卤代苯和卤代萘用三氧化硫进行的磺化反应

本文研究 了在非极性溶剂二氯甲烷中卤代苯和卤代萘用SO~3进行的磺化反应. 卤代苯最初开始磺化反应的产物是4-磺酸, 2-卤代萘的产物是8-磺酸. 当用过量的SO~3长时间反应时, 磺化反应得到三取代产物.     

卤代苯和卤代萘用三氧化硫进行的磺化反应

前文报道了各种甲氧基萘用三甲硅基氯磺酸酯在非极性溶剂中进行的磺化反应。本文研究了四种卤代苯和六种卤代萘用三氧化硫在非极性溶剂中进行的磺化反应。卤代芳香化合物用氯磺酸,浓硫酸及发烟硫酸进行的磺化反应已有报道。在芳香化合物的亲电取代反应中,卤素的定位效应取决于以下两个因素。首先,负的诱导效应体现为F>Cl>Br>I,且对邻位的影响远大于对位的影响。而正的共轭效应亦体现为F>Cl>Br>I,对对位的影响最大。单取代卤苯在浓硫酸中进行磺化反应,几乎专一地发生在4—位上。说明尽管卤素降低了芳香环上的电子云密度,但仍为邻对位定位基。三氧化硫(SO_3)是最剧烈的磺化剂,溶于非极性溶剂二氯甲烷中,既减少了付反应,又可在室温下进行高效率的磺化反应。     

卤代异羟肟酸钴（Ⅱ）配合物催化氧化二甲苯的研究

以空气为氧源,一系列卤代异羟肟酸钴(Ⅱ)配合物(CoL21～CoL29)为催化剂,研究了其液相氧化对二甲苯生成对甲苯甲酸的性能和规律,比较了配合物中引入卤原子的种类与位置对催化剂催化活性的影响,考察了氯代异羟肟酸钴(Ⅱ)配合物CoL23催化氧化不同配比的混合二甲苯的选择性.结果表明:在反应温度为110℃、催化剂浓度为1.0 mmol/L、空气流速为2.4 L/L/min的条件下,1.5 h内二氯代异羟肟酸配体的钴(Ⅱ)配合物的催化活性顺序是CoL23＞CoL24＞CoL27＞CoL25＞CoL26,1.5～4 h的催化活性顺序是CoL23＞CoL24＞COL24＞CoL25＞CoL26单卤代异羟肟酸配体的钴(Ⅱ)配合物催化活性顺序是CoL29＞CoL28＞CoL21.当混合二甲苯中各异构体比例为5:3:2(对:邻:间)时,反应有较高的选择性,并能析出纯度达96.7%的对甲苯甲酸固体.     

卤代苯与水分子间作用的从头算

污染是科学家关注的热点问题,化学污染物是造成水污染的重要因素［１］．在水环境中,卤代苯是一类优先污染物（ｐｒｉｏｒｉｔｙｐｏｌｕｔａｎｔｓ）［２］．这类污染物毒性大,在环境中的半衰期长,美国环保局（ＥＰＡ）已经把它们列入优先污染物之列．Ｖｅｒｓｃｈｎ...     

海沙钛铁矿在硫酸溶液中的电化学溶解研究

采用电化学技术研究了孟加拉国海沙里钛铁矿在硫酸溶液中不同温度下的溶解行为. 循环伏安研究表明,在没有添加碳粉的条件下钛铁矿的溶解非常困难. 为了探明钛铁矿的溶解过程,考察了钛铁矿-碳比例、硫酸浓度和温度对钛铁矿电化学溶解行为的影响. 结果显示,钛铁矿在低还原电位和低温下的溶解速率较慢. 施加更负的还原电位和在较高的温度下溶解速率加快. 增加硫酸浓度（最大浓度到1 mol?dm^-3）也可提高溶解速率. 但是,在较高的硫酸浓度和还原电位下,由于氢气析出导致钛铁矿的溶解速率降低,且气体吸附最后使得钛铁矿的活性表面积减小. 计算得到活化能数值在高温区间为50±10 kJ•mol^-1, 而低温区间为?15±5kJ•mol^-1, 说明低温区间为扩散控制过程,而高温区间为化学控制过程.     

非完全汽化气相色谱法测定溶剂型涂料中的微量苯、甲苯、二甲苯

用乙酸乙酯稀释溶剂型涂料样品，在较低的汽化温度下直接进样，溶剂型涂料中未汽化的组分留在汽化室里，而苯、甲苯和二甲苯汽化后进入毛细管，用气相色谱法氢火焰离子化检测器进行检测，与国家标准分析方法进行比较，该法具有操作简单、精密度高等优点。     

卤代苯溶剂对镓咔咯配合物光物理性质的影响:外重原子效应

利用紫外-可见光谱、稳态和时间分辨荧光光谱以及飞秒瞬态吸收光谱探测了不同卤代苯溶剂对三种五氟苯基取代的镓咔咯(1-Ga、2-Ga、3-Ga)光物理性质的影响,结果表明卤代苯溶剂的色散力对于镓咔咯电子光谱吸收峰位置的影响起着主要作用;溶剂外重原子效应能显著降低镓咔咯的荧光量子产率。飞秒瞬态吸收光谱表明,光激发下,镓咔咯与卤代苯溶剂之间可发生电子转移反应,溶剂的重原子效应可以减缓电荷分离态复合物电荷重组速率。     

气相色谱法快速同时测定室内装饰装修材料胶黏剂中的苯、甲苯、二甲苯的含量

建立了快速、同时测定室内装饰装修材料胶黏剂中苯、甲苯、二甲苯含量的气相色谱检测法.样品用乙酸乙酯溶解处理后,用改性的聚乙二醇(FFAP)毛细管色谱柱分离,氢火焰离子化检测器检测,外标法定量.胶粘剂中苯、甲苯、二甲苯的浓度分别在8.58～171.40μg/mL、9.04～180.62μg/mL、8.80～175.92μg...     

卤代苯和苯酚衍生物的位电荷密度能和1og Kow与-lg LC50的QSAR研究

以简易的量子化学方法计算了二十多种卤代苯和苯酚衍生物的FMO位电荷密度能,并进行定量结构-活性相关(quantiktive struvyitr biodegradability)研究,获得满意的结果.最后从生物酶促反应本质、污染物-生物酶的轨道控制反应角度对QSAR提出新的解释.     

钐试剂在合成中的应用 Ⅰ.金属钐作用下烯丙基和苄基卤代物与羰基化合物的反应

本文研究了金属钐作用下的Barbier型反应。结果表明,经氯化汞活化的金属钐对酮类化合物与烯丙基或苄基卤代物的反应很有效,可高产率地生成叔醇。此反应有很好的区位选择性和化学选择性,与α,β-不饱和酮的反应未发现1,4-加成产物生成,与环上有卤素(Br,Cl)取代的芳香酮反应,取代基不受影响。产物的形成可能通过了有机钐中间体。     

几种固态芳烃与银离子配合物形成常数的测定

作者曾报道用溶质蒸气循环方式制备液态芳烃的饱和溶液,测出苯、甲苯、二甲苯、卤代苯等液态芳烃在水和硝酸银体系中的溶解度,并计算了上述芳烃与Ag~+配合物的形成常数。 具有C=C双键的许多固态芳烃也象液态芳烃一样可与银离子形成配合物,我们设计了溶质蒸气循环方式制备固态芳烃的装置,该法的最大特点是固态溶质和溶剂不直接接触,可以避免固态溶质颗粒在溶剂中的分散和容器壁上的吸附现象,因此用本法测定的溶解度和配合物的形成常数数据可靠、精确。     

Isentropic Compressibility,Shear Relaxation Time,and Raman Spectra of Aqueous Calcium Nitrate and Cadmium Nitrate Solutions

Speed of sound, viscosity and Raman spectra of aqueous calcium nitrate and cadmium nitrate solutions were measured as functions of molality and temperature. The isentropic compressibility isotherms for both systems cross over in a narrow molality region. In comparison with Ca(NO₃)₂(aq) solutions, Cd(NO₃)₂(aq) solutions have lower isentropic compressibilities due to a lower charge to radius ratio. The observed Raman spectral changes in the ₃ (1400 cm^–1) and ₄ (700 cm^–1) modes with an increase in molality suggest that the symmetry of NO₃^– changes from D_3h to C_2v, and solvent-separated and/or solvent-shared ion pairs are formed in both systems. The results from plotting electrical conductivity versus shear relaxation time also imply that the influence of the solvent-separated and/or solvent-shared ion pairs begins 2.0 mol-kg^–1 for these systems. The larger values for the ₃ mode for Cd(NO₃)₂(aq) solutions indicate stronger solvent-separated and/or solvent-shared ion pairs formation in comparison to Ca(NO₃)₂(aq) solutions.     

Solubilities and partial molar enthalpies of solution for polar gas-liquid systems determined by gas chromatography

Summary The gas-liquid chromatographic method has been used to determine the solubilities and partial molar enthalpies of solution of the gases H₂S, CO₂ and COS in four polar solvents. The results agree well with literature values obtained using conventional techniques, with the one exception of H₂S in N-methyl-2-pyrrolidinone. In this case there is some evidence for the occurrence of adsorption at the gas-liquid interface.     

1,2—双[烷基（芳基）硫代]乙烷对银的萃取及其配合物

本文研究了1,2-双(正-丙基硫代)乙烷(BPrTE)、1,2-双(正-戊基硫代)乙烷(BATE)、1,2-双(正-辛基硫代)乙烷(BOTE)和1,2-双(苯基硫代)乙烷(BPTE)对银的萃取.讨论了硝酸浓度、稀释剂RS(CH_2)_2SR(L)中R基因对萃取银的影响.L可从大量贱金属和氯化物中定量地萃取银,银和配体可形成组成为Ag:L=2.5:1,2:1,3:2,1:1,2:3,1:2系列配合物.     

双波长分光光度法同时测定溶液中的硝酸根和碘离子

食品和环境样品中往往同时含有硝酸根和碘离子,用紫外分光光度法直接测定硝酸根或碘离子时,二者相互干扰。为此建立了主、次波长分别为220.0、231.5 nm的等吸收点双波长紫外分光光度法测定溶液中的硝酸根和共存的碘离子。当溶液中硝酸根的浓度在0~0.12 mmol/L的范围内,碘离子的浓度在0~0.10 mmol/L的范围内时,主、次波长下的吸光度差值A220-231.5与溶液中硝酸根的浓度 呈良好线性关系,线性方程为A220-231.5 = 2.9958 0.0016（R2 = 0.99994）;其中A220 (NO3-) = 3.6099 0.0084（R2 = 0.99994）,利用吸光度的加和性：A220 (I-) = A220 - A220 (NO3-) = 10.7394 0.0029（R2 = 0.99994）,间接得到碘离子含量 。硝酸根和碘离子的平均相对标准偏差分别为0.6%、0.2%,回收率分别为99.5~102%、99.9~100%。方法简便快捷,可用于溶液中微量硝酸根和碘离子的同时测定。     

Effect of the Type of Glycosidic Linkage on the Selective Interactions of Maltose and Cellobiose with Some Crown Ethers in Dilute Aqueous Solutions

Titration calorimetric and densimetric measurements have been applied to study the selective interactions of two disaccharides composed of two glucose units, maltose and cellobiose, with 15-crown-5 and 18-crown-6 in dilute aqueous solutions. Maltose and cellobiose form thermodynamically stable complexes with different stoichiometries with 18-crown-6 but not with 15-crown-5. The obtained results are explained by the different states of the disaccharides in aqueous solution due to effect of the type of linkage between glucose units     

硝酸胺溶液浸提硬硼酸钙的动力学研究

对硬硼酸钙在硝酸铵水溶液的溶解在间歇式反应器中就搅拌速度、粒径大小、反应温度、固液比和溶液的浓度等参数的影响进行了研究。结果表明溶解速度随温度、硝酸铵水溶液的浓度以及粒径和固液比的增加而增加,但搅拌速度对溶解速度无重要影响。硬硼酸钙在硝酸铵水溶液中可以高达100%。硬硼酸钙的溶解动力学根据多相和均相反应模型进行了检验。实验数据表明有高的活化能,说明基于多相反应动力学模型的溶解速度可表达为：1-(1-X)^1/3=3.28 ×10⁴·D^{-0.653 7}·C^{1.295 8}·(S/L)^{-0.490 9}·e^-41.40/(RT)·t。反应过程的活化能为41.40 kJ·mol^-1。     

Fluorimetric Determination of Silver with Brilliant Green in Aqueous Systems and its Application in Photographic Fixing Solutions

Abstract

A fluorimetric procedure for Ag⁺ determination in aqueous solutions was developed based on the ion association complex formed from the reaction between AgI^- ₂ and the brilliant green cation and its strong fluorescence (λ_exc 256 nm, λ_em 521 nm). Silver ions could be determined satisfactorily in the range of 0-100 μgAg⁺/L. Optimum conditions for complex formation and measurement of fluorescence intensity were: pH = 3.0; concentrations of brilliant green and KI, 15 and 100 mg/L, respectively; time, within 15 min after complex formation. The method proved successful in determing Ag⁺ in photography fixing solutions and the results agreed satisfactorily with those obtained using a standard Atomic Absorption Spectrometry method.     

Preparation and Thermal Chemical Property of Complexes of Zinc Nitrate with Trytophan

IntroductionZincisanessentialtraceelementtothelife .Manydiseasesarousedfromadeficiencyofzincelementhavere ceivedconsiderableattention .L α Aminoacidsarebasicunitsofproteins .L α Trytophanisoneoftheeightspeciesofaminoacidsindispensableforlife ,whichhastobeab sorbedfromfoodbecauseitcannotbesynthesizedinthehumanbody .InviewofthecomplexesofL α trytophanandessentialelementsasaddictiveswidelyusedinsuchfieldsasfoodstuff,medicineandcosmetic ,1 3theyhaveabroadenprospectforapplications .Briefly ,ab…     

四元交互体系Li+，K+/CL-，CO2-3-H2O在298 K时相平衡及物理化学性质研究

Zabuye Saline Lake, Tibet, China, is unrivalled in the world for its very high salinity, in particular, for the very high concentration of ions of lithium, potassium, and boron in the brine. It belongs to alkaline and carbonate-borate-type salt lake. As a part of the study on phase equilibrium of the 6component subsystem Li+, Na+, K+/C1-, CO2-3, B4O2-7-H2O of the brine system, a study on the reciprocal quaternary system Li+, K+/C1-, CO32-H2O at 298 K was done with isothermal dissolution equilibrium method in the present work. The phase equilibrium of the reciprocal quaternary system Li+,K+/C1, CO2-3-H2O at 298 K was studied with isothermal dissolution method in this work. The physicochemistry properties of the corresponding equilibrium solutions such as densities, viscosities, refractive index, conductivities and pH value were determined. The dried salt diagram of the system consists of four crystallization fields (KC1, Li2CO3, LiCI·H2O, K2CO3·3/2H2O) and five isothermal solubility curves.There are no double slat or solid solution found. Pitzer′s model of the electrolyte solution theory was used for parameterization from the results of solubility determination for subsystems and the prediction of solubilities for the reciprocal quaternary system was made. The solubility data of the experiment are in agreement with those calculated.