Publications (19)36.26 Total impact
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Article: Magnetically recyclable γ-Fe2O3/HAP nanoparticles for the cycloaddition reactions of alkyne, halide and azide in aqueous medium
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ABSTRACT: A simple and novel γ-Fe2O3 supported on hydroxyapatite (HAP) heterogeneous catalytic system is described that is useful in the synthesis of disubstituted 1,2,3-triazoles from terminal alkynes and in situ generated organic azide in aqueous media; this greener methodology emerges as a new catalyst for one-pot synthesis of 1,2,3-triazoles in water without the addition of any reagent/base. The catalyst can be successfully recycled five times without significant loss of activity.RSC Advances 03/2013; -
Article: Sequential synthesis of β-amino alcohols using CeO2-ZrO2 bifunctional catalyst system
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ABSTRACT: CeO2–ZrO2 was explored as a bifunctional catalyst system Q3 for the synthesis of b-amino alcohols through epoxidation and subsequent aminolysis.Catalysis Science & Technology 02/2013; -
Article: A Benign synthesis of 2-amino-4H-chromene in aqueous medium using hydrotalcite (HT) as a heterogeneous base catalyst
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ABSTRACT: A simple and environmentally benign synthesis of 2-amino-4H-chromene is described using hydrotalcite as a solid base catalyst in aqueous medium. The catalysts were prepared by co-precipitation method and well characterized by various techniques such as XRD, FT-IR, SEM and the basicity found using the phenol adsorption method. The reusability of the catalyst, use of water as a green solvent and easy isolation of the product along with good yields make the present protocol sustainable advantageous than conventional methods.Catalysis Science & Technology 01/2013; -
Article: Oxidation of Alkyl Aromatics to Ketones by tert-Butyl Hydroperoxide on Manganese Dioxide Catalyst.
ChemInform 08/2012; 43(39). -
Article: Ecofriendly and facile Nano ZnO catalyzed solvent-free enamination of1,3-dicarbonyls
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ABSTRACT: Nano zinc oxide (Nano-ZnO) was explored as a reusable catalyst for the enamination of 1,3-dicarbonyls using diverse amines. To make the process environmentally viable, the reaction was carried out under solvent-free conditions and found to give good yield of desired products. The catalyst was characterized by various analytical techniques such as UV-spectroscopy, XRD, and TEM. The catalyst was found to be reusable up to four catalytic cycles without any appreciable loss in activity.Tetrahedron Letters 05/2012; 53:3857–3860. · 2.68 Impact Factor -
Article: Oxidation of Alkyl Aromatics to Ketones by tert-Butyl Hydroperoxide on Manganese Dioxide Catalyst.
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ABSTRACT: The catalytic activity of the manganese oxide was investigated for the oxidative functionalization of alkylaromatics to benzylic ketones using tert-butyl hydroperoxide (TBHP) as an oxidant. Manganese oxides of different types were tested for this reaction. Of all the oxides, the nano amorphous manganese dioxide exhibited significant catalytic activity and selectivity for the reaction. The nano amorphous MnO2/TBHP catalytic system could also be reused for six consecutive cycles with no considerable loss in catalytic activity.Tetrahedron Letters 04/2012; 53:2989-2992. · 2.68 Impact Factor -
Article: Choline chloride�2ZnCl2ionic liquid: an efficient and reusable catalyst for the solvent free Kabachnik–Fields reaction
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ABSTRACT: The choline based Zn containing deep eutectic mixture was applied as an efficient and eco-friendly ionic liquid catalyst for the one pot three-component synthesis of a-aminophosphonates under solvent-free condition at room temperature. The reactions were completed in short times and products were obtained in good to excellent yieldsTetrahedron Letters 02/2012; · 2.68 Impact Factor -
Article: Role of mixed metal oxides in catalysis science—versatile applications inorganic synthesis
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ABSTRACT: A variety of mixed metal oxides (MMOs), containing alkali, alkaline, rare earth and noble metals, and their applications are presented. In this mini review, we summarize versatile applications of mixed metal oxides in organic synthesis. A variety of reactions such as reduction, oxidation, multicomponent, Mannich, alkylation, condensation, deprotection, cycloaddition, hydroxylation, dehydration, dehydrogenation, transesterification, reactions involving biomimetic oxygen-evolving catalysts and other important C–C bond forming reactions are well presented on the surface of mixed metal oxides under a variety of reaction conditions. The scope of MMOs in important organic reactions, industrial applications, and green chemistry and recent applications of MMOs are well presented in this reviewCatalysis Science Technology. 02/2012; 2:1113–1125. -
Article: Sulphated yttria–zirconia as a regioselective catalyst system for the alcoholysis of epoxidesw
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ABSTRACT: It has been reported that sulphated yttria–zirconia efficiently catalysed the epoxide ring opening with a variety of alcohols under solvent free conditions to give corresponding b-alkoxy alcohols. In most of the cases reaction of epoxides with 11, 21 and 31 alcohols in the presence of catalytic amounts of SO 4 2À /Y x Zr 1Àx O 2 gives exclusively one regioisomer with excellent yields. The catalysts were characterized by XRD, SEM/EDAX, total acidity and TGA. The protocol is highly efficient, regioselective, atom economical, greener and applicable for a wide range of aliphatic and aromatic epoxides and alcohols with excellent yields of the corresponding b-alkoxy alcohols. The catalysts show reusability for up to four consecutive catalytic cycles without any significant loss of catalytic activity.Catalysis Scinece and Technology. 01/2012; 2:1493-1499. -
Article: Chemoselective transfer hydrogenation reactions over nanosizedc-Fe2O3 catalyst prepared by novel combustion route
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ABSTRACT: c-Fe2O3 catalyst was prepared by the novel combustion route. The as synthesized catalyst was characterized by several analytical techniques such as XRD, SEM, TG-DTA, etc. Chemoselective reduction of nitro compounds was studied over c-Fe2O3 using propan-2-ol as a hydrogen donor and KOH promotor in liquid phase reaction. The catalyst used for this synthetically useful transformation showed good activity.Catalysis Communications 02/2007; 8:1803–1806. · 2.99 Impact Factor -
Article: SO4-2/SnO2: Efficient, chemoselective and reusable catalyst for acylation of alcohols,phenols and amines at room temperature
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ABSTRACT: SO4 22/SnO2 was employed for the acylation of a variety of alcohols, phenols, and amines under solvent-free conditions at room temperature. This method showed preferential selectivity for acetylation of the amino group in the presence of a hydroxyl group. The reported method is simple, mild, and environmentally viable, using several other acid anhydrides at room temperature.Synthetic Communications 01/2007; 37(17):3011-3020. · 1.06 Impact Factor -
Article: Effect of quaternary ammonium cations on dye sorption to fly ash from aqueous media.
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ABSTRACT: The efficacy of the surface modification of fly ash by quarternary ammonium cations in the removal of dyes from aqueous solution is demonstrated. A series of organo-fly ash materials were synthesized by treating fly ash with quarternary ammonium cations such as tetraethylammonium, hexadecyltrimethylammonium, and benzyldimethyltetradecylammonium (TEA, HDTMA, and BDTDA). Two types of dyes were used for the investigation, disperse and anionic dyes. The effects of initial dye concentration, contact time, temperature, and the mechanism of dye sorption were investigated. The sorption was found to be affected by the structure and size of the quaternary ammonium cations as well as that of the dyes. Sorption of dyes was considerably enhanced by the surface modification. Thermodynamic parameters such as free energy (DeltaG0), enthalpy (DeltaH0), and entropy (DeltaS0) for the sorption process were also calculated.Journal of Colloid and Interface Science 12/2006; 303(2):477-83. · 3.07 Impact Factor -
Article: Treatment of oil spill by sorption technique using fatty acid grafted sawdust.
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ABSTRACT: Treatment of oil spills remains a challenge to environmental scientists and technologists. Among all the existing techniques used for oil treatment, sorption is a popular technique because it is cheap, simple and effective. Among the various sorbents used, sawdust appears to be the most attractive material in terms of cost, versatility and abundance. In the present work, the efficacy of surface modification of sawdust by fatty acids (oleic acid, stearic acid and decanoic acid) and vegetable oils (castor oil or mustard oil) is demonstrated. Sorption of seawater contaminated with crude oil and also weathered oil was greatly enhanced by the surface modification. The results show that oleic acid grafted sawdust (OGSD) has the best sorption capacity for crude oil as well as weathered oil.Chemosphere 09/2006; 64(6):1026-31. · 3.21 Impact Factor -
Article: A novel N-alkylation of amines by alkyl halides on mixed oxidesat room temperature
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ABSTRACT: Selective liquid phase N-alkylation of amines by alkyl halides using Al2O3–OK as a catalyst in the presence of acetonitrile at room temperature (30 �C) is described. The Al2O3–OK catalyst was characterized by XRD, SEM–EDXS, elemental analysis, particle size analysis, BET surface area, pore size and average pore diameter. The catalyst used for this synthetically useful transformation showed a considerable level of reusability as well as good activity.Catalysis Communications 08/2006; 8:576-582. · 2.99 Impact Factor -
Article: A novel catalyst for the Knoevenagel condensation of aldehydes withmalononitrile and ethyl cyanoacetate under solvent free conditions
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ABSTRACT: A novel, efficient and eco-friendly MgO/ZrO2 catalyst is put forward for the Knoevenagel condensation. The as synthesized catalyst MgO/ZrO2 was characterized by elemental analysis, XRD, FTIR, particle size, SEM–EDXS, average pore diameter, BET surface area analysis, and thermal gravimetric analysis. The Knoevenagel condensation of several aldehydes with ethyl cyanoacetate and malononitrile was carried out at 60 �C on MgO/ZrO2 catalyst in the absence of solventCatalysis Communications 03/2006; · 2.99 Impact Factor -
Article: Polyaniline film formation in hexadecyl trimethyl ammonium bromide admicelles on hydrous zirconia surface.
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ABSTRACT: Formation of a thin polyaniline film on hydrous zirconia (ZrO2) surface was carried out using adsorbed surfactant bilayers on ZrO2 as reaction sites. Aniline was adsolubilized in hexadecyltrimethylammonium bromide (HDTAB) admicelles formed on the surface of ZrO2 by adsorption. Subsequent polymerization of the adsolubilized aniline monomer showed effective conversion of aniline to polyaniline. The formation of the polyaniline coated ZrO2 has been confirmed by UV-visible spectroscopy, FT-IR spectroscopy, and conductivity measurements. Various parameters involved during the adsorption process were studied. Selection of pH 9.0 as the pH of all experimental feed solutions was governed by the knowledge of point of zero charge (PZC) of ZrO2. Effect of aniline concentration on HDTAB adsorption was studied and it was observed that increase in aniline concentration decreased the amount of HDTAB adsorbed on ZrO2. Addition of salt (0.05 M NaCl) in the feed solution increased HDTAB adsorption and drastically reduced the effect of aniline concentration on HDTAB adsorption.Journal of Colloid and Interface Science 12/2005; 291(1):92-7. · 3.07 Impact Factor -
Article: Regio- and chemoselective catalytic transfer hydrogenation of aromatic nitro and carbonyl as well as reductive cleavage of azo compounds over novel mesoporous NiMCM-41 molecular sieves.
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ABSTRACT: [reaction: see text] [corrected] Regio- and chemoselective reduction of nitroarenes and carbonyl compounds and reductive cleavage of azo compounds, including bulkier molecules, was achieved by the catalytic transfer hydrogenation method (CTH) using a novel nickel-containing mesoporous silicate (NiMCM-41) molecular sieve catalyst. In addition, the catalyst was also found to behave as a truly heterogeneous catalyst as the yield was practically unaffected.Organic Letters 12/2002; 4(24):4297-300. · 5.86 Impact Factor -
Article: Chemo-and regioselective reduction of nitroarenes, carbonyls and azo dyes over nickel-incorporated hexagonal mesoporous aluminophosphate molecular sieves
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ABSTRACT: Nickel-incorporated hexagonal mesoporous aluminophosphate (NiHMA) molecular sieves were found to be highly efficient heterogeneous catalysts for the chemo-and regioselective reduction of nitroarenes and carbonyl compounds as well as the reductive cleavage of azo functions, including bulkier substrates, by the hydrogen transfer method. The reduction of nitroarenes and carbonyl compounds to the corresponding amines and alcohols, respectively, is an important step in the industrial synthesis of dyes and of biologically active compounds. 1 In comparison to the commonly used reduction processes, which involve hazardous molecular hydrogen, 2 catalytic transfer hydrogenation (CTH) employing hydrogen donors, for example, propan-2-ol (Meerwein–Pondorff– Verley (MVP) reduction), is safer, highly selective and eco-friendly. 3 A wide variety of homogeneous metal complexes have been reported for the CTH process and most of them involve metal-catalyzed hydrogenations, complex hydrides or metal ions in solution. 4 However, these catalysts are not reusable due to various problems such as deactivation by metal precipitation or ligand degradation, separation difficulties, etc. On the other hand, the use of heterogeneous catalysts offers several advantages over homogeneous systems with respect to easy recovery and recycling of the catalysts as well as minimization of undesired toxic wastes. In this regard, Raney-Ni has been extensively used for heterogeneous CTH reactions. 5;6 Although, CTH reactions are very facile using this catalyst, they are not selective towards functional groups such as –X (X ¼ a halogen) and –NO 2 , and almost all labile functional groups undergo reduction under these reaction conditions. Furthermore, the Raney-Ni catalyst is flammable and presents hazards during handling. Hence, attention has been focused on the design of nickel-based oxide and nickel oxide supported catalysts. 7 However, these catalyst systems also have several drawbacks such as long reaction times, competing nucleophilic attack, the formation of by-products, low yields and the lack of true heteroge-neity, etc. In this communication, we report a very efficient, highly selective and rapid method for the reduction of nitroarenes and carbonyl compounds and the reductive cleavage of azo compounds using a nickel-containing hexagonal mesoporous aluminophosphate (NiHMA) molecular sieve catalyst. -
Article: Liquid phase catalytic oxidation of alcohols over mixed metal oxides
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ABSTRACT: Oxidation of alcohols was studied over CoO–CeO2 using tert-butyl hydroperoxide (TBHP) and n-hexane as a solvent in liquid phase reaction. The catalyst used for this synthetically useful transformation showed considerable level of reusability besides good activity.Catalysis Communications 9(1):186-193. · 2.99 Impact Factor
Top Journals
Institutions
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2012
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Institute of Chemical Technology, Mumbai
- Department of Chemistry
Mumbai, State of Maharashtra, India
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2007
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Gulbarga University
Gulbarga, State of Karnataka, India
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2005–2006
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University of Mumbai
- Department of Chemical Technology
Mumbai, State of Maharashtra, India
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