Synthesis of Aniline: Understanding Separation and Purification Techniques
1. Why is extraction considered a separation technique and not a purification technique? 2. Why is simple distillation referred to as a purification technique? 3. Explain why it is important to switch the receiving flask after 100 ∘ C and not at a lower temperature? 4. During the extraction step the procedure requires a gentle inverting of the separatory funnel, why?
Extraction as a Separation Technique
Simple Distillation for Purification
Simple distillation is known as a purification technique because it separates components based on their boiling points. As the mixture is heated, the substance with the lower boiling point evaporates first and is collected as the distillate, leaving behind impurities or other substances with higher boiling points. This process helps in obtaining a purer form of the desired compound.
Importance of Switching the Receiving Flask
It is crucial to switch the receiving flask after reaching 100 ∘ C during distillation to ensure the collection of purer fractions. By doing so, the distillate of the higher boiling point compound, like nitrobenzene, can be separated from the distillate of the lower boiling point compound, such as methylene chloride. This switch helps in obtaining a more refined product through simple distillation.
Gentle Inverting in Extraction
During the extraction step, a gentle inversion of the separatory funnel is required to mix the two immiscible layers efficiently. This gentle swirling motion aids in extracting the desired component without vigorously shaking the funnel, which could lead to the formation of an emulsion. Emulsions pose challenges in separating the components, making the gentle inversion crucial for a successful extraction process.