Siberian Federal University

The influence of the reduction modes of polynuclear Pd (II) hydroxides deposited on carbon support Sibunit on catalytic activity in the reductive debenzylation and a possibility of recycling the catalysts were studied. It was found that in the presence of molecular hydrogen the optimum conditions of formation of nanosized metallic palladium particles on the surface of the carbon support are reduction of polynuclear Pd (II) hydroxides until 250 °C with temperature ramp 1.5 °C per minute providing the greatest activity and stability in the reaction hydrodebenzylation-acylation. The possibility to stabilize the active sites of Pd during Pd (II) reduction by a “wet method” through introduction of III, IV and V groups elements, coming from the corresponding reducing agents such as hydrazine hydrate, sodium formate and sodium tetrahydroborate was investigated. Physico-chemical methods of low-temperature nitrogen adsorption, chemisorption of CO, XPS, EXAFS and XANES were applied to study the formation of the active Pd component in the presence of a reducing modifier and to determine the composition of the most active phase. It is shown that as a result of the heteroatom introduction the order in crystallinity decreases in the order: PdN> PdC> PdB while catalyst stability increases in the opposite way. It is found that Pd-B compositions presumably representing metallic palladium glasses are the most stable catalysts for the synthesis of 4,10-dibenzyl-2,6,8,12-tetraacetyl 2,4,6,8,10,12-hexaazaisowurtzitane.