Abstract: An ion exchange resin catalyst containing sulfonated styrene-divinylbenzene copolymer, a porous structure with micropore area and transfer pass networks, the transfer pass network is composed of main pass networks and branch pass networks, in non-swollen state, the pore size of the main pass network is 9.times.10.sup.3 -38.times.10.sup.3 nanometer and the pore size of the branch pass network is 20-150 manometer, the pore size of the micropore area pass is 5-20 nanometer, wherein the pore capacity of the micropore pass with the pore size of 5-10.4 nm is more than 50% of the total pore capacity of the micropore area, and the ratio of the pore capacity of the micropore area to that of the transfer network area is 0.25-1.1. The catalyst is useful to condense phenols with ketones.

Abstract: The present invention provides a method, which can be operated continuously and has a wide scope of application, for destructing part of fines in slurry in a crystallizer to obtain large crystals having high purity and large crystal size, characterized in that first and second filters are installed in the crystallizer, a part of slurry containing only fines of size smaller than the fines cut size is drawn from the crystallizer, through the first filter in the crystallizer to a fines destruction loop for destructing the fines and then to the crystallizer through the second filter in the crystallizer by using a circulating pump. The two filters are switched over at regular interval and washed with each other's effluent to ensure the cintinuous operation of the above process.The present invention also provides a method for preparing crystalline bisphenol A/phenol adduct and bisphenol A with high purity and large crystal size.

Abstract: High purity and ultrapure bisphenol A is prepared in a novel process.

Abstract: A process for producing high-quality polycarbonate grade bisphenol A directly by removing phenol from the adduct crystal of bisphenol A with phenol via a gas-solid reaction at low temperature comprises directly feeding the adduct crystal into a vacuum or pneumatic dephenolizing device under vacuum a inert gas stream, controlling the temperature of the adduct crystal below its melting point, decomposing the adduct crystal into gas phase and solid phase, removing the gas phase phenol and condensing phenol for recovery, well leaving the rest being the desirable bisphenol A. The process possesses easy operation, short procedure, low energy consumption, and high purity and good color of bisphenol A obtained. Bisphenol A produced according to the process of the invention may be used as the raw material for producing polycarbonates for optical use.