Preparation Of Sulfated Zirconia By One Step Method And Its Catalytic Performance For Hydrogenation Of Biomass Derived Chemicals

Biomass is a renewable resource with abundant production.Furfural and levulinic acid are important biomass derived platform compounds.Furfural and levulinic acid can be converted to furfuryl alcohol andγ-valerolactone by catalytic transfer hydrogenation（CTH）reaction.Furfuryl alcohol andγ-valerolactone has broad application prospects in the synthesis of liquid fuels and fine chemicals.Because of the acid-base active sites that can synergistically catalyze CTH reactions,zirconium-based catalysts are widely used to catalyze hydrogenation reactions of compounds containing aldehyde-based biomass platforms.Sulfated zirconia is a solid acid catalyst.The Zr⁴⁺-O^2-in sulfated zirconia materials are Lewis acid sites and basic sites,respectively,and the water adsorbed on zirconium atoms is Br（?）nsted acid sites.The induction of S=O of the sulfate ion coordinated with Zr⁴⁺enhances the strength of Lewis acid sites and Br（?）nsted acid sites of sulfated zirconia compared to zirconia acid sites.In this paper,the sulfated zirconia material SZ-X（X is the S/Zr molar ratio in the material）was synthesized by a one-step solvothermal method using zirconium oxychloride as the zirconium source and manganese sulfate as the sulfating agent.The conventional sulfated zirconia preparation process involves the synthesis of zirconia followed by sulfuric acid impregnation,which generates a large amount of waste acid solution.The one-step solvothermal synthesis of sulfated zirconia proposed in this paper avoids the large amount of waste acid solution generated by the conventional two-step synthesis method due to the use of sulfuric acid impregnation step.The specific surface area of SZ-X and the intensity of acid-base sites can be effectively regulated by adjusting the addition ratio of Zr⁴⁺and SO₄^2-in the solvothermal synthesis solvent.The specific surface area and pore volume of the prepared SZ-0.2 reached370.5 m²/g and 0.22 cm³/g,respectively.based on XPS,NH₃-TPD,CO₂-TPD and contact angle tests,it was found that SZ-0.2 possessed acid-base active sites with higher content and intensity compared with Zr O₂.Also SZ-0.2 has good hydrophilic properties.Using isopropanol as the hydrogen donor,the SZ-0.2-catalyzed conversion of furfural at 120℃for 1 h yielded 96.6%furfuryl alcohol.Kinetic analysis showed that the Ea of SZ-0.2 catalyzed furfural reaction was 44.11 k J/mol.Using isopropanol as the hydrogen donor,the SZ-0.2-catalyzed conversion of levulinic acid at 130℃for 4 h yielded 96.1%γ-valerolactone.The substrate expansion experiments revealed that SZ-0.2still showed high catalytic activity in the CTH reaction of other carbonyl compounds such as 5-hydroxymethylfurfural,benzaldehyde,cyclopentanone,ethyl levulinate.