Production
In industry, propanoic acid is mainly produced by the hydrocarboxylation of ethylene using nickel carbonyl as the catalyst:
- H2C=CH2 + H2O + CO → CH3CH2CO2H
It is also produced by the aerobic oxidation of propionaldehyde. In the presence of cobalt or manganese ions, this reaction proceeds rapidly at temperatures as mild as 40–50 °C:
- CH3CH2CHO + ½ O2 → CH3CH2COOH.
Large amounts of propanoic acid were once produced as a byproduct of acetic acid manufacture. Currently the world's largest producer of propanoic acid is BASF, with approximately 80 kt/a production capacity.
Propanoic acid is produced biologically as its coenzyme A ester, propionyl-CoA, from the metabolic breakdown of fatty acids containing odd numbers of carbon atoms, and also from the breakdown of some amino acids. Bacteria of the genus Propionibacterium produce propanoic acid as the end product of their anaerobic metabolism. This class of bacteria is commonly found in the stomachs of ruminants and the sweat glands of humans, and their activity is partially responsible for the odor of both Swiss cheese and sweat.
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Famous quotes containing the word production:
“The myth of unlimited production brings war in its train as inevitably as clouds announce a storm.”
—Albert Camus (1913–1960)
“The growing of food and the growing of children are both vital to the family’s survival.... Who would dare make the judgment that holding your youngest baby on your lap is less important than weeding a few more yards in the maize field? Yet this is the judgment our society makes constantly. Production of autos, canned soup, advertising copy is important. Housework—cleaning, feeding, and caring—is unimportant.”
—Debbie Taylor (20th century)
“I really know nothing more criminal, more mean, and more ridiculous than lying. It is the production either of malice, cowardice, or vanity; and generally misses of its aim in every one of these views; for lies are always detected, sooner or later.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)