微波控制下咪唑类离子液体的制备

以N-甲基咪唑和氯代正丁烷为原料在微波控制下合成了离子液体1-丁基-3-甲基咪唑氯盐([BMIm]Cl),对产物的结构作了红外光谱、核磁共振等分析。用该离子液体溶解纤维素,溶解度良好,并对溶解前后纤维素的结构变化、溶解机理进行了研究。     

离子液体[Bmim]PF6萃取红霉素动力学机理

研究探讨离子液体[Bmim]PF6萃取红霉素过程的动力学行为和特征,考察了温度以及传质界面积对萃取速率的影响。结果表明,离子液体[Bmim]PF6萃取红霉素的过程为化学反应控制过程,并确定萃取平衡方程式。一级反应动力学模型能很好的描述实验条件下离子液体对红霉素的萃取分离过程。     

Efficient capture of carbon dioxide with novel mass‐transfer intensification device using ionic liquids

A novel mass‐transfer intensified approach for CO₂ capture with ionic liquids (ILs) using rotating packed bed (RPB) reactor was presented. This new approach combined the advantages of RPB as a high mass‐transfer intensification device for viscous system and IL as a novel, environmentally benign CO₂ capture media with high thermal stability and extremely low volatility. Amino‐functionalized IL (2‐hydroxyethyl)‐trimethyl‐ammonium (S)?2‐pyrrolidinecarboxylic acid salt ([Choline][Pro]) was synthesized to perform experimental examination of CO₂ capture by chemical absorption. In RPB, it took only 0.2 s to reach 0.2 mol CO₂/mol IL at 293 K, indicating that RPB was kinetically favorable to absorption of CO₂ in IL because of its efficient mass‐transfer intensification. The effects of operation parameters on CO₂ removal efficiency and IL absorbent capacity were studied. In addition, a model based on penetration theory was proposed to explore the mechanism of gas–liquid mass transfer of ILs system in RPB. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2957–2965, 2013     

Microwave heating coupled with ionic liquids: Synthesis and properties of novel optically active polyamides, thermal degradation and electrochemical stability on multi-walled carbon nanotubes electrode

Rapid and efficient synthesis of novel optically active polyamides (PAs) was achieved under microwave irradiation. Thus, step-growth polymerization of a novel chiral diacid containing naphthalimide and flexible chiral groups with different diisocyanates in the presence of a small amount of ionic liquids that act as a primary microwave absorber as well as conventional heating was carried out. The PAs were characterized using FT-IR, ¹H NMR, UV-vis spectroscopy, fluorimetry and elemental analysis. Thermal properties of new PAs were evaluated by thermogravimetric analysis and differential scanning calorimetry. The interpretation of kinetic parameters (E, ΔH, ΔS and ΔG) of thermal decomposition stages has been evaluated using Coats-Redfern equations. Here also for the first time we report an electrochemical oxidation method based on the adsorptive stripping cyclic voltammetry technique on the multi-walled carbon nanotube-modified glassy carbon electrode for the investigation of electrochemical stability of the resulting polymers in aqueous solution at various pH values.     

Polyoxometalate-based ionic liquids as catalysts for deep desulfurization of fuels

In order to obtain the ultra low-sulfur diesel, deep desulfurization of diesel oil has become a vital subject of environmental catalysis studies. Extraction and catalytic oxidation desulfurization (ECODS) system is one of the most promising desulfurization processes. A series of Keggin-type POM-based ionic liquids hybrid materials [MIMPS]₃PW₁₂O₄₀·2H₂O (1-(3-sulfonic group) propyl-3-methyl imidazolium phosphotungstate), [Bmim]₃PW₁₂O₄₀ (1-butyl 3-methyl imidazolium phosphotungstate), [Bmim]₃PMo₁₂O₄₀ (1-butyl 3-methyl imidazolium phosphomolybdate) and [Bmim]₄SiW₁₂O₄₀ (1-butyl-3-methyl imidazolium silicotungstate) have been developed in this study, and the reaction has performed using the POM-ILs materials as catalysts, H₂O₂ as oxidant, and ionic liquid (IL) as solvent. Through experimental evaluations, [MIMPS]₃PW₁₂O₄₀·2H₂O was found to be the best catalyst, with an S-removal of 100% at 30 °C for 1 h. The main factors affecting the process including temperature, catalyst dosage, and O/S (H₂O₂/DBT) molar ratio were investigated in detail. Under the optimal conditions, DBT (dibenzothiophene) and 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) could achieve high desulfurization efficiency. Moreover, the reaction system also exhibited high activity in actual diesel oil, which could be reduced from 1113 ppm to 198 ppm. The reaction system could recycle 8-times with a slight decrease in activity.     

3种离子液体催化剂的制备以及在以微生物油脂合成生物柴油过程中的应用研究

针对原料油在转化成生物柴油的过程中易使催化剂失活等问题,合成了3种离子液体:氯化1-丁基-3-甲基咪唑盐([ BMIm] Cl)、1-丁基-3-甲基咪唑氟硼酸盐([BMIm] BF4)、1-丁基-3-甲基咪唑六氟磷酸盐([BMIm] PF6),并对合成的产物作了紫外光谱、红外光谱、核磁共振的结构表征.3种离子液体催化剂均用于催化自制微生物油脂交换制备生物柴油.结果表明,在醇油摩尔比n(醇)∶n(油)=15∶1、催化剂用量为原料油质量的10％、反应温度为90℃、反应时间为16 h的条件下,生物柴油产率可达95％以上.[BMIm] PF6相较于其他2种离子液体催化剂具有较高的催化活性和产率,且与产品易于分离,重复使用6次以后,仍然保持良好的催化活性,产率仍保持在90％以上,说明其在生物柴油生产产业具有广泛应用的潜质.     

Molecular understanding of pyridinium ionic liquids as absorbents with water as refrigerant for use in heat pumps

Aiming at developing new absorbent/refrigerant working pairs for heat pumps, thermodynamic and transport properties of two pyridinium ionic liquids (ILs), N‐ethylpyridinium bis(trifluoromethanesulfonyl)amide and N‐ethylpyridinium trifluoromethanesulfonate were studied using molecular simulation and nuclear magnetic resonance techniques. The microscopic structure of the ILs and the solvation environment of water, including hydrogen bonding, were studied. Free‐energies of solvation of water were obtained using perturbation methods, and the values agree with experimental observations. Self‐diffusion coefficients and viscosity were computed and compared with nuclear magnetic resonance measurements and literature. Simulations predict slower dynamics when compared with experiment: diffusion coefficients are underpredicted, whereas viscosity is overpredicted. As such, simulation is consistent in a Stokes‐Einstein sense. The trends in transport properties due to changing anion, to the presence of water and the effect of temperature are well predicted. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3523–3531, 2017     

固定分离CO2离子液体的合成进展

因具有性质稳定、无挥发、CO2溶解能力强、产物易于分离、循环使用性高等特点,离子液体可望替代传统有机吸收剂用于气相CO2的固定分离.在简述其应用概况的基础上,主要综述了近期国内外此类离子液体(主要分为常规型和功能型两种)的合成方法的研究进展,并对功能型离子液体和相关材料的绿色合成方向进行了展望.     

Viscosity of ionic liquids: Database,observation, and quantitative structure‐property relationship analysis

Viscosity data for ionic liquids (ILs) are needed for the theoretical study on viscosity or for the design/development of industrial process that involves ILs; understanding the relationship between ionic structure and viscosity is also desired to more rationally design and synthesize ILs with ideal viscosity. A database for the viscosity of pure ILs and their binary/ternary mixtures with molecular compounds is created by performing a comprehensive collection from published scientific literature sources worldwide covering the period from 1970 to 2009. In this database, there are 5046 data entries, 696 ILs, 306 cations, and 138 anions. Following the database, a direct observation of the effects of ionic structure along with temperature, pressure, and impurity on the viscosity is summarized, and a quantitative structure‐property relationship (QSPR) correlation is performed to understand the viscosity at a micro‐electronic or molecular level. Through direct observation and QSPR, the relationship between ILs structure and viscosity is addressed. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

N,N-dialkylimidazolium dialkylphosphate ionic liquids: Their extractive performance for thiophene series compounds from fuel oils versus the length of alkyl group

N-butylimidazole-derived dialkylphosphate ionic liquids (ILs) are demonstrated to be effective for extractive removal of aromatic sulfur compounds (S-compounds) from fuel oils, and show strong preferential extraction for aromatic S-compound versus toluene. Sulfur partition coefficients (K_N) between IL and fuel oil at 298.15 K are determined experimentally over a wide range of sulfur content. The results show that the sulfur removal selectivity for a specific IL is dependent on the molecular structure of the S-compounds and follows the order dibenzothiophene > benzothiophene > thiophene > 3-methylthiophene, and the efficiency of the ILs for removal of aromatic S-compounds is dependent on the size and structure of both cations and anions of the ILs. For the dialkylphosphate ILs studied with the same anion, the longer the alkyl substitute to the imidazolium ring is the higher the K_N value for that IL, and a similar trend is found for the ILs with same cation.     

高活性Br(o)nsted离子液体催化酯化反应

制备了两种基于4-二甲氨基吡啶(DMAP)的、对水和空气稳定的、带-SO3H官能团的Br(o)nsted酸离子液体,它们具有高的催化活性、很好的稳定性、可以循环使用、对环境友好,用于催化十三烷二酸与醇反应制备一系列二元酸酯,收率达到80%,二元酸酯选择性达到100%,且催化剂易与产物二元酸酯分离.     

Enhanced gravimetric CO2 capacity and viscosity for ionic liquids with cyanopyrrolide anion

Ionic Liquids (ILs) are considered as alternative solvents for the separation of CO₂ from flue gas due mainly to their CO₂ affinity and thermal stability. The cation architecture in a matrix of ammonium and mostly phosphonium‐based ILs with 2‐cyanopyrrolide as the anion to evaluate its impact on gravimetric CO₂ absorption capacity, viscosity, and thermal stability and the three fundamental properties vital for application realization are systematically investigated. Among the investigated ILs, [P2,2,2,8][2‐CNpyr] demonstrated the lowest viscosity, 95 cP at 40°C, and highest CO₂ uptake, 114 mg CO₂ per g IL at 40°C. Combined effects of asymmetry and the optimized chain lengths also resulted in improved thermal stability for [P2,2,2,8][2‐CNpyr], with a mass loss rate of 1.35 × 10^?6 g h^?1 (0.0067 mass % h^?1) at 80°C. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2280–2285, 2015     

Structure‐based model for prediction of electrical conductivity of pure ionic liquids

A structure‐based method was proposed to estimate the electrical conductivity of ionic liquids covering wide ranges of temperature (238.15–484.1 K) and electrical conductivity (0.0001524–19.3 S/m) based on experimental data collect from literature from 1998 to 2015. The influences of temperature and ion structure on electrical conductivity were also discussed. The mean absolute percentage error between the calculated and literature data was 6.02%, with 6.12% for the training set (1978 data points, 177 ILs) and 5.10% for the test set (217 data points, 11 ILs). © 2016 American Institute of Chemical Engineers AIChE J, 62: 3751–3762, 2016     

咪唑盐离子液体的微波合成、表征及性质研究

通过微波辐射,在无溶剂的状态下以N-甲基咪唑为原料合成了4种氯化1-烷基-3-甲基咪唑盐([Bmim]Cl、[Omim]Cl、[C_12mim]Cl、[C_16mim]Cl)离子液体,并测定了离子液体的表面张力和吸水性能.     

Measurement of activity coefficients at infinite dilution for hydrocarbons in imidazolium-based ionic liquids and QSPR model

The separations of olefin/paraffin, aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers. Activity coefficients γ ^∞ at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation. In fact, the measurement of γ ⁻⁸ by gas-liquid chromatography is a speedy and cost-saving method. Activity coefficients at infinite dilution of hydrocarbon solutes, such as alkanes, hexenes, alkylbenzenes, styrene, in 1-allyl-3-methylimidazolium tetrafluoroborate ([AMIM][BF₄]) and 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM][PF₆]), 1-isobutenyl-3-methylimidazolium tetrafluoroborate ([MPMIM][BF₄]) and [MPMIM][BF₄]-AgBF₄ have been determined by gas-liquid chromatography using ionic liquids as stationary phase. The measurements were carried out at different temperatures from 298 to 318 K. The separating effects of these ionic liquids for alkanes/hexane, aliphatic hydrocarbons/benzene and hexene isomers have been discussed. The hydrophobic parameter, dipole element, frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method. The quantitative relations among the computed structure parameters and activity coefficients at infinite dilution were also developed. The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.     

A review of ionic liquids as catalysts for transesterification reactions of biodiesel and glycerol carbonate production

Biodiesel production has been rapidly increasing due to the strong governmental policies and incentives provided leading to an oversupply of its by-product, glycerol. Therefore, finding ways of utilizing glycerol is essential to increase the net energy and sustainability of biodiesel. Ionic liquids have been used successfully as catalyst for both the production of biodiesel and the conversion of glycerol to glycerol carbonate. These catalysts are relatively environmentally friendly as they have the potential to enable sustainable processes. Herein, the prospect of using ionic liquids to catalyze transesterification triglycerides for the production of biodiesel and the conversion of glycerol to glycerol carbonate will be discussed. Elucidation of the reaction mechanism is expected to provide an in-depth understanding of the process with respect to the effects of cation and anion based on the reactions of interest.     

离子液体与树脂催化合成醋酸正丁酯的动力学比较

以阳离子交换树脂AMBERLYST15和各种离子液体为催化剂,研究了醋酸和正丁醇反应生成醋酸正丁酯的动力学。实验测定了催化剂种类、反应温度和催化剂量对反应速率的影响,并用拟均相模型对实验数据拟合。在实验条件下,发现AMBERLYST15和己内酰胺四氟硼酸盐催化效率很高,表观活化能分别为36.69,37.06kJ/g,指前因子分别为120.0,61.50m3/(g.h)。结果表明,树脂AMBERLYST15和己内酰胺四氟硼酸盐离子液体二类催化反应的活化能相近,指前因子却相差很大,2种催化剂在相同的催化机理下有不同的催化效率。     

Mass‐transfer rate enhancement for CO2 separation by ionic liquids: Theoretical study on the mechanism

To promote the development of ionic liquid (IL) immobilized sorbents and supported IL membranes (SILMs) for CO₂ separation, the kinetics of CO₂ absorption/desorption in IL immobilized sorbents was studied using a novel method based on nonequilibrium thermodynamics. It shows that the apparent chemical‐potential‐based mass‐transfer coefficients of CO₂ were in three regions with three‐order difference in magnitude for the IL‐film thicknesses in microscale, 100 nm‐scale, and 10 nm‐scale. Using a diffusion‐reaction theory, it is found that by tailoring the IL‐film thickness from microscale to nanoscale, the process was altered from diffusion‐control to reaction‐control, revealing the inherent mechanism for the dramatic rate enhancement. The extension to SILMs shows that the significant improvement of CO₂ flux can be obtained theoretically for the membranes with nanoscale IL‐films, which makes it feasible to implement CO₂ separation by ILs with low investment cost. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4437–4444, 2015     

Electrochemical properties of novel ionic liquids for electric double layer capacitor applications

An aliphatic quaternary ammonium salt which has a methoxyethyl group on the nitrogen atom formed an ionic liquid (room temperature molten salt) when combined with the tetrafluoroborate (BF₄⁻) and bis(trifluoromethylsulfonyl)imide [TFSI; (CF₃SO₂)₂N⁻] anions. The limiting oxidation and reduction potentials, specific conductivity, and some other physicochemical properties of the novel ionic liquids, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate (DEME-BF₄) and DEME-TFSI have been evaluated and compared with those of 1-ethyl-3-methylimidazolium tetrafluoroborate. DEME-BF₄ is a practically useful ionic liquid for electrochemical capacitors as it has a quite wide potential window (6.0 V) and high ionic conductivity (4.8 mS cm⁻¹ at 25 °C). We prepared an electric double layer capacitor (EDLC) composed of a pair of activated carbon electrodes and DEME-BF₄ as the electrolyte. This EDLC (working voltage ∼2.5 V) has both, a higher capacity above room temperature and a better charge-discharge cycle durability at 100 °C when compared to a conventional EDLC using an organic liquid electrolyte such as a tetraethylammonium tetrafluoroborate in propylene carbonate.     

Crown ether complex cation ionic liquids: synthesis and catalytic applications for the synthesis of tetrahydro-4H-chromene and 1,4-dihydropyridine derivatives

A series of crown ether complex cation ionic liquids (CECILs) are synthesized by crown ethers chelated with sodium benzenesulfonates, and used as a green and environmental catalyst, for the synthesis of tetrahydro-4H-chromene and 1,4-dihydropyridine derivatives by three-component reactions of aromatic aldehydes and malononitrile with cyclic β-dicarbonyls or cyclic β-enaminoketones respectively, in H₂O/EtOH (1:1), at the reflux condition. CECILs, as a green and environmental catalyst, can be easily obtained and are stable. Furthermore, high conversions, short reaction times, and cleaner reaction profiles are some of the advantages of this method.