Zabarnick, S., Fleming, J.W., and Lin, M.C. (1988)
Kinetics of Hydroxyl Radical Reactions with Formaldehyde and
1,3,5-Trioxane between 290 and 600 K
Int. J. Chem. Kinet. 1988, 20, 117.
Abstract
Absolute rate constants are measured for the reactions: OH + CH2O, over the
temperature range 296-576 K and for OH + 1,3,5-trioxane over the range 296-597 K.
The technique employed is laser photolysis of H2O2 or HNO3 to produce OH, and
laser-induced fluorescence to directly monitor the OH concentration. The results
fit the following Arrhenius equations: k(CH2O)=(1.66±0.20)E-11
exp[-(170±80)/RT] cm3/s and k(1,3,5-trioxane)=(1.36±0.20)E-11
exp[-(460±100)/RT] cm3/s. The transition-state theory is employed to model
the OH + CH2O reaction and extrapolate into combustion regime. The calculated
result covering 300 to 2500 K can be represented by the equation: k(CH2O)=1.2E-18
T^2.46 exp(970/RT) cm3/s. An estimate of 91±2 kcal/mol is obtained for the
first C-H bond in 1,3,5-trioxane by using a correlation of C-H bond strength with
measured activation energies.
REACTION RATE COEFFICIENTS SUGGESTED IN THIS WORK:
GRI-Mech
Number
('-' sign
means
reverse) |
Reaction |
Rate Coefficient
A T^n exp(-E/RT) |
Temperature
Range
(K) |
A
(mol,cm3,s) |
n
(T in K) |
E
(cal/mol) |
| 101 |
OH + CH2O -> HCO + H2O |
1.0E+13 |
|
170 |
296-576 |
| 101 |
OH + CH2O -> HCO + H2O |
7.23E+5 |
2.46 |
-970 |
300-2500 |