Insight into complexation of Pd-catalyst for methoxycarbonylation of ethene

The complexation of palladium with bidentate phosphine ligand has significant effects on the activity of the catalyst for methoxycarbonylation of ethene. Herein, the influence of the ratio of components, kind and sequence of additives, complexation temperature and time on the catalytic performance were studied, then probable mechanism was proposed, and further kinetic studies were carried out under the optimized conditions. Compared to add Methanesulfonic acid (MSA) after complexation, the addition of an appropriate dose of MSA in complexation rather than after complexation could effectively improve the activity of the catalyst, while the addition of Methyl Propionate (MeP) would reduce the activity of the catalyst. It was worth noting that the weak absorption of [Pd-H]+ in 1943 cm−1 was captured in the complex by in situ FT-IR, but it could not be found by normal FT-IR.