Vegetable Oil to Biolubricants: Review on Advanced Porous Catalysts

Vegetable oil is one of the most potential sustainable feedstocks to produce fuels and chemicals. The review emphasizes isomerization of fatty acid as an important path for biolubricant production. The role of solid acid catalysts, including zeolites, was highlighted to design better isomerization catalysts. The isomerization is a favored mesoporous site with intermediate Brønsted acid strength, which is also enhanced after metal doping on a porous surface. The hierarchical ferrierite (FER) catalyst showed the best selective isomerization with the 10-membered ring cavities, which can be regenerated easily. FER can be produced using a low-cost organic structure-directing agent. The possibility to design two-dimensional pore zeolites with pore mouth selectivity was also discussed. Moreover, the challenges for biolubricant formulation, with focus on palm oil, were also discussed with a detailed comparison to other vegetable oils. The highest palm oil conversion was achieved over the base catalyst, namely, Sr-doped calcium oxide, with a low catalyst dosage. However, the biolubricant-based palm oil still needs many advancements to achieve industrial standards.