Simulation Study of Photocatalytic Decolorization of Bismarck Brown R Using Different Quantum Calculation Methods

Author(s): Mohamed H. Obies, Abbas A-Ali Drea and Falah H. Hussein

Simulation study of photocatalytic decolorization of bismarck brown- R, (4-[5-C 2, 4-diamino-5- methylphenyl) diazenyl-2-methylphenyl] diazenyl-6-methylbenzene-1, 3-diamine dihydrochloride has been carried out using quantum calculation methods (semiemprical and Ab in tio). Reactivity of bismarck brown-R molecule has been determined using potential energy stability compares between the mean bonds. Optimizing of probable structures of chemical species have been calculated using PM3 configuration interaction microstate (4 X 4). Thirty six transition states have been postulated and studied in order to estimate the real initiation step of photocatalytic decolorization reaction for different probable path ways. Results show that hydroxyl radical can react with bismarck brown-R molecule through different active site (C7—N8, C12—N16, N16-N17 and N17—C18 bond) with lowest activation energy than other probable sites. The most probable transition states are investigated for all supposed pathways of photocatalytic decolorization Bismarck brown- R depending on energy barrier value of reaction, zero point energy and imaginary frequency for each one. The first initiation step mechanism of reaction is suggested for the path way at different conditions.

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