Formic acid (E 236, methanoic acid) among the monobasic acids (saturated) is in the first place. Under normal conditions, the substance is a colorless liquid. The chemical formula of formic acid is HCOOH.
Along with its acidic characteristics, it also exhibits aldehyde qualities. This is due to the structure of the substance E236.
In nature, the substance is found in nettles, needles, fruits, caustic bees and secretions and in ants. Formic acid was first discovered and described in the 17th century. The substance got its name because it was found in ants.
Typically, the component is used as an antibacterial and preservative agent in the preparation of feed. The chemical properties of formic acid slow down the processes of decay and decay. That is why silage and hay treated with this substance last longer. The substance is also used in medicine. In dyeing wool (mordant), as a bleach in tanning of the skin, in combating beekeeping with parasites, formic acid is also used as a solvent in some reactions.
The chemical properties of the substance are manifested depending on the concentration. In accordance with the EU classification, with a quantitative composition of up to 10% it acts irritatingly, more than 10% - corrosive.
100% formic acid (liquid) in contact with the skin provokes very severe burns. The ingress of even a small amount in such a concentration on the cover causes severe pain. The affected area begins to turn white at first, as if covered with hoarfrost, then it becomes like wax. Around the burnt area a red border is formed. The acid is able to quickly penetrate the fatty layer of the skin, so it is necessary to immediately wash the affected area.
Concentrated vapors of the substance can cause damage to the respiratory tract and eyes. Accidentally ingested, even in a diluted form, methane acid causes severe gastroenteritis of a necrotic nature.
The body quickly processes and removes the substance. However, along with this, E236 and formaldehydes formed during methanol poisoning provoke lesions in the optic nerve, which leads to blindness.
Formic acid salts are called formates. Heating with concentrated sulfuric acid leads to the decomposition of E236 into H2O and CO, which is used to form carbon monoxide.
Under industrial conditions, formic acid is obtained from sodium hydroxide and carbon monoxide.
The boiling point of the substance is 100.7, freezing - 8.25 degrees.
Under indoor conditions, E236 decomposes into carbon monoxide and water. According to experimental evidence, methane acid is superior in strength to acetic acid. However, due to the ability of the former to rapidly decompose, it is used extremely rarely as a solvent.
It is believed that E236 is a very hygroscopic substance. During the experiments, it was found that obtaining an anhydrous drug using dehydrating reagents is not possible.
Contact formic acid with moist air is not allowed.
E236 with a purity of more than 99% can be obtained from an aqueous solution by applying a two-stage distillation using butyric acid. The first distillation eliminates the bulk of the water. The residue will contain approximately 77% substance. To drive it, apply 3-6 times the amount of butyric acid in the form of an azeotropic mixture.
In the process of opening the container with E236, special care must be taken. When storing formic acid over an extended period, significant pressure can form in the container.