Metal oxides, physico-chemical properties

Through a co-assembling route, mesostructured lamellar molybdenum sulfides are formed hydrothermally at about 85 °C using cationic surfactant molecules as the templates. The reaction temperature and the pH value of the reaction system are important factors that affect the formation of the mesostructured compounds. The amount of the template and that of the S source are less critical in the synthesis of the compounds. For the three as-synthesized mesostructured materials, the interlayer distance increases linearly with the chain length of the surfactant. Infrared and X-ray photoelectron spectroscopy reveals that the individual inorganic layers for the three compounds are essentially the same both in composition and in structure. The formal oxidation state of the molybdenum in the materials is +4 whereas there exist S2 anions and a small amount of (S-S)2 ligands in the mesostructures. The successful synthesis of MoS-L materials indicates that mesostructured compounds can be extended to transition metal sulfides which may exhibit physico-chemical properties more diverse than non-transition metal sulfides because of the ease of the valence variation for a transition metal. 

By doping a primary catalyst component with lower-valent metal cations, additional oxygen vacancies will be created which facilitate the incorporation of electrophilic oxygen species chemisorbed on the surface into the bulk where they will not oxidize adsorbed methyl radicals. Also, the promoter oxide should be basic, not be reducible, oxidizablc, or easily volatiz-ablc. It should form a mixed oxide with the main component which may be possible if the ionic radii arc similar. According to these rules, the expert system proposes as potential catalyst components combinations of substances with appropriate chemical and physico-chemical properties (Table 2). Many of these systems already have been described in the literature... 

The literature was reviewed to describe the newest efforts to synthesize and characterize supported polynuclear metal complexes as adsorbents and catalysts. This review includes our attempts to model the equilibrium structures and properties of the metal complexes, using simple quantum mechanics, as a means to understand better the interactions between the surface and the metal complexes. Special attention is directed towards the characterization of the supported metal complexes before and after ligand removal. We compare these modeling results with observations in the literature so as to understand better the fundamental processes that govern the interactions between the metal complexes and the surfaces. With this enhanced understanding of these governing factors, it should be easier to prepare oxide solids decorated with metal complexes having the desired physico-chemical properties. 

The physico-chemical properties such as density, conductivity, and viscosity of the magnesium chloride electrolyte are of substantial importance for the current efficiency of the magnesium electrolysis. The solubility of the reaction products, Mg and CI2, in the electrolyte is also important to attain the high current efficiency. Interfacial properties between the Mg electrolyte and the metal may depend significantly on the oxide concentration of the bath. 

In the binary glass-forming systems of alkali metal borates, it is possible to observe change in the trend of a number of physico-chemical properties in the concentration range of approximately 20 mole % of alkali metal oxide. This phenomenon is known in the literature as boric acid anomaly , and it is due to the change in the structure of the B2O3 melt caused by the alkali metal oxide addition and is related to the ability of boron to change its coordination number. 

This book includes selected topics on the measurement and evaluation of physicochemical properties of molten electrolytes. It describes the features, properties, and experimental measurement of different physico-chemical properties of molten salt systems used as electrolytes for the production of different metals, metallic layer deposition, as a medium for reactions in molten salts, e.g. precipitation of double oxide powders used for functional and construction ceramics, special parts for steel and copper production, etc. 

Most trace metals can exist in more than one oxidation state and complexes of the same metal in different oxidation states differ in their physico-chemical properties. Care... 

Klabunde, K.J., Fazlul Hoq, M., Mousah, R, Matsuhashi, H. (1987) Metal Oxides and their physico-chemical properties in Catalysis and Synthesis. In Preparative Chemistry using supported reagents. Academic Press, London. 

Palm oil physico-chemical properties allow it to be the most widely fractioned oil (Table 2). Fractioning involves physical or chemical refine applying high temperatures, desodorisation and deacidification of oil under vacuum, in both cases. Physical deacidification accurs at 250-270 C under vacuum up to 3-5 Torr, whereas chemical uses 220-240 °C. The high temperatures and vacuum are necessary to remove undesirable compounds as traces of metals, free fatty acids, oxidation and decomposition products. Nevertheless, those procedures also remove some tocopherols and tocotrienols, and all carotenoids presented in the oil [30, 31, 32, 33,34]. 

This book presents coverage of the dynamics, preparation, application and physico-chemical properties of polymer solutions and colloids. It also covers the adsorption characteristics at and the adhesion properties of polymer surfaces. It is written by 23 contemporary experts within their field. Main headings include Structural ordering in polymer solutions Influence of surface Structure on polymer surface behaviour Advances in preparations and appUcations of polymeric microspheres Latex particle heterogeneity origins, detection, and consequences Electrokinetic behaviour of polymer colloids Interaction of polymer latices with other inorganic colloids Thermodynamic and kinetic aspects of bridging flocculation Metal complexation in polymer systems Adsorption of quaternary ammonium compounds art polymer surfaces Adsorption onto polytetrafluoroethylene from aqueous solutions Adsorption from polymer mixtures at the interface with solids Polymer adsorption at oxide surface Preparation of oxide-coated cellulose fibre The evaluation of acid-base properties of polymer surfaces by wettability measurements. Each chapter is well referenced. 

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