Kinetic modelling of methyl radical reactions with formaldehyde and isobutane. Reinterpretation of existing data obtained by molecular modulation spectrometry

1989 ◽  
Vol 85 (7) ◽  
pp. 801 ◽  
Author(s):  
Tarun K. Choudhury ◽  
William A. Sanders ◽  
M. C. Lin
Keyword(s):  
Kinetic Modelling ◽  
Radical Reactions ◽  
Methyl Radical ◽  
Molecular Modulation ◽  
Existing Data

Individual rate constants of methyl radical reactions in the pyrolysis of dimethyl ether

1977 ◽  
Vol 55 (23) ◽  
pp. 4128-4134 ◽  
Author(s):  
Andrew M. Held ◽  
Kim C. Manthorne ◽  
Philip D. Pacey ◽  
Howard P. Reinholdt
Keyword(s):  
Dimethyl Ether ◽  
Rate Constants ◽  
Flow System ◽  
Average Concentration ◽  
Radical Reactions ◽  
Methyl Radical ◽  
Warm Up ◽  
Secondary Reactions ◽  
Ultraviolet Absorption Spectroscopy ◽  
Individual Rate

Dimethyl ether was pyrolyzed in a flow system at 10 to 80 Torr and 1005 K. The average concentration of CH3 radicals in the reactor was measured by ultraviolet absorption spectroscopy. Product yields were measured by gas chromatography. The system was simulated using a computer program, taking into account the warm-up of the entering gas and the occurrence of secondary reactions. Rate constants were varied to find values consistent with experimental observations. The limiting, high pressure rate constant for the recombination of CH3 was estimated to be 1010.5 ± 0.5ℓ mol−1 s−1. Estimated rate constants for the reactions[Formula: see text]were 107.12 ± 0.2ℓ mol−1 s−1 and 107.5 ± 0.4ℓ mol−1 s−1, respectively.

scholarly journals Theoretical Study of the Formation Methane in the Reaction of Methyl Radical with Propanol-2

2018 ◽  
Vol 34 (3) ◽  
Author(s):  
Nguyen Huu Tho ◽  
Nguyen Vo Hieu Liem ◽  
Nguyen Thi Huynh Nhu ◽  
Nguyen Thi Hong ◽  
Ngo Vo Thanh ◽  
...  
Keyword(s):  
Physical Chemistry ◽  
Density Functional ◽  
Theoretical Study ◽  
Polyatomic Molecules ◽  
Radical Reactions ◽  
Chemical Physics ◽  
Methyl Radicals ◽  
Methyl Radical ◽  
Reaction Paths ◽  
Kinetics Of

The reaction paths of the reaction of methyl radical with propanol-2 (i-C3H7OH) were investigated in detail using density functional theory at B3LYP/6-311++G(3df,2p) level. There were seven reaction pathways which form seven products including CH4 + (CH3)2COH, CH4 + (CH3)2CHO, CH4 + CH3CHOHCH2, CH3OH + CH3CHCH3, C2H6 + CH3CHOH, (CH3)2CH-O-CH3 + H and (CH3)3CH + OH. The results of analysis of the reaction paths and thermokinetic parameters showed that methane could be generated from three different channels. The removed H-atom from secondary carbon atom in the propanol-2 molecule is the most favorable of this reaction system. Keywords Methyl, propanol-2, B3LYP, transition state References [1] I. R. Slagle, D. Sarzyński, and D. Gutman, “Kinetics of the reaction between methyl radicals and oxygen atoms between 294 and 900 K,” Journal of Physical Chemistry, 1987.[2] L. Rutz, H. Bockhorn, and J. W. Bozzelli, “Methyl radical and shift reactions with aliphatic and aromatic hydrocarbons: Thermochemical properties, reaction paths and kinetic parameters,” in ACS Division of Fuel Chemistry, Preprints, 2004.[3] N. H. Tho and N. X. Sang, “Theoretical study of the addition and hydrogen abstraction reactions of methyl radical with formaldehyde and hydroxymethylene,” J. Serb. Chem. Soc.; OnLine First - OLF, 2018.[4] D. Ferro-Costas et al., “The Influence of Multiple Conformations and Paths on Rate Constants and Product Branching Ratios. Thermal Decomposition of 1-Propanol Radicals,” Journal of Physical Chemistry A, p. 4790−4800, 2018.[5] M. T. Holtzapple et al., “Biomass Conversion to Mixed Alcohol Fuels Using the MixAlco Process,” Applied Biochemistry and Biotechnology, 1999.[6] C. R. Shen and J. C. Liao, “Metabolic engineering of Escherichia coli for 1-butanol and 1-propanol production via the keto-acid pathways,” Metabolic Engineering, 2008.[7] A. Frassoldati et al., “An experimental and kinetic modeling study of n-propanol and iso-propanol combustion,” Combustion and Flame, vol. 157, pp. 2–16, 2010.[8] M. Z. Jacobson, “Effects of ethanol (E85) versus gasoline vehicles on cancer and mortality in the United States,” Environmental Science and Technology, 2007.[9] P. Gray and A. A. Herod, “Methyl radical reactions with ethanol and deuterated ethanols,” Transactions of the Faraday Society, 1968.[10] Z. F. Xu, J. Park, and M. C. Lin, “Thermal decomposition of ethanol. III. A computational study of the kinetics and mechanism for the CH3+C2H5OH reaction,” Journal of Chemical Physics, 2004.[11] N. H. Tho and D. T. Quang, “Nghiên cứu lý thuyết đường phản ứng của gốc metyl với etanol,” Vietnam Journal of Chemistry, vol. 56, no. 3, pp. 373–378, Jun. 2018.[12] N. H. Tho and N. X. Sang, “Kinetics of the Reaction of Methyl Radical with Methanol,” VNU Journal of Science: Natural Sciences and Technology; Vol 34 No 1DO - 10.25073/2588-1140/vnunst.4725 , Mar. 2018.[13] T. W. Shannon and A. G. Harrison, “The reaction of methyl radicals with methyl alcohol,” Canadian Journal of Chemistry, vol. 41, pp. 2455–2461, 1963.[14] S. L. Peukert and J. V. Michael, “High-temperature shock tube and modeling studies on the reactions of methanol with d-atoms and CH3-radicals,” Journal of Physical Chemistry A, 2013.[15] P. Gray and A. A. Herod, “Methyl radical reactions with isopropanol and methanol, their ethers and their deuterated derivatives,” Transactions of the Faraday Society, 1968.[16] A. D. Becke, “Density functional thermochemistry. I. The effect of the exchange only gradient correction,” Journal of Chemical Physics, vol. 96, p. 2155, 1992.[17] A. D. Becke, “Density-functional thermochemistry. II. The effect of the Perdew-Wang generalized-gradient correlation correction,” The Journal of Chemical Physics, vol. 97, p. 9173, 1992.[18] A. D. Becke, “Density-functional thermochemistry. III. The role of exact exchange,” The Journal of Chemical Physics, vol. 98, p. 5648, 1993.[19] W. Yang, R. G. Parr, and C. Lee, “Various functionals for the kinetic energy density of an atom or molecule,” Physical Review A, vol. 34 (6), pp. 4586–4590, 1986.[20] W. J. Hehre, L. Radom, P. V. R. Schleyer, and J. A. Pople, Ab Initio Molecular Orbital Theory. 1986.[21] M. P. Andersson and P. Uvdal, “New scale factors for harmonic vibrational frequencies using the B3LYP density functional method with the triple-zeta basis set 6-311+G(d,p).,” The journal of physical chemistry. A, vol. 109, pp. 2937–2941, 2005.[22] Frisch, M. J.; Trucks, G. W.; Schlegel, H.B.; Scuseria, G.E.; Robb, M.A.; Cheeseman, J. R., M. Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A.; Nakatsuji, H.; Caricato, J. L. Li, X.; Hratchian, H. P.; Izmaylov, A. F.; Bloino, J.; Zheng, G.; Sonnenberg, T. Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, and Y. . et al. Honda, “Gaussian 09 Revision C.01, Gaussian Inc. Wallingford CT.,” Gaussian 09 Revision C.01. 2010.[23] G. Herzberg, Electronic Spectra and Electronic Structure of Polyatomic Molecules. 1966.[24] L. M. Sverdlov, M. A. Kovner, and E. P. Krainov, Vibrational spectra of polyatomic molecules. New York; Chichester; Jerusalem; London: Wiley ; Israel Program for Scientific Translations, 1974.[25] E. Hirota, “Anharmonic potential function and equilibrium structure of methane,” Journal of Molecular Spectroscopy, vol. 77, pp. 213–221, 1979.[26] P. Venkateswarlu and W. Gordy, “Methyl alcohol. II. Molecular structure,” The Journal of Chemical Physics, 1955.[27] E. . B. Goos A.; Ruscic, B., “Extended Third Millennium Ideal Gas and Condensed Phase Thermochemical Database for Combustion with Updates from Active Thermochemical Tables,” http://garfield.chem.elte.hu/Burcat/burcat.html August-2018.

Divorce and Reconciliation: Radical Recombination

Reactions ◽  
2011 ◽  
Author(s):  
Peter Atkins
Keyword(s):  
Oxygen Atom ◽  
Unpaired Electron ◽  
Radical Reaction ◽  
Pair Bond ◽  
Radical Reactions ◽  
Jet Engines ◽  
Methyl Radical ◽  
Primitive Type ◽  
The Everyday ◽  
The World

In Reaction 3 you saw that a radical is a species with at least one unpaired electron. An ‘unpaired electron’ is a single electron that is present in the molecule but not playing a role in bonding. The French word celebataire conveys the sense of the electron’s forlorn loneliness very well. However, it is capable of joining forces with another unpaired electron on another radical to form a bond. Two examples of radicals are ·OH (1, a hydroxyl radical), and ·CH3 (2, a methyl radical). The dot denotes the unpaired electron. In most cases, radicals are highly reactive and aggressively attack other species in order to use their unpaired electron to pair with an electron on the second species and so form a bond. The most primitive type of radical reaction is simply the clunking together of two radicals, each donating its unpaired electron to the formation of an electron-pair bond, as in the combination of two ·CH3 radicals to form ethane, CH3–CH3, 3. Some species might have more than one unpaired electron that they can use for biting into other molecules. If they are double-fanged, the most common case after ordinary single-fanged radicals, then the species is known as a ‘biradical’. To continue the partnering analogy: the two electrons cohabit but are platonic in their relationship. A very important example is an oxygen atom, O, which is a biradical. For the purposes of this section I shall write it ·O· with two dots for its two relevant electrons. An O2 molecule is also a sort of biradical, so when I want to emphasize its radical nature I shall denote it ·O–O·. There are a lot of reasons why you should be interested in radical reactions. One is that, as I explained in Reaction 3, they take part in the combustion reactions of the everyday world. Combustion reactions include the reactions that take place inside internal combustion and jet engines and move us around the world. Radical reactions occur wherever there is fire. Because fire is sometimes unintended, if the reactions that contribute to it are understood, then better ways to control and quench it can be devised.

Ab initio mechanistic studies of radical reactions. Addition of methyl radical to acetylene and ethylene

1985 ◽  
Vol 118 (6) ◽  
pp. 573-579 ◽  
Author(s):  
Roger Arnaud ◽  
Vincenzo Barone ◽  
Santiago Olivella ◽  
Albert Sole
Keyword(s):  
Ab Initio ◽  
Radical Reactions ◽  
Mechanistic Studies ◽  
Methyl Radical

Bimolecular QRRK analysis of methyl radical reactions

1987 ◽  
Vol 19 (3) ◽  
pp. 207-228 ◽  
Author(s):  
A. M. Dean ◽  
P. R. Westmoreland
Keyword(s):  
Radical Reactions ◽  
Methyl Radical
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