Heterogeneously catalysed selective hydrogenation reactions in ionic liquids

The selective hydrogenation of [small alpha],[small beta] unsaturated aldehydes has been performed in a range of room temperature ionic liquids. The reaction data reported show that it is possible to enhance the selectivity of supported palladium catalysts for the reduction of the conjugated C[double bond, length as m-dash]C bond by using ionic liquids as solvents compared with conventional molecular organic solvents. The catalyst system is easily recycled without the need to isolate or filter the catalyst and may be used without further treatment.