纤维素在离子液体中的溶解特性研究

测定了纤维素在不同结构的离子液体——1-烯丙基-3-甲基咪唑氯化物([AMIM]Cl)和1-丁基-3-甲基咪唑氯化物([BMIM]Cl)中的溶解度和溶解速率。结果发现:相同条件下,纤维素在[AMIM]Cl中具有较大的溶解度和较快的溶解速率;随着纤维素聚合度的增大,相同条件下,纤维素在离子液体中的溶解度降低。进一步通过WXRD、FT-IR、13C NMR和黏度法分析了溶解前后纤维素的化学结构、结晶结构和聚合度,结果表明:纤维素在离子液体中的溶解属于直接溶解,纤维素经离子液体溶解和再生后,晶型由纤维素I转变为纤维素II;溶解时间和温度对再生纤维素的聚合度有较大的影响,随着溶解时间的延长和溶解温度的提高,再生纤维素聚合度降低。     

Exploring the Absorption Mechanisms of Imidazolium-Based Ionic Liquids to Epigallocatechin Gallate

Imidazolium-based ionic liquids are wildly used in natural product adsorption and purification. In this work, one typical polymeric ionic liquid (PIL) was synthesized by using L-proline as the anion, which exhibited excellent adsorption capacity toward tea polyphenol epigallocatechin gallate (EGCG). The adsorption conditions were optimized with the response surface method (RSM). Under the optimum conditions, the adsorption capacity of the PIL for EGCG can reach as high as 552 mg/g. Dynamics and isothermal research shows that the adsorption process of EGCG by the PIL particularly meets the quasi-second-order kinetic equation and monolayer adsorption mechanism. According to thermodynamic parameter analysis, the adsorption process is endothermic and spontaneous. The results of theoretical calculation by molecular docking also demonstrated the interaction mechanisms between EGCG and the ionic liquid. Considering the wide application of imidazolium-based ionic liquids in component adsorption and purification, the present study can not only be extended to other similar experimental mechanism validation, but also be representative for guiding the synthesis of PIL and optimization of adsorption conditions.     

New Ammonium- and 1,2,4-Triazolium-Based Ionic Liquids for Wood Preservation

Biological activity of new potential wood preservatives—ammonium- and triazolium-based ionic liquids—was determined employing screening agar-plate, agar-block, and perlite-block methods. Experiments were carried out on Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.) wood. This study examined the effect of the ionic liquid structure on anti-fungal efficacy, depth of penetration, and fixation in wood. It was stated that the fungicidal value of new ammonium compounds depended, above all, upon the cation structure; for Coniophora puteana, it ranged from 2.7 kg m^?3 to 4.6 kg m^?3. These compounds effectively protected Scots pine wood against the action of mold fungi. Ammonium ionic liquids with a nitrite anion were characterized by strong fungitoxic properties, stronger than ammonium nitrates. The application in the amount of 15 g m^?2 caused an insignificant growth of mold fungi on the surface of Scots pine wood. For the mixture of 7.5% tebuconazole and 7.5% propiconazole dissolved in ionic liquids, the synergistic effect against mold fungi at the application of 15 g m^?2 was found. Dissolving tebuconazole in didecyldimethylammonium nitrate repeatedly lowered the fungicidal value against brown-rot fungi, as well as increased penetration of the ionic liquids in wood. This was associated with reduced viscosity of this ionic liquid caused by the addition of 1,2,4-triazole derivatives. Quaternary derivatives of 1,2,4-triazoles showed very high activity against blue stain and wood-decaying fungi. Additionally, most of the test compounds were well-fixed in Scots pine wood. The spectral study in infrared confirmed that nitrite, nitrate anions, and didecyldimethylammonium cation were retained in the treated wood.     

离子液体在溶解方面的研究进展

离子液体作为一种新型的“绿色溶剂”,广泛应用于化学反应、萃取分离等化工过程。介绍了绿色溶剂——离子液体发展状况,详细讨论了离子液体在溶解方面的研究进展,包括离子液体在萃取分离方面的研究、离子液体作为反应过程中的溶剂以及离子液体作为高分子溶剂的研究。     

木质素在离子液体中溶解及改性的研究进展

木质素是自然界中含量仅次于纤维素、唯一含有苯环结构的可再生生物质资源,对其进行有效的开发利用具有较高的经济价值和社会价值。离子液体作为一种新型绿色溶剂,在木质纤维素溶解方面展现了良好性能,本文粗略地概述了木质素的基本结构和性质,对木质素在离子液体中的溶解及改性等方面的研究进行了总结和综述,并在离子液体在木质素溶解降解方面应用研究的发展前景进行了分析讨论。     

咪唑类离子液体及其在生物催化中的应用

咪唑类离子液体的合成,概括了离子液体中生物催化反应的特点,重点介绍咪唑类离子液体在蛋白酶催化的反应、脂肪酶催化的反应、氧化还原酶催化的反应以及其它酶催化的反应中的应用。     

离子液体中金属的电沉积

与普通有机溶剂相比,室温离子液体具有很宽的电化学窗口,优良的导电性,不挥发,热稳定性较高等优点.离子液体作为新一代绿色溶剂正日益受到重视.将离子液体分为AlCl3型离子液体和非AlCl3型离子液体两类,分别评述了在这两类离子液体中金属电沉积的研究进展.     

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。     

离子液体的合成及应用进展

介绍了离子液体的国内外发展现状,总结了离子液体的特性和制备方法及其在有机反应、电化学、无机纳米材料方面的应用.     

离子液体回收的研究进展

离子液体作为一种绿色溶剂可以有效地解决目前存在的能源和环境问题。由于离子液体相对于其它有机溶剂具较好的化学稳定性,使其在众多的研究领域受到越来越多的关注。但是离子液体存在着合成成本较高、回收难度较大等技术瓶颈问题,因而阻碍了它的广泛应用。而安全、有效地回收离子液体能够解决这一难点。离子液体的回收方法有减压蒸馏、膜分离、盐析、液液萃取等。离子液体的有效回收可以促进化学合成、纤维素提取等领域的快速发展。     

Dielectric Study of Tetraalkylammonium and Tetraalkylphosphonium Levulinate Ionic Liquids

Broadband dielectric spectroscopy in a broad temperature range was employed to study ionic conductivity and dynamics in tetraalkylammonium- and tetraalkylphosphonium-based ionic liquids (ILs) having levulinate as a common anion. Combining data for ionic conductivity with data obtained for viscosity in a Walden plot, we show that ionic conductivity is controlled by viscosity while a strong association of ions takes place. Higher values for ionic conductivities in a broad temperature range were found for the tetraalkylphosphonium-based IL compared to its ammonium homolog in accordance with its lower viscosity. Levulinate used in the present study as anion was found to interact and associate stronger with the cations forming ion-pairs or other complexes compared to the NTf₂ anion studied in literature. In order to analyze dielectric data, different fitting approaches were employed. The original random barrier model cannot well describe the conductivity especially at the higher frequencies region. In electric modulus representation, two overlapping mechanisms contribute to the broad low frequencies peak. The slower process is related to the conduction mechanism and the faster to the main polarization process of the complex dielectric permittivity representation. The correlation of the characteristic time scales of the previous relaxation processes was discussed in terms of ionic interactions.     

离子液体在气体吸附中的研究进展

综述了气体在离子液体中的溶解性能、影响因素及其传质机理;介绍了CO2、SO2等气体在离子液体中的吸附研究进展;总结了离子液体中气体分离、分析及有气体参与的化学反应等领域的研究现状,并展望了离子液体在气体吸附方面的应用前景。     

离子液体的合成

离子液体作为一类新型的环境友好的。绿色溶剂”,具有很多独特的性质,在很多领域有着诱人的应用前景。本文主要介绍了以N,N’-二烷基咪唑阳离子,N-烷基吡啶阳离子与含氟阴离子,氯酸铝阴离子等形成的室温离子液体的合成方法。     

绿色溶剂离子液体在化学反应中的应用

离子液体用作化学反应的溶剂，对提高化学反应速率、选择性，或实现催化剂的循环利用及产物分离都具有明显的优势，而且对许多化学反应，离子液体还具有催化功能。这对于开发新的化学工艺，实现绿色化学过程具有重要的意义。本文主要介绍离子液体在化学反应中的应用最新进展及其工业化前景。     

季铵盐型离子液体合成与应用的研究进展

总结了离子液体的通用合成方法,归纳了季铵盐型离子液体在Friedel-Crafts烷基化反应、Heck反应、酯化反应和电化学及萃取等领域的应用。     

离子液体及其应用研究新进展(待续)

叙述了离子液体的组成、分类、性质、制备和纯化.离子液体具有熔点低、蒸气压小、酸性可调及良好的溶解度、粘度等特点,作为环境友好和"可设计性"溶剂正在引起越来越多的重视.     

纤维素在离子液体中的降解研究进展

随着化石能源的日益短缺和环境污染问题的日趋严重,可再生的生物质资源引起了人们的广泛关注。离子液体作为一种新型的绿色溶剂,越来越多的被应用到木质纤维素的溶解和降解中。从无机金属氯盐、酸催化和酶催化三个方面简要介绍了近几年来纤维素在离子液体中的降解转化过程,指出了离子液体自身存在的缺陷和应用过程中存在的问题,提出了未来研究工作的重点和对关键问题的解决方法。     

离子液体的合成与应用

叙述了离子液体的类型和特点,阐明了离子液体是一种安全绿色环保的液体,是当代化学的研究热点之一。由N-甲基咪唑和溴代正丁烷合成了中间体溴化1-正丁基-3-甲基咪唑,又利用中间体进一步合成了离子液体1-正丁基-3-甲基咪唑四氟硼酸盐和1-正丁基-3甲基六氟磷酸盐,并分别对这三种离子液体做了红外光谱分析。简单绍了离子液体在生物技术中物质的分离和纯化。介绍了离子液体在碱金属和碱土金属、稀土金属和锕系等金属离子萃取方面的应用。表明离子液体有着广阔的发展前景。     

手性功能化离子液体的合成进展

手性离子液体作为功能化离子液体的一种,综合了离子液体与手性物质两方面的特性。不仅具有手性特征,而且几乎无蒸气压,无可燃性,具有很高的热力学和化学稳定性,电导率高,可以循环使用,对无机和有机物有良好的溶解性、稳定性等。手性离子液体可以作为手性溶剂,催化剂载体或手性诱导剂,应用于手性合成、手性分离和手性催化等领域。本文综述了近些年来手性离子液体合成的最新进展,结构上按阴、阳离子分类,同一离子类型中按物质种类分类。同时介绍了一些新的合成技术。最后对手性离子液体可能的发展趋势和以后的研究方向进行了展望。     

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。