Acidity function of methanesulfonic acid solutions in DMF

1999 ◽  
Vol 48 (10) ◽  
pp. 1916-1919 ◽  
Author(s):  
I. S. Kislina ◽  
S. G. Sysoeva
1961 ◽  
Vol 14 (2) ◽  
pp. 183 ◽  
Author(s):  
JN Phillips

H- acidity function measurements are reported for aqueous hydrochloric acid solutions using a series of phosphorus-containing acid indicators. The relationship between the H-, Ho, and activity (-log10f�C) function for this system was found to be given approximately by ����������������� �(Ho+H-) ≈ -log10f�CHCl A feature of the results is the weak acidity of concentrated hydrochloric acid solutions in respect of the ionization of a negatively charged base, in contrast to the strong acidity of such solutions in respect of the ionization of a neutral base.


1970 ◽  
Vol 48 (16) ◽  
pp. 2538-2541 ◽  
Author(s):  
R. I. Zalewski ◽  
G. E. Dunn

Protonation of 20 α,β-unsaturated ketosteroids by sulfuric acid was studied by ultraviolet spectrophotometry. Plots of log [B]/[BH+] from spectral data against the amide acidity function, HA, gave straight lines with unit slope. The pKBH+ values thus obtained show the same additive effects of substituents as that reported previously for simple α,β-unsaturated alicyclic ketones.


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 ◽  
...  

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.


1986 ◽  
Vol 64 (6) ◽  
pp. 1224-1227 ◽  
Author(s):  
J. R. Keeffe ◽  
A. J. Kresge ◽  
J. Toullec

Rates of acid-catalyzed enolization of acetophenone in dilute aqueous solution, measured under conditions where the solvated proton is the only acidic species present, give a hydrogen ion catalytic coefficient, [Formula: see text], that is 35% smaller than the value obtained by X acidity function extrapolation of measurements made in moderately concentrated sulfuric acid solutions. The difference may be attributed to catalysis by bisulfate ion in the sulfuric acid solutions; this is supported by direct measurement of the bisulfate ion catalytic coefficient in dilute sulfuric acid. This revised value of [Formula: see text] leads to new, but only slightly different, values of the keto–enol equilibrium constant for acetophenone in aqueous solution, pKE = 7.96 ± 0.04, the acidity constant for acetophenone ionizing as a carbon acid, [Formula: see text] and the encounter-controlled rate constant for the reaction of acetophenone enol with molecular bromine, k = (3.2 ± 0.4) × 109 M−1 s−1.


1951 ◽  
Vol 73 (9) ◽  
pp. 4482-4483 ◽  
Author(s):  
Donald S. Noyce ◽  
Paul Castelfranco

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