Shape selectivity effects in etherification of glycerol to diglycerol isomers in a solvent-free reaction system by Li-Mg/SBA-15 catalyst
Performance and shape selective effect in the etherification reaction of glycerol to diglycerol by Li-Mg/ SBA-15 catalyst was investigated. The reaction was carried out at 240 °C with 2 wt% of catalyst for up to 18 h. The catalyst characteristics were elucidated through surface, SEM and TEM analyses. 10Li10Mg/SBA-15 catalyst showed the highest glycerol conversion and diglycerol selectivity of 77 and 82 %, respectively with corresponding diglycerol yield of 63 %. The distribution of diglycerol isomers was successfully elucidated. αβ-diglycerol isomer was predominantly formed in contrast to aa isomer in homogeneously catalyzed reaction. Springer Science+Business Media New York 2013.
Heterogeneously catalyzed etherification of glycerol to diglycerol over calcium-lanthanum oxide supported on MCM-41: A heterogeneous basic catalyst
The catalytic etherification of glycerol using calcium-lanthanum oxide supported on MCM-41 as a stable heterogeneous basic catalyst was investigated. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were when characterized using different techniques. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca1.6La 0.6/MCM-41 catalyst resulted in the highest glycerol conversion of 91% at the diglycerol yield of 43%. The distribution of diglycerol isomer in the etherification of glycerol was studied, and the value of the sum of two dimers (ββ′ + αβ = 67%) was found to be higher than that of αα′ dimer (33%) after 8 h of reaction. Thus, the major reaction occurred inside the porous area instead of the external surface area.
Gholami, Zahra,Abdullah, Ahmad Zuhairi,Lee, Keat Teong