5-27: Synthesis of biodiesel from fatty acids of palm oil using modified chitosan as a heterogeneous catalyst

Biodiesel has become more attractive recently because of its environmental benefits and the fact that it is made from renewable resources. The cost of biodiesel, however, is the main hurdle to commercialization of the product. Therefore, more research is developed for the optimization of production of biofuels. Two major problems are found for the biodiesel production by the transesterification reaction (conventional process), the use of raw materials of high acidity, restricting the method to use a small range of vegetable oils and the use of homogeneous catalysts. This paper presents as an alternative route for biodiesel production process of esterification of fatty acids in the presence of heterogeneous catalysts based on modified chitosan. One of the main advantages of using this route is that the product, biodiesel, glycerin is free. The catalysts were prepared prepared by the method of acidification of chitosan with sulfuric acid solution (0.1, 0.5 and 1.0 mol/L H₂SO₄). The reaction mechanism was proposed and the separate effects of the alcohol (methanol and ethanol); molar ratio of alcohol/fatty acid (3:1, 6:1 and 12:1) and mass ratio of catalyst (2.5, 5.0 and 10.0% m/m) were investigated or 120 min. The biodiesel conversion reached a yield of 80 and 90% with methanol and ethanol, respectively. The catalyst was recovered and reused seven times, maintaining a catalytic efficiency of about 80%. The properties of samples of biodiesel produced by heterogeneous catalysis was evaluated and are in accordance with the recommended fuel properties.