Abstract
In this work, we tackle two linked investigations targeted at developing sustainable chemical processes. These processes are (i) the synthesis of biodiesel from palm oil utilizing inorganic perovskite-based catalysts and (ii) the esterification of levulinic acid with isopropanol to a fuel additive while studying the thermodynamics of the surface-driven heterogeneous catalytic reaction. Both research points focus on the global demand for renewable energy sources and effective catalytic systems to power eco-friendly chemical operations.
For the first investigation, the esterification of levulinic acid with isopropanol was utilized as a model process to produce esters with potential uses as green fuel additives. The Eyring equation was used for calculating the thermodynamic parameters such as Gibbs energy of activation, Δ𝐺‡, enthalpy and entropy of the reaction, Δ𝐻‡ and Δ𝑆‡, respectively, for better thermodynamic comprehension of the reaction process. The supported perovskite catalysts were efficient in the conversion of LA, with the reaction preferring an ester product. However, difficulties such as the lengthy synthesis methods for the catalysts and the necessity for precise reaction tuning were observed. The non-linearity of temperature variation studies led to a postulation that the conversion of LA to an ester over the perovskite catalytic systems can be analyzed using the super- and sub-Arrhenius kinetics depending on the nature of the catalyst used.
The second project investigated the production of biodiesel from palm oil in a transesterification process with methanol, ethanol, and isopropanol as alcohols. Lanthanum and cerium-based perovskites were synthesized and characterized in a systematic manner using techniques such as scanning and transmission electron microscopy (SEM and TEM) and the powder X-ray diffraction (PXRD). The catalytic performance of these perovskites was tested at various temperatures, exhibiting differing percentages of biodiesel production between 323.15 K and 348.15 K that were attributable to both the kinetics phenomena and surface structure of the catalysts used. The best yields were found at intermediate temperatures which is indicative of an ideal balance of the reaction kinetics and catalyst stability.
The outcomes of this work shine light on the relevance of catalyst designing and processing optimization in accomplishing sustainable chemical transformations. The findings are an addition to the increasing body of knowledge on renewable energy and green chemistry, having implications for both academic research and industry applications.