CuCl2和HY分子筛的表面反应及Cu/Y分子筛的制备及其催化甲醇氧化羰基化

以CuCl₂为前驱物与HY分子筛进行固相离子交换制备了Cu/Y催化剂，采用热重方法研究了CuCl₂与HY分子筛的表面固相离子交换反应，结合活性测试表明催化剂中高度分散的CuCl和离子交换形式的Cu⁺物种是甲醇氧化羰基化合成碳酸二甲酯的催化活性中心。X射线光电子能谱表征和元素分析结果表明，活性金属Cu主要以CuCl形式存在于分子筛外表面，而在分子筛笼内则以交换的Cu⁺和少量吸附的CuCl形式存在。与以CuCl为交换铜源所制催化剂相比，以CuCl₂为铜源制备的催化剂Cu含量低，催化活性更高。

Surface reactions of CuCl2 and HY zeolite during the preparation of CuY catalyst for the oxidative carbonylation of methanol

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.