METHOD OF PREPARING BUTYL RUBBER Russian patent published in 2001 - IPC

FIELD: preparation of butyl rubber in petrochemical industry. SUBSTANCE: method of preparing butyl rubber by copolymerization of isobutylene with diene hydrocarbon carried out in two or more reactors operating in parallel in methyl chloride diluent in the presence of catalyst comprises deactivation of catalyst, distillation of methyl chloride and unpolymerized monomers by aqueous degassing at excessive pressure in first step degassing dearators and at residual pressure 0.02-0.04 MPa in subsequent steps of degassing created by vacuum device with vapor-gas mixture withdrawn into first step degassing dearators also condensation of degassing vapors and recycling of aqueous condensate into first step degassing dearators, compression, drying and rectification of hydrocarbons and recycling thereof to prepare blend and catalyst solution, stabilization of polymer with antioxidant, averaging of rubber crumb and drying thereof, reducing back pressure by vacuum device by withdrawing degassing vapors out of common header installed near first step dearators, with one or two streams directed into second common header in front of capacitors, and withdrawn through contact out of first step degassing dearators together with aqueous condensate taken off after each stage of condensation of steam vapors present in degassing vapors cooled in two stages at temperature of 5-10 C in second stage, uncondensed moistened hydrocarbon vapors are then combined in third common header and compressed, and stage of degassing of rubber is carried out in two or more degassing steps and rubber dispersion is simultaneously concentrated in water as degassing process proceeds till rubber content of 7-12 wt % is attained by withdrawing some water from corresponding steps into first step degassing dearators and adjusting rubber dispersion temperature at 45-60 C in last degassing step, some water from rubber dispersion is withdrawn into first step degassing dearators preferably from second and fourth degassing steps. EFFECT: intensified process, lower specific energy consumption and improved ecology. 2 cl, 1 dwg _