One-pot synthesis of canola oil based biolubricants catalyzed by MoO3/Al2O3 and process optimization study

摘要

Research on the formulations of vegetable oils into biolubricants has gained significant interest due to their promising lubricity and eco-friendly properties. The epoxidation of unsaturated groups in vegetable oil followed by epoxide ring opening by acetic anhydride provides vicinal di-O-acetylated glyceryl fatty acid esters as a stable and potential biolubricant. The present study is emphasized on the development of a single and novel heterogeneous catalyst for both the reaction steps (epoxidation and di-O-acetylation) to produce biolubricants from canola oil and canola biodiesel (methyl fatty acid esters). Group VI metal oxides (Cr, W and Mo) impregnated on aluminium oxide were prepared and screened for their catalytic activity on the epoxidation and vicinal di-O-acetylation steps. MoO3/Al2O3 was found to be the most effective catalyst for the epoxidation of canola oil and canola biodiesel, and its further conversion to corresponding vicinal di-O-acetylated derivatives (biolubricants). The response surface methodology (RSM) was employed for optimizing the process conditions and statistical analysis for both the reaction steps separately. Based on the process optimization study, 10 wt% MoO3/Al2O3 was found to be the best catalyst for 100% conversion of unsaturated groups to the epoxide and its further conversion to vicinal di-O-acetylated products in one-pot synthesis. All the products were confirmed by H-1 NMR and mass spectrometry. The physico-chemical characterization of MoO3/Al2O3 was carried out to evaluate and understand the properties required for effective catalysis. This study discloses MoO3/Al2O3 as a promising catalyst for the synthesis of biolubricants from vegetable oils. (C) 2016 Elsevier B.V. All rights reserved.