oxidation of ethylene to ethylene oxide over silver catalyst and selenium modified catalyst has been studied by continuous flow and pulse techniques over the temperature range of 230-280 °c. the results are discussed in terms of reaction mechanisms proposed by others, rejecting mechanisms which involve peroxide formation. it has been shown that not only selectivity towards ethylene oxide produc...

fischer-tropsch synthesis is a promising route for production of light olefins via co hydrogenation over transition metals. co is one of the most active metals for fischer-tropsch synthesis. some different variables such as preparation parameters and operational factors can strongly affect the selectivity of fischer-tropsch synthesis toward the special products. in the case of preparation varia...

nanometric carbid silicon (sic) supported monometallic and bimetallic catalysts containing fe, co, ni transition metals were prepared by wet impregnation method. multiwall carbon nanotubes (mwcnts) were synthesized over the prepared catalysts from catalytic decomposition of acetylene at 850°c by thermal chemical vapor deposition (tcvd) technique. the synthesized nanomaterials (catalysts and cnt...

Zincian georgeite, an amorphous copper-zinc hydroxycarbonate, has been prepared by co-precipitation using acetate salts and ammonium carbonate. Incorporation of zinc into the georgeite phase and mild ageing conditions inhibits crystallisation into zincian malachite or aurichalcite. This zincian georgeite precursor was used to prepare a Cu/ZnO catalyst, which exhibits a superior performance to a...

The non-sulfided Ni-PTA/Al2O3 catalyst was developed to produce green diesel from the hydroprocessing of Jatropha oil. The Ni-PTA/Al2O3 catalyst was prepared by one-pot synthesis of Ni/Al2O3 with the co-precipitation method and then impregnanting Ni/Al2O3 with PTA solution. The catalysts were characterized with BET, SEM-EDX, TEM, XRD, XPS, TGA and NH3-TPD. The Ni and W species of the Ni-PTA/Al2...

We show that the activity and selectivity of Cu catalyst can be promoted by a Zr-based metal-organic framework (MOF), Zr6O4(OH)4(BDC)6 (BDC = 1,4-benzenedicarboxylate), UiO-66, to have a strong interaction with Zr oxide [Zr6O4(OH)4(-CO2)12] secondary building units (SBUs) of the MOF for CO2 hydrogenation to methanol. These interesting features are achieved by a catalyst composed of 18 nm single...

In this work, the WGS performance of a conventional Ni/CeO2 bulk catalyst is compared to that of a carbon-supported Ni-CeO2 catalyst. The carbon-supported sample resulted to be much more active than the bulk one. The higher activity of the Ni-CeO2/C catalyst is associated to its oxygen storage capacity, a parameter that strongly influences the WGS behavior. The stability of the carbon-supported...

Heterogeneous catalysis and their application in industrial-scale organic synthesis of fine chemicals are greatly facilitated by catalysis and further on by catalyst recovery and recycles to fits most “principles of green chemistry. In acid media, terpenoids generally undergoes various transformations. The terpenoid transformations include various liquid Bronsted and Lewis Acids, Acid clays, He...

‎The global FOM and GMRES algorithms are among the effective‎ ‎methods to solve Sylvester matrix equations‎. ‎In this paper‎, ‎we‎ ‎study these algorithms in the case that the coefficient matrices‎ ‎are real symmetric (real symmetric positive definite) and extract‎ ‎two CG-type algorithms for solving generalized Sylvester matrix‎ ‎equations‎. ‎The proposed methods are iterative projection metho...

We classify the paracontact Riemannian manifolds that their Riemannian curvature satisfies in the certain condition and we show that this classification is hold for the special cases semi-symmetric and locally symmetric spaces. Finally we study paracontact Riemannian manifolds satisfying R(X, ξ).S = 0, where S is the Ricci tensor.