Abstract

Sayyed Mostafa Habibi-Khorassani*, Mehdi Shahraki and Seyyede Shadfar Pourpanah

DOI : http://dx.doi.org/10.13005/ojc/320332

In this article, UV-vis spectroscopy has been used in order to study the reaction kinetics between benzaldehyde 1, malononitrile 2 and dimedone 3 in a mixture of (ethanol / water, 1:2) as solvents in the presence of caffeine as a biodegradable catalyst. A mechanistic insight into the synthesis of 4H-tetrahydrobenzo[b]pyrans included spectral kinetics approaches is revealed. To investigate the influence of various parameters (temperature, solvent, concentration) on the degradation efficiency and to discuss whether describing the reaction by the means of the pseudo-first order kinetic model is convenient. The overall order of reaction for the formation of tetrahydrobenzo[b]pyran followed second-order kinetics and the partial orders with respect to 1, 2 and 3 were one, one and zero, respectively. The calculation of kinetic parameters would be an integral part of the report. The results showed that the first step of the reaction mechanism is a rate determining step (RDS)) and this is confirmed based upon the steady state approximation.

UV-vis spectroscopy; Caffeine; Catalyst; Kinetics; Mechanistic; Tetrahydrobenzo[b]pyran; pseudo-first order

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