Hydrazine

Hydrazine

Anhydrous hydrazine stored in a glass ampoule.
Names
IUPAC name Hydrazine
Systematic IUPAC name Hydrazine
Other names Diamine Diazane Tetrahydridodinitrogen(N—N)
Properties
Chemical formula	N2H4
Molar mass	32.0452
Appearance	Clear liquid
Odor	Ammonia-like
Density	1.014 g/cm3 (15 °C)
Melting point	2 °C (36 °F; 275 K)
Boiling point	114 °C (237 °F; 387 K)
Solubility in water	Miscible
Solubility	Reacts with acids, halogens, hydrogen peroxide Soluble in methanol, ethanol, propanol, isobutanol and amyl alcohol
Vapor pressure	1 kP (at 30.7 °C)
Acidity (pKa)	8.10
Thermochemistry
Std molar entropy (So298)	121.52 J·K−1·mol−1
Std enthalpy of formation (ΔfHo298)	50.63 kJ/mol
Hazards
Safety data sheet	Sigma-Aldrich
Flash point	52 °C (125.6 °F; 325 K)
Lethal dose or concentration (LD, LC):
LD50 (Median dose)	59–60 mg/kg (oral in rats, mice)
LC50 (Median concentration)	260 ppm (rat, 4 hr) 630 ppm (rat, 1 hr) 570 ppm (rat, 4 hr) 252 ppm (mouse, 4 hr)
Related compounds
Related compounds	Ammonia Triazane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Hydrazine is an inorganic compound with the chemical formula N₂H₄ or H₂N-NH₂. It is a toxic compound used as rocket fuel.

Properties

Chemical

Hydrazine, like ammonia, will form salts with acids. With sulfuric acid, for example, forms hydrazine sulfate.

N₂H₄ + H₂SO₄ → N₂H₅HSO₄

Hydrazine ignites in contact with various oxidizers, like liq. ozone, liq. chlorine, chromyl chloride, dinitrogen tetroxide/nitrogen dioxide, conc. hydrogen peroxide, cobalt(III) fluoride, vanadium oxytrichloride . Reaction of anhydrous hydrazine with osmium tetroxide is extremely violent, basically an explosion. Reaction with elemental bromine or iodine however, while violent, it does not lead to ignition.

Anhydrous hydrazine will rapidly and violently reduce iodine pentoxide to hydrogen iodide. Any elemental iodine produced is immediately reduced to HI. The reaction also produces side products like hydrogen, nitrogen, ammonia and copious amounts of ammonium iodide fumes. The reaction can sometimes be violent enough that it may cause an explosion.

Hydrazine reacts with sodium nitrite forming sodium azide:

N₂H₄ + NaNO₂ → NaN₃ + 2 H₂O

Physical

Hydrazine is a clear fuming oily liquid, with a toxic strong ammonia like odor. It is miscible with water, and soluble in several solvents, like methanol or ethanol. Hydrazine boils at 114 °C and melts at 2 °C.

Availability

Anhydrous hydrazine is sold by chemical suppliers, though it's not easily available to the amateur chemist due to its hazards.

Preparation

Anhydrous hydrazine can be made by reacting hydrazine sulfate with a strong base, filter the reaction product and drying the resulting condensate. Avoid distilling the resulting hydrazine at atmospheric conditions and pressure, as it may explode. Distillation can be done in an inert atmosphere, but any trace of air may lead to an explosion.

Projects

• Make hydrazine sulfate
• Make sodium azide
• Make hydrazoic acid (DANGEROUS!)
• Make nickel hydrazine nitrate
• Reducing agent
• Rocket fuel

Handling

Safety

Free hydrazine is extremely toxic and should only be handled with proper protection. It will slowly decompose to release nitrogen and ammonia. As a solution is less dangerous, though it's fumes are still very toxic. It may explode during its distillation in the presence of oxygen, due to its low autoignition point, so it's best to perform the distillation in an oxygen-free environment.

Due to these risks, the safest way to handle hydrazine is in the sulfate form.

Storage

While it can be stored in sealed or closed containers, the best and safest way to store hydrazine is in salt form, most often as the sulfate form. It can be easily liberated from this form with an alkali when or if needed.

Hydrazine will slowly leach silica from glass, so avoid storing it in glass containers. Type 304L and 347 stainless steel containers are generally used for storing hydrazine, though high density polyethylene is also suitable.

Disposal

Hydrazine can be neutralized with a diluted solution of calcium hypochlorite or another oxidizer. Avoid using strong or concentrated oxidizers, like conc. hydrogen peroxide, as this will result in a steam explosion.

References

Relevant Sciencemadness threads

• Hydrazine
• Making Hydrazine