Reilly Neil J, da Silva Gabriel, Wilcox Callan M, Ge Zijun, Kokkin Damian L, Troy Tyler P, Nauta Klaas, Kable Scott H, McCarthy Michael C, Schmidt Timothy W
Department of Chemistry, University of Massachusetts Boston , 100 Morrissey Boulevard, Boston, Massachusetts 02125, United States.
Department of Chemical Engineering, The University of Melbourne , Parkville, Victoria 3010, Australia.
J Phys Chem A. 2018 Feb 8;122(5):1261-1269. doi: 10.1021/acs.jpca.7b11914. Epub 2018 Jan 29.
The products of an electrical discharge containing toluene are interrogated using resonance-enhanced multiphoton ionization and laser-induced fluorescence spectroscopies. A previously unreported electronic spectrum recorded at m/z = 105, with a putative origin band at 26053 cm, is assigned to methyltropyl radical, which appears to be a major product of the toluene discharge, plausibly arising from CH insertion. All three o-, m-, and p-xylyl isomers are also identified. These isomers are detected in electrical discharges containing various xylenes, where it is also found that interconversion occurs: A discharge of o-xylene produces some m-xylyl; a discharge of m-xylene produces some o-xylyl; and a discharge of p-xylene produces all three isomers. No α-methylbenzyl was detected, but styrene was. These observations are supported by state-of-the-art quantum chemical calculations, which reveal an isomerization pathway between methyltropyl and xylyl radicals for which there is no analogue in the canonical tropyl-benzyl isomerization.
利用共振增强多光子电离和激光诱导荧光光谱对含有甲苯的放电产物进行研究。记录到一个先前未报道的质荷比为(105)的电子光谱，其推定的起始带位于(26053 cm^{-1})，该光谱被归属于甲基环庚三烯基自由基，它似乎是甲苯放电的主要产物，可能源于(CH)插入反应。同时还鉴定出了邻、间、对三种二甲苯异构体。在含有各种二甲苯的放电中检测到了这些异构体，并且还发现了它们之间的相互转化：邻二甲苯放电会产生一些间二甲苯异构体；间二甲苯放电会产生一些邻二甲苯异构体；对二甲苯放电会产生所有三种异构体。未检测到α - 甲基苄基，但检测到了苯乙烯。这些观测结果得到了先进的量子化学计算的支持，该计算揭示了甲基环庚三烯基和二甲苯自由基之间的异构化途径，这在经典的环庚三烯基 - 苄基异构化中没有类似情况。
