Benzyl alcohol (boiling point: 205 degrees C) was selected by a student to crystallize fluorenol (melting point: 153-154 degrees C) because the solubility characteristics of this solvent are appropriate. However, this solvent is not a good choice. Explain
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It would depend on the temp of recrystallizaton. If one used a temp above the mp of fluorenol, the solute would not crystalize, but come out as a liquid. It is above the bp.
РтЫн
Benzyl alcohol is not a good choice as a solvent to crystallize fluorenol due to the significant difference in boiling points of the two compounds.
When selecting a solvent for crystallization, it is important to consider the relative boiling points of the solvent and the compound to be crystallized. The solvent should have a boiling point lower than the melting point of the compound to allow for easy crystallization. However, in this case, benzyl alcohol has a boiling point of 205 degrees Celsius, while fluorenol has a melting point of 153-154 degrees Celsius.
The high boiling point of benzyl alcohol means that it would require an elevated temperature to evaporate the solvent, making it difficult to recover the pure fluorenol crystals. Additionally, heating the solution to such high temperatures could lead to the decomposition or degradation of the fluorenol compound. This could result in impurities and a decrease in the purity of the final product.
Therefore, a solvent with a lower boiling point should be chosen to ensure a successful crystallization process, with minimal temperature-induced degradation and easy recovery of pure crystals.
Benzyl alcohol may not be a good choice for crystallizing fluorenol due to its boiling point being significantly higher than the melting point of fluorenol.
The primary purpose of using a solvent for crystallization is to dissolve the substance at high temperatures and then allow it to slowly cool down, causing the solute to precipitate out as crystals. In this case, if benzyl alcohol were used, the high boiling point of 205 degrees Celsius would require the solvent to be heated to a temperature well above the melting point of fluorenol in order to dissolve it completely.
However, a good solvent for crystallization should preferably have a boiling point closer to the melting point of the solute. This allows for a more controlled cooling process, where the solute can slowly come out of solution and form crystals as the temperature decreases. When the solvent's boiling point is much higher than the solute's melting point, there is a risk of the solute re-dissolving as the solvent cools down, leading to incomplete or impure crystal formation.
In conclusion, benzyl alcohol is not a good choice to crystallize fluorenol due to its high boiling point, which is significantly higher than the melting point of fluorenol. A more suitable solvent with a boiling point closer to the melting point of fluorenol should be chosen to ensure successful and efficient crystallization.