Influence of Phosphorus Modifier and Nature of the Support on the Properties of Palladium Catalysts in the Chemoselective Hydrogenation of Acetylenic Compounds

Abstract

Efficient heterogeneous catalysts for the chemoselective hydrogenation of terminal and disubstituted alkynes and alkynols to monoenes based on Pd–P particles have been proposed. The influence of a zeolite support (Na-ZSM-5, MCM-41) and a phosphorus modifier on the properties of palladium catalysts in the semihydrogenation of acetylenic compounds is considered. It has been shown that promotion with phosphorus increases the activity of palladium catalysts in the hydrogenation of various acetylenic compounds from 2.5 to 30 times without reducing the selectivity for monoenes. High selectivity for monoenes is determined by both thermodynamic and kinetic factors. Using the example of the acetylenic alcohol hydrogenation the possibility of changing the ratio of hydrogenation rates of triple and double bonds as a result of varying the solvent nature and the structural order of the catalyst particles was demonstrated.