Process for preparing 4-aminodiphenylamine intermediates
View Patent ↗The invention is directed to a method of producing one or more 4-aminodiphenylamine intermediates comprising the steps: a. bringing an aniline or aniline derivative and nitrobenzene into reactive contact; and b. reacting the aniline and nitrobenzene in a confined zone at a suitable time and temperature, in the presence of a mixture comprising a strong organic base, or equivalent thereof, and an oxidant comprising hydrogen peroxide in an amount of from about 0.01 to about 0.60 moles of hydrogen peroxide to moles of nitrobenzene.
1. A method of producing one or more 4-aminodiphenylamine intermediates comprising the steps of:
a. bringing an aniline or aniline derivative and nitrobenzene into reactive contact; and
b. reacting the aniline and nitrobenzene in a confined zone at a suitable time and temperature, in the presence of a mixture comprising a strong organic base, and an oxidant comprising hydrogen peroxide in an amount of from about 0.01 to about 0.60 moles of hydrogen peroxide to moles of nitrobenzene.
2. The method of claim 1 wherein said intermediates are reduced to produce 4-aminodiphenylamine.
3. The method of claim 2 , wherein the 4-aminodiphenylamine produced is reductively alkylated to an alkylated derivative of the 4-aminodiphenylamine.
4. The method of claim 1 wherein said base is a quaternary ammonium hydroxide selected from the group consisting of tetramethylammonium hydroxide, tetrabutylammonium hydroxide, methyltributylammonium hydroxide, benzyltrimethylammonium hydroxide, tricaprylmethylammonium hydroxide, cetyltrimethylammonium hydroxide and choline hydroxide and equivalent quaternary ammonium alkoxides, acetates, carbonates, bicarbonates, cyanides, phenolics, phosphates, hydrogen phosphates, hypochlorites, borates, hydrogen borates, dihydrogen borates, sulfides, silicates, hydrogen silicates, dihydrogen silicates and trihydrogen silicates.
5. The method of claim 1 wherein said hydrogen peroxide is supplied as an aqueous solution comprising from about 3 wt. % to about 5 wt. % hydrogen peroxide.
6. The method of claim 4 wherein said organic base is tetramethylammonium hydroxide.
7. The method of claim 4 wherein the intermediates are reduced to produce 4-aminodiphenylamine and base is recycled from the products of the reduction reaction, alone or with make-up quantities of fresh base or purified recycle base or both, for use in the reaction of said method.
8. The method of claim 6 wherein the hydrogen peroxide is supplied as an aqueous solution comprising from about 3 wt. % to about 7 wt. % hydrogen peroxide in an amount of from about 0.01 to about 0.5 moles of hydrogen peroxide to moles of nitrobenzene.
9. The method of claim 6 wherein the hydrogen peroxide is supplied as an aqueous solution comprising from about 15 wt. % to about 25 wt. % hydrogen peroxide in an amount of from about 0.01 to about 0.45 moles of hydrogen peroxide to moles of nitrobenzene.
10. The method of claim 6 wherein the hydrogen peroxide is supplied as an aqueous solution comprising from about 25 wt. % to about 40 wt. % hydrogen peroxide in an amount of from about 0.01 to about 0.35 moles of hydrogen peroxide to moles of nitrobenzene.
11. The method of claim 6 wherein the intermediates are reduced to produce 4-aminodiphenylamine and base is recycled from the products of the reduction reaction, alone or with make-up quantities of fresh base or purified recycle base or both, for use in the reaction of said method.
12. The method of claim 11 wherein the hydrogen peroxide is supplied as an aqueous solution comprising from about 20 wt. % to about 40 wt. % in an amount of from about 0.01 to about 0.2 moles of hydrogen peroxide to moles of nitrobenzene.
13. The method of claim 12 wherein the hydrogen peroxide is provided in an amount of from about 0.06 to about 0.21 moles of hydrogen peroxide to moles of nitrobenzene.
14. The method of claim 12 wherein the hydrogen peroxide is provided in an amount of from about 0.08 to about 0.17 moles of hydrogen peroxide to moles of nitrobenzene.
15. The method of claim 11 , wherein the hydrogen peroxide is supplied as an aqueous solution comprising from about 3 wt. % to about 7 wt. % in an amount of from about 0.01 to about 0.20 moles of hydrogen peroxide to moles of nitrobenzene.
16. The method of claim 15 wherein the hydrogen peroxide is provided in an amount of from about 0.03 to about 0.16 moles of hydrogen peroxide to moles of nitrobenzene.
17. The method of claim 15 wherein the hydrogen peroxide is provided in an amount of from about 0.06 to about 0.12 moles of hydrogen peroxide to moles of nitrobenzene.
18. The method of claim 4 wherein the intermediates are reduced to produce 4-aminodiphenylamine, and base in the products of the reduction reaction is purified to remove some or all of the quaternary ammonium salt impurities formed in the reactions of said method and reduction reactions, and is recycled for use in said method as the sole base or in combination with unpurified recycle base and/or with make-up quantities of fresh base.
19. The method of claim 18 wherein purified recycle base is used as the sole base or with make-up quantities of fresh base and the nitrobenzene feed time is about 100 minutes or less.
20. The method of claim 4 wherein the reaction temperature is from about 65° C. to about 90° C.
21. The method of claim 1 wherein said hydrogen peroxide is fed at a variable rate such as to optimally match the reaction kinetics for formation and disappearance of the Meisenheimer complex made from nitrobenzene and aniline.
22. The method of claim 1 wherein said oxidant is introduced into said confined zone after the start of nitrobenzene being introduced into said confined zone, or the introduction of said oxidant into said confined zone is completed before the completion of nitrobenzene being introduced into said confined zone, or both.
23. The method of claim 22 wherein said hydrogen peroxide is fed at a variable rate to optimally match the reaction kinetics for formation and disappearance of the Meisenheimer complex made from nitrobenzene and aniline.
24. The method of claim 1 wherein nitrobenzene and aniline react to form a Meisenheimer complex and said oxidant is introduced into said confined zone at the point where the concentration of said Meisenheimer complex is the highest.
25. The method of claim 24 , wherein the point of entry of said oxidant into said confined zone is at or near the point of entry of nitrobenzene.