Non-catalytic esterification of palm fatty acid distillate with 2-ethyl hexanol for high purity production of biolubricant ester

Palm fatty acid distillate (PFAD), a byproduct of crude palm oil (CPO) refining, is an attractive feedstock for biolubricants due to its inedible nature and the fact that its cost is lower than that of palm oil. Ethylhexyl ester is a novel high-performance biolubricant synthesized via the non-catalytic esterification of PFAD with 2-ethylhexanol (2EH), normally the esterification of PFAD with methanol (MeOH). By substituting a longer carbon chain alcohol for MeOH, the cold flow characteristics, flashpoint, and oxidative stability are improved. The optimal esterification parameters were 1:2 (PFAD:2EH) mole ratio, 180 degrees C, 100 rpm, and 6 h. The kinetic reaction fitted the pseudo-first order well with an activation energy of 29.89 kJmol(-1) and a pre-exponential factor of 15.05 min(-1). The increase in ester purity and conversion from 44 to 95% and 97 to 99.5% were achieved by fractionation via vacuum distillation at 125-200 degrees C and 47-55 mbar. The physicochemical properties of the ester appear to be suitable as ISO VG 10 lubricant for hydraulic application in terms of kinematic viscosity at 100 degrees C of 2.9 mm(2)/s(-1), a viscosity index of 243, and a flash point of 180 degrees C. This study will assist in designing industrial biolubricant reactors. (c) 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.