Enzyme-catalyzed preparation of polyol ester lubricants and performance research-based on pelargonic acid, oleic acid and trimethylolpropane

Abstract

Chemical oil esters synthesized by polyols and fatty acids are biodegradable and have ideal physicochemical and lubricating properties as compared to mineral lubricants. Using sulfuric acid and lipases as catalysts, a polyester lubricant was synthesized from pelargonic acid (PA) and trimethylolpropane (TMP). Lipase-catalyzed goods are superior and more in accordance with green production requirements. The optimized reaction conditions of lipase catalytic were 50 °C, 15%wt enzyme content, PA: TMP= 3.3:1 %, and 15 % water content. When the time reached 96 h, the accumulation of trimethylolpropane (TMPTP) reached 82% under these conditions. The TMPTP purified by molecular distillation has a flashpoint of 276 °C, a pour point of − 57 °C, and a viscosity index of 145, making it more suitable for extreme environments. On this basis, to improve the viscosity-temperature performance of the substrate, a certain proportion of oleic acid (OA) is added. Low viscosity (kinematic viscosity of 4.86–9.54 mm2/s at 100 °C), high viscosity index (VI > 160), low pour point (−50 °C), and low friction coefficient (COF) of 0.09 ∼ 0.11 is among the properties of a series of synthetic hetero-chain mixed esters, which can meet the needs of a variety of extremely low temperatures and complex working conditions.