铬黑T-溴酸钠催化动力学分光光度法测定铼

基于在硫酸介质中,铼催化溴酸钠氧化铬黑T的褪色反应,建立了测定铼的光度分析新方法。确定了催化体系的动力学条件,计算得出催化反应的表观活化能Ea=39.12KJ/mol,反应速率常数为K=1.248×10-3/s。在选定的试验优条件下,铼的浓度在0~10.02mg/L范围内与相对吸光度呈良好的线性关系,检出限为2.7675mg/L。方法所用仪器简单,操作简便。     

铼基电镀铂工艺研究

以热表面电离质谱计用铼带为基底材料,对比了多种电镀铂体系。结果表明,磷酸盐体系电镀效果最好。分析了各种工艺参数对镀层质量的影响,确定了铼基电镀铂的最佳工艺条件为:H2PtCl6(以Pt计)0.2g/L,(NH4)2HPO440g/L,Na2HPO4140g/L,十二烷基磺酸钠0.01g/L,温度85°C,阴极电流密度4A/dm2,电镀时间20min。适当的真空热处理有助于获得光亮平整、结合力良好的镀层。X射线能谱分析表明,铂镀层厚度可达微米级。     

铼的氧化动力学研究

采用热重分析(TGA)技术分别研究了粉末冶金(PM)Re和化学气相沉积(CVD)Re在空气中的氧化规律。PMRe在1000℃以上的氧化遵循与格纳的厚膜氧化规律，即氧化速率遵从抛物线定律；而在较低的温度下，CVDRe的氧化失重与时间呈直线关系。PMRe和CVDRe的氧化失重与温度的关系均符合Arrhenius公式。     

Technological and economical aspects of the metathesis of unsaturated esters

The metathesis of alkenes is a well-established reaction that is applied in various commercial processes. The meta-thesis of functionalized olefins has not yet been commercialized despite its considerable potential. The conversion of oleochemical feedstocks into specialty chemicals appears especially attractive. In this paper, a process scheme is proposed for the production of 1,18-dimethyl octadecanedioate from pure methyl oleate by metathesis. The chemical and technological bottlenecks are explored, and a rough economic evaluation of this route is given. From these considerations, it is concluded that such a process for the metathesis of functionalized alkenes could be viable only if certain conditions are met. Rapid catalyst deactivation is identified as one of the main obstacles. Feedstock purity, efficient recycling of unreacted feed and multiple catalyst regeneration are crucial for economic feasibility. Rhenium-based catalysts are to be preferred over molybdenum ones because their activation is easier and regenerability is superior. Finally, the direction for future technological and catalysis research is given based upon the results of this work.     

CVD法制备的Ir/Re涂层复合材料界面扩散研究

采用化学气相沉积(CVD)技术制备了Ir/Re 涂层复合材料,并在高温高真空条件下对复合材料样品进行扩散热处理。应用电子扫描波谱法探针研究了Ir/Re复合材料界面Re元素在Ir涂层中的扩散规律。应用半无限大扩散模型进行处理,得到了1400-2000℃温度范围的实验扩散系数,扩散系数与温度之间符合Arrhenius方程。根据实验结果推算,Ir/Re复合材料在2200℃时的工作寿命为47.6小时。     

The Effect of Sintering on the Properties of Ultrafine

研究了一种化学气相沉积(CVD)制备超细铼粉的新方法,即以NH4ReO7为原料,通过将其分解为Re2O7后气相输运至还原区,经氢气还原生成超细铼粉。对不同还原温度下制备的超细铼粉样品,采用XRD、SEM、激光粒度分析进行表征,实验揭示了烧结作用对晶粒尺寸、形貌、表面状态及粒度等粉末性能的影响规律。结果表明,随还原温度升高,烧结作用增强,制备的超细铼粉晶粒尺寸增大,具有更好的球形度,表面趋于光洁,平均粒径增大。     

Effect of alumina-deficiency and promotion with platinum and rhenium on the catalytic and diffusional behaviour of mordenite catalysts

The hydroconversion of n-heptane on catalysts containing platinum hydrogen-mordenite, platinum/alumina-deficient hydrogen mordenite and platinum-rhenium/alumina-deficient hydrogen mordenite was carried out in a continuous high-pressure plug-flow reactor system and product analysis was carried out by gas chromatography (GC). The effectiveness factor for each catalyst was calculated by iteration on estimated rate constant at various reaction temperatures and the effect of diffusion on the catalytic behaviour was correlated. Catalysts exhibiting larger values of effectiveness factor were found to enhance production of 2,3-dimethylpentane on account of 3-methylhexane, whereas the reverse is true with respect to catalysts exhibiting lower values of effectiveness factor.     

The high-temperature effective work function of chemically vapor deposited rhenium on a polycrystalline molybdenum substrate

The work function of chemically vapor deposited rhenium, with a (0001) preferred orientation, on a molybdenum substrate was determined using the thermionic emission method. Data were collected as a function of time and temperature on temperature ramps from 1800 to 2600 K in 100-K increments. The effect of pressure on effective work function was demonstrated by introducing oxygen, nitrogen, and carbon dioxide through a precision leak valve into the vacuum emission vehicle. The effect of introducing various gasses was negligible. Also, no significant time or temperature dependence was observed. The sample yielded the maximum average effective work function, 5.08 eV, at 2100 K. The overall average effective work function was determined to be 5.02 eV.     

铜冶炼过程中硫化砷渣综合利用技术

针对铜冶炼过程中产出的硫化砷渣的处理工艺进行了评述,并对新研究开发的酸性加压氧化浸出工艺进行了详细介绍.硫化砷渣经酸性加压氧化浸出后,铜、砷及铼的浸出率均达到95%以上,硫则以单质形态进入浸出渣中.浸出液经二氧化硫还原冷却脱砷进而可生产优质As2O3,脱砷后液经溶剂萃取提取铼用于生产高铼酸铵,萃余液再经蒸发结晶可以生产硫酸铜.由此,硫化砷渣中的铜、砷、铼、硫都得到综合回收.