Strong Acid‐free Homogeneous Catalytic Systems for the Ester Products Synthesis by Alkenes Alkoxycarbonylation: Recent Advances

Abstract

Alkoxycarbonylation represents a method for the ester products synthesis from available reagents – unsaturated compounds, alcohols, and CO. The beginning of research on this reaction was laid in W. Reppe’ works in 1953. In early works, halides and carbonyls of Co, Ni, Rh, and Ir were used as catalysts, and alkoxycarbonylation was often complicated by the unsaturated compounds hydroformylation or alcohol carbonylation. In recent decades, in the presence of the most active and selective Pd‐phosphine systems with strong protonic acids, the products are typically only isomeric esters, which corresponds to the creating waste‐free production principles. At present, a large‐capacity synthesis process for methyl methacrylate, dubbed Alpha, is in operation, with the initial stage being ethylene methoxycarbonylation. In light of these developments, there is a growing interest among chemists and technologists in alkenes alkoxycarbonylation. The use of strong protonic acids as co‐catalysts is essential for the formation of active catalytic complexes. However, these acids are highly corrosive and can cause the alkenes isomerisation. This review is devoted to the analysis of acid‐free homogeneous Pd‐, Ru‐, Co‐, and Ni‐catalysts employed in alkenes alkoxycarbonylation over the past 15 years. As a result, polymers, monomers and other valuable linear and branched esters were obtained.