离子液体/低共熔溶剂在煤基液体分离中的应用

为了实现煤基液体各组分利用价值最大化,本文综述了离子液体和低共熔溶剂对组分组成复杂的煤基液体进行高效萃取分离的研究进展。首先介绍了离子液体和低共熔溶剂的性质及分类;其次根据分离目标的不同,将离子液体和低共熔溶剂对煤基液体典型组分的萃取分离分为四个方面进行阐述:煤基液体提酚、燃料油萃取脱硫、燃料油萃取脱氮、芳烃和脂肪烃的分离。分析表明,离子液体和低共熔溶剂对实际煤基液体的提酚效果较好,能分离出绝大多数的酚类化合物;燃料油萃取脱硫时,离子液体和低共熔溶剂对实际煤基液体的单次脱硫率均不高,需3～5次重复萃取后才能获得理想效果;燃料油中的碱性及非碱性含氮化合物很难被同一种离子液体或低共熔溶剂一次性分离出,导致实际油品的脱氮率较低;大多数离子液体和低共熔溶剂进行芳烃和脂肪烃的分离时不能获得理想的分配系数和选择性,尚无法用于实际芳烃和脂肪烃的分离。氢键、π-π、CH-π、范德华力等分子间相互作用的差异是实现离子液体或低共熔溶剂进行煤基液体典型组分分离的主要原因。依据分离对象,设计合适的离子液体和低共熔溶剂,提高实际煤基液体分离时的萃取率和选择性;分析并解决离子液体和低共熔溶剂用于实际煤基液体各组分...     

热可逆离子液体-低共熔溶剂双水相体系的相行为及理化特性研究

与聚合物双水相体系相比,离子液体双水相体系具有相分离效率高和选择性强的特点,在萃取领域得到了广泛关注。然而,离子液体双水相体系中常见的kosmotropic组分为无机盐或有机盐,溶液环境通常呈现强碱性,不利于保持萃取分子的稳定性和生物活性。以低共熔溶剂替代盐类作为kosmotropic组分、以离子液体为chaotropic组分构建新型离子液体-低共熔溶剂双水相体系,考察了不同温度下的相行为规律,筛选出具有高临界共熔温度（UCST）和低临界共熔温度（LCST）两种截然相反的热可逆相转变行为的萃取体系,从宏观角度探索了离子液体-低共熔溶剂-水三元体系的黏度、密度、电导率以及pH等理化特性随温度变化的规律,利用量子化学计算从微观角度分析离子液体、低共熔溶剂与水分子之间的相互作用。研究旨在揭示热可逆离子液体-低共熔溶剂双水相体系的成相机理,为萃取温敏性生物分子设计新的理想萃取体系提供基础数据。     

Acidic protic ionic liquid-based deep eutectic solvents capturing SO2 with low enthalpy changes

With the aim of lowering energy consumption for gas regeneration, rational design of absorbents with low absorption enthalpy changes while retaining good gas solubility is of both scientific and practical significance. Herein, we demonstrated that acidic protic ionic liquid (APIL)-based deep eutectic solvents (DESs), which comprise N-ethylimidazole hydrochloride ([EimH]Cl) and ethylene glycol (EG), were able to reversibly absorb SO₂ with high solubility (11.60 mol kg⁻¹) and SO₂/CO₂ selectivity (655) at 293.2 K and 101.3 kPa. Meanwhile, [EimH]Cl/EG DESs exhibit very low enthalpy changes (Δ_rH_m) ranging from −27.1 to −25.6 kJ mol⁻¹, and thus ease of desorption at very mild temperature conditions (303.2 K) with desorption ratios up to 99.6%. Recycling experiments showed that no obvious loss in capacity was found after six absorption–desorption cycles, suggesting good regeneration performance of [EimH]Cl/EG DESs. Moreover, spectroscopic analysis revealed the charge-transfer interaction between [EimH]Cl/EG and SO₂.     

离子液体/低共熔溶剂用于NH3分离过程的热力学分析

氨气（NH₃）作为一种有害气体,其传统吸收技术存在诸多缺陷,亟需开发性能优越的NH₃吸收剂,以开发新型NH₃分离技术。离子液体和低共熔溶剂作为气体分离过程的潜在吸收剂,因低挥发性、良好的热稳定性以及灵活的可调控性等特点受到越来越多的关注。但离子液体和低共熔溶剂数量众多,筛选困难。采用热力学分析方法分析离子液体和低共熔溶剂用于NH₃分离过程,基于Gibbs自由能变,拟合出分离过程的最佳操作条件,将总能耗和离子液体用量作为筛选标准,筛选出性能良好的[Omim][BF₄]。将[Omim][BF₄]与传统NH₃吸收剂水对比,发现[Omim][BF₄]具有更低的能耗。最后,拟合出筛选标准与离子液体/低共熔溶剂的临界性质间的规律,为开发新的NH₃吸收剂和新的分离技术提供依据。     

离子液体和低共熔溶剂催化二氧化碳合成有机碳酸酯的研究进展

离子液体和低共熔溶剂因其良好的溶解与催化能力,可催化CO₂转化为高附加值化学品。本文综述了离子液体和低共熔溶剂催化CO₂转化为有机碳酸酯的研究进展,分析了CO₂与醇生成直链碳酸酯以及与环氧化物生成环状碳酸酯的反应机理;介绍了传统型、质子型、功能化离子液体以及由氯化胆碱、季铵盐与季膦盐、有机碱等作为氢键受体组成的低共熔溶剂,及其在CO₂转化为直链和环状碳酸酯反应中的催化性能;总结了此两类反应中离子液体和低共熔溶剂设计的基本规律;指出了CO₂转化反应中离子液体与低共熔溶剂存在的催化效率低、稳定性不高、后续分离困难等问题,后续研究可结合计算机辅助设计方法,探索更合适的阴阳离子/氢键供受体组合,获得更高效的催化体系。     

Deep eutectic ionic liquids based on DABCO-derived quaternary ammonium salts: A promising reaction medium in gaining access to terpyridines

Owing to the directional H-bonding,coordination and π-stacking abilities,terpyridines have been widely used as supramolecular tectons in molecular architectures,skeletons in molecular devices and metallopolymers,and are gaining importance in medicinal chemistry.In this paper,we have synthesized,characterized and applied deep eutectic ionic liquids (DEILs) based on 1,4-diazabicyclo[2.2.2]octane;triethylenediamine (DABCO)-derived quatemary ammonium salts for the preparation ofterpyridines.These DEILs were synthesized through N-alkylation of DABCO with haloalkanes (1-bromopentane or 1-bromoheptane) followed by mixing and heating with methanol or polyethylene glycol as a hydrogen bond donor.The synthesized DEILs were structurally characterized by IR and NMR.The formation of deep eutectic solvent was confirmed by freezing point depression,it composition was investigated through phase diagram,and its thermal stability was determined through differential scanning calorimetry,derivative thermogravimetry and thermal gravimetric analysis studies.Further,these DEILs were investigated for their effectiveness towards synthesis of 2,2':6',2"-terpyridine,3,2':6',3"-terpyridineand 4,2':6',4"-terpyridine derivatives through Kr(o)hnke reaction.The results show that these three types ofterpyridines can be obtained in reasonable yields (80%-97%) by the one-pot reaction of 2-,3-or 4-acetylpyridine with a variety of aromatic aldehydes in the presence of DEIL as a reaction medium,sodium hydroxide as a base and ammonium acetate as a cyclizing agent.This methodology is highly efficient and cost-effective for synthesis of symmetrical as well as unsymmetrical terpyridines.Importantly,these DEILs can be reused several times without an obvious loss of activity and are non-toxic,low-volatile,biodegradable and highly thermally stable.Therefore,these DEILs as a non-conventional reaction medium for the synthesis of terpyridines provides appealing opportunities to be investigated in the domain of green synthesis.     

High-efficiency separation of oil sands using ChCl-based deep eutectic solvents

Deep eutectic solvents (DESs) are a kind of potential lixiviant for extraction processing. Unlike conventional ionic liquids (ILs), DESs are relatively cheap and environmentally friendly. Herein, three different ChCl-based DESs, namely, choline chloride/urea, choline chloride/ethylene glycol, as well as choline chloride/propandioic acid, were synthesized and used to enhance bitumen recovery from oil sand by petroleum ether extraction. The results showed a multiphase system formed after mixing the components at ~25°C, consisting of sands and clays, a DES layer, and a petroleum ether layer containing the bitumen. These DESs were immiscible with bitumen or petroleum ether. Coupled with a density difference, a clear phase separation was presented between the bitumen–petroleum ether mixture and DES. The DES functioned as a separating agent, keeping the petroleum ether–bitumen mixture and spent sand apart from each other. The results showed that the bitumen recovery was increased by ~12% compared with that without the DESs. We deduced that the enhancement in the separation may result from the reduction of adhesion between bitumen and sand by the DESs. The ChCl-based DESs and petroleum ether could be readily recycled to reduce industrial costs. After 10 cycles, the bitumen recovery remained above 86%.     

Design of highly stretchable deep eutectic solvent-based ionic gel electrolyte with high ionic conductivity by the addition of zwitterion ion dissociators for flexible supercapacitor

Nonvolatile deep eutectic solvent (DES) electrolytes with good electrochemical stability have recently emerged as promising electrolytes for energy storage devices. In this report, for the first time a polymerized zwitterionic molecule was introduced and a series of hybrid cross-linked zwitterion-containing copolymer DES gels are synthesized via UV initiated free-radical copolymerization of acrylic acid (AA), sulfobetaine vinylimidazole (VIPS) and poly(ethylene glycol) diacrylate (PEGDA) monomers, in situ within DES, which is prepared from 1:2 M ratio of choline chloride and ethylene glycol. Systematically varying the AA:VIPS molar ratio and copolymer contents within the copolymer network enables one to widely tune the mechanical properties and ionic conductivity of the poly(AA-co-VIPS) DES gels. The tensile strength of P(AA-co-VIPS) DES gels significantly increased from 28 kPa to 176 kPa with fracture strain from 720% to 1370%, while the ionic conductivity of copolymer DES gels remains high from 2.7 to 4.1 mS cm⁻¹ with the increase of copolymer content from 25 wt % to 45 wt%. A copolymer DES gel not only enables a supercapacitor deliver high capacitance of 71.52 F g⁻¹ at 0.5 A g⁻¹, and retains ∼97% of its capacitance after 2000 cycles, but also achieves outstanding capacitive performance over wide temperature range.     

低共熔法萃取分离油酚混合物过程中油的夹带

采用季铵盐与酚形成低共熔溶剂(DES)从含酚的混合物中萃取分离酚是一种有效的油酚分离方法, 然而分离过程中, 中性油的夹带会影响分离效率。以含苯酚200 g·L^-1的甲苯溶液作为模拟油酚混合物, 氯化胆碱(ChCl)作为分离剂, 研究了氯化胆碱的加入量、萃取温度(25～55℃)及模拟油中直链烷烃的浓度等因素对酚的萃取分离及中性油夹带的影响。结果表明, 随着ChCl加入量增大, 酚萃取率升高, 中性油的夹带量减少;ChCl过量时, 酚的萃取量恒定且达到极大值, 中性油夹带量恒定且夹带量最小;萃取温度对酚的萃取率影响不大, 对中性油的夹带量在ChCl加入量不足时随温度升高而增多, 当ChCl加入量足量时与温度变化关系不大;模拟油中直链烷烃的浓度不影响萃取效率, 浓度越高, 甲苯夹带越少。以ChCl萃取含苯酚200 g·L^-1的甲苯溶液, 在萃取温度25℃、ChCl加入量大于0.6(与酚的摩尔比)的条件下, 苯酚萃取率达95%, 甲苯夹带率为15%, 70℃条件下氮气吹扫60 min内可将DES中甲苯完全去除。     

Hydrophobic deep eutectic solvent-based ionic conductive gels with highly stretchable,fatigue-resistant and adhesive performances for reliable flexible strain sensors

Owing to the advantages of temperature resistance, low cost, and biocompatibility, deep eutectic solvent (DES)-based ionic conductive gels have attracted increasing research interest for flexible devices in recent years. However, current DES gels are all based on hydrophilic DES, which tend to absorb a large amount of environmental moisture, resulting in gel softening and adversely affecting the durability of the device. In this work, we highlight for the first time that N,N-dimethylacrylamide monomer, and the obtained polymer can form hydrogen-bonding networks with hydrophobic DES, methyl trioctyl ammonium chloride/ethyl 4-hydroxybenzoate (1:2), thereby obtaining a hydrophobic DES-based gel through photo-polymerization. The resultant DES gel displays high stretchability (~900%), toughness (341.14 kJ m⁻³), anti-fatigue property (recovery after 500 compression cycles), desirable conductivity (0.12 mS cm⁻¹), adhesiveness and high transparency (>90% visible light transmittance). Notably, the hydrophobic DES-based gel absorbs only 2 wt% water but exhibits significant water-induced stiffening after exposing in ambient air for 1 week. These properties lead to the successful realization of the DES gels as wearable sensors to precisely monitor human motion. This work may open new avenues for the development of hydrophobic DES-based gel ionotronics with functional performance.     

Extractive desulfurisation of gasoline with tetrabutyl ammonium chloride-based deep eutectic solvents

In this study, three tetrabutyl ammonium chloride (TBAC)-based deep eutectic solvents (DESs) were synthesised and used for desulfurising model and real gasolines. Extraction efficiencies of different DESs followed the order of TBAC/ethylene glycol > TBAC/glycerol > TBAC/malonic acid. After five extraction cycles, the extraction efficiencies of TBAC/ethylene glycol, TBAC/glycerol and TBAC/malonic acid reached 99.5, 99.3 and 99.2%, respectively. Additionally, the structures of original and recycled DESs were analysed and the results showed that DESs maintained their original structures after regeneration. Finally, the desulfurisation performance of DESs for real gasoline was also investigated. This work will provide new green extractants for gasoline desulfurisation.     

Effective separation of aromatic hydrocarbons by pyridine‐based deep eutectic solvents

Many promising qualities of deep‐eutectic solvents made them suitable solvents in separation process. In this work, the pyridine‐based deep eutectic solvents were designed and synthesized with N‐ethylpyridinium bromide and two HBDs (N‐formyl morpholine and levulinic acid). Two ternary systems, benzene + cyclohexane + DES and toluene + n‐heptane + DES, were studied by the liquid‐liquid extraction. The effect of different HBDs, extraction time, volume ratio of DES to system solution, and the initial concentration of aromatic were studied. The DES with N‐formyl morpholine showed better separation performance than that with levulinic acid. The liquid‐liquid extraction equilibrium could be obtained in 10 minutes. The volume ratio of DES to system solution was set as 1:1. Both DESs showed their best separation performance at low temperatures (20°C) and low aromatic concentration system. For the benzene + cyclohexane system, the distribution coefficient of benzene was 1.733 and the selectivity was 23.8 at 20°C. For the toluene + n‐heptane system, the distribution coefficient of toluene was 0.853 and the selectivity was 40.7. Tie‐lines for two ternary systems were obtained, and the Othmer‐Tobias correlation was used to check the reliability of the obtained liquid‐liquid extraction experimental data. The experimental LLE data were correlated using the NRTL model and the calculated data correlated significantly with the experimental data.     

胆碱类低共融溶剂在CO2捕集与分离中的应用

胆碱类低共融溶剂是一种新型的离子液体。它不仅具有传统离子液体的优点,还具有价格低廉、低毒、生物可降解等优势。对胆碱类低共融溶剂在CO₂捕集与分离中所涉及的物理性质,如气体的溶解度、CO₂的吸收-解吸、密度、稳定性、黏度和表面张力等进行考察,并分析了胆碱类低共融溶剂的结构对各物性的影响。通过与传统离子液体的对比,胆碱类低共融溶剂在CO₂捕集与分离中的应用具有一定的优势,如CO₂溶解度高,黏度低。然而,胆碱类低共融溶剂在气体的选择性分离、表面张力等的研究还不足,且热稳定性方面还存在瓶颈,因此,其在CO₂捕集和分离中的应用还有待进一步探讨。     

Protic ionic liquid-based deep eutectic solvents with multiple hydrogen bonding sites for efficient absorption of NH3

The emerging of ionic liquids (ILs) provides an efficient and sustainable way to separate and recover NH₃ due to their unique properties. However, the solid or highly viscous ILs are not suitable for traditional scrubbing. Therefore, an effective strategy was proposed by combining the protic ILs (PILs) with acidic H and low viscous ethylene glycol (EG) to form IL-based deep eutectic solvents (DESs) for NH₃ absorption. The results indicated that these PIL-based DESs not only have fast absorption rate, but also exhibit exceptional NH₃ capacity and excellent recyclability. The highest mass capacity of 211 mg NH₃/g DES was achieved by [Im][NO₃]/EG with molar ratio of 1:3, and was higher than all the reported ILs and IL-based DESs, which was originated from multiple hydrogen bonding between acidic H and hydroxyl groups of the DESs and NH₃. This work will provide useful idea for designing IL-based solvents for NH₃ separation applications.     

Ionic liquids and deep eutectic solvents for biodiesel synthesis: a review

During the past decade, ionic liquids (ILs) have gained tremendous attention in nearly every branch of the chemical and physical sciences as designer (task‐driven) and budding ‘green’ solvent alternatives to conventional volatile organics. In particular, with a more in‐depth understanding of their physicochemical properties, the active exploration of ILs as alternative solvents and/or catalysts in the chemical or enzymatic (biocatalytic) production of biodiesel has gained momentum. Most excitingly, very recent developments in the science of deep eutectic solvents (DESs) have initiated potentially more cost‐effective approaches to biodiesel synthesis. At this stage, there is sufficient research completed to provide an important opportunity to stand back and assess the progress in the field, critically examining the strengths and limitations for IL and DES technology in biodiesel synthesis. No such comprehensive evaluation exists. This work, therefore, seeks to bridge this gap by systematically reviewing the reported methods for biodiesel production which make use of ILs, either as (co)solvent components or catalysts, highlighting existing problems and limitations, with an emphasis placed on the future research required to bypass the hurdles to employing ILs in commercial biodiesel production. Copyright © 2012 Society of Chemical Industry     

深共融溶剂法合成盐酸吗啉双胍

在吗啉盐酸盐和双氰胺组成的深共融溶剂体系的条件下,以吗啉、浓盐酸、双氰胺为原料通过缩合反应合成盐酸吗啉双胍。讨论反应温度、时间、反应物摩尔比等因素对盐酸吗啉双胍合成收率的影响,重点考察深共融溶剂体系组分间不同摩尔比对体系熔点的影响,以及研究产物的分离和纯化的方法。研究结果表明:在由吗啉盐酸盐和双氰胺组成的深共融溶剂体系的条件下以吗啉、浓盐酸、双氰胺为原料通过缩合反应合成盐酸吗啉双胍的方法简单,产品易于分离。吗啉盐酸盐/双氰胺(mol)为1.0∶0.8和1.0∶1.8时,深共融溶剂体系熔点为48℃。通过对影响因素的考察,找到了使用该法合成盐酸吗啉双胍的最佳合成条件:缩合反应温度为140℃;最佳反应时间为3h;物料配比(mol)为1∶0.8。     

咪唑类三元低共熔溶剂捕集低压SO2的实验研究

近几年来,以氢键受体（HBA）和氢键供体（HBD）组成的低共熔溶剂（DESs）以其类似于离子液体的性质被认为是一种有潜力的SO₂吸附剂。为制备用于低压SO₂吸收的容量大、价格合理、循环性能好的低共熔溶剂,选用咪唑(Im)作为功能化组分,以价格低廉的甘油(Gly)、PEG200和乙二醇(EG)作为第二HBD,与作为HBA的氯化胆碱(CC)构建CC-GIy-Im、CC-PEG200-Im、CC-EG-Im三元功能化低共熔溶剂,并用于低压SO₂的捕集实验研究。着重考察了第二HBD种类、咪唑含量、温度等因素对DESs吸收SO₂的性能影响。结果表明：在所选的第二HBD中,PEG200的性能最佳,其构建的低共熔溶剂密度、黏度适中,热稳定性好,吸收性好;CC-PEG200-Im（1∶2∶7）在40℃下,对1% SO₂的吸收量达到0.236 g SO₂/g DES;经5次吸收-解吸循环后,低共熔溶剂吸收性能仍然稳定;¹H NMR谱图分析结果表明,CC-PEG200-Im对SO₂的吸收机理为化学吸收。     

ChCl-urea-ZnO-Cu2O低共熔溶剂电镀铜锌合金

以ChCl-urea-ZnO-Cu₂O低共熔溶剂为电解质在343 K镍基体上电沉积制备得到了铜锌合金镀层。伏安曲线测试表明在沉积过程中,镍基体能够诱导金属Zn发生欠电位沉积,从而实现了Cu-Zn合金的共沉积。同时研究了沉积电势对镀层成分和形貌的影响,结果表明：沉积电势由-0.85 V （vs Ag）增加到-1.3 V （vs Ag）时,合金镀层中Zn原子百分数从0升高到76.29%。在沉积电势为-1.10～-1.15 V范围内,Zn原子百分数为12.5%～20.81%时,镀层平整致密,颜色为金色,达到仿金镀的效果。     

Remarkable NH3 absorption in metal-based deep eutectic solvents by multiple coordination and hydrogen-bond interaction

The elimination and recycling of NH₃ from the vented circulating stream of NH₃ synthesis process is of great significance to the protection of air environment and saving of NH₃ product. Deep eutectic solvents (DESs) with as many weak acidic sites as possible are anticipated to exhibit high efficiency for NH₃ absorption at low pressures. Herein, we designed and prepared a series of metal-based DESs by mixing EaCl, metal chloride (SnCl₂, ZnCl₂, FeCl₃, or CoCl₂), and Gly. The physiochemical properties, NH₃ absorption performance, and mechanism of prepared metal-based DESs were investigated systematically. It is found that considerably high solubilities of NH₃ in DESs can be achieved by utilizing the multiple coordination and hydrogen-bond interaction with NH₃ provided by metal ions and Gly respectively. The values of NH₃ solubilities (17.55 mol/kg at 298.2 K and 103.0 kPa, and 10.24 mol/kg at 298.2 K and 6.8 kPa) are the highest reported to date.