Questions: (a) Dioxane has a boiling point of 101°C. Could you separate dioxane from methylcyclohexane by distillation? Explain why or why not, based on the liquid and vapor compositions during the distillation. (b) How might these liquids be separated?

Solution Steps

To determine if dioxane can be separated from methylcyclohexane by distillation, we first need to consider their boiling points. Dioxane has a boiling point of \(101^{\circ} \mathrm{C}\). Methylcyclohexane has a boiling point of approximately \(101^{\circ} \mathrm{C}\) as well. The closeness of these boiling points suggests that simple distillation may not effectively separate the two compounds.

In distillation, separation is based on differences in boiling points, which affect the liquid and vapor compositions. When two substances have very similar boiling points, their vapor compositions during distillation will also be similar, making it difficult to achieve separation. This is because the vapor phase will contain a significant amount of both components, leading to poor separation efficiency.

Given the similar boiling points, simple distillation is unlikely to be effective. Instead, azeotropic or fractional distillation might be considered, but even these methods may struggle due to the close boiling points. Other separation techniques, such as liquid-liquid extraction or the use of a separating agent, might be more effective. These methods rely on differences in solubility or chemical reactivity rather than boiling points.

Final Answer