Transfer hydrogenolysis of aromatic ethers promoted by the bimetallic Pd/Co catalyst

Abstract

The transfer hydrogenolysis of lignin derived aromatic ethers (benzyl phenyl ether, phenethyl phenyl ether and diphenyl ethers) have been investigated by using the coprecipitated Pd/Co as heterogeneous catalyst and 2-propanol as H-donor/solvent. A quantitative conversion of benzyl phenyl ether into toluene and cyclohexanol was obtained after 180 min at 240 °C. The bimetallic Pd/Co catalyst is, by far, more efficient if compared to commercial Pd/C and Co-based catalytic systems showing, at the same time, a good reusability. The enhanced ability in the CO bond cleavage in aromatic ethers is related to the formation of bimetallic Pd-Co ensembles, arisen from the preparation procedure adopted, as confirmed by a complete physico-chemical characterization that includes XRD, SEM, TEM, H2-TPR, XPS and EXAFS analysis.