Catalytic conversion of triglycerides by metal-based catalysts and subsequent modification of molecular structure by ZSM-5 and Raney Ni for the production of high-value biofuel

Abstract

We report herein a catalytic deoxygenation strategy that allows the direct removal of oxygen atoms from triglycerides by lowering the activation energy through the use of metal-based catalysts. Activation energies were investigated by TG analysis, employing fatty acid salts as model compounds. Introducing different metal atoms into carboxyl groups has a substantial effect on the dynamic pyrolytic behavior, and decomposition activation energies varied in the range 80–260 kJ/mol. The catalytic cracking of soybean oil using SnO as a representative catalyst has been investigated in a 5 L reactor, whereby the catalyst lowered the decomposition temperature by approximately 40 °C and gave a conversion rate of approximately 66 wt%. A catalytic conversion mechanism has been proposed based on the results of TG-FTIR, GC, and GC-MS analyses. The pyrolysis products from the deoxygenation process had a high alkene content, endowing them with great potential for conversion into cyclic hydrocarbons used in real aviation fuels. Such conversion through aromatization and hydrogenation over ZSM-5 and Raney Ni catalyst has been investigated. Overall, a new refining process, including conversion of triglycerides to alkanes and terminal alkenes catalyzed by metal compounds, furnishing viable aviation and diesel fuels, is reported.