Pharmaceutical companies commonly include propionic acid in the formulation of steroidal and nonsteroidal anti-inflammatory (NSAIDS) medications. In low doses, manufacturers use the acid as a preservative and as an antimicrobial agent in foods produced for human consumption. The manufacture of dyes, pharmaceutical compounds, agrochemicals, plastics and artificial flavors are other processes that make use of propanoic acid sometimes as well.
Consisits of three carbon molecules and is produced naturally by certain bacteria during fermentation, propionic acid is a saturated fatty acid. The compound may also be synthetically created using ethylene or natural gas. In their natural state, propionates are a colorless, oily liquid having a pungent odor. When used as a calcium or sodium salt, propionic acid may be colorless, white and crystallized, or in a powdered form that readily dissolves in water or alcohol.
propanoic acid is relatively acidic. That’s because of the structure of the functional group. When the -OH part of the carboxyl group gives up its hydrogen ion, the oxygen atom is left with a negative charge. This charge, however, is not stuck on this oxygen atom only; rather, it is delocalized over the two oxygen atoms.
Propanoic acid has the following molecular formula: C3H6O2. The three carbons form a chain; the carbon at the end of the chain has an oxygen atom double-bonded to it and an -OH group attached to it as well. This group of atoms or functional group is collectively called a carboxyl group, and compounds like propanoic acid are called carboxylic acids because they are relatively acidic. Acetic acid, also known as vinegar, is another example of a carboxylic acid.
Propanoic acid can be produced in different ways. For one, propanal can be oxidized to yield the carboxylic acid. Just like other carboxylic acids, it could be prepared by adding hot base or acid to propanenitrile followed by an acid-water workup, or by carbonating the Grignard reagent formed from magnesium and 1-bromopropane(C3H7Br, CAS No. 106-94-5). It can also be made from propanoic anhydride by hydrolysis or alcoholysis; the hydrolysis would form two molecules of the acid, while the alcoholysis would form an ester and the acid.
Researchers believe that propionic acid can also inhibit prostaglandin synthesis. Pharmaceutical companies commonly include it as an ingredient in NSAIDS. Aspirin, ibuprofen, and other over-the-counter and prescription anti-inflammatory preparations commonly contain propionic acid as an ester. The acidic properties of propionates provide antimicrobial activity against some bacteria. Propionic acid is more commonly used for fungal and mold growth prevention. Its acidic nature allows it to penetrate the cells of microorganisms, and after gaining entrance into the cytoplasm, the acid decreases the cellular pH.