Benzyldimethyl[2-[(1-oxoallyl)oxy]ethyl]ammonium chloride (DAC) is an important cationic monomer that can be homopolymerized or copolymerized with other monomers. It is mainly used as a comonomer in cationic polymerization. It can be copolymerized with acrylamide to produce cationic polyacrylamide, which can be used in the sludge dehydration process of sewage treatment plants and wastewater treatment in papermaking, coal flotation, printing, dyeing and other industries; it can also be widely used in the production of water treatment flocculants, antistatic coatings, papermaking additives, chemicals, fiber additives and other fine molecular products.