单分子膜法测阿伏伽德罗常数实验中扩散剂的新探索

在单分子膜法测阿伏伽德罗常数实验中,为了克服扩散剂苯毒性大且实验误差大等缺点,通过查阅文献资料,发现环己烷、正己烷的物理性质符合在实验中作扩散剂的要求,并且毒性较苯低,所以选用环己烷、正己烷与苯做对比实验。实验结果表明,用环己烷作扩散剂测得的NA最接近理论值。故在用单分子膜法测阿伏伽德罗常数的实验中,环己烷可以代替苯作扩散剂。既能减小实验误差,又可以降低实验过程中有毒药品对实验者的危害。     

负载TiO_2的ACF吸附降解苯的研究

主要研究了负载有TiO2的活性炭纤维(ACF)对苯的吸附降解作用.实验表明:在低浓度实验中,介质质量基本相同的情况下,负载有TiO2的ACF对苯的吸附降解量比无负载的ACF提高11.5%;在高浓度实验中,在苯质量相同以及介质质量基本相同的情况下,负载有TiO2的ACF吸附降解时间比无负载的ACF的时间降低了23%~38%,这说明TiO2在实验中起到了降解苯的作用.     

如何准确把握和使用教材中的实验资源——以苯能否使酸性高锰酸钾溶液褪色为例

针对新课程教材中实验“苯不能使酸性KMnO4溶液褪色”,通过实验探究和文献分析,指出苯与硫酸（或其他非还原性酸）溶液混合均能使KMnO4溶液褪色的事实,并用“苯的环状活性中间体正离子机理”解释了苯被氧化的原因,提出了新课程背景下如何使用和修订该实验的建议。     

二元液系相图实验的改进

在物化实验教材中,二元液系相图的实验,通常选用苯-乙醇体系,此实验设备简单、图形直观.但由于苯的毒性对人体和环境有害,我们用环己烷代替苯.为了减少实验过程中的加料次数,又要使实验点分布合理,我们通过多次实验,摸索出了两组试剂的加料方式:(1)在恒沸仪中注入20 ml乙醇,并依次加入环己烷1,1,2,3,5,5 ml.(2)洗净恒沸仪,用     

苯甲醛Cannizzaro反应的探讨与改进

由苯甲醛Cannizzaro反应合成苯甲酸和苯甲醇实验中，产物苯甲醇在MgSO4和NaHSO4的共同催化作用下发生分子间脱水并高效生成二苄醚。对于苯甲醛Cannizzaro实验的操作步骤提出了改进方法以提高苯甲醇的分离收率。     

石蕊溶液与苯混合后现象的探究

为了研究苯能否从石蕊溶液中萃取出石蕊,通过用相机记录实验现象的方法,对用不同方法配制的3种石蕊溶液与苯混合振荡后经历不同时间后的现象进行研究,发现苯层不能呈现石蕊的颜色,从而得出苯不能从水中萃取出石蕊的结论。     

“苯”的教学设计

1 设计思路(1) 教材分析:人教版《化学2 (必修) 》教材中,对苯的内容编排为:先直接给出苯的分子式和结构式,通过“学与问”栏目引入验证苯结构的实验;再给出苯的物理性质和苯的结构特征:苯分子中的6 个碳原子之间的键完全相同,是一种介于单键和双键之间的独特的键。     

一种快速转移挥发性和腐蚀性液体试剂的实验装置

介绍了一种快速移取液体试剂的实验装置,可用于苯回收连续分馏的实验,解决了连续加料过程中挥发试剂苯对周围环境的污染问题。该装置较好地解决了学生取用具有腐蚀性试剂的安全隐患问题,具有操作简单、方便,安全性能高等特点。     

电感耦合等离子体原子发射光谱法间接测定盐酸苯海索

研究了等离子发射光谱法间接测定片剂中盐酸苯海索含量的方法。详细讨论了ICP AES测定硼的“记忆效应”及最佳测定条件。实验表明在pH 2 .0～ 6 .0范围内 ,当四苯硼钠过量时可完全沉淀盐酸苯海索 ,硝酸铝可以使沉淀迅速絮凝而易于过滤 ,测定滤液中的四苯硼钠可以计算得到盐酸苯海索的含量。该法简单快速 ,相对标准偏差为 2 1%。实验测得盐酸苯海索 四苯硼沉淀的溶度积Ksp在 2 0℃时为8 84× 10 -12     

偶极矩测定的改进

关于“偶极矩测定”的实验,目前国内多用苯做溶剂,测定氯苯或氯仿的偶极矩。这一实验体系中,所用试剂都是毒性很大的易挥发液体。方法本身又决定了在实验过程中有较大的挥发量,所以对人体有害。针对这一情况,我们对“偶极矩测定”实验体系进行了改进,由苯改成环已烷作溶剂,由氯苯或氯仿改成正丁醇作溶质。用此体系测定偶极矩,既可靠又安全。     

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。     

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.     

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.     

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。     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...