General
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|---|---|
| Name | Hydrazine |
| Chemical formula | N2H4 |
| Appearance | Colourless liquid |
Physical
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| Formula weight | 32.0 amu |
| Melting point | 274 K (1 °C) |
| Boiling point | 387 K (114 °C) |
| Density | 1.0 ×103 kg/m3 |
| Solubility | very soluble |
Thermochemistry
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| ΔfH0gas | 95.35 kJ/mol |
| ΔfH0liquid | 50.63 kJ/mol |
| ΔfH0solid | 37.63 kJ/mol |
| S0gas, 1 bar | 238.66 J/mol·K |
| S0liquid, 1 bar | 121.52 J/mol·K |
| S0solid | ? J/mol·K |
Safety
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| Ingestion | Toxic, possibly carcinogenic |
| Inhalation | Very dangerous—extremely destructive to the upper respiratory tract |
| Skin | Can cause severe burns, can be absorbed into bloodstream |
| Eyes | Can cause permanent damage |
| More info | Hazardous Chemical Database |
| SI units were used where possible. Unless otherwise stated, standard conditions were used. | |
It has an oxidation number of -2. It is a liquid with weak basic properties similar to ammonia. Due to the alpha effect the nucleophilicity is much stronger than that of ammonia, which makes it more reactive. It can be made by oxidizing ammonia with sodium hypochlorite (the Raschig process). It is a monopropellant rocket fuel.
Hydrazine derivatives 1,1-dimethylhydrazine and 1,2-dimethylhydrazine, in which two of the hydrogen atoms are substituted with methyl groups, are also described as hydrazines.
The asymmetric dimethylhydrazine is used to make hypergolic (self-igniting) bipropellant rocket fuels.
Breathing hydrazines for short periods may cause coughing and irritation of the throat and lungs, convulsions, tremors, or seizures. Breathing hydrazines for long periods may cause liver and kidney damage, as well as serious effects on reproductive organs.
Eating or drinking small amounts of hydrazines may cause nausea, vomiting, uncontrolled shaking, inflammation of the nerves, drowsiness, or coma.
Tumors have been seen in many organs of animals that were exposed to hydrazines by ingestion or breathing, but most tumors have been found in the lungs, blood vessels, or colon. 1,2-Dimethylhydrazine has caused colon cancer in laboratory animals following a single exposure.
The Department of Health and Human Services (DHHS) has determined that hydrazine and 1,1-dimethylhydrazine are known carcinogens. The International Agency for Research on Cancer (IARC) has determined that hydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine are possible human carcinogens. The EPA has determined that hydrazine, 1,1-dimethylhydrazine, and 1,2-dimethylhydrazine are probable human carcinogens.
The American Conference of Governmental Industrial Hygienists (ACGIH) currently lists hydrazine and 1,1-dimethylhydrazine as suspected carcinogens, but has recently recommended that the listing of hydrazine be changed to that of animal carcinogen, not likely to cause cancer to people under normal exposure conditions.Health effects