Preparation Of High Value-added Chemicals By Catalytic Hydrogenation Of Biomass-derived Acid Over Supported Catalyst

Conversion of renewable and resource-rich biomass to commodity chemicals and fuels has received significant attention for it holds the possibility for carbon neutral technologies as an efficient way to solve current problems such as energy crisis and environmental problems. Through catalytic hydrogenation of biomass-derived acid, lots of high value-added chemicals, mainly polyols and ethers compounds, can be obtained, which can be widely used in modification of liquid fuel, the synthesis of new materials, food additives, pharmaceutical researches and other important areas. Research on the catalytic hydrogenation of biomass-derived acid to high value-added chemicals has been a hotspot home and abroad.This study is meant to investigate the selective hydrogenation of itaconic acid to high value-added chemicals, such as 2-methyl-1,4-butanediol,3-methyl-tetrahydrofuran and 2-methyl-y-butyrolactone and 3-methyl-y-butyrolactone. The hydrogenation of biomass-derived acid over noble metal supported catalysts were mainly studied in this paper. Palladium catalysts, ruthenium catalysts and gold catalysts with different supports were prepared by deposition precipitation method or volumetric immersion method, mainly characterized by XRD and TEM methods. Results showed that palladium catalysts and ruthenium catalysts were efficient for the hydrogenation of itaconic acid to high value-added chemicals, and Pd/C catalysts were conducive to the hydrogenation of itaconic acid to methyl-y-butyrolactone, and the activities of the catalysts were affected by the pretreatments of support. For investigate the effect of different catalysts supports on the hydrogenation of itaconic acid, Al2O3, TiO2, ZrO2 and CeO2 were selected as support to prepare palladium catalysts and ruthenium catalysts, and the selectivity of reaction products were affected by catalysts supports greatly. Au/ZrO2 was also prepared by deposition precipitation method and volumetric immersion method, and the former method was suitable for the preparation of Au catalysts.In order to prepare high-active Pd/C catalysts for the hydrogenation of itaconic acid to methyl-y-butyrolactone. the effect of active carbon pretreatment on the catalytic performance of Pd/C catalysts in the hydrogenation of itaconic acid was studied. The catalysts were prepared by deposition-precipitation and characterized by XRD, BET, NH3-TPD, TEM and FT-IR. Due to the modification of the surface functional groups, surface structure and surface acidities of active carbon via pretreatment, the Pd/C catalysts showed varied catalytic performances. High dispersion and uniform particles were conducive to the excellent activity of Pd/C catalyst with support copretreated with HNO3 and NaCIO, which exhibited 89.5% selectivity towards methyl-γ-butyrolactone at 180℃,4 MPa H2 for 20 h. The reaction conditions, including temperature, H2 pressure and reaction time, and the stability of catalysts were also studied in this paper.The hydrogenation of succinic acid and malic acid over different catalysts were also studied in this paper, but the experimental conditions and catalysts need to be further optimized. Generally, the hydrogenation reaction routes of biomass-derived acid was that the lactones were firstly formed, and then the lactones were further hydrogenated to polyols and ethers compounds. More researches on the hydrogenation of biomass-derived acid were needed.