Abstract
In the measurement of the velocity of the decarboxylation of 5-(p-substituted phenyl)-2-oxazolecarboxylic acids, an influence by the solvents and the substituting radicals have been examined.
In the case of solid, it did not show the first order reaction and the velocity became greater as the time elapsed. In the hydrated solvent of ethanol, they showed the first order reaction and the velocity became greater as the content of ethanol increased. By an addition of hydrochloric acid, it became a little greater but the decarboxylation was hardly taken place, when pyridine was added. Either in quinoline or in dichloroacetic acid as a non-aqueous solvent, they showed the first order reaction and the velocity in quinoline was much faster than in dichloroacetic acid. Therefore, the Hammett law has been established among H, CH3S, CH3O and NH2 radicals in quinoline and among Cl, H, CH3S, C6H5, CH3O and OH radicals in dichloroacetic acid. The reaction mechanism was also investigated.
