(57d) Green Modification and Synthesis of Low Pour Point Vegetable-Based Lubricants in Solvent-Free System

Due to poor biodegradability and toxicity of mineral-based lubricants, which cause serious environmental pollution, the development and application of plant-based biolubricants are increasing. Unluckily, low stability and terrible low temperature performance restrict vegetable oils to use as lubricants directly. Hence, the paper tried to find an efficient and green way to modify the vegetable oil derivative-oleic and obtained high-performance biolubricants. Synthetic steps included esterification and epoxidation of oleic acid catalyzed by lipase, ring opening reaction and subsequent hydroxyl esterification catalyzed by ionic liquids. Meanwhile, catalytic effects of ionic liquids were compared with popular chemical catalysts. Sulfuric acid was the most efficient ring-opening catalyst, then the best esterification effect of ring-opening hydroxyl was 1-hexyl-3-methylimidazole hexafluorophosphate (an alkyl imidazole acid ionic liquid) that had relatively high ring-opening effect. Modified biolubricants exhibited excellent viscosity index (>116) and low temperature performance (pour point<-48℃). High frequency reciprocating friction experiment results showed that their lubrication performance was particularly outstanding. The result provides a new method for improving vegetable oils as biolubricants greenly and efficiency.