Absolute Rate Constants for Radical Additions to Alkenes in Solution. The Synergistic Effect of Perfluorination on the Reactivities of <i>n</i>-Alkyl Radicals<sup>1</sup>
作者:David V. Avila、K. U. Ingold、J. Lusztyk、W. R. Dolbier、H.-Q. Pan
DOI:10.1021/jo951782v
日期:1996.1.1
determine the absolute rate constants for addition of several partially fluorinated n-alkyl radicals to three styrenes at 25 °C in Freon 113. Fluorination at the γ-position (RCF2CH2CH2•) gives radicals with essentially the same reactivity as non-fluorinated n-alkyls. The RCH2CF2CH2• and RCH2CH2CHF• radicals are both about three times as reactive as RCF2CH2CH2•, but the RCH2CH2CF2• radical is ca. five to six
在25°C的氟利昂113中,已经使用激光闪光光解法确定了将几个部分氟化的n-烷基自由基加到三个苯乙烯中的绝对速率常数。在γ位置的氟化(RCF2CH2CH2•)产生的自由基具有基本相同的反应性作为非氟化的正烷基。RCH2CF2CH2•和RCH2CH2CHF•自由基的活性均约为RCF2CH2CH2•的三倍,但RCH2CH2CF2•的自由基约为ca。五到六次而不是大约 是RCH2CH2CHF•的三倍。类似地,全氟自由基CF3CF2CF2•的反应性比基于RCH2CF2CH2•和RCH2CH2CF2•的反应性所预期的要高得多。因此,全氟化的正烷基比根据α-,β-和γ-氟化作用的单独作用所预测的反应性要高得多。