Yazar "Akcay, Mehmet" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    Benzylation of benzene and toluene with benzylchloride over clay-based acid catalysts
    (Mrs Pushpa Agarwal, 2006) Durap, Feyyaz; Akcay, Mehmet; Yurdakoc, Kadir
    The pillared clay catalysts were calcined after in corporation of metal polycation ions with exchangeable cations and water. Friedel-Crafts alkylations of aromatic hydrocarbons were carried out in the presence of clay catalysts originating from bentonite. In these reactions, it has been found that pillared clays have excellent catalytic activity. It was found that iron pillared clay (Fe-PILC) was the more efficient catalyst producing quantitative conversion with greatly reduced amounts of catalysts in short reaction period. Their efficiency is attributed to the higher Fe3+, Cr3+ and Al3+ contents in the catalysts and pillaring effect. The clays have both Bronsted and Lewis acidities which were determined by pyridine adsorption-desorption and in situ FTIR technique.
  • [ X ]
    Öğe
    The equilibrium and kinetics studies of flurbiprofen adsorption onto tetrabutylammonium montmorillonite (TBAM)
    (Elsevier, 2009) Akcay, Guelten; Kilinc, Ersin; Akcay, Mehmet
    In this study, the adsorption of flurbiprofen (FBP, is a non-steroidal anti-inflammatory drug) on tetrabutylammonium (TBA)-montmorillonite (TBAM) was studied. The adsorption kinetics was interpreted using pseudo-first-order kinetic model and pseudo-second-order kinetic model. The pseudo-second-order model provides the best correlation with the experimental data ofTBAM adsorption. The adsorption data could be fitted with Freundlich and Dubinin-Radushkevich equation to find the characteristic parameters of each model. The adsorption energy, E and adsorption capacity (q(m)) for organic compound adsorbing on organo montmorillonite were estimated using the Dubinin-Radushkevich (D-R) equation. From DR isotherm, it was also determined that the type of adsorption can be considered as physical adsorption mechanism. Thermodynamic parameters (Delta g(a)=-1.897 and -3.456 kJ/mol, Delta h(a)=-28.722 and -30.948 kJ/mol, Delta s(a)=-0.0964 and -0.0989 kJ/mol K for 298 and 313 K, respectively) were calculated by a new approximate from the adsorption isotherms of FBP on organo montmorillonite. The first order and second order coefficients (K-1ads = 2.50 and 14.30 mmol/g min, K-2ads = 0.0130 and 0.03120 g min/mu mol, respectively) were obtained at 298 and 313 K, respectively. (C) 2008 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    Preparation and characterization of Cr- and Fe-pillared bentonites by using CrCl3, FeCl3, Cr(acaC)3 and Fe(acac)3 as precursors
    (Elsevier, 2008) Yurdakoc, Mueruevvet; Akcay, Mehmet; Tonbul, Yalcin; Ok, Fatih; Yurdakoc, Kadir
    Four pillared bentonites (Cr-PILB, Cr(acaC)(3)-PILB, Fe-PILB and Fe(acaC)(3)-PILB were prepared and characterized by X-ray diffraction (XRD), nitrogen sorption measurements and thermogravimetric (TG) analysis. The surface acidities of the samples and their structures were also investigated in the gas phase adsorption data of pyridine by the aid of FT-IR spectroscopic techniques. The XRD data and FT-IR spectra of the samples reflected mainly the structure of bentonite. The nitrogen adsorption-desorption isotherms of the samples were Type II shaped and showed in general mesoporous structures with pore openings of 4 nm. Two steps mass losses were observed in the TGA thermograms of B, Cr-PILB and Fe-PILB, while three steps mass losses were detected in the case of Cr(acaC)(3)-PILB and Fe(acaC)(3)-PILB. IR study by the adsorption of pyridine on the samples showed both Lewis and Bronsted acid sites on their surfaces. (C) 2007 Elsevier Inc. All rights reserved.