Chitosan as biosupport for the MW-assisted synthesis of palladium catalysts and their use in the hydrogenation of ethyl cinnamate

A novel catalytic system based on palladium supported on chitosan was synthesized adopting a MW-assisted process. This synthetic approach results efficient under mild reaction conditions and very short microwave irradiation times. The prepared catalyst was employed in the hydrogenation of ethyl cinnamate (EC) to ethyl hydrocinnamate (EHC) adopting both traditional heating and MW irradiation: this is the first study on this reaction which involves this type of catalyst. In addition, a one pot fully MW-assisted process which provides the synthesis of the Pd/chitosan catalyst and its direct use in the hydrogenation of ethyl cinnamate has been also studied. This one pot procedure assures fast reaction rate under mild reaction conditions avoiding the catalyst's isolation and purification, thus making easier the reaction scale-up. The achieved yields in the target product are particularly good and the system results completely recyclable, due to the stabilizing effect of the functionalized natural support toward the palladium particles. © 2013 Elsevier B.V. All rights reserved.