| abstract |
The subject of the present invention is a process to manufacture high-purity bisphenol A to be used as feedstock for producing epoxy and polycarbonate resins. The method of the invention consists of reacting simultaneously phenol with acetone in the presence of a strong-acid cation-exchanger catalyst, phenol with p-isopropenylphenol resulting from thermal catalytic decomposition of process by-products and recycled to the reaction system, and an isomerizational rearrangement of process by-products to obtain bisphenol A in the presence of a micro- and macroporous cation-exchanger catalyst mixture in the synthesis unit (1). The post-reaction mixture is sent to the bisphenol A and phenol crystallization unit (3), treated to separate phenolic liquor (I), washed with phenolic water, heated to obtain a solution and recrystallized in the recrystallization unit (5) to separate phenol liquor (II). The high-purity bisphenol A is obtained in unit (6) from the adduct using a vacuum distillation process. The separated post-crystallization liquor is treated for use as a washing liquid in the crystallization unit (3) and the recrystallization unit (5) and, after being dried in the dewatering unit (7) and/or treated in the catalytic decomposition unit (8) and by-products' rearrangement unit (9) to obtain bisphenol A, the mixture is recycled to the synthesis unit (1). |