A COMPLETE IONIZATION SCHEME FOR CITRIC ACID

1961 ◽  
Vol 65 (11) ◽  
pp. 2053-2055 ◽  
Author(s):  
R. Bruce Martin
Keyword(s):  
Citric Acid ◽  
Complete Ionization ◽  
Ionization Scheme

ChemInform Abstract: COMPLETE IONIZATION SCHEME FOR CITRIC ACID

1976 ◽  
Vol 7 (5) ◽  
pp. no-no
Author(s):  
KEVIN N. PEARCE ◽  
LAWRENCE K. CREAMER
Keyword(s):  
Citric Acid ◽  
Complete Ionization ◽  
Ionization Scheme

The complete ionization scheme for citric acid

1975 ◽  
Vol 28 (11) ◽  
pp. 2409 ◽  
Author(s):  
KN Pearce ◽  
LK Creamer
Keyword(s):  
Aqueous Solution ◽  
Citric Acid ◽  
Substituent Effect ◽  
Reasonable Agreement ◽  
Methyl Esters ◽  
Careful Consideration ◽  
Acidity Constants ◽  
Complete Ionization ◽  
Ionization Scheme

The microacidity constants for citric acid have been redetermined from pH titrations of citric acid and selected methyl esters in aqueous solution at 25�C and at two ionic strengths. The results obtained differ from those previously published. Calculated acidity constants, derived from a careful consideration of the empirical substituent effect, are also given and are in reasonable agreement with the experimental acidity constants.

Solvent effect on preferred protonation sites in nicotinate and isonicotinate anions

1996 ◽  
Vol 74 (4) ◽  
pp. 613-620 ◽  
Author(s):  
Jean-Claude Hallé ◽  
Jacques Lelievre ◽  
François Terrier
Keyword(s):  
Dimethyl Sulfoxide ◽  
Molecular Form ◽  
Tautomeric Equilibrium ◽  
Benzoic Acids ◽  
Acidity Constants ◽  
Pyridinium Ring ◽  
Substituted Pyridines ◽  
Complete Ionization ◽  
Ionization Scheme ◽  
Pyridinium Cations

Potentiometric determinations of the two successive acidities of nicotinic and isonicotinic acids (AH2+) have been carried out in aqueous dimethyl sulfoxide mixtures containing up to 95% Me2SO by volume. In both systems, the results reveal that the addition of Me2SO induces a proton transfer from the pyridinium ring to the carboxylate group, the tautomeric equilibrium between the neutral forms of the two acids being displaced toward the zwitterionic form (AH±) in aqueous solution, but toward the molecular form (AH°) in Me2SO. An analysis of the data by means of Hammett relationships previously established for benzoic acids over the whole range of H2O/Me2SO mixtures allowed the four microscopic acidity constants as well as the tautomeric equilibrium constant KT pertaining to the complete ionization scheme of the two acids to be determined. At 20 °C, there are equal populations of the tautomeric AH° and AH± species in the mixtures containing 38 and 47% Me2SO for the nicotinic and isonicotinic systems, respectively. Hammett relationships describing the ionization behaviour of a number of substituted pyridinium cations in H2O/Me2SO mixtures are also discussed. Possible reasons accounting for the peculiar effects exerted by the NH2, CONH2, and COOH substituents on the process are suggested. Key words: nicotinic and isonicotinic acids, substituted pyridines, acidities, tautomeric equilibrium, protonation sites, water – dimethyl sulfoxide mixtures.

scholarly journals A Complete Ionization Scheme for Tyrosine, and the Ionization Constants of Some Tyrosine Derivatives

1958 ◽  
Vol 233 (6) ◽  
pp. 1429-1435
Author(s):  
R. Bruce Martin ◽  
John T. Edsall ◽  
Donald B. Wetlaufer ◽  
Barbara R. Hollingworth
Keyword(s):  
Ionization Constants ◽  
Tyrosine Derivatives ◽  
Complete Ionization ◽  
Ionization Scheme

Coadministration of citric acid allows oxytetracycline dose reduction in yellowtail Seriola quinqueradiata infected with Vibrio anguillarum

2020 ◽  
Vol 140 ◽  
pp. 25-29
Author(s):  
K Akiyama ◽  
N Hirazawa ◽  
A Hatanaka
Keyword(s):  
Body Weight ◽  
Citric Acid ◽  
Effective Treatment ◽  
Dose Reduction ◽  
Vibrio Anguillarum ◽  
Enhancing Effect ◽  
Bacterial Diseases ◽  
Seriola Quinqueradiata ◽  
Poor Efficacy

Oxytetracycline (OTC) has been commonly used as an effective antibiotic against various fish bacterial diseases, including vibriosis. In this study, the absorption-enhancing effect of citric acid on oral OTC pharmacokinetics and treatment of artificial Vibrio anguillarum infection was evaluated in juvenile yellowtail Seriola quinqueradiata followed by serum OTC concentration analysis. When 25 mg kg-1 body weight (BW) OTC was administered in combination with 1250 mg kg-1 BW citric acid, the serum OTC concentration reached almost the same concentration as that of the group treated with 50 mg kg-1 BW OTC. This coadministration successfully suppressed mortality due to vibriosis similar to the group treated with 50 mg kg-1 BW OTC. Conversely, poor efficacy was observed when only 25 mg kg-1 BW OTC was administered. These results suggest that coadministration of citric acid can be beneficial in reducing the dose of OTC needed for effective treatment, and thus contributes to the goal of reduced use of this antibiotic in aquaculture.

EFFECT OF SERUM GONADOTROPHIN ON DEHYDROGENASES OF THE CITRIC ACID CYCLE IN THE OVARY OF THE RAT

1963 ◽  
Vol 42 (4) ◽  
pp. 480-484 ◽  
Author(s):  
B. Eckstein ◽  
R. Landsberg
Keyword(s):  
Citric Acid ◽  
Citric Acid Cycle ◽  
Age Groups ◽  
Succinic Dehydrogenase ◽  
Immature Rat ◽  
Acid Cycle ◽  
Immature Rats ◽  
Rat Ovary

ABSTRACT The succinic, malic and isocitric dehydrogenases in the ovary of immature and mature, normal and serum gonadotrophin injected rats were examined. The Qo2 of these enzymes were markedly enhanced in the gonadotrophin injected rats of both age groups, except in the case of succinic dehydrogenase in the ovary of the immature rats, where a slight non-significant decrease was noted. It is concluded that in the mature rat ovary, gonadotrophin administration stimulates the activity of all the examined dehydrogenases of the citric acid cycle, whereas in the immature rat ovary, at least the isocitric- and malic dehydrogenases are thus stimulated.

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