Fractional Precipitation of Softwood Kraft Lignin: Isolation of Narrow Fractions Common to a Variety of Lignins
Fractional Precipitation of Softwood Kraft Lignin: Isolation of Narrow Fractions Common to a Variety of Lignins
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DOI：
10.1021/sc400545d
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发表时间：
2014-04-01
影响因子：
8.4
通讯作者：
Argyropoulos, Dimitris S.
中科院分区：
文献类型：
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作者：
Cui, Chengzhong;Sun, Runkun;Argyropoulos, Dimitris S.
以类似于原油的方式，如果要实现工业木质素作为明确分子量聚合物和低聚物的反应性多酚的潜力，则工业木质素需要精炼。在本文中，我们证明了一个连续的窄馏分可以被隔离的非极性溶剂（己烷）的极性（丙酮）溶液中的软木木材硫酸盐木质素的增量添加。三个不同的软木硫酸盐木质素的商业样品被用来检查的有效性开发的协议，使用详细的色谱和定量官能团分析方法。结果表明，所有样品都含有一种常见的相对单分散的多酚材料部分，其可以从不同的木质素中分离出来，产率范围在10和20%w/w之间。开发的分级沉淀协议的多功能性进一步验证，通过创建人工物理混合物的检查木质素在不同的比例，并从中分离精确计算的馏分几乎相同的分子量分布和组成。总之，这里描述的分级沉淀方法提供了一种可能性，即可以分离出各种软木硫酸盐木质素所共有的代表性特定窄级分，而不管制浆工艺的制造细节如何。因此，由于制造纸浆中的制造变化，其组成相对不可预测的另外已知的非均质硫酸盐木质素材料现在可以提供具有显著商业衍生物的一致均质木质素流。
In a manner similar to crude oil, technical lignins need refining if their potential as reactive polyphenols of well-defined molecular weight polymers and oligomers is to be actualized. In this paper, we demonstrate that a continuum of narrow fractions can be isolated by the incremental addition of a nonpolar solvent (hexanes) in a polar (acetone) solution of softwood wood kraft lignin. Three distinct commercial samples of softwood kraft lignin were used to examine the validity of the developed protocol using detailed chromatographic and quantitative functional group analytical methods. It was shown that all samples contain a common relatively monodisperse fraction of a polyphenolic material that can be isolated from the different lignins in yields ranging between 10 and 20% w/w. The versatility of the developed fractional precipitation protocol was further validated by creating artificial physical mixtures of the examined lignins in different proportions and isolating from them precisely calculated fractions of nearly identical molecular weight distributions and composition. Overall, the fractional precipitation approach described here offers the possibility that representative specific narrow fractions, common to a variety of softwood kraft lignins, can be isolated irrespective of the manufacturing details of the pulping process. As such, the otherwise known heterogeneous kraft lignin material, whose composition is relatively unpredictable due to manufacturing variations in making pulp, may now offer consistently homogeneous lignin streams with significant commercial ramifications.