摘要:

AbstractAs part of an ongoing program to model hydrocarbon assisted boron combustion, a kinetic model has been developed to describe gasification of the ubiquitous boron oxide coating that inhibits particulate boron ignition. This model includes homogeneous gas phase oxidation reactions, multi‐component gas phase diffusion, heterogeneous surface reactions, and oxide vaporization. The kinetic processes are treated using a generalized kinetics code, with embeded sensitivity analysis, for the combustion of a one‐dimensional (particle radius), spherical particle.This article presents the heterogeneous surface reactions used to describe oxide gasification and presents selected model results for a spherical boron oxide droplet which illustrate the dependence of the oxide gasification rates on the ambient temperature and particle diame

ISSN:0538-8066    

DOI:10.1002/kin.550231102

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractDecomposition of hydrogen peroxide in high‐purity water has been measured at temperatures ranging 100 to 280°C in a laboratory test loop. A first‐order decomposition kinetics has been observed in all cases, but the decomposition rates were found to vary widely, depending on the material used in the reaction chamber. In a 4 mm ID stainless steel tubing, the decomposition rate constant is determined to bek= 2 × 105exp(−14800/RT). This decomposition rate is approximately 100 times faster than that observed in a Teflon tubing.The variation of decomposition rate in different reaction chambers is attributed to the heterogeneous catalytic effects. There is no evidence of reaction between H2and H2O2in the highpurity water at temperatures up t

ISSN:0538-8066    

DOI:10.1002/kin.550231103

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractRate of oxidation of acetophenones by Ce(IV) in aqueous acetic acid 80:20 (v/v) either slows down or remains constant over a range of cetyltrimethyl ammonium bromide (CTAB) concentration exceeding the cmc value. The rate is then found to increase sharply as the surfactant concentration increases with no sign of reaching a maximum or constant value. From Fluorescence quenching, binding constant forp‐nitro acetophenone has been evaluated. The rate data have been rationalized on the basis of a reaction between the acetophenones situated on the micelle surface and active Ce(IV) species in the bulk aqueous phas

ISSN:0538-8066    

DOI:10.1002/kin.550231104

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe products of the reaction of the hydroxyl (OH) radical with methyltert‐butyl ether (MTBE) in NOx‐air systems were identified and measured by Fourier transform infrared absorption spectroscopy and gas chromatography. The products observed, and their yields, were as follows:t‐butyl formate, 76 ± 7%; formaldehyde, 37 −1+6%; methyl acetate, 17 ± 2%, and acetone, 2.1 ± 0.9%, where the stated error limits represent both random (two standard deviations) and estimated systematic uncertainties. These products account for ca. 95% of the MTBE carbon reacted. Infrared absorption bands which may be due to small amounts of organic nitrate formation were observed, but organic nitrate yields could not be quantified. These data allow a chemical mechanism for the reaction of MTBE with the OH radical in the presence of NOxto b

ISSN:0538-8066    

DOI:10.1002/kin.550231105

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe reaction of CH3with OH has been studied near 1200 K and 1 atmosphere pressure in shock tube experiments in which UV absorption was used to monitor [OH]. A rate coefficient of (1.1 ± 0.3) × 1013cm3/mol‐s was measured for removal of OH by CH3. This measured value is compared with previous experimental data and calculations. Several possible reaction channels are discussed, and although products were not monitored, it seems probable, on the basis of other work and theoretical estimates, that the primary mechanism (≃75%) for the removal of OH by CH3at these conditions is their combination to form CH3OH. Rate coefficients of (5.3 ± 0.8) × 1012and (9.0 ± 1.4) × 1012cm3/mol‐s were measured for the reactions of OH with acetone and ethane, respectively, at the same temperature a

ISSN:0538-8066    

DOI:10.1002/kin.550231106

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe rate coefficients of the reactionsandwere determined in a series of shock tube experiments from CN time histories recorded using a narrow‐linewidth cw laser absorption technique. The ring dye laser source generated 388.44 nm radiation corresponding to the CN B2Σ+(v= 0) ←X2Σ+(v= 0) P‐branch bandhead, enabling 0.1 ppm detection sensitivity.Reaction (1) was measured in shock‐heated gas mixtures of typically 200 ppm N2O and 10 ppm C2N2in argon in the temperature range 3000 to 4500 K and at pressures between 0.45 and 0.90 atm.k1was determined using pseudo‐first order kinetics and was found to be 7.7 × 1013(±20%) [cm3mol−1s−1]. This value is significantly higher than reported by earlier workers. Reaction (2) was measured in two regimes. In the first, nominal gas mixtures of 500 ppm O2and 10 ppm C2N2in argon were shock heated in the temperature range 2700 K to 3800 K and at pressures between 0.62 and 1.05 atm.k2was determined by fitting the measured CN profiles with a detailed mechanism. In the second regime, gas mixtures of 500 ppm O2and 1000 ppm C2N2in argon were shock heated in the temperature range 1550 to 1950 K and at pressures between 1.19 and 1.57 atm. Using pulsed radiation from an ArF excimer laser at 193 nm, a fraction of the C2N2was photolyzed to produce CN. Pseudo‐first order kinetics were used to determinek2. Combining the results from both regimes,k2was found to be 1.0 × 1013

ISSN:0538-8066    

DOI:10.1002/kin.550231107

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550231101

出版商:John Wiley&Sons, Inc.    

年代:1991

数据来源: WILEY