Microscale Crystallization of Sulfanilamide
Microscale Crystallization of Sulfanilamide
Purpose
The purpose of the experiment was to use the crystallization technique to purify the solute sulfanilamide using 95% ethanol as the solvent, to calculate the amount of sulfanilamide that was recovered, and to determine the purity of the final product.
Introduction
In this experiment, recrystallization will be the method used to purify the solute sulfanilamide using ethanol as the solvent. Based on the solubility curve on the solubility versus temperature graph, the ideal solvent will allow the solute to be soluble at higher temperatures and insoluble at lower temperatures, thus making ethanol an excellent solvent for crystallizing sulfanilamide. Sulfanilamide is first dissolved in the smallest amount of ethanol just enough to dissolve the sulfanilamide and then left undisturbed to cool. It is important that cooling be slow in order to achieve the best results. The solute will become less and less soluble as the temperature decreases and will start to separate from the solution and form crystals.
Only molecules with the right shape will fit into the crystals structure as the other molecules that make the substance impure will stay in the solution. Thus, the process of recrystallization is slow and selective. After recrystallization, the purity of the final product will be determined by observing its
crystals and finding its melting point. The melting point is usually expressed as a range. The first
number is the temperature at which melting is first observed and the second number is the
temperature at which the solid is completely melted. Pure substances will have a higher
melting point and a narrower melting point range closer to the literature value versus impure
substances which will have a lower melting point and a larger range. The literature
melting point of pure sulfanilamide is 164.5 – 166.5°C. By using the recrystallization technique
and observing
Purpose
The purpose of the experiment was to use the crystallization technique to purify the solute sulfanilamide using 95% ethanol as the solvent, to calculate the amount of sulfanilamide that was recovered, and to determine the purity of the final product.
Introduction
In this experiment, recrystallization will be the method used to purify the solute sulfanilamide using ethanol as the solvent. Based on the solubility curve on the solubility versus temperature graph, the ideal solvent will allow the solute to be soluble at higher temperatures and insoluble at lower temperatures, thus making ethanol an excellent solvent for crystallizing sulfanilamide. Sulfanilamide is first dissolved in the smallest amount of ethanol just enough to dissolve the sulfanilamide and then left undisturbed to cool. It is important that cooling be slow in order to achieve the best results. The solute will become less and less soluble as the temperature decreases and will start to separate from the solution and form crystals.
Only molecules with the right shape will fit into the crystals structure as the other molecules that make the substance impure will stay in the solution. Thus, the process of recrystallization is slow and selective. After recrystallization, the purity of the final product will be determined by observing its
crystals and finding its melting point. The melting point is usually expressed as a range. The first
number is the temperature at which melting is first observed and the second number is the
temperature at which the solid is completely melted. Pure substances will have a higher
melting point and a narrower melting point range closer to the literature value versus impure
substances which will have a lower melting point and a larger range. The literature
melting point of pure sulfanilamide is 164.5 – 166.5°C. By using the recrystallization technique
and observing