Development of Efficient Ru/Deep Eutectic Solvent Catalytic System for Alkoxycarbonylation of Alkene without Acid Additives

Graphical We developed a highly active and selective Ru/DES catalytic system for the alkoxycarbonylation of alkenes under mild conditions without strong acid additives. Conversion of 1-hexene reached 99.0 % at 1 MPa CO with 99.1 % ester selectivity. Notably, Ru/DES outperformed Ru 3 (CO) 12 . The excellent performance originated from [Ru(CO) 2 Br 3 ] − produced through Ru 3 (CO) 12 dissolution and coordination with DES. The catalytic alkoxycarbonylation of alkenes is an attractive, atom-efficient method for producing value-added carboxylic esters. However, the conventional catalyst system for this reaction needs coordination with a noble metal, sensitive ligands and proton acid additives. Therefore, the design of a simple and efficient catalyst system without any acid additives under mild conditions is still a major challenge. In this work, a simple ruthenium/deep eutectic solvent catalytic system was developed to effectively catalyse the alkoxycarbonylation reaction without any sensitive ligands or acid additives under mild conditions. The conversion of 1-hexene reached 99.0 %, and the ester selectivity was 99.1 %, much higher than that of Ruthenium carbonyl without deep eutectic solvent. The excellent performance of the catalytic system could be ascribed to the form of the ruthenium active species [Ru(CO) 2 Br 3 ] − in the deep eutectic solvent. This innovative catalyst system presents a significant advancement in the alkoxycarbonylation reaction, eliminating the use of acid additives and delicate ligands.