bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics of esterification of palmitic acid with isobutyl alcohol on ion‐exchange resin pellets
Authors: Goto Shigeo , Takeuchi Makoto , Matouq Mohamad H. 
Published: January 2005

AbstractCylindrical pellets were made by mixing ion‐exchange resin particles with binding powders and heating to 140°C. To compare catalytic activities of these resin pellets with those of resin particles and sulfuric acid, the esterification of palmitic acid with isobutyl alcohol was carried out in a batch reactor. The rate equation for sulfuric acid could be applied to ion‐exchange resins although the values of parameters were different.
Gas phase thermolysis of aryl t‐butyl amines
Authors: Martin Gonzalo , Ascanio Julian , Rodriguez Jesus 
Published: January 2005

AbstractN‐t‐butylaniline, N‐t‐butyl‐p‐anisidine, and N‐t‐butyl‐p‐nitroaniline have been pyrolyzed in a stirred‐flow reactor at 510–620°C, 8–15 torr total pressure, and 0.5–1.5 s contact time, using toluene as carrier gas. An order one kinetics was observed for the consumption of the amines. The reactions yielded 95 ± 2% isobutene plus the corresponding anilines as reaction products. The rate coefficients followed the Arrhenius equations
N–t–butylaniline

N‐t‐butyl‐p‐anisidine

N‐t‐butyl‐p‐nitroaniline

The results are consistent with an unimolecular elimination of isobutene involving polar four‐center cyclic transition states. © John Wiley & Sons, Inc.
Pulse radiolysis and fourier transform infrared study of neopentyl peroxy radicals in the gas phase at 297 K
Authors: Wallington Timothy J. , Andino Jean M. , Potts Alan R. , Nielsen Ole J. 
Published: January 2005

AbstractThe ultraviolet absorption spectrum of the neopentyl peroxy radical (CH3)3CCH2O2, and the kinetics and products of its self reaction have been studied in the gas phase at 298 K. Absorption cross sections were quantified over the wavelength range 230–290 nm. The measured cross section at 250 nm was;Errors represent statistical (2σ) together with our estimate of potential systematic errors(15%). The kinetics of the decay of the UV absorption following the generation of the neopentyl peroxy radicals was complicated by the rapid decomposition of the (CH3)3CCH2O radicals formed in channel (4a).equation imageBy measuring the yield oft‐butyl peroxy radicals, the branching ratiok4a/(k4a+k4b) was determined to be 0.39 ± 0.03. The rate constant for the self reaction of neopentyl peroxy radicals wask4= (1.07 ± 0.22) × 10−12cm3molecule−1s−1. Quoted errors represent 2σ. These results are discussed with respect to the available literature data. © John Wiley & Sons, Inc.
Kinetics and mechanism of the thermal gas‐phase reaction between NO2 and trichloroethene at 303–362.2 K
Authors: Czarnowski J. 
Published: January 2005

AbstractThe kinetics of the gas‐phase reaction between NO2 and trichloroethene has been investigated in the temperature range 303–362.2 K. The pressure of NO2 was varied betwen 5.1 and 48.7 torr and that of trichloroethene between 7.3 and 69.5 torr. The reaction was homogeneous. Two products were formed: nitrosyl chloride, ClNO, and glyoxyloxyl chloride, HC[O]C[O]Cl, which was identified by its infrared spectrum and its molecular weight determined by chromatography. The rate of consumption of the reactants was independent of the total pressure and can be represented by a second‐order reaction:

The following mechanism was proposed to explain the experimental results:

equation image

The following expression was obtained for k:

. © John Wiley & Sons, Inc.
The kinetics of the reduction of methyl viologen and 9,10‐anthraquinone‐2‐sulfonate by the benzopinacol anion
Authors: Bigger S. W. , Craig R. A. , Grieser F. , Rouch A. J. , Scheirs J. 
Published: January 2005

AbstractThe reduction of methyl viologen (MV2+) and 9,10‐anthraquinone‐2‐sulfonate (AQS) by the benzopinacol anion in 50% (v/v) propan‐2‐ol/water was investigated spectroscopically. The rate constants for these reactions were found to be 12.9 ± 0.2 and 0.23 ± 0.01 M−1 s−1, respectively. © John Wiley & Sons, Inc.
Rate coefficients for the reaction of OH with HONO between 298 and 373 K
Authors: Burkholder James B. , Mellouki Abdelwahid , Talukdar Ranajit , Ravishankara A. R. 
Published: January 2005

AbstractRate coefficients, k1, for the reaction OH + HONO → H2O + NO2, have been measured over the temperature range 298 to 373 K. The OH radicals were produced by 266 nm laser photolysis of O3 in the presence of a large excess of H2O vapor. The temporal profiles of OH were measured under pseudo‐first‐order conditions, in an excess of HONO, using time resolved laser induced fluorescence. The measured rate coefficient exhibits a slight negative temperature dependence, with k1 = (2.8 ± 1.3) × 10−12 exp((260 ± 140)/T) cm3 molecule−1 s−1. The measured values of k1 are compared with previous determinations and the atmospheric implications of our findings are discussed.
An evaluation of the combined application of hammett reaction constant and primary kinetic isotope effects to hydride equivalent transfer reactions
Authors: Srinivasan R. 
Published: January 2005

AbstractBunting et al. have suggested that a combined application of Hammett ρ values (or Brønsted exponents) and primary kinetic isotope effects to hydride equivalent transfer reactions involving 1,4‐dihydronicotinamides and organic oxidants is capable of revealing whether this transfer occurs in a single step or follows a two step e− + H° transfer mechanism (J.W. Bunting, V.S.F. Chew, G. Chu, N.P. Fitzgerald, A. Gunasekara, and H.T.P. Oh, Bioorg. Chem., 12, 141 (1984)). We have used this approach with respect to the reduction of flavins by 1‐substituted 1,4‐dihydronicotinamides. Compelling lines of evidence are presented to demonstrate that this reaction follows the single step hydride transfer mechanism. We also present an analysis of the Brønsted exponent and the primary kinetic isotope effect data for the flavin reaction. It is shown that although a simple application of these parameters does indeed favor the two step e− + H° transfer mechanism for flavin reduction, various other empirical data provide conclusive evidence for the single step hydride transfer mechanism. We attribute this discrepancy to the occurrence of nonequilibrium solvation of the transition state. We have considered several mechanistic complexities which could produce seemingly inconsistent Hammett and primary isotope effect values, and have concluded that these complexities must be considered in interpreting the mechanism of a hydride‐equivalent transfer reaction from kinetic parameters. © John Wiley & Sons, Inc.
Shock tube and modeling study of propene pyrolysis
Authors: Hidaka Yoshiaki , Nakamura Takuji , Tanaka Hiroya , Jinno Akinori , Kawano Hiroyuki , Higashihara Tetsuo 
Published: January 2005

AbstractThe thermal decomposition of propene behind reflected shock waves with 1200 < T5 < 1800 K and 1.6 × 10−5 < ρ5 < 2.7 × 10−5 mol/cm3 was studied by IR laser kinetic absorption spectroscopy and gas‐chromatographic analysis of reaction products. The present data together with earlier shock tube data were satisfactorily modeled with a 51‐reaction mechanism. As the initial step of the reaction, three channels, C3H6 = CH3 + C2H3 (1), C3H6 = H + AC3H5 (2), and C3H6 = CH4 + C2H2 (3), were necessary to interpret all the experimental data. © John Wiley & Sons, Inc.
Acid‐catalyzed hydrolysis of triacylglycerols obeys monoexponential kinetics
Authors: Vega‐ríos Aracelly , Villalobos Heidy , Mata‐segreda Julio F. 
Published: January 2005

AbstractThe acid‐catalyzed hydrolyses of triacetyl‐glycerol and of tributyryl‐glycerol take place following a simple monoexponential kinetic scheme. The result can be interpreted as all three ester groups reacting with approximately the same specific rate. This observation reported in 1920 is unusual, because the intrinsic reactivities of primary and secondary esters are different, and because as far as the reaction proceeds, the remaining ester groups have neighboring hydroxyl groups, which undoubtly alter the reactivity of the reaction centers, relative to the situation in the initial reactant structure. The phenomenom can be explained by considering that local solvation effects due to neighboring hydrophylic groups remain unchanged as the transition‐state complex is formed in all three stages of the reaction. © John Wiley & Sons, Inc.
The thermodynamics and kinetics of the proton‐transfer reactions between bromophenol blue and some aromatic amines in aprotic solution
Authors: Sheridan Peter , Ambroziak Amanda , Fryer Ian , Priest Anna 
Published: January 2005

AbstractThe equilibria and the stopped‐flow kinetics of the reaction between the acid bromophenol blue (BPB) and several aromatic amines in toluene to form ion pairs have been investigated. Contrary to expectations, the rate of the proton‐transfer increases with increasing activation enthalpy. This is explained in terms of the entropy of the transition state.The role of the electronic structure of the amine and of the solvent are discussed. Solvent effects were further investigated by comparing the activation parameters for the reaction between BPB and pyridine in chlorobenzene, toluene, and benzene. The solvent clearly plays a vital role in determining the rate of proton‐transfer via the entropy of activation. The mechanism of the reaction (that proton‐transfer is almost complete in the transition state, and is followed by amine migration and ring opening) is confirmed. © 1993 John Wiley & Sons, Inc.
Discharge‐flow/chemiluminescence and flash‐photolysis/resonance fluorescence studies of the reaction O + SiH4 at room temperature
Authors: Taylor Craig A. , Ding Luying , Marshall Paul 
Published: January 2005

AbstractDF‐CL studies using NO2 chemiluminescence detection of O yielded a rate constant k1 for O + SiH4 of (2.6 ± 0.5)×10−13 cm3 s−1 at 295 K, where the 95% confidence interval reflects accuracy. FP‐RF studies using flash photolysis of SO2 followed by time‐resolved vuv fluorescence detection of O at 295 K yielded k1 = (3.0 ± 0.5) ×10−13 cm3 s−1. These results are in good accord with most previous measurements and lead to a combined best estimate of k1 = (3.2 ± 0.4) × 10−13 cm3 s−1. The DF‐CL and FP‐RF methods appear to have little unrecognized systematic error. © 1993 John Wiley & Sons, Inc.
Kinetics and mechanisms of substitution of the axial and equatorial ligands in an iron(II) macrocyclic heme model complex
Authors: Tomam Henrique E. , Nunes Fabio S. 
Published: January 2005

AbstractThe complex [Fe(imox) (Nmim)2], where imox is a planar bis(iminooxime) macrocyclic ligand and Nmim=N‐methyl imidazole, undergoes substitution reactions in the presence of 2,2′bipyridine (bipy), leading to a series of intermediate mixed complexes. The forward and reverse rate constants for the substitution of the Nmim ligand by water are k1 = 0.23 s−1 and k−1=62 M−1s−1, respectively. The binding of a bipy to the [Fe(imox) (Nmim) (H2O)]+ complex proceeds according to k2 = 4.7×10−2 M−1 s−1 and k−2 = 3.6 × 10−4 s−1, yielding [Fe(imox) (bipy) (Nmim)]+, which eliminates Nmim according to k3 = 1.6 × 10−4 s−1. Further substitution in the [Fe(imox) (bipy)]+ complex with bipy takes place very slowly leading to the [Fe(imox) (bipy)2]+ and [Fe(bipy)3]2+ complexes. © 1993 John Wiley & Sons, Inc.
High temperature pyrolysis of formaldehyde in shock waves
Authors: Hidaka Yoshiaki , Taniguchi Takashi , Kamesawa Takashi , Masaoka Hiromitsu , Inami Koji , Kawano Hiroyuki 
Published: January 2005

AbstractThermal decomposition of formaldehyde diluted with Ar was studied behind reflected shock waves in the temperature range of 1200–2000 K at total pressures between 1.3 and 3.0 atm. The study was carried out for compositions from the concentrated mixture, 4% CH2O, to the highly dilute mixture, 0.01% CH2O by using time‐resolve IR‐laser absorption and IR‐emission, and a single‐pulse technique. From a computer‐simulation study, the mechanism and the rate‐constant expressions that could explain all of our data and previously reported ARAS data were discussed. This data obtained over a wide concentration range from 50 ppm CH2O to 4% CH2O were satisfactorily modeled by a five‐reaction mechanism. © 1993 John Wiley & Sons, Inc.
An evaluation of the kinetic parameters for the reaction of trifluoromethyl radicals with CH3Cl in the gas phase in the temperature range from 416 to 636 K
Authors: Taccone R. A. , Olleta A. , Salinovich O. 
Published: January 2005

AbstractThe hydrogen and chlorine atom abstraction reactions from CH3Cl by CF3 radicals produced by the photolysis of hexafluoroacetone (HFA) and CF3I were studied relative to the recombination of CF3 radicals magnified image
The Arrhenius parameters obtained in the temperature range 416 to 578 K are:

where Θ = 2,303.RT cal mol−1 and k2 is the recombination rate constant for the CF3 radicals.The factors that influence the transfer processes of chlorine and hydrogen are analyzed in a series of reactions of halomethanes with CF3 and CH3 radicals. © 1993 John Wiley & Sons, Inc.
Autoxidation of NO in aqueous solution
Authors: Awad Hani H. , Stanbury David M. 
Published: January 2005

AbstractThe reaction of NO with O2 has been investigated in aqueous solution. As demonstrated by ion chromatography, the sole product is NO2−. Kinetic studies of the reaction by stopped‐flow methods with absorbance and conductivity detection are in agreement that the rate law is ‐d[O2]/dt=k[NO]2[O2] with k = 2.1 × 106 M−2 s−1 at 25°C. This rate law is unaffected by pH over the range from pH 1 to 13, and it holds with either NO or O2 in excess. By studying the reaction over the temperature range from 10 to 40°C, the following activation parameters were obtained: ΔH≠ = 4.6 ± 2.1 kJ mol−1 and ΔS≠=−96 plusmn; 4 J K−1 mol−1. © 1993 John Wiley & Sons, Inc.
Reaction of energetic hydrogen atoms with 1‐chloropropane
Authors: Gould P. L. , Oldershaw G. A. 
Published: January 2005

AbstractThe reaction of photochemically generated energetic hydrogen atoms with 1‐chloropropane, reaction (1),
equation image
has been examined for translational energies of H* in the range 40 to 110 kJ mol−1. Integral probabilities for reaction (1) have been determined, and the phenomenological threshold energy is 47 ± 10 kJ mol−1. The moderating effect of CO2 on reaction (1) for hydrogen atoms of initial energy 108 kJ mol−1 has also been studied. © 1993 John Wiley & Sons, Inc.
Kinetics of Cl(2P) reactions with CF3CHCl2, CF3CHFCl, and CH3CFCl2
Authors: Warren Rachel F. , Ravishankara A. R. 
Published: January 2005

AbstractThe rate coefficients for the removal of Cl atoms by reaction with three HCFCs, CF3CHCl2 (HCFC‐123), CF3CHFCl (HCFC‐124), and CH3CFCl2 (HCFC 141b), were measured as a function of temperature between 276 and 397 K. CH3CF2Cl (HCFC‐142b) was studied only at 298 K. The Arrhenius expressions obtained are: k1 = (3.94 ± 0.84)× 10−12 exp[−(1740 ± 100)/T] cm3 molecule−1 s−1 for CF3CHCl2 (HCFC 123); k2 = (1.16 ± 0.41) × 10−12 exp[−(1800 ± 150)/T] cm3 molecule−1 s−1 for CF3CHFCl (HCFC 124); and k3 = (1.6 ± 1.1) × 10−12 exp[−(1800 ± 500)/T] cm3 molecule−1 s−1 for CH3CFCl2 (HCFC 141b). In case of HCFC 141b, non‐Arrhenius behavior was observed at temperatures above ca. 350 K and is attributed to the thermal decomposition of CH2CFCl2 product into Cl + CH2CFCl. In case of HCFC‐142b, only an upper limit for the 298 K value of the rate coefficient was obtained. The atmospheric significance of these results are discussed. © 1993 John Wiley & Sons, Inc.
Rate constants for the addition of the 2‐hydroxy‐2‐propyl radical to alkenes in solution
Authors: Héberger K. , Fischer H. 
Published: January 2005

AbstractAbsolute rate constants for the addition of the 2‐hydroxy‐2‐propyl radical to 18 substituted alkenes (CH2 = CXY) were determined at (296 ± 1) K in 2‐propanol by time‐resolved electronspin‐resonance spectroscopy. With alkene substitution the rate constants vary by more than 6 orders of magnitude. For 3,3‐dimethyl‐but‐1‐ene the temperature dependence is given by log k/M−1 · s−1 = 6.4 minus;; 19.1/Θ where Θ = 2.303 RT in kJ/mol−1. As shown by a good correlation with the alkene electron affinities, log k296/M−1 · s−1 = 6.46 + 1.71 · EA/eV (r = 0.930), 2‐hydroxy‐2‐propyl is a very nucleophilic radical, and its addition rates are highly governed by polar effects. © 1993 John Wiley & Sons, Inc.
Modelling of the homogeneously catalyzed and uncatalyzed pyrolysis of neopentane: Thermochemistry of the neopentyl radical
Authors: Mitchell T. J. , Benson S. W. 
Published: January 2005

AbstractThe mechanism for neopentane (NpH) pyrolysis in the absence and presence of additives isobutene, HCl and HBr, in the temperature range 750–800 K, has been reinvestigated with the aid of computer simulation and sensitivity analysis techniques. With best values assigned to all rate constants in the kinetic chain, a basic mechanism comprising 18 reversible reactions involving 19 atomic, radical, and molecular species has been used to simulate pure neopentane pyrolysis data. Predictions of major and minor product yields provided quantitative agreement with experimental data against which the model was tested. The mechanism was supplemented by additional species and reactions in order to simulate experimental neopentane pyrolysis data in the presence of HCl and HBr additives. An apparent discrepancy between a recent direct measurement of k5, the rate constant for thermal decomposition of the neopentyl radical [1], and that reported from studies of neopentane pyrolysis in the presence and absence of HCl [2], has been identified as being due to the use of an incomplete mechanism in the latter determination. Simulations of hydrogen halide catalyzed pyrolyses exhibit a high sensitivity to the thermochemical parameters associated with the neopentyl radical (Np). The influence of uncertainties in ΔH(Np) and S(Np) are evaluated and lead to suggested values ΔH(Np) = 8.7 ± 0.8 kcal mol−1 and S(Np) = 78.8 ± 1.0 cal mol−1 K−1. © 1993 John Wiley & Sons, Inc.
Cryochemistry. Large acceleration of the oxidation of hydroxylamine by iodate in frozen solution
Authors: Vajda Tamás 
Published: January 2005

AbstractA large rate increase of the oxidation of hydroxylamine by iodate has been shown in frozen aqueous solution as compared to the supercooled one. The experiments were conducted under frozen conditions at −5°, −10°, −15°, and −20°C and in liquid solution at 0°, −5°, and −10°C, as well. At given time intervals the progress of the reaction was traced by the pH decrease of the unbuffered samples. The around 500‐fold enhanced reaction rate of the frozen samples (at −5° and −10°C) points to an important role of the ice itself beside the increased solute concentration in the compartmentalized heterogeneous system. The contribution of ice to this pH‐regulated oxidation is discussed as a consequence of the high mobility and transfer rate of proton on the ice surface. © 1993 John Wiley & Sons, Inc.
Gas‐phase kinetic study of the silylene addition reaction to acetylene and acetylene‐d2 over the temperature range 291–613 K
Authors: Becerra R. , Walsh R. 
Published: January 2005

AbstractTime‐resolved studies of silylene, SiH2, generated by laser‐flash photolysis of phenylsilane, have been employed to obtain rate constants for its bimolecular reactions with C2H2 and C2D2. The reactions have been studied in the gas‐phase, in the pressure range 1–100 torr (with SF6 bath gas) at five temperatures in the range 291–613 K.Reaction with C2H2 is pressure dependent, consistent with a third body assisted association reaction. However the lack of a simple fit to RRKM calculated values suggests a more complex process with another reaction channel. Reaction with C2D2 is faster than with C2H2, showing a pressure dependent isotope effect. The data are consistent with a rapid isotopic scrambling mechanism. Further RRKM modeling of a three‐channel decomposition mechanism for the suggested silirene adduct (intermediate) provides a semi‐quantitative fit to the data. Rate constants extracted from the modeling are shown to be consistent with a mechanism leading to formation of both ethynylsilane and vinylsilylene, as previously proposed by O'Neal, Ring et al. from higher temperature studies. An enthalpy surface is shown to be consistent with this mechanism. © 1994 John Wiley & Sons, Inc.
Kinetics and mechanisms of the reactions of OH with some oxygenated compounds of importance in tropospheric chemistry
Authors: Saunders S. M. , Baulch D. L. , Cooke K. M. , Pilling M. J. , Smurthwaite P. I. 
Published: January 2005

AbstractThe kinetics of the reactions magnified image have been studied in a discharge flow system under pseudo‐first‐order conditions. The OH concentration was monitored by laser induced fluorescence and helium was used as the carrier gas. Values of k1 = (8.1 ± 1.7) × 10−13, k2 = (1.31 ± 0.26) × 10−11, k3 = (2.6 ± 0.5) × 10−11, and k4 = (2.5 ± 0.4) × 10−11 cm3 molecule−1 s−1, at 298 K and 1 torr total pressure, were obtained.To validate the newly constructed system the rate constant for the reaction magnified image was determined in a similar manner. The value of k5 = (6.7 ± 0.9) × 10−12 cm3 molecule−1 s−1 at 298 K and 1 torr total pressure is in very good agreement with other literature values.The mechanisms for the atmospheric degradation of these compounds have been constructed to allow their incorporation in a photochemical trajectory computer model, to assess their impact on photochemical ozone creation in the troposphere. © 1994 John Wiley & Sons, Inc.
Kinetic studies of the N‐alkylation of secondary amines with 1,2‐dichloroethane
Authors: Yang H. , Thyrion F. C. 
Published: January 2005

AbstractThe reactions of 1,2‐dichloroethane with 2‐(ethylamino)ethanol or diethylamine have been investigated in several solvents from 51 to 80°C. A reaction mechanism has been proposed where 1,2‐dichloroethane reacts with the secondary amines in both bimolecular substitution (SN 2) and elimination (E2) reactions; the substitution product is rapidly converted in an aziridinium ion and undergoes a consecutive reaction with the starting amine to give a tetrasubstituted ethylenediamine. The rate constants as well as the activation energies of these reactions have been determined. © 1994 John Wiley & Sons, Inc.
Kinetic model for hydrocarbon‐assisted particulate boron combustion
Authors: Brown R. C. , Kolb C. E. , Cho S. Y. , Yetter R. A. , Dryer F. L. , Rabitz H. 
Published: January 2005

AbstractA kinetic model is presented to describe the high temperature (1800 K < T < 3000 K) surface oxidation of particulate boron in a hydrocarbon combustion environment. The model includes a homogeneous gas‐phase B/O/H/C oxidation mechanism consisting of 19 chemical species and 58 forward and reverse elementary reactions, multi‐component gas‐phase diffusion, and a heterogeneous surface oxidation mechanism consisting of ‘elementary’ adsorption and desorption reaction steps. Thermochemical and kinetic parameters for the surface reactions are estimated from available experimental data and/or elementary transition state arguments. The kinetic processes are treated using a generalized kinetics code, with embedded sensitivity analysis, for the combustion of a one‐dimensional (particle radius), spherical particle. Model results are presented for the oxidation of a 200 μm boron particle in a JP‐4/air mixture at ambient temperatures of 1400 K and 2000 K. These results include temperature and gas‐phase species profiles as a function of radial distance and particle burning rates. © 1994 John Wiley & Sons, Inc.