低共熔溶剂特性及在分离过程中的应用

与传统有机溶剂和离子液体相比,低共熔溶剂具有低熔点、低成本、低毒性、易制备、能再生、可生物降解等优点,为其在分离提纯过程中的应用提供了较大的空间。主要综述了低共熔溶剂的熔点特性,以及在分离酸性气体、醇类、酚类、芳烃等领域的应用。     

低共熔溶剂用于萃取分离的研究进展

作为一种新型的绿色溶剂,低共熔溶剂（DES）拥有与离子液体媲美的优良特性,如挥发性小、可设计性等,且具有成本低廉和制备简单的优势,使得DES正逐步替代传统有机溶剂,在萃取分离应用方面得到广泛的关注。本文综述了近年来国内外有关DES在萃取分离方面的研究报道,阐述了DES直接用于液液萃取、在线生成DES的缔合萃取和通过DES分解完成萃取的应用,并分析比较了各过程的特点和存在的问题;介绍了DES在不同萃取体系中的稳定性和DES的回收方法;总结了DES萃取分离体系的理论发展和萃取机理的研究进展;展望了DES用于萃取分离的工业化前景,指出了目前面临的DES理论、萃取机理、循环稳定性等方面的挑战,分析了进一步的研究趋势。     

低共熔溶剂性质及其应用研究进展

从低共熔溶剂的物理性质出发,综述了近年来低共熔溶剂在生物催化转化、无机材料的合成和电化学等方面的应用,并就低共熔溶剂的应用现状、进展和发展趋势做了相应的评估、论证和建议。     

低共熔溶剂性质及其应用研究进展

从低共熔溶剂的物理性质出发,综述了近年来低共熔溶剂在生物催化转化、无机材料的合成和电化学等方面的应用,并就低共熔溶剂的应用现状、进展和发展趋势做了相应的评估、论证和建议。     

低共熔溶剂及其应用的研究进展

简述了低共熔溶剂的分类、性质,综述了低共熔溶剂在化学反应、电化学和分离领域的应用,并对低共熔溶剂的发展趋势进行了展望。     

低共熔溶剂在化工领域的应用与进展

作为一种新型的绿色溶剂,低共熔离子液体(DESs)具有实用性、无毒环保、易回收、不易燃以及价格低廉等特点。通过调节低共熔离子液体组成成分的结构和比例,可赋予其特定的功能性及可调变性,因此在很多领域有着越来越广泛的应用。本文介绍了低共熔离子液体,对其基本的理化性能如熔点、黏度、电导率、密度等进行了描述,综述了低共熔离子液体在催化、有机合成、萃取分离、金属电沉积中的应用。     

低共熔溶剂在催化材料制备中的应用研究进展

介绍了低共熔溶剂的主要物理化学性质,总结了低共熔溶剂在光催化材料(二氧化钛、氧化锌、硫化铜等)和功能催化材料(贵金属单质、金属有机骨架)合成中的研究进展,论述了低共熔溶剂在催化材料合成中的特点,探讨了低共熔溶剂在这些材料合成中的作用机理,展望了低共熔溶剂未来的发展方向。     

COSMO-RS模型在离子液体/低共熔溶剂筛选中的应用研究进展

离子液体(ILs)和低共熔溶剂(DESs)作为一类新型的绿色溶剂,由于其独特的物理化学性质,在混合物分离方面已经受到了研究者的广泛关注,因此逐渐成为绿色化学领域的研究重点。针对特定的分离过程,选择合适的溶剂是非常重要的,然而,由于ILs和DESs种类较多,结构复杂,通过实验的方法逐一进行筛选费时费力、成本高,且几乎不可能找到最优选择,因此应用理论计算模型对ILs和DESs进行筛选是非常有必要的。真实溶剂类导体屏蔽模型(COSMO-RS模型)是一种由量子化学计算与统计热力学方法相结合的预测模型,它可以在不需要实验数据的情况下预测液体混合物的热力学性质,已经被研究者广泛用作各种分离问题的快速筛选工具。整理了应用COSMO-RS模型筛选ILs/DESs用于各种油中酚类、含氮化合物、含硫化合物、萜类化合物、天然维生素E的萃取分离,以及CO₂捕获和共沸混合物等的分离过程,表明COSMO-RS模型用于特定混合物萃取溶剂的筛选是快速有效的,可为难分离混合物分离过程中ILs/DESs的预筛选提供有价值的参考。     

New Carvone-Based Deep Eutectic Solvents for Siloxanes Capture from Biogas

During biogas combustion, siloxanes form deposits of SiO₂ on engine components, thus shortening the lifespan of the installation. Therefore, the development of new methods for the purification of biogas is receiving increasing attention. One of the most effective methods is physical absorption with the use of appropriate solvents. According to the principles of green engineering, solvents should be biodegradable, non-toxic, and have a high absorption capacity. Deep eutectic solvents (DES) possess such characteristics. In the literature, due to the very large number of DES combinations, conductor-like screening models for real solvents (COSMO-RS), based on the comparison of siloxane activity coefficient of 90 DESs of various types, were studied. DESs, which have the highest affinity to siloxanes, were synthesized. The most important physicochemical properties of DESs were carefully studied. In order to explain of the mechanism of DES formation, and the interaction between DES and siloxanes, the theoretical studies based on σ-profiles, and experimental studies including the ¹H NMR, ¹³C NMR, and FT-IR spectra, were applied. The obtained results indicated that the new DESs, which were composed of carvone and carboxylic acids, were characterized by the highest affinity to siloxanes. It was shown that the hydrogen bonds between the active ketone group (=O) and the carboxyl group (-COOH) determined the formation of stable DESs with a melting point much lower than those of the individual components. On the other hand, non-bonded interactions mainly determined the effective capture of siloxanes with DES.     

低共熔溶剂的分子结构及物性估算的研究进展

低共熔溶剂具有熔点低、不挥发、不易燃、溶解性良好、易合成、廉价、低毒、腐蚀性低、生物降解性好等特点,常被作为"绿色"溶剂应用于金属加工和合成反应中。然而,目前对低共熔溶剂的结构和性质的研究只限于少部分具体的低共熔溶剂,没有形成系统全面的理论体系。简述了低共熔溶剂的合成与分类、分子结构和形成机理的研究进展,归纳了低共熔溶剂的物性估算方法,并指出了一些关于低共熔溶剂研究中存在的问题,提出了可能的解决方案。     

Separation of Hydrocarbons by Means of Liquid-Liquid Extraction with Deep Eutectic Solvents

Liquid-liquid equilibria for six ternary systems with choline chloride urea or choline chloride glycerol (molar ratio, 1:2) as selective solvent were experimentally determined at atmospheric pressure and 25°C. Equilibrium data were presented with tie lines. Extraction experiments with three-component systems were performed. The suitability of deep eutectic solvents for the separation of pyridine and toluene from n-hexane, and n-butanol from toluene was evaluated in terms of properties of solvents, solute distribution ratio, and extraction efficiency. Choline chloride glycerol has a better potential for separation of pyridine from its mixture with n-hexane. The equilibrium data were well described with the NRTL model.     

Improved Production of 5-Hydroxymethylfurfural in Acidic Deep Eutectic Solvents Using Microwave-Assisted Reactions

Hydroxymethylfurfural (5-HMF) is a key platform chemical, essential for the production of other chemicals, as well as fuels. Despite its importance, the production methods applied so far still lack in sustainability. In this work, acidic deep eutectic solvents (DES), acting both as solvent and catalyst, were studied for the conversion of fructose into 5-HMF using microwave-assisted reactions. These solvents were screened and optimized by varying the hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA). The bio-based solvent γ-valerolactone (GVL) was also applied as additive, leading to a boost in 5-HMF yield. Then, a response surface methodology was applied to further optimize operating conditions, such as reaction time, temperature and wt.% of added GVL. The highest 5-HMF yield attained, after optimization, was 82.4% at 130 °C, in 4 min of reaction time and with the addition of 10 wt.% of GVL. Moreover, a process for 5-HMF recovery and DES reuse was developed through the use of the bio-based solvent 2-methyltetrahydrofuran (2-Me-THF), allowing at least three cycles of 5-HMF production with minimal yield losses, while maintaining the purity of the isolated 5-HMF and the efficacy of the reaction media.     

Computer Simulations of Deep Eutectic Solvents: Challenges,Solutions, and Perspectives

Deep eutectic solvents (DESs) are one of the most rapidly evolving types of solvents, appearing in a broad range of applications, such as nanotechnology, electrochemistry, biomass transformation, pharmaceuticals, membrane technology, biocomposite development, modern 3D-printing, and many others. The range of their applicability continues to expand, which demands the development of new DESs with improved properties. To do so requires an understanding of the fundamental relationship between the structure and properties of DESs. Computer simulation and machine learning techniques provide a fruitful approach as they can predict and reveal physical mechanisms and readily be linked to experiments. This review is devoted to the computational research of DESs and describes technical features of DES simulations and the corresponding perspectives on various DES applications. The aim is to demonstrate the current frontiers of computational research of DESs and discuss future perspectives.     

Effective Release of Intracellular Enzymes by Permeating the Cell Membrane with Hydrophobic Deep Eutectic Solvents

An efficient and green method is crucial for the recovery of intracellular biological products. The major drawbacks of the conventional cell disruption method are nonselectivity and enzyme denaturation. The permeability of hydrophobic deep eutectic solvents (DESs) to the cell membrane was studied, for the first time, and then hydrophobic DESs were innovatively applied to release intracellular enzymes from recombinant Escherichia coli. After optimization, a DES suspension of l -menthol/oleic acid (0.5 %, v/v) showed the highest release yield of intracellular enzyme. Compared with that released by sonication, a release yield of phospholipase D (PLD) of up to 114.58 % was achieved, and the specific activity was increased by 1.96 times. The microstructure of the cell membrane under different treatments was observed by using an electron microscope to understand the permeation of DESs to the cell membrane. The feasibility and applicability of the proposed release method in industrial applications were also demonstrated. The effective and green release method of intracellular enzymes developed herein has bright prospects for industrial application to replace traditional cell disruption methods. A preliminary study on the permeability of hydrophobic DESs to the cell membrane showed that there would be a potential application prospect of hydrophobic DESs not only in releasing intracellular contents, but also in seeking new green penetrating agents.     

低共熔溶剂在天然产物萃取中的应用进展

为了取代传统有毒有害有机溶剂,实现对天然产物的绿色高效萃取,低共熔溶剂(DES)已得到广泛应用和普遍关注。DES是一种新型绿色溶剂,具有易于合成、低毒或无毒及环境友好等优点。通过对近10年各类数据库中相关研究论文的梳理分析,简介了DES的分类、合成及性质,重点阐述低共熔溶剂在萃取天然产物中生物活性物质(如黄酮类化合物、酚类、酚酸、生物碱、多糖、萜类和皂苷类)的应用,尤其是在多糖和黄酮类物质提取工艺中的广泛使用。分析了影响DES萃取效率的主要因素。最后,进一步展望了DES未来的发展趋势和应用前景。     

Elimination of All Free Glycerol and Reduction of Total Glycerol from Palm Oil-Based Biodiesel Using Non-Glycerol Based Deep Eutectic Solvents

Purification of biodiesel prior to utilizing it as an alternative fuel is an essential industrial practice. Low glycerol content is one of the important pointers needed for passing the EN 14214 and ASTM D6751 international biodiesel standards. In this study, choline chloride (ChCl) as salt and ethylene glycol and 2,2,2-Trifluoroacetamide as hydrogen bond donors (HBDs) were employed to synthesize two ammonium salt-non glycerol based Deep Eutectic Solvents (DES). The physical properties of the synthesized DESs were measured and analyzed. These DESs were utilized to remove all the free glycerol from the palm oil-based biodiesel. The results indicated that all the tested DESs were able to remove all free glycerol successfully. The Central Composite Design (CCD) of the Response Surface Methodology (RSM) was used to to experiment design and optimization of total glycerol removal using ethylene glycol-based DESs and 2,2,2-Trifluoroacetamide-based DESs. The maximum total glycerol removal by ethylene glycol-based DESs was obtained at 0.66 ethylene glycol mole fraction and at DES/biodiesel molar ratio of 3 with removal efficiency of 23.85% as well as by 2,2,2-Trifluoroacetamide-based DESs at 0.60 2,2,2-Trifluoroacetamide mole fraction and at DES/biodiesel molar ratio of 2.93 with removal efficiency of 29.29%. The reusability of these DESs for removing free glycerol and total glycerol content from palm oil-based biodiesel was also investigated. This study proves that both ammonium salt-non glycerol based DESs can be successfully employed to remove the glycerol from palm oil-based biodiesel.     

Removal of Dibenzothiophene from Diesels by Extraction and Catalytic Oxidation with Acetamide‐Based Deep Eutectic Solvents

A series of acetamide‐based deep eutectic solvents (DESs) with different proportions were prepared. Extraction and catalytic oxidation desulfurization (ECODS) of the acetamide‐based DESs were investigated and the process was optimized. Such DESs with a molar ratio of acetamide and p‐TsOH of 1/3 (C₂H₅NO/3p‐TsOH) exhibits such a remarkable catalytic activity that the dibenzothiophene (DBT) removal could reach 100 % under optimized conditions. C₂H₅NO/3p‐TsOH was used for the oxidative desulfurization of actual commercial diesel. The sulfur removal of diesel achieved up to 98 %. C₂H₅NO/3p‐TsOH could be recycled six times and the desulfurization activity was slightly decreased. Evaluation of the mechanism indicated that oxidative desulfurization (ODS) was realized via dual activation of acetamide‐based DESs. A novel and effective way for deep desulfurization of diesel is provided.     

Intensification of Mass Transfer in the Extraction Process with a Nanofluid Prepared in a Natural Deep Eutectic Solvent

The phytotoxic residues after olive oil production and residue leaves after pruning contain valuable bioactive compounds. A natural deep eutectic solvent (NADES) and an ethanol-water mixture were used for polyphenol extraction from olive pomace and leaves. Type of solvent, extraction temperature, and particle size of the leaves were optimized. NADES demonstrated better efficiency in the extraction process than conventional solvents; with higher temperature and smaller fraction of olive leaves, a higher yield of polyphenols was obtained from leaves. Extraction with a nanofluid as solvent was carried out. A stable nanofluid was prepared from NADES by adding Al₂O₃ nanoparticles. A higher yield was obtained with nanofluid from leaves, while an improvement of polyphenol extraction was achieved after the removal of oil from olive pomace.