水中溶解氧的微量滴定

将微量滴定技术应用于常规的碘量法测定水中溶解氧。在实验中采用了WD-CO3型微量滴定装置，并使用自行设计制成的高精度微量移液管（移液的体积可准确至0．001mL），作为转移标准溶液及试样溶液的工具。对微量滴定及微量移液与常量滴定和常量移液作了对比试验，结果表明两者的分析结果完全吻合，微量滴定（其中包括微量移液）所得结果的精密度也在定量分析允许范围之内。由此，微量滴定技术应用于水中溶解氧的日常分析的可行性得到了验证。     

一种新型光度探头的研制及铁的自动光度滴定

光度滴定不但能滴定常量物质,而且也能准确滴定浓度<1×10~(-5)mol·L~(-1)的微量物质.但目前光度滴定的应用还不很广泛,其主要原因在于,光度滴定计量点的判断一般要借助于分光光度计、液体循环池,并由绘制滴定曲线求得,相当麻烦.我们利用最大透光度570～600nm的黄色滤光片、小钨灯、光敏二极管,制成了一种高灵敏度的光度探头.配合MX-5型多功能化学分析仪,实现了自动光度滴定,并用于铁的测定取得了满意的效果.1 主要仪器与试剂     

水中硫酸根及其总硬度的EDTA滴定法——采用计滴微型毛细管滴定管

用EDTA微量滴定法测定了水中硫酸根及总硬度，测定过程在氨性缓冲介质中进行，采用络黑T作指示剂，用一种自制的聚乙烯微型毛细管滴定管进行滴定，滴定反应所耗的滴定剂用计滴法计数。从微滴管流出的每一小滴滴定剂的体积（通常在0．01～0．02mL之间）用重量法校正，每次滴定所耗滴定剂一般在50～200小滴之间。此方法的扩展不确定度，对硫酸根测定为0．94％与重量法相当，而精密度则优于重量法，对总硬度测定为0．82％优于常量滴定法。此方法的特点为分析快速、准确，消耗试剂少且便于携带，适合于现场或野外分析应用。     

示波库仑滴定

示波滴定的理论和实际应用近几年来发展较快,但过去的工作多限于常量分析。库仑滴定可获得较高的准确度和灵敏度,但常常因缺乏简便、灵敏的终点指示方法而使其应用范围受到限制。若将这两种方法结合起来,则既可弥补库仑滴定法的不足使滴定终点变得简单直观,又可使示波技术用于痕量分析。本文报道两铂电极示波电位滴定终点指示技     

催化滴定分析法的现状及进展

催化滴定是利用催化反应指示滴定终点的一种滴定分析方法，它兼具催化动力学分析法的高灵敏度和经典滴定分析法高准确度的特点，既适用于常量分析又适用于微量分析。此文就催化滴定在研究和应用方面的进展作出概述。     

虹吸进液自动校准两用滴定管

本文设计了一种由一支常量滴定管、一支微量滴定管和校准管组成的连通器(图1),根据同一种液体在连通器里液面保持一定高度的原理,采用校准管来控制常量滴定管和微量滴定管内溶液的高度。操作溶液采用虹吸装置与连通器相联。这样,组成了一个可作常量滴定和微量滴定的装置,使用方便,也提高了分析精度。     

非水滴定测定α氨基酸含量实验的微型化

以电位滴定为基础，确定指示剂终点变色，并进行了常量和微量方法对比。实验中以冰乙酸为溶剂，用0．1mol／L高氯酸的冰乙酸溶液为滴定剂，以结晶紫作为指示剂，对新合成的甘氨酸和久置异白氨酸进行了测定。     

铜滴定分析的进展

由于铜在工业、农业、国防、科研及首饰等领域中都有重要的应用,因而有关铜的分析,人们作了相当广泛的研究,其中常量的铜多以滴定法进行测定,尽管已有的几种主要滴定反应基本定型,方法及技术已比较成熟,但近年来,国内外仍在研究新的指示剂、滴定剂、掩蔽剂、新方法与新技术,使铜的滴定分析不断发展与完善。本文着重评述1989～1994国内外在铜滴定分析方面有意义的研究工作进展,还引用少数1989年以前的文献。 1 新方法与新技术 在准确滴定诸如紫铜一类的高含量物质量时,产生滴定误差的主要原因是滴定管的最小加入量及准确读数的限制,为了满足紫铜分析的误差要求(≤0.03％),必须设法扩大滴定管的“量程”以提高滴定分析的分辨率和准确度。为此,袁秉鉴在研究“百实量计     

一种自动微量滴定新方法

本文依据传统滴定分析原理，利用流动注射装置提出一种新的自动微量滴定方法，它不仅具有流动注射滴定分析法简便快速，试剂和试样消耗少，仪器装置简单等优点，而且测定信号怀被测组分的浓度直接成线性关系，结果的准确度和精度优于一般流动注射滴定方法。通过用盐酸滴定氢氧化钠进行验证，相关系数为０．９９９９，相对标准偏差（ＲＳＤ）为０．４％。     

利用微量仪器莫尔法测定氯的含量

介绍以微量仪器测定氯的含量以及标准AgNO。溶液的配制和标定。该测定方法采用WD—COII型微量滴定管,所得结果与常量容量仪器滴定一致。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.