KINETIC ASPECTS OF 3, 4 dihydropyrano[c]chromenes FORMATION IN THE PRESENCE OF DIFFERENT CATALYSTS: A MECHANISTIC INVESTIGATION
BAHAREH MOSTAFA
Department of Chemistry, Faculty of Science, University of Sistan and Baluchestan, P.O.Box 98135-674, Zahedan, Iran
SAYYED MOSTAFA HABIBI-KHORASSANI *
Department of Chemistry, Faculty of Science, University of Sistan and Baluchestan, P.O.Box 98135-674, Zahedan, Iran
MEHDI SHAHRAKI
Department of Chemistry, Faculty of Science, University of Sistan and Baluchestan, P.O.Box 98135-674, Zahedan, Iran
*Author to whom correspondence should be addressed.
Abstract
A kinetic study of reaction between benzaldehyde, malononitrile and 4-hydroxycoumarin compounds has been established spectrally in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) and sodium acetate as a catalyst. Based on the experiment data, reaction followed second order rate law. The rate law that deduced from the mechanism was compatible with the observed rate law. The results showed that the first step of the reaction mechanism was a rate-determining step. Experimental effects of catalysts, solvent, concentration and functional group (structural effect) on the reaction rate provided useful information regarding the mechanism of reaction.
Keywords: Kinetics, mechanism, catalyst, dihydropyrano derivatives