反应-扩散斑图反应器*

本文综述了在反应-扩散斑图研究中反应器的进展情况。直到20世纪80年代,人们主要在培养皿中研究封闭体系的化学波。为了研究体系在远离平衡态条件下的复杂时空动力学行为,近二十年来人们设计出许多新颖的空间开放反应器(continuously fed unstirred reactor,CFUR)如单边进料反应器(one side fed reactor,OSFR)、双边进料反应器、圆盘形凝胶、圆环形凝胶反应器以及Couette反应器等。反应介质主要为各种凝胶、微孔膜、离子交换树脂以及中孔玻璃。空间开放反应器的设计和发展极大地促进了化学斑图动力学的发展。同时讨论了反应-扩散斑图反应器结构设计遇到的困难如气泡和三维效应,并且对反应器设计与斑图研究未来发展方向进行了探讨。     

对数浓度图在分析化学教学中的一些应用(下)

三、络合物的对数图及其应用 1.金属-EDTA络合物的对数图与络合滴定曲线 以10-2MEDTA(Y)滴定10-2MCa2+为例,图8是其络合物对数图与滴定曲线的并联图(虚线表示pH为8,实线表示pH为11)。     

冠醚配合物的热力学性质的研究(Ⅰ)——若干金属离子与18-冠-6及其甲基衍生物的配位反应的量热滴定研究

量热滴定法是研究冠醚的溶液配位化学的重要方法,一次滴定可同时求出稳定常数K和反应焓△H,而且是测定后者唯一直接而准确的方法,Izatt[1-3]等作了大量的研究。但因量热滴定需要精细的操作,且计算复杂,故应用此法的实验室不多。在我国,用量热滴定法于溶液配位化学的研究似未见报道。     

氧化还原滴定的终点误差图及其应用

在滴定分析中,用误差图来讨论与终点误差有关的问题十分方便。例如,络合滴定的误差图,清楚地反映了TE、K_(ML)、ΔPM和C_M四者之间的关系,若知其三者,可由图求出其四来。孟凡昌等移用络合滴定误差图讨论了最简单的氧化还原滴定终点误差问题,即参加反应的两个电对都是对称性电对,且滴定剂的n_T等于被滴定剂的n_x的情况。我们曾提出一个适用于各种氧化还原滴定终点误差的公式,本文以此为基础,得到一个氧化还原滴定的终点误差图(见图1),表示终点误差TE、终点与等当点pe值之差Δpe及等当点pe_(eq)与被滴定剂克式量pe~0之差Δpe~□三者的关系。利用该图可以进行各种复杂情况的氧化还原滴定终点误差问题的讨论。     

等温稀释型量热计的建立和过量焓的测定

本文建立了一套等温稀释型量热计, 该量热计可用于吸热型体系过量焓的测定,量热计灵敏度为2μV.J^-^1, 恒温精度为±8*10^-^3K。经环己烷-苯体系和环己烷-正己烷体系在298.15K时标定, 精确度在15%以内, 测定了缔合体系在乙醇 -苯体系303.15K时溶液的过量焓。     

用5-Br-PADAP为指示剂络合滴定镍

作者使用高灵敏度的显色剂2-(5-溴-2-吡啶偶氮)-5-二乙氨基苯酚(5-Br-PADAP)作指示剂,于pH_4.0～5.5醋酸盐缓冲的热溶液中,用EDTA络合滴定镍,滴定终点突变明显,溶液颜色从紫红变为浅黄。故5-Br-PADAP可作为在微酸性介质中直接络合滴定镍的新指示剂。实验表明:Ca~(2+)(10毫克、下同,并非最大允许量)、Mg~(2+)(10)、六偏磷酸钠(100)、硫脲(5000)、氟化钠(2000)、苦杏     

近年物理化学滴定进展

评述了近五年国内外物理化学滴定（用作图确定终点）的新进展，内容包括：（１）光学滴定（含光度、荧光、磷光、化学发光滴定）；（２）电滴定（含电位、电导、电流、库仑滴定）；（３）量热滴定。每类滴定均再按滴定用介质分为水介质和非水介质滴定，按滴定反应分为酸－碱、氧化－还原、络合、沉淀滴定，按滴定方式分为直接滴定、代滴、回滴。引用文献１０６篇。     

络合体系中的相对滴定法及其应用于铝的测定

本文提出了络合体系中的相对滴定分析法，它以滴定到一定的状态时，滴定剂体积与被测物的基之间的线性关系为定量基础，用仪器分析的定量方法进行定量，适应于所有类型的络合体系，即使对滴定突跃很小或根本无突跃的体系也同样适用。用氟离子滴定铝离子的实验结果表明本方法的精密度很高。一般相对误差小于0．1％。即使对于铝离子的量小到10-7mol／L时，在最佳实验条件下的相对误差也不大于0．2％。该方法既具有滴定分析法的高精密度，又具有仪器分析法可以测量微量物质的优点，并且设备和方法简单。     

P204Li在有机相形成反向胶束过程的微量量热法研究

滴定微量量热法;P204Li在有机相形成反向胶束过程的微量量热法研究;热力学函数;临界胶束浓度;溶剂萃取;临界胶束浓度;     

对数图在氧化还原滴定中的应用

Wanninen和Jahansson将对数图用于酸碱滴定和络合滴定,能巧妙地解析一些问题。Silleen曾作过氧化还原反应的对数图解,但未应用于氧化还原滴定。本文试就对数图在氧化还原滴定中的应用及滴定误差问题进行一些讨论。一、氧化还原滴定中的对数图在氧化还原反应中,我们如将能斯特公式加以变换,可得     

一套恒温环境连续式滴定量热装置的建立及其热谱图分析方法的改进

根据滴定量热原理,结合国内实际建立了一套恒温环境连续式滴定量热计。经各种物理性能测试表明,仪器运行稳定可靠,灵敏度为9.91×10^-5kmm^-1,经化学标定(HClO₄+NaOH)测得△H_N⁰=-13.341±0.0181kcalmol^-1。用本仪器测定银(Ⅰ)-吡啶两级配合物的稳定常数和生成焓,结果与文献值吻合。     

New Isothermal Titration Calorimeter for Investigations on Very Small Samples. Theoretical and experimental studies

A new isothermal titration calorimeter with 78.5 μL volume capillary chambers has been developed. It is based on the theory of mixing reagents in a capillary chamber of a titration calorimeter and separation of the sensitive volume of chambers in a differential calorimeter. The evaluation of the efficiency of diffusion mixing is described by means of an oscillating dispensing needle. The calorimeter was tested by the reactions: Ba²⁺– 18-Crown-6 and Rnase-2’CMP. The main advantages of the new titration calorimeter are the use of very small amounts of reagents, the high accuracy of separating the sensitive volume of calorimetric chambers and the minimization of power input while mixing reagents in a horizontally located capillary chamber. This revised version was published online in August 2006 with corrections to the Cover Date.     

气体流动热量计和苯、苯-环已烷气体热容的测量

A set of vapor-flow calorimeter has been constructed on the basis of Power's adiabatic calorimeter and Clarke s flash boiler. It can determine the heat capacities of mono-or multi-component vapors from vaporizing temperature to 600 K and 10—600 kPa pressures. For the calibration of the instrument, the heat capacities of benzene have been measured under 51.1, 101.3, 309.3 and 495.2 kPa and 370—600 K tempera-tures. For multicomponent vapor, benzene-cyclohexane has been determined. The results showed that the calorimeter has both the precision and accuracy better than 1.0% for either pure or mixtural vapors.     

模拟合成盐卤与盐酸反应的热化学研究

青藏高原新类型盐湖卤水日晒蒸发过程中硼酸盐在浓缩卤水中富集L‘。，我们在前又问中曾报道天然浓缩盐卤中硼酸盐是以“四硼酸盐”的综合统计形式存在，当盐卤浓缩到氯化镁共饱和时，可视为MgO－BZO3－MgC12－HZO四元体系中的一个特定的膺三元体系MgO·2B2O3－MgC12－H。O．该四元体系20oC热力学非平衡态液固相图问与25oC热力学平衡态相图＊存在较大差别．由于聚合翻氧配阴离子的存在，使得对含棚浓缩盐卤的研究变得复杂而困难＊．李积才等“～SJ对合成盐卤的稀释热和表观摩尔热径进行过测定，李军间在对多种水合硼酸盐在盐酸中…     

N,N'-(对位取代苯基)乙二胺的质子化及其与Cu(Ⅱ)配位的滴定量热测定

The apparent thermodynamic functions of the protonation and coordination of N,N′-(para-substituted phenol) ethylenediamine with Cu (Ⅱ) has been determined at 25.0±0.1 ℃ and I=0.1 mol.dm~(-3) (NaClO_4) in 90% (V/V) ethanol by the constant temperature environment-continuous titration calorimeter which had been constructed in our laboratory. It has been found that the heat of protonation (H_(L1)) is linearly correlated with the Hammett constants and the formation of H~+ bridge occurs in ~H+ -N, N′-(p-RPh)_2en (1:1) systems.     

Modulated capillary titration calorimeter

A modulated capillary titration calorimeter has been developed. New software and optimization of the calorimetric unit CTD2156 are used as a basis of the modulated capillary titration calorimeter. The scanning mode of the calorimeter has been theoretically substantiated. The scanning of chambers temperature is provided due to the fact that the shield temperature is linearly varied at heating and cooling. The reversing and kinetic part of the total heat flow are measured at heating of a diluted collagen solution. The main advantage of the calorimeter is its ability to operate in a modulation mode, in an isothermal mode, in modes of linear heating and cooling of homogeneous and dispersoid liquid samples at an effective mixing of reagents in calorimetric chambers.     

Heat conduction effects during the calorimetric determination of absorbed dose to water in radiotherapy beams

A transportable water calorimeter for the determination of the quantity of absorbed dose to water in radiotherapy beams has been developed at the PTB and is presented in detail in this investigation. Heat conduction effects occurring in the calorimeter are studied for different lateral sizes of high-energy photon beams, for different depth dose distributions of electron beams and for a scanned-beam irradiation with a heavy ion beam. The corresponding correction factors are calculated and arguments are given under which conditions these can adequately be applied.     

Studying dispersoid systems

Summary Measurements of energy transformation in mitochondria are done on a capillary differential titration calorimeter CTD2156. It is important to mention that a sediment is quickly formed by the mitochondria suspension without mixing by means of a vibrating needle. During the measurements, the vibrating needle is located inside the working volume of the chamber. The design of the calorimeter is substantiated theoretically. It provides a new mode of a reagent input in the measuring volume of the calorimetric chambers. It expands the spectrum of tasks that can be solved using this instrument. In the capillary calorimeter the calorimetric chambers unit is simple and small in size. These advantages of capillary chambers provide an opportunity to unite 20 capillary calorimetric chambers in one calorimetric block. It allows designing a multi-channel titration calorimeter. There are obvious advantages of such a calorimeter over other instruments in screening researches and in researches of objects maintaining stability only for a short time.     

Design of software for thermal titrations

A set of computer programs has been written in FORTRAN and in BASIC to allow automation of data acquisition from a TRONAC titration calorimeter and calculation of the concentration of titrant or titrand in an acid-base reaction; the heat capacity of a solution and enthalpies of reaction may also be calculated. The enthalpy change of a reaction and equilibrium constant can also be determined under certain conditions.