Reaction Kinetics of PO₂Cl^-, PO₂Cl₂^-, POCl₂^-, and POCl₃^- with O₂ and O₃ from 163 to 400 K

Abstract

Rate constants and product ion branching fractions for the gas-phase reactions of O2 and O3 with the anions (a) PO2Cl-, (b) POCl3 -, (c) POCl2 -, and (d) PO2Cl2 - were measured in a selected-ion flow tube (SIFT). The kinetics were measured at temperatures of 163−400 K and a He pressure of 0.4 Torr. Only PO2Cl- reacts with O2 to a measurable extent, having k(163−400 K) = 1.1 × 10-8(T/K)-1.0 cm3 molecule-1 s-1, while O3 reacts with all of the anions except PO2Cl2 -. The fitted rate constant expressions for the O3 reaction with anions a−c are as follows: k a(163−400 K) = 3.5 × 10-6(T/K)-1.6, k b(163−400 K) = 4.0 × 10-7(T/K)-1.2, and k c(163−400 K) = 3.7 × 10-7(T/K)-1.4 cm3 molecule-1 s-1. Calculations were performed at the G3 level of theory to obtain optimized geometries, energies, and electron affinities (EAs) of the reactant and product species, as well as to determine the reaction thermochemistry to help understand the experimental results. The PO x Cl y - anions that have lower electron binding energies (eBE) and higher spin multiplicities are more reactive. The doublets are more labile than the singlets. How the extra electron density is distributed in the anion does not predict the observed reactivity of the ion. The reactions of PO2Cl- with O2 and O3 yield predominantly PO3 - and PO4 -. The reaction of POCl2 - with O3 yields mostly Cl- and PO2Cl2 -, while the POCl3 - reaction with O3 yields mostly O3 - and PO2Cl2 -.

Bond strengths in POCl3−, POCl2−, and PSCl2−

“…The electron affinities of POCl 2 and POCl 3 were measured to be 3.83 and 1.41 eV by determining the thresholds for anion formation upon charge transfer from Cs to POCl 3 [6]. The corresponding values calculated at the G2 level (3.71 and 1.50 eV) [7] and G3 level (3.73 and 1.59 eV) [8] are in reasonable agreement with the experimental results. G3 calculations have also been performed on PSCl 2 , PSCl 3 , and their anions [5], but experimental results are lacking.…”

“…Other computational results for several of these species have been reported previously [5,8,14], but not at a consistent computational level. The bond lengths calculated with the B3LYP/aug-cc-pVTZ method are slightly longer than the experimental values, which is typical [14,27].…”

“…The calculated atomic charges and spin densities for the three chlorine atoms (Table 4) are essentially identical. Fernandez et al, however, calculated a moderate difference in the MP2/6-311+G(d) NBO populations of the chlorine atoms (−0.492 for two atoms and −0.404 for one) [8].…”

Conversion of Methane to Methanol: Nickel, Palladium, and Platinum (d9) Cations as Catalysts for the Oxidation of Methane by Ozone at Room Temperature

“…Ozone was generated in a O3V-0, OREC Inc. model laboratory ozone generator. [27] Oxygen from Liquid Carbonic was used directly.…”

Dissociative recombination of OPCl+ and OPCl2+: Pushing the upper mass limit at CRYRING

“…For the indirect mechanism, this dependence can be as steep as l/7^'\ The obtained temperature dependencies [Eqs. (6) and (8)] imply that the indirect mechanism plays a significant role in the DR reaction of both OPCl + and OPCl 2 + . It is noted that the DR rate constants at 300 K for two other heavy triatomic molecular ions 0 3 + and N 3 + are reported to be 7.37 X 10~7 and 6.47 X 10" 7 cm 3 s" 1 pounds where the rate constants increase in the order <x(X 2 + ) < a(X, + ) < a(X 4 + ) (X=0 or N).…”