Magalhães Solange, Moreira Adriana, Almeida Ricardo, Cruz Pedro Fernandes, Alves Luís, Costa Carolina, Mendes Cátia, Medronho Bruno, Romano Anabela, Carvalho Maria da Graça, Gamelas José A F, Rasteiro Maria da Graça
CIEPQPF, Department of Chemical Engineering, University of Coimbra, Pólo II - R. Silvio Lima, 3030-790 Coimbra, Portugal.
CQC, Department of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal.
ACS Omega. 2022 Jul 19;7(30):26005-26014. doi: 10.1021/acsomega.1c07380. eCollection 2022 Aug 2.
The selective extraction and recovery of different lignocellulosic molecules of interest from forestry residues is increasing every day not only to satisfy the needs of driving a society toward more sustainable approaches and materials (rethinking waste as a valuable resource) but also because lignocellulosic molecules have several applications. For this purpose, the development of new sustainable and ecologically benign extraction approaches has grown significantly. Deep eutectic solvents (DESs) appear as a promising alternative for the processing and manipulation of biomass. In the present study, a DES formed using choline chloride and levulinic acid (ChCl:LA) was studied to fractionate lignocellulosic residues of acacia wood ( Link), an invasive species in Portugal. Different parameters, such as temperature and extraction time, were optimized to enhance the yield and purity of recovered cellulose and lignin fractions. DESs containing LA were found to be promising solvent systems, as the hydrogen bond donor was considered relevant in relation to lignin extraction and cellulose concentration. On the other hand, the increase in temperature and extraction time increases the amount of extracted material from biomass but affects the purity of lignin. The most promising DES system, ChCl:LA in a ratio of 1:3, was found to not significantly depolymerize the extracted lignin, which presented a similar molecular weight to a kraft lignin. Additionally, the P NMR results revealed that the extracted lignin has a high content of phenolic OH groups, which favor its reactivity. A mixture of ChCl:LA may be considered a fully renewable solvent, and the formed DES presents good potential to fractionate wood residues.
从林业残余物中选择性提取和回收不同的木质纤维素目标分子的情况日益增多，这不仅是为了满足推动社会走向更可持续的方法和材料（将废物重新视为宝贵资源）的需求，还因为木质纤维素分子有多种应用。为此，新型可持续且生态友好的提取方法得到了显著发展。深共熔溶剂（DESs）似乎是一种处理和操控生物质的有前景的替代物。在本研究中，对一种由氯化胆碱和乙酰丙酸形成的DES（ChCl:LA）进行了研究，以分离葡萄牙的一种入侵物种——阿拉伯胶树（Link）的木质纤维素残余物。对诸如温度和提取时间等不同参数进行了优化，以提高回收的纤维素和木质素馏分的产率和纯度。发现含LA的DESs是有前景的溶剂体系，因为氢键供体被认为与木质素提取和纤维素浓缩相关。另一方面，温度和提取时间的增加会提高从生物质中提取的物质的量，但会影响木质素的纯度。最有前景的DES体系，即比例为1:3的ChCl:LA，被发现不会使提取的木质素显著解聚，其分子量与硫酸盐木质素相似。此外，P NMR结果表明提取的木质素含有高含量的酚羟基，这有利于其反应活性。ChCl:LA的混合物可被视为完全可再生溶剂，所形成的DES在分离木材残余物方面具有良好潜力。
