SO3H Functionalized Mesoporous Carbon as a Potential Catalyst to Obtain Glycerol Oleate Esters from Crude Glycerol

Abstract

AbstractGlycerol reactions, such as esterification, combined with its purification process, have been largely studied in recent years. Catalytic esterification of glycerol with oleic acid (OA) can generate different products of high commercial value such as glycerol mono-, di- and tri-oleate with a range of food, pharmaceutical, cosmetic, and industrial applications. The objective of this study was to purify the crude glycerol from the biodiesel industry, using activated carbon followed by ion-exchange resins, and use it in the esterification of oleic acid over –SO3H functionalized carbon mesoestructured from Kaist (CMK). In the first purification step, using activated carbon, a maximum glycerol content of 89.9% ± 0.06 was obtained. In a second step, using ion-exchange resins, the maximum glycerol content increased to 98.2% ± 0.05. The glycerol esterification with oleic acid and CMK3-SO3H as catalysts were carried out using a glycerol and oleic acid molar ratio 1:3, in a closed reactor at 120 °C and 5% (w/w) of catalyst (related to the amount of fatty acid), under agitation and inert atmosphere for 5 h. For these reactions, the highest conversion achieved was 84.39% ± 0.38 with a selectivity of 78% ± 0.22 (mono-, di- and tri-oleate). These results showed that the acid treatment on mesoporous carbons could be useful to obtain catalysts for the esterification of fatty acids, with the advantage of their possible reuse.KeywordsCMKEsterificationEstersGlycerolOleic acid