초록 ▼

There is provided an improved method for making synthetic hydrotalcite by first reacting powdered magnesium oxide with a high surface area, transition alumina in a solution or suspension to form a meixnerite-like intermediate. This intermediate is then contacted with an anion source such as an acid,

There is provided an improved method for making synthetic hydrotalcite by first reacting powdered magnesium oxide with a high surface area, transition alumina in a solution or suspension to form a meixnerite-like intermediate. This intermediate is then contacted with an anion source such as an acid, and most preferably carbon dioxide, to form the layered double hydroxide which is separated from the suspension by filtering, centrifugation, vacuum dehydration or other known means. On a preferred basis, the transition alumina combined with activated magnesia consists essentially of an rehydratable alumina powder having a surface area of 100 m.sup.2 /g or greater. To make related double hydroxide compounds, still other reactants such as bromides, chlorides, boric acids, or salts thereof, may be substituted for the carbon dioxide gas fed into this suspension.

대표청구항 ▼

[ What is claimed is:] [1.] A method for making a layered double hydroxide powder comprising:(a) reacting at least one trivalent metal oxide powder and at least one divalent metal compound selected from the group consisting of a hydroxide, oxide, carbonate and mixtures thereof, in a carboxylic acid

[ What is claimed is:] [1.] A method for making a layered double hydroxide powder comprising:(a) reacting at least one trivalent metal oxide powder and at least one divalent metal compound selected from the group consisting of a hydroxide, oxide, carbonate and mixtures thereof, in a carboxylic acid and carboxylate ion-free, aqueous suspension to form a double hydroxide intermediate;(b) contacting the double hydroxide intermediate with an anion source to form a layered double hydroxide; and(c) separating the layered double hydroxide from the suspension. [2.] The method of claim 1 wherein the divalent metal compound is selected from the group consisting of: a magnesium oxide, hydroxide, carbonate and mixtures thereof, a zinc oxide-containing compound, a copper oxide-containing compound, a nickel oxide-containing compound, an iron oxide-containing compound, a calcium oxide-containing compound, a manganese oxide-containing compound and mixtures thereof. [3.] The method of claim 1 wherein the divalent metal compound is selected from the group consisting of a magnesium oxide, a magnesium hydroxide, a magnesium carbonate and mixtures thereof.