A novel catalytic material

ultrafine silica embedded catalyst

was prepared through the hydrolysis of tetraethoxysilane (TEOS) in W/O microemulsion

which was composed of cyclohexane

polyoxyethylene (10) nonylphenyl (NP-10)

hexanol and aqua ammonia of PdCl2 and Cu(OAc)2.It was found that the active species was wholly or partly embedded in the spherical silica particles with diameters in the range of 40—120 nm.The catalytic behavior of the catalyst in oxidative carbonylation of phenol to diphenyl carbonate (DPC) was studied. Under the optimized conditions(80℃，3.9 MPa and 8 h)

the yield of DPC was 35.4%. In comparison with the catalysts prepared by the impregnation and sol-gel method

the ultrafine embedded catalyst showed high activity and long service time.When the catalyst was used at 80 ℃，3.9 MPa and 4 h for 4 times

the yield of DPC was 25.2%

16.5%

14.5% and 13.4%

respectively.