Application Of Zirconium Organic-inorganic Composites And Nickel-iron Hydrotalcite Catalysts In Hydrogenation Reaction

Nowadays,human beings rely heavily on energy to promote social development and scientific and technological progress.More than 85%of them are fossil energy.Fossil energy is non-renewable and its combustion has caused many adverse effects on the environment,such as greenhouse effect,water pollution and acid rain.Biomass resource has become an ideal substitute for fossil energy because of its renewability,cleanliness and wide distribution.Therefore,the development and utilization of biomass resources has become a research hotspot.Biomass can be converted into various platform chemicals under the action of appropriate catalysts,and then into various functional small molecules.Furfuryl alcohol?FOL?and?-valerolactones?GVL?are two of them.FOL can be used to produce resins,synthetic fibers,pesticides,adhesives and fine chemicals.GVL can be used as green solvents,fuel additives and intermediates for fine chemicals synthesis.Therefore,it is of great research value and practical significance to explore highly efficient and environmentally friendly catalysts for the conversion of platform chemicals to these functional small molecules.Firstly,Zr-thiophenedicarboxylate hybrid catalysts?DUT-67?Zr?,DUT-68?Zr?and DUT-69?Zr??were prepared by simple solvothermal method,and the structure and morphology of the catalysts were investigated by various characterization methods.Then,the optimum catalysts were selected and the optimum reaction solvents were found out.The reaction time,reaction temperature and catalyst dosage were investigated.The effect of catalytic activity on the reaction was studied and the optimum reaction conditions were found.The optimum reaction conditions for 1mmol furfural?FAL?catalyzed by DUT-69?Zr?in 5 mL 2-propanol are 0.1 g DUT-69?Zr?,120?and 4 h.Under these conditions,the conversion of FAL and the yield of FOL are 95.9%and 92.2%,respectively.The heterogeneity and recyclability of the catalyst were proved by thermal filtration and recyclability experiments.The stability of the catalyst was further investigated by comparing the characterization of the catalyst after six cycles with that of the initial catalyst.Based on the synergistic catalysis of acid site(Zr⁴⁺)and basic site(O^2-),a possible reaction mechanism was proposed.DUT-69?Zr?was applied to the hydrogenation of other carbonyl compounds to explore its universality.Three hydrotalcite catalysts?Ni-Fe?2/1?LDH,Ni-Fe?3/1?LDH and Ni-Fe?4/1?LDH?with different molar ratios of nickel to iron were synthesized by simple hydrothermal method and applied to the preparation of FOL from FAL.In this paper,the structure and morphology of catalysts were investigated by various characterization methods.The effects of catalyst type,solvent type,reaction time and reaction temperature on the catalytic activity were investigated,and the optimum reaction conditions were found.The optimum reaction conditions for 1 mmol FAL catalyzed by Ni-Fe?3/1?LDH in 5 mL 2-propanol are 0.2 g Ni-Fe?3/1?LDH,140?and 5 h.Under these conditions,the conversion of FAL and the yield of FOL are 97%and 90.2%,respectively.In this paper,the heterogeneity of the catalyst system and the recyclability of the catalyst were proved by the thermal filtration and recyclability experiments of the catalyst respectively.The stability of the catalyst was further investigated by comparing the characterization of the catalyst after five cycles with that of the initial catalyst.Based on the synergistic catalysis of acidic sites(Ni²⁺and Fe³⁺)and basic sites?-OH?,a possible catalytic mechanism was proposed.Ni-Fe?3/1?LDH was applied to the hydrogenation of other carbonyl compounds to study its universality.Mesoporous silica was synthesized by hydrothermal method and calcination method.Then zirconium triethylamine was grafted onto the silica hydroxyl bond of mesoporous silica.Composite catalysts with different zirconium content?H-Zr-TM,Zr-TM and D-Zr-TM?were synthesized by changing the amount of zirconium source.The reaction of preparing GVL by ethyl levulinate?EL?was carefully studied.The structure and properties of the catalysts were analyzed by a series of characterizations.Then the conditions were optimized to find the best reaction conditions.The optimum reaction conditions for the preparation of GVL by 1 mmol EL catalyzed by Zr-TM in5 mL 2-propanol are 0.2 g Zr-TM,150?and 12 h.Under these conditions,the conversion of EL and the yield of GVL are 97%and 90.2%,respectively.In this paper,the heterogeneity and recyclability of the catalyst were proved by thermal filtration and recyclability experiments.Based on the synergistic catalysis of acidic site(Zr⁴⁺)and basic site(N and O^2-),a possible catalytic mechanism was proposed.Zr-TM catalyst was applied to the hydrogenation of other levulinic acid and its esters.It was found that it had good universality.In conclusion,three clean and inexpensive catalysts have been developed with two biomass-based platform compounds as reactants,which have good selectivity for high-value target chemicals,and have important theoretical significance and potential application value for the catalytic conversion and development of biomass platform compounds.