Xn:Harmful;12190-71-5Relevant articles and documents
Mesoporous carbon supported platinum nanocatalyst: Application for hydrogen production by HI decomposition reaction in S-I cycle
Tyagi, Deepak,Varma, Salil,Bharadwaj, Shyamala R.
, p. 2177 - 2184 (2017)
Platinum supported on carbon as a catalyst is widely reported and have a wide range of applications ranging from fuel cell application to hydrogenation reactions, where structure and properties of carbon support play an important role in the functioning of the catalyst. Mesoporous carbon supported platinum nanocatalyst was synthesized by hard templating route using mesoporous silica as template. The catalyst prepared has been characterized by X-ray diffraction, Raman, SEM, TEM, XPS and BET surface area. This catalyst has been employed for liquid phase HI decomposition reaction of sulfur iodine thermochemical cycle for production of hydrogen. The catalyst was evaluated for its activity for HI decomposition reaction and stability in the reaction environment. From present study we conclude that Pt supported on mesoporous carbon is a suitable and stable catalyst for liquid phase HI decomposition reaction.
Ashley, S. E.,West, W.
, p. 308 - 308 (1931)
Lamb,Bray,Geldard
, p. 1636 - 1636 (1920)
Liebhafsky, H. A.
, p. 3499 - 3499 (1932)
Chlorite-Iodide Reaction: A Versatile System for the Study of Nonlinear Dynamical Behavior
Kepper, Patrick De,Boissonade, Jacques,Epstein, Irving R.
, p. 6525 - 6536 (1990)
The autocatalytic reaction between chlorite and iodide ions exhibits a remarkable range of dynamical behavior.In a stirred tank reactor it shows bistability between steady states and between a steady and an oscillatory state.It forms the core of a large f
Francis, A. W.
, p. 655 - 655 (1926)
Rosenthaler
, p. 219 - 222 (1922)
The Oscillatory Briggs-Rauscher Reaction. 1. Examination of Subsystems
Furrow, Stanley D.,Noyes, Richard M.
, p. 38 - 42 (1982)
In acidic aqueous solution at 25 deg C, only slow or nonexistent reaction is observed for any two of three species iodate ion, hydrogen peroxide, and manganous ion.However, if all three species are present, 0.002 M Mn2+ catalyzes the iodate oxidation of peroxide at a rate almost 1000 times that in the absence of a catalyst! This remarkable observation, which has already been reported by Cooke, can be explained by postulating that the radical oxidant *IO2 is very sluggish at abstracting hydrogen atoms from the species like H2O2 but can oxidize Mn2+ by electron transfer.A detailed mechanism has been proposed that models semiquantitatively not only the manganous catalyzed iodate oxidation of peroxide but also the simultaneous induced disproportionation of the peroxide and the fact that the concentration of elementary iodine does not increase to a limiting value but rises to a maximum and then decreases toward a small value.Despite this single extremum, the subsystem does not exhibit oscillatory behavior.
Synthesis and Characterization of 2-Pyridinylmethylene-2-quinolyl Hydrazone Cobalt(III) Complexes. Reactivity Trends and Solvent Effect on the Initial and Transition States of Base Catalyzed Hydrolysis
Mohamad, Ahmad Desoky M.
, p. 1575 - 1595 (2017)
The complexes of pyridine-2-aldehyde-2-quinolylhydrazone Co(III) nitrate [Co(paqh)2](NO3)2, methyl-2-pyridylketone-2-quinolinhyrazone Co(III) nitrate [Co(mpkqh)2](NO3)2, and phenyl-2-pyridylketon-2-quinolinhyrazone Co(III) nitrate [Co(ppkqh)2](NO3)2 were prepared and characterized. Solubilities of Co(III)–hydrazone complexes were measured. Transfer chemical potentials were calculated from the measured solubilities of the Co(III) complexes in aqueous methanol mixtures at 25?°C. The reactivity trends in the transfer chemical potentials are discussed in terms of the nature of the bonded ligands. Kinetics of the base hydrolysis of Co(III)–hydrazone complexes in the aqueous methanol mixtures have been studied at 25?°C, and follow the rate law kobs?=?k2[OH?]. The solvent effects on the reactivity trends of Co(III) complexes are analyzed into initial state (is) and transition states (ts) components. The reaction rates are reduced by the increase of methanol content. The destabilization of the transition state is remarkable compared to the initial state in the aqueous methanol mixtures. The initial state is more hydrophobic in nature than the transition state for Co(III) complex reactions.
Kinetics of the Oxidation of Substrate Ligands by Transition-metal Cations
Nazar, Abdul Fattah M.,Wells, Cecil F.
, p. 801 - 812 (1985)
The kinetics of the oxidation of iodide ions by CeaqIV have been investigated.The reaction is found to be first order in each of IV>, and , in contrast to the oxidation of Br(1-) by CeaqIV, which is second order in both and .Nevertheless, the direct order of one in found for the CeIV + I(1-) reaction can only be interpreted by assuming the involvement of intermediate Ce(4+) - I(1-) complexes.The second-order rate constant for the oxidation of I(1-) by CoaqIII is shown to vary with ionic strength, so the entalphy ΔH* and entropy ΔS* of activation have been determined in conditions where the rate is invariant with ionic strength.These values for ΔH* and ΔS* are compared with the values for other substrates.The oxidation of iodide ions is discussed in relation to a general mechanism for the oxidation of substrate ligands by aquatransition-metal cations.
Luther, R.,Rutter, T. F.
, p. 521 - 522 (1907)
Kruisheer, C. I.
, p. 196 - 197 (1932)
Smith, D. F.,Mayer, J. E.
, p. 75 - 83 (1924)
On-site detection of phosgene agents by surface-enhanced Raman spectroscopy coupled with a chemical transformation approach
Gao, Haiyue,Wu, Jianfeng,Zhu, Yingjie,Guo, Lei,Xie, Jianwei
, p. 233 - 239 (2016)
Phosgene and its analogs are greatly harmful to the public health, environmental safety and homeland security as widely used industrial substances with extremely high toxicity. In order to rapidly evaluate the emergency risk caused by these chemicals, a new highly sensitive method based on surface-enhanced Raman spectroscopy (SERS) technique for measurement of phosgene agents was developed for the first time. Coupled with a chemical transformation approach, the highly toxic phosgene was conveniently converted to a SERS-sensitive probe, i.e. iodine (I2), with low toxicity or non-toxicity. The characteristic SERS peak in 459 cm-1 was used for quantitation and was presumed as a formation of triiodide anion (I3-), which was induced in an iodide (I-)-aggregation Au NPs system. The total measurement can be completed in ~20 min with the limits of detection of ~60 μg/l (phosgene) and ~30 μg/l (diphosgene), respectively, on a portable Raman spectrometer. This work is the first report of SERS measurement on phosgene and diphosgene in a quantitative level. This method is expected to meet the requirements of on-site detection of phosgene agents, promote emergency responses and raise more opportunities for the portable SERS applications. A sensitive surface-enhanced Raman spectroscopy method for measurement of phosgene agents with a chemical transformation approach was reported for the first time. With the transformed product iodine, a more stable triiodide anion was formed in an iodide-aggregated Au nanoparticles system appeared as a characteristic ultraviolet-visible absorption peak at 352 nm and a surface-enhanced Raman spectroscopy peak of 459 cm-1. Three phosgene agents exhibit different reaction rates.
Juan, Julian de,Smith, Ian W. M.
, (1985)
Edgar, G.
, p. 2369 - 2377 (1916)
Experimental and modeling study of oscillations in the chlorine dioxide-iodine-malonic acid reaction
Lengyel, István,Rábai, Gyula,Epstein, Irving R.
, p. 9104 - 9110 (1990)
At pH 0.5-5.0, a closed system containing an aqueous mixture of chlorine dioxide, iodine, and a species such as malonic acid (MA) or ethyl acetoacetate, which reacts with iodine to produce iodide, shows periodic changes in the light absorbance of I3-. This behavior can be modeled by a simple scheme consisting of three component reactions: (1) the reaction between MA and iodine, which serves as a continuous source of I-; (2) the reaction between ClO2? and I-, which acts as a source of ClO2-; and (3) the self-inhibited reaction of chlorite and iodide that kinetically regulates the system. The fast component reaction between chlorine dioxide and iodide ion was studied by stopped-flow spectrophotometry. The rate law is -[ClO2?]/df = 6 × 103 (M-2 s-1)[ClO2?][I-]. A two-variable model obtained from the empirical rate laws of the three component reactions gives a good description of the dynamics of the system. The oscillatory behavior results not from autocatalysis but from the self-inhibitory character of the chlorite-iodide reaction.
Amis, E. S.,Potts, J. E.
, p. 2883 - 2888 (1941)
Weak acids enhance halogen activation on atmospheric waters surfaces
Hayase, Sayaka,Yabushita, Akihiro,Kawasaki, Masahiro,Enami, Shinichi,Hoffmann, Michael R.,Colussi, Agustin J.
, p. 4935 - 4940 (2011)
We report that rates of I2(g) emissions, measured via cavity ring-down spectroscopy, during the heterogeneous ozonation of interfacial iodide: I-(surface, s) + O3(g) + H+(s) →→ I2(g), are enhanced several-fold, whereas those of IO · (g) are unaffected, by the presence of undissociated alkanoic acids on water. The amphiphilic weak carboxylic acids appear to promote I2(g) emissions by supplying the requisite interfacial protons H+(s) more efficiently than water itself, at pH values representative of submicrometer marine aerosol particles. We infer that the organic acids coating aerosol particles ejected from oceans topmost films should enhance I2(g) production in marine boundary layers.
Bates, J. R.,Lavin, G. I.
, p. 81 - 81 (1933)
Spontaneous Formation of Cellular Chemical System that Sustains Itself far from Thermodynamic Equilibrium
Maselko, Jerzy,Strizhak, Peter
, p. 4937 - 4939 (2004)
We report the observation of the spontaneous formation of a cellular structure in a simple inorganic system. The system is obtained by immersing a pellet of calcium and copper chlorides in an alkali solution containing sodium carbonate, sodium iodide, and hydrogen peroxide. The system produces a cell surrounded by a semipermeable membrane. Reactants diffuse and react inside the cell with copper ions serving as catalyst. The products diffuse out of the cell. The system sustains itself far from thermodynamic equilibrium.
Liebhafsky, H. A.
, p. 1792 - 1792 (1932)
Chaumeil, A.
, p. 194 - 194 (1903)
Lewis, B.
, p. 493 - 493 (1927)
Masson, I.,Argument, C.
, (1938)
Synthesis, structural and magnetic characterizations of a dinuclear copper(II) complex with an (N,S,O) donor ligand: Catecholase and phenoxazinone synthase activities
Ghosh, Ayon Kanti,Ali, Anzar,Singh, Yogesh,Purohit, Chandra Shekhar,Ghosh, Rajarshi
, p. 156 - 163 (2018/02/20)
A new dinuclear Cu(II) complex (1) was synthesized and crystallographically characterized. Each of the Cu(II) centres has penta coordination and been found to adopt square pyramidal geometry. Variable temperature magnetic measurements showed that there is weak ferromagnetic interaction between the Cu(II) centres in 1. 1 shows catecholase as well as phenoxazinone synthase activities in different solvents. The turn over numbers for the catecholase activity were 4.02 × 103 h?1 (MeOH) and 9.57 × 103 h?1 (MeCN), and that of phenoxazinone synthase activity were 1.065 × 103 h?1 (MeOH), 2.13 × 102 h?1 (MeCN) and 2.844 × 103 h?1 (DCM).
