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Manganese oxide octahedral molecular sieve (OMS-2) nano-rods were synthesized in the presence of HNO3 and then ion-exchanged with Ru3+ to obtain Ru-modified scaffolds abbreviated as Ru-OMS-2. Various techniques including X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDS), X-Ray photoelectron spectroscopy (XPS), and EDS mapping analysis were used to characterize the structure of the obtained product. Ru-OMS-2 was then used as a reusable heterogeneous catalyst in the selective oxidation of polycyclic aromatic hydrocarbons and heterocyclic compounds such as olanzapine and benzothiophene in an aqueous solution. Under mild reaction conditions, excellent yields of the desired products (10 examples, 55–99% yield) were obtained with high selectivity, and the catalyst retained activity for several consecutive cycles with a reasonable loss of activity (7.5% after 10 runs). [ABSTRACT FROM AUTHOR]

A highly efficient recoverable and reusable heterogeneous Zn-catalyst, chitosan supported ZnSO4. 7H2O (designated as Zn@CS) is synthesized via a simple synthetic route. Low catalyst loading, need of aqueous reaction media and sharp reduction of time requirement in comparison to the previously reported methodologies are some special features of the established Zn catalyzed direct azide-alkyne cycloaddition reaction. Zn@CS-catalyst is also suitable for multicomponent synthesis of 4-aryl-NH-1,2,3-triazoles from different derivatives of benzaldehyde. An inexpensive and environmentally benign deep eutectic solvent (DES), ChCl:PEG-400:Glycerol as a suitable reaction media accelerates these reactions leading to excellent yields of NH-triazoles. Based on literature report a plausible mechanism has been suggested for ZnAAC reaction. [ABSTRACT FROM AUTHOR]

In this study, we describe the synthetic of uranyl nitrate ion functionalized MOFs linked by carboxyl, which displays block shape crystals structure. The as-prepared uranyl-MOF has been efficiently utilized as heterogeneous catalyst for selective aerobic oxidation of sulfides under visible-light irradiation. Photochemistry of extended MOFs including uranyl nitrate ion has been examined. The sulfoxidation reaction proceeds with good yields for a large variety of different sulfides. This process is carried out under visible light conditions, methanol as single solvent, and the uranyl-MOF material can be recycled up to five times. Sulfoxidation reaction mainly proceeds through an electron and energy transfer mechanism of oxygen in uranyl nitrate ion. In this study, we describe the synthetic of uranyl nitrate ion functionalized MOFs. The as-prepared uranyl-MOF was efficiently utilized as heterogeneous catalyst for selective aerobic oxidation of sulfides under visible-light irradiation. Photochemistry of extended MOFs including uranyl nitrate ion has been examined. [ABSTRACT FROM AUTHOR]

The present effort describes facile and environmentally benign synthesis of 4-thiazolidinone via oxidative cyclocondensation of benzyl alcohols, various substituted aromatic anilines and thioglycolic acid using a Co-Al hydrotalcite based heterogeneous catalyst (Co@HT) in methanol act as a solvent. We have synthesized three types of Co@HT with different molar ratio Co@HT-2 (1:1), Co@HT-3 (2:1), Co@HT-4 (3:1). Characterization of synthesized Co@HT catalyst using various analysis techniques such as FT-IR, powder XRD, SEM, XPS, EDS, DTG-TGA and N2 physical adsorption. Among the synthesized hydrotalcite, Co-HT-3 exhibit admirable catalytic activity towards oxidation of benzyl alcohol followed by cyclocondensation of respective aldehydes, anilines and thioglycolic acid into the corresponding 4-thiazolidinones in methanol at 60 οC using O2 as a oxidant. Furthermore, after end of the reaction, the catalyst is easily recovered and eco-friendly without any considerable loss in its catalytic efficiency. [ABSTRACT FROM AUTHOR]

An efficient route was developed for the synthesis of a new polymer, porous cross-linked poly(ethyleneamine)-polysulfonamide (PEA-PSA), as an organic support for the imobilization of CuI nanoparticles (PEA-PSA@CuI). The resulting catalyst works as an efficient recyclable heterogeneous catalyst for the synthesis of imidazo[1,2-a] pyridines from the reaction of 2-aminopyridine, aldehydes and phenylacetylene. The method possesses significant advantages including: easy purification, functional group tolerance, recyclability of the catalyst and synthesis of new derivatives in high to excellent yields and short reaction times. [ABSTRACT FROM AUTHOR]

A green recyclable cellulose-supported Pd(salen)-type catalyst was synthesized through sequential three steps: chlorination with thionyl chloride, modification by ethylenediamine, and the formation of Schiff base with salicylaldehyde to immobilize palladium chloride through multiple binding sites. This novel heterogeneous cellulosic Pd(salen)-type catalytic complex was fully characterized by FT-IR, SEM, TEM, XPS, ICP-AES and TG. The traditional cross-coupling chemistry, such as Suzuki, Heck, Sonogashira, Buchwald–Hartwig amination and etherification, was then investigated in the presence of the above cellulose-palladium nanoparticle. Studies have shown that the synthesized catalyst shows high activity and efficiency for all types of transformations, providing the corresponding carbon–carbon or carbon–heteroatom coupling products in a general and mild manner. Furthermore, the catalyst demonstrates high to excellent yields and is easily recycled by simple filtration for up to twelve cycles without any significant loss of catalytic activity. [ABSTRACT FROM AUTHOR]

Here we first designed, synthesized and compared Ni, Ag and Ce doped manganese oxide octahedral molecular sieves, (Ni-OMS-2, Ag-OMS-2 and Ce-OMS-2) for the catalytic degradation of organic dyes, such as reactive red 2, acid orange 7, methylene blue, and rhodamine B, in the presence of potassium peroxymonosulfate in aqueous solutions. These results show that the catalytic efficiency increases in the order of Ce-OMS-2 < OMS-2 < Ag-OMS-2 < Ni-OMS-2 for organic dyes degradation, which is in accordance with the concentration of oxygen vacancy defects on the surface of materials. Then pH condition and various amounts of Ni-OMS-2, organic dye and potassium peroxymonosulfate concentration have also been investigated for the reactive red 2 degradation. In addition, TEM and XRD have confirmed the heterogeneous catalyst Ni-OMS-2 has been successfully recycled at least 5 times with a very slight reduction efficiency by the simple filtration. We have designed, synthesized and compared Ni, Ag and Ce doped OMS-2, (Ni-OMS-2, Ag-OMS-2 and Ce-OMS-2) for the degradation of organic dyes. And they show the catalytic efficiency increases in the order of Ce-OMS-2 < OMS-2 < Ag-OMS-2 < Ni-OMS-2 for the degradation. [ABSTRACT FROM AUTHOR]

The immobilization of a copper complex by covalent anchoring of 2-hydroxybenzophenone on the surface of amine-functionalized magnetic nanoparticles was reported. The structure and morphology of the catalyst was characterized by different techniques such as Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron micrograph (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), vibrating sample magnetometer (VSM) and inductively coupled plasma (ICP) spectroscopy. This efficient and cost effective catalyst was applied in the N-arylation reaction and the products were obtained in good to excellent yields in short reaction times. The cost-effective catalyst demonstrated high stability, which could be facilely separated from the reaction mixture by applying an external magnet and recycled at least four times with only a slight decrease in its activity. [ABSTRACT FROM AUTHOR]

Abstract: Pd nanoparticles supported on humic acid-coated nanoferrites as magnetically-recoverable catalyst was expediently prepared from inexpensive precursors and characterized by techniques such as SEM, TEM, XPS, FT-IR, XRD, ICP-AES, EDX. The as made catalyst displayed an admirable catalytic activity towards the Suzuki-Miyaura cross-coupling reaction of aryl halides (or) aryl diazonium salts with aryl boronic acid in non-toxic solvent EtOH/water under mild conditions. The same catalyst showed high efficiency for the Heck reaction of aryl halides with styrene was carried out with high efficiency offering good yields under ligand-free conditions. Additionally, the reduction of olefins using molecular hydrogen was also achieved using the same catalyst under ambient and base-free conditions affording the products in good to excellent yields. The magnetic activity of nano-Fe3O4 allowed the effortless recovery of the catalyst and demonstrated subsequent recyclability up to 5 cycles without a significant loss in the activity.Graphical Abstract: [ABSTRACT FROM AUTHOR]

In this work, we have described the versatility of low metal loading copper nanoparticles immobilized on nanocellulose for the controlled and selective oxidation of sulfides to sulfoxides and primary alcohols to aldehydes using green oxidant at room temperature. Aromatic, aliphatic and heterocyclic sulfides were oxidized to their corresponding sulfoxides with high yields without formation of over oxidized sulfones. Similarly, benzylic, allylic and aliphatic alcohols were selectively oxidized to aldehydes without traces of carboxylic acids in good to excellent yields.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Present work reports the direct synthesis of amides from oxidative coupling of benzyl alcohols with various N-substituted formamides using a cobalt-hydrotalcite (Co-HT) derived catalyst. The Co-HT derived catalysts (Co-HT-2, Co-HT-3 and Co-HT-4 having Co2+/Al3+ molar ratio in the catalyst preparation mixture as 1/1, 2/1 and 3/1 respectively) were prepare following a co-precipitation method and characterized well by powder XRD, XPS, FEG-SEM, EDS, DTG-TGA, FT-IR and N2 physisorption measurements. A range of functional amides were obtained in good yields from oxidative coupling of various substituted benzyl alcohols and a range of N-substituted formamides using Co-HT-3 catalyst and oxidant TBHP. Mechanistic investigation suggests that the amidation reaction is associated with the formation and coupling of radical species. Furthermore, the Co-HT derived catalyst was easily recoverable and recyclable with retained high catalytic activity towards the oxidative coupling of benzyl alcohol with DMF.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Many synthetic methods have been reported to construct an aryl-nitrogen bond. But they mainly suffer from the usage of expensive ligands. Herein, we report highly effective, heterogeneous, reusable and ligand-free nanocatalyst for the Buchwald-Hartwig coupling reaction under aerobic condition. Wafer-like structure with nano-porous nature of AlO(OH) was identified with TEM and BET surface area analyses. Zero valent Pd nanoparticles (with less than 10 nm crystallite size which strongly evident from TEM analysis) were observed in XRD pattern, which was further confirmed by XPS studies. The reaction conditions were optimized and the scope of the reaction was extended with various aryl halides and aniline using low amount of Pd (0.31 mol%) based heterogeneous catalyst. Heterogeneity, reusability and stability (confirmed by XRD) were found to be reasonable. Use of meagre amount of Pd and the ligand-free aerobic condition make this system economically as well as environmentally feasible. Graphical Abstract: [ABSTRACT FROM AUTHOR]

Several organic-inorganic polyoxometalate-based frameworks such as HSiW-MOF, PMo-MOF, HPMo-MOF and PW-MOF were prepared and characterized by Elemental analysis, UV-Vis, FT-IR and XRD. Thioanisole was used as the model of sulfur compound in the oxidation reaction. The effects of reaction time, type of solvent, amount of catalyst and oxidants in this catalytic system were investigated. At optimum conditions, PMo-MOF and PW-MOF are more active catalysts with respect to HO. Oxidation of various sulfides to sulfoxides using 30 % aqueous hydrogen peroxide as oxidant under mild reaction conditions in 90-100 % conversion and 95-100 % selectivity to sulfoxideswas performed. Both catalysts showed high catalytic activity in the oxidation of different sulfides with actively functional groups such as the hydroxyl group and C=C bonds. The heterogeneous catalyst (PW-MOF) could be recovered easily and reused five times without significant loss of its catalytic activity. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Mesoporous MgAlO spinel (MAO), prepared via one-pot evaporation induced self-assembly strategy, was reported here as an acid-base bifunctionalization catalyst for the reaction for ethyl methyl carbonate from dimethyl carbonate and diethyl carbonate. The physical/chemical properties of MgAlO were characterized by X-ray powder diffraction, N adsorption-desorption, temperature programmed desorption and Fourier transform infrared. The effects to the reaction by adjusting the catalyst amount and reaction time were tested. The transesterification induced by MAO is much faster, and meantime, the thermal stability of MAO is much higher. Moreover, the catalyst can be used directly after filtration without drying and reused for at least five times with only 1.2 % loss in catalytic activity. Graphical Abstract: MgAlO as an acid-base catalyst was synthesized, characterized and successfully applied for the transesterification of DMC with DEC synthesizing EMC.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Recently, gold has been proposed as an active phase for the hydrogenation of nitro-arenes. This metal has been rarely used in hydrogenation reactions because gold does not possess hydrogen chemisorption capacity. However, small gold particles behave differently and they may be able to chemisorb hydrogen to same extent, leading to possible activity in hydrogenation reactions. This may provide an advantage because the reactions catalyzed by highly dispersed gold particles may be better controlled. In this work, TiO and SiO supported Au catalysts were prepared by the deposition-precipitation method using urea and NaOH to precipitate the metallic component at different temperatures and hydrogen pressures. The metal loading for all the catalysts was 1 wt%. The catalysts were characterized by X-ray diffraction, high resolution transmission electron microscopy among others. The catalysts were then evaluated in the hydrogenation of nitrobenzene in a batch type reactor at 25 °C. All the catalysts were active in the hydrogenation reaction and the major obtained product was aniline. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Azo linked Schiff-base[L] complexes of Mn(II)( 1), Cu(II)( 2) and Co(II)( 3) obtained by template method, in the reaction of 4-(benzeneazo) salicylaldehyde with 1,2-propanediamine in the present of metal acetate, respectively. Complexes are used as catalyst for oxidation of cyclohexene with tert-butylhydroperoxide (TBHP); oxidation of cyclohexene catalyzed by these complexes gave 2-cyclohexene-1-one and 2-cyclohexene-1-ol as major products. Conversion of cyclohexene achieved was 95-100% with ( 1), ( 2) and ( 3), with selectivity of 57, 92 and 100% for 2-cyclohexene-1-one, respectively. The encapsulated Cu(II) complex (Cu-NaY) catalyzes the oxidation of cyclohexene using TBHP as oxidant in good yield. (Cu-NaY) under optimized reaction condition gave three reaction products. A maximum of 100% conversion of cyclohexene has been achieved where selectivity of 2-cyclohexene-1-one was 83%. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Nearly monodisperse polystyrene nanospheres coated with platinum have been synthesized and applied successfully in the cinchona alkaloid-modified enantioselective hydrogenation of ethyl pyruvate. During the catalyst preparation broadly varied experimental conditions were used resulting in several catalysts with different properties. The effect of hydrogen pressure, solvent, modifier and polystyrene nanoparticle size on the enantioselectivity was also studied. Based on the results the effect of support on the mechanism of the enantiodifferentiation has been discussed. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

In the oligomerization of ethene, the chain-length distributions obtained over heterogeneous nickel catalysts at a low reaction temperature (ca. 110 °C) depend on the acidity of the silica–alumina support, the nickel loading and the olefin feed. Most significantly, ion-exchanged catalysts based on a silica–alumina of high acidity (ca. 0.7 mass% Ni), and those based on a highly-exchanged medium-acidity support (ca. 1.6% Ni), show a distinct superimposed activity for the dimerization of the intermediate butenes. This causes a desirable shift to higher hydrocarbon products, and it is possible to obtain 41 mass% C10+ oligomers, while the corresponding value predicted from Schulz–Flory statistics is only 24 mass%. No such deviation from Schulz–Flory statistics is observed in propene oligomerization. [ABSTRACT FROM AUTHOR]

Anionic platinum carbonyl clusters supported on quaternary amine functionalized cross-linked polystyrene, i.e., anion exchangers, are effective precatalysts for the hydrogenation of methyl pyruvate to methyl lactate. Kinetic data has been obtained for anion exchangers with different quaternary groups. Highest observed rate constant and enantioselectivity are obtained with cinchonine funtionalized resin. The kinetic data also indicates saturation kinetics. The decarbonylated used catalyst could be recarbonylated to give a material spectroscopically (infrared) equivalent to freshly anchored cluster. [ABSTRACT FROM AUTHOR]