Fe-Al-Mg-MMH/钠质蒙脱土分散体系触变性研究

研究了Fe-Al-Mg型混合金属氢氧化物(简称MMH)/钠质蒙脱土(简称MT)分散体系的触变性,发现在不同MMH/MT质量比(R)条件下,分散体系可分别呈现正触变性和负触变性.在所研究的R范围(0～0.091)内,随R增大,体系的触变性发生正触变性-复合触变性-负触变性的转化.考察了高速剪切分散后,测定粘度变化前的静置时间(ts)和测定粘度时的剪切速率(DL)对触变性的影响.探讨了各种触变性产生的原因,提出了“分散粒子-空间连续网络结构-密实聚集体”和“分散粒子-密实聚集体-密实聚集体簇”机理,较合理地解释了观察到的复合触变现象.     

l—对甲苯磺酰乳酸乙酯合成中产率分析方法的研究

报道了实验室可行、工业生产实用的l－对甲苯磺酸乳酸乙酯产率的分析方法,采用K2CrO4-K2Cr2O7混合指示剂,其最佳配比为K2CrO4:K2Cr2O7=6:1（质量比）,体系的最佳pH为5．8,测得l-乳酸乙酯与对甲苯碘酰氯反应制备和的l-对甲苯磺酰乳酸乙酯的产率为94．0％。     

正、负离子表面活性剂混合体系溶致液晶生成的相行为

研究了烷基(C8,C12,C14)三甲基溴化铵、烷基(C12,C14)溴化吡啶与烷基(C8,C12)硫酸钠混合体系溶致液晶形成的条件与结构的变化.在高浓度的水溶液中,随着正、负离子表面活性剂摩尔比接近于1,液晶结构由六角相过渡为层状相.表面活性剂非极性链长改变,对相行为影响显著,短碳链的正、负离子表面活性剂混合体系,在等摩尔比时,体系为层状液晶或立方液晶为主,夹杂少许沉淀.随碳链增长,两类表面活性剂间的静电吸引效果表现为生成沉淀的摩尔比例范围变宽,沉淀量增多,共存的液晶相减少,甚至消失.若只改变正离子的极性头基,季胺盐比吡啶盐与烷基硫酸盐的作用要强,形成不溶物的混合摩尔比例范围更宽.     

用于CO2分离的混合基质膜中填充剂的研究进展

高效、绿色和低能耗的CO_2捕集技术是解决能源气体净化和温室气体减排问题的关键。膜分离技术以其高效、节能、低碳等特点在CO_2捕集领域具有潜在的发展前景。目前,CO_2分离膜的研究主要集中在混合基质膜内的填充剂,通过调控填充剂解决膜内渗透性和选择性间的"博弈"效应。近年来,研究者们发现填充剂通常是影响混合基质膜分离性能的关键因素,采用不同的填充剂可改善混合基质膜的气体分离性能。基于此,本文对目前已经开发出的填充剂进行了归纳总结,以便为设计开发新型混合基质膜用于CO_2分离提供参考。     

Application of a chemical equilibrium model to thermodynamic functions of transfer of alcohols from water to aqueous surfactants

In ternary aqueous solutions, hydrophobic solutes such as alcohols tend to aggregate with surfactants to form mixed micelles. These systems can be studied by meas of the functions of transfer of hydrophobic solutes from water to aqueous solutions of surfactant. These thermodynamic functions often go through extrema in the critical micellar concentration (CMC) region of the surfactant. A simple model based on interactions between surfactant and hydrophobic solute monomers, on the distribution of the hydrophobic solute between water and the micelles and on the shift in the CMC induced by the hydrophobic solute, can simulate the magnitude and trends of the transfer functions using parameters which are mostly derived from the binary systems. In order to check the model more quantitatively, volumes and heat capacities of transfer of alcohols from water to aqueous solutions of a nonionic surfactant, octyldimethylamine oxide, were measured. A quantitative agreement was achieved with three adjustable parameters. Good fits are also obtained for the transfers to the ionic surfactants, octylamine hydrobromide and sodium dodecylsulfate. When the equilibrium displacement contribution is small, the distribution constants and the partial molar properties of the alcohols in the micellar phase agree well with the parameters obtained with similar models.     

Use of Different Salt Solutions in Salting-Out TLC of Co(III) Complexes on Silica Gel

Saturated aqueous solutions of 28 different salts have been studied as a potential mobile phases for salting-out thin-layer chromatography, on silica gel, of a series of four mixed bis-aminocarboxylato cobalt(III) complexes. In addition, by linear regression analysis of chromatographic data obtained for fifteen mixed aminocarboxylato Co(III) complexes (four series) with solutions of ammonium chloride, three alkali metal chlorides, and four alkaline earth metal chlorides, four linear dependences previously established on different adsorbents with (NH₄)₂SO₄ solutions were confirmed. The qualities of the separations achieved with the salts were compared and Li⁺, Mg²⁺, and Ca²⁺ chlorides are proposed as the most suitable.     

Simultaneous separation and analysis of water- and fat-soluble vitamins on multi-modal reversed-phase weak anion exchange material by HPLC-UV

Several methods for the separation of vitamins on HPLC columns were already validated in the last 20 years. However, most of the techniques focus on separating either fat- or water-soluble vitamins and only few methods are intended to separate lipophilic and hydrophilic vitamins simultaneously. A mixed-mode reversed-phase weak anion exchange (RP-WAX) stationary phase was developed in our laboratory in order to address such mixture of analytes with different chemical characteristics, which are difficult to separate on standard columns. The high versatility in usage of the RP-WAX chromatographic material allowed a baseline separation of ten vitamins within a single run, seven water-soluble and three fat-soluble, using three different chromatographic modes: some positively charged vitamins are eluted in ion exclusion and ion repulsion modes whereas the negatively charged molecules are eluted in the ion exchange mechanism. The non-charged molecules are eluted in a classical reversed-phase mode, regarding their polarities. The method was validated for the vitamin analysis in tablets, evaluating selectivity, robustness, linearity, accuracy, and precision. The validated method was finally employed for the analysis of the vitamin content of some commercially available supplement tablets.     

Mixed‐mode chromatography integrated with high‐performance liquid chromatography for protein analysis and separation: Using bovine serum albumin and lysozyme as the model target

A type of mixed‐mode chromatography was integrated with high‐performance liquid chromatography for protein analysis and separation. The chromatographic behavior was tested using bovine serum albumin and lysozyme as model proteins. For the mixed‐mode column, the silica beads were activated with γ‐(2,3‐epoxypropoxy)‐propytrimethoxysilane and coupled with 4‐mercaptopyridine as the functional ligand. The effects of pH, salt, and the organic solvent conditions of the mobile phase on the retention behavior were studied, which provided valuable clues for separation strategy. When eluted with a suitable pH gradient, salt concentration gradient, and acetonitrile content gradient, the separation behavior of bovine serum albumin and lysozyme could be controlled by altering the conditions of the mobile phase. The results indicated this type of chromatography might be a useful method for protein analysis and separation.     

利用光纤法布里-珀罗谐振器干涉透射波长同时测量混合溶液中多溶质浓度

为了同时探测混合溶液中多种溶质的浓度,提出一种用光纤法布里-珀罗谐振器作为传感器测量混合溶液中多溶质浓度的测量系统.从理论上分析了光纤法布里-珀罗谐振器干涉透射波长与混合溶液浓度之间的关系,采用光纤法布里-珀罗谐振器干涉透射波长实现了高准确度同时测量混合溶液中多溶质浓度的原理和可行性.构建了由InGaAs发光二极管光源、光纤耦合器、FFPR传感器、光电信号转换和放大器、光谱分析仪等组成的测量系统.对乙醇和甘油的9组标准混合溶液进行测量实验,并用测量结果标定了混合溶液中各溶质浓度与光纤法布里-珀罗谐振器传感器干涉透射波长之间的数学解析关系式.根据数学关系式用Action Script 2.0脚本语言编写程序,计算机实时监控了混合溶液中各溶质浓度的变化过程.     

Fabrication and electrochemistry study of multi-thiol coronary molecule monolayers

Single-component monolayer of novel multi-thiol coronary molecule and two-component mixed monolayer composed of coronary molecule and n-alkanethiol on gold substrates are described. The assembly of monolayers is characterized by ellipsometry, infrared spectroscopy and X-ray photoelectron spectroscope. The electrochemical properties of the single- and two-component monolayers are evaluated by cyclic voltammetry and electrochemical impedance spectroscopy experiments. Coronary molecule with multi-thiol groups has the ability to form stable monolayer via the interaction of mercapto groups and Au surface. Electrochemical impedance measurements indicate that 89.9% of the gold surface is blocked by the coronary molecule, which is attributed to the special spatial structure of the coronary molecule. The uncovered site on gold surface in coronary molecule monolayer could be occupied by the second suitable molecule. The mixed monolayer prepared by stepwise assembly of coronary molecule and n-alkanethiol has complete compact packing and few defects.