固体酸催化合成柠檬酸三甲酯

采用常见的固体酸代替强酸催化合成柠檬酸三甲酯,并通过对固体酸催化活性、用量、反应时间和温度对酯化产率影响的探讨,找到一条固体酸催化合成柠檬酸三甲酯的较佳工艺。     

Bimetallic nanostructures with magnetic and noble metals and their physicochemical applications

Bimetallic nanomaterials consisting of magnetic metals and noble metals have attracted much interest for their promising potentials in fields such as magnetic sensors, catalysts, optical detection and biomedical applications. Bimetallic nanomaterials synthesized by wet-chemical methods with different architectures including nanoparticles, nanowires or nanotubes and their assemblies are summarized in this review. The particular properties of bimetallic nanomaterials, especially their magnetic, catalytic and optical properties, are presented. The advance in electron microscopy makes it possible to understand the nanostructural materials at much higher level than before, which helps to disclose the relationship between the microstructures and properties qualitatively and quantitatively.     

微波消解-催化光度法测定茶叶中的硒

在硫酸介质中,硒（Ⅳ）能催化溴酸钾氧化碱蓝6B使之褪色。研究了这一催化反应的动力学条件,并对茶叶样品进行微波消解处理,建立了一种动力学光度法测定痕量Se（Ⅳ）的新方法。Se（Ⅳ）的含量在4×10^-5-4．8×10^-4μg·mL^-1。范围内与吸光度A呈良好的线性关系,相关系数R为0．9994,样品的回收率为98．9％。该方法测定茶叶中微量硒,所用仪器简单,简便快捷,选择性好,灵敏度高。     

Preparation and catalytic effect of porous Co3O4 on the hydrogen storage properties of a Li-B-N-H system

A porous Co_3O_4 with a particle size of 1–3 μm was successfully prepared by heating Co-based metal organic frameworks MOF-74(Co) up to 500 °C in air atmospheric conditions. The as-prepared porous Co_3O_4 significantly reduced the dehydrogenation temperatures of the LiBH_4-2LiNH_2 system and improved the purity of the released hydrogen. The LiBH_4-2LiNH_2-0.05/3Co_3O_4 sample started to release hydrogen at 140 °C and released hydrogen levels of approximately 9.7 wt% at 225 °C. The end temperature for hydrogen release was lowered by 125 °C relative to that of the pristine sample. Structural analyses revealed that the as-prepared porous Co_3O_4 is in-situ reduced to metallic Co, which functions as an active catalyst, reducing the kinetic barriers and lowering the dehydrogenation temperatures of the LiBH_4-2LiNH_2 system. More importantly, the porous Co_3O_4-containing sample exhibited partially improved reversibility for hydrogen storage in the LiBH_4-2LiNH_2 system.     

动力学光度法测定痕量铁的研究

本文研究了氨水介质中，痕量铁（Ⅲ）催化过氧化氢氧化罗丹明Ｂ褪色的新指示反应及其动力学条件，建立了动力学光度法测定痕量铁（Ⅲ）的新方法。方法的灵敏度为１．８２×１０￣（－１０）ｇＦｅ（Ⅲ）／ｍｌ，测定范围为０—０．８μｇＦｅ（Ⅲ）／２５ｍｌ。用于测定人发及水中痕量铁（Ⅲ），结果满意。     

催化动力学光度法测定痕量钒的新体系

在酸性条件下，溴酸钾氧化铬蓝黑Ｂ的反应，钒具有极高的催化活性，以此建立了测定痕量钒的催化动力学光度法，方法的线性范围为０～２ｎｇ／ｍｌ，灵敏度为１．１１×１０－１１ｇ／ｍｌ，应用于水及人发中痕量钒的测定，结果满意．     

溴酸钾-偶氮胭脂红B体系催化光度法测定痕量亚硝酸根

基于亚硝酸根在酸性条件下对溴酸钾氧化偶氮胭脂红 B褪色的催化作用 ,建立了灵敏的催化光度测定痕量亚硝酸根的新方法 .测定线性范围为 :0～ 0 .5 ug/ m L,检出限 0 .10 ug/ m L 方法灵敏简便 ,选择性好 ,用于测定水中痕量亚硝酸根 ,结果满意 .     

铬（Ⅵ）-晶紫-氧化氢体系催化动力学光谱法测定痕量铬（Ⅵ）

75℃温度下,在硫酸介质中,铬（Ⅵ）能显著催化过氧化氢氧化结晶紫褪色反应,铬（Ⅵ）浓度在一定范围内与催化和非催化反应的吸光度差值（△A）成线性关系,且△A在较长时间内稳定,以此建立起动力学光度法测定痕量铬（Ⅵ）的新方法．实验研究了该反应的动力学行为,确定了最佳反应条件．方法线性范围为0～96μg·L^-1,其线性回归方程为△A=0．0033＋0．1401C（Ⅵ）（μg·25mL^-1）,r=0．9985,检出限为6．91μg·L^-1．本方法操作简单,选择性好,可用于电镀废水、工业废水和湖水样品中有毒金属铬（Ⅵ）含量的分析测定．     

碱性染料在催化光度法中的应用 Ⅰ催化光度法测定痕量锰的研究

本工作较系统地研究了在氨三乙酸存在下,锰(Ⅱ)对高碘酸钾氧化碱性三苯甲烷类、醌亚类染料的催化效应,初步探讨了催化反应的机理,发现了一系列高灵敏度指示反应、检出限为0.1～0.001ng/ml,列出了这些体系的分析特性和部分分析结果。     

减压瓦斯掺入超临界溶剂脱沥青油的催化裂化性能

利用实验室固定式流化床反应装置，考察了将孤岛渣油的超临界溶剂脱沥青油（ＤＡＯ）掺入到孤岛减压瓦斯油（ＶＧＯ）中对其催化裂化反应结果的影响．同时考察了两种裂化催化剂偏Ｙ－１５和ＲＨＺ－２００的不同性能，实验结果表明，掺入量为１０％时，其裂化性能较ＶＧＯ明显地变差；掺入量由１０％增大到２０％，其产品分布的差异表现不很明显，但焦炭产率明显增加，焦炭产率与ＤＡＯ的掺入量近似成直线关系．偏Ｙ－１５和ＲＨＺ－２００裂化性能的差异不很明显，但后者的焦炭选择性好，适用于重质原料．