Palladium acetylacetonate dissolved in 1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid catalyses the selective two-phase hydrogenation of conjugated and non-conjugated (functionalized and non-functionalized) dienes into the respective monoenes. The system does not require the use of organic solvents, the products are removed by simple decantation or distillation and the recovered ionic catalytic solution can be reused several times without any significant changes in its catalytic activity and selectivity.
biphasic hydrogenation; ionic liquids; dienes; palladium catalysts