Hydroxylamine

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"Aminol" redirects here. Not to be confused with hemiaminal.
Hydroxylamine
Stereo, skeletal formula of hydroxylamine with all explicit hydrogens added
Stereo, skeletal formula of hydroxylamine with all explicit hydrogens added
Ball-and-stick model of hydroxylamine
Ball-and-stick model of hydroxylamine
Stereo, skeletal formula of hydroxylamine with all explicit hydrogens added and assorted dimensions
Names
IUPAC name
Azinous acid
Preferred IUPAC name
Hydroxylamine (only preselected[1])
Other names
  • Aminol
  • Azanol
  • Hydroxyammonia
  • Hydroxyamine
  • Hydroxyazane
  • Hydroxylazane
  • Nitrinous acid
Identifiers
3D model (
JSmol
)
3DMet
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard
 100.029.327 Edit this at Wikidata
EC Number
  • 232-259-2
478
KEGG
MeSH Hydroxylamine
RTECS number
  • NC2975000
UNII
  • InChI=1S/H3NO/c1-2/h2H,1H2 checkY
    Key: AVXURJPOCDRRFD-UHFFFAOYSA-N checkY
  • InChI=1/H3NO/c1-2/h2H,1H2
    Key: AVXURJPOCDRRFD-UHFFFAOYAD
  • NO
Properties
NH2OH
Molar mass 33.030 g·mol−1
Appearance Vivid white, opaque crystals
Density 1.21 g cm−3 (at 20 °C)[2]
Melting point 33 °C (91 °F; 306 K)
Boiling point 58 °C (136 °F; 331 K) /22 mm Hg (decomposes)
Soluble
log P −0.758
Acidity (pKa) 6.03 ([NH3OH]+)
Basicity (pKb) 7.97
Structure
Tricoordinated at N, dicoordinated at O
Trigonal pyramidal at N, bent
at O
0.67553 D
Thermochemistry
46.47 J/(K·mol)
236.18 J/(K·mol)
Std enthalpy of
formation
(ΔfH⦵298)
 −39.9 kJ/mol
Hazards
GHS labelling:
GHS01: ExplosiveGHS05: CorrosiveGHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Danger
H200, H290, H302, H312, H315, H317, H318, H335, H351, H373, H400
P201, P202, P234, P260, P261, P264, P270, P271, P272, P273, P280, P281, P301+P312, P302+P352, P304+P340, P305+P351+P338, P308+P313, P310, P312, P314, P321, P322, P330, P332+P313, P333+P313, P362, P363, P372, P373, P380, P390, P391, P401, P403+P233, P404, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g. hydrogen peroxideSpecial hazards (white): no code
2
1
3
Flash point 129 °C (264 °F; 402 K)
265 °C (509 °F; 538 K)
Lethal dose or concentration (LD, LC):
408 mg/kg (oral, mouse); 59–70 mg/kg (intraperitoneal mouse, rat); 29 mg/kg (subcutaneous, rat)[3]
Safety data sheet (SDS) ICSC 0661
Related compounds
Related hydroxylammonium salts
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Hydroxylamine (also known as hydroxyammonia) is an

Nylon-6. The oxidation of NH3 to hydroxylamine is a step in biological nitrification.[5]

History

Hydroxylamine was first prepared as hydroxylammonium chloride in 1865 by the German chemist Wilhelm Clemens Lossen (1838-1906); he reacted tin and hydrochloric acid in the presence of ethyl nitrate.[6] It was first prepared in pure form in 1891 by the Dutch chemist Lobry de Bruyn and by the French chemist Léon Maurice Crismer (1858-1944).[7][8] The coordination complex ZnCl2(NH2OH)2 (zinc dichloride di(hydroxylamine)), known as Crismer's salt, releases hydroxylamine upon heating.[9]

Production

Hydroxylamine or its

cations [NH3OH]+) can be produced via several routes but only two are commercially viable. It is also produced naturally as discussed in a section on biochemistry
.

From nitric oxide

NH2OH is mainly produced as its

catalysts in the presence of sulfuric acid.[10]

2 NO + 3 H2 + 2 H2SO4 → 2 [NH3OH]+[HSO4]−

Raschig process

Another route to NH2OH is the

anion
:

[NH4]+[NO2]− + 2 SO2 + NH3 + H2O → 2 [NH4]+ + N(OH)(SO−3)2

This anion is then

hydrolyzed to give hydroxylammonium sulfate
[NH3OH]2SO4:

N(OH)(SO−3)2 + H2O → NH(OH)(SO−3) + HSO−4
2 NH(OH)(SO−3) + 2 H2O → [NH3OH]2SO4 + SO2−4

Solid NH2OH can be collected by treatment with

liquid ammonia. Ammonium sulfate, [NH4]2SO4, a side-product insoluble in liquid ammonia, is removed by filtration; the liquid ammonia is evaporated to give the desired product.[4]
The net reaction is:

2 NO−2 + 4 SO2 + 6 H2O + 6 NH3 → 4 SO2−4 + 6 [NH4]+ + 2 NH2OH

A base then frees the hydroxylamine from the salt:

[NH3OH]Cl + NaOCH2CH2CH2CH3 → NH2OH + NaCl + CH3CH2CH2CH2OH[4]

Other methods

electrolytic reduction of nitric acid with HCl or H2SO4 respectively:[11][12]

HNO3 + 3 H2 → NH2OH + 2 H2O

Hydroxylamine can also be produced by the reduction of nitrous acid or potassium nitrite with bisulfite:

HNO2 + 2 HSO−3 → N(OH)(OSO−2)2 + H2O → NH(OH)(OSO−2) + HSO−4
NH(OH)(OSO−2) + [H3O]+ → [NH3OH]+ + HSO−4 (100 °C, 1 h)

hydroxylamine hydrochloride and carbon monoxide via the hydroxamic acid.[citation needed
]

A direct production of hydroxylamine from molecular nitrogen is also possible in water plasma.[13]

Reactions

Hydroxylamine reacts with

alkylating agents, which can attach to either the oxygen or the nitrogen
atoms:

R−X + NH2OH → R−O−NH2 + HX
R−X + NH2OH → R−NH−OH + HX

The reaction of NH2OH with an aldehyde or ketone produces an oxime.

R2C=O + [NH3OH]Cl → R2C=N−OH + NaCl + H2O (in NaOH solution)

This reaction is useful in the purification of ketones and aldehydes: if hydroxylamine is added to an aldehyde or ketone in solution, an oxime forms, which generally precipitates from solution; heating the precipitate with an inorganic acid then restores the original aldehyde or ketone.[14]

Oximes such as dimethylglyoxime are also employed as ligands.

NH2OH reacts with

chlorosulfonic acid to give hydroxylamine-O-sulfonic acid:[15]

HO−S(=O)2−Cl + NH2OH → NH2−O−S(=O)2−OH + HCl

When heated, hydroxylamine explodes. A detonator can easily explode aqueous solutions concentrated above 80% by weight, and even 50% solution might prove detonable if tested in bulk.[16][17] In air, the combustion is rapid and complete:

4 NH2OH + O2 → 2 N2 + 6 H2O

Absent air, pure hydroxylamine requires stronger heating and the detonation does not complete combustion:

3 NH2OH → N2 + NH3 + 3 H2O

Partial

isomerisation to the amine oxide H3N+−O− contributes to the high reactivity.[18]

Conjugate oxoacids

Hydroxylamine yields via

oxidation to azinic acid.[citation needed] Further attempted oxidation yields nitric acid, and finally orthonitrate
.

More hydroxyl radicals substitute the hydrogen atoms to yield azonous acid & azorous acid.

Functional group

See also: Hydroxamic acid
Secondary N,N-hydroxylamine schema

Weinreb amides
.

Similarly to amines, one can distinguish hydroxylamines by their degree of substitution: primary, secondary and tertiary. When stored exposed to air for weeks, secondary hydroxylamines degrade to nitrones.[19]

N-organylhydroxylamines, R−NH−OH, where R is an

organyl group, can be reduced to amines R−NH2:[20]

R−NH−OH (Zn, HCl) → R−NH2 + ZnO

Synthesis

Amine oxidation with benzoyl peroxide is the most common method to synthesize hydroxylamines. Care must be taken to prevent over-oxidation to a nitrone. Other methods include:

Uses

Conversion of cyclohexanone to caprolactam involving the Beckmann rearrangement.

Approximately 95% of hydroxylamine is used in the synthesis of cyclohexanone oxime, a precursor to Nylon 6.[10] The treatment of this oxime with acid induces the Beckmann rearrangement to give caprolactam (3).[21] The latter can then undergo a ring-opening polymerization to yield Nylon 6.[22]

Laboratory uses

Hydroxylamine and its salts are commonly used as reducing agents in myriad organic and inorganic reactions. They can also act as antioxidants for fatty acids.

High concentrations of hydroxylamine are used by biologists to introduce mutations by acting as a DNA nucleobase amine-hydroxylating agent.[23] In is thought to mainly act via hydroxylation of cytidine to hydroxyaminocytidine, which is misread as thymidine, thereby inducing C:G to T:A transition mutations.[24] But high concentrations or over-reaction of hydroxylamine in vitro are seemingly able to modify other regions of the DNA & lead to other types of mutations.[24] This may be due to the ability of hydroxylamine to undergo uncontrolled free radical chemistry in the presence of trace metals and oxygen, in fact in the absence of its free radical affects Ernst Freese noted hydroxylamine was unable to induce reversion mutations of its C:G to T:A transition effect & even considered hydroxylamine to be the most specific mutagen known.[25] Practically, it has been largely surpassed by more potent mutagens such as EMS, ENU, or nitrosoguanidine, but being a very small mutagenic compound with high specificity, it found some specialized uses such as mutation of DNA packed within bacteriophage capsids,[26] & mutation of purified DNA in vitro.[27]

This route also involves the Beckmann Rearrangement, like the conversion from cyclohexanone to caprolactam.

An

ketoxime
with hydroxylamine.

Some non-chemical uses include removal of hair from animal hides and photographic developing solutions.[2] In the semiconductor industry, hydroxylamine is often a component in the "resist stripper", which removes photoresist after lithography.

Hydroxylamine can also be used to better characterize the nature of a post-translational modification onto proteins. For example, poly(ADP-Ribose) chains are sensitive to hydroxylamine when attached to glutamic or aspartic acids but not sensitive when attached to serines.[28] Similarly, Ubiquitin molecules bound to serines or threonines residues are sensitive to hydroxylamine, but those bound to lysine (isopeptide bond) are resistant.[29]

Biochemistry

In biological nitrification, the oxidation of NH3 to hydroxylamine is mediated by the

Hydroxylamine oxidoreductase (HAO) further oxidizes hydroxylamine to nitrite.[30]

ammonia-oxidizing bacteria Nitrosomonas europea, can convert hydroxylamine to nitrous oxide, a potent greenhouse gas.[31]

Hydroxylamine can also be used to highly selectively cleave

oxygen-evolving complex
of photosynthesis on account of its similar structure to water.

Safety and environmental concerns

With a theoretical decomposition energy of about 5 kJ/g, hydroxylamine is an explosive, and aqueous solutions above 80% can be easily detonated by detonator or strong heating under confinement.[16] [17] At least two factories dealing in hydroxylamine have been destroyed since 1999 with loss of life.[33] It is known, however, that ferrous and ferric iron salts accelerate the decomposition of 50% NH2OH solutions.[34] Hydroxylamine and its derivatives are more safely handled in the form of salts.

It is an irritant to the

mucous membranes. It may be absorbed through the skin, is harmful if swallowed, and is a possible mutagen.[35]

See also

References

  1. ISBN 978-0-85404-182-4
    .
  2. ^
    ISBN 0-8493-0487-3
    .
  3. ISBN 978-1-903996-65-2
    .
  4. ^ a b c Greenwood and Earnshaw. Chemistry of the Elements. 2nd Edition. Reed Educational and Professional Publishing Ltd. pp. 431–432. 1997.
  5. ^
    PMID 24523098
    .
  6. ^ W. C. Lossen (1865) "Ueber das Hydroxylamine" (On hydroxylamine), Zeitschrift für Chemie, 8 : 551-553. From p. 551: "Ich schlage vor, dieselbe Hydroxylamin oder Oxyammoniak zu nennen." (I propose to call it hydroxylamine or oxyammonia.)
  7. ^ C. A. Lobry de Bruyn (1891) "Sur l'hydroxylamine libre" (On free hydroxylamine), Recueil des travaux chimiques des Pays-Bas, 10 : 100-112.
  8. ^ L. Crismer (1891) "Préparation de l'hydroxylamine cristallisée" (Preparation of crystalized hydroxylamine), Bulletin de la Société chimique de Paris, series 3, 6 : 793-795.
  9. ISBN 9780470132401
    .
  10. ^
    ISBN 978-3527306732
    .
  11. ^ James Hale, Arthur (1919). The Manufacture of Chemicals by Electrolysis (1st ed.). New York: D. Van Nostrand Co. p. 32. Retrieved 5 June 2014. manufacture of chemicals by electrolysis hydroxylamine 32.
  12. ^ Osswald, Philipp; Geisler, Walter (1941). Process of preparing hydroxylamine hydrochloride (US2242477) (PDF). U.S. Patent Office.
  13. PMID 38378822
    .
  14. ^ Ralph Lloyd Shriner, Reynold C. Fuson, and Daniel Y. Curtin, The Systematic Identification of Organic Compounds: A Laboratory Manual, 5th ed. (New York: Wiley, 1964), chapter 6.
  15. ISBN 978-0-12-352651-9
    .
  16. ^
    ISSN 0950-4230
    .
  17. ^
    ISBN 9780081009710
    . Retrieved 2023-08-28.
  18. PMID 20449284
    .
  19. doi:10.1021/cr60230a006
    .
  20. ^ Smith, Michael and Jerry March. March's advanced organic chemistry : reactions, mechanisms, and structure. New York. Wiley. p. 1554. 2001.
  21. ISBN 978-0-19-927029-3
    .
  22. doi:10.3390/polym5020361
    .
  23. PMID 16406304
    .
  24. ^
    PMID 7042980
    .
  25. OCLC 851813793
    .
  26. PMID 4943557
    .
  27. ^ Forsberg, Susan. "Hydroxylamine Mutagenesis of plasmid DNA". PombeNet. University of Southern California. Retrieved 9 December 2021.
  28. PMID 34795260
    .
  29. PMID 31209050
    .
  30. PMID 8369308
    .
  31. PMID 27856762
    .
  32. PMID 927171.{{cite book}}: CS1 maint: multiple names: authors list (link
    )
  33. ^ Japan Science and Technology Agency Failure Knowledge Database Archived 2007-12-20 at the Wayback Machine.
  34. doi:10.1021/je030121p
    .
  35. ^ MSDS Sigma-Aldrich

Further reading

  • Hydroxylamine[permanent dead link]
  • Walters, Michael A. and Andrew B. Hoem. "Hydroxylamine." e-Encyclopedia of Reagents for Organic Synthesis. 2001.
  • Schupf Computational Chemistry Lab
  • M. W. Rathke A. A. Millard "Boranes in Functionalization of Olefins to Amines: 3-Pinanamine" Organic Syntheses, Coll. Vol. 6, p. 943; Vol. 58, p. 32. (preparation of hydroxylamine-O-sulfonic acid).

External links

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