A
1-l. round-bottomed three-necked flask is fitted with a sealed stirrer (Note
1), a
dropping funnel, and a
reflux condenser, through which a
thermometer extends nearly to the bottom of the flask. In the flask are thoroughly mixed
40.5 g. (0.62 g. atom) of zinc dust (Note
2) and
100 ml. of glacial acetic acid, and to this mixture is added
42.5 g. (0.25 mole) of sebacoin (p.840) (Note
3). The mixture is stirred rapidly, and
90 ml. of concentrated C.P. hydrochloric acid is added dropwise during a period of 5 to 10 minutes, or as fast as control of foaming and temperature permits. The temperature must be kept between 75 and 80° (Note
4), and cooling by a
water bath may be necessary during the addition of the
hydrochloric acid. Stirring is continued for 1.5 hours at 75–80°. Thirty minutes after the initial addition of
hydrochloric acid, and again 30 minutes later,
90-ml. portions of concentrated hydrochloric acid are added to the mixture while the temperature is maintained at 75–80°. After the reaction is complete, the remaining
zinc is separated from the cooled mixture by decantation (Note
5). The liquid phase is diluted with
700 ml. of saturated aqueous sodium chloride solution and extracted with four
250-ml. portions of ether, each of which is first used to wash the residual
zinc (Note
6). The
ether extracts are combined and washed with
250 ml. of saturated sodium chloride solution, three
250-ml. portions of 10% sodium carbonate solution (foaming!), and finally
250 ml. of saturated sodium chloride solution. The ethereal solution is dried over
anhydrous magnesium sulfate (about 25 g. is needed). After the drying agent has been removed by filtration and the solvent by distillation, the residue is distilled at reduced pressure through an
efficient column (Note
7). After a small fore-run consisting mostly of
cyclodecane, cyclodecanone is collected at
99–101°/8 mm. The yield is
29–30 g. (
75–78%),
n25D 1.4808–1.4810 (Note
8).