Design And Preparation Of Palladium And Platinum-Based Catalysts And Their Application In Reductive Amination Of Biomass-Derived Oxygen Compounds

Biomass is an inexpensive and abundant renewable carbon resource with the advantage of“Net Zero Carbon Emission”for conversion and utilization.Making full use of biomass resources to replace fossil resources to produce high-value chemicals,fuels and functional materials is of great significance to resource security and environmental protection.In this thesis,the preparation of nitrogen-containing functional molecules from biomass oxygen-containing derivatives such as aromatic ethers and 2,5-hexanedione was investigated by designing efficient Pd and Pt catalysts for the controlled conversion of biomass to high-value chemicals.The main research contents and innovations are as follows:1.Hf⁴⁺exchange montmorillonite loaded Pd nanoparticle catalyst（Pd/Hf-MMT）was designed to study the reductive amination reaction of aromatic ethers（especially lignin model compounds）with amines,and the effects of reaction temperature,molar ratio of ether to amine and H₂ pressure on the reactivity and product selectivity were investigated.It was found that Pd/Hf-MMT could efficiently catalyze the conversion of various aromatic ethers to prepare cyclohexyl-substituted amines under low H₂ pressure（0.3 MPa）and without homogeneous acid additives.Systematic studies have shown that the high activity of Pd/Hf-MMT originates from the synergistic effect of the high electronegativity of Pd particles and the strong acidity of Hf-MMT carrier.2.Cerium dioxide loaded Pt nanoparticle catalytic materials（Pt/CeO₂）were designed to study the reductive amination reaction of cellulose platform compound 2,5-hexanedione with amines,and the effects of reaction temperature,catalyst properties,and H₂ pressure on the reaction activity were investigated.It was found that Pt/CeO₂ was able to catalyze the reductive amination reaction of 2,5-hexanedione with various organic amines with high selectivity for the synthesis of N-substituted tetrahydropyrroles at low temperature（30℃）.Systematic studies showed that the high activity of Pt/CeO₂ originated from the synergistic effect of acid-base site of support,Pt⁰,and conversion between Ce³⁺and Ce⁴⁺.