Preparation And Regulation Of RuPt Bimetallic Catalysts For Phthalates Hydrogenation

Phthalate is a kind of plasticizer which accounting for more than 60%of the total market.However,it binds to polyolefin plastic molecules through vander Waals forces,rather than chemical bonds.When the products are heated,phthalates can spread from the plastic to the environment,and causing cell cancer,toxic effects on human reproduction.Cyclohexane-di-formates have the same structure with phthalates.However,it is biodegradable,non-toxic and green.It has become the most suitable substitute for phthalates plasticizer.In this work,a series of Ru-based hydrogenation catalysts were prepared,the intermediate product and the route of hydrogenation reaction were studied with DOP as probe molecule.It was found that the liquid phase hydrogenation of DOP on Ru/AC catalyst is consecutive reactions and the hydrogenation of 4H-DOP is the control step of the yield.The second active metal components Ni,Pd and Pt were introduced to the Ru/AC catalyst.It was found that the bimetallic Ru Pt/AC catalyst is most active catalyst.According to the characterization results,well dispersed Ru Pt bimetallic nanoparticles were formed on the catalyst,and the strong interaction between the two metals resulted in the formation of Ru Pt alloy.It was found that Ru can donate electrons to Pt on Ru Pt alloy nanoparticles,leading to the formation of electron-deficient Ru which significantly promotes the hydrogenation rate of DOP and improves the selectivity to DEHCH by accelerating the further hydrogenation of intermediate products.The molar ratio of Pt and Ru was regulated,and it was found that the activity of catalyst reached the highest when the ratio of Pt to Ru is 0.6.The bimetallic Ru Pt_0.6/AC catalyst also presented excellent stability and versatility in the hydrogenation of phthalates,demonstrating its prospective future in the hydrogenation of aromatic ring contained compounds.Liquid phase dioctyl phthalate hydrogenation was studied over Ru/AC and Ru Pt_0.6/AC catalysts in a regime free of internal and external diffusion limitations.It is found that at 4.1-7.1 MPa,353-413 K DOP concentration has no influence on the hydrogenation rate of DOP,and the hydrogenation rate of DOP is proportional to the partial pressure of hydrogen.It provides ideas and theoretical support for the development of industrial catalysts for hydrogenation of phthalates.