitation of polymer with methanol. 1,4-Dichloro-2- butene is finally isolated from methanol. EFFECT: reduced losses of reactants. 3 cl, 3 ex