Journal of Molecular Catalysis A Chemical (J MOL CATAL A-CHEM)

Publications in this journal

• Article: Silica Gel Supported Polyamine: A Versatile Catalyst for One Pot Synthesis of 2-Amino-4H- Chromene Derivatives

  R.L. Magar, P.B. Thorat, V.B. Jadhav, S.U. Tekale, S.A. Dake, B.R. Patil, R.P. Pawar
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  ABSTRACT: An efficient synthesis of 2-amino-4H-chromene derivatives is achieved via one pot three component coupling reaction of aromatic aldehyde, active methylene compound and activated phenol in presence of silica gel supported polyamine heterogeneous catalyst. The catalyst is easily prepared, highly stable, simple to handle and recycled for several times without significant loss of activity.
  Journal of Molecular Catalysis A Chemical 04/2013;
• Article: Effect of gallium as an additive in hydrodesulfurization WS2/γ-Al2O3 catalysts

  J.N. Díaz de León, M. Picquart, M. Villarroel, M. Vrinat, F.J. Gil Llambias, F. Murrieta, J.A. de los Reyes
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  ABSTRACT: The effect of gallium in W/Ga(x)–�-Al2O3 catalysts was investigated in the hydrodesulfurization of dibenzothiophene. The g�-Al2O3 carrier was modified by the gallium addition prior to W impregnation and further calcination at 723 K. An electrophoretic study was carried out on the calcined Ga samples at 0, 0.29, 0.55, 0.84, 1.09, 1.43, 1.71 and 2.22 wt.% of Ga and it indicated that Ga addition affected significantly the surface of alumina. The presence of at least two gallium species was proposed, at low gallium content GaAl2O4 species decreased the isoelectric point (IEP) and probably the formation of Ga2O3 at higher contents increased again the IEP. Raman spectroscopy showed that the gallium incorporation had a strong effect in the formation of WOx species at the surface of catalysts. The highest amount of irregular WOx particles calculated by the Raman (O W O+W O)/W–O–W band intensities ratio was found on the W/Ga(1.09)–�-Al2O3 catalyst. The presence of gallium induced higher activity on the dibenzothiophene hydrodesulfurization reaction in all catalysts tested. The highest Raman ratio and the highest activity were found for the W/Ga(1.09)–�-Al2O3 catalyst, suggesting that better dispersed W species could be responsible for the highest HDS activities.
  Journal of Molecular Catalysis A Chemical 04/2013; 323:1-6.
• Article: Interaction of hydrogen with Cu-Zn mixed oxide model methanol synthesis catalyst.

  A.A. Khassin, H. Jobic, G.A. Filonenko, E.V. Dokuchits, A.V. Khasin, T.P. Minyukova, N.V. Shtertser, L.M. Plyasova, T.M. Yurieva
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  ABSTRACT: Interaction of hydrogen with model Cu-Zn methanol synthesis catalyst prepared by decomposition of mixed hydroxicarbonate is studied by inelastic neutron scattering, in-situ FTIR/MS, and thermal analysis. Reduced (Cu0.08,Zn0.92)O mixed oxide accumulates 6H/Cu, mainly as hydride, hydroxyl and formate species. The reduction of copper in the (Cu,Zn)O mixed oxide occurs via a reversible redox interaction with H2 and absorption of protons as OH−-groups with ν = 3250 cm−1 and δ ≈ 1430-1480 cm−1. Kinetic and thermodynamic parameters of this process are evaluated. The weight loss during the reduction is due to the decomposition of the residual carbonate groups to CO2 via formate intermediates, which occurs in the presence of hydrogen. Exposure of (Cu,Zn)O to air prior to the reduction strongly affects the kinetic parameters of the reduction process.
  Journal of Molecular Catalysis A Chemical 03/2013;
• Article: Polymorphic phase transformation of Degussa P25 TiO2 by the chelation of Diaminopyridine on TiO62− octahedron: Correlation of anatase to rutile phase ratio on the photocatalytic activity

  K. Eraiah Rajashekhar, L. Gomathi Devi
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  ABSTRACT: A series of nitrogen-doped Degussa P25 photocatalysts were synthesized successfully by grinding and calcination method using 2, 6-Diaminopyridine (DAP) as a nitrogen precursor. The prepared samples were characterized by various analytical methods. The phase contents of anatase and rutile in the Degussa P25 powders have been altered by simply changing the proportion of DAP. A mechanism involving chelated DAP molecule on TiO62− octahedron is discussed. The enhanced activity is attributed to synergistic effect in the two phase solid material. Due to the low activation barrier, the effective inter particle electron transfer between the two polymorphs is quite efficient only when they are in close proximity with similar crystallite sizes. The transfer of electrons from the rutile phase to lattice/electron trapping sites of anatase and also to the Ti3+-Vo defect level created by the dopant favors effective charge separation and enhance the photocatalytic activity under solar illumination.
  Journal of Molecular Catalysis A Chemical 03/2013;
• Article: A biguanide/Pd-decorated SBA-15 hybrid nanocomposite: Synthesis, characterization and catalytic application

  A. Alizadeh, M.M. Khodaei, D. Kordestani, M. Beygzadeh
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  ABSTRACT: A stable palladium-decorated SBA-15 nanocomposite was simply fabricated through surface modification of SBA-15 with biguanide and subsequent metal/ligand coordination with Pd2+ from inexpensive commercially available starting materials and using standard laboratory techniques. The structure of this organic inorganic hybrid material was characterized by SEM, TEM, XRD, elemental analyzer, atomic absorption spectroscopy, N2 adsorption–desorption (BET), and FT-IR techniques. The catalytic performance of this novel heterogeneous catalyst was determined for the Suzuki cross-coupling and aerobic oxidation of benzyl alcohols. The composite exhibited an excellent catalytic activity and reuse ability of various recycles in air for the aforementioned organic transformations. TEM images of the recovered catalyst showed retained ordered mesostructure of SBA-15 with no damage in the periodic structure of the silicate framework and a good dispersion of in situ generated palladium nanoparticles within the SBA-15 structure.
  Journal of Molecular Catalysis A Chemical 03/2013; 372:167– 174.
• Article: Oxidation of phenol, styrene and methyl phenyl sulfide with H2O2 catalysed by dioxovanadium(V) and copper(II) complexes of 2-aminomethylbenzimidazole-based ligand encapsulated in zeolite-Y

  M.R. Maurya, A.K. Chandrakar, S. Chand
  Journal of Molecular Catalysis A Chemical 02/2013; 263(1-2):227-237.
• Article: Magnetic nanoparticle supported polyoxometalate: An efficient and reusable catalyst for solvent-free synthesis of �alfa-aminophosphonates

  H. Hamadi, M. Kooti, M. Afshari, Z. Ghiasifar, N. Adibpour
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  ABSTRACT: A new magnetically separable catalyst consisting of phosphotungstic acid (PTA) supported on imidazole functionalized silica coated cobalt ferrite nanoparticles was prepared. The synthesized catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The immobilized phosphotungstic acid was shown to be an efficient heterogeneous catalyst for the synthesis of �-aminophosphonates under solvent-free conditions at room temperature. The catalyst is readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.
  Journal of Molecular Catalysis A Chemical 02/2013; 373:25-29.
• Article: An efficient one-pot synthesis of polyhydroquinoline derivatives through the Hantzsch four component condensation

  James L. Donelson
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  ABSTRACT: A straightforward and general method has been developed for the synthesis of polyhydroquinolines derivatives by simply combining aldehyde, ethyl acetoacetate, dimedone, and ammonium acetate in the presence of a catalytic amount of scandium triflate. This method is very easy, rapid, and high yielding reaction for the synthesis of polyhydroquinolines.
  Journal of Molecular Catalysis A Chemical 02/2013; 256:309.
• Article: Mechanistic aspects for the direct oxidative esterification of aldehydes with alcohols over Pd catalyst: A computational study

  Xiaoqian Yao, Yanyan Diao, Xiaomin Liu, Yong-Wang Li, Kun Dong, Suojiang Zhang
  Journal of Molecular Catalysis A Chemical 02/2013; 358:166-175.
• Article: Pyrazole or tris(pyrazolyl)ethanol oxo-vanadium(IV) complexes as homogeneous or supported catalysts for oxidation of cyclohexane under mild conditions

  Telma F.S. Silva, Tatiana C.O. Mac Leod, Luísa M.D.R.S. Martins, M. Fátima C. Guedes da Silva, Marco Antonio Schiavon, Armando J.L. Pombeiro
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  ABSTRACT: The oxovanadium(IV) complexes [VO(acac)2(Hpz)]·HC(pz)3 1·HC(pz)3 (acac = acetylacetonate, Hpz = pyrazole, pz = pyrazolyl) and [VOCl2{HOCH2C(pz)3}] 2 were obtained from reaction of [VO(acac)2] with hydrotris(1-pyrazolyl)methane or of VCl3with 2,2,2-tris(1-pyrazolyl)ethanol. The compounds were characterized by elemental analysis, IR, Far-IR and EPR spectroscopies, FAB or ESI mass-spectrometry and, for 1, by single crystal X-ray diffraction analysis. 1 and 2 exhibit catalytic activity for the oxidation of cyclohexane to the cyclohexanol and cyclohexanone mixture in homogeneous system (TONs up to 1100) under mild conditions (NCMe, 24 h, room temperature) using benzoyl peroxide (BPO), tert-butyl hydroperoxide (TBHP), m-chloroperoxybenzoic acid (mCPBA), hydrogen peroxide or the urea-hydrogen peroxide adduct (UHP) as oxidants. 1 and 2 were also immobilized on a polydimethylsiloxane membrane (1-PDMS or 2-PDMS) and the systems acted as supported catalysts for the cyclohexane oxidation using the above oxidants (TONs up to 620). The best results were obtained with mCPBA or BPO as oxidant. The effects of various parameters, such as the amount of catalyst, nitric acid, reaction time, type of oxidant and oxidant-to-catalyst molar ratio, were investigated, for both homogeneous and supported systems.
  Journal of Molecular Catalysis A Chemical 02/2013; 367:52-60.
• Article: Supported monocationic copper(II) complexes obtained by coordination with dialkylphosphonate groups on styrene-divinylbenzene copolymer as catalysts for oxidation of organic compounds

  Viorica Parvulescu, Violeta Niculescu, Ramona Ene, Adriana Popa, Mihaela Mureseanu, Cristian D. Ene, Marius Andruh
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  ABSTRACT: New catalysts were synthesized by immobilization of neutral and monocationic copper complexes Cu(hfac)(2) (hfac(-) = hexafluoroacetylacetonato ligand) and [Cu(acac)(tmen)]NO3 (acac(-) = acetylacetonato ligand, tmen = N.N.N',N'-tetramethyl-ethylendiamine) on styrene-divinylbenzene copolymer functionalized with four different dialkyl phosphonate moieties typified by P-PO(OR)(2) (with R = -CH3, -C2H5, -(C3H7)-C-i, and -(C4H9)-C-n). The formation of P(O)(OR)(2) phosphonates groups has been confirmed by the FT-IR spectra. Thermogravimetric analysis results reveal that the thermal stability of polymer support depend on the functional group attached. The complexes were anchored by coordination interaction between the copper(II) ion and the phosphonate oxygen atom on each of the four functionalized supports and the strength of the P=O center dot center dot center dot Cun+ coordination interaction was influenced by the nature of the R group. The effect of functionalized supports on the structure and catalytic activity of Cu(hfac)(2) and [Cu(acac)(tmen)](+) mononuclear species was determined in oxidation of several organic compounds (anisole, cyclohexene, toluene, styrene, phenol) with hydrogen peroxide. The catalytic activity results show that the activity and selectivity of Cu(II) complexes depends on the equilibrium between steric factor and inductive electron-releasing effect. The best selectivity was obtained in oxidation of anisole, phenol and styrene for all the catalysts. The main products were for 2-methoxyphenol, catechol and benzaldehyde, respectively.
  Journal of Molecular Catalysis A Chemical 01/2013; 366:275-281.
• Article: Photoelectrocatalytic degradation of blistering agent sulphur mustard to non blistering substances using pPy/NiOBPC nanocomposite

  Pushpendra K Sharma, Garima Gupta, Anil K Nigam, Pratibha Pandey, Mannan Boopathi, Kumaran Ganesan, Beer Singh
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  ABSTRACT: In this study, we have explored a simple and new strategy to degrade the blistering agent sulfur mustard (HD) stockpiles into non blistering chemicals at ambient conditions by using an electrochemically prepared polypyrrole nickel octabutoxyphthalocyanine nanocomposite on platinum electrode (NiOBPC/pPy/Pt). Scanning electron microscopy indicated the presence of pPy–NiOBPC nanocomposite on NiOBPC/pPy/Pt and EDX confirmed the electrochemical incorporation of NiOBPC on pPy/Pt. The pPy/Pt and NiOBPC/pPy/Pt are also characterized electrochemically and then used for further studies. NiOBPC/pPy/Pt photoelectrocatalytically degraded sulfur mustard (100–0.0%) in 5 h. The degradation products identified by gas chromatography–mass spectrometry were non blistering chemicals (thiodiglycol, butyleneglycol and ethyleneglycol). Moreover, electrochemical parameters such as diffusion coefficient (9.8 × 10−7 cm2/s), heterogeneous rate constant (0.639 s−1), transfer coefficient (0.732) and the number of electron involved (1.0) in the HD reduction were deduced from the CV results of NiOBPC/pPy/Pt.
  Journal of Molecular Catalysis A Chemical 01/2013; 366:368–374.