Phenol

Friedlieb Ferdinand Runge, 1834

Phenol (from phainomai Greek = shine - the name refers to the shining gas that was produced in addition to coal tar during the production of coke) is an aromatic, organic compound. Phenol consists of a phenyl group (C6H5) with a hydroxy group (see structural formula). Phenol forms salts with bases, the group of substances of phenolates.

At room temperature, pure phenol forms colourless to slightly pink crystals with a characteristic, aromatic odour. The melting point is 41 °C and the boiling point is 182 °C. Phenol is easily soluble in 96% ethanol, in ether and fatty oils. It is soluble in glycerol and water. The phenol dissolved in water is called Phenolum liquefactum .

Occurrence: Phenol is found in coal tar (s. Pix lithanthracis) and in various types of oil. Petroleum oils.

Phenol in chemistry: Phenol is mainly used as raw material for the production of plastics. Together with formaldehyde it is used for the production of different types of plastics. synthetic resins.

Phenol in food: The EFSA (European Food Safety Authority) has evaluated phenol and phenolic compounds in its "Risk Assessment Report". It has classified the estimated exposure of 0.15ug/kgkgKG/day via food as safe.

Phenol in microbiology: Phenol has bacteriostatic to bactericidal and fungicidal effects on some microorganisms depending on the concentration. In the 19th century it was therefore used as an antiseptic (known as carbolic) in the disinfection of skin and wounds. Because of the health risks, its use on humans for these purposes is obsolete.

Phenol in medicine: Phenol is the starting product for salicylic acid and the drug acetylsalicylic acid. Phenol is suspected to be mutagenic. Depending on its concentration, it has a bacteriostatic to bactericidal and fungicidal effect. In the 19th century it was therefore used as an antiseptic in the disinfection of skin and wounds. In low concentrations (0.2-0.5%) phenol is a common preservative in injection solutions, vaccines and desensitizing solutions for subcutaneous allergy immunotherapy (SCID).

Within the scope of the approvals for these therapeutics, the Paul-Ehrlich-Institut as the authorizing federal authority has assessed and approved phenol as a preservative. According to the current state of knowledge, the Institute assumes that there are no indications of a damaging effect of phenol in the approved concentrations. So far, it has not been possible to replace phenol by other substances. SCIT products contain 0.5% phenol in saline solution. In one injection about 2.0- 2.5 mg are injected.

Toxicity of phenol: Phenol is a protoplasmic poison. When concentrated, it kills all living cells. Phenol is absorbed through the skin; inhalation or oral absorption is also possible. In in vitro studies, a percutaneous absorption of 19% has been found for a local application. In the human organism, phenol is mainly conjugated with sulphate or glucuronic acid and excreted in urine.

Phenol is highly toxic both locally and systemically; at dermal exposure it has a toxic to corrosive effect on mucous membranes, skin and eyes. Prolonged skin contact leads to necrosis. (Therapy: immediate washing of the skin with soft soap, followed by application of a glucocorticoid externus).

Acute damage: The absorption of large quantities leads to massive kidney dysfunction within a few hours, up to acute kidney failure. Oral uptake causes burns in the mouth, throat, oesophagus and stomach; swallowing and gastrointestinal disorders may also occur.

Chronic damage: In chronic exposure, gastrointestinal and nervous disorders are also known. Inhalation may also cause symptoms of poisoning with dizziness, headache and disorders of the ears, vomiting, insomnia and kidney irritation.