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.