Direct amination of hydrocarbons
A process for aminating hydrocarbons with ammonia in the presence of catalyst (i) which catalyzes the amination, which comprises supplying oxidizing agent to the reaction mixture and reacting the oxidizing agent with hydrogen which is formed in the amination in the presence of a catalyst (ii) which catalyzes this reaction with hydrogen.
1. A process for aminating at least one aromatic hydrocarbon with ammonia in the presence of a catalyst (i) which catalyzes the amination, which process comprises
supplying an oxidizing agent to a reaction mixture comprising the aromatic hydrocarbon and
reacting the oxidizing agent with hydrogen which is formed in the amination in the presence of a catalyst (ii) which catalyzes the reaction of the oxidizing agent with hydrogen.
2. The process according to claim 1 , wherein the aromatic hydrocarbon is first reacted with ammonia in the presence of the catalyst (i) and the oxidizing agent is then supplied to the reaction mixture.
3. The process according to claim 1 , wherein the aromatic hydrocarbon is first reacted with ammonia in the presence of the catalyst (i) and then, in the presence of the catalyst (ii), the hydrogen formed is removed from the reaction mixture with the oxidizing agent, wherein the hydrocarbon reacts with ammonia in the presence of the catalyst (i) during the hydrogen oxidation.
4. The process according to claim 1 , wherein the aromatic hydrocarbon is reacted with ammonia in the presence of the catalyst (i) in a first reaction chamber, then the oxidizing agent is supplied to the reaction mixture and, in a subsequent reaction chamber, the oxidizing agent is reacted with the hydrogen formed in the amination in the presence of the compound (ii) which catalyzes this reaction with hydrogen, wherein the hydrocarbon reacts with ammonia in the presence of the catalyst (i) during the hydrogen oxidation.
5. The process according to claim 1 , wherein the catalysts (i) and (ii) are each present in separate catalyst beds, the oxidizing agent is supplied to the reaction mixture upstream of a catalyst bed comprising the catalyst (ii), and the catalyst bed comprising the catalyst (ii) is followed by a catalyst bed comprising the catalyst (i).
6. The process according to claim 1 , wherein the catalyst (i) comprises compounds which comprise Ni, Co, Fe, Cu or combinations of these elements.
7. The process according to claim 1 , wherein the catalyst (i) comprises compounds which comprise Ni—Cu—X, Fe—Cu—X and/or Co—Cu—X, in which X is Ag or Mo.
8. The process according to claim 1 , wherein the catalyst (ii) comprises compounds comprising at least one of Pt and Pd, and Ag.
9. The process according to claim 1 , wherein the proportion by weight of the elements Ni, Co and Fe together in catalyst (i) is between 0.1% by weight and 75% by weight, and the proportion by weight of Cu is between 0.1% by weight and 75% by weight, based in each case on the total weight of catalyst (i).
10. The process according to claim 7 , wherein the proportion by weight of the doping element X in the total weight of the catalyst (i) is between 0.01% by weight and 8% by weight based on the total weight of the catalyst (i).
11. The process according to claim 8 , wherein the proportion by weight of Pt in catalyst (ii) is between 0.0001% by weight and 1% by weight, based on the total weight of catalyst (ii).
12. The process according to claim 1 , wherein a catalyst bed comprising catalysts (i) and (ii) is loaded with an hourly space velocity of from 0.1 to 5 kg of the aromatic hydrocarbon per liter of catalyst bed and per hour.
13. The process according to claim 1 , wherein the amination is performed continuously.
14. The process according to claim 1 , wherein hydrogen is removed physically from the reaction mixture.
15. The process according to claim 14 , wherein the amination is effected in a membrane reactor with integrated hydrogen removal by a hydrogen-permeable membrane.
16. The process according to claim 1 , wherein the amination is performed at temperatures between 200 and 800° C.
17. The process according to claim 1 , wherein the amination is performed at pressures between 1 and 900 bar.
18. The process according to claim 1 , wherein one molar equivalent of the aromatic hydrocarbon is reacted with one molar equivalent of ammonia to form one molar equivalent of an aminated aromatic hydrocarbon and one molar equivalent of hydrogen.
19. The process according to claim 1 , wherein the aromatic hydrocarbon is benzene and the amination forms aniline.
20. The process according to claim 1 , wherein the catalyst (i) comprises Mi, Cu, Zr and Mo, and the catalyst (ii) comprises Pt.