SusCHEM: Mixtures of Ionic Liquids with Compressible Fluids for Biopolymer Separations and Processing of Lignocellulosic Materials

提出的研究项目将探索一种分离木质纤维素材料或木质生物质生物聚合物的新方法。成功的结果预计将导致纯化的纤维素和半纤维素馏分，不含提取物和木质素；或者是不含碳水化合物的纯化木质素。生产不含萃取物和木质素的均匀纤维素资源的可能性具有很高的技术意义。这种资源将大大提高生物乙醇等生物燃料的效率和可持续生产；也可以用作造纸的高级纤维来源，或用于生产纤维素气凝胶或支架。产生统一木质素资源的可能性也具有重要意义。如果可以利用，这种资源可以转化为非石油基、类碳氢化合物的运输燃料，或者转化为先进的材料，如碳纤维或多孔吸附剂。作为溶剂介质，该项目将探索选定的离子液体与超临界或可压缩流体（如二氧化碳和有机溶剂）的混合物。这种方法是非传统的，因为重点将放在使用离子液体上，而不是作为混合物的主要成分，而是作为次要成分。目标是将离子液体的功能或溶剂化能力结合到有机溶剂与更可压缩的超临界流体的混合物中，使其达到足以分离和处理生物聚合物的水平。该方法将可压缩流体的压力可调性与离子液体的溶剂化能力结合起来，同时降低介质的粘度，使其易于加工。目标是开发溶剂-抗溶剂组合，可以通过调节压力和/或温度来选择性溶解和沉淀目标聚合物，同时促进所使用离子液体的回收和再循环。为了实现这些目标，该项目将生成有关选定离子液体与可压缩流体及其与感兴趣的生物聚合物的混合物的高压混相、体积特性、溶解度参数和粘度的基本数据，这些数据是流体成分、压力和温度的函数。在高压下，离子液体与可压缩或超临界流体混合物的拟议组合有望在压力、温度或组分调整方面提供新的工艺灵活性(a)混溶和相分离的热力学条件，或(b)粘度等输运性质，或(c)与化学反应性和转化有关的动力学，或(d)热物理转变和形态修饰。

1509390KiranVA Polytechnic InstThe proposed research program will explore a novel approach for separation of the biopolymers of lignocellulosic materials or woody biomass. The successful outcomes are expected to lead to purified cellulose and hemicellulose fractions that are free of extractives and lignin; or to purified lignin fractions that are free of carbohydrates. The possibility of generating uniform cellulose resources that are free of extractives and lignin is of high technological significance. Such a resource would greatly improve the efficiency and the sustainable production of biofuels such as bioethanol; or may be used as advanced fiber source for paper manufacture, or for production of cellulosic aerogels or scaffolds. The possibility of generating a uniform lignin resource is also of high significance. If it were available, such a resource could be used for possible conversion to nonpetroleum-based, hydrocarbon-like transportation fuels, or for conversion to advanced materials such a carbon fibers or porous adsorbents. As solvent media, the project will explore mixtures of selected ionic liquids with a supercritical or compressible fluid such as carbon dioxide plus an organic solvent. The approach is non-traditional in that the focus will be on using the ionic liquids not as the major, but as a minor component of the mixtures. The objective is to incorporate the functionality or solvating power of the ionic liquids to mixtures of an organic solvent with a more compressible supercritical fluid at a level that would be just sufficient for separation and processing of biopolymers. The methodology is to combine the pressure-tunability of compressible fluids with the solvating power of ionic liquids while at the same time lowering the viscosity of the medium for easier processability. The goal is to develop solvent-antisolvent combinations that can be tuned for selective dissolution and precipitation of target polymers with manipulations of pressure and /or temperature, while at the same time facilitating the recovery and the recycle of the ionic liquids employed. Towards these objectives, the project will generate fundamental data on the high-pressure miscibility, volumetric properties, solubility parameters and viscosity of mixtures of selected ionic liquids with compressible fluids and their mixtures with the biopolymers of interest as a function of the fluid composition, pressure and temperature. The proposed combination of ionic liquids with compressible or supercritical fluid mixtures at high pressures are expected to provide new process flexibilities in terms of pressure, temperature, or compositional tuning of (a) the thermodynamic conditions for miscibility and phase separation, or (b) the transport properties such as viscosity, or (c) the kinetics with respect to either chemical reactivity and transformations, or (d) the thermophysical transitions and morphological modifications.