Ultrasound assisted interesterification of babassu oil with acetates using acid catalysts for biodiesel and triacetin production

The ultrasound-assisted (US) interesterification of babassu oil with methyl, ethyl and butyl acetates was carried out via acid catalysis for biodiesel production with triacetin as an additive and therefore filling the gap in the field of US induced interesterification reactions. The scanning for the best catalyst was performed using sulfuric, methanesulfonic, p-toluenesulfonic, phosphoric and acetic acids. In order to achieve optimal conditions reactions varied in terms of reactant molar ratio, type and concentration of catalyst, temperature (20 to 50 °C) and ultrasonic energy (120 to 320 W). Using ethyl acetate, reactions were carried out at various molar ratios of oil to acetate (1:12 to 1:72) using sulfuric acid (0.5 % w/w_T). The 1:60 experiments were carried out with sulfuric acid concentrations ranging from 0.5 % to 3 % (w/w_T). The best catalytic activity was sought using the acids at a concentration of 2.5 %, with 200 W and 1:60. The best catalytic activities were achieved with H₂SO₄ followed by CH₃SO₃H and CH₃C₆H₄SO₃H and the reactivity follows the ethyl→methyl→butyl trend. The best results were achieved using ethyl acetate with H₂SO₄ yielding 95.4 % biodiesel plus triacetin with a content of 17.6 % of triacetin in 180 min, which represents an intensification of 25.4 % compared to conventional heating.