Method for preparing combustion inhibitor bisphenol A bis(diphenyl phosphate)

The invention relates to a preparation method for flame retardant bisphenol A bi(diphenyl phosphate). The preparation method comprises the following steps: taking phosphorus oxychloride, bisphenol A and phenol as raw materials, adopting anhydrous zinc chloride or anhydrous aluminum chloride as a main catalyst, and adopting anhydrous calcium chloride or calcium phosphate as a promoter; adding the phosphorus oxychloride, the main catalyst and the promoter into a reactor for intensive stirring, when the materials are heated up to 73 to 78 DEG C, continuously adding bisphenol A, after the addition of bisphenol A is completed within 2.5 to 3 hours, heating up to and maintaining the temperature of 110 to 115 DEG C, and continuing the reaction for 1.5 to 2 hours; leaking out excessive phosphorusoxychloride under the normal and reduced pressure; and cooling down the intermediate product to 100 DEG C, continuous dropping phenol into the intermediate product, heating up to 140 DEG C 2 hours later, carrying out the reac