Selective Hydrogenation of Amides using Ruthenium/ Molybdenum Catalysts

Recyclable, heterogeneous bimetallic ruthenium/molybdenum catalysts, formed in situ from triruthenium dodecacarbonyl [Ru₃(CO)₁₂] and molybdenum hexacarbonyl [Mo(CO)₆], are effective for the selective liquid phase hydrogenation of cyclohexylcarboxamide (CyCONH₂) to cyclohexanemethylamine (CyCH₂NH₂), with no secondary or tertiary amine by‐product formation. Variation of Mo:Ru composition reveals both synergistic and poisoning effects, with the optimum combination of conversion and selectivity at ca. 0.5, and total inhibition of catalysis evident at ≥1. Good amide conversions are noted within the reaction condition regimes 20–100 bar hydrogen and 145–160 °C. The order of reactivity of these catalysts towards reduction of different amide functional groups is primary>tertiary≫secondary. In situ HP‐FT‐IR spectroscopy confirms that catalyst genesis occurs during an induction period associated with decomposition of the organometallic precursors. Ex situ characterisation, using XRD, XPS and EDX‐STEM, for active Mo:Ru compositions, has provided evidence for intimately mixed ca. 2.5–4 nm particles that contain metallic ruthenium, and molybdenum (in several oxidation states, including zero).     

溶胶-凝胶法制备MoP/SiO_2催化剂及其加氢脱硫催化活性的研究

以正硅酸乙酯为硅源,以钼酸铵和磷酸二氢铵为钼源和磷源,采用溶胶-凝胶法,经干燥、焙烧处理后,程序升温还原制备得到二氧化硅负载磷化钼(MOP)催化剂,并以二苯并噻吩为模型化合物,对催化剂的加氢脱硫活性进行初步评价,考察了负载量、反应压力、反应温度等因素对催化活性的影响.结果表明,溶胶-凝胶法制备负载催化剂最佳磷化钼负载量为20%(质量分数);升高反应压力和温度均有利于提高二苯并噻吩的转化率,但降低了产物中联苯的含量.     

河南某钼矿尾矿砂综合利用研究

河南省某矿业有限公司钼矿生产线每日产生尾矿砂近千吨,作者经过对该矿砂样进行选矿试验研究,其产品中100～600μm粒级精砂可达到中华人民共和国《平板玻璃用硅质原料》标准Ⅰ类二级品要求;可提供玻璃、玻纤工业作为主要原料及陶瓷工业辅助原料;45～600μm粒级精砂可提供水泥工业作为辅助原料。     

钛合金涂覆二硫化钼膜工艺

给出了钛合金涂覆MoS2膜的工艺流程,主要包括:有机溶剂除油,碱洗,脉冲阳极氧化,涂覆掺有MoS2粉末的环氧树脂和固化.介绍了各流程的工艺配方,测试了涂覆MoS2膜前后钛合金的动摩擦因数与时间的关系.试验表明,该工艺处理的钛合金工件具有良好的润滑性、耐磨性和耐蚀性.     

化学镀Ni-P-MoS_2复合镀层的制备与表征

在铁片上,采用化学镀的方法制备了Ni-P-MoS2复合镀层.讨论了表面活性剂PEG1500质量浓度及镀液pH对镀层形貌与沉积速率的影响.观察了镀层的表面及断面形貌,分析了镀层断面的元素分布,表征了镀层的成分,结构及相组成.结果表明,所得到的化学镀Ni-P-MoS2复合镀层为非晶态结构,颗粒分散均匀,尺寸约为0.2～3.0 μm.     

Large-area vapor-phase growth and characterization of MoS(2) atomic layers on a SiO(2) substrate

Atomic-layered MoS(2) is synthesized directly on SiO(2) substrates by a scalable chemical vapor deposition method. The large-scale synthesis of an atomic-layered semiconductor directly on a dielectric layer paves the way for many facile device fabrication possibilities, expanding the important family of useful mono- or few-layer materials that possess exceptional properties, such as graphene and hexagonal boron nitride (h-BN).     

测定钨铁中钼的简便方法

建立了不经分离用电感耦合等离子体发射光谱（ICP—AES）直接测定钨铁中钼的方法。样品经过硝酸-盐酸-氢氟酸混合酸溶解后于优化选定的仪器条件下在202．031nm处直接测定,结果与化学法有很好的吻合,相对标准偏差（RSD）小于0．06％,使用本方法的测定结果令人满意,相对于复杂的化学分析方法,该法操作简便、分析快速、结果准确可靠。     

某钨锡矿枱浮中尾矿钼铜锌浮选试验研究

某钨锡矿枱浮尾矿中钼、铜、锌金属品位较高,通过进行钼、铜、锌矿物综合回收的浮选流程试验研究,确定“钼铜混浮-分离,锌硫混浮-分离”的部分混合浮选原则流程;经浮选条件试验、综合条件试验和试验室闭路试验获得理想选别指标。     

Relationship between solids flux and froth features in batch flotation of sulphide ore

The froth features in the batch flotation of a sulphide ore were investigated by using the digital image parameters of the froth, the small number emphasis（Nsne）, the average grey level（Dagl） and the instability number （Nins）, under different conditions of impeller speeds and aeration rates. It is found that the value of Nsne is strongly dependent on the average bubble size of the froth and Dagl on the volume fraction of solid in the froth, and the froth features during the batch flotation are influenced by impeller speed and aeration rate. A kinetic model of the concen- trate solid flux was developed which relates the flotation process to the image parameters, Nsne and Dagl of the froth and predictions are well consistent with the experimental data.     

Changes in metal–sulfur bond energy in promoted and unpromoted molybdenum catalysts

Insight into the changes in the metal–sulfur bond energy in unpromoted and promoted (Co, Ni, or Fe) MoS₂ catalysts is obtained by temperature‐programmed reduction (TPR) studies of in situ sulfided catalysts. The experiments reveal a significant decrease in the metal–sulfur bond energy for the more active Co–Mo–S and Ni–Mo–S structures as compared to MoS₂. A similar decrease is not observed for the less active Fe–Mo–S structure. The sulfur coordination is directly measured by in situ EXAFS and the results support that one of the roles of the promoter atoms is to facilitate vacancy formation. The findings are in accord with recent density functional theory calculations. This revised version was published online in July 2006 with corrections to the Cover Date.