A new type of catalyst PdCl2/Cu-HMS for synthesis of diethyl carbonate by oxidative carbonylation of ethanol

A new type of catalyst, PdCl2/Cu-HMS, for diethyl carbonate (DEC) synthesis by oxidative carbonylation of ethanol in the gas-phase reaction was investigated. The modified support Cu-HMS which was synthesized using the neutral templating pathway at the room temperature kept its mesoporous structure even after it was calcined repeatedly at 550 °C for 3 h to remove the template. From XRD, XPS and ICP analysis, it can be concluded that copper incorporated into HMS frame and was highly dispersed in the frame of silica. Notably, the degree of order of mesoporous molecular sieves was improved in a certain extent after PdCl2 was loaded on Cu-HMS samples. The PdCl2/Cu-HMS catalyst exhibited excellent selectivity for DEC. The catalytic reaction mechanism was illuminated by the interaction between Pd2+ loaded on the surface and Cu2+ in Cu-HMS frame.