Sustainable Synthesis of Massoia Lactone from Liamocin Polyol Lipids Produced by <i>Aureobasidium pullulans</i>

Massoia lactone (ML) is a valuable chemical with a variety of uses that can be sourced from extracellular polyol lipids, called liamocins, produced by Aureobasidium pullulans. In this study, sustainability and safety considerations were used to guide the development of a new method for converting liamocins to ML that would be easily scalable and could be performed in a continuous flow reactor. Methyl ethyl ketone (MEK) and water are used as cosolvents, and biobased carboxylic acids (e.g., citric acid) are used as Brønsted acids to catalyze sequential hydrolysis and dehydration reactions. The acids exhibited salting-in effects on MEK–water mixtures, allowing for reactions to be performed in a single liquid phase. In batch reactors at 70 °C and atmospheric pressure, long reaction times (∼200 h) are required for the dehydration reaction to reach equilibrium and achieve yields approaching the apparent theoretical limit (∼0.668 g/gliamocins). In a plug-flow reactor at 150 °C and 500 psi, the apparent maximum yields (0.675 g/gliamocins) are seen at a residence time of 2 h. Overall, this work highlights the use of sustainability and safety criteria in the development of new technologies to produce valuable chemicals from renewable agricultural resources.