@article { ISI:000242960400016, title = {Rate enhancement in palladium catalyzed Heck reactions by Lewis acid promoters}, journal = {Catalysis Communications}, volume = {8}, number = {2}, year = {2007}, month = {FEB}, pages = {183-186}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Significant enhancement in the rate of Heck reactions has been achieved when catalytic amounts of Lewis acid (like FeCl(3)) promoters in the presence of trace amounts of water (\> 2000 ppm) are used along with Pd complex catalysts. Experiments with different aryl halides, bases as well as olefins have been carried out to demonstrate the role of Lewis acid promoters. The increase in the reaction rates is due to the weakening of Ar-X bond by the Lewis acid in the manner similar to Friedel-Crafts reaction. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {Heck reaction, Lewis acid, Palladium, Promoters}, issn = {1566-7367}, doi = {10.1016/j.catcom.2006.05.043}, author = {Sud, Abhishek and Deshpande, Raj Madhukar and Chaudhari, Raghunath V.} } @article { ISI:000253382100048, title = {PdCl2(bipy) complex - an efficient catalyst for Heck reaction in glycol-organic biphasic medium}, journal = {Catalysis Today}, volume = {131}, number = {1-4}, year = {2008}, note = {4th Asia-Pacific Congress on Catalysis, Nanyang Technol Univ, Singapore, SINGAPORE, DEC 06-08, 2006}, month = {FEB}, pages = {353-359}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The Palladium complex PdCl2(bipy) (1) was found to be efficient in catalyzing the Heck reaction of aryl halides in a biphasic system comprising ethylene glycol along with an organic solvent. A proper tailoring of the organic phase ensured that the leaching of the catalyst to the organic phase was negligible. The catalyst was active for the Heck reaction of a number of olefins, aryl halides, in presence of organic and inorganic bases. The PdCl2(bipy) catalyst was stable and could be recycled for five times without any loss in activity and selectivity. A major advantage of this work is that unlike hitherto reported biphasic systems; it does not employ a water-soluble ligand to achieve biphasic catalysis. (c) 2007 Elsevier B.V. All rights reserved.

}, keywords = {Biphasic catalysis, C-C coupling, Heck reaction, PdCl2(bipy) complex}, issn = {0920-5861}, doi = {10.1016/j.cattod.2007.10.043}, author = {Jagtap, Sangeeta Vijay and Deshpande, Raj Madhukar} } @article { ISI:000264991100040, title = {Mass transfer and solubility of CO and H-2 in ionic liquid. case of [Bmim][PF6] with gas-inducing stirrer reactor}, journal = {Industrial \& Engineering Chemistry Research}, volume = {48}, number = {8}, year = {2009}, month = {APR}, pages = {4075-4082}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Since the past decade, ionic liquids have gained significant importance as alternative solvents for catalysis applications. Many of the reactions evaluated in ionic liquids employ gases as substrates, and therefore it is important to know their solubility and mass transfer characteristics. This work reports for the first time both the solubility and volumetric gas-liquid mass transfer coefficient k(La) for hydrogen and carbon monoxide in 1-n-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) at three temperatures (293, 323, and 373 K) in relevance to hydroformylation reaction. The experimental data on the volumetric gas-liquid mass transfer coefficient are described by a dimensionless correlation for the bench-scale stirred tanks with gas-inducing impeller. k(La) values have also been evaluated for different [Bmim][PF6]-decane emulsions at 373 K.

}, issn = {0888-5885}, doi = {10.1021/ie801584p}, author = {Sharma, Amit and Julcour, Carine and Kelkar, Ashutosh A. and Deshpande, Raj Madhukar and Delmas, Henri} } @article { ISI:000283463600060, title = {Hydroformylation of 1-octene using [Bmim][PF6]-decane biphasic media and rhodium complex catalyst: thermodynamic properties and kinetic study}, journal = {Industrial \& Engineering Chemistry Research}, volume = {49}, number = {21}, year = {2010}, note = {21st International Symposium on Chemical Reaction Engineering (ISCRE 21), Philadelphia, PA, JUN 13-16, 2010}, month = {NOV}, pages = {10698-10706}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A chemical reaction engineering approach is reported to investigate the biphasic hydroformylation of I-octene using [bmim][PF6] ionic liquid. It is based both on a process parameter investigation (temperature, concentrations, and pressures) and a thermodynamic study of the reaction medium (gas liquid and liquid liquid equilibria). Initial rate data show complex behavior with respect to operating parameters and are best described by a rate equation based on a mechanistic model. Complete reaction scheme including isomerization is then modeled accounting from the time dependent concentration of the organic substrates measured in organic phase and recalculated in ionic liquid phase from liquid liquid equilibria.

}, issn = {0888-5885}, doi = {10.1021/ie100222k}, author = {Sharma, Amit and Lebigue, Carine Julcour and Deshpande, Raj Madhukar and Kelkar, Ashutosh A. and Delmas, Henri} } @article { ISI:000282663700004, title = {Synthesis of acrolein by gas-phase dehydration of glycerol over silica supported bronsted acidic ionic liquid catalysts}, journal = {Journal of Chemical Technology and Biotechnology}, volume = {85}, number = {10}, year = {2010}, month = {OCT}, pages = {1319-1324}, publisher = {JOHN WILEY \& SONS LTD}, address = {THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND}, abstract = {

BACKGROUND: Glycerol has become readily available as a byproduct from the biodiesel industry. High functionality and relatively low price make it a potential building block to produce value-added derivatives such as acrolein. RESULTS: Dehydration of glycerol to acrolein was performed over several silica supported Bronsted acidic ionic liquids as catalysts. All the catalysts prepared were active for the synthesis of acrolein (conversion of glycerol was observed in the range 35-90\% with selectivity to acrolein in the range 29-58\%). CONCLUSIONS: Catalyst prepared from triphenyl (3-sulfopropyl) phosphonium 4-methylbenzenesulfonate gave good activity and selectivity at 4 h reaction time. The conversion of glycerol decreased with increase in glycerol concentration. Higher temperature (325 degrees C) resulted in significantly lower conversion as well as selectivity to acrolein. With the use of two additional traps cooled to -7 degrees C, the selectivity to acrolein increased significantly for good catalysts. (C) 2010 Society of Chemical Industry

}, keywords = {acidic ionic liquids, acrolein, glycerol dehydration, supported catalyst}, issn = {0268-2575}, doi = {10.1002/jctb.2434}, author = {Munshi, Mudassir K. and Lomate, Samadhan T. and Deshpande, Raj Madhukar and Rane, Vilas H. and Kelkar, Ashutosh A.} } @article { ISI:000286850000004, title = {Oxidative carbonylation of amine using water-soluble palladium catalysts in biphasic media}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {334}, number = {1-2}, year = {2011}, month = {JAN}, pages = {20-28}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Application of water-soluble palladium catalysts for oxidative carbonylation of aniline to N,N{\textquoteright} diphenyl urea (DPU) has been reported. The water-soluble palladium catalysts prepared from sulfonated N-containing ligands were found to be highly stable under reaction conditions and easily recyclable due to insoluble urea product in the reaction medium. This is in contrast to the sulfonated phosphine ligands, which are vulnerable to oxidation under reaction conditions, showing poor activity and stability. Commercially available as well as laboratory synthesized ligands were used for preparing water-soluble palladium catalysts, for oxidative carbonylation of aniline. The best activity was obtained for Pd complex with disodium 2,2{\textquoteright}-bipyridine-4,4{\textquoteright}-disulfonate (Bipy-DS) ligand. Under optimized conditions Pd(BipyDS)Pd(OAc)(2) catalyst gave TOF of similar to 210h(-1) with aniline conversion of similar to 97\% with similar to 91\% selectivity for N.N{\textquoteright}-diphenyl urea. It was found that the catalyst was easily reusable up to five times, with negligible loss in the catalytic activity. The effect of reaction parameters was investigated and a plausible reaction mechanism has been proposed. (C) 2010 Elsevier B.V. All rights reserved.

}, keywords = {Amine, Biphasic catalysis, Carbonylation, Urea, Water-soluble palladium catalyst}, issn = {1381-1169}, doi = {10.1016/j.molcata.2010.10.018}, author = {Didgikar, Mahesh R. and Joshi, Sunil S. and Gupte, Sunil P. and Diwakar, Makarand M. and Deshpande, Raj Madhukar and Chaudhari, Raghunath V.} } @article { ISI:000306193700016, title = {Kinetics of the Heck reaction in biphasic organic-ethylene glycol medium}, journal = {Reaction Kinetics Mechanisms and Catalysis}, volume = {106}, number = {2}, year = {2012}, month = {AUG}, pages = {457-473}, publisher = {SPRINGER}, address = {VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}, abstract = {

PdCl2(bipy) was found to be an efficient and stable catalyst in biphasic medium (organic-glycol) for the Heck reaction. The kinetics of the Heck coupling of styrene with iodobenzene using the same catalyst was studied in a biphasic medium in a temperature range of 393-413 K. The rate was found to have a first order dependence tending to a fractional order, on the iodobenzene as well as catalyst concentration. The rate was found to have a complex dependence on the styrene concentration and passes through a maximum, showing typical substrate inhibition kinetics. The rate had a first order dependence on the base (morpholine) concentration. The trends observed for the influence of the different parameters on the activity of the catalyst are in agreement with the established mechanism for Heck reaction. An empirical rate model has been proposed to fit the observed rate data. The activation energy was found to be 72.91 kJ/mol. This is the first time that kinetic modeling of Heck reaction in a biphasic medium (organic-glycol) has been attempted.

}, keywords = {Biphasic catalysis, Heck reaction, kinetics, PdCl2(bipy) complex}, issn = {1878-5190}, doi = {10.1007/s11144-012-0437-1}, author = {Jagtap, Sangeeta Vijay and Deshpande, Raj Madhukar} } @article { ISI:000318393000043, title = {True water soluble palladium-catalyzed Heck reactions in aqueous-organic biphasic media}, journal = {Tetrahedron Letters}, volume = {54}, number = {21}, year = {2013}, month = {MAY}, pages = {2733-2736}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A stable water soluble palladium catalyst has been demonstrated for the Heck reaction in a biphasic medium (water-non-polar organic solvent). Biphasic Heck reactions reported till now generally employ a non-polar solvent along with an aqueous polar water miscible organic solvent as the second phase. The efficiency of the Pd complex of TOTPS [Trisodium salt of tri-(ortho-tolyl) phosphine tri sulfonate] for the vinylation of different aryl iodides and olefins is demonstrated. The advantages of a co-solvent for this biphasic system have also been shown. The catalyst has been recycled efficiently retaining the activity with negligible loss of catalyst and without leaching of the Pd. (c) 2013 Elsevier Ltd. All rights reserved.

}, keywords = {Aqueous biphasic catalysis, C-C coupling, Heck reaction, Water-soluble catalyst}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2013.03.067}, author = {Jagtap, Sangeeta Vijay and Deshpande, Raj Madhukar} }