离子液体的合成及功能性离子液体的研发进展

离子液体作为可替代现有挥发性有机溶剂的新型绿色溶剂引起人们的广泛关注。离子液体是指在室温或接近室温下呈液态的全部由离子组成的物质,与固态物质相比较,它是液态的;与传统的液态物质相比较,它是离子的。由于离子液体不挥发、不可燃、导电性强、黏度低、热容大、蒸气压小、性质稳定,对许多无机盐和有机物有良好的溶解性,在分离过程和化学反应领域显示出良好的应用前景。     

离子色谱法检测稀土中阴离子

稀土不仅是重要的战略资源,同时在工业、农业、医药方面起着重要的作用。研究表明,稀土原料中的一些掺杂离子,会影响稀土材料的性质,进而影响合成过程中的稀土离子的扩散,导致稀土材料合成的物质结构和性能发生变异。下面主要介绍一下如何用离子色谱法检测稀土中微量的杂质离子。     

普通离子液体和功能化离子液体的合成研究进展

离子液体是在室温下为液体、具有离子特性的新型绿色溶剂,作为一类环境友好型的反应介质,在诸多领域有其独特的性质.综述了普通离子液体和功能化离子液体的合成研究进展,并对其前景进行了展望.     

绿色溶剂离子液体的性质和应用研究进展

离子液体即在室温或近室温温度下呈液态的完全由离子构成的物质。作为一种绿色溶剂,其具有熔点低、蒸气压小、电化学窗口大、酸性可调及良好的溶解度、粘度和密度等特点。离子液体由于其优良性质在分离、有机合成及催化反应等领域被广泛应用,其对环境友好使得在工业上的应用前景良好。     

离子液体降解的研究进展

离子液体因具有蒸汽压低、稳定性好、溶解范围广等优点,被认为是21世纪环境友好的绿色溶剂和催化剂之一。离子液体因其独特的理化性质,已经被广泛地应用到化学反应、物质的分离和纯化过程、电化学等各个领域。近几年,随着研究的不断深入,离子液体潜在的毒性、生物降解性已经引起许多研究者的高度重视。本文就离子液体的毒性及其降解方法的研究进展进行了系统的综述,并对未来的发展进行了展望,为进一步研究提供参考。     

六氟锑酸盐离子液体的研究进展

六氟锑酸盐离子液体具有常规离子液体的特性,如低蒸汽压、不挥发、物质溶解性好等,不仅可以作为溶剂,还可以通过调配阴阳离子比例或离子交换得到路易斯酸催化剂,在多种类型反应中得到应用。主要对近年来六氟锑酸盐离子液体的合成、结构、性质及其在反应中的应用进行综述。     

混合离子的鉴定

对常见未知物的鉴别和未知离子的鉴定可作为无机化学实验中的一个开放型设计实验的课题。本课题的实践过程,均由设计者自行设计与实验。在设计与实验中,设计者根据所学的元素化学知识,进行常见物质及离子的鉴别、鉴定。     

离子液体的研究进展

离子液体作为一种新型的绿色物质,具有众多优异的物理化学性质,可通过合适的分子设计调节阴阳离子合成特殊性能离子液体,具有广阔的应用前景。在此,对离子液体作为溶剂和电池电解质两个方面的研究进展做一简要综述,同时对离子液体应用研究中存在的问题和今后的研究方向作一简单探讨。     

离子液体及其在电化学中的应用

离子液体即在室温或接近室温下呈液态的完全由离子构成的物质，作为环境友好和“可设计性”溶剂正在引起越来越多的重视。它具有熔点低、蒸汽压小、酸性可调及良好的溶解度、粘度和密度等特点。综述了离子液体的组成、分类、性质、制备和纯化，就离子液体在电池技术、电合成、电沉积、电容器等电化学方面的应用和研究进展加以阐述，并对该领域的研究前景作了展望。     

离子液体中酯化反应的研究进展

离子液体被誉为"绿色"介质,由于具备液程宽、良好的热稳定和化学稳定性,与许多小分子物质杰出的相溶性、高的极性和导电性、再循环能力强和可忽略的蒸气压等众多优良性质,被广泛应用在酯化反应中.对以离子液体作为反应介质时进行的酶催化酯化反应、纤维素改性、生物柴油转化等反应的研究进展进行了介绍.     

离子液体在萃取中的应用研究

离子液体具有特殊的物理化学性质,通过选择不同的阳离子和阴离子改变离子液体的物理化学性质,因此离子液体可以取代传统的有机分子溶剂应用于不同的分离过程.本文综述离子液体萃取金属离子、有机化合物、生物分子,脱硫,脱氮及气体分离等的最近研究进展.     

Nutrient concentration in soil water extracts and soybean nutrition in response to lime and gypsum applications to an acid Oxisol under no-till system

No-till system (NTS) occupies 20 million hectares with grain crops in Brazil. However, calcium deficiency and aluminum toxicity can limit crop yields in many soils, and liming, associated to gypsum application, is an option for improving soil management. The objective of this study was to evaluate the effects of lime and gypsum application on the composition of soil water extracts of a clayey Rhodic Hapludox, cultivated with soybean under NTS. The experiment had a randomized complete block design with split-plots. The plots consisted of lime treatments (either a single rate of 4.5 t ha⁻¹ or three annual rates of 1.5 t ha⁻¹) surface-applied or incorporated at 0.2 m depth. The subplots received surface applications of gypsum (3, 6 and 9 t ha⁻¹). Liming increased total calcium and magnesium concentrations and the magnesium free Form activity (aMg²⁺) in the water extracts. The effect of liming on Mg was observed at deeper layers of the soil profile. Gypsum increased total concentration and free forms activities at calcium (aCa²⁺) and sulfate, but decreased to magnesium in the 0.05–0.2 m soil layer. Part of Mg lost from these upper layers probably contributed to increased Mg in the subsoil (0.4–0.8 m). Free forms activities at the aluminum, calcium, magnesium and sulfate were lower than the total concentrations, mainly for aluminum. Ca and Mg concentrations in soybean leaf tissue were positively correlated to the aCa²⁺ and aMg²⁺ in the soil water extract. Soybean grain yield was negatively correlated to both Mn total concentration and activity (free form) in the soil water extract, but it was positively correlated to sulfate (total concentration and free form activity) in the subsoil layer and to the Ca total concentration in the upper layer (0–0.05 m). It is concluded that lime and gypsum ameliorate soybean grain yield under NTS.     

Block copolymer/ionic liquid films: The effect of ionic liquid composition on morphology and ion conduction

The effect of morphology on ion transport in ionic liquid-based solid-state films was investigated. In this study, mixtures of a block copolymer, poly(styrene-b-methyl methacrylate) (SbMMA), and an ionic liquid (IL), 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide (EMIm-TFSI), were prepared as clear solid-state films at various IL compositions (0-50 wt%) by solution casting from a volatile co-solvent. The IL was preferentially miscible with the MMA block as evidenced by visual inspection and differential scanning calorimetry. Both equilibrium and non-equilibrium morphologies were identified with X-ray scattering and transmission electron microscopy and the morphology varied with MMA/IL volume fraction. The morphology and microdomain orientation had a significant impact on ionic conductivity. Higher through-plane conductivities were observed in morphologies with a three-dimensionally continuous conducting path (e.g., non-conducting S cylinders) compared to morphologies with a non-continuous conducting path (e.g., lamellae). When the lamellae were oriented in the plane, the through-plane conductivity was significantly lower than the in-plane conductivity, while the conductivity was direction-independent when the morphologies have a continuous conductive path. Also, a significant increase in conductivity was observed with increasing IL content at the glass transition of the conductive (MMA/IL) microdomain. Finally, significantly higher ionic conductivities can be achieved in a block copolymer/IL solid-state film compared to a homopolymer/IL film at the same IL content (wt%), because the non-conductive microdomain excludes IL, which produces a higher local IL concentration in the conductive phase.     

Morphology and deformation behavior of polymer blends made of poly(styrene-co-styrenesulfonic acid) and poly(methyl methacrylate-co-4-vinylpyridine)

The effect of a small amount of ionic groups (interactions) on the morphology and deformation behavior of stoichiometric blends made of poly(styrene-co-styrenesulfonic acid) (SPS) and poly(methyl methacrylate-co-4-vinylpyridine) (MVP) was investigated by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). FTIR data revealed that intermolecular ion-ion interactions were formed between SPS and MVP polymers, arising from proton transfer from sulfonic acid groups to pyridine groups upon blending. TEM observations show that the morphology of the blends changes from macroscopic phase separation to microscopic phase separation, and to miscibility, with increasing ion content of the blends from 0 to 6 mol%. Correspondingly, deformation behavior of the blends changes from crazing only, to curved and branched crazing, and to crazing plus shear deformation. Such changes in deformation mode can be understood as arising from the morphological changes and the increase of ‘effective’ strand density due to the formation of ionic cross-links in the blends.     

Improved ionic conductivity of nitrile rubber/ionic liquid composites

Polymer electrolytes with high ionic conductivity and good elasticity were prepared by mixing nitrile rubber (poly(acrylonitrile-co-butadiene) rubber; NBR) with ionic liquid, N-ethylimidazolium bis(trifluoromethanesulfonyl)imide (EImTFSI). The NBR/EImTFSI composites were obtained as homogeneous and transparent films when the ionic liquid content was less than 60 wt%. Raman spectroscopy suggested the interaction between nitrile group of NBR and TFSI anion. Sample with ionic liquid content of 50 wt% showed the ionic conductivity of 1.2×10⁻⁵ S cm⁻¹ at 30 °C. Addition of lithium salt to this NBR/EImTFSI composite further enhanced the ionic conductivity to about 10⁻⁴ S cm⁻¹ without spoiling mechanical properties. DSC studies showed two glass transition temperatures for composites indicating microphase separation.     

Recent Developments and Applications of Ionic Liquids in Gas Separation Membranes

Flue gas emissions and the harmful effects of these gases urge to separate and capture these unwanted gases. Ionic liquids due to negligible vapor pressure, thermal stability, and wide electrochemical stability have expanded its application in gas separations. A comprehensive overview of the recent developments and applications of ionic liquid membranes (ILMs) for gas separation is given. The three general classifications of ILMs, such as supported ionic liquid membranes (SILMs), ionic liquid polymeric membranes (ILPMs), and ionic liquid mixed‐matrix membranes (ILMMMs) along with their applications, for the separation of various mixed gases systems is discussed in detail. Furthermore, issues, challenges, computational study, and future perspectives for ILMs are also considered.     

离聚体的结构及其影响因素

离聚体中的离子对具有一定的配位结构,由于离子对的聚集作用能形成多重离子对或离子簇结构;离子对含量、离子对的特性、聚合物基质的性质、增塑剂、吸收的水份及热作用等都将影响离聚体的结构.本文对这些内容进行了综述.     

Charge Dynamics and Bending Actuation in Aquivion Membrane Swelled with Ionic Liquids

The actuation strain and speed of ionic electroactive polymer (EAP) actuators are mainly determined by the charge transport through the actuators and excess ion storage near the electrodes. We employ a recently developed theory on ion transport and storage to investigate the charge dynamics of short side chain Aquivion^® (Hyflon^®) membranes with different uptakes of ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-Tf). The results reveal the existence of a critical uptake of ionic liquids above which the membrane exhibits a high ionic conductivity (σ > 5 × 10⁻² mS/cm). Especially, we investigate the charge dynamics under voltages which are in the range for practical device operation (∼1 V and higher). The results show that the ionic conductivity, ionic mobility, and mobile ion concentration do not change with the applied voltage below 1 V (and for σ below 4 V). The results also show that bending actuation of the Aquivion membrane with 40wt% EMI-Tf is much larger than that of Nafion, indicating that the shorter flexible side chains improve the electromechanical coupling between the excess ions and the membrane backbones, while not affecting the actuation speed.     

One-phase preparation of palladium nanoparticles using thiol-functionalized ionic liquid

Thiol-functionalized ionic liquid (TFIL: 1,3-di(2’,3’-dimercaptoacetoxypropyl) imidazolium, 3′’-mercapto1 ″-propanesulfonic acid) as a stabilizer for preparing palladium (Pd) nanoparticles was synthesized. The suggested TFIL was designed to have thiol groups on both cation and anion as well as on symmetrical positions in cation. Transmission electron microscopy (TEM) shows that the average diameter of the palladium nanoparticles was 3.0 nm and that the standard deviation was 0.15 nm. The overall results strongly suggest that this potential TFIL can act as a highly effective stabilizer for the preparation of Pd nanoparticles     

Effect of cation structure on the electrochemical and thermal properties of ion conductive polymers obtained from polymerizable ionic liquids

Several onium cations having vinyl group formed ionic liquids after coupling with bis(trifluoromethanesulfonyl)imide. These monomers were polymerized, and the relation between onium cation structure and properties of thus polymerized ionic liquids was investigated. The polymerized ionic liquid having ethylimiadzolium cation unit showed the highest ionic conductivity of around 10⁻⁴ S cm⁻¹ at 30 °C among the obtained polymers reflecting the lowest glass transition temperature of −59 °C. These polymers were thermally stable and their decomposition temperatures were about 350 °C. The ionic conductivity of the polymerized ionic liquids decreased by both the addition of lithium bis(trifluoromethanesulfonyl)imide and the polymerization in the presence of cross-linker. However, the polymerized ionic liquid having 1-methylpiperidinium cation structure showed good lithium ion transference number of 0.43 at room temperature.