Oxidation of Reduced Sulfur Species: Carbon Disulfide

A detailed chemical kinetic model
for oxidation of CS2 has been developed, on the basis of
ab initio calculations for key reactions, including CS2 + O2 and CS + O2, and data from literature.
The mechanism has been evaluated against experimental results from
static reactors, flow reactors, and shock tubes. The CS2 + O2 reaction forms OCS + SO, with the lowest energy
path involving crossing from the triplet to the singlet surface. For
CS + O2, which yields OCS + O, we found a high barrier
to reaction, causing this step to be important only at elevated temperatures.
The model predicts low temperature ignition delays and explosion limits
accurately, whereas at higher temperatures it appears to overpredict
both the induction time for CS2 oxidation and the formation
rate of [O] upon ignition. The predictive capability of the model
depends on the accuracy of the rate constant for the initiation step
CS2 + O2, which is difficult to calculate due
to the intersystem crossing, and the branching fraction for CS2 + O, which is measured only at low temperatures. The governing
reaction mechanisms are outlined on the basis of calculations with
the kinetic model.