Deactivation phenomena of MoO3/SiO2 and TiO2/SiO2 during transesterification between dimethyl carbonate and phenol Original Research Article

The catalytic stability of MoO3/SiO2 and TiO2/SiO2, which have been reported to be active for transesterification between dimethyl carbonate and phenol, was examined in a batch reactor for the same reaction. X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and the temperature programmed oxidation (TPO) were conducted to characterize the catalysts. The gradual decrease in the activity was observed over both catalysts with increasing the number of a batch reaction. The strong adsorption of reactants was observed from the temperature programmed oxidation experiment. The deactivated MoO3/SiO2 can be regenerated after oxidation in air at 823 K. However, the deactivated TiO2/SiO2 can be only partially regenerated even after oxidation in air at 973 K. Some of the Mo species in MoO3/SiO2 were leached out during a reaction. This dissolved homogeneous Mo species appeared to take part in this reaction.