The reaction is carried out in
1-l. three-necked round-bottomed flask fitted with a
ball-sealed mechanical stirrer, a
reflux condenser, and a
dropping funnel. The openings of the condenser and dropping funnel are protected from moisture by drying tubes. In the flask, which is protected from light (Note
1), are placed
170 g. (1.1 moles) of silver nitrite and
300 ml. of absolute ether. The
silver nitrite is suspended by vigorous stirring, and the mixture is cooled to 0° by an
ice bath. Then
155 g. (0.5 mole) of 1,4-diiodobutane (p.321) is added dropwise over a period of 3 hours. The temperature is maintained at 0° for an additional 2 hours, and then the reaction mixture is allowed to come slowly to room temperature (25°) by permitting the ice in the cooling bath to melt (Note
2). Twenty-four hours after the addition of the
diiodobutane has been completed, the solution is tested for unreacted iodide (Note
3). If the test is negative, the mixture is filtered and the
silver iodide washed with a total of
200 ml. of benzene (Note
4). The ethereal solution and the
benzene washings are combined, and the solvents are distilled on a
steam bath, the pressure being reduced (
water aspirator) toward the end of the distillation.
In a
500-ml. three-necked flask equipped with a
mechanical stirrer, a dropping funnel, and a
thermometer is placed
200 ml. of concentrated sulfuric acid. The flask is immersed in an
ice-salt bath, and the acid is cooled to 0–5°. The crude
dinitrobutane is added dropwise with vigorous stirring at such a rate that the temperature does not exceed 8°. Stirring is continued for an additional 10 minutes after completion of the addition. The solution is poured cautiously onto 1 kg. of crushed ice with manual stirring. The ice is allowed to melt, and the product is separated by suction filtration, washed with water, and air-dried. Recrystallization from
methanol at −70°, using a
Dry Ice-methylene chloride cooling bath, yields
30–34 g. (
41–46%) of
1,4-dinitrobutane, m.p.
33–34° (Note
5), (Note
6), (Note
7), and (Note
8).