This compound, a tosylate ester of an oligoethylene glycol, is primarily used as an alkylating agent in organic synthesis. It facilitates the introduction of polyethylene glycol (PEG) chains through nucleophilic substitution reactions, commonly in PEGylation processes to modify pharmaceuticals, proteins, and biomolecules for improved solubility, stability, and bioavailability. The reagent is also employed as an intermediate in the preparation of polymers, advanced materials, and fine chemicals, enabling precise functionalization and control in multi-step synthetic pathways.