o-Anisidine

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.

o-Anisidine
Skeletal formula of o-anisidine
Ball-and-stick model of the o-anisidine molecule
Names
Preferred IUPAC name
2-Methoxyaniline[1]
Other names
ortho-Anisidine
2-Anisidine
ortho-Aminoanisole
o-Methoxyaniline
2-Methoxy-1-aminobenzene
2-Methoxyphenylamine
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.001.785
EC Number
  • 201-963-1
KEGG
RTECS number
  • BZ5410000
UNII
UN number 2431
Properties[2]
C7H9NO
Molar mass 123.155 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
Hazards
Main hazards potential occupational carcinogen[3]
GHS pictograms
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 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
2
0
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]
NIOSH (US health exposure limits):
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
m-Anisidine
p-Anisidine
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Production and use

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

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]

References

  1. Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 669. doi:10.1039/9781849733069-00648. 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. 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 (2007). "Nitro Compounds, Aromatic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a17_411. ISBN 978-3527306732.
  6. "Hazardous Waste". 2015-07-23.
  7. "o-Anisidine".
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