Aluminum magnesium hydroxy fatty acid compounds and thermostable

Abstract

A novel aluminum magnesium hydroxy fatty acid compound is disclosed having a general formula, Al.sub.x Mg.sub.y (OH).sub.3x+2y-z R.sub.z.nH.sub.2 O, wherein R is at least one aliphatic monocarboxylic acid group having the formula RCOO.sup.- and comprising from 12 to 22 carbon atoms, and wherein x=2, 2.ltoreq.y.ltoreq.10, z=2, and n is an integer greater than zero. The compound is prepared by a process including placing water and a salt which is one of an alkali metal salt or an ammonium salt of at least one aliphatic monocarboxylic acid having from 12 to 22 carbon atoms in a reactor fitted with heating and stirring means. The salt is dissolved by intensive stirring and by heating to a temperature ranging from 20.degree. to 90.degree. C. to provide a salt solution. The pH of the salt solution in the reactor is maintained at a pH of at least 8 to provide an alkaline solution. A solution comprised of water, an aluminum salt, and a magnesium salt is added to the reactor under constant stirring to cause reaction and precipitation of a precipitate comprised of the novel aluminum magnesium hydroxy fatty acid compound. The precipitate is separated and washed with substantially demineralized water until substantially no anions of the aluminum salt and the magnesium salt are detectable. A lipogel with improved thermal stability is formed using the novel compound and organic lipophilic compounds which are liquid at room temperature, and is useful in cosmetic or pharmaceutical preparations.