Formation of Pyrylium from Aromatic Systems with a Helium:Oxygen Flowing Atmospheric Pressure Afterglow (FAPA) Plasma Source
作者:Sunil P. Badal、Tyree D. Ratcliff、Yi You、Curt M. Breneman、Jacob T. Shelley
DOI:10.1007/s13361-017-1625-z
日期:2017.6.1
reaction has not been shown before, the reaction is rapid and efficient. Potential reactant species, which could lead to pyrylium formation, were determined from reagent-ion mass spectra. Thermodynamic evaluation of reaction pathways was aided by calculation of the formation enthalpy for pyrylium, which was found to be 689.8 kJ/mol. Based on these results, we propose that this reaction is initiated by
探索了氧气添加对氦基流动大气压余辉(FAPA)电离源的影响。少量掺入氦放电气体中的氧气导致质子化水簇的丰度增加了至少三倍。对于小的极性分析物,例如甲醇和丙酮,也观察到质子化分析物信号的相应增加。同时,大多数其他反应离子(例如O2 +,NO +等)在放电气体中甚至含有0.1%v / v的氧气时,其丰度也会显着降低。有趣的是,当对包含芳香族成分的分析物进行He:O2-FAPA处理时,会产生独特的(M + 3)+离子,而分子或质子化的分子离子却很少被检测到。精确质量测量表明,这些(M + 3)+离子对应于(M-CH + O)+,最可能的结构是吡啶鎓。与市场上可买到的盐相比,通过(M + 3)+离子的串联质谱进一步证实了基于吡咯鎓的离子的存在。最后,在气相中快速有效地生产吡啶鎓用于将苯转化为吡啶。尽管该吡啶鎓形成反应以前没有显示,但该反应是快速而有效的。从试剂离子质谱图中确定了可能导致吡啶鎓形成的