Nitrophenols are compounds of the formula HOC₆H_5−x(NO₂)_x. The conjugate bases are called nitrophenolates. Nitrophenols are more acidic than

phenol Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it req ...

itself.

Mono-nitrophenols

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...

HOC₆H₄NO₂. Three

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Iso ...

ic nitrophenols exist: * ''o''-Nitrophenol (2-nitrophenol; OH and NO₂ groups are neighboring; CAS number: 88-75-5), a yellow crystalline solid (m.p. 46 °C). * ''m''-Nitrophenol (3-nitrophenol, CAS number: 554-84-7), a yellow solid (m.p. 97 °C) and precursor to the drug

mesalazine Mesalazine, also known as mesalamine or 5-aminosalicylic acid (5-ASA), is a medication used to treat inflammatory bowel disease, including ulcerative colitis and Crohn's disease. It is generally used for mildly to moderately severe disease. It ...

(5-aminosalicylic acid). * ''p''-Nitrophenol (4-nitrophenol, CAS number: 100-02-7), yellow crystals (m.p. 114 °C). It is a precursor to the

rice Rice is the seed of the grass species ''Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima ''Oryza glaberrima'', commonly known as African rice, is one of the two domesticated rice species. It was first domesticated and grown i ...

herbicide fluorodifen, the pesticide

parathion Parathion, also called parathion-ethyl or diethyl parathion and locally known as "Folidol", is an organophosphate insecticide and acaricide. It was originally developed by IG Farben in the 1940s. It is highly toxic to non-target organisms, incl ...

, and the human analgesic

paracetamol Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. Common brand names include Tylenol and Panadol. At a standard dose, paracetamol only slightly decreases body temperature; it is inferior ...

(also known as acetaminophen). The mononitrated phenols are often

hydrogenated Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic co ...

to the corresponding

aminophenol Aminophenol may refer to any of three isomeric chemical compounds: * 2-Aminophenol * 3-Aminophenol * 4-Aminophenol They are simultaneously an aniline and a phenol Phenol (also called carbolic acid) is an aromatic organic compound with th ...

s that are also useful industrially.

Di- and trinitrophenols

2,4-Dinitrophenol 2,4-Dinitrophenol (2,4-DNP or simply DNP) is an organic compound with the formula HOC6H3(NO2)2. It is a yellow, crystalline solid that has a sweet, musty odor. It sublimates, is volatile with steam, and is soluble in most organic solvents as well ...

(m.p. 83 °C) is a moderately strong acid (pK_a = 4.89). * 2,4,6-Trinitrophenol is better known as

picric acid Picric acid is an organic compound with the formula (O2N)3C6H2OH. Its IUPAC name is 2,4,6-trinitrophenol (TNP). The name "picric" comes from el, πικρός (''pikros''), meaning "bitter", due to its bitter taste. It is one of the most acidic ...

, which has a well-developed chemistry.

Safety

Nitrophenols are poisonous. Occasionally, nitrophenols contaminate the soil near former explosives or fabric factories and military plants, and current research is aimed at remediation.Fact sheet at atsdr.cdc.gov
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References

{{Authority control Nitrobenzenes Phenols