US EPA

2857331 

Journal Article 

Reactivity of C2H5+ with benzene: formation of ethylbenzenium ions and implications for Titan's ionospheric chemistry 

Zabka, J; Polásek, M; Ascenzi, D; Tosi, P; Roithová, J; Schröder, D 

2009 

1 

Journal of Physical Chemistry A
ISSN: 1089-5639
EISSN: 1520-5215 

AMER CHEMICAL SOC 

WASHINGTON 

113 

42 

11153-11160 

English 

19642632 

10.1021/jp905052h 

WOS:000270670700008 

https://www.scopus.com/inward/record.uri?eid=2-s2.0-70350140203&doi=10.1021%2fjp905052h&partnerID=40&md5=0f212c300ab2cf109f3e4ec815bf7814
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The reaction of ethyl cation with benzene has been investigated in a combined experimental and theoretical approach. Under single collision conditions, proton transfer affording protonated benzene concomitant with neutral ethene represents the major reaction channel. From pressure-dependent measurements, an absolute cross section of 7 +/- 2 A(2) at hyperthermal energies (about 1.0 eV in the center of mass frame) is derived for this channel, from which a phenomenological rate constant of about 2.9 x 10(-10) cm(3) s(-1) is estimated at low energies. The energy behavior of the cross section as well as several side reactions leading to C-C coupling imply that the reaction of C(2)H(5)(+) with C(6)H(6) proceeds via a long-lived association product, presumably the covalently bound protonated ethylbenzene (ethylbenzenium ion). With regard to chemical processes in the atmosphere of Titan, present results imply that termolecular association of C(2)H(5)(+) with benzene to produce protonated ethylbenzene is very likely to occur. The condensation of alkyl cations with arenes thus provides an alternative route for the growth of larger hydrocarbon molecules.