Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
1999-12-06
2001-07-31
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
C564S421000, C564S422000
Reexamination Certificate
active
06268536
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process for the conversion of a picrate salt, preferably ammonium pricrate, to useful chemical products, such as triaminophenol, triaminobenzene, picramic acid, and salts of picramic acid.
BACKGROUND OF THE INVENTION
There is a need to destroy, or reclaim, explosive materials as part of the demilitarization effort. Procedures conventionally used to demilitarize conventional munitions include incineration of reclaimed explosives and open burning or detonation. Some explosive materials, such as ammonium picrate, also known as Explosive “ID”, are of high enough purity to be economically suitable for conversion to higher value chemicals.
The destruction of nitrogen-containing explosives has been the subject of various disclosures. For example, German patent publication DE 413147-A1 discloses the hydrogenation of nitro-aromatic explosives in the presence of an alcohol solvent, hydrogen, and a catalyst at a temperature of about 40° C. to 100° C. Also, U.S. Pat. No. 4,661,179 discloses a process for destroying waste explosives containing nitro, nitrate, or nitroamino groups by hydrogenation. Further, U.S. Pat. No. 5,582,119 teaches a method for destroying explosive waste, such as those containing ammonium picrate, by use of a vessel containing a hot granular bed of sand to ignite the waste and to dampen explosive forces generated by its ignition.
U.S. Pat. No. 5,530,175 discloses a process for converting ammonium picrate to oxygenated products, particularly hydroquinone or cyclohexanediol and ammonia, by hydrogenation over a supported Group VIII metal catalyst. The ammonium picrate is dissolved in a suitable solvent, then hydrogenated at a temperature of about 25° to 250° C., followed by separation of the resulting products and ammonia.
It is also known in the art that ammonium picrate can be converted to picric acid by acidification with a strong acid, at an appropriate pH and acid/salt ratio in an aqueous system. The concentration of picric acid must be kept relatively low because as the concentration of picric acid increases, its rate of formation decreases.
While there exists methods for converting ammonium picrate to more useful products, such as to picric acid, there remains a need for processes that can do this conversion more efficiently and economically.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a process for converting ammonium picrate to triaminophenol which process comprises:
a) reacting the ammonium picrate with a strong inorganic acid in an aqueous medium, thereby producing picric acid and the ammonium salt of the strong acid;
b) separating said picric acid, from the ammonium salt, by dissolving it in an organic solvent; and
c) hydrogenating said picric acid with a hydrogenation catalyst at suitable conditions thereby converting the picric acid to picramic acid, triaminophenol, or both.
In a preferred embodiment of the present invention the triaminophenol is treated by removing the hydroxyl group from said triaminophenol by reacting it with a hydrogen-containing treat gas in the presence of a hydrotreating catalyst, at suitable hydrotreating conditions, thereby converting said triaminophenol to triaminobenzene.
In another preferred embodiment of the present invention the hydrotreating catalyst used in steps c) and d) is selected from those comprised of a Group VIII metal selected from Ni and Co, and a Group IV metal selected from Mo and W, on an inorganic refractory support.
REFERENCES:
patent: 4661179 (1987-04-01), Hunter et al.
patent: 5530175 (1996-06-01), Johnson et al.
patent: 5582119 (1996-12-01), Barkdoll
patent: 5990354 (1999-11-01), Goetsch
Arcuri Kym B.
Goetsch Duane A.
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