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Author(s):   Park, J.; Xu, Z.F.; Lin, M.C.
Title:   Thermal decomposition of ethanol. II. A computational study of the kinetics and mechanism for the H+C2H5OH reaction
Journal:   J. Chem. Phys.
Volume:   118
Page(s):   9990 - 9996
Year:   2003
Reference type:   Journal article
Squib:   2003PAR/XU9990-9996

Reaction:   C2H5OH + → Other Products + H2
Reaction order:   2
Temperature:   300 - 3000 K
Rate expression:   2.74x10-13 [cm3/molecule s] (T/298 K)3.12 e-12538 [J/mole]/RT
Category:  Theory
Data type:   Ab initio
Comments:   Ab initio study of Ethanol + H reaction channels. Rate constants based on ab initio transition states. Ab initio energies calculated using G2M method with B3LYP/6-311+G(d,p). Rate expressions calculated using Truhlars Polyrate program using SCT/CVT method (small curvature tunnelling correction/canonical variational transition state theory).

Found barriers of
7.2 kcal/mol for CH3CH(OH)* + H2 channel
13.3 kcal/mol for CH2OHCH2* + H2 channel
15.0 kcal/mol for CH3CH2O* + H2 channel
27.2 kcal/mol for CH3CH2* + H2O channel
The first channel dominates at all temperatures, the second channel begins to contribute at about 1000 K and is roughly equal at 3000 K, the third channel is <5% even at 3000 K. The fourth channel is kinetically insignificant.

There is a disagreement between the calculated values for the total rate with experimental measurements by Adler and Wagner Ber. Buns. Phys. Chem. 77, 712 (1973), the calc values being 2-3 times lower. The current authors attribute the difference to incorrect assumptions regarding secondary reactions in the experimental measurements, and they employing modeling to demonstrate such.

View full bibliographic record.


Rate constant values calculated from the Arrhenius expression:

T (K)k(T) [cm3/molecule s]
300 1.84E-15
400 1.58E-14
500 6.75E-14
600 1.97E-13
700 4.57E-13
800 9.07E-13
900 1.61E-12
1000 2.65E-12
1100 4.10E-12
1200 6.02E-12
1300 8.52E-12
1400 1.17E-11
1500 1.55E-11
1600 2.02E-11
1700 2.58E-11
1800 3.24E-11
1900 4.01E-11
2000 4.90E-11
2100 5.92E-11
2200 7.07E-11
2300 8.36E-11
2400 9.82E-11
2500 1.14E-10
2600 1.32E-10
2700 1.52E-10
2800 1.74E-10
2900 1.97E-10
3000 2.23E-10