Precious metal compounds

A method of preparing tetraalkylammonium tetra- or hexa-hydroxy metallate of the formula (N(alkyl)4)y[M(OH)x], wherein

• M is a metal selected from the group consisting of rhodium, platinum, or palladium;
• alkyl is an alkyl group selected from the group consisting of ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, sec-pentyl, 3-pentyl, 2-methylbutyl, isopentyl, 3-methylbut-2-yl, 2-methylbut-2-yl, neopentyl, n-hexyl, 3-methylpentyl, isohexyl, neohexyl, 2,3-dimethylbutyl, and combinations thereof;
• Y is 2, or 3;
• and
• X is 6;
• said method comprising reacting hydroxy compounds of a metal selected from the group consisting of rhodium, platinum, or palladium with tetraalkylammonium hydroxide—optionally in the presence of a reaction medium.

A method for the production of an automobile exhaust catalyst, wherein a suspension containing a tetraalkylammonium tetra- or hexa-hydroxy metallate of the formula (N(alkyl)4)y[M(OH)x], wherein

• M is a metal selected from the group consisting of rhodium, platinum, or palladium;
• alkyl is an alkyl group selected from the group consisting of ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, sec-pentyl, 3-pentyl, 2-methylbutyl, isopentyl, 3-methylbut-2-yl, 2-methylbut-2-yl, neopentyl, n-hexyl, 3-methylpentyl, isohexyl, neohexyl, 2,3-dimethylbutyl, and combinations thereof;
• Y is 2, or 3;
• and
• X is and at least one substrate material is produced;
• by means of the reaction of the tetraalkylammonium tetra- or hexa-hydroxy metallate, the metal in the form of hydroxy compounds such as tetra- or hexa-hydroxy acids precipitates on the substrate material, and a catalyst support body is wholly or partially coated with the substrate material;
• and the hexahydroxy platinic acid applied to the substrate material is calcinated before or after the coating of the catalyst support body.