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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Addition Reactions of Alkyl and Carboxyl Radicals to Vinylidene Fluoride
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Addition Reactions of Alkyl and Carboxyl Radicals to Vinylidene Fluoride

机译：烷基和羧基自由基与偏二氟乙烯的加成反应

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摘要

The addition reactions of alkyl radicals CF3·and CH3·and carboxyl radicals C2H5O·,C2H5OCOO·,CF3COO·,and CH3COO·to a vinylidene fluoride(VDF)molecule are studied using ab initio calculations.These radicals were selected because they are intermediate or final products of diacyl peroxides decomposition in the initiation reactions of VDF polymerization.Two combinations of methods for energetics and structure optimization are applied:QCISD/6-311G(d,p)//HF/6-31G(d)and B3LYP/6-31 lG+(3df,2p)//B3LYP/6-31G(d).It is found that the formed bond length of the product,the forming bond length of the transition state,and the attack angle of the product structures are not sensitive to the level of theory even though the attack angle of the transition state structures is.Early transition states are obtained upon attack at both high-substituted and nonsubstituted carbon atom VDF ends.Kinetic and thermodynamic control rules play different roles on governing the reactivity of the addition with the studied radicals.Both theoretical methods yield the same trends for the preferential attack site in terms of regioselectivity,barrier energies,and reaction enthalpies.It is shown that the addition reactions of the intermediate radicals C2H5OCOO·,CF3COO·,and CH3COO· of the decomposition of diethyl peroxydicarbonate,trifluoroacetyl peroxide,and diacetyl peroxide initiators yield smaller energy barriers than the additions of the corresponding final radicals,C2H5O·,CF3·,and CH3·;therefore,the reactions of the intermediate radicals should not be ignored when analyzing the initiation process of the VDF polymerization using those initiators.
机译：利用从头算的方法研究了烷基CF3·和CH3·以及羧基C2H5O·，C2H5OCOO·，CF3COO·和CH3COO·与亚乙烯基氟化物（VDF）分子的加成反应。 VDF聚合引发反应中二酰基过氧化物的最终产物分解。应用了能量学和结构优化方法的两种组合：QCISD / 6-311G（d，p）// HF / 6-31G（d）和B3LYP / 6 -31 lG +（3df，2p）// B3LYP / 6-31G（d）。发现产物的形成键长，过渡态的形成键长和产物结构的攻角不大即使过渡态结构的迎角是理论值，它也是敏感的。在高取代和未取代的碳原子VDF末端发生攻击时，都会获得早期的过渡态。动力学和热力学控制规则在控制反应性方面起着不同的作用。与研究相加在区域选择性，势垒能和反应焓方面，两种理论方法对于优先攻击位点都具有相同的趋势。结果表明，中间自由基C2H5OCOO·，CF3COO·和CH3COO·的加成反应会分解过氧二碳酸二乙酯，三氟乙酰基过氧化物和二乙酰基过氧化物引发剂的能垒比相应的最终自由基C2H5O·，CF3·和CH3·的加入要小;因此，分析引发过程时不应忽略中间自由基的反应使用那些引发剂的VDF聚合反应。

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