SOURCE:
The parameters represent the results of a 5-channel RRKM calculation, which were fit to the methanol decomposition data of Spindler et al. (1982), Dombrowsky et al. (1991), and Cribb et al. (1984), and the room temperature data for OH + CH3 of Hughes et al. (1992) and Anastasi et al. (1991). Parameters for channels 3 and 4 are estimates, guided by the 300K results of Dobe et al. (1994). Parameters for channel 0 are adapted from the calculations of Walch (1993).
The 5 reactions channels are:
Channel Reaction Reaction Number
0 CHOH + H2 (+M) <= CH3OH (+M) omitted
1 CH2(S) + H2O (+M) = CH3OH (+M)
2 OH + CH3 (+M) = CH3OH (+M) 95
3 H + CH2OH (+M) = CH3OH (+M) 59
4 H + CH3O (+M) = CH3OH (+M) 63
Related chemical activation reactions:

61. H + CH2OH -> OH + CH3
62. H + CH2OH -> CH2(S) + H2O
64. H + CH3O -> H + CH2OH
66. H + CH3O -> OH + CH3
67. H + CH3O -> CH2(S) + H2O
97. OH + CH3 -> CH2(S) + H2O
288. OH + CH3 -> H2 + CH2O
293. CH2(S) + H2O -> H2 + CH2O
Rate coefficients computed by 5-channel RRKM calculation.

<delta-E> = 0.35 kcal/mol
The Lennard-Jones parameters: sigma(CH3OH-Ar) = 3.584 A, epsilon = 212 K
k_o(N2)/k_o(Ar) = 1.43
Active molecular K-rotor 4.11 amu-A^2, sigma = 1
Torsion 0.705 amu-A^2, sigma = 3
Adiabatic I = 18.8 amu-A^2, sigma = 1
v = 3680, 3000, 2960, 2840, 1480, 1480, 1450, 1350, 1160, 1060, 1030 cm^(-1)

Transition state 0     CHOH + H2
delta-E(0 K) = 0.0 kcal/mol; delta-H(0 K) = -86.96 kcal/mol
Adiabatic I+ = 24.45 amu-A^2 , sigma = 1
v = 3720, 2880, 2090, 1410, 1350, 1210, 1160, 1010, 840, 560, 460 cm^(-1)
Active 1-D rotor I = 4.11 amu-A^2; sigma = 1

Transition state 1     CH2(S) + H2O
delta-E(0 K) = 0.0 kcal/mol; delta-H(0 K) = -90.76 kcal/mol
Adiabatic I+ = 122amu-A^2 at 1000K, 141 at 400K, 103.5 at 2000K; sigma = 1
(These values relative to the molecule are used for the Waage-Rabinovitch factor.)
v = 3760, 3660, 3070, 3020, 1600, 1400 cm^(-1)
Active 1-D rotors I = 1.46, 0.354 amu-A^2; sigma = 2,2
2-D hindered rotors I = 0.829, 0.649 amu-A^2 (90%) at 1000K; 0.994, 0.811 at 400K (80%); 0.586, 0.459 at 2000K (95%); sigma = 1,1

Transition state 2      OH + CH3
delta-E(0 K) = 0.0 kcal/mol; delta-H(0 K) = -90.48 kcal/mol
Adiabatic I+ = 122 amu-A^2 at 1000K, 141 at 400K, 103.5 at 2000K; ssigma = 1
v = 3570, 3180, 3180, 3000, 1380, 1380, 580 cm^(-1)
Active 1-D rotor I = 4.11 amu-A^2, sigma = 1
2-D hindered rotors I = 0.79, 0.396 amu-A^2 (80%) at 1000K; 0.93, 0.67 at 400K (70%); 0.56, 0.28 at 2000K(90%); sigma = 1,1

Transition state 3     H + CH2OH
delta-E(0 K) = 0.0 kcal/mol; delta-H(0 K) = -94.84 kcal/mol
Adiabatic I+ = 18.8 amu-A^2, sigma = 1
v = 3640, 3000, 3000, 1460, 1330, 1180, 1050, 950, 290 cm^(-1)
Active 1-D rotor I = 4.11 amu-A^2, sigma = 1
2-D hindered rotor I = 1.12 amu-A^2 (94%), sigma = 1

Transition state 4     H + CH3O
delta-E(0 K) = 0.0 kcal/mol; delta-H(0 K) = -102.49 kcal/mol
Adiabatic I+ = 18.8 amu-A^2, sigma = 1
v = 3320, 3320, 3220, 1660, 1600, 1580, 1160, 1060, 720 cm^(-1)
Active 1-D rotor I = 4.11 amu-A^2, sigma = 1
2-D hindered rotor I = 1.12 amu-A^2 (94%), sigma = 1

COMMENTS:
Methanol decomposition to CHOH + H2 (channel 0) is a very minor pathway except at very low pressure and low temperature, and this reaction is not included in GRI-Mech. The chemical activation steps to these products, 288 and 293, have been added. Formaldehyde is assumed as the final product of these one-way reactions, from rapid isomerization of CHOH.
The channel 1 parameters reflect a fit to the low pressure 300 K data for reaction
97. OH + CH3 -> CH2(S) + H2O.
from Hughes et al. (1992), Hack et al. (1988), and Staker et al. (1991). The results of Oser et al. (1992) and Bott and Cohen (1991) (at 1200 K) favor a lower value.
The recent study by DeAvillezPereira et al (1998) analyzes reaction 97 as a 4 channel system, up to 1000K, but did not examine the high temperature decomposition data.
The channel 2 parameters were selected to match the high pressure 300 K data of Hughes et al. (1992) and Anastasi et al. (1991) and the decomposition data of Spindler et al. (1982), Dombrowsky et al. (1991), and Cribb et al. (1984).
The channel 3 hindrance parameter was chosen to fit the 300K result of Dobe et al. (1994) for reaction 61. H + CH2OH -> OH + CH3, and was also assigned to channel 4.
Results for methanol decomposition, k_o in Ar at 1800 K:
Reference cm3/mol s
GRI-Mech 2.4?E8
Cribb et al. (1984) 5.4E8
Spindler et al. (1982) 1.0E9
Hidaka et al. (1989) 3.2E8
The pressure broadening is expressed in the Troe form.

REFERENCES:

Spindler et al. (1982)
Spindler, K., and Wagner, H.G. (1982) Ber. Bunsenges. Phys. Chem. 86, 2.
Dombrowsky et al. (1991)
Dombrowsky, C., Hoffmann, A., Klatt, M., and Wagner, H. Gg. (1991) Ber. Bunsenges. Phys. Chem. 95, 1685.
Cribb et al. (1984)
Cribb, P.H., Dove, J.E., and Yamazaki, S. (1984) 20th Symposium(International) on Combustion, p. 779.
Hughes et al. (1992)
Hughes, K.J., Pereira, A.R., and Pilling, M.J. (1992) Ber. Bunsenges. Phys. Chem. 96, 1352.
Hack et al. (1988)
Hack, W., Wagner, H.Gg., and Wilms, A. (1988) Ber. Bunsenges. Phys. Chem. 92, 620.
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Hidaka, Y., Oki, T., Kawano, H., and Higashihara, T. (1989) J. Phys. Chem. 93, 7134.
Staker et al. (1991)
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Oser et al. (1992)
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Bott and Cohen (1991)
Bott, J.F., and Cohen, N. (1991) Int. J. Chem. Kinet. 23, 1017.
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Anastasi, C., Beverton, S., Ellermann, T., and Pagsberg, P. (1991) J. Chem. Soc. Farad. Trans. 87, 2325.
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Dobe, S., Berces, T., and Szilagyi, I. (1991) J. Chem. Soc. Farad. Trans. 87, 2331.
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DeAvillez Pereira, R., Baulch, D. L., Pilling, M. J., Robertson, S. H., and Zeng, G. (1998) J. Phys. Chem. 101, 9681.