Synthesis of Novel Biolubricants from Waste Cooking Oil and Cyclic Oxygenates through an Integrated Catalytic Process

The present research and development for lubricant production from vegetable oils rely on traditional (trans)esterification, etherification, and/or chemical modifications of triglycerides and free fatty acids (FFAs). However, the final products suffer from at least one of the following: poor low-temperature characteristics, low oxidation stability, low viscosity index, or poor solubility of additives. This study presents a novel approach to produce biolubricants (BL) from the reaction of waste cooking oil (WCO) and cyclic oxygenated hydrocarbons (COHCs) (cyclopentanone, cyclopentanol, anisole, and 2-methylfuran) via a four-step pathway: hydrolysis, dehydration/ketonization, Friedel-Crafts (FC) acylation/alkylation, and hydrotreatment. Such reactions were successfully demonstrated using model compounds (oleic acid and stearic acid) and actual WCO feedstock. The process resulted in the production of novel BLs that were consisted of molecules with several mutual properties: (1) long and linear hydrocarbon chains, (2) low to zero unsaturation, (3) minimal branching, (4) naphthenic rings and cyclic structures, and (5) polar molecules. We showed that such BLs can be synthesized with pour-point, kinematic viscosity (at 40 degrees C), viscosity index, and Noack volatility of -12 degrees C, 47.5 cP, 186, and 17 wt %, respectively.

Automated summary

This study proposes a novel approach to produce biolubricants through the reaction between waste cooking oil and cyclic oxygenated hydrocarbons. The resulting biolubricants have long hydrocarbon chains, low unsaturation, naphthenic rings, and polar molecules, demonstrating good pour-point, viscosity, viscosity index, and volatility properties.