The transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC) was studied using tetrabutyl titanate and tetraphenyl titanate as catalysts. The main product was found to be methyl phenyl ca...The transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC) was studied using tetrabutyl titanate and tetraphenyl titanate as catalysts. The main product was found to be methyl phenyl carbonate (MPC) which is an intermediate of the reaction. The selectivity for DPC was improved when increasing the phenol/DMC molar ratio or prolonging the reaction time. The phenol conversion, selectivity for MPC and DPC were 47 4%, 90 9% and 9 14%, respectively, when the transesterification reaction approached equilibrium under the conditions of 175 ℃, 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 showed a higher catalytic activity than tetraphenyl titanate.展开更多
The chemical kinetics of the monoesterification between terephthalic acid(TPA)and 1,4-butanediol (BDO)catalyzed by a metallo-organic compound was studied using the initial rate method.The experiments were carried out ...The chemical kinetics of the monoesterification between terephthalic acid(TPA)and 1,4-butanediol (BDO)catalyzed by a metallo-organic compound was studied using the initial rate method.The experiments were carried out in the temperature range of 463-483 K,and butylhydroxyoxo-stannane(BuSnOOH)and tetrabutyl titanate[Ti(OBu)4]were used as catalyst respectively.The initial rates of the reaction catalyzed by BuSnOOH or Ti(OBu)4 were measured at a series of initial concentrations of BDO(or TPA)with the concentration of TPA(or BDO)kept constant.The reaction orders of reagents were determined by the initial rate method.The results indicate that the reaction order for TPA is related with the species of catalyst and it is 2 and 0.7 for BuSnOOH and Ti(OBu)4 respectively.However,the order for BDO is the same 0.9 for the two catalysts.Furthermore,the effects of temperature and catalyst concentration are investigated,and the activation energies and the reaction rate constants for the two catalysts were determined.展开更多
文摘The transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC) was studied using tetrabutyl titanate and tetraphenyl titanate as catalysts. The main product was found to be methyl phenyl carbonate (MPC) which is an intermediate of the reaction. The selectivity for DPC was improved when increasing the phenol/DMC molar ratio or prolonging the reaction time. The phenol conversion, selectivity for MPC and DPC were 47 4%, 90 9% and 9 14%, respectively, when the transesterification reaction approached equilibrium under the conditions of 175 ℃, 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 showed a higher catalytic activity than tetraphenyl titanate.
文摘The chemical kinetics of the monoesterification between terephthalic acid(TPA)and 1,4-butanediol (BDO)catalyzed by a metallo-organic compound was studied using the initial rate method.The experiments were carried out in the temperature range of 463-483 K,and butylhydroxyoxo-stannane(BuSnOOH)and tetrabutyl titanate[Ti(OBu)4]were used as catalyst respectively.The initial rates of the reaction catalyzed by BuSnOOH or Ti(OBu)4 were measured at a series of initial concentrations of BDO(or TPA)with the concentration of TPA(or BDO)kept constant.The reaction orders of reagents were determined by the initial rate method.The results indicate that the reaction order for TPA is related with the species of catalyst and it is 2 and 0.7 for BuSnOOH and Ti(OBu)4 respectively.However,the order for BDO is the same 0.9 for the two catalysts.Furthermore,the effects of temperature and catalyst concentration are investigated,and the activation energies and the reaction rate constants for the two catalysts were determined.
