Kinetics and characterization of Gmelina arborea biolubricant via two-step transesterification

The increasing focus on environmental sustainability and the transition to renewable resources have driven interest in bio-based lubricants. Nonedible oils, such as those derived from Gmelina arborea seeds, present a viable alternative to conventional petroleum-based biolubricants. This study investigates the production and characterization of biolubricants from Gmelina arborea seed oil using a two-step process. Initially, the oil was transesterified with methanol to produce biodiesel, followed by esterification with trimethylolpropane (TMP) to obtain the final biolubricant. The optimized process yielded a maximum conversion of 91.7 % within 120 minutes, adhering to second-order kinetics with a rate constant of 0.001 wt/wt/min and an activation energy of 6.84 kJ/mol. Compositional analysis revealed a predominance of tri-esters (83.65 %) and esters (16.35 %). The oxidative stability of the resulting biolubricant meets the EN 14214 standards, while its viscosity characteristics align with ISO VG32 and VG46, with potential for VG68 after minor modification. • Kinetic study and characterization of biolubricant from Gmelina arborea seed oil. • Biolubricant production from Gmelina arborea seed oil via double transesterification. • A maximum biolubricant yield of 91.67 % was attained at reaction time of 120 min. • Second order kinetics best described the reaction rate with an Ea of 6.8423 kJ/mol. • The biolubricant consist of tri-esters (83.65 %) and esters (16.35 %).