Bisorthoesters as polymer intermediates. II. A facile method for the preparation of polybenzimidazoles
Bisorthoesters as polymer intermediates. II. A facile method for the preparation of polybenzimidazoles
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双乙酰酯作为聚合物中间体。
DOI：
10.1002/pol.1978.170160806
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发表时间：
1978
期刊：
影响因子：
--
通讯作者：
O. Vogl
中科院分区：
文献类型：
--
作者：
C. Dudgeon;O. Vogl
芳香族双酰酯是良好的聚合物中间体，可以在温和条件下，在 DMSO 中，在 100°C 下，在相对较短的反应时间内与芳香族四胺缩合，得到聚苯并咪唑。对苯二甲酸和间苯二甲酸的六丙基原酸酯是优选的芳族原酸酯，因为它们是液体，因此通过真空蒸馏相对容易地纯化为聚合物级中间体。即使在接近或高于原酸酯基团分解温度的良好真空下，高级原酸酯也会蒸馏。还使用了原草酸六乙酯，它是一种非常有用且稳定的草酸衍生物，可用于缩合反应。这三种原酸酯用于与3,3',4,4'-四氨基联苯、1,2,3,4-四氨基苯、3,3',4,4'-四氨基联苯醚和3,3',4,4'-四氨基二苯甲酮缩合。所有聚苯并咪唑均以高定量产率获得，并且具有不同的分子量（ηinh = 0.1−0.8 dl/g），在某些情况下处于纤维形成范围内。
Aromatic bisorthoesters were found to be good polymer intermediates and could be condensed with aromatic tetramines under mild conditions, in DMSO at 100°C in a relatively short reaction time to give polybenzimidazoles. The hexapropyl orthoesters of terephthalic and isophthalic acid were the preferred aromatic orthoesters because they were relatively easily purified by vacuum distillation to polymer grade intermediates, since they are liquids. Higher orthoesters distill even under good vacuum near or above the decomposition temperature of the orthoester group. Hexaethyl orthooxalate was also used and is a very useful and stable derivative of oxalic acid, which can be used for condensation reactions. These three orthoesters were used for condensations with 3,3′,4,4′-tetraaminobiphenyl, 1,2,3,4-tetraaminobenzene, 3,3′,4,4′-tetraaminobiphenyl ether, and 3,3′,4,4′-tetraaminobenzophenone. All polybenzimidazoles were obtained in high to quantitative yields and with varying molecular weights (ηinh = 0.1−0.8 dl/g), which in some cases were in the fiber forming range.