Application
The main and the most significant use of 4-Aminophenol is for the manufacturing of Paracetamol, an analgesic and antipyretic drug. In addition to paracetamol, it is a key element in the synthesis of pharmaceutical ingredients and important industrial chemicals like Acebutolol, Ambroxol, Sorafenib and so on.
p-aminophenol is widely used in preparation of fabric dyes and hair dyes, and is also used as a developing agent in photography for creating black and white images. It acts as a corrosion inhibitor in paints and as anti-corrosive lubricating agent in 2-cycle engines. It is also used as a wood stain, giving rose-like colour to timber. p-Aminophenol is one of key ingredients for synthesis of rubber antioxidants. Moreover, it is often used as a reagent for analysing metals like Copper, Magnesium, Vanadium and Gold, compounds like Nitrites and Cyanates, and antioxidants.
Definition
ChEBI: 4-aminophenol is an amino phenol (one of the three possible isomers) which has the single amino substituent located para to the phenolic -OH group. It has a role as a metabolite and an allergen.
General Description
P-aminophenol appears as white or reddish-yellow crystals or light brown powder. Turns violet when exposed to light. (NTP, 1992)
Air & Water Reactions
Insoluble in water.
Reactivity Profile
Heat (decomposition forming HCN, nitrous vapors, CO); water (CO2); reacts violently with acids, bases, alcohols and amines causing fire and explosion hazards [Handling Chemicals Safely 1980 p. 647].
Health Hazard
p-Aminophenol is of moderately
low toxicity but has caused dermal sensitization
and kidney injury; the potential for producing
methemoglobin is of relatively minor
importance.
The oral LD50 in rats was 671 mg/kg.1
Effects included central nervous system
depression. A solution of 2.5% applied to
abraded skin of rabbits was a mild irritant.1 p-
Aminophenol caused dermal sensitization in
guinea pigs, and skin sensitization has been
reported in humans.2,3 The dermal LD50 in
rabbits was greater than 8 g/kg, which strongly
suggests that absorption through the skin is
minimal.4 Single nonlethal acute doses in rats
produced proximal renal tubular necrosis of the
pars recta.
Fire Hazard
Flash point data are not available for 4-Aminophenol. 4-Aminophenol is probably combustible.
Flammability and Explosibility
Nonflammable
Potential Exposure
Workers may be exposed to oAminophenol during its use as a chemical intermediate; in the manufacture of azo and sulfur dyes; and in the photographic industry. There is potential for consumer exposure to o-Aminophenol because of its use in dyeing hair, fur, and leather. The compound is a constituent of 75 registered cosmetic products suggesting the potential for widespread consumer exposure. p-Aminophenol is used mainly as a dye, dye intermediate and as a photographic developer; and in small quantities in analgesic drug preparation. Consumer exposure to p-aminophenol may occur from use as a hairdye or as a component in cosmetic preparations. m-Aminophenol is used mainly as a dye intermediate.
Solubility in organics
Very soluble in dimethylsulfoxide Soluble in acetonitrile, ethyl acetate, and acetone Slightly soluble in toluene, diethyl ether, and ethanol Negligible solubility in benzene and chloroform
Shipping
UN2512 Aminophenols (o-; m-; p-), Hazard Class: 6.1; Labels: 6.1-Poisonous materials
Purification Methods
Crystallise it from EtOH, then water, excluding oxygen. It sublimes at 110o/0.3mm. It has been purified by chromatography on alumina with a 1:4 (v/v) mixture of absolute EtOH/*benzene as eluent. [Beilstein 13 IV 1014.]
Incompatibilities
These phenol/cresol materials can react with oxidizers; reaction may be violent. Incompatible with strong reducing substances such as alkali metals, hydrides, nitrides, and sulfides. Flammable gas (H2) may be generated, and the heat of the reaction may cause the gas to ignite and explode. Heat may be generated by the acidbase reaction with bases; such heating may initiate polymerization of the organic compound. Reacts with boranes, alkalies, aliphatic amines, amides, nitric acid, sulfuric acid. Phenols are sulfonated very readily (e.g., by concentrated sulfuric acid at room temperature). These reactions generate heat. Phenols are also nitrated very rapidly, even by dilute nitric acid and can explode when heated. Many phenols form metal salts that may be detonated by mild shock.
Waste Disposal
Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.
