Aluminum carboxylates

The development of new aluminum carboxjiates is evident in the literature. However, sales volume has decreased or the number of suppliers has been concentrated to such an extent that the U.S. International Trade Commission now reports data only for aluminum tristearate (867 t at 1.34/kg) (1). The aluminum carboxjiates of most commercial interest according to the trade literature (2,3) are given in Table 1. 

Aluminum Salts of Low Molecular Weight Carboxylic Acids 

Monobasic aluminum acetate (eg, aluminum subacetate), aluminum formoacetate, normal aluminum formate, and basic aluminum formate have found widespread use as mordants in dyeing, in the formulation of waterproofing compositions for textiles, and for dermatological treatment. 

The greatest industrial consumption of monobasic aluminum acetate has been as a solution in the preparation of red color lakes for the dyeing of cotton. Formation of a water-resistant coating on fabrics, paper, leather, or other materials is also an important application. In this process, for example, cloth is dipped into a solution of water-soluble soap, then into the aluminum salt solution, forming an insoluble, water-resistant aluminum soap coating on the fiber surfaces (10). 

Freshly prepared aluminum subacetate is also used to cross-link acid-hydrolyzed, coUagen-derived protein. This procedure is useful in the food, pharmaceutical, and photographic industries (11). 

Aluminum salts of carboxylic acids, aluminum carboxylates, may occur as aluminum tricarboxylates (normal aluminum carboxylates), Al(OOCR)2 monohydroxy (monobasic) aluminum dicarboxylates, (RCOO)2Al(OH) and dihydroxy (dibasic) aluminum monocarboxylates, RCOOAl(OH)2. Aluminum carboxylates are used in three general areas textiles, gelling, and pharmaceuticals. Derivatives of low molecular weight carboxyUc acids have been mainly associated with textile appHcations those of fatty carboxyUc acids are associated with gelling salts and more complex carboxylates find appHcations in pharmaceuticals. 

Name CAS Regis tryNum ber Fmpirical formula Molwt Mp, °C 

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This group of aluminum carboxylates is characterized mainly by its abiUty to gel vegetable oils and hydrocarbons. Again, monocarboxylate, dicarboxylate, and tricarboxylate salts are important. The chemical, physical, and biological properties of the various types of aluminum stearates have been reviewed (29). Other products include aluminum palmitate and aluminum 2-ethylhexanoate (30). 

Monohydroxyaluminum distearate, (HO)Al(OOC(CH2) gCH2)2, used to be the largest selling aluminum carboxylate (1). Although stiU sold, the product is no longer Hsted in the U.S. International Trade Commission Report (1) because of low volume or confidentiahty constraints because of too few supphers. Aluminum distearate is a white powder that is insoluble in water, alcohol, and ether. A key property is its abiUty to gel vegetable oils and hydrocarbons. Aluminum distearate is prepared by the reaction of aqueous sodium stearate with aqueous aluminum sulfate or chloride at pH 7.3. Aluminum monostearate is formed if the sodium stearate solution is held at pH 9.5 (44). 

Aluminum Acetates" in ECT 1st ed. under "Aluminum Compounds," Vol. 1, pp. 626 —627, "Aluminum Formates" in ECT 1st ed. under "Aluminum Compounds," Vol. 1, pp. 630—632, by Benjamin Toubes, Victor Chemical Works, "Aluminum Acetate" in ECT 2nd ed. under "Aluminum Compounds," Vol. 2, pp. 11—13, by Albert Stewart, MaUinckrodt Chemical Works, "Aluminum Formate" in ECT 2nd ed. under "Aluminum Compounds," Vol. 2, pp. 14—17, by Benjamin Toubes, Victor Chemical Works, a Division of Stauffer Chemical Company, "Aluminum Carboxylates" in ECT 3rd ed. under "Aluminum Compounds," Vol. 2, pp. 202—209, by Glenn H. Warner, Union Carbide Corporation. 

Kirk-Othmer Encyclopedia of Chemical Technology Wiley New York, 1978, 3rd Ed, Vol 2, 202 "Aluminum Carboxylates" and Vol 8, 34 "Driers and Metallic Soaps". 

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