Chemical Properties
slightly yellow liquid
Definition
ChEBI: The simplest hydroxylamine, consisting of ammonia bearing a hydroxy substituent. It is an intermediate in the biological nitrification by microbes like bacteria.
General Description
Odorless white crystalline solid. Sinks and mixes with water.
Reactivity Profile
HYDROXYLAMINE(7803-49-8) is a white solid, thermally unstable, decomposes rapidly at room temperature or when dissolved in hot water by internal oxidation-reduction. HYDROXYLAMINE(7803-49-8) should be stored below 10° C [Bailar, 1973, vol. 2, p. 272]. Explosive reaction with strong oxidizers (chromium trioxide, potassium dichromate) or powdered zinc upon heat. Reaction with zinc or calcium produces explosive bishydroxylamides. HYDROXYLAMINE(7803-49-8) ignites on contact with cupric sulfate, alkali metals (sodium, potassium), oxidants (e.g., barium oxide, barium peroxide, lead dioxide, potassium permanganate, chlorine), phosphorus trichloride and pentachloride. HYDROXYLAMINE(7803-49-8) reacts vigorously with hypochlorites, pyridine, carbonyls [Sax, 9th ed., 1996, p. 1875]. On contact with organic materials in thin layer (e.g., crystals on filter paper), HYDROXYLAMINE(7803-49-8) may ignite spontaneously in air. HYDROXYLAMINE(7803-49-8) explodes when heated above 70° C [Brauer, 1963, vol. 1, p. 502]. During a distillation process, an explosion occurred. Potassium hydroxide is thought to be involved in the explosion. Employees in the plant complained of chest pains and suffered chemical burns. Five people were killed by the explosion.
Air & Water Reactions
Decomposes rapidly at room temperature or when dissolved in hot water by internal oxidation-reduction. Reacts with water or steam to produce heat and corrosive liquids.
Hazard
Decomposes rapidly at room temperature,
violently when heated, detonates in flame-heated
test tube. Irritant to tissue.
Health Hazard
INHALATION: Moderately toxic by inhalation and oral routes with the following symptoms possible: headache, vertigo, tinnitus, dyspnea, nausea and vomiting, cyanosis, proteinuria and hematuria, jaundice, restlessness, and convulsion. Methemoglobinemia has been reported. EYES: Corrosive-highly irritating. SKIN: Irritating or corrosive to skin. INGESTION: Moderately toxic by inhalation and oral routes with the following symptoms possible; headache, vertigo, tinnitus, dyspnea, nausea and vomiting, cyanosis, proteinuria and hematuria, jaundice, restlessness, and convulsion. Methemoglobinemia has been reported.
Physical properties
White crystalline solid; orthogonal plates or needles; unstable; density 1.21g/cm3at 20°C; melts at 33°C; vaporizes at 58°C; very soluble in water, liquidammonia and lower alcohols; sparingly soluble in most other organic solvents;decomposes in hot water; pKa5.94 at 25°C.
Preparation
Hydroxylamine is unstable as a free base. It is prepared from hydroxy-lamine hydrochloride, NH2OH?HCl, which is obtained by electrolytic reduc-tion of ammonium chloride solution. The hydrochloride undergoes alkalinedecomposition to hydroxylamine, which is collected by vacuum distillation.
Potential Exposure
Potential Exposure:Mutagen.Those involved in chemical synthesis or use of hydroxyI-amine. Used as a reducing agent.
First aid
If this chemical gets into the eyes, remove any con-tact lenses at once and irrigate immediately for at least 15 min,occasionally lifting upper and lower lids. Seek medical atten-tion immediately. If this chemical contacts the skin, removecontaminated clothing and wash immediately with soap andwater. Seek medical attention immediately. If this chemicalhas been inhaled, remove from exposure, begin rescue breath-ing (using universal precautions, including resuscitation mask)if breathing has stopped and CPR if heart action has stopped.Transfer promptly to a medical facility. When this chemicalhas been swallowed, get medical attention. If victim is con-scious, administer water or milk. Do not induce vomiting.Note to physician: Treat for methemoglobinemia. Test urineformethemoglobinemia. Spectrophotometry may berequired for precise determination of levels of methemoglo-bin in urine.
Carcinogenicity
Carcinogenicity of hydroxylamine and
its salts has not been demonstrated. Several
studies have shown a decreased incidence of
spontaneous mammary tumors in mice exposed
to the sulfate and hydrochloride.3–7 There was
some indication of an increase in the incidence
of spontaneous mammary tumors when the
sulfate was administered to older animals
whose mammary glands were already well
developed.
Environmental Fate
The large-scale production and use of hydroxylamine may
result in its release to the environment through various waste
streams. Hydroxylamine will exist solely as a vapor in the
ambient atmosphere, and will be degraded in the atmosphere
by reaction with photochemically produced hydroxyl radicals;
the half-life for this reaction in air is estimated to be 18 h.
Abiotic degradation of hydroxylamine by photochemically
produced peroxy radicals is an important environmental fate
process in surface waters, with the half-life of the reaction
measured at approximately 2 h. An estimated bioconcentration
factor of 3 suggests that the potential for bioconcentration in
aquatic organisms is low. If released terrestrially, hydroxylamine
will most likely exist in its protonated form due to its
pKa of 5.94; the protonated form is nonvolatile. Koc estimates
of 14 for hydroxylamine suggest that it may have very high
mobility in soil.
storage
(1) Color Code- Yellow Stripe (strong reducingagent): Reactivity Hazard; Store separately in an area iso-lated from flammables, combustibles, or other yellow-codedmaterials. (2) Color Code- Blue: Health Hazard/Poison:Store in a secure poison location. Prior to working with thischemical you should be trained on its proper handling andstorage. Protect against physical damage. Store in cool, non-combustible buildings and separate from oxidizing materi-als. Open airtight containers occasionally to relieve pressurefrom decomposition products.
Shipping
Toxic solid, corrosive, inorganic, n.o.s. requires ashipping label of“POISONOUS/TOXIC MATERIALS,CORROSIVE.”It falls in DOT/UN Hazard Class 6.1 andPacking Group II.
Purification Methods
Crystallise it from n-butanol at -10o, collect it by vacuum filtration and wash it with cold diethyl ether. Harmful vapours. [Hurd Inorg Synth I 87 1939, Semon in Org Synth Coll Vol I 318 1932.]
Toxicity evaluation
Hydroxylamine acts as a reducing agent when absorbed
systemically, producing methemoglobin and the formulation
of Heinz bodies in the blood. It can induce hemolytic anemia.
It inhibits platelet aggregation and is a nitric oxide vasodilator.
Oxylamines such as hydroxylamine and methoxylamine
disturb DNA replication and act as potent mutagens, causing
nucleotide transition from one purine to another or one
pyrimidine to another.
Allergic reactions of the skin following dermal exposure to
hydroxylamine resemble contact eczema, or possibly urticaria
of Quincke’s edema. The pathogenesis of this reaction appears
to be mediated by a delayed type T-lymphocyte reaction.
Incompatibilities
Self reactive. Contaminants， tempera-tures above 129.4℃, or open flame can cause explosivedecomposition, especially in the presence of moisture andcarbon dioxide. Incompatible with strong acids, organicanhydrides, isocyanates, aldehydes, sodium, finely dividedzinc, some metal oxides. Aqueous solution is a weak base.Contact with strong oxidizers may cause a fire and explo-sion hazard. Attacks some metals. Contact with calcium orzinc forms a heat-sensitive explosive [bis(hydroxylamide)](Sax).
