Decarboxylation of Hydroxybenzoic Acids to Phenol Via Deep Eutectic Solvents

The development of greener and more sustainable synthesis processes for manufacturing commodity chemicals is of great importance. The majority of current phenol production methods involve harsh reaction conditions with high energy consumption, causing severe environmental pollution. In this study, we present a novel approach for the decarboxylation of hydroxybenzoic acids (HBAs) to phenol using a choline chloride-urea (ChCl-urea) deep eutectic solvent (DES). Our study reveals the remarkable dual performance of ChCl-urea both as a catalyst and solvent for the decarboxylation of HBA, resulting in a high phenol yield (94 mol %) under mild reaction conditions. The proposed reaction pathway, established through a combination of experiments and computational simulations, enhances our understanding of this process. The recyclability of the DES system during decarboxylation was also assessed. Our findings demonstrate that the integration of DES into conventional chemical processes can pave the way for sustainable manufacturing, exemplifying a novel approach for producing phenol from abundant natural resources using designer solvents.