Epoxidized Malaysian Elaeis guineensis palm kernel oil trimethylolpropane polyol ester as green renewable biolubricants

Green renewable biolubricants base stock based on polyol triester of epoxidized Malaysian Elaeis guineensis palm kernel oil and trimethylolpropane was produced and optimized by D-optimal design of response surface methodology. The in-situ generated performic acid catalyst was used to epoxidize the palm kernel oil polyol triester (PKO-TMPE). The epoxidation process was improved and the subsequent epoxidized palm kernel oil-polyol triester (EPKO-TMPE) was assessed for its lubrication possessions. The optimal condition for the epoxidation process was attained at the unsaturation, hydrogen peroxide and formic acid molar ratios of 1.00: 7.67: 5.00, temperature of 51.85 °C with 1.62 h reaction time, respectively. High epoxide yield of 92.5% and 100.0% relative conversion oxirane with low iodine value of 0.40 g/100 g I2 of EPKO-TMPE was produced at the optimal condition. The resultant epoxidized polyol ester displayed respectable lubrication properties with high flash point at 335 °C and oxidative stability temperature at 278 °C, decent viscosity index of 187 and pour point at −19 °C. Tribological assessments exhibited that EPKO-TMPE has revealed small coefficient friction of 0.16 at 40 °C and 0.18 at 100 °C in the hydrodynamic region and equivalent with some marketable lubricants. The rheological investigations showed EPKO-TMPE can be classified as ISO VG 46 lubricant grade with decent lubrication possessions of Newtonian fluids. This renewable green industrial biolubricant is likely to be applicable for turbine, compressor fluids and hydraulic oil applications.