分光光度法测定水溶液中三碘络离子的生成常数

应用分光光度法,研究了水溶液中碘和碘离子反应生成三碘络离子的平衡。当碘的总浓度c_I相同时,通过测定I_2-KI稀溶液的吸光度A随碘离子的总浓度C_I-的变化,根据吸光度的加和原理和A与C_-的非线性函数关系,在PC-1500微机上用非线性函数的最小二乘曲线拟合A与C_I-数据,得到298K时三碘络离子生成反应的平衡常数K为805.8,298K 460nm时碘和三碘络离子的摩尔吸光系数eI 和cI-分别为742.8和1102L·mol~(-1)·cm~(-1)。方法操作简便,结果准确,摒弃了不必要的假定。对水溶液中存在数种有色物质的简单平衡体系,该法可方便地测得反应的平衡常数,各有色物质的摩尔吸光系数及各物质的平衡浓度。     

Macrocyclic compound as ionophores in lead(Ⅱ) ion-selective electrodes with excellent response characteristics

Macrocyclic compounds,such as crown ethers,azacrown ethers,thiacrown ethers,calixarenes and porphyrins,which act as ionophores in lead(Ⅱ) ion-selective electrodes,are systematically summarized based on the latest literatures.The molecular structure characteristics of the ionophores are general-ized.The modification regulations for the substituted ionophores are elaborated with the purpose of improving the response features of the lead(Ⅱ) ion-selective electrodes assembled by them.It is pointed out that the introduction of pendant moieties which contain soft base coordination centers like N,S and P atoms is in favor of adjusting the cavity size and conformation of the macrocyclic com-pounds.Furthermore,there is synergic effect between the cavity and the donor sites of the ligand and thus the selective complexation of lead ions is easily realized,resulting in significant avoidance of the interference from other metal ions.The macrocyclic ionophore having the best response characteris-tics thus far was found to be N,N'-dimethylcyanodiaza-18-crown-6 with the detection limit of 7.0×10-8(14.5 μg/L),which is one of the uncommon ionophores that can really eliminate the interference from silver and mercury ions.The selectivity coefficients of the ionophore for lead ions over other metal ions,such as alkali,alkaline earth and transition metal ions are in the order of 10-4 or smaller,where the se-lectivity coefficient of lead(Ⅱ) over mercury(Ⅱ) ions is much lower,down to 8.9×10-4.The structure de-sign idea for high-performance ionophore is proposed according to present results.The incorporation of nitrogen atom,especially cyano group or thiocyano group or amino/imino groups,rather than thio atom alone could result in new excellent lead ionophores.The aborative design for metacyclophanes containing aromatic nitrogen atoms with the aim of creating excellent ionophores would also become a potential research trend.The lead(Ⅱ) ion-selective electrodes have shown widely potential applications in the potentiometric titration,and flow injection potentiometry,and in the direct determination of lead in stack emissions of lead smelters,and assay of lead in rocks,particularly in the direct measurements of trace amount of lead(Ⅱ) in human hair,blood,edible oil,food,water,and air.     

离子交换树脂催化合成乙酸叶醇酯的研究

本文选用不同型号的苯乙烯系阳离子交换树脂对叶醇的乙酰化反应进行催化， 合成出调香用香原料乙酸叶醇酯， 此外对催化剂的种类以及用量、醇酐比、反应时间等因素进行讨论， 产物最佳收率为９３ ％ ．     

抑制型离子色谱法同时测定矿泉水中阴离子的研究

基于化学自动再生抑制型离子色谱电导法,以2.0 mm ol.L-1N a2CO3+1.3 mm ol.L-1N aH CO3+2%CH3COCH3做淋洗液,选择了最佳色谱条件,在10.5 m in内一次进样测定了矿泉水中F-、C l-、NO3-、SO42-4种主要阴离子。测定样品的相对标准偏差(RSD)为2.59%~5.83%,样品回收率在90.6%~107%之间。采用化学抑制模式的离子色谱法是检测矿泉水中阴离子的快速、准确的方法。     

离子束蚀刻硅片沟槽台阶形貌研究

1 离子束蚀刻实验 1.1 样品制备取机械抛光的N型单晶硅片(1,1,1)作蚀刻样品,均匀涂上厚度为1μm的OMR-83光刻胶,利用集成电路制版技术,用曝光方法将光刻胶刻出宽度分别为15μm,10μm,5μm,长为2mm的长槽。     

353E树脂提取金的研究

通过对几种树脂比较后发现，在氯化溶液中３５３Ｅ树脂对金量种较为理想的吸附剂，考察了溶液中金含量，酸度、氯离子浓度等因素对３５３Ｅ树脂吸附金的影响，酸度，硫脲浓度，温度等对硫脲解吸金的影响，在适宜条件下，金的吸附率和解吸率都在９８％以上。     

离子交换法制备LiMn1-chCoxO2及其电化学性能

采用离子交换法制备出层状结构锂离子电池正极材料LiMn1-xCoxO2（0．1≤x≤0．5）。X射线衍射和扫描电镜进行分析表明材料具有明显的层状结构和良好的结晶性。电化学性能研究表明，LiMn0.5C0.5O2的最高放电容量为175mAh／g，并且具有良好的循环性能，在3．0～4．5V的冲放电电压范围内，经过20次循环，可逆容量达95％。对实验结果的研究表明，随着Co含量的增加，材料具有更明显的层状性能和更优的循环性能。     

溶胶-凝胶法制备层状LiMn0．5Ni0．5O2锂离子电池正极材料及其电化学性能

以醋酸锂、醋酸锰和醋酸镍为原料，羟基乙二酸为螯合剂，通过溶胶-凝胶法制备层状LiMn0．5Ni0．5O2正极材料，得到的产物具有典型的α-NaFeO2层状结构，颗粒尺寸在300-400nm之间。对900℃下制得的层状LiMn05Ni0．5O2在2.5-4．3V之间进行充放电测试，电流密度为0．1mAcm^-2，其首次放电容量达到了161．2mAh g-^1。经过20次循环后，仍然保留了初始容量的88％。     

阿霉素金属配合物及其与氨基酸的作用

采用紫外－可见光度法和荧光光度法研究了ｐＨ７．０条件下,阿霉素与金属离子,生物小分子的相互作用。结果表明,Ｆｅ＾２＋,Ｃｕ＾２＋与阿霉素可形成稳定的配合物,Ｍｇ＾２＋,Ｎｉ＾２＋,Ｃｏ＾２＋与阿霉素有较弱的相互作用,在氨基酸存在下,Ｃｕ－ＡＤＭ配合物发生解离,而Ｆｅ－ＡＤＭ相对较稳定。