title: Gas phase hydrolysis of formaldehyde to form methanediol: impact of formic acid catalysis.
abstract: We find that formic acid (FA) is very effective at facilitating diol formation through its ability to reduce the barrier for the formaldehyde (HCHO) hydrolysis reaction. The rate limiting step in the mechanism involves the isomerization of a prereactive collision complex formed through either the HCHO···H2O + FA and/or HCHO + FA···H2O pathways. The present study finds that the effective barrier height, defined as the difference between the zero-point vibrational energy (ZPE) corrected energy of the transition state (TS) and the HCHO···H2O + FA and HCHO + FA···H2O starting reagents, are respectively only ∼1 and ∼4 kcal/mol. These barriers are substantially lower than the ∼17 kcal/mol barrier associated with the corresponding step in the hydrolysis of HCHO catalyzed by a single water molecule (HCHO + H2O + H2O). The significantly lower barrier heights for the formic acid catalyzed pathway reveal a new important role that organic acids play in the gas phase hydrolysis of atmospheric carbonyl compounds.
authors.affiliation: Chemical Sciences Division, Saha Institute of Nuclear Physics , 1/AF Bidhannagar, Kolkata-700064, India.
authors.forename: Montu K
authors.initials: MK
authors.lastname: Hazra
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Francisco
authors.forename: Amitabha
authors.initials: A
authors.lastname: Sinha