Kinetics and Mechanism of Ruthenium(III)-Catalyzed Oxidation of L-citrulline by Hexachloroplatinate(IV) in Perchloric Acid
Ahmed Fawzy,
Ishaq A. Zaafarany,
Ismail I. Althagafi,
Hatem M. Altass,
Moataz H. Morad,
Fahd A. Tirkistani
Issue:
Volume 4, Issue 5, October 2016
Pages:
53-60
Received:
29 August 2016
Accepted:
5 September 2016
Published:
24 September 2016
Abstract: Oxidation kinetics of L-citrulline (Cit) by hexachloroplatinate(IV) (HCP) was studied spectrophotometrically in perchloric acid solutions in the presence of ruthenium(III) catalyst at a constant ionic strength of 1.8 mol dm-3 and at 20°C. The reaction rate was very slow in the absence of the catalyst. The reaction showed first order kinetics in both [HCP] and [Ru(III)] and less than unit order with respect to both [Cit] and [H+]. Increasing ionic strength and dielectric constant were found to increase the oxidation rate. Both spectral and kinetic evidences revealed formation of an intermediate complex between L-citrulline and ruthenium(III) prior to the rate-determining step. The complex reacts with the oxidant (HCP) by an inner-sphere mechanism leading to decomposition of the complex in the rate-determining step to give rise to the final oxidation products of L-citrulline which were identified by both spectroscopic and chemical tools as 4-(carbamoylamino) butyraldehyde, ammonia and carbon dioxide. The rate-law expression for the catalyzed reaction was deduced. The reaction constants involved in the different steps of the reaction mechanism have been evaluated. The activation parameters of the second order rate constant have been evaluated and discussed.
Abstract: Oxidation kinetics of L-citrulline (Cit) by hexachloroplatinate(IV) (HCP) was studied spectrophotometrically in perchloric acid solutions in the presence of ruthenium(III) catalyst at a constant ionic strength of 1.8 mol dm-3 and at 20°C. The reaction rate was very slow in the absence of the catalyst. The reaction showed first order kinetics in bot...
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Synthesis and Characterization of an Ionic Liquid Enhanced High Oil Absorption Resin of P (BMIm-MMA-BA) and Its Oil Absorption Performance
Fathelrahman Mohammed Soliman,
Wu Yang,
Hao Guo,
Wen Yao,
Mahgoub Ibrahim Shinger,
Ahmed Mahmoud Idris,
Emtenan Suliman Hassan,
Ali Mahmoud Alamin
Issue:
Volume 4, Issue 5, October 2016
Pages:
61-68
Received:
27 August 2016
Accepted:
21 September 2016
Published:
11 October 2016
Abstract: A novel oil highly absorptive resin was prepared by a suspension polymerization using 1-butyl -3- (2- methacryl) ethyl imidazolium hexafluorophosphate (BMIm)PF6-, methyl methacrylate (MMA), and butylacrylate (BA) as monomers, azobisisobutyronitrile as initiator, N, N methylenebis (acryl amide) (MBA) as crosslinking agent and polyvinyl alcohol (PVA) as dispersant and characterized by Fourier-transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). The effects of different polymerization technological parameters, such as the mass ratios of the monomers, the addition amounts of the initiator, the cross-linker and the dispersant, the polymerization temperature and time, on the oil absorbency of the high oil absorption resin P (BMIm-MMA-BA) copolymer were examined in detail. Under the optimal condition, the oil absorbency was about 25.6 g/g for benzene, 22.6 g/g for xylene, 32.3g/g for chloroform, and 30 g/g for carbon tetrachloride, respectively. The kinetic investigation indicated the oil absorption obeyed the pseudo-first-order kinetic equation.
Abstract: A novel oil highly absorptive resin was prepared by a suspension polymerization using 1-butyl -3- (2- methacryl) ethyl imidazolium hexafluorophosphate (BMIm)PF6-, methyl methacrylate (MMA), and butylacrylate (BA) as monomers, azobisisobutyronitrile as initiator, N, N methylenebis (acryl amide) (MBA) as crosslinking agent and polyvinyl alcohol (PVA)...
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