Discuss your choice of solvent for extraction of cholesterol from gallstones (We
ID: 893274 • Letter: D
Question
Discuss your choice of solvent for extraction of cholesterol from gallstones (We chose 2-butanone). Discuss each solvent and how polarity and intermolecular forces in solvent and cholesterol influence solubility. Broaden your discussion to hypothesize whether cholesterol would be very soluble in an organic solvent as hexane (C6H12). Explain your reasoning. Finally address your choice of solvent (Methanol) in re-crystallization of Cholesterol. What makes a solvent good for re-crystallization? What chemical differences are needed between extraction solvent and re-crystallization solvent?
Explanation / Answer
Polarity and intermolecular forces play a key role in solubility. Since cholesterol is an organic compound it is soluble in organic solvents which are non-polar ( 2 - butanone) and the intermolecular forces are of the same order in 2-butanone as that of Cholesterol.
Cholesterol would be soluble in hexane but not highly soluble due to the difference in order of intermolecular forces.
Methanol can be used as a solvent for re-crystallization. A good solvent for re-crystallization is one in which impurities are more soluble than the compound which is to be dissolved when the solvent is hot. When the solvent is cooled the impurities must stay soluble while the compound precipitates.
Chemical differences between extraction solvent and re-crystallization solvent is the compound should dissolve in the solvent at boiling point in case of recrystallization which is not necessary for extraction solvent which occurs at a particular temperature.