有机自由基和双自由基与离子的气相反应。

Gas-phase reactions of organic radicals and diradicals with ions.

作者信息

Zhang Xu, Bierbaum Veronica M, Ellison G Barney, Kato Shuji

机构信息

Department of Chemistry and Biochemistry, University of Colorado, Boulder, 80309-0215, USA.

出版信息

J Chem Phys. 2004 Feb 22;120(8):3531-4. doi: 10.1063/1.1648019.

DOI:10.1063/1.1648019

PMID:15268514

Abstract

Reactions of polyatomic organic radicals with gas phase ions have been studied at thermal energy using a flowing afterglow-selected ion flow tube (FA-SIFT) instrument. A supersonic pyrolysis nozzle produces allyl radical (CH2CHCH2) and ortho-benzyne diradical (o-C6H4) for reaction with ions. We have observed: [CH2CHCH2 + H3O+ --> C3H6+ + H2O], [CH2CHCH2 + HO- --> no ion products], [o-C6H4 + H3O+ --> C6H5+ + H2O], and [o-C6H4 + HO- --> C6H3- + H2O]. The proton transfer reactions with H3O+ occur at nearly every collision (kII approximately with 10(-9) cm3 s(-1)). The exothermic proton abstraction for o-C6H4 + HO- is unexpectedly slow (kII approximately with 10(-10) cm3 s(-1)). This has been rationalized by competing associative detachment: o-C6H4 + HO- --> C6H5O + e-. The allyl + HO- reaction proceeds presumably via similar detachment pathways.

摘要

利用流动余辉-选择离子流管（FA-SIFT）仪器，在热能条件下研究了多原子有机自由基与气相离子的反应。一个超音速热解喷嘴产生烯丙基自由基（CH2CHCH2）和邻苯炔双自由基（o-C6H4）用于与离子反应。我们观察到：[CH2CHCH2 + H3O+ --> C3H6+ + H2O]，[CH2CHCH2 + HO- --> 无离子产物]，[o-C6H4 + H3O+ --> C6H5+ + H2O]，以及[o-C6H4 + HO- --> C6H3- + H2O]。与H3O+的质子转移反应几乎在每次碰撞时发生（kII约为10^(-9) cm3 s^(-1)）。o-C6H4 + HO-的放热质子夺取反应出乎意料地慢（kII约为10^(-10) cm3 s^(-1)）。这已通过竞争缔合脱附得到解释：o-C6H4 + HO- --> C6H5O + e-。烯丙基 + HO-反应可能通过类似的脱附途径进行。