ENVIRONMENTALLY SAFE METHOD FOR PRODUCTION OF HIGH- PURITY TETRABROMOBISPHENOL A Russian patent published in 2005 - IPC

FIELD: industrial organic synthesis.

SUBSTANCE: in production of high-purity tetrabromobisphenol A serving as intermediate of polymers employed for electronic equipment and other applications. When producing tetrabromobisphenol A, corrosive liquid bromine serving as bromination agent is replaced by sodium bromide/hydrobromic acid system. Moreover, sodium bromate is used as oxidant but also as bromination agent in order to utilize hydrobromic acid produced in bromination process. Reaction is carried out at 10-15°C in methylene chloride/water or carbon tetrachloride/water mixture in presence of hydrobromic acid and sodium lauryl sulfate. Crystalline product precipitated on the bottom of reaction vessel is filtered, washed, and weighed. Exhausted organic layer is recycled into subsequent batches to maximally increase total output of product recovered directly in the form of solid. Yield of desired product in the first batch is 50-70% and 90-100% after recycling of exhausted organic layer. Pure and colorless tetrabromobisphenol A has melting point 178-182°C.

EFFECT: omitted use of corrosive liquid bromine without loss in quality.

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