H₃PO₄/metal halide induces a one-pot solvent-free esterification-halogenation of glycerol and diols

As part of our continued effort to achieve the synthesis of halohydrin esters from polyols by a sustainable method, here we report on a multicomponent inorganic acid-mediated solvent-free synthesis. The synthesis was designed to ensure few waste materials. Using this approach, the process shows a low E-factor and a high reaction mass efficiency. The new process involves the preparation of a reaction mixture containing either a fatty acid or fatty material, glycerol or diol, a halide salt and H₃PO₄. This mixture is heated at 100°C for 48 h, yielding up to 88% of halohydrin ester. The process also allows recovery of pyrophosphate salts, compounds that have various applications in agriculture, and in the pharmaceutical, chemical and food industries.