Faculty of Chemistry and Pharmacy, University of Innsbruck, 6020 Innsbruck, Austria.
Biomacromolecules. 2012 Jun 11;13(6):1973-80. doi: 10.1021/bm300582s. Epub 2012 May 25.
Herein we describe a possibility of selective dissolution of xylan, the most important type of hemicellulose, from Eucalyptus globulus kraft pulp using ionic liquids (ILs). On the basis of the IL 1-butyl-3-methylimidazolium dimethyl phosphate, which is well-known to dissolve pulp, the phosphate anion was modified by substituting one oxygen atom for sulfur and selenium, respectively. This alteration reduces the hydrogen bond basicity of the IL and therefore prevents dissolution of cellulose fibers, whereas the less ordered xylan is still dissolved. (1)H NMR spectra of model solutions and Kamlet-Taft parameters were used to quantify the solvent polarity and hydrogen bond acceptor properties of the ILs. These parameters have been correlated to their ability to dissolve xylan and cellulose, which was monitored by (13)C NMR spectroscopy. It was found that the selectivity for xylan dissolution increases to a certain extent with decreasing hydrogen-bond-accepting ability of anions of the ILs.
本文描述了一种使用离子液体（ILs）从桉树硫酸盐浆中选择性溶解木聚糖（最重要的半纤维素类型）的可能性。基于众所周知的溶解纸浆的 1-丁基-3-甲基咪唑二甲基磷酸盐，分别用硫和硒取代磷酸阴离子中的一个氧原子。这种改变降低了 IL 的氢键碱性，因此防止了纤维素纤维的溶解，而结构无序的木聚糖仍然被溶解。模型溶液的 1H NMR 光谱和 Kamlet-Taft 参数用于定量 IL 的溶剂极性和氢键接受性能。这些参数与它们溶解木聚糖和纤维素的能力相关联，这通过 13C NMR 光谱监测。结果发现，随着 IL 阴离子氢键接受能力的降低，木聚糖溶解的选择性在一定程度上增加。
