Solvent‐Free Synthesis of Surfactants of High‐Carbon Alkyl Phosphates Used for Cosmetics

The solvent‐free synthesis of surfactants of high‐carbon alkyl phosphate esters (C = 18, 22) using the polyphosphoric acid method was studied in this work. Phosphoric acid (85 wt%) and phosphorus pentoxide were used to prepare a phosphorylation agent. The preparation conditions of octadecyl and docosyl phosphates were optimized. With the optimized synthesis conditions, the high‐carbon alkyl phosphates were prepared with high yield, and their performances were validated. The results indicate that the high‐carbon alkyl phosphates displayed good emulsifying ability and dispersion performance was compared with the other cosmetic surfactants.