Anionic polymerization of methyl methacrylate in an ionic liquid
Anionic polymerization of methyl methacrylate in an ionic liquid
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DOI：
10.1002/pat.1210
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发表时间：
2008-10-01
影响因子：
3.4
通讯作者：
Watanabe, Masayoshi
中科院分区：
文献类型：
--
作者：
Kokubo, Hisashi;Watanabe, Masayoshi
以正丁基锂（it-BuLi）和二苯基己基锂（DPHLi）为引发剂，在离子液体中进行了甲基丙烯酸甲酯（MMA）的阴离子聚合反应。在具有双（三氟甲基磺酰基）酰胺（[NTf 2]）阴离子的离子液体中的聚合没有产生聚（MMA）（PMMA），因为引发剂由于对三氟甲基基团的攻击而失活。通过使用1-丁基-3-甲基咪唑鎓六氟磷酸盐（[C（4）mim][PF 6]），进行聚合反应。在[C（4）mim][PF 6]中制备的PMMA产率较低（5-9%），而在四氢呋喃（THF）中制备的PMMA产率为15-62%，且所制备的PMMA具有较大的多分散指数（等于2.0）。所获得的结果可归因于与MMA的常见阴离子聚合温度（-78 ℃）相比的高反应温度（0 ℃）以及引发剂与咪唑鎓阳离子之间的反应。认为引发剂失活，因为咪唑鎓环的2-位上的氢原子被烷基锂引发剂抽出。在[C（4）mim][PF 6]中利用DPHLi制备的PMMA的立构规整度与在甲苯中聚合的类似，富含mm三单元组。版权所有（C）2008约翰威利父子有限公司
Anionic polymerization reactions of methyl methacrylate (MMA) in ionic liquids were carried out by utilizing alkyl lithium initiators such as n-butyl lithium (it-BuLi) and diphenylhexyl lithium (DPHLi). The polymerization in ionic liquids having bis(trifluoromethyl sulfonyl)amide ([NTf2]) anion did not yield poly(MMA) (PMMA), because of the deactivation of the initiator due to an attack on the trifluoromethyl group. By using 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF6]), the polymerization reactions proceeded. The PMMA prepared in [C(4)mim][PF6] gave low yields (5-9%), as compared with those (15-62%) obtained for PMMA prepared in tetrahydrofuran (THF), and the prepared PMMA had large polydispersity indices (congruent to 2.0). The results obtained can be attributed to the high reaction temperature (0 degrees C), in comparison to the common anionic polymerization temperature of MMA, -78 degrees C, and the reaction between the initiator and the imidazolium cation. The initiator was considered to be deactivated because the hydrogen atom at the 2-position of the imidazolium ring was withdrawn by the alkyl lithium initiator. The tacticity of the obtained PMMA, prepared in [C(4)mim][PF6] by utilizing DPHLi, was rich in mm triads, similar to that polymerized in toluene. Copyright (C) 2008 John Wiley & Sons, Ltd.