Everything about Propionic Acid totally explained
| Section2 =
| Section3 =
| Section7 =
| SPhrases =,,,
}}
| Section8 =
}}
Propionic acid (systematically named
propanoic acid) is a naturally-occurring
carboxylic acid with
chemical formula CH3CH
2C
OOH. In the pure state, it's a colorless, corrosive liquid with a pungent odor. The
anion CH
3CH
2COO
− as well as the
salts and
esters of propionic acid are known as
propionates (or propanoates).
History
Propionic acid was first described in
1844 by
Johann Gottlieb, who found it among the degradation products of
sugar. Over the next few years, other chemists produced propionic acid in various other ways, none of them realizing they were producing the same substance. In
1847, the French chemist
Jean-Baptiste Dumas established that all the acids were the same compound, which he called propionic acid, from the
Greek words
protos = "first" and
pion = "fat," because it was the smallest H(CH
2)
nCOOH acid that exhibited the properties of the other
fatty acids, such as producing an oily layer when salted out of water and having a
soapy
potassium salt.
Properties
Propionic acid has physical properties intermediate between those of the smaller carboxylic acids,
formic and
acetic acid, and the larger
fatty acids. It is miscible with water, but it can be removed from water by adding salt. As with acetic and formic acids, its vapor grossly violates the
ideal gas law because it doesn't consist of individual propionic acid molecules, but instead of
hydrogen bonded pairs of molecules. It also undergoes this pairing in the liquid state.
Propionic acid displays the general properties of carboxylic acids, and, like most other carboxylic acids, it can form
amide,
ester,
anhydride, and
chloride derivatives. It can undergo alpha-
halogenation with
bromine in the presence of
PBr3 as
catalyst (the
HVZ reaction) to form CH
3CHBrCOOH.
Production
In industry, propionic acid is main produced by the hydrocarboxylation of
ethylene using
nickel carbonyl as the catalyst:
» RCH=CH
2 + H
2O + CO → CH
3CH
2CO
2H
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 → CH
3CH
2COOH
Large amounts of propionic acid were once produced as a byproduct of acetic acid manufacture. Current world's largest producer is
BASF, with approximately 80 ktpa production capacity.
Propionic 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 it the breakdown of some
amino acids.
Bacteria of the genus
Propionibacterium produce propionic 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.
Uses
Propionic acid inhibits the growth of
mold and some
bacteria. As a result, most propionic acid produced is used as a
preservative for both animal feed and food for human consumption, and can be used as a preservative for Ballistics Gel. For animal feed, it's used either directly or as its
ammonium salt. In human foods, especially
bread and other baked goods, it's used as its
sodium or
calcium salt. Similar usage occurs in some of the older anti-fungal foot powders.
Propionic acid is also useful as a chemical intermediate. It can be used to modify synthetic
cellulose fibers. It is also used to make
pesticides and
pharmaceuticals. The
esters of propionic acid are sometimes used as
solvents or artificial flavorings.
Safety
The chief danger from propionic acid is chemical burns that can result from contact with the concentrated liquid. In studies on laboratory animals, the only adverse health effect associated with long-term exposure to small amounts of propionic acid has been
ulceration of the
esophagus and
stomach from consuming a corrosive substance. No toxic,
mutagenic,
carcinogenic, or reproductive effects have ever been observed. In the body, propionic acid is readily metabolized, so it doesn't bioaccumulate.
A recent publication by MacFabe and colleagues found that intraventricular infusions of propionic acid produced reversible behavior that was very similar to that seen in
autism. Behaviors included: hyperactivity, dystonia, turning, retropulsion. In addition, the treated rats demonstrated caudate spiking and the progressive development of limbic kindled seizures. The paper concludes that this is an excellent animal model of autism and warrants further study.
Human occurrence
The human
skin is host to a species of bacteria known as
Propionibacterium acnes, which is named after its ability to produce propionic acid. This bacteria lives mainly in the
sebaceous glands of the skin and is one of the principle causes of
acne.
Further Information
Get more info on 'Propionic Acid'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://propionic_acid.totallyexplained.com">Propionic acid Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
