Anionic cyclopolymerization of methacrylic anhydride with the aid of bulky aluminum Lewis acid
Anionic cyclopolymerization of methacrylic anhydride with the aid of bulky aluminum Lewis acid
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大体积铝路易斯酸辅助甲基丙烯酸酐的阴离子环聚反应
DOI：
10.1016/j.polymer.2012.12.078
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发表时间：
2013
期刊：
影响因子：
4.6
通讯作者：
Tatsuki Kitayama
中科院分区：
文献类型：
--
作者：
Takehiro Kitaura;Naoko Moroi;Tatsuki Kitayama
通过核磁共振和红外光谱证实，在- 78°C的条件下，锂酯烯酸盐与体积较大的铝双苯氧化合物在二氯甲烷中首次阴离子聚合甲基丙烯酸酐，得到由六元环化单元组成的聚合物，而体积较小的三烷基铝则无效。在较高的温度下，由于铝化合物中的烷基与单体发生羰基加成反应，没有形成聚合产物。从存在铝化合物和不存在铝化合物的模型反应中，提出了形成烯醇酸-铝酸盐型物质的重要性。聚丙烯酸甲酯（MAAn）衍生的聚丙烯酸甲酯（PMMA）与自由基制备的PMMA相比，具有丰富的同时性。
Methacrylic anhydride was anionically polymerized for the first time by a lithium ester enolate with the aid of the bulky aluminum bisphenoxides in dichloromethane at −78 °C to afford polymers consisting of six-membered cyclized units as confirmed by NMR and IR spectroscopy, while a less bulky trialkylaluminum was ineffective. At higher temperatures, no polymeric product formed partly due to the carbonyl addition reaction of the alkyl group in the aluminum compound to the monomer. From the model reactions in the presence and absence of the aluminum compounds, importance of formation of an enolate–aluminate type species is suggested. Tacticity of PMMA derived from poly(MAAn) is rich in syndiotacticity in comparison to radically prepared one.