writing out the mechanism for the benzocaine synthesis, i only see that it is similar to an esterification reaction, and that there is an acid catalyst, but i dont see what adding a base can do to the benzocaine product to let it precipitate out of solution
if benzocaine is basic, then in acidic conditions it will have at least a +1 charge, and since charged organic molecules are more soluble in water, the benzocaine is dissolved or suspended in the water...adding the base removes this positive charge on benzocaine, making it less soluble?