Industrial Innovations

THPE is used as a branching agent in the synthesis of polycarbonates, a high performance engineering polymer. (a) The development consists of an improved process comprising. 1. Higher conversion efficiency of 96% with selectivity of 86% for THPE; 2. Azeotropic removal of water of reaction to drive condensation for higher conversion; and 3. Simple and cost effective isolation of THAPE by precipitation with an anti solvent. (b) The only known manufacturer of THPE is M/s Salisbury Chemicals in US, who produce it under license from Hoechst Celanese (PhOH). In the existing process the condensation of 4-hydroxyacetophenone with phenol is accomplished using mineral acids as catalysts. These processes however require extended reaction times and lead to substantial amounts of various side products and low yields of THPE. In the process developed the reaction is carried out in the presence of an ion-exchange catalyst and a mercaptan as a co-promoter. This results in product in higher yields, which largely free from impurities thereby reducing the cost of purification.