Laboratory measurements of gas‐phase reactions of polyatomic carbon ions C+n(n=1–6) and CnH+(n=2–5) with carbon monoxide

1987 ◽  
Vol 87 (12) ◽  
pp. 6934-6938 ◽  
Author(s):  
Diethard K. Bohme ◽  
Stanisl/aw Wl/odek ◽  
Leslie Williams ◽  
Leonard Forte ◽  
Arnold Fox
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Carbon Ions ◽  
Laboratory Measurements ◽  
Gas Phase Reactions

The Gas Phase Reactions of Recoil Sulfur Atoms with Carbon Monoxide and Carbon Dioxide1

1964 ◽  
Vol 68 (2) ◽  
pp. 318-322 ◽  
Author(s):  
Edward K. C. Lee ◽  
Y. N. Tang ◽  
F. S. Rowland
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Gas Phase Reactions

Gas-Phase Reactions between Diborane and Carbon Monoxide:  A Theoretical Study

2003 ◽  
Vol 107 (46) ◽  
pp. 9974-9983 ◽  
Author(s):  
Shao-Wen Hu ◽  
Yi Wang ◽  
Xiang-Yun Wang ◽  
Ti-Wei Chu ◽  
Xin-Qi Liu
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Theoretical Study ◽  
Gas Phase Reactions

Fire Plume Along Vertical Surfaces: Effect of Finite-Rate Chemical Reactions

1984 ◽  
Vol 106 (4) ◽  
pp. 713-720 ◽  
Author(s):  
C. H. Chen ◽  
J. S. T’ien
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Chemical Reactions ◽  
Vertical Wall ◽  
Fire Plume ◽  
Gas Phase Reactions ◽  
Finite Rate ◽  
Slowing Down ◽  
Kinetic Rates ◽  
Relative Kinetic

Fire plume along a vertical wall is analyzed using a laminar boundary layer model, including finite-rate, gas-phase chemical kinetics. The chemical reactions include two semiglobal steps: In the first, fuel is oxidized to form carbon monoxide and water vapor, and in the second, carbon monoxide is oxidized to form carbon dioxide. Several important nondimensional kinetic parameters are identified and a parametric study is given. The computed results indicate that by slowing down the relative kinetic rates in the gas-phase reactions, the total surface heat transfer rate and the preheating distance are decreased. Furthermore, slowing down the kinetics also increases the amount of unreacted combustibles that escape from the flame.

Methylene II. Gas phase reactions with ethyl chloride

1968 ◽  
Vol 306 (1485) ◽  
pp. 135-158 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Energy Content ◽  
Incident Light ◽  
Hydrogen Abstraction ◽  
Relative Concentration ◽  
Radical Mechanism ◽  
Gas Phase Reactions ◽  
Free Radical Mechanism ◽  
Singlet Methylene

In this work methylene was prepared by the photolysis of ketene, and the experiments include observations of the effects of changing the wavelength of the photolysing light and of introducing foreign gases. Results are consistent with a free-radical mechanism in which CH 2 abstracts a chlorine or a hydrogen atom from C 2 H 5 Cl: CH 2 +CH 3 CH 2 Cl→ k cl ĊH 2 Cl+CH 3 ĊH 2 , CH 2 +CH 3 CH 2 Cl→ k h1 ĊH 3 +ĊH 3 CH 3 Cl, } CH 2 +CH 3 CH 2 Cl→ k H2 ĊH 3 +CH 3 ċHCl. } ( k H ) All the fourteen products of the radical recombinations have been identified. Disproportionation of radicals and decomposition of excited molecules formed by recombinations yield additional products. Methylene insertion does not appear to play a significant role. When the incident light contains wavelengths in the region 2450 to 4000Å we find that k Cl / k H =1·62, k H1 / k H2 =0·098. If shorter wavelengths are excluded, or if nitrogen is added, lower values of k Cl / k H are obtained. On the other hand, in the presence of carbon monoxide the value of k Cl / k H may be greatly increased. It is suggested that these findings are attributable to differences in reactivity between singlet and triplet methylene. At longer wavelengths, or when nitrogen is present, the relative concentration of the singlet is reduced, but in the presence of carbon monoxide the triplet is removed preferentially (De Graff & Kistiakowsky 1967). Singlet methylene appears to be highly discriminating in its reactions, abstracting chlorine preferentially, while the triplet discriminates in favour of hydrogen abstraction. A kinetic analysis based on these ideas and consistent with the experimental observations shows that k S Cl / k S H >16·3, k T Cl / k T H <0·14. The selectivities shown by the two species of methylene are thought to be a result of differences in electronic structure rather than energy content.

Mathematical Modeling of Heat and Mass Transfer Processes During Pyrolysis and Combustion of a Single Biomass Particle

2012 ◽  
Author(s):  
Y. Haseli ◽  
J. A. van Oijen ◽  
L. P. H. de Goey
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Carbon Monoxide ◽  
Water Vapor ◽  
Gas Phase ◽  
Combustion Process ◽  
Combustion Model ◽  
Gas Phase Reactions ◽  
Transfer Processes ◽  
Mass Transfer Processes

A detailed mathematical model is developed for simulation of heat and mass transfer processes during the pyrolysis and combustion of a single biomass particle. The kinetic scheme of Shafizadeh and Chin is employed to describe the pyrolysis process. The light gases formed during the biomass pyrolysis is assumed to consist of methane, carbon dioxide, carbon monoxide, hydrogen and water vapor with given mass fractions relevant to those found in the experiments of high heating conditions. The combustion model takes into account the reactions of oxygen with methane, hydrogen, carbon monoxide, tar and char as well as gasification of char with water vapor and carbon dioxide. Appropriate correlations taken from past studies are used for computation of the rate of these reactions. The model allows calculation of time and space evolution of various parameters including biomass and char densities, gaseous species and temperature. Different experimental data reported in the literature are employed to validate the pyrolysis and combustion models. The reasonable agreement obtained between the predictions and measured data reveals that the presented model is capable of successfully capturing various experiments of wood particle undergoing a pyrolysis or combustion process. In particular, the role of gas phase reactions within and adjacent to particle on the combustion process is examined. The results indicate that for the case of small particles in the order of millimeter size and less, one may neglect any effects of gas phase reactions. However, for larger particles, a combustion model may need to include hydrogen oxidation and even carbon monoxide combustion reactions.

Methylene. IV. Gas phase reactions with 2-chloropropane

1969 ◽  
Vol 312 (1509) ◽  
pp. 163-179 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Reaction Mechanism ◽  
Hydrogen Atom ◽  
Transition State ◽  
Gas Phase ◽  
Chlorine Atom ◽  
Halogen Atom ◽  
Gas Phase Reactions ◽  
Alkyl Radicals ◽  
Singlet Methylene

As in earlier studies in this series, the reaction mechanism has been investigated by identi­fication and estimation of the products formed by the interaction of methylene, prepared by the photolysis of ketene, and the chloroalkane. The reaction was examined over a range of initial pressures, with different wavelengths of photolysing light, and in the presence of oxygen and carbon monoxide. Both insertion and abstraction processes are important, but insertion into C—Cl bonds is negligible under our conditions. Singlet methylene, which is responsible for insertion, is again found to be highly selective in its abstraction reactions, the ratio of the relative rates of abstraction of chlorine and hydrogen exceeding 12. The results are consistent with the mechanism suggested earlier (part II), according to which singlet methylene behaves as an electrophilic reagent, and forms a bond with a chlorine atom involving the vacant p-orbital of CH 2 and a filled p-orbital of Cl. Stereo­chemical considerations suggest that the transition state of this reaction is such that no bond­ing between the C atom of CH 2 and that of C—Cl, and hence no insertion into C—Cl, can occur. We believe that insertion into a C—H bond involves interaction of singlet CH 2 with the electrons of the bond, with a triangular transition state. The effect of a chlorine atom in generally reducing the probability of insertion into neighbouring C—H bonds is thought to be the result of the rapid competing reaction between singlet methylene and the halogen atom. A five-centre transition state in which singlet CH 2 is bonded to Cl through its vacant p-orbital and to a hydrogen atom on C 2 through its filled sp 2 -orbital may be partly respon­sible for chloromethane formation. Triplet methylene has been shown to resemble alkyl radicals in its abstraction reactions.

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