Investigated hydrogen-bond network kinetics of acetone-water solutions by spontaneous and stimulated Raman spectroscopy

Abstract

The hydrogen bond (HB) network structure and kinetics of the acetone-water mixed solutions were investigated by the spontaneous Raman and stimulated Raman scattering (SRS) spectra. The HB network of water molecules was enhanced when the volume fraction of acetone ranged from 0 to 0.25. Two new SRS peaks of water at 3272 and 3380 cm−1 were obtained, resulting from the cooperation of the polar carbonyl (C = O)-enhanced HB and the ice-like structure formed around the methyl groups. However, when the volume fraction went beyond 0.25, the spontaneous Raman main peak at 3445 cm−1 showed a significant blue-shift, and the corresponding SRS signal disappeared, indicating that the HB of water was weakened, which originated from the self-association of acetone. In the meantime, the fully tetrahedral HB structure among water molecules was destroyed at the higher volume fraction (≥ 0.8). Hopefully, our study here would advance the study of HB network structures and kinetics in other aqueous solutions.

Solvatochromism in Mixtures of Hydrogen Bond Acceptor (HBA) Solvents with Water

“…The acetone/water mixtures behave similarly to the acetonitrile/water mixtures in terms of the relationships E T (30) as a function of N av,x and refractive index (see Figure S4, SI part). With acetone as a co‐solvent, the situation is further clarified as the enhancement of the water structure has been demonstrated by independent physical measurements [69–71] . The hydrogen bonding network of water molecules in acetone/water mixtures is enhanced when the mole fraction of x(acetone) is between 0 and 0.25, as shown by spontaneous and stimulated Raman spectroscopy [71] .…”

“…With acetone as a co-solvent, the situation is further clarified as the enhancement of the water structure has been demonstrated by independent physical measurements. [69][70][71] The hydrogen bonding network of water molecules in acetone/water mixtures is enhanced when the mole fraction of x(acetone) is between 0 and 0.25, as shown by spontaneous and stimulated Raman spectroscopy. [71] Below x(water) � 0.75 (N av,x = 0.032 mol/ cm 3 ), no enhancement of the water structure is observed in acetone/water mixtures.…”

“…[69][70][71] The hydrogen bonding network of water molecules in acetone/water mixtures is enhanced when the mole fraction of x(acetone) is between 0 and 0.25, as shown by spontaneous and stimulated Raman spectroscopy. [71] Below x(water) � 0.75 (N av,x = 0.032 mol/ cm 3 ), no enhancement of the water structure is observed in acetone/water mixtures. This composition range corresponds to N av,x � 0.05534 to 0.032 mol/cm 3 .…”

“…In the literature, acetonitrile/water mixtures have been analysed from different perspectives, using different physical methods and solvation models. [51][52][53][54][55][56][57][58][59][60][61][62] Acetone/water [63][64][65][66][67][68][69][70][71] and THF/water [72][73][74][75][76][77][78] mixtures have also been well studied by conventional and modern physical methods. Due to the apparent similarity of the thermodynamics of mixing, these three mixtures have often been treated together.…”