Heterogeneously catalyzed etherification of glycerol to diglycerol over calcium–lanthanum oxide supported on MCM-41: A heterogeneous basic catalyst

•Solventless etherification of glycerol to diglycerol.•Heterogeneous basic catalyst based on calcium–lanthanum oxide supported on MCM-41.•Ca1.6La0.6/MCM-41 showed glycerol conversion of 91% and diglycerol yield of 43%.•Correlation between catalyst activity and leaching of metal oxides during the reaction.•Production of αβ isomer as the favored diglycerol product during the reaction.

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%Ca1.6La0.6/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.

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