5 reactions that have to be checked in detail

[agi-jaguar]

With regard to pressure-dependent reactions, I have so far found 5 suspicious reactions, and 3 of 5 might cause significant issues.

 1. C2H3 + CH3CHO = CH3CO + C2H4 (NOx 2018, index: 373)
 2. CH2 + CH4 = CH3 + CH3 (NOx 2018, index: 62)
 3. H2CCCH = H + HCCCH (Nitrogen_Glaborg_Gimenez_et_al, index: 510)
 4. CH3 = H + CH2 (NOx 2018, index: 65)
 5. CH3 = H2 + CH (NOx 2018, index: 66)

1. C2H3 + CH3CHO = CH3CO + C2H4 (NOx 2018, index: 373)
So the source for this reaction is Chen, Song, Song, Lv, Li, Computational and Theoretical Chemistry 1075 (2016) 63–69 https://www.sciencedirect.com/science/article/abs/pii/S2210271X15004673

In NOx 2018, the A-factor is 0.16 [cm3/mol/s], but I think it should be 15.52 [cm3/mol/s] (in the paper, 2.579E-23 [cm3/molecules/s])

2. CH2 + CH4 = CH3 + CH3 (NOx 2018, index: 62)
I think the A factor should be 4.3E12 rather than 4.3E13, also Ea factor is 10030 cal/mol rather than 0.
See the source: https://ars.els-cdn.com/content/image/1-s2.0-S0360128517301600-mmc3.txt
My guess is that this reaction somehow was mistakenly considered as CH4 + singlet CH2 (i.e. CH2(S)).

CH4+CH2=CH3+CH3                      4.3E12   0.000   10030 ! 
! Bohland T Dobe S Wagner HGg BBPC 89:1110 (1985)
!
CH4+CH2(S)=CH3+CH3                   4.3E13   0.000       0 ! 
! Tsang W Hampson RF JPCRD 15:1087 1986  

3. H2CCCH = H + HCCCH (Nitrogen_Glaborg_Gimenez_et_al, index: 510)
I couldn't find the source and the reverse reaction shows TOTALLY non-reasonable behavior as below

4. CH3 = H + CH2 (NOx 2018, index: 65) & 5. CH3 = H2 + CH (NOx 2018, index: 66)
These two reactions are from the same experimental study paper by V Vasudevan, RK Hanson, DM Golden, CT Bowman, DF Davidson, J. Phys. Chem. A 2007, 111, 4062-4072.
https://pubs.acs.org/doi/full/10.1021/jp0677187

These two rate coefficients are measured at too-high temperatures (2253--3527 K). For this reason, the reverse reactions of these two rate coefficients show TOTALLY non-reasonable behavior as below

4. CH3 = H + CH2 (NOx 2018, index: 65)

5. CH3 = H2 + CH (NOx 2018, index: 66)

I guess any rate coefficients below 2000 K (maybe even up to 2500 K) are very very off from the real values. Since the reverse reactions are barrierless reactions, the rate coefficients at high T (e.g.,2000 K) shouldn't be different more than an order of magnitude from 500 K or lower T.

Any good thoughts for reactions 3,4, and 5? (Currently, I don't have any good solutions for these reactions)