Carbonylation of olefins by carbon monoxide and alcohols in the presence of Pd-complex catalytic system

Abstract

In order to develop new, efficient and environmentally friendly methods for the preparation of practically valuable esters of carboxylic acids, studies of the hydroalkoxycarbonylation reaction of a number of terminal olefins of normal structure (hexene-1, heptene-1, octene-1, nonene-1) with carbon monoxide and alcohols in presence of metal complex catalysts based on palladium phosphine complexes at low carbon monoxide pressures (≤ 20 atm).Two-and three-component systems based on PdCl2 and Pd(Acac)2, PdCl2(PPh3)2, Pd(PPh3)4 complexes containing a free ligand (PPh3) as a stabilizer and Bronsted acid (TsOH) as a promoter were studied as catalysts. It was shown that only the three-component systems PdCl2-PPh3-TsOH, PdCl2(PPh3)2-PPh3-TsOH, Pd(Acac)2-PPh3-TsOH, and Pd(PPh3)2-PPh3-TsOH have the highest catalytic activity in the studied reactions. It was found that the reaction of hydroalkoxycarbonylation of α-olefins proceeds with the formation of a mixture of linear and branched products. The influence of various conditions of the reaction (the ratio of the initial reagents and the components of the catalytic systems, temperature, CO pressure, duration) on the course of the process and on the yield of the target products was investigated. The optimal parameters of the studied reactions have been found.