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Skeletal formula of o-anisidine
Ball-and-stick model of the o-anisidine molecule
Preferred IUPAC name
Other names
o-Anisidine (no longer recommended[1])
3D model (JSmol)
ECHA InfoCard 100.001.785
EC Number 201-963-1
RTECS number BZ5410000
UN number 2431
Molar mass 123.16 g·mol−1
Appearance Yellow liquid, turns brown upon exposure to air
Density 1.0923 g/cm3
Melting point 6.2 °C (43.2 °F; 279.3 K)
Boiling point 224 °C (435 °F; 497 K)
1.5 g/100 ml
Solubility soluble in ethanol, diethyl ether, acetone, benzene
-80.44·10−6 cm3/mol
Main hazards potential occupational carcinogen[3]
GHS pictograms The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word Danger
H301, H311, H331, H341, H350
P201, P202, P261, P264, P270, P271, P280, P281, P301+310, P302+352, P304+340, P308+313, P311, P312, P321, P322, P330, P361, P363, P403+233, P405, P501
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 118 °C (244 °F; 391 K) (open cup)
415 °C (779 °F; 688 K)
Lethal dose or concentration (LD, LC):
2000 mg/kg (rat, oral)
1400 mg/kg (mouse, oral)
870 mg/kg (rabbit, oral)[4]
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 0.5 mg/m3 [skin][3]
REL (Recommended)
: Ca TWA 0.5 mg/m3 [skin][3]
IDLH (Immediate danger)
50 mg/m3[3]
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

o-Anisidine (2-anisidine) is an organic compound with the formula CH3OC6H4NH2. A colorless liquid, commercial samples can appear yellow owing to air oxidation. It is one of three isomers of the methoxy-containing aniline derivative.

Production and use[edit]

It is prepared via methanolysis of 2-chloronitrobenzene:[5]

NaOCH3 + ClC6H4NO2 → CH3OC6H4NO2 + NaCl

The resulting o-nitroanisole is reduced to o-anisidine.

o-Anisidine is used in the manufacture of dyes. It is nitrated to give 4-nitroanisidine. It is also a precursor to o-dianisidine.

One special use is as a heartwood indicator. An acid solution of o-anisidine is diazotized by adding a sodium nitrite solution. This mixture is applied to the wood and by reaction with polyphenols in the heartwood a reddish brown azo dye is formed.

Direct Blue 15 is an azo dye produced from o-anisidine.

Safety and environmental aspects[edit]

o-Anisidine is a dangerous pollutant from the production of dyes. It is listed as RCRA hazardous waste, with the code K181.[6] The International Agency for Research on Cancer (IARC) has classified o-anisidine as a Group 2B, possible human carcinogen.[7]


  1. ^ Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 669. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4. The names ‘toluidine’, ‘anisidine’, and ‘phenetidine’ for which o-, m-, and p- have been used to distinguish isomers, and ‘xylidine’ for which numerical locants, such as 2,3-, have been used, are no longer recommended, nor are the corresponding prefixes ‘toluidine’, ‘anisidino’, ‘phenetidine’, and ‘xylidino’. 
  2. ^ Weast, Robert C., ed. (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. C-98. ISBN 0-8493-0462-8. .
  3. ^ a b c d "NIOSH Pocket Guide to Chemical Hazards #0034". National Institute for Occupational Safety and Health (NIOSH). 
  4. ^ "o-Anisidine". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH). 
  5. ^ Gerald Booth "Nitro Compounds, Aromatic" Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a17_411
  6. ^ http://www.epa.gov/osw/hazard/wastetypes/wasteid/dyes/index.htm
  7. ^ https://pubchem.ncbi.nlm.nih.gov/compound/o-anisidine#section=Top

External links[edit]