Institute of Chemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Street, Cau Giay, Ha Noi City, Viet Nam; Hanoi University of Science (HUS), Vietnam National University (VNU), 334 Nguyen Trai, Hanoi, Viet Nam.
Institute of Chemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Street, Cau Giay, Ha Noi City, Viet Nam; Hanoi University of Science and Technology (HUST), 01 Dai Co Viet Road, Ha Noi City, Viet Nam.
Chemosphere. 2021 Feb;265:129062. doi: 10.1016/j.chemosphere.2020.129062. Epub 2020 Nov 23.
The modified Al-MCM-41 solid acids with turning Si/Al molar ratio were successfully fabricated through a hydrothermal route and utilized as a suitable catalyst in the cellulose conversion into 5-hydroxylmethylfurfural (5-HMF). The crystal structure, composition, morphologies and porosity of as-synthesized acids were characterized by XRD, FT-IR, N adsorption-desorption, TEM and EDS. The Al MAS NMR and Si-MAS NMR results revealed the existence of both Al framework and Al extra framework. Besides, the existence of medium-weak and strong acid sites, according to Brønsted and Lewis acidity, in Al-MCM-41 acids was confirmed by NH-TPD and FTIR-pyridine adsorption. The 30Al-MCM-41 solid acid (Si/Al molar ratio = 30) exhibited excellent activity with the highest 5-HMF yield of 40.56% compared to other samples. We also discovered that 5-HMF production, as well as cellulose conversion, strongly depended on the total acid, strong/medium-weak acid ratio, as well as Brønsted/Lewis acid ratio. Therefore, these parameters have been considered as essential factors for the design of solid acid for 5-HMF production.
通过水热路线成功制备了具有可调硅铝摩尔比的改性 Al-MCM-41 固体酸，并将其用作纤维素转化为 5-羟甲基糠醛（5-HMF）的合适催化剂。通过 XRD、FT-IR、N2 吸附-解吸、TEM 和 EDS 对合成酸的晶体结构、组成、形态和孔隙率进行了表征。Al MAS NMR 和 Si-MAS NMR 结果表明存在 Al 骨架和 Al 骨架外。此外，根据 Brønsted 和 Lewis 酸度，通过 NH-TPD 和 FTIR-吡啶吸附证实了 Al-MCM-41 酸中存在中强酸和强酸位。与其他样品相比，30Al-MCM-41 固体酸（Si/Al 摩尔比=30）表现出优异的活性，5-HMF 的最高收率为 40.56%。我们还发现，5-HMF 的产量以及纤维素的转化率强烈依赖于总酸、强酸/中强酸比以及 Brønsted/Lewis 酸比。因此，这些参数被认为是设计用于 5-HMF 生产的固体酸的重要因素。
