Catalytic performance of acidic ionic liquid-functionalized silica in biodiesel production

Acidic ionic liquid ([BsAIm][OTf]) was immobilized on sulfhydryl-group-modified SiO2 (MPS-SiO2) via free radical addition reaction. The [BsAIm][OTf] loading on acidic ionic liquid-functionalized silica ([BsAIm][OTf]/SiO2) was controlled through tuning the sulfydryl (SH) content of MPS-SiO2. All the samples were characterized by FT-IR, elemental analysis, N2 adsorption-desorption measurements and TG-DTA. The catalytic performance of [BsAIm][OTf]/SiO2 in the esterification of oleic acid and the transesterification of glycerol trioleate for biodiesel production was investigated. The results showed that with the increase of [BsAIm][OTf] loading on SiO2 the specific surface area and pore volume of [BsAIm][OTf]/SiO2 decreased, and the pore diameter of [BsAIm][OTf]/SiO2 narrowed. In the esterificaiton of oleic acid, the oleic acid conversion increased with the increasing [BsAIm][OTf] loading. In the transesterification of glycerol trioleate, with the increasing [BsAIm][OTf] loading the glycerol trioleate conversion decreased and the selectivities to glycerol monooleate and methyl oleate increased.

Graphical AbstractSiO2 supported ionic liquid catalysts with different ionic liquid loading were used in biodiesel production. Ionic liquid loading showed contrary influences on the catalytic activities in esterification of oleic acid and tranesterification of glycerol trioleate.Figure optionsDownload as PowerPoint slide