Mass-Spectrometric Study on Ion–Molecule Reactions of CF<sub>3</sub><sup>+</sup>with Monosubstituted Benzenes Carrying a Carbonyl Group at Near-Thermal Energies
作者:Masaharu Tsuji、Masato Aizawa、Yukio Nishimura
DOI:10.1246/bcsj.69.1055
日期:1996.4
The gas-phase ion–molecule reactions of CF3+ with five monosubstituted benzenes carrying a carbonyl group (PhCOX: X = H, CH3, C2H5, OCH3, OC2H5) have been studied at near-thermal energies using an ion-beam apparatus. The major product channel for PhCHO, PhCOCH3, and PhCOOCH3 is electrophilic addition to the O-atom leading to initial adduct ions, which are 80.3—95.0% of the total product ions. Although no initial adduct ions are observed for PhCOC2H5 and PhCOOC2H5, major product ions are formed by electrophilic addition to the O-atom followed by dissociation and molecular eliminations. The reaction mechanism is discussed based on product ion distributions and semi-empirical calculations of the energies of intermediates and products. The results obtained are compared with reported ion-cyclotron-resonance data for aliphatic carbonyl compounds.
利用离子束装置研究了 CF3+ 与带有羰基的五种单取代苯(PhCOX:X = H、CH3、C2H5、OCH3、OC2H5)在近热能条件下的气相离子分子反应。PhCHO、PhCOCH3 和 PhCOOCH3 的主要生成途径是亲电加成到 O 原子,产生初始加成离子,占总生成离子的 80.3-95.0%。虽然在 PhCOC2H5 和 PhCOOC2H5 中没有观察到初始加成离子,但通过亲电加成到 O 原子,然后解离和分子消除,形成了主要的产物离子。根据产物离子的分布以及对中间产物和产物能量的半经验计算,对反应机理进行了讨论。所获得的结果与已报道的脂肪族羰基化合物的离子-环共振数据进行了比较。