Department of Bioproducts and Biosystems, School of Chemical Technology, Aalto University, P.O. Box 16300, 00076 Aalto, Finland.
Carbohydr Polym. 2017 Jul 15;168:121-128. doi: 10.1016/j.carbpol.2017.03.013. Epub 2017 Mar 8.
Hemicellulose lean pulps are a raw material source for numerous high value products. We have previously presented the IONCELL-P(ulp) process, a hemicellulose extraction method, based on a binary mixture of ionic liquid and water. The IONCELL-P process does not suffer from yield losses or polymer degradation and retains the Cellulose I crystalline form. In this paper, a selection of cellulose dissolving ionic liquids is tested, in order to compare their applicability in the process. We demonstrate that the extraction selectivity towards low molar mass polymers is related to the anion's ability to accept hydrogen bonds (Kamlet-Taft β-value), if divided by the water molar fraction of the solvent system. Pulp consistency, solvent system viscosity and pH are investigated in order to identify the factors affecting the extraction efficiency. The results show that all the tested ionic liquid-water mixtures were able to dissolve hemicelluloses, but there were differences in their efficiency, selectivity and the ability to process high pulp consistencies.
半纤维素贫浆是许多高价值产品的原料来源。我们之前提出了 IONCELL-P（浆）工艺，这是一种基于离子液体和水的二元混合物的半纤维素提取方法。IONCELL-P 工艺不会产生收率损失或聚合物降解，并且保留纤维素 I 晶型。在本文中，选择了一系列纤维素溶解离子液体进行测试，以便比较它们在该工艺中的适用性。我们证明，低摩尔质量聚合物的提取选择性与阴离子接受氢键的能力（Kamlet-Taft β 值）有关，如果除以溶剂系统中水的摩尔分数。为了确定影响提取效率的因素，研究了纸浆浓度、溶剂系统粘度和 pH 值。结果表明，所有测试的离子液体-水混合物都能够溶解半纤维素，但它们在效率、选择性和处理高纸浆浓度的能力方面存在差异。
