Preparation method of methacrylic acid methoxy polyethylene glycol with large molecular weight

The invention belongs to the field of chemical synthesis, and relates to a preparation method of methacrylic acid methoxy polyethylene glycol with large molecular weight. The method adopts 4-dimethylaminopyridine as a catalyst and comprises the following reaction steps: sequentially adding raw materials namely methacrylic acid, dichlorosulfoxide and methoxy polyethylene glycol; adding a polymerization inhibitor and the catalyst namely 4-dimethylaminopyridine; and then adding a solvent, heating at a temperature which is higher than the boiling point of the solvent, also performing condensation refluxing under nitrogen protection, and performing esterification reaction. The esterification reaction in the invention is high in catalysis efficiency and stable in macromonomer quality, and also ensures that produced by-products can be easily removed; and the method disclosed by the invention has wide application prospects in industrial production.