共查询到20条相似文献,搜索用时 15 毫秒
1.
多羧基咪唑离子液体的酸性表征 总被引:9,自引:0,他引:9
通过电位滴定法测得多羧基咪唑离子液体的离解常数pKa值(25 ℃)在1.43~1.92范围内, 说明多羧基咪唑离子液体酸性接近乙二酸, 比丁二酸以及乙酸强. 由于多羧基咪唑离子液体结构中咪唑环具有较强的吸电子诱导效应, 使多羧基咪唑离子液体具有中等强度的酸性. 三羧基咪唑离子液体酸性比含相同阴离子的二羧基咪唑离子液体酸性强. 阳离子相同、阴离子不同的多羧基咪唑离子液体酸性强弱顺序为: HSO4- > NO3- > PF6- > H2PO4-> Cl-、Br- > CF3CO2- > BF4- > CF3SO3-. 同时, 吡啶红外光谱探针法研究表明, 多羧基咪唑离子液体具有Brønsted酸性. 相似文献
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在离子液体1-丁基-3-甲基咪唑乙酸盐([bmim]OAc)催化下,苯酚和碳酸丙烯酯一步合成了丙二醇苯醚.系统考察了反应温度、反应时间及催化剂用量对反应性能的影响,在优化的反应条件下,丙二醇苯醚的收率达79%.同时研究了不同咪唑鎓离子液体的阴阳离子的种类对催化反应的影响,发现咪唑鎓中的C2-H对反应有极大的促进作用,咪唑鎓通过提供氢键能力活化反应底物碳酸丙烯酯;同时,离子液体的阴离子也对反应有很大的影响,阴离子通过接受氢键能力活化另一反应底物苯酚.离子液体阴阳离子通过提供和接受氢键协同催化苯酚与碳酸丙烯酯的反应.离子液体循环使用5次,其活性未见明显降低. 相似文献
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FU Hai-ying ZHU Guang-lai WU Guo-zhong SHA Mao-lin DOU Qiang .Laboratory of Radiation Chemistry 《高等学校化学研究》2011,(4):688-692
The steady-state fluorescence spectra and molecular dynamics simulations were explored to investigate the temperature dependent organization in some imidazolium ionic liquids:1-butyl-3-methylimidazolium hexafluo-rophosphate([bmim][PF6]),1-ethyl-3-methylimidazolium ethylsulfate([emim][EtSO4]) and 1-butyl-3-methylimida-zolium tetrafluoroborate([bmim][BF4]).The pure room temperature ionic liquids(ILs) exhibit a large red shift at more than an excitation wavelength of around 340 nm,which demonstrates the hetero... 相似文献
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Pandurangan Ganapathi 《合成通讯》2013,43(18):2135-2141
The synthesis of substituted imidazolium-type ionic liquids via a simple method is described. Our synthesized ionic liquids are more useful in the catalytic behavior of the Mannich reaction. 相似文献
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FangShengJIANG HuaYU GeGAO RuGangXIE 《中国化学快报》2005,16(3):321-324
Benzoin condensation promoted efficiently in three imidazolium based room temperature ionic liquids [bmim]Br, [bmim]BF4 and [Bnmim]BF4 is reported for the first time. Benzoins were obtained in up to 91% yield within less than 30 min under mild conditions. 相似文献
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Ionic liquids (ILs) can be considered as environmentally friendly solvent, but they have the ability to dissolve in water and accumulate in the environment. Therefore, the toxicity of ILs should be assessed in order to prevent their harm to human and environment. This study was carried out to investigate the toxicity of ILs towards marine and freshwater fish. Three ILs have been tested, which are 1-Butyl-3-methylimidazolium hydrogen sulfate and 1-Butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide toward marine fish and 1-Hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide toward freshwater fish. Two different marine fish were employed, which are: Cephalopholis cruentata (grouper) and Lates calcarifer (barramundi). For freshwater fish, male Poecilia reticulate (guppy) was employed. The toxicity tests were conducted according to OECD (Organisation for Economic Cooperation and Development) guideline 203. For 1-Butyl-3-methylimidazolium hydrogen sulphate [BMIM][HSO4], the median lethal concentration (LC50) estimated toward Cephalopholis cruentatato be 199.98 mg.L-1. For 1-Butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide [BMIM][TFSI], LC50 estimated toward LatesCalcariferto be 374.11 mg.L-1. While, for 1-Hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, [HMIM][NTf2], LC50 estimated toward Poecilia Reticulate to be 207.49 mg.L-1. All the LC50 values obtained can be identified as practically nontoxic liquids based on Acute Toxicity Rating Scale by Fish and Wildlife Service (FWS). As to our knowledge, there is no previous reported toxicity studies of [BMIM][HSO4] and [BMIM][TFSI] on marine fish and [HMIM] [NTf2] on freshwater fish. Thus, this paper can be used as a benchmark for researchers who are dealing with these three ILs. 相似文献
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离子液体的绿色合成及环境性质 总被引:17,自引:0,他引:17
针对离子液体的绿色合成及应用过程中的环境性质,对离子液体常规合成的改进、无溶剂的微波和超声辅助合成等方面的研究进展进行了总结,对离子液体在生物体内的累积程度、离子液体的毒性和降解性等方面的研究进行了介绍。 相似文献
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作为一种新型低污染的绿色溶剂,离子液体近来受到多方关注。文章综述了离子液体合成和功能化设计方面的研究进展,微波和超声波辅助合成离子液体与常规方法相比所需反应时间短、产率高,表现出一定优势。 相似文献
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Synthesis and Characterization of Dual Acidic Ionic Liquids 总被引:1,自引:0,他引:1
Xiao Hua WANG Guo Hong TAO Zi Yan ZHANG Yuan KOU 《中国化学快报》2005,16(12):1563-1565
Novel ionic liquids with dual acidity, of which the cation contains Brφnsted acidity and anions contain Lewis acidity were synthesized. These ionic liquids obtained were identified by NMR, FF-IR, SDT and FAB-MS. Their acidities were determined by pyridine probe on IR spectrography. 相似文献
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运用密度泛函理论B3LYP方法及6-311++G(d,p)基组对11种咪唑氟硼酸离子液体进行了研究.选择相应化合物的离子体系{[XIM][BF4]n}(n-1)-(n=2,3)作为研究对象,即研究体系由一个烷基咪唑阳离子XIM+和2-3个BF4-阴离子构成,对其进行结构优化.在优化得到的最低能量构型的基础上计算了分子内阳离子与阴离子间的相互作用能,同时考虑了基组重叠误差的修正.结果表明所研究离子体系的离子间相互作用能与离子液体的实验熔点之间存在明确的线性关系,并且所得到的线性方程与氨基酸阳离子型离子液体中存在的线性关系相近.我们的工作为今后借助量子化学方法设计功能化离子液体提供了一定的理论基础. 相似文献
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介绍了离子液体作溶剂、助溶剂、催化剂和反应试剂与微波协同促进有机合成的研究进展。离子液体与微波协同促进有机合成反应,缩短了反应时间,提高了反应的选择性和产率,对环境更加友好。 相似文献
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A. Heintz J. K. Lehmann E. Schmidt A. Wandschneider 《Journal of solution chemistry》2009,38(8):1079-1083
Diffusion coefficients of the ionic liquids [C2MIM][EtSO4], [C4MIM][OcSO4], [C2MIM][NTf2] and [C4MIM][NTf2] in water at high dilution have been measured using the Taylor dispersion technique. Data on the diffusion coefficients have
been obtained for each solute at six temperatures between 288 and 313 K. The data have been fitted by the Arrhenius equation
and activation energies of diffusion have been determined. Effective radii of the ionic liquid molecules have also been obtained
using the Stokes–Einstein relationship. 相似文献
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Ling HE Guo Hong TAO Wei Shan LIU Wei XIONG Tao WANG Yuan KOU 《中国化学快报》2006,17(3):321-324
Lewis acidic ionic liquids have been receiving extensive interest as green substitute for H2SO4, HF and AlCl3 catalysts in chemical processes1. In view of the principles of green chemistry2, ionic liquids themselves are highly expected to be obtained via … 相似文献
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ZhangGaoLE ZhenChuCHEN YiHU QinGuoZHENG 《中国化学快报》2005,16(2):155-158
1-(α-Alkoxyalkyl)benzotriazoles are readily synthesized from three-component condensation of benzotriazole with aldehyde and alcohol in ionic liquid [Bmim]PF6. 相似文献
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QingHaiCAI YongKuiSHAN LiYiDAI BiXiaSU MingYuanHe 《中国化学快报》2003,14(5):523-524
A new type of ionic liquids containing cation of diacetone acrylamide [or N-(1,1-bismethyl-3-oxo-butyl)acrylamide]and anions such as CH3COO^-(Ac),CF3COO^-(TF),BF4^-(BF),PF6^-(PF),HSO4^-(SO) and Cl^-(Cl) were prepared by normal neutralization.The obtained ionic liquids were identified by FT-IR and ^1H NMR spectroscopy.However,their properties such as meliting point,conductivity,viscosity etc,were determined. 相似文献