@article { ISI:000229488700008, title = {Vapor phase oxidation of 4-fluorotoluene over vanadia-titania catalyst}, journal = {Journal of Molecular Catalysis A - Chemical}, volume = {234}, number = {1-2}, year = {2005}, month = {JUN}, pages = {51-57}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The vapor phase oxidation of 4-fluorotoluene has been carried out over vanadia-titania catalysts with moderate conversion and selectivity for 4-fluorobenzaldehyde. Two series of V2O5/TiO2 catalysts with 1-10 mol\% vanadia were prepared by sol-gel technique using vanadium and titanium peroxide as vanadia and titania precursors respectively and by impregnation technique using vanadium peroxide on anatase titania support. The samples were characterized by X-ray diffraction, NH3-TPD, FT-IR and BET surface area measurements. The XRD of the catalysts prepared by impregnation technique showed retention of the anatase titania whereas the catalysts prepared by sol-gel technique showed the formation of rutile titania with minor amount of anatase phase at lower vanadia content (1-3 \%), which completely transformed into anatase phase at higher vanadia loading. The samples prepared by sol-gel method showed higher acidity and surface area compared to the samples prepared by impregnation. Pyridine adsorption study by FT-IR revealed the presence of Lewis acidity at lower vanadia loading (1-3 \%) and presence of both Lewis as well as Bronsted acidity at higher vanadia loading. The catalytic activity for oxidation of 4-fluorotoluene increased with vanadia loading in the sol-gel catalysts. The catalysts prepared by impregnation technique were found to be less active. However the selectivity for 4-fluorobenzaldehyde decreased with increase in vanadia content. The influence of vanadia loading, reaction temperature and contact time on the catalytic activity for 4-fluorotoluene oxidation has been investigated. The structure of the catalyst and its catalytic activity has been correlated. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {Catalyst, fluorotoluene, Oxidation, vanadia-titania, vapor phase}, issn = {1381-1169}, doi = {10.1016/j.molcata.2005.02.020}, author = {Maurya, S. K. and Patil, P. and Shubhangi B. Umbarkar and Gurjar, M. K. and Dongare, Mohan K. and Rudiger, S. and Kemnitz, E.} } @article { ISI:000250026200021, title = {Synthesis of tinidazole by condensation-oxidation sequence using MoO3/SiO2 bifunctional catalyst}, journal = {Catalysis Communications}, volume = {8}, number = {10}, year = {2007}, month = {OCT}, pages = {1550-1555}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Antimicrobial drug, tinidazole has been synthesized by condensation of 2-methyl,5-nitro-imidazole and 2-ethyl-thio-ethanol over MoO3/SiO2 catalyst to obtain 1-(2-ethyl-thio-ethanol)-2-methyl-5-nitro-imidazole which is further oxidized using hydrogen peroxide using the same MoO3/SiO2 catalyst to obtain tinidazole. MoO3/SiO2 catalyst (20\%), synthesized by sol-gel process showed the highest acid strength and was successfully demonstrated to catalyze both condensation and oxidation in the synthesis of tinidazole. Due to the bifunctional activity of the catalyst, the use of acetic acid for condensation step and tungstic acid or ammonium molybdate for oxidation step in the conventional synthesis of tinidazole could be eliminated, thus making it an environmentally benign process. The catalysts could be recycled five times without any appreciable loss in the conversion and selectivity showing the potential for. the use of MoO3/SiO2 as bifunctional catalyst for the production of this industrially important compound. (C) 2007 Elsevier B.V. All rights reserved.

}, keywords = {antimicrobial drug, condensation, MoO3/SiO2, Oxidation, solid acid catalyst, tinidazole}, issn = {1566-7367}, doi = {10.1016/j.catcom.2007.01.001}, author = {Chandorkar, J. G. and Shubhangi B. Umbarkar and Rode, C. V. and Kotwal, V. B. and Dongare, Mohan K.} } @article { ISI:000256043100018, title = {Selective N-oxidation of aromatic amines to nitroso derivatives using a molybdenum acetylide oxo-peroxo complex as catalyst}, journal = {Tetrahedron Letters}, volume = {49}, number = {22}, year = {2008}, month = {MAY}, pages = {3616-3619}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

The molybdenum acetylide oxo-peroxo complex obtained in situ by the treatment of the corresponding molybdenum acetylide carbonyl complex, CpMo(CO)(3)(C CPh); Cp = eta(5-)C(5)H(5) with H(2)O(2), has been used as an efficient catalyst for selective N-oxidation of primary amines to nitroso derivatives. Excellent amine conversion (up to 100\%) and very high selectivity for nitroso compounds (99\%) have been obtained using 30\% hydrogen peroxide as an oxidant. The oxo peroxo, Mo(VI) complex has also been found to be very active for the oxidation of various substituted primary aromatic amines with electron donating as well as electron withdrawing substituents on the aromatic ring. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {aromatic amine, Homogenous catalyst, Hydrogen peroxide, Molybdenum complex, nitroso, Oxidation, Oxo-peroxo}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2008.04.005}, author = {Biradar, Ankush V. and Kotbagi, Trupti V. and Dongare, Mohan K. and Shubhangi B. Umbarkar} } @article { ISI:000266188300010, title = {Selective oxidation of aromatic primary alcohols to aldehydes using molybdenum acetylide oxo-peroxo complex as catalyst}, journal = {Tetrahedron Letters}, volume = {50}, number = {24}, year = {2009}, month = {JUN}, pages = {2885-2888}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Selective oxidation of various aromatic alcohols to aldehydes has been carried out with very high conversion (90\%) and selectivity (90\%) for aldehydes using cyclopentadienyl molybdenum acetylide complex, CpMo(CO)(3)(C CPh) (1) as catalyst and hydrogen peroxide as environmentally benign oxidant, Water-soluble Mo acetylide oxo-peroxo species is formed in situ after reaction of I with aqueous hydrogen peroxide during the Course of reaction as catalytically active species. Interestingly even though the catalyst is homogeneous it Could be recycled very easily by separating the products in organic phase and catalyst in aqueous phase using separating funnel. Even after five recycles no appreciable loss in alcohol conversion and aldehyde selectivity was observed. (C) 2009 Elsevier Ltd. All rights reserved.

}, keywords = {Homogenous catalyst, Hydrogen peroxide, Molybdenum complex, Oxidation, Oxo-peroxo, Primary aromatic alcohol}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2009.03.178}, author = {Biradar, Ankush V. and Dongare, Mohan K. and Shubhangi B. Umbarkar} } @article { ISI:000307308000020, title = {Transesterification of diethyl oxalate with phenol over sol-gel MoO3/TiO2 catalysts}, journal = {Chemsuschem}, volume = {5}, number = {8}, year = {2012}, month = {JUL}, pages = {1467-1473}, publisher = {WILEY-V C H VERLAG GMBH}, type = {Article}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

The transesterification of diethyl oxalate (DEO) with phenol to form diphenyl oxalate (DPO) has been carried out in the liquid phase over very efficient MoO3/TiO2 solid-acid solgel catalysts. A selectivity of 100?\% with a remarkable maximum yield of 88?\% were obtained, which opens the route to downstream phosgene-free processes for the synthesis of polycarbonates. Interpretation of the results of various acidity measurements (NH3 and pyridine desorption, methanol oxidation as a probe reaction) allowed us to identify the catalytic sites as Lewis acid sites.

}, keywords = {heterogeneous catalysis, Lewis acids, Oxidation, sol-gel processes, transesterification}, issn = {1864-5631}, doi = {10.1002/cssc.201100802}, author = {Kotbagi, Trupti and Duy Luan Nguyen and Lancelot, Christine and Lamonier, Carole and Thavornprasert, Kaew-Arpha and Zhu Wenli and Capron, Mickael and Jalowiecki-Duhamel, Louise and Shubhangi B. Umbarkar and Dongare, Mohan K. and Dumeignil, Franck} } @article { ISI:000344470100036, title = {Molybdenum(VI) dioxo complexes for the epoxidation of allylic alcohols and olefins}, journal = {Journal of Organometallic Chemistry}, volume = {772}, year = {2014}, month = {DEC}, pages = {271-279}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

Several molybdenum(VI) dioxo complexes have been investigated as catalyst precursors for allylic alcohol epoxidation using mainly hydrogen peroxide as oxidant. All catalysts proved to be efficient and selective for the epoxidation of allylic alcohols provided the olefins were rather electron rich. Indeed, electron poor substrates could be converted selectively into the corresponding unsaturated aldehydes. A chiral dioxomolybdenum complex based on an optically pure tridentate Schiff base ligand was synthesized and characterized. Though that complex provided an efficient epoxidation catalyst for allylic alcohols and olefins, no chiral induction was observed. During the X-ray diffraction analysis, the cooling at 100 K led to the appearance of super-lattice reflections on diffraction patterns reflecting an ordering of the structure. Instead of one organometallic species observed at 298 K, three similar complexes of the same molecular structure could be observed in the asymmetric unit at 100 K. (C) 2014 Elsevier B.V. All rights reserved.

}, keywords = {Allylic alcohol, epoxidation, Molybdenum, Oxidation, Peroxide}, issn = {0022-328X}, doi = {10.1016/j.jorganchem.2014.09.029}, author = {Pandhare, Swati L. and Jadhao, Rajesh R. and Puranik, Vedavati G. and Joshi, Pranaya V. and Capet, Frederic and Dongare, Mohan K. and Shubhangi B. Umbarkar and Michon, Christophe and Agbossou-Niedercorn, Francine} }