The industrial production of renewable lubricant glycerol trioleate was simulated using a microwave reactor through esterification of glycerol with oleic acid in the presence of methane sulfonic acid catalyst under solvent-free conditions. The interaction effects of operating temperature, catalyst concentration, and reaction time were investigated. A conversion of 90% was achieved in optimal conditions (191 degrees C, 0.3 wt% and 104 min reaction time) and reduced pressure environment. This result was impressive, compared to the conversion abounded with conventional reactor (39.5%). Furthermore, two different industrial grade crude glycerols were used as starting materials to evaluate the effect of impurities. The findings confirmed that the presence of impurities reduced both selectivity and total conversion significantly. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.