To a solution of
33 g. (0.5 mole) of potassium hydroxide (Note
1) in 1.5 l. of distilled water in a
5-l. flask or other appropriate container fitted with a
mechanical stirrer is added
80 g. (0.5 mole) of methyl hydrogen adipate (Note
2). With continuous stirring a solution of
85 g. (0.5 mole) of silver nitrate in 1 l. of distilled water is added rapidly (about 15 minutes). The precipitated
methyl silver adipate is collected on a
Büchner funnel, washed with
methanol, and dried in an oven at 50–60°. For the next step the dried silver salt is finely powdered and sieved through a 40-mesh screen. The combined yield from two such runs is
213 g. (
80%).
The
213 g. (0.8 mole) of finely powdered silver salt is placed in a
1-l. three-necked flask (Note
3); two necks of the flask are stoppered, and the third is connected to a
water pump through a
U-tube or flask containing Drierite. The flask is then placed in an
oil bath and evacuated to a pressure of about 15 mm. The temperature of the oil bath is maintained at 100–110° for 36 hours (Note
4) and (Note
5).
The pressure in the flask is restored to that of the atmosphere. The flask is removed from the oil bath and equipped with a
dropping funnel,
condenser, and mechanical stirrer (Note
6). To the salt is added
350 ml. of dry carbon tetrachloride (Note
7); the stirrer is started, and
117 g. (40 ml., 0.73 mole) of dry bromine (p. 790, Note 2) is added through the dropping funnel over a 30- to 40-minute period. Occasional cooling may be necessary as the reaction is quite vigorous at first. When all the
bromine has been added, the mixture is heated for 1 hour on a
steam bath. It is then filtered and the
silver bromide washed thoroughly on the filter with
100 ml. of warm carbon tetrachloride. The filtrate is washed once with
100 ml. of 10% sodium carbonate solution and dried over
30–40 g. of Drierite. The solvent is removed and the residue distilled under reduced pressure. The yield of product boiling at
75–80°/4 mm. is
101–106 g. The yield is
65–68% based on the weight of the
methyl silver adipate before drying under reduced pressure, or
52–54% based upon
methyl hydrogen adipate.