BAPO-5的合成研究

发现用三乙胺 (Et3N)做模板剂 ,由拟薄水铝石、磷酸和硼酸水热合成BAPO -5时 ,存在两条转化路线 ,一条是由凝胶相直接生成BAPO -5,另一条是首先生成中间相 ,然后缓慢转晶生成BAPO -5。在反应混合物配料比为n(Al2 O3)∶n(P2 O5)∶n(B2 O3)∶n(H2 O) =1∶1∶0 .1∶50的条件下 ,影响转化路线的主要因素是Et3N的浓度和晶化温度。n(Et3N) /n(A1 2 O3) =1 ,晶化温度为 1 2 0～ 1 50℃ ,首先由凝胶相生成中间分子筛相CFBAPO -5,再延长晶化时间 ,或延长晶化时间同时升高晶化温度 ,CFBAPO -5可转晶生成BAPO -5;晶化温度为 1 75℃ ,则凝胶相直接生成BAPO -5。n(Et3N) /n(A1 2 O3) =1 .5,1 50℃晶化 ,凝胶相直接晶化为BAPO -5,抑制中间相生成的温度随Et3N浓度增加而下降。在合成BAPO -5时 ,一旦有中间相CFBAPO -5生成 ,由于转晶过程缓慢 ,在不能实现完全转晶条件下 ,合成的BAPO -5中存在杂晶。以上结果对合成BAPO -5条件选择具有指导意义。

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 (Al 2O 3)∶ n (P 2O 5)∶ n (B 2O 3)∶ n (H 2O)=1∶1∶0.1∶50. That the main factors influence the way of synthesis is the concentration of Et 3N and the temperature of crystallization. n (Et 3N)/ n (Al 2O 3)=1, when the temperature of crystallization is 120～150 ℃, 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 ℃, the temperature of preventing the producing of middle phase will be lower when the concentration of Et 3N 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 guid to choose the synthetic conditions of BAPO-5.