Aluminum dehydrated

Synonym(s) Aluminum alumina fibre metana aluminum bronze aluminum dehydrated aluminum flake aluminum powder Aluminum trichloride trichloroaluminum0 aluminum chloride (1 3)... 

ALUMINA FIBRE ALUMINIUM BRONZE ALUMINUM FLAKE ALUMINUM 27 ALUMINUM AOO ALUMINUM DEHYDRATED ALUMINUM METAL (OSHA) ALUMINUM, molten (NA 9260) pOT) ALUMINUM POWDER ALUMINUM POWDER, coated (UN 1309) pOT) ALUMINUM POWDER, uncoated P N 1396) pOT) ALUMINUM PYRO POWDERS (OSHA) ALUMINUM WELDING FUMES (OSHA) AO A1 AR2... 

Synonyms cas 7429-90-5 aluminum dehydrated aluminumflake aluminum powder met ana aluminum... 

CAS 7429-90-5 EINECS/ELINCS 231-072-3 UN 1309 (DOT) UN 1396 (DOT) UN NA 9260 INS173 El73 Synonyms Aluminium Aluminum bronze Aluminum dehydrated Aluminum flake Aluminum metal Aluminum powder (INCI) Cl 77000 Pigment metal 1... 

Synonyms Aluminium Aluminum bronze Aluminum dehydrated Aluminum flake Aluminum metal... 

The widely used Moifatt-Pfltzner oxidation works with in situ formed adducts of dimethyl sulfoxide with dehydrating agents, e.g. DCC, AcjO, SO], P4O10, CCXTl] (K.E, Pfitzner, 1965 A.H. Fenselau, 1966 K.T. Joseph, 1967 J.G. Moffatt, 1971 D. Martin, 1971) or oxalyl dichloride (Swem oxidation M. Nakatsuka, 1990). A classical procedure is the Oppenauer oxidation with ketones and aluminum alkoxide catalysts (C. Djerassi, 1951 H. Lehmann, 1975). All of these reagents also oxidize secondary alcohols to ketones but do not attack C = C double bonds or activated C —H bonds. 

Many samples containing silicon also contain aluminum and iron. After dehydration, these metals are present as AI2O3 and Fe203. These oxides are potential interferents since they also are capable of forming volatile fluorides. 

Other Higher Oleiins. Linear a-olefins, such as 1-hexene and 1-octene, are produced by catalytic oligomerization of ethylene with triethyl aluminum (6) or with nickel-based catalysts (7—9) (see Olefins, higher). Olefins with branched alkyl groups are usually produced by catalytic dehydration of corresponding alcohols. For example, 3-methyl-1-butene is produced from isoamyl alcohol using base-treated alumina (15). 

Aluminum hydroxide and aluminum chloride do not ionize appreciably in solution but behave in some respects as covalent compounds. The aluminum ion has a coordination number of six and in solution binds six molecules of water existing as [Al(H20)g]. On addition of a base, substitution of the hydroxyl ion for the water molecule proceeds until the normal hydroxide results and precipitation is observed. Dehydration is essentially complete at pH 7. 

Further deprotonation, dehydration, and polymerization of monomers and dimers may yield ringlike stmctures of hydroxy—aluminum complexes (10). Coalescence of ring compounds into layers by further growth results in the formation of crystalline aluminum hydroxide at pH 6, the point of minimum aqueous solubiUty. 

Commercial grades of socbum aluminate contain both waters of hycbation and excess socbum hycboxide. In solution, a high pH retards the reversion of socbum aluminate to insoluble aluminum hycboxide. The chemical identity of the soluble species in socbum aluminate solutions has been the focus of much work (1). Solutions of sodium aluminate appear to be totaby ionic. The aluminate ion is monovalent and the predominant species present is deterrnined by the Na20 concentration. The tetrahydroxyaluminate ion [14485-39-3], Al(OH) 4, exists in lower concentrations of caustic dehydration of Al(OH) 4, to the aluminate ion [20653-98-9], A10 2) is postulated at concentrations of Na20 above 25%. The formation of polymeric aluminate ions similar to the positively charged polymeric ions formed by hydrolysis of aluminum at low pH does not seem to occur. Al(OH) 4 has been identified as the predominant ion in dilute aluminate solutions (2). 

Hydrates. Aluminum sulfate hydrates, Al2(SO H20, where n ranges from 0 to 27 have been reported (3—6). Relative decreasiag vapor pressure studies iadicate the presence of an octadecahydrate, hexadecahydrate, dodecahydrate, dihydrate, and the anhydrous salt, assumiag that basic aluminum sulfates are not formed duriag the dehydration (3). 

Potassium Aluminum Sulfate. Potassium aluminum sulfate [7784-24-9]. KAl(SO 12H20, is a white, astringent crystal known as potassium alum, ordinary alum, or potash alum. Its formula weight is 474.39 mp 92.5 °C sp gr 1.75 and solubiUty 11.4 g per 100 mL H2O at 20°C (8). It is soluble in dilute acid and insoluble in alcohol. It dehydrates at about 200 °C to porous desiccated potassium alum [10043-67-1], KAl(SO dried or burnt alum, which has a formula weight of 258.20. 

Sodium Aluminum Sulfate (SAS). Sodium aluminum sulfate is a dehydrated double salt of aluminum and sodium sulfate. It does not react with baking soda in cold, but in the heat of oven 1 mol of SAS produces 6 mol of carbon dioxide from reacting with baking soda. Historically, SAS was one of the first materials used to Hberate carbon dioxide from baking soda. Today its primary use is in household baking powder production. It is used either alone or in combination with MCP. SAS is not recommended for use in prepared mixes due to its lack of compatibiHty with other ingredients in a mix. 

Partially dehydrated derivatives complexed with polyethylene glycol or propylene glycol exist. In the United of hydration has been replaced by glycine are particularly popular. Aluminum zirconium tetrachlorhydrex gly antiperspinant products. 

The reaction is cataly2ed by all but the weakest acids. In the dehydration of ethanol over heterogeneous catalysts, such as alumina (342—346), ether is the main product below 260°C at higher temperatures both ether and ethylene are produced. Other catalysts used include siUca—alumina (347,348), copper sulfate, tin chloride, manganous chloride, aluminum chloride, chrome alum, and chromium sulfate (349,350). 

The vapor-phase esterification of ethanol has also been studied extensively (363,364), but it is not used commercially. The reaction can be catalyzed by siUca gel (365,366), thoria on siUca or alumina (367), zirconium dioxide (368), and by xerogels and aerogels (369). Above 300°C the dehydration of ethanol becomes appreciable. Ethyl acetate can also be produced from acetaldehyde by the Tischenko reaction (370—372) using an aluminum alkoxide catalyst and, with some difficulty, by the boron trifluoride-catalyzed direct esterification of ethylene with organic acids (373). 

Strong acids are able to donate protons to a reactant and to take them back. Into this class fall the common acids, aluminum hahdes, and boron trifluoride. Also acid in nature are silica, alumina, alumi-nosihcates, metal sulfates and phosphates, and sulfonated ion exchange resins. They can transfer protons to hydrocarbons acting as weak bases. Zeolites are dehydrated aluminosilicates with small pores of narrow size distribution, to which is due their highly selective action since only molecules small enough to enter the pores can reacl . 

Dehydration and dehydrogenation combined utihzes dehydration agents together with mild dehydrogenation agents. Included in this class are phosphoric acid, sihca-magnesia, silica-alumina, alumina derived from aluminum chloride, and various metal oxides. 

Cyclohexene can be prepared on a large scale still more rapidly and efficiently by the distillation of cyclohexanol over silica geP or, better, activated alumina. Using a 25-mm. tube packed with 8- to 14-mesh activated alumina (Aluminum Company of America) and heated to 380-450 over a 30-cm. length, 1683 g. of cyclohexanol was dehydrated in about four hours. After separating the water, drying with sodium sulfate, and fractionating with a simple column, 1222 g. (89 per cent yield) of cyclohexene, b.p. 82-84 , was obtained. 

Ethoxy-2-cyclohexenone is a useful intermediate in the synthesis of certain cyclohexenones. The reduction of 3-ethoxy-2-cyclohexenone with lithium aluminum hydride followed by hydrolysis and dehydration of the reduction product yields 2-cyclo-hexenone. Similarly, the reaction of 3-ethoxy-2-cyclohexenone with Grignard reagents followed by hydrolysis and dehydration of the addition product affords a variety of 3-substituted 2-cyclo-hexenones. ... 

A rather special procedure for the preparation of 21-hydroxy-20-ketopreg-nanes starts with the 17a-ethoxyethynyl-17 -hydroxy steroids described earlier. Free radical addition of ethanethiol to the triple bond, followed by acid-catalyzed hydrolysis and dehydration gives the 20-thioenol ether 21-aldehyde. This can be reduced with lithium aluminum hydride to the C-21 alcohol and then hydrolyzed to the C-20 ketone in the presence of mercuric chloride. The overall yield, without isolation of intermediates, is in the order of 50% ... 

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