Hydrolysis of Monothio-β-diketones. I. Monothioacetylacetone and monothiobenzoylacetone

Abstract

The hydrolysis of monothioacetylacetone (4-mercaptopent-3-en-2-one) and monothiobenzoylacetone (3-mercapto-1-phenylbut-2-en-1-one) in acid solution has been studied spectrophotometrically. The half-lives were found to be 50±2 min and 124±5 min at 25° for monothioacetylacetone and monothiobenzoylacetone, respectively. The corresponding pseudo first- order rate constants are 1.39±0.05 x 10^-2 and 5.59±0.14 x 10^-3 min^-1. The enthalpy of activation for the hydrolysis of monothiobenzoylacetone was determined as 79.5 ± 4 kJ/mol.