α-Oxocarboxylic Acids

Kerber, Robert C.; Fernando, Marian S.

doi:10.1021/ed1003096

Cited by 30 publications

(24 citation statements)

References 51 publications

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“…Even though, one was not able to determine the dissociation constants for compound 4 with accuracy, by analogy with compounds 1–3 , the p K a value of the oxo form (p K a oxo = 1.82) is considerably lower than the value for the hydrated form due to the presence of the electron-withdrawing α-keto group. Kerber and Fernando 11 reported a p K a value for the oxo form of 4 of 1.3. By analogy with carboxylic acids, benzoic acid and acetic acid, the presence of the aromatic ring enhances the deprotonation of the carboxylic group and results in a stronger acid, compared to acetic acid.…”

Section: Resultsmentioning

confidence: 98%

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Determination of pKa and Hydration Constants for a Series of α-Keto-Carboxylic Acids Using Nuclear Magnetic Resonance Spectrometry

Lopalco

Douglas

Denora

et al. 2016

Journal of Pharmaceutical Sciences

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The determination of the acid-base dissociation constants, and thus the pKa values, of α-keto acids such as pyruvic acid is complex due to the existence of these acids in their hydrated and non-hydrated or oxo-state. Equilibria involved in the hydration and dehydration of the α-keto group of pyruvic acid and three other α-keto acids, 3-methyl-2-oxobutanoic acid, 4-methyl-2-oxopentanoic acid, and 2-oxo-2-phenylacetic acid, were investigated by proton and carbon nuclear magnetic resonance spectrometry, NMR, at constant ionic strength, 0.15, and 25°C. Dissociation constants for the oxo (pKaoxo) and hydrated (pKahyd) acids of each compound were estimated from the change in the degree of hydration with changes in pH and directly from the changes in chemical shifts of various hydrogen and carbons nuclei with pH. α-Keto acids showed greater hydration in their acidic forms than their carboxylate forms. The degree of hydration was sensitive to steric and electronic/resonance factors. As expected, the oxo forms of the acids were stronger acids compared with their hydrated analogs, and their dissociation constants were also sensitive to steric and electronic factors.

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Section: Resultsmentioning

confidence: 98%

“…The values represent composite values and reflect the acidities and the relative concentrations of the hydrated and oxo forms of the acids. 11 …”

Section: Introductionmentioning

confidence: 99%

Determination of pKa and Hydration Constants for a Series of α-Keto-Carboxylic Acids Using Nuclear Magnetic Resonance Spectrometry

Lopalco

Douglas

Denora

et al. 2016

Journal of Pharmaceutical Sciences

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“…Conversely, glutaric acid, with relatively high pKa values (pKa 1 = 4.13 and pKa 2 = 5.03), results in barrier oxide formation due to the low solubility of aluminum oxide in this acid. Typically, the carbonyl on the carbon chain of ketoglutaric acid is a powerful electron-withdrawing group and increases the acidity of the electrolyte [46]. Therefore, ketoglutaric acid possesses low pKa values, especially a low pKa 1 , the first dissociation constant.…”

Section: Possibility Of Discovering New Electrolytementioning

confidence: 99%

Growth behavior of anodic oxide formed by aluminum anodizing in glutaric and its derivative acid electrolytes

Nakajima

Kikuchi

Natsui

2014

Applied Surface Science

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The growth behavior of anodic oxide films formed via anodizing in glutaric and its derivative acid solutions was investigated based on the acid dissociation constants of electrolytes. High-purity aluminum foils were anodized in glutaric, ketoglutaric, and acetonedicarboxylic acid solutions under various electrochemical conditions. A thin barrier anodic oxide film grew uniformly on the aluminum substrate by glutaric acid anodizing, and further anodizing caused the film to breakdown due to a high electric field. In contrast, an anodic porous alumina film with a submicrometer-scale cell diameter was successfully formed by ketoglutaric acid anodizing at 293 K. However, the increase and decrease in the temperature of the ketoglutaric acid resulted in non-uniform oxide growth and localized pitting corrosion of the aluminum substrate. An anodic porous alumina film could also be fabricated by acetonedicarboxylic acid anodizing due to the relatively low dissociation constants associated with the acid. Acid dissociation constants are an important factor for the fabrication of anodic porous alumina films.Keywords: Aluminum; Anodizing; Glutaric Acid; Ketoglutaric Acid; Acetonedicarboxylic Acid IntroductionAnodic porous alumina with numerous vertical, nano-scale pores can easily be fabricated via aluminum anodizing in several types of acidic aqueous solutions and has been widely applied in the fields of corrosion protection and electronic applications [1][2][3][4][5][6]. In particular, the development of highly ordered anodic porous alumina, which is fabricated via self-ordering and two-step anodizing under appropriate electrochemical conditions, has expanded the applicability of porous alumina [7]. Accordingly, plasmonic devices [8], antireflection polymer structures[9], optical devices [10], and high-density recording media [11] have been successfully fabricated through the combination of methods for developing highly ordered anodic porous alumina and other nanostructure fabrication techniques.The electrolyte species used for anodic porous alumina fabrication can be specifically classified into the following three groups: inorganic, organic cyclic oxocarbonic, and organic carboxylic acids. It is a well-known experimental fact that anodic porous alumina can be formed by anodizing in these acidic electrolytes, which provide low acid dissociation constants. To date, sulfuric [12][13][14][15][16], selenic [17,18], phosphoric [19,20], and chromic[21] acids have been reported as useful inorganic electrolytes for fabricating anodic porous alumina. The ideal cell arrangement of porous alumina can be achieved via sulfuric, selenic, and phosphoric acid anodizing, whereas poorly ordered porous alumina is fabricated via chromic acid anodizing [22,23]. Cyclic oxocarbonic acids such as squaric [24], croconic, and rhodizonic[25] acid were very recently determined to be suitable organic electrolytes for fabricating porous alumina, although the details of the growth behavior are still unknown. Carboxylic acids can also be employed ...

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“…The 2 Figure 15.2 2-Oxoglutarate can cyclize to form the lactol 2-hydroxy-5-oxotetrahydrofuran-2-carboxylic acid (Kerber and Fernando, 2010). Alternatively, 2OG can be rapidly hydrated to form a ketal, 2,3-dihydroxypentanedioic acid.…”

Section: Biosynthesis Of Coenzyme Mmentioning

confidence: 99%

2-Oxoacid Metabolism in Methanogenic CoM and CoB Biosynthesis

Graham

2011

Methods in Methane Metabolism, Part A

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α-Oxocarboxylic Acids

Cited by 30 publications

References 51 publications

Determination of pKa and Hydration Constants for a Series of α-Keto-Carboxylic Acids Using Nuclear Magnetic Resonance Spectrometry

Determination of pKa and Hydration Constants for a Series of α-Keto-Carboxylic Acids Using Nuclear Magnetic Resonance Spectrometry

Growth behavior of anodic oxide formed by aluminum anodizing in glutaric and its derivative acid electrolytes

2-Oxoacid Metabolism in Methanogenic CoM and CoB Biosynthesis

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