Solvothermal Synthesis of Molybdenum Disulfide Hollow Spheres Modified by Cyanex 301 in Water–Ethanol Medium

Hollow spherical molybdenum disulfide has been successfully synthesized via a solvothermal method using Cyanex 301 as sulfur source and modification agent. The hollow spheres are characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction and Energy-Dispersive X-ray analysis. The influences of reaction conditions are also discussed while a mechanism is proposed to explain the formation of the peculiar morphology.     

The use of sulfide cluster-derived catalysts to understand the promotional effect in hydrotreatment catalysis

Sulfide cluster-derived ensembles are promising models of the active sites in commercial hydrotreatment catalysts. A series of sulfide clusters were adsorbed intact onto high-surface-area γ-alumina, magnesium oxide and activated carbon supports, then pretreated to produce highly dispersed catalytic ensembles with sizes similar to those of their precursor clusters. The activities of the bimetallic cluster-derived catalysts were significantly higher than those of the monometallic catalysts. We took this as evidence that direct interactions between molybdenum and the promoter element cause the promotional effect observed in commercial hydrotreatment catalysts. The hydrodesulfurization and hydrodenitrogenation activities correlated with the extent of molybdenum reduction. Our results suggested that the active sites in promoted hydrotreatment catalysts are centered on molecular-scale ensembles containing molybdenum, sulfur and the promoter element.     

还原温度对超细K－Co－Mo催化剂合成低碳醇性能的影响

 用溶胶－凝胶法合成了K－Co－Mo催化剂．样品经不同温度还原后，用于低碳醇的合成．XRD和HRTEM结果表明，样品是超细粒子，粒子尺寸为2～5nm．考察了催化剂的还原温度和反应条件对催化剂性能的影响．实验结果表明，还原温度对催化剂的活性有较大的影响，最佳还原温度为500℃．最佳反应温度范围为310～330℃．升高压力和空速可以提高醇的收率和选择性．在空速14400h－1，压力6．0MPa和温度310℃的条件下，醇的选择性为55．8％，收率为520．0g／（kg·h），MeOH／C2＋OH为0．27．催化剂稳定性良好，在200h的寿命实验中，活性基本不变．与文献中催化剂相比，超细K－Co－Mo催化剂对合成醇具有较高的活性和选择性，尤其是对C2＋OH的合成明显高于其他合成醇催化剂体系．     

罗丹明B-Mo(V)-SCN~--PVA体系荧光熄灭法测痕量钼

在聚乙烯醇存在下,用罗丹明B-Mo(V)-SCN~-荧光熄灭法测Mo,能消除过量的SCN-对罗丹明B的熄灭作用。加入聚乙烯醇后体系的荧光熄灭倍数比未加入时大14倍。此法灵敏度高、稳定性好、操作简便,检测下限0.12ng/ml Mo.可用于测水和头发中的钼。     

二氧化碳与丙烯直接合成甲基丙烯酸用CuPMo／TiO2催化剂的研究

 用溶胶－凝胶法以磷钼酸（MPA）的铜盐溶液水解钛酸四丁酯制备了CuPMo／TiO2催化剂，并用ICP，XRD，TG－DTA，IR，TPD－MS和微反技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化性能．结果表明：杂多钼酸盐与TiO2表面通过O2－桥发生键联．在623K下，杂多阴离子仍保持其原有的Keggin结构；CO2在Lewis酸位Cu（Ⅱ）和Lewis碱位Cu－O－Mo桥氧的协同作用下形成卧式吸附态Cu（Ⅱ）←O－（CO）←（O－－Cu）；丙烯以分子吸附态在催化剂上吸附；在空速1500h－1，压力1MPa和温度563K的反应条件下，丙烯的转化率为4．2％，甲基丙烯酸的选择性为96％．     

Studies of a new series of ion-pair complexes [Mo(dtc)_4][Ln(dtc)_4] (Ln=La-Er,exp.Pm)

A new series of ion-pair complexes [Mo(dtc)4][Ln(dtc)4] (Ln=La-Er, exp. Pm) were synthesized from MoCl5, LnCl3 and Nadtc in anhydrous methanol. The crystal structures of the four complexes, [Mo(dtc)4][Ln(dtc)4] (Ln=Nd, Sm, Ho and Er) have been determined by X-ray diffraction. Spectroscopic properties of all these complexes are also discussed here.     

Hydrothermal synthesis of potassium molybdenum oxide bronzes: structure-inheriting solid-state route to blue bronze and dissolution/deposition route to red bronze

The hydrothermal syntheses of the alkali metal molybdenum bronzes from starting solids (H_xMoO₃) with structural affinities to the desired products were investigated. Single-phase potassium blue and red bronzes were prepared by the hydrothermal treatments at around 430 K, and characterized by powder X-ray diffraction, IR spectroscopy, and SEM. The formation processes of these two bronzes during the hydrothermal treatments were found to differ. The blue bronze was formed by a structure-inheriting solid-state route from H_xMoO₃ with x<0.3, whereas the red bronze was formed for x>0.3 through a solution dissolution/deposition route via the formation of MoO₃+MoO₂.     

Chloroaqua Complexes [M3S4(H2O)9?xClx](4?x)+ (M = Mo, W; x = 4, 6, 7) and Their Supramolecular Compounds with Cucur[8]uril

Compounds of trigonal cluster chloroaqua complexes with cucurbit[8]uril were synthesized by slowly evaporating HCl solutions of chalcogenides heterometallic cubane cluster complexes of molybdenum and tungsten with cucurbit[8]uril in air; the complexes were characterized by X-ray diffraction analysis: (H₃O)₈[Mo₃S₄(H₂O)_2.5Cl_6.5]₂Cl(PdCl₄)·(C₄₈H₄₈N₃₂O₁₆)· 29H₂O (a = 13.3183(17) Å, b = 13.7104(18) Å, c = 18.225(3) Å; α = 80.263(3)°, β = 77. 958(3)°, γ = 87.149(4)°, V = 3207.4(7) ų, space group P , Z = 1, ρ(calc) = 1.900 g/cm³), (H₃O)₄ [Mo₃S₄(H₂O)₃Cl₆]₂·(C₄₈H₄₈N₃₂O₁₆)₃·68H₂O (a = 21.413(6) Å, c = 49.832(10) Å; γ = 120°, V = 19788(8) ų, space group R , Z = 3, ρ(calc) = 1.695 g/cm³), (H₃O)₆ [Mo₃S₄(H₂O)₃Cl₆]₂Cl₂·(C₄₈H₄₈N₃₂O₁₆)·12H₂O (a = 15.881(2) Å, b = 17.191(2) Å, c = 23.276(4) Å; β = 98.865(15)°, V = 6278.7(15) ų, space group P2₁/c, Z = 2, ρ(calc) = 1.638 g/cm³), [W₃S₄(H₂O)₅Cl₄]₂·(C₄₈H₄₈N₃₂O₁₆)₃·35H₂O (a = 21.038(3) Å; α = 61.20(1)°, V = 6762.0(14) ų, space group R , Z = 1, ρ(calc) = 1.582 g/cm³). The [Mo₃S₄(H₂O)₃Cl₆]²⁻ anion complex was isolated as three geometrical isomers.Original Russian Text Copyright © 2004 by E. V. Chubarova, D. G. Samsonenko, H. G. Platas, F. M. Dolgushin, A. V. Gerasimenko, M. N. Sokolov, Z. A. Starikova, M. Yu. Antipin, and V. P. Fedin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1049–1058, November–December, 2004.     

La2O3,Y2O3-Mo次级发射材料研究

采用粉末冶金方法制备了La2O3，Y2O3-Mo次级发射材料，测试了各种材料的次级发射系数。结果表明在钼中加入稀土氧化物可以具有很好的次级发射性能。经过激活处理后，材料的最大次级发射系数均高于2．0，达到了材料使用要求的发射水平。应用扫描电镜(SEM)和光电能谱仪(XPS)研究了稀土元素在烧结体断口和发射前后在试样表面的分布情况。分析结果表明稀土元素易于在晶界处偏聚，且发射后试样表面稀土元素的相对浓度明显高于发射前的浓度。     

催化动力学法测定痕量钼的研究—盐酸联氨—Mo（Ⅵ）—邻菲罗啉—甲苯胺蓝体系

基于盐酸介质中和邻菲罗啉的存在下，钼催化盐酸联氨还原甲苯妥蓝褪色反应，建立了一种高灵敏，高选择性测定痕量钼的新方法。方法的检出限为７．６９×１０＾－７ｇ／Ｌ，线性范围０－０．１μｇ／２５ｍＬ，成功用于水和豆类中钼的测定。