P-Anisic acid explained

p-Anisic acid, also known as 4-methoxybenzoic acid or draconic acid, is one of the isomers of anisic acid. The term "anisic acid" often refers to this form specifically. It is a white crystalline solid which is insoluble in water, highly soluble in alcohols, and soluble in ether and ethyl acetate.

Synthesis and occurrence

p-Anisic acid is found naturally in anise. It was first synthesized in 1841 by Auguste Cahours by oxidizing anethole he purified from the anise essence by recrystallization with diluted nitric acid:^{[1] [2]}

CH3CH=CHC6H4OCH3 + HNO3 -> CH3OC6H4CHO + other CH3OC6H4CHO + HNO3 -> CH3OC6H4COOH + other

Oxidation of anisaldehyde, which was Cahours' intermediate product, is still used nowadays.^[3] Anisic acid can also be obtained synthetically by the oxidation of p-methoxyacetophenone.

Uses

p-Anisic acid has antiseptic properties.^[4] It is also used as an intermediate in the preparation of more complex organic compounds.

Notes and References

1. Wisniak . Jaime . 2013-10-01 . Auguste André Thomas Cahours . Educación Química . 24 . 4 . 451–460 . 10.1016/S0187-893X(13)72500-X . 0187-893X. free .
2. Book: Crochard (París) . Annales de chimie et de physique . Arago . François . Gay-Lussac . Joseph Louis . 1841 . Chez Crochard . fr.
3. 10.1016/j.ces.2013.05.043 . Kinetics of micellar catalysis on oxidation of p-anisaldehyde to p-anisic acid in aqueous medium at room temperature . 2013 . Saha . Rumpa . Ghosh . Aniruddha . Saha . Bidyut . Chemical Engineering Science . 99 . 23–27 . 2013ChEnS..99...23S .
4. 10.1007/s00284-018-1492-2 . Antimicrobial Ingredients as Preservative Booster and Components of Self-Preserving Cosmetic Products . 2019 . Herman . Anna . Current Microbiology . 76 . 6 . 744–754 . 29651551 .