heptanoic

Heptanoic acid, also known as enanthic acid, is a saturated straight-chain carboxylic acid with seven carbon atoms. Its chemical formula is C7H14O2 and its structure consists of a carboxyl group at one end of a seven-carbon alkyl chain.

At room temperature it is typically a colorless liquid with the characteristic odor common to fatty acids. It has limited solubility in water but dissolves in many organic solvents. The carboxyl group gives heptanoic acid its acidic behavior, with a pKa around 4.8, and it readily forms salts such as sodium heptanoate in basic solutions.

Industrial production of heptanoic acid is usually by oxidation of the corresponding aldehyde (heptanal) or by oxidation of heptanol. It can also be prepared by hydrolysis of derivatives such as heptanoyl chloride or esters derived from heptanoic acid. In nature, it can occur in trace amounts in fats and oils, but it is primarily obtained synthetically for industrial use.

Applications of heptanoic acid include the production of esters for flavors and fragrances, where it forms alkyl heptanoates with alcohols. It serves as an intermediate in organic synthesis, including the preparation of acyl chlorides and various pharmaceutical and polymer products. In medicine, esters derived from heptanoic acid, such as testosterone enanthate, are used as long-acting pharmaceutical agents.

Safety notes: heptanoic acid is an irritant to skin and eyes and should be handled with appropriate protective equipment. It should be stored away from oxidizers and handled in well-ventilated areas. Etymology: the name derives from Greek enanth- meaning seven, combined with the -oic acid suffix.