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Chemistry

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Mechanism of the benzidine disproportionation of (arylhydrazo)pyridines: the reactions of 4-(4-chlorophenylazo)pyridine and (-hydrazo)pyridine in acid media

Article Abstract:

A product and kinetics analysis has been carried out on reactions of 4-(4-chlorphenylhydrazo)pyridine and 4-(4-chlorphenylazo)pyridine in acid media. Benzidine disproportionation has been studied in these (arylhydrazo)pyridines. In aqueous sulfuric acid, disproportionation of 2 moles of 4-(4-chlorphenylhydrazo)pyridine will yield one mole of the oxidized 4-(4-chlorphenylazo)pyridine, one mole of reduced 4-chloroaniline and one mole of reduced 4-aminopyridine.

Pyridine, Organochlorine compounds, Organic chlorine compounds, Azo compounds

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Kinetics and mechanism of the aminolysis of ethyl aryl carbonates in acetonitrile

Article Abstract:

Aminolysis of ethyl aryl carbonates with benzylamines in acetonitrile has been studied at 25.0 degrees Celsius from the point of view of kinetics and mechanisms. The base-catalyzed path is not present when strong nucleophiles react with a substrate made active by a strong nucleofuge. Results are consistent with transition states with four and six centers for two processes, the uncatalyzed one and the catalyzed one, respectively.

Chemical reactions, Catalysis, Amines, Acetonitrile, Carbonates

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Lactams in sulfuric acid: the mechanism of amide hydrolysis in weak to moderately strong aqueous mineral acid media

Article Abstract:

The mechanism of amide hydrolysis of lactams in weak-to-fairly-strong aqueous mineral acids has been studied using sulfuric acid. The 13C NMR spectra used to determine values of the basicity constants for the substrates are quite sensitive to medium effects. Basicities of lactams for 0.003-0.1 M lactam concentration were more than half a pK unit more alkaline than at 0.5 M lactam. The medium effect is thought to be causative.

Sulfuric acid, Hydrolysis, Amides

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