Shock tube investigation of major pathways in the high-temperature pyrolysis of benzene

Journal Article · Thu May 09 04:00:00 EDT 1985 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100256a043· OSTI ID:5045692

Kiefer, J H; Mizerka, L J; Patel, M R; Wei, H C

The high-temperature pyrolysis of benzene, 1 and 2 mol % in krypton, has been studied in the shock tube with the laser-schlieren technique over 1900-2400 K and 0.2-1.0 atm. A completely successful modeling of the density gradient profiles and some time-of-flight mass spectra is achieved with a simple radical chain mechanism consisting of essentially just four reactions. The dissociation is solely CH bond scission (M) + C/sub 6/H/sub 6/ ..-->.. C/sub 6/H/sub 5/ + H + (M) whose rates are strongly dependent on both temperature and pressure in this range; this reaction is near second order for T > 2300 K. An RRKM fit to these data suggests a barrier of 112 +/- 2 kcal/mol, which corresponds to ..delta..H/sub f//sup 0//sub 298/ = 80 +/- 2 kcal/mol for the phenyl radical heat of formation, and an average collisional energy transfer of (-..delta..E)/sub all/ = 70 cm/sup -1/. The extrapolated K/sub infinity/ for this reaction is 2 x 10/sup 17/ exp(-118000 (cal)/RT) s/sup -1/ (1900-2400 K). The model also indicates a rate constant of 2.5 x 10/sup 14/ exp(-16000 (cal)/RT cm/sup 3//(mol s) (1900-2200 K) for the abstraction H + C/sub 6/H/sub 6/ ..-->.. C/sub 6/H/sub 5/ + H/sub 2/. 31 references, 9 figures, 3 tables.

• Research Organization: Univ. of Illinois, Chicago
• DOE Contract Number: AC02-78ER04759
• OSTI ID: 5045692
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 89:10; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ACTIVATION ENERGY
AROMATICS
ARYL RADICALS
BENZENE
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COLLISIONS
DATA
DECOMPOSITION
ELEMENTS
ENERGY
ENERGY TRANSFER
ENTHALPY
EXPERIMENTAL DATA
FLUIDS
FORMATION HEAT
GASES
HYDROCARBONS
INFORMATION
KINETICS
KRYPTON
LASERS
LOW PRESSURE
MATHEMATICAL MODELS
MEDIUM PRESSURE
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
PHENYL RADICALS
PHOTOGRAPHY
PHYSICAL PROPERTIES
PRESSURE DEPENDENCE
PYROLYSIS
RADICALS
RARE GASES
REACTION HEAT
REACTION KINETICS
SCHLIEREN METHOD
SHOCK TUBES
TEMPERATURE DEPENDENCE
THERMOCHEMICAL PROCESSES
THERMODYNAMIC PROPERTIES
VERY HIGH TEMPERATURE