Acetic acid is a weak and colorless organic acid. It is called glacial acetic acid in its undiluted state, glacial meaning water-free. It has a characteristic sour taste and pungent smell. Although it is weak, concentrated acid is highly corrosive. Dilute acetic acid is called vinegar, which is used in the food industry frequently.
This is one of the most widely used method for the production of acetic acid. In this process, methanol and carbon monoxide are the staring materials. A catalyst is required for the carbonylation process such as iodine, rhodium and iridium. The methanol reacts with iodine catalyst to form iodomethane which produces acetic acid with carbon monoxide.
CH3OH + HI --> CH3I + H2O
CH3I + CO --> CH3COI
CH3COI + H2O --> CH3COOH + HI
Acetic acid is also produced from acetaldehyde, which is produced by the oxidation of butane or hydration of ethane. In the presence of various metal catalysts, acetaldehyde oxidises to acetic acid.
2C4H10 + 5O2--> 4CH3COOH + 2H2O
Bacteria such as acetobacterium or clostridium convert sugars into ethanol, methanol or carbon monoxide and subsequently acetic acid in the absence of air.
C6H12O6 --> 3 CH3COOH
2 CO2 + 4 H2 --> CH3COOH + 2 H2O