Effect of Mg2+ additives on Nieuwland catalyst: The role of the second metal ionic radius

In the production of chloroprene rubber, acetylene dimerization over the Nieuwland catalyst is an important step. The addition of Mg2+ to the Nieuwland catalyst improves the acetylene conversion and the selectivity toward vinyl acetylene. In this study, active component crystal structure, the role of Mg2+ in the Nieuwland catalyst, the reason for the catalyst deactivation, and the reaction mechanism were analyzed by different characterization techniques. The results indicate that the main reason for the Nieuwland catalyst deactivation is the loss of Cu2+. The addition of Mg2+ will increase the exposure of active sites, reduce the residence time of acetylene in the catalyst, and inhibit the reduction of Cu2+, thereby improving the catalytic performance and stability of the catalyst.