Synthesis and Evaluation of Jatropha Oil Branched Esters as Potential Fire Resistant Hydraulic Fluids

Abstract

Jatropha oil (Jatropha curcas L.), a non-edible oil with oleic acid (45.7%) and linoleic acid (33%) as major components, was used to prepare basestocks for biolubricants. The hydrolyzed fatty acids underwent reaction with two iso-alcohols, 2-ethyl-1-hexanol (EH) and 3,5,5-trimethyl-1-hexanol (TMH) and 5 different polyols, namely neopentyl glycol (NPG), 2-methyl-2-propyl-1,3-propandiol (MPPD), trimethylolpropane (TMP), trimethylolethane (TME) and pentaerythritol (PE) at around 140 ºC in presence of catalyst p-toluenesulfonic acid (p-TSA) and xylene as solvent. The yields for the branched mono- and polyol esters ranged from 90% to 97.5%. The physico-chemical, lubricant and tribological properties of these esters as well as their 1H NMR, 13C NMR, IR and ESI-MS techniques were investigated. Among the products, polyol esters were found to possess good viscosity indices, good foam stability, higher thermal stability and higher flash and auto ignition points compared to branched mono esters. TMP and TME esters have matched the specifications of ISO VG 46 and PE esters match ISO VG 68 fire resistant hydraulic fluids, which are in high demand.