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为了探讨化学成份对VPO体系孔道结构化合物结构稳定性的影响,根据酸碱平衡原理进行了合成实验设计;利用V2O5、H3PO4、H3BO3 等简单的无机前驱物、乙二胺作结构导向剂,水热法合成了孔道结构钒硼磷酸盐化合物(H3NCH2CH2NH3 )2 (H3NCH2CH2NH2 ) [VⅢ (H2O)2 (VⅣO)8 (OH)4 (H(P,B)O4 )4 ( (P,B)O4 )4 (H2O)2 ]·3H2O(简称V9 (P,B)8 en)。典型的反应起始物摩尔比为n(V2O5 ):n(H3BO3 ):n(H3PO4 ):n(en):n(H2O) =0. 89:3. 50: 3. 50: 3. 60: 265(pH值为 6. 5),在 175℃、自生压力条件下恒温晶化 6. 5d(最终pH值为 5. 9 )。通过电子探针、粉末X射线衍射、红外吸收光谱、原子占位度修正等方法,对产物的化学成份、物相及其结构等进行了实验研究。证实V9 (P,B)8 en为V9P8 en的类质同象化合物,不同晶粒中B与P的含量有差别,B与P之比为 0. 1: 7. 9~2. 54: 5. 46(原子比),但恒有V: (P+B)≈9: 8。表明通过合理设计和控制合成条件,可在保持V9P8 en基本结构不变的前提下通过同晶取代引入新的化学成份,并由此探讨成份与结构稳定性的关系。
In order to study the influence of chemical composition on the structural stability of the pore structure compounds of VPO system, a synthetic experimental design was carried out according to the principle of acid-base equilibrium. Using simple inorganic precursors such as V2O5, H3PO4 and H3BO3, ethylenediamine as structure-directing agent, (H3P2O4) 4 ((P, B) O4) 4 (H3NCH2CH2NH3) 2 (H3NCH2CH2NH2) [VIII (H2O) 2 (VIVO) 8 (OH) 4 (H2O) 2] · 3H2O (abbreviated as V9 (P, B) 8 en). Typical reaction starting material molar ratios are n (V2O5): n (H3BO3): n (H3PO4): n (en): n (H2O) = 0.89: 3.50: 3.50: 3.60: 265 (pH 6. 5), at 175 ° C under autogenous pressure at a constant temperature crystallization 6. 5d (final pH value of 5.9). The chemical composition, phase and structure of the product were studied by means of electron probe, powder X-ray diffraction, infrared absorption spectroscopy and atom occupancy correction. It was confirmed that V9 (P, B) 8 en is an isomorphic compound of V9P8 en, with different contents of B and P in different grains, the ratio of B to P being 0.1: 7. 9 to 2. 54: 5 46 (atomic ratio), but constant V: (P + B) ≈9: 8. The results show that through the reasonable design and control of the synthesis conditions, new chemical components can be introduced by isomorphous substitution while keeping the basic structure of V9P8en unchanged, and the relationship between the composition and the structural stability is discussed.