''p''-Anisidine (or ''para''-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 Anisidine can refer to any of the three possible isomers of methoxyaniline: * ''o''-Anisidine (2-methoxyaniline) * ''m''-Anisidine (3-methoxyaniline) * ''p''-Anisidine (4-methoxyaniline), used in measuring anisidine value {{chemistry index ...

methoxy In organic chemistry, a methoxy group is the functional group consisting of a methyl group bound to oxygen. This alkoxy group has the formula . On a benzene ring, the Hammett equation classifies a methoxy substituent at the ''para'' position as ...

-containing

aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine In organic chemistry, an aromatic amine is an organic compound consisting of an aroma ...

s. It is prepared by reduction of 4-nitroanisole.

Anisidine value

''p''-Anisidine condenses readily with

aldehydes In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group ...

and

ketones In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bon ...

to form

Schiff base In organic chemistry, a Schiff base (named after Hugo Schiff) is a compound with the general structure ( = alkyl or aryl, but not hydrogen). They can be considered a sub-class of imines, being either secondary ketimines or secondary aldimine ...

s, 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 The American Oil Chemists' Society (AOCS) is an international professional organization based in Urbana, Illinois dedicated to providing the support network for those involved with the science and technology related to fats, oils, surfactants, an ...

. 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.

Safety

''p''-Anisidine is a relatively toxic compound with a

permissible exposure limit The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits are established by the Occupational S ...

of 0.5 mg/m³.

References

External links

* * {{DEFAULTSORT:Anisidine, p- Anilines Hazardous air pollutants IARC Group 3 carcinogens