Kinetic Investigation of the Synthesis Reaction of 2-Phenyl-1H-Benzo[D]Imidazole Catalyzed by Xylose

Marjan Hashemi-Shahri, Sayyed Mostafa Habibi-Khorassani*, Mehdi Shahraki

Department of Chemistry, Faculty of Science, University of Sistan and Baluchestan, P. O. Box 98135-674, Zahedan, Iran

DOI : http://dx.doi.org/10.13005/bbra/1994

ABSTRACT: For the first time, xylose has been used as green and biodegradable catalyst for the synthesis of 2-phenyl-1H-benzo[d]imidazole derivatives using 1, 2-phenylenediamine and arylaldehydes in H₂O under thermal condition. This procedure has many advantages such as easy work-up, inexpensive materials, use of non-toxic catalyst and eco-friendly conditions. To specify the kinetic parameters of the reaction, it was monitored by the UV spectrophotometry method. Based on the experiment data, the order of reaction with respect to each reactant (1 and 2) is 1, 1 and overall order of the reaction is two. The reaction was followed at different temperatures and the correlate of overall rate constant (Ln k_ove) and (Ln k_ove/T) on reciprocal temperature was in a good agreement with Arrhenius and Eyring equations, respectively. This provided (data) the suitable plots for calculate the activation energy (Ea) and parameters(ΔS^‡, ΔH^‡, ΔG^‡). In addition, useful information was obtained regarding mechanism of reaction from studying the effect of solvent, concentration and catalyst. The proposed mechanism was confirmed according to the obtained results and the steady state approximation and the first and second steps (k₁, k₂) of the reactions were recognized as  the  rate determining steps.

KEYWORDS: Kinetics; Mechanism; Catalyst; Xylose

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