T. Peter Amaladhas; S. Sheeba Thavamani
Abstract
A new route for the utilization of fly ash has been formulated. X-type zeolite has been synthesized from fly ash by alkali fusion followed by hydrothermal treatment. Ascorbic acid was used as a ligand for the synthesis of metal complexes of copper, nickel and vanadium encapsulated in the super cages ...
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A new route for the utilization of fly ash has been formulated. X-type zeolite has been synthesized from fly ash by alkali fusion followed by hydrothermal treatment. Ascorbic acid was used as a ligand for the synthesis of metal complexes of copper, nickel and vanadium encapsulated in the super cages of fly ash based zeolite (FAZ) by flexible ligand method and characterized by FTIR, XRD, Atomic Absorption Spectrometry (AAS), Ultra Violet–Visible spectroscopy and Thermo gravimetric analysis (TGA). The additional peaks corresponding to that of the complex have been observed which confirms the loading of the metal complexes in the zeolite cavities. The shifting of C=C-O stretching frequency found at 682 cm -1 in ascorbic acid to 601 cm -1 confirms the co-ordination of the ligand resulting in the formation of the metal complex. The thermo grams show deflation in three regions corresponding to the loss of the intra-zeolite water, metal complexes and the structural –OH group respectively. The catalytic activity of these complexes towards the liquid phase hydroxylation of phenol with hydrogen peroxide has been established. The extent of the reaction as a function of time has been investigated. Vanadium-ascorbate complex had the highest conversion of 78%. The product was identified as hydroquinol by GC-MS. This study reports a highly attractive catalytic method for the preparation of hydroquinol from phenol using aqueous hydrogen peroxide as the oxidising agent which is industrially significant.
T. Peter Amaladhas; S. Sheeba Thavamani
Abstract
Coal fly ash has been used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. The synthesized fly ash based zeolite (FAZ) has been characterized by various analytical techniques. Copper(II), Nickel(II) and Zinc(II) complexes of N,N 1 -ethylenebis (salicylamide) encapsulated ...
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Coal fly ash has been used to synthesize X-type zeolite by alkali fusion followed by hydrothermal treatment. The synthesized fly ash based zeolite (FAZ) has been characterized by various analytical techniques. Copper(II), Nickel(II) and Zinc(II) complexes of N,N 1 -ethylenebis (salicylamide) encapsulated in the supercages of FAZ have been prepared by flexible ligand method and characterized by Fourier Transform infra red spectroscopy (FTIR), X-ray diffraction (XRD) analysis, Scanning electron microscopy (SEM), Atomic absorption spectrometry (AAS), Ultra Violet – Visible spectroscopy and Thermo gravimetric analysis (TGA). These complexes have been found to catalyze the liquid phase hydroxylation of phenol with hydrogen peroxide to yield catechol. It appears to be the first report of catalysis of metal complex encapsulated in fly ash based zeolite.
Chetan K. Modi; Parthiv M. Trivedi
Abstract
Zeolites encumbered with transition metal ions are promising heterogeneous catalysts. Knowledge about the location and structure of the metal centers is of paramount importance for the understanding of the catalytic potential of these materials. A series of entrapped transition metal complexes in the ...
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Zeolites encumbered with transition metal ions are promising heterogeneous catalysts. Knowledge about the location and structure of the metal centers is of paramount importance for the understanding of the catalytic potential of these materials. A series of entrapped transition metal complexes in the nanopores of zeolite-Y of the type [M(EVTCH)2]-Y [where M = Mn(II), Co(II), Ni(II) and Cu(II); ethylvanillin thiophene-2-carboxylic hydrazone (EVTCH)] have been synthesized by Flexible Ligand Method (FLM). These materials have been characterized by various physico-chemical techniques such as ICP-OES, GC-MS, elemental analyses, (FT-IR, 1H- and 13C-NMR and electronic) spectral studies, BET, scanning electron micrographs (SEMs) as well as X-ray diffraction patterns (XRD). The catalytic significance of these materials has been carried out over the liquid-phase hydroxylation of phenol with 30 % H2O2 to give catechol as a major product and hydroquinone as a minor product.
