Hydrazine

Lead Author

Sara Worsham
Lead Editor: Steven G. Gilbert

Chemical and Physical Properties of Hydrazine


Hydrazine is a colorless, oily liquid or sometimes white crystalline compound (Hydrazine 2000; Environmental Protection Agency (EPA) 2008; Material Safety Data Sheet (MSDS) 2005). This compound is a very highly reactive base and reducing agent, having many industrial as well as military uses. The chemical structure of hydrazine is simple as illustrated below:

Figure 1: Chemical structure of Hydrazine (N2H4). Note that there are two pairs of lone electrons resulting in this highly reactive compound.

Image created by author of this wikipage.

Some chemical and physical characteristics of Hydrazine (Hydrazine 2000; EPA 2008; MSDS 2005; Safety Data for Hydrazine 2008):

  • Molecular Formula N2H4
  • Hydrazine Synonyms: diamine, nitrogen hydride, levoxine, oxytreat 35
  • Physical State and Appearance: Liquid
  • Molecular weight: 32.05 g mol^-1^
  • Boiling point: 113.5oC (236.3oF)
  • Melting point: 1.4oC (34.5oF )
  • Specific gravity: 1 (Water = 1)
  • Vapor pressure: 10 mm of Hg (20oC)
  • Solubility: Easily soluble in cold water, hot water.
  • Odor threshold: 3.7 ppm

Hydrazine is also flammable in the presence of open flames, sparks, heat, and oxidizing materials (MSDS 2005). Hydrazine is highly explosive in the presence of oxidizing materials and metals and incompatible with moisture and acids (MSDS 2005).
 

Uses


Hydrazine can be used in nickel plating, the removal of halogens from wastewaters, as an inhibitor to corrosion, and in photograph development (Hydrazine, 2000; Choudhary et. al 1997; EPA 2008). It has also been used in boiler water treatment, in blowing agent manufacturing for producing plastics used in vinyl flooring and auto foam cushions, in the production of agricultural chemicals such as maleic hydrazide, as a reducing agent in nuclear fuel reprocessing, and even used for medicinal purposes as a medication for sickle cell and cancer (Choudhary et. al 1997; Lunn et. al 1983; EPA, 2008). Some nitrogen fixing bacteria may create hydrazine as a by-product while some derivatives (N-methyl-N-formylhydrazine and agaritine) have been obtained from edible mushrooms (Lunn et. al 1983). Despite these few natural occurrences, hydrazine is primarily manufactured. Hydrazine is also contained in tobacco and cigarette smoke (Liu et. al 1974; EPA 2008). According to Liu et. al, Hydrazine is contained in tobacco smoke in the form of pentafluorobenzaldehyde (1974).

Current Events


Recently, hydrazine has gained attention after the Navy announced it may attempt to shoot down a government spy-satellite containing the chemical as a fuel source and rocket propellant.

Routes of Exposure


  • Eye and skin contact
  • Inhalation
  • Ingestion

(Choudhary et al. 1997; EPA 2008; MSDS 2005; OSHA 2008).

Derivatives of Hydrazine



Figure: The many derivative of Hydrazine. Image taken from Novasep.com Hazardous Chemistry: Hydrazine Chemistry.

The class of hydrazines refers to three chemically similar compounds including: hydrazine (N2H4), 1,1-dimethylhydrazine (CH8N), and 1,2-dimethylhydrazine (C2H8N2) (Choudhary et. al 1997). Hydrazines are thought to be a human carcinogen with immediately dangerous levels of exposure being 50ppb (Occupational Safety & Health Administration (OSHA) 2008; EPA 2008). Hydrazines are very volatile liquids, so the risk of exposure through inhalation is of great concern. Studies show that while these compounds are similar, the toxicity of 1,1-dimethylhydrazine vapors is the greatest; 1,2-dimethylhydrazine vapors the least toxic (Choudhary et. al 1997).

Metabolism


Adapted from Choudhary et al. 1997.

There are several pathways involved with the metabolism of Hydrazines including both enzymatic and nonenzymatic. People with slow acetylation may accumulate more of the compound due to the decreased ability to metabolize the hydrazine. The route of exposure, while it does play an small role in the metabolism, ultimately is inconsequential with the formation of metabolites.

Using animal studies, it has been shown that hydrazine is metabolized in the liver. This metabolism is increased with an introduction of cytochrome P-450 inducers and was decreased by P-450 inhibitors. Free radicals were produced when hydrazine was metabolized including acetyl, hydroxyl, and hydrogen radicals. The occurrence of an acetyl radical indicates that acetylation of hydrazine occurs before radical formation. Data taken from this animal study indicates that hydrazine is metabolized by P-450 but may be transformed through other pathways as well. The formation of the free radicals during metabolism potentially play a part in the toxicity of hydrazine.

Health Effects of Hydrazine Exposure

This substance is toxic to blood, kidneys, lungs, the nervous system and mucous membranes (MSDS 2005). Liquid and spray contact can produce tissue damage to mucous membranes particularly the eyes, nose, mouth, and respiratory tract (MSDS 2005). Skin contact may produce burns and inhalation of spray may produce irritation of the respiratory tract with repeated or prolonged exposures producing target organ damage (MSDS 2005). Severe over-exposure can result in death (MSDS 2005).

Acute respiratory exposure to hydrazines can result in dyspnea and pulmonary edema, pneumonia, tracheitis, and bronchitis (Choudhary et. al 1997). Animal studies have shown that chronic exposure can lead to alveolar hemorrhage, emphysema, and atelectasis; This data indicates that hydrazine and l,l-dimethylhydrazine can produce lung damage (Choudhary et. al 1997).

According to OSHA and the EPA, potential symptoms of hydrazine exposure include: Eye, nose and throat irritation, temporary blindness, dizziness, nausea, dermatitis, skin and eye burns, malar (cheek) rash, photosensitivity, antinuclear antibody, antibody to nDNA and coma for only one case. In animals, symptoms range from bronchitis and pulmonary edema to liver and kidney damage and even convulsions (2008). Hydrazine may also be detectable in the blood of an exposed individual (EPA 2008).

Protective Measures When Using Hydrazine


Taken from Hydrazine MSDS (2005)

Individuals working with Hydrazine should wear the following protective equipment:

  • Gloves
  • Full Suit
  • Approved/certified Vapor Respirator
  • Face Shield
  • Boots

Ecological Concerns


Due to the extreme corrosive potential of this chemical and its reactivity with moisture and oxidants, Hydrazine in the environment is of great concern. While the ecotoxicity is not known, the products of biodegradation of Hydrazine are more toxic than the parent compound. Potentially hazardous short and long term degradation products are to be expected (MSDS 2005).

Case Study of Hydrazine Poisoning


In a 1965 correspondence from F. James Reid to the British Medical Journal, the effects of accidental hydrazine ingestion can be seen.

A young English sailor had been drinking beer during the afternoon before being placed on duty in the evening. He was considered to be fit for duty and competent until the accident. While working in his ship's engine room, the young sailor ingestion between a mouthful and a cupful of concentrated Hydrazine believing it was water.

  • Hydrazine, greatly diluted, was used on board the ship to prevent corrosion in the ship's boilers by seawater.

Immediately upon drinking the chemical, the sailor vomited and returned to the deck to report to his superior officer at 11:30pm. After having been given a raw egg and milk, he vomited once more and collapsed, unconscious onto the floor.

Upon admission in a West African Hospital at midnight he was flushed, afebrile, unconscious, continent, and vomiting. His pupils were dilated, central and reacted to light; however, there were no chemical burns on his lips or mouth and he was able to swallow. At this time the respiratory and central nervous systems were normal upon clinical examination.

In response to the accident, the stomach was washed out with warm water which was partially siphoned and vomited back. He was given intramuscular chloroquine sulphate due to the prevalence of malaria in the region; cyanocobalamin, because the chemical was believed to have a cyanide-like effect; and ascorbic acid all intravenously with dextrose, dextrose-saline, and Hartmann's solution. These chemicals were given in all three liters over a period of 16 hours. The patient then passed 600ml of alkaline urine via a catheter, with the condition of his bladder at that time remaining unknown.

Twelve hours after the ingestion of the hydrazine, his condition remained unchanged with the exception that vomiting had ceased and the pupils were smaller and divergent to the right. Two episodes of violence requiring restraint by four strong African nurses also occurred.

Sixteen hours after ingestion, the patient was more flaccid and once again violent; it was decided to send him to the U.K. by air. 33 hours after the accident, the patient was flown out; however, once reaching France, the pilot of the aircraft refused to accept responsibility of the patient as his respiration became irregular and shallow.

48 hours after the accident the patient was admitted to a Paris hospital. His condition upon arrival was described as comatose and convulsive. He was intubated under anesthesia and given mechanically assisted respiration for the next ten hours; he was also given 10% dextrose and vitamin B.

The patient improved hour by hour, though the main concern was for his neurological state. His psyche, memory, voluntary motor skills, and higher functions were normal. However, he had ataxia even with his eyes open, a lateral nystagmus to the right, and a loss of vibration sense. He was unable to write, though he could draw. There was paresthesia of all four limbs at the extremities and he was unable to reproduce one hand movement imposed upon the other. Severe hypoesthesia of the hand (especially the right hand), in distribution of the radial nerve ensued. E.E.G. results were within normal limits and tendon reflexes were normal. Fortunately, the ataxia was improving to the point that the sailor would able to travel unescorted by air to England, only two weeks after leaving Africa.

  • The final condition of the young man is not known.

References


1) Choudhary G, IIansen H, Donkin S, Kirman C. 1997. Toxicological Profile for Hydrazines. US Department of Health and Human Services Public Health Service Agency for Toxic Substances and Disease Registry (ATSDR). Atlanta, GA: 1-224.

2) Hydrazine. Chronic Toxicity Summary. Determination of Noncancer Chronic Reference Exposure Levels. Batch 2A. December 2000. A - 137-142.

3) Liu YY, Schmeltz I, Hoffman D. 1974. Chemical studies on tobacco smoke. Quantitative analysis of hydrazine in tobacco and cigarette smoke. Anal Chem 46:885-889.

4) Lunn G, Sansone EB, Keefer LK. 1983. Reductive destruction of hydrazines as an approach to hazard control. Environ Sci. Technol. 17:240-243.

5) Material Safety Data Sheet (MSDS). Hydrazine MSDS. (2005, October 09). ScienceLab.com, Inc. Chemicals and Laboratory Equipment. Houston, TX: 1-7.

6) Mount M. (2008, February 15). Officials: U.S. to try to shoot down errant satellite. Cable News Network (CNN).

7) Reid, JF (1965, November 20). Hydrazine Poisoning. General Hospital, Jersey, Channel Islands. Correspondence. British Medical Journal: 1246.

8) Safety Data for Hydrazine (anhydrous). (2008, February 25). Physical & Theoretical Chemistry Lab (PTCL). Available: http://msds.chem.ox.ac.uk/HY/hydrazine.html (Accessed 25 March 2008).

9) U.S. Environmental Protection Agency (EPA). Technology Transfer Network Air Toxics Web Site. Available: http://www.epa.gov/ttn/atw/hlthef/hydrazin.html (Accessed 02 March 2008).

10) US Department of Labor Occupational Safety & Health Administration (OSHA). Available: http://www.osha.gov/dts/chemicalsampling/data/CH_245900.html (Accessed 02 March 2008).

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