Rapid Benzylation of Cellulose in Tetra-n-butylphosphonium Hydroxide Aqueous Solution at Room Temperature
Rapid Benzylation of Cellulose in Tetra-n-butylphosphonium Hydroxide Aqueous Solution at Room Temperature
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DOI：
10.1021/acssuschemeng.7b00492
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发表时间：
2017-06-01
影响因子：
8.4
通讯作者：
Nishio, Yoshiyuki
中科院分区：
文献类型：
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作者：
Abe, Mitsuru;Sugimura, Kazuki;Nishio, Yoshiyuki
我们发现纤维素在氢氧化四烷基鎓溶剂系统（47% 氢氧化四正丁基鏻水溶液）中非常快速地发生苄基化。使用与脱水葡萄糖单元类似的9摩尔当量的苄基溴，在环境温度（20-25℃）下10分钟内获得取代度（DS）高于2.5的苄基纤维素（BC）。高效的苄基化反应在反应体系的瞬时稳定乳液状态下进行，产物在液体介质中以固体沉淀物的形式沉淀出来。在20℃下，2分钟后苄基DS为1.92，5分钟和10分钟后分别达到2.40和2.53。在探索的 10-50 摄氏度范围内，反应温度与最大 DS 呈负相关。对于高度取代的 BC（DS > 2.5），没有观察到纤维素主链的显着降解。还针对具有不同 DS 的产品检查了 BC 在常见有机溶剂中的溶解度。
We found a very fast benzylation of cellulose in a tetraalkylonium hydroxide solvent system, 47% tetra-n-butylphosphonium hydroxide aqueous solution. Benzyl cellulose (BC) with a degree of substitution (DS) above 2.5 was obtained within 10 min at ambient temperature (20-25 degrees C) using similar to 9 mol equiv of benzyl bromide to the anhydroglucose unit. The highly efficient benzylation proceeded in the transiently stabilized emulsion state of the reaction system, and the product precipitated out as a solid sediment in the liquid medium. At 20 degrees C, the benzyl DS was 1.92 after 2 min, and reached 2.40 and 2.53 after 5 and 10 min, respectively. The reaction temperature had a negative correlation with the maximum DS in the explored range of 10-50 degrees C. No significant degradation of the cellulosic main chain was observed for highly substituted BCs (DS > 2.5). The solubility of BC in common organic solvents was also examined for products with various DSs.