Preparation of methyl ethyl ketone from biomass-derived levulinic acid using a metal-free photocatalytic system and life cycle assessment study†

Levulinic acid (LA) is derived from lignocellulosic biomass and can undergo various chemical transformations to produce high-value chemicals. However, there are limited studies on C–C bond cleavage in LA. Methyl ethyl ketone (MEK) is a high-quality solvent with a wide range of industrial applications, traditionally produced from petroleum-derived n-butene. Here, we report a method for the production of MEK from LA using a metal-free photocatalytic system. Using acridine compounds as photosensitizers and thiophenols as hydrogen transfer reagents, high selectivity and yield of MEK are achieved under mild reaction conditions, and the reaction time is significantly shortened using a microchannel continuous flow photoreactor. Additionally, life cycle assessment indicates that this method has lower carbon emissions than other MEK production methods from LA. This catalytic system provides a green and efficient method to produce MEK from bio-based platform molecule LA, which meets the requirements of sustainable development.