bluuebunny/crossref_metadata_2025_split huggingface dataset:
Base catalyzed hydrolysis of Aerosol OT in Aqueous and Aquo‐Dioxane media
Authors: Mukherjee K. , Moulik S. P. , Mukherjee D. C. 
Published: January 2005

AbstractThe OH− ion catalyzed hydrolysis of AOT and sodium mono‐methyl succinate in aqueous and aquo‐dioxane media has been studied. The second‐order rate constant for the former has been found to be nearly ten times slower than that of the latter. At AOT concentrations above CMC, the rate constants become insensitive to the concentration in the studied range of temperature, 25°C–40°C. The activation parameters for the kinetic process have been found to be reasonable, negative entropy of activation has supported a stable transition state complex. A good enthalpy‐entropy compensation of the kinetic process has been found both for AOT and sodium monomethyl succinate in aqueous and aquo‐dioxane media supporting similar nature of the transition state complexes in the hydrolytic reactions. The enthalpies of hydrolysis of AOT and the half ester of succinic acid in aqueous and aquo‐dioxane media have been also reported. © 1994 John Wiley & Sons, Inc.
Catalytic activity of Manganese(II)‐Gluconate complex in reactions of Hydrogen Peroxide
Authors: Rocha Cleonice , Da Costa Ferreira Ana Maria 
Published: January 2005

AbstractKinetic studies of the hydrogen peroxide decomposition catalyzed by the dimeric Mn(II)‐gluconate complex, in alkaline medium, showed evidence for the oxidative cleavage of the ligand, leading to the formation of formaldehyde as one of the products. In the presence of a large excess of other hydroxylated substrates, such as methanol or ethylene glycol, a significant increase in the yield of formaldehyde was observed, corroborating the observed peroxidase activity in this system, in addition to the catalase activity. Oxygen free radicals were detected as intermediates of reaction, by ESR spectroscopy using the spintrapping method, only under aerobic conditions. Therefore, a nonradical mechanism was proposed for the reaction, based on the formation of a peroxo‐Mn(II) complex, and its further reduction to the previous Mn(II) species. © 1994 John Wiley & Sons, Inc.
The nitrosation of Amino Acids
Authors: Gil Rafael , Casado Julio , Izquierdo Carmen 
Published: January 2005

AbstractWith a view to clarifying analogies and differences between the mechanisms involved in the nitrosation of amino acids and secondary amines, we studied the kinetics of the nitrosation of five imino acids (azetidine‐2‐carboxylic acid, pyrrolidine‐2‐carboxylic acid, piperidine‐2‐carboxylic acid, piperidine‐3‐carboxylic acid, and piperidine‐4‐carboxylic acid) and of the ethyl esters of three of them. Reaction kinetics were determined by the initial rate method, by spectrophotometric monitoring of the concentration of nitroso amino acid formed. The presence of the COO− group in the amino acids opens a new mechanistic route for the nitrosation of the secondary amino group: a nitrosyl carboxylate formed initially acts as an internal nitrosating agent, resulting in intramolecular migration of N  O from the carboxylate group to the secondary amino group. The observed order of the α−, β−, and γ‐amino acids as regards the ease of N‐nitrosation by this route is explained in terms of the relative energies of (a) the equatorial and axial orientations of the CringCcarboxyl bond, and (b) the chair and boat forms of the piperidine ring. © 1994 John Wiley & Sons, Inc.
Kinetics of the 1,5‐dipolar cyclization of 2‐Vinylpyridinium ylides to Indolizines. Determination of rate parameters by laser flash photolysis
Authors: Liu Michael T. H. , Romashin Yuri N. , Bonneau Roland 
Published: January 2005

AbstractNanosecond laser flash photolysis (λ = 355 nm) of an aqueous solution of 3‐chloro‐3‐p‐chlorophenyldiazirine in isooctane produces a transient absorption at 310 nm due to the formation of the carbene. In the presence of 2‐vinylpyridine, a second transient with a broad absorption band peaking at 520 nm grows in. This absorption is attributed to 2‐vinylpyridinium ylide. The ylide decays with a lifetime equal to 33 µs at 25°C independent of the concentration of 2‐vinylpyridine. As the ylide decays, there is a concomitant growth of an absorption at 330 nm, attributed to the formation of inodolizine. The activation parameters for the 1,5‐dipolar cyclization of the ylide to indolizine were determined; Ea = 12.1 kcal mol−1 and log A = 13.4. © 1994 John Wiley & Sons, Inc.
Kinetics and mechanism of electron transfer reactions in aqueous solutions: Silver(I) catalyzed oxidation of aspartic acid by cerium (IV) in acid perchlorate medium
Authors: Sharma Indu , Devra Vijai , Gupta Divya , Gangwal C. M. , Sharma P. D. 
Published: January 2005

AbstractSilver(I) catalyzed oxidation of aspartic acid by cerium(IV) was studied in acid perchlorate medium. The stoichiometry of the reaction is represented by the eq. (i)equation imageDimeric cerium(IV) species has been indicated and employed in calculations of monomeric cerium(IV) species concentrations. The reaction is second‐order and uncatalyzed reaction also simultaneously occurs along with the silver(I) catalyzed reaction conforming to the rate law (ii)equation imagewherekis an observed second‐order rate constant. A probable reaction mechanism is suggested. © 1995 John Wiley & Sons, Inc.
Kinetics and mechanism of ligand substitution in binuclear nickel(II) and cobalt(II) complexes
Authors: Hynes Michael J. , Doody Marie T. 
Published: January 2005

AbstractThe kinetics and mechanism of the removal of M2+ from bis‐(heptane‐2,4,6‐trionato)M(II) [M = Ni, Co] by ethylenediminetetraacetic acid (EDTA), nitrilotriacetic acid (NAT), 1,2‐cyclohexanediamine‐N, N, N′, N′‐tetraacetic acid (CyDTA), and ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA) have been investigated using stopped‐flow spectrophotometry in methanol‐water at 25°C and ionic strength 0.1 mol dm−3 KNO3. The reactions were investigated at a number of different pHs.An associative mechanism is proposed to account for the kinetic data. Although all the ligands have similar functional groups, their reactivity towards the parent complex is quite different. The pH dependence of the rate constants has been used to determine the relative reactivities of the various ligand species present. In the case of nitrilotriacetic acid, a nonlinear dependence on ligand concentration is observed, thus confirming the mechanism proposed. © 1995 John Wiley & Sons, Inc.
Oxidative cleavage of S‐arylmercaptoacetic acids by sodium perborate: Kinetic and correlation study
Authors: Kabilan S. , Pandiarajan K. , Krishnasamy K. , Sankar P. 
Published: January 2005

AbstractKinetics of oxidation of twenty six S‐arylmercaptoacetic acids (SAMA) (I) by sodium perborate (PB) have been studied in acid medium. The product of oxidation is the corresponding thiophenol. The rate data of meta‐and para‐substituted acids have been correlated with DSP equations. While the para‐compounds correlate well with σI and σR° values, the meta‐compounds correlate well with σI and σ values. The reaction constants are negative and of smaller magnitudes. Further, the ortho‐substituted acids show a good correlation with a triparametric equation involving Taft's σI and R° and Charton's steric parameter ν. There is a considerable steric contribution to the total ortho‐substituent effect. Based on these observations, mechanism involving the formation of protonated arylsulfinylacetic acid intermediate, followed by an intramolecular rearrangement leading to the product thiophenol has been proposed. © 1995 John Wiley & Sons, Inc.
Temperature and pressure effects on the kinetics of the Bromate ion‐iodide ion‐L‐ascorbic acid clock reaction
Authors: Fábián István , Van Eldik Rudi 
Published: January 2005

AbstractThe kinetics of the bromate ion‐iodide ion‐L‐ascorbic acid clock reaction was investigated as a function of temperature and pressure using stopped‐flow techniques. Kinetic results were obtained for the uncatalyzed as well as for the Mo(VI) and V(V) catalyzed reactions. While molybdenum catalyzes the BrO‐I− reaction, vanadium catalyzes the direct oxidation of ascorbic acid by bromate ion. The corresponding rate laws and kinetic parameters are as follows. Uncatalyzed reaction: r2 = k2[BrO] [I−][H+]2, k2 = 38.6 ± 2.0 dm9 mol−3 s−1, ΔH‡ = 41.3 ± 4.2 kJmol−1, ΔS‡ = −75.9 ± 11.4 Jmol−1 K−1, ΔV‡ = −14.2 ± 2.9 cm3 mol−1. Molybdenum‐catalyzed reaction: r′2 = k2[BrO] [I−] [H+]2 + kMo[BrO] [I−] [ H+]2[M0(VI)], kMo = (2.9 ± 0.3)106 dm12 mol−4 s−1, ΔH‡ = 27.2 ± 2.5 kJmol−1, ΔS‡ = −30.1 ± 4.5 Jmol−1K−1, ΔV‡ = 14.2 ± 2.1 cm3 mol−1. Vanadium‐catalyzed reaction: r′1 = kV[BrO] [V(V)], kV = 9.1 ± 0.6 dm3 mol−1 s−1, ΔH‡ = 61.4 ± 5.4 kJmol−1, ΔS‡ = −20.7 ± 3.1 Jmol−1K−1, ΔV‡ = 5.2 ± 1.5 cm3 mol−1. On the basis of the results, mechanistic details of the BrO‐I− reaction and the catalytic oxidation of ascorbic acid by BrO are elaborated. © 1995 John Wiley & Sons, Inc.
Kinetics of hydrogen peroxide decomposition with Fe(III) and Cr(III)‐ethanolamines complexes sorbed on dowex‐50W resin
Authors: Salem Ibrahim A. 
Published: January 2005

AbstractThe kinetics of the H2O2 decomposition in presence of Fe(III)‐ and Cr(III)‐complexes of mono‐, di‐, and triethanolamine supported on Dowex‐50W resin have been investigated. The decomposition process proceeded with first‐order kinetics for the substrate concentration. The rate of reaction increased with increasing number of the coordinated ligands in the metal complex as well as with increasing ligand basicity. The decomposition reaction involved the formation of an intermediate active species, which converts into a peroxo‐metal complex of brown, green, or gray color. A mechanism describing the decomposition process is proposed. © 1995 John Wiley & Sons, Inc.
Specific interactions in reversed micelles: Oxidation of Fe(bpy)32+ by S2O82− in AOT‐oil‐water microemulsions
Authors: LóPez Pilar , RodríGuez Amalia , GóMez‐Herrera Carlos , SáNchez Francisco , Moyá Marí Luisa 
Published: January 2005

AbstractThe oxidation of Fe(bpy)22+ by peroxodisulphate (bpy = 2,2′‐bipyridine) has been studied in a variety of sodium bis(2‐ethylhexyl)sulfosuccinate(aerosol‐OT or AOT)‐oil‐water microemulsions by changing the nature of the oil phase, the surfactant concentration, and the molar ratio w = [H2O]/[AOT]. Kinetic results show that the influence of surfactant concentration is due to a dilution effect. On the other hand, the comparison between the reaction rate in conventional aqueous solution with that in AOT w/o microemulsions seems to indicate that the iron(II) species is distributed between the aqueous phase and the interphase. © 1995 John Wiley & Sons, Inc.
Kinetics on the dissolution of CO2 into water from the surface of CO2 hydrate at high pressure
Authors: Shindo Yuji , Fujioka Yuichi , Takeuchi Kazuhisa , Komiyama Hiroshi 
Published: January 2005

AbstractKinetic study on the dissolution of CO2 from the surface of a liquid CO2 droplet in water was conducted, and a mechanism of the decay of CO2 hydrate was proposed. The model was applied to the experimental data which showed that the radius of liquid CO2 droplets in water reduced linearly with time. It was proved that the dissolution rate of CO2 into water is dominated by the decay of CO2 hydrate on the surface of the droplet. The rate constant of the decay of CO2 hydrate was estimated to be 1.25 × 10−6 m s−1. From a viewpoint of liquid CO2 disposal in the deep ocean, it is predicted that the thin membrane of CO2 hydrate at the interface between seawater and liquid CO2 will control the dissolution of CO2 into seawater. © 1995 John Wiley & Sons, Inc.
Oxidation of thiosulfate by manganese(III) and nickel(III) complexes: A kinetic and mechanistic investigation
Authors: Dutta Amitava , Ali Mahammad , Gangopadhyay Sumana , Banerjee Pradyot 
Published: January 2005

AbstractThe kinetics of the oxidation of thiosulfate ion by [Mn(Y)]− (H4Y = trans‐cyclohezane‐1,2‐dimine‐N,N,N′,N′‐tetraacetic acid) and [Ni(L1)]2+ (HL1 = 15‐amino‐3‐methyl‐4,7,10,13‐tetraazapentadec‐3‐en‐2‐one oxime) have been investigated at 20.0, 30.0, and 40.0°C in aqueous solution and found to follow the general rate law −d/dt [complex] = kox[S2O32−] [complex]. The large negative entropy (ΔS‡) of activation for the reactions and the results of Marcus calculation provide support for inner‐sphere mechanism to be operative. © 1995 John Wiley & Sons, Inc.
Kinetics of the autocatalytic oxidation of N‐amino‐3‐azabicyclo[3,3,0]octane by chloramine in aqueous medium
Authors: El Khatib M. , Marchand A. , Counioux J. J. , Delalu H. 
Published: January 2005

AbstractThe kinetics of the degradation of N‐amino‐3‐azabicyclo[3,3,0]octane by chloramine has been studied by GC and HPLC in stoichiometric conditions in a solution buffered with NaOH/KH2PO4 and Na2B4O7.10 H2O between pH = 10.5 and 13.5. The second‐order reaction exhibits specific acid catalysis which indicates competitive oxidation between the haloamine and the neutral and ionic forms of the bicyclic hydrazine. The enthalpy and entropy of activation were determined at pH = 12.89.In a nonbuffered solution, the interaction is autocatalyzed due to acidification of the mixture by the ammonium ions. In basic medium, the reaction forms an endocyclic hydrazone. A mathematical treatment based on an implicit equation allows a quantitative interpretation of all the phenomena observed over the above pH interval. This takes both the acid/base dissociation equilibria and the alkaline hydrolysis of the chloro‐derivative into account. © 1995 John Wiley & Sons, Inc.
Thermolysis reaction of 2‐acetyl‐1‐oxo‐five‐, six‐, and seven‐membered ring
Authors: Al‐Awadi Nouria A. , Mathew Tommy 
Published: January 2005

AbstractThe rates of gas‐phase thermolysis reactions of 2‐acetylcyclopentanone 1,2‐acetylcyclohexanone 2, N‐acetylcaprolactam 3,2‐acetylbutyrolactone 4,2‐acetyl‐2‐methylbutyrolactone 5, and 3‐acetyl‐2‐oxazolidinone 6 have been measured over a temperature range of 50 K. They undergo unimolecular first‐order elimination reactions for which log A = 11.7, 11.7, 11.2, 11.4, 11.5, and 11.1 s−1 and Ea = 193.4, 189.5, 153.2, 201.0, 206.8, and 176.1 kJ mol−1, respectively. The effect of the ring size together with the effect of a heteroatom in the ring on the rate of thermolysis reactions for compound 1–6 is the subject of this work. © 1995 John Wiley & Sons, Inc.
The gas‐phase elimination kinetics of 2‐hydroxy‐2‐methylbutyric acid and 2‐ethyl‐2‐hydroxybutyric acid
Authors: Chuchani Gabriel , Martin Ignacio , Rotinov Alexandra 
Published: January 2005

AbstractThe elimination kinetics of the title compounds have been examined over the temperature range of 270–320°C and pressure range of 19–117 torr. The reactions, carried out in seasoned vessels, with the free‐radical suppressor toluene always present, are homogeneous, unimolecular, and follow a first‐order rate law. The products of 2‐hydroxy‐2‐methylbutyric acid are 2‐butanone, CO, and H2O; while of 2‐ethyl‐2‐hydroxybutyric acid are 3‐pentanone, CO, and H2O. The rate coefficient is expressed by the following Arrhenius equation: for 2‐hydroxy‐2‐methylbutyric acid, log k1(s−1 = (12.87 ± 0.19) − (171.2 ± 2.1) kJ mol−1 (2.303 RT)−1; and for 2‐ethyl 2‐hydroxybutyric acid, log k1s−1) = (12.13 ± 0.34) − (159.4 ± 3.7) kJ mol−1 (2.303 RT)−1. Augmentation of alkyl bulkiness at the 2‐position of the 2‐hydroxycarboxylic acids showed an increase in the rate of dehydration. The electron release of alkyl groups, rather than steric acceleration, appears to enhance the pyrolysis decomposition of these substrates. These reactions are believed to proceed through a semi‐polar five‐membered cyclic transition type of mechanism. © 1995 John Wiley & Sons, Inc.
Kinetic modeling of the CH3 + C2H2 reaction data with sensitivity analyses
Authors: Diau Eric W. , Lin M. C. 
Published: January 2005

AbstractKinetic modeling and sensitivity analyses for the reaction CH3 + C2H2 → CH3C2H2 (4) have been performed according to the experimental conditions and results of Mandelcorn and Steacie, Garcia Dominguez and Trotman–Dickenson, and Holt and Kerr. The kinetically modeled results show that Mandelcorn and Steacie overestimated the rate constant of reaction (4) whereas Garcia Dominguez and Trotman‐Dickenson underestimated it, and that there could be significant uncertainty in the steady‐state treated results of Holt and Kerr. Reanalysis of Garcia Dominguez and Trotman–Dickenson's experimental data by kinetic modeling with the proper mechanism gives a more reliable rate constant for reaction (4). The improved rate constant (k4) is in good agreement with our theoretically predicted values. © 1995 John Wiley & Sons, Inc.
Thermal reduction of NO by H2: Kinetic measurement and computer modeling of the HNO + NO reaction
Authors: Diau Eric W. , Halbgewachs Melissa J. , Smith Anita R. , Lin M. C. 
Published: January 2005

AbstractThe kinetics and mechanism of the thermal reduction of NO by H2 have been investigated by FTIR spectrometry in the temperature range of 900 to 1225 K at a constant pressure of 700 torr using mixtures of varying NO/H2 ratios. In about half of our experimental runs, CO was introduced to capture the OH radical formed in the system with the well‐known, fast reaction, OH + CO → H + CO2. The rates of NO decay and CO2 formation were kinetically modeled to extract the rate constant for the rate‐controlling step, (2) HNO + NO → N2O + OH. Combining the modeled values with those from the computer simulation of earlier kinetic data reported by Hinshelwood and co‐workers (refs. [3] and [4]), Graven (ref.[5]), and Kaufman and Decker (ref. [6]) gives rise to the following expression:

.This encompasses 45 data points and covers the temperature range of 900 to 1425 K. RRKM calculations based on the latest ab initio MO results indicate that the reaction is controlled by the addition/stabilization processes forming the HN(O)NO intermediate at low temperatures and by the addition/isomerization/decomposition processes producing N2O + OH above 900 K. The calculated value of k2 agrees satisfactorily with the experimental result. © 1995 John Wiley & Sons, Inc.
The decomposition of nitrous oxide at 1.5 ⩽ P ⩽ 10.5 atm and 1103 ⩽ T ⩽ 1173 K
Authors: Allen Mark T. , Yetter Richard A. , Dryer Frederick L. 
Published: January 2005

AbstractReaction experiments on mixtures of N2O/H2O/N2 were performed in a variable pressure flow reactor over temperature, pressure, and residence time ranges of 1103–1173 K, 1.5–10.5 atm, and 0.2–0.8 s, respectively. Mixtures of approximately 1% N2O in N2 were studied with the addition of varying amounts of water vapor, from background to 3580 ppm. Experimentally measured profiles of N2O, O2, NO, NO2, H2O, and temperature were compared with predictions from detailed kinetic modeling calculations to assess the validity of a reaction mechanism developed from currently available literature thermochemical and rate constant parameters. Sensitivity and reaction flux analyses were performed to determine key elementary reaction path processes and rates.Reaction rate constants for the uni‐molecular reaction, N2O → N2 + O, were determined at various pressures in order to match overall experimental and numerical decomposition rates of N2O. The numerical model included a newly determined rate constant for N2O + OH → HO2 + N2 with an upper limit of 5.66 × 108 cm3 mol−1 sec−1 at 1123 K. This is considerably smaller than presently reported in the literature. The experimentally observed rate of N2O decomposition was found to be slightly dependent on added water concentration. The rate constant determined for the elementary decomposition is strongly dependent on the choice of rate constants for the N2O + O ⇔ N2 + O2 and N2O + O ⇔ NO + NO reactions. In the absence of accurate data at the temperatures of this work, and based on these and other experiments in this laboratory, we presently recommend rate constants from the review of Baulch et al. The basis for this recommendation is discussed, including the impact on the rate constants derived for elementary nitrous oxide decomposition. The uncertainties in the rate constants as reported here are ±30%.The present mechanism was applied to previously reported high‐pressure shock tube data and yields a high‐pressure limit rate constant a factor of three larger than previously reported at these temperatures. The following expressions for the elementary decomposition reaction are recommended: k = 9.13 × 1014 exp (−57, 690/RT) cm3 mol−1 s−1 and k∞ = 7.91 × 1010 exp(−56020/RT) s−1. Simple Lindemann fits utilizing these parameters reproduce the pressure dependent rate constants measured here within ±25%. © 1995 John Wiley & Sons, Inc.
Stepwise mechanisms of the aminolyses of 4‐Nitrophenyl and 2,4‐Dinitrophenyl O‐Ethyl Dithiocarbonates in aqueous Ethanol
Authors: Castro Enrique A. , MuñOz Gabriel , Salas Mirtha , Santos Jose G. 
Published: January 2005

AbstractThe reactions of the title substrates with a series of secondary alicyclic amines are subjected to a kinetic study in 44 wt% aqueous ethanol, at 25.0deg;C, ionic strength 0.2 M (maintained with KCl). Pseudo‐first‐order kinetics are found under amine excess. The order in amine obtained is one in the reactions of all amines. The Brönsted‐type plots for the overall second‐order rate coefficients are biphasic with slopes β1 = 0.3 (high pKa), β2 = 0.95 (low pKa) for the aminolysis of the 4‐nitro derivative, and β1 = 0.3 and β2 = 0.80 for the aminolysis of the dinitro compound; the pKa values at the curvature center are pK = 9.8 and 9.5, respectively. From a comparison of these pK values with those found in the same reactions in water and the shapes of the Brönsted‐type plots, it is concluded that these reactions are stepwise, with the formation of a zwitterionic tetrahedral intermediate in the reaction pathway. © 1995 John Wiley & Sons, Inc.
Oxidation of malic acid by vanadium (V) in sulphuric acid medium: A kinetic and mechanistic investigation
Authors: Ziglio Cláudio Marcos , Takashima Keiko 
Published: January 2005

AbstractThe oxidation kinetics of malic acid by vanadium(V) in aqueous sulphuric acid was investigated at 303 K by monitoring the appearance of vanadium(IV) at 760 nm. The reaction showed first‐order behavior with respect to vanadium(V), malic acid, and hydrogen ion concentration, respectively, regardless of the ionic strength. The reaction rate is enhanced by an increase in ionic strength and a decrease of the dielectric constant of the medium by addition of methanol. The activation parameters were estimated by varying the temperature in the range of 293 K to 313 K to 313 K. An oxidation mechanism is proposed, involving different vanadium(V) species produced in the presence of sulphuric acid. © 1995 John Wiley & Sons, Inc.