= 4.18 J) and this leads to D[H—CH(C2H3)2]= 76.4 kcal mol–1, which by comparison with the value of 95.0 for the secondary C—H bond dissociation energy in alkanes leads to a figure of 18.6 ± 1.5 kcal mol–1 for the resonance stabilisation energy of the pentadienyl radical.
通过测量在653–716 K范围内的温度和15至200 Torr的压力下3-甲基戊-1、4-二烯热解过程中
甲烷的初始形成速率,已证明
甲烷是由均相形成的,一阶过程。对其他热解产物的检查表明,形成伯
甲烷的最合理方式是[省略图示],然后是[省略图示]。反应(i)的速率表达式为log(k i / s –1)=(15.36±0.1)–(65040±300)/ θ,其中θ = 2.303 R T / cal mol –1(1 cal = 4.18 J)这导致D [H-CH(C 2 H 3)2 ] = 76.4 kcal mol –1,与
烷烃中二级CH键离解能的95.0相比,
戊二烯基的共振稳定能为18.6±1.5 kcal mol –1。