Making high-purity Bisphenol A from phenol and acetone, e.g. for polycarbonate production, involves separating the Bisphenol A-phenol adduct by continuous suspension crystallisation

摘要

A method for making Bisphenol A (BPA) with a purity of more than 99.7% by (a) reacting phenol and acetone using an acid catalyst, (b) separating a BPA-phenol adduct by crystallisation and (c) removing phenol from the adduct, in which (b) involves continuous suspension crystallisation with a total dwell time of more than 4 hours in at least 3 crystallisers, by cooling first to 50-70[deg] C in two parallel crystallisers and then to 40-50[deg] C in a third crystalliser connected in series with the first two. A method for the production of Bisphenol A (BPA) with a purity of more than 99.7%, by (a) reacting phenol with acetone in presence of an acid catalyst, (b) separating a BPA-phenol adduct from the product mixture by crystallisation, filtration and washing, and (c) removing the phenol from the adduct, in which stage (b) involves continuous suspension crystallisation in at least three crystallisers connected in such a way that the mixture is first cooled to 50-70[deg] C in two crystallisers in parallel and then cooled to 40-50[deg] C in a third crystalliser in series with the first two, the total residence time of the mixture over all crystallisers being more than 4 hours.