CuNaY分子筛的制备及其催化甲醇氧化羰基化

采用多种铜盐溶液与NaY分子筛离子交换制备了CuNaY催化剂,通过加入氨水提高溶液pH值以及高温活化,显著提高了该催化剂对甲醇氧化羰基化合成碳酸二甲酯的反应活性。不同的铜盐水溶液交换制备的CuNaY催化剂催化活性不同,添加氨水将溶液pH值调节为11后,离子交换制备的CuNaY催化剂的催化活性和DMC选择性明显升高且趋于一致。经元素分析、XRD、XPS和H₂-TPR表征可知,加入氨水可促进Cu²⁺离子交换的进行,提高CuNaY催化剂中Cu的交换量,催化剂中约75%的Cu²⁺定位于分子筛的超笼中。

Preparation and catalytic activity of CuNaY zeolite in oxidative carbonylation of methanol

Ammonia was added to the ion-exchange solution to adjust the pH in the preparation of CuNaY catalyst by ion-exchange of NaY zeolite with Cu²⁺ aqueous solution, and then the ion-exchanged CuNaY was activated by high temperature calcinations. The effect of anion type in the Cu²⁺ aqueous solution on the ion-exchange process and catalytic performance of the catalyst were studied, it is shown that the catalytic activity of CuNaY ion-exchanged of NaY with aqueous solution of copper salts was low, when the pH of ion-exchange solution was adjusted to 11 by adding ammonia, the catalytic activity and selectivity of DMC increased greatly. Based on the characterization of the microstructure of the catalyst by elementary analysis, XRD, XPS and H₂-TPR techniqs, it is shown that by adding ammonia into the ion-exchange solution, the ion-exchanged reaction is promoted, resulting in the increase of the ion-exchanged Cu²⁺, 75% of the Cu²⁺ in the catalyst located in the supercages of the Y zeolite.