Azulene-l-carboxylic acid

01 M perchloric acid, the solvent isotope effect is approximately 2 as expected for a proton transfer from H30+ to a substrate. In more strongly acidic solutions where carbon—carbon bond cleavage is rate- 

Rate coefficients, DjO solvent isotope effects, and carbon-13 isotope effects in the decarboxylation of azulene-l-carboxylic acid and 2,4-dihydroxybenzoic acid in solutions of moderately concentrated strong acids 

In a similar way as for the aromatic amino acids, the change of the rate-determining step is a consequence of the suppression of the ionization of the COOH group of HX+ which causes the concentration of X to become too small to maintain a decomposition rate faster than the rate of C deprotonation. 

According to Schubert and Gardner s results [239], the rate coefficient of decarboxylation of 2,4,6-trihydroxybenzoic acid remains unchanged at ft = ftArcooH = K. kfi in 10 % (1 M) to 38 % aqueous perchloric acid. In the case of 2,4-dihydroxybenzoic acid, however, k rises to values much 

Deviations from eqn. (76) occur at higher concentrations of hydrochloric acid they may be due to medium effects. 

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The observed first-order rate coefficient of the decarboxylation of azulene-l-carboxylic acid [10] at 25 °C as a function of [H+] at a constant ionic strength of / = 0.5 M follows eqn. (13), which is a special case of eqn. (5), viz. 

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