Kinetic Aspects of Tetrahydrobenzo[b]pyran Formation in the Presence of Agar as a Green Catalyst: A Mechanistic Investigation

Mehdi Shahraki, Sayyed Mostafa Habibi-Khorassani, Sayyedeh Shadfar Pourpanah
2016 Biosciences Biotechnology Research Asia  
The kinetic and mechanism of the reaction between benzaldehyde, malononitrile and dimedone has been studied in the presence agar as a highly efficient homogenous catalyst in a mixture of (water/ethanol, 2:1). Based on the experiment data, the overall order of reaction for the formation of tetrahydrobenzo[b]pyran followed second-order kinetics and under pseudo-order conditions the partial orders with respect to 1, 2 and 3 were one, one and zero, respectively. From the temperature, concentration
more » ... ure, concentration and solvent studies, the activation energy (E a ) and the related kinetic parameters (Δ Δ Δ Δ ΔG ‡ , Δ Δ Δ Δ ΔS ‡ and Δ Δ Δ Δ ΔH ‡ ) are calculated. The first step of the proposed mechanism is recognized as a rate-determining step (k 1 ) and this is proved by the steady state approximation.
doi:10.13005/bbra/2090 fatcat:6rrkh3jedrbl5dj5pgdjp2joee