Faculty Publications
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Item Methanol selective oxidation to formaldehyde over a modified Fe-Mo catalyst with two different stoichiometric (Mo/Fe atomic ratio = 1.5 and 3.0) was studied experimentally in a fixed bed reactor over a wide range of reaction conditions. The physicochemical characterization of the prepared catalysts provides evidence that Fe2(MoO4)3 is in fact the active phase of the catalyst. The experimental results of conversion of methanol and selectivity towards formaldehyde for various residence times were studied. The results showed that as the residence time increases the yield of formaldehyde decreases. Selectivity of formaldehyde decreases with increase in residence time. This result is attributable to subsequent oxidation of formaldehyde to carbon monoxide due to longer residence time.(Selective oxidation of methanol to formaldehyde using modified iron-molybdate catalysts) Kim, T.-H.; Badekai Ramachandra, B.; Choi, J.-S.; Saidutta, M.B.; Choo, K.-Y.; Song, S.-D.; Rhee, Y.-W.2004Item The direct conversion of benzene to phenol by hydroxylation with hydrogen peroxide was carried out over catalysts containing iron impregnated on activated carbon. Iron was impregnated on various surface modified activated carbons. The catalyst that was made by treating activated carbon with nitric acid, that was treated thermally in the presence of nitrogen at 600 °C and impregnated with 5 wt.% iron, gave a phenol yield of 20%. It was found that the synergistic interactions of surface groups and the impregnated iron have enhanced the performance of these catalysts. © 2005 Elsevier B.V. All rights reserved.(Direct synthesis of phenol from benzene on iron-impregnated activated carbon catalysts) Choi, J.-S.; Kim, T.-H.; Choo, K.-Y.; Sung, J.-S.; Saidutta, M.B.; Ryu, S.-O.; Song, S.-D.; Badekai Ramachandra, B.; Rhee, Y.-W.2005Item Molybdenum based mixed oxide containing Mo0.65V 0.25W0.10 was investigated for the partial oxidation of methanol. The structural property and catalytic activity of the mixed oxide catalyst was studied by surface area (BET), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infra-red spectroscopy (FTIR) and X-ray diffraction (XRD). The thermal activation of the catalyst resulted increase in the conversion of methanol and the selectivity to formaldehyde. The thermal activation of the MoVW mixed oxide in nitrogen atmospheres induces partial crystallization of a Mo5O14-type oxide at 813 K. The SEM images of the thermally activated catalyst show needle like particles. These particles were agglomerates of platelet-like crystallites of a few hundreds of nanometers in size. SEM and EDX techniques show that the mixed oxide is characterized by an inhomogeneous elemental distribution on the length scale of a few microns. XRD of the thermally activated catalyst showed a nanocrystalline material identified as a mixture of Mo5O 14, MoO3 and MoO2-type MoVW oxides. The catalytic activity of the MoVW mixed oxide show a good conversion of methanol and selectivity to formaldehyde. © 2005 Springer Science+Business Media, Inc.(Partial oxidation of methanol to formaldehyde on molybdenum based mixed oxide catalyst) Badekai Ramachandra, B.; Choi, J.-S.; Choo, K.-Y.; Sung, J.-S.; Song, S.-D.; Kim, T.-H.2005Item Synthesis and characterization of nanocrystalline Mo-V-W-Fe-O mixed oxide catalyst and its performance in selective methanol oxidation(2007) Badekai Ramachandra, B.; Choi, J.-S.; Kim, T.-H.A mixed oxide catalyst containing Mo, V, W and Fe with the composition of 63, 23, 09 and 06 wt% respectively for the selective oxidation of the methanol to formaldehyde is in reported in this paper for the first time. The characterization of the catalyst was done using BET surface analysis, X-ray diffraction (XRD), Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX). The mixed oxide after calcination at 673 K in N2 which was subjected for the thermal activation in N 2flow at 813 K was used for the methanol selective oxidation. The thermal treatment shows enhanced catalytic performance. Thermal activation of the nanocrystalline Mo0.63V23W0.09Fe 0.06O x precursor oxide in nitrogen atmospheres induces partial crystallization of a Mo5O14-type oxide only in a narrow temperature range up to 813 K. XRD showed that the thermally activated mixed oxide consists of a mixture of a majority of crystalline Mo 5O14-type oxide and of small amounts of crystalline MoO3-type and MoO2-type oxides. The structural analysis suggests that the improvement of the catalytic performance of the MoVWFe oxide catalyst in the selective oxidation of methanol is related to the formation of the catalytic active site such as Mo5O14-type mixed oxide. © 2007 Springer Science+Business Media, LLC.Item Green approach to synthesize multi-walled carbon nanotubes by using metal formate as catalyst precursors(2013) Rajarao, R.; Badekai Ramachandra, B.The multi-walled nanotubes (MWNTs) have been synthesized in large scale by using metal formate as catalyst precursors. The calcium carbonate is used as catalyst support, it is chosen because of its non toxic and easily soluble nature. The synthesis was carried out by chemical vapor deposition method for 15 min under optimized conditions. The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and X-ray diffraction (XRD) method. The purity of the as grown products and purified products were determined by thermal analysis. The obtained yield of MWNTs was about 8300 wt% relative to the nickel catalyst. This synthesis route avoids the lengthy process of calcination and reduction for the preparation of catalysts hence this method is more economical. This economical and environmental friendly synthesis route can be used for synthesizing MWNTs in large scale. Copyright © 2013 American Scientific Publishers All rights reserved.