Abstract:

A Cu^I/Y catalyst was prepared for the vapor phase oxidative carbonylation of methanol to dimethyl carbonate (DMC). The surface solid-state interactions of CuCl₂ with HY zeolite were studied using thermogravimetry. The surface properties and morphologies of catalyst samples were analyzed by thermogravimetry, X-ray photoelectron spectroscopy, and elemental analysis, and their catalytic performance was assessed in a fixed-bed reactor. Both CuCl and CuCl₂ were found to co-exist on the external surface of the catalyst, while ion-exchanged Cu^Ι along with small amounts of adsorbed CuCl were contained in the internal Y zeolite cage structures. Both the CuCl and CuCl₂ were active species during the DMC synthesis. Compared with a conventional Cu^I/Y catalyst prepared by heating a mixture of CuCl and HY zeolite, the Cu^I/Y catalyst prepared by heating a mixture of CuCl₂ and HY zeolite showed increased catalytic activity for the oxidative carbonylation of methanol, even though it had lower Cu and Cl contents.

Key words: Copper chloride, Solid-state ion exchange, Oxidative carbonylation, Methanol, Dimethyl carbonate