Modification And Characterization Of A L Iquid Phase Selective Hydrogenation Nickel Catalyst

Catalytic hydrogenation in liquid phase can be considered as the most important catalytic method in synthetic organic chemistry of fine chemical. To improve its green degree has important research and application value and one of the most effective ways is to achieve a heterogeneous catalytic system. The classical hydrogenation catalysts for preparative hydrogenation are heterogeneous catalyst of Pd or Pt, which are costly and are poor selectivity for certain over-hydrogenation reaction. To solve these problems, this paper attempts to introduce a non-metallic element P and Rare Earth Elements Ce to the preparation of Ni-based catalyst, the structure and physicochemical properties of the catalyst is regulated by modulating binary or ternary preparation system elements. And easy excess alkyne hydrocarbons such as benzene hydrogenation of acetylene hydrogenation reaction as a pointer to explore the selective catalytic hydrogenation catalysts prepared?selectivity to alkene? performance, which found a correlation sample composition, structure, catalytic properties the impact of laws and screened create a good catalytic performance for ASP Ni-based catalysts.1. First to?NH₄?₂HPO₄ as a source of P and Ni salt precipitating agent, the usual bases such as Na OH or NH₃ ? H₂ O as Ni salt and salt Ce co-precipitating agent, by former hydrothermal synthesis reaction and subsequent heat treatment and pretreatment were prepared Ni-P and Ni-Ce two series of binary catalyst, XRD and XPS tests show that Ni-P catalyst body are all prepared Ni2 P phase, at atmospheric pressure hydrogenation of phenylacetylene little effect, and when the hydrogen pressure regulator when 0.6MPa can gain 30-40% conversion rate, selectivity to styrene of more than 90% available; Ni-Ce catalyst prepared according to comparative composition can form a composite structure of Ni-Ce or CeO₂ supported Ni catalyst, These two types of catalysts having a certain conversion of phenylacetylene hydrogen under normal pressure, best up to 70% conversion, but low selectivity. These results indicate that the introduction of P formed Ni₂P phase is expected to improve the selectivity of Ni-based catalysts liquid alkyne hydrogenation of olefins, which is characterized by the introduction of Ce improve atmospheric conditions Ni-based catalysts activated conversion efficiency of phenylacetylene.2. Preparation of experiments and reaction binary catalyst discovery as the basis for the preparation and characterization of Ni-P-Ce ternary catalyst design. The point is that?NH₄?₂HPO₄ as a source of P and Ni salt and salt Ce co-precipitating agent, through modulation Ce: Ni molar ratio was prepared a series of three-way catalyst. By the XRD and XPS tests show that when the Ce: Ni molar ratio is controlled to an appropriate range?0.05 to 0.2?, the catalyst exhibits prepared to Ni₂P as the base, the surface confinement distribution Ce₂O₃-CeO₂ thin catalytic interface of Ni-P-Ce three-yuan catalyst, at atmospheric pressure achieve phenylacetylene conversion efficiency of more than 90%, while the yield of styrene can also generate up to 90%, which received excellent catalytic performance of the new Ni-P-Ce Ni-based ternary structure catalyst. Cheap green new catalysts for the creation of these results can be used in liquid phase hydrogenation reactions provide reference and basis.