TY - JOUR
T1 - A computational study on the kinetics and mechanism for the unimolecular decomposition of o-nitrotoluene
AU - Chen, S. C.
AU - Xu, S. C.
AU - Diau, Wei-Guang
AU - Lin, Ming-Chang
PY - 2006/8/24
Y1 - 2006/8/24
N2 - The kinetics and mechanism for the unimolecular decomposition of o-nitrotoluene (o-CH 3C 6H 4NO 2) have been studied computationally at the G2M(RCC, MP2)//B3LYP/6-311G(d, p) level of theory in conjunction with rate constant predictions with RRKM and TST calculations. The results of the calculations reveal 10 decomposition channels for o-nitrotoluene and its six isomeric intermediates, among them four channels give major products: CH 3C 6H 4 + NO 2, C 6H 4C(H)ON (anthranil) + H 2O, CH 3C 6H 4O (o-methyl phenoxy) + NO, and C 6H 4C(H 2)NO + OH. The predicted rate constants in the 500-2000 K temperature range indicate that anthranil production, taking place initially by intramolecular H-abstraction from the CH 3 group by NO 2 followed by five-membered ring formation and dehydration, dominates at temperatures below 1000 K, whereas NO 2 elimination becomes predominant above 1100 K and CH 3C 6H 4O formation by the nitro-nitrite isomerization/decomposition process accounts for only 5-11% of the total product yield in the middle temperature range 800-1300 K. The branching ratio for CH 2C 6H 4NO formation by the decomposition process of CH 2C 6H 4N-(O)OH is negligible. The predicted high-pressure-limit rate constants with the rate expression of 4.10 × 10 17 exp[-37000/T] s -1 for the NO 2 elimination channel and 9.09 × 10 12 exp[-25800/T] s -1 for the H 2O elimination channel generally agree reasonably with available experimental data. The predicted high-pressure-limit rate constants for the NO and OH elimination channels are represented as 1.49 × 10 14 exp[-30000/T] and 1.31 × 10 15 exp[-38000/T] s -1, respectively.
AB - The kinetics and mechanism for the unimolecular decomposition of o-nitrotoluene (o-CH 3C 6H 4NO 2) have been studied computationally at the G2M(RCC, MP2)//B3LYP/6-311G(d, p) level of theory in conjunction with rate constant predictions with RRKM and TST calculations. The results of the calculations reveal 10 decomposition channels for o-nitrotoluene and its six isomeric intermediates, among them four channels give major products: CH 3C 6H 4 + NO 2, C 6H 4C(H)ON (anthranil) + H 2O, CH 3C 6H 4O (o-methyl phenoxy) + NO, and C 6H 4C(H 2)NO + OH. The predicted rate constants in the 500-2000 K temperature range indicate that anthranil production, taking place initially by intramolecular H-abstraction from the CH 3 group by NO 2 followed by five-membered ring formation and dehydration, dominates at temperatures below 1000 K, whereas NO 2 elimination becomes predominant above 1100 K and CH 3C 6H 4O formation by the nitro-nitrite isomerization/decomposition process accounts for only 5-11% of the total product yield in the middle temperature range 800-1300 K. The branching ratio for CH 2C 6H 4NO formation by the decomposition process of CH 2C 6H 4N-(O)OH is negligible. The predicted high-pressure-limit rate constants with the rate expression of 4.10 × 10 17 exp[-37000/T] s -1 for the NO 2 elimination channel and 9.09 × 10 12 exp[-25800/T] s -1 for the H 2O elimination channel generally agree reasonably with available experimental data. The predicted high-pressure-limit rate constants for the NO and OH elimination channels are represented as 1.49 × 10 14 exp[-30000/T] and 1.31 × 10 15 exp[-38000/T] s -1, respectively.
UR - http://www.scopus.com/inward/record.url?scp=33748552334&partnerID=8YFLogxK
U2 - 10.1021/jp0623591
DO - 10.1021/jp0623591
M3 - Article
C2 - 16913688
AN - SCOPUS:33748552334
SN - 1089-5639
VL - 110
SP - 10130
EP - 10134
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 33
ER -