Method for producing a hydrazine composition

Abstract

This method involves reacting a mixture of hydrazine hydrate and hydroxyethylhydrazine with a nitrate to produce a product mixture containing hydrazine hydrate, hydrazinium nitrate, hydroxyethylhydrazine, and hydroxyethylhydrazinium nitrate, and then distilling the product mixture to produce a final mixture containing hydrazine, hydroxyethylhydrazinium nitrate, and hydrazinium nitrate.

Description

Background Art

[0001] A mixture of hydrazine, hydrazine nitrate, and hydroxyethylhydrazine nitrate serves as a low-vapor-toxicity alternative to pure hydrazine in end uses such as rocket propellants. Methods for producing such mixtures have mainly focused on mixing high-purity hydrazine, hydroxyethylhydrazine, and ammonium nitrate, and then removing ammonia by vacuum distillation and sparging with dry gas. However, the high cost of high-purity hydrazine and hydrazine nitrate results in a correspondingly high cost of the mixture.

Summary of the Invention

Means for Solving the Problems

[0002] A method according to an example of the present disclosure includes reacting a mixture of hydrazine hydrate and hydroxyethylhydrazine with a nitrate to produce a product mixture containing hydrazine hydrate, hydrazinium nitrate, hydroxyethylhydrazine, and hydroxyethylhydrazinium nitrate, and distilling the product mixture to produce a final mixture containing hydrazine, hydroxyethylhydrazinium nitrate, and hydrazinium nitrate.

[0003] In any further embodiment of any of the foregoing embodiments, the nitrate is selected from the group consisting of ammonium nitrate and nitric acid.

[0004] In any further embodiment of any of the foregoing embodiments, the nitrate contains ammonium nitrate.

[0005] In any further embodiment of any of the foregoing embodiments, the nitrate contains nitric acid.

[0006] In any further embodiment of any of the foregoing embodiments, the nitrate is ammonium nitrate.

[0007] In any further embodiment of any of the foregoing embodiments, the nitrate is nitric acid.

[0008] In further embodiments of any of the embodiments described above, a mixture of hydrazine hydrate and hydroxyethylhydrazine is produced by first reacting ethylene oxide with an excess of hydrazine hydrate to obtain an intermediate mixture containing hydrazine hydrate, hydroxyethylhydrazine, and bis(hydroxyethyl)hydrazine.

[0009] Further embodiments of any of the above embodiments include distilling the intermediate mixture to substantially remove bis(hydroxyethyl)hydrazine from the intermediate mixture to produce a mixture of hydrazine hydrate and hydroxyethylhydrazine.

[0010] In further embodiments of any of the embodiments described above, the molar composition of the final mixture is 50-75% hydrazine, 15-35% hydroxyethylhydrazinium nitrate, and 5-15% hydrazinium nitrate.

[0011] One example of a method according to the present disclosure involves reacting ethylene oxide with an excess of hydrazine hydrate to produce a mixture of hydrazine hydrate and hydroxyethyl hydrazine to produce an intermediate mixture containing hydrazine hydrate, hydroxyethyl hydrazine, and bis(hydroxyethyl)hydrazine; distilling the intermediate mixture to substantially remove bis(hydroxyethyl)hydrazine from the intermediate mixture to produce a mixture of hydrazine hydrate and hydroxyethyl hydrazine; reacting the mixture of hydrazine hydrate and hydroxyethyl hydrazine with a nitrate to produce a product mixture containing hydrazine hydrate, hydrazinium nitrate, hydroxyethyl hydrazine, and hydroxyethylhydrazinium nitrate; and distilling the product mixture to produce a final mixture containing hydrazine, hydroxyethylhydrazinium nitrate, and hydrazinium nitrate.

[0012] In further embodiments of any of the embodiments described above, the nitrate is selected from the group consisting of ammonium nitrate and nitric acid.

[0013] In further embodiments of any of the embodiments described above, the nitrate includes ammonium nitrate.

[0014] In further embodiments of any of the embodiments described above, the nitrate includes nitric acid.

[0015] In further embodiments of any of the embodiments described above, the nitrate is ammonium nitrate.

[0016] In any further embodiment of the above-described embodiments, the nitrate is nitric acid.

[0017] In any further embodiment of the above-described embodiments, the molar ratio of excess hydrazine hydrate to ethylene oxide is 2:1 to 9:1.

[0018] This disclosure may include, individually or in any combination, one or more of the individual features disclosed above and / or below.

[0019] Various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings accompanying the detailed description can be briefly described below. [Brief explanation of the drawing]

[0020] [Figure 1] This figure shows a method for producing a mixture of high-purity hydrazine, hydroxyethylhydrazine, and hydrazinium nitrate. [Modes for carrying out the invention]

[0021] Figure 1 schematically shows a method 10 for producing a low-cost mixture of high-purity hydrazine, hydroxyethylhydrazine, and hydrazinium nitrate. For example, this mixture can be produced from relatively low-cost raw materials, hydrazine hydrate and ethylene oxide. As shown in Figure 1, raw materials F1 of hydrazine hydrate (N2H4·H2O) and F2 of ethylene oxide (EtOH) are introduced into reactor 12. Raw materials F1 and F2 are supplied in a ratio that results in a molar excess of hydrazine hydrate, with a preferred ratio being 2 to 9 moles of hydrazine hydrate per 1 mole of EtOH (2:1 to 9:1). The resulting intermediate mixture F3 contains hydrazine hydrate and reaction products, hydroxyethylhydrazine (HEH), water (H2O), and bis(hydroxyethyl)hydrazine (Bis(HE)H), according to the following formula (I). The reaction conditions in reactor 12 can be optimized to maximize the yield of hydroxyethylhydrazine and minimize the amount of bis(hydroxyethyl)hydrazine produced as a byproduct, preferably in the range of a temperature of 30 to 100°C and a gauge pressure of 0.1 to 0.5 psi.

[0022] (Equation I) N2H4·H2O+EtOH→N2O4·H2O+HEH+H2O+Bis(HE)H The resulting intermediate mixture F3 is processed in one or more distillation columns 14. The distillate D1 discharged from the top of the distillation column 14 contains a mixture of hydrazine hydrate, hydroxyethyl hydrazine, and water, and is substantially free of the by-product bis(hydroxyethyl)hydrazine (preferably less than 1%). The by-product B1 is discharged from the bottom of the distillation column 14. By-product B1 is a mixture rich in bis(hydroxyethyl)hydrazine. If necessary, the mixture rich in bis(hydroxyethyl)hydrazine is further processed as a useful by-product or recycled as process fuel (e.g., burned to heat the distillation column 14).

[0023] The distillation mixture D1 of hydrazine hydrate, hydroxyethylhydrazine, and water obtained from the distillation column 14 is fed to the second reactor 16 where it is mixed with the nitrate feedstock F4. The nitrate feedstock F4 contains nitric acid or ammonium nitrate (AN). Either may be used, but ammonium nitrate facilitates reduction of side reactions in the reactor 14. Hydrazine hydrate and hydroxyethylhydrazine react with the nitrate to produce a product mixture F5 containing hydrazine hydrate, hydrazinium nitrate (HN), hydroxyethylhydrazine (HEH), and hydroxyethylhydrazinium nitrate (HEHN). The components of the product mixture F5 can be adjusted by controlling the ratio of the distillation mixture D1 to the nitrate feedstock F4. For example, this ratio, according to the following (Equation II), includes an equilibrium mixture of hydrazine hydrate, HN, HEH, HEHN, ammonia, ammonium nitrate, and water (i.e., a mixture in which the chemical species react with each other until an equilibrium distribution is established and thereafter the relative fractions that make up the mixture remain constant).

[0024] (Equation II) N2H4·H2O + HEH + H2O + AN → N2H4·H2O + HN + HEH + HEHN + NH3 + AN + H2O More specifically, the reaction of 4.4 molar parts of the distillate D1, containing 54.6% N2H4·H2O, 22.7% HEH, and 22.7% H2O in molar units, with 1 molar part of the feedstock F4 containing 100% ammonium nitrate produces an equilibrium product mixture F5 that approximately contains 44.0% N2H4·H2O, 0.8% HN, 0.1% HEH, 16.4% HEHN, 17.2% NH3, 4.2% AN, and 17.3% H2O in molar units. Since this reaction is not sensitive to either pressure or temperature, it can preferably be carried out at ambient temperature and pressure, or at a temperature and pressure close thereto.

[0025] Next, the product mixture F5 is processed in one or more distillation columns 18. The distillate D2 discharged from the top of the distillation column 18 substantially contains hydrazine hydrate, water, and ammonia (when ammonium nitrate is used as the nitrate source). When the components of the distillate D2 are removed, the equilibrium of the mixture remaining in the distillation column 18 changes, and the desired final mixture M of hydrazine, hydroxyethylhydrazinium nitrate, and hydrazinium nitrate is formed, which is discharged from the bottom of the distillation column 18 according to the following (Formula III) (due to its high basicity, substantially all is protonated to hydroxyethylhydrazinium nitrate, leaving only a negligible portion of hydroxyethylhydrazine). For example, considering that 10% of ethylene oxide is lost as bis(hydroxyethyl)hydrazine and 15% of hydrazinium nitrate is lost during distillation, a final mixture M with a molar composition of 65% hydrazine, 27% HEHN, and 8% HN is formed from 1.15 moles of hydrazine hydrate, 0.297 moles of ethylene oxide, and 0.350 moles of ammonium nitrate per mole of the final mixture M. In a further example, the final mixture M has a molar composition of 50 - 75% hydrazine, 15 - 35% hydroxyethylhydrazinium nitrate, and 5 - 15% hydrazinium nitrate.

[0026] (Formula III) N2H4·H2O + HN + HEH + HEHN + NH3 + AN + H2O → [NH3 + H2O] 留出液 +[N2H4 + HEHN + HN] 底部 The ammonia recovered from the distillate D2 can be recovered as a useful by - product or recycled as process fuel, and the hydrazine hydrate recovered from the distillate D2 can be recycled and used as raw material F1.

[0027] In a further example, the reaction in reactor 12 and distillation in distillation column 14 are carried out in series with the reaction in reactor 16 and distillation in distillation column 18 to provide a mixture of hydrazine hydrate, hydroxyethylhydrazine, and water of distillate D1 to be used as input to reactor 16. Instead, a premixed starting material of hydrazinium nitrate, hydroxyethylhydrazine, and optionally water is used as input to reactor 16. This divides the manufacturing process so that it essentially involves only the steps related to reactor 16 and distillation column 18.

[0028] It should be understood that additional process steps and intermediate distillation may be used between any of the steps disclosed herein to separate components not intended to be present in the final mixture M. The methods disclosed herein can be implemented as batch or continuous flow processes on a wide scale, from laboratory use to industrial production. It should also be understood that process parameters, such as the ratio of excess hydrazine hydrate to ethylene oxide, the type of distillation column, reflux ratio, operating temperature, operating pressure, and other parameters, may be modified to adjust process costs and / or efficiency, for example, in response to fluctuations in raw material and energy costs.

[0029] While the illustrated examples show combinations of features, it is not necessary to combine all of them to realize the advantages of the various embodiments of this disclosure. In other words, a system designed according to the embodiments of this disclosure does not necessarily include all of the features shown in any of the figures, or all of the parts schematically shown in the figures. Furthermore, selected features from one embodiment may be combined with selected features from another embodiment.

[0030] The above description is illustrative and not limiting in nature. It will be apparent to those skilled in the art that variations and modifications to the disclosed examples do not necessarily deviate from the present disclosure. The scope of legal protection granted in this disclosure can only be determined by considering the following claims.

Claims

1. A mixture of hydrazine hydrate and hydroxyethylhydrazine is reacted with a nitrate to produce a product mixture containing hydrazine hydrate, hydrazinium nitrate, hydroxyethylhydrazine, and hydroxyethylhydrazinium nitrate. The aforementioned mixture is distilled to produce a final mixture containing hydrazine, hydroxyethylhydrazinium nitrate, and hydrazinium nitrate. A method that includes the ability to do so.

2. The method according to claim 1, characterized in that the nitrate is selected from the group consisting of ammonium nitrate and nitric acid.

3. The method according to claim 1, characterized in that the nitrate contains ammonium nitrate.

4. The method according to claim 1, characterized in that the nitrate contains nitric acid.

5. The method according to claim 1, characterized in that the nitrate is ammonium nitrate.

6. The method according to claim 1, characterized in that the nitrate is nitric acid.

7. The method according to claim 1, characterized in that the mixture of hydrazine hydrate and hydroxyethyl hydrazine is produced by first reacting ethylene oxide with an excess of hydrazine hydrate to obtain an intermediate mixture containing hydrazine hydrate, hydroxyethyl hydrazine, and bis(hydroxyethyl)hydrazine.

8. The method according to claim 7, further comprising distilling the intermediate mixture to substantially remove the bis(hydroxyethyl)hydrazine from the intermediate mixture to obtain a mixture of the hydrazine hydrate and hydroxyethylhydrazine.

9. The method according to claim 1, characterized in that the molar composition of the final mixture is 50-75% hydrazine, 15-35% hydroxyethylhydrazinium nitrate, and 5-15% hydrazinium nitrate.

10. Ethylene oxide and excess hydrazine hydrate are reacted to produce an intermediate mixture containing hydrazine hydrate, hydroxyethyl hydrazine, and bis(hydroxyethyl)hydrazine, thereby producing a mixture of hydrazine hydrate and hydroxyethyl hydrazine. The intermediate mixture is distilled to substantially remove the bis(hydroxyethyl)hydrazine from the intermediate mixture to produce a mixture of hydrazine hydrate and hydroxyethylhydrazine. The mixture of hydrazine hydrate and hydroxyethylhydrazine is reacted with a nitrate to produce a product mixture containing hydrazine hydrate, hydrazinium nitrate, hydroxyethylhydrazine, and hydroxyethylhydrazinium nitrate. The aforementioned mixture is distilled to produce a final mixture containing hydrazine, hydroxyethylhydrazinium nitrate, and hydrazinium nitrate. A method that includes the ability to do so.

11. The method according to 10, characterized in that the nitrate is selected from the group consisting of ammonium nitrate and nitric acid.

12. The method according to 10, characterized in that the nitrate contains ammonium nitrate.

13. The method according to 10, characterized in that the nitrate contains nitric acid.

14. The method according to 10, characterized in that the nitrate is ammonium nitrate.

15. The method according to 10, characterized in that the nitrate is nitric acid.

16. The method according to 10, characterized in that the molar ratio of the excess hydrazine hydrate to the ethylene oxide is 2:1 to 9:1.

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