,
Formation of carbonyl sulfide (OCS) from carbon monoxide and sulfur vapor and applications to Venus
Icarus, 130 (2): 495--504 (1997)
Аннотация
We use gas chromatography to identify and measure the amounts of carbonyl
sulfide (OCS) formed in a gas-flow system via the net thermochemical
reactions 1 SO2 + 3 CO = OCS + 2 CO2 2 3 FeS2 (pyrite) + 4 CO2 +
2 CO = Fe3O4 (magnetite) + 6 OCS 3 2 CO + S-2, = 2 OCS at temperatures
of 470-612 degrees C and ambient atmospheric pressure. The goal of
our work is to evaluate the importance of reactions (1) to (3), which
have been proposed as potential sources of OCS in Venus' lower atmosphere.
Our results show OCS formation by reaction (3), but not by reactions
(1) or (2) under our experimental conditions. Based on our results,
experimental data from the literature, and theoretical models in
the literature, we conclude that (1) the reaction of S-2 and CO is
an important source of OCS in Venus' lower atmosphere, and (2) probably
neither reaction (1) nor reaction (2) is an important source of OCS
on Venus. Finally, we use thermodynamic data for reaction (3) and
Venera spacecraft observations of CO and sulfur vapor at 0-12-km
altitude to calculate an OCS equilibrium abundance of 1-14 ppmv,
with a nominal value of 5 ppmv, for reaction (3) near Venus' surface.
(C) 1997 Academic Press.
