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Kinetic modeling of the free-radical process during the initiated thermal cracking of normal alkanes with 1-nitropropane as an initiator / Yulei Guan in Industrial & engineering chemistry research, Vol. 50 N° 15 (Août 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9054-9062 Titre : Kinetic modeling of the free-radical process during the initiated thermal cracking of normal alkanes with 1-nitropropane as an initiator Type de document : texte imprimé Auteurs : Yulei Guan, Auteur ; Bolun Yang, Auteur ; Suitao Qi, Auteur Année de publication : 2011 Article en page(s) : pp. 9054-9062 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Modeling  Thermal  cracking  Free  radical  Kinetic  model Résumé : To elucidate the accelerating effect of 1-nitropropane on the thennal cracking of normal alkanes, ab initio and density functional theory calculations were performed to investigate the elementary reactions involved in the initiated thermal cracking of a 1-nitropropane/n-heptane mixture. The kinetic parameters were evaluated on the basis of standard transition state theory (TST) or variational transition state theory (VTST) with Wigner tunneling correction. The activation energy for the C-N bond rupture of 1-nitropropane to produce primary n-propyl and nitro radicals is calculated to be 234-269 kJ/mol, while the bond dissociation energy of the C-C bond within the n-heptane molecule is predicted to be at least 335 kJ/mol. These calculated results demonstrate that the presence of 1-nitropropane makes the free radical formation become relatively easier compared with single n-heptane cracking. Furthermore, compared with the C-H bond cleavage and 1,3-H intramolecular transfer, the unstable n-propyl radical mainly follows the C-C bond cleavage pathway to produce ethylene and secondary CH3 radical. After formation of these free radicals, the H-abstraction of n-heptane with radicals occurs readily with considerably lower activation energy than the radical formation step to initiate the chain reaction. The analysis result indicates that the thermal cracking of n-heptane is accelerated mainly due to the change of the initial step from the C-C bond cleavage of n-heptane to the C-N bond rupture of 1-nitropropane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395852 [article] Kinetic modeling of the free-radical process during the initiated thermal cracking of normal alkanes with 1-nitropropane as an initiator [texte imprimé] / Yulei Guan, Auteur ; Bolun Yang, Auteur ; Suitao Qi, Auteur . - 2011 . - pp. 9054-9062. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 15 (Août 2011) . - pp. 9054-9062 Mots-clés : Modeling  Thermal  cracking  Free  radical  Kinetic  model Résumé : To elucidate the accelerating effect of 1-nitropropane on the thennal cracking of normal alkanes, ab initio and density functional theory calculations were performed to investigate the elementary reactions involved in the initiated thermal cracking of a 1-nitropropane/n-heptane mixture. The kinetic parameters were evaluated on the basis of standard transition state theory (TST) or variational transition state theory (VTST) with Wigner tunneling correction. The activation energy for the C-N bond rupture of 1-nitropropane to produce primary n-propyl and nitro radicals is calculated to be 234-269 kJ/mol, while the bond dissociation energy of the C-C bond within the n-heptane molecule is predicted to be at least 335 kJ/mol. These calculated results demonstrate that the presence of 1-nitropropane makes the free radical formation become relatively easier compared with single n-heptane cracking. Furthermore, compared with the C-H bond cleavage and 1,3-H intramolecular transfer, the unstable n-propyl radical mainly follows the C-C bond cleavage pathway to produce ethylene and secondary CH3 radical. After formation of these free radicals, the H-abstraction of n-heptane with radicals occurs readily with considerably lower activation energy than the radical formation step to initiate the chain reaction. The analysis result indicates that the thermal cracking of n-heptane is accelerated mainly due to the change of the initial step from the C-C bond cleavage of n-heptane to the C-N bond rupture of 1-nitropropane. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24395852