The application of tetraphenylphosphonium bromide is a phase transfer catalyst (Phasetransfercatalyst) is a new technology developed in the past two decades, because it overcomes the shortcomings of the need for polar aprotic solvents in heterogeneous organic synthesis Chemicalbook, and can make heterogeneous reactions should be carried out under relatively mild conditions, accelerate the reaction rate and improve yield, thus playing a great role in promoting the development of organic synthesis.