Synthesis of biodiesel from waste cooking oil catalyzed by β-cyclodextrin modified Mg-Al-La composite oxide

In this study, Mg-Al-La composite oxide loaded with ionic liquid [Bmim]OH was used as a catalyst for the synthesis of fatty acid isobutyl ester (FAIBE) via transesterification between waste cooking oil and isobutanol. Mg-Al-La composite oxide was synthesized from the β-cyclodextrin (β-CD) intercalation modification of Mg-Al-La layered double hydroxides. The structure of the catalyst was characterized via XRD, BET and EDS. The results showed that the interlayer space of the catalyst was increased due to β-CD intercalation modification. The IL/CD-Mg-Al-La catalyst exhibited significant catalytic activity and regeneration performance in transesterification due to large interlayer space and strongly alkaline ionic liquid. The yield of FAIBE achieved was 98.3% under the optimum reaction condition and 95.2% after regeneration for six times. The viscosity-temperature curve of FAIBE was determined and the phase transition temperature was -1 °C. The pour point of FAIBE was only -10 °C, which exhibited excellent low temperature fluidity.