Infrared Study of Acetic Acid Solutions in CCl4

Abstract

Spectra of acetic acid solutions in carbon tetrachloride were taken at room temperature over the concentration range 0.025-0.00125 mol dm-3. Solutions of acetic acid were modelled as an ideal mixture of monomers, and cyclic and linear dimers. Regression analysis effected separation of the experimental envelope into its component bands. Band shapes were approximated by a Lorenzian function with the resolved band peak frequencies 1 712 cm-1 for the cyclic dimer, 1 724 cm-1 for the linear dimer and 1 765 cm-1 for the acetic acid monomer. Mean values of equilibrium constants for the standard state of unit concentration are 2 700 for the cyclic and 393 for the linear dimer, respectively.

Experimental Dipole Moments for Nonisolatable Acetic Acid Structures in a Nonpolar Medium. A Combined Spectroscopic, Dielectric, and DFT Study for Self-Association in Solution

“…ke×E ) N ke×s v s×E (7) Finally, a least-squares minimization of the difference between estimated moles of elements (or chemical groups) N c ke×E and the actual nominal moles of each elements or chemical groups existing in the system N ke×E (due to the initial amounts of solutes used) is used as an objective function (eq 8) to determine d s×s . Simulating annealing is used to achieve this optimization.…”

“…[1][2][3][4] In the gas phase and dilute nonpolar solvent media, the primary acetic acid structures are monomer, cyclic dimer, and open (linear) dimers which are all present in equilibrium. [5][6][7][8][9][10][11][12] Many qualitative and quantitative studies have been carried out using different experimental techniques to understand acetic acid structural forms as well as their compositions in nonpolar media. 7,10,11,13,14 One of the most utilized techniques to reveal the structure of a molecule is through dielectric measurement.…”

“…[5][6][7][8][9][10][11][12] Many qualitative and quantitative studies have been carried out using different experimental techniques to understand acetic acid structural forms as well as their compositions in nonpolar media. 7,10,11,13,14 One of the most utilized techniques to reveal the structure of a molecule is through dielectric measurement. Indeed, some dielectric measurements of acetic acid solutions in some nonpolar solvents have been performed in order to determine the dipole moment of acetic acid monomer and cyclic dimer.…”

Self-Association of Acetic Acid in Dilute Deuterated Chloroform. Wide-Range Spectral Reconstructions and Analysis using FTIR Spectroscopy, BTEM, and DFT

“…The chemistry of carboxylic acids, and in particular the self-association of acetic acid, has also been the subject of numerous spectroscopic and theoretical investigations. − This interest is due in part to the relatively simple structure of acetic acid as well as to the presence of both O···H−O and relatively weaker O···H−C hydrogen bonding. Infrared spectroscopic measurements of acetic acid have been performed in argon and nitrogen matrixes, − ,,, gas phase, ,,, liquid phase, , and solution. − ,,,, These measurements have revealed the presence of several acetic acid species, such as cis- and trans-monomers, cyclic dimer, open (linear) dimers, ,, and higher aggregates. , The matrix isolation spectroscopy investigations have been particularly effective in varying the ratios of monomer to dimer (because of changes in pulse duration etc. ), and this has aided the assignment of infrared bands.…”

“…In part, this is due to the inability to isolate any of the species present and is partly due to ever-present spectral overlap. Conventional band fitting deconvolution techniques are typically utilized to overcome these problems, but this is often restricted to rather narrow spectral windows. ,− ,,, Alternatively, a spectral reconstruction technique could be applied to overcome the problems of multicomponent spectral overlap and the restriction to narrow spectral windows. The resulting pure component spectral estimates can provide a much clearer assessment of the bands present as well their relative intensities.…”