21世纪的钼化学品

叙述了面向 2 1世纪的钼化学品的研究与发展趋势。

常用钼化学品的生产应用现状

对常用钼化学品生产及研究现状进行了综述,并在此基础上对我国钼工业今后的发展进行了展望。

日用钼化学品的研究与开发

叙述了日用钼化学品，如皮肤－头发保护剂、沐浴液、眼影、冷烫液、消臭剂、除垢剂、漂白剂、消毒剂和洗涤剂等的研究与开发现状，预期日用钼化学品的应用前景引人。

^(95)Mo NMR谱及其在钼化学研究中的应用

对^（９５）ＭｏＮＭＲ的特点、提供的信息、发展历史以及研究现状作了较为全面的介绍。结合本实验室研究工作和部分文献报道对其在钼化学研究中的应用进行了较为详细的论述，同时还指出影响^（９５）ＭｏＮＭＲ的因素并进行了简单分类和讨论。

国内外钼化学制品概况

叙述了国内外钼化学制品近年来钼消费量及 2 0 0 2～ 2 0 0 4年预测、主要生产厂家、质量标准及中国与国外差距 。

电感耦合等离子体发射光谱法测定钼化学产品中的硫含量

提出了电感耦合等离子体发射光谱法测定钼化学产品中硫含量,优化了仪器硫元素的分析谱线,对最佳测定条件进行了试验探讨,验证了测定方法的准确性和稳定性。方法的检出限(3 s)为0.012 mg/L,方法的回收率在98.0%~104%之间,测定值的相对标准偏差(n=11)均小于4%。方法用于钼酸铵及高纯三氧化钼样品分析,所得结果与化学法测定结果相符合。方法简单实用,准确度高,能满足钼化学产品质量检验的需要。

化学沉积镍-钼-磷合金在NaCl溶液中的耐腐蚀性能

通过化学沉积获得不同晶态镍钼磷合金镀层,探讨了不同晶态及钼的添加量对化学沉积镍-钼-磷合金镀层在NaCl溶液中耐腐蚀性能的影响。结果表明:非晶态镀层有着较晶态镀层更好的耐蚀性能;磷含量一定时,钼的添加可较好地提高镀层的耐蚀性能。

1994年钼业年评

评述了1994年世界钼的需求、供给和价格，重点介绍钼的新产品，诸如合金钢、不锈钢、工具钢、轧辊钢以及各类钼的化学制品的研究与开发现状和进展。

Field Measurement of NO2 and RNO2 by Two-Channel Thermal Dissociation Cavity Ring Down Spectrometer

A two-channel thermal dissociation cavity ring down spectroscopy （CRDS） instrument has been built for in situ, real-time measurement of NO2 and total RNO2 （peroxy nitrates and alkyl nitrates） in ambient air, with a NO2 detection limit of 0.10 ppbv at 1 s. A 6-day long measurement was conducted at urban site of Hefei by using the CRDS instrument with a time resolution of 3 s. A commercial molybdenum converted chemiluminescence （Mo-CL） instrument was also used for comparison. The average RNO2 concentration in the 6 days was measured to be 1.94 ppbv. The Mo-CL instrument overestimated the NO2 concentration by a bias of ＋1.69 ppbv in average, for the reason that it cannot distinguish RNO2 from NO2. The relative bias could be over 100% during the afternoon hours when NO2 was low but RNO2 was high.

Preparation of TiO2/Bi2O3 Microfibers and Their Photocatalytic Activity

A series of TiO2/Bi2O3 heterojunction microfibers have been fabricated using cotton fibers as bio-templates, and characterized by XRD, SEM and UV-Vis techniques. Results reveal that Bi2O3 in the TiO2/Bi2O3 sample is assigned to monoclinic and tetragonal mix-crystal phase. Fibers lengths can reach several micrometers and diameters range from 0.5 μm to 3 μm. Compared with pure TiO2 and Bi2O3, TiO2/Bi2O3 samples display better absorption in visible light region. Photocatalytic activity was evaluated by degradation of MB under visible light irradiation. TiO2/Bi2O3 microfibers exhibite much higher activity than pure TiO2 and Bi2O3, and 22.84%TiO2/Bi2O3 can achieve the decomposition of about 95%MB, which is attributed to synergistic effects of the strong visible-light absorption of TiO2/Bi2O3 microfibers and the heterojunction formed between TiO2 and Bi2O3.

Effect of Molybdenum Doping on Oxygen Permeation Properties and Chemical Stability of SrCo0.8Fe0.2O3-δ

The phase composition, microstructure, thermal expansion coefficients, oxygen permeation properties and chemical stability of SrCo0.8Fe0.2O3-δ （SCFM） were investigated and compared with those of SrCo0.8Fe0.2O3-δ（SCF）. Single phase SCFM was successfully prepared by a combined EDTA-citric method. SCFM shows a lower thermal expansion coefficient （24× 10^-6-29× 10^-6/K） than SCF between 500 and 1050 ℃, indicating a more stable structure. SCFM shows a high oxygen permeation flux, although the oxygen flux of SCFM decreases slightly because of Mo dopant. Furthermore, it was demonstrated that the doping of Mo in SCF can prevent the order-disorder transition and improves the chemical stability to CO2.

相关行业信息

钼化学制品市场发展趋势浅析钼是钢铁、石油、化工等工业部门不可缺少的金属。随着科学技术的进步,钼的应用范围日趋扩大。目前钼主要用作合金添加剂,钼的化合物可用作催化剂,润滑剂、

Kinetics of oxidation roasting of molybdenite with different particle sizes

The kinetics of oxidation roasting of molybdenum concentrate was studied by differential thermal−gravimetric experiments and non-isothermal analysis methods.The results show that high temperature is beneficial for oxidation of molybdenum concentrate.The initial oxidation temperature of the molybdenum concentrate is 450℃,and the rapid oxidation occurs above 500℃.The oxidation process conforms to the unreacted shrinking nucleus model.The early stage of the oxidation is controlled by chemical reaction with the apparent activation energy of 123.180 kJ/mol,while the later stage is controlled by internal diffusion with the apparent activation energy of 80.175 kJ/mol.Moreover,the oxidation rate is closely related to particle size of the concentrate.The smaller the particle size is,the larger the oxidation rate is.

Effects of structures of molybdenum catalysts on selectivity in gas-phase propylene oxidation

Molybdenum-based catalysts for the gas-phase oxidation of propylene with air were investigated. Various types of silica-supported molybdenum oxide and molybdenum-bismuth mixed oxide cata- lysts were prepared from inorganic and organometallic molybdenum precursors using wet impregnation and physical vapor deposition methods. The epoxidation activities of the prepared cata- lysts showed direct correlations with their nanostructures, which were identified using transmission electron microscopy. The appearance of a partly or fully crystalline molybdenum oxide phase, which interacted poorly with the silica support, decreased the selectivity for propylene oxide for- mation to below 10%; non-crystalline octahedrally coordinated molybdenum species anchored on the support gave propylene oxide formations greater than 55%, with 11% propylene conversion. Electrochemical characterization of molybdenum oxides with various morphologies showed the importance of structural defects. Direct promotion by bismuth of the epoxidation reactivities over molybdenum oxides is disputed.

Roasting oxidation behaviors of ReS_2 and MoS_2 in powdery rhenium-bearing, low-grade molybdenum concentrate

The oxidation roasting process of molybdenum concentrate has significant advantages in industrial applications.However,utilization of low-grade mineral has many problems because it is more complex than the standard concentrate.In this study,the oxidation behaviors of powdery rhenium-bearing low-grade molybdenum concentrate were investigated through thermodynamic calculation,roasting experiments,thermogravimetric analysis,and phase analysis.The results obtained show that oxidation of MoS2 begins at 450℃,and MoO3 reacts with metal-oxide forming molybdate at 600℃.Finally,MoO3 can be dissolved in ammonia with a maximum content of approximately 80%.The volatile speed of Re was considerably slower than the oxidation speed of MoS2 because the nonvolatile products ReO2 and ReO3 were generated in reactions among MoS2,SO2,and Re2O7.The final volatilization rate of Re was almost 70%.This study determined the problems related to the roasting of low-grade molybdenum concentrate,which lays the scientific foundations for subsequent enhancement of molybdenum and rhenium extraction.

Effects of shape and size of second phase on mechanical properties of sintered Mo-Y_(2)O_(3) alloys

The morphology and size of second phase greatly influence the strengthening effect on oxidation dispersion strengthened Mo alloys.In this work,a novel nanostructuring strategy is adopted to modify the second phase of Y_(2)O_(3),and the corresponding effects of particle shape and size on mechanical properties of sintered Mo−Y_(2)O_(3) alloys were investigated.It is found that spherical particles with sizes below 200 nm are preferred due to the dominant intragranular distribution of second phases associated with better strengthening effect originating from dislocation pinning.With smaller particle size of Y_(2)O_(3) nanospheres(105 nm),the tensile strength of corresponding Mo alloy is enhanced by about 43.8%,much higher than that(8.3%)reinforced by second phase nanospheres with larger particle size(322 nm).Meanwhile,with similar particle size(around 100 nm),the spherical shape exhibits better strengthening effect than the one reinforced by one-dimensional rod-like second phase.

Synthesis and Characterization of Molybdenum（VI） Complexes with 1,10-Phenanthroline

The development of routes and strategies for the design and preparation of complexes of 4d metals in moderate oxidation states is of great importance in magnetochemistry, bioinorganic chemistry, materials chemistry and solid-state chemistry. Bidentate ligands containing N or O donors especially phenanthroline have been widely used to form complexes with interesting structural motif. Reaction of M（CO）6 （M = Cr, Mo, W） with phenanthroline has been done in 1935 and produced an interesting stereo structure, but the reaction of MoOE（acac）2 （acac = acetylacetonato） with phenanthroline has not been studied yet. So, in this research, first of all MoOE（acac） 2 was prepared, and then it reacted with bidentate nitrogen donor to lead to produce the complex of [MoOEL2] （L = Phen） and different aspects of this complex were studied. This complex is very active and highly selective epoxidation catalyst. The structure of the product was characterized by various spectral techniques such as elemental analysis, IH NMR, 13C NMR and IR spectroscopy.

Kinetics of 2-Methylbutene-2 Epoxidation with 2-Methylbutane Hydroperoxide

The kinetics of epoxidation of methylbutene with structurally identical methylbutane hydroperoxide was studied in the presence of a molybdenum catalyst. The analysis of the rate curves suggested the most probable scheme of the process. The revealed features of the process and its mathematical description make it possible to more competently design a reactor unit for the commercial production of isoprene according to the developed scheme. The main kinetic constants were calculated.

Conversion and reaction kinetics of coke oven gas over a commercial Fe-Mo/Al_2O_3 catalyst

Producing methanol from coke oven gas(COG) is one of the important applications of COG. Removal of sulfur from COG is a key step of this process. Conversion and reaction kinetics over a commercial Fe-Mo/Al2O3 catalyst(T-202) were studied in a continuous flow fixed bed reactor under pressures of 1.6-2.8 MPa, space time of 1.32-3.55 s and temperatures of 240-360 °C. Though the COG contains about 0.6 mol/mol H2, hydrogenation of CO and CO2 is not significant on this catalyst. The conversions of unsaturated hydrocarbons depend on their molecular structures. Diolefins and alkynes can be completely hydrogenated even at relatively low temperature and pressure. Olefins, in contrast, can only be progressively hydrogenated with increasing temperature and pressure. The hydrodesulfurization(HDS) of CS2 on this catalyst is easy. Complete conversion of CS2 was observed in the whole range of the conditions used in this work. The original COS in the COG can also be easily converted to a low level. However, its complete HDS is difficult due to the relatively high concentration of CO in the COG and due to the limitation of thermodynamics. H2 S can react with unsaturated hydrocarbons to form ethyl mercaptan and thiophene, which are then progressively hydrodesulfurized with increasing temperature and pressure. Based on the experimental observations, reaction kinetic models for the conversion of ethylene and sulfur-containing compounds were proposed; the values of the parameters in the models were obtained by regression of the experimental data.

Electrochemical Study of Trinuclear Metal Complexes ［M_3O_2（O_2CCH_3）_6（H_2O）_3］^（2＋）（M_3＝Mo_3，MoW_2，W_3）

In this paper detailed studies of the cyclic voltammetry(CV) of trinuclear metal cluster compounds [M_3O_2(O_2CCH_3,)6(H,O),j z+ (M,=Mo3,MoW2,W3) are reported.The result of CV shows that they are similar to each other.There are a reversible redox peak near-0. 48 V and an irreversible reduced peak near-1.10 V in the scan range of + l.0 V to l. 5 V.It implies that the M_3O_2,clusters might gain one electron to be further reduced.But the two-electron-reduced product of M_3O_2 clusters are instable.The theoretical calculations(EHMO) agree well with the result of the CV experiment.