水合氯化锌的离子液体特性决定了赋予纤维素溶解性的溶剂特性。
Ionic Liquid Character of Zinc Chloride Hydrates Define Solvent Characteristics that Afford the Solubility of Cellulose.
作者信息
Sen Sanghamitra, Losey Bradley P, Gordon Elijah E, Argyropoulos Dimitris S, Martin James D
机构信息
Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
Department of Forest Biomaterials, North Carolina State University , Raleigh, North Carolina 27695-8001, United States.
出版信息
J Phys Chem B. 2016 Feb 18;120(6):1134-41. doi: 10.1021/acs.jpcb.5b11400. Epub 2016 Feb 3.
The recently described ionic liquid structure of the three equivalent hydrate of zinc chloride (ZnCl2·R H2O, R = 3, existing as [Zn(OH2)6][ZnCl4]) explains the solubility of cellulose in this medium. Only hydrate compositions in the narrow range of 3 - x < R < 3 + x with x ≈ 1 dissolve cellulose. Once dissolved, the cellulose remains in solution up to the R = 9 hydrate. Neutron diffraction and differential pair distribution function analysis of cellulose and model compound solutions (1 wt % cellulose in the R = 3 hydrate and 1 wt % ethanol in the R = 3 hydrate and the ZnCl2·3 ethanol liquid) coupled with detailed solubility measurements suggest that cellulose solubility occurs via coordination of the primary OH to the hydrated zinc cation with ring hydroxyls forming part of a second coordination shell around the cation of the ionic liquid.
最近描述的氯化锌三水合物（ZnCl₂·R H₂O，R = 3，以[Zn(OH₂)₆][ZnCl₄]形式存在）的离子液体结构解释了纤维素在该介质中的溶解性。只有在3 - x < R < 3 + x（x ≈ 1）的狭窄范围内的水合物组成才能溶解纤维素。一旦溶解，纤维素在R = 9水合物之前都能保持在溶液中。对纤维素和模型化合物溶液（R = 3水合物中的1 wt%纤维素、R = 3水合物中的1 wt%乙醇以及ZnCl₂·3乙醇液体）进行中子衍射和差分对分布函数分析，并结合详细的溶解度测量结果表明，纤维素的溶解是通过伯羟基与水合锌阳离子配位实现的，其中环羟基形成了离子液体阳离子周围第二配位层的一部分。
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