超细镍基负载型催化剂成型工艺条件研究

以正硅酸乙酯、钛酸丁酯、硝酸镍为主要原料,采用溶胶-凝胶法(Sol-gel)实验室放大制备10 kg工业中试用催化剂粉料，加胶粘剂A进行挤条成型。催化剂前躯体的物化性能用BET、XRD、TG-DTA、TEM及强度测试仪进行表征，用固定床连续流动微反装置，考察催化剂苯加氢生成环己烷的催化性能。研究结果表明，催化剂的强度随胶粘剂的含量增大而增大，当胶粘剂含量达到13％时，NiO/SiO₂-TiO₂体系产生了新的晶相。胶粘剂的含量对催化剂的催化性能影响很小，该催化剂应用于苯加氢制环己烷实验中，苯转化率均为100％，环己烷的选择性均达到99.0％以上。     

喹喔啉类衍生物与甲基噻吩共聚物的合成及性质

在二价镍配合物催化下,2,5-二溴-3-甲基噻吩格氏试剂与5,8-二溴-萘基喹喔啉和5,8-二溴-菲基喹喔啉共聚,得到相应的喹喔啉类共轭共聚物,收率分别为65%和68%。通过FT IR、1H-NM R对聚合物及中间体的结构进行了表征。聚合物的循环伏安图中,分别在0.66 V(Epa)/0.37 V(Epc)(Copo ly-m er I),0.78 V(Epa)/-0.06V(Epc)和1.26(Epa)/0.46(Epc)(Copo lym erⅡ)处观察到氧化还原峰,表明该类聚合物有电化学活性。在紫外-可见光谱中,分别在263 nm,323 nm处(Copo lym erⅠ)和299 nm,402 nm处(Copo lym erⅡ)出现吸收峰。所得聚合物分别在504 nm和513 nm处出现荧光最大发射峰。     

Ni–Pt/H-Y Zeolite Catalysts for Hydroisomerization of n-Hexane and n-Heptane

Ni–Pt/H-Y zeolite catalysts with different Ni contents were prepared and applied to the hydroisomerization of n-hexane and n-heptane in the temperature range 225-375 °C. ESCA studies show the complete reduction of Ni species up to 0.3 wt% Ni addition over 0.1 wt% Pt/H-Y and further addition leads to the occurrence of unreduced nickel species as NiAl₂O₄. A TEM study shows the formation of bimetallic (Ni–Pt) particles of nanoscale size and the average particle size is found to increase with increasing Ni loading. Acidity measurements by NH₃-TPD and pyridine-adsorbed FTIR spectroscopy show the increasing occupation of acid sites by the added nickel when increasing the nickel loading. The catalytic activity of Ni–Pt/H-Y zeolite and Pt/H-Y catalysts was compared and it was found that addition of Ni up to 0.3 wt% increases the n-hexane and n-heptane conversion, multibranched isomer selectivity and sustainability of the catalysts due to better metal-acid synergism, complete reduction of Ni species and the formation of catalytically active Ni–Pt bimetallic particles. Further Ni addition leads to a decrease in conversion and multibranched isomer selectivity and an increase in the cracked products, which may be due to the presence of unreduced Ni species and pore blockage by larger-sized bimetallic particles formed.     

Ni纳米粉体及其合金的制备与研究进展

纳米Ni及其合金是一类重要的磁性材料和抗磨损材料,被广泛用于催化剂、电池、涂层、通讯以及电子等诸多领域。本文就纳米Ni及其合金的制备进行综述,描述和分析了目前各种主要制备方法的特征及各自的优缺点,并对其应用前景作出了进一步的展望。     

钛基体化学镀镍及其耐蚀性能

采用化学镀在钛基体上制备Ni-P合金镀层.研究了活化时间、镀液pH值、热处理温度及时间对镀层的影响.用动电位极化曲线法比较镀层的耐均匀腐蚀性能,并用X-射线衍射仪和扫描电子显微镜分别研究镀层结构和表面形貌.结果表明,以HF为主剂的活化液,时间60 s,pH值4.8～5.2的活化工艺以及250 ℃、保温2 h的热处理为最佳工艺.镀层具有较高的耐蚀性能,属于非晶和微晶组成的混晶结构.借助于正交试验,确定了最佳工艺.     

Liquid-phase stereoselective thymol hydrogenation over supported nickel catalysts

The stereoselective hydrogenation of thymol was studied in liquid phase over several nickel catalysts, modified by coimpregnation of inorganic compounds containing chlorine. The total activity of all catalysts studied was decreased and was on the same order of magnitude, indicating that chlorine even after reduction remains on the surface and is responsible for the poisoning effects. Such blocking of accessible sites results in similar reaction rates for the catalysts studied. Selectivity and stereoselectivity to menthols and menthones changed significantly. The modifiers could influence the rate of keto-enol transformations, which is thought to be the key selectivity and stereoselectivity governing step.     

硫酸镍催化合成紫罗兰酮

用硫酸镍催化假性紫罗兰酮的环化反应，得到了较高产率的紫罗兰酮。探索了催化剂用量、反应温度、反应时间、溶剂用量和溶剂的种类等因素对该环化反应的影响。最佳合成条件如下：5．6mL（79．6％）假性紫罗兰酮，催化剂用量为假性紫罗兰酮的3％（摩尔百分率），甲苯（溶剂）用量为8mL，环化反应温度为40～50℃，反应时间为2．5h，在此合成条件下所得紫罗兰酮的产率为67．4％。选择极性较大的物质（如三氯甲烷）作溶剂有利于该环化反应的进行。     

化学镀镍-铜-磷三元合金工艺的研究

为提高化学镀镍－磷合金镀层的性能及获得多种性能的合金镀层以拓宽其应用范围。在化学镀镍－磷合金液中加入硫酸铜制得镍－铜－磷三元合金。研究了镀液中硫酸镍、次磷酸钠、柠檬酸钠、硫酸铜、稳定剂、光亮剂的含量以及pH值和温度等因素对合金镀层的外观、沉积速度及铜含量的影响。通过5％氯化钠溶液和10％硫酸溶液浸泡试验比较了所得镍－铜－磷合金镀层与镍－磷合金镀层以及前人制得的镍－磷合金镀层的耐蚀性，同时比较了上述镀层的其它性能。结果表明，所得镍－铜－磷合金镀层的耐蚀性、外观、结合力、孔隙率、沉积速度、硬度和耐磨性等性能优于镍－磷合金及前人制得的镍－铜－磷合金镀层。     

Self-assembly and crystallization behavior of a double-crystalline polyethylene-block-poly(ethylene oxide) diblock copolymer

The self-assembly and crystallization behavior of a well-defined low molecular weight polyethylene-block-poly(ethylene oxide) (PE-b-PEO) diblock copolymer was studied. The number-average degrees of polymerization for the PE and PEO blocks were 29 and 20, respectively. The molecular weight distribution was 1.04 as determined by size-exclusion chromatography. The PE-b-PEO sample exhibited two melting points at 28.7 and 97.4 °C for the PEO and the PE crystals, respectively. The crystallization of the PE blocks was unconfined, while the crystallization of the PEO blocks was confined between pre-existing PE crystalline lamellae, as demonstrated by simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) studies. In the fully crystalline state, both PE and PEO blocks formed extended-chain crystals with PE chains tilted ∼22° from the lamellar normal and PEO chains parallel to the lamellar normal, as evidenced by two-dimensional WAXD study of shear-oriented samples. Regardless of hydrogen bonding among hydroxyl chain ends in the PEO blocks, interdigitated, single-crystalline layer morphology was observed for both PE and PEO crystals. The partial crystalline morphology, where the PE crystallizes and the PEO is amorphous, had the same overall d-spacing as the fully crystalline morphology. A double-amorphous PEO layer sandwiched between neighboring PE crystalline layers was deduced based on a chain conformation study using Fourier transform infrared. The confined crystallization kinetics for PEO blocks was investigated by differential scanning calorimetry, which could be explained by a heterogeneous nucleation mechanism. The slower crystallization rate in the PEO-block than the same molecular weight homopolymer was attributed to the effects of nanoconfinement and PEO chains tethered to the PE crystals.     

改性钼镍粉在催化缩酮反应中的应用

用改性钼镍粉作催化剂。催化环己酮与乙二醇进行缩合反应。合成了环己酮乙二醇缩酮产物。通过实验选择出了改性钼镍粉催化缩铜反应的最佳条件:n(环己酮)∶n(乙二醇)=1∶2。环己烷作带水剂,其用量为15mL,催化剂用量为环己酮质量的7%,回流反应时间4h。环己酮乙二醇缩酮的总收率为90.5%。