METHOD OF PROCESSING RETURN PRODUCTS OF BUTYL RUBBER PRODUCTION Russian patent published in 2001 - IPC

FIELD: production of butyl rubber; processing return products of butyl rubber production. SUBSTANCE: proposed method consists in processing return products which include mixture of vapors of isobutylene, isoprene and methyl chloride removed from stage of degassing of butyl rubber dispersion obtained at low-temperature catalytic copolymerization of isobutylene with isoprene in methyl chloride medium which includes compression of vapors, condensation of these vapors and rectification of hydrocarbons at separation of methyl chloride for preparation of solution of catalyst, methyl chloride isobutylene fraction and return isobutylene for polymerized charge; compressed vapors of hydrocarbons are divided into two flows which are first directed for separation of methyl chloride isobutylene fraction containing 1 to 3 mass-% of isobutylene; one flow is directed for rectification in gaseous state; second flow of hydrocarbon vapors is subjected to condensation, after which it is directed for rectification in liquid state and 15 to 25 % of overhead methyl chloride isobutylene fraction are directed for separation of methyl chloride which is fed for preparation of catalyst solution; remaining part of distilled fraction is fed for preparation of polymerized charge; preset content of isobutylene in methyl chloride isobutylene fraction is stabilized through change of takeoff of bottoms liquid and/or change of ratio of gaseous and liquid flows supplied for separation of methyl chloride isobutylene fraction. Gaseous flow of hydrocarbons directed for separation of methyl chloride isobutylene fraction is maintained within 30 to 50% of total mass of hydrocarbons. EFFECT: considerable reduction of content of isobutylene in methyl chloride for catalyst solution; reduced power requirements; enhanced homogeneity of rubber. 2 cl, 1 dwg