Encapsulation of Cu(II),Ni(II) and V(IV) - imidazole complexes in fly ash zeolite,characterisation and catalytic activity towards hydroxylation of phenol

In this article,a new method for the utilization of fly ash has been proposed. x-type zeolite was prepared from fly ash by alkali fusion followed by hydrothermal method. the prepared fly ash based zeolite (faz) was characterised using ftir,xrd,tga and xrf and from bet analysis the surface area was found to be 172.83 m2/g and the pore volume was 0.014 cm3/g. cation exchange capacity (cec) of raw fly ash was found to be 0 meq/100g while that of faz was estimated to be 457 meq/100g. the increase in surface area and cec confirms zeolitisation. cu(ii),ni(ii) and v(iv) - imidazole complexes were encapsulated in faz using flexible ligand method. the faz encapsulated with complexes were characterised by ft-ir,xrd,uv-vis,aas and tga. the c=n stretching frequency observed at 1068 cm-1 and n-h stretching observed at ~3419 cm-1 clearly indicate the loading of metal-imidazole complexes in the pores of fly ash zeolite. thermo grams of the metal complexes encapsulated fly ash zeolite shows an additional weight loss at 200-500°c which confirms the loading of metal complexes in zeolite. x-ray diffraction patterns of the encapsulated metal complexes remain unaffected due to poor loading of the metal complexes in the pores of zeolite. hydroxylation of phenol has been chosen as a model reaction and the catalytic activity of the encapsulated complexes towards this reaction has been monitored as a function of time. the results reveal up to 81.8% conversion of phenol to hydroquinol which has been characterised by gc-ms.