Patent ID: 6245951
Filing Date: 2001-06-12
Classification: C07C

Abstract:
A semicontinuous method for production of bisphenols by condensation of a dihydric phenol and a ketone or aldehyde comprising the steps of:(a) continuously condensing the dihydric phenol and the ketone or aldehyde in a first pre-reactor to produce a partial reaction product in which the reaction of the dihydric phenol and the ketone or aldehyde is 10 to 70% complete;(b) continuously condensing the dihydric phenol and the ketone or aldehyde in a second pre-reactor to produce a partial reaction product in which the reaction of the dihydric phenol and the ketone or aldehyde is 10 to 70% complete; and(c) continuously removing partial reaction product from the first and second pre-reactors and introducing the removed partial reaction product to a batchwise completion reactor, wherein a stream of water or aqueous hydrochloric acid is added in alternating intervals to the first and second pre-reactors.