Kinetics of free fatty acids esterification in waste frying oil using novel carbon-based acid heterogeneous catalyst derived from Amazonian Açaí seeds – Role of experimental conditions on a simpler pseudo first-order reaction mechanism

Abstract

This study reports the kinetics of free fatty acids esterification in waste frying oil, based on a simpler non-conventional pseudo first-order homogeneous reaction mechanism using a highly-efficient acid heterogeneous catalyst derived from seeds of Açaí (Euterpe oleracea Mart.), subjected to changes in temperature, catalyst dosage, MeOH:Oil ratio, and stirring speed. Statistical analyses revealed significant effects all four conditions (p < .05) on the reaction's apparent rate constant (k1) over their different pre-defined levels. Reaction mechanism was inferred to be fundamentally acid ionic exchanges with the oil/water film on catalyst's surface, neglecting kinetically controlled liquid-to-liquid splitting and autocatalyzed esterification.