Benzocaine synthesis: Why are we using both water and methanol?

Question

To purify the product, it will be boiled in water, then hot methanol will be added until the solid just dissolves. The mixture will be allowed to cool, and the product that recrystallizes will be collected by vacuum filtration. Why are we using both water and methanol?

A). Because if we only use methanol, the product will not completely recrystallize.

B). Because if we only use water, the product will not completely recrystallize.

C). Because if we only use water, the impurities will not recrystallize.

D). Because if we only use methanol, the impurities will not dissolve.

Answer 1

Benzocaine in not very soluble in water (but hopefully the impurities are), and it is fairly soluble in methanol (and hopefully the impurities aren't). This technique is known as mixed solvent recrystallization. Of the choices provided, the best answer seems to be ...

D). Because if we only use methanol, the impurities will not dissolve.