bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical detection of NO3 and NO2 in “pure” HNO3 vapor, the liquid‐phase decomposition of HNO3
Authors: Crowley J. N. , Burrows J. P. , Moortgat G. K. , Poulet G. , Le Bras G. 
Published: January 2005

AbstractFlowing and static gas‐phase samples of HNO3 in O2 and N2 were analyzed by long‐path ultraviolet/visible (UV/VIS) spectroscopy to reveal the presence of both NO2 and NO3, the concentrations of which were calculated using differential absorption cross sections. NO2 is produced predominantly by the heterogeneous decomposition of HNO3, whereas NO3 is generated in the gas phase by the thermal decomposition of N2O5, a product of the self‐disproportionation of liquid HNO3. © 1993 John Wiley & Sons, Inc.
Reactions of azolium cations. I. Kinetics and mechanism of alkylation of 5‐phenyltetrazole with isopropyl alcohol in aqueous sulfuric acid media
Authors: Koren A. O. , Gaponik P. N. , Ostrovskii V. A. 
Published: January 2005

AbstractAlkylation of 5‐phenyltetrazole with isopropyl alcohol in 84–99% sulfuric acid medium occurs regioselectively at N2 position of the heterocycle to produce 2‐isopropyl‐5‐phenyltetrazole. The regioselectivity is conditioned by 1H, 4H‐5‐phenyltetrazolium cation being the alkylation substratum. The reaction mechanism is proved to be two‐stage one. Its first and rate‐limiting stage is an interaction between the azolium cation and isopropyl cation generated from protonated isopropyl alcohol. The reaction rate constant was estimated as 0.47 L mol−1s−1at 25°C. Water activity scale was used for quantitative description of equilibrium of isopropyl cation formation from the protonated alcohol, and the equilibrium constant pKR+= −5.3 was evaluated from the data of the alkylation kinetics. © 1993 John Wiley & Sons, Inc.
Isotope effect in Ni + C2H4 (C2D4) association reaction
Authors: Mitchell S. A. 
Published: January 2005

AbstractThe association reactions of atomic nickel with ethene and fully deuterated ethene in carbon dioxide buffer gas at 295 K have been investigated in the pressure range 5–100 torr, using a laser photolysis‐laser fluorescence technique. By comparison with results of ab initio quantum chemistry calculations for the complex Ni[C2H4], the data are shown to be consistent with reaction on both ground and excited state potential energy surfaces. A simple rate equations treatment is described which shows the form of the pressure dependence of the second‐order recombination rate coefficient in this case. Under conditions which are expected to hold for the Ni + C2H4 (C2D4) reaction, the pressure dependence has the standard Lindemann‐Hinshelwood form, with the limiting high pressure rate constant given by an apparent value which reflects the degree to which the participating electronic states are coupled by nonadiabatic transitions. The limiting high pressure behavior of the recombination rate coefficient for Ni + C2H4 is not strongly affected by deuterium isotope substitution. However, the effect on the low pressure rate constant is large and consistent with RRKM unimolecular reaction theory. This validates the use of RRKM calculations for estimating the binding energy of the complex from kinetic data. The binding energy of Ni[C2H4] is estimated to be 35.2 ± 4.2 kcal mol−1. © 1994 John Wiley & Sons, Inc.
Hetero‐homogeneous pyrolysis of isobutane and platinum wall‐effects in conditioned or unconditioned reactors
Authors: Zils R. , Perrin D. , Martin R. 
Published: January 2005

AbstractThe pyrolysis of isobutane has been studied at 500°C in a “Pyrex” static reactor packed with platinum. It is shown that both dehydrogenation and demethanat on rates are strongly depressed by the metal packing. The reaction rates are very sensitive to the amount of cabonaceous coating which is deposited on the walls. As this amount increases, both rates first increase, go through a maximum and decrease. These observations are compared with those previously made on propane pyrolysis in a “Pyrex” reactor packed with stainless steel. The present results are interpreted on the basis of a hetero‐homogeneous chain mechanism in which the selectivity of the free‐radical reaction is not altered referring to the unpacked reactor. © 1994 John Wiley & Sons, Inc.
Study of the kinetics and equilibrium of the benzyl‐radical association reaction with molecular oxygen
Authors: Fenter Frederick F. , Nozière Barbara , Caralp Francoise , Lesclaux Robert 
Published: January 2005

AbstractThe forward rate constant, k1, and the equilibrium constant, Kp, for the association reaction of the benzyl radical with oxygen have been determined. The rate constant k1 was measured as a function of temperature (between 298 and 398 K) and pressure (at 20 and 760 torr of N2) by two different techniques, argon‐lamp flash photolysis and excimer‐laser flash photolysis, both of which employed UV absorption spectroscopy (at 253 nm and 305 nm, respectively) to monitor the benzyl radical concentration. Over the range of conditions studied, we find that the reaction is independent of pressure and is almost independent of temperature, which is in accord with two early studies of the reaction but in apparent disagreement with more recent work. For our results in 760 torr of N2 and for 298 < T/K < 398, a linear least‐squares fitting of the data yield the expression: k1 = (7.6 ± 2.4) × 10−13 exp[(190 ± 160)K/T] cm3 molecule−1 s−1. With the flash‐photolysis technique, we determined Kp over the temperature range 398–525 K. Experimental values were analyzed alone and combined with theoretically determined entropy values of the benzyl and benzylperoxy radicals to determine the enthalpy of reaction: ΔH = (−91.4 ± 4) kJ mol−1. Previous work on the benzyl radical enthalpy of formation allows us to calculate ΔH°f 298 (Benzylperoxy) = (117 ± 6) kJ mol−1. In addition, we carried out an RRKM calculation of k1 using as constraints the thermodynamic information gained by the study of Kp. We find that all the studies of the association reaction are in good agreement once a fall‐off effect is taken into account for the most recent work conducted at pressures near 1 torr of helium. © 1994 John Wiley & Sons, Inc.
Relationship between bond dissociation energies and activation energies for bond scission reactions
Authors: Smith G. P. , Manion J. A. , Rossi M. J. , Rodgers A. S. , Golden D. M. 
Published: January 2005

AbstractBond dissociation energies are frequently derived from values of the high pressure activation energy for bond scission reactions. The value derived depends on the transition state structure chosen for the reaction. We consider several models of the transition state and show that the variation in derived BDE values can be quite substantial, 3 to 6 kcal/mol at the high temperatures of pyrolysis kinetics. Application of the restricted Gorin model of the transition state results in BDE values in good agreement with current thermochemistry, while the other models tested result in lower to much lower values. © 1994 John Wiley & Sons, Inc.
Improved method for fitting falloff data
Authors: Poole James S. , Gilbert Robert G. 
Published: January 2005

AbstractAn extension of the dimensionless treatment of Troe is developed for fitting falloff data from unimolecular and recombination reactions. This method using dimensionless parametrizations derived from accurate numerical solutions of the master equation for system with any type of activated complex and energy transfer probability distribution, is as easily implemented as Troe's method, and allows global fitting of an entire set of pressure‐ and temperature‐dependent rate coefficients. © 1994 John Wiley & Sons, Inc.
0(3P) attack on Boranes. III. B10H14
Authors: Cheng H‐Z. , Bauer S. H. 
Published: January 2005

AbstractAs in our previous studies, 0(3P), generated by titration with NO of microwave discharged N2 (He carrier), was mixed with B10H14 vapor (Ar carrier) in a flow‐tube reactor. Levels of product OH were determined via LIF on an absolute basis, for dwell times 4 to 18 ms. The system was calibrated with C2H6, run under identical conditions. The reactants comprised approximately 1% of the flowing mixture. OH production is ≈62 greater from B10H14 than from B5H9 (under similar conditions but at somewhat lower temperature). FTIR analyses of a solid product that condensed downstream on cold surfaces showed the presence of BOH ⃜OB hydrogen bonds and matched (but not perfectly) the calculated frequencies of HB(OH)2. © 1994 John Wiley & Sons, Inc.
Study of the pseudo‐steady‐state kinetics of CO2 hydrate formation and stability
Authors: Lund P. C. , Shindo Y. , Fujioka Y. , Komiyama H. 
Published: January 2005

AbstractThis article describes a dynamic model for formation and stability of CO2‐hydrate on the interface of liquid CO2(LCO2) and ocean water at large depths. Experimental results indicate that a thin film of hydrate naturally forms on the interfaces between LCO2 and water, and inhibits diffusion between the two phases. Experiments further shows that the flux of CO2 through the hydrate film is dependent of the CO2‐concentration in the ambient sea water. The model proposed here explains these phenomena by introducing four major mechanisms; diffusion of water to the LCO2‐phase, formation of hydrate in the LCO2‐hydrate interface, decay of hydrate in the water‐hydrate interface, and diffusion of CO2 through the water phase. The model explains the CO2 flux not by diffusion through the hydrate film, but suggest a mechanism of continuous hydrate formation and decay. The overall effect is a “moving,” pseudo‐steady‐state hydrate film due to transport of CO2 through the film. The film velocity is dependent of liquid‐liquid diffusivity parameters and reaction constant, and lacking experimental values of these parameters, an order–of‐magnitude analysis is done by fitting the model to experimentally obtained data for the overall film velocity. The motivation for this work is to elucidate options for CO2 depositions in deep oceans, of which liquid CO2 sequestration is believed to be one of the most feasible. Spreading of CO2 from a liquid CO2‐lake and associated lowering of pH in the ecosystem surrounding the lake is of large concern. The work presented here concludes that diffusion of CO2 in the ocean is largely reduced by the hydrate film and suggests that hydrate formation may alleviate some of the environmental concerns regarding deep ocean sequestration of liquid CO2. © 1994 John Wiley & Sons, Inc.
Rates of reaction between the nitrate radical and some aliphatic ethers
Authors: Langer Sarka , Ljungström Evert 
Published: January 2005

AbstractRate coefficients for the reaction of NO3 with dimethyl ether, diethyl ether, di‐n‐propyl ether, and methyl t‐butyl ether (MTBE) have been determined. Absolute rates were measured at temperatures between 258 and 373 K using the fast flow‐discharge technique. Relative rate experiments were also made at 295 K in a reactor equipped with White optics and using FTIR spectroscopy to follow the reactions. The measured rate coefficients (in units of 10−15 cm3 molecule−1 s−1) at 295 K are: 0.26 ± 0.11, 2.80 ± 0.23, 6.49 ± 0.65, and 0.64 ± 0.06 for dimethyl ether, diethyl ether, di‐n‐propyl ether, and methyl t‐butyl ether, respectively. The corresponding activation energies are 21.0 ± 5.0, 17.2 ± 4.0, 15.5 ± 2.1, and 20.1 ± 1.7 kJ mole−1. The error limits correspond to the 95%‐confidence interval. © 1994 John Wiley & Sons, Inc.
Rate constant of the α‐pinene + atomic hydrogen reaction at 295 K
Authors: Vinckier C. , Van Hoof N. 
Published: January 2005

AbstractThe rate constant of the reaction of α‐pinene with atomic hydrogen was determined at 295 K using the fast‐flow reactor technique directly coupled to a mass spectrometric detection technique. The value was found to be equal to (9.8 ± 3.3) × 10−13 cm3 molecules−1 s−1 and independent of the helium pressure between 1 and 2 torr. The major reaction product formed is pinane showing that the stabilization of the adduct radical C10H, followed by a subsequent hydrogen atom addition step, is the important reaction route. © 1994 John Wiley & Sons, Inc.
The determination of kinetic data for the reactions of chromium(VI) with glutathione and other thiols
Authors: Perez‐Benito Joaquin F. , Arias Conchita , Lamrhari Driss , Anhari Abdellah 
Published: January 2005

AbstractThe equations necessary for the determination of the rate constants corresponding to the opposite elementary steps for formation of the oxidant‐reductant ester intermediate, as well as that corresponding to its redox decomposition, in the reduction of chromium(VI) by glutathione and other thiols at physiological pH have been deduced. It is shown that those three rate constants can be obtained with a good reproducibility. © 1994 John Wiley & Sons, Inc.
Spectrokinetic study of SF5 and SF5O2 radicals and the reaction of SF5O2 with NO
Authors: Sehested Jens , Ellermann Thomas , Nielsen Ole John , Wallington Timothy J. 
Published: January 2005

AbstractUV spectra of SF5 and SF5O2 radicals in the gas phase at 295 K have been quantified using a pulse radiolysis UV absorption technique. The absorption spectrum of SF5 was quantified from 220 to 240 nm. The absorption cross section at 220 nm was (5.5 ± 1.7) × 10−19 cm2. When SF5 was produced in the presence of O2 an equilibrium between SF5, O2, and SF5O2 was established. The rate constant for the reaction of SF5 radicals with O2 was (8 ± 2) × 10−13 cm3 molecule−1 s−1. The decomposition rate constant for SF5O2 was (1.0 ± 0.5) × 105 s−1, giving an equilibrium constant of Keq = [SF5O2]/[SF5][O2] = (8.0 ± 4.5) × 10−18 cm3 molecule−1. The SF5O2 bond strength is (13.7 ± 2.0) kcal mol−1. The SF5O2 spectrum was broad with no fine structure and similar to the UV spectra of alkyl peroxy radicals. The absorption cross section at 230 nm was found to (3.7 ± 0.9) × 10−18 cm2. The rate constant of the reaction of SF5O2 with NO was measured to (1.1 ± 0.3) × 10−11 cm3 molecule−1 s−1 by monitoring the kinetics of NO2 formation at 400 nm. The rate constant for the reaction of F atoms with SF4 was measured by two relative methods to be (1.3 ± 0.3) × 10−11 cm3 molecule−1 s−1. © 1994 John Wiley & Sons, Inc.
Dissolution kinetics of copper(II) oxide in water saturated by sulphur dioxide
Authors: Çakici Avni , Çolak Sabri , Eki̇nci̇ Zafer , Bayrakçeken Samih 
Published: January 2005

AbstractThe dissolution and the kinetics of dissolution of cooper(II) oxide in water saturated by sulphur dioxide has been studied. In the experiments, the particle size, the flow rate of the gas, the solid to liquid ratio, and the reaction temperature have been chosen as parameters, while the stirring rate was held constant. As a result of present experiments, it was observed that the decrease of the particle size, the solid to liquid ratio, and an increase of the reaction temperature increased the dissolution rate. It was also observed that the flow rate of sulphur dioxide in the range of its flow rate values did not affect the dissolution rate.The reaction kinetics of copper(II) oxide according to the heterogeneous reaction models was examined and it was found that the dissolution rate was controlled by chemical reaction. The calculated activation energy is 66.50 kJmol−1. © 1994 John Wiley & Sons, Inc.
A novel correlative relationship among rates of complexation of 1:1 copper(II) diketonates and basicity of the ligand
Authors: Verdú Jesus , Blanco Carlos A. 
Published: January 2005

AbstractAn exceptional kinetic behavior on the reactivity of β‐diketones against copper(II) have been found. Some relationship between ligand basicity and unexpected enhancement on the rates of complex formation, which may be useful for predicting rate constants of similar monochelated copper(II) complexes, are established. © 1994 John Wiley & Sons, Inc.
Rates of processes initiated by pulsed laser production of F atoms in the presence of HCl, CH4, and CF3H
Authors: Moore Christopher M. , Smith Ian W. M. , Stewart David W. A. 
Published: January 2005

AbstractTime‐resolved vibrational chemiluminescence from HF has been recorded following the production of F atoms by the pulsed laser photolysis (λ = 266 nm) of F2 in the presence of HCl, CH4, and CF3H. In the first two cases, experiments have been conducted by observing emission from HF(ν = 3) at four temperatures from 295 to 139 K. Rate constants have been determined over this range of temperature for the reactions of F atoms with HCl and CH4 and of CH3 radicals with F2, and for the relaxation of HF(ν = 3) by HCl and CH4. The reaction of F atoms with CF3H is slower than those with HCl and CH4 and measurements on the emission from HF(ν = 2) have been used to infer rate constants for reaction and relaxation only at 295 K. © 1994 John Wiley & Sons, Inc.
Kinetics of esterification of succinic anhydride with methanol by homogeneous catalysis
Authors: Bart H. J. , Reidetschläger J. , Schatka K. , Lehmann A. 
Published: January 2005

AbstractKinetic data on the esterification of succinic anhydride with methanol catalyzed by sulfuric acid have been obtained using a stirred batch reactor. In addition to get a precise ascertainment of the parameters the esterification of monomethyl succinate with methanol has been studied separately. Several experiments have been carried out with different initial molar ratios and different amounts of sulfuric acid at various temperatures. The conversion to dimethyl succinate at 30–65°C follows a first‐order rate expression with respect to each component. A theoretical rate equation is derived by the following reaction mechanism: (1) succinic anhydride is protonated by sulfuric acid to form a reaction intermediate, (2) irreversible esterification to monomethyl succinate, (3) protonation of the monoester, and (4) the esterification to dimethyl succinate proceeds reversibly. The resultant kinetic equation fitted the experimental data quite well and is given by the expression:

© 1994 John Wiley & Sons, Inc. © 1994 John Wiley & Sons, Inc.
Absolute rate constant for the reaction of Phenyl radical with Acetylene
Authors: Yu T. , Lin M. C. , Melius C. F. 
Published: January 2005

AbstractThe absolute rate constant for the reaction of phenyl radical with acetylene has been measured at 20 torr total pressure in the temperature range of 297 to 523 K using the cavity‐ring‐down technique. These new kinetic data could be quantitatively correlated with the data obtained earlier with a relative rate method under low‐pressure (10−3–10−2 torr) and high‐temperature (1000–1330 K) conditions. These kinetic data were analyzed in terms of the RRKM theory employing the thermochemical and molecular structure data computed with the BAC‐MP4 technique.The calculated results reveal that the total rate constant for the C6H5 + C2H2 reaction (kt) is pressure‐independent, whereas those for the formation of C6H5C2H (kb) and the C6H5C2H2 adduct (kc) are strongly pressure‐dependent. A least‐squares analysis of the calculated values for 300–2000 K at the atmospheric pressure of N2 or Ar can be given by

and

all in units of cm3/s. The latter equation effectively represents the two sets of experimental data. © 1994 John Wiley & Sons, Inc.
Oxidation of Arginine by Manganese(III) in Pyrophosphate and Acetate media: A kinetic study
Authors: Chandraju S. , Sherigara B. S. , Gowda N. M. Made 
Published: January 2005

AbstractKinetics of manganese(III) oxidation of L‐arginine has been studied in the presence of pyrophosphate and acetate ions in acidic media at 328 K and 323 K, respectively. The nature of the oxidizing species formed in manganese(III) solutions was determined by spectrophotometric and redox potential measurements. The reaction shows a first‐order dependence on [manganese(III) pyrophosphate] in the pyrophosphate medium, pH 2–3, and a half‐order on [manganese(III) acetate] in HOAc‐acetate medium. In both media, the kinetic order is one with respect to [arginine]. The dependencies of the rate on the reduction product, manganese(II), concentration are zero‐ and inverse first‐orders in acetate and pyrophosphate media, respectively. Effects of varying dielectric constant of the medium and of added anions such as acetate, pyrophosphate, fluoride, chloride, and perchlorate have been investigated, in both media. There is evidence for the existence of free radicals as transient species. Activation parameters have been evaluated using the Arrhenius and Eyring plots. Mechanisms consistent with the observed kinetic data have been proposed and discussed. Kinetic data for the oxidations of some α‐amino acids by manganese(III) species of different forms are summarized and compared. © 1994 John Wiley & Sons, Inc.
Kinetics and mechanism of ruthenium (III) catalyzed oxidation of ethanol by cerium (IV) in aqueous sulfuric acid media
Authors: Das Asim K. , Das Mahua 
Published: January 2005

AbstractThe kinetics of oxidation of ethanol by cerium(IV) in presence of ruthenium(III) (in the order of 10−7 mol dm−3) in aqueous sulfuric acid media have been followed at different temperatures (25–40°C). The rate of disappearance of cerium(IV) in the title reaction increases sharply with increasing [C2H5OH] to a value independent of [C2H5OH] over a large range (0.2–1.0 mol dm−3) in which the rate law conforms to:

where [Ru]T gives the total ruthenium (III) concentration. The values of 10−3kc and 10−3kd are 3.6 ± 0.1 dm3 mol−1 s−1 and 3.9 ± 0.2 s−1, respectively, at 40°C, I = 3.0 mol dm−3. The proposed mechanism involves the formation of ruthenium(III)− substrate complex which undergoes oxidation at the rate determining step by cerium(IV) to form ruthenium(IV)− substrate complex followed by the rapid red‐ox decomposition giving rise to the catalyst and ethoxide radical which is oxidized by cerium(IV) rapidly. The mechanism is consistent with the existence of the complexes RuIII · (C2H5OH) and RuIII · (C2H5O−) and both are kinetically active. The overall bisulphate dependence conforms to: kobsd = A[Ru]T/{1 + C[HSO4−]} where A = 2.2 × 104 dm3 mol−1 s−1, C = 1.3 at 40°C, [H+] = 0.5 mol dm−3, and I = 3.0 mol dm−3. The observations are consistent with the Ce(SO4)2 as the kinetically active species. © 1995 John Wiley & Sons, Inc.
Oxidation of propene in the gas phase
Authors: Stark Moray S. , Waddington David J. 
Published: January 2005

AbstractA series of laboratory and modelling experiments on the oxidation of propene in the gas phase has been undertaken to determine conditions which give high yields of propene oxide. The conditions under which the experiments were conducted were 505–549 K and up to 4 bar pressure. It is proposed that propene oxide is formed from propene by reaction with several peroxy radicals including HO2 and CH3CO3. However, one of the more important radicals is hydroxypropylperoxy. Its reaction with propene, under these conditions
equation image
is more important than concerted decomposition to formaldehyde and acetaldehyde. © 1995 John Wiley & Sons, Inc.
Photo‐induced disproportionation of iodomalonic acid
Authors: RÁBai Gyula , Hanazaki Ichiro 
Published: January 2005

AbstractThe stoichiometry, equilibrium, and kinetics of the photo‐induced disproportionation of iodomalonic acid to I−, I2, and tartronic acid have been studied by means of spectrophotometry and iodide selective electrode at 20.0 ± 0.2°C, pH 2.0–4.0. At pH > 2.9, only I− and HOCH(COOH)2 are detected as major products and the reaction reaches 100% conversion. At pH < 2.9, I2 and malonic acid are also formed and the reaction stops at a conversion rate less than 100%. Both UV (band with a peak at 360 nm) and visible light (480 nm) have been found to be effective. Two primary photochemical processes are identified:
equation image

equation image
While both reactions are sensitive to UV light, only (M2) can be affected by visible light. (M1) and (M2) are considered to initiate a chain reaction sequence in which I· radicals oxidize iodomalonic acid. Dual effects of reaction products on the reaction rate have been observed: while iodine increases the efficiency of visible light and accelerates the reaction, malonic acid inhibits the photo‐decomposition by mediating the recombination of I· radicals to I2. © 1995 John Wiley & Sons, Inc.