Study of reaction pathway and kinetics of Cl atom with HCOOH

At the g2 // ump2/6-311 + g** level, the reaction pathway of cl with hcooh oxidation reaction was discussed in this paper. the dominant initial step is cl atom attacking h on c in trans-formic acid through a barrier hight of 16.7 kj/mol to form cis-hoco radical r1a. two multi-step pathways are related to a secondary reaction of cis-hoco radical converting to trans-hococl by another cl atom through the secondary reaction of r1a(1) and r1a(2), then trans-hococl can dissociate to the final product co(2). for r1a(1) or r1a(2) channel, the adduct forming step has no barrier but the cis to trans conversion step has a small barrier. the final step of dissociation of trans-hococl needs high activation energy of 131.0 kj/mol at the g2 // ump2/6-311 + g** level. the calculated tst rate constants of the initial h-abstraction step are in good agreement with the experimental result. the h-abstraction reaction of formic acid dimer with cl atom was also considered.