Investigation of acetic acid hydration shell formation through Raman spectra line-shape analysis.
Raman spectra of acetic acid aqueous solutions in the 500-4000 cm(-1) range have been measured as a function of water concentration to investigate the hydration shell formation mechanism around the acetic acid molecules. A fitting procedure based on the Kubo-Anderson model has been applied to the spectra. This has allowed us to determine the average lifetime of the hydrogen bonds involving a given functional group, as well as their geometrical distribution as a function of water concentration. The comparison of our results with literature data has demonstrated that the fitting model is adequate to describe organic water mixtures. Finally, the role of water in the formation of the hydrophobic shell around the methyl group in diluted acetic acid water solutions has been discussed, evidencing how the methyl group hydrophobicity strongly influences the acetic acid behavior in aqueous solutions.
Sincrotrone Trieste, Strada Statale 14 km 163.5, Area Science Park, I-34012 Trieste, Italy. francesco.damico@elettra.trieste.it
Francesco
F
D'Amico
Filippo
F
Bencivenga
Alessandro
A
Gessini
Emiliano
E
Principi
Riccardo
R
Cucini
Claudio
C
Masciovecchio
D019342:Acetic Acid / Q000737:chemistry*; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008956:Models, Chemical; D013059:Spectrum Analysis, Raman; D014867:Water / Q000737:chemistry*
D014867:Water; D019342:Acetic Acid