Rate constant of the gas phase reaction of SO3 with H2O

Abstract

The rate constants for the reaction of SO3 with H2O in He and in N2 were measured at total pressures from 1–10 Torr in a flow tube at room temperature. The concentration of SO3 was monitored by photofragment emission produced by 147 nm excitation. Dependencies of apparent reaction rates on wall conditions and reaction tube sizes were investigated. At total He pressures of 1–10 Torr, a value of (5.7±0.9)×10−15 cm3 /s was obtained for the upper limit of the homogeneous gas phase reaction rate constant. This rate value is more than two orders of magnitude lower than the previously published value, but it is consistent with the theoretical calculation provided in this paper.

Present OH measurement limits and associated uncertainties

“…The results of several laboratory studies will be considered first, followed by a discussion of some interesting new field measurement data. As discussed previously, the reaction rate of SO 3 with H20 to form H2SO 4 is, at best, slow (k 3 _• 5.7 x 10 -15 cm3 s -1) [Wang et al, 1988] and rather uncertain. The reaction rate constant k 3 is not, however, used in the calculation of OH concentration.…”

Fate of ammonia in the atmosphere?a review for applicability to hazardous releases

“…For a long time it was assumed that the reaction of SO3 with water should be so fast that reaction with other atmospheric components could be neglected. However, in 1988, Wang et al [90] found that the gas-phase reaction of SO3 and H 2 0 was much slower than generally assumed, with a second-order rate constant estimated to be 5. [92] found that the gas-phase reaction of ammonia with SO3 was faster than the gas-phase reaction of SO3 with water by almost four orders of magnitude: 6.9xl0 -u cm 3 mol -1 s -1 .…”

Formic Acid Catalyzed Gas‐Phase Reaction of H2O with SO3 and the Reverse Reaction: A Theoretical Study

“…Therefore, analysis of the rate constant is based on the results obtained via Equation (5). The reported upper limit of the rate constant for the reaction of SO 3 with H 2 O is 2.4 10 À15 cm 3 molecule À1 s À1 at 298 K, [77,78] which is about 10…”