Shea butter transesterification through clay-doped BaCl and ionic catalyst; process parameter impacts and kinetic evaluation

Abstract

In this work, Kinetic models were developed to evaluate shea butter (SB) transesterification with methanol using a novel developed clay impregnated with BaCl and ionic liquid (CD-BaCl-IL) catalyst to produce biodiesel and glycerol. To verify their suitability for the process, the synthesized catalyst was characterized using Scanning Electron Micrograph (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Fluorescence (XRF), and Braut Emmet Teller (BET). The biodiesel was characterized using GCMS (Gas Chromatography Mass Spectrometer) and FT-IR. Kinetic data using CD-BaCl-IL catalyst were obtained at 4 wt% catalyst, 2 hours reaction time, 300 rpm, 10:1 methanol/oil ratio, and 60 °C. Two elementary reaction mechanisms, Eley-Rideal (ER) and Langmuir-Hinshelwood-Hougen-Watson (LHHW) were employed to evaluate the kinetics. The kinetic analysis indicated that the LHHW model accurately represented the experimental data, exhibiting favorable parameters, an R² value of 0.999, and a variance of 2.61E-14 at 40°C. The rate-determining step (RDS) was the surface reaction that connected the adsorbed triglyceride and adsorbed alcohol. The rate rose as the temperature increased, suggesting an endothermic process. At a temperature less than the boiling point of alcohol, the frequency factor and activation energy for the reaction were 6.33E6h-1 and 45.3 kJ/mol, respectively. The feasibility of the CD-BaCl-IL catalyst was ascertained as the LHHW model determined that the RDS and the SB fuel properties complied with the ASTM D 6751 standards.