共查询到18条相似文献,搜索用时 46 毫秒
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超临界流体的共溶剂效应和混合流体研究进展 总被引:2,自引:0,他引:2
共溶剂的出现极大地拓展了超临界流体的应用范围,推动了超临界流体科学与技术的发展。本文从相行为和分子间相互作用热力学的角度,对相行为测定、量热技术、光谱技术和分子模拟等在超临界流体中共溶剂效应的研究作了综述,主要介绍超临界流体中共溶剂的作用机理和混合流体在临界点附近热力学性质研究,并对其未来发展方向进行了展望。 相似文献
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超临界CO2/离子液体体系 总被引:2,自引:0,他引:2
超临界CO2和离子液体是两种具有优异性能的绿色化学试剂,本文介绍了将两者结合反应,分离体系的物化性质和多种绿色化学过程。利用超临界CO2可以广泛地萃取离子液体中的不挥发性化合物而不导致离子液体及其中催化剂的流失,在加氢、醛化、甲酰化等反应,分离过程中的应用表明,过程具有很好的反应分离特性和环境友好性,应用前景广阔。 相似文献
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超临界流体萃取分离离子液体与有机物及其相平衡的研究 总被引:6,自引:0,他引:6
离子液体具有一些优良的物理和化学性质,非常有希望成为传统有机溶剂的替代溶剂.但是如何从过程物流中分离和回收离子液体将是其工业化应用的一个很大挑战.蒸馏、液液萃取和超临界萃取是目前已知的三个可行的方法.其中超临界萃取可应用于离子液体与挥发的或相对不挥发的有机物的分离,而且不存在相间交叉污染.本文从二元体系相平衡、三元体系相平衡、模型化研究和萃取实验结果方面介绍了超临界萃取方法的最新研究进展,在此基础上提出了用超临界丙烷替代超临界二氧化碳作为萃取溶剂的新思路,并探讨了该领域今后的研究方向和工业化前景. 相似文献
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超临界流体技术应用进展 总被引:12,自引:0,他引:12
超临界流体技术具有许多传统技术所没有的快速、高效、低能耗、污染少等优点。本文综述了其在分离、分析、材料制备和作为反应介质等方面的应用现状。 相似文献
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考察了填充柱超临界流体色谱法(SFC)中的样品溶剂及连续进样等因素对化合物保留行为变化的影响规律。以超临界CO2或含低体积分数甲醇的CO2为流动相时,氨基柱组分的保留时间随着样品溶剂的极性增大而增大,而溶剂对C18柱上组分的保留时间影响不大;在C18柱上,溶剂对连续进样的后继效应不强;而在氨基柱上,甲醇溶液的后续效应比丙酮、氯仿溶液的后续效应强。当甲醇的体积分数大于1.0%时,溶液的效应明显减弱。 相似文献
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Joanna Shaofen Wang Dr. Chrystal N. Sheaff Dr. Byunghoon Yoon Dr. R. Shane Addleman Dr. Chien M. Wai Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(17):4458-4463
Super powers! Uranium(VI) ions can be extracted from aqueous solutions into supercritical CO2 (sc‐CO2) via an ionic liquid phase that contained tri‐n‐butyl phosphate (TBP) as a complexing agent (see figure). This process has potential applications in the nuclear industry for removing actinides from nuclear waste.
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Adsorption isotherms for supercritical fluids are calculated using lattice theory. Results are compared with experimental data for methane on graphon and for carbon dioxide on coal. It is shown that the model reflects the peculiar features in adsorption isotherms of supercritical fluids (in particular, a maximum in the adsorption with increasing pressure). The analysis shows that there is two layer adsorption over a wide range of densities. 相似文献
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Andrea Amadei Andrea Ciccioli Antonello Filippi Caterina Fraschetti Massimiliano Aschi 《Molecules (Basel, Switzerland)》2022,27(22)
A theoretical-computational procedure based on the quasi-Gaussian entropy (QGE) theory and molecular dynamics (MD) simulations is proposed for the calculation of thermodynamic properties for molecular and supra-molecular species in the gas phase. The peculiarity of the methodology reported in this study is its ability to construct an analytical model of all the most relevant thermodynamic properties, even within a wide temperature range, based on a practically automatic sampling of the entire conformational repertoire of highly flexible systems, thereby bypassing the need for an explicit search for all possible conformers/rotamers deemed relevant. In this respect, the reliability of the presented method mainly depends on the quality of the force field used in the MD simulations and on the ability to discriminate in a physically coherent way between semi-classical and quantum degrees of freedom. The method was tested on six model systems (n-butane, n-butane, n-octanol, octadecane, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic pairs), which, being experimentally characterized and already addressed by other theoretical-computational methods, were considered as particularly suitable to allow us to evaluate the method’s accuracy and efficiency, bringing out advantages and possible drawbacks. The results demonstrate that such a physically coherent yet relatively simple method can represent a further valid computational tool that is alternative and complementary to other extremely efficient computational methods, as it is particularly suited for addressing the thermodynamics of gaseous systems with a high conformational complexity over a large range of temperature. 相似文献
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物理化学尤其是化学热力学公式多、易混淆,学生记忆负担较重。介绍了巧记物理化学中热力学函数关系式和简要分析二元系统固液平衡相图的方法,并以熵变计算为例介绍了物理化学的解题技巧。 相似文献
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Supercriticalfluids(SCFs)havemanyfeatures.Forexample,density,dielectricconstantandsolubilityparametercanbealteredbetweengas-likeandliquid-likethroughmodestmanipulationsofpressureand/ortemperature.Inrecentyears,differenttechniqueshavebeenusedtostudythemolecularinteractionsinSCFs,suchasUV',FTIR',fluorencence',andpartialmolarvolumemeasurement4.Itisknownthatsolvent(SCF)-soluteclustersexistinSCFmixturesinhighcompressibleregion#.Molecularsimulationssshowedthatself-associationofthemoleculesex… 相似文献