Sustainable approach for catalytic epoxidation of oleic acid followed by in situ ring-opening hydrolysis with applied ion exchange resin

Abstract

Vegetable oils are rich in unsaturated bonds that can be converted to epoxidized oleic acid. They are considered sustainable, renewable, and also environmentally friendly. To date, there is a paucity of studies on production of dihydroxystearic acid (DHSA) using an eco-friendly ion exchange resin as it is not fully utilised. As a result, the aim of this study is to elucidate the mechanism of ring-opening by hydrolysis for the production of DHSA using amberlite IR-120H as a catalyst. The process of epoxidizing oleic acid involved the in situ generation of performic acid, which was then used to convert oleic acid into epoxidized oleic acid. This performic acid was created by combining formic acid, serving as the oxygen carrier, with hydrogen peroxide, acting as the oxygen donor. Under optimal conditions, the maximum relative conversion of oleic acid to oxirane was attained, with up to 85 %. Overall, DHSA with a high hydroxyl value (182 mg KOH/g), was successfully produced from oleic acid using in situ hydrolysis of epoxidized oleic acid.