propane acid (other names - metiluksusnaya acid, preservative E280, propionic acid) - a colorless liquid with a pungent unpleasant odor.It has the following chemical formula: C2H5-COOH.
physical properties of propionic acid:
1. The melting point is -21 °.
2. Boiling point is 141 °.
3. The flashpoint is 54 °.
4. The molar mass is 74.08 g / mol.
5. Under normal conditions is a colorless liquid.
6. Auto-ignition temperature is 440 °.
chemical properties of propionic acid:
1. It can be mixed with water (H2O) and organic solvents.
2. propanoic acid - a typical representative of saturated carboxylic acids.May form esters galogenagidridy, amides, and other substances.
History of discovery propanoate
This substance was first described in 1844 by Johann Gottlieb, who found him among the decomposition products of sugar.Then, during a time other chemists this acid was prepared in different ways, without realizing it, it was extracted at the same compound.And in 1847, Jean-Baptiste Dumas found that previously obtained material was the same acid, which he later described as the propanoic acid, the formula of which - C2H5-COOH.
What are the methods of obtaining propane acid?
propanoic acid in nature is found in the oil.
In industry this substance is prepared by the carbonylation of ethylene Reppe reaction as a byproduct in the oxidation of hydrocarbons by catalytic oxidation of propane aldehyde in the presence of manganese ions or cobalt.
also a large number of metiluksusnoy acid can be obtained in the production of acetic acid, but modern methods of obtaining made this way to a secondary source of propanoic acid.
This substance can be prepared in the metabolic decomposition of amino acids and fatty acids which contain an odd number of carbon atoms.
also propanoic acid producing bacteria of the genus Propionibacterium (as the end product of their metabolism).These bacteria are found in the digestive system of ruminants, and it was because of their activity in the Swiss cheese has a unique flavor.
propionic acid derivatives
It esters and salts.
alkali and alkaline earth salts are readily soluble in water (H2O), do not dissolve in organic solvents.
Esters of this substance poorly soluble in (H2O) water but miscible with organic solvents.
Application
This acid is used in the following cases:
- production of herbicides (such as dihlorprol, propanol), drugs (fenobolin, ibuprofen), some fragrances (linaloil-, phenyl, geranil-, benzylpropionates), solvents (butyl, pentyl, propyl propionate), plastics (polivinilpropionat), surfactants (glycol ethers) and vinilplastifikatorov;
- since propanoic acid prevents the growth of certain bacteria and mold, most of it is used as a preservative in foods for both humans and animals.The product is used directly for animal propionic acid or its salt (ammonium propionate), and in products which are manufactured for the person using calcium (calcium propionate) or sodium (sodium propionate) or a salt thereof.
Safety at work
main danger when working with propionic acid - a chemical burns of varying severity.
In studies conducted on laboratory animals, the only negative effect associated with long-term intake of small doses of propionic acid, was the appearance of sores in the esophagus and the stomach, due to corrosive properties of the substance.During the experiment, it was discovered that the propanoic acid mutagenic, carcinogenic, toxic and bad for the reproductive organs.Once in the body, we are considering the substance oxidizes rapidly metabolized and then excreted in the form of carbon dioxide.
