醌类化合物的超临界流体萃取研究进展

综述了国内近20年来超临界流体萃取技术应用于醌类化合物分离的研究进展,重点介绍了超临界流体萃取技术在中草药中醌类化合物的分析测定方面的应用,分析了影响醌类成分提取效果的主要因素,优化萃取温度和萃取压力能够改善琨类化合物的分离效果,夹带剂的使用则有效地提高了超临界流体的萃取能力。     

超临界流体技术研究进展

本文综述了超临界流体技术在萃取、材料制备、化学反应及相转移催化等方面的应用, 介绍了有代表性的超临界萃取和反应装置。对今后工作提出了一些建议。     

金属离子的超临界流体萃取技术的进展

超临界流体萃取技术在分离方面发展迅速,应用前景十分广泛。文中综述了超临界流体技术的萃取机理及对金属离子萃取的研究。     

超临界流体萃取技术在乏燃料后处理中的应用

未来的动力堆乏燃料具有高燃耗、高钚含量和燃料类型多样等特点,采用传统的溶剂萃取法流程处理将面临很大挑战,而干法后处理技术虽经多年研究,仍有许多问题有待解决,因此有必要探索新的非水法后处理技术。将超临界流体萃取应用于乏燃料后处理可以简化后处理流程,大量减少二次废液的产生,具有很好的发展前景。本文综述了超临界流体萃取技术在乏燃料后处理中的应用研究,对基于超临界萃取技术的乏燃料后处理概念流程进行了评述。对将电化学插层法与超临界流体萃取技术结合,用于处理高温气冷堆乏燃料的可行性进行了讨论。     

超临界流体萃取技术在中草药有效成份提取中的应用

本文介绍了超临界流体萃取技术的基本原理、优越性以及中草药有效成分提取中的应用。     

衍生-超临界流体萃取金属离子的技术与进展

综述了近年来衍生-超临界流体萃取环境样品和环境模拟样品中金属离子的研究报道,结合作者的研究工作,着重评述了超临界流体萃取不同环境样品、环境模拟样品中金属离子的原理、萃取过程的动力学模型、衍生剂的选择原则、金属螫合物在超临界流体中的溶解度理论、影响萃取效率的因素、金属离子超临界流体萃取应用研究现状与进展等。利用流体与基体改性技术实现了金属离子和金属螯合物的超临界流体萃取,且在萃取体系中加入适量的表面活性剂能显著提高萃取效率。     

超临界萃取装置的研制及其应用

超临界流体萃取是近的上来兴起的一种新的分离技术，报道了将超临界萃取原理与回流技术相结合研制的二氧化碳回流中低压超临界流体萃取设备，解决了关键实验手段，通过应用证明设备可靠，费用低廉，有实用价值。     

超临界流体萃取技术在核废料处理方面的应用

超临界流体;二氧化碳;综述;超临界流体萃取技术在核废料处理方面的应用     

超临界氮气对聚苯乙烯微观形态的影响——喷泉效应与层状结构的形成

当流体的温度和压力处于它的临界温度和临界压力以上时,称该流体处于超临界状态,为超临界流体.超临界流体表现出许多不同于一般气体和液体的特性,如溶质在超临界流体中的溶解度可较同温常压下溶质在同种气体中的溶解度大很多,超临界流体密度与液体的密度相近,其粘度却比液体小近百倍,导热系数比常压气体大得多等.由于超临界流体具有这些不同寻常的特性,因而以超临界萃取为代表的超临界流体已有广泛的工业应用.近年来超临界流体在聚合物加工中的应用逐渐受到重视,如超临界分级、造粒、气体辅助注塑成型、发泡成型等[1～3].     

超临界CO_2萃取中草药活性成分溶剂特性研究

针对超临界二氧化碳流体的局限性和中草药中活性成分的特殊性,研究了超临界二氧二化碳流体、改性剂和混合溶液的溶解度参数,提出了改性剂的选择原则。结果表明:萃取温度和压力是影响超临界二氧化碳流体和混合溶剂溶解度参数的主要因素,改性剂的种类和浓度影响萃取体系的溶解特性。     

超临界流体中的催化反应

介绍了近年超临界流体在催化反应中的理论研究和应用,阐述了超临界流体用于催化反应的优越性。     

Supercritical fluid chromatography (SFC) of linear and cyclic components in technical silicone oils

Since technical silicone oils are widely used, high performance analysis and exact quality control are necessary. The quantity of low molecular cyclic components is of special importance for the properties of the oils. Supercritical Fluid Chromatography (SFC) provides a facility for determining such cyclic components. Accurate assignment of linear and cyclic polydimethylsiloxanes is possible by coupling SFC with mass spectrometry (MS) or by using standard materials.     

Gradient separation of pharmaceuticals employing supercritical CO2 and modifiers

Sub- and Supercritical Fluid Chromatography (SFC) were used to separate seven purine and pyrimidine-based drugs. A two-pump system was used, where one pump delivered the carbon dioxide, and the other pump delivered modifier. The modifiers used in this work were methanol, and methanol containing 0.001 M tetrabutylammonium hydroxide. Two of the compounds studied were hydrochloride salts. These compounds were analyzed by a Supercritical Fluid Extraction (SFE)/SFC method.     

Identification and Isotopic Analysis of Safranal from Supercritical Fluid Extraction and Alcoholic Extracts of Saffron

Abstract

Saffron is one of the most expensive spices. Consequently, it is not so difficult to understand that fraudulent saffron exists. Thus, it was interesting to study the most important flavouring component, in terms of aroma, volatile compound of saffron - safranal - by ¹³C isotopic analysis. Five saffron samples from different countries have been analysed. Safranal has been extracted by methanol or by Supercritical Fluid Extraction (SFE). The results indicate that there is a significant difference between the synthetic safranal and the natural one. On the contrary, it is difficult to conclude on the difference between the various geographical origins, as the isotopic variations are small. Moreover, it has been found that Supercritical Fluid Extraction allowed the selective extraction of volatile compounds from saffron under optimised conditions. It is a cleaner and faster method of extraction compared to the extraction using organic solvent. Nevertheless, an isotopic fractionation occurs in relation to the extraction yield of safranal.     

Book Reviews

Ultraviolet Spectroscopy and UV Lasers, Edited by P. Misra and M. A. Dubinskii Supercritical Fluid Technology in materials Science and Engineering (Syntheses, Properties and Applications), Edited by Ya-Ping Sun This revised version was published online in August 2006 with corrections to the Cover Date.     

渣油加氢转化催化剂初期结焦规律的研究

以孤岛减压渣油及其超临界流体萃取分馏所得的窄馏分为原料,采用齐鲁石化公司胜利炼油厂VRDS装置的主催化剂,在高压釜反应器内考察了渣油加氢转化催化剂的初期结焦规律。结果表明,焦炭的生成是一个动态过程,其产率和性质与反应体系的温度、时间、氢气初始压力及原料的性质密切相关;结焦催化剂的孔壁焦炭沉积和堵孔现象严重,导致其比表面积大大减小,孔分布向小孔范围迁移。     

Separation of T-MAZ ethoxylated sorbitan fatty acid esters by reverse phase chromatography

Summary The method for determination of T-MAZ ethoxylated sorbitan fatty acid esters is described. This work demonstrates that with a less retentive C₈ alkyl bonded phase packing, reverse phase chromatography can be used to analyze nonionic polymer mixtures with a molecular weight range of 900 to 1500. Using a gradient elution, a complete separation of T-MAZ oligomers was achieved, comparable to that obtained by Supercritical Fluid Chromatography (SFC). Isocratic elution is used to quantify T-MAZ and the detection limit is 321 ppm, which is acceptable for polymers with high molecular weights and no UV-absorbing chromophores. This work also shows the comparison of the separations of T-MAZ using gel permeation chromatography and reverse phase chromatography.     

Application of direct on-line coupling of HPLC and SFC with 1HNMR spectroscopy for the investigation of monomeric acrylates

The separation of monomeric acrylates was performed with High Performance Liquid Chromatography (HPLC) and Supercritical Fluid Chromatography (SFC). A direct on-line structural assignment of all compounds by continuous-flow ¹HNMR spectroscopy is possible with both separation techniques. The direct SFC-NMR coupling offers the advantage that the recorded continuous-flow ¹HNMR spectrum is not obscured by solvent signals.     

Control of flow rate in supercritical fluid chromatography

Summary Supercritical Fluid Chromatograph was constructed using two pumps and two restrictors. With this system in conjunction with the fused silica column packed with relatively large particles (40 μm), the flow rate was controlled both for isobaric and pressure programmed operations. Application of this system to the determination of molecular weight distribution of polystyrene oligomers was presented.     

太湖水体中有机污染物的分析

利用超临界流体萃取与热脱附两种样品预自理方法的优势互补,与气相色谱分析相结合对太湖水体中不同沸点有机污染物进行了分析,发现太湖水中除了烃类污染物外还存在大量含氮有机污染物。其分布表明入湖河道中排放的工业污染物的流入是导致太湖水富营养化的一个重要因素。