Acidity function calculations for perchloric acid

1966 ◽  
pp. 3
Author(s):  
J. G. Dawber
Keyword(s):  
Perchloric Acid ◽  
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

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.

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

The D O acidity function for perchloric acid

1979 ◽  
pp. 272 ◽  
Author(s):  
Robin A. Cox ◽  
Sai-On Lam ◽  
Robert A. McClelland ◽  
Thomas T. Tidwell
Keyword(s):  
Perchloric Acid ◽  
Acidity Function

Carbon protonation of some phenylynamines in concentrated aqueous perchloric acid solution. Lowering of the upper limit for the pKa of phenylynammonium ions

1996 ◽  
Vol 74 (7) ◽  
pp. 1373-1376 ◽  
Author(s):  
A.J. Kresge ◽  
S.W. Paine
Keyword(s):  
Acid Solution ◽  
Perchloric Acid ◽  
Rate Theory ◽  
Acidity Function ◽  
Perchloric Acid Solution ◽  
Hydronium Ion ◽  
Dilute Acid Solution ◽  
Saturated Compound ◽  
Initial States ◽  
Aqueous Perchloric Acid

Rates of carbon protonation of five phenylynamines (PhC≡CNH2, PhC≡CNHiPr, PhC=CNHC6F5, PhC≡CN(CH2CH2CN)2, and PhC≡CNMeC6F5) were determined in concentrated aqueous perchloric acid solution and the data were analyzed by the Cox–Yates method using the X0 acidity function. The extrapolated hydronium-ion catalytic coefficients so obtained are consistent with values measured directly in dilute acid solution, and the slopes of the Cox-Yates plots are similar to predictions made with the aid of Marcus rate theory for reactions originating from free ynamine initial states but unlike those predicted for reactions starting from nitrogen-protonated ynammonium ion initial states. This shows that none of these phenylynamines are protonated in even the most acidic solutions used (4 M) and sets new upper limits as low as pKa ≤ −3.1 for the conjugate acids of these ynamines. Comparison of the pKa limit for PhC≡CNH3+ with a literature value for the corresponding saturated compound, PhCH2CH2NH3+, gives a base-weakening effect for the phenylethynyl group of at least 12.5 pK units. Key words: acetylenic amines, concentrated acids, X0 excess acidity scale, Cox-Yates method, Marcus rate theory.

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