Kinetics of Jojoba oil methanolysis using a waste from fish industry as catalyst

Abstract

Abstract In this study, the kinetics of the heterogeneous methanolysis of Jojoba oil using calcined shells of Mytilus Galloprovincialis as catalyst has been studied at different temperatures (45–55–65 °C), methanol:oil ratios (6:1–9:1–12:1) and catalyst percents (6–8–10%). The main products obtained are the jojobyl alcohols with pharmaceutical activity and Fatty Acid Methyl Ester (FAME) is produced as co-product. The catalyst was synthesized through calcination at 800 °C during 6 h. The catalyst was characterized by BET method, X-ray diffraction analysis (XRD), inductively coupled plasma atomic emission spectrometry (ICP) and transmission electron microscopy (TEM). The catalyst is mainly CaO which is macroporous, it has low porosity and turns to Ca(OH)2 in the course of the reaction. The reaction was performed immediately after the calcination process in order to avoid the poisoning of the catalyst by H2O and CO2. The poisoning of the catalyst and its effect has also been object of this study. In addition, external and internal mass transfer limitations and the effect of different calcination temperatures on the process have been studied. The proposed kinetic mechanism fits a sigmoidal curve because there are mass transfer limitations which control the process at the beginning of the reaction whereas the chemical reaction is the limiting step when a critical amount of FAME and jojobyl alcohols are formed. The chosen variables in this kinetic study have been the temperature, the initial catalyst percent and the methanol:oil ratio. The kinetic study describes the whole methanolysis process accurately.