Ground-state CF2 was monitored by kinetic spectroscopy after long wavelength flash photolysis of C2F4+ NO2+ N2 mixtures and was ascribed as a product of the overall reaction O(23P)+ C2F4→ CF2O + CF2. (1) From the decrease in the CF2 yield in competitive systems, rate constants relative to k1 were determined for CF2CFCl and CF2CCl2. The reactivities of the chlorofluoroethylenes show a similar trend with ionization potential to that established for hydrocarbon olefins. From preliminary measurements of the overall decomposition of C2F4 flashed in O2 at 25°C, it is proposed that singlet CF2 reacts with O2 about 0.2 times as rapidly as with C2F4. Although there was no direct evidence for triplet CF2 molecules formed in (1), the results are consistent with an earlier analysis of continuous photolysis experiments, if CF*2 is rapidly relaxed in collisions with NO2 or NO.
在对
C2F4+
NO2+ N2 混合物进行长波长闪光光解后,通过动力学光谱监测了基态
CF2,并将其归结为 O(23P)+ →
CF2O +
CF2 总反应的产物。 (1) 根据竞争体系中
CF2 产率的降低,确定了
CF2CFCl 和
CF2CCl2 相对于 k1 的速率常数。
氯氟乙烯的反应活性随电离电位的变化趋势与碳氢化合物烯烃的变化趋势相似。根据对 25°C 下 在 O2 中闪烁的整体分解的初步测量,
单质 CF2 与 O2 反应的速度约为 的 0.2 倍。虽然没有直接证据表明在(1)中形成了三重
CF2分子,但如果CF*2在与 或NO的碰撞中迅速弛豫,则结果与早先对连续光解实验的分析一致。