Continuous Flow Hydrolysis of Sunflower Oil Using Sub-critical Water

The use of sub-critical water has recently been proven to be a successful medium for conducting hydrolysis reactions without employing acid or alkali catalysts. This work presents the usage of sub-critical water as both solvent and reactant for the continuous flow hydrolysis of sunflower oil (triglyceride) in a tubular reactor. The hydrolysis products of sunflower oil are fatty acids and glycerol. Fatty acids are an important intermediate product for many industrial applications. Experiments were undertaken between pressures of 100 to 200 bar and temperatures of 270 to 350 oC. The water to oil ratio was 50:50 v/v. Fatty acid was found to act as an acid catalyst that allowed a simple process and high yield. The rate of the hydrolysis was enhanced by increasing temperature and residence time. The highest yield up to 90% was obtained at the conditions of 8 minutes reaction time, 50:50 v/v water oil ratio, 200 bar and 350 oC. The results show promise for integration of a continuous flow hydrolysis and an esterification process into a one step continuous procedure for biodiesel production.