The invention provides a synthetic method of 2-methyl-4-chloropropionic acid-
polyethylene glycol ester, and belongs to the technical field of preparation of 2-methyl-4-chloropropionic acid-
polyethylene glycol ester. The method comprises the following steps: adding o-
cresol,
dichloroethane and a catalyst, and reacting
sulfuryl chloride at the temperature of below 15 DEG C; performing separation to obtain p-chloro-o-
cresol and 6-chloro-o-
cresol; adding p-chloro-o-cresol, 2-chloropropionic acid and caustic soda liquid to synthesize 2-methyl-4-chloropropionic acid; 2-methyl-4-chloropropionic acid is acidized, cooled, crystallized and sliced, 2-methyl-4-chloropropionic acid,
polyethylene glycol and a neutral catalyst are added for a reaction, and the di-2-(4-chloro-2-methyl-phenoxy) propionic acid-
polyethylene glycol ester is synthesized. The method is simple in process, mild in reaction and high in yield. By means of the synthesis method, a qualified product with the p-chloro-o-cresol content larger than 99% can be produced, other
phenol impurities are not contained, the synthesis quality of p-chloro-o-cresol is guaranteed, meanwhile, synthesis of 2-methyl-4-chloropropionic acid-
polyethylene glycol ester is easier to control, the product quality can be greatly improved, and meanwhile the domestic blank is filled up.