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CAS NUMBER: 7803-49-8
EC NUMBER: 232-259-2
MOLECULAR FORMULA: NH2OH
MOLECULAR WEIGHT: 33.030
IUPAC NAME: hydroxylamine
Hydroxylamine is an odorless white crystalline solid.
Hydroxylamine Sinks and mixes with water.
Hydroxylamine is the simplest hydroxylamine, consisting of ammonia bearing a hydroxy substituent.
Hydroxylamine is an intermediate in the biological nitrification by microbes like bacteria.
Hydroxylamine has a role as:
-a nitric oxide donor
-an EC 1.1.3.13 (alcohol oxidase) inhibitor
-a nucleophilic reagent
-an EC 4.2.1.22 (cystathionine beta-synthase) inhibitor
-an EC 4.3.1.10 (serine-sulfate ammonia-lyase) inhibitor
-a bacterial xenobiotic metabolite and an algal metabolite.
Hydroxylamine is a conjugate acid of a hydroxyazanide and an aminooxidanide.
Hydroxylamine derives from a hydride of an ammonia.
Hydroxylamine is an inorganic compound with the formula NH2OH.
The pure material is a white, unstable crystalline, hygroscopic compound.
However, hydroxylamine is almost always provided and used as an aqueous solution.
Hydroxylamine is used to prepare oximes, an important functional group.
Hydroxylamine is also an intermediate in biological nitrification. In biological nitrification, the oxidation of NH3 to hydroxylamine is mediated by the enzyme ammonia monooxygenase (AMO).
Hydroxylamine oxidoreductase (HAO) further oxidizes hydroxylamine to nitrite
History of Hydroxylamine:
Hydroxylamine was first prepared as hydroxylamine hydrochloride in 1865 by the German chemist Wilhelm Clemens Lossen (1838-1906)
Hydroxylamine reacted tin and hydrochloric acid in the presence of ethyl nitrate.
Hydroxylaminewas first prepared in pure form in 1891 by the Dutch chemist Lobry de Bruyn and by the French chemist Léon Maurice Crismer (1858-1944).
The coordination complex ZnCl2(NH2OH)2, known as Crismer's salt, releases hydroxylamine upon heating
Reactions:
Hydroxylamine reacts with electrophiles, such as alkylating agents, which can attach to either the oxygen or the nitrogen atoms:
R-X + NH2OH → R-ONH2 + HX
R-X + NH2OH → R-NHOH + HX
The reaction of NH2OH with an aldehyde or ketone produces an oxime.
R2C=O + NH2OH∙HCl , NaOH → R2C=NOH + NaCl + H2O
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.
Oximes, e.g., dimethylglyoxime, are also employed as ligands.
NH2OH reacts with chlorosulfonic acid to give hydroxylamine-O-sulfonic acid, a useful reagent for the synthesis of caprolactam.
HOSO2Cl + NH2OH → NH2OSO2OH + HCl
The hydroxylamine-O-sulfonic acid, which should be stored at 0 °C to prevent decomposition, can be checked by iodometric titration.
Hydroxylamine (NH2OH), or hydroxylamines (R-NHOH) can be reduced to amines.
NH2OH (Zn/HCl) → NH3
R-NHOH (Zn/HCl) → R-NH2
Hydroxylamine explodes with heat:
4 NH2OH + O2 → 2 N2 + 6 H2O
The high reactivity comes in part from the partial isomerisation of the NH2OH structure to ammonia oxide (also known as azane oxide), with structure NH3+O−
Functional Group:
Substituted derivatives of hydroxylamine are known.
If the hydroxyl hydrogen is substituted, this is called an O-hydroxylamine
if one of the amine hydrogens is substituted, this is called an N-hydroxylamine.
In general N-hydroxylamines are the more common.
Similarly to ordinary amines, one can distinguish primary, secondary and tertiary hydroxylamines, the latter two referring to compounds where two or three hydrogens are substituted, respectively.
Examples of compounds containing a hydroxylamine functional group are N-tert-butyl-hydroxylamine or the glycosidic bond in calicheamicin.
N,O-Dimethylhydroxylamine is a coupling agent, used to synthesize Weinreb amides.
Synthesis:
The most common method for the synthesis of substituted hydroxylamines is the oxidation of an amine with benzoyl peroxide.
Some care must be taken to prevent over-oxidation to a nitrone.
Other methods include:
-Hydrogenation of an oxime
-Alkylation of hydroxylamine
-The thermal degradation of amine oxides via the Cope reaction
Uses oF Hydroxylamine:
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.
In the synthesis of Nylon 6, cyclohexanone is first converted to its oxime by condensation with hydroxylamine.
The treatment of this oxime with acid induces the Beckmann rearrangement to give caprolactam .
The latter can then undergo a ring-opening polymerization to yield Nylon 6.
The nitrate salt, hydroxylammonium nitrate, is being researched as a rocket propellant, both in water solution as a monopropellant and in its solid form as a solid propellant.
High concentrations of hydroxylamine are used by biologists to introduce mutations by acting as a DNA nucleobase amine-hydroxylating agent.
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.
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.
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 it's 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.
Practically, it has been largely surpassed by more potent mutagents 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, & mutation of purified DNA in vitro.
Hydroxylamine can also be used to highly selectively cleave asparaginyl-glycine peptide bonds in peptides and proteins.
Hydroxylamine also bonds to and permanently disables (poisons) heme-containing enzymes.
Hydroxylamine is used as an irreversible inhibitor of the oxygen-evolving complex of photosynthesis on account of its similar structure to water.
An alternative industrial synthesis of paracetamol developed by Hoechst–Celanese involves the conversion of ketone to a ketoxime with hydroxylamine.
Some non-chemical uses include removal of hair from animal hides and photographic developing solutions.
In the semiconductor industry, hydroxylamine is often a component in the "resist stripper", which removes photoresist after lithography.
USES OF HYDROXYLAMINE:
Hydroxylamine is used As reducing agent in photography
Hydroxylamine is used in synthetic and analytical chemistry
Hydroxylamine is used to purify aldehydes and ketones
Hydroxylamine is used as antioxidant for fatty acids and soaps
Hydroxylamine is used as dehairing agent for hides
Over 95% of hydroxylamine produced is used for the production of cyclohexanone oxime or caprolactam.
Aqueous solutions of hydroxylamine are always used in chemical reactions.
Hydroxylamine is an important and effective reagent for the preparation of oximes.
Hydroxylamine is also an intermediate of biological nitrification.
Hydroxylamine and its salts are commonly used as reducing agents in countless organic and inorganic reactions.
They can also act as antioxidants for fatty acids.
In the synthesis of Nylon 6, cyclohexanone is first converted to its oxime by condensation with hydroxylamine.
Hydroxylamine can also be used to highly selectively cleave asparaginyl-glycine peptide bonds in peptides and proteins.
Hydroxylamine also bonds to and permanently disables heme-containing enzymes.
Hydroxylamine is used as an irreversible inhibitor of the oxygen-evolving complex of photosynthesis on account of its similar structure to water.
An alternative industrial synthesis of paracetamol developed by Hoechst–Celanese involves the conversion of ketone to a ketoxime with hydroxylamine.
Some non-chemical uses include removal of hair from animal hides and photographic developing solutions.
In the semiconductor industry, hydroxylamine is often a component in the ‘resist stripper’ which removes photoresist after lithography.
Hydroxylamine is used as:
-chemıcal ıntermedıate for mıscellaneous organıc & ınorganıc chemıcals (ın lab);
-reducıng agent;
-chemıcal ıntermedıate (captıvely) for caprolactam used ın nylon 6;
-absorbent for removıng nıtrogen dıoxıde;
-termınatıon agent ın peroxıde-catalyzed polymerızatıons;
-agent ın developers for photographıc sılver emulsıons
hydroxylamine is an oxygenated derivative of ammonia
Hydroxylamine is used in the synthesis of oximes from aldehydes and ketones.
Hydroxylamine is reduced easily to amines, which are used in the manufacture of:
-dyes
-plastics
-synthetic fibres
-medicinals
the oxime of cyclohexanone can be converted to its isomer epsilon-caprolactam, from which nylon-6 is made.
Hydroxylamine and its inorganic salts are powerful reducing agents used in the preparation of polymers and as constituents of photographic developers.
Hydroxylamine may be prepared by several methods; of current technical importance are the hydrolysis of nitroalkanes (RCH2NO2) and the catalytic hydrogenation of nitric oxide (NO).
Pure hydroxylamine is a colourless, crystalline solid.
An unstable compound, decomposing to nitric oxide and hydrogen
Hydroxylamine is usually handled in the form of salts.
Hydroxylamine is a colorless odorless nitrogenous base NH3O that resembles ammonia in its reactions but is less basic and that is used especially as a reducing agent
Hydroxylamine is an unstable, weakly basic, crystalline compound,
Hydroxylamine is used as a reducing agent, analytical reagent, and chemical intermediate.
Hydroxylamine is a nitrogenous inorganic compound with chemical formula, NH2-OH. Hydroxylamine is also known as:
-azinous acid
-aminol
-azanol
-hydroxyazane
-nitrinous acid
When one hydrogen atom of ammonia is replaced by an –OH functional group, then the obtaining compound is called hydroxylamine.
There are different types of hydroxylamine, namely, methyl hydroxylamine, ethyl hydroxylamine, phenyl hydroxylamine etc.
Hydroxylamine is a colorless solid which melts at 306K temperature. Pure hydroxylamine is a white crystalline, hygroscopic compound.
Hydroxylamine is unstable compound and decomposes violently even at 293K temperature to ammonia, nitrogen and water. The boiling point of hydroxylamine is 331K.
Hydroxylamine is freely soluble in water and lower alcohols
What is Formula and Lewis dot structure of Hydroxylamine?
Hydroxylamine or aminol is an inorganic compound with molecular formula, NH2OH. It is polar covalent compound.
The central nitrogen atom is directly attached with two hydrogen atoms and one oxygen atom. The nitrogen atom is sp3 hybridized.
So the co-ordination geometry of hydroxylamine is trigonal at ’N’ and the molecular shape is tetrahedral at ‘N’.
Hydroxylamine Preparation:
Hydroxylamine is prepared by the reduction of nitrites with SO2 under certain condition.
At first, a concentration solution of NaNO2 is mixed with a solution of Na2CO3.
Then SO2 is passed at a temperature below 276K, till the solution becomes just acidic.
It is two steps process.
In the first step, SO2 reacts with sodium carbonate to give NaHSO3 and NaHCO3.
In the second step, NaHSO3 reacts with sodium nitrite to give hydroxylamine sodium sulphonate salt.
This sulphonate salt can be easily hydrolysed to the expected hydroxylamine.
Is Hydroxylamine Acid or Base?
The ‘N’-atom of hydroxylamine sp3 hybridized and it contains one lone pair of electron.
Hydroxylamine can donate this lone pair of electron to electron deficient species (atom, molecules or ions). So hydroxylamine acts as Lewis base.
NH2-OH + H+ ⟶ NH3-OH+
The pKb value of hydroxylamine is 7.96. This means that, it is a weak base.
On the other hand, O — H bond in hydroxylamine is polar one due to electronegativity difference between oxygen and hydrogen elements.
Hence it can easily break and release H+ ion. Consequently, in this case hydroxylamine behaves as an acid.
NH2-O-H ⟶ NH2O- + H+
The pKa value of hydroxylamine is 6.02. This means that, it is a weak acid.
What is the action of hydroxylamine on glucose?
Generally, hydroxylamine reacts with such compounds which contain aldehyde and keto groups.
Now glucose contains aldehyde group (-CHO).
Hence hydroxylamine reacts with glucose and forms oxime, namely glucose oxime.
Hydroxylamine is a reactive chemical with formula NH2OH.
Hydroxylamine can be considered a hybrid of ammonia and water due to parallels it shares with each.
At room temperature pure NH2OH is ordinarily a white, unstable crystalline, hygroscopic compound
however it is almost always encountered as an aqueous solution.
Hydroxylamine tends to be explosive, and the nature of the hazard is not entirely understood.
At least two factories dealing in hydroxylamine have been destroyed since 1999 with loss of life.
Hydroxylamine is known, however, that ferrous and ferric iron accelerate the decomposition of 50% NH2OH solutions.
Hydroxylamine and its derivatives are more safely handled in the form of salts.
Hydroxylamine is an intermediate in biological nitrification.
The oxidation of NH3 is mediated by HAO (hydroxylamine oxidoreductase).
Hydroxylamine is a reactive chemical with formula NH2OH.
Hydroxylamine can be considered a hybrid of ammonia and water due to parallels it shares with each.
At room temperature pure Hydroxylamine is ordinarily a white, unstable crystalline, hygroscopic compound;
Hydroxylamine is a reactive chemical with formula NH2OH.
Hydroxylamine can be considered a hybrid of ammonia and water due to parallels it shares with each.
At room temperature pure Hydroxylamine is unstable crystalline, hygroscopic compound;
however it is almost always encountered as an aqueous solution.
PHYSICAL PROPERTIES OF HYDROXYLAMINE:
-Molecular Weight: 33.030
-XLogP3-AA: -1.2
-Exact Mass: 33.021463719
-Monoisotopic Mass: 33.021463719
-Topological Polar Surface Area: 46.2 Ų
-Odor: odorless
-Color: white
-Form: crystalline solid
-Boiling Point: 70 °C
-Melting Point: 33°C
-Flash Point: explodes at 129 °C
-Solubility: Soluble in alcohol, acids, and cold water
-Density: 1.227
-Vapor Density: Relative vapor density (air = 1): 1.1
-Vapor Pressure: 53 mm Hg at 32 °C
-LogP: -1.5
-Autoignition Temperature: 265 °F
Hydroxylamine is an intermediate in biological nitrification.
The oxidation of NH3 is mediated by hydroxylamine oxidoreductase (HAO).
however it is almost always encountered as an aqueous solution.
Hydroxylamine is a colorless inorganic compound (HONH2) used in organic synthesis and as a reducing agent, due to its ability to donate nitric oxide.
Hydroxylamine may explode on heating.
Hydroxylamine is an intermediate in the biological nitrification.
The oxidation of NH3 is mediated by HAO (hydroxylamine oxidoreductase).
Hydroxylamine is found in gram bean and mung bean.
CHEMICAL PROPERTIES OF HYDROXYLAMINE:
-Hydrogen Bond Donor Count: 2
-Hydrogen Bond Acceptor Count: 2
-Rotatable Bond Count: 0
-pKa: 5.94
-Polarizability: 2.78 ų
-Formal Charge: 0
-Complexity: 2
-Isotope Atom Count: 0
-Defined Atom Stereocenter Count: 0
-Undefined Atom Stereocenter Count: 0
-Defined Bond Stereocenter Count: 0
-Undefined Bond Stereocenter Count: 0
-Covalently-Bonded Unit Count: 1
-Compound Is Canonicalized: Yes
-Heavy Atom Count: 2
STORAGE OF HYDROXYLAMINE:
Hydroxylamine should be kept away from places where it can get moisture.
Hydroxylamine should preferably be stored in glass bottles.
Hydroxylamine should be stored in a clean, well-ventilated place
Hydroxylamine should be stored in tightly closed containers.
Hydroxylamine should be stored separately from other reagents.
Hydroxylamine should be stored in a moisture-free environment.
Hydroxylamine should be stored at its specific temperatures
Hydroxylamine should be stored at constant atmospheric pressure.
SYNONYMS:
hydroxylamine
Oxammonium
Nitroxide
Oxyammonia
hydroxyazanyl
dihydridohydroxidonitrogen
Nitrogen oxides
Nitrinous acid
Nitrogen oxide (NOx)
arninoalcohol
hyroxylamine
Hydroxylamin
amino alcohol
amino-alcohol
hydroxy amine
hydroxyl amine
hydroxyl-amine
azinous acid
N-hydroxyamine
amine N-oxide
(1) hydroxylamine
(hydroxyamino)methanol
Hydroxylamine (50% solution in water)
