ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Study of acid hydrolysis of some substituted derivatives of 3-phenyliminoxindole
D. Kalavská, S. Kalavský, A. Košturiak, and A. Szaló
Department of Analytical Chemistry, Faculty of Natural Sciences,
Komenský University, 816 50 Bratislava
Abstract: The hydrolysis of ten substituted derivatives of 3-phenyliminoxindole in the
pH region 2.5—5.0 and in the temperature range 10—80°C is described.
The reaction kinetics was investigated spectrophotometrically in the region
300—800 nm within the concentration range 1 x 10-4—6 x 10-4 M in the
presence of 15 volume % of 1-propanol.
The overall rate constants as well as the rate constants of noncatalyzed and
by the H+ ion catalyzed process were determined. The critical concentrations of
catalyst were calculated. The activation parameters of the overall reaction and
catalyzed hydrolysis were determined. The effect of substituent on the rate and
course of hydrolysis was investigated. It has been proved that the acid
hydrolysis of the derivatives of 3-phenyliminoxindole is a first-order reaction in
the whole investigated range of temperature, concentration, and pH. The
results of acid-catalyzed hydrolysis are confronted with the results obtained in
the study of base-catalyzed hydrolysis and a view on the mechanism of
hydrolytic reactions in the whole pH range is put forward.
Full paper in Portable Document Format: 325a650.pdf
Chemical Papers 32 (5) 650–657 (1978)