Solid aluminas

Figure 46. Typical bed collapse curve traced by optical-fiber probe tracking instrument (solids alumina A66, 140-280 microns). (Yang, Tung, and Kwauk, 1985.)...

Our catalyst for the isomerization of alkenes is going to be HC1 absorbed on to solid alumina (aluminium oxide, AI2O3) and the isomerization is to occur during a reaction, the addition of HC1 to an alkyne, in which the alkenes are formed as products. In this reaction the oxalyl chloride is first mixed with dried alumina. The acid chloride reacts with residual water on the surface (it is impossible to remove all water from alumina) to generate HC1, which remains on the surface. 

They consist of a thin layer (<10 fxm) of a nanoporous (3-1OA) carbon film supported on a meso-macroporous inorganic solid (alumina) or on a carbonized polymeric structure [15]. They are produced by pyrolysis of polymeric films. The following two types of membranes are produced ... 

Typical performance levels of an electron microprobe for quantitative analysis of a solid material correspond to a precision of around 1% for major elements and detection limits of approximately 100 to 500 ppm. Catalyst analysis poses specific problems because of the nature of the supports insulating, hydrated and porous. The precision of analysis for a catalyst is limited by the counting statistics to which is added an error due to the porous nature of the material (the signals measured on a porous alumina are, generally speaking, between 5 and 30% lower than those measured on a solid alumina). 

To a solution of 6 g (0.06 mol) of chromium trioxide in 11 mL of 6 N hydrochloric acid is added 4.75 g (0.06 mol) of pyridine within 10 min at 40 °C. The mixture is kept at 10 °C until a yellow-orange solid forms and then reheated to 40 °C to dissolve the solid. Alumina (50 g) is added with stirring at 40 °C. After evaporation in a rotary evaporator, the orange solid is dried in vacuo for 2 h at room temperature. The reagent can be kept under vacuum for several weeks in the dark without losing its activity. 

Another system for which both Ha and O2 production has been observed involves the use of RUO2 and [Ru(bipy)3] " cosupported on sepiolite combined with platinum deposited on Eu " embedded in alumina. The two solids, alumina and the clay, associate in solution to give a system as shown in Figure 12. Photolysis of this system produces hydrogen and oxygen in an oscillatory... 

In a related transformation, cyclopropanes 7 were obtained from active methylene compounds and electron-deficient alkenes by the action of iodine and potassium fluoride supported on solid alumina. 

Polymeric, solid ATPH was adapted for [4-i-2] cycloaddition [64]. The polymer catalyst 66 was prepared by treatment of MesAl with the appropriate biphenol, followed by exposure to ultrasonic irradiation, and could be recovered quantitatively by simple filtration and reused (Scheme 6.44). The activity of the recovered 66 did not decrease even after seven uses. It is worthy of note that the [4+2] addition competes wifh fhe Tischenko reaction, which is a major path when solid alumina catalysts are used. 

Table 1 Uses of Alumina Solid alumina Furnace components Catalyst substrates Electronics substrates Electrical insulators Cutting tools Bearings Spark Plugs Arc lamp tubes Laser hosts Gem stones Alumina powders Abrasives Catalyst pellets Alumina coatings Oxidation protection of aluminum and aluminum alloys Capacitors Transisitors Bioceramics Alumina fibers Thermal insulators Fire retardation Alumina as a component of...

Cell 20 [60]. Metal ions introduced into a solid -alumina lattice behave like ions in solution. This study illustrates a compact solid-state storage cell that can be charged using solar energy. During charging, Fe... 

The reaction without sonication or in the presence of a solvent is very slow. The authors state that a solid alumina surface and sonication are essential to promote the reaction. 

Once silica particles have been formed, the surface can be modified by the attachment of different atoms or groups to modify physical and chemical behavior. If the silica surface is completely covered with a layer of alumina even as thin as one or two molecules in thickness, for example, it then acts as though it were a solid alumina particle, bearing a positive charge and stable at low pH. 

Temperature of air around aluminum cell Temperature of boundary between graphite cathode and solid alumina Temperature of alumina melt Temperature of steel mantle of an aluminum cell... 

The sodium/sulfur battery operates around 570-620 K and consists of a molten sodium anode and a liquid sulfur cathode which contains a carbon fibre matrix for conduction. The anode and cathode are separated by a solid -alumina electrolyte (see Section 28.2). The cell reaction is ... 

In order to prepare the catalytic bed, the catalyst is dissolved in a low-boiling solvent (methylene chloride, methanol), the nucleophile salt (alkaline halide or carboxylate) or the inorganic base (NaHCO or porous inorganic solid (alumina or silica... 

Pyrimido(4, 5-d)pyrimidine derivatives were synthesized by an efficient, facile and solvent-free procedure. These are synthesized by the reaction between aromatic aldehydes, barbituric acid and urea/ thiourea under microwave irradiation. In this process, solid alumina was used as an energy transfer medium (Kategaonkar et al., 2009). 

---