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本文研究了自由基加成定位效应理论。提出了如下预示自由基加成方向的经验公式: A_f=sum from i=1 to 2(IR+H_c+nd)i R=sum from y=1 to n ry 式中I为诱导效应指数、R为原子或原子团的折射度;H_c定义为甲基(或者烷基)的超共轭效应(或醛,酮羰基以及氰基的共轭效应)因子;nd代表某些和重键直接连结能降低中间自由基能量的原子(或原子团)的d_ 空轨道主量子数;ry为原子团中某一化学键的折射指数;Af定义为自由基加成定位效应指数。 运用经验公式,可以发现,在自由基加成或不对称烯烃单体的自由基聚合反应中,任一自由基(包括大分子链自由基)总是进攻碳一破重键上A_f值较小的不饱和碳原子,或该碳被进攻占优势。两端A_f值差距愈大,则定向的专一性愈强,两端 A_f值相近,则自由基沿两个位置进行加成的几率可能相等。 本公式只适于重键上不连结芳基的不饱和烃。
This paper studies the theory of free radical addition localization effect. The following empirical formulas for predicting the radical addition direction are proposed: A_f = sum from i = 1 to 2 (IR + H_c + nd) i R = sum from y = 1 to n ry where I is the induction effect index, R is Hc is defined as the hyperconjugation effect of methyl (or alkyl) (or the conjugate effect of aldehyde, keto carbonyl and cyano) factor; nd means that some of the direct bonds to the heavy bond can reduce the middle Radical energy of the atom (or atomic group) d_ empty orbit main quantum number; ry is the refractive index of a chemical bond in the atomic group; Af is defined as the radical addition positioning effect index. Using the empirical formula, it can be found that in the free radical polymerization of free radical addition or asymmetric olefin monomer, any free radical (including macromolecular chain free radicals) always attack the carbon-broken A_f value is small Of the unsaturated carbon atoms, or the carbon is offensive predominance. The greater the difference between the A_f values at both ends, the stronger the specificity of the orientation and the closer the A_f values at both ends are, the more the probability of addition of radicals along two positions may be equal. This formula is only suitable for non-bonded aromatic hydrocarbons on the key.