Use of a supported catalyst containing precious metal for oxidative dehydrogenation
The use of a supported noble metal catalyst obtainable by applying a sparingly soluble noble metal compound to a support from solution or suspension, and subsequently treating thermally, for preparing olefinically unsaturated carbonyl compounds.
1. A process for preparing olefinically unsaturated carbonyl compounds from olefinically unsaturated alcohols by oxidative dehydrogenation which comprises utilizing a supported silver catalyst, obtained by a process comprising
a) applying a complexed sparingly soluble silver compound to a support material from suspension or solution,
b) subsequently thermally treating the product obtained in stage a) at temperatures in the range from 100 to 400° C. over a period of 5 min to 5 h,
wherein the complexed sparingly soluble silver compound is complexed with a complexing agent selected from the group consisting of an amine- containing hydrocarbon, a hydroxyl-containing hydrocarbon, a carboxyl-containing hydrocarbon, ammonia, or oxo, aza or thio macrocycle, and
the sparingly soluble silver compounds used being those having a solubility in aqueous solution at a temperature of 25° C. and a pH of 7 of less than 5.0 g/l.
2. The process according to claim 1 , wherein the silver compound is applied in a mixture with additives which act as a promoter.
3. The process according to claim 1 ,
wherein 3-methylbut-2-en-1-al is the unsaturated carbonyl compound and is prepared from 3-methylbut-3-en-ol, which is the unsaturated alcohol.
4. A process for producing a supported silver catalyst for oxidative dehydrogenation of olefinically unsaturated alcohols, which comprises
a) applying a complexed sparingly soluble silver compound to a support material from suspension or solution, and then
b) thermally treating the product obtained in step a) at temperatures in the range from 100 to 400° C. over a period of 5 min to 5 h,
which forms the elemental noble metal from the silver compound by reduction,
wherein the complexed sparingly soluble silver compound is complexed with a complexing agent selected from the group consisting of an amine-containing hydrocarbon, a hydroxyl-containing hydrocarbon, a carboxyl-containing hydrocarbon, ammonia, or oxo, aza or thio macrocycle, and
the sparingly soluble silver compounds used being those having a solubility in aqueous solution at a temperature of 25° C. and a pH of 7 of less than 5.0 g/l, wherein the support material used is steatite.
5. The process according to claim 4 , wherein the silver compound is applied in a mixture with additives which act as promoters.
6. A supported silver catalyst having a specific resistivity of not more than 1000 mΩ*m, obtainable by
a) applying a complexed sparingly soluble silver compound to a support material from suspension or solution,
b) subsequently thermally treating the product obtained in step a) at temperatures in the range from 100 to 400° C. over a period of 5 min to 5 h,
wherein the complexed sparingly soluble silver compound is complexed with a complexing agent selected from the group consisting of an amine-containing hydrocarbon, a hydroxyl-containing hydrocarbon, a carboxyl-containing hydrocarbon, ammonia, or oxo, aza or thio macrocycle, and
the sparingly soluble silver compounds used being those having a solubility in aqueous solution at a temperature of 25° C. and a pH of 7 of less than 5.0 g/l;
wherein the support material is steatite.
7. The supported silver catalyst according to claim 6 , wherein the silver compound is applied in a mixture with additives which act as promoters.
8. A process for preparing olefinically unsaturated carbonyl compounds from olefinically unsaturated alcohols comprising:
a) applying a complexed sparingly soluble silver compound to a support material from suspension or solution,
b) subsequently thermally treating the product obtained in stage a) at temperatures in the range from 100 to 400° C. over a period of 5 min to 5 h to obtain a supported silver catalyst, and
c) oxidatively dehydrogenating the olefinically unsaturated alcohols utilizing the supported silver catalyst;
wherein the complexed sparingly soluble silver compound is complexed with a complexing agent selected from the group consisting of an amine-containing hydrocarbon, a hydroxyl-containing hydrocarbon, a carboxyl-containing hydrocarbon, ammonia, or oxo, aza or thio macrocycle, and
the sparingly soluble silver compounds used being those having a solubility in aqueous solution at a temperature of 25° C. and a pH of 7 of less than 5.0 g/l.
9. The supported silver catalyst according to claim 7 , wherein the promoters are alkali metals, alkaline earth metals or transition metals used in the form of halides, carboxylates or nitrates, or in the form of sulfur-containing anions.
10. The process according to claim 5 , wherein the promoters are alkali metals, alkaline earth metals or transition metals used in the form of halides, carboxylates or nitrates, or in the form of sulfur-containing anions.
11. The process according to claim 1 , wherein the support material is steatite.
12. The process according to claim 8 , wherein the support material is steatite.