Transesterification of dimethyl carbonate and phenol with titanate catalysts

The transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC) was studied using tetrabutyl. titanate and tetraphenyl tita nate as catalysts. The main product was found to be methyl phenyl carbonate (MPC) which is an intermediate of the reaction. The selectivity for DPC wa s improved when increasing the phenol/DMC molar ratio or prolonging the rea ction time. The phenol conversion, selectivity for MPC and DPC were 47.4%, 90.9% and 9.14%, respectively, when the transesterification reaction approa ched equilibrium under the conditions of 175 degreesC, 25 h and DMC: phenol : Ti(OBu)(4) molar ratio of 1.5:1:0.05. The selectivity for DPC could reach 12.2% when the reaction time was 30 h. The tetrabutyl titanate catalyst sh owed a higher catalytic activity than tetraphenyl. titanate.