Synthesis Of Levulinic Acid Esters Catalyzed By Novel Solid Sulfonic Acid

Solid acid catalyst has the advantages of good environment,easy separation and reusable.With the highlight of energy and environmental problems,the transformation of renewable biological resources into bio-energy,biochemicals and biomaterials such as biomass carbon acid catalyst has become a hot topic in the 21 st century.Using various types of biomass,especially agricultural and forestry waste and other raw materials as carbon sources,to prepare biomass carbon sulfonic acid catalyst with excellent performance in the acid catalyzed reaction has attracted much attention in the past decade in the field of catalysis.5-sulfosalicylic acid in the presence of phenolic hydroxyl,carboxyl and sulfonic acid functional groups,and biomass carbon sulfonic acid catalyst had the same acid catalytic activity center.The catalytic activity of 5-sulfosalicylic acid catalyzed synthesis of levulinic acid esters was investigated,which provided a reference for the subsequent experiments on the catalytic performance of lignin in this paper.The results showed that 5-sulfosalicylic acid had a good catalytic effect in the synthesis of levulinic acid esters,showing the possibility that the solid carbon sulfonic acid catalyst had a good catalytic effect in the levulinic acid ester synthesis reaction.A new montmorillonite lignin sulfonic acid catalyst was prepared by carbonization and sulfonation using montmorillonite and lignin in papermaking black liquor as raw materials,and the catalytic performance of the catalyst was investigated by esterification of levulinic acid with n-butanol as a probe in this thesis.The results showed that reaction time was 3 h,the amount of catalyst was 8% of the mass of levulinic acid,the molar ratio of butanol to levulinic acid was 1.4:1,the amount of dehydrant cyclohexane was 8 mL,and the conversion of levulinic acid was 76.1%,and the conversion was still up to 57% after 7 times reuse of the catalyst under these conditions.The conversion rate of levulinic acid in the probe reaction was still to be improved under the optimized conditions due to the low sulfonic acid content of montmorillonite lignin sulfonic acid catalyst.The acid content was increased after the preparation method of catalyst has been improved in the fourth chapter,and the modified catalyst greatly improved the conversion of levulinic acid in the synthesis of butyl levulinate.The conversion of levulinic acid was almost 100%,and the conversion of levulinic acid was still 86.1% after 9 times of repeated use of the catalyst under optimal reaction conditions.The response paths and possible mechanisms were explored initially in this thesis.