eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-06-25 13 2 715 723 10.13005/bbra/2090 14167 article Mehdi Shahraki 1 Sayyed Mostafa Habibi-Khorassani 1 Sayyedeh Shadfar Pourpanah 1 Department of Chemistry, University of Sistan and Baluchestan, P.O.Box 98135-674, Zahedan, Iran. 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 and solvent studies, the activation energy (E_a) and the related kinetic parameters (ΔG^‡, ΔS^‡ and ΔH^‡) are calculated. The first step of the proposed mechanism is recognized as a rate-determining step (k₁) and this is proved by the steady state approximation. https://www.biotech-asia.org/vol13no2/kinetic-aspects-of-tetrahydrobenzobpyran-formation-in-the-presence-of-agar-as-a-green-catalyst-a-mechanistic-investigation/ Kinetics;Mechanism;Tetrahydrobenzo[b]pyran;Agar;Catalyst