Structural (XRD) and thermal (DSC, TGA) and BET analysis of materials derived from non-metal cation pentaborate salts
作者:Michael A. Beckett、Peter N. Horton、Michael B. Hursthouse、David A. Knox、James L. Timmis
DOI:10.1039/b927072h
日期:——
The synthesis, structural characterization (XRD), and thermal properties of nine non-metal cation (NMC) pentaborate anion salts, [NMC][B5O6(OH)4] (1a–1i) is described (NMC = [NH3CMe2(CH2OH)]+ (a), [O(CH2CH2)2NH2]+ (b), [NH3CMe(CH2OH)2]+ (c), [2-(2-CH2CH2OH)PyH]+ (d), [(CH2)4NH(CH2CH2OH)]+ (e), [(CH2)5NH(CH2CH2OH)]+ (f), [2-MeImid]+ (g), [Me3NCMe2(CH2OH)]+ (h), [O(CH2CH2)2NMe2]+ (i). Single-crystal X-ray diffraction studies on all compounds show that they contain isolated pentaborate anions, H-bonded together in a supramolecular array, with the cations occupying the cavities within the network. Compound 1c was obtained as a partial hydrate (0.16H2O). TGA and DSC analysis (in air, 25–1000 °C) indicate that compounds 1a–1i thermally decompose via a 2 stage process to B2O3. The first stage (<250 °C) is dehydration to condensed polymeric pentaborates approximate composition: [NMC][B5O8] (2a–2i)}. Five condensed pentaborates (2a–c, 2e, 2g) were synthesised and characterized by powder XRD and BET analysis. These condensed pentaborates were amorphous. The isolated pentaborates intumesced at ∼600 °C (occupying ∼10 times their original volume), and then contracted back to black glassy B2O3 solids at 1000 °C. The intumescent materials (3a), (3b), (3e), (3g), and a final B2O3 sample (4b) were synthesised and isolated and their porosities determined. BET surface area analysis on the isolated pentaborates (1a–c, 1e, 1g), the condensed pentaborates (2a–c, 2e, 2g), intumesced materials (3a, 3b, 3e, 3g), and B2O3 (4b) showed that they were all ‘non-porous’ (<1.59 m2 g−1).
九种非金属阳离子(NMC)的五硼酸盐阴离子盐[NMC][B5O6(OH)4](1a–1i)的合成、结构表征(XRD)和热性质(NMC = [NH3CMe2(CH2OH)]+(a), [O(CH2CH2)2NH2]+(b), [NH3CMe(CH2OH)2]+(c), [2-(2-CH2CH2OH)PyH]+(d), [(CH2)4NH(CH2CH2OH)]+(e), [(CH2)5NH(CH2CH2OH)]+(f), [2-MeImid]+(g), [Me3NCMe2(CH2OH)]+(h), [O(CH2CH2)2NMe2]+(i)。所有化合物的单晶X射线衍射研究表明,它们含有孤立的五硼酸盐阴离子,通过氢键结合在一起形成超分子排列,阳离子位于网络中的空腔内。化合物1c以部分水合物(0.16H2O)形式获得。TGA和DSC分析(在空气中,25–1000°C)表明,化合物1a–1i通过两阶段过程热分解为B2O3。第一阶段(<250°C)是脱水形成凝聚聚合五硼酸盐近似组成:[NMC][B5O8](2a–2i)}。合成了五种凝聚五硼酸盐(2a–c, 2e, 2g)并通过粉末XRD和BET分析进行了表征。这些凝聚五硼酸盐是无定形的。孤立的五硼酸盐在约600°C时膨胀(占据约原始体积的10倍),然后在1000°C时收缩回黑色玻璃状B2O3固体。合成了膨胀材料(3a), (3b), (3e), (3g)和最终的B2O3样品(4b)并进行了分离,并测定了它们的孔隙度。对孤立的五硼酸盐(1a–c, 1e, 1g)、凝聚五硼酸盐(2a–c, 2e, 2g)、膨胀材料(3a, 3b, 3e, 3g)和B2O3(4b)的BET比表面积分析显示,它们都是“非多孔”的(<1.59 m2 g−1)。