Estimation of the degree of hydrogen bonding between quinoline and water by ultraviolet–visible absorbance spectroscopy in sub- and supercritical water

Abstract

Articles you may be interested inInsights into the ultraviolet spectrum of liquid water from model calculations: The different roles of donor and acceptor hydrogen bonds in water pentamers J. Chem. Phys. 137, 184301 (2012); 10.1063/1.4764044 High-resolution ultraviolet spectroscopy of p -fluorostyrene-water: Evidence for a σ -type hydrogen-bonded dimer Structures of hydrogen-bonded clusters of benzyl alcohol with water investigated by infrared-ultraviolet double resonance spectroscopy in supersonic jet J. Chem. Phys. 111, 8438 (1999); 10.1063/1.480184 Microscopic solvent structure of subcritical and supercritical methanol from ultraviolet/visible absorption and fluorescence spectroscopiesAn in situ Raman spectroscopy study of subcritical and supercritical water: The peculiarity of hydrogen bonding near the critical point UV-visible spectra of quinoline was measured in sub-and supercritical water (25°CϽT Ͻ430°C and 0.1 MPaϽ PϽ40 MPa͒, and the degree of hydrogen bonding between quinoline and water was estimated from solvatochromic shifts in the -* absorbance band. Hydrogen bonding decreased with increasing temperature from 25 to 360°C. At supercritical conditions (380°CϽT Ͻ400°C), hydrogen bonding abruptly decreased where the isothermal compressibility of water was large (0.5Ͻ r Ͻ1.5). In this condition, local density around quinoline was lower than bulk density, namely negative solvation, and it led to the cleavage of hydrogen bonding between quinoline and water.

Estimation of Local Density Augmentation and Hydrogen Bonding between Pyridazine and Water under Sub- and Supercritical Conditions Using UV-Vis Spectroscopy

“…2b. Osada et al 34 also reported that the frequency of quinoline, whose molecular structure is similar to pyridazine, does not show any change with temperature (25 -300˚C) in gaseous argon. Thus, the spectral shifts of pyridazine can be attributed mainly to the effect of the polarity of the solvent and hydrogen bonding.…”

“…These phenomena mean that the local density around pyridazine is higher than the bulk density in the supercritical region, as described above. It has been reported that for benzophenone, 33 quinoline, 34 4-nitroaniline, 35 and 4-nitroanisole 40 in supercritical water, the differences between the local density and the bulk density are related to the free volume and the compressibility of the solvent. Therefore, in the liquid state and in a very high-temperature (450˚C) supercritical state, in which the isothermal compressibility is close to zero, the local density should be almost the same as the bulk one.…”

“…The procedure for estimating the local density was referred to in previous studies. [21][22][23][24][25][26][27][31][32][33][34][35] In this work, the equation expressing the spectral shift is determined by fitting the density of water and the experimentally observed frequencies under conditions where the local density can be regarded as the same as the bulk density. The effect of the solvent polarity on the spectral shift has been expressed by the physical properties of the solvent, which are ε and n, as theoretical equations in previous reports.…”

“…22 Bulk density at maximum excess density/g cm -3 the solvent and hydrogen bonding. 51 A procedure proposed by Osada et al 34 for dividing the effect of hydrogen bonding from the spectral shifts was employed in this study. The parameters (A, B, C) in Eq.…”

“…Osada et al 34 determined the parameters of Eq. (2) about quinoline in non-hydrogen bonding solvents under the ambient condition, and suggested a method to estimate the hydrogen-bonding ability of sub-and supercritical water.…”