14900-04-0Relevant academic research and scientific papers
Reaction Kinetics in a Microemulsion Medium IV. Hexacyanoferrate(III)-Iodide Reaction in Water/Aerosol-OT/Heptane Microemulsion and Mixed Solvents
Mukherjee, Kallol,Mukherjee, Dulal Chandra,Moulik, Satya Priya
, p. 1245 - 1253 (1997)
The kinetics of the reaction between [Fe(CN)6]3- and I- was studied in a W/O microemulsion (Water/AOT/Heptane at different [Water]/[Amphiphile] mole ratios) and in mixed water-organic media (water-formamide, water-ethylene glycol, and water-dioxane). The pseudo-first-order rate constants were observed to radically increase in microemulsion media with a [Water]/[AOT] mole ratio below 6. At a mole ratio of 5.4, the rate constant was found to be about 20-fold greater than that in water. At a constant mole ratio, the rate constant was witnessed to be independent of [AOT]. In all mixed media, the rate decreased with increasing proportion of the nonaqueous solvent. The ionic-strength effect on the reaction did not obey either the modified Bronsted-Bjerrum or Bronsted-Bjerrum-Pitzer relations in the studied nonaqueous media, except for ethylene glycol. This disagreement is very prominent in the studied W/O microemulsion medium at [Water]/[AOT] ω = 9.1. The activation parameters for the pseudo-first-order reaction in all of the studied media suggested distinct difference of the microemulsion from other solvents. A reasonable compensation between ΔH? and ΔS? i.e., the isokinetic effect, was observed.
Halogenated Peroxyl Radicals as Multi-Electron Oxidants: Pulse Radiolysis Study on the Reaction of Trichloromethyl Peroxyl Radicals with Iodide
Bonifacic, Marija,Schoeneich, Christian,Asmus, Klaus-Dieter
, p. 1117 - 1119 (1991)
CCl3OO radicals are shown to oxidize three equivalents of iodide ions to yield one I2 molecule (showing up as I3- in aqueous solution) and one I-radical atom (showing up as I2-radical anion per peroxyl unit; the mechanism is considered to proceed via a protonated CCl3OO-radical/I- adduct radical as the primary intermediate and subsequent nucleophilic (SN2) attack by a second iodide accompanied by electron localization in the hydroperoxide moiety leads to I2 and CCl3O-radical with the latter being responsible for the oxidation of the third iodide.
Sequential flow injection determination of iodate and periodate with spectrophotometric detection.
Ensafi, Ali A,Chamjangali, M Arab
, p. 2897 - 2903 (2003)
A flow injection (FI) system is described for the sequential determination of periodate and iodate based on their reaction with iodide at pH 3.5. Two sample plugs were injected into the same carrier stream sequentially. One injection is for the iodate determination and the other for the sum of iodate and periodate determination. For iodate determination, molybdate solution buffered at pH of 3.5 was used for selective masking of periodate. The influences of reagent concentrations were studied by a univariable method and the influence of FI manifolds was studied using univariable and simplex method. Periodate and iodate can be determined in the range of 0.050-5.0 and 0.050-10 microg/ml, respectively. The 3 sigma limit of detection was 0.030 and 0.050 microg/ml for periodate and iodate, respectively. The proposed method has been applied for the sequential determinations of periodate and iodate in water samples.
Effect of acetylacetone on morphology and crystalline structure of nanostructured TiO2 in titanium alkoxide aqueous solution system
Nakagawa, Keizo,Wang, Fumin,Murata, Yusuke,Adachi, Motonari
, p. 736 - 737 (2005)
Network structure of single-crystal-like TiO2 nanowires with anatase phase was synthesized at low temperature by the "oriented attachment" mechanism. The most important factor for synthesis of network structure of the TiO2 nanowires
Photolysis of triiodide studied by femtosecond pump-probe spectroscopy with emission detection
Gilch, Peter,Hartl, Ingmar,An, Qingrui,Zinth, Wolfgang
, p. 1647 - 1653 (2002)
The photodissociation of triiodide into diiodide and iodine in ethanol solution was studied by a novel femtosecond pump-probe technique. The dispersed emission of the triiodide sample was recorded as a function of the delay between a 407 nm pump pulse and
α-cyclodextrin-I3- host-guest complex in aqueous solution: Theoretical and experimental studies
Minns, Jason W.,Khan, Arshad
, p. 6421 - 6425 (2002)
UV-vis spectroscopic studies on aqueous solutions of iodine, potassium iodide, and α-cyclodextrin (αCD), (C6H10O5)6, suggest that a complex forms with the composition of αCD2I3-. Semiempirical quantum mechanical PM3 calculations suggest that two major host-guest isomer types exist for this complex. The most stable isomer has the I3- ion oriented almost parallel to the plane of one of the αCD molecules and sandwiched between two αCD molecules. The second sandwich isomer is less stable than the above isomer by about 5 kcal/mol (20.9 kJ/mol) and has the I3- ion oriented vertically (along the vertical axis) between two αCD molecules. The formation constant (Kf) of the complex is determined to be around 7.0 × 108 M-2 for both 15 and 25°C.
Mechanisms of oxidation reactions of iodide and hexacyanoferrate(II) ions, induced by the reaction between phosphinate ion and molecular oxygen in an aqueous solution
Kimura,Ieyama,Matsumoto,Shimada,Tsukahara
, p. 1871 - 1877 (2001)
When an I- solution was mixed with a PH2O2- solution which had been kept standing for given times of 5-40 min m the presence of molecular oxygen (O2), the I2 (or I3-)
snorkelling : Vs. diving in mixed micelles probed by means of a molecular bathymeter
Rodriguez-Mu?iz, Gemma M.,Gomez-Mendoza, Miguel,Nuin, Edurne,Andreu, Inmaculada,Marin, M. Luisa,Miranda, Miguel A.
, p. 10281 - 10288 (2017)
A photoactive bathymeter based on a carboxylic acid moiety covalently linked to a signalling methoxynaphthalene (MNP) fluorophore has been designed to prove the concept of snorkelling vs. diving in mixed micelles (MM). The carboxylic acid floats on the MM surface, while the MNP unit sinks deep in MM. The rate constants of MNP fluorescence quenching by iodide, which remains basically in water, consistently decrease with increasing spacer length, revealing different regions. This is associated with the distance MNP should dive in MM to achieve protection from aqueous reactants. Unequivocal proof of the exergonic photoinduced electron transfer was obtained from the UV-visible spectral signature of I3- upon steady-state photolysis. The applicability of the bathymeter was examined upon testing a family of MNP derivatives. The obtained results were validated by comparison with different lipophilicity tests: (i) a modified version of the Kow partition coefficient and (ii) the retention factor on thin layer chromatography. This concept could potentially be extended to test drugs or pharmacophores exhibiting any photoactive moiety.
Heterogeneous Catalysis in Solution. Part 18. The Catalysis by Carbons of Oxidation-Reduction Reactions
Austin, Jack M.,Groenewald, Theo,Spiro, Michael
, p. 854 - 859 (1980)
A mechanism of electron-transfer-through-the-solid is proposed to account for the widespread catalysis by carbons of redox reactions in solution.Charcoal catalysis of the aqueous reaction between Fe(3+) and I(-) ions was predicted, found, and studied kinetically.The activation energy of the heterogeneous process was only 24 kJ mol-1 compared with 100 kJ mol-1 for the homogeneous reaction.The (3-) + I(-) reaction in water was found to be catalysed by carbons as well as by several phthalocyanines.Neither reaction was catalysed by solids such as SiO2 or Ba which do not conduct electronically.
Microemulsion as a Medium in Chemical Kinetics: The Persulfate-Iodide Reaction
Moya, Maria Luisa,Izquierdo, Carmen,Casado, Julio
, p. 6001 - 6004 (1991)
Rate constants are reported for the oxidation of iodide ions by persulfate in sodium bis(2-ethylhexyl)sulfosuccinate (aerosol OT or AOT)/decane/water microemulsions.The rate law is in the form v = k2->2->, where both concentrations are referred to the aqueous phase.The reaction rate is higher in microemulsions than when it takes place in a conventional aqueous medium.Results show that when the AOT concentration remains constant, the reaction rate decreases when increasing the molar ratio w = /, appearing to asymptotically approach the rate in bulk water as the amount of water in the microemulsions increases.For a given w value, the reaction rate shows no dependence on the surfactant concentration.
