纳米铜薄膜氧化反应动力学规律研究

研究了140 ℃下纳米尺度Cu薄膜的氧化行为. 采用真空蒸发法以不同沉积速率制备一系列Cu薄膜, 利用原子力显微镜(AFM)观察其微观形貌, 选取形貌良好的Cu薄膜样品. 采用方块电阻和透射光谱两种方法为表征手段, 测量16～22 nm范围内不同厚度Cu薄膜在140 ℃下完全氧化所需要的时间, 得到了Cu薄膜氧化反应的动力学曲线, 并利用X射线衍射(XRD)分析了氧化产物的晶相结构和成分. 结果表明, 纳米尺度下Cu薄膜在140 ℃下氧化反应的动力学表征结果满足特殊的反对数生长规律, 反应产物为Cu₂O.     

硫脲氧化反应动力学研究进展

本文综述了硫脲氧化反应动力学的研究进展,根据氧化剂和氧化方式不同,将硫脲氧化体系分成含卤氧化体系和非卤氧化体系两大类,其中含卤氧化体系包括亚氯酸、碘酸、溴酸、卤素单质氧化硫脲的反应体系;非卤氧化体系包括双氧水、自由基、电化学和金属酸盐氧化硫脲的反应体系。总结了不同反应体系的动力学现象和反应机理研究状况,文中还介绍了在硫脲氧化反应动力学研究中光电磁及色谱方法的发展状况,提出硫脲氧化反应动力学机理研究突破可能途径。     

铜(Ⅱ)催化过氧化氢氧化5-Cl-PADAT褪色反应的动力学研究及其应用

在KH2PO4 NaOH介质中研究了铜(Ⅱ)催化H2O2氧化5 Cl PADAT的褪色反应,测定了反应动力学参数,并建立了测定痕量铜的新方法。本法检出限为6.25×10-11g mL,铜(Ⅱ)的质量浓度在0～2.24ng mL范围内与log(A0 A)呈良好的线性关系。该法已用于核桃、人发样中痕量铜的测定。     

醛类自氧化振荡反应动力学的研究

研究了醛类在乙酸和水混合溶剂中以Ｃｏ＾２＋和Ｂｒ＾－为催化剂的自氧化振荡反应。得知某些取代苯甲醛和脂肪醛在适当条件下能发生振荡，并研究了苯甲醛、正丁醛和乙醛的周期受动力学制约的影响，提出了相关的机理模型。依此模型以Ｇｅａｒ方法计算其振荡周期基本与实验结果相符。     

催化褪色反应动力学法测定痕量铜

作者发现铜(Ⅱ)对过氧化氢在硫酸介质中氧化甲基橙的褪色反应有催化作用,找到了影响催化褪色反应的最佳条件,建立了测定痕量铜(Ⅱ)的新方法。灵敏度为9.22×10~(-11)g/ml,测定范围0～2.0μgCu~(2+)/50ml。用于测定几种实物样品中的痕量铜,得到满意的结果。相对标准偏差0.2％～2.3％。     

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。     

邻苯二酚自氧化反应的动力学研究

利用单扫示波极谱法（并辅助光谱法）研究了邻苯三酚在ＰＨ７．２０－９．１０的ＴｒｉｓＨＣｌ缓冲体系中自氧化反应的动力学，结果表明，在过量溶解存在时，反应对邻苯三酚为一级，在一定ＰＨ范围内，准一级反应表观率常数ｋａｐｐ随ＰＨ值的增加而增加，说明Ｈ２ＰＹＲ比Ｈ３ＰＹＲ对溶解Ｏ２具有更高的反应活性，探讨了邻苯三酚生成半醌自由基和活性氧的反应的机理，用速度方程解释了实验现象，并为酶活力测定和药物抗氧活性研究     

肾上腺素氧化反应的研究——氧化反应动力学和机理以及自由基中间体

用紫外吸收光谱法结合计算机模拟研究了肾上腺素(Adjn)在Cu(Ⅱ)离子催化下,用H_2O_2氧化产生肾上腺素红(Adom)的反应动力学,考查了反应的速率随体系中肾上腺素的初始浓度,Cu(Ⅱ)离子浓度和H_2O_2浓度的变化情况。在流动法或添加自由基稳定剂的条件下,利用顺磁共振法检测丁肾上腺素自氧化,光氧化和Cu(Ⅱ)离子催化H_2O_2氧化产生的半醌自由基。考查了Cu(Ⅱ)离子催化下自由基的相对浓度随反应条件的变化情况。在反应动力学和顺磁共振实验的基础上所提出的可能的反应机理,半定量地解释此反应动力学实验结果和顺磁共振实验中的自由基行为。     

不同粒径氧化铜的制备及其氢还原动力学研究

以CuSO4.5H2O和NaOH为原料制备0.1mol·L-1CuSO4溶液和4mol·L-1NaOH溶液,采用沉淀法制备Cu(OH)2纳米粉末,然后分别在200℃,500℃,900℃温度下分解Cu(OH)2得到不同粒度的氧化铜粉体.在氢气中,以15℃.min-1升温速率,用SDT2960Simulta-neousDSC-TGA差热-热重分析仪测定TG-DTA曲线,并进行动力学计算.结果表明:氧化铜粉体的形貌近似为球形,粒径分别为50,150,400nm;DTA峰值温度分别为258.90℃,279.17℃,364.80℃,随粒径的增大而提高;表观活化能分别为173.39,461.54,534.80kJ·mol-1,随粒径的增大而增大;频率因子分别为1.15×1018,2.49×1045,2.54×1045,随粒径的增大而增大;反应级数分别为1.16,1.15,1.03,随粒径的增大而减少.     

Application of thermal analysis to study smelting reduction kinetics

A thermal analysis study on the reduction of iron oxide rich slags under different conditions is presented in this paper. The effects of important process variables such as time, temperature, lime-silica ratio, FeO level in slag etc. are discussed. It is shown that the mechanism of reduction by externally added graphite is different from that by a carbon saturated bath although the activation energy values are similar.     

Study on pyrolysis kinetics of walnut shell

Slow pyrolysis of walnut shell which is a cheap and abundantly available solid waste was carried out using thermogravimetric analysis. The effects of raw material heating rate on the pyrolysis properties and kinetic parameters were investigated. A two-step consecutive reaction model were used to simulate the pyrolysis process. The kinetic parameters were established by using the pattern search method. Comparison between experimental data and the model prediction indicated that the two-step consecutive reaction model can better describe the slow pyrolysis of walnut shell as the formation of an intermediate during the pyrolysis process was taken into account.     

Influence of solution composition and iron powder characteristics on reduction of 2,4,6-trinitrophenol

Kinetics of the 2,4,6-trinitrophenol reaction with iron powder was investigated voltammetrically. The process was found to be mainly governed both by the iron powder characteristics and by the solution composition. Degradation kinetics was generally represented by a pseudo-first-order rate law. Consecutively, the 2,4,6-trinitrophenol reduction reaction rates for three fractions of iron powder as well as the effect of individual ions presented in the reaction system were evaluated. A correlation between the reaction rate and both the grain size of iron particles and the state of their surface was found. The effect of the reaction system composition was investigated for two types of buffered medium: Britton-Robinson buffer (boric acid, orthophosphoric acid, and glacial acetic acid) and acetate buffer solution (sodium acetate and acetic acid).     

Electrochemical corrosion kinetics of cold spray copper composite coatings in a high potential region

In this paper, copper composite anticorrosion and antifouling coatings were prepared by a cold spray technique. Polarization experiments of the coatings were performed by rotating ring‐disk electrode technology at high potential. The electrochemical reaction mechanisms were proposed, and corresponding polarization kinetics models were built. Experimental results show that the copper and cuprous oxide formed corrosion microcells in the coatings, and the cuprous oxide did not alter the electrochemical reaction process of copper. In the high potential region (about 0.2–0.8 V), a CuCl film formed on the surface of the coatings was not damaged or broken down. The film played a role in corrosion protection. The currents in the high potential region increased relative to the limiting current 1. Because in the high potential region, was produced by the dissolution of the CuCl film and was oxidized to Cu²⁺. In addition to being oxidized to Cu²⁺, has the other two destinations, which were deposition as a CuCl film and diffusion to the solution bulk. The three processes were in parallel competition relations. In the limiting current 2 region, oxidation of was dominant. A rate‐controlling step of electrochemical dissolution of the coatings in the high potential region was the diffusion processes of and Cu²⁺. The electrochemical polarization kinetic models based on the reaction mechanisms established in this research accorded well to the experimental results. It demonstrated the rationality of polarization kinetics models and reaction mechanisms.     

甲基磺酸铜制备的绿色工艺与动力学

甲基磺酸(ＭＳＡ)及其盐类能改善镀层性能,并可实现无氰电镀[1-4],本文采用空气氧化法直接由紫Ｃｕ与ＭＳＡ水溶液反应生产(ＣＨ3ＳＯ3)2Ｃｕ·5Ｈ2Ｏ,达到了工艺绿色化的要求。1　实验部分1 1　试剂与仪器70%ＭＳＡ(宝鸡科隆化工有限公司);99 9%紫铜片(沈阳冶炼厂);氧气(宝鸡有色金属加工厂氧气分厂);其余试剂均为分析纯试剂。ＡＡ7003Ａ原子吸收光谱仪(北京市东西电子技术研究所);ＰＩＣ-8型离子色谱仪(青岛普仁仪器有限公司);超级恒温槽。1 2　实验将500ｍｌ三口磨口烧瓶装于超级恒温槽中,装温度计、鼓气管,第三只磨口连续接装3支磨…     

Effect of chloride ions on the kinetics of nitrobenzene reduction by powdered iron

The effect of different chloride ions concentrations on the reactivity of iron particles was studied using chronopotentiometry. It was found that the increase of Cl⁻ ions concentration accelerated anodic dissolution of iron, thus enhancing its surface reactivity. This fact was confirmed also by the rate of nitrobenzene reduction by iron particles. The reactivity of powder particles of various sizes, hence of different specific surface, was investigated in chloride-free and chloride-containing acetate buffer electrolytes. Experimental results indicated that the rate of nitrobenzene reduction in the presence of chloride ions in the reaction system is faster in comparison with the rate in chloride-free medium for each studied grain fraction of particulate material.     

Study on kinetics of the pyrolysis process of aluminum sulfate

Abstract

Using high aluminum gangue as a raw material, aluminum sulfate 18 hydrate was made by the sulfuric acid leaching method under certain conditions. The product was characterized using X-ray diffraction (XRD) analysis of the phases, x-ray-fluorescence (XRF) analysis of the aluminum and sulfur content and thermogravimetric analysis of the crystallized water [Al₂(SO₄)₃·18H₂O]. Change characteristics of the crystal form and morphology during pyrolysis of octadecahydrate aluminum sulfate were studied by thermogravimetric Analysis (TGA), differential scanning calorimetry (DSC), differential thermogravimetry (DTG), XRD and scanning electron microscope (SEM). The theoretical basis for the preparation of metallurgical alumina from octadecahydrate aluminum sulfate was provided. According to the characteristics of the crystal structure change, the pyrolysis process of octadecahydrate aluminum sulfate can be separated into three stages. The first stage (dehydration stage 87–250?°C) had a weight loss rate of 40.5% and a loss of 15 water molecules; the weight loss rate of the second stage (dehydration stage 280–414?°C) was 8.1% with three water molecules lost; the weight loss rate of the third stage (decomposition stage 770–900?°C) was 36.1%, where three SO₃ molecules were lost. The pyrolysis products were mainly Al₂O₃. The activation energies of the three reaction stages were calculated using the Coats-Redfern method as 90.02?kJ/mol, 205.74?kJ/mol and 284.40?kJ/mol, respectively.     

Wittig-Horner反应的动力学研究

Ｗｉｔｔｉｇ Ｈｏｒｎｅｒ反应是Ｗｉｔｔｉｇ反应的一种改进 ,二者可以互相补充 ,但Ｗｉｔｔｉｇ Ｈｏｒｎｅｒ反应还具有某些独特的优点[1] 。Ｗｉｔｔｉｇ Ｈｏｒｎｅｒ反应用于合成的研究有较多的报道 ,但对于该反应的理论研究却不多见[2 ] 。因此 ,我们合成了α 萘甲基磷酸二丁酯 ,并进行了它同一系列取代苯甲醛反应的动力学研究。在磷酸酯及醇钠恒定过量的条件下 ,测定了几种取代苯甲醛反应的假一级速率常数值。但实际上反应属于三级 ,对磷酸酯、乙醇钠和苯甲醛各为一级。因为当改变各反应组份的浓度时 ,速率发生改变。一般Ｗｉｔｔ…