Peroxyacetic acid
Structural formula | ||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
General | ||||||||||||||||
Surname | Peroxyacetic acid | |||||||||||||||
other names |
|
|||||||||||||||
Molecular formula | C 2 H 4 O 3 | |||||||||||||||
Brief description |
colorless, pungent smelling liquid |
|||||||||||||||
External identifiers / databases | ||||||||||||||||
|
||||||||||||||||
properties | ||||||||||||||||
Molar mass | 76.05 g mol −1 | |||||||||||||||
Physical state |
liquid |
|||||||||||||||
density |
1.226 g cm −3 (25 ° C) |
|||||||||||||||
Melting point |
0.1 ° C |
|||||||||||||||
boiling point |
from 40 ° C decomposition, from 100 ° C risk of explosion |
|||||||||||||||
Vapor pressure |
2055 Pa (25 ° C) |
|||||||||||||||
solubility |
|
|||||||||||||||
safety instructions | ||||||||||||||||
|
||||||||||||||||
Toxicological data | ||||||||||||||||
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
The peroxyacetic acid (abbr .: PES) is a colorless, pungent liquid which is chemically different from the acetic acid is derived and the peroxycarboxylic acids (and thus to the peroxides is one). In higher concentrations, peroxyacetic acid can decompose explosively.
history
Peroxyacetic acid was known shortly after hydrogen peroxide could be produced in the laboratory. Due to their sensitivity to traces of metal, however, it was not until 1930 that they learned to use them industrially. Nevertheless, many accidents happened and it could not prevail until plastic containers for transport and storage were available from 1960. Then different applications were discovered in the individual countries that justified larger production quantities.
- In the GDR it was promoted for political reasons in order to be prepared against a bacteriological attack from the West. As long as this did not come, the daily produced amount had to be sold. Animal stall disinfection was found to be the ideal area of application for large quantities.
- In England , many communities near the sea were reluctant to build a sewage treatment plant. So you disinfected the sewage with PES and then simply pumped the feces into the sea.
- In Austria , PES replaced the formalin that had been used to disinfect the leaching plant in sugar factories .
- In Italy there were modern sewage treatment plants , but due to the high temperatures they could not meet the sewage standards. The treated wastewater was then disinfected with PES.
Extraction and presentation
Peroxyacetic acid is made by mixing acetic acid with hydrogen peroxide . An equilibrium mixture of peroxyacetic acid, acetic acid, hydrogen peroxide and water is formed.
The establishment of equilibrium is accelerated by strong acids ( sulfuric acid ). Since the dilution of a peroxyacetic acid solution automatically leads to the establishment of a new equilibrium with a lower peroxyacetic acid content, the storage of diluted residues does not make sense.
Equilibrium peroxyacetic acid is commercially available in concentrations between 2.5% and 40%. An alternative is the vacuum distillation of the peroxyacetic acid from an equilibrium mixture. Because of the proximity of the boiling points, 38% to 40% peroxyacetic acid is obtained together with water. This mixture is not stable and must be kept at a temperature of 0 ° C for storage and transport. It is used for TCF (total chlorine-free) bleaching of sulphate pulp .
Technically, PES can be produced by the oxidation of acetaldehyde .
properties
When heated, peroxyacetic acid decomposes explosively. The compound has a strong oxidizing effect due to its hydroperoxide group . Due to its alkyl group, PES is slightly more fat-soluble ( lipophilic ) than hydrogen peroxide. It is a weaker acid than acetic acid, its salts can be isolated.
According to August, the vapor pressure function results according to lg (P) = −A / T + B (P in Torr, T in K) with A = 2311 and B = 8.911 in the temperature range from 0 ° C to 110 ° C.
Peracetic acid, when dissolved in acetic acid or ethyl acetate , forms detonable mixtures. This property is concentration and temperature dependent.
Detonation ability of peracetic acid in acetic acid . | ||||||||||||
concentration | in% | 20th | 30th | 40 | 45 | 50 | 54 | 57 | ||||
temperature | in ° C | 112 | 97 | 81 | 70 | 58 | 40 | 20th |
use
The strong oxidizing power due to use as a bleaching agent , inter alia, in paper , textiles and strength and as a disinfectant (in about one percent concentration) and sterilizing agent (eg. As in the cold aseptic filling of beverages in plastic bottles made of PET or HDPE ). As a chemical oxidizing agent, peroxyacetic acid is also used for the epoxidation of alkenes .
safety instructions
In humans and animals, peroxyacetic acid is very irritating to the skin and eyes.
PES decomposes in a self-accelerating manner and is particularly sensitive to external heating and contamination. The exothermic decomposition leads to the heating of the liquid, which can lead to boiling and deflagration. The risk increases sharply with the concentration and the container size. The concentration of technically used solutions is therefore usually limited to below 15%.
Individual evidence
- ↑ a b c d e f g h i Entry on peroxyacetic acid in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
- ↑ a b A. C. Egerton, W. Emte, GJ Minkoff: Some properties of organic peroxides. In: Discuss. Faraday Soc. 10, 1951, pp. 278-282. doi: 10.1039 / DF9511000278
- ↑ Entry on peroxyacetic acid. In: Römpp Online . Georg Thieme Verlag, accessed on November 11, 2014.
- ↑ Entry on Peracetic acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
- ↑ a b B. Phillips, PS Starcher, BD Ash: Preparation of Aliphatic Peroxyacids. In: J. Org. Chem. 23, 1958, pp. 1823-1826. doi: 10.1021 / jo01106a001