Xie Xinyi, Li Lifeng, Wang Xiangyu, Liu Qiyu, Ouyang Xinping, Qiu Xueqing
School of Chemistry & Chemical Engineering, South China University of Technology, Guangzhou 510640, China.
Guangdong University of Technology, Guangzhou 510006, China.
J Agric Food Chem. 2025 Feb 5;73(5):2880-2889. doi: 10.1021/acs.jafc.4c12533. Epub 2025 Jan 23.
Effective fractionation of lignocellulose into hemicellulose, cellulose, and lignin is the precondition for full-component valorization. Generally, harsh reaction conditions are used to improve fractionation efficiency, which leads to severe lignin condensation and inhibits its value-added applications. To address this issue, a novel biphasic system consisting of molten salt hydrates (MSHs) and n-butanol was developed for birch fractionation. After the removal of hemicellulose in dilute acid, the solid residue composed of cellulose and lignin was carried out in biphasic system conversion. Cellulose was selectively converted into 73.3% yield of glucan oligomers and 16.8% glucose in the MSH phase, while lignin was in situ-extracted into the -butanol phase with a high yield of 98.1%. Mechanism studies revealed that the in situ extraction together with C-OH group modification by n-butanol synchronously protected lignin β-O-4 linkages from cleavage, resulting in a high β-O-4 content of 53.7%, indicating that 87.7% of β-O-4 linkages in birch has been preserved. After depolymerization, a promising monophenol yield of 22.4% was obtained, which was 81.5% of the theoretical maximum monophenol yield obtained from birch. This fractionation strategy can also be used in softwood and herbaceous, showing a splendid separation efficiency as well as a high yield of noncondensed lignin production.
将木质纤维素有效分离为半纤维素、纤维素和木质素是全组分高值化利用的前提条件。一般来说，需要采用苛刻的反应条件来提高分离效率，这会导致严重的木质素缩合，并抑制其增值应用。为了解决这个问题，开发了一种由熔盐水合物（MSHs）和正丁醇组成的新型双相体系用于桦木的分离。在稀酸中去除半纤维素后，将由纤维素和木质素组成的固体残余物在双相体系中进行转化。纤维素在MSH相中选择性地转化为葡聚糖低聚物，产率为73.3%，葡萄糖产率为16.8%，而木质素则原位萃取到正丁醇相中，产率高达98.1%。机理研究表明，原位萃取以及正丁醇对C-OH基团的修饰同步保护了木质素的β-O-4键不被断裂，使得β-O-4含量高达53.7%，这表明桦木中87.7%的β-O-4键得以保留。解聚后，获得了有前景的22.4%的单酚产率，这是从桦木中获得的理论最大单酚产率的81.5%。这种分离策略也可用于针叶木和草本植物，显示出出色的分离效率以及高产量的非缩合木质素。
