High‐temperature rate constants for H/D + C₂H₆ and C₃H₈

Abstract

The title reactions have been studied at the CCSD(T)/aug-cc-pv∞z level of theory using saddle point geometries at B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) levels of theory. The reaction endothermicities are in good agreement with current Active Thermochemical Tables values. Theoretical rate constants were estimated using transition state theory. The theoretical rate constants are in good agreement with the present experiments and lower temperature literature data. Over the T range of the present experiments, the theoretically predicted isotope effects are close to unity.

The Measurement of the Rate Parameters for the Reactions i‐C3H and n‐C3H + HI → C3H8 + I• over the Temperature Range 293–623 K: Implications for the Standard Heat of Formation of the Propyl Radicals

“…Figure also shows the results previously published by Seetula et al for the reaction i‐C 3 H + HI → C 3 H 8 + I • . It appears that the present results exhibit a very different trend in comparison with this single study.…”

Combined Experimental and Computational Study on the Unimolecular Decomposition of JP-8 Jet Fuel Surrogates. II: n-Dodecane (n-C12H26)

“…6(b)) and, among secondary H abstractions, the reaction producing 5-dodecyl is preferred and followed by the reactions giving 5-dodecyl, then by 2-and 3-dodecyl (with similar rate constants), and finally by 4-dodecyl. The computed rate constants to form 2-and 3-dodecyl agree best with the literature data (the most accurate calculations for C3H8 84 and experimental data for C3H8, C4H10, and C5H12 [85][86] Our main conclusion is that the secondary H abstractions are feasible and form n-dodecyl radicals (n > 1). Once the n-dodecyl radicals are produced, they can rapidly undergo C-C bond βscission to yield higher alkenes together with 1-alkyl radicals:…”

“…While n-dodecyls are not expected to be formed by C-H bond cleavages in n-dodecane, they can be produced by direct hydrogen abstractions by H atoms or other radicals when those radicals appear in the reactive system. 84 The calculated rate constants for secondary H abstractions are generally higher than those for the primary hydrogen abstraction (Fig. 6(b)) and, among secondary H abstractions, the reaction producing 5-dodecyl is preferred and followed by the reactions giving 5-dodecyl, then by 2-and 3-dodecyl (with similar rate constants), and finally by 4-dodecyl.…”

Combined Experimental and Computational Study on the Unimolecular Decomposition of JP-8 Jet Fuel Surrogates. I. n-Decane (n-C10H22)

“…6 and Table 6). While n-decyls are unlikely to be formed by C-H bond cleavages in n- 81 The calculated rate constants for secondary hydrogen abstractions are similar to each other and are much higher than those for the primary hydrogen abstraction indicating that the most likely products are 2-, 3-, 4-and 5-decyl radicals (Fig. 7(c)).…”