Browsing by Author "Odebunmi, E.O."

Now showing 1 - 8 of 8
  • Item
    Kinetic and thermodynamic studies of glucose oxidase catalysed oxidation reaction of glucose
    (World Bank Assisted Nationally Coordinated Research Programmes (NCRP), National Agricultural Research Programme (NARP)-University of Port Harcourt, 2007-12-14) Odebunmi, E.O.; Owalude, S.O.
    The kinetics of oxidation of D-glucose catalysed by the enzyme glucose oxidase has been studied over a wide range of experimental conditions. The reaction velocities increased with increase in the concentrations of the glucose oxidase and glucose, as well as increase in temperature and ionic strength of the solution. The reaction velocity initially increased with increase in pH, reaching a maximum at pH 6.5 and then decreased with further increase in pH. The reaction exhibited saturation kinetics and experimental data were analysed using the Michaelis-Menten equation. Arrhenius activation energy and thermodynamic activation parameters were measured and are reported. The large negative value of entropy of activation, ΔS≠, -148.8 JK-1mol-1, and positive value of the enthalpy of activation, ΔH≠, 26.3 kJmol-1, give further support to the proposed mechanism. The results are interpreted in terms of a mechanism involving both an oxidative half reaction and a reductive half reaction.
  • Item
    Kinetics and Mechanism of Oxidation of Some Simple Reducing Sugars by Permanganate Ion in Alkaline Medium
    (Iranian Chemical Society, 2008-12-04) Odebunmi, E.O.; Owalude, S.O.
    The kinetics of oxidation of glucose, galactose, fructose, maltose and sucrose by alkaline permanganate anion has been studied. The reactions studied spectrophotometrically over a wide range of experimental conditions show that the rate of the reactions is enhanced by increase in pH, ionic strength, and temperature as well as the reactant concentrations. The mechanism has been proposed to proceed via the formation of enediol intermediate complexes and the order of reactivities of the sugars is fructose > glucose ≈ galactose > maltose > sucrose. The activation parameters were evaluated and lend further support to the proposed mechanism.
  • Item
    Kinetics and mechanism of oxidation of sugars by chromium (vi) in perchloric acid medium
    (Chemical Society of Nigeria, 2005-05-03) Odebunmi, E.O.
    Kinetic data for the oxidation of D-glucose, fructose, maltose and sucrose by chromium (VI) in perchloric acid medium are reported The results of the reactions studied spectrophotometrically over a wide range of experimental conditions show that the rate· of the reaction is enhanced by increase in pH, ionic strength and concentrations of the sugars. The reactions are first-order with respect to both the sugars and Cr(VI) white the order with respect to [H] is complex. The order of reactivities of the sugars is fructose > maltose> glucose> sucrose. Formation of free radical intermediate complex was demonstrated and the kinetic results indicate the formation of a 1:1 intermediate complex between Cr(VI) and the sugars. The activation parameters have been evaluated and lend further support to the proposed mechanism.
  • Item
    Kinetics of oxidation of D-Arabinose and D-Xylose by Vanadium (V) in the presence of Manganese II as homogeneous catalyst
    (Chilean Chemical Society, 2010-02-10) Odebunmi, E.O.; Ogunlaja, A.S.; Owalude, S. O.
    Kinetics of oxidation of D-arabinose and D-Xylose by acidic solution of Vanadium (V) ions in the presence of manganese (II) has been reported. First-order dependence of the reaction rate was observed on [sugars] and [H+] at low concentrations throughout the oxidation reaction and a zeroth-order dependence on [sugar] and [H+] was observed at high concentrations. First-order kinetics with respect to [Mn (II)] was also observed throughout the oxidation for both sugars. The effect of Cl− concentration was found to be negligible. The reaction rates increases with the ionic strength of the medium. Various activation parameters were evaluated and provide further support to the proposed mechanism. Formic acid was reported as one of the oxidation products of the sugars.
  • Item
    A new heterobimetallic ruthenium(II) complex: synthesis, spectral studies and catalytic activity potential in the transfer hydrogenation of ketones
    (Chemical Society of Nigeria, 2019-06-07) Owalude, S. O.; Tella, A.C.; Eke, U. B.; Odebunmi, E.O.
    A new heterobimetallic ruthenium(II) complex with general formula [Ru(NCCH3)2(P(OMe)2Ph)2- (dppf)][BF4]2. {NCCH3 = acetonitrile P(OMe)2Ph = dimethylphenylphosphonite, dppf = 1,1’-bis-{diphenylphosphino}ferrocene} was synthesized from a one pot reaction of [Ru(COD)-(NCCH3)4][BF4]2, dimethylphenylphosphonite and 1,1’-bis{diphenylphosphino}ferroc-ene in dichloromethane under continuous stirring. The complex was characterized by NMR (31P{1H}, 1H and 13C), vibrational spectroscopy (FTIR) and elemental analysis. Catalytic performance of the complex in the transfer hydrogenation of cyclohexanone was investigated. An 80% conversion was achieved at a substrate to catalyst ratio of 1250 with 98% selectivity.
  • Item
    Photocatalytic degradation of alizarin red dye in aqueous solution using titania-nickel and titania-cobalt nanocomposites
    (Obafemi Awolowo University, Ife, Nigeria, 2018-03-15) Odeyemi, O.T.; Owalude, S.O.; Odebunmi, E.O.
    Titanium dioxide (TiO ) was prepared by Sol-gel method which involved hydrolysis of Titanium trichloride (TiCl3) with concentrated hydrochloric acid and oxidation by hydrogen peroxide. Doping of the TiO2 was effected at 10% Ni-TiO2 and 10% Co-TiO2 using aqueous solutions of nickel nitrate and cobalt nitrate respectively. Characterization by X-ray Diffraction Crystallography (XRD) and Scanning Electron Microscopy (SEM) showed that the surface area and crystallinity of TiO2 increased through doping. The XRD and SEM data confirmed the observed increase in the photocatalytic activities of the doped versus the undoped TiO2 photocatalysts. Photocatalytic activities of both the doped and undoped TiO was investigated on the 2 o photodegradation of Alizarin red dye. With a constant dye concentration of 25 ppm and temperature of 40 C, it was observed that for all varying concentrations except 0.25 g/l of catalyst at 240 mins, the percentage degradation was of the order TiO < Co-TiO < Ni-TiO . At the 0.25 g/l concentration of catalyst at 240 mins, 2 2 2 the photocatalytic activities of the Ni-TiO and Co-TiO were observed respectively to be about 9 times and 12 2 2 times that of the TiO .
  • Item
    Synthesis of new ruthenium(II) complexes containing isocyanide and labile nitrile ligands
    (Ahmadu Bello University, Zaria, Nigeria, 2017-10-30) Owalude, S. O.; Tella, A.C.; Eke, U. B.; Odebunmi, E.O.
    A new ruthenium(II) complex containing both acetonitrile and propionitrile moieties as coordinating ligands has been prepared. The treatment of the polymer [{RuCl2(COD)}x], (COD = cycloocta-1,5-diene) (1) with a mixture of acetonitrile and propionitrile under reflux produced a new precursor [RuCl2(COD)(NCCH3)(CH3CH2CN)] (2). Also the compound [RuCl2L4] (3) (L = 2,6-dimethylphenylisocyanide) was prepared through a ligand exchange of a derivative of 1, [RuCl2(COD)(NCCH3)2] (4), with 2,6-dimethylphenylisocyanide. The two compounds were characterized by elemental analyses, IR and NMR (1H and 13C) measurements. The ruthenium in both compounds has distorted octahedral coordination geometry.
  • Item
    Synthesis, characterization and biological activity screening of metal (II) complexes of some nitrogen and dioxygen donor ligands
    (Ahmadu Bello University, Zaria, Nigeria, 2016-05-30) Owalude, S. O.; Tella, A.C.; Duntoye, M.R.; Adimula, V.O.; Eke, U. B.; Odebunmi, E.O.
    A series of Ni(II) and Cu(II) complexes of Schiff base ligands derived from 4-aminobenzoic acid, 2- aminophenol, salicylaldehyde and 1H-indole-2,3-dione have been synthesized and characterized by elemental analysis, FT-IR, UV-vis and NMR spectroscopic analyses. Elemental analysis data were in agreement with a metal:ligand ratio of 1:1 for the complexes formed with HL1, HL3 and HL4 in a tetrahedral geometry fashion while those with HL2 results in complexes with metal:ligand ratio of 1:2 in octahedral arrangement. The antimicrobial activity of the Schiff base ligands and their metal complexes were investigated on the strains of gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella typhi) as well as on the fungi strains (Candida albicans, Aspergillus niger, Rhizopus stolonifer and Penicillium notatum) using disc diffusion method. The results showed that the zones of inhibition of the metal complexes for both species were higher than that of the Schiff base ligands. This indicates that the metal complexes can be applied in drug design to control bacterial and fungal diseases.