Glycerolysis of stearic acid using green catalyst

• Published in: Materials today : proceedings Vol. 87; pp. 303 - 310
• Main Authors: Aisha, Farra, Zahrina, Ida, Sunarno
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2023
• Subjects: Catalyst; Glycerolysis; Infrared; Natural deep eutectic solvents; Stearic acid; Glycerolysis; Stearic acid; Infrared; Natural deep eutectic solvents; Catalyst
• ISSN: 2214-7853; 2214-7853
• DOI: 10.1016/j.matpr.2023.03.286

Conventional fatty acid glyceride production by glycerolysis of fatty acids may be performed in the presence of homogenous acidic catalysts (H2SO4, HCl and H3PO4) or base catalysts such as KOH and NaOH. However, these catalysts have led to inefficient processes and environmental problems. Green catalysts, DES (deep eutectic solvents), are preferred in this process due to their low–toxicity, inexpensive raw materials, renewability, non–volatility, ease of separation, excellent reusability, and produce a relatively high conversion. In this work, a different type of DES from the less toxic compounds also known as NADES (natural deep eutectic solvents) were used to investigate their catalytic activities. Three types of NADES catalysts were synthesized by varied HBAs, including betaine hydrochloride and choline chloride, whilst the HBDs used in this study are citric acid, propionic acid, and sorbitol. Glycerolysis of stearic acid were conducted with the variation of molar ratios of reactants, temperatures, and catalyst concentrations in order to find the optimum condition as well as their effects on the absorption peaks of ester glycerol functional groups by infrared spectra. The studied reaction demonstrated that stearic acid conversions increase linearly with the increase in catalyst concentrations, molar ratios of the reactants and temperatures. At all temperatures and molar ratios of reactants, the infrared spectra revealed the identical peaks of ester glycerol functional groups were absorbed. This study found that the synthesized NADES catalysts provided suitable catalytic activities in the glycerolysis of stearic acid with relatively high conversions from 82.03% to 97.76%, indicating that NADES have great potential for a more environmentally safe process.