离子液体捕集二氧化碳非平衡热力学研究方法学探讨

介绍了应用非平衡热力学研究离子液体捕集二氧化碳（CO2）动力学的思路，分析了其成功应用需解决三大关键科学难题，即可靠的热力学模型，界面传递速率描述以及准确的通量数据．其中，准确通量数据的获得需要可靠的实验动力学数据和离子液体捕集CO2过程传递面积的有效考察．在此基础上系统地总结了该三大关键科学问题最新的研究进展和分析后续开展的工作，并对离子液体捕集二氧化碳非平衡热力学研究提出展望．     

离子液体捕集CO2

CO₂是导致温室效应的最主要成分,因此碳捕集技术的研究受到学术界和产业界的高度重视。离子液体具有不挥发、不燃烧、热稳定性好、溶解能力强、结构和性质可调节并可循环使用等特性,在CO₂的吸收/分离领域展现了广阔的应用前景。本文系统地综述了近年来常规离子液体、功能化离子液体、支撑离子液体膜、聚合离子液体以及离子液体与分子溶剂的混合物在捕集CO₂方面的研究进展;讨论了离子液体的阳离子结构、阴离子类型、烷基链长度、阴/阳离子的氟化程度和功能化、离子液体的负载作用和聚合效应以及体系的温度和压力对CO₂选择性捕集性能的影响;分析了可能的捕集机理以及各种捕集方法的优点和缺点;提出了目前需要进一步研究的若干重要问题,并对其发展前景进行了展望。     

以离子液体为介质的H_2S捕集与转化研究进展

从能源气中脱除硫化氢(H_2S)是能源化工的基础工艺,具有重要的科学和现实意义.离子液体是一类在室温附近呈液态的有机熔融盐,可用作捕集H_2S的新型介质.综合国内外学者和本课题组在该领域内的多年研究积累,本文介绍了H_2S在离子液体中的捕集和转化研究进展,讨论了捕集与转化流程工艺,并分析了当前离子液体用于H_2S捕集与转化的发展趋势.     

离子液体的制备及应用*

离子液体由于具有独特的物理化学性质而成为一种新型的绿色溶剂,近年来成为国际上研究的前沿和热点。它为开发新型绿色工艺、实现传统重污染、高能耗工业过程的升级换代提供了新机遇。本文介绍了离子液体的合成与制备方法,以及离子液体在CO2捕集分离及转化利用、电解/电镀铝、SO2吸收、废水处理以及废旧塑料降解循环利用中的应用,展望了离子液体的发展前景。     

氨基酸离子液体水溶液吸收及解吸二氧化碳机理

氨基酸离子液体是近年来开发的一种新型高效的CO2吸收剂,但其水溶液捕集CO2的机理无明确的论述,普遍借鉴传统有机胺吸收CO2的Zwitterion机理来解释.本文以四甲基铵甘氨酸离子液体为研究对象,采用核磁共振碳谱技术,分析其水溶液捕集CO2过程的产物.与传统有机胺吸收CO2相比,该过程更为复杂,甘氨酸阴离子上的氨基先与CO2反应生成氨基甲酸酯,随着吸收剂的损耗,CO2水合反应增强,氨基甲酸酯水解生成甘氨酸和HCO-3,吸收饱和时CO2的存在形态为HCO3和微量氨基甲酸酯.再生过程则是吸收的逆过程,饱和溶液中的HCO-3先热分解释放CO2,并消耗水中的H+,促使甘氨酸解离为甘氨酸阴离子;部分HCO-3与甘氨酸阴离子反应生成氨基甲酸酯,随后氨基甲酸酯受热分解,释放CO2,溶液得以再生.     

咪唑基离子液体固定分离CO2的研究进展

以咪唑基离子液体为代表,综述了近期普通咪唑基离子液体、功能咪唑基离子液体、支撑咪唑基离子液体和聚合咪唑基离子液体在分离固定CO2方面的研究进展,说明了各类咪唑基离子液体分离固定CO2的可行性及优缺点,并总结了离子液体固定CO2的影响因素和分离机制.     

基于离子液体固定二氧化碳的研究进展

综述了不同种类离子液体吸收固定CO2的研究进展,从离子液体的结构和分子模拟结果探讨了离子液体吸收CO2的机理及特征,展望了功能化离子液体在固定CO2方面的应用前景并分析了其在工业应用中存在的问题.     

离子液体支撑液膜分离CO2

支撑液膜是一种在湿法冶金、生物技术以及气体分离等多个领域都有应用的重要膜分离技术。本文回顾了支撑液膜技术分离CO2的研究进展,按照液膜相的不同,分类介绍了常规载体支撑液膜和离子液体支撑液膜,指出了常规载体支撑液膜分离CO2的局限性,重点介绍了离子液体支撑液膜分离CO2的发展,分析了气体在离子液体支撑液膜中的传质机理以及常规离子液体结构、含量和支撑膜材料等对分离效果的影响;讨论了离子液体的功能化方法以及功能化离子液体支撑液膜分离CO2的渗透率、选择性和液膜稳定性;介绍了两种新的离子液体支撑液膜改进方法:聚离子液体膜与凝胶化离子液体支撑液膜。最后指出了今后用于CO2分离的离子液体支撑液膜的发展方向。     

离子液体吸收分离SO2

离子液体具有极低的挥发性、良好的热稳定性和化学稳定性以及结构性质可调等特点,被认为是一种环境友好的溶剂。由于其结构性质可调,可以设计合成出对SO₂有较高溶解能力和选择性的离子液体,在SO₂的吸收和分离领域得到了研究者的青睐。本文综述了各种用于分离捕集烟气和混合气体中SO₂的离子液体,介绍了它们的结构特点、吸收特性和强化方法,探讨了离子液体脱硫的相关机理,最后对离子液体吸收分离SO₂中存在的问题、发展方向和应用前景进行了论述。     

表面活性剂修饰对MCM-41负载离子液体吸附CO2影响的研究

以表面活性剂修饰的MCM-41为载体,采用浸渍法制备了负载离子液体[NH2p-mim][PF6]的二氧化碳吸附剂,考察了表面活性剂对离子液体在MCM-41上分散的影响以及所导致的CO2吸附性能的变化.利用红外光谱(FT-IR),X-射线衍射(XRD),高分辨透射电子显微镜(HRTEM),热重分析(TG)技术对所合成的负载型离子液体吸附剂进行了表征研究,并与其吸附CO2的性能变化、离子液体与表面活性剂相互作用方式等因素进行了关联.结果表明:MCM-41负载离子液体后对CO2的吸附性能略有提高,而经表面活性剂修饰的MCM-41负载离子液体后,对CO2的吸附容量较载体本身提高了2.5倍.这一方面是因为表面活性剂胶束改善了MCM-41上离子液体的分散性,另一方面是表面活性剂胶束对离子液体分子上电荷分布的影响,导致离子液体内部阴阳离子之间的相互作用减弱,从而引起离子液体中-NH2上N原子电子云密度增大,使其与CO2作用更容易.CO2在经表面活性剂修饰后的MCM-41负载离子液体[NH2p-mim][PF6]吸附剂上的吸附受扩散控制,其吸附-脱附CO2所需能量较小,经过5次吸附-脱附循环后,其吸附性能仍保持稳定.热重分析结果表明,经表面活性剂修饰后的MCM-41负载离子液体吸附剂在100℃下氮气气氛再生时不会发生性质改变.     

Ionic-Liquid-Based Nanofluids and Their Heat-Transfer Applications: A Comprehensive Review

Due to the improved thermophysical characteristics of ionic liquids (ILs), such as their strong ionic conductivity, negligible vapor pressure, and thermal stability at high temperatures, they are being looked at viable contender for future heat transfer fluids. Additionally, the dispersing nanoparticles can further improve the thermophysical characteristics and thermal performance of ionic liquids, which is one of the emerging research interests to increase the heat transfer rates of the thermal devices. The latest investigations about the utilization of ionic liquid nanofluids as a heat transfer fluid is summarized in this work. These summaries are broken down into three types: (a) the thermophysical parameters including thermal conductivity, viscosity, density, and specific heat of ionic liquids (base fluids), (b) the thermophysical properties like thermal conductivity, viscosity, density, and viscosity of ionic liquids based nanofluids (IL nanofluids), and (iii) utilization of IL nanofluids as a heat transfer fluid in the thermal devices. The techniques for measuring the thermophysical characteristics and the synthesis of IL nanofluids are also covered. The suggestions for potential future research directions for IL nanofluids are summarized.     

壳聚糖在4种咪唑型离子液体中溶解性的研究

研究、比较了壳聚糖在4种咪唑型离子液体氯化1-丁基-3-甲基咪唑([BMIM]Cl)、1-丁基-3-甲基咪唑醋酸盐([ BMIM] Ac)、1-乙基-3-甲基咪唑醋酸盐([EMIM] Ac)和氯化1-烯丙基-3-甲基咪唑([AMIM] Cl)中的溶解性,提出了可能的溶解机理,并利用红外光谱(FTIR)、热重分析(TGA...     

1-烷基-3-甲基咪唑硫酸氢盐系列离子液体的热力学性质

在293.15~343.15 K温度范围内,用MYX-1密度计测定了系列离子液体 1-丁基-3-甲基咪唑硫酸氢盐[C4mim]HSO4 (1-butyl-3-methylimdazolium hydrosulfate)、1-己基-3-甲基咪唑硫酸氢盐[C6mim]HSO4 (1-hexyl-3-methylimdazolium hydrosulfate)、1-辛基-3-甲基咪唑硫酸氢盐[C8mim]HSO4 (1-octyl-3-methylimdazolium hydrosulfate)、1-癸基-3-甲基咪唑硫酸氢盐[C10mim]HSO4 (1-decyl-3-methylimdazolium hydrosulfate)的密度。利用不同温度下的密度值计算得出了离子液体的热膨胀系数及分子体积。利用Glasser经验方程计算了离子液体的标准熵和晶格能,并进一步对其热力学性质进行了讨论。     

Local structures in ionic liquids probed and characterized by microscopic thermal diffusion monitored with picosecond time-resolved Raman spectroscopy

Vibrational cooling rate of the first excited singlet (S(1)) state of trans-stilbene and bulk thermal diffusivity are measured for seven room temperature ionic liquids, C(2)mimTf(2)N, C(4)mimTf(2)N, C(4)mimPF(6), C(5)mimTf(2)N, C(6)mimTf(2)N, C(8)mimTf(2)N, and bmpyTf(2)N. Vibrational cooling rate measured with picosecond time-resolved Raman spectroscopy reflects solute-solvent and solvent-solvent energy transfer in a microscopic solvent environment. Thermal diffusivity measured with the transient grating method indicates macroscopic heat conduction capability. Vibrational cooling rate of S(1) trans-stilbene is known to have a good correlation with bulk thermal diffusivity in ordinary molecular liquids. In the seven ionic liquids studied, however, vibrational cooling rate shows no correlation with thermal diffusivity; the observed rates are similar (0.082 to 0.12 ps(-1) in the seven ionic liquids and 0.08 to 0.14 ps(-1) in molecular liquids) despite large differences in thermal diffusivity (5.4-7.5 × 10(-8) m(2) s(-1) in ionic liquids and 8.0-10 × 10(-8) m(2) s(-1) in molecular liquids). This finding is consistent with our working hypothesis that there are local structures characteristically formed in ionic liquids. Vibrational cooling rate is determined by energy transfer among solvent ions in a local structure, while macroscopic thermal diffusion is controlled by heat transfer over boundaries of local structures. By using "local" thermal diffusivity, we are able to simulate the vibrational cooling kinetics observed in ionic liquids with a model assuming thermal diffusion in continuous media. The lower limit of the size of local structure is estimated with vibrational cooling process observed with and without the excess energy. A quantitative discussion with a numerical simulation shows that the diameter of local structure is larger than 10 nm. If we combine this lower limit, 10 nm, with the upper limit, 100 nm, which is estimated from the transparency (no light scattering) of ionic liquids, an order of magnitude estimate of local structure is obtained as 10 nm < L < 100 nm, where L is the length or the diameter of the domain of local structure.     

Thermal Analysis of Binary Mixtures of Imidazolium,Pyridinium, Pyrrolidinium,and Piperidinium Ionic Liquids

Ionic liquids (ILs) are being widely studied due to their unique properties, which make them potential candidates for conventional solvents. To study whether binary mixtures of pure ionic liquids provide a viable alternative to pure ionic liquids for different applications, in this work, the thermal analysis and molar heat capacities of five equimolar binary mixtures of ionic liquids based on imidazolium, pyridinium, pyrrolidinium, and piperidinium cations with dicyanamide, trifluoromethanesulfonate, and bis(trifluoromethylsulfonyl)imide anions have been performed. Furthermore, two pure ionic liquids based on piperidinium cation have been thermally characterized and the heat capacity of one of them has been measured. The determination and evaluation of both the transition temperatures and the molar heat capacities was carried out using differential scanning calorimetry (DSC). It was observed that the thermal behavior of the mixtures was completely different than the thermal behavior of the pure ionic liquids present, while the molar heat capacities of the binary mixtures were very similar to the value of the average of molar heat capacities of the two pure ionic liquids.     

Synthesis,Characterization, Thermal Analyses,and Spectroscopic Properties of Novel Naphthyl-Functionalized Imidazolium Ionic Liquids

A series of novel ionic liquids based on naphthyl-functionalized imidazolium cation have been prepared. Their structure was characterized by NMR. The thermal stabilities of the prepared liquids were studied by thermal gravimetric analysis. The new ionic liquids containing NTf^-₂ anion display significantly higher thermal stabilities (>400°C). Anion exchange to PF^-₆, BF^-₄, and Br^– decreases the thermal stabilities of such ionic liquids. Fluorescence and UV–Vis absorption spectroscopy were used to study the spectroscopic properties of the ionic liquids. Compared with common ionic liquids, the described ionic liquids provide robust fluorescence properties and remarkably increased UV–Vis absorption. This research may enrich the field of functionalized ionic liquids and provide a platform for extension of ionic liquid applications.     

Physical and electrochemical properties of N-alkyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ionic liquids: PY13FSI and PY14FSI

Two ionic liquids based upon N-alkyl-N-methylpyrrolidinium cations (PY(1R)(+)) (R=3 for propyl or 4 for butyl) and the bis(fluorosulfonyl)imide (FSI(-)), N(SO2F)2(-), anion have been extensively characterized. The ionic conductivity and viscosity of these materials are found to be among the highest and lowest, respectively, reported for aprotic ionic liquids. Both ionic liquids crystallize readily on cooling and undergo several solid-solid phase transitions on heating prior to melting. PY13FSI and PY14FSI are found to melt at -9 and -18 degrees C, respectively. The thermal stability of PY13FSI and PY14FSI is notably lower than for the analogous salts with the bis(trifluoromethanesulfonyl)imide (TFSI(-)), N(SO2CF3)2(-), anion. Both ionic liquids have a relatively wide electrochemical stability window of approximately 5 V.     

负载型氨基功能化离子液体吸附CO2性能差异研究

以Al₂O₃、SiO₂和活性炭为载体,采用浸渍法制备了负载型离子液体（[NH₂p-mim]X:X= Br-,PF₆-,BF₄-,NTf₂-）CO₂吸附剂,利用红外光谱（FT-IR）、元素分析(EA)、热重差热分析（TG-DTA）等技术对负载型离子     

New ionic liquids with tris(perfluoroalkyl)trifluorophosphate (FAP) anions

The synthesis of new ionic liquids with tris(perfluoroalkyl)trifluorophosphate (FAP) anions is described. The physico-chemical properties (conductivity, viscosity, electrochemical and thermal stability) of this new generation of ionic liquids (molten salts) are discussed. FAP-ionic liquids show an excellent hydrolytic stability, low viscosity and high electrochemical and thermal stability that makes them attractive for use in electrochemical devices and as a new media for application in modern technologies and chemical synthesis.     

Synthesis and characterization of new pyrrolidinium based protic ionic liquids. Good and superionic liquids

New pyrrolidinium-cation-based protic acid ionic liquids (PILs) were prepared through a simple and atom-economic neutralization reactions between pyrrolidine and Br?nsted acids, HX, where X is NO 3 (-), HSO 4 (-), HCOO (-), CH 3COO (-) or CF 3COO (-) and CH 3(CH 2) 6COO (-). The thermal properties, densities, electrochemical windows, temperature dependency of dynamic viscosity and ionic conductivity were measured for these PILs. All protonated pyrrolidinium salts studied here were liquid at room temperature and possess a high ionic conductivity (up to 56 mS cm (-1)) at room temperature. Pyrrolidinium based PILs have a relatively low cost, a low toxicity and exhibit a large electrochemical window as compared to other protic ionic liquids (up 3 V). Obtained results allow us to classify them according to a classical Walden diagram and to determinate their "Fragility". Pyrrolidinium based PILs are good or superionic liquids and shows extremely fragility. They have wide applicable perspectives for fuel cell devices, thermal transfer fluids, and acid-catalyzed reaction media as replacements of conventional inorganic acids.