TiO(acac)_2 Used as a Catalyst for Transesterification of Dimethyl Carbonate and Phenyl Acetate to Diphenyl Carbonate

Diphenyl carbonate(DPC) is considered as a substitution for phosgene to synthesize polycarbonates(PCs),and some methods are used for the synthesis of DPC,such as the transesterification of dimethyl carbonate(DMC) with phenyl acetate(PA),dimethyl carbonate(DMC) with phenol,and dimethyl oxalate(DMO) with phenol.In this prescript,the catalytic performance of some metal acetylacetonates and titanium compounds for transesterification of DMC with PA to DPC was measured and it was found that bis(acetyl acetonate) titanium oxide(TiO(acac)2) was a novel and efficient catalyst and it is testified that Ti was the catalytic center of the catalyst.When the reaction was carried out at 180 ℃,with a molar ratio of PA to DMC of 2∶1,a reaction time 4 h,a catalyst amount 0.6%(molar ratio to PA),the conversion of DMC was 74.9%,and the selectivity of DPC and MPC was 38.9% and 56.9%,respectively.Furthermore,a plausible mechanism for the transesterification of DMC and PA to MPC and DPC catalyzed by TiO(acac)2 was proposed by changing the feeding order of the materials and catalyst.