A mixture of
250 g. (1.46 moles) of p-nitrobenzyl chloride,
225 g. (2.74 moles) of fused sodium acetate, and
375 g. (6.25 moles) of glacial acetic acid is refluxed for 8–10 hours in a
2-l. flask heated by an
oil bath, the temperature of which is maintained at 160–170° (Note
1). After this time the bath is allowed to cool to about 125°, and the
acetic acid is removed by distillation under reduced pressure. Care must be taken not to reduce the pressure too rapidly in the early stages of the distillation. As the distillation slows down, the pressure is further reduced until it reaches 50 mm. or lower, and the temperature is slowly raised to 160°. From 2.5 to 3 hours is required for the complete removal of the
acetic acid. About 500 ml. of water is added, and the hard cake is broken up with a
stirring rod (Note
2).
The entire contents of the flask are then transferred to a
1.5-l. beaker and stirred with a
mechanical stirrer for about 30 minutes or long enough to break up all the lumps. The finely divided material is filtered on a
Büchner funnel and washed with 200 ml. of cold water. The above process of washing, stirring, and filtering is repeated twice. The product is then transferred to a 1.5-l. beaker, and
500 ml. of methanol is added and heated to boiling in order to effect solution. The hot solution is filtered through a heated Büchner funnel and allowed to cool slowly. When the solution has cooled to 20°, the product is collected on a filter and air-dried. This first crop consists of yellow needles which melt at
74–77° and weigh
215–225 g. The filtrate is evaporated to 100 ml. and cooled. An additional
25–30 g. of solid separates. Both crops are again washed with cold water and recrystallized from
500 ml. of hot methanol. The first crop from this second crystallization weighs
210–218 g. and melts at
77–78°. Evaporation of the filtrate to 100 ml. and cooling yield an additional
15–18 g. of
acetate which is purified by recrystallization from
methanol; about
12 to 15 g. of product is obtained. The combined yield of pale yellow crystals which melt at
77–78° amounts to
222–233 g. (
78–82%).