The Reversible Hydration of Carbonyl Compounds in Aqueous Solution Part II: The Kinetics of the Keto/Gem‐diol Transition

Buschmann, Hans‐Jürgen; Dutkiewicz, Edward; Knoche, Wilhelm

doi:10.1002/bbpc.19820860208

Cited by 74 publications

(123 citation statements)

References 17 publications

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“…UV-spectrophotometric data may be affected both by the uncertainty of the estimate of the molar absorptivity of the unhydrated form and by the limited accuracy of the measurement of the n 6 Β * absorbance at 285 to 290 nm in aqueous solutions 48 . Good agreement has been claimed 50 for data obtained by 19 F NMR in 0.1 M solutions of the ketone in the presence of 0.1 M methanesulfonic acid and data obtained using UV spectra at concentration of the ketone several order of magnitudes smaller in an absence of an added acid. The values of log K h of substituted Τ,Τ-dichloroacetophenones 28 46 are correlated using Φ with ∆ = 1.62, those for substituented Τ,Τ,Τ-trifluoroacetophenones 27 were a linear function of substituent constants Φ + with ∆ + = 1.6, which indicates a resonance interaction between the substituent and the carbonyl group 49 .…”

Section: Covalent Addition Of Water and Alcohols To Aryl Alkyl Ketonessupporting

confidence: 65%

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

Zuman¹

2002

Arkivoc

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In this review are discussed equilibria involved in nucleophilic additions of H 2 O, HO -, ROH, and RO -(where R is an alkyl) to compounds containing carbonyl and azomethine bonds. These reactions result in a formation of covalent bonds between the heteroatom of the nucleophile and the carbon of the carbonyl double bond. After a brief summary of reactions resulting in additions to aliphatic carbonyl compounds, attention is paid to additions to benzaldehydes and formyl aromatic heterocycles. Equilibria involving additions to pyridoxal and some related compounds are dealt with in some detail. Discussion of additions of stated nucleophiles to azomethine bonds is practically restricted to additions to C=N bonds in heterocyclic rings. The reactivity of nucleophiles in such additions depends on the number of heteroatoms (in particular nitrogen) in the attacked ring, as well as on the number and position of substituents in such rings. In polynuclear compounds the reactivity depends on the number and kind of annelled rings, on the number and mutual position of heteroatoms and on the kind, number and position of substituents. In particular additions to pyrimidines, quinazolines, 1,2,4-and 1,3,5-triazines, pteridines and other heterocycles with four nitrogens, as well as 8-azapurines are mentioned.

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Section: Covalent Addition Of Water and Alcohols To Aryl Alkyl Ketonessupporting

confidence: 65%

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

Zuman¹

2002

Arkivoc

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“…Aldehydes and, to a lesser degree, ketones are known to hydrate in aqueous solution (43)(44)(45)(46)(47)(48)(49)(50). It is known that PA is reversibly hydrated in aqueous solution to its gem-diol and that the equilibrium is both pH-and temperature-dependent, with lower pH and lower temperature both favoring the hydrate (51,52).…”

Section: Discussionmentioning

confidence: 99%

“…It is known that PA is reversibly hydrated in aqueous solution to its gem-diol and that the equilibrium is both pH-and temperature-dependent, with lower pH and lower temperature both favoring the hydrate (51,52). In aqueous solution at 298 K, ∼35% of PA exists in its keto form, with the majority existing as its gem-diol (13,45,46). The keto form contains a UV chromophore, which can be excited in the near-UV state to induce photolysis.…”

Section: Discussionmentioning

confidence: 99%

Photochemistry of aqueous pyruvic acid

Griffith

Carpenter

Shoemaker³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

124

289

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The study of organic chemistry in atmospheric aerosols and cloud formation is of interest in predictions of air quality and climate change. It is now known that aqueous phase chemistry is important in the formation of secondary organic aerosols. Here, the photoreactivity of pyruvic acid (PA; CH 3 COCOOH) is investigated in aqueous environments characteristic of atmospheric aerosols. PA is currently used as a proxy for α-dicarbonyls in atmospheric models and is abundant in both the gas phase and the aqueous phase (atmospheric aerosols, fog, and clouds) in the atmosphere. The photoreactivity of PA in these phases, however, is very different, thus prompting the need for a mechanistic understanding of its reactivity in different environments. Although the decarboxylation of aqueous phase PA through UV excitation has been studied for many years, its mechanism and products remain controversial. In this work, photolysis of aqueous PA is shown to produce acetoin (CH 3 CHOHCOCH 3 ), lactic acid (CH 3 CHOHCOOH), acetic acid (CH 3 COOH), and oligomers, illustrating the progression from a three-carbon molecule to four-carbon and even six-carbon molecules through direct photolysis. These products are detected using vibrational and electronic spectroscopy, NMR, and MS, and a reaction mechanism is presented accounting for all products detected. The relevance of sunlight-initiated PA chemistry in aqueous environments is then discussed in the context of processes occurring on atmospheric aerosols.

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“…For example, laboratory studies of MG hydration performed using theoretical (21) and spectroscopic techniques (14,(22)(23)(24) suggest that in aqueous environments MG can become hydrated to form methylglyoxal diol (MGD) via reaction 1 and undergo further reactions to form oligomers (14,21,24). Like other aldehydes and ketones in aqueous solution, MG hydrates through proton addition to the aldehyde carbonyl and reaction to form MGD (21)(22)(23)(25)(26)(27). MG has both an aldehydic and ketonic C ¼ O and it was determined computationally that the aldehydic C ¼ O is more favorably hydrated in solution (ΔG ¼ −1.4 kcal mol −1 ) than the ketonic C ¼ O (ΔG ¼ þ2.5 kcal mol −1 ) (21).…”

mentioning

confidence: 99%

Gas-phase water-mediated equilibrium between methylglyoxal and its geminal diol

Axson

Takahashi

Haan

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

106

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In aqueous solution, aldehydes, and to a lesser extent ketones, hydrate to form geminal diols. We investigate the hydration of methylglyoxal (MG) in the gas phase, a process not previously considered to occur in water-restricted environments. In this study, we spectroscopically identified methylglyoxal diol (MGD) and obtained the gas-phase partial pressures of MG and MGD. These results, in conjunction with the relative humidity, were used to obtain the equilibrium constant, K P , for the water-mediated hydration of MG in the gas phase. The Gibbs free energy for this process, ΔG°, obtained as a result, suggests a larger than expected gas-phase diol concentration. This may have significant implications for understanding the role of organics in atmospheric chemistry.hydration | equilibrium constant | water clusters

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The Reversible Hydration of Carbonyl Compounds in Aqueous Solution Part II: The Kinetics of the Keto/Gem‐diol Transition

Cited by 74 publications

References 17 publications

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

Photochemistry of aqueous pyruvic acid

Gas-phase water-mediated equilibrium between methylglyoxal and its geminal diol

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