Propionic acid, IMP

Propanoic acid (other names - methylacetic acid, E280 preservative, propionic acid) is liquid without color with caustic off - flavor. Has the following chemical formula: C2H5 - COOH.

Physical properties of propionic acid

1. Temperature of melting is equal - 21 °.

2. Temperature of boiling makes 141 °.

3. Temperature of flash is equal 54 °.

4. Molar mass is equal 74,08 grams/mol.

5. At reference conditions represents colorless liquid.

6. Self - ignition temperature is equal 440 °.

Chemical properties of propionic acid

1. Mixes up with water (H2O) and organic solvents.

2. Propanoic acid is typical representative of carboxylic saturated acids. Can form ethers, galogenagidrida, amides and other substances.

History of discovery of propanoic acid

This substance has been for the first time described in 1844 by Gottlieb Johan who has found it among sugar decomposition products. Then for some time other scientists - chemists received this acid in the different ways, without realizing at the same time that got the same connection. And in 1847 Jean - Baptiste Dumas has established that the substances received earlier were the same acid which he called afterwards as propanoic acid which formula - C2H5 - COOH.

What ways of receiving propanoic acid exist?

In the nature propanoic acid is found in oil.

The industry receives this substance by means of carbonylation of ethylene on Reppe reaction as by - product at oxidation of carbons, catalytic oxidation of propane aldehyde in the presence of ions of manganese or cobalt.

Also large amount of methylacetic acid can be received by production of acetic acid, however modern ways of receiving have made this way minor source of propanoic acid.

This substance can be received at metabolic decomposition of amino acids and fatty acids which contain odd number of carbon atoms.

Also propanoic acid is made by sort Propionibacterium bacteria (as finished product of the metabolism). These bacteria meet in gastrointestinal tract of ruminants, and because of their activity Swiss cheese has the unique aroma.

Derivatives of propanoic acid

1. These are ethers and salts.

2. Alkaline - earth and alkaline salts are well dissolved in water (H2O), not dissolved in organic solvents.

3. Ethers of this substance are badly soluble in (H2O) water, but mix up with organic solvents.

Use of propanoic acid

This acid is used in the following cases:

- production of herbicides (for example, dikhlorprol, propyl alcohol), medicines (fenobolin, ibuprofen), some fragrant substances (linaloil - , phenyl - geranyl - Benzylium - propionates), solvents (butyl - pentyl - propyl propionate), plastic (polyvinylpropionate), surfactant (glycol ethers) and vinylplasticizers;

- as propanoic acid interferes with growth of some bacteria and mold, its most part is used as preservative in food both for the person, and for animals. In products for animals directly propionic acid or its salt is used (ammonium propionate), and in products which are made for the person, it is used calcic (calcium propionate) or sodium (sodium propionate) or salts.

Safety during the work

The main danger during the work with propionic acid are chemical burns of varying severity.

In researches which were conducted on laboratory animals emergence yazvochek in gullet and stomach was the only negative effect connected with long - term consumption of small doses of propanoic acid that is caused by the corroding properties of substance. During experiment it was not revealed that propanoic acid of mutagen, is cancerogenic, toxic and badly influences reproductive organs. Getting to organism, the substance considered by us quickly is oxidized, metabolized and then removed in the form of carbon dioxide gas.