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Experimental and theoretical studies on the reaction of H atom with C 3 H 6
Author(s) -
Chen WeiYu,
Nguyen TrongNghia,
Lin MingChang,
Wang NiannShiah,
Matsui Hiroyuki
Publication year - 2021
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.21471
Subject(s) - chemistry , transition state theory , arrhenius equation , reaction rate constant , hydrogen atom , carbon atom , hydrogen , atmospheric temperature range , branching (polymer chemistry) , thermodynamics , atom (system on chip) , bar (unit) , activation energy , atomic physics , kinetics , organic chemistry , ring (chemistry) , physics , alkyl , quantum mechanics , meteorology , computer science , embedded system
A comprehensive study on the reaction of H + C 3 H 6 has been conducted in order to clarify the temperature and pressure dependence of product branching. Site‐specific rate of addition of a hydrogen atom to the center carbon is measured by a comparative method for the evolutions of H atoms behind reflected shock waves. The rate constant for the addition to the center carbon can be given by ln( k 1‐2 /cm 3 molecule –1 s –1 ) = – (1.67 ± 0.65) × 10 3 T –1 – (24.18 ± 0.55) for H + C 3 H 6 → n‐C 3 H 7 * → products ( T = 1065‐1306 K) without pressure dependence for P = 1‐2 bar. Theoretical calculation was conducted to evaluate the pressure dependence of the product branching for the H + C 3 H 6 reaction by using transition‐state theory and RRKM theory based on quantum‐chemical calculations of potential‐energy surfaces. The result indicates that transition of the main reaction channel from addition to the terminal carbon in the low temperature range to the central carbon at moderate pressures (0.001‐10 bar) and elevated temperatures causes S‐shaped non‐Arrhenius temperature dependence of the total reaction rate against T –1 ; at the transition temperature, a strong pressure dependence was predicted. Our experimental result of k 1‐2 agrees very well with the predicted value and available experimental data. The predicted rate constant ratio for the terminal versus nonterminal additions at the high‐pressure limits agrees well with the temperature dependence reported by Manion and Awan for the analogous H + C 4 H 8 reaction. Furthermore, the importance of H‐abstraction reactions at elevated temperatures from three different sites of C 3 H 6 was predicted in this calculation. For kinetic modeling of combustion and pyrolysis of hydrocarbons, we have recommended the rate constants for the 3 abstraction reactions as well as for the production of i‐ and n‐C 3 H 7 radicals by addition reactions at the high‐ and low‐pressure limits over the temperature range of 300‐2000 K.