What is the process of forming ethanoic acid?

Ethanoic acid is formed through the oxidation of ethanol using an oxidising agent such as acidified potassium dichromate (VI).

In more detail, ethanoic acid, also known as acetic acid, is the main component of vinegar and is a carboxylic acid. It is produced industrially by the oxidation of ethanol. This process involves the use of an oxidising agent, typically acidified potassium dichromate (VI) solution, in the presence of dilute sulphuric acid. The reaction is carried out under reflux, which means the reaction mixture is heated to boiling and the vapours are condensed and returned to the flask.

The chemical equation for this reaction is: CH3CH2OH + [O] → CH3COOH + H2O. Here, [O] represents the oxygen from the oxidising agent. The ethanol is oxidised to ethanoic acid, and water is also produced in the reaction.

The colour change during the reaction is also significant. The orange dichromate ion (Cr2O7^2-) is reduced to the green chromium (III) ion (Cr^3+), indicating that the reaction has taken place. This colour change from orange to green is a positive test for the presence of a primary alcohol, such as ethanol, being oxidised.

It's important to note that the reaction needs to be carefully controlled. If the temperature is too high, further oxidation can occur, leading to the formation of carbon dioxide and water instead of ethanoic acid. Therefore, the reaction is usually carried out at a gentle boil to ensure the correct product is formed.

In summary, the formation of ethanoic acid from ethanol is a key reaction in organic chemistry, demonstrating the process of oxidation and the use of an oxidising agent. It's a practical example of how everyday substances like vinegar are produced.