Broad-band dielectric spectroscopy on carboxylic acid/water mixtures. Dependence upon composition

Kaatze, U.; Menzel, Katharina; Pottel, R.

doi:10.1021/j100154a059

Cited by 44 publications

(26 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dimer and small cluster units of water that characterize the low- frequency spectra of water exist in the mixtures as fragments of liquid water, and such a unit in the 1:1 mixture must also exist in the intermediate region. This result is in accord with the microphase model of the aqueous mixtures proposed on the basis of ultrasonic absorption measurement 9 Decomposition of the observed R (ν̄) spectra of the binary solutions with x A = 0.015, 0.10, and 0.30 into linear combinations of the R(ν̄) spectra of pure water and the mixture with x A = 0.5.…”

Section: Resultssupporting

confidence: 82%

“…Microphase formation in the binary mixtures is not so surprising in this sense. In Figure , we show a model structure of an acetic acid microphase on the basis of all the spectroscopic data shown in this report and the data by Kaatze et al , The side-on dimer structure is an elementary unit in this model. Along the direction shown by an arrow, acetic acids stack up with alternating orientations of the methyl group to the carboxyl group.…”

Section: Resultsmentioning

confidence: 79%

“…This indicates that the mixtures are composed of microphases of water associates and ethanol associates and there is little contribution to the spectra from ethanol/water complexes. Kaatze and co-workers obtained a similar conclusion on the basis of dielectric spectroscopy of carboxylic acid/water mixtures . They found the presence of two relaxation terms and attributed it to the existence of two microphases, one with high and the other one with low water content.…”

Section: Introductionmentioning

confidence: 66%

See 2 more Smart Citations

Raman Spectroscopic Study on Acetic Acid Clusters in Aqueous Solutions: Dominance of Acid−Acid Association Producing Microphases

1999

View full text Add to dashboard Cite

With the addition of water into liquid acetic acid, the CO stretching vibration band of acetic acid shows a high-frequency shift from 1665 to 1715 cm-1. This means that the hydrogen bond of the CO group of acetic acid is not as strong as those seen in liquid acetic acid or in CCl4 solution (in which the band appears at 1668 cm-1). A bent type hydrogen bond is accountable for this observation. On the other hand, the increase of acetic acid in water drastically decreases the intensity of the hydrogen-bonded O−H stretching Raman band of water at 3200 cm-1. This suggests that acetic acid breaks the hydrogen-bond networks of water. Low-frequency R(ν̄) spectra of acetic acid/water binary solutions are re-examined with new experimental data and ab initio molecular orbital analysis of intermolecular vibrational modes. The R(ν̄) spectrum of the aqueous mixture at x A = 0.5 bears a very close resemblance to that of the acetic acid/methanol mixture with x A = 0.5, indicating that the molecular complexes responsible for the Raman spectra are acetic acid clusters. The calculated low-frequency Raman feature of a side-on type dimer with bent-type hydrogen bonds based on ab initio molecular orbital theory reproduces the observed Raman pattern nicely. Any evidence of the formation of stable acid−water pairs is not found in the low-frequency Raman spectra. Furthermore, an isosbestic point is seen in the region of 0.1 ≤ x A (mole fraction of acetic acid) ≤ 0.5, and another one is also observed in 0.5 ≤ x A ≤ 1.0. The observed spectra in the region of 0 < x A < 0.5 are reproduced simply by linear combinations of the pure water spectrum and the spectrum at x A = 0.5. These results strongly suggest the presence of the two microphases with homogeneously associated molecules: a water cluster phase and an acetic acid cluster phase. The spectral change in 0.5 < x A < 1.0 is attributed to the coexistence of the acetic acid cluster phase in aqueous environment and the acid associated phase characteristic of liquid acetic acid.

show abstract

Section: Resultssupporting

confidence: 82%

Section: Resultsmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 66%

See 1 more Smart Citation

Raman Spectroscopic Study on Acetic Acid Clusters in Aqueous Solutions: Dominance of Acid−Acid Association Producing Microphases

1999

View full text Add to dashboard Cite

show abstract

“…While the aggregation of alcohol molecules are often linked to the anomalous change in several thermodynamic properties, modifications in solution structure are believed to be responsible for the observed sharp change in the ultrasound absorption coefficient of alcoholwater binary mixtures. 9,[35][36] Even though several experimental studies support the idea of formation of clathrate type structures between water and alcohol molecules at very low alcohol concentration, neutron diffraction studies with the lowest alcohol mole fraction have not found any evidence for such a structure.…”

Section: Introductionmentioning

confidence: 99%

Structural transition in alcohol-water binary mixtures: A spectroscopic study

2008

View full text Add to dashboard Cite

The strengthening of the hydrogen bonding (H-bond) network as well as transition from the tetrahedral-like water network to the zigzag chain structure of alcohol upon increasing the alcohol concentration in ethanol-water and tertiary butanol (TBA) -water mixtures have been studied by using both steady state and time resolved spectroscopy. Absorption and emission characteristics of coumarin 153 (C153), a widely used non-reactive solvation probe, have been monitored to investigate the structural transition in these binary mixtures. The effects of the hydrogen bond (H-bond) network with alcohol concentration are revealed by a minimum in the peak frequency of the absorption spectrum of C153 which occur at alcohol mole fraction ~0⋅10 for water-ethanol and at ~0⋅04 for water-TBA mixtures. These are the mole fractions around which several thermodynamic properties of these mixtures show anomalous change due to the enhancement of H-bonding network. While the strengthening of H-bond network is revealed by the absorption spectra, the emission characteristics show the typical non-ideal alcohol mole fraction dependence at all concentrations. The time resolved anisotropy decay of C153 has been found to be bi-exponential at all alcohol mole fractions. The sharp change in slopes of average rotational correlation time with alcohol mole fraction indicates the structural transition in the environment around the rotating solute. The changes in slopes occur at mole fraction ~0⋅10 for TBA-water and at ~0⋅2 for ethanol-water mixtures, which are believed to reflect alcohol mole fraction induced structural changes in these alcohol-water binary mixtures.

show abstract

“…15 Previously, this THz spectral region has been accessed either indirectly through mid-infrared absorption spectroscopy or through Raman scattering techniques. [16][17][18] Early studies, carried out by Waldstein and Blatz and also by Nielsen and Lund, established the fundamental hydrogen bonded modes underlying the THz spectra of formic and acetic acid. 19,20 Later Nishi et al performed a characterization of the low frequency Raman spectrum of neat acetic acid and its alcoholic and aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

Measuring acetic acid dimer modes by ultrafast time-domain Raman spectroscopy

Heisler

Mazur

Yamaguchi

et al. 2011

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Acetic acid is capable of forming strong multiple hydrogen bonds and therefore different dimeric H-bonded structures in neat liquid phase and in solutions. The low frequency Raman spectra of acetic acid (neat, in aqueous solution and as a function of temperature) were obtained by ultrafast time and polarization resolved optical Kerr effect (OKE) measurements. Isotropic OKE measurements clearly reveal a specific totally symmetric mode related to the dimeric structure H-bond stretching mode. The effects of isotope substitution, water dilution and temperature on this mode were investigated. These results together with anisotropic OKE measurements and density functional theory calculations for a number of possible dimers provide strong evidence for the cyclic dimer structure being the main structure in liquid phase persisting down to acetic acid concentrations of 10 M. Some information about the dimer structure and concentration dependence was inferred.

show abstract

Broad-band dielectric spectroscopy on carboxylic acid/water mixtures. Dependence upon composition

Cited by 44 publications

References 5 publications

Raman Spectroscopic Study on Acetic Acid Clusters in Aqueous Solutions: Dominance of Acid−Acid Association Producing Microphases

Raman Spectroscopic Study on Acetic Acid Clusters in Aqueous Solutions: Dominance of Acid−Acid Association Producing Microphases

Structural transition in alcohol-water binary mixtures: A spectroscopic study

Measuring acetic acid dimer modes by ultrafast time-domain Raman spectroscopy

Contact Info

Product

Resources

About