Propionic acid
[CAS# 79-09-4]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Acyclic carboxylic acid
• Name: Propionic acid
• Synonyms: Propanoic acid
• Molecular Formula: C₃H₆O₂
• Molecular Weight: 74.08
• CAS Registry Number: 79-09-4
• EC Number: 201-176-3
• FEMA: 2924
• SMILES: CCC(=O)O

Properties

• Density: 0.9934
• Melting point: -22 °C
• Boiling point: 141 °C
• Refractive index: 1.385-1.387
• Flash point: 51 °C
• Water solubility: 37 g/100 mL

Safety Data

• Hazard Symbols: GHS02;GHS05;GHS07 Danger
• Risk Statements: H226-H314
• Safety Statements: P210-P233-P240-P241-P242-P243-P260-P264-P280-P301+P330+P331-P302+P361+P354-P303+P361+P353-P304+P340-P305+P354+P338-P316-P321-P363-P370+P378-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Flammable liquids	Flam. Liq.	3	H226
Serious eye damage	Eye Dam.	1	H318
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	3	H311
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Eye irritation	Eye Irrit.	2	H319
Skin corrosion	Skin Corr.	1C	H314
Specific target organ toxicity - single exposure	STOT SE	3	H336
Skin corrosion	Skin Corr.	1A	H314

• Transport Information: UN 1848; UN 2924

Discovery and Applications

Propionic acid, with the chemical formula C3H6O2, is a colorless liquid organic acid characterized by a distinctive pungent odor. Its discovery dates back to the early 19th century when it was first isolated from the fermentation of butter by the French chemist Henri Braconnot in 1844. The name "propionic" is derived from the Greek word "protos," meaning first, and "pion," meaning fat, reflecting its early identification in fatty substances.

Propionic acid is primarily produced through the fermentation of carbohydrates or the oxidation of propanol. Industrially, it is commonly synthesized by the carbonylation of ethylene or through the reaction of sodium carbonate with calcium propionate. The global production of propionic acid has significantly increased over the years due to its versatile applications across various industries.

One of the primary applications of propionic acid is as a preservative in the food industry. It effectively inhibits the growth of mold and other spoilage microorganisms, making it a valuable additive for baked goods, cheese, and other food products. It is generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA) and is widely used in both domestic and commercial food preservation.

In addition to its role as a preservative, propionic acid serves as a key intermediate in the production of various chemicals. It is used in the synthesis of propionates, which are important esters employed in the manufacturing of fragrances, flavorings, and pharmaceuticals. The acid is also utilized in the production of herbicides, where it acts as a precursor in synthesizing active ingredients.

Propionic acid has applications beyond the food and chemical industries. It is utilized in the agricultural sector as a feed additive to enhance the nutritional quality of livestock feed, promoting better growth and health in animals. Furthermore, it finds use in the production of biodegradable polymers and as a solvent in the pharmaceutical industry.

Despite its numerous applications, propionic acid should be handled with care due to its corrosive nature and potential health hazards. Prolonged exposure to the skin or inhalation of vapors can lead to irritation. Therefore, proper safety measures must be implemented when using this chemical in industrial settings.

In summary, propionic acid is a significant organic compound with a rich history of discovery and diverse applications. From its role as a food preservative to its importance in chemical synthesis, propionic acid continues to play a vital role in various industries, demonstrating its versatility and utility.

References

1998. Human Responses to Propionic Acid. I. Quantification of Within- and Between-participant Variation in Perception by Normosmics and Anosmics. Chemical Senses, 23(1).
DOI: 10.1093/chemse/23.1.71

1984. Inhibition of growth and patulin synthesis in Penicillium expansum by potassium sorbate and sodium propionate in culture. Applied and Environmental Microbiology, 48(5).
DOI: 10.1128/aem.48.5.1031-1033.1984

1984. Effect of acetate and octanoate on tricarboxylic acid cycle metabolite disposal during propionate oxidation in the perfused rat heart. Biochimica et Biophysica Acta (BBA) - General Subjects.
DOI: 10.1016/0304-4165(84)90149-1