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para-Anisidine (p-anisidine) is an organic compound with the formula CH3OC6H4NH2. A white solid, commercial samples can appear grey-brown owing to air oxidation. It is one of three isomers of anisidine, methoxy-containing anilines. It is prepared by reduction of 4-nitroanisole.[5]

Skeletal formula of p-anisidine
Ball-and-stick model of p-anisidine
Preferred IUPAC name
Other names
p-Anisidine (no longer recommended by IUPAC[1]); Phenetidine (no longer recommended by IUPAC[1])
3D model (JSmol)
ECHA InfoCard 100.002.959
EC Number 203-254-2
RTECS number BZ5450000
UN number 2431
Molar mass 123.15 g/mol
Density 1.071 (57 °C)
Melting point 56 to 59 °C (133 to 138 °F; 329 to 332 K)
Boiling point 243 °C (469 °F; 516 K)
Solubility soluble in ethanol, diethyl ether, acetone, benzene
Vapor pressure 0.006 mmHg (25 °C)[2]
-80.56·10−6 cm3/mol
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)The environment pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word Warning
H300, H310, H330, H350, H373, H400
P201, P202, P260, P262, P264, P270, P271, P273, P280, P281, P284, P301+310, P302+350, P304+340, P308+313, P310, P314, P320, P321, P322, P330, P361, P363, P391, P403+233
Flash point 122 °C (252 °F; 395 K)
515 °C (959 °F; 788 K)
Lethal dose or concentration (LD, LC):
2900 mg/kg (rabbit, oral)
1300 mg/kg (mouse, oral)
1400 mg/kg (rat, oral)[4]
1000 mg/kg (mouse, oral)[4]
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 0.5 mg/m3 [skin][2]
REL (Recommended)
TWA 0.5 mg/m3 [skin][2]
IDLH (Immediate danger)
50 mg/m3[2]
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


Anisidine valueEdit

p-Anisidine condenses readily with aldehydes and ketones to form Schiff bases, which absorb at 350 nm. This colorimetric reaction is used to test for the presence of oxidation products in fats and oils, an official method for detecting them by the American Oil Chemists' Society.[6] It is particularly good at detecting unsaturated aldehydes, which are the ones that are most likely to generate unacceptable flavors, making it particularly useful in food quality testing.[7][8]


p-Anisidine is a relatively toxic compound with a TWA of 0.5 mg/m3.[9]


  1. ^ a b 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. ^ a b c d "NIOSH Pocket Guide to Chemical Hazards #0035". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ 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..
  4. ^ a b "p-Anisidine". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  5. ^ Mitchell, Stephen C.; Waring, Rosemary H. (2000). "Aminophenols". Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. doi:10.1002/14356007.a02_099.
  6. ^ "AOCS Official Method Cd 18-90". American Oil Chemists' Society. Retrieved 26 February 2013.
  7. ^ Steele, Robert (2004). Understanding and Measuring the Shelf-Life of Food. Woodhead Publishing in Food Science and Technology Series. Woodhead Publishing. p. 136. ISBN 1855737329.
  8. ^ A.J. Dijkstra (2016). "Vegetable Oils: Composition and Analysis". Encyclopedia of Food and Health. pp. 357–364. doi:10.1016/B978-0-12-384947-2.00708-X.
  9. ^ "Occupational Safety and Health Guideline for Anisidine (o-, p-isomers)" (PDF).

External linksEdit