A DEPHENOLIZATION PROCESS FOR OBTAINING ULTRAPURE POLYCARBONATE GRADE BISPHENOL A

摘要

There is provided a process for directly obtaining high purity or ultrapure and polycarbonate grade bisphenol A by applying gas-solid dephenolization at low temperature to remove phenol from an adduct of bisphenol A with phenol comprising introducing the adduct into a vacuum or inert gaseous flow dephenolizer, bringing the adduct to a temperature below the melting point thereof in vacuum or in the presence of an inert gaseous stream to decompose the adduct crystals into a gas phase and a solid phase, removing the phenol with the inert gaseous stream, and recovering the phenol after condensing thereof, the remainders in the vacuum or gaseous flow dephenolizer are the expected bisphenol A. The process of the process lasts a much shorter period of time, and the energy costs are substantially decreased. This bisphenol A produced by the process has desirable colour and high purity, and can be used as raw materials for production of polycarbonate for optical use.