Ninety-eight grams (1 mole) of cyclohexene oxide (Note
1) is divided into two approximately equal portions; one portion is added to a solution of
121 g. (1.25 moles) of potassium thiocyanate in 100 ml. of water and
75 ml. of 95% ethanol. After standing for 3–4 hours (Note
2) the clear solution is transferred to a
1-l. flask equipped with a
mechanical stirrer. The second portion of oxide is added, and the resulting solution is stirred vigorously for 36 hours at room temperature. The supernatant layer and the aqueous phase are then decanted from the precipitated
potassium cyanate into a
1-l. separatory funnel. The
potassium cyanate is rinsed with
50 ml. of ether, which is subsequently added to the separatory funnel and used to extract the
cyclohexene sulfide. The
ether extract is washed twice with
50-ml. portions of saturated sodium chloride solution and then dried over
anhydrous sodium sulfate. The excess
ether is removed on the
steam bath, and the residual liquid is distilled under reduced pressure through an
18-in. Vigreux column while the distillate is being cooled in ice. The main fraction boils at
71.5–73.5°/21 mm. (
69–71°/19 mm.) (Note
3);
n25D 1.5306–1.5311. A fore-run, boiling up to
71.5°/21 mm., yields more of the product on redistillation. The total yield of
cyclohexene sulfide is
81.5–83.5 g. (
71–73%).