Production of sustainable two-stroke engine biolubricant ester base oil from palm fatty acid distillate

Abstract

In this study, palm fatty acid distillate (PFAD) was selected as the feedstock for biolubricant base oil production in two-stroke engine oils’ formulation. PFAD is a low-cost palm refinery by-product with a high free fatty acid (FFA) content (85%). The esterification of PFAD with neopentyl glycol (NPG) was conducted in the presence of a solid acid catalyst (SO42-/Fe2O3/Al2O3) to produce PFAD-NPG ester. Optimization profile indicated that PFAD conversion and PFAD-NPG ester yield were 84% and 82%, respectively, under optimum reaction conditions of 180 °C, 4 h, 2.0 wt% SO42-/Fe2O3/Al2O3 catalyst loading and a 2:1 PFAD to NPG molar ratio. The physicochemical properties of the base oil successfully comply with the Japanese Automotive Standards Organization (JASO) M345:2018 requirements for two-stroke oils in terms of sulfated ash content, kinematic viscosity at 100 °C and flash point. In addition, reusability of solid acid catalyst, SO42-/Fe2O3/Al2O3 was investigated, where PFAD conversion and PFAD-NPG ester yield were found to be excellent at 81% and 80%, respectively, which showed that the catalyst had good consistency after 5 cycles.