Why does acetanilide remain in the organic layer during the extractions with bases?
The correct answer and explanation is:
Acetanilide remains in the organic layer during extractions with bases because it is a neutral compound. To understand why this happens, it’s important to consider the solubility of acetanilide in different solvents and the effect of bases on its structure.
Acetanilide, an amide compound, contains a functional group (amide) that is relatively non-basic. When a base is added to an organic compound like acetanilide, the base typically deprotonates acidic functional groups (such as phenols or carboxylic acids). This deprotonation results in the formation of anionic species that are more soluble in water, which is polar, than in organic solvents, which are non-polar.
However, acetanilide does not possess a sufficiently acidic proton that would allow it to ionize under basic conditions. As a result, acetanilide remains in its neutral form. Neutral compounds are generally more soluble in organic solvents like diethyl ether or dichloromethane than in aqueous solutions. In extractions involving a basic aqueous solution, basic substances like sodium hydroxide or sodium bicarbonate typically extract acidic compounds by converting them into their anionic forms, but acetanilide, being neutral, is not affected by the base and therefore stays in the organic layer.
In conclusion, acetanilide remains in the organic layer during extractions with bases because it lacks a sufficiently acidic hydrogen to undergo ionization, making it insoluble in aqueous solutions and soluble in the organic solvent. This behavior is characteristic of neutral organic compounds that do not participate in acid-base reactions under typical extraction conditions.