Acidity Dependence of the Tautomeric Equilibrium Between the First Conjugated Acids of 4-Aminoazobenzenes

1979 ◽  
Vol 32 (1) ◽  
pp. 41 ◽  
Author(s):  
S Yamamoto ◽  
Y Tenno ◽  
N Nishimura
Keyword(s):  
Sulfuric Acid ◽  
Tautomeric Equilibrium ◽  
Acid Solutions ◽  
Substituted Anilines ◽  
Aqueous Sulfuric Acid ◽  
Acidity Functions ◽  
Sulfuric Acid Solutions

Acidity functions based upon primary anilines which have no ortho substituents have been established in 20% ethanol-80% aqueous sulfuric acid solutions, and compared with those based upon o-substituted anilines and azobenzenes. It was found that the tautomeric equilibrium between azonium and anilinium forms in 4-aminoazobenzene derivatives invariably shifts to the azonium form with increase in acidity. This observation has been interpreted in terms of acidity functions.

Electrochemistry of Gold in Aqueous Sulfuric Acid Solutions under Neural Stimulation Conditions

2005 ◽  
Vol 152 (7) ◽  
pp. E212 ◽  
Author(s):  
Daniel R. Merrill ◽  
Ionel C. Stefan ◽  
Daniel A. Scherson ◽  
J. Thomas Mortimer
Keyword(s):  
Sulfuric Acid ◽  
Neural Stimulation ◽  
Acid Solutions ◽  
Aqueous Sulfuric Acid ◽  
Sulfuric Acid Solutions

scholarly journals Uptake of hypobromous acid (HOBr) by aqueous sulfuric acid solutions: low-temperature solubility and reaction

2005 ◽  
Vol 5 (6) ◽  
pp. 1577-1587 ◽  
Author(s):  
L. T. Iraci ◽  
R. R. Michelsen ◽  
S. F. M. Ashbourn ◽  
T. A. Rammer ◽  
D. M. Golden
Keyword(s):  
Sulfuric Acid ◽  
Stratospheric Aerosol ◽  
Acid Solutions ◽  
Aerosol Composition ◽  
Gaseous Products ◽  
Aqueous Sulfuric Acid ◽  
Key Species ◽  
Hypobromous Acid ◽  
Equilibrium Concentrations ◽  
Sulfuric Acid Solutions

Abstract. Hypobromous acid (HOBr) is a key species linking inorganic bromine to the chlorine and odd hydrogen chemical families. We have measured the solubility of HOBr in 45-70wt% sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosol composition. Over the temperature range 201-252 K, HOBr is quite soluble in sulfuric acid, with an effective Henry's law coefficient, H*=104-107mol L-1atm-1. H* is inversely dependent on temperature, with ΔH=-45.0±5.4 kJ mol-1 and ΔS=-101±24 J mol-1K-1 for 55-70wt% H2SO4 solutions. Our study includes temperatures which overlap both previous measurements of HOBr solubility. For uptake into 55-70wt% H2SO4, the solubility is described by log H*=(2349±280)/T-(5.27±1.24). At temperatures colder than ~213K, the solubility of HOBr in 45wt% H2SO4 is at least a factor of five larger than in 70wt% H2SO4, with log H*=(3665±270)/T-(10.63±1.23). The solubility of HOBr is comparable to that of HBr, indicating that upper tropospheric and lower stratospheric aerosols should contain equilibrium concentrations of HOBr which equal or exceed those of HBr. Upon uptake of HOBr into aqueous sulfuric acid in the presence of other brominated gases, particularly for 70wt% H2SO4 solution, our measurements demonstrate chemical reaction of HOBr followed by evolution of gaseous products including Br2O and Br2.

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