硅（磷）中心自由基与2─丁烯二酸二乙酯的加合反应机理

STUDING ON MECHANISM OF ADDITION REACTIONS OF Si－OR P－CENTERED RADICALS TO DIETHYL 2－BUTENEDIOATE

用ＥＳＲ方法研究了硅（磷）中心自由基与２－丁烯二酸二乙酯的加合反应机理．具有顺式构型的马来酸二乙酯（ＤＥＭ）与硅（磷）中心自由基反应，生成自由基加合物。ＤＥＭ的聚合反应受到抑制。具有反式构型的富马酸二乙酯（ＤＥＦ）易发生聚合反应，ＤＥＦ与硅（磷）中心自由基的加合反应受到抑制．ＤＥＦ与ＤＥＭ在反应性能上的差异，主要来自ＤＥＦ有较大的空间位阻效应．

The mechanism of the addition reactions Si－or P－centered radicals todiethyl 2－butenedioate has been studied by ESR method．Si－or P－centered radicals couldbe added to diethyl maleate which possesses cis－configuration．Hypertine splitting con-stants of the silyl radical adducts linked with different substituents were measured inour experiments. Radical polymerization of diethyl fumarate which possessestrans－configuration was initiated by radical Bu^tO· and produeed telomer orpolymer. The addition reactions of Si－or P－centered radicals to diethyl fumaratecould not happen due to steric hindranee．