@article { ISI:000205747600006, title = {Extra-/intracellular biosynthesis of gold nanoparticles by an alkalotolerant fungus, trichothecium sp.}, journal = {Journal of Biomedical Nanotechnology}, volume = {1}, number = {1}, year = {2005}, month = {MAR}, pages = {47-53}, publisher = {AMER SCIENTIFIC PUBLISHERS}, type = {Article}, address = {25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA}, abstract = {

The development of reliable, eco-friendly processes for the synthesis of nanoscale materials is an important aspect of nanotechnology. As part of our ongoing investigation into the use of fungi for nanoparticle synthesis, we report herein that depending on the reaction conditions of the fungus Trichothecium sp. with aqueous gold ions, gold nanoparticle synthesis can be controlled to occur either within the biomass or extracellularly. Moreover, we have found that reaction of gold ions with the Trichothecium sp. fungal biomass under stationary conditions results in the rapid extracellular formation of gold nanoparticles of spherical, rod-like and triangular morphology whereas reaction of the biomass under shaking conditions resulted in intracellular growth of the nanoparticles. It is believed that on changing the reaction conditions of the fungus with gold ions, the enzymes and proteins which are being released into the medium under stationary conditions do not get released under shaking conditions resulting in the formation of extracellular or intracellular gold nanoparticles respectively. The gold nanoparticles are not toxic to the cells and the cells continued to grow after the biosynthesis of the gold nanoparticles in both the cases.

}, keywords = {Biosynthesis, enzymes, Fungus, Gold, Morphology Control, Nanoparticles}, issn = {1550-7033}, doi = {10.1166/jbn.2005.012}, author = {Ahmad, Absar and Senapati, Satyajyoti and Khan, Mohammad Islam and Kumar, Rajiv and Sastry, Murali} } @proceedings { ISI:000291657600151, title = {Ce-Al-MCM-41: an efficient catalyst for Mukaiyama-Michael reaction}, volume = {170}, year = {2007}, note = {15th International Zeolite Conference, Beijing, PEOPLES R CHINA, AUG 12-17, 2007}, month = {AUG}, pages = {1161-1166}, publisher = {Elsevier Science BV}, address = {Sara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, Netherlands}, abstract = {

The activity of cerium containing Al-MCM-41 mesoporous materials has been studied for carbon-carbon bond formation reaction like Mukaiyama-Michael reaction under mild liquid phase conditions. The catalysts were synthesized by hydrothermal method at 383 K for 24-36 h in Teflon-lined autoclave and characterized thoroughly by XRD, UV-VIS, TEM, EPR, XPS, (27)Al NMR, NH(3)-TPD, pyridine-IR and AAS in order to obtain well-ordered M41S type materials. The Mukiayama-Michael reactions between silyl enol ether and alpha,beta-unsaturated ketones give Michael product in very good yields (100\% selectivity). The catalysts were reusable.

}, isbn = {978-0-444-53068-4}, issn = {0167-2991}, author = {Kalita, Pranjal and Kumar, Rajiv}, editor = {Xu, R and Gao, Z. and Chen, J and Yan, W} } @article { ISI:000251244900038, title = {Eco-friendly, selective hydroxylation of C-7 aromatic compounds catalyzed by TS-1/H2O2 system under solvent-free solid-liquid-liquid-type triphase conditions}, journal = {Industrial \& Engineering Chemistry Research}, volume = {46}, number = {25}, year = {2007}, note = {Joint 6th International Symposium on Catalysis in Multiphase Reactors/5th International Symposium on Multifunctional Reactors (CAMURE-6/ISMR-5-), Pune, INDIA, JAN 14-17, 2007}, month = {DEC}, pages = {8657-8664}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Direct ring hydroxylation of aromatics, namely, anisole, toluene, and benzylchloride, using TS-1 catalyst, a MFI-type titanium silicate molecular sieve, dilute H2O2 as oxidizing agent, and water as reaction medium, was investigated under solid-liquid-liquid (SLL)-type triphase conditions. The aim was to study the relative influence of commonly used organic solvents, under solid-liquid (SL)-type biphase reaction conditions, as compared to that of water, on the conversion and product selectivity. Under solvent-free triphase conditions, the ring hydroxylation of anisole, toluene, and benzylchloride leads to significant enhancement in the conversion, turn-over frequency, and para-selectivity. However, in the case of benzyl chloride, no ring hydroxylation took place under biphase conditions (using acetone as solvent) contrary to significant ring hydroxylation (ca. 60\% H2O2 efficiency) under triphase aqueous medium conditions. The simple product recovery (phase separation of organic and aqueous layers) and use of water as reaction medium are other advantages. Since TS-1 is relatively hydrophobic, the reaction is hindered in the presence of organic solvents as they compete favorably with the substrate for diffusion inside the TS-1 channels. However, in the presence of water, the organic substrate competes favorably with water, leading to increased conversion and para-selectivity.

}, issn = {0888-5885}, doi = {10.1021/ie070088q}, author = {Mukherjee, P. and Bhaumik, Asim and Kumar, Rajiv} } @article { ISI:000243163000032, title = {Eco-friendly synthesis of epichlorohydrin catalyzed by titanium silicate (TS-1) molecular sieve and hydrogen peroxide}, journal = {Catalysis Communications}, volume = {8}, number = {3}, year = {2007}, month = {MAR}, pages = {379-382}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

In a mixed solvent system of acetonitrile and methanol, titanium silicate molecular sieve, TS-1, having MFI topology, efficiently catalyses the epoxidation of allyl chloride to the corresponding epichlorohydrin in excellent yields using dilute hydrogen peroxide (45\%) as an oxidizing agent. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {allyl chloride, epichlorohydrin, epoxidation, heterogeneous catalysis, selectivity, titanium silicalite-1}, issn = {1566-7367}, doi = {10.1016/j.catcom.2006.07.007}, author = {Pandey, Rajesh Kumar and Kumar, Rajiv} } @article {56}, title = {NCL-7, a novel all silica analog of polymorph B rich member of BEA family: synthesis and characterization}, journal = {Microporous and Mesoporous Materials}, volume = {101}, number = {1-2}, year = {2007}, note = {International Symposium on Zeolite and Microporous Crystals (ZMPC 2006), Yonago, JAPAN, JUL 30-AUG 02, 2006}, month = {APR}, pages = {108-114}, publisher = {Japan Assoc Zeolites}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

{Polymorph B-rich BEA type structure, NCL-7, was synthesized using hydrothermal method in fluoride medium using perchloric acid as promoter. The samples were characterized using XRD, low temperature N-2-adsorption and Si-29 MASNMR. As the structure of beta is highly disordered Rietveld refinement of powder XRD patterns is precluded. Phase composition is derived using the simulated patterns for the random intergrowths of polymorph A and B by DIFFaX. The stacking direction c{\textquoteright} is perpendicular to the a{\textquoteright}b{\textquoteright} plane of the layer. The composition of polymorph B is found to be ca. 60-65\%. Two other structures namely NCL-5 and NCL-6 with varying degree of polymorph B enrichment were also synthesized. Synthesis parameters such as effect of H2O/SiO2, TEAOH/SiO2, HClO4/SiO2 and crystallization temperature were studied thoroughly. The present article explains for the first time the synthesis and characterization of NCL-7, an analog of BEA type family with enrichment of polymorph B and its comparison with normal beta (*

}, keywords = {B-polymorph, DIFFaX, Promoter, Reitveld refinement, synthesis, zeolite beta}, issn = {1520-6106}, doi = {10.1016/j.micromeso.2006.10.033}, author = {Kadgaonkar, Mahesh D. and Kasture, Mahesh W. and Bhange, Deu S. and Joshi, Praphulla N. and Ramaswamy, Veda and Kumar, Rajiv} } @article { ISI:000243798400010, title = {Synergistic role of acid sites in the Ce-enhanced activity of mesoporous Ce-Al-MCM-41 catalysts in alkylation reactions: FTIR and TPD-ammonia studies}, journal = {Journal of Catalysis}, volume = {245}, number = {2}, year = {2007}, month = {JAN}, pages = {338-347}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

The acidic properties of Ce-x-Al-y-MCM-41 with different Ce/Al/Si atomic ratios were examined by pyridine-FTIR and ammonia-TPD methods. Both the density and the strength of the acid sites were considerably higher in the samples containing both Ce and Al than in the samples with only one of these substituents. The IR spectra of chemisorbed pyridine revealed that the Ce-Al-MCM-41 samples contained at least two distinct Lewis acid sites, L-2 (1595-1444 cm(-1)) and L-1 (1613-1452 cm(-1)), where the L-2/L-1 ratio increased progressively with increasing Ce/Al atomic ratio in a series of samples with similar Si/Al ratios. In addition, the density of the Bronsted acid sites (B) as well as the B/L-1 ratio increased with increasing Ce/Al molar ratio in these samples. The findings of this study help us understand the synergistic role played by Lewis and Bronsted acid sites in the catalytic activity of these catalysts for the benzylation of toluene. (c) 2006 Elsevier Inc. All rights reserved.

}, keywords = {ammonia-TPD, benzylation reaction, Ce-Al-MCM-41, Friedel-Crafts alkylation, pyridine-FrIR}, issn = {0021-9517}, doi = {10.1016/j.jcat.2006.10.022}, author = {Kalita, Pranjal and Gupta, Narendra M. and Kumar, Rajiv} } @article { ISI:000250399300012, title = {Synthesis and characterization of NCL-5, NCL-6 and NCL-7: new zeolites enriched with polymorph B of the BEA family}, journal = {Microporous and Mesoporous Materials}, volume = {105}, number = {1-2}, year = {2007}, month = {SEP}, pages = {82-88}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The synthesis of all-silica analogs of polymorph B-enriched zeolites of the BEA family denoted as NCL-5, NCL-6 and NCL-7 was realized hydrothermally at lower water content in fluoride medium using perchloric acid as promoter and terraethylammonium hydroxide as template. The present article explains the effect of different synthesis parameters on NCL-5, NCL-6 and NCL-7. The samples were characterized using XRD, low temperature N-2-adsorption, Si-29 MAS NMR and FTIR spectroscopy. The phase composition of the structures was derived using simulated patterns for the random intergrowths of polymorphs A and B using DIFFaX Code. The stacking direction c{\textquoteright} is perpendicular to the a{\textquoteright}b{\textquoteright} plane of the layer. The phase composition of polymorph B derived using DIFFaX code was found to be 90-95\%. 70-75\% and 60-65\% in NCL-5, NCL-6 and NCL-7, respectively. The gradual decrease of polymorph B concentration in these samples showed a correlation with the decrease in water/SiO2 molar ratio in gel. The framework FTIR spectral analysis of NCL-5 and all-silica-beta supported the postulation that significant enrichment of polymorph B in NCL-5 compared to that in all-silica-beta, as indicated by the relative intensities of pair of bands at 1097 and 1018 cm(-1) and 460 and 423 cm(-1) vibrations, leads to more tortuous channel structure associated with polymorph B. (C) 2007 Elsevier Inc. All riahts reserved.

}, keywords = {BEA family, NCL-5, NCL-6, NCL-7, polymorph B enrichment, synthesis, zeolites}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2007.05.063}, author = {Kadgaonkar, Mahesh D. and Kasture, Mahesh W. and Bhange, Deu S. and Joshi, Praphulla N. and Ramaswamy, Veda and Gupta, Narendra M. and Kumar, Rajiv} } @article { ISI:000252252400015, title = {Highly chemoselective catalytic system for hydrogenation of diketones to ketols: an environmentally benevolent system}, journal = {Catalysis Letters}, volume = {120}, number = {3-4}, year = {2008}, month = {JAN}, pages = {257-260}, publisher = {SPRINGER}, type = {Article}, address = {233 SPRING STREET, NEW YORK, NY 10013 USA}, abstract = {

Ru(Phen)(2)Cl-2 [Phen = Phenanthroline] anchored in organo-functionalized MCM-41 [Ru(Phen)(2)Cl-NH-MCM-41] efficiently catalyzes highly chemoselective hydrogenation of diketones to ketols (Sel. similar to 99\%) under environmentally benign tri-phasic (solid-liquid-liquid) reaction condition in aqueous medium.

}, keywords = {Chemoselective, dione, Hydrogenation, ketol, ruthenium phenanthroline, Water}, issn = {1011-372X}, doi = {10.1007/s10562-007-9278-3}, author = {Deshmukh, Amit A. and Kinage, Anil K. and Kumar, Rajiv} } @article { ISI:000254648100007, title = {In situ synthesis of Pt nanoparticles in SBA-15 by encapsulating in modified template micelles: size restricted growth within the mesochannels}, journal = {Journal of Materials Chemistry}, volume = {18}, number = {15}, year = {2008}, month = {FEB}, pages = {1765-1770}, publisher = {ROYAL SOC CHEMISTRY}, type = {Article}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A truly in situ and simple method is developed for nanoparticle incorporation within the mesochannels of SBA-15 involving dispersion of metal precursors in surfactant-modified polymer micelles. The diffusion of the precursor within the micellar structure is aided by interaction with the cationic head group of the surfactant leading to a unique method to facilitate the formation of highly disperse, uniform nanoparticles molded by the walls of the mesochannels. The nanoparticle incorporated mesoporous material has a highly enhanced surface area and adsorption capabilities in comparison to its parent materials without any pore blockage which makes this method ideal for the preparation of nanocatalysts.

}, issn = {0959-9428}, doi = {10.1039/b717991j}, author = {Prashar, Atul K. and Hodgkins, Robert P. and Kumar, Rajiv and Devi, R. Nandini} } @article { ISI:000252940800007, title = {Structure sensitivity of nano-structured CdS/SBA-15 containing Au and PtCo-catalysts for the photocatalytic splitting of water}, journal = {Catalysis Letters}, volume = {121}, number = {3-4}, year = {2008}, month = {MAR}, pages = {226-233}, publisher = {SPRINGER}, address = {233 SPRING STREET, NEW YORK, NY 10013 USA}, abstract = {

Photocatalysts containing nanocrystallites of cadmium sulphide dispersed in the channels of mesoporous silicate SBA-15 exhibited enhanced activity for visible-light mediated splitting of water, as compared to bulk CdS. Whereas the incorporation of 1 wt.\% Pt co-catalyst in CdS/SBA-15 led to a substantial increase in H-2 yield, Au at similar loading resulted in marginally decreased activity. The results indicate that the photocatalytic activity of CdS crystallites is structure sensitive. Similarly, the role of a noble metal may be associated with the particle size dependent micro-structural features, rather than its electronic properties such as the work function or the heat of adsorption of reactant or product molecules.

}, keywords = {nano-structured cadmium sulphide, Photocatalysis, role of noble metal co-catalyst, Splitting of water, structure sensitivity}, issn = {1011-372X}, doi = {10.1007/s10562-007-9319-y}, author = {Lunawat, Puja S. and Kumar, Rajiv and Gupta, Narendra M.} } @article { ISI:000265237700014, title = {Synthesis, characterization and catalytic performance of Sn-MCM-48 in solvent-free Mukaiyama-type aldol condensation reactions}, journal = {Applied Catalysis A-General}, volume = {358}, number = {1}, year = {2009}, month = {APR}, pages = {88-94}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The influence of various synthesis variables on the physico-chemical properties of mesoporous stannosilicate molecular sieves with MCM-48 structure (Sn-MCM-48) has been investigated. Sn-MCM48 has been used as a new heterogeneous catalyst in solvent-free Mukaiyama-type aldol reactions. Invariably, the beta-hydroxy ester selectivity was found to be 100\% irrespective of the conversion level. The product yield was found to increase, to reach a maximum (70\%), and then to decrease with the increase in tin content. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {Characterization, heterogeneous catalysis, Hydrothermal synthesis, Mesoporous molecular sieves, Mukaiyama-aldol condensation, Sn-MCM-48}, issn = {0926-860X}, doi = {10.1016/j.apcata.2009.02.001}, author = {Taralkar, U. S. and Kalita, Pranjal and Kumar, Rajiv and Joshi, P. N.} } @article { ISI:000284814600017, title = {Efficient heterogeneous catalytic system for chemoselective hydrogenation of unsaturated ketones in aqueous medium}, journal = {Polyhedron}, volume = {29}, number = {17}, year = {2010}, month = {NOV}, pages = {3262-3268}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

A highly chemoselective and green heterogeneous catalytic system of immobilized Ru(II)-phenanthroline complexes on amino functionalised MCM-41 material for the chemoselective hydrogenation of unsaturated ketones to unsaturated alcohols is demonstrated using water as a solvent The XRD and FTIR spectra show the highly ordered hexagonal nature of the MCM-41 even after encapsulation of the ruthenium complex The complex retains its configuration after anchoring as was confirmed by FTIR and UV-Vis analysis The detailed reaction parametric effect was studied for the hydrogenation of 3 methylpent-3-en-2-one to achieve complete conversion up to \>99\% chemoselectivity of 3-methylpent-3-en-2 ol The anchored heterogeneous catalysts were recycled effectively and reused five times with marginal changes in activity and selectivity The use of water as a solvent not only afforded high activity for the hydroge nation reaction compared to organic solvents but also afforded a green process Crown Copyright (C) 2010 Published by Elsevier Ltd All rights reserved

}, keywords = {1 10 Phenanthroline, alpha beta Unsaturated ketone, Chemoselective hydrogenation, mesoporous materials, ruthenium}, issn = {0277-5387}, doi = {10.1016/j.poly.2010.09.006}, author = {Deshmukh, Amit A. and Kinage, Anil K. and Kumar, Rajiv and Meijboom, Reinout} } @article { ISI:000285772600015, title = {Heterogenized Ru(II) phenanthroline complex for chemoselective hydrogenation of diketones under biphasic aqueous medium}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {333}, number = {1-2}, year = {2010}, month = {DEC}, pages = {114-120}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The chemoselective hydrogenation of acetylacetone to 4-hydroxypentan-2-one over immobilized ruthenium phenanthroline metal complexes in amino functionalized MCM-41 in biphasic aqueous reaction medium was investigated. The catalyst was characterized by XRD, TEM, surface analysis, FT-IR and UV-vis to understand the morphology, complex geometry, and XPS such that the oxidation state of the metal complex inside the MCM-41 framework could be understood. The use of water as a solvent, not only gives high activity and selectivity for hydrogenation of acetylacetone, but also gives a path for an environmentally safer process. The optimizations of ligand, metal to ligand ratio, the choice of solvent and other reaction parameters were studied in detail. The heterogeneous catalytic system gave a higher degree of chemoselectivity (99\%) towards 4-hydroxypentan-2-one as compared to homogeneous catalyst when hydrogenation was carried out using water as a solvent. The immobilized ruthenium-phenanthroline complex was easily separated and reused. (C) 2010 Elsevier B.V. All rights reserved.

}, keywords = {4-Hydroxypentan-2-one, acetylacetone, Chemoselective, Diketone, Hydrogenation, Phenanthroline, ruthenium, Water}, issn = {1381-1169}, doi = {10.1016/j.molcata.2010.10.005}, author = {Deshmukh, Amit A. and Kinage, Anil K. and Kumar, Rajiv and Meijboom, Reinout} } @article { ISI:000284454600041, title = {Ru(II) phenanthroline complex as catalyst for chemoselective hydrogenation of nitro-aryls in a green process}, journal = {Industrial \& Engineering Chemistry Research}, volume = {49}, number = {23}, year = {2010}, month = {DEC}, pages = {12180-12184}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Ru(II) Phenanthroline [Ru(II)(Phen)(n) where n = 1,2,3] complexes were used as highly chemoselective catalysts for hydrogenation of nitro aryls using molecular hydrogen in an aqueous media. Water, universal solvent, was used as a reaction mixture for hydrogenation of nitro-aryls to make the process green. The chemoselectivity in hydrogenation of substituted nitrobenzene to substituted aniline was obtained as high as \>99\% at about complete conversion of substituted nitrobenzene. The parametric effects, including effect of solvent, effect of ligand, effect of metal to ligand ratio, effect of temperature and pressure, were studied in detail to obtain the best results. The Ru(Phen)(n) was characterized by FTIR, UV-vis, and XPS.

}, issn = {0888-5885}, doi = {10.1021/ie1015969}, author = {Deshmukh, Amit A. and Prashar, Atul K. and Kinage, Anil K. and Kumar, Rajiv and Meijboom, Reinout} } @article { ISI:000290841300030, title = {Immobilization of 1,5,7-triazabicyclo [4.4.0] dec-5-ene over mesoporous materials: an efficient catalyst for michael-addition reactions under solvent-free condition}, journal = {Applied Catalysis A-General}, volume = {397}, number = {1-2}, year = {2011}, month = {APR}, pages = {250-258}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Immobilization of 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD, a bicylic guanidine base) over mesoporous material like SBA-15 has been found to be an excellent catalyst for Michael-addition of beta-nitro styrene with malonate. The reactions were performed under solvent-free condition at 373 K for 9 h. A wide variety of Michael donors and acceptors were investigated. Among them, high yield of Michael product was obtained for the reaction between p-Cl-nitrostyrene with dimethyl malonate. (C) 2011 Elsevier B.V. All rights reserved.

}, keywords = {1, 5, 7-triazabicyclo[4.4.0] dec-5-ene, beta-nitro styrene and malonate, mesoporous materials, Michael-addition}, issn = {0926-860X}, doi = {10.1016/j.apcata.2011.03.010}, author = {Kalita, Pranjal and Kumar, Rajiv} } @article { ISI:000293435400011, title = {Solvent-free mukaiyama-aldol condensation catalyzed by Ce-Al-MCM-41 mesoporous materials}, journal = {Microporous and Mesoporous Materials}, volume = {144}, number = {1-3}, year = {2011}, note = {16th IZC/7th IMMS Conference, Sorrento, ITALY, JUL 04-09, 2010}, month = {OCT}, pages = {82-90}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

MCM-41 samples containing Ce4+ and Al3+ in the network, designated as Ce-x-Al-MCM-41 (x = 0.0-0.04), were synthesized and characterized systematically. These samples exhibited higher catalytic activity for Mukaiyama-aldol condensations to produce beta-hydroxy carbonyl compounds under the solvent free conditions, compared to the samples containing either of the two cations. The product yield was found to depend on the electron donating/withdrawing characteristics of reactant molecules being responsible for the observed trend. Series of solvents were also investigated but considerably high yield of aldol products (similar to 95\%) could be achieved without using any solvents. In all the cases, the selectivity was found to be 100\%, typical of such Mukaiyama-aldol condensations. The higher catalytic activity of Ce-x-Al-MCM-41 is explained on the basis of certain new acid sites generated due to co-incorporation of Ce and Al cations. Published by Elsevier Inc.

}, keywords = {Acid catalyst, Ce-Al-MCM-41, Silyl enol ether and aldehyde, Silyl ketene acetal}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2011.03.027}, author = {Kalita, Pranjal and Gupta, Narendra M. and Kumar, Rajiv} } @article { ISI:000296933200001, title = {Solvent-free coumarin synthesis via pechmann reaction using solid catalysts}, journal = {Microporous and Mesoporous Materials}, volume = {149}, number = {1}, year = {2012}, month = {FEB}, pages = {1-9}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A solvent-free versatile and efficient methodology, reported here, allows the synthesis of coumarin by hydroxyalkylation of phenols with ethyl or methyl acetoacetate (via Pechmann reaction) using trifluoromethanesulfonic acid (trifle acid) functionalised Zr-TMS (Zr-TMS, zirconia based transition metal oxide mesoporous molecular sieves) catalysts with different loadings of triflic acid over Zr-TMS (5-25 wt.\%) where the total acid strength of acid functionalised Zr-TMS material is increased as increasing loading of triflic acid from 5 to 25 wt.\% leading to correspond increased higher catalytic activity. (C) 2011 Elsevier Inc. All rights reserved.

}, keywords = {Coumarin, Ethyl acetoacetate, Functionalization, Pechmann reaction, Resorcinol, Zr-TMS}, issn = {1387-1811}, doi = {10.1016/j.micromeso.2011.08.004}, author = {Kalita, Pranjal and Kumar, Rajiv} } @article { ISI:000340292800014, title = {Extracellular biosynthesis of metal sulfide nanoparticles using the fungus fusarium oxysporum}, journal = {Current Nanoscience}, volume = {10}, number = {4}, year = {2014}, month = {JUL}, pages = {588-595}, publisher = {BENTHAM SCIENCE PUBL LTD}, address = {EXECUTIVE STE Y-2, PO BOX 7917, SAIF ZONE, 1200 BR SHARJAH, U ARAB EMIRATES}, abstract = {

The development of reliable, eco-friendly processes for the synthesis of nanomaterials is an important aspect of nanotechnology. One approach that shows immense potential is based on the biosynthesis of nanoparticles using microorganisms such as bacteria. In this report, we demonstrate the extracellular biosynthesis and complete characterization of metal sulfide (PbS, ZnS, MnS and NiS) nanoparticles using fungus, Fusarium oxysporum. We observed that the exposure of aqueous solution of 1 mM metal sulfate to fungus Fusarium oxysporum resulted in the formation of highly stable technologically important metal sulfide semiconductor nanoparticles. Fusarium oxysporum synthesizes lead sulfide and zinc sulfide nanoparticles of fractal type structure whereas manganese sulfide and nickel sulfide nanoparticles are of variable polydispersed morphology. The variable morphology may be due to the dissimilar interaction of metal sulfide nanoparticles with capping proteins secreted by the fungus in solution. The nanoparticles solution is found to be extremely stable with little evidence of aggregation even after a month of storage. The long term stability of the nanoparticles is due to the proteins secreted by fungus in the nanoparticle solution which bind to the surface of the nanoparticles and thus prevent aggregation.

}, keywords = {Biosynthesis, enzymes, fungi, metal sulfide, Nanoparticles}, issn = {1573-4137}, author = {Senapati, Satyajyoti and Syed, Asad and Khan, Shadab and Pasricha, Renu and Khan, Mohammad Islam and Kumar, Rajiv and Ahmad, Absar} }