METHOD FOR PREPARING ISOPRENE RUBBER Russian patent published in 2005 - IPC

FIELD: chemical technology, rubbers.

SUBSTANCE: invention relates to a method for preparing synthetic rubbers. Method for preparing isoprene rubber involves polymerization of isoprene synthesized by decomposition of 4,4-dimethyl-1,3-dioxane on catalyst working in the cyclic regime contact - regeneration followed by isolation of isoprene from hydrocarbon condensate of contact gas and regeneration of catalyst in the presence of air and steam to form regeneration gases in the medium of isopentane as a hydrocarbon solvent and Ziegler-Nutt's catalyst adding in aromatic solvent. Then polymer solution is treated with stopper agent, washing out from catalyst decomposition products, stabilization of polymer with antioxidant, aqueous degassing rubber and processing hydrocarbon solvent distilled off in degassing, aromatic solvent for catalyst, C₄-hydrocarbons and unpolymerized isoprene - recurrent products - by rectification that involves azeotropic drying and distilling off C₄-hydrocarbons, isolating recurrent isopentane-isoprene fraction and separating remained C₅-hydrocarbons from low-boiling hydrocarbons using heat for supply that is necessary for rectification recurrent products in their processing, hot vapor condensate and steam followed by feeding the isolated isopentane-isoprene fraction for preparing charge for polymerization. Also, method involves azeotropic drying charge, distillation off remained C₅-hydrocarbons and aromatic solvent from low-boiling hydrocarbons and drying rubber. Method involves using regeneration gases in decomposition of 4,4-dimethyl-1,3-dioxane as a heat carrier used for heat supply necessary for rectification in processing recurrent products, for heating circulating vapor condensate to temperature 96-125°C. Then heated vapor condensate is separated for two flow. The first flow in the amount 75-85% of the total flow is fed in rectifying column boilers for azeotropic drying the recurrent solvent and distillation off C₄-hydrocarbons, separation of recurrent isopentane-isoprene fraction from low-boiling hydrocarbons and azeotropic drying the charge. The second flow in the amount 15-25% of the total flow of circulating vapor condensate is mixed with steam up to temperature 140-150°C and fed in rectifying column boilers for distilling off remained C₅-hydrocarbons and aromatic solvent from low-boiling hydrocarbons. Invention provides reducing specific consumptions of raw and energy resources. Method can be used for preparing rubbers used

in manufacturing tires and rubber-technical articles and can be applied in petroleum chemistry industry also.

EFFECT: improved method for rubber preparing.

1 dwg, 3 ex