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Title: Experimental and Computational Studies of the Kinetics and Mechanisms for C6H5 Reactions with Acetone -h6 and -d6
Journal: J. Phys. Chem. A
Volume: 107
Page(s): 7755 - 7761
Year: 2003
Reference type: Journal article
Squib: 2003CHO/PAR7755-7761
Reaction:
(CH3)2CO + Phenyl → Benzene + CH3C(O)CH2(·)
Reaction order:
2
Temperature:
298 - 1200
K
Pressure: 2.67E-2 - 1.00E-1 bar
Rate expression:
6.96x10-15 [±2.46x10-15 cm3/molecule s] (T/298 K)(4.20±0.10) e3875 [±216 J/mole]/RT
Bath gas:
Ar
Category: Theory
Data type:
Transition state theory
Comments:
Combined experimental and quantum study. C6H5 produced by 248 nm KrF excimer laser photolysis of C6H5NO. C6H5 detected using cavity ring down spectroscopy at 504.8 nm versus time. Typical acetone 0-0.35 torr in 20-75 torr Argon. Used both acetone and deuterated acetone (d6).
DFT quantum calculations B3LYP/aug-cc-pvTZ energies. Rate expressions calculated using Truhlars Polyrate program. Tunneling correction CVT/SCT employed.
Quantum calculations found abstraction barrier of about 3.9 kcal/mol, C addition channel with barrier of about 9.4 kcal/mol, and O addition channel with barrier of about 12.4 kcal/mol. Thus, abstraction dominates. C addition channel can lead to beta scission of CH3 and formation of methyl phenyl ketone with calculated barrier of about 8.1 kcal/mol
Used transition states from quantum calculations to get functional form of rate expression in order to provide expression over a range of temperatures (298-1200 K). Adjusted calculated barrier of 3.9 kcal/mol to 3.3 kcal/mol to get rate expression to agree with experimental rate constants.
View full bibliographic record.
Rate constant values calculated from the Arrhenius expression:
| T (K) | k(T) [cm3/molecule s] |
|---|---|
| 298 | 3.32E-14 |
| 300 | 3.38E-14 |
| 350 | 5.18E-14 |
| 400 | 7.68E-14 |
| 450 | 1.11E-13 |
| 500 | 1.55E-13 |
| 550 | 2.13E-13 |
| 600 | 2.86E-13 |
| 650 | 3.77E-13 |
| 700 | 4.89E-13 |
| 750 | 6.25E-13 |
| 800 | 7.88E-13 |
| 850 | 9.83E-13 |
| 900 | 1.21E-12 |
| 950 | 1.48E-12 |
| 1000 | 1.79E-12 |
| 1050 | 2.15E-12 |
| 1100 | 2.56E-12 |
| 1150 | 3.03E-12 |
| 1200 | 3.56E-12 |