Catalytic Conversion of Epoxidized Palm Fatty Acids through Oxirane Ring Opening Combined with Esterification and the Properties of Palm Oil-Based Biolubricants

Abstract

In this work, biolubricants were produced by a two-step catalytic conversion of a palm-based fatty acid mixture. First, the epoxidation of fatty acids with H2O2 solution was performed at 45 °C for 4 h; it was catalyzed by performic acid generated in situ, and the reaction produced epoxidized fatty acids in >98% yield. Subsequently, the ester-based biolubricant product was obtained through a dual process of oxirane ring opening and esterification with 2-ethyl-1-hexanol in a temperature range of 70–130 °C and a reaction time of 2–6 h, with tetrafluoroboric acid used as a catalyst. The optimal synthesis temperature was 110 °C at a reaction time of at least 4 h, as these conditions resulted in 100% conversion. The highest yield of monoesters, one of the main products, was 70.5%. The catalytic performance remained consistent for 6 h, with a total ester-based biolubricant yield of 97.6%. The mono- and di-esters, the main components of the biolubricant, exhibited kinematic viscosities of 46.6 cSt (40 °C) and 7.6 cSt (100 °C), a viscosity index (VI) of 128, and a pour point (PP) of −43 °C. Ketone esters became the main components of the biolubricant products when high-temperature synthesis conditions were used. The viscosity and flow properties of ketone esters were strongly modified: they had an excellent VI of 159 and a PP of 3 °C. Biolubricants with these desirable and tunable properties can potentially be used as a base stock for wide temperature range utilization and as biodegradable-grade lubricants for industrial applications such as hydraulic fluids, turbine oils, and compressor oils.

A Review on the Effect of Metal Oxide Nanoparticles on Tribological Properties of Biolubricants

“…A high value of VI is desirable and kept in view while selecting the biolubricant. , Viscosity Index signifies the influence in viscosity with change in temperature. , The VI of tilapia oil was found to be 117 and compared with conventional mineral oil, and it was found that it has far better values than the latter one …”