Gas-Phase Reaction of Hydroxyl Radical with Hexamethylbenzene

被引：13

作者：

Loison, Jean-Christophe ^{[1
,2
]}

Rayez, Marie-Therese ^{[1
,2
]}

Rayez, Jean-Claude ^{[1
,2
]}

Gratien, Aline ^{[1
,2
]}

Morajkar, Pranay ^{[1
,2
,3
,4
]}

Fittschen, Christa ^{[3
,4
]}

Villenave, Eric ^{[1
,2
]}

机构：

[1] Univ Bordeaux, ISM, UMR 5255, F-33400 Talence, France

[2] CNRS, ISM, UMR 5255, F-33400 Talence, France

[3] Univ Lille, PC2A, UMR 8522, F-59655 Villeneuve Dascq, France

[4] CNRS, PC2A, UMR 8522, F-59655 Villeneuve Dascq, France

来源：

JOURNAL OF PHYSICAL CHEMISTRY A | 2012年 / 116卷 / 50期

关键词：

PHOTOIONIZATION CROSS-SECTIONS; ELECTRON-IMPACT IONIZATION; H-ATOM ABSTRACTION; RATE CONSTANTS; OH RADICALS; P-XYLENE; KINETICS; BENZENE; HYDROCARBONS; THRESHOLD;

D O I：

10.1021/jp307568c

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Aromatic hydrocarbons are important components of polluted ambient air. The reaction of OH radicals with hexamethylbenzene (HMB) is a prototype system to study ipso addition leading eventually to dealkylation. We have investigated the OH + HMB and OD + HMB reactions between 323 and 433 K using a discharge fast-flow reactor coupled to a time-of-flight mass spectrometer with single-photon VUV photoionization (10.54 eV). The H atom abstraction channel has been found to be equal to (13.7 +/- 4.4) % at 330 K leading to (11.1 +/- 3.6) % at 298 K, higher than predicted by commonly used structure-reactivity relationships. The back dissociation rate constant has also been measured and has been found to be smaller than the rate of other aromatic hydrocarbons, in good agreement with density functional theoretical calculations. The dealkylation channel, leading to pentamethylphenol (PMP) + CH3, is always found to be the minor channel, estimated inferior to 2% at 298 K.

引用

页码：12189 / 12197

页数：9

共 50 条

[1] Extent of H-atom abstraction from OH plus p-cymene and upper limits to the formation of cresols from OH plus m-xylene and OH plus p-cymene [J].