Silica-anchored organotin catalysts has been synthesized by a new synthetic scheme. It involves the synthesis of organotin-silane during the preparation of organotin using inorganic SnCl4 as tin precursor

which was then ahchored on the silicas for the transesterification of DMC with phenol to diphenyl carbonate. A series of silica supports containing different silanols were obtained by different preparations along with different treatments. TG and ICP characterizations showed that the Sn loading of the catalyst had positive correlation with the silanol content of the silica support. 29Si MAS NMR measurements indicated that the prepared catalysts possessed many T2 and T3 species

which was in favor of the stability. The more silanol the silica support contained

the more Sn the catalyst supported

and the more active the catalyst would be. Sn-MSiO2

the catalyst with the mesoporous silica support

exhibited the best catalytic performance: with a reaction temperature of 150—180℃ for 9 h

and a catalyst amount of 1.0 g

the phenol conversion and the transesterification selectivity reached 50.4% and 99.9%

respectively; in recycle test with a catalyst amount of 0.5 g

the phenol conversion decreased from 41.2% to 35.0% after five runs. Sn leaching was the main reason for the decline of catalytic activity.