bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of resin‐manganese(II) complexes in hydrogen peroxide decomposition
Authors: Salem Ibrahim A. 
Published: January 2005

AbstractThe kinetics of hydrogen peroxide decomposition has been investigated in the presence of Wofatit KPS (4% DVB, 40–80 μm) resin in the form of mono (mea), di (dea), triethanolamine (tea), ethylenediamine (eda), and N,N′‐diethylethylenediamine (deeda)‐ Mn(II) complexes. The rate constant k (per g dry resin) was evaluated over the temperature range 25–40°C. The reaction was first‐order with respect to [H2O2]. The rate constant, k, with the three ethanolamines decreased in the following order mea > dea > tea which is the same order of basicity. Also, k value with deeda is lower than eda as a result of steric hindrance. The peroxo metal complex which formed at the beginning of the reaction, was found to contain the catalytic active species. The rate of reaction was proportional to [Mn‐complex], [H2O2] and [H+]−1. The activation parameters were calculated and a probable reaction mechanism is proposed. © 1994 John Wiley & Sons, Inc.
Gas‐phase thermal decomposition of peroxy‐N‐butyryl nitrate
Authors: Grosjean Daniel , Williams Edwin L. , Grosjean Eric 
Published: January 2005

AbstractThe gas‐phase thermal decomposition rate of peroxy‐n‐butyryl nitrate (n‐C3H7C(O)OONO2, PnBN) has been measured at ambient temperature (296 K) and 1 atm of air relative to that of peroxyacetyl nitrate (CH3C(O)OONO2, PAN) using mixtures of PAN (14–19 ppb), PnBN (22–46 ppb), and nitric oxide (1.35–1.90 ppm). The PnBN/PAN decomposition rate ratio was 0.773 ± 0.030. This ratio, together with a literature value of 3.0 × 10−4 s−1 for the thermal decomposition rate of PAN at 296 K, yields a PnBN thermal decomposition rate of (2.32 ± 0.09) × 10−4 s−1. The results are briefly discussed by comparison with data for other peroxyacyl nitrates and with respect to the atmospheric persistence of PnBN. © 1994 John Wiley & Sons, Inc.
A shock tube study of the OH + OH → H2O + O reaction
Authors: Wooldridge Margaret S. , Hanson Ronald K. , Bowman Craig T. 
Published: January 2005

AbstractThe rate coefficient for the reaction
equation image
has been determined in mixtures of nitric acid (HNO3) and argon in incident shock wave experiments. Quantitative OH time‐histories were obtained by cw narrow‐linewidth uv laser absorption of the R1(5) line of the A2 σ+ ← X2 Πi (0,0) transition at 32606.56 cm−1 (vacuum). The experiments were conducted over the temperature range 1050–2380 K and the pressure range 0.18–0.60 atm. The second‐order rate coefficient was determined to be

with overall uncertainties of +11%, −16% at high temperatures and +25%, −22% at low temperatures. By incorporating data from previous investigations in the temperature range 298–578 K, the following expression is determined for the temperature range 298–2380 K

© 1994 John Wiley & Sons, Inc.
Kinetics and mechanisms of the gas‐phase reactions of the NO3 radical with aromatic compounds
Authors: Kwok Eric S. C. , Atkinson Roger , Arey Janet 
Published: January 2005

AbstractThe kinetics and nitrated products of the gas‐phase reactions of the NO3 radical with methoxybenzene, 1,2‐, 1,3‐, and 1,4‐dimethoxybenzene, dibenzofuran and dibenzo‐p‐dioxin have been investigated at 297 ± 2 K and in the presence of one atmosphere of air. A relative rate method was used for the kinetic measurements. No reactions of methoxybenzene or dibenzofuran with the NO3 radical were observed. The dimethoxybenzenes were observed to react by H‐atom abstraction and NO3 radical addition to the aromatic ring, while dibenzo‐p‐dioxin reacted by NO3 radical addition to the aromatic rings. For these compounds, the NO3 radical addition pathways were observed to be reversible. At the NO2 concentrations employed, the NO3‐aromatic adducts reacted with NO2 and the observed rate constants increased with increasing NO2 concentration. However, for dibenzo‐p‐dioxin the observed rate constant became independent of the NO2 concentration for concentrations ≥ 4.8 × 1013 molecule cm−3, and under these conditions the rate constant of 6.8 × 10−14 cm3 molecule−1 s−1 was taken to be that for addition of the NO3 radical to the aromatic rings. The proposed NO3 radical reaction mechanisms are discussed. © 1994 John Wiley & Sons, Inc.
Base hydrolysis of (αβ S)‐(o‐methoxy benzoato) (tetraethylenepentamine) cobalt(III) ion: A comparative study of the role of ion pairs and micelles
Authors: Acharya Achyuta N. , Dash Anadi C. 
Published: January 2005

AbstractThe kinetics of base hydrolysis of (αβ S)‐(o‐methoxy benzoato) (tetraethylenepentamine)cobalt(III) obeyed the rate law: kobs = kOH[OH−], in the range 0.05 ⩽ [OH−]T, mol dm−3 ⩽ 1.0, I = 1.0 mol dm−3, and 20.0–40.0°C. At 25°C, kOH = 13.4 ± 0.4 dm3 mol−1 s−1, ΔH≠ = 93 ± 2 kJ mol−1 and ΔS≠ = 90 ± 5 JK−1 mol−1. Several anions of varying charge and basicity, CH3CO2−, SO32−, SO42−, CO32−, C2O42−, CH2(CO2)22−, PO43−, and citrate3− had no effect on the rate while phthalate2−, NTA3−, EDTA4−, and DTPA5− accelerated the process via formation of the reactive ion pairs. The anionic (SDS), cationic (CTAB), and neutral (Triton X‐100) micelles, however, retarded the reaction, the effect being in the order SDS> CTAB > Triton X‐100. The importance of electrostatic and hydrophobic effects of the micelles on the selective partitioning of the reactants between the micellar and bulk aqueous pseudo‐phases which control the rate are discussed. © 1994 John Wiley & Sons, Inc.
Reactions of cobalt(III) complexes with free radicals derived from thymine
Authors: Chakrabarti S. , Mandal P. C. , Bhattacharyya S. N. 
Published: January 2005

AbstractThe nature of interaction of Co(III) complexes such as Co(III)EDTA and Co(III)NTA with transient adducts of thymine such as TOH˙, T˙−, and TH˙ formed in the gamma radiolysis of thymine were studied. The study shows that TOH radicals do not undergo electron transfer reaction with Co(III) complexes whence no radiosensitization of thymine by Co(III) complexes was observed. Electron transfer however, takes place from T˙− and TH˙ to Co(III) complexes. A plausible mechanism of radiolysis of thymine in presence of Co(III) complexes is discussed. © 1994 John Wiley & Sons, Inc.
Methyl isocyanide is an RRKM molecule after all
Authors: Shen Delin , Pritchard Huw O. 
Published: January 2005

AbstractClassical trajectory calculations on the methyl isocyanide molecule at energies above 25,000 cm−1 confirm that the rate of reaction to methyl cyanide is bimodal, with a very fast rate before 0.1 ps, and a slower rate from then on. We conclude that before 0.1 ps, the reacting molecules are unrandomized, but thereafter, they are essentially randomized, with decay to products being, to a good approximation, pure exponential. We estimate that the time for randomization is roughly 0.3 ps at energies near the reaction threshold of 13,500 cm−1. © 1994 John Wiley & Sons, Inc.
Kinetics of the reaction of C6H5 with HBr and DBr
Authors: Yu T. , Lin M. C. 
Published: January 2005

AbstractThe rate constants for the reaction of C6H5 with HBr and DBr have been measured with the cavity–ring–down method in the temperature range of 297 to 523 K and 297 to 500 K, respectively. These rate constants can be effectively represented, in units of cm3/s, by

Both activation energies are similar and positive, contrary to those of alkyl radical reactions, all of which exhibit negative temperature dependencies. The difference, as pointed out before [1], could be accounted for by the electron‐withdrawing effect of the phenyl vis‐à‐vis the electron‐donating ability of the alkyls. © 1994 John Wiley & Sons, Inc.
CO2 laser excitation of triethylsilane: Time resolved luminescence of diethylsilyl radical
Authors: Papagiannakopoulos Panos , Lazarou Yannis G. 
Published: January 2005

AbstractThe infrared multiphoton excitation of triethylsilane in the gas phase, with a pulsed CO2 laser at high intensities (I > 700 MW/cm2), produced an intense luminescence. The spectrum and time profile of this luminescence was studied as a function of pressure, and laser frequency. The radiative lifetime of this emission was 357 ± 10 ns, and the quenching rates by Cl2 and NO were determined from lifetime measurements. A reasonable mechanism for the interpretation of this luminescence involves the initial infrared multiphoton decomposition of triethylsilane, followed by the secondary infrared multiphoton excitation of the primary photofragment diethylsilyl radical, which subsequently undergoes relaxation to an excited electronic state. The addition of O2 resulted in a new chemiluminescence at shorter wavelengths, which corresponds to the SiO* chromophore group. © 1994 John Wiley & Sons, Inc.
General base catalysis in the decomposition of N‐Cl‐Valine in aqueous solution
Authors: Abia Ll , Armesto X. L. , Canle L. M. , García M. V. , Losada M. , Santaballa J. A. 
Published: January 2005

AbstractThis article analyzes the kinetics of the decomposition of N‐Cl‐Valine in aqueous solution, which is formed rapidly by chlorination of Valine with sodium hypochlorite. A general‐base catalyzed process not yet described is reported. The experimental evidence shows two competitive decomposition paths: an unimolecular concerted fragmentation process (k = (1.8 ± 0.1) · 10−4 s−1 at 298 K) and the other one is an E2 elimination process whose importance increases with pH and depends on the nature and the concentration of the bases present in the medium. © 1994 John Wiley & Sons, Inc.
Rate constants for the gas‐phase reactions of Ozone with unsaturated Aliphatic Alcohols
Authors: Grosjean Eric , Grosjean Daniel 
Published: January 2005

AbstractThe gas‐phase reaction of ozone with unsaturated alcohols in air has been investigated at atmospheric pressure and ambient temperature (288–291 K). Cyclohexane was added to scavenge the hydroxyl radical which forms as a product of the ozone–unsaturated alcohol reaction. The reaction rate constants, in units of 10−18 cm3 molecule−1 s−1, are 16.2 ± 0.7 for (±) 3‐buten‐2‐ol, 17.9 ± 1.8 for 1‐penten‐3‐ol, 10.0 ± 0.3 for 2‐methyl‐3‐buten‐2‐ol, 169 ± 25 for cis‐2 penten‐1‐ol, and 251 ± 41 for 2‐buten‐1‐ol (mixture of isomers). Substituent effects on reactivity are discussed. The reactivity of unsaturated alcohols towards ozone is similar to that of their alkene structural homologues. Implications of these results with respect to the atmospheric persistence of unsaturated alcohols are briefly discussed. © 1994 John Wiley & Sons, Inc.
Rate constants for the gas‐phase reactions of O3 with a series of Terpenes and OH radical formation from the O3 reactions with Sesquiterpenes at 296 ± 2 K
Authors: Shu Yonghui , Atkinson Roger 
Published: January 2005

AbstractRate constants for the gas‐phase reactions of O3 with the sesquiterpenes α‐cedrene, α‐copaene, β‐caryophyllene, α‐humulene, and longifolene, and with the monoterpenes limonene, terpinolene, α‐phellandrene, and α‐terpinene, have been measured using a relative rate technique at 296 ± 2 K and atmospheric pressure of air. The rate constants obtained (in units of 10−17 cm3 molecule−1 s−1) are: limonene, 20.1 ± 5.1; terpinolene, 188 ± 67; α‐phellandrene, 298 ± 105; α‐terpinene, 2110 ± 770; α‐cedrene, 2.78 ± 0.71; α‐copaene, 15.8 ± 5.6; β‐caryophyllene, 1160 ± 430; α‐humulene, 1170 ± 450; and longifolene, <0.07, where the indicated errors include the estimated overall uncertainties in the rate constants for the reference organics. Hydroxyl radical formation yields were also determined for the O3 reactions with the sesquiterpenes, of 0.67 for α‐cedrene, 0.35 for α‐copaene, 0.06 for β‐caryophyllene, and 0.22 for α‐humulene, all with estimated overall uncertainties of a factor of ca. 1.5. The tropospheric lifetimes of the sesquiterpenes due to reaction with O3 are calculated. © 1994 John Wiley & Sons, Inc.
Kinetic analysis of reversible thermal decomposition of solids
Authors: Vyazovkin Sergey , Linert Wolfgang 
Published: January 2005

AbstractThe isoconversional method was used to elucidate the kinetics of reversible solid‐state reactions occurring under nonisothermal linear heating. The characteristic dependencies of the effective activation energy (E) on the extent of conversion (W) were established for two model processes: a reversible first‐order reaction and a reversible reaction followed by an irreversible one. For the first process, E is almost independent of W and varies between the activation energy of the direct and inverse reaction. For the second, process with an endothermic reversible step, the dependence of E on W is of decreasing shape. The effective activation energy is limited by the sum of the activation energy of the irreversible reaction and the enthalpy of the reversible reaction, at low conversions, and by the activation energy of the irreversible reaction at high conversions. Analyses of the kinetic data for the dehydration of crystalhydrates, as well as other processes proceeding through a reversible step, show the dependencies of E on W characteristic of a reversible reaction followed by an irreversible one. © 1995 John Wiley & Sons, Inc.
Kinetic study of the reaction of chlorine atoms with CF3I and the reactions of CF3 radicals with O2, Cl2 and NO at 296 K
Authors: Kaiser E. W. , Wallington T. J. , Hurley M. D. 
Published: January 2005

AbstractThe kinetics of the gas‐phase reaction of Cl atoms with CF3I have been studied relative to the reaction of Cl atoms with CH4 over the temperature range 271–363 K. Using k(Cl + CH4) = 9.6 × 10−12 exp(−2680/RT) cm3 molecule−1 s−1, we derive k(Cl + CF3I) = 6.25 × 10−11 exp(−2970/RT) in which Ea has units of cal mol−1. CF3 radicals are produced from the reaction of Cl with CF3I in a yield which was indistinguishable from 100%. Other relative rate constant ratios measured at 296 K during these experiments were k(Cl + C2F5I)/k(Cl + CF3I) = 11.0 ± 0.6 and k(Cl + C2F5I)/k(Cl + C2H5Cl) = 0.49 ± 0.02. The reaction of CF3 radicals with Cl2 was studied relative to that with O2 at pressures from 4 to 700 torr of N2 diluent. By using the published absolute rate constants for k(CF3 + O2) at 1–10 torr to calibrate the pressure dependence of these relative rate constants, values of the low‐ and high‐pressure limiting rate constants have been determined at 296 K using a Troe expression: k0(CF3 + O2) = (4.8 ± 1.2) × 10−29 cm6 molecule−2 s−1; k∞(CF3 + O2) = (3.95 ± 0.25) × 10−12 cm3 molecule−1 s−1; Fc = 0.46. The value of the rate constant k(CF3 + Cl2) was determined to be (3.5 ± 0.4) × 10−14 cm3 molecule−1 s−1 at 296 K. The reaction of Cl atoms with CF3I is a convenient way to prepare CF3 radicals for laboratory study. © 1995 John Wiley & Sons, Inc.
Theoretical analysis of the rate constants for the interstellar reaction N+OH→NO+H
Authors: Cobos C. J. 
Published: January 2005

AbstractThe title reaction, a key elementary process involved in the chemistry of molecular clouds, has been theoretically studied over the 5–600 K temperature range. Rate constants calculations have been carried out using the full version of the statistical adiabatic channel model in conjunction with a potential energy surface that has been derived from recent ab initio quantum chemical data. By using various switching functions, the influence of the attenuation of the bound‐complex bending frequency upon NOH bond elongation on the temperature dependence of the reaction was investigated. The rate constants exhibit a slightly positive temperature dependence with a calculated rate constant value at 300 K in very good agreement with the measured value. A comparison with the available experimental data between 250 and 515 K suggests that recrossing trajectories might occur with increasing importance as the temperature increases. However, the nonstatistical recrossing effects are expected to be of minor importance at interstellar temperatures such that the rate constants over the 5–200 K temperature range are given by k = 8.41 × 10−12 T+0.30 cm3 molecule−1 s−1. The rate constant calculated at 10 K is consistent with that derived in the astrochemical modeling of the L134N dark cloud. Rate constants for individual quantum states are also presented. © 1995 John Wiley & Sons, Inc.
The kinetics of the B2H6/O (3P) system at room temperature
Authors: Gal Gyora , Bar‐Ziv Ezra 
Published: January 2005

AbstractAn experimental study of the kinetics of the B2H6/O (3P) system at room temperature, is presented. Modeling was based on a multiple‐parameter fitting process to a complex kinetic mechanism. The aim of the study was to propose and evaluate a preferred set of elementary reactions which might be important for the oxidation of boron‐hydrides. In this study, relative concentration‐vs.‐time profiles of the radicals OH and BO2 were measured in a low pressure flow reactor, by the technique of laser‐induced‐fluorescence. A range of almost two orders of magnitude in the initial fuel to oxygen ratio was covered, while the residence times of the gases in the reactor were up to 1 s. A comprehensive kinetic mechanism was constructed from the available measured and estimated data in literature. After the fitting process and dropping all of the reactions with negligible contribution, a 46 elementary reactions mechanism was obtained. In this mechanism, 27 reactions are not measured and their rate coefficients were used as the adjustable (within reasonable limits deduced from kinetic and thermodynamic considerations) parameters of the fitting process. Good agreement was obtained between all of the measured and calculated profiles. From sensitivity analysis it was found that only a limited group of these reactions highly contributes to the calculated concentrations of OH and BO2. With only the highly contributing reactions and all the oxygenhydrogen reactions which are measured and relatively well known, a 30 elementary reactions mechanism was obtained. In this mechanism only 13 reactions are not measured and the agreement between the measured and the calculated profiles is still reasonable. To demonstrate the possible usefulness of the proposed mechanism, the rate coefficient of the reaction B2H6 + OH → B2H5 + H2O which was not measured before, was directly measured in our experimental set‐up. The rate coefficient that was obtained in the direct measurement is (3.3 ± 1.1) × 1011 cm3mol−1s−1, in excellent agreement with the predicted one by the multiple‐parameter‐fitting process, which was 2 × 1011 cm3mol−1s−1. © 1995 John Wiley & Sons, Inc.
Thermal decomposition of 1‐butyne in shock waves
Authors: Hidaka Yoshiaki , Higashihara Tetsuo , Oki Takashi , Kawano Hiroyuki 
Published: January 2005

Abstract1‐Butyne diluted with Ar was heated behind reflected shock waves over the temperature range of 1100–1600 K and the total density range of 1.36 × 10−5−1.75 × 10−5 mol/cm3. Reaction products were analyzed by gas‐chromatography. The progress of the reaction was followed by IR laser kinetic absorption spectroscopy. The products were CH4, C2H2, C2H4, C2H6, allene, propyne, C4H2, vinylacetyiene, 1,2‐ butadiene, 1,3‐butadiene, and benzene. The present data were successfully modeled with a 80 reaction mechanism. 1‐Butyne was found to isomerize to 1,2‐butadiene. The initial decomposition was dominated by 1‐butyne → C3H3 + CH3 under these conditions. Rate constant expressions were derived for the decomposition to be k7 = 3.0 × 1015 exp(−75800 cal/RT) s−1 and for the isomerization to be k4 = 2.5 × 1013 exp(−65000 cal/RT) s−1. The activation energy 75.8 kcal/mol was cited from literature value and the activation energy 65 kcal/mol was assumed. These rate constant expressions are applicable under the present experimental conditions, 1100–1600 K and 1.23–2.30 atm. © 1995 John Wiley & Sons, Inc.
Evidence of protonation during the oxidation of some aryl alcohols by permanganate in perchloric acid medium and mechanism of the oxidation processes
Authors: Sen Pratik K. , Sanyal Ankan , Sen Gupta Kalyan K. 
Published: January 2005

AbstractThe oxidation of benzyl alcohol and methoxy‐, chloro‐, and nitro‐ substituted benzyl alcohols by permanganate has been studied in aqueous and acetic acid medium in presence of perchloric acid. The reaction is first‐order in [MnO4−] and [XC6H4CH2OH], but the order is complex with respect to [H+]. Different thermodynamic parameters have been evaluated. The reaction occurs through the protonation of alcohol in a fast preequilibrium followed by a slow rate‐determining oxidation step. A two‐electron transfer oxidation step has been suggested for benzyl alcohol and chloro‐ and nitro‐ substituted alcohols, while the oxidation of methoxy compounds involves a one‐electron transfer via a free‐radical mechanism. © 1995 John Wiley & Sons, Inc.
Atmospheric chemistry of FCOx radicals: Kinetic and mechanistic study of the FC(O)O2 + NO2 reaction
Authors: Wallington Timothy J. , Schneider William F. , Møgelberg Trine E. , Nielsen Ole J. , Sehested Jens 
Published: January 2005

AbstractA pulse radiolysis system was used to study the kinetics of the reaction of FC(O)O2 radicals with NO2. By monitoring the rate of the decay of NO2 using its absorption at 400 nm the reaction rate constant was determined to be (5.5 ± 0.6) × 10−12 cm3 molecule−1 s−1 at 296 K and 500–1000 mbar pressure of SF6 diluent. A long path length Fourier transform infrared spectrometer was used to investigate the thermal stability of the product FC(O)O2NO2. The rate of thermal decomposition of FC(O)O2NO2 was independent of the total pressure of N2 diluent over the range 100–700 torr and was fit by the expression k−3 = 6.0 × 1016 exp(−14150/T) s−1. The results are discussed in the context of the atmospheric chemistry of FCOx radicals. © 1995 John Wiley & Sons, Inc.
Kinetic study of the oxidation of L‐phenylalanine by potassium permanganate in acid medium
Authors: Insausti M. J. , Mata‐PÉRez F. , Alvarez‐Macho M. P. 
Published: January 2005

AbstractThe kinetics of permanganate oxidation of L‐phenylalanine in acid medium at a constant ionic strength has been investigated spectrophotometrically. An autocatalytic reaction was observed being autocatalyzed by a soluble form of Mn(IV).The reaction appears to involve a parallel consecutive reaction process in which Mn(IV) is formed as an intermediate and Mn(II) as a reaction product. A tentative mechanism consistent with the kinetics is discussed. © 1995 John Wiley & Sons, Inc.
Ionic strength effects in binary aqueous mixtures: Study of the reaction between Co(en)2(2‐pzCO2)2+ and Fe(CN)5H2O3−
Authors: Rodríguez Amalia , Pérez‐tejeda Pilar , Jiménez Rafael , Sánchez Francisco , López Pilar , Calvente Juan José , Moyá Marí Luisa 
Published: January 2005

AbstractThe reaction between Co(en)2(2−pzCO2)2+ (bis‐ethylenediamine (2‐pyrazinecarboxylato)cobalt(III)) and Fe(CN)5H2O3− (aquopentacyanoferrate(II)) to form the binuclear complex [(en)2Co( μ‐pzCO2)Fe(CN)5]− has been studied in several isodielectric binary mixtures at 298.2 K (cosolvents: methanol, ethanol, tertbutyl alcohol, ethyleneglycol, and glycerol). Results were rationalized by using a free energy relationship. The importance of correcting the rate constants obtained in the different mixtures from the ionic strength influence has been shown. © 1995 John Wiley & Sons, Inc.
Approximate analytic solution for the dissociation of molecular iodine in the presence of singlet oxygen
Authors: Perram Glen P. 
Published: January 2005

AbstractA computational study including sensitivity, nondimensional, and stedy‐state analyses of the gas‐phase kinetics associated with Chemical Oxygen‐Iodine Lasers (COIL) was performed to develop a simplified kinetic model and assess kinetic limitations to laser performance. A minimal set of 13 reactions is developed that adequately describes the time evolution of the major chemical constituents of a COIL device. A characteristic time for the dissociation of molecular iodine by singlet oxygen is established in terms of iodine fraction, water content, yield of singlet oxygen, and rate parameters. Finally, an approximate analytic solution to the iodine dissociation problem is established for a broad range of reagent concentrations. The current study is limited in applicability due to the exclusion of chemical heat release and reactive mixing phenomenon. © 1995 John Wiley & Sons, Inc.