Hydrogen Bonding in Hydrates with one Acetic Acid Molecule

Abstract

Hydrogen bonding (H-bond) interaction significantly influences the separation of acetic acid (HAc) from the HAc/H(2)O mixtures, especially the dilute solution, in distillation processes. It has been examined from the HAc mono-, di-, tri-, and tetrahydrates by analyzing the structures, binding energies, and infrared vibrational frequencies from quantum chemical calculations. For the first coordinate shell the 6-membered head-on ring is surely the most favorable structure because it has (1) the most favorable H-bonding parameters, (2) almost the largest binding energy per H-bond, (3) the biggest wavenumber shifts, and (4) the highest ring distribution (the AIMD simulations). Moreover, the comparison of the calculations with the experiments (the X-ray scattering data and IR frequencies) suggests that the possible structures in dilute aqueous solution are those involving two or more coordinate shells. The H-bonding in these water-surrounded HAc hydrates are the origin of the low-efficiency problem of isolating HAc from the dilute HAc/H(2)O mixtures. It is apparently a tougher work to break the H-bonds among HAc and the surrounded H(2)O molecules with respect to the case of more concentrated solutions, where the dominant structures are HAc or H(2)O aggregates.

Mechanistic insights on C O and C C bond activation and hydrogen insertion during acetic acid hydrogenation catalyzed by ruthenium clusters in aqueous medium

“…was calculated using Henry's a constant K H =2.9 ) obtained from temperature and pressure dependence of H 2 solubility in water (297-616 K, 0-48 bar) [43]. [16,32] 19 [16,61] 290 [16,32,44] 436 [55] 497 [55] 53…”

Correlations between Structure and Near-Infrared Spectra of Saturated and Unsaturated Carboxylic Acids. Insight from Anharmonic Density Functional Theory Calculations

“…Moreover, investigations have been aimed at the nature of the double hydrogen bond emerging between carboxyl groups of cyclic dimers of carboxylic acids. ,− IR and Raman spectroscopies have often been engaged for elucidating the properties of hydrogen-bonded species. − The IR and Raman studies have frequently been supported by quantum chemical calculations. ,− NIR spectroscopy proved to be able to deliver unique insights as well, i.e. by being able to monitor the coexistence of associated and nonassociated species, providing information complementary to the one extracted from IR spectra. ,− Noble gas-matrix isolation studies and quantum chemical calculations have successfully been used, i.e.…”

Theoretical Characterization of Hydrogen Bonding Interactions between RCHO (R = H, CN, CF3, OCH3, NH2) and HOR′(R′ = H, Cl, CH3, NH2, C(O)H, C6H5)

“…[38][39][40] Their further role in protein structure, folding and stability can be well anticipated. 37,[41][42][43] There are numerous reports on hydrogen bonded carbonyl complexes by theoreticians and experimentalists [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] in the past and even today. [62][63][64][65][66][67][68] For example, the earlier work by Bobadova-Parvanova and his co-worker investigated the hydrogen bonded complexes between open-chain substituted aliphatic carbonyl compounds and hydrogen fluoride at the HF/6-31G * * level.…”