Explosive and thermic compositions or charges – Containing nitrated organic compound
Reexamination Certificate
2001-03-14
2003-07-15
Hardee, John (Department: 1751)
Explosive and thermic compositions or charges
Containing nitrated organic compound
Reexamination Certificate
active
06592692
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an energetic plasticizer used in an insensitive high performance explosive and a propellant, and a preparation method thereof.
BACKGROUND OF THE INVENTION
Bis (2,2-dinitropropyl) formal (BDNPF) is a potent plasticizer used in an insensitive high performance explosive and propellant. However, it has an inherent disadvantage that it is solid at room temperature such that it can not be independently used. Thus, as a plasticizer, an eutectic mixture of BDNPF with its homologue is used.
U.S. Pat. No. 5,648,556 disclosed a plasticizer comprising an eutectic mixture of BDNPF/A, bis(2,2-dinitropropyl) formal/acetal, in which BDNPA keeps BDNPF from crystallizing out. The plasticizer comprising an eutectic mixture of BDNPF/A has been commercially available and wildly used in an explosive and a propellant. But, it is well known that thermal/chemical stability of an acetal group in the BDNPA is lower than that of the formal group in the BDNPF.
U.S. Pat. No. 4,997,499 disclosed a 2-components mixed-formal, BDNPF and 2,2-dinitropropyl 2,2-dinitrobutyl formal (DNPBF), in which DNPBF was used as an inhibitor of crystallization of BDNPF. The 2-components mixed-formal is obtained by reacting a mixture of 2,2-dinitropropanol and 2,2-dinitrobutanol with formaldehyde, but it is also known that about 10% of bis(2,2-dinitropropyl) diformal is always produced as an unfavorable side product.
The 2-components mixed-formal is believed to be superior to the BDNPF/A in terms of the thermal and chemical properties and cost involved. Nevertheless, it has never been realized in the formulation of an explosive and a propellant. It is expected that this is resulted from the difficulty of process, additional synthesis of 2,2-dinitrobutanol, the reduction of the energy efficiency.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an improved energetic plasticizer having excellent thermal and chemical properties as well as being economic.
Another object of the present invention is to provide a method for preparing the plasticizer.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided an energetic plasticizer comprising eutectic mixture of bis(2,2-dinitropropyl) formal (BDNPF) and bis(2,2-dinitropropyl) diformal (BDNPDF), wherein BDNPDF keeps BDNPF from crystallizing out.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates to an energetic plasticizer comprising eutectic mixture of bis(2,2-dinitropropyl) formal (BDNPF) and a material that keeps BDNPF from crystallizing out, wherein the material that keeps BDNPF from crystallizing out is bis(2,2-dinitropropyl) diformal (BDNPDF). More specifically, the present invention relates to an energetic plasticizer comprising eutectic mixture of BDNPF and BDNPDF, wherein the BDNPDF keeps BDNPF from crystallizing out. The amount of BDNPDF used in the energetic plasticizer is preferably in the range of 8~44% by mole, based on the mixture of BDNPF and BDNPDF. The amount of BDNPF used in the energetic plasticizer is preferably in the range of 92~56% by mole, based on the mixture of BDNPF and BDNPDF.
The plasticizer of the present invention can be achieved by suitably adjusting the amount of the formaldehyde with which 2,2-dinitropropanol is reacted to form a reaction mixture comprising BDNPF and BDNPDF. More specifically, it can be achieved by slowly adding a concentrated sulfuric acid solution to a solution in which 2,2-dinitropropanol and 1~3 equivalent of paraformaldehyde or s-trioxane is dissolved in methylene chloride, wherein the methylene chloride solution is maintained at a temperature of −30~20° C., extracting mixed formals from the obtained reaction mixture, and purifying the mixed formals.
Reaction of 2,2-dinitropropanol with formaldehyde is shown in scheme 1:
The plasticizer of the present invention in which BDNPDF prevents BDNPF from crystallizing out is not crystallized even though it stands at the temperature −20° C. for more than 6 months, while its thermal and chemical properties are similar to that of conventional plasticizer. Also, by using BDNPDF, that has been considered as a by-product, as an inhibitor of crystallization, no additional process is required to remove BDNPDF. Moreover, the cost involved is lower.
REFERENCES:
patent: 4594430 (1986-06-01), Grakauskas et al.
patent: 4997499 (1991-03-01), Adolph
patent: 5449835 (1995-09-01), Hamilton et al.
patent: 5648556 (1997-07-01), Hamilton et al.
US Statutory Invention Registration No. H350 (published Oct. 6, 1987) Adolph, et al.
Cho Jin Rai
Kim Jin Seuk
Lee Keun Deuk
Park Bang Sam
Agency For Defense Development
Hardee John
Scully Scott Murphy & Presser
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