Original scientific paper

Kinetic Studies on Base-Catalyzed Condensation of BenzaIdehyde, p-Hydroxybenzaldehyde, p-Dimethylaminobenzaldehyde and N,N-Dimethyl-p-nitrosoaniline with l-Phenyl-3-methyl-2-pyrazolin-5-one

M. M. Girgis ; Chemistry Department, Faculty of Science, Assiut University. Assiut, Egypt
R. M. Hassan ; Chemistry Department, Faculty of Science, Assiut University. Assiut, Egypt
Z. H. Khalil ; Chemistry Department, Faculty of Science, Assiut University. Assiut, Egypt

Abstract

The condensation reaction of 1-phenyl-3-methyl-2-pyrazolin-5-one (I) with benzaidehyde (II), p-hydroxybenzaldehyde (III),
p-dimethylaminobenzaldehyde (IV) and N,N-dimethyl-p-nitrosoaniline
(V) in ethanolic media containing piperidine as base catalyst was investigated spectrophotometrically at 10-50oC. It was found that these reactions followed over-all second-order kinetics, first-order with respect to each of the reactants. The results suggest that the rate determining step involves the dehydration of the aldol intermediate (XII). From the dependence of the rate constants on temperature, the thermodynamic parameters of activation were determined and the mechanism which is consistent with the obtained data is discussed.

Keywords

Hrčak ID:

176349

URI

https://hrcak.srce.hr/176349

Publication date:

25.6.1987.

Visits: 935 *