加氢脱氮催化研究的新进展

化石燃料的加氢脱氮有利于改善油品质量及其稳定性,同时避免燃烧时NO_x的排放。本文介绍了不同化石燃料中有机氮化物的含量及类型,对不同加氢脱氮催化剂及其催化活性位的本质进行了探讨,同时论述了C—N键断裂机理及燃料中主要有机氮化物的HDN反应网络。着重概述了传统金属硫化物催化剂的改性方法,新型的金属碳化物、金属氮化物和金属磷化物催化剂的研究现状。     

Analysis of Corrosion Products Formed on Cu-Ni Alloys Immersed in Sea Water

Abstract

A method was developed for separation and analysis of corrosion products formed on the surface of Cu-Ni alloys immersed in sea water polluted by sulphide ions. This method is based on the selective dissolution of oxidation compounds by suitable solvents dissolving the metal matrix only to a negligeable extent.

The following solvents were used: 1) methanol to dissolve Na⁺, Cu²⁺, Ni²⁺ chlorides and sulphates; 2) glycine to dissolve bivalent metal compounds - Cu²⁺, Ni²⁺ oxides, sulphides, oxysulphates, oxychlorides and oxycarbonates; 3) ammonia solution to dissolve Cu⁺ compounds (i.e. Cu₂O and CuCl); 4) potassium cyanide to dissolve CU⁺ sulphides.

Reasonable agreement between chemical and X-Ray analysis results was observed only for copper compounds, since nickel and iron compounds could not tie observed by X-Ray diffraction. The results of Auger and chemical analyses better agree with each other, yet no Fe compounds could be detected. This is to be attributed to the non-homogeneous corrosion layer which notably contains Fe compounds in the innermost region at a depth where Auger spectroscopy is unable to detect them, whereas their detection is possible by chemical analysis, since it is a bulk analysis.     

Long-range magnetic ordering in Ba2CoS3: A neutron diffraction study

Neutron powder diffraction has been used to determine the magnetic structure of the quasi-one-dimensional compound Ba₂CoS₃, which contains linear [001] chains of vertex-sharing CoS₄ tetrahedra, spaced apart by Ba²⁺ cations. At 1.5 K the Co²⁺ cations in the chains are antiferromagnetically ordered with an ordered magnetic moment of 1.97(4) μ_B per cation aligned along [100]. Each Co²⁺ cation is ferromagnetically aligned with four cation in neighbouring chains and antiferromagnetically aligned with two others.     

Ein neuer Typ ternärer Cobaltsulfide A9Co2S7 (A \documentclass{article}\pagestyle{empty}\begin{document}$ \buildrel \wedge \over = $\end{document} K,Rb, Cs) mit trigonalplanaren [CoS3]-Baugruppen des zwei- und dreiwertigen Cobalts

A New Type of Ternary Cobalt Sulphide, A₉Co₂S₇ (A $ \buildrel \wedge \over = $ K, Rb or Cs), containing Trigonal-Planar [CoS₃] Units of Two- and Three-Valent Cobalt The passage of a stream of hydrogen over an alkali carbonate/cobalt/sulphur melt resulted in the preparation of the compounds K₉Co₂S₇, Rb₉Co₂S₇ and Cs₉Co₂S₇. The structure of the potassium compound (Space group P2₁3, Z = 4) could be determined from X-ray diffraction experiments on single crystals whilst X-ray investigations of powdered samples of the rubidium and caesium compounds indicate isotypic atomic arrangements with K₉Co₂S₇. The characteristic structural elements of these compounds are trigonal-planar [CoS₃]-units of two- and three-valent cobalt. The results from investigations of the magnetic properties of these ternary cobalt sulphides are in agreement with those expected for mixed-valent Co^II/Co^III structures. The analogously-composed ferrates are closely structurally-related to these sulphides and show corresponding magnetic properties [1].     

Oxidation of Metal Sulphides and Determination of Characteristic Temperatures by DTA and TG

The oxidation of metal sulphides and sulphide concentrates was studied by means of DTA, TG and DTG curves. The behaviour of ZnS, CdS, GaS, Tl₂S, Sb₂S₃ and Sb₂S₅ during thermal treatment in an oxidizing medium was investigated. The properties of these sulphides were compared and conclusions were drawn about their probable oxidation reactions and the kind of end-products obtained. The characteristic temperatures of the studied sulphides were determined on the basis of curves (DTA). The values obtained were used to compare the behaviour of the sulphides during the oxidation process in a fluid bed. The results can be used to improve the technological and economic indices in the industrial production of zinc. This revised version was published online in July 2006 with corrections to the Cover Date.     

GC behaviour of symmetrical n-dialkyl sulphides under isothermal and temperature programming conditions

Retention indices were determined for a homologous series of n-dialkyl sulphides on three stationary phases (SE-30, OV-17 and XE-60) under isothermal and linear temperature programming conditions. Under these two different GC conditions, equations were derived for each of the three stationary phases which showed the dependence of retention index on the number of carbon atoms and the boiling points for a homologous series of n-dialkyl sulphides. The equation for the correlation isothermal retention index was shown to be applicable to the identification of n-dialkyl sulphides using linear temperature programming. It was found that the GC behaviour of n-dialkyl sulphides makes these compounds suitable for use as a standard series instead of n-alkanes for the calculation of retention indices in GC analysis in which detectors insensitive to n-alkanes are employed. The use of the homologous series of n-dialkyl sulphides for the calculation of sulphide retention indices can be great practical importance in the microanalysis of natural compounds. We have used this method successfully in the analysis of pesticides containing S-atoms.     

三价砷阴离子AsS43-化合物[InAsS4(2,2'-bipy)]2的合成及性质

用水热法合成了含三价砷阴离子 AsS43-的化合物[InAsS4(2,2'-bipy)]2.该化合物晶体为单斜晶系,空间群为 P21/c,晶胞参数 a=0.89799(9)nm,b=2.1794(2)nm,c=1.43736(14)nm,β=91.274(2)°,V=2.8123(5)nm3.在此化合物中用金属螫合物[In(2,2'-bipy)]3+稳定了不常见的三价砷阴离子 AsS43-,讨论了金属价态对最终产物结构的影响,并且研究了该化合物的半导体性质(禁带带宽 1.35 ev).     

三价砷阴离子AsS43-的化合物[InAsS4(2，2’-bipy)]2的合成及性质

用水热法合成了含三价砷阴离子AsS3-4的化合物[InAsS4(2,2′-bipy)]2。 该化合物晶体为单斜晶系,空间群为P21/c,晶胞参数a=0.89799(9) nm,b=2.1794(2) nm,c=1.43736(14) nm,β=91.274(2)°,V=2.8123(5) nm3。 在此化合物中用金属螯合物[In(2,2′-bipy)]3+稳定了不常见的三价砷阴离子AsS3-4,讨论了金属价态对最终产物结构的影响,并且研究了该化合物的半导体性质(禁带带宽1.35 eV)。     

Solvothermal synthesis and characterisation of new one-dimensional indium and gallium sulphides: [C10N4H26]0.5[InS2] and [C10N4H26]0.5[GaS2]

Two new main group metal sulphides, [C₁₀N₄H₂₆]_0.5[InS₂] (1) and [C₁₀N₄H₂₆]_0.5[GaS₂] (2) have been prepared solvothermally in the presence of 1,4-bis(3-aminopropyl)piperazine and their crystal structures determined by single-crystal X-ray diffraction. Both compounds are isostructural and crystallise in the monoclinic space group P2₁/n (Z=4), with a=6.5628(5), b=11.2008(9), c=12.6611(9) Å and β=94.410(4)° (wR=0.035) for compound (1) and a=6.1094(5), b=11.2469(9), c=12.7064(10) Å and β=94.313(4)° (wR=0.021) for compound (2). The structure of [C₁₀N₄H₂₆]_0.5[MS₂] (M=In,Ga) consists of one-dimensional [MS₂]⁻ chains which run parallel to the crystallographic a axis and are separated by diprotonated amine molecules. These materials represent the first example of solvothermally prepared one-dimensional gallium and indium sulphides.