Anhydrous Aluminum Bromide

CAUSES BURNS, REACTS VIOLENTLY WITH WATER Physical Properties 

Extinguish fire with carbon dioxide, dry chemical, or foam. Do not use water.2 

Violently decomposed by water with evolution of hydrogen bromide.2 Soluble in benzene, toluene xylene, nitrobenzene, and hydrocarbon solvents.1 

Dust irritates mucous membranes and causes painful eye burns. Interaction with moisture on the skin results in heat and acid burns. Swallowing causes severe burns. Avoid breathing dust. Prevent contact with skin and eyes.2 TLV-TWA 2 mg(Al)/m3.4 

Wear nitrile rubber gloves, laboratory coat, and eye protection. Cover the spill with a 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand. Scoop the mixture into a plastic pail and, in the fume hood, very slowly add the mixture to a pail of cold water. Allow to stand for 24 hours. Test pH of the solution and neutralize if necessary with sodium carbonate. Decant the solution to the drain with at least 50 times its volume of water. Treat the solid residue as normal refuse.5 7 The area of the spill should be washed thoroughly with soap and water.2 

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Anhydrous aluminum bromide, AIBr., forms colorless trigonal crystals and exists in dimeric form, in the crystal and Hquid phases (1). Dissociation... 

Boron tribromide [10294-33A], BBr, is used in the manufacture of diborane and in the production of ultra high purity boron (see Boron, ELEMENTAL BoRON COMPOUNDS). Anhydrous aluminum bromide [7727-15-3], AIBr., is used as an acid catalyst in organic syntheses where it is more reactive and more soluble in organic solvents than AlCl. Tballium bromide [7789AOA], TlBr, is claimed as a component in radiographic image conversion panels (39). 

Colorless, crystalline, anhydrous aluminum bromide supplied by the Westvaco Chemical Division, Food Machinery and Chemical Corporation, New York, New York, was used. When dissolved in dry benzene at room temperature with mechanical stirring, a perfectly clear yellow solution results, if the reagents are of high purity. 

Anhydrous aluminum bromide, 2 385 Anhydrous aluminum chloride, 2 357, 379-384... 

Reactions, e.g., with alkyl halides in ether using Ziegler-Natta catalyst form alkyl aluminum halides, R3AI2X3, [R2A1X]2 and [RA1X]2 with bromine vapor forms anhydrous aluminum bromide,... 

Dypnone has been prepared by the action of sodium ethoxide,1 aluminum bromide,2 phosphorus pentachloride,3 aluminum triphenyl,4 zinc diethyl,5 calcium hydroxide,6 anhydrous hydrogen chloride,5,7 aluminum chloride,4 and aluminum terf.-butoxide8 on acetophenone. It has been prepared by the action of aniline hydrochloride on acetophenone anil followed by treatment with hydrochloric acid.9 The preparation of aluminum ferJ.-butoxide has been described8,10 (p. 8). The procedure described is a modification of that by Adkins and Cox.8... 

The hot cyclohexane layer is carefully decanted, and the aluminum bromide layer is extracted with five 200-ml. portions of hot cyclohexane. Ether (400 ml.) is added to the cooled cyclohexane extracts (Note 11), and the combined solvent fractions are washed with two 100-ml. portions of water and dried over anhydrous magnesium sulfate. Evaporation of the solvent leaves a semi-solid residue that is partially dissolved in about 100 ml. of pentane. The undissolved white solid, diamantane, is collected by suction filtration. Additional diamantane is obtained by concentrating the pentane solution to a small volume and collecting the solid that precipitates. The total amount of diamantane obtained, after drying, is 60-62 g. (60-62%), m.p. 240-241° (closed tube) (Note 12). This product is sufficiently pure for most purposes, but it may be purified further by recrystallization from pentane to give white crystals, m.p. 244.0-245.4°. 

Reaction of anhydrous aluminum bromide with a series of 2,2,6,6-tetramethylpi-peridinoaminoboron bromides in dichloromethane leads to specific displacement of bromide, which is trapped as tetrabromoaluminate. By formation of this less nucleophilic anion, and owing to the steric and electronic shielding of the p atom by the bulky 2,2,6,6-tetramethylpiperidino moiety, dicoordinate borenium ions 231 are generated [Eq. (4.157)]. 

From ethylene and hydrogen bromide at —78° in the presence of anhydrous aluminum bromide. Tulleners, Tuyn, and Waterman, Rec. trav. chim. 53, 549 (1934). 

Anhydrous aluminum chloride can be prepared by the action of dry chlorine on aluminum in its properties it is very similar to aluminum bromide, which is the subject of the next preparation. 

Suggest a method of making anhydrous aluminum bromide, using hydrogen bromide instead of bromine, and state why you think the method might be feasible. 

What results from a treatment of perfluorocyclobutene with anhydrous aluminum chloride (compound S) or aluminum bromide (compound T) ... 

SYNS ALL iMINUM BROiMIDE, anhydrous (UN 1725) pOT) ALUMINUM BROMIDE, solution (UN 2580) pOT) ALUMINUM TRIBROMIDE TRIBROMOALUMINUM... 

Preparation (simplified procedure).10 A mixture of 168.5 g of anhydrous aluminum bromide and 940 g. of dry aluminum chloride is refluxed for 45 min. and let cool. Solid material is removed by filtration and the liquid is shaken with 170 ml. of 5% sodium carbonate solution and then with two 170-ml. portions of water. After drying with calcium chloride, fractionation with a 70-cm. Vigreux column gave a fore-run of 480 ml. of CCU and then 193 g. (51.4%) of pure bromotrichloromethane. b.p. 102-106°, 20d 1.5063. 

The alkylation of paraSins with olefins to yield higher molecular weight branched-chain paraffins may be carried out thermally or catalyt-ically. The catalysts for the reaction fall into two principal classes, both of which may be referred to as acid-acting catalysts (1) anhydrous halides of the Friedel-Crafts type and (2) acids. Representatives of the first type are aluminum chloride, aluminum bromide, zirconium chloride, and boron fluoride gaseous hydrogen halides serve as promoters for these catalysts. The chief acid catalysts are concentrated sulfuric acid and liquid hydrogen fluoride. Catalytic alkylations are carried out under sufficient pressure to keep at least part of the reactants in the liquid phase. 

The isomerization of butanes using a high vacuum technique for the purification and introduction of the reactants was investigated (Leighton and Heldman, 5). It was found that completely anhydrous aluminum bromide did not act as a catalyst for the isomerization at 85° the addition, however, of a small amount of hydrogen bromide to the reactants caused n-butane to isomerize. 

Recent experiments (Beeck el al., 25a) on the isomerization of propane-1-C to propane-2-C further demonstrate that the isomerization proceeds through an intramolecular rearrangement. No propane containing more than one C carbon atom per molecule was foimd. These experiments were made by contacting vapors of propane at approximately 25 and 450 mm. pressure with a catalyst prepared by the addition of 0.023 g. water to 0.40 g. anhydrous aluminum bromide for periods of time varying from 0 to 1074 hours. It was found that the rate of isomerization of propane-1-C to propane-2-C is comparable to the rate of isomerization of n-butane to isobutane under similar conditions. The equilibrium distribution of the propanes-l-C and -2-C was found to be statistical, that is, propane-l-OVpropane-2-C = 2. 

The experiments were made as follows 72 g. aluminum chloride or its equivalent as aluminum chloride-hydrocarbon complex were placed in the reactor, usually with 11. naphtha, and sealed into the reactor. Hydrogen was added in the higher temperature runs until the total reactor pressure was 41 atmospheres at room temperature. In experiments at 21°, anhydrous aluminum bromide was used as the catalyst in an effort to establish the equilibrium more rapidly. 

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