Production of a Biofuel that Keeps the Glycerin as Monoglycerides by Using Supported KF as Heterogeneous Catalyst

Abstract

This study describes the results obtained in the synthesis of a biofuel that avoids the glycerol production by applying supported KF as alkaline heterogeneous catalyst, to generate two moles of fatty acid methyl esters and one mole of monoglyceride, from one mol of triglyceride. In this respect, the selective transesterification process of sunflower oil with methanol was carried out with KF10 wt % supported on three different solids, Al 2 O 3 , ZnO and MgO. The standard experimental conditions employed in the heterogeneous selective methanolysis reaction were: 12 mL of sunflower oil, 2.7 mL of methanol, 0.8 g of catalyst, at 65 °C temperature and one hour of reaction time. In all cases were obtained 100% conversion, with high selectivity values, greater than 90%, and quite suitable viscosity values, 4.5-8.5 cSt. In this way, the best catalytic behavior in the first use was obtained by using Al 2 O 3 as support. However, although in the five consecutive reuses all exhibited a continuous decrease in the catalytic activities; the lower one was for KF catalyst using MgO as support. In summary, these three KF supported catalysts have OPEN ACCESSEnergies 2013, 6 2 resulted to be very suitable to obtain a new biofuel, similar to conventional biodiesel, applicable to diesel engines.