On synthesis of BAPO - 5

Two ways of transformation were discovered when using triethylamine as template, to synthesize BAPO - 5 from pseudoboehmite, phosphoric acid and boric acid by means of hydrothermal method. One is producing BAPO - 5 from gel phase directly, the other is producing middle phase first, then producing BAPO - 5 through transformation of crystals slowly. Under the composition condition of the reaction mixture in mole oxide ratio is n(Al2O3):n(P2O5):n(B2O3):n(H2O) = 1:1:0.1:50. That the main factors influence the way of synthesis is the concentration of Et3N and the temperature of crystallization. n(Et3N)/n(Al2O3) = 1, when the temperature of crystallization is 120-150°C, the middle phase molecular sieves CFBAPO - 5 from the gel phase is produced first, then the time of crystallization or the time of crystallization is prolonged and the temperature of crystallization is raised at the same time, CFBAPO - 5 can transform into BAPO - 5; when the temperature of crystallization is 175°C, the temperature of preventing the producing of middle phase will be lower when the concentration of Et3N is higher. Once producing middle phase CFBAPO - 5 during the synthetic process, since transformation of crystals is slowly, there is heterocrystals in the synthetic BAPO - 5 when CFBAPO - 5 can not transform completely. The above results guide to choose the synthetic conditions of BAPO - 5.