Esterification and volatile compound manipulation using radiofrequency cold plasma

Esters are vital in many industries, including food; however, there are still significant opportunities to improve production efficiency, sustainability, and cost. Cold plasma was trialled as a novel tool to induce esterification. Cold plasma increased the esterification of hexanoic acid and methanol in gas and liquid phases. The use of argon significantly improved methanol-based esterification, when compared to air or nitrogen, of hexanoic acid in a mixed solution. This was attributed to interactions with the increased free hydroxyl radicals and hydrogen atoms produced by the argon-based plasma. However, air-based plasma significantly increased esterification when individually treating hexanoic acid in methanol, which indicates the potential use of different plasmas to induce esterification. Further evidence of this could be detected by analysing the intermediary compounds (from the proposed esterification pathway).