Which scenario typically requires vacuum distillation?

Vacuum distillation is primarily utilized for separating compounds that are sensitive or thermally unstable, which is why this scenario is the correct application. In this process, the pressure is reduced, which lowers the boiling points of the substances involved. This is particularly important for compounds that might decompose or react at higher temperatures, as it allows for distillation at lower temperatures, preserving the integrity of those compounds.

In scenarios where compounds are sensitive to thermal degradation, using vacuum distillation minimizes the risks associated with elevated temperatures, thus allowing for safe separation without the compromise of the chemical structures.

Other scenarios such as reactions with oxygen at high temperatures, closely boiling points requiring a more refined separation technique, or dealing with solid mixtures that require heating may not specifically necessitate the vacuum distillation technique, as they do not primarily focus on protecting the stability of thermally sensitive compounds in the same way.