Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
1992-04-03
2001-05-01
Miller, Edward A. (Department: 3641)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
C564S437000, C149S105000
Reexamination Certificate
active
06225503
ABSTRACT:
This invention is in the general area of explosive compounds and more particularly, in the area of highly insensitive, heat resistant nitro-organic explosives.
The United States Government has rights in this invention pursuant to Contract No. w-7405-ENG-48 between the United States Department of Energy and the University of California for the operation of the Lawrence Livermore National Laboratory.
BACKGROUND OF THE INVENTION
In recent times, 1,3,5-triamino-2,4,6-trinitro-benzene (TATB) has been in great demand as an explosive in some applications because of its high resistance to shock (insensitivity), its stability, its high density and its accelerated detonation characteristics relative to other conventional explosives such as TNT. A few methods for the preparation of diamino-trinitro-benzene, TATB or TATB-based explosives have been published.
U.S. Pat. No. 4,248,798, issued to Atkins et al., teaches a method for preparing penta-nitro-aniline and triamino-trinitro-benzene from trinitro-toluene.
U.S. Pat. No. 4,439,622, issued to Hansen et al., discloses a method of forming large crystals of 1,3,5-triamino-trinitro-benzene by aminating 1,3,5-trichloro-trinitro-benzene with a suitable aminating agent.
U.S. Pat. No. 3,985,595, issued to Benziger, discloses an insensitive plastic-bonded explosive consisting of a mixture of 90 wt % of triamino-trinitro-benzene and 10 wt % of a saturated copolymer of chloro-trifluoro-ehtylene and vinylidene fluoride and a method for its preparation.
In some instances, very fine particle size material with a surface area of the order of several square meters per gram is desirable. Normally, with most chemicals, small particle size material may be obtained by conventional purification methods known in the art such as precipitation, coprecipitation and the like. However, controlling the particle size or producing TATB of sub-micron particle size by the use of these conventional methods has not been heretofore possible because suitable solvents and techniques have not been available.
U.S. Pat. No. 4,032,377, ('377 patent), issued to Benziger, describes a method for the production of high-purity triamino-trinitro-benzene whereby 1,3,5-trichloro-benzene is nitrated to form 1,3,5-trichloro-2,4,6-trinitro-benzene followed by amination to triamino-trinitro-benzene in the presence of sufficient water to render the ammonium chloride byproduct semideliquescent. However, the '377 patent does not refer to any particle size desirable or achieved.
It would be desirable, therefore, to have available a method for the production of TATB of small particle size.
Accordingly, it is an object of the subject invention to provide an explosive composition with improved detonating characteristics.
Yet another object is to provide TATB of a high degree of purity and of small particle size.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
SUMMARY OF THE INVENTION
To achieve the foregoing and other objects and in accordance with the purpose of the present invention as embodied and broadly described herein, the present invention is directed to a method for the preparation of very small particle size, high purity 1,3,5-triamino-2,4,6-trinitro-benzene, TATB. One preferred embodiment of the subject method comprises dissolving TATB, obtained either commercially or prepared in the laboratory by known methods, in a suitable solvent, most preferably, dimethylsulfoxide (DMSO), making the solution alkaline by the addition of a suitable alkali to dissolve all of the TATB, completely neutralizing the solution by the addition of a suitable acid (when fine crystals of TATB product separate out), and collecting and washing the crystals. Suitable alkalis include but are not limited to sodium hydroxide, potassium hydroxide, ammonia solution, and the like. Suitable acids include but are not limited to mineral acids such as nitric acid, sulfuric acid, and hydrochloric acid.
The desired particle size of TATB may be varied by varying the concentration of the aqueous acid solution used and also by varying the rate and manner of mixing the components. Typically, a larger surface area is obtained by rapidly adding the TATB solution to a very dilute solution of the acid. Pipetting a solution of the acid into a moderately stirred solution of TATB yields a product with larger particle size.
According to another embodiment of the instant invention, commercially obtained TATB is dissolved in a suitable solvent such as DMSO, when the solution is heated to a temperature of about 180° C. to about 195° C., most preferably from about 182° C. to about 185° C., while vigorously stirring it to dissolve all of the TATB. The hot TATB solution is then delivered into vigorously stirred cold water and the solution allowed to cool as fine crystals of TATB product separate out. The crystals are collected and washed to remove residual solvent and other impurities that may be present.
REFERENCES:
patent: 3301904 (1967-01-01), Cryer
patent: 3715398 (1973-02-01), Kaufman
patent: 3985595 (1976-10-01), Benziger
patent: 4032377 (1977-06-01), Benziger
patent: 4180424 (1979-12-01), Reed et al.
patent: 4248795 (1981-02-01), Atkins et al.
patent: 4255358 (1981-03-01), Jones et al.
patent: 4439622 (1984-03-01), Hansen et al.
patent: 4481371 (1984-11-01), Benziger
patent: 4554031 (1985-11-01), Kerviel et al.
patent: 4564405 (1986-01-01), Pallanck
patent: 4604489 (1986-08-01), Kayser
patent: 4935544 (1990-06-01), Nielsen et al.
McGuire Raymond R.
Moody Gordon L.
Rigdon Lester P.
Daubenspeck William C.
Miller Edward A.
Moser William R.
The United States of America as represented by the United States
Valdes Miguel A.
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