IMPROVED METHOD FOR REMOVING CONTAMINATION OF CRYSTALLIZING COOLER CONTAMINATED WITH BISPHENOL-PHENOL ADDUCT

摘要

PROBLEM TO BE SOLVED: To improve the recovery of bisphenol A in the production of dihydric phenols by dissolving contaminated cooling and crystallization surface with phenol containing a specific amount of water in the crystallization of phenol- bisphenol A adduct on the upper part of a crystallizer. ;SOLUTION: An excess mol of phenol is charged together with a ketone compound to a reaction zone 12 and subjected to continuous condensation reaction in the zone at 40-95°C to precipitate a reaction product containing 1:1 adduct of bisphenol compound and phenol compound and the solid adduct is separated by a crystallizer 14. In the above process, the adduct deposited on the cooling surface in the crystallizer 14 is dissolved with a phenol solution containing 5-40 V/V% of water at about 40-90°C and the delta T of the cooling surface of the crystallizer is maintained to about 4°C to achieve the removal of the contamination on the surface of the crystallizer.;COPYRIGHT: (C)1999,JPO