@conference { ISI:000230895600102, title = {Immobilized molybdovanadophosphoric acids on SBA-15 for selective oxidation of alkenes}, booktitle = {4th International Symposium on Nanoporous Materials}, series = {STUDIES IN SURFACE SCIENCE AND CATALYSIS}, volume = {156}, year = {2005}, note = {4th International Symposium on Nanoporous Materials, Niagara Falls, CANADA, JUN 07-10, 2005}, month = {JUN}, pages = {769-778}, publisher = {Elsevier Science BV, Sara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, Netherlands}, organization = {Elsevier Science BV, Sara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, Netherlands}, address = { Niagara Falls, Canada}, abstract = {

Vanadium substituted molybdophosphoric acids have been immobilized on amine functionalized SBA-15 and characterized by different techniques. Small angle X-ray scattering analysis and SEM technique provide evidence for the structural integrity of the samples. UV-Vis, NMR and IR data confirm the incorporation of molybdovanadophosphoric acids onto the amine functionalized SBA-15. The textural properties of these materials were studied by nitrogen sorption studies. Oxidation of cyclooctene and norbornene was carried out with oxidants in aqueous (aq. H2O2) and non-aqueous (TBHP extracted in dichloroethane) medium. The reactions were carried out with both the neat catalysts (homogeneous) and the immobilized catalysts (heterogenized) and the results were compared. The selectivity of the desired products was always \> 99\% with the immobilized catalyst with both aq.H2O2 and TBHP. However, while the leaching was negligible in the non-aqueous medium, the aqueous medium leads to considerable leaching. The immobilized catalysts could be separated after the reaction and the reusability of the catalyst has also been demonstrated especially with oxidant in the nonaqueous medium.

}, isbn = {0-444-51748-0}, issn = {0167-2991}, author = {Raj, N. K. K. and Deshpande, S. S. and Ingle, Rohit H. and Raja, T. and Manikandan, Palanichamy}, editor = {Sayari, A. and Jaroniec, M.} } @article { ISI:000226424000005, title = {Oxidation of norbornene over vanadium-substituted phosphomolybdic acid catalysts and spectroscopic investigations}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {227}, number = {1-2}, year = {2005}, month = {MAR}, pages = {37-45}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Oxidation of norbornene has been carried out over mono-, di- and tri-vanadium-substituted phosphomolybdic acid catalysts with aqueous hydrogen peroxide (aq. H2O2) as an oxidant in different solvents. Monovanadium-substituted phosphomolybdic acid catalyst was found to be better than other catalysts for the above reaction and acetonitrile was the suitable solvent. At the optimum temperature of 60 degreesC, the norbornene conversion was 70\% and the selectivity for 2,3-epoxy norbornane was 58\%. The side products were norborneols and 2-norbornanone. The lower selectivity of 2,3-epoxy norbornane with aq. H2O2 is attributed to the simultaneous formation of other products, norborneols and 2-norbornanone. The norborneols are formed from norbornene by acid-catalyzed reaction. Other oxidants like urea-hydrogen peroxide adduct (UHP) and tert-butyl hydrogen peroxide (TBHP) were also tested for norbornene oxidation reaction. With UHP, the conversion was almost same (69\%) as that of aq. H2O2 reaction; however, 2,3-epoxy norbornane was the main product with \>97\% selectivity. Thus, the overall yield was 66.9\% at 60 degreesC after 4 h. The high selectivity with UHP is attributed to the controlled release of H2O2, absence of water and less acidic nature of UHP. With TBHP the selectivity for the epoxide was \>96\%; however, the conversion was low (27\%). A mechanism for the norbornene oxidation is believed to be proceeding via V(5+)-peroxo and V(4+)-superoxo intermediates. NMR, EPR and UV-vis spectroscopic techniques were employed to understand the reaction intermediates and reaction pathways. (C) 2004 Elsevier B.V. All rights reserved.

}, keywords = {2, 3-epoxy norbornane, aq. H2O2, epoxidation, EPR, NMR, norbornene, urea-H2O2 adduct, UV-Vis, vanadium-substituted phosphomolybdic acid}, issn = {1381-1169}, doi = {10.1016/j.molcata.2004.10.005}, author = {Raj, N. K. K. and Ramaswamy, A. and Manikandan, Palanichamy} } @article { ISI:000228779100008, title = {Synthesis, characterization and catalytic potentials of polymer anchored copper(II), oxovanadium(IV) and dioxomolybdenum(VI) complexes of 2-(alpha-hydroxymethyl)benzimidazole}, journal = {Reactive \& Functional Polymers}, volume = {63}, number = {1}, year = {2005}, month = {MAR}, pages = {71-83}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

{2-(alpha-Hydroxymethyl)benzimidazole (Hhmbmz) has been covalently anchored to chloromethylated polystyrene cross-linked with 5\% divinylbenzene. This chelating resin reacts with cupric acetate, vanadyl sulphate and [MoO(2)-(acac)(2)] (Hacac = acetylacetone) in presence of Hhmbmz to give complexes PS-[Cu(hmbmz)(2)], PS-[VO(hmbmz)(2)] and PS-[MoO(2)(hmbmz)(2)] (where

}, keywords = {2-(alpha-hydroxymethyl)benzimidazole, oxidation of styrene and ethyl benzene, oxidative bromination of salicylaldehyde, polymer anchored-complexes}, issn = {1381-5148}, doi = {10.1016/j.reactfunctpolym.2005.02.008}, author = {Maurya, Mannar R. and Sikarwar, S. and Joseph, Trissa and Manikandan, Palanichamy and Halligudi, Shivappa B.} } @article { ISI:000242775600009, title = {Oxovanadium(IV) complex of 2-(alpha-hydroxyethyl)benzimidazole covalently bonded to chloromethylated polystyrene for oxidation of benzoin}, journal = {Applied Catalysis A-General}, volume = {315}, year = {2006}, month = {NOV}, pages = {74-82}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Vanadyl sulphate reacts with 2-(alpha-hydroxyethyl)benzimidazole covalently bonded to chloromethylated polystyrene (PS-Hhebmz) cross-linked with 5\% divinyl benzene to give PS-[VO(hebmZ)(2)]. Characterisation of the catalyst was carried out by IR, electronic and EPR spectroscopic studies, thermogravimetry, scanning electron micrographs and elemental analyses. Catalytic potential of the complex was tested for the oxidation of benzoin using tert-butyl hydroperoxide (TBHP) as an oxidant in methanol where benzil, methylbenzoate, benzoic acid and dimethylacetal were obtained as products. Various parameters such as different solvents and concentration of the substrate as well as oxidant have been taken into consideration for the maximum oxidation of the benzoin. Under optimised reaction conditions, a maximum of 98.9\% conversion of the benzoin was achieved after 6 h of reaction time where selectivity of the obtained reaction products varied in the order: methylbenzoate (48.5\%) \> benzil (19.5\%) \> dimethylacetal (17.1\%) \> benzoic acid (11.5\%). Neat complex was also prepared to compare its catalytic property with polymer-anchored one. EPR spectra of neat and polymer anchored catalyst are characteristics of V(IV) complexes with typical axial pattern and possible square pyramidal geometry. The identical EPR spectral patterns of both freshly prepared and recovered anchored catalysts indicate that the complex is stable and the coordination environment is retained at the end of the catalytic reaction. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {2-(alpha-hydroxyethyl)benzimidazole, oxidation of benzoin, polymer-anchored complex, Polystyrene, vanadium(IV) complex}, issn = {0926-860X}, doi = {10.1016/j.apcata.2006.09.003}, author = {Maurya, Mannar R. and Sikarwar, Sweta and Manikandan, Palanichamy} } @article {KULKARNI, title = {Polymer supported vanadium and molybdenum complexes as potential catalysts for the oxidation and oxidative bromination of organic substrates}, journal = {Dalton Transactions}, number = {29}, year = {2006}, note = {Conference on Atomic Molecular and Optical Physics, Calcutta, INDIA, DEC 13-15, 2005}, month = {APR}, pages = {3561-3575}, publisher = {Indian Assoc Cultivat Sci}, type = {Review}, address = {PO BOX 128 FARRER RD, SINGAPORE 9128, SINGAPORE}, abstract = {

{The Schiff base (H(2)fsal-ohyba) derived from 3-formylsalicylic acid and o-hydroxybenzylamine has been covalently bonded to chloromethylated polystyrene cross-linked with 5\% divinylbenzene ( abbreviated as PS-H(2)fsal-ohyba, I). Treatment of [

}, keywords = {Bile acids, bis-steroids, hybrids, Peptides, polyamines, saponins, steroidal conjugates, synthetic ionophores}, doi = {10.1039/b600822d}, author = {Maurya, Mannar R. and Kumar, Umesh and Manikandan, Palanichamy} } @article { ISI:000240639000014, title = {Transesterification of cyclic carbonates with methanol at ambient conditions over tungstate-based solid catalysts}, journal = {Applied Catalysis A-General}, volume = {312}, year = {2006}, month = {SEP}, pages = {108-114}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Dimethyl carbonate synthesis with 80 mol\% yield is achieved through transesterification of ethylene carbonate with methanol at ambient conditions (RT and atmospheric pressure) using alkali and alkaline-earth tungstates as solid catalysts. The catalysts are efficient even at the sub-ambient temperatures. Reactions under CO2 pressure indicate that CO2 atmosphere retards the transesterification reaction completely below 100 degrees C. Experimental conditions of 150 degrees C and 3.4 MPa CO2 pressure are required to obtain maximum DMC yield of 71 mol\%. Synthesis of DMC by one-pot synthesis using epoxide, CO2 and methanol is not as effective as that by two-step method with the present catalyst system. Raman and IR spectra of methanol-interacting tungstates indicate the formation of a methoxide ion species adsorbed at the catalyst surface as one possible reaction intermediates. (C) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Dimethyl carbonate, ethylene carbonate, heterogeneous catalyst, Raman spectroscopy, sodium tungstate, transesterification}, issn = {0926-860X}, doi = {10.1016/j.apcata.2006.06.034}, author = {Sankar, M. and Nair, C. Madhavan and Murty, K. V. G. K. and Manikandan, Palanichamy} } @article { ISI:000244183400009, title = {[SbW9O33]-based polyoxometalate combined with a phase transfer catalyst: A highly effective catalyst system for selective oxidation of alcohols with H2O2, and spectroscopic investigation}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {262}, number = {1-2}, year = {2007}, month = {FEB}, pages = {52-58}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Na-9[SbW9O33] in conjunction with a phase transfer catalyst, methyltricapryl ammonium chloride, is highly efficient for selective oxidation of variety of alcohols with aq. H2O2 to yield corresponding carbonyls. Most importantly the reactions are carried out in the absence of any organic solvents especially halogenated solvents. In case of allylic alcohols, the catalyst is highly selective for the alcohol oxidation reaction and least selective for epoxidation reaction in the presence of aq. H2O2. IR studies support the formation of W-peroxo intermediate species and also support the stability of the catalyst in the presence of phase transfer compound under the present experimental condition. The catalyst can be reused after careful decomposition of peroxide of the final reaction mixture. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Alcohol, Aq.H2O2, Nag[SbW9O33], Oxidation, Phase transfer catalyst, Polyoxometalate, polyoxotungstate}, issn = {1381-1169}, doi = {10.1016/j.molcata.2006.08.050}, author = {Ingle, Rohit H. and Raj, N. K. Kala and Manikandan, Palanichamy} } @article {Bhattacharya, title = {Synthesis and characterisation of polymer-anchored oxidovanadium(IV) complexes and their use for the oxidation of styrene and cumene}, journal = {European Journal of Inorganic Chemistry}, number = {16}, year = {2007}, month = {JUN}, pages = {2303-2314}, publisher = {SPRINGER}, type = {Article}, address = {233 SPRING STREET, NEW YORK, NY 10013 USA}, abstract = {

{The Schiff bases H(2)fsal-ea (I), H(2)fsal-pa (II) and H(2)fsal-amp (III), derived from 3-formylsalicylic acid and 2-aminoethanol, 3-aminopropanol and 2-amino-2-methylpropanol, respectively, have been connected, by means of covalent bonds, to chloromethylated polystyrene cross-linked with 5\% divinylbenzene. On treatment with [

}, keywords = {dissolution rate, mass transfer coefficient, particle size distribution, polydisperse solid, reactive liquid}, issn = {0930-7575}, author = {Maurya, Mannar R. and Kumar, Umesh and Manikandan, Palanichamy} } @article { ISI:000252563300006, title = {Selective oxidation of ethane over Mo-V-Al-O oxide catalysts: insight to the factors affecting the selectivity of ethylene and acetic acid and structure-activity correlation studies}, journal = {Catalysis Letters}, volume = {121}, number = {1-2}, year = {2008}, month = {FEB}, pages = {39-51}, publisher = {SPRINGER}, address = {233 SPRING STREET, NEW YORK, NY 10013 USA}, abstract = {

Catalysts of general formula, MoVAlOx were prepared with the initial elemental composition of 1:0.34:0.167 (Mo:V:Al) at a pH value in the range of 1-4. The elemental analysis showed that the final composition of the catalysts is pH dependant. The performance of the catalysts was tested for selective oxidation of ethane to give ethylene and acetic acid. While all of them were active for ethane oxidation with a moderate conversion, the catalyst prepared at pH 2 showed a highest activity with 23\% ethane conversion and a combined selectivity of 80.6\% to ethylene and acetic acid. The catalyst prepared at pH 4 was least selective to ethylene and acetic acid. Various techniques like powder XRD, SEM, Raman, UV-Vis and EPR were used to characterize the catalysts and to identify the active phases responsible for the selective oxidation of ethane. The powder XRD data showed that the catalysts prepared at pH 1 and 2 contain mainly of MoO3 and MoV2O8 along with traces of Mo4O11. The amount of MoO3 was slightly higher in the catalyst prepared at pH 1. However, the catalyst prepared at pH 3 contains mainly of MoV2O8 with no trace of MoO3. The catalyst prepared at pH 4 showed V2O5 as the major phase along with MoVAlO4 phase. The Raman data corroborated the XRD results. EPR and UV-Vis studies indicated the presence of traces of V-4 in pH 1 and 2 catalysts and significant amount of Mo5+ in all the catalysts. Thus, the high activity and selectivity to ethylene and acetic acid are attributed to the presence of MoV2O8 phase and other reduced species like Mo4O11 phase supported on MoO3. The presence of V and Mo ions in a partially reduced form seems to play a crucial role in the selective oxidation of ethane.

}, keywords = {Acetic acid, ethane, Ethylene, mixed metal oxide, Selective oxidation}, issn = {1011-372X}, doi = {10.1007/s10562-007-9289-0}, author = {Sankaranarayanan, T. M. and Ingle, Rohit H. and Gaikwad, T. B. and Lokhande, S. K. and Raja, T. and Devi, R. N. and Ramaswamy, V. and Manikandan, Palanichamy} } @article { ISI:000272560400015, title = {Immobilization of phosphotungstic acid (PTA) on imidazole functionalized silica: evidence for the nature of PTA binding by solid state NMR and reaction studies}, journal = {Journal of Physical Chemistry C}, volume = {113}, number = {50}, year = {2009}, month = {DEC}, pages = {21114-21122}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Phosphotungstic acid (PTA) immobilized onto imidazole functionalized fumed silica and was used its an efficient catalyst for epoxidation of a variety of olefins using aqueous H(2)O(2) as all oxidant. Negligible leaching of PTA under the reaction conditions employed indicates a strong interaction between PTA and imidazole The immobilized catalysts Could be separated and reused after the catalytic cycle Evidence for the heterogenization of PTA oil the imidazole functionalized fumed silica has been inferred from different spectroscopic techniques like IR, UV-vis, and NMR. Importantly, the nature of binding of PTA oil the support has been studied in detail by solid state NMR spectroscopy using (15)N labeled imidazole Support. It is clear from the NMR Studies that the effective heterogenization of PTA is mainly due to imidazolium ion Formation oil the support by the acidic protons of PTA and the resultant ion pair

}, issn = {1932-7447}, doi = {10.1021/jp906108e}, author = {Sofia, L. T. Aany and Krishnan, Asha and Sankar, M. and Raj, N. K. Kala and Manikandan, Palanichamy and Rajamohanan, P. R. and Ajithkumar, Thalasseril G.} } @article { ISI:000278725100017, title = {Transesterification of cyclic carbonates to dimethyl carbonate using solid oxide catalyst at ambient conditions: environmentally benign synthesis}, journal = {Chemsuschem}, volume = {3}, number = {5}, year = {2010}, month = {MAY}, pages = {575-578}, publisher = {WILEY-V C H VERLAG GMBH}, address = {PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY}, keywords = {calcium, environmental chemistry, heterogeneous catalysis, transesterification zinc}, issn = {1864-5631}, doi = {10.1002/cssc.201000038}, author = {Sankar, Meenakshisundaram and Satav, Srikanth and Manikandan, Palanichamy} } @article {45886, title = {Supported imidazole as heterogeneous catalyst for the synthesis of cyclic carbonates from epoxides and CO2}, journal = {Catalysis Communications}, volume = {59}, year = {2015}, month = {JAN }, pages = {201-205}, type = {Article}, abstract = {

Imidazole anchored onto a silica matrix, by means of a propyl linkage, is found to be an effective heterogeneous catalyst for the synthesis of cyclic carbonates from epoxides and CO2 in near quantitative yield. The versatility of this catalyst is demonstrated by using different substrates (epichlorohydrin, propylene oxide, butylene oxide and styrene oxide) for this cycloaddition reaction. These CO2 insertion reactions were typically carried out in the temperature range of 343 to 403 K at 0.6 MPa CO2 pressure under solvent-free conditions. Several spectroscopic methods were used to characterize the catalyst and study the integrity of the fresh and spent catalysts. (C) 2014 Elsevier B.V. All rights reserved.

}, keywords = {Anchored imidazole, CO2 utilization, cyclic carbonates, epoxides}, issn = {1566-7367}, doi = {10.1016/j.catcom.2014.10.026}, author = {Sankar, Meenakshisundaram and Ajithkumar, Thalasseril G. and Sankar, Gopinathan and Manikandan, Palanichamy} }