The SO3 decay and H3NSO3 appearance were fit simulta-
neously to these equations with kf fixed at the value extrapolated
from the lower temperature data. The reaction time was
calculated using the relationship t ) z/(1.7V) where z is the
reaction distance and V is the average flow velocity.
4 The rate coefficient for SO3 wall loss was fixed at the value measured
in the absence of NH3. This value was always within 10% of
the diffusion-limited value, implying that the SO3 reaction
probability with the reactor wall was greater than 10-3. The
nonlinear regression variables included the first-order H3NSO3