Preparation And Catalysis Of Supported Palladium Nanoparticles Catalyst For Hydrogenation Of 2-tertiary Butyl Anthraquinone To Produce H₂O₂

In the thesis, Pd nanoparticles were prepared and supported on alumina to get supported Pd catalytsts. Catalysts were characterized by means of TEM, SEM, XRD, BET, UV, and on which the AQ reaction activity evaluation was performed.(l) Pd nanoparticles with an average diameter of 9 nm were prepared using the sol- gel method. PVP was introduced in the preparation in order to inhibit Pd nanoparticles agglomeration. The nanoparticles were supported on alumina to get supported catalystas. The catalyst was good at anti-sintered because the particles were distributed on the support. Lanthanide oxides were found to be effective promoters of the Pd catalyst.(2) The intrinsic kinetics for hydrogenation of 2-tertiary butyl anthraquinone over Pd/Al₂O₃ catalysts was studied at temperature from 318 to 333 K and hydrogen pressures from 0.1 to 0.4 MPa. The hydrogenation reaction of 2-tertiary butyl anthraquinone was carried out in a mixture medium, which consists of xylene and tributyl phosphate with the volume ratio of 3:1. An exponential model was employed to describe the reaction rate, and the kinetic parameters were obtained. The results show that the reaction rate is first order both for the concentration of 2-tertiary butyl anthraquinone and for hydrogen pressure. The apparent activation energy for hydrogenation is 34 kJ?mol?1.(3) Pd nanoparticles was prepared by the sol-gel method and then supported on alumina. A group of Pd-based catalysts were prepared with Ce, Pr, Nd, Sm and Dy as promoters. The results showed that the rare earth oxides are good promoters of Pd/Al2O3 for the reaction, and they can inhibit the growth of alumina crystals at high temperature, increase the catalyst surface area, improve the Pd dispersion and enhance the catalytic activity effectively. The promotion effect of the rare earth oxides on the catalytic performance of Pd/Al2O3 catalys for anthraquinone hydrogenation to H2O2 is in the order La > Nd > Pr > Sm >Dy> Ce.(4) Pure silicate KIT-6 was synthesized according to the well-established method. The large pore size of the KIT-6 mesoporous molecular sieve (～6nm) makes it possible for the Pd nanoparticles to be formed inside the KIT-6 channels as verified by the TEM image. Thus the nanosized particles can be readily impeded by the isolation of the channel walls. At the same time, the mesopores of KIT-6 are large enough for the diffusion and reaction of BAQ inside the KIT-6 channels. The characters of the pore structure of the mesoporous KIT-6 molecular sieve are important for its excellent catalytic behavior, Which leading to a high yield of H2O2. This novel Pd/KIT-6 catalyst shows an attractive perspective for industrial application.