Unimolecular decomposition of formic acid in the gas phase--on 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.

• Authors: Ko Saito, Takanori Shiose, Osamu Takahashi, Yoshiaki Hidaka, Fuhito Aiba, Kiyohiko Tabayashi
• Journal: The journal of physical chemistry. A (J Phys Chem A) Vol. 109 Issue 24 Pg. 5352-7 (Jun 23 2005) ISSN: 1089-5639 [Print] United States
• PMID: 16839059 (Publication Type: Journal Article)