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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ions typically pass with difficulty from water into organic phases because of water's superior solvation power. This inhibits such processes as ion transport in batteries or in lipid bilayers of cells. Ion penetration across such an interface was studied with unusual structural control. Hydronium ions were soft-landed at 1 electron volt on cold films of 3-methylpentane ("oil") on a metal substrate. The field produced by these ions drove them through the films when warmed. Coadsorption of water (0.14 to 35 bilayers) inhibited the ion penetration by creating a solvation energy trap. A Born solvation model successfully predicted the trapping energies (0 to 38 kilojoules per mole).
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PMID:Ion penetration of the water-Oil interface 1061 57

Research of methyl methacrylate (MMA) in three kinds of binary solvent systems (CCl4/C6H14, CHCl3/C6H14 and C2H5OH/C6H14) on the infrared (IR) spectra was reported. Two types of carbonyl stretching vibration bands for MMA in CHCl3/C6H14 or C2H5OH/C6H14 mixtures were found with the changing of the mole fraction of CHCl3 (XCHCl3) or C2H5OH (XC2H5OH). The carbonyl stretching vibration bands at lower frequencies in the above two mixtures were attributed to the formation of hydrogen bonding between MMA and CHCl3 or C2H5OH. While in CCl4/C6H14 mixtures there was only one type of carbonyl stretching vibration band of MMA. Good linear correlations between the frequencies of C=O or C=C stretching vibration band of MMA and XCCl4, XCHCl3 or XC2H5OH were found, respectively. The solute-solvent interactions in the three different binary solvent systems were discussed in detail.
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PMID:Solvent effect on infrared spectra of methyl methacrylate in CCl4/C6H14, CHCl3/C6H14 and C2H5OH/C6H14 binary solvent systems. 1547 53

The glass-forming liquids 3-bromopentane (3BP) and 3-methylpentane (3MP) are readily miscible across the entire composition range, although their polarities differ considerably. As noted by Berberian [J. Non-Cryst. Solids 131-133, 48 (1991)], the nearly matching molar volumes makes this binary system appear ideal for probe-sensitized measurements. We have performed a dielectric study of these mixtures in the range of 3BP mole fractions x from 2 x 10(-4) to 0.75. In the limit of low concentrations, x<0.5%, the dielectric loss peak of 3BP is slower by a factor of 2.5 relative to that of 3MP. Additionally, the relaxation behavior of the guest is more exponential than that of the host liquid. We interpret the distinct dynamics of the guest as a result of temporal averaging over the heterogeneous host dynamics, with the exchange time being near the longest structural time constant of the system.
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PMID:Dynamics of glass-forming liquids. X. Dielectric relaxation of 3-bromopentane as molecular probes in 3-methylpentane. 1626 9

With the recognition that the Debye-type dielectric relaxation of liquid monohydroxy alcohols does not reflect the structural relaxation dynamics associated with the viscous flow and the glass transition, its behavior upon dilution is expected to differ from that of real alpha-processes. We have investigated the Debye-type dielectric relaxation of binary alcohol/alkane mixtures across the entire concentration range in the supercooled regimes. The focus is on 2-ethyl-1-hexanol in two nonpolar liquids, 3-methylpentane and squalane, which are more fluid and more viscous than the alcohol, respectively. The Debye relaxation is found to occur only for alcohol mole fractions x > 0.2 and is always accompanied by a non-Debye relaxation originating from the alcohol component. Prior to its complete disappearance, the Debye relaxation is subject to broadening. We observe that the Debye dynamics of 2-ethyl-1-hexanol is accelerated in the more fluid 3-methylpentane, while the more viscous squalane leads to longer Debye relaxation times. The present experiments also provide evidence that the breakdown of the Debye relaxation amplitude does not imply the absence of hydrogen-bonded structures.
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PMID:Diluent effects on the Debye-type dielectric relaxation in viscous monohydroxy alcohols. 1637 90