Difference between revisions of "Hydrazoic acid"

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| Name =Hydrazoic acid
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| IUPACName =Hydrogen azide
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| OtherNames = Azoimide<br>Hydrogen azide
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| Section1 = {{Chembox Identifiers
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| SMILES = [N-]=[N+]=[N@H]
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| Appearance = Colorless liquid
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| BoilingPtC = 37
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| Density = 1.09 g/cm<sup>3</sup>
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| Formula = HN<sub>3</sub>
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| MolarMass = 43.03 g/mol
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| MeltingPtC = -80
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| Odor = Intolerable pungent odor
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| pKa = 4.6 <ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, ISBN 0-07-049439-8</ref>
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| Solubility = Soluble
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| SolubleOther = Reacts with alkali, [[amine]]s<br>Soluble in [[alcohol]], [[ether]]s
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| DeltaHf = 300.25 kJ/mol
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| OtherCations = [[Sodium azide]]
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| OtherCompounds = [[Ammonia]]<br>[[Hydrazine]]<br>[[Triazane]]
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[[File:Hydrogen_azide_structure.png|thumb|290px]]
 
[[File:Hydrogen_azide_structure.png|thumb|290px]]
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'''Hydrazoic acid''', also known as '''hydrogen azide''' or '''azoimide''', is a colorless, volatile, and explosive liquid at room temperature and pressure, with the chemical formula HN<sub>3</sub>.
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'''Hydrazoic acid''', also known as '''hydrogen azide''' or '''azoimide''', is a colorless, volatile, and explosive liquid at room temperature and pressure, with the chemical formula '''HN<sub>3</sub>'''.
  
 
==Properties==
 
==Properties==
 
===Chemical===
 
===Chemical===
−
Hydrazoic acid is a weak acid, and will dissolve several metals, such as [[iron]], [[magnesium]], [[zinc]]. [[Antimony]] dissolves slowly in hydrogen azide.
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Hydrazoic acid is a mid-strength acid, it will dissolve many metals, such as [[iron]], [[copper]], [[aluminium]], [[magnesium]], [[zinc]]. [[Antimony]] dissolves slowly in hydrogen azide, as does [[silver]] at high concentrations. When mixed with [[hydrochloric acid]], it can attack [[gold]] and [[platinum]]. Platinum black will decompose hydrogen azide to ammonia and nitrogen.<ref>Robert Matyáš, Jiří Pachman, ''Primary Explosives'', 2013, Chapter 4 Azides</ref>
  
 
Dissolution in the strongest acids produces explosive salts containing the H<sub>2</sub>N=N=N<sup>+</sup> ion, for example:
 
Dissolution in the strongest acids produces explosive salts containing the H<sub>2</sub>N=N=N<sup>+</sup> ion, for example:
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===Physical===
 
===Physical===
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Hydrazoic acid is a colorless liquid, with a strong and toxic smell. It is very soluble in water, as well as alcohol and ether. Its density is 1.09 g/cm<sup>3</sup>. Anhydrous hydrozoic acid melts at −80 °C and boils at 37 °C. It is a weak acid (pK<sub>a</sub> = 4.75).
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Hydrazoic acid is a colorless liquid, with a strong and very unpleasant smell. It is very soluble in water, as well as alcohol and ether. Its density is 1.09 g/cm<sup>3</sup>. Anhydrous hydrozoic acid melts at −80 °C and boils at 37 °C. It is a mid-strength acid (pK<sub>a</sub> = 4.75), of approximately the same strength as [[formic acid]].
  
 
==Availability==
 
==Availability==
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==Projects==
 
==Projects==
 
*Synthesis of 2-Furonitrile
 
*Synthesis of 2-Furonitrile
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*[[Silver azide|Silver]], [[lead azide|lead]] and [[mercury azide]] preparation
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*[[Silver azide|Silver]], [[lead(II) azide|lead]] and [[mercury azide]] preparation
 
*Preparation of azides that hydrolyze in aqueous solutions, such as magnesium or antimony azide (should only be performed in aprotic solvents that do not react with hydrazoic acid, or with extremely small amounts of pure cold acid and metal or none at all)
 
*Preparation of azides that hydrolyze in aqueous solutions, such as magnesium or antimony azide (should only be performed in aprotic solvents that do not react with hydrazoic acid, or with extremely small amounts of pure cold acid and metal or none at all)
  
 
==Handling==
 
==Handling==
 
===Safety===
 
===Safety===
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Hydrazoic acid is volatile and highly toxic, similar in toxicity with cyanides, however it has no known antidote. It has a pungent smell and its vapors can cause strong headaches. In pure form it is prone to detonation, so it's best to work with diluted solutions. Azide salts carry the same dangers.
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Hydrazoic acid is volatile and highly toxic, similar in toxicity with cyanides, however it has no known antidote. It has a pungent smell and its vapors can cause strong headaches. In pure form it is prone to detonation, so it's best to work with diluted solutions. Azide salts carry the same dangers, and are prone to hydrolysis in aqueous solution.
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In case of hydrazoic acid poisoning, the patient should immediately leave the contaminated room (or be carried from there) and given access to outside air. In case of severe poisoning, the patient should immediately receive medical attention. If no medical attention is available, the patient should be given pure oxygen to breathe.  
  
 
===Storage===
 
===Storage===
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===Disposal===
 
===Disposal===
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Hydrazoic acid can be neutralized with an excess of sodium hydroxide. However, azide salts such as the sodium azide produced in this way are extremely toxic, and they should NEVER be disposed of as is, especially not down the drain. Sodium azide produced this way should either be destroyed with [[nitrous acid]], crystallized out by evaporation and carefully heated to decomposition outside, or precipitated as a transition metal azide. Many transition metal azides are explosive, and these too must be very carefully disposed of.
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Hydrazoic acid can be neutralized with an excess of sodium hydroxide. However, azide salts such as the sodium azide produced in this way are extremely toxic, and they should NEVER be disposed of as is, especially not down the drain. Sodium azide produced this way should either be destroyed with [[nitrous acid]], crystallized out by evaporation and carefully heated to decomposition outside, or precipitated as a transition metal azide. Many transition metal azides are explosive or will hydrolyze, and these too must be very carefully disposed of.
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Bleach (dil. sodium hypochlorite) can also be used.<ref>https://www.ncbi.nlm.nih.gov/m/pubmed/20667654/</ref>
  
 
==References==
 
==References==
 
<references/>
 
<references/>
−
 
 
===Relevant Sciencemadness threads===
 
===Relevant Sciencemadness threads===
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=1987 Azides]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=1987 Azides]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=27640 The true mad science, hydrogen azide distillation]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=27640 The true mad science, hydrogen azide distillation]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=156715 Has anyone smelled hydrazoic acid?How does it smell like?Is it worse than chlorine,ozone and nitrogen dioxide?]
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[[Category:Chemical compounds]]
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[[Category:Inorganic compounds]]
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[[Category:Hydrogen compounds]]
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[[Category:Nitrogen compounds]]
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[[Category:Acids]]
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[[Category:Mid-strength acids]]
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[[Category:Mineral acids]]
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[[Category:Azides]]
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[[Category:Energetic materials]]
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[[Category:Things that can kill you very quickly]]
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[[Category:Blood agents]]
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[[Category:Liquids]]

Latest revision as of 22:42, 13 February 2021

Hydrazoic acid
Names
IUPAC name
Hydrogen azide
Other names
Azoimide
Hydrogen azide
Identifiers
Jmol-3D images Image
Properties
HN3
Molar mass 43.03 g/mol
Appearance Colorless liquid
Odor Intolerable pungent odor
Density 1.09 g/cm3
Melting point −80 °C (−112 °F; 193 K)
Boiling point 37 °C (99 °F; 310 K)
Soluble
Solubility Reacts with alkali, amines
Soluble in alcohol, ethers
Acidity (pKa) 4.6 [1]
Thermochemistry
300.25 kJ/mol
Hazards
Safety data sheet Guidechem
Related compounds
Related compounds
 Ammonia
Hydrazine
Triazane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references
Hydrogen azide structure.png

Hydrazoic acid, also known as hydrogen azide or azoimide, is a colorless, volatile, and explosive liquid at room temperature and pressure, with the chemical formula HN3.

Properties

Chemical

Hydrazoic acid is a mid-strength acid, it will dissolve many metals, such as iron, copper, aluminium, magnesium, zinc. Antimony dissolves slowly in hydrogen azide, as does silver at high concentrations. When mixed with hydrochloric acid, it can attack gold and platinum. Platinum black will decompose hydrogen azide to ammonia and nitrogen.[2]

Dissolution in the strongest acids produces explosive salts containing the H2N=N=N+ ion, for example:

HN=N=N + HSbCl6 → [H2N=N=N+] + [SbCl6]−

Hydrazoic acid decomposes to nitrogen and hydrogen:

2HN3 → H2 + 3N2

Physical

Hydrazoic acid is a colorless liquid, with a strong and very unpleasant smell. It is very soluble in water, as well as alcohol and ether. Its density is 1.09 g/cm3. Anhydrous hydrozoic acid melts at −80 °C and boils at 37 °C. It is a mid-strength acid (pKa = 4.75), of approximately the same strength as formic acid.

Availability

Due to its long list of hazards, hydrazoic acid is not sold, and has to be prepared in the laboratory.

Preparation

Hydrazoic acid can be prepared by reacting a strong acid, such as sulfuric acid, with an azide, such as sodium azide or barium azide. The latter is preferred as the insoluble barium sulfate produced can simply be filtered out, giving a clean solution of hydrogen azide. It's recommended to produce diluted acid, as pure hydrazoic acid is prone to detonation.

Hydrazoic acid was originally prepared by the reaction of hydrazine with nitrous acid:

N2H4+ HNO2 → HN3 + 2 H2O

As nitrous acid is already diluted, this reaction is safer. It can similarly be accomplished using nitric acid or concentrated hydrogen peroxide.

Projects

  • Synthesis of 2-Furonitrile
  • Silver, lead and mercury azide preparation
  • Preparation of azides that hydrolyze in aqueous solutions, such as magnesium or antimony azide (should only be performed in aprotic solvents that do not react with hydrazoic acid, or with extremely small amounts of pure cold acid and metal or none at all)

Handling

Safety

Hydrazoic acid is volatile and highly toxic, similar in toxicity with cyanides, however it has no known antidote. It has a pungent smell and its vapors can cause strong headaches. In pure form it is prone to detonation, so it's best to work with diluted solutions. Azide salts carry the same dangers, and are prone to hydrolysis in aqueous solution.

In case of hydrazoic acid poisoning, the patient should immediately leave the contaminated room (or be carried from there) and given access to outside air. In case of severe poisoning, the patient should immediately receive medical attention. If no medical attention is available, the patient should be given pure oxygen to breathe.

Storage

Hydrazoic acid should only be stored as diluted solutions, is closed bottles, in well ventilated areas or in a special storage cabinet. Should not be stored for long periods of time.

Disposal

Hydrazoic acid can be neutralized with an excess of sodium hydroxide. However, azide salts such as the sodium azide produced in this way are extremely toxic, and they should NEVER be disposed of as is, especially not down the drain. Sodium azide produced this way should either be destroyed with nitrous acid, crystallized out by evaporation and carefully heated to decomposition outside, or precipitated as a transition metal azide. Many transition metal azides are explosive or will hydrolyze, and these too must be very carefully disposed of.

Bleach (dil. sodium hypochlorite) can also be used.[3]

References

  1. ↑ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
  2. ↑ Robert Matyáš, Jiří Pachman, Primary Explosives, 2013, Chapter 4 Azides
  3. ↑ https://www.ncbi.nlm.nih.gov/m/pubmed/20667654/

Relevant Sciencemadness threads

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