Sodium aluminium oxide

The main crystalline phases were identified (see Figs. 1 2) and the contents of amorphous material were determined from selected bed samples by XRD. Main crystalline phases are Ca9(Al 0 g) calcium aluminium oxide, Ca8,2sNai.5(Al60]g) calcium sodium aluminium oxide, calcium magnesium silicate (diopside), calcium phosphide, and magnesium silicate (enstatite). 

The chemicals used for the synthesis were the coimnercials, tetraethojgrsilane (TEOS, 99% (Assay) Aha Aesar), sodium chloride (NaCl Rectapur Prolabo), 1-Butyl-3-methylimidazolium methane sulfonate (Bmim) synthesized as proposed by Cassol et al. [9], sodium hydroxide pellets (NaOH, Merck) and sodium aluminium oxide (Aha Aesar). 

Aluminium oxide is a white solid, insoluble in water, with a very high melting point. If heated above red heat, it becomes insoluble in acids and alkalis, and can only be brought into solution by first fusing it with sodium or potassium hydroxide when an aluminate is formed. 

The starting material for the above step may be prepared as follows 5 g (0.016 mol) of N -(p-methoxyphenyl)-p-chlorobenzhydrazide hydrochloride and 4.75 g (0.018 mol) of benzyl levulinoyloxyacetate were heated In 25 ml of glacial acetic acid for 3 hours at 80°C. The solvent was then evaporated off under vacuum. The residue was taken up in chloroform and the solution was washed neutral by shaking with sodium bicarbonate solution and thereafter with water. After drying the chloroform solution, this was subjected to chromatography on aluminium oxide, the eluate was concentrated by evaporation and the viscous oil remaining as residue was crystallized by adding ether. The compound melted at 94°-95 t. The yield was 4.1 g which corresponds to 50.7% of the theoretical yield. 

If the preference for hydrogen ion exchange shown by lime-soda glasses can be reduced, then other cations will become involved in the ion exchange process and the possibility of an electrode responsive to metallic ions such as sodium and potassium exists. The required effect can be achieved by the introduction of aluminium oxide into the glass, and as shown in Table 15.2, this approach has led to new glass electrodes of great importance to the analyst. 

Still has also carried out mechanistic experiments9 3 from which he could deduce that the major reduction pathway is by attack of hydride ion at the sulphur atom. This conclusion was deduced from the fact that reduction with sodium borodeuteride-aluminium oxide gave a sulphoxide that had only incorporated about 25% mole equivalent of deuterium on to a methyl carbon atom bound to the sulphur atom. The mechanistic pathway for direct reduction is outlined in equation (38), whereas the pathway whereby deuterium could be incorporated is portrayed in equation (39). These reactions support the proposed mechanism for the hydride reduction of sulphones as outlined in Section III.A.l, namely that attack at sulphur by hydride ions may occur, but will be competitive with proton abstraction in cases when the attack at sulphur is not facilitated. 

The reagent can be used, for example, on aluminium oxide, silica gel, kieselguhr. Si 50000, RP and cellulose layers. Sodium molybdate-impregnated phases and zirconium oxide layers are also suitable [1]. 

There was a rather surprising instantaneous detonation when making an aluminium oxide/sodium nitrate mixture. 

Freeder, B. G. et al., J. Loss Prev. Process Ind., 1988, 1, 164-168 Accidental contamination of a 90 kg cylinder of ethylene oxide with a little sodium hydroxide solution led to explosive failure of the cylinder over 8 hours later [1], Based on later studies of the kinetics and heat release of the poly condensation reaction, it was estimated that after 8 hours and 1 min, some 12.7% of the oxide had condensed with an increase in temperature from 20 to 100°C. At this point the heat release rate was calculated to be 2.1 MJ/min, and 100 s later the temperature and heat release rate would be 160° and 1.67 MJ/s respectively, with 28% condensation. Complete reaction would have been attained some 16 s later at a temperature of 700°C [2], Precautions designed to prevent explosive polymerisation of ethylene oxide are discussed, including rigid exclusion of acids covalent halides, such as aluminium chloride, iron(III) chloride, tin(IV) chloride basic materials like alkali hydroxides, ammonia, amines, metallic potassium and catalytically active solids such as aluminium oxide, iron oxide, or rust [1] A comparative study of the runaway exothermic polymerisation of ethylene oxide and of propylene oxide by 10 wt% of solutions of sodium hydroxide of various concentrations has been done using ARC. Results below show onset temperatures/corrected adiabatic exotherm/maximum pressure attained and heat of polymerisation for the least (0.125 M) and most (1 M) concentrated alkali solutions used as catalysts. 

Aluminium Metal oxides Magnesium Metal oxides Potassium Metal oxides Sodium Metal oxides... 

Aluminium oxide exists in many crystalline modifications, usually designated by Greek letters, some with hexagonal and some with cubic lattices (cf. refs. 11 and 24). The best known and mostly used forms are a- and 7-alumina but practical catalysts are seldom pure crystallographic specimens. This makes the surface chemistry of aluminas rather complicated. Moreover, the catalytic activity of alumina depends very much on impurities. Small amounts of sodium (0.08—0.65%) poison the active centres for isomerisation but do not affect dehydration of alcohols [10]. On the other hand, traces of sulphates and silica may increase the number of strong acidic sites and change the activity pattern. 

J. J. Berzelius prepared lead phosphate by adding a soln. of lead acetate to a nitric acid soln. of bone-ash, and decomposed the lead phosphate by treatment with dil. sulphuric acid, and removed the last traces of lead by hydrogen sulphide and W. Odling treated a soln. of sodium phosphate in ice-cold water with lead acetate, and decomposed the washed precipitate suspended in water with hydrogen sulphide. The soln., freed from the precipitated lead sulphide, was evaporated to remove the hydrogen sulphide. J. Persoz digested the soln. of bone-ash with ferric or aluminium oxide, decomposed the precipitated phosphate with sulphuric acid, and afterwards extracted with phosphoric acid with alcohol. L. Thompson precipitated the lime by treating the calcium phosphate with oxalic acid. W. H. Ross and co-workers purified phosphoric acid by a process of fractional crystallization. 

In nature aluminium oxide is mostly mined as the minerals bauxite and laterite, but these as extremely impure. Most bauxite is purified according to the Bayer process which removes the oxides of iron(III), silica and titanium. This takes place by autoclaving the bauxite with sodium hydroxide and sodium carbonate. The precipitated aluminium hydroxide is subsequently heated, or calcined. Calcination involves a heat treatment of a powder as a result of which the latter breaks down ... 

Aluminium oxide is the oldest ceramic material used in medicine. Bauxite and corundum are the main natural sources of aluminium oxide. Bauxite is a mixture of diaspore, gibbsite, iron hydroxides, clay minerals and quartz. It is formed by the tropical weathering of silicate rocks during which quartz and the elements sodium, calcium, magnesium and potassium are largely washed away. This is the reason why the remaining material becomes richer in the resistant elements titanium, iron and aluminium. The latter is extracted from this mixture in the form of aluminium hydroxide. In its turn this compound is converted into aluminium oxide by heating the mixture to 1200-1300 °C, this is called calcination. The hydroxide is thus made anhydrous. 

Bauxite, an impure form of aluminium oxide, is first treated with sodium hydroxide to obtain pure aluminium oxide, removing impurities such as iron(m) oxide and sand. This improves the conductivity of the molten aluminium oxide. 

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