Unimolecular Decomposition of Formic Acid in the Gas PhaseOn the Ratio of the Competing Reaction Channels

Abstract

The thermal decomposition of formic acid was reinvestigated in the gas phase using two types of shock tubes. It was confirmed that the unimolecular decomposition proceeds through a main channel of dehydration (k1) and a minor decarboxylation channel (k2). This result is in good agreement with our previous study (J. Chem. Phys. 1984, 80, 4989). Furthermore, it was confirmed that the dehydration process is in the second-order region and that the decarboxylation is in the falloff region, in the temperature range of 1300-2000 K and over the total density of (0.5-2.5) x 10(-5) mol cm(-3). The experimental ratios between the two channels, k2/k1, are compared with those of theoretical calculations by conventional transition state theory and the Rice-Ramsperger-Kassel-Marcus theory.

A Computational Study on the Decomposition of Formic Acid Catalyzed by (H2O)x, x = 0−3: Comparison of the Gas-Phase and Aqueous-Phase Results

“…The predicted rate constants for unimolecular dehydration and decarboxylation in the gas phase are given by k 1 0 ) 4.05 × 10 15 exp(-52.98 kcal mol -1 /RT) cm 3 mol -1 s -1 and k 2 0 ) 1.69 × 10 15 exp(-51.11 kcal mol -1 / RT) cm 3 mol -1 s -1 , which are in good agreement with the experimentalresults. 5,6,34 ThecalculatedCO/CO 2 ratio,13.57-13.90, between 1300 and 2000 K, is in good agreement with the experimental ratio of 10 measured by Hsu et al 5…”

Dehydrogenation of formic acid catalyzed by magnesium hydride anions, HMgL2− (L=Cl and HCO2)

“…In the gas phase, in the absence of catalysts, the dehydration channel (Reaction (1), Fig. 1) is the dominant reaction [1], consistent with a lower activation energy, as predicted by DFT calculations [2]. A number of studies have demonstrated that metal catalysts can favour the decarboxylation of formic acid (Reaction (2), Fig.…”

“…1) continue to attract considerable attention, especially within the context of designing metal catalysts to direct a specific reaction channel. Reactions (1) and (2) represent the two main decomposition channels of formic acid and have been widely studied experimentally [1] and theoretically [2]. In the gas phase, in the absence of catalysts, the dehydration channel (Reaction (1), Fig.…”

Unimolecular decomposition of formic and acetic acids: A shock tube/laser absorption study

“…A number of experimental [6][7][8][9][10][11] and theoretical [12][13][14][15] studies have been carried out on the decomposition of formic acid, including three shock tube studies. Hsu et al [6] studied the decomposition of formic acid using infrared (IR) laser absorption of CO.…”