Glycerol doesn't actually decompose at its boiling point. It's true that glycerol decomposes when heated to high temperatures, but this occurs above its boiling point.

Here's a breakdown:

* Boiling point of glycerol: Glycerol has a relatively high boiling point of 290 °C (554 °F). This is due to the strong hydrogen bonds between its hydroxyl groups.

* Decomposition: When glycerol is heated to temperatures above its boiling point, it undergoes thermal decomposition. This means that the glycerol molecules break down into smaller molecules, such as acrolein. This decomposition process is typically initiated at temperatures around 300 °C (572 °F) and above.

So, while glycerol can be safely boiled at its normal boiling point, prolonged exposure to temperatures exceeding its boiling point will lead to its decomposition.

Therefore, glycerol doesn't decompose at its boiling point, but rather at temperatures above its boiling point.