Metathesis reactions of rapeseed oil-derived fatty acid methyl esters induced by monometallic and homobimetallic ruthenium complexes

Abstract

In this study, homobimetallic ruthenium alkylidene complexes were used for the self-metathesis and ethenolysis reactions of methyl oleate and rapeseed oil-derived FAME mixtures. The activity and selectivity of homobimetallic ruthenium alkylidene complexes were also compared with their monometallic analogs. It has been determined that homobimetallic complexes bearing phosphine and N-heterocyclic carbene ligands are more active and selective catalysts than their monometallic analogs for self-metathesis and ethenolysis reactions of rapeseed FAME mixture. Homobimetallic ruthenium complexes showed superior selectivity at 25°C toward these reactions. Conversion values of 99% with 96% selectivity toward ethenolysis products were observed by using homobimetallic ruthenium complexes. In addition to these superiorities, relatively lower amounts of double bond isomerization side-products were obtained by using homobimetallic complexes. This catalytic approach represents a unique example for metathesis transformation of FAME mixtures at relatively low temperature (25°C) and ethylene pressure (1atm) with high selectivity using homobimetallic ruthenium alkylidene complexes.