Acetic Acid

Products

Acetic acid is available as an aqueous solution in various concentrations in pharmacies and drugstores.

Structure and properties

Acetic acid (C2H4O2, Mr = 60.1 g/mol) or CH3-COOH is the simplest carboxylic acid after formic acid. It consists of a methyl and carboxyl group. It exists as a pure substance as a clear, volatile, colorless liquid and also as a crystalline mass due to its melting point of about 17°C and is miscible with water. Acetic acid has a pungent odor and is corrosive. Pharmacopoeias distinguish the following concentrations, among others (examples):

  • Acetic acid 99% (Acidum aceticum glaciale PhEur) – glacial acetic acid, anhydrous acetic acid.
  • Acetic acid 30% (Acidum aceticum 30 per centum PH) – Diluted acetic acid.

Its salts and esters are called acetates, for example, the excipient sodium acetate. Some active pharmaceutical ingredients are also in this form. The Latin name is derived from acetum (Latin for vinegar). Acetic acid is a natural substance that is formed, for example, after alcoholic fermentation from ethanol (alcohol) by bacterial oxidation. It is referred to as acetic acid fermentation or fermentation, which occurs in acetic acid bacteria (e.g. ). In vinegar, it is typically present in a concentration of at least 4.5% to 5%, although the acidity of the products varies. Ethanol + oxygen (O2) acetic acid + water (H2O) Acetic acid occurs as a metabolic product in all living things. With a pKa of 4.76, it is only a weak acid.

Effects

Acetic acid (ATC G01AD02, ATC S02AA10) has acidic, corrosive, irritant, preservative, and antimicrobial properties.

Fields of application

Numerous applications exist for acetic acid in suitable dilutions (selection):

  • As a disinfectant.
  • As a caustic, for warts and corns.
  • As a blood circulation stimulant.
  • For the production of active ingredient salts.
  • For chemical syntheses, as a reagent and solvent.
  • As an auxiliary for the adjustment of pH, as a buffer with sodium acetate.
  • In vinegar as food, for example, for the production of salad dressings, as a preservative, for vinegar preserves and mayonnaise.
  • As a cleaning agent, for descaling.

Adverse effects

The hazard potential of acetic acid depends on its concentration. Glacial acetic acid (99%) is corrosive and can cause burns to the skin, mucous membranes and eyes. It must also be noted that both the liquid and its vapors are flammable (!) Appropriate precautions must be observed. They can be found in the safety data sheet. Solutions with a lower concentration are not flammable, but are still irritant or corrosive.