Results 201 to 210 of about 115,096 (255)
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The Second Acidic Constant of Salicylic Acid
Annali di Chimica, 2005AbstractThe second dissociation constant of salicylic acid (H2L) has been determined, at 25 °C, in NaCl ionic media by UV spectrophotometric measurements. The investigated ionic strength values were 0.16, 0.25, 0.50, 1.0, 2.0 and 3.0 M. The protolysis constants calculated at the different ionic strengths yielded, with the Specific Interaction Theory ...
PORTO R, DE TOMMASO G, FURIA, Emilia
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Dissociation constants of carboxymethyloxysuccinic acid
Talanta, 1974The dissociation constants of carboxymethyloxysuccinic acid (CMOS) have been measured at 25 degrees and an ionic strength of 0.1M in sodium perchlorate. The values found were: pK(1) = 2.52, pK(2) = 3.77 and pK(3) = 5.00. CMOS is thus seen to be rather stronger than its isomer citric acid.
C E, Rodriguez, C D, Devine
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Acid Dissociation Constants of Phenylalkanolamines
Journal of Pharmaceutical Sciences, 1962The acid dissociation constants of phenylephrine, synephrine, and tyramine were investigated by the new spectrophotometric method of Edsall. Epinephrine was studied by a titration and complexation method. It is concluded from analysis of the spectral data that the phenolic function is a stronger acid than the alkylammonium group.
S, RIEGELMAN, L A, STRAIT, E Z, FISCHER
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Acidity constant of formic acid
Transactions of the Faraday Society, 1966The acidity constant of formic acid has been re-determined by precise e.m.f. measurements on cells without liquid junctions containing formic acid-sodium formate buffer solutions. The pKa is 3.739±0.001 at 25°C. This result agrees exactly with Saxton and Darken's value obtained by conductivity measurements but not with Harned and Embree's value ...
J. E. Prue, A. J. Read
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Determination of Acidity Constants of Perfluoroalkanoic Acids
Bulletin of the Chemical Society of Japan, 2001Abstract Acidity constants (Ka) of perfluoroalkanoic acids were determined by pH titration and by electric conductivity for shorter alkanoic acids (C1 to C5) with 1 to 5 carbon atoms in the alkyl chain. The acidity constants obtained by the two methods are in good agreement. They increase from C1 (ethanoic) to C3 (butanoic acid) and then
Yoshikiyo Moroi +3 more
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In Silico Calculation of Acidity Constants of Carbonic Acid Conformers
The Journal of Physical Chemistry A, 2010In order to explore the aqueous acid chemistry of carbonic acid, we employ a constrained ab initio molecular dynamics (AIMD) technique to study acid dissociations of its three conformers including CC (cis-cis), CT (cis-trans), and TT (trans-trans). The simulations of reagent states reveal similar hydration characteristics for them: the hydroxyls donate
Xiandong, Liu +3 more
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The acid dissociation constants of 2,3-quinoxalinedithiol
Talanta, 1972Sodium salts of 2,3-quinoxalinedithiol have been prepared and used for determination of the acid ionization constants by potentiometric titration. The fully protonated form of the reagent was used in an alternative determination of the first ionization constant by a solubility method. The constants are pK(2), == 6.84 +/- 0.04 and pK(2) = 9.95 +/- 0.03.
J A, Dalziel, A K, Slawinski
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Dissociation constants of organophosphinic acid compounds
Talanta, 1993The dissociation equilibria of di(2,4,4-trimethylpentyi) phosphinic acid, mono(2,4,4-trimethylpentyl) phosphinic acid, di(n-octyl)phosphinic acid and mono(n-octyl)phosphinic acid have been studied in ethanol-water mixtures by potentiometric titration at 25 degrees C.
M, Martinez +3 more
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Acidity constants of benzidine in aqueous solutions
Talanta, 1987The acidity constants of benzidine (Bz) in aqueous solutions determined potentiometrically at 25 degrees were K(a1) = (1.11 +/- 0.08) x 10(-5), K(a2) = (1.45 +/- 0.12) x 10(-4). The apparent mixed constants in 0.1M sodium nitrate are K(a1) = (5.37 +/- 0.28) x 10(-6) and K(a2) = (1.14 +/- 0.09) x 10(-4).
G B, Reartes, S J, Liberman, M A, Blesa
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Spectrophotometric evaluation of acidity constants of isonicotinic acid
International Journal of Pharmaceutics, 1986Abstract The acid-base equilibria of isonicotinic acid in aqueous media with a constant ionic strength 0.1 at 20 ± 1°C have been spectrophotometrically studied in detail. A new numerical method applicable to the evaluation of overlapping acidity constants has been described.
A.G. Asuero +3 more
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