513. The kinetics of the photolysis of acetaldehyde. Part II. The rate of production of methyl radicals

Author(s):  
A. S. Buchanan
Keyword(s):  
1981 ◽  
Vol 83 (2) ◽  
pp. 409-412 ◽  
Author(s):  
Fumiaki Yamada ◽  
Irene R. Slagle ◽  
D. Gutman

1964 ◽  
Vol 17 (12) ◽  
pp. 1329 ◽  
Author(s):  
MFR Mulcahy ◽  
DJ Williams ◽  
JR Wilmshurst

The kinetics of abstraction of hydrogen atoms from the methyl group of the toluene molecule by methyl radicals at 430-540�K have been determined. The methyl radicals were produced by pyrolysis of di-t-butyl peroxide in a stirred-flow system. The kinetics ,agree substantially with those obtained by previous authors using photolytic methods for generating the methyl radicals. At toluene and methyl-radical concentrations of about 5 x 10-7 and 10-11 mole cm-3 respectively the benzyl radicals resulting from the abstraction disappear almost entirely by combination with methyl radicals at the methylenic position. In this respect the benzyl radical behaves differently from the iso-electronic phenoxy radical, which previous work has shown to combine with a methyl radical mainly at ring positions. The investigation illustrates the application of stirred-flow technique to the study of the kinetics of free-radical reactions.


1993 ◽  
Vol 312 ◽  
Author(s):  
Robert S. Windeler ◽  
Robert F. Hicks

AbstractA mathematical model has been developed of the reactor used by Larsen et al. [1] to study the kinetics of gallium arsenide MOCVD.- Two different surface reactions were considered as the rate-limiting step in film growth below 500°C: (1) the desorption of methyl radicals from adsorbed trimethylgallium, and (2) the reaction of CH3 and H groups from adsorbed trimethylgallium and arsine to make methane. The latter step is consistent with the experimental results. It explains the rapid acceleration of the precursor decomposition rates when they are fed together to the reactor. It also explains why methane is the only hydrocarbon generated from trimethylgallium and arsine decomposition in deuterium at V/Ill ratios greater than 1.0.


1995 ◽  
Vol 240 (1-3) ◽  
pp. 63-71 ◽  
Author(s):  
Jerzy T. Jodkowski ◽  
Emil Ratajczak ◽  
Kjell Fagerström ◽  
Anders Lund ◽  
Nigel D. Stothard ◽  
...  

1965 ◽  
Vol 18 (1) ◽  
pp. 20 ◽  
Author(s):  
MFR Mulcahy ◽  
DJ Williams

Knowledge of the reactivity of phenols towards simple free radicals is needed to throw light on the behaviour of the phenolic substances involved in the pyrolysis of coal and other organic materials. In the present investigation the reaction between methyl radicals and phenol vapour has been studied a t total pressures from 0.5 to 3 cmHg and temperatures from 445 to 547°K, the concentrations of methyl radicals and phenol being varied from 2 × 10-12 to 4 × 10-11 and 1 × 10-8 to 8 × 10-7 mole cm-3 respectively. The main products identified by gas chromatography were methane and o- and p-cresol, together with a little anisole and 2,4- and 2,6-dimethylphenol. The cresols are produced via hydrogen abstraction Diagram followed by combination of a methyl radical at a ring position of the phenoxy radical either ortho or para to the oxygen atom, e.g. in the case of the para position: Diagram The kinetics can be explained by postulating (a) that the keto forms of the cresols (methylcyclohexadienones) formed initially by reaction (6) have a finite lifetime in the gaseous phase and (b) that these molecules, which contain a tertiary hydrogen atom α to a system of a carbonyl bond and two carbon-carbon double bonds, partly undergo hydrogen abstraction by methyl radicals before they are able to enolize: CH3· + (HCH3 = C6H4 = O → CH4 + CH3C6H4O· The mechanism is consistent with the kinetics of formation of methane, the distribu- tion of the free electron in the phenoxy radical, the formation of o- and p-cresols as major products, the kinetics of formation of the cresols, and the high reactivity of the intermediate product towards methyl radicals.


Author(s):  
Nguyen Huu Tho ◽  
Nguyen Vo Hieu Liem ◽  
Nguyen Thi Huynh Nhu ◽  
Nguyen Thi Hong ◽  
Ngo Vo Thanh ◽  
...  

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.


1975 ◽  
Vol 6 (13) ◽  
Author(s):  
MARJA-LIISA POHJONEN ◽  
LEILA LEINONEN ◽  
HELGE LEMMETYINEN ◽  
JOUKO KOSKIKALLIO

Sign in / Sign up

Export Citation Format

Share Document