Methods for producing aminonitrobenzoic acids
View Patent ↗Methods of producing aminonitrobenzoic acids are disclosed. A dinitrobenzoic acid may be reduced to an aminonitrobenzoic acid. In some specific embodiments, 2,6-initrobenzoic acid may be converted to 2-amino-6-nitrobenzoic acid. An end product may be used as an intermediate in the manufacture of various compounds including agricultural chemicals and pharmaceuticals.
1. A method for producing 2-amino-6-nitrobenzoic acid, comprising:
reacting 2,6-dinitrobenzoic-acid with a reducing agent under conditions sufficient to form 2-amino-6-nitrobenzoic acid in a reaction mixture comprising an alcohol and water in a ratio of about 9:5 (v/v) alcohol to water; and
isolating 2-amino-6-nitrobenzoic acid from the reaction mixture,
wherein the reducing agent is selected from the group consisting of sulfide, hydrosulfide and polysulfide.
2. The method according to claim 1 , wherein the reducing agent is sulfide.
3. The method of claim 1 , wherein the reducing agent is hydro sulfide.
4. The method of claim 1 , wherein the reducing agent is polysulfide.
5. The method of claim 3 , wherein the hydrosulfide is an alkali metal hydro sulfide.
6. The method of claim 5 , wherein the alkali metal is sodium.
7. The method of claim 1 , wherein the alcohol is selected from the group consisting of methanol, n-propanol, and isopropanol.
8. The method of claim 7 , wherein from about 1 to about 5 equivalents of reducing agent is used.
9. The method of claim 1 , wherein the reaction conditions comprise reflux temperature.
10. The method of claim 1 , further comprising producing the 2,6-dinitrobenzoic acid from dinitrotoluene.
11. A batch method of producing 2-amino-6-nitrobenzoic acid, comprising:
converting 2,6-dinitrobenzoic acid to 2-amino-6-nitrobenzoic acid in a single step transformation performed in a reaction mixture comprising an alcohol and water in a ratio of about 9:5 (v/v) alcohol to water; and
isolating the 2-amino-6-nitrobenzoic acid from the reaction mixture.
12. The batch method of claim 11 , wherein the conversion is facilitated by a reducing agent selected from the group consisting of sulfide, hydrosulfide and polysulfide.
13. The batch method of claim 11 , wherein the conversion is characterized by a yield of at least about 85%.
14. The method of claim 7 , wherein the alcohol is methanol.
15. The batch method of claim 11 , wherein the alcohol is methanol.
16. The method of claim 11 , further comprising producing a pharmaceutical, agricultural chemical, vitamin or dye from the isolated 2-amino-6-nitrobenzoic acid.