水热驱动的Claisen重排-亲核加成串联反应法合成3-甲基-5-羟基-7-羧基异色满-1-酮

研究了基于水热驱动的5-烯丙氧基间苯二甲酸二甲酯的Claisen重排-亲核加成的串联反应,合成了3-甲基-5-羟基-7-羧基异色满-1-酮（K1）,其结构经¹H NMR, FT-IR和元素分析确证,单晶衍射表征了其晶体结构。通过改变实验条件,获得了原料能够完全转化的临界温度和浓度,分别为120 ℃和0.02 g/mL。     

固相膜萃取-超声解吸-气相色谱-质谱法分析水中酞酸酯类化合物

酞酸酯(PAEs)是一种常用的增塑剂,由于其广泛应用已经对环境造成了污染.本研究建立了固相膜萃取-超声解吸-气相色谱-质谱分析水中酞酸酯类化合物的方法.对萃取条件、解吸条件进行了优化,确定了最佳的实验条件.在水浴温度40℃,超声功率50%的条件下超声7 min,测定水中PAEs的检出限(S/N>3)在0.05 ~0.26 μg/L之间;对不同基质空白样品进行加标回收实验,回收率在76.2%~112.3%之间,相对标准偏差小于10%.     

气相色谱-质谱联用分析2-氯-5-三氯甲基吡啶

2-氯-5-三氯甲基吡啶是重要的农药中间体.采用气相色谱-质谱联用法,对高效除草剂盖草能的中间体2-氯-5-三氯甲基吡啶的分析条件进行了探讨和优化.使用Rts-5MS毛细管柱,EI电离源,实验结果的线性关系良好,相关系数r=0.9921,回收率为99.05%,相对标准偏差为0.78%.     

固定化β-葡萄糖醛酸酶反应器的制备及其在4-甲基亚硝胺基-1-(3-吡啶)-1-丁醇的O-糖苷化合物分析中的应用

采用溶胶-凝胶法,以丙烯酰胺作为单体,制备了基于有机-硅胶杂化整体柱的β-葡萄糖醛酸酶反应器。优化了硅酸甲酯和γ-(甲基丙烯酰氧)丙基三甲氧基硅的物质的量的比、丙烯酰胺和聚乙二醇的用量,以及水浴温度等制备条件,获得了孔隙均匀、通透性良好、机械强度高的有机-硅胶杂化整体柱。采用光学显微镜和扫描电镜表征杂化整体柱。进一步将β-葡萄糖醛酸酶共价键合在整体柱上,以4-甲基亚硝胺基-1-(3-吡啶)-1-丁醇(NNAL)的O-糖苷化合物(NNAL-O-Gluc)为底物研究酶反应器的水解效果,实验结果证明酶反应器在室温条件下的水解效率大大提高,实现了NNAL-O-Gluc高效水解与分析,解决了目前NNAL-O-Gluc分析中前处理水解效率低的问题。     

闪蒸-毛细管气相色谱-质谱法分析中草药的挥发性成分

本文采用闪蒸-毛细管气相色谱-质谱法对姜黄、茅苍术、小茴香、肉桂的主要挥发性组分进行了分析,其结果与常规分析相符,对中草药闪蒸分析的条件进行了探讨,实验结果证明,闪蒸分析法是研究中草药挥发性成分的一种简便、快速、有效的微量分析方法。     

1,1,1-三氟-2-甲基-2-丙醇合成工艺研究

以氯甲烷(2)为原料制备甲基氯化镁格氏试剂;以三氯化镓为催化剂,甲基氯化镁与1,1,1-三氟丙酮(3)反应,经水解制得1,1,1-三氟-2-甲基-2-丙醇(1).产物结构经1 H-NMR、13 C-NMR、19 F-NMR及MS表征;通过单因素、正交实验和放大重复性实验确定了最佳反应条件:溶剂为正丁醚、格氏试剂浓度3 ...     

微囊藻毒素的2-甲基-3-甲氧基-4-苯基丁酸检测方法的研究

2甲-基-3-甲氧基-4-苯基丁酸(MMPB)法是检测微囊藻毒素(Microcystins,MC)的重要方法之一。本文研究了温度、pH值、反应时间和氧化剂浓度等实验参数的影响,并在优化条件下采用气相色谱法对水中的微囊藻毒素进行检测。实验得到的最佳反应条件为:pH=9,初始反应温度2℃反应1 h,再升温至25℃反应2 h;KMnO4的初始浓度为0.0156 mol/L。本法对水溶液中的微囊藻的检出限为0.0225μg,回收率为93.5%。     

β-环糊精交联聚合物包结α-吡啶偶氮-β-萘酚络合物树脂吸附富集痕量金属的研究

以环氧氯丙烷为交联剂合成的β-环糊精聚合物树脂与1-(2-吡啶偶氮-2-萘酚形成的包结络合物能与多种金属离子形成稳定的吸附络合物.本文报道了以这种包结络合物吸附富集铜、镉、镍与锰的实验条件以及用原子吸收分光光度法测定痕量铜、镉、镍与锰的研究.实验中详细地研究了有关的吸附条件及富集倍数,提出了一种富集与测定痕量金属的新方法.     

高效液相色谱-氢化物发生-原子荧光光谱在线联用系统分析中成药中砷化合物形态

建立了高效液相色谱-氢化物发生-原子荧光光谱砷形态分析在线联用系统,考察了不同实验条件对4种砷形态化合物（As^Ⅲ,DMA^Ⅴ,MMA^Ⅴ和As^Ⅴ）分离分析的影响,优化了实验条件.在优化的实验条件下,采用pH 5.8的磷酸盐缓冲溶液为流动相,梯度洗脱,10 min之内4种砷形态达到基线分离.进样20μL,测定4种形态的检出限分别为：As^Ⅲ2.76 ng/mL,DMA^Ⅴ7.37 ng/mL,MMA^Ⅴ2.86 ng/mL和As^Ⅴ5.22 ng/mL,相对标准偏差RSD在2.9%～4.2%之间.该联用系统灵敏度高,准确性好,分离分析了部分市售中成药中的不同砷形态化合物.     

2-异丙基-4-甲基-6-羟基嘧啶的溴量法测定

2-异丙基-4-甲基-6-羟基嘧啶(以下简称羟基嘧啶),系有机磷杀虫剂地亚农的主要中间体。该化合物的常规化学分析方法,未见报导。作者经实验证明,该化合物中嘧啶环上的氢在给定的条件下,可被溴定量取代,以此可推算其羟基嘧啶的含量。实践证明,方法具有操作简便、快速、准确等优点,适用于工业生产常规分析。本方法曾用紫外分光光度法作了验证测试,得到了平行的结果。 2-异丙基-4-甲基-6-羟基嘧啶的结构式:     

小环化合物中饱和碳质子化学位移的计算

小环化合物由于其张力、构型、构象和各向异性效应等原因,环碳上质子化学位移缺乏规律性,难以预测,对此作者曾提出一种近似算法。本文根据303种小环化合物中饱和碳质子的化学位移实验数据,将适于计算这类质子化学位移的公式表述为:     

The evaluation and use of properties of individual ions in slution

A critical examination is given of extra-thermodynamic methods for evaluation of properties of individual ions in solution. The ways in which such data may be applied, or are required in various problems concerning specific properties of electrolyte solutions and in the fields of kinetics, electrochemistry, colloid and interfacial chemistry, are outlined. Special attention is given to the problem of evaluation of individual ionic thermodynamic functions for the hydration of ions but, in some cases, corresponding data for nonaqueous solutions are available for discussion and are of interest in a comparative way. The reliability of the various methods is assessed and estimates of numerical values for various individual ionic functions are tabulated. The question of scales of individual ionic radii, on which some of the derived data depend, is also examined. The dependence of various properties for anions and for cations on ionic radius is discussed and data are plotted comparatively. It is shown that for most, but not all, properties, the values for anions are more sensitive to increasing ionic radius than are the values for cations. This behavior, as well as the exceptions, is of theoretical interest. The significance of ion-specific behavior at interfaces is considered and the importance of interactions between ions of like sign of charge is indicated.Presented at the Symposium on Electrolytes, University of Reading, September 13, 1977.     

多肽酰肼连接法合成C端香豆素修饰的泛素

C端用香豆素修饰的泛素分子（Ub-AMC）是研究蛋白质泛素化过程的重要探针.该探针分子的制备目前主要依靠生物表达结合化学修饰的方法,合成效率较低.本文使用多肽酰肼连接反应,发展出化学全合成Ub-AMC分子的新路线.该方法通过N到C顺序两次连接实现了目标分子的组装,再通过自由基脱硫反应得到天然结构的Ub-AMC分子,有望实现较大量的合成.通过酶学活性实验,证实了通过新方法合成的Ub-AMC具有预期的生物活性.     

苯酚抑制条件下亚硫酸盐氧化的本征反应动力学

亚硫酸盐的氧化是湿法烟气脱硫工艺中的重要过程. 利用间歇式反应装置, 研究了苯酚抑制条件下亚硫酸盐氧化的本征反应动力学. 结果表明, 该复杂的反应过程分两个阶段进行, 即富氧区的快速反应和贫氧区的慢速反应. 在富氧区, 苯酚、亚硫酸盐和溶解氧的分级数分别为－0.5, 1.0和2.0, 反应的表观活化能为99.2 kJ•mol－1; 在贫氧区, 苯酚、亚硫酸盐和溶解氧的分级数分别为－0.5, 1.5和0, 反应的表观活化能为 129.7 kJ•mol－1. 结合实验结果, 对苯酚抑制条件下亚硫酸盐氧化的宏观反应动力学过程进行了推断.     

Start‐up of electrophoresis of an arbitrarily oriented dielectric cylinder

An analytical study is presented for the transient electrophoretic response of a circular cylindrical particle to the step application of an electric field. The electric double layer adjacent to the particle surface is thin but finite compared with the radius of the particle. The time‐evolving electroosmotic velocity at the outer boundary of the double layer is utilized as a slip condition so that the transient momentum conservation equation for the bulk fluid flow is solved. Explicit formulas for the unsteady electrophoretic velocity of the particle are obtained for both axially and transversely applied electric fields, and can be linearly superimposed for an arbitrarily‐oriented applied field. If the cylindrical particle is neutrally buoyant in the suspending fluid, the transient electrophoretic velocity is independent of the orientation of the particle relative to the applied electric field and will be in the direction of the applied field. If the particle is different in density from the fluid, then the direction of electrophoresis will not coincide with that of the applied field until the steady state is attained. The growth of the electrophoretic mobility with the elapsed time for a cylindrical particle is substantially slower than for a spherical particle.     

计算机辅助柱色谱最优化分离氨基酸

计算机辅助柱色谱最优化分离氨基酸王琴孙，颜炳文，王寿亭，陶雪（南开大学元素有机化学研究所，天津，３０００７１）（南开大学高分子化学研究所）关键词计算机，色谱最优化，柱色谱微型计算机的发展推动了整个色谱优化领域的发展，也陆续出现了一些优化分离方法［１～...     

Luminescence spectroscopy as a tool for testing of cure kinetics of epoxy resins

In this paper, steady-state luminescence spectroscopy is used for the analysis of curing of epoxy resin. The advantage of this method is its rapidity, simplicity and sensitivity. Moreover, this method is contactless, and thus non-invasive. The aim is to analyze epoxy resin, mathematically describe its curing kinetics and determine its storage temperature. Using the photoluminescence method, a rapid procedure for obtaining the necessary technological data is achieved. This method is suitable for continuous measurement in production because there is no contact with the material, and the measurement itself can be performed very quickly. The elaborated mathematical model can serve as a basis for creating algorithms for automated data processing in case of fully robotic workplaces.     

Electrochemical behavior of electrodes containing nanostructured carbon of various morphology in the cathodic region of potentials

Voltammograms for electrodes containing nanostructured carbon of various morphology (single-walled carbon nanotubes, filament, columnar structures) are obtained in neutral aqueous electrolytic solutions. Experimental proofs for the existence of injection of solvated electrons into electrolytic solutions at moderate cathodic potentials are presented for all the electrodes. It is established that this effect is connected with the presence of atomically sharp areas on the electrode surfaces. It is assumed that the reason for the appearance of solvated electrons is the autoelectron emission at the interface between the conducting surface of the carbon material and the electrolytic solution. By studying the nitrate anion reduction it is shown that the reduction over-voltage of stable compounds may be lowered by substituting a fast homogeneous reaction of solvated electrons with the initial substance for the hindered heterogeneous stage of the first electron transfer.     

Calculation of the Liquid and Gas Permeability of Hydrophobic Low-Porosity Membranes of an Arbitrary Thickness

A method for calculating the liquid and gas permeability of hydrophobic low-porosity membranes of an arbitrary thickness is described. The calculation is based on the solution of a problem on percolation—the procedure of finding the distribution of liquid and gas over the membrane thickness. The dependence of the permeability for liquid on the share of pores that are potentially accessible to being filled with liquid is obtained for both thin and thick membranes. This dependence is of a universal nature and can easily be recalculated into a dependence of permeability on the pressure drop for membranes with any distribution of pores by size. Numerical estimates of principal characteristics for a membrane that possesses pores of three types are performed. The characteristics in question include permeabilities for liquid and gas; fluxes of the liquid; critical pressures, at which the permeability for liquid turns other than zero; and the working range of pressures, in which the membrane is capable of working normally. All these data permit the optimization of the operation of similar membranes, in particular, gas-delivering membranes that are used in hydrogen–oxygen fuel cells with a solid polymer electrolyte.     

The effect of the order of the autocatalysis on the transverse stability of reaction fronts

A linear stability analysis of planar reaction fronts to transverse perturbations is considered for a system based on an autocatalytic reaction of general order p. Dispersion curves, plots of the growth rate sigma against a transverse wavenumber k, are obtained for a range of values of p and D, where D is the ratio of the diffusion coefficients of autocatalyst and substrate. A value D(0) of D, dependent on p, is found at which sigma(max), the maximum value of sigma in the unstable regime, is largest, with D(0) increasing as p is increased. An asymptotic analysis for small wavenumbers is derived, which enables the region in the (p, D) parameter space for instability to be determined. An analysis for D small is undertaken, which leads to upper bounds on the wavenumber for a possible instability.