Dissociation constants of monosubstituted diphenylamines and an optimized construction of acidity function

1983 ◽  
Vol 48 (8) ◽  
pp. 2368-2375 ◽  
Author(s):  
Oldřich Pytela ◽  
Pavel Vetešník
Keyword(s):  
Free Energy ◽  
Sulphuric Acid ◽  
Concentration Ratio ◽  
Dissociation Constants ◽  
Acidity Function ◽  
Linear Free Energy Relationships ◽  
Linear Free Energy ◽  
Energy Relationships ◽  
Sulphuric Acid Concentration

Eleven monosubstituted diphenylamines have been synthetized, and concentration ratio of the protonated and free bases has been measured in aqueous sulphuric acid in the concentration range 1.0 . 10-3 to 9.0 mol l-1. An algorithm has been suggested and used for determination of optimized values of pK and H'' acidity function within sulphuric acid concentration range 0.05 to 9.0 mol l-1. The results have been compared with literature data and discussed in terms of theory of acidity functions and linear free energy relationships.

LINEAR FREE ENERGY RELATIONSHIPS CONCERNING EQUILIBRIA IN MODERATELY CONCENTRATED MINERAL ACIDS: A SIMPLE METHOD FOR ESTIMATING pK's OF WEAK BASES

1966 ◽  
Vol 44 (16) ◽  
pp. 1899-1916 ◽  
Author(s):  
J. F. Bunnett ◽  
Fredric P. Olsen
Keyword(s):  
Free Energy ◽  
Acid Concentration ◽  
Standard Form ◽  
Acidity Function ◽  
Linear Free Energy Relationships ◽  
Simple Method ◽  
Linear Free Energy ◽  
Equilibrium Quotient ◽  
Mineral Acids ◽  
Energy Relationships

Linear relationships exist between the logarithms of equilibrium quotients, [SH+]/[S][H+], of diverse bases as they vary with acid concentration in moderately concentrated mineral acids. For purposes of formulating these linear free energy relationships in standard form, the equilibrium quotient for protonation of a hypothetical aromatic primary amine of pKa zero has been chosen as horizontal coordinate; this is given by (−H0 − log [H+]). Log ([SH+]/[S]) + H0 is plotted against (H0 + log [H+]). The slope, [Formula: see text] of the linear plot is a parameter which characterizes the response of the equilibrium quotient to changing acid concentration. The intercept represents the thermodynamic pKa of the base. This constitutes a general method for estimating the pKa of any base which undergoes protonation in moderately concentrated mineral acid, with reference to the single acidity function, H0. For bases of diverse type, pK's estimated by this method are in good agreement with those estimated by the acidity function method. Use of the new correlation procedure as a check on the validity of several acidity functions and its application to equilibria not involving proton gain or loss are also discussed.

Applicability of the HT acidity function to the protonation of thioamides, thioureas, and thionesters

1977 ◽  
Vol 55 (12) ◽  
pp. 2331-2335 ◽  
Author(s):  
John T. Edward ◽  
Gary D. Derdall ◽  
Sin Cheong Wong
Keyword(s):  
Free Energy ◽  
Sulfuric Acid ◽  
Protonation Constants ◽  
Acidity Function ◽  
Linear Free Energy Relationships ◽  
Acceptable Accuracy ◽  
Aqueous Sulfuric Acid ◽  
Linear Free Energy ◽  
Energy Relationships

The protonation of eleven thioamides, five thioureas, and four thionbenzoates in aqueous sulfuric acid has been found to follow the HT acidity function with acceptable accuracy. Protonation constants pKTH+ obtained by use of HT agreed fairly well with pKTH+ values obtained by the Bunnett–Olsen method, but less well with those obtained by the Marziano–Cimino–Passerini procedure. Linear free-energy relationships of pKTH+ values are discussed.

Linear free energy relationships in CN bond dissociations in molecular ions of 4-substitutedN-(2-furylmethyl)anilines in the gas phase

2007 ◽  
Vol 42 (11) ◽  
pp. 1496-1503 ◽  
Author(s):  
Eduardo A. Solano Espinoza ◽  
Elena Stashenko ◽  
Jairo Martínez ◽  
Uriel Mora ◽  
Vladimir Kouznetsov
Keyword(s):  
Free Energy ◽  
Gas Phase ◽  
Molecular Ions ◽  
Linear Free Energy Relationships ◽  
Linear Free Energy ◽  
Energy Relationships
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