Thermal Decomposition Mechanisms of <i>tert</i>-Alkyl Peroxypivalates Studied by the Nitroxide Radical Trapping Technique
作者:Tomoyuki Nakamura、W. Ken Busfield、Ian D. Jenkins、Ezio Rizzardo、San H. Thang、Shuji Suyama
DOI:10.1021/jo990680s
日期:2000.1.1
mechanism involving concerted two-bond scission within the solvent cage to generate the tert-butyl radical, CO(2), and an alkoxyl radical. The thermolysis rate constants of tert-alkyl peroxypivalates 1 were influenced by both inductive and steric effects [Taft-Ingold equation, log(rel k(d)) = (0.97 +/- 0. 14)Sigmasigma - (0.31 +/- 0.04)SigmaE(s)(c), was obtained].
通过使用氮氧化物自由基捕获技术,研究了一系列枯烯中的叔烷基过氧新戊酸酯1的热解。由热分解产生的叔烷氧基经历了单分子反应,β断裂和1,5-H移位,与从枯烯中提取氢竞争。叔烷氧基自由基β-断裂的绝对速率常数(变化超过4个数量级)表明烷氧基自由基的行为截然不同。但是,自由基产生效率1仅有微小的变化,从53(R = Me)到63%(R = Bu(t)()),支持了一种机制,该机制涉及溶剂笼中的双键双键断裂产生叔叔-丁基,CO(2)和烷氧基。