RATE ENHANCEMENTS DUE TO AQUEOUS SULFURIC ACID IN Mn (III) OXIDATION OF CERTAIN PURINE ALKALOIDS - KINETIC ANALYSIS OF ACIDITY FUNCTIONS

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.

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Acidity functions in 20% ethanol-80% aqueous sulfuric acid

Journal of the American Chemical Society ◽

10.1021/ja00778a041 ◽

1972 ◽

Vol 94 (23) ◽

pp. 8192-8197 ◽

Cited By ~ 8

Author(s):

A. J. Kresge ◽

H. J. Chen

Keyword(s):

Sulfuric Acid ◽

Aqueous Sulfuric Acid ◽

Acidity Functions

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Thiohydantoins. VII. Ionization and ultraviolet spectra of 4-thiohydantoins and 2,4-dithiohydantoins

Canadian Journal of Chemistry ◽

10.1139/v69-181 ◽

1969 ◽

Vol 47 (7) ◽

pp. 1117-1122 ◽

Cited By ~ 5

Author(s):

J. T. Edward ◽

J. K. Liu

Keyword(s):

Sulfuric Acid ◽

Acid Solution ◽

Dissociation Constants ◽

Acid Media ◽

Ultraviolet Spectra ◽

Aqueous Sulfuric Acid ◽

Different Types ◽

Acid And Base ◽

Methyl Derivatives ◽

Acidity Functions

The acid and base dissociation constants of 5,5-pentamethylene-4-thiohydantoin, 5,5-pentamethylene-2,4-dithiohydantoin, and their 1-methyl derivatives, have been determined by ultraviolet studies in basic and acid media. In aqueous sulfuric acid the 4-thiohydantoins are protonated on oxygen at the 2-position, so that the extent of protonation varies with the HA function of the acid solution, while the 2,4-dithiohydantoins are protonated on sulfur at the 2-position, so that the extent of their protonation varies with H0′′′. The importance of using acidity functions appropriate to the different types of compounds when comparing their basicities is emphasized.

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ChemInform Abstract: ACIDITY FUNCTIONS AND THE PROTONATION OF WEAK BASES PART 8, TEMPERATURE VARIATION OF THE H(R) ACIDITY FUNCTION IN AQUEOUS SULFURIC ACID

Chemischer Informationsdienst ◽

10.1002/chin.197518100 ◽

1975 ◽

Vol 6 (18) ◽

pp. no-no

Author(s):

M. J. COOK ◽

N. L. DASSANAYAKE ◽

C. D. JOHNSON ◽

A. R. KATRITZKY ◽

T. W. TOONE

Keyword(s):

Sulfuric Acid ◽

Temperature Variation ◽

Acidity Function ◽

Aqueous Sulfuric Acid ◽

Weak Bases ◽

Acidity Functions

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The cyclization of 2-substituted imidazolines in sulfuric acid

Canadian Journal of Chemistry ◽

10.1139/v94-242 ◽

1994 ◽

Vol 72 (9) ◽

pp. 1910-1914 ◽

Cited By ~ 7

Author(s):

Robin A. Cox ◽

David B. Moore ◽

Robert S. McDonald

Keyword(s):

Sulfuric Acid ◽

Water Molecule ◽

Kinetic Analysis ◽

Ring Closure ◽

Base Catalyst ◽

Aqueous Sulfuric Acid ◽

Medium Acidity

A study of the rates of the cyclizations 1 → 3 and 2 → 4 as a function of medium acidity and temperature in aqueous sulfuric acid has been performed. The latter reaction is five times faster at all acidities. An excess acidity kinetic analysis reveals the probable involvement of a water molecule in the reaction in both cases. Mechanistic possibilities suggested by the observations are discussed; it is proposed that the water molecule acts as a base catalyst during the rate-determining ring closure.

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