In a recrystallization of vanillin, can you purify a substance whose solubility decreases as the temperature increases?
Jim and others, don't be impolite by responding "I don't know."
Answered above. You may want to get a second opinion.
Anonymous, wtf you talkin bout
Yes, it is possible to purify a substance whose solubility decreases as the temperature increases through recrystallization. Recrystallization is a common technique used in chemistry to purify solid compounds, which takes advantage of the differences in solubilities of the desired compound and impurities in various solvents at different temperatures.
To purify a substance with decreasing solubility as temperature increases, you need to find a suitable solvent that can dissolve the substance well at higher temperatures but has low solubility at lower temperatures, allowing the substance to crystallize out.
In the case of vanillin, which has decreasing solubility in water as temperature increases, you can start by dissolving your crude vanillin sample in hot water. Heating the mixture allows the vanillin to dissolve completely due to its higher solubility at elevated temperatures. However, as the mixture cools down, the solubility of vanillin decreases, leading to the formation of vanillin crystals.
At this stage, you need to filter the mixture to separate the solid vanillin crystals from any remaining impurities in the solution. This can be achieved by using a filtration setup such as a Buchner funnel. The solid vanillin crystals collected from the filtration process can then be washed with a cold solvent (e.g., ice-cold water) to remove any remaining impurities that may be stuck to the crystal surface.
Finally, the purified vanillin crystals can be dried to remove any remaining solvent, typically by placing them in an oven or desiccator.
It is important to note that the choice of solvent for recrystallization depends on the compound's solubility properties. You may need to experiment with various solvents to find the one that provides the best purification results. Additionally, other factors, such as the choice of filter paper and proper drying techniques, should also be considered to ensure a successful recrystallization process.