3Hydroxybenzoic

3-Hydroxybenzoic acid, commonly known as m-hydroxybenzoic acid, is a hydroxybenzoic acid in which a hydroxyl group is attached to the meta position relative to the carboxyl group on a benzene ring. Its molecular formula is C7H6O3, and it appears as a white to off-white crystalline solid. It is a weak acid and forms soluble salts with bases; it is sparingly soluble in water but more soluble in alkaline solutions.

The compound occurs in nature in small amounts in certain plants and is produced commercially as the free acid and as esters such as methyl 3-hydroxybenzoate. Industrial production typically involves transformations of related benzoate derivatives or the hydrolysis and subsequent functionalization of esters and chlorine- or bromine-substituted intermediates to install the meta-hydroxy group.

In organic synthesis, 3-hydroxybenzoic acid serves as an intermediate for the preparation of esters, amides, and heterocyclic compounds. It is used as a building block in the manufacture of dyes, fragrances, and various pharmaceutical agents, often enabling further functionalization at the carboxyl or phenolic sites.

Safety and handling: 3-Hydroxybenzoic acid is of relatively low to moderate acute toxicity and can irritate the skin, eyes, and respiratory tract with improper handling. Standard laboratory precautions apply: use appropriate personal protective equipment, work in a well-ventilated area, and avoid inhalation of dust. Store away from strong oxidizers and moisture.

See also: other hydroxybenzoic acids such as 2-hydroxybenzoic acid (salicylic acid) and 4-hydroxybenzoic acid.