| 초록 |
Glycerol is formed as a byproduct during the manufacture of biodiesel by transesterification of oils with alcohol. With the increased expansion of biodiesel and the sharp decrease of glycerol prices, glycerol is expected to become a major platform chemical. Glycerol carbonate, which can be synthesized from glycerol, is a new and interesting material in the chemical industry. In the present work, UiO-66 was prepared and their catalytic performance in the synthesis of glycerol carbonate (GC) was investigated. Zirconium-based MOF catalyst UiO-66-X (X =H, NH2, Br, OH), were synthesized through the solvothermal method and direct mixing method. The catalysts have been characterized by XRD, FT-IR, SEM, BET, TPD, Knoevenagel condensation and acetalization and TGA. The catalytic conversion of glycerol was carried out in a semi-batch reactor system, under vacuum or purging nitrogen for removing ammonia. The UiO-66 series were proved to be effective heterogeneous catalysts for the synthesis of GC from glycerolysis of urea. UiO-66-OH catalyst showed the highest activity because -OH group of UiO-66-OH having high hydrophilic character assisted the adsorption of the hydrophilic glycerol to the active center. High temperature and long reaction time, and high degree of vacuum were favorable for the high conversion of glycerol. |
