Several smaller runs of 25 g. of phthalic anhydride gave
the same percentage yield.
Phthalimide may be recrystallized from water, but only about 4 g.
of phthalimide will dissolve in a liter of boiling water.
It may also be crystallized from alcohol, in which solvent it dissolves
to the extent of five parts in a hundred at boiling temperature.
On a large scale, it would be advisable to collect the small amount
of ammonia given off during the reaction.
If desired, the product obtained by pouring the reaction mass
into the crock may be treated with hot water to soften the cake,
broken up with a glass rod, transferred to a flask and boiled with water
for a few minutes. This treatment, however, is quite unnecessary;
for all practical purposes, the crude cake, as it is obtained,
may be ground up and used directly.