Oxidation of Polyphenol Trihydroxybenzene Using Environment Friendly Catalyst Copper (II) Complex of 4-Methoxyphenyl Benzopyran
Ahmed I. Hanafy*1, Ali M. Hassan1, Naglaa M. Abd El-Rahman2 and Mohamed M. M. Al-Sayed1
*Chemistry Department, Faculty of Science, Taif University, Taif, Saudi Arabia
1 Chemistry Department Faculty of Science Al-Azhar University, Cairo Egypt
2 Department of Green Chemistry, National Research Centre, Dokki, Cairo, Egypt
Abstract: The copper (II) of complex 4-methoxyphenyl benzopyran has been synthesized using microwave irradiation and characterized by different tools such as IR, electronic spectroscopy, elemental analysis, thermal analysis, and ESR spectroscopy. The mode of metal binding shows that the copper binds with the ligand through the nitrogen atoms of the amino and cyanide groups. The copper complex[Cu L (AC)2.2H2O] has been used in the homogenous oxidation of polyphenol 1,2,3-trihydroxybenzene in presence of H2O2 as a green oxidant to produce a first-order rate constant kcat = 3.45× 10-3s-1 and dissociation constant K′ = 32.0 mM. The catalysis shows 1.4× 103 times rate enhancement in terms of the first-order rate constant compared to the uncatalyzed reaction under the same reaction conditions. The oxidation reaction is inhibited by kojic acid with IC50 = 220 µM.
[Ahmed I. Hanafy, Ali M. Hassan, Naglaa M. Abd El-Rahman and Mohamed M. M. Al-Sayed. Oxidation of Polyphenol Trihydroxybenzene Using Environment Friendly Catalyst Copper (II) Complex of 4-Methoxyphenyl Benzopyran. J Am Sci 2012;8(10):22-27]. (ISSN:1545-1003)http://www.jofamericanscience.org. 5
Key words; Benzopyran derivative; microwave; oxidation; trihydroxybenzene; inhibition