Butyric

Butyric acid, also known as butanoic acid, is a short-chain carboxylic acid with four carbon atoms. It is a colorless to pale-yellow liquid at room temperature and has a strong, unpleasant odor often described as rancid butter. The acid is miscible with water in its low-temperature forms and forms esters and salts readily.

Chemical properties and nomenclature: Butyric acid is the simplest member of the butyric acid family and is often encountered in the ionized form as butyrate in biological contexts. Its chemical formula is C4H8O2, and it participates in typical carboxylic acid reactions such as esterification and amide formation.

Occurrence and production: Butyric acid occurs naturally in small amounts in dairy products and other fats, where it is released by lipolysis during spoilage. It is also produced endogenously in the mammalian gut by anaerobic fermentation of dietary fiber by microbial communities, yielding butyrate, a major energy source for colonocytes.

Biological role: In humans, butyrate is a key short-chain fatty acid that serves as an energy substrate for colon cells and influences gut health. It can act as an inhibitor of histone deacetylases, affecting gene expression, and engages receptors such as GPR41 and GPR43 to modulate inflammatory and metabolic pathways. Adequate butyrate production is associated with maintaining intestinal barrier integrity and may have protective effects in certain inflammatory conditions.

Industrial uses and derivatives: Butyric acid is used to synthesize esters, including fruity flavor compounds such as butyl butyrate, which contribute to flavor and fragrance applications. It serves as an intermediate in the production of various esters and serves as a precursor in some polymer and fragrance syntheses.

Safety: Butyric acid is corrosive and an irritant; it has a strong odor and can be irritating to the eyes, skin, and respiratory tract in concentrated form. It should be handled with appropriate controls.