摘要:

AbstractInvestigation of the photochromic system TPID/CHCl3(TPID = triphenylimidazolyl dimer) in a CSTR provided the first example of isothermal photochemical bistability. The reaction mechanism was established and the relevant kinetic and spectroscopic parameters were estimated experimentally. In order to predict the quantitative dynamic behavior of the TPID/CHCl3system these parameters were refined numerically using batch reactor data.The adjusted model simulates very accurately bistability either as a function of residence time τ, or as a function of incident photon flux I0

ISSN:0538-8066    

DOI:10.1002/kin.550240402

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractExperimental profiles of stable species concentrations and temperature are reported for the flow reactor oxidation of ethanol at atmospheric pressure, initial temperatures near 1100 K and equivalence ratios of 0.61–1.24. Acetaldehyde, ethene, and methane appear in roughly equal concentrations as major intermediate species under these conditions. A detailed chemical mechanism is validated by comparison with the experimental species profiles. The importance of including all three isomeric forms of the C2H5O radical in such a mechanism is demonstrated. The primary source of ethene in ethanol oxidation is verified to be the decomposition of the C2H4OH radical. The agreement between the model and experiment at 1100 K is optimized when the branching ratio of the reactions of C2H5OH with OH and H is defined by (30% C2H4OH + 50% CH3CHOH + 20% CH3CH2O) + XH. As in methanol oxidation, HO2chemistry is very important, while the H + O2chain branching reaction plays only a minor role until late in fuel decay, even at temperatures above 1100

ISSN:0538-8066    

DOI:10.1002/kin.550240403

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe kinetics of the gas‐phase reactions of 1,4‐benzodioxan, 2,3‐dihydrobenzofuran, and 2,3‐benzofuran with OH radicals and O3have been studied at 298 ± 2 K and atmospheric pressure of air and the products have also been investigated. 1,4‐Benzodioxan and 2,3‐dihydrobenzofuran were chosen as volatile model compounds for dibenzo‐p‐dioxin and dibenzofuran, respectively. The rate constants, or upper limits thereof, for the O3reactions were (in cm3molecule−1s−1units): 1,4‐benzodioxan,<1.2 × 10−20; 2,3‐dihydrobenzofuran,<1 × 10−19; and 2,3‐benzofuran, (1.83 ± 0.21) × 10−18. Using a relative rate method, the rate constants for the OH radical reactions (in cm3molecule−1s−1units) were: 1,4‐dibenzodioxan, (2.52 ± 0.38) × 10−11; 2,3‐dihydrobenzofuran, (3.66 ± 0.56) × 10−11; and 2,3‐benzofuran, (3.73 ± 0.74) × 10−11. Salicylaldehyde was observed as a product of the OH radical‐initiated and O3reactions of 2,3‐benzofuran, with measured

ISSN:0538-8066    

DOI:10.1002/kin.550240404

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe kinetics and mechanism of the reaction of Ni(II) with heptane‐,5‐dione (Hhptd) have been investigated in concentrated sodium perchlorate aqueous solutions at 298 K. The kinetic data in the different media are consistent with a mechanism in which Ni(II) reacts with the enol form of the ligand. The observed positive salt effect on the rate of the reaction of formation of the complex Nihptd+is rationalized taking into account the increase of the rate of water exchange from the first solvation sphere of the metal ion to the bulk solvent when increasing salt concentrat

ISSN:0538-8066    

DOI:10.1002/kin.550240405

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe reaction mechanism of the halogen (Cl and Br)‐atom initiated oxidation of C2H4was studied using the long path FTIR spectroscopic method in 700 torr of air at 296 ± 2 K. Among the major halogen‐containing products were XCH2CHO, XCH2CH2OH, and XCH2CH2OOH (X = Cl or Br) which were shown to be formed via the self‐reaction of the XCH2CH2OO radicals, i.e., 2XCH2CH2OO → 2XCH2CH2O + O2; (a) 2XCH2CH2OO → XCH2CHO + XCH2CH2OH + O2and (b) followed by XCH2CH2O + O2→ XCH2CHO + HO2and XCH2CH2OO + HO2→ XCH2CH2OOH + O2. From the observed yields of XCH2CHO and XCH2CH2OH the branching ratios for reactions (a) and (b) were determined to beka/kb= 1.35 ± 0.07(2σ) for both X = Cl and Br. In addition, the O2‐dependence of the rate constant for the Br + C2H4reaction was determined by the relative rate technique as a function of O2partial pressure from 140 to 700 torr at 700 torr total pressure of N2/O2diluent. Rate constants for the reactions of Cl‐atoms with Cl‐CH2CHO and Br‐atoms with Br‐CH2CHO were also determined to be [4.3 ± 0.2(2sigma;)] × 10−11and less than or equa

ISSN:0538-8066    

DOI:10.1002/kin.550240406

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

摘要:

AbstractThe oxidation ofn‐heptane has been studied in a jet‐stirred flow reactor in the temperature range 950–1200 K at atmospheric pressure for a wide range of fuel‐oxygen equivalence ratios (0.2 to 2.0). A chemical kinetic reaction mechanism developed from previous studies on smaller hydrocarbons and extended to C6and C7species was used to reproduce the experimental data. Good agreement between computed and measured concentrations of major chemical species was obtained for the entire range of experimental conditions. Sensitivity analyses were carried out to identify the reactions having the greatest influence on the modeling results. The major reaction paths forn‐heptane consumption and for the formation of the main products have been identified.In additionn‐heptane ignition delays behind a reflected shock wave measured by other investigators were used to validate the present reaction mechanism at higher temperature a

ISSN:0538-8066    

DOI:10.1002/kin.550240407

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY

ISSN:0538-8066    

DOI:10.1002/kin.550240401

出版商:John Wiley&Sons, Inc.    

年代:1992

数据来源: WILEY