Kinetic models of candle shell alkaline hydrolysis in obtaining oxalic acid

Abstract

The kinetic reaction of alkaline hydrolysis of candlenut shells to produce oxalic acid was investigated. It was performed for the non-catalyzed solid-liquid heterogeneous reaction in a range time of 30 to 90 minutes and temperature of 60^oC to 90^oC. This study showed that the reaction fitted the pseudo-first-order model, confirmed from the determinant coefficient value of 0.9182 to 0.9751, and the kinetic constant, evaluated using Arrhenius' law, was k= 0.034751 e^(-140.23⁄T). The rate control mechanism based on the shrinking core model was diffusion control, validated from determinant coefficient near one, from 0.9246 to 0.9766.