倒数示波计时电位法的研究: 新线路的研制及应用

本文研制了获得倒数示波计时电位图的新线路, 并加上电流反馈装置。这套装置具有灵敏度高、稳定性好等特点, 应用此线路, 我们用新的方法进行了峰电位的测量、痕量物质的分析及药品含量测定。     

甲酸氧化反应动力学反应装置的改进

进行甲酸氧化反应动力学实验时,需要在反应前用去离子水清洗反应装置内壁。由于原反应装置（图1）存在缺陷,反应装置口使用橡皮塞,反应装置底部无活塞,每次换液时,需取出橡皮塞,倒出废液,洗净后再放回,操作不方便,而且容易损坏反应装置。在实验时,要将配制好的液体（水、溴、溴试剂、盐酸）加入到反应装置内,恒温并等待Br^-生成;但由于橡皮塞孔径较大,在加入甲酸之前,易有液体从橡皮塞孔径挥发,使液体浓度发生改变,影响实验结果。     

苯的溴代反应实验再改进

从装置图中可以看出此实验存在以下不足：(1)所需仪器繁多且特殊,此装置看上去美观,笔者在装配时,很难找到两个小型分液漏斗,改常规大小的分液漏斗致使装置庞杂,操作不便,无法组织学生实验或探究性实验,据调查,许多学校甚至演示实验都不能正常开设。     

借助智能手机和分光镜鉴别混合物的焰色反应实验

用智能手机和手持式分光镜设计出可以快速准确记录混合物或单一金属离子光谱图的简易实验装置,并将所得光谱图导入ImageJ和Excel中得到较为精准的光谱波长图来验证装置的有效性。本实验装置亦可以设计为高中阶段化学兴趣实验,以便让学生初步了解现代化学仪器分析的一些基本原理。     

过氧化氢分解反应动力学实验的改进

过氧化氢分解反应实验,设备简单,直观性好,是个很好的教学实验。目前的教材中仍有采用。但是,该实验的量气装置多为立式。测量时需随时保持液面平齐。这给操作和读数带来不便。本文设计制做了一种水平量气装置。多次使用表明,操作方     

关于测量反应速率的实验改进

从实验装置、实验操作上对人教版新教材（选修4）中测量反应速率的方案进行了多种改进,并创新了其他测量反应速率的方案。     

辉光放电离子源质子转移反应质谱对水中苯的分析方法研究

报告了自行研制的质子转移反应质谱(Proton Transfer Reaction Mass Spectrometry, PTR-MS)装置结合动态气体提取技术直接测量水中苯浓度的新方法. N2连续地将水溶液中的苯提取出来, 用质子转移反应质谱测量其在液面顶空中的分压强P随时间的变化关系, 从而得到苯的亨利常数H 利用亨利定律就可以给出苯在水溶液中的浓度. 考察了苯在提取气体及水溶液中达到平衡需要的液面高度, 测量了28 ℃时苯的亨利常数. 以此为基础测试了水中苯的浓度, 测量结果与配制的溶液浓度相一致. PTR-MS结合动态气体提取技术测量水中苯的浓度, 检出限为1 μg/L. 方法可以拓展到水中其它挥发性有机物浓度的测量.     

离子分子反应装置的建立及应用

本文报导离子分子反应装置的建成并测量了O~++N_2反应的速率常数k.O~+离子由微波放电和电极电离产生,经快速流动,用四极质谱仪检测到.中性分子N_2经支管进入流动管,并与O~+离子反应,在温度为298 K 时,测得该反应速率常数为k=(2.50±0.52)×10~(-12)cm~3·molec~(-1)·s~(-1)(T=298 K)     

时间分辨热透镜法测量多原子分子的振动弛豫速率

用激光诱导产生的气体瞬态热透镜效应测量了分子中的振动能量弛豫速率.实验装置示意如图1.光栅选频的TEACO_2激光器用作激发光源,激光主脉宽100—200ns,每脉冲能量约     

挥发性及非挥发性以及含砷、锡、氟等有机化合物中碳氢微量测定法

有机碳氢微量分析法虽已有很多改进,但似尚缺一种既能用以测定挥发性又能测定非挥发性有机化合物中碳氢含量的装置.最近已有改进的测定固体及挥发性物质中碳氢的方法,但该装置专为测定含氟化合物中的碳氢含量而设计. 本文应用如图1的根据经验及综合前人方法制定的装置,分析若干挥发性及非挥发性液体与固体有机化合物以及元素有机化合物中碳氢含量,结果都令人满意(见表1).     

Application of thermal analysis in screening for chemical process hazards

The testing of substances and reaction mixtures for the prevention of process hazards poses special problems, which may be solved, to some extent, by commercial DTA and DSC equipment. The standard equipment specially designed for dynamic, isothermal and constant volume tests and the testing procedure is described. Finally, the principle of an evaluation method is briefly outlined.     

Interaction Between Fe and Cl2 in the Bed of Graphitized Carbon Black

A possible route to remove Fe catalyst from graphitized carbon black synthesized in Boudouard's reaction is employment of gaseous chlorine in role of carrier. This process was explored by means of DTA method using the equipment designed in the laboratory. Obtained results demonstrate the complexity of processes occurring in systems containing Fe, C and Cl₂. Reactions in the system are highly influenced by the geometry of reacting solids. Process of FeCl₃ intercalation between graphite layers was observed analyzing DTA curves. The amount of Fe in the raw product of Boudouard's reaction was determined during the process of chlorination. Obtained results indicate that Cl₂ stream does not remove all the Fe even at high temperatures and prolonged chlorinating time. This revised version was published online in August 2006 with corrections to the Cover Date.     

凯氏定氮装置的改进

针对传统凯氏定氮装置存在的问题,设计了一种新型的定氮装置,尤其对氮气球、通气开关、球型冷凝管进行了重新设计.实践证明,改进的凯氏定氮装置完全可以满足常量定氮分析.     

Bioreactor development with respect to process constraints imposed by bio-oxidation and waste remediation

Bioreactors serve a central role in biotechnological processes by providing the link between starting materials and final products. In most biological systems, there are complex series of reactions that must be optimized and coordinated in a very specific environment. Despite the complexity of biocatalytic processes, there is usually a rate-limiting step controlling the reaction, as well as a few secondary limitations. These limitations provide the basis for process design and bioprocess equipment specifications. The EIMCO Slurry Bioreactor has been designed to overcome these limitations encountered during the bio-oxidation of refractory gold ores and concentrates and hazardous waste bioremediation.     

A cell for high-precision constant-current coulometry with external generation of titrant

A cell has been designed for the high-precision coulometric titration, with externally generated titrant, of materials which otherwise undergo undesirable reactions at the working electrodes. With this cell potassium dichromate has been titrated, via its hydrolysis reaction, with hydroxyl ion generated at the cathode, cathodic reduction of the chromium(VI) being circumvented. In this cell 99.9% of the titrant required is generated in one chamber and transferred to another for reaction; the titration is then completed with titrant generated at a second, drip-type electrode working at much lower current. By means of commercially available Leeds and Northrup coulometric titration electrical equipment, titration of NBS 136b Potassium Dichromate gave a purity of 99.976%, standard deviation 0.005%, and of NBS 84d Potassium Acid Phthalate (done as a check) 99.991%, standard deviation 0.005%, both values being in excellent agreement with other work.     

1-Methylimidazole 3-N-oxide as a new promoter for the Morita-Baylis-Hillman reaction

The Morita-Baylis-Hillman reaction of aldehydes with α,β-unsaturated ketones can be affected by the Lewis bases. We have found that 1-methylimidazole 3-N-oxide promoted the Morita-Baylis-Hillman reaction of various activated aldehyde compounds in non-solvent system. This is a mild reaction condition and requires no special equipment to give the Morita-Baylis-Hillman adducts.     

Microreactors as the new way of intensification of heterogeneous processes

Microstructure reactors (microreactors) in recent decades became one of the most actively studied subjects of the reaction equipment aimed at intensification of chemical processes and increase in their safety. It is not surprising because due to miniature dimensions of microstructures which do not exceed 2 mm microreactors contribute to minimization of the material at their production as well as raw material and energy in the process of exploitation. Moreover, due to acceleration of heat and mass transfer the productivity of equipment with microreactors in a range of cases is significantly higher than classical batch reactors applied in industry. The brief overview of the modern development and achievements of microreactor technology is given in this article by an example of heterogeneous reaction systems which are different by their nature and occur in different types of microreactors: phase-transfer catalysis, biocatalysis, and synthesis of nanoparticles. A special attention in the article is paid to the aspects of intensification of the considered processes because exactly the possibility of intensification makes microreactor technology attractive for the industry.     

Development of a continuous homogeneous process for denitration by treatment with formaldehyde

Removal of nitric acid from high level liquid wastes (HLLW) of nuclear fuel reprocessing plants is warranted for simplifying the procedure for waste fixing. Chemical denitration aims to reduce the waste volume by destroying the acidity and subsequent concentration by adding suitable reductants. Reduction of nitric acid to gaseous products is an attractive way to accomplish denitration. Nitric acid reduction with formaldehyde proceeds with the formation of CO₂, NO₂, NO or N₂O depending on the reaction conditions and all the reaction products except water can be eliminated from the system in gaseous form. The HNO₃–HCHO reaction is governed by a complex mechanism of exhibiting relatively long induction period, depending upon the temperature, concentration of reactants and nitrous acid reaction intermediate. In the present work, a homogeneous denitration process with formaldehyde which offers safety and is governed by controlled kinetics was demonstrated on a laboratory scale. The induction period before commencement of the reaction was eliminated by maintaining the reaction mixture at a pre determined temperature of 98 °C. Based on the results accrued from lab scale experiments, the equipment for pilot plant scale operation was designed, the reaction efficiency for continuous denitration was determined and the investigation of nitric acid destruction was extended to full-scale plant capacity. The role of organics in the waste in foaming up of the reaction mixture was also studied using a synthetic waste solution.     

Computer-aided Modeling of the Time Dependences of the Current during Anisotropic Growth of Product Nuclei

A fast computer model, intended for the calculation of the overall reaction rate (current) of anisotropic or nonhomotetic growth of a new-phase nuclei on the basis of the Voronoi diagram, is designed. The model is used for studying the kinetics of a heterogeneous reaction in the conditions where hemispherical nuclei of the new phase acquire a semiellipsoid shape in the course of an anisotropic growth. The calculation of current transients (potentiostatic i vs. t dependences) is substantially complicated in the initial stage of reaction, where the size of growing nuclei exceeds the critical value by less than an order of magnitude. If semiellipsoid nuclei overlap, the overall reaction rate is not determined by variations in the overall area of the reaction surface, as opposed to the growth of hemispherical nuclei. The kinetics of a nonhomotetic nuclei growth may be described by models designed for an isotropic growth of hemispherical nuclei.     

液固吸附动态分析装置的研制及应用

本文从研究液固吸附动态分析装置如何稳压、稳流及如何检测原位信息等关键问题入手，设计和建立了一套可用于液固体系离子吸附研究的动态分析装置，并通过实验证明该液固吸附动态分析装置能快速、准确地给出离子在吸附剂上的吸、脱附动态信息，为液固体系的吸附研究提供了一种可靠的手段。