When performing a liquid-liquid extraction, which phase is typically collected for more polar compounds?

In liquid-liquid extraction, the process involves separating compounds based on their solubility in two different immiscible liquids, typically an organic solvent and water. When targeting more polar compounds, the aqueous phase is typically collected because polar compounds have a greater affinity for water, which is a polar solvent.

Polar compounds, such as alcohols, carboxylic acids, and amines, interact more favorably with water due to hydrogen bonding and dipole-dipole interactions. This affinity causes them to remain dissolved in the aqueous layer while non-polar compounds tend to be extracted into the organic layer, which is usually less polar. Therefore, when performing an extraction with the goal of isolating polar compounds, the aqueous phase will contain these compounds, making it the correct choice in this context.

Other phases mentioned do not align with the characteristics of polar compounds; the organic phase typically contains less polar or non-polar compounds, while the vapor and solid phases are not relevant to the liquid-liquid extraction process focused on polar versus non-polar separation.