Synthesis of Alkyl Levulinates from α-Angelica Lactone Using Methanesulfonic Acid as a Catalyst: A Sustainable and Solvent-Free Route

In the present study, a green and readily effective route is presented, using for the first time, methanesulfonic acid (MSA) as a catalyst to produce alkyl levulinates (ALs) via the addition of alcohols to alpha-angelica lactone (alpha-AL). A smooth procedure was developed that resulted in the production of high-purity ALs, with complete conversions and high yields (99.1-99.8%), within 20 to 60 min of reaction in the presence of 0.5 mol% MSA. The reactions were carried out solvent-free, at room temperature, and in atmospheric air. Reaction conditions were optimized, and equimolar amounts of alcohol reagent were used. This work presents the main advantages of the use of a catalyst (MSA) that is low cost, easily biodegradable, and does not release toxic gases into the environment, but has an acidic strength comparable to that of other mineral acids. Therefore, this study proves the remarkable efficiency of MSA as a catalyst in the synthesis of ALs through an economically and environmentally favorable route.