Transport of organic solutes through amorphous teflon AF films.
Transport of organic solutes through amorphous teflon AF films.
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DOI：
10.1021/ja052875p
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发表时间：
2005-10
影响因子：
15
通讯作者：
Hong Zhao;Jie Zhang;N. Wu;Xu Zhang;K. Crowley;S. Weber
中科院分区：
文献类型：
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作者：
Hong Zhao;Jie Zhang;N. Wu;Xu Zhang;K. Crowley;S. Weber
含氟介质在选择性萃取（例如应用于有机合成）方面具有很大的潜力。含氟聚合物薄膜在氟分离中具有显著的优势。以聚四氟乙烯af2400为基材，用溶液浇铸稳定膜。薄膜无缺陷（SEM； AFM）。刚性芳香族溶质以尺寸依赖的方式运输（从氯仿溶液到氯仿接收相）（对数渗透率与临界体积的-0.0067倍成正比）。苯的渗透率比可比的气相实验高2个数量级。与含氢对照相比，该膜对氟化溶质具有选择性。传输速率取决于构成源相和接收相的溶剂。有趣的是，溶剂的作用不是由于分配比的变化，而是由于溶质在膜中的扩散系数的变化。溶剂使薄膜增塑。一种挥发性较低的化合物，- cooh端聚（六氟环氧丙烷）(4)，使薄膜增塑化（T(g) = -40℃）。由于溶质的扩散率降低，膜的渗透率明显低于无4膜。测井渗透率随临界体积变化的斜率不变。
Fluorous media have great potential for selective extraction (e.g., as applied to organic synthesis). Fluorous polymer films would have significant advantages in fluorous separations. Stable films of Teflon AF 2400 were cast from solution. Films appear defect-free (SEM; AFM). Rigid aromatic solutes are transported (from chloroform solution to chloroform receiving phase) in a size-dependent manner (log permeability is proportional to -0.0067 times critical volume). Benzene's permeability is about 2 orders of magnitude higher than in comparable gas-phase experiments. The films show selectivity for fluorinated solutes in comparison to the hydrogen-containing control. Transport rates are dependent on the solvent making up the source and receiving phases. The effect of solvent is, interestingly, not due to changes in partition ratio, but rather it is due to changes in the solute diffusion coefficient in the film. Solvents plasticize the films. A less volatile compound, -COOH-terminated poly(hexafluoropropylene oxide) (4), plasticizes the films (T(g) = -40 degrees C). Permeabilities are decreased in comparison to 4-free films apparently because of decreased diffusivity of solutes. The slope of dependence of log permeability on critical volume is not changed, however.