Catalytic deoxygenation of C18 fatty acids over HAlMCM-41 molecular sieve

Abstract

The large demand for energy combined with ecological, economic, and social reasons encouraged the studies for alternative sources of fuel. The deoxygenation process of oils and fatty acids has emerged as a promising resource in obtaining fuels. This paper studied the deoxygenation process of oleic and stearic acids carried out in a distillation system, under the temperature of 450 °C over MCM-41, AlMCM-41-41, and HAlMCM-41 molecular sieves, which were synthesized by direct hydrothermal synthesis method and characterized by X-ray diffraction (XRD) spectroscopy in the infrared site (FTIR), adsorption and desorption of N2, and scanning electron microscopy (SEM). The products were analyzed by gas chromatography (GC) and acid-base titration. The results showed that stearic acid deoxygenates more than the oleic acid, and that the performance of HAlMCM-41 was superior to AlMCM-41, indicating that the total acidity positively influenced the process. Furthermore, from the stearic acid deoxygenation, it obtained mainly heptadecanes (C17:0) structures, while the oleic acid produces heptadecenes (C17:1).