Serves as an activated monomethyl polyethylene glycol (mPEG) derivative where the terminal hydroxyl group is converted to a p-toluenesulfonate (tosylate) ester, acting as an excellent alkylating agent for nucleophilic substitution reactions in organic synthesis.

Key reagent for PEGylation of biomolecules such as proteins, peptides, antibodies, and small molecules, improving their stability, solubility, circulation time, and bioavailability in pharmaceutical and drug delivery applications.

Employed in surface and material modifications to graft hydrophilic PEG chains, providing anti-fouling, lubrication, and biocompatibility properties for use in coatings, adhesives, biomedical devices, and nanotechnology.

Utilized in the synthesis of PEG-based polymers, surfactants, and functional additives, enabling the production of advanced materials like specialized detergents, emulsifiers, dispersants, and cosmetics ingredients.