A kinetic study of the gas-phase esterification of free fatty acids in rubber seed oil

摘要

Using rubber seed oil with high acid value as material, the kinetics and technological conditions of gas-phase esterification of free fatty acids (FFA) with methanol was studied. Under the condition of a flow rate of gaseous methanol of 2.5L/min, the variables affecting the conversion rate during the gas-phase esterification, such as catalyst mount and reaction temperature, were investigated. The experimental results show that the final acid value of rubber seed oil is lower than1.0 mg KOH/g oil within 30 min by the following optimal condition: a flow rate of gaseous methanol of 2.5L/min and a catalyst amount of 3% relative to oil and a temperature of 105°C. Under these conditions, the gas-phase esterification follows second order kinetic equation. The reaction velocity accelerates with increasing temperature and the relationship follows Arrhenius equation while the activation energy of reaction is 121.409 kJ.mol-1.