Synthesis of methyl phenyl carbonate over TiO₂/SiO₂ catalysts

TiO₂/SiO₂ catalysts were prepared through precipitation-impregnation and used to catalyze the reverse disproportionation reaction of dimethyl carbonate (DMC) with diphenyl carbonate (DPC) to methyl phenyl carbonate(MPC). The catalysts were characterized by means of XRD, BET and NH₃-TPD. The effects of supports, TiO₂ loading, reaction temperature, reaction time, n(DMC):n(DPC) and catalyst dosage on the reverse disproportionation reaction were studied. The results indicated that the catalysts with good dispersivity of TiO₂ on the SiO₂ support, large specific surface area and large pore volume were obtained, which were beneficial to the diffusion of the reactants and product. When the TiO₂ loading was 15% (w), the best catalyst performance was achieved due to the highest weak acid amount on the catalyst surface. Under the optimal conditions of DPC dosage 0.35 mol, n(DMC):n(DPC)₃, w(15%TiO₂/SiO₂) 5% (based on the mass of DPC), reaction temperature 160℃, reaction time 2 h and stirring speed 500 r/min, the conversion of DPC and the yield of MPC reached 81.5% and 78.6%, respectively.