Hydronium Ion Acidity Above and Below the Interface of Aqueous Microdroplets

Rate constants measured with the flowing afterglow technique at 298 ± 2 K are reported for the proton-transfer reactions of H3O+ with CH2O, CH3CHO, (CH3)2CO, HCOOH, CH3COOH, HCOOCH3, CH3OH, C2H5OH, (CH3)2O, and CH2CO. Dissociative proton-transfer was observed only with CH3COOH. The rate constants are compared with the predictions of various theories for ion–molecule collisions. The protonation is discussed in terms of the energetics and mechanisms of various modes of dissociation.

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TUNGSTEN OXIDES AND BRONZES: SYNTHESIS, DIFFUSION AND REACTIVITY

International Journal of Modern Physics B ◽

10.1142/s0217979293003607 ◽

1993 ◽

Vol 07 (23n24) ◽

pp. 4145-4164 ◽

Cited By ~ 27

Author(s):

JING-DONG GUO ◽

M. STANLEY WHITTINGHAM

Keyword(s):

Tungsten Bronze ◽

Pyrochlore Phase ◽

Reaction Medium ◽

Pyrochlore Structure ◽

Ionic Mobility ◽

Soft Chemistry ◽

Quarter Century ◽

Tungsten Oxides ◽

Hydronium Ion ◽

Wide Range

The tungsten oxides and bronzes have been extensively studied since their discovery in the last century, because of their brilliant colors and high electrical conductivity. More recently the driving interest resulted from their potential use in electrochromic displays and other electrochemical systems. Their crystalline structures are generally based on the corner sharing of WO 6 octahedra giving tunnels of variable size and shape leading to exciting intercalation chemistry. These structures readily undergo redox reactions, and in the last quarter century these reactions have often involved soft chemistry. Most recently hydrothermal techniques have been used to prepare new sodium tungstates with the hexagonal tungsten bronze and the pyrochlore structures. The phase formed is a function of the pH of the reaction medium. The pyrochlore phase readily undergoes ion-exchange with a wide range of monovalent cations giving the compounds, M x W 2 O 6+x/2 · y H 2 O ; the value of y is strongly dependent on the identity of the cation, M. WO 3 with the pyrochlore structure could be formed from the hydronium and ammonium complexes. Lithium can be readily intercalated either chemically and electrochemically into both these phases, just as in the previously-known bronze phases. Surprisingly more lithium is incorporated in most cases in the hexagonal than in the pyrochlore phase. The ions in the pyrochlore structure show rapid ionic mobility, with the hydronium ion showing the greatest mobility.

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Separation of the partial currents for reduction of hydronium ion and water in dilute strong acid solutions using the sinusoidal hydrodynamic modulation method

Journal of Electroanalytical Chemistry ◽

10.1016/s0022-0728(84)80043-1 ◽

1984 ◽

Vol 163 (1-2) ◽

pp. 77-92 ◽

Cited By ~ 6

Author(s):

S. Swathirajan ◽

Stanley Bruckenstein

Keyword(s):

Strong Acid ◽

Modulation Method ◽

Acid Solutions ◽

Hydronium Ion ◽

Hydrodynamic Modulation ◽

Partial Currents

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Spectroscopic BIL-SFG Invariance Hides the Chaotropic Effect of Protons at the Air-Water Interface

Atmosphere ◽

10.3390/atmos9100396 ◽

2018 ◽

Vol 9 (10) ◽

pp. 396 ◽

Cited By ~ 7

Author(s):

Simone Pezzotti ◽

Marie-Pierre Gaigeot

Keyword(s):

Water Structure ◽

Md Simulations ◽

Interfacial Structure ◽

Water Interface ◽

Sum Frequency ◽

Hydronium Ion ◽

Sum Frequency Generation Spectroscopy ◽

Air Water Interface ◽

Ph Conditions ◽

Shed Light

The knowledge of the water structure at the interface with the air in acidic pH conditions is of utmost importance for chemistry in the atmosphere. We shed light on the acidic air-water (AW) interfacial structure by DFT-MD simulations of the interface containing one hydronium ion coupled with theoretical SFG (Sum Frequency Generation) spectroscopy. The interpretation of SFG spectra at charged interfaces requires a deconvolution of the signal into BIL (Binding Interfacial Layer) and DL (Diffuse Layer) SFG contributions, which is achieved here, and hence reveals that even though H 3 O + has a chaotropic effect on the BIL water structure (by weakening the 2D-HBond-Network observed at the neat air-water interface) it has no direct probing in SFG spectroscopy. The changes observed experimentally in the SFG of the acidic AW interface from the SFG at the neat AW are shown here to be solely due to the DL-SFG contribution to the spectroscopy. Such BIL-SFG and DL-SFG deconvolution rationalizes the experimental SFG data in the literature, while the hydronium chaotropic effect on the water 2D-HBond-Network in the BIL can be put in perspective of the decrease in surface tension at acidic AW interfaces.

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