Novel Hybrid Palladium Catalysts on Substrates of γ-Aluminum Oxide and Hyperbranched Polyaminoethylene Carbonates of the Second and Third Generations

New hybrid palladium catalysts on substrates of γ-aluminum oxide and hyperbranched polyaminoethylene carbonates of the second and third generations have been synthesized. The catalysts were synthesized in several stages, firstly modification of γ-aluminum oxide with dimethyl carbonate was carried out. In the second stage, hybrid composites were synthesized by reaction of modified γ-aluminum oxide with hyperbranched polyaminoethylene carbonates of the second and third generations. In the next stage, palladium complexes were obtained by reacting the hybrid composites with palladium chloride. The structures and spherical morphologies of the particles of the obtained compounds were confirmed by infrared spectroscopy (IR), X-ray diffraction analysis (XRD), confocal laser scanning (CLSM) and optical microscopy. The pore characteristics of the Pd(II) complexes were determined by nitrogen adsorption/desorption. Pd(II) palladium complexes reduced in hydrogen flow to Pd(0) nanoparticles were utilized in the selective hydrogenation reaction of α-methylstyrene to cumene. The hybrid palladium catalysts on second and third generation γ-aluminum oxide and hyperbranched polyaminoethylene carbonate substrates showed high catalytic activity with activation energies E_a = 45.2 and 46.3 kJ mol^–1 in the temperature range from 43 to 73℃ and atmospheric pressure. The results indicate promising applications of the new hybrid catalysts for the hydrogenation of unsaturated compounds.