Aluminum oxide suspension

Stone, A.T., 1989a, Enhanced rates of monophenyl terephthalate hydrolysis in aluminum oxide suspensions. J, Colloid Interface Sci. 127 429-441. 

Favorable electrostatic interactions at the mineral-water interface can also result in the catalyzed hydrolysis of substrates (Mechanism 3). For example, hydrolysis rates of monophenyl terephthalate (MPT") in aluminum oxide suspensions were an order of magnitude greater than rates measured in homogeneous solutions (2.112) (Stone, 1989). 

Stone, A. T. 1988. The effect of Dismal Swamp dissolved organic matter on the adsorption and surface-enhanced hydrolysis of monophenyl terephthalate in aluminum oxide suspension, J. Colloid and Interface Sci., 132(l) 81-87. 

Mag nesia. ndAlumina. Suspension. A mixture of salts, available as Maalox, Mylanta, Gelusil, and Aludrox, contains magnesium hydroxide [1309-42-8] Mg(OH)2, and variable amounts of aluminum oxide in the form of aluminum hydroxide and hydrated aluminum oxide, ie, 2.9—4.2% magnesium hydroxide and 2.0—2.4% aluminum oxide, Al O, for a mixture of 4.9—6.6% combined magnesium hydroxide and aluminum oxide. This mixture may contain a flavoring and antimicrobial agents in a total amount not to exceed 0.5% (see Aluminum compounds, aluminum oxide). 

Polyhydric Alcohols. (Polyols). An alcohol with three or more hydroxyl groups, each attached to a different carbon atom. They are w-sol and of sweetish taste, which tends to intensify with increasing hydroxyl content. Examples of polyols of ordn interest are listed below. Polyvinyl alcohol is considered in a separate entry as a polymer although it is defined as a polyhydric alcohol. Polyols, when nitrated, make excellent expls, proplnt binders, plasticizers, etc. Prepn can follow the procedure of Lenth DuPuis (Ref 3) which uses a methanol suspension of either sucrose or dextrose and a special Cu-Al oxide catalyst to yield 60-65% distillable polyols at 240° and 1500psi Refs 1) Beil — refs found under individual compds 2) CA, under Alcohols, Polyhydric for compds of current ordn interest 3) C.W. Lenth R.N. DuPuis, "Polyhydric Alcohol Production by Hydrogenolysis of Sugars in the Presence of Copper-Aluminum Oxide , IEC 37, 152-57 (1945) CA 39, 1391 (1945)... 

High yields (76-81%) of alcohols are also obtained by adding solutions of acyl chlorides in anhydrous dioxane or diethyl carbitol to a suspension of sodium borohydride in dioxane and brief heating of the mixtures on the steam bath [751], by stirring solutions of acyl chlorides in ether for 2-4 hours at room temperature with aluminum oxide (activity I) impregnated with a 50% aqueous solution of sodium borohydride (Alox) (yields 80-90%) [1014], by refluxing acyl chlorides with ether solutions of sodium trimethoxyborohydride [99], or by treatment of acyl chlorides in dichloromethane solutions with tetrabutylammonium borohydride at —78° [771]. A 94% yield of neopentyl alcohol was achieved by the reaction of trimethylacetyl chloride with tert-butylmagnesium chloride [324]. 

A sulfuric acid solution of the oxide (25-75% solution) can be reduced with tin, copper, zinc, and other reducing agents forming a blue solution of molybdenum blue which are hydrous oxides of non-stoichiometric compositions (see Molybdenum Blue). Reduction with atomic hydrogen under carefully controlled conditions yields colloidal dispersion of compounds that have probable compositions Mo204(OH)2 and Mo40io(OH)2. Reduction with lithium aluminum hydride yields a red compound of probable composition MosOtIOEOs. Molybdenum(Vl) oxide suspension in water also can be reduced to molybdenum blue by hydriodic acid, hydrazine, sulfur dioxide, and other reductants. 

To a solution of 1 (7.0 g, 35 mmol) in absolute methanol (18 mL) and absolute ethyl ether (18 mL), cooled to — 78°C (dry ice-acetone), a solution of bromine (3 mL) in methanol (18 mL) was slowly added, and the reaction mixture was left at this temperature for 30 min. Ammonia was bubbled to reach pH 9, the mixture was allowed to attain room temperature and concentrated to dryness. The residue was dissolved in benzene (20 mL) and the suspension was Altered through a layer of aluminum oxide, and the filtrate was concentrated under reduced pressure to yield 2 (8.5 g, 60%), distilled at 105°C/0.05 torr, [a]D + 14° (c 1.3, CHClj). 

AH was prepared in the usual manner from a suspension of 2.0 g LAH in 75 mL anhydrous THF, cooled to 0 °C and well stirred in an inert atmosphere of He, and treated with 1.33 mL of 100% H2S04 added dropwise. There was added, drop-wise and over the course of 10 min, a solution of 3.1 g 3-ethylthio-4,5-dimethoxy-B-nitrostyrene in 15 mL anhydrous THF. At the end of the addition, the reaction mixture was returned to room temperature, and finally heated on the steam bath for 10 min. After cooling again, there was added enough IPA to decompose the excess hydride and sufficient 10% NaOH to convert the aluminum oxide to a white, easily filterable mass. This was removed by filtration, the filter cake washed with additional IPA, and the filtrate and washes combined and the solvent removed under... 

SYNTHESIS A solution of 16.9 g of ethyl 3,4,5-triethoxybenzoate in 25 mL THF was added to a well stirred suspension of 8 g LAH in 150 mL THF. The mixture was heated at reflux for 24 h and and, after cooling, treated with IPA to destroy the excess hydride. There was then added sufficient 25% NaOH to produce a granular, white form of the aluminum oxide. This was removed by filtration, the filter cake washed with IPA, and the filtrate and washes were combined and stripped of solvent... 

The activation of aluminum with ultrasound or dispersion of liquid aluminum. The suspension of powder aluminum in petrol or n-geptane without oxygen is subjected to ultrasound the tough oxide film on the surface of aluminum is removed and aluminum becomes reactive. The second activation technique is the dispersion of liquid aluminum with argon or purified nitrogen flow into a finely dispersed state. It should be noted, however, that the most reactive aluminum powder for direct synthesis is the powder alloyed with transition metals (titanium, zirconium, niobium, tantalum) with the size of particles from 10 to 125 pm. 

At our laboratory we have studied aluminum-oxide montmorillonite complexes prepared from ACH-solutions hydrothermally treated at temperatures up to 160 0 (9). Hydrothermal treatment of ACH at temperatures above about 120 0 yields positively charged, fibrillar boehmite in colloidal suspension (1 ). The size of the boehmite fibrils increases with increasing temperature and time of hydrothermal treatment. Ion-exchange of montmorillonite with these positively charged fibrils resulted in AMCs with... 

Niven S. E. H. and Moore R. M. (1993) Thorium sorption in seawater suspensions of aluminum oxide particles. Geochim. Cosmochim. Acta 57, 2169-2179. 

Hydroxytelluraxanthene 1.5 g(39 mmol) of lithium aluminum hydride is suspended in 100 ml of absolute diethyl ether, 9.24 g (30 mmol) of thoroughly ground teiluraxanthone are added in small portions to the stirred suspension kept at 20°, and the resultant mixture is stirred for 2 h. 100 ml of ethyl acetate are then added to the cooled, vigorously stirred reaction mixture, followed by a saturated aqueous ammonium chloride solution. The hydrolyzed mixture is filtered, the organic layer is separated, the aqueous phase is extracted twice with diethyl ether, and the organic solutions are combined, washed with water, dried with anhydrous sodium sulfate, filtered, and evaporated. The residue is chromatographed on aluminum oxide with benzene as the mobile phase yield 7.2 g (77%) m.p. 110 112°. 

The starting point for the suspension process is a finely divided aluminum oxide powder suspended in water. An additive provides the necessary viscosity. Spinning of this finely divided suspension with the help of additives provides raw aluminum oxide fibers, which by calcining and treatment at high temperature is converted into non-porous sintered a-aluminum oxide fibers. 

Aluminum interacts virtually only with hydrogen and oxygen, the latter existing in a form of aluminum oxide A1203—a strong chemical compound with a low degree of thermal dissociation. Usually, alumina is present in the metal in the form of fine-dispersed suspension of less than 1.0 pm [30],... 

Anderson, P. R., and M. M. Benjamin. 1990b. Modeling adsorption in aluminum-iron binary oxide suspensions. Envir. Sci. Technol. 24 1586-92. 

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