کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4764502 1423550 2018 18 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Reaction mechanism, rate constants, and product yields for the oxidation of Cyclopentadienyl and embedded five-member ring radicals with hydroxyl
ترجمه فارسی عنوان
مکانیزم واکنش، ثابت سرعت و عملکرد محصول برای اکسیداسیون سیکلوپنتادیانیل و رادیکال های حلقه ای پنج عضو با هیدروکسیل
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی

Potential energy surfaces for the C5H5 + OH and C15H9 + OH reactions have been studied by ab initio calculations at the CCSD(T)-F12/cc-pVTZ-f12//B3LYP/6-311G(d,p) and G3(MP2,CC)//B3LYP/6-311G(d,p) levels of theory, respectively, in order to unravel the mechanism of oxidation of the cyclopentadienyl radical and five-member-ring radicals embedded in a sheet of six-member rings with OH. The VRC-TST approach has been employed to compute high-pressure-limit rate constants for barrierless entrance and exit reaction steps and multichannel/multiwell RRKM-ME calculations have been utilized to produce phenomenological pressure- and temperature-dependent absolute and individual-channel reaction rate constants. The calculations allowed us to quantify relative yields of various products in a broad range of conditions relevant to combustion and to generate rate expressions applicable for kinetic models of oxidation of aromatics. The C5H5 + OH reaction is shown to proceed either by well-skipping pathways without stabilization of C5H6O intermediates leading to the bimolecular products ortho-C5H5O + H, C5H4OH (hydroxycyclopentadienyl) + H, and C4H6 (1,3-butadiene) + CO, or via stabilization of the C5H6O intermediates, which then undergo unimolecular thermal decomposition to ortho-C5H5O + H and C4H6 + CO. The well-skipping and stabilization/dissociation pathways compete depending on the reaction conditions; higher pressures favor the stabilization/dissociation and higher temperature favor the well-skipping channels. For the C15H9 + OH reactions, the results demonstrate that embedding decreases the oxidation rate constants and hinder the decarbonylation process; the removal of CO grows less likely as the number of common edges of the five-member ring with the surrounding six-member rings increases.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Combustion and Flame - Volume 187, January 2018, Pages 147-164
نویسندگان
, , ,