Revealing complex formation in acetone-n-alkane mixtures by MAS PFG NMR diffusion measurement in nanoporous hosts.
Revealing complex formation in acetone-n-alkane mixtures by MAS PFG NMR diffusion measurement in nanoporous hosts.
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通过纳米多孔主体中的 MAS PFG NMR 扩散测量揭示丙酮-正烷烃混合物中复合物的形成。
DOI：
10.1039/b802929f
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
J. Kärger
中科院分区：
文献类型：
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作者：
Moisés Fernandez;A. Pampel;Ryōji Takahashi;S. Sato;D. Freude;J. Kärger
采用魔角旋转脉冲场梯度核磁共振（MAS PFG NMR）技术对丙酮-正构烷烃（C（6）~ C（9））混合物在纳米多孔硅胶中的选择性自扩散进行了研究。两个样品的硅胶与平均孔径约为4和10纳米被认为是。在较小的孔隙中，正烷烃的扩散率约为1，丙酮的扩散率约为2个数量级，小于较大的孔隙。此外，丙酮扩散系数在窄孔试样表现出显着的振荡与增加链长的溶剂正构烷烃：溶解在奇数碳数的正构烷烃的扩散系数超过丙酮溶解在偶数碳数的正构烷烃约50%！这些发现再现了先前宏观释放研究（Phys. Chem. Chem. Phys. 2003，5，2476）中观察到的趋势，并表明在窄孔硅胶中形成丙酮-正烷烃复合物样组合。
Magic-angle spinning pulsed field gradient nuclear magnetic resonance (MAS PFG NMR) was applied for selective self-diffusion measurements of acetone-n-alkane (C(6) up to C(9)) mixtures in nanoporous silica gel. Two specimens of silica gel with mean pore sizes of about 4 and 10 nm are considered. In the smaller pores, the n-alkane diffusivities are by about one and the acetone diffusivities by about two orders of magnitude smaller than in the larger pores. In addition, the acetone diffusivities in the narrow-pore specimen exhibit a pronounced oscillation with increasing chain length of the solvent n-alkanes: the diffusivities of acetone dissolved in odd-carbon number n-alkanes exceed those of acetone dissolved in even-carbon number n-alkanes by about 50%! These findings reproduce the tendencies observed in previous macroscopic release studies (Phys. Chem. Chem. Phys. 2003, 5, 2476) and suggest the formation of acetone-n-alkane complex-like assemblages in the narrow-pore silica gel.