bluuebunny/crossref_metadata_2025_split huggingface dataset:
Permanganate oxidation of glycine: Influence of amino acid on colloidal manganese dioxide
Authors: Insausti M. J. , Mata‐perez F. , Alvarez‐Macho P. 
Published: January 2005

AbstractPermanganate ion oxidizes glycine in phosphate buffered solutions, and the product obtained was identified as a soluble form of colloidal manganese dioxide. The influence of glycine on the colloidal product shows glycine concentration changes extinction coefficients of the colloidal product, and only when the influence of glycine has been eliminated, the theoretical and experimental reaction rates coincide. The dependence of the rate of flocculation on several experimental variables was also considered.
Theoretical interpretation of the kinetics and mechanisms of the HNO + HNO and HNO + 2NO reactions with a unified model
Authors: Lin M. C. , He Yisheng , Melius C. F. 
Published: January 2005

AbstractPreviously measured decay rates of HNO in the presence of NO have been kinetically modeled on the basis of thermochemical data calculated with the BAC‐MP4 technique. The results of this modeling, aided by TST‐RRKM calculations for the association of HNO and the isomerization, decomposition, and stabilization of the many dimers of HNO, reveal that the decay of HNO under NO‐lean conditions occurs primarily by association forming cis‐ and trans‐(HNO)2 at temperatures below 420 K. N2O, which is a relatively minor product, is believed to be formed by H2O elimination from cis‐HON  NOH, a product of succesive isomerization reactions: trans‐(HNO)2† → HN(OH)NO† → HN(O)NOH† → cis‐HON NOH†. The calculated rate constants, which fit experimental data quantitatively, can be represented by k = 1016.2 × T−2.40e−590/T cm3/mol sec for the HNO recombination reaction and k = 10−2.44T3.98e−600/T cm3/mol sec for N2O formation in the temperature range 80–420 K, at a total pressure of 710 torr H2 or He.Under NO‐rich conditions, HNO reacts predominantly by the exothermic termolecular reaction, HNO + 2NO → HN(NO)ONO → HN NO + NO2, with a rate contant of (6 ± 1) × 109 cm6/mol2 sec at room temperature, based on both HNO decay and NO2 production. All existing thermal kinetic data on HNO + HNO and HNO + 2NO processes can be satisfactorily rationalized with a unified model based on the thermochemical data obtained by BAC‐MP4 calculations.
Hydrolysis of schiff bases 2: Intramolecular catalysis of an ortho‐hydroxy group in nonionic surfactant systems
Authors: Mishra Pramila , Mishra Bijay K. , Behera Gopa B. 
Published: January 2005

AbstractThe rates of hydrolysis of N‐(2&4‐hydroxybenzylidene)‐2‐aminobenzothiazoles has been studied in the pH range 4–13 in a 10% dioxane‐water system and in various nonionic surfactant systems. The reaction is found to be due to water mediated intramolecular general base catalysis within the pH range 4.0 to 12.0 and due to nucleophilic catalysis beyond pH 12.0. A ten membered intermediate facilitating transannular attack of a water molecule on the methine carbon forming a naphthalene type transition state has been proposed. The reactivity difference in water and nonionic surfactants has been explained by a suitable entrapment model.
Rate constants for the gas‐phase reactions of Cl atoms with a series of hydrofluorocarbons and hydrochlorofluorocarbons at 298 ± 2 K
Authors: Tuazon Ernesto C. , Atkinson Roger , Corchnoy Stephanie B. 
Published: January 2005

AbstractA relative rate method has been used to determine rate constants for the gas‐phase reactions of a series of hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) at 298 ± 2 K and atmospheric pressure of air. Based on a rate constant for the reaction of the Cl atom with CH4 of (1.0 ± 0.2) − 10−13 cm3 molecule−1 s−1 at 298 K, the following Cl atom reaction rate constants (in units of 10−15 cm3 molecule−1 s−1) were obtained: CH3F, 340 ± 70; CH3CHF2, 240 ± 50; CH2FCl, 110 ± 25; CHFCl2, 21 ± 4; CHCl2CF3, 14 ± 3; CHFClCF3, 2.7 ± 0.6; CH3CFCl2, 2.4 ± 0.5; CHF2Cl, 2.0 ± 0.4; CH2FCF3, 1.6 ± 0.3; CH3CF2Cl, 0.37 ± 0.08; and CHF2CF3, 0.24 ± 0.05. These Cl atom reaction rate constants are compared with literature data and with the corresponding OH radical reaction rate constants. © John Wiley & Sons, Inc.
Pyrolysis of CH2ClCH3: Considerations about its molecular nature
Authors: Huybrechts G. , Hubin Y. , Van Mele B. 
Published: January 2005

AbstractNumerical integrations of a hypothetical radical chain reaction model have been performed for the pyrolysis of CH2ClCH3 which is known to be molecular. Analyses of the modelling results have led to a better understanding of the participation (or nonparticipation) of “dead” radicals in the self‐inhibition of the radical chain reaction. Attention is focused on the fact that apparently slow elementary reactions still may have to be taken into account in a pyrolysis mechanism when they produce “dead” radicals which can accumulate. © John Wiley & Sons, Inc.
Substrate structural effects in micellar catalysis with perfluorooctanoic acid
Authors: Berndt D. C. , He Z. , Ayoub M. E. 
Published: January 2005

AbstractRates of hydrolysis of a series of hydroxamic acids in aqueous acetonitrile, with perfluorooctanoic acid serving as a reactive counterion surfactant, have been determined. The pseudophase ion exchange model satisfactorily explains the surfactant effects. Variation in the structure of the hydrophobic moiety of the hydroxamic acid substrates was obtained by the incorporation of different chain lengths and differently substituted aryl groups into the substrate. The major influence of the change in substrate structure is on the binding constant for binding of the substrate to the surfactant aggregate. The number of substitutions on the aryl ring appears to be more important than the total number of carbon atoms in the substrate. © John Wiley & Sons, Inc.
Relative rate constant measurements for the gas‐phase reactions of hydroxyl radicals with 4‐methyl‐2‐pentanone, trans‐4‐octene, and trans‐2‐heptene
Authors: O'rji Lawrence N. , Stone Daniel A. 
Published: January 2005

AbstractThe relative OH reaction rates from the simulated atmospheric oxidation of 4‐methyl‐2‐pentanone, trans‐4‐octene, and trans‐2‐heptene have been measured. Reactions were carried out at 297 ± 2 K in 100‐liter FEP Teflon®‐film bags. The OH radicals were produced from the photolysis of methyl nitrite. The measured rate constants (×1011 cm3 molecule−1 s−1) were as follows: 6.77 ± 0.50 for trans‐4‐octene, 1.40 ± 0.07 for 4‐methyl‐2‐pentanone, and 6.70 ± 0.23 for trans‐2‐heptene using an absolute rate constant of 2.63 × 1011 cm3 molecule−1 s−1 for the reaction of OH with propene; the principal reference organic. © John Wiley & Sons, Inc.
Effects of nitric oxide on the thermal decomposition of methyl nitrite: Overall kinetics and rate constants for the HNO + HNO and HNO + 2NO reactions
Authors: He Y. , Lin M. C. 
Published: January 2005

AbstractThe effects of NO on the decomposition of CH3ONO have been investigated in the temperature range 450–520 K at a constant pressure of 710 torr using He as buffer gas. The measured time‐dependent concentration profiles of CH3ONO, NO, N2O, and CH2O can be quantitatively accounted for with a general mechanism consisting of various reactions of CH3O, HNO, and (HNO)2. The results of kinetic modeling with sensitivity analyses indicate that the disappearance rate of CH3ONO is weakly affected by NO addition, whereas that of the HNO intermediate strongly altered by the added NO. In the presence of low NO concentrations, the modeling of N2O yields leads to the rate constant for the bimolecular reaction, HNO + HNO → N2O + H2O (25):

In the presence of high NO concentrations (PNO > 50 torr), the modeling of CH2O yields gives the rate constant for the termolecular radical formation channel, HNO + 2NO → HN2O + NO2 (35):

Discussion on the mechanisms for reactions (25) and (35), and the alkyl homolog of (35), RNO + 2NO, is presented herein. © John Wiley & Sons, Inc.
Rate constants for the elementary reactions between CN radicals and CH4, C2H6, C2H4, C3H6, and C2H2 in the range: 295 ⩽ T/K ⩽ 700
Authors: Herbert Lee , Smith Ian W. M. , Spencer‐smith Rowland D. 
Published: January 2005

AbstractPulsed laser photolysis, time‐resolved laser‐induced fluorescence experiments have been carried out on the reactions of CN radicals with CH4, C2H6, C2H4, C3H6, and C2H2. They have yielded rate constants for these five reactions at temperatures between 295 and 700 K. The data for the reactions with methane and ethane have been combined with other recent results and fitted to modified Arrhenius expressions, k(T) = A′(298) (T/298)n exp(−θ/T), yielding: for CH4, A′(298) = 7.0 × 10−13 cm3 molecule−1 s−1, n = 2.3, and θ = −16 K; and for C2H6, A′(298) = 5.6 × 10−12 cm3 molecule−1 s−1, n = 1.8, and θ = −500 K. The rate constants for the reactions with C2H4, C3H6, and C2H2 all decrease monotonically with temperature and have been fitted to expressions of the form, k(T) = k(298) (T/298)n with k(298) = 2.5 × 10−10 cm3 molecule−1 s−1, n = −0.24 for CN + C2H4; k(298) = 3.4 × 10−10 cm3 molecule−1 s−1, n = −0.19 for CN + C3H6; and k(298) = 2.9 × 10−10 cm3 molecule−1 s−1, n = −0.53 for CN + C2H2. These reactions almost certainly proceed via addition‐elimination yielding an unsaturated cyanide and an H‐atom. Our kinetic results for reactions of CN are compared with those for reactions of the same hydrocarbons with other simple free radical species. © John Wiley & Sons, Inc.
Kinetic modeling of propane oxidation and pyrolysis
Authors: Dagaut Philippe , Cathonnet Michel , Boettner Jean‐Claude 
Published: January 2005

AbstractPropane oxidation in jet‐stirred reactor was modeled using a comprehensive kinetic reaction mechanism including the most recent findings concerning the kinetics of the reactions involved in the oxidation of C1C4 hydrocarbons. The present detailed mechanism is able to reproduce experimental species concentration profiles obtained in our high‐pressure jet‐stirred reactor (900 ⩽ T/K ⩽ 1200; 1 ⩽ P/atm ⩽ 10; 0.15 ⩽ ϕ ⩽ 4) and in a turbulent flow reactor at 1 atm; ignition delay times measured in shock tube (1200 ⩽ T/K ⩽ 1700; 2 ⩽ P/atm ⩽ 15; 0.125 ⩽ ϕ ⩽ 2); H‐atoms concentrations measured in shock tube during the pyrolysis of propane and burning velocities of freely propagating premixed propane‐air laminar flames. The computed results are discussed in terms of pressure and equivalence ratio (ϕ) effects on propane oxidation. The same detailed kinetic reaction mechanism can also be used to model the oxidation of methane, ethylene, ethane, and propene in similar conditions. © John Wiley & Sons, Inc.
Approach to equilibrium after dilution of a monomer/dimer mixture. Measurement of the rate constant for dissociation of trityl dimer by stopped‐flow methods
Authors: Sóley kristjánsdóttir S. , Moody Anne E. , Norton Jack R. 
Published: January 2005

AbstractA general expression is derived for the approach to a new equilibrium when a monomer/dimer solution is diluted by a factor of n. The error introduced by a simple exponential treatment is analyzed. The response of a trityl monomer/dimer equilibrium to dilution by a factor of two in a stopped‐flow apparatus has been used to measure the rate constant k11. The results fall on the same Eyring plot with those obtained at lower temperatures, by another method, in the early 1930's by Ziegler and co‐workers. © John Wiley & Sons, Inc.
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Kinetics and mechanism of oxidation of tetrahydrofurfuryl alcohol by dihydroxydiperiodatonickelate (IV) complex in aqueous alkaline medium
Authors: Li Zhi‐Ting , Wang Feng‐Li , Wang An‐Zhou 
Published: January 2005

AbstractThe kinetics of oxidation of tetrahydrofurfuryl alcohol by dihydroxydiperiodatonickelate (IV) complex in the temperature range of 20–35°C has been studied by spectrophotometry in aqueous alkaline medium. The reaction order in [Ni(IV)] was found to be unity and that in [alcohol] to be 1.64–1.69. The rate of oxidation increases with increase in [OH−] and decreases with increase in [IO4−], indicating that dihydroxymonoperiodatonickelate (IV) complex is the reactive species of oxidant. Salt effect studies indicated that the reaction is of ion‐dipole type. Under the protection of nitrogen the reaction system does not induce polymerization of acrylonitrile or acrylamide, which indicates that a one‐step two‐electron transfer mechanism without free radical intermediate may be in operation. A mechanism involving a preequilibrium of an adduct formation between Ni(IV) and alcohol has been proposed. All the experimental phenomena can be explained by the equation derived from the mechanism. The activation parameters of the rate‐determining step have been calculated. © John Wiley & Sons, Inc.
The yield of CH3S from the reaction of OH with CH3SSCH3
Authors: Dominé Florent , Ravishankara A. R. 
Published: January 2005

AbstractThe products of the reaction of OH with CH3SSCH3 (DMDS) were investigated at 298 K using a flow tube reactor coupled to a photoionization mass spectrometer and a pulsed photolysis‐pulsed laser induced fluorescence apparatus. The results from the former apparatus were semi‐quantitative and showed that CH3S and CH3SOH are produced in the title reaction. The latter apparatus was used to quantify the yield of CH3S in the title reaction. The measured yield was 0.28 ± 0.20, independent of pressure and buffer gas, suggesting that products other than CH3S and CH3SOH are also important in this reaction. The quoted uncertainty is at the 95% confidence level and includes estimated systematic errors. © John Wiley & Sons, Inc.
A kinetic study of the reduction of toluidine blue with thiourea in acidic solution
Authors: Jonnalagadda S. B. , Tshabalala D. 
Published: January 2005

AbstractA detailed kinetic study of the reaction of toluidine blue (tolonium chloride) (TB+ Cl−) with thiourea (TU) in aqueous hydrochloric acid solution is reported. The reaction was first order with respect to toluidine blue and the reductant and second order with respect to [H+]. Thiourea had a 2:1 stoichiometric ratio with TB+. Toluidine blue was reduced to a colorless base in two one‐electron reduction steps and TU was oxidized to thioformamidinium ion, which dimerized rapidly to give stable dithioformamidinium ion. The energy parameters obtained for TB+‐TU reaction were mean energy of activation (Ea′) = 26.7 ± 2.4 kJ M−1; enthalpy of activation (ΔH#) = 24.2 kJ M−1; frequency factor (A) = 1.04 × 104 M−3 s−1; and entropy of activation (ΔS#) = −176.35 J M−1 s−1. © John Wiley & Sons, Inc.
Nitrenium ions in N‐chloro‐α‐amino acids decomposition?
Authors: Armesto X. L. , Canle L. M. , Losada M. , Santaballa J. A. 
Published: January 2005

AbstractThis article deals with the kinetics of decomposition of four isomers: NCl‐(L)‐2‐Aminohexanoic acid, NCl‐(L)‐Leucine, NCl‐(L)‐Isoleucine, and NCl‐(L)‐tert‐Leucine, in mild acid and basic aqueous solution. An alternative mechanism for this process which takes place through a nitrenium‐like ion transition state is proposed. This mechanism is in consonance with the experimental data and with those available from the literature. © 1993 John Wiley & Sons, Inc.
An operational approach to N‐Cl‐α‐amino acids decomposition
Authors: Armesto X. L. , Canle M. L. , Losada M. , Santaballa J. A. 
Published: January 2005

AbstractIt has been usually thought that the rate of N‐Cl‐α‐amino acids decomposition changes and that their coefficient of molar absorptivity falls when pH < 5, which has been explained on the basis of a hypothetical process of protonation at the N‐Cl‐amino group.We have proved: (i) the absence of protonation at the N‐Cl‐amino group, at least when pH > 2−; (ii) the effect of the method of mixing on the reaction rate; (iii) the absolute necessity of a very careful choice of buffers and solvents; and (iv) the need to check the accuracy of the mathematical model to describe the chemical processes. © 1993 John Wiley & Sons, Inc.
Kinetics and thermochemistry of the reaction of benzyl radical with O2: Investigations by discharge flow/laser induced fluorescence between 393 and 433 K
Authors: Elmaimouni L. , Minetti R. , Sawerysyn J. P. , Devolder P. 
Published: January 2005

AbstractThe kinetics of the reaction of the benzyl radical with molecular oxygen has been studied between 393 and 433 K. The Discharge Flow technique with detection of benzyl radicals by Laser Induced Fluorescence in their visible absorption band has been used. All experiments have been performed at ≈1 torr in helium as the buffer gas. The radical benzyl decay plots are characteristic of the approach to equilibrium between benzyl and benzylperoxy: benzyl + O2 \documentclass{article}\pagestyle{empty}\begin{document}$ \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\longrightarrow\over {\smash{\longleftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} $\end{document} benzylperoxy (k3, k−3). Thanks to a reasonable assumption concerning the standard entropy of the reaction (3) (ΔS298°=−29 cal mol−1 K−1), based on the additivity rules of Benson, the following reaction enthalpy is derived for reaction (3): ΔH298°=(−20 ± 1 kcal mol−1). This latter value is compared with a few enthalpies of other related reactions available in the literature. © 1993 John Wiley & Sons, Inc.
Rate constants for some reactions of inorganic radicals with inorganic ions. Temperature and solvent dependence
Authors: Padmaja S. , Neta P. , Huie R. E. 
Published: January 2005

AbstractRate constants for several reactions of inorganic radicals with inorganic anions in aqueous and aqueous/acetonitrile solutions have been measured as a function of temperature by laser flash photolysis. The reactions studied were (1) Cl2− + N3−, (2) Br2− + N3−, (3) Cl2− + SCN−, (4) Br2− + SCN−, (5) SO4− + Cl−, (6) SO4− + CO32−, and (7) N3− + I−. The rate constants were corrected for ionic strength and ranged from 106 to 109 L mol−1 s−1. The Arrhenius activation energies varied from 2 to 12 kJ mol−1 for the first 4 reactions, were higher for reaction 6, and negative for reaction 5. The pre‐exponential factors also varied considerably with log A ranging from 5 to 14. The values of k298 decreased in most cases by more than an order of magnitude upon increasing the acetonitrile (ACN) fraction from 0 to 70%. For most reactions, this decrease in k298 was due to changes in log A with little regularity in the small changes observed in Ea. For reaction 7, k298 was practically unchanged due to compensating effects of the changes in Ea and log A with ACN mol fraction, giving an isokinetic relationship. An isokinetic relationship was also observed in the case of reaction 6; Ea and log A change in parallel while changing ACN mol fraction. Reaction 3 (Cl2− + SCN−) was also studied in water/t‐butanol and water/acetic acid mixtures. Linear correlation was found between log k and the dielectric constant of the medium for water/ACN and water/t‐BuOH but the lines for the two solvent mixtures had different slopes, suggesting specific solvation effects in addition to the primary solvent polarity effects. With water/acetic acid, k decreased and then increased upon addition of acetic acid. © 1993 John Wiley & Sons, Inc.
Kinetics of O(1D) reactions with bromocarbons
Authors: Thompson John E. , Ravishankara A. R. 
Published: January 2005

AbstractThe rate coefficients for the removal of O(1D) by reaction with the following seven bromocarbons were measured using time‐resolved vacuum UV atomic resonance fluorescence detection of O(3P): CH3Br, CH2Br2, CHBr3, CF3Br (Halon‐1301), CF2Br2 (Halon‐1202), CF2ClBr (Halon‐1211), and CF2BrCF2Br (Halon‐2402). The branching ratios for the quenching of O(1D) to O(3P) by the above molecules were also determined. From these measurements, the rate coefficients for reactive and nonreactive loss of O(1D) were calculated. These results are discussed in terms of their atmospheric relevance and trends in reactivity of O(1D) with hydrocarbons upon halogen substitution. © 1993 John Wiley & Sons, Inc.
Kinetics of the reactions of OH radicals with selected acetates and other esters under simulated atmospheric conditions
Authors: Williams Dale C. , O'Rji Lawrence N. , Stone Daniel A. 
Published: January 2005

AbstractThe relative hydroxyl radical reaction rate constants from the simulated atmospheric oxidation of selected acetates and other esters have been measured. Reactions were carried out at 297 ± 2 K in 100‐liter FEP Teflon®‐film bags. The OH radicals were generated from the photolysis of methyl nitrite in pure air. Using a rate constant of 2.63 × 10−11 cm3 molecule−1 s−1 for the reaction of OH radicals with propene, the principal reference organic compound, the rate constants (×1012 cm3 molecule−1 s−1) obtained for the acetates and esters used in this study are:

n–propyl acetate
3.42 ± 0.87

n–butyl acetate
5.71 ± 0.94

n–pentyl acetate
7.53 ± 0.48

2–ethoxyethyl acetate
10.56 ± 1.31

2–ethoxyethyl isobutyrate
13.56 ± 2.32

2–ethoxyethyl methacrylate
27.22 ± 2.06

4–pentene‐1‐yl acetate
43.40 ± 3.85

3–Ethoxyacrylic acid ethyl ester
33.30 ± 1.22

Error limits represent 2σ from linear least‐squares analysis of data.A linear correlation was observed for a plot of the measured relative rate constants vs. the number of CH2 groups per molecule of the following acetates: methyl acetate, ethyl acetate, n‐propyl acetate, butyl acetate, and pentyl acetate. © 1993 John Wiley & Sons, Inc.
Effect of Cetylpyridinium chloride on the electron transfer reactions of acetophenones with Ce(IV)
Authors: Panigrahi Ganesh P. , Sahu Bimal P. 
Published: January 2005

AbstractThe kinetics of electron transfer reactions between acetophenones with Ce(IV) have been studied in aqueous acetic acid medium in the presence of cationic micelle Cetylpyridinium chloride (CPyCl) at different temperatures. Kinetic data reveal first‐order dependence with respect to each of Ce(IV) and acetophenones. The cationic micelle, Cetylpyridinium chloride enhances the oxidation reactions. The catalysis fits to a model developed by Menger and Portnoy as well as Berezin's phase separation model. The binding and partition constants and the transfer free energy from water to micelle have been estimated and discussed, suggesting that the solubilization of both the reactants in the micellar phase, facilitates the oxidation. © 1993 John Wiley & Sons, Inc.
Ruthenium(III) catalyzed kinetics of chloroacetic acids oxidation by sodium N‐bromobenzenesulfonamide in hydrochloric acid medium
Authors: Ananda S. , Venkatesha B. M. , Mahadevappa D. S. , Gowda N. M. Made 
Published: January 2005

AbstractKinetics of uncatalyzed and Ru(III)‐catalyzed oxidations of mono‐, di‐, and tri‐chloroacetic acids by the title compound (bromamine‐B or BAB) in HCl medium has been studied at 40°C. The uncatalyzed reaction shows a first‐order dependence of the rate on [BAB], and fractional and zero orders in [acid] at low and high [HCl] ranges, respectively. The Ru(III)‐catalyzed reaction, on the other hand, shows a first‐order behavior on each of [BAB] and [substrate], second‐order dependence on [Ru(III)], and inverse fractional and inverse first orders in [acid] at low and high [HCl] ranges. Addition of halide ions and the reduction product of BAB, benzenesulfonamide, has no effect on the reaction rate. Variation of ionic strength of the medium has no influence on the reaction. Solvent isotope effect was studied using D2O. Activation parameters have been evaluated from the Arrhenius plots. Mechanisms consistent with the above kinetic data have been proposed. The protonation constant of monobromamine‐B evaluated from the uncatalyzed reaction is 12.4 while that evaluated from Ru(III) catalyzed reaction is 12.7. A Taft linear free‐energy relationship is noted for the catalyzed reaction with ρ* = 1.2 and 0.07 indicating that electron withdrawing groups enhance the rate. An isokinetic relation is observed with β = 338 K indicating that enthalpy factors control the reaction rate. © 1993 John Wiley & Sons, Inc.