Hydrazine hydrate
[CAS# 7803-57-8]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Hydrazine and hydroxylamine and their inorganic salts
• Name: Hydrazine hydrate
• Molecular Formula: H₄N₂.H₂O
• Molecular Weight: 50.06
• CAS Registry Number: 7803-57-8 (10217-52-4)
• EC Number: 600-285-7
• SMILES: NN.O

Properties

• Density: 1.032g/mL (20 °C) (Expl.)
• Melting point: -51.5 °C (Expl.)
• Boiling point: 120.1 °C (Expl.)
• Refractive index: 1.4285-1.4315 (Expl.)
• Flash point: 75 °C (Expl.)

Safety Data

• Hazard Symbols: GHS03;GHS05;GHS06;GHS07;GHS08;GHS09 Danger
• Risk Statements: H226-H300-H301+H311+H331-H301-H311-H314-H317-H330-H331-H350-H400-H410
• Safety Statements: P203-P210-P233-P240-P241-P242-P243-P260-P261-P264-P270-P271-P272-P273-P280-P284-P301+P316-P301+P330+P331-P302+P352-P302+P361+P354-P303+P361+P353-P304+P340-P305+P354+P338-P316-P318-P320-P321-P330-P333+P313-P361+P364-P362+P364-P363-P370+P378-P391-P403+P233-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Skin corrosion	Skin Corr.	1B	H314
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Acute toxicity	Acute Tox.	3	H301
Carcinogenicity	Carc.	1B	H350
Flammable liquids	Flam. Liq.	3	H226
Skin sensitization	Skin Sens.	1	H317
Acute toxicity	Acute Tox.	3	H311
Acute toxicity	Acute Tox.	3	H331
Serious eye damage	Eye Dam.	1	H318
Acute toxicity	Acute Tox.	2	H330
Specific target organ toxicity - repeated exposure	STOT RE	1	H372
Acute toxicity	Acute Tox.	2	H310
Specific target organ toxicity - single exposure	STOT SE	1	H370
Skin sensitization	Skin Sens.	1A	H317
Germ cell mutagenicity	Muta.	2	H341
Reproductive toxicity	Repr.	2	H361
Acute toxicity	Acute Tox.	2	H300
Germ cell mutagenicity	Muta.	1B	H340
Carcinogenicity	Carc.	2	H350

• Transport Information: UN 2029; UN 2030

Discovery and Applications

Hydrazine hydrate, with the chemical formula N2H4·H2O, is an aqueous solution of hydrazine, a highly reactive and versatile compound. Hydrazine was first synthesized in 1887 by the German chemist Theodor Curtius, who discovered it through the reduction of diazomethane. Since its discovery, hydrazine has been the subject of intense research and has found applications in various industries, from rocket propellants to pharmaceuticals.

Hydrazine hydrate is most commonly used as a precursor in the synthesis of various hydrazine-based compounds, including agricultural chemicals, pharmaceuticals, and industrial products. It is widely used in the production of blowing agents for foamed plastics, especially in the production of polyurethane foams. In this context, hydrazine hydrate undergoes chemical reactions to release gas, which expands the plastic material and gives it a lightweight and insulated structure. This makes it a critical component in the manufacture of products such as thermal insulations, seat cushions, and construction materials.

One of the most well-known and significant applications of hydrazine hydrate is in the aerospace industry. Hydrazine is a key component in the formulation of rocket propellants. It is used as a fuel in monopropellant rocket engines, where it decomposes into nitrogen gas and hydrogen gas in the presence of a catalyst, releasing a large amount of energy. Hydrazine-based propellants have been essential for spacecraft propulsion, satellite thrusters, and space exploration missions. Its high energy density and storability make hydrazine a preferred choice in space technologies, even though the compound is highly toxic and requires careful handling.

In addition to its use in propulsion systems, hydrazine hydrate is involved in various chemical processes. It serves as a reducing agent in the synthesis of pharmaceuticals and specialty chemicals. Hydrazine hydrate is often used in the reduction of certain organic compounds, which can lead to the production of useful chemicals such as hydrazones, azines, and other nitrogen-containing derivatives. These compounds have applications in areas such as dye manufacturing, polymer chemistry, and even food processing.

Hydrazine hydrate also plays an important role in water treatment. It is used as an oxygen scavenger in boiler systems, where it reacts with dissolved oxygen to prevent corrosion. By removing oxygen from water, hydrazine helps in maintaining the integrity of the metal surfaces of pipes and boilers. This application is critical in industries such as power generation, where maintaining the efficiency and longevity of machinery is crucial.

Despite its many applications, hydrazine hydrate is highly toxic and poses significant health and environmental risks. It is a known carcinogen, and exposure to hydrazine can cause serious health effects, including damage to the liver, kidneys, and nervous system. Therefore, strict safety protocols are necessary when handling this compound, particularly in industrial and laboratory environments. Additionally, efforts are being made to develop safer and more environmentally friendly alternatives to hydrazine-based propellants and other applications.

In conclusion, hydrazine hydrate is a vital chemical compound with a range of industrial and scientific applications. Its role in the aerospace industry, as a reducing agent in chemical synthesis, and as an oxygen scavenger in water treatment underscores its versatility. However, due to its toxicity and potential hazards, the use of hydrazine hydrate must be approached with caution and responsibility.

References

2008. Base-Mediated Conversion of Hydrazine to Diazene and Dinitrogen at an Iron Center. Inorganic Chemistry, 47(23).
DOI: 10.1021/ic801856q

2012. Ultraviolet-Visible Light (UV-Vis)-Reversible but Fluorescence-Irreversible Chemosensor for Copper in Water and Its Application in Living Cells. Analytical Chemistry, 84(4).
DOI: 10.1021/ac202734m

2013. Liquid crystal self-templating approach to ultrastrong and tough biomimic composites. Scientific Reports, 3.
DOI: 10.1038/srep02374