An intimate mixture of
166 g. (1.2 moles) of anhydrous potassium carbonate (Note
1) and
294 g. (2 moles) of phthalimide is treated with
506 g. (4 moles) of benzyl chloride (Note
2), and the mixture is heated in an
oil bath at 190° under a
reflux condenser for three hours (Note
3). While the mixture is still hot, the excess
benzyl chloride is removed by steam distillation (Note
4). Near the end of this operation the
benzyl phthalimide crystallizes. It is advisable to cool the mixture rapidly with very vigorous agitation so that the material is in as fine a state of division as possible. The solid is filtered on a
large Büchner funnel, thoroughly washed with water, and drained as completely as possible by suction. It is then washed once with
400 cc. of 60 per cent alcohol and drained again. The yield of this product, melting at
100–110°, is
340–375 g. (
72–79 per cent of the theoretical amount). It is conveniently purified by crystallizing from glacial
acetic acid. The recovery in the crystallization is about
80 per cent, and the pure product melts at
116° (corr.) (Note
5).