BROMBUTYL RUBBER PRODUCTION PROCESS Russian patent published in 2002 - IPC

FIELD: rubber industry. SUBSTANCE: brombutyl rubber is prepared by treating 10-25% solution of butyl rubber in inert hydrocarbon solvent with brominating agent (bromine and/or bromine-containing hydrocarbon solvent), neutralizing brominated butyl rubber solution with alkali solution, wet degassing, and drying of product. Process is distinguished by that after washing with water and neutralization with aqueous alkali solution of brominated butyl rubber solution separated from wash water, the latter is combined with depleted alkali solution to give water stream containing bromine compounds, which is acidified to pH 1.5-2.0, oxidized by oxidant, and released free bromine is extracted with hydrocarbon solvent. Extract solution is settled to remove water and reused to brominate butyl rubber. As above-mentioned oxidant, gaseous chlorine, chlorine-containing agent, potassium and ammonium persulfates can be used and oxidation of bromine compounds is carried out until redox potential 960-980 mV is achieved. EFFECT: enhanced process efficiency. 6 cl, 1 dwg