Preparation Of Ni-based Catalysts And Study On Catalytic Hydrogenolysis Of Aryl Ether Bonds

In recent years,Chinese oil import volume ranks first in the world,the consumption of oil imports is huge,and the foreign dependence rate is too high.The upgrading and utilization of low-rank coal and lignin depolymerization to produce biofuels and high value-added petrochemicals are effective ways to ensure the safety of my country’s petroleum and fossil energy reserves.Based on this background,it is necessary to develop hydrogenolysis catalysts that can efficiently and directionally convert aryl ether model compounds containing C–O bonds.In this paper,Ni NPs,Ni-Ru BNPs,and Ni-Ru/HZSM-5 catalysts were prepared in an orderly manner by using Ni with high catalytic activity in non-precious metals as sacrificial precursor and Ru with high hydrogenolysis activity in precious metals as noble metal components,and using commercial HZSM-5 molecular sieve as acidic support.Which are used in the hydrodeoxygenation of C–O bond aryl ethers.The main research contents and results are as follows:（1）Ni NPs catalysts were first prepared by ultrasonic liquid-phase reduction method,and then Ru was replaced on the surface of Ni NPs by galvanically coupled displacement method,and Ni-Ru BNPs catalysts with different molar ratios were obtained.The research shows that the Ni catalyst prepared with hydrazine hydrate as the reducing agent is an elemental substance,which is irregular spherical and has an average particle size of 60 nm.The Ni-Ru catalyst was obtained by replacement.Ru was uniformly dispersed on the surface of the Ni particles,forming a contact state in close proximity,and the particle morphology and particle size did not change significantly.The specific surface area and pore size are increased.There is a synergistic effect of Ru Ni bimetals,electrons are transferred,and electron-deficient Ru and surface electron-enriched Ni are formed,which is beneficial to the hydrogenolysis reaction.（2）The hydrogenation of the unsaturated bond of the model compound occurs on the surface of the active metal,while the hydrogenolysis reaction to remove the heteroatom occurs on the surface of the acidic support.Therefore,in this paper,commercial HZSM-5 molecular sieve is used as the acidic carrier,and the pre-prepared HZSM-5 molecular sieve is loaded by the liquid phase adsorption method.metal nanoparticles to obtain highly active and highly selective Ni-Ru/HZSM-5 catalysts.The research shows that the pore characteristics and framework structure of the support did not change significantly after loading the active metal components.The catalyst retains the changing trend of the binding energy of the metal catalyst,but due to the introduction of the carrier,the surface Ni is enriched and some metal components are adsorbed into the pores of the carrier,resulting in the increase of the surface Ni/Ru.The original L acid and B acid acid sites in the carrier are retained,and the medium and strong acid acidity and strong acid acidity are enhanced,which is conducive to breaking the C–O bond.（3）In this study,diphenyl ether（DPE）with a higher dissociation enthalpy of C–O bond was used as a probe compound for the catalytic hydrogenolysis reaction.The optimal catalyst and optimal conditions were screened out,and the possible catalytic hydrogenolysis reaction path and mechanism of CMC were proposed.The optimal catalyst,p-benzyl phenyl ether（BPE）,diphenyl ether（BPE）and catalytic hydrogenolysis of various aromatic ether CMCs containing typical C–O bridges,such as benzyl ether（DBE）.The results showed that DPE can be completely converted into Ben.（Y:47.24%）,CHX（Y:22.75%）and a small amount of hydrogenation products under the reaction conditions of 250 ^oC,6 bar H₂+4 Bar N₂and 0.1mmol Ni NPs in 1 h.DPE can be completely converted into Ben.（Y:47.83%）,CHX（Y:19.41%）and a small number of hydrogenation products under the reaction conditions of 250^oC,6 bar H₂+4 Bar N₂and 3.0 mg Ni₁₉-Ru₁BNPs in 1 h.DPE can be completely converted into Ben.（Y:78.33%）and CHX（Y:2.89%）under the reaction conditions of 250 ^oC,2 bar H₂+8 Bar N₂and 0.06g 40 wt%Ni₁₉-Ru₁/HZSM-5 in 1 h.The results of suitability of catalysts showed that both metal catalysts and supported catalysts had better catalytic activity for hydrohydrolysis of a variety of aryl ether CMCs containing C–O bonds.