bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rate constant for H+H+Ar = H2 + Ar from 1300 to 1700 K
Authors: Mallard W. G. , Owen J. H. 
Published: January 2005

AbstractShock tube experiments on the decay of OH‐radical concentration after shock‐initiated combustion of H2:O2:Ar = 10:1:89 mixtures were analyzed to give the rate constant 1 × 1015 cm6mol−2s−1for the reaction H + H + Ar = H2 + Ar overthe temperature range 1300 to 1700 K.
The temperature dependence of vibration–vibration energy exchange between CO and COS
Authors: Richman Dennis C. , Lev‐on Miriam , Millikan Roger C. 
Published: January 2005

AbstractThe present study reports the measurement of the V–V energy transfer rates for the CO*COS system in the temperature range of 195 to 370°K. The measured rates exhibit a slight inverse temperature dependence. The experimental results are compared to prediction based on a model of long‐range dipole–dipole interactions between colliding molecules. The effect of single quantum rotational transitions is compared to that of multiquantum rotational transitions.
Absolute rate constants for the reactions O(3P) atoms with HCl and HBr
Authors: Brown Raymond D. H. , Smith Ian W. M. 
Published: January 2005

AbstractA flow tube method has been used to determine rate constants for the elementary reactions:
equation image
Oxygen atoms were produced by adding a small excess of NO to a stream of partially dissociated nitrogen, and their reaction with hydrogen halide was monitored by observing the intensity of the NO + O afterglow. Experiments were carried out at temperatures from 293 to 440°K with HCl, and from 267 to 430°K with HBr. The role of secondary reactions was minimised and the residual effects were allowed for. The rate constants for the primary reactions could be matched by Arrhenius expressions:

where the units are cm3/molec·sec and the errors correspond to a standard deviation.
The kinetics of the Diels–Alder addition of cyclopentadiene to acetylene and the decomposition of norbornadiene
Authors: Walsh Robin , Wells Jean M. 
Published: January 2005

AbstractThe title reactions have been investigated in a static system. The addition of acetylene to cyclopentadiene (CPD) results in formation of norbornadiene (BCH), cycloheptatriene (CHT), and toluene (T), while BCH decomposition produces CPD, C2H2, CHT, and T. Kinetic studies, comprising both product–time evolution and initial pressure variation, support a mechanism
equation image
These reactions are almost certainly homogeneous and molecular in nature. Least mean square analysis of the data yield for temperatures of 525–656°K, log k−1 (1./mole·s)=7.51±0.05−	(24.19±0.15 kcal/mole)/RT ln 10, and for temperatures of 584–630°K,
Kinetics and mechanism of the pyrolysis of pentachloroethane
Authors: Houser Thomas J. , Cuzcano Teodomiro 
Published: January 2005

AbstractThe rate of the inhibited pyrolysis of pentachloroethane was studiedover the temperature range of 820 to 865°K using the toluene‐carrier technique in a stirred‐flow reactor. The pyrolysis rate was found to be first order in reactant, and the rate constant is described by k=1011.6±0.7 exp [(−48,200±2600)/RT] sec−1. An increase by a factor of 6.6 in the surface/volume of the reactor had a negligible effect on the rate. This observation, in addition to a reevaluation of earlier kinetic data for the pyrolysis of pentachloroethane, lead to the following conclusions concerning the pyrolysis mechanism. The initiation and termination as well as the propagation reactions were homogeneous, the termination involved both Cl and C2Cl5 radicals (crosstermination), and autocatalysis was caused by interaction between chlorine and pentachloroethane rather than by dissociation of molecular chlorine.
The Influence of solvent and crown polyethers on the nucleophilic reactivity of potassium tert‐Butylperoxide, potassium tert‐Butoxide, and some other oxygen bases
Authors: Curci Ruggero , di Furia Fulvio 
Published: January 2005

AbstractThe rates of reaction of t‐BuOOK, t‐BuOK, n‐BuOOK, and p‐MeC6H4OKwith p‐nitrophenyl diphenylphosphinate 1 and with p‐nitrophenyl benzoate 2 have been measured in toluene both in the absence and in the presence of crown polyether dicyclohexyl‐18‐crown‐6 3a. The rates of nucleophilic displacementon 1 by HOO−, t‐BuOO−, and some “nonalpha” oxyanions in water have also been determined. Solvent transfer from water to toluene results in increasing the nucleophilic reactivity of the t‐butyl hydroperoxide anion. Rate ratios QQa are given which allow one to estimate the enhanced reactivity of t‐BuOO− (an α‐nucleophile) compared to oxygen nucleophiles of comparable base strength toward 1 and 2. These are for substrate 1, Qα (water) ≃ 6.5 and Qα (toluene) ≃ 2.7; for substrate 2, Qα (water) ≃ 5.5 and Qα (toluene) ≃ 5. The hypothesis is advanced that solvation is not a major factor in determining the α‐effect of the t‐butylhydroperoxide anion.
Rate constants for the decarboxylation of the t‐butoxicarbonyl radical and concurring radical terminations directly obtained by kinetic ESR
Authors: Rüegge D. , Fischer H. 
Published: January 2005

AbstractRate constants of various simultaneous reactions of t‐butoxicarbonyl and t‐butyl radicals generated by photolysis of t‐butylpivalate in n‐heptane are directly determined by kinetic electron spin resonance. The temperature dependence of the decarboxylation reaction t‐BuOĊO → t‐Bu. + CO2 obeys log )K/S−1( = 13.8−49.0/θ where θ = 2.303 RT/kJ . mol−1. The self‐ and cross‐termination of the radicals are diffusion limited.
Kinetics and mechanism of the explosive reaction of carbon monoxide and oxygen
Authors: Ahmed S. , Back M. H. 
Published: January 2005

AbstractA new technique is described for quantitative measurement of the conditions of reactant concentration at ignition in mixtures of carbon monoxide and oxygen. A thin film of carbon covering the surface of a quartz reaction vessel reacted with oxygen to form carbon monoxide and small quantities of water. Explosions were observed above 900 K over the pressure range 15–100 torr with ratios of CO/O2 far below those hitherto explored. The onset of explosion was favored by the addition of hydrogen, methane, and water and was inhibited by the addition of inert gases. A simple mechanism predicts the occurrence of an explosion over a wide range of product composition and total pressure.
The intimate ion pair mechanism in the maximally inhibited elimination kinetics of methyl 4‐chlorobutyrate and methyl 5‐chlorovalerate in the gas phase
Authors: Chuchani Gabriel , Dominguez Rosa M. , Rotinov Alexandra 
Published: January 2005

AbstractThe gas phase elimination of methyl 4‐chlorobutyrate and methyl 5‐chlorovalerate has been reexamined, in a static system and seasoned vessel, over the temperature range of 419.6–472.1°C and pressure range of 45–108 torr. The reactions, under maximum inhibition with propene, are homogeneous, unimolecular, and obey a first‐order rate law. The rate coefficients are given by the following Arrhenius equations: for methyl 4‐chlorobutyrate, log (k1(s−1) = (13.41 ± 0.60) ‐ (226.8 ± 8.2) kJ/mol/2.303RT; and for methyl 5‐chlorovalerate, log k1(s−1) = (13.20 ± 0.02) ‐ (227.6 ± 0.3) kJ / mol / 2.303RT. The pyrolysis rates are found to be about a half of the rates reported in a previous work. As already advanced, the carbomethoxy substituent appears to provide anchimeric assistance in the elimination process, where normal dehydrochlorination and lactone formation arise from an intimate ion pair type mechanism. The partial rates towards each of these products have been determined and reported.
Effects of alkenes on the thermal decomposition of propane part II. Influence of ethylene
Authors: Dombi A. , Huhn P. 
Published: January 2005

AbstractExperiments with propane‐ethylene mixtures in the temperature range 760–830 K resulted in refinement of the role of ethylene inhibition in the decomposition of propane. The source of the rate‐reducing effect of ethylene is the reaction
equation image
This replaces the decomposition chains more slowly by means of the reactions
equation image

equation image

equation image
than H‐atoms do by direct H‐abstraction from propane. Analysis of the ratios of the product formation rates showed that the selectivity of the ethyl radical for the abstraction of hydrogen of different bond strengths from propane was practically the same as that of the H‐atom. The ratio of the rate constants of hydrogen addition to ethylene and methyl‐hydrogen abstraction from propane by the H‐atom (3) was determined

as was that of the decomposition and the similar H‐abstraction of the ethyl radical

Interpretation of the influence of ethylene required the completion of the mechanism with further initiation of the reaction
equation image
besides termination via ethyl radicals.
Linearization of second‐order reaction data
Authors: Livesey D. L. 
Published: January 2005

AbstractReaction data described by the second‐order growth function A(t) = A∞(αt) (1 + αt)−1, where A∞ is the ultimate value of the product concentration A(t), can be linearized by plotting a suitable function F(t) against the time (t). The slope of the straight line obtained is (2α), where α is the product of the rate constant (k2) and the initial concentration of either reactant, with the result that k2 can be determined without knowledge of Aϰ. Optimal determination of the parameter α requires that data taking be limited to the interval 0 ≤ t ≤ T, where (αT) is approximately 4.0. Numerical data derived from an experiment on the exchange of lead by zinc ions in the enzyme carbonic anhydrase are analyzed to illustrate the method. The effects of small errors in the initial concentrations and of small deviations from second‐order kinetics are briefly discussed.
Kinetics and mechanism of the reaction between thiosulfate and chlorite ions at 90°C
Authors: Nagypál István , Epstein Irving R. , Kustin Kenneth 
Published: January 2005

AbstractThe kinetics of the oxidation of S2O32− by ClO2− have been studied in aqueous alkaline solution at 900C using classical titrimetric methods to follow the course of the reaction. The reaction takes place according to the stoichiometry S2O32− + 2ClO2− + 2OH− = 2SO42− + 2Cl− + H2O even in large S2O32− excess. There is some indication of a complex reaction pattern, but 70% of the ClO2− disappearance can be best described by the autocatalytic rate equation ‐d[ClO2−]/dt = k[S2O32−] [ClO2−] [H+] with k = (1.3 ± 0.2) ×108 M−2 sec−1. The mechanism is explained by postulating nucleophilic attack of S2O32− on HClO2 to form a chlorine‐containing intermediate.
Base‐catalyzed tritium exchange between tritium‐containing heavy water and deuterated chloroform–kinetics and equilibrium
Authors: Maienschein Jon L. , Barry Patrick E. 
Published: January 2005

AbstractWe develop a kinetic model for the exchange of tritium and deuteriumbetween tritium‐containing heavy water and deuterated chloroform in a two‐phase liquid system, catalyzed by hydroxide ion (sodium hydroxide). For the exchange reaction yielding tritiated chloroform andheavy water, the measured equilibrium constant is 0.518 at 25–45°C, independent of temperature. The rate constant (for the controlling step, deuteron abstraction from chloroform) is 0.22 L/mol s at 25°C, 0.72 at 35°C, and 2.0 at 45°C, corresponding to an activation energy of 87 kJ/mol. Comparison is made with literature data, and effects of mass transfer on the apparent rate constant are discussed.
The explosive reaction of carbon monoxide and oxygen at 973 and 1048 K
Authors: Ahmed S. , Back M. H. 
Published: January 2005

AbstractConditions leading to an explosive reaction of carbon monoxide and oxygen in the presence of small amounts of water have been examined at temperatures of 973 and 1048 K. Carbon monoxide and water were formed in the presence of oxygen by reaction with a thin film of carbon deposited on a quartz vessel. The carbon provided a reactive and reproducible surface, giving aconsistent rate of termination and thus allowing a quantitative descriptionof the conditions at the explosion in the region of the first limit. Calculations of the rates of the various branching and termination reactions at the onset of the explosion showed that the simple mechanism described earlier was still adequate to explain the reaction at temperatures up to 1050 K. From experiments with inert gases the transition from the first explosion limit to the region of the second explosion limit was demonstrated.
The reaction of OH radicals with dimethyl sulfide
Authors: Wallington Timothy J. , Atkinson Roger , Tuazon Ernesto C. , Aschmann Sara M. 
Published: January 2005

AbstractThe kinetics of the gas phase reaction of OH radicals with dimethyl sulfide (CH3SCH3) have been studied at various temperatures and total pressures using two relative rate methods and a flash photolysis technique. For the relative rate methods, rate constants were measured at 296 ± 2 K as a function of the O2 pressure at a total pressure of ca. 740 torr. Data from these three experimental techniques were not in agreement. It is concluded that the relative rate techniques are subject to secondary reactions, possibly involving CH3S radicals. A rate constant of (2.5) × 10−12 e(130 = 102)/T cm3 molecule−1 s−1 obtained using the flash photolysis‐resonance fluorescence data in the absence of O2, and which is in agreement with the lower range of values previously reported in the literature, is recommended.
Kinetic studies on the oxidation of ascorbic acid by technetium(VII)
Authors: Grases F. , Genestar C. , Amat E. 
Published: January 2005

AbstractThe pertechnetate ion oxidizes ascorbic acid in strong acid medium to form red species. A reaction mechanism has been developed which correctly predicts all the experimental facts. The results obtained support the postulate according to which the red species corresponds to a complex formed between Tc(V) and dehydroascorbic acid. The rate constants and Arrhenius parameters have been investigated.
Young‐measure solutions to a generalized Benjamin–Bona–Mahony equation
Authors: Giannoulis Johannes 
Published: January 2005

AbstractWe consider the evolution of microstructure under the dynamics of the generalized Benjamin–Bona–Mahony equation
equation image
with u: ℝ2 → ℝ. If we model the initial microstructure by a sequence of spatially faster and faster oscillating classical initial data vn, we obtain a sequence of spatially highly oscillatory classical solutions un. By considering the Young measures (YMs) ν and µ generated by the sequences vn and un, respectively, as n → ∞, we derive a macroscopic evolution equation for the YM solution µ, and show exemplarily how such a measure‐valued equation can be exploited in order to obtain classical evolution equations for effective (macroscopic) quantities of the microstructure for suitable initial data vn and non‐linearities f. Copyright © 2005 John Wiley & Sons, Ltd.
Scattering theory for the Wigner equation
Authors: Emamirad Hassan , Rogeon Philippe 
Published: January 2005

AbstractWe prove that the Wigner equation is well‐posed in Lp(ℝ2n) for some potential V. From the formalism established by Markovich, we show the completeness of wave operators for the Wigner equation in L2. Using estimations proved by Castella and Perthame, on the one hand, and the Lp→Lq estimations for the Schrödinger group, on the other hand, we prove the existence of the wave operators in L2,p spaces. Copyright © 2005 John Wiley & Sons, Ltd.
Nitric oxide levels and ciliary beat frequency in indigenous New Zealand children
Authors: Edwards E.A. , Douglas C. , Broome S. , Kolbe J. , Jensen C.G. , Dewar A. , Bush A. , Byrnes C.A. 
Published: January 2005

AbstractNew Zealand children's morbidity from respiratory disease is high. This study examines whether subclinical ciliary abnormalities underlie the increased prevalence of respiratory disease in indigenous New Zealand children. A prospective study enrolled a group of healthy children who were screened for respiratory disease by questionnaire and lung function. Skin‐prick tests were performed to control for atopy. Exhaled and nasal NO was measured online by a single‐breath technique using chemiluminescence. Ciliary specimens were obtained by nasal brushings for assessment of structure and function. The ciliary beat frequency (CBF) (median CBF, 12.5 Hz; range, 10.4–16.8 Hz) and NO values (median exhaled NO, 5.6 ppb; range, 2.3–87.7 ppb; median nasal NO, 403 ppb; range, 34–1,120 ppb) for healthy New Zealand European (n = 58), Pacific Island (n = 61), and Maori (n = 16) children were comparable with levels reported internationally. No ethnic differences in NO, atopy, or CBF were demonstrated. Despite an apparently normal ciliary beat, the percentage of ciliary structural defects was 3 times higher than reported controls (9%; range, 3.6–31.3%), with no difference across ethnic groups. In conclusion, it is unlikely that subclinical ciliary abnormalities underlie the increased prevalence of respiratory disease in indigenous New Zealand children. The high percentage of secondary ciliary defects suggests ongoing environmental or infective damage. Pediatr Pulmonol. 2005; 39:238–246. © 2005 Wiley‐Liss, Inc.
Subglottic hemangioma: A comparison of CO2 laser, Neodym‐Yag laser, and tracheostomy
Authors: Nicolai Thomas , Fischer‐Truestedt Cordula , Reiter Karl , Grantzow Rainer 
Published: January 2005

AbstractFor airway obstruction caused by subglottic hemangiomas, tracheostomy is still regarded by some as the only established therapy, despite numerous other therapeutic options. Resection with lasers was also reported, but subglottic scar formation may occur, and different laser types may have advantages over others. The charts of 46 consecutive patients over 26 years were reviewed. Until 1986, therapy involved systemic steroids or tracheostomy. Thereafter, a Neodym‐Yag and after 1995 a CO2 laser was used. Mean initial stenosis was 61.0% in the first (n = 15), 85.8% in the Neodym‐Yag (n = 14), and 86.7% in the CO2 period (n = 17). Tracheostomy rates could be reduced from 76.9% to 46.9% with the Neodym‐Yag and to 30.8% with the CO2 laser, and to 22.2% in children not intubated before referral. One tracheostomy obstruction resulted in severe neurological damage; granulomas required resection in 37.5%. Secondary subglottic stenosis was found in 15.4% with the Neodym‐Yag, but not with the CO2 laser. With tracheostomy, 12.5% were symptom‐free at age 2–3 years, vs. 25.0% in the Neodym‐Yag and 41.6% in the CO2 laser period. Speech development was delayed in 75.0% with tracheostomy, and parental anxiety lessened in only 18.8% before the second birthday (68.8% without tracheostomy). Since the end of the retrospective analysis, we treated a further 21 patients (mean stenosis, 83.3%) with the CO2 laser, with only one tracheostomy (4.8%). Compared to steroids and tracheostomy, a significant reduction in morbidity and speech developmental delay, and an improved quality of life, were achieved with CO2 laser resection, and this approach was superior to the Neodym‐Yag laser. Pediatr Pulmonol. 2005; 39:233–237. © 2005 Wiley‐Liss, Inc.
Induced sputum matrix metalloproteinase‐9 correlates with lung function and airway inflammation in children with cystic fibrosis
Authors: Sagel Scott D. , Kapsner Robert K. , Osberg Iris 
Published: January 2005

AbstractMatrix metalloproteinases (MMPs) degrade extracellular matrix and are implicated in causing airway damage in chronic inflammatory lung diseases, including cystic fibrosis (CF). Our primary objective was to examine the relationship between matrix metalloproteinase‐9 (MMP‐9) and pulmonary function, as measured by forced expiratory volume in 1 sec (FEV1), in children with CF. We measured MMP‐9 and its natural tissue inhibitor of metalloproteinase‐1 (TIMP‐1) in induced sputum from 18 clinically stable CF children with normal to mildly abnormal lung function and 7 healthy control children. Measures of airway inflammation from induced sputum included cell counts and differentials, interleukin‐8 (IL‐8), neutrophil elastase, MMP‐9, and TIMP‐1. Infection was assessed through quantitative bacterial counts. Induced sputum levels of MMP‐9 and TIMP‐1 were significantly increased in children with CF compared with healthy controls. Also, the MMP‐9/TIMP‐1 molar ratio was higher in the CF group. Among CF children, there was a significant inverse relationship between MMP‐9 and FEV1. In addition, sputum MMP‐9 and TIMP‐1 concentrations significantly correlated with total white cells and neutrophils, IL‐8, and neutrophil elastase. Neither MMP‐9 nor TIMP‐1 correlated with airway infection. We conclude that clinically stable CF children with normal to mildly abnormal lung function have an increased burden of MMP‐9 in their airways. The observed relationships of MMP‐9 with lung function and other measures of airway inflammation suggest that this enzyme may be a useful marker of airway injury and airflow obstruction in persons with CF. Pediatr Pulmonol. 2005; 39:224–232. © 2005 Wiley‐Liss, Inc.
Verbindung von gelöstem Stoff und Lösungsmittel aus Verteilungskoeffizienten
Authors: Dhar N. R. 
Published: January 2005

Abstract1. Die Versuchsergebnisse zeigen, daß die Verteilungskoeffizienten von Stoffen wie Lithiumchlorid, Silberperchlorat, Dimethylammoniumchlorid, Citronensäure, Weinsäure usw. viel größer sind, als das Verhältnis ihrer Löslichkeiten in Wasser und dem nichtwäßrigen Lösungsmittel.Ähnliche Ergebnisse sind erhalten worden mit Koffein, Strychnin und Atropin zwischen Wasser und Chloroform.
Über die durch Einwirkung von Sauerstoff auf feste Metallchloride (CuCl2, NiCl2, CoCl2) entstehenden Gleichgewichte. (2 MeCl2 + O2 ⇌ 2 MeO + 2 Cl2)
Authors: Jellinek K. , Rudat A. 
Published: January 2005

AbstractEs wurden Gleichgewichte vom Typus

bei festem CuCl2, NiCl2 und CoCl2, zwischen 300 und 600° C untersucht. Bei CuCl2, verläuft die Reaktion zunächst über CuOCuCl2, welches erst dann in CuO übergeht, bei NiCl2 tritt eine Verwandlung in NiO, bei CoC12, in Co3O4 auf. Die aus den Gleichgewichten errechneten Wärmetönungen stimmen genügend gut mit den thermochemisch beobachteten überein. Die Gleichgewichte verdienen insofern auch technisches Interesse, als man umgekehrt wie oben aus den natürlichen Oxyden durch chlorierendes Rösten die leicht in Wasser löslichen Chloride der erwähnten Metalle, insbesondere CuCl2, gewinnen kann und die maximalen Ausbeuten, bis zu denen dies möglich ist, auf das aufgewendete Chlor berechnet, aus den Gleichgewichten zu entnehmen sind.
Über eine Natürliche Reihe der Stoffe nach ihren Kohäsionskräften
Authors: Kirejew Valentin 
Published: January 2005

AbstractDie Untersuchung der experimentellen Daten der Funktion \documentclass{article}\pagestyle{empty}\begin{document}$ p\frac{{d\,T}}{{p\,d}} $\end{document} führt uns zu der Aufeinanderfolge der Stoffe nach der Größe ihrer Kohäsionskräfte, wobei es sich erweist, daß erstens im koexistierenden Dampfflüssigkeitszustande die Aufeinanderfolge der Stoffe Temperaturwechsel sich fast nicht ändert, und zweitens, daß mit dieser Reihe die verschiedenen Größen, welchen gewöhnlich eine konstante Bedeutung für verschiedene Stoffe zugeschrieben wird (z. B. der TROUTON'sche Koeffizient, der kritische Koeffizient \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{{R \cdot \,T_k \cdot d_k }}{{M \cdot p_k }} $\end{document}, der Brechungsindex im kritischen Punkte, das Gesetz der korrespondierenden Zustände und andere), eng verbunden sind.
Zur elektrolytischen Dissoziation der zweibasischen Säuren. III. Bestimmung zweiter Dissoziationskonstanten aus Löslichkeitsversuchen
Authors: Larsson Erik 
Published: January 2005

AbstractEs wird eine Methode beschrieben, zweite Dissoziationskonstanten zweibasischer Säuren aus der Löslichkeit einer schwerlöslichen einbasischen Säure in der Lösung eines neutralen Salzes der zweibasischen Säure zu berechnen. Die Anwendbarkeit der Methode wird an Oxalsäure, Bernsteinsäure, Fumarsäure, l‐Apfelsäure und d‐Weinsäure geprüft.