Ethanoic acid (another name is acetic acid) is an organic substance, which is an extremely basic, weak, carboxylic acid. Derivatives of this acid are called acetates. Using this substance, you can get ethanoic acid methyl ester: ethanal + ethanoic acid = methyl ether.
Physical properties of ethanoic acid
1. Ethanoic acid (formula - CH3COOH) is a colorless liquid with a specific odor and an unpleasant sour taste.
2. Hygroscopic. It is infinitely soluble in water.
3. Ethanoic acid is miscible with most solvents. Inorganic gases and compounds, such as HI (hydrogen iodide), HF (hydrogen fluoride), HBr (hydrogen bromide), HCl
(hydrochloric acid), and many others dissolve well in it.
4. Exists in the form of linear and cyclic dimers.
5. The
dielectric constant is 6.1.
6. The autoignition temperature in air is 454 degrees.
7. Ethanoic acid forms azeotropic mixtures with carbon tetrachloride, benzene, cyclohexane, toluene, heptane, ethylbenzene, trichlorethylene, o-xylene, p-xylene and bromophore.
Ethanoic acid can be obtained in several ways:
1. By
oxidizing acetaldehyde with oxygen from the air. This process is possible only in the presence of a catalyst - manganese acetate at a temperature of 50 to 60 degrees. The reaction looks like this:
2CH3CHO (acetaldehyde) + O2 (oxygen) = 2CH3COOH (ethanoic acid)
2. The industry uses oxidative methods. Previously, the oxidation of butane and acetaldehyde was used to produce ethanoic acid.
Acetylaldehyde was oxidized only in the presence of manganese acetate at elevated pressure and temperature. The yield of ethanoic acid was about ninety-five percent.
2CH3CHO + O2 = 2CH3COOH
N-butane was oxidized at a temperature of 150 to 200 degrees. In this case, cobalt acetate served as a catalyst.
2C4H10 + 5O2 = 4CH3COOH + 2H2O
But as a result of a significant increase in oil prices, both of these methods became unprofitable and were soon replaced by more efficient methanol carbonylation methods.
3. Catalytic methanol carbonylation is an important method for the synthesis of ethanoic acid. Occurs according to the conditional equation:
CH3OH + CO = CH3COOH
4. There is also a biochemical production method in which the ability of microorganisms to oxidize ethanol is used. This process is called acetic fermentation. At the same time, aqueous ether of ethyl alcohol or ethanol-containing liquids (fermented juices) are used as raw materials. This is a multi-stage complex process. It can be described by the following equation:
CH3CH2OH (alcohol ether) + O2 (oxygen) = CH3COOH (ethanoic acid) + H2O
Application
- aqueous solutions of ethanoic acid are used in the food industry, cooking and in canning;
- ethanoic acid is used to create aromatic substances and medicines (acetone, cellulose acetate);
- used in dyeing and typography;
- as a reaction medium for the oxidation of certain organic substances (oxidation of sulfides by hydrogen peroxide);
- since the fumes of ethanoic acid have an unpleasant pungent odor, it can be used instead of ammonia.