Esterification of Solketal with Recovered m-Chlorobenzoic Acid: Concomitant Formation of Glycerol Esters under Acid Catalysis

The valorization of glycerol has motivated the development of synthetic routes for obtaining value-added derivatives¹. In this work, the esterification of solketal with m-chlorobenzoic acid (m-CBA) recovered from previous epoxidation reactions was investigated as a strategy aligned with green chemistry. The reactions with solketal were conducted under p-TSA catalysis and monitored by GC-MS. As described in the literature², the exclusive formation of solketal esters was expected. Although the chromatographic profile initially indicated these products, direct insertion ESI-MS and NMR analyses also revealed the formation of mono- and di esterified aromatic glycerol esters derived from m-CBA. Control experiments using glycerol as the substrate, monitored by ESI-MS, did not indicate the formation of these products under the same reaction conditions. It is suggested that, under acidic conditions, acetal ring opening of solketal occurs, generating glycerol in situ, followed by esterification, indicating a possible alternative route for obtaining aromatic glycerol esters.