General acid catalysis in benzoic acid-Crystal Violet carbinol base reactions in toluene

2012 ◽  
Vol 44 (8) ◽  
pp. 570-576 ◽  
Author(s):  
Susanta K. Sen Gupta ◽  
Sangeeta Mishra ◽  
V. Radha Rani ◽  
Udai Arvind
Keyword(s):  
Benzoic Acid ◽  
Crystal Violet ◽  
Acid Catalysis ◽  
Acid Crystal ◽  
General Acid

Reactivity of proton and general acid with 1,3-bis-(4-methylphenyl)triazene in aqueous methanol

1990 ◽  
Vol 55 (11) ◽  
pp. 2701-2706 ◽  
Author(s):  
Oldřich Pytela ◽  
Taťjana Nevěčná ◽  
Jaromír Kaválek
Keyword(s):  
Benzoic Acid ◽  
Transition State ◽  
Rate Constant ◽  
Acid Catalysis ◽  
Methanol Concentration ◽  
Binary Solvent ◽  
Aqueous Methanol ◽  
Solvent Water ◽  
General Acid ◽  
Activated Complex

The effect of concentration of benzoic acid and composition of the binary solvent water-methanol on the rate of decomposition of 1,3-bis(4-methylphenyl)triazene has been studied. It has been found that both general acid catalysis by undissociated benzoic acid and catalysis by the proton are significant. The rate constant kHA of general acid catalysis decreases monotonously with decreasing amount of water in the mixture due to preferred solvation of the activated complex as compared with the educts. The rate constant kH of the catalysis by proton in its dependence on methanol concentration exhibits a minimum for 80% (by wt.) of methanol in the mixture. This phenomenon is caused by formation of the conjugated acid from more basic methanol and proton with simultaneous solvation by water and methanol; the particle thus formed is a weaker acid as compared with the complexes existing in water or in methanol. The kH value is higher in methanol than in water due to preferred solvation of the educts as compared with that of the transition state.

Hydrolysis of 4-Nitro-2-(trifluoroacetylamino)benzoic acid: Buffer catalysis, micellar catalysis and intramolecular general acid catalysis

1984 ◽  
Vol 37 (5) ◽  
pp. 977
Author(s):  
TJ Broxton
Keyword(s):  
Benzoic Acid ◽  
Acid Catalysis ◽  
Acidic Solution ◽  
Micellar Catalysis ◽  
Bond Breaking ◽  
Solution Rate ◽  
Solution Ph ◽  
General Acid ◽  
Ph Range ◽  
Hydrolysis Of

The hydrolysis of 4-nitro-2-(trifluoroacetylamino)benzoic acid was studied over the pH range 0-13. In strongly acidic solution (pH 0-3), intramolecular general acid catalysis was observed. In alkaline solution, rate determining protonation of the nitrogen atom of the intermediate complex formed by attack of hydroxide ion on the substrate, was observed. The alkaline hydrolysis was subject to significant micellar catalysis and this was accompanied by a change of mechanism to solvent assisted C-N bond breaking. At intermediate pH (4-8), the reaction was subject to significant buffer catalysis, and deprotonation of the intermediate formed by the attack of water on the substrate was proposed.

General acid catalysis in moderately concentrated aqueous sulphuric acid

1965 ◽  
Vol 39 ◽  
pp. 75 ◽  
Author(s):  
A. J. Kresge ◽  
L. E. Hakka ◽  
S. Mylonakis ◽  
Y. Sato
Keyword(s):  
Sulphuric Acid ◽  
Acid Catalysis ◽  
General Acid
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