Promotional Effect Of Surface Active Sites On Znic-modified Ru-based Catalyst In Benzene Hydrogenation And Alkylation

The utilization of cancerogenic benzene into value-added chemical feedstock is regarded as a promising strategy to improve the correlative environmental worries containing the effect of fuel quality on air pollution and emissions.Considering that cyclohexene is a potentially chemical material for the production of valuable nylons,caprolactam,and other fine chemicals,cyclohexene production from benzene selective hydrogenation is especially a desirable choice for the transformation of benzene Moreover,the oxidation of CHB to benzylic hydroperoxide and then the cleavage of this hydroperoxide for the production of cyclohexanone and phenol is a potential technology to produce phenol,which would take the replacement of cumene in phenol production.In addition,the intermediate product cyclohexene in the process of benzene hydroalkylation has an important influence on the yield of cyclohexylbenzene,and it is also an important organic chemical raw material.Cyclohexylbenzene is an additive for battery electrolytes with excellent performance.Both of these substances have great industrial prospects.However,both of them still face the problem that the side reaction of excessive hydrogenation of benzene is difficult to control in the research and application.Based on LDHs precursors,a series of zinc-modified high-efficiency Ru-based catalysts were constructed in this paper.The contribution of Zn to the electronic state of Ru and the adjustment of the acid-base and hydrophilicity of the catalyst surface was investigated,and the selective hydrogenation of benzene was studied.Performance impact.At the same time,it is advancing to mix aβmolecular sieve catalyst with abundant acid sites to construct a highly efficient Ru-Zn bifunctional catalyst,and to study the influence of different acid sites on the alkylation performance.main tasks as follows:（1）A series of Ru/LZA-x catalysts with good hydrophilicity were prepared by co-precipitation method.Zn was introduced into the catalyst carrier in a heterogeneous form,which increased the content of Ru^δ+on the catalyst surface and blocked the continuous strong hydrogenation active sites.The exposure of Ru⁰weakens the adsorption of cyclohexene on the surface of the catalyst,and at the same time increases the content of acidic sites in the carrier,which promotes the adsorption of benzene molecules.The double improvement of hydrogenation activity and semi-hydrogenation selectivity was realized,and the highest yield reached 43.2%.The material does not require any additives,and solves the shortcomings of equipment corrosion,dirt,and difficult separation caused by traditional homogeneous zinc additives.（2）Based on the results of selective hydrogenation experiments,a Ru-Zn hydrogenation catalyst was prepared,combined with different commercial molecular sieves through mechanical mixing,and used the difference in molecular sieve pore size and acidic sites to form a series of mixed molecular sieve Ru-Zn Dual-function catalyst.The balance between metal active centers and acid centers was adjusted,βmolecular sieve with suitable pore structure and acidic sites,which achieved excellent performance in the benzene hydroalkylation reaction.At the same time,the reaction conditions of the benzene hydroalkylation reaction are investigated using batch reactors,fixed-bed reactors and other reaction devices,and better industrial production conditions are obtained.