ca.±13%. Assumed activation energies for the reverse reactions yield Si—H bond dissociation enthalpies, D298, of 388 ± 5 and 392 ± 5 kJ mol–1 in methylsilane and dimethylsilane, respectively. These values and the Arrhenius parameters are intermediate between earlier results for Br + SiH4 and Br +(CH3)3SiH, although the uncertainty in D298 is too great to establish a firm trend in D298 with the degree
Br [4p(2 P J)]与CH 3 SiH 3(1)和(CH 3)2 SiH 2(2)的反应动力学已使用快速光解/时间分辨原子共振光谱在整个温度下进行了测量。范围分别为350–550和390–550K。结果为k 1 =(4.0±0.5)×10 –10 exp(–19.7±0.5 kJ mol –1 / RT)和k 2 =(4.3±0.8)×10 –10 exp(–21.6±0.7 kJ mol – 1 / RT)以cm 3 s –1为单位,置信限为。±13%。假定逆反应的活化能在甲基
硅烷和二甲基
硅烷中分别产生388±5和392±5 kJ mol –1的Si-H键解离焓D 298。这些值和阿仑尼乌斯参数是BR +的SiH先前的结果之间的中间4和Br +(CH 3)3的SiH,尽管在不确定性d 298太大以建立牢固的趋势d 298与甲基化程度。
硅烷和相应的甲
硅烷基自由基通过从头开始的方法表征为最高MP4