Acidity function of perchloric acid in solvent system 50% of ethanol-50% of water

1969 ◽  
Vol 34 (3) ◽  
pp. 1087-1093 ◽  
Author(s):  
P. Vetešník ◽  
K. Rothschein ◽  
J. Socha ◽  
M. Večeřa
Keyword(s):  
Perchloric Acid ◽  
Solvent System ◽  
Acidity Function

Kinetic acidity function Hc.thermod.. 2. The scale in perchloric acid

1979 ◽  
Vol 44 (5) ◽  
pp. 753-757 ◽  
Author(s):  
C. David Johnson ◽  
Shaaron Rose ◽  
Peter G. Taylor
Keyword(s):  
Perchloric Acid ◽  
Acidity Function ◽  
Kinetic Acidity

An acidity scale, [H+]hv, for proton quenching of excited states in aqueous perchloric acid

1989 ◽  
Vol 67 (4) ◽  
pp. 710-719 ◽  
Author(s):  
J. A. Pincock ◽  
P. R. Redden
Keyword(s):  
Excited State ◽  
Activity Coefficient ◽  
Excited States ◽  
Perchloric Acid ◽  
Acidity Function ◽  
Quenching Rate ◽  
Benzyl Alcohols ◽  
Fluorescent Indicator ◽  
Aqueous Perchloric Acid ◽  
Acidity Scale

An acidity scale for excited state protonation kinetics in aqueous perchloric acid has been developed using 1-cyanonaph-thalene as a fluorescent indicator. A comparison of the quenching rate constants obtained using this scale is made with both the more general excess acidity function, X, and the transition state activity coefficient approach. A variety of chromophores were studied including 1- and 2-cyanonaphthalenes, 1- and 2-methoxynaphthalenes, benzyl alcohols, toluenes, benzonitriles, and 2-vinylnaphthalene. Keywords: acidity scale, proton fluorescence quenching.

The Acidity Function of Perchloric Acid in Aqueous Acetic Acid

1954 ◽  
Vol 76 (14) ◽  
pp. 3853-3854 ◽  
Author(s):  
Frederick J. Ludwig ◽  
Kenneth H. Adams
Keyword(s):  
Acetic Acid ◽  
Perchloric Acid ◽  
Aqueous Acetic Acid ◽  
Acidity Function

An acidity function in ethanol – sulfuric acid based on the protonation of diphenylamines

1967 ◽  
Vol 45 (9) ◽  
pp. 903-910 ◽  
Author(s):  
Douglas Dolman ◽  
Ross Stewart
Keyword(s):  
Sulfuric Acid ◽  
Nitro Group ◽  
Strong Interaction ◽  
Acidic Solution ◽  
Sulfuric Acid Concentration ◽  
Substituent Effects ◽  
Solvent System ◽  
Acidity Function ◽  
Substituent Constants ◽  
Hammett Σ Constants

A Hammett H0 acidity function based on the protonation of 17 diphenylamines in 20 volume % ethanol – aqueous sulfuric acid has been established. The H0 value for the most acidic solution studied (11.2 M sulfuric acid) is −6.97. This acidity function differs from that based on the protonation of azobenzenes in the same solvent system; the latter diverges to more negative H0 values as the sulfuric acid concentration increases.The [Formula: see text] values for the protonation of the diphenylamines vary from +1.36 for 4-methoxy-diphenylamine to − 6.21 for 4,4′-dinitrodiphenylamine. A plot of [Formula: see text] versus the Hammett σ constants for five monosubstituted diphenylamines yields a ρ value of +3.36. The [Formula: see text] values for 4-methoxy-, 4-methyl-, 4-methylsulfonyl-, and 4-nitro-diphenylamine are all less (more negative) than expected from the Hammett substituent constants. The substituent effects on the basicities of aniline and diphenylamine are the same.The basicities of several nitro-substituted diphenylamines appear to vary regularly, and do not reflect the presence of a strong interaction between the nitro group and sulfuric acid.

Kinetics of oxidation of bis(ethylenediamine)mercaptoacetatocobalt(III) and cysteinatobis(ethylenediamine)cobalt(III) ions by peroxodisulphate in aqueous-nonaqueous mixed solvents

1986 ◽  
Vol 51 (5) ◽  
pp. 1049-1060 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko ◽  
Ivana Matejeková
Keyword(s):  
Perchloric Acid ◽  
Transfer Functions ◽  
Mixed Solvents ◽  
Sodium Perchlorate ◽  
Activation Parameters ◽  
Solvent System ◽  
Butyl Alcohol ◽  
Complex Ions ◽  
Kinetics Of Oxidation ◽  
Kinetics Of

The kinetics of oxidation in the first step was studied for coordination-bonded sulphur in the cysteinatobis(ethylenediamine)cobalt(III) and bis(ethylenediamine)mercaptoacetatocobalt(III) ions using peroxodisulphate as oxidant. The effect of the acid-base equilibria of the reactants was established based on the dependences of the rate constant and the thermodynamic activation parameters ΔH and ΔS on perchloric acid concentration. The effect of ionic strength at various perchloric acid concentrations, was examined for the two complex ions. The combined effect of perchloric acid and sodium perchlorate was investigated in water-tert-butyl alcohol and water-ethylene glycol solutions. The transfer functions were calculated from the changes in the solubility of the reactants on passing from aqueous to the mixed aqueous-nonaqueous solutions, and the role of solvation during the oxidation of the complexes by peroxodisulphate was assessed based on the dependences of the transfer functions on the nonaqueous component content of the solvent system.

The H− acidity function for dimethylformamide–water

1970 ◽  
Vol 48 (21) ◽  
pp. 3354-3357 ◽  
Author(s):  
E. Buncel ◽  
E. A. Symons ◽  
Douglas Dolman ◽  
Ross Stewart
Keyword(s):  
Solvent System ◽  
Tetramethylammonium Hydroxide ◽  
Acidity Function ◽  
Hydroxide Ion ◽  
Indicator Method ◽  
Aqueous Dimethylsulfoxide

The H− acidity function has been determined for N,N-dimethylformamide–water mixtures containing tetramethylammonium hydroxide by the Hammett indicator method. Basicity in the aqueous dimethylformamide system exceeds that in aqueous tetramethylenesulfone but is slightly less than in aqueous dimethylsulfoxide, at equivalent molar compositions of solvent and base. However, the basic aqueous dimethylformamide solvent system is only of limited utility as a result of reaction of hydroxide ion with the dimethylformamide.

Construction and Chemometric Analysis of Acidity Function in Perchloric Acid

1999 ◽  
Vol 64 (8) ◽  
pp. 1253-1261 ◽  
Author(s):  
Eva Jirásková ◽  
Jiří Kulhánek ◽  
Taťjana Nevěčná ◽  
Oldřich Pytela
Keyword(s):  
Perchloric Acid ◽  
Regression Coefficient ◽  
Principal Component ◽  
Acidity Function ◽  
First Principle ◽  
Protonated Forms ◽  
Aqueous Perchloric Acid ◽  
High Degree ◽  
Degree Of Similarity ◽  
Indicator Type

Four 2,6-disubstituted anilines with CH3, Cl, and NO2 substituents have been synthesized and, together with four commercial substances of the same type, subjected to spectrophotometry to find the concentration ratios of the protonated and non-protonated forms in aqueous perchloric acid of 0.02-10.55 mol dm-3 concentration. By a procedure devised earlier, the acidity function has been constructed and the pKa values calculated. The Principal Component Analysis was applied to the acidity function obtained and on other eight acidity functions of perchloric acid were taken from literature. It was found that the first principal component explained 99.78% of variability, which indicated high degree of similarity of the said functions irrespective of the indicator type and solvent used. The regression dependences acidity function values on the first principle component are very close, the regression coefficient expressing the measure of sensitivity of the indicator to the acidifying medium. The pKa values obtained agree well with the literature data.

The ketonization of acetophenone enol in concentrated aqueous sulphuric and perchloric acid solutions. Implication on X acidity function correlations of the enolization reaction and determination of the keto–enol equilibrium constant as a function of acidity

1990 ◽  
Vol 68 (10) ◽  
pp. 1653-1656 ◽  
Author(s):  
Y. Chiang ◽  
A. J. Kresge ◽  
R. A. More O'ferrall ◽  
B. A. Murray ◽  
N. P. Schepp ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Key Words ◽  
Equilibrium Constant ◽  
Perchloric Acid ◽  
Acidity Function ◽  
Acid Solutions ◽  
Function Correlation ◽  
Aqueous Perchloric Acid ◽  
Sulfuric Acid Solutions

Rates of ketonization of the enol of acetophenone, generated by flash photolytic photohydration of phenylacetylene, were measured in aqueous sulfuric and perchloric acid solutions over the concentration range 1–50 wt.% acid; rates of enolization of acetophenone, monitored by bromine scavenging, were also measured in aqueous perchloric acid solutions over the same concentration range. The results suggest that the curvature observed in a previous X acidity function correlation of the rate of enolization in sulfuric acid solutions was an artifact produced by insufficiently efficient scavenging, and that introduction of the activity of water in the correlating expression, used previously to eliminate the curvature and believed to reflect covalent involvement of water in the enolization reaction, is unnecessary. The present results also show that the keto–enol equilibrium constant for acetophenone decreases with increasing acidity in these concentrated sulfuric and perchloric acid solutions. Key words: acetophenone, enolization, ketonization, keto–enol equilibrium, concentrated acid solutions.

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