F1树脂吸附和解吸铼的性能研究

研究了新型功能性阴离子交换树脂－Ｆ１树脂吸附和解吸铼的性能。通过静态试验,考察了铼的介质酸度、温度、溶液铼浓度及时间对树脂吸附和吸铼的影响;在动态试验中,考察了溶液铼浓度,溶液流速和解吸剂流速的影响,对解吸剂和掩蔽剂及其浓度的选择做了较详细的探索,并研究了树脂再生和循环使用情况,试验结果较理想,表明了Ｆ１树脂是一种有很有发展前途的新功能离子交换树脂。     

Single‐Pot Ethane Carboxylation Catalyzed by New Oxorhenium(V) Complexes with N,O Ligands

The oxorhenium(V) chelates [ReOCl(N,O‐L)(PPh₃)] [N,O‐L=(OCH₂CH₂)N(CH₂CH₂OH)(CH₂COO) ( 2 ), (OCH₂CH₂)N(CH₂COO)(CH₂COOCH₃) ( 3 )] and [ReOCl₂(N,O‐L)(PPh₃)] [N,O‐L=C₅H₄N(COO‐2) ( 4 ) C₅H₃N(COOCH₃‐2)(COO‐6) ( 5 )] have been prepared by reaction of [ReOCl₃(PPh₃)₂] ( 1 ), in refluxing methanol, with N,N‐bis(2‐hydroxyethyl)glycine [bicine; N(CH₂CH₂OH)₂(CH₂COOH)], N‐(2‐hydroxyethyl)iminodiacetic acid [N(CH₂CH₂OH)(CH₂COOH)₂], picolinic acid [NC₅H₄(COOH‐2)] or 2,6‐pyridinedicarboxylic acid [NC₅H₃(COOH‐2,6)₂], respectively, with ligand esterification in the cases of 3 and 5 . All these complexes have been characterized by IR and multinuclear NMR spectroscopy, FAB⁺‐MS, elemental and X‐ray diffraction structural analyses. They act as catalysts, in a single‐pot process, for the carboxylation of ethane by CO, in the presence of potassium peroxodisulfate K₂S₂O₈, in trifluoroacetic acid (TFA), to give propionic and acetic acids, in a remarkable yield (up to ca. 30%) and under relatively mild conditions, with some advantages over the industrial processes. The picolinate complex 4 provides the most active catalyst and the carboxylation also occurs, although much less efficiently, by the TFA solvent in the absence of CO. The selectivity can be controlled by the ethane and CO pressures, propionic acid being the dominant product for pressures about ca. 7 and 4 atm, respectively (catalyst 4 ), whereas lower pressures lead mainly to acetic acid in lower yields. These reactions constitute an unprecedented use of Re complexes as catalysts in alkane functionalization.     

稀散元素铼的分析进展

铼属于贵重稀散金属元素,铼的分析方法发展较快。本文综述了近年来国内外铼的分析进展,包括了矿样的分解、铼的分离富集以及铼的测定。     

从砂岩型铀矿中综合回收铼研究进展

铼是地壳中极其稀散的元素之一,在航空航天、石油催化等领域有着极为重要的作用。主要归纳总结了国内外铼的资源状况、从砂岩型铀矿中分离富集铼的材料、提取铼的有关工艺(离子交换法和溶剂萃取法)研究进展,并对综合回收铼的发展方向进行了展望。     

铼（Re）在单晶高温合金中的作用

综述了铼（Ｒｅ）对单晶高温合金显微组织，力学性能，不稳定相及单晶缺陷等的影响，并拽出了今后的研究方向。     

Photoemission studies of rhenium disulfide oxidation: Altered core-level structure and reactivity of defect sites

X-ray photoemission was used to investigate the initial stages of rhenium disulfide oxidation and the altered reactivity and core-level electronic structure of defect sites produced by argon ion sputtering of single crystal and polycrystalline ReS₂-basal plane surfaces. Oxidation of polycrystalline-ReS₂ with O₂ at 100–300 ° C produced a mixture of surface oxides containing rhenium in the + 4 and + 7 oxidation states. Oxidation was facilitated by the presence of low coordination defect sites and was reversible upon resulfidization with H₂S/H₂ at 300 °C.     

A novel method of examining carbonaceous deposits on spent catalyst surfaces

Xenon ion-bombardment used in conjunction with Auger electron spectroscopy was able to discriminate two types of carbonaceous materials accumulated on the surfaces of iron oxide and rhenium/iron-oxide catalysts spent for CO hydrogenation at 250°C and 2.1 MPa. One of the carbonaceous materials was easily eliminated from the surfaces by ion bombardment or by heat-treatment in vacuo at 150°C. On iron oxide only this “soft” carbonaceous material was present. On rhenium/iron oxide, bombardment-resistant “hard” carbonaceous material was also found. The presence of this hard carbonaceous material had little effect on the level of CO hydrogenation activity or the deactivation behavior of this catalytic system.     

SEPARATION OF Re AND Mo BY ADSORPTION OF ACTIVE CARBON

Separation of Re and Mo by adsorption of active carbon has been studied. The results show that Re and Mo can be separated effectively by adjusting the pH value. As pH>8.2. the coefficient of separation S_(Rc)/Mo>3.042. The adsorption isotherm for Re conforms to the Freundlich formula.     

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47．6h。     

铼/铱发动机喷管研究最新进展

Re/Ir发动机是美国研制成功的应用于空间飞行器的第三代高性能发动机.作者对Re/Ir发动机的核心部件-Re/Ir喷管研究的国内外进展进行了简要的评述,内容包括:Re和Ir的性能;Re和Ir的CVD制备;Re/Ir喷管的制备;Re/Ir喷管的连接以及发动机工作寿命等.