Oxidation of phenol with H2O2 catalysed by Cu(II), Ni(II) and Zn(II) complexes of N,N′-bis-(salicylidene)diethylenetriamine (H2saldien) encapsulated in Y-zeolite

✍ Scribed by Mannar R. Maurya; Salam J.J. Titinchi; Shri Chand

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 207 KB
• Volume: 201
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(03)00193-6

✦ Synopsis

Interaction of excess of N,N -bis(salicylidene)diethylenetriamine (H 2 saldien) with Cu(II), Ni(II) and Zn(II) exchanged zeolite-Y at ca. 90 • C leads to the encapsulation of ligand in the super cages of zeolite followed by complexation with metal ions. These encapsulated metal complexes have been characterised by IR and UV-Vis spectroscopic studies and thermal as well as X-ray diffraction (XRD) patterns. All encapsulated complexes serve as catalyst for the decomposition of H 2 O 2 and for the oxidation of phenol to a mixture of catechol and hydroquinone using H 2 O 2 as an oxidant. A suitable reaction condition has been optimised for [Zn(saldien)]-Y by considering the effect of various parameters such as different solvents, concentration of substrate, reaction time and amount of oxidant etc. for the maximum transformation of phenol. Thus, for a fixed amount of catalyst (0.025 g), 5.67 g of 30% H 2 O 2 in 2 ml MeCN were sufficient enough to catalyse the oxidation of 4.70 g of phenol at 80 • C to give maximum transformation of phenol. Under the same reaction conditions the catalytic activity of these complexes follow the order: [Zn(saldien)]-Y (53%) > [Ni(saldien)]-Y (51%) > [Cu(saldien)]-Y (45%) after 24 h of reaction time. These catalytic activities were always found better over their respective non-encapsulated complexes.