High purity 4,4'-Isopropylidine-bis-2,6 dibromophenol and process for the preparation of such high purity 4,4'-Isopropylidine-bis-2,6 dibromophenol

摘要

A high purity 4,4'-isopropylidine-bis-(2,6-dibromophenol) characterised by ionic bromides less than 10 ppm, colour in alkaline solution from 60-100 HU, HPLC purity about 99.9%, APHA of 20% MeOH solution less than 10.0 HU, Fe less than 1.0 ppm, turbidity of 20% MeOH solution less than 5 NTU, pH of 10% slurry 6.0-7.0, size of the crystal particles, 250 to 280 microns with angle of repose lower than 30°. The product is produced by reacting Bisphenol-A with bromine in a "water-immiscible" polar solvent in the presence of hydrogen peroxide, aging the reaction products after the reaction, eliminating the excess bromine by reducing agents, washing the product layer with a combination of anionic surfactant, alkali, reducing agent and demineralised water under controlled pH conditions, partially distilling the organic solvent chilling the medium containing the product, filtering the crude product, boiling the crude product with alkali, reducing agent and demineralised water, filtering the TBBA, washing the product with demineralised water and drying to obtain the final high purity TBBA with high yield.