WATER, METHANOL, CHLOROFORM, WHICH OF THIS THREE IS MOST SUITABLE FOR RECRYSTALLIZATION FOR ACETANILIDE?
AND WHICH IS NOT SUITABLE?
To determine the most suitable solvent for the recrystallization of acetanilide, we can consider a few factors:
1. Solubility: Acetanilide should be soluble in the solvent at high temperatures to dissolve the impurities and then be insoluble at lower temperatures to allow recrystallization.
2. Difference in boiling points: The solvent should have a boiling point lower than the melting point of acetanilide (114-116 °C) to facilitate the evaporation of the solvent without decomposition of the compound.
Water, methanol, and chloroform all can be used for recrystallization, but each has different properties:
1. Water (H2O): It is a common solvent and is widely available. Acetanilide is moderately soluble in water at high temperatures and recrystallizes well at lower temperatures. Water is often a good choice for recrystallization due to its low cost and high accessibility.
2. Methanol (CH3OH): Methanol is a polar solvent and has a lower boiling point than acetanilide, making it suitable for recrystallization. However, acetanilide is more soluble in methanol compared to water. Therefore, there is a possibility that impurities might also dissolve. Methanol can be used, but it might require additional steps to remove impurities.
3. Chloroform (CHCl3): Chloroform is a nonpolar solvent. Acetanilide is slightly soluble in chloroform at high temperatures, but it precipitates out when the solution is cooled. Chloroform can be used for recrystallization, especially when impurities are nonpolar, as they would remain dissolved while acetanilide recrystallizes.
Based on these considerations, water would be the most suitable solvent for recrystallizing acetanilide because it dissolves the compound well at high temperatures and allows for efficient recrystallization at lower temperatures. Methanol and chloroform can also be used but may require additional steps to remove impurities.