Aluminum alcoholate

Oxidation of the trialkylaluminum to aluminum alcoholates and subsequent hydrolysis into the wanted alcohols and aluminum hydroxide... 

It has been shown recently (10) that such block structures could be tailored precisely by the general method summarized hereabove. It is indeed possible to convert the hydroxyl end-group of a vinyl polymer PA (f.i. polystyrene, or polybutadiene obtained by anionic polymerization terminated with ethylene oxide),into an aluminum alcoholate structure since it is well known that CL polymerizes in a perfectly "living" manner by ring-opening insertion into the Al-0 bond (11), the following reaction sequence provides a direct access to the desired copolymers, with an accurate control of the molecular parameters of the two blocks ... 

Kagan and coworkers studied the reaction between cyclopentadiene and 310 in the presence of aluminum alcoholates of chiral diols and their chiral mono ethers208. Among the various diols studied, only 1,1-diphenyl-1,2-propanediol (325) gave satisfactory results. Optimization by variation of the dienophile/catalyst ratio, aging of the catalyst and variation of the temperature ultimately resulted in a maximum of 86% ee at —100 °C. 

Preparation of (—)-Citronellol from Optically Active Pinenes. (+)-ci5-Pinane is readily synthesized by hydrogenation of (+)-0 -pinene or (+)-/3-pinene, and is then pyrolyzed to give (+)-3,7-dimethyl-l,6-octadiene. This compound is converted into (-)-citronellol (97% purity) by reaction with triisobutylalumi-num or diisobutylaluminum hydride, followed by air oxidation and hydrolysis of the resulting aluminum alcoholate [50]. 

In the Meerwein-Fonndorf reduction, cinnamaldehyde is reduced to cinnamic alcohol (yield ca. 85%) with isopropyl or benzyl alcohol in the presence of the corresponding aluminum alcoholate. 

In trying to formulate a reaction mechanism for the catalysis, the well known reaction of aluminum alcoholates with carboxylic anhydrides was used as a basis (14). For example, phthalic anhydride, maleic anhydrides, and carbon dioxide, will react so that the acid anhydride pushes itself between the metal atom and the alkoxy groups, thus separating them. This results in forming neutral aluminum salts of the monoalkyl carboxylic acids. It is possible, of course, for the conversion to proceed incompletely, having two alkoxy groups bound to the aluminum, thus having only 1 mole of acid anhvdride react on 1 mole of aluminum alcoholate. 

Owing to its high organic content, the anion is soluble in the mixture of excess alcohol and monoalkylphthalic acid. The formation is stimulated by the tendency of the electron deficient aluminum to form an octet. The formation of such anions with tetravalent aluminum is certain for the aluminum alcoholates. 

The salts of 3-acetyl-18p-glycyrrhetinic acid can be prepared by reaction between 3-acetyl-18p-glycyrrhetinic acid and an aluminum alcoholate. Preferably lower alcoholates are used, i.e., alcoholates in which the alkoxy group or groups have from one to four carbon atoms. The salification reaction may be carried out at room temperature or at an elevated temperature in conventional fashion, preferably in the presence of organic solvents. As organic solvents may be used alcohols, ethers, ketones, chlorinated solvents (methylene chloride, chloroform) ethyl acetate, etc. 

The re-etherification of boratrane with triethoxysilane in the presence of catalysts (aluminum alcoholates) in boiling xylene can yield hydridsila-trane ... 

Higher aluminumtrialkyls are used in the production of primary higher fatty alcohols. This presupposes the oxidation of aluminumtrialkyls and the hydrolysis of the aluminum alcoholates formed. 

A third, very important source of aluminum oxide hydoxides is the hydrolysis of aluminum alcoholates. Due to the high purity of the alcoholate, almost no impurities, except for carbon residues at low concentrations, are present in the product ... 

Raw material bauxite aluminum salt solutions aluminum alcoholates... 

It was observed479,480 that starch retards precipitation of Al(OH)3 formed from aluminates. This effect is caused by chemisorption and formation of a colloidal suspension, and is useful in organic synthesis, as in Meerwein-Pondorff-Verley redox reactions with aluminum alcoholates. 

Liquid phase modifications. Alternatively a porous membrane can be reduced in pore size by a liquid deposition prcx ess where the membrane is dipped into a solution or sol to form deposits inside the membrane pores. For example, a silicon nitride tube with a mean pore diameter of 0.35 pm is first immersed in a solution of aluminum alcoholate (aluminum isopropylate or 2aluminum tris(ethyl acetoacetate) or ethyl acetoacetate aluminum diisopropylate) in an organic solvent (hexane, cyclohexane, benzene, isopropanol, etc.). It is then treated with saturated water vapor to hydrolyze the alcoholate or chelate to form bochmite inside the pores, thus changing the pore diameter to as small as 20 nm [Mitsubishi Heavy Ind., 1984a and 1934b]. Upon calcining at 800X, boehmite transforms into transition-alumina. 

Tishchenko, W. The effect of aluminum alcoholates on aldehydes. The ester condensation as a new condesationform of aldehydes. Chem. Zentr. 1906, II, 1309-1311. 

The CONDEA group operates two different types of processes for the manufacture of alkoxide derived alumians and related products, the Ziegler-ALFOL process and CONDEA s On-Purpose Process. The Ziegler process is a co-production process of linear fatty alcohols and alumina, using aluminum organic compounds as intermediates, CONDEA s own On-Purpose technology is based on the formation of aluminum alkoxide from aluminum metal and alcohol. In both processes the formation of alumina is achieved by hydrolysis of aluminum alcoholates with water. 

Deviations from this general behavior are found with various alkyl aluminum alcoholates. Since alkoxy ions, OR, are stronger Lewis bases than the halogen ions, the Lewis acidity of the dialkylalkoxy alanes formed with the hypothetical Lewis acid R2A1+ (32) is low, i.e., there is little tendency to form complexes with weak bases. Accordingly, diethylaluminum alcoholate forms stable salts with potassium and cesium fluoride but not with sodium fluoride. The tendency to form complexes (e.g., with KF and NaH) increases in going from R2A10R to RAl(OR)2 (Fig. 9) (156, 322). Thus the... 

Alkyl aluminum halides and alkyl aluminum alcoholates are also inactive as catalysts for the ligand exchange between trialkyl boranes (133). 

The oxidation of trialkyl alanes with molecular oxygen has long been known (301, 312). Aluminum alcoholates are formed, from which alcohols are readily obtained by hydrolysis ... 

In general all A1—H and A1—C bonds in organoaluminum compounds react quantitatively at or below room temperature with water and alcohols to form compounds with A1—O bonds. Thus trialkyl alanes with alcohols produce aluminum alcoholates and alkanes. Reaction between water or most of the lower alcohols (methanol, ethanol) and trialkyl alanes with small alkyl groups is usually explosive if the undiluted components are mixed at room temperature. If certain safety precautions are observed, however, it is possible to carry out the hydrolysis (or deuterolysis for analytical purposes) so as to obtain the corresponding hydrocarbons. Ether solutions are particularly advantageous as the etherates of trialkyl alanes react less vigorously than the free compounds. 

Dorox . [Cond Cbemie GmbH] Aluminum alcoholates, alkenyl succinic anhydride, or derivs. for mfg. of pharmaceuticals, agrochemicals, dyes, fuel and lubricant additives. 

Whitaker, G. C., Aluminum alcoholates and the commercial preparation and uses of aluminum isopropylate, in Metal Organic Compounds. Advances in Chemistry Series. No. 23, pp. 184-189, Sept. 1959. 

That the intermediate product obtained when ethylene is formed is not the bulk aluminum alcoholate as Sabatier ) believed, was proved by the author and Shchekin 174) aluminum alcoholate decomposes under different conditions and gives other products than alcohol in catalysis on alumina. 

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