7825. Propionic Acid

Nomenclature

CAS number: 79-09-4
Propanoic acid; methylacetic acid; ethylformic acid.
C3H6O2; mol wt 74.08.
C 48.64%, H 8.16%, O 43.19%.

Description and references

Occurs in dairy products in small amounts. Can be obtained from wood pulp waste liquor by a fermentation process using bacteria of the genus Propionibacterium: Wayman et al., US 3067107 (1962 to Columbia Cellulose). Prepn from ethylene, carbon monoxide and steam: Reppe, Angew. Chem. 1956, 46; Larson, US 2448375 (1948 to du Pont); from ethanol and carbon monoxide using a boron trifluoride catalyst: Loder, US 2135448; US 2135451; US 2135453 (all 1939 to du Pont); by oxidation of propionaldehyde: Hasche, US 2294984 (1942 to Kodak); from natural gas by the Fischer-Tropsch process; as a byproduct in the pyrolysis of wood; by the action of microorganisms on a variety of materials in small yields. Very pure propionic acid can be obtained from propionitrile. Toxicity study: H. F. Smyth et al., Am. Ind. Hyg. Assoc. J. 23, 95 (1962).

Chemical structure

Properties

Oily liquid. Slightly pungent, disagreeable, rancid odor. d420 0.99336. mp -21.5°. bp760 141.1°; bp400 122.0°; bp100 85.8°; bp1.0 4.6°. nD25 1.3848. Flash pt, open cup: 136°F (58°C). Viscosity (cP) at 15°: 1.175; at 25°: 1.020; at 30°: 0.956; at 60°: 0.668; at 90°: 0.495. Surface tension in dynes/cm at 15°: 27.21. Ka at 25°: 1.34 × 10-5. Corrosive. Misc with water. Can be salted out of water solns by the addn of CaCl2 or other salts. Sol in alcohol, ether, chloroform. Azeotrope with water, bp 99.98°, contains 17.7% acid; with toluene, bp 110.45°, contains 3% acid; with o-xylene, bp 135.4°, contains 43% acid; with ethylbenzene, bp 131.1°, contains 28% acid. LD50 orally in rats: 4.29 g/kg (Smyth).

Derivative

Barium salt monohydrate.

Nomenclature

CAS number: 5915-88-8
Barium propionate.
C6H10BaO4.H2O; mol wt 301.48.
C 23.90%, H 4.01%, Ba 45.55%, O 26.53%.

Properties

Powder, usually with slight odor. Poisonous. Freely sol in water; slightly sol in alcohol.

Caution

Potential symptoms of overexposure to propionic acid are irritation of eyes, skin, nose, throat; blurred vision, corneal burns; skin burns; abdominal pain, nausea, vomiting. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 266.

Use

Esterifying agent; in the production of cellulose propionate (thermoplastic) and other propionates, e.g., calcium propionate, used as mold inhibitors and preservatives; in the manuf of ester solvents, fruit flavors, and perfume bases.

Therapeutic Category

Antifungal.

Keywords

Antifungal (Synthetic)