Mesoporous BaCO ₃ / C And SrCO ₃ / Preparation And Catalytic Glycerides C Composites Exchange Properties

The transesterification is one of the most important ways to synthesis glycerol carbonate from glycerol. There are many kinds of catalysts used to catalyze the transesterification; the solid base catalyst with highly active, environment-friendly can effectively promote the transesterification of glycerol with dimethyl carbonate. The composite catalysts with special structure, which show distinct advantages in the transesterification, have been taken priority of selection. Ordered mesoporous carbon materials possesses more remarkable properties, such as ordered pore structure, narrow pore distribution, high specific surface area and high thermal stability, which are considered to have great potential application as catalysts or supported materials.In this thesis, we have successfully synthesized ordered mesoporous BaCO3/carbon and SrCO3/carbon composite materials for the first time via evaporation induced tri-component co-assembly method followed by carbonization by using phenolic resol as a carbon source, inorganic salts of barium nitrate and strontium nitrate as precursors and amphiphilic triblock copolymer pluronic F127as a template. The mesoporous BaCO3/carbon and SrCO3/carbon composites with different contents of BaCO3(9.1%-44.7%) and SrCO3(8.9%-45.7%) were obtained by adjusting the ratio of inorganic precursor to organic precursor. The structure of the BaCO3/carbon and SrCO3/carbon composites was characterized by XRD, TEM, BET, TG etc. The results show that the materials possess large specific surface area, highly ordered pores, and narrow pore size distribution.The mesoporous BaCO3/carbon and SrCO3/carbon composites materials exhibited high catalytic activity in the synthesis of glycerol carbonate formation by the transesterification of glycerol with dimethyl carbonate under the conditions the molar ratio of dimethyl carbonate (0.9007g) to glycerol (0.1846g) about5, catalyst0.1g, DMF5.426g,140℃,2h. When BaCO3content in the BaCO3/carbon composites was18.5%and SrCO3content in the SrCO3/carbon composites was16.3%, high conversion of glycerol (97.9%,98.8%) and selectivity to glycerol carbonate (>98%) were obtained.The ordered mesoporous BaCO3/C-2and SrCO3/C-2could be reused five recycles with gradual loss in activity, which was caused by the formation of carbon deposition on the catalyst surface together with the electronic modification of Ba(II) and Sr(II).