Catalytically highly effective precious metal-carboxylate compounds of Ir, Ru, Rh, Pd and Au
Processes produce catalytically highly effective noble metal carboxylate compounds or their solutions that comprise A) a noble metal carboxylate, wherein the noble metal is selected from the group consisting of ruthenium, platinum, palladium, rhodium and gold, and B) at least one compound selected from the group consisting of oxalic acid, a salt of oxalic acid, a derivative of oxalic acid and a salt of the derivative of oxalic acid. The process digests the noble metal with alkaline earth peroxide to produce a digestion mass and dissolves the digestion mass in a carboxylic acid or a carboxylic acid diluted with a protic solvent to produce a resulting solution, whereby alkaline earth ions are separated off as salt of an oxalic acid or salt of oxalic acid derivatives, and the processes do not include any BaSO4 precipitation and filtration of barium sulphate.
1. A process for the production of catalytically highly effective noble metal acetate compounds or their solutions, wherein the catalytically highly effective noble metal acetate compounds or their solutions comprise A) a noble metal acetate, wherein the noble metal is selected from the group consisting of ruthenium, platinum, palladium, rhodium and gold, and B) at least one compound selected from the group consisting of oxalic acid, and a salt of oxalic acid, said process comprising:
mixing the noble metal with an alkaline earth peroxide to produce a mixture;
heating the mixture consisting of the noble metal and the alkaline earth peroxide to produce a melt exhibiting the noble metal and the alkaline earth peroxide;
dissolving the melt exhibiting the noble metal and the alkaline earth peroxide in an acetic acid or an acetic acid diluted with a protic solvent to produce a resulting solution;
introducing an oxalic acid into the resulting solution; and
precipitating alkaline earth ions off the resulting solution as salt of an oxalic acid to produce a noble metal acetate compound or a noble metal acetate solution, wherein a proportion of alkaline earth metal in the noble metal acetate compound or the noble metal acetate solution amounts to 100 ppm to 10% by weight, based on the noble metal, following the precipitation as the alkaline earth salt of oxalic acid,
wherein the process does not include any BaSO4 precipitation and filtration of barium sulphate.
2. The process according to claim 1 , wherein the noble metal is ruthenium or iridium.
3. The process according to claim 1 , wherein the alkaline earth ions are selected from the group consisting of Calcium, Barium and Strontium.
4. The process according to claim 1 , wherein the protic solvent is water or an alcohol.
5. The process according to claim 1 , wherein is the alkaline earth peroxide is calcium peroxide or barium peroxide.
6. The process according to claim 1 , wherein the proportion of alkaline earth metal in the noble metal acetate compound or the noble metal acetate solution amounts to 500 ppm to 0.5% by weight, based on the noble metal, following the precipitation as alkaline earth salt of oxalic acid or salt.