Trimeric quaternary ammonium salt type cationic surface active agent and preparation method thereof

The invention discloses a trimeric quaternary ammonium salt type cationic surface active agent which is shown in a chemical structural formula in the specification, wherein R=-C8H17, -C12H25, -C16H33 or -C18H37; and X=Cl or Br. Moreover, the invention further discloses a preparation method of the trimeric quaternary ammonium salt type cationic surface active agent. The agent is prepared through the quaternary amination reaction of long-chain dimethyl tert-amine and alkyl halide. The preparation method has the advantages of simplicity in operation, inexpensive and easily obtained raw materials, less reaction steps, moderate reaction conditions, easiness in control, low equipment requirements and low preparation cost. Moreover, the novel trimeric quaternary ammonium salt type cationic surface active agent synthesized by the invention has the performances such as high surface activity, good bactericidal performance, strong metal corrosion inhibition and the like, and is particularly suitable for emulsion polymerization of cationic monomers and synthesis of mesoporous materials when being used as an emulsifying agent.