Thermal decomposition of formic acid at high temperatures in shock waves

Role of water in formic acid decomposition

“…They included up to two water molecules in the transition states for dehydration and decarboxylation and demonstrated that both pathways are catalyzed by water. They found that decarboxylation is the favored pathway for all cases considered, even in the absence of water, which is inconsistent with the data obtained from gas-phase experiments (Blake and Hinshelwood, 1960;Blake et al, 1971;Hsu et al, 1982;Saito et al, 1984) and the calculations by Francisco (1992) and Goddard et al (1992). Since their focus was on the water gas shift reaction rather than the formic acid intermediate, Melius et al (1990) did not make any distinction between the different isomers of formic acid.…”

“…Although many mechanisms have been suggested in the literature, including free-radical chemistry, ionic chemistry, and surface catalysis, molecular elimination is considered the most important mechanism in both the gas phase (Blake and Hinshelwood, 1960;Hsu et al, 1982;Saito et al, 1984;Goddard et al, 1992;Francisco, 1992) and in the presence of water (Ruelle et al, 1986;Melius et al, 1990). It is generally agreed that the reaction network consists of two parallel pathways:…”

“…wood, 1960; Blake et al, 1971;Hsu et al, 1982;Saito et al, 1984) and the aqueous phase (Bjerre and S~rensen, 1992;Brill et al, 1996;Yu and Savage, 1998). The gas-phase experiments show that the CO yield is substantially greater than the CO, yield, which indicates that dehydration is the primary pathway.…”

Investigations of the reaction between CH2(X̃3B1) and O2 in the temperature range 233 K ≤ T ≤ 433 K

“…It is of some interest here to notice that the thermal dissociation of HCOOH has been shown to produce CO + H 2 0 as a main channel [41,33], but virtually no OH [16], while the exact contribution of a channel to C 0 2 + H2 is not yet quite clear. The apparent activation energy for HCOOH dissociation is between 180 to 290 kJ/mol [41], which is compatible with formation of CO + H 2 0 and C 0 2 + H2, but much less than the endothermicity of ArH:98 = 466 kJ/mol for HCOOH -OH + HCO. Also, recent theoretical predictions of the potential barrier heights for HCOOH decomposition range from 264 to 285 and 273 to 297 kJ/mol, respectively, for the CO and C 0 2 forming channels [33].…”

A study of the chemical structure of laminar premixed HC(O)OH/O2/Ar flames at 1 atm

“…The reactions of formic acid monomolecular decomposition were studied experimentally under low temperature in works [7,8] and under high temperatures in works [9][10][11][12]. According to the obtained results formic acid mostly decomposes via reaction HC(O)OH=CO+H2O whereas the reaction HC(O)OH=CO2+H2 has lower contribution.…”