Enegetic hydrazinium salts

Details Enegetic hydrazinium salts Enegetic hydrazinium salts

1999-07-16

2001-04-17

Richter, Johann (Department: 7621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Amino nitrogen containing

Reexamination Certificate

active

06218577

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to hydrazine related salts particularly those of high energy.
2. Description of Related Art
Hydrazine is considered the state-of-the-art monopropellant for on-orbit satellite propulsion systems. However, a major drawback in the use of hydrazine resides in its inherent high vapor pressure at ambient temperatures resulting in high vapor toxicity. This toxicity results in a considerable investment in equipment and handling (safety requirements) to fuel and unload propulsion systems which incorporate hydrazine. Consequently, new ingredients are sought which can yield equivalent or superior specific impulse performance to that of hydrazine, yet have more desirable physical properties and significantly reduced toxicity.
Also heavy metal compounds have been targeted by both industry and government for reduction, and if possible, elimination of use. Certain explosives and initiators still contain heavy metals which can cause environmental and health concerns in their use and in their final disposal due to their inherent toxicity. Thus, there are environmental benefits to the use of these new salts as explosives or explosive ingredients.
In the prior art is U.S. Pat. No. 5,485,722 to Schmidt et al (1996), which discloses the decomposition of hydroxylammonium nitrate (HAN) monopropellant via metal catalyst. The disclosure pertains to monopropellant comprised of HAN as the primary component and suggests a list of possible organic or inorganic amine fuels as minor components. Included in the list of minor components is hydroxyethylhydrazinium nitrate (HEHN) but no results are noted with HEHN. While a HAN-based monopropellant can represent an approach to improved performance over hydrazine, experimental evidence shows such propellant is susceptible to a significant degree of thermal instability.
Also in the prior art is U.S. Pat. No. 5,433,802 to Rothgery et al (1995), which discloses the use of reduced volatility substituted hydrazine compounds in liquid propellants. The disclosure pertains to a liquid or gel bi-propellant comprised of an oxidizer, various nitrogen oxides or fuming nitric acid, and a fuel of a substituted hydrazine, with 2-hydroxyethylhydrazine being mentioned as a possible fuel. While this system can represent an approach to improved performance over hydrazine, it is a bi-propellant system, with fuel and oxidizer being held separately until their immediate use.
Accordingly there is need and market for a hydrazine replacement of reduced vapor toxicity that overcomes the above prior art shortcomings.
There has now been discovered a new energetic hydrazinium salts of such reduced toxicity, with enhanced stability and performance and method of making same.
SUMMARY OF THE INVENTION
Broadly, the present invention provides a method for preparing at least one hydroxyethylhydrazine (HEH) salt comprising, reacting the following:
HO—CH
2
—CH
2
—NH—NH
2
+m HX→[HO—CH
2
—CH
2
—NH
2
—NH
2
+
][X
−
] or [HO—CH
2
—CH
2
—NH
2
—NH
3
2+
][X
−
]
2
where HX=HNO
3
, HClO
4
, HN(NO
2
)
2
and HC(NO
2
)
3
and m=1 or 2.
The invention also includes the HEH salts so made.
Definitions:
By “30-100 wt %” acid concentration is meant acid in an aqueous solution up until 100 wt % when it becomes an anhydrous solution.
All %(s) herein are wt %(s) unless otherwise indicated
DETAILED DISCRIPTION OF THE INVENTION
The new salts were made by several different routes as discussed below. The general route is through an acid-base reaction in a polar solvent system between the relatively strong base, 2-hydroxyethylhydrazine and a strong acid of a desired energetic anion. The general reactions are as follows:
For 1:1 salts:
HO—CH
2
—CH
2
—NH—NH
2
+HX→[HO—CH
2
—CH
2
—NH
2
—NH
2
+
][X
−
] where HX=HNO
3
, HClO
4
, HN(NO
2
)
2
or HC(NO
2
)
3
For 1:2 salts:
HO—CH
2
—CH
2
—NH—NH
2
+2 HX→[HO—CH
2
—CH
2
—NH
2
—NH
3
2+
][X
−
]
2
where HX=HNO
3
or HClO
4
The above inventive reactions are suitably carried out in an inert, dry atmosphere,(nitrogen and argon are suitable materials) from −25° C. to +25° C. and in a polar solvent system which includes, methanol, ethanol, isopropanol, n-propanol, n-butanol, water or acetonitrile.
The following examples are intended to illustrate the invention and should not be construed in limitation thereof.


REFERENCES:
patent: 3297747 (1967-01-01), Thornton et al.
patent: 3314837 (1967-04-01), Heubusch
patent: 4310696 (1982-01-01), Hojo et al.

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