The water-catalyzed mechanism for the pyrolysis of formic acid was studied
by the ab initio quantum chemical calculations. The dehydration and decarbo
xylation reactions of formic acid occur via five- and six-member-ring hydro
gen bonding complexes and transition states, respectively. The role of the
water molecule is to serve as a proton relay acting simultaneously as a hyd
rogen-atom donor and acceptor. The corresponding potential energy surface w
as obtained at G2(MP2) level of theory. The large scatter in the reported e
xperimental activation barriers for the dehydration and decarboxylation rea
ction of formic acid was explained reasonably. (C) 1999 Elsevier Science B.
V. All rights reserved.