Enzymatic Synthesis of a Polyol Ester from Levulinic Acid and Trimethylolpropane and Its Tribological Behavior as Potential Biolubricant Basestock

Abstract

In this study, a polyol ester from levulinic acid (LA) and trimethylolpropane (TMP) was synthesized by enzymatic catalysis in a solvent-free system. The total conversion of TMP reached up to 84% on average after lipase recycling for five times. The produced ester showed excellent lubrication properties, such as high viscosities at 40 °C (86.53 mm2/s) and 100 °C (8.91 mm2/s), a good viscosity index (49), a low pour point (−27 °C), and a high flash point (223 °C). The frictional wear behavior was evaluated on a four-ball test machine (FTM) by adding the ester into a reference mineral oil. The blend with 10% ester showed a smaller wear scar diameter (WSD) (0.62 mm) when compared with that of pure mineral oil (0.78 mm). The results demonstrated that the obtained ester has huge potential as biolubricant basestock.

Sustainable Biocatalytic Synthesis of a Second-Generation Biolubricant

“…This outcome aligns with findings from other investigations that utilized lipase quantities equivalent to or below 2.5% (w/w) [31,38,42,48,50,54] or moderately exceeding this amount [33,44,46,47,51].…”

“…This outcome aligns with findings from other investigations that utilized lipase quantities equivalent to or below 2.5% (w/w) [31,38,42,48,50,54] or moderately exceeding this amount [33,44,46,47,51]. Derived from the obtained results, the optimal concentration of lipase is 2.5% (w/w), as any higher amounts do not enhance the process in terms of conversion or time but rather increase the cost associated with the biocatalyst.…”

Prospects of Plant-Based Trimethylolpropane Esters in the Biolubricant Formulation for Various Applications: A Review

“…Full synthetic gear oil has excellent physicochemical properties, including a high viscosity index, kinematic viscosity at 100 °C, and the lowest pour point, −43 °C. Tribology of food grade lubricants can be improved by the modification of fatty acid structure, such as with the use of levulinic acid (LA). LA is feasibly produced from glucose, fructose, starch, and lignocelluloses residues and is widely used in a variety of applications, including food flavoring, composites, and fuel (Zhu et al, 2020). The esterification between TMP and LA produced a trimethylolpropane trilevulinic (TMP-tri-LA) ester with viscosity index, flash point, and pour point being 49, 223 °C, and −27 °C, respectively.…”

Enzymatic synthesis of a novel solid–liquid phase change energy storage material based on levulinic acid and 1,4-butanediol

“…LBE is usually produced by enzymatic or chemical esterification of levulinic acid with polyol (Trombettoni et al 2017 ; Zhu et al 2020 ). Compared with the chemical method, enzymatic catalysis has many advantages, such as environmental friendliness, less by-products, and mild operation conditions (Mukherjee et al 2015 ; Jaiswal and Rathod 2021 ).…”

“…Using hexane as solvent and Novozym 435 as a catalyst, citronellyl palmitate ester was obtained through an esterification reaction with a yield of more than 95% (Ortiz et al 2019 ). Enzymatic reactions with organic solvent systems require expensive reactors and tools (Liu et al 2021 ), thus limiting the application in the industry (Zhu et al 2020 ). The solvent-free system has the advantages of high selectivity and a simple purification procedure.…”