Kinetic study into levulinic acid production from rice husk in a biorefinery framework

Abstract

In the context of growing global demand for chemicals and renewable fuels, levulinic acid (LA) appears as a key platform chemical owing to its ability to be transformed into a wide range of industrial derivatives. This study investigates the chemical conversion of cellulose fraction of rice husk (RH) into LA, focusing on the influence of key reaction parameters and the kinetic behavior of the process within the framework of an integrated biorefinery system. The results of the experimental design indicate that temperature and solid loading are influential factors in the chemical conversion of cellulose fraction of RH to LA, finding an optimal reaction temperature of 167.27 °C and a solid load of 8% w/v. In parallel, it was found that a concentration of 5% v/v sulfuric acid maximizes the efficiency of the process, avoiding undesirable by-products. From a kinetic perspective, the reaction follows a pseudo-first-order model with a kinetic constant of k = 0.0309 min−1, a coefficient of adjustment R2 = 0.9892 and an activation energy for the reaction of 46.2 kJ mol−1. These findings contribute to the understanding of the LA production process, thereby enhancing the understanding of the underlying reaction mechanisms for potential future applications.