Separation of ethanol–water mixtures by liquid–liquid extraction using phosphonium-based ionic liquids
Separation of ethanol–water mixtures by liquid–liquid extraction using phosphonium-based ionic liquids
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DOI：
10.1039/c1gc15079k
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发表时间：
2011-06
期刊：
影响因子：
9.8
通讯作者：
C. S. Neves;J. Granjo;M. Freire;A. Robertson;N. Oliveira;J. Coutinho
中科院分区：
文献类型：
--
作者：
C. S. Neves;J. Granjo;M. Freire;A. Robertson;N. Oliveira;J. Coutinho
生物醇是通过发酵从生物质中产生的，蒸馏通常用于从水相中分离醇。然而，这是一个高能耗的过程，正在寻求这种分离的替代方法。本文研究了利用磷基离子液体（ILs）从发酵液中提取乙醇。确定了7种离子液体的三元相图，这是设计和实施一种可替代的液-液萃取工艺以回收酒精所必需的。利用cosmos - rs和NRTL模型对平衡数据进行建模；前者旨在筛选其他没有实验研究的离子液体，后者旨在设计一种分离过程。所收集的数据表明，磷基离子液体是迄今为止报道的最好的水-乙醇分离材料。基于最有希望的相图，对酒精和离子液体的回收步骤进行了分析，并提出了与萃取发酵相结合的液-液萃取阶段，其中离子液体不断循环到发酵罐，乙醇浓度通过渗透蒸发进行，作为蒸馏的替代方案。
Bio-alcohols are produced from biomass by fermentation, and distillation is commonly used to separate the alcohol from the aqueous phase. This is, however, a high energy consumption process, and alternative approaches to this separation are being pursued. In this work, the use of phosphonium-based ionic liquids (ILs) for the extraction of ethanol from fermentation broths is investigated. Ternary phase diagrams, necessary for the design and to implement an alternative liquid–liquid extraction process for the alcohol recovery, were determined for seven ionic liquids. The modelling of the equilibrium data was performed using the COSMO-RS and NRTL models; the first aiming at screening other ionic liquids not experimentally studied, and the latter aiming at designing a separation process. The gathered data indicate that phosphonium-based ionic liquids are the best yet reported to perform water–ethanol separations. Based on the most promising phase diagrams, an analysis of the alcohol and ionic liquid recovery steps was carried out and a liquid–liquid extraction stage coupled to an extractive fermentation, where the ionic liquid is continuously recycled to the fermentator and the ethanol concentration is carried out by pervaporation, is here proposed as an alternative to distillation.