Sharif Digital Repository

Incorporation of calcium(ii), zinc(ii) and aluminium(iii) to manganese oxides greatly improved the activity of manganese oxide towards the epoxidation of olefins in the presence of anhydrous tert-butyl hydroperoxide as an oxidant  

Co/SBA-15 nanoparticle catalysts (CoNP) were prepared using a commonly adapted synthetic route and then utilised for esterification and amidation reactions using aromatic and linear chain compounds for the production of long chain esters and amides. The study shows that the use of CoNP catalysts favours the use of aromatic reactants with electron donating substituents specifically in the para position. For the amidation reaction, good to excellent yields were obtained demonstrating tolerance towards differently substituted aromatic compounds. Overall, the synthesized catalysts proved to be efficient and highly versatile, and recyclable under the investigated conditions  

Oxido-peroxido W(VI)-histidine–MgAl-layered double hydroxide composite was prepared by using MgAl-layered double hydroxide as a host and oxido-peroxido W(VI)-histidine complex as a guest. The composite was characterized by XRD, IR, EDX,SEM and TEM techniques. This composite is tested for catalytic selective sulfoxidation reactions using hydrogen peroxide as oxidant showing good to moderate conversion along with high selectivity. Copyright © 2018 John Wiley & Sons, Ltd  

Activated layered manganese oxides with deposited nano-sized gold or silver were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, atomic absorption spectroscopy and energy-dispersive X-ray mapping. Here, we report that Au or Ag nanoparticles deposited on layered Mn oxides improve the catalytic activity of the Mn oxides toward the epoxidation of olefins in the presence of H2O2 and NaHCO3  

An environmentally benign, aqueous synthesis of 1,2-azidoalcohols via regioselective ring opening of their epoxides using magnetic imidazolium based dicationic room temperature ionic liquid, [pbmim](FeCl4)2, as an efficient magnetic phase transfer catalyst in water has been described. The present approach offers the advantages of clean reaction, simple methodology, short reaction time, high yield, easy purification and reusable catalyst  

Supported iron oxide nanoparticles are found to be efficient and recoverable catalyst in the selective oxidation of thiols to their corresponding disulfides using hydrogen peroxide as green oxidant at room temperature. The protocol features an easy work-up, simplicity and the utilizing mild reaction conditions, as well as high selectivity toward disulfides, are highly advantageous compared to alternative reported methodologies. The supported iron oxide nanoparticles could be easily recovered and reused several times without any loss of activity. ICP-MS results prove that there is no metal leaching observed, and demonstrating the stability of the catalyst under the reaction conditions  

Nano-sized particles of manganese oxides have been prepared by a very simple and cheap process using a decomposing aqueous solution of manganese nitrate at 100 °C. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction spectrometry have been used to characterize the phase and the morphology of the manganese oxide. The nano-sized manganese oxide shows efficient catalytic activity toward water oxidation and the epoxidation of olefins in the presence of cerium(iv) ammonium nitrate and hydrogen peroxide, respectively  

We have evaluated the catalytic activity of a molybdenum(VI) oxo-peroxo complex through the oxidation and reduction of sulfur-based compounds. Arylalkyl, diaryl and dialkyl sulfides are selectively oxidized to corresponding sulfoxides, with tert-butyl hydroperoxide (TBHP), in the presence of MoO(O 2)(phox) 2 complex as catalyst. This molybdenum complex was also found to be an efficient catalyst for the deoxygenation of sulfoxides to sulfides with PPh 3 in excellent yields and chemoselectivity  

The effects of six synthetic imidazolium-based ionic liquids (ILs) on the CuII-catalyzed chemiluminescence of lucigenin (Luc-CL) in the pH range 6.0-11 were investigated. Preliminary experiments found that the CL emission was strongly enhanced or inhibited in the presence of the ILs. The degree of enhancement or inhibition of the CL intensity in the presence of each IL was related to the molecular structure of the IL, the medium used, and the pH. The maximum enhancement of the CL intensity was observed at pH 9.0 (amplification factor=443). This decrease in the pH at which maximum CL enhancement occurred and the substantial signal amplification of the Luc-CL may be related to a strong... 

The use of 1,3-bis(N-heterocyclic)carbene ligands with different alkyl wingtip groups (alkyl = methyl, isopropyl and tert-butyl) is an effective method for the palladium-catalysed direct S-arylation of methylphenyl sulfoxide and C-C coupling of various of aryl halides with alkenes. The reactions proceed in moderate to good yields. Interestingly, it is shown experimentally that, by using bulkier bidentate N-heterocyclic carbene ligands, more selective catalytic systems towards cis products in Heck coupling reactions can be achieved  

The present work reports the synthesis of a Pt-modified NiO–Al2O3 nanocomposite derived from graphene-supported layered double hydroxide (Pt–NiO/G) and demonstrates its catalytic activity. The resulting Pt–NiO/G nanocomposite was characterized by FT-IR, XRD, FE-SEM, TEM and XPS techniques and used for catalytic reduction of p-nitrophenol (P-NP) to p-aminophenol (P-AP). The influence of graphene on catalytic activity was comparatively considered by preparation of Pt–NiO nanoparticles derived from layered double hydroxide. The superior catalytic performance of Pt–NiO/G was ascribed to the synergistic effect between Pt and NiO. Furthermore, reduction of P-NP was considered to follow a... 

Metal Organic Frameworks (MOFs) have received enormous attention in catalysis field due to their special structures and various promising applications. One of the intriguing applications of MOFs is utilization of them as precursors for synthesis of metal oxide nanomaterials. Base on this strategy, in this work, we have applied Cu-MOF to prepare a series of noble metal nanoparticles (Ag and Au) decorated CuO (M/CuO) as efficient catalyst. As-prepared nanocomposites were characterized by various analytical techniques and their catalytic performances appraised by using of the catalytic reduction of p-nitrophenol to p-aminophenol as a reliable model reaction. Experimental results suggest that... 

The use of 1,3-bis(N-heterocyclic)carbene ligands with different alkyl wingtip groups (alkyl = methyl, isopropyl and tert-butyl) is an effective method for the palladium-catalysed direct S-arylation of methylphenyl sulfoxide and C–C coupling of various of aryl halides with alkenes. The reactions proceed in moderate to good yields. Interestingly, it is shown experimentally that, by using bulkier bidentate N-heterocyclic carbene ligands, more selective catalytic systems towards cis products in Heck coupling reactions can be achieved. Copyright © 2016 John Wiley & Sons, Ltd  

Palladium(II) have been immobilized into the nano magnetic Fe3O4 which was functionalized with glucose in order to achieve a one-pot synthesis of 2-substituted benzoxazole derivatives with high yields in the diverse range of organic solvents. The nano catalyst is highly dispersive in polar solvents and can be easily recovered and reused for 6 runs without significant loss of its activity. Finally, the catalyst was fully characterized by FT-IR, TGA, CHN, SEM, EDX and atomic absorption spectroscopy. Copyright © 2018 John Wiley & Sons, Ltd  

Palladium nanoparticles supported on polyoxometalate as a solid carrier were successfully prepared and evaluated as a heterogeneous nanocatalyst for the Mizoroki-Heck cross-coupling reactions. This supported catalyst was characterized by a set of techniques, including XRD, chemical analysis (ICP-OES), IR spectroscopy, TEM and FE-SEM analyses. Poly (ethylene glycol) was employed as an environmentally friendly solvent for coupling reactions. The various fundamental reaction parameters that influence the efficiency of the reaction and yield of the desired reaction products were optimized. This catalytic system showed good activities and evolve a strategy for achieving five times catalyst and... 

Various challenging pollutants are produced in the environment by organic materials of diverse industries including leather, paint, and textile. Nowadays, it is vital to develop efficient manners regarding the fundamental issues and removing pollutants. Such pollutants can be effectively removed from the environment through heterogeneous catalysts. Recently, a huge deal of interest has been attracted by hydrogel-based metal catalysts as heterogeneous and efficient catalysts. In this regard, silver with its unique features is suitable for environmental remediation. Hence, the present review deals with summarizing the present advances in the synthesis of silver-based hydrogel catalysts, as... 

Co(salen)-type [where salen = di-(salicylal)-ethylenediimine] complexes were shown to be efficient catalysts in the oxidation of 2-phenylpropane (cumene) by dioxygen primarily to 2-phenyl-2-propanol (cumyl alcohol), 2-phe-nylpropene (a-methylstyrene), and 1-phenylethanone (acetophenone) applying 1H NMR spectroscopy and gas chromatography-mass spectrometry (GC-MS). The effect of substitution on the ligand was also monitored in both oxygen-absorption and the catalytic reaction. Based on these results, the trend observed for the production of a-methylstyrene and cumyl alcohol were parallel to dioxygen uptake by the catalyst in neat cumene, while acetophenone productions obeyed a non-linear... 

Manganese doped on cubic phase nanoparticles of ZrO2 was synthesized by an impregnation method. These novel particles were carefully analyzed by various chemico-physical methods. The catalytic degradation of an organic dye, methylene blue, in the presence of Mn-doped ZrO2 nanoparticles, as well as ZrO2 nanoparticles as catalyst with aqueous hydrogen peroxide, H2O2, as an oxidizing agent has been studied in aqueous solution at room temperature. Effects of solution pH, catalyst composition and radical scavenging agents on the degree of degradation of methylene blue were also studied. Finally, the recoverability and reusability of the... 

Readily prepared copper nanoparticles supported on CeO2 have been found to effectively catalyse the 1,3-dipolar cycloaddition (CuAAC) of a variety terminal alkynes and organic azides generated in situ from sodium azide and different organic halides furnishing the corresponding 1,2,3-triazoles in excellent yields. Cu nanoparticles supported on CeO2 have been characterized by X-ray diffraction analysis, energy dispersive X-ray analysis, scanning electron microscope and transmission electron microscope. The salient features of the present protocol are shorter reaction time, mild reaction conditions, reusability of the catalyst, and applicability to a wide range of substrates. © 2016 Elsevier... 

Cu-MOF/rGO nanocomposite was synthesized by a one-step hydrothermal method and used as proper support for Cu2O particles. Various microscopic and spectroscopic methods were applied to characterize the morphology of Cu2O/Cu-MOF/rGO nanocatalyst. Catalytic results of 4-nitrophenol reduction in the presence of NaBH4 indicate that as-synthesized nanocomposite shown significant improved activity compared with pure Cu2O particles. Enhanced catalytic performance of nanocomposite can be ascribed to the high adsorption ability of Cu-MOF and effective electron transfer due to the presence of rGO. A possible mechanism was proposed for catalytic reduction of 4-nitrophenol over Cu2O/Cu-MOF/rGO. © 2019...