A mixture of
140 g. (0.82 mole) of sebacoin (p. 840) (Note
1),
50 g. of copper chromite catalyst2 (Note
2), and
230 ml. of 95% ethanol is placed in an
800-ml. high-pressure hydrogenation bomb (Note
3).
Hydrogen is admitted to the bomb at 135 atm., and the bomb is heated to 150°. When this temperature is reached, the shaker is started. The temperature is stabilized at 150° after its initial rapid fluctuation, and the hydrogenation is allowed to proceed until the mixture ceases to absorb
hydrogen (2–4 hours). The heating and shaking are discontinued, and the bomb is allowed to cool to room temperature. The excess
hydrogen is vented, and the bomb is dismantled.
The
cis-1,2-cyclodecanediol will have crystallized out of solution, while the
trans-diol remains in the
ethanol. The entire mixture is washed out of the bomb with
95% ethanol (about 1 l.). The
cis-glycol is redissolved by heating the ethanolic mixture at reflux temperature. Filter aid ("Celite") is added to the mixture, and the hot mixture is filtered through a bed of filter aid on a
Büchner funnel to remove the catalyst. The
ethanol is removed from the filtrate by distillation on a
steam bath under water-pump pressure. The residue is dissolved in a minimum of hot
1:1 benzene-ethanol solution (about 250 ml.), and the
cis-diol crystallizes upon cooling to room temperature. The crystals are collected by filtration, and the mother liquor is concentrated to dryness on a steam bath under water-pump pressure. The residue is again dissolved in a minimum of hot
1:1 benzene-ethanol (about 100 ml.), and additional
cis-diol crystallizes upon cooling in a refrigerator. The process is repeated using
50 ml. of 1:1 benzene-ethanol solvent. The total yield of
cis-1,2-cyclodecanediol is
68–73 g. (
48–52%), m.p.
137–138°.