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以环氧氯丙烷为交联剂,采用室温化学交联法制备了聚乙烯醇(PVA)水凝胶,研究了交联温度和交联时间对PVA溶胀性能和力学性能的影响,借助差示扫描量热法(DSC)和扫描电子显微镜(SEM)对PVA水凝胶进行分析表征。结果表明,当交联时间为3d且交联温度为50℃时PVA水凝胶的综合性能最佳。PVA的玻璃化转变温度为-54.50℃,PVA水凝胶中包含有自由水、束缚水和非冷冻水。 相似文献
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离子液体作为一种新型的绿色溶剂和催化剂已引起了化学家们的极大关注.以乙酸钠和环氧氯丙烷为起始原料首先合成了乙酸缩水甘油酯,并优化筛选了乙酸缩水甘油酯的合成条件;再与无机酸质子化的N-甲基咪唑反应,制备了四个N-甲基-N'-(2-羟基-3-乙酰氧基丙基)咪唑盐新型离子液体.采用1H NMR,IR和UV对新型离子液体的结构进行了表征.测定了新型离子液体的电导率及与常用有机溶剂之间的溶解性能.优化筛选试验结果表明,乙酸缩水甘油酯最佳的合成条件为:乙酸钠与环氧氯丙烷的摩尔投料比为1:1.5,甲苯作溶剂,四丁基溴化铵为催化剂,回流反应7h. 相似文献
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《化工进展》2017,(2)
首先以环氧氯丙烷为原料,通过开环聚合得聚环氧氯丙烷(PECH),再通过溴化和氨化等方法得到端氨基的聚环氧氯丙烷,再将其与N-甲基咪唑反应,制备氯化1-氨基聚醚-3-甲基咪唑离子液体([H_2N-PECH-MIM]Cl)催化剂,并利用红外(IR)和核磁(NMR)对其化学结构进行表征,利用热重分析仪(TGA)和凝胶渗透色谱仪(GPC)对其热性能和分子量进行了测试。然后用制备的高分子离子液体[H_2N-PECH-MIM]Cl催化环氧丙烷与二氧化碳合成碳酸丙烯酯,以纯度、转化率、选择性和转化频率为考察指标,研究催化温度、压力、循环使用次数对催化性能的影响,并比较了其与溴化1-乙胺基-3-甲基咪唑离子液体[Ae MIM]Br的催化性能。结果表明,制备的高分子催化剂[H_2N-PECH-MIM]Cl结构正确,产率为71%,其催化性能远远优于小分子离子液体[Ae MIM]Br,可在不用助催化剂的温和条件下即可高效完成催化过程,且循环使用10次基本不影响其催化活性。当催化温度为90℃,压力为1.8MPa,用量为1.0%时,纯度为99.0%,转化率为100%,选择性高达96.9%,转化频率TOF为3848h~(-1)。 相似文献
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Ionic liquid supported liquid membranes have shown high CO2 selective separation performance, but their low pressure resistance greatly limits their industrial applications. From the viewpoint of high cost and complex synthesis of crosslinkers used for crosslinking ILs, preparing IL-based gels by crosslinking diamino protic ionic liquids (PILs) with epichlorohydrin (ECH) was proposed in this work. The feasibility of this conception was confirmed via monitoring dynamical information of reaction system. The effects of protonation, reaction temperature and ECH-to-PIL molar ratio on the conversion of epoxy and chloride groups were systematically investigated. The gel transition property of these crosslinked PILs and the possible crosslinking mechanism were studied. Moreover, CO2 permeation performance in crosslinked ILs was preliminarily tested. 相似文献
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离子液体由于具有不易挥发、结构可调、对CO2有良好的吸收性能等特点而成为当前CO2分离领域的研究热点,但因高黏度和高成本问题而限制了其工业化应用。将离子液体与气体分离膜材料结合,得到的新型分离膜材料兼具离子液体和膜的优势,成为当前离子液体研究领域的趋势之一。针对这一热点问题,综述了离子液体支撑液膜、聚离子液体膜和离子液体共混/杂化膜在CO2分离方面的研究现状和进展,讨论了离子液体结构和含量对膜分离性能、稳定性等的影响。相关研究表明,离子液体共混/杂化膜具有较高的分离性能和稳定性,是一种很有应用前景的CO2分离材料。提出该领域的重点发展方向,即开发新的功能化离子液体共混/杂化膜材料是解决高渗透通量与高稳定性之间矛盾、强化CO2分离性能的有效途径,深入研究离子液体共混/杂化膜的形成机制、气体在膜中的渗透行为以及CO2分离机理。 相似文献
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Suojiang Zhang Yuhuan Chen Fuwei Li Xingmei Lu Wenbin Dai Ryohei Mori 《Catalysis Today》2006,115(1-4):61-69
Ionic liquids (ILs), a kind of novel green media composed entirely of cations and anions, have recently attracted considerable attention due to their unique properties such as non-volatility, tunable polarity, high stability and so on. In this work, the latest progress on the fixation and conversion of carbon dioxide (CO2) using ILs as absorbents, catalysts or promoters has been summarized. The absorption performance of conventional ILs and task-specific ILs was systematically investigated, the conversion of CO2 with epoxides, propargyl alcohols and amines using ILs was critically evaluated, and the significant advantages in the fixation and conversion of CO2 using the ILs were demonstrated compared to the conventional absorbents and the catalytic systems without ILs. This research progress may finally lead to building of an in situ fixation–conversion process of CO2 with ILs. If so, we are near an epoch of the fixation and utilization of CO2, although there is obviously a long way to go for us to achieve such a goal. 相似文献
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Molecular dynamics simulation with an all-atom force field has been carded out on the two binary sys- tems of [bmim][PF6]-CO2 and [bmim][NO3]-CO2 to study the transport properties, volume expansion and micro- structures. It was found that addition of CO2 in the liquid phase can greatly decrease the viscosity of ionic liquids (ILs) and increase their diffusion coefficient obviously. Furthermore, the volume expansion of ionic liquids was found to increase with the increase of the mole fraction of CO2 in the liquid phase but less than 35% for the two simulated systems, which had a significant difference with CO2 expanded organic solvents. The main reason was that there were some void spaces inter and intra the molecules of ionic liquids. Finally, site to site radial distribution functions and corresponding number integrals were investigated and it was found that the change of microstructures of ILs bv addition CO2 had a great influence on the orooerties of ILs. 相似文献
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近百年来,伴随着矿石燃料的大量消耗,CO2的排放量剧增,引发了全球性的生态环境和社会问题。CO2同时也是廉价且可再生的碳资源,可作为生产醇、醚、酸、酯等重要化工品的原料。在众多吸引力十足的CO2利用路线中,作为清洁、可控的反应过程,电化学还原固定CO2技术在温和条件下生产化学品方面具有独特的优势。离子液体以其特有的性质被广泛用于电化学还原CO2过程,本文对目前国内外离子液体介质中电化学还原CO2的研究现状进行了综述,介绍了离子液体介质中电化学还原CO2的主要反应及基本原理;针对离子液体对CO2高效活化和转化等关键科学问题进行深入探讨,提出新型功能化离子液体的应用将成为CO2电化学还原领域的发展方向和热点。 相似文献
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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。 相似文献
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Haiyan Jiang Lu Bai Bingbing Yang Shaojuan Zeng Haifeng Dong Xiangping Zhang 《中国化学工程学报》2022,43(3):169-176
The separation of carbon dioxide (CO2) is of great importance for environment protection and gas resource purification. The ionic liquids (ILs)-based gas separation membrane provides a new chance for efficient CO2 separation, while high permeability and selectivity of membranes is a great challenge. In this study, the influence of two protic ILs with different anion ([TMGH][Im] and [TMGH][PhO]) on the CO2 separation performance of the prepared ILs/Pebax blended membranes were systematically investigated at different temperature. The results showed the CO2 permeability exhibits the rising trend for ILs/Pebax blended membranes with the increment of IL content. Especially, the [TMGH][Im] with low viscosity and high CO2 absorption capacity leads to the blended membranes showing better CO2 permeability and ideal CO2 selectivity than that of membranes with [TMGH][PhO] at high IL content. Besides, with operating temperature increasing, the gas permeability of 20% (mass) [TMGH][Im]/Pebax blended membrane increases due to the decreasing viscosity of IL and the rising chain mobility of polymer. Inversely, the gas selectivity shows decreasing trend because CO2 absorption capacity obviously decreased at higher temperature. 相似文献
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吸收及分离二氧化碳是降低碳排放和应对全球气候变化的主要策略之一,这就必然要求全球科技工作者注重开发具有选择性高效吸收分离二氧化碳的新材料和新路线。作为近20多年来发展的一类代表性的新材料,离子液体(尤其是功能化离子液体)具有独特的物理化学性质,例如几乎没有蒸气压、液态温度范围大、热稳定性和化学稳定性好、电化学窗口宽、不可燃、结构-性质可调控等。这些性质使离子液体在二氧化碳吸收及分离领域受到广泛关注。重点综述了近5年(2015~2019)来功能化离子液体吸收分离二氧化碳的研究进展, 主要内容包括单位点离子液体、多位点离子液体、基于功能化离子液体的混合物、功能化离子液体杂化材料对二氧化碳的吸收分离。同时, 对目前该领域的发展所面临的主要问题和进一步的研究工作进行了分析讨论。 相似文献
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Ammonium-based ionic liquid monomers and their corresponding polymers [poly(ionic liquid)s] are synthesized and characterized for CO2 sorption. The polymers have much higher CO2 sorption capacities than the room-temperature ionic liquids and imidazolium-based poly(ionic liquid)s. For example, P[VBTMA][PF6] with polystyrene backbone has a CO2 sorption capacity of 10.67 mol%. The CO2 sorption is selective over N2 and O2. The effects of cation, backbone, substituent, anion and crosslinking on CO2 sorption are discussed. The sorption mechanism study indicates that CO2 sorption by the poly(ionic liquid)s is a bulk and surface phenomenon. 相似文献
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离子液体(ILs)由于其独特的结构可调性,作为添加剂可有效抑制氨法碳捕集中NH3的逃逸并同时促进CO2的吸收。揭示其吸收NH3和CO2的作用机理对于构建特定的功能型ILs结构具有重要意义。本文采用密度泛函理论(DFT),在B3LYP/6-31'++G(d,p)基组水平下对设计的五种功能型ILs进行了结构优化、频率计算以及原子电荷分析,获得了优化后的结构参数、振动频率以及原子电荷等数据。在此基础上对ILs吸收CO2和NH3进行了相互作用分析。计算结果表明:[HEBim][His]的稳定性最好,经过BSSE校正后的相互作用能为-415.73 kJ·mol-1。通过静电势和电荷分析找到了设计的ILs与气体作用的最佳位点:NH3主要与ILs阳离子的羟基形成 O—H…N型氢键,其中,[HEBim][His]吸收NH3的能力最强,形成的氢键结合能为38.52 kJ·mol-1,具有较强的氢键作用;CO2主要与阴离子中的氨基形成C—N…C型氢键,[HEBim][Ala]吸收CO2的能力最强,形成的氢键结合能为10.15 kJ·mol-1,具有较弱的氢键作用。当ILs同时与NH3和CO2相互作用时,其吸收能力均有不同程度的下降,[HEBim][His]与[HEBim][Ala]的综合吸收效果最佳。 相似文献