Effect of Temperature on Interesterification of Rapeseed Oil with Methyl Acetate in Presence of BuOK/BuOH

Abstract

If the interesterification reaction of rapeseed oil with methyl acetate at reactant to oil molar ratio of 18:1 in presence of potassium tert-butoxide in tert-butanol of molar ratio to oil 0.08 is conducted at a temperature of about 35 °C, reaction time for full conversion of oil is shorter than one hour, while at a temperature of 55 °C it is approximately 15 minutes. Reaction time at the desired temperature has a wide "optimal" range and cannot be an effective variable for the process optimisation. Experimental results at the temperature of 25 °C confirm the pseudo-first order of the reaction, which lowered towards the end of the reaction. The pseudo-first order rate constant was 0.63 min-1. Fuel characteristics of the interesterification reaction mixtures without purification improved with the rising of reaction temperature from 35 °C to 55 °C, however, they fail to meet the requirements of standard EN14214 for biodiesel. Methyl acetate to oil molar ratio 18:1 is too low for obtaining products with kinematic viscosity below 5.0 mm2/s.