Organic Syntheses, Coll. Vol. 4, p.892 (1963); Vol. 36, p.89 (1956).
A 5-l. round-bottomed three-necked flask
equipped with a mechanical stirrer
, a reflux condenser (Note 1)
, and two 250-ml. dropping funnels
(mounted with the aid of a Y-tube) is charged with 1.7 l. of dimethylformamide (Note 2)
. The flask is heated until the dimethylformamide
is almost refluxing. Then, with stirring, 280 ml. (318 g., 2.5 moles) of 1,4-dichlorobutane
and a solution of 359 g. (2.75 moles) of 60% sodium sulfide (Note 2)
in 1 l. of hot water are added simultaneously from the dropping funnels at such a rate that the mixture refluxes without application of heat (Note 3)
. After the addition is complete (about 1.5 hours), the mixture is heated at reflux with stirring for an additional 2 hours. The condenser is arranged for distillation, and 600 ml. of distillate is collected (Note 4)
. The distillate is made alkaline by adding 20 g. of sodium hydroxide
, and sodium chloride
is added to the saturation point. The aqueous layer is separated and discarded, and the crude tetrahydrothiophene
layer is dried over solid potassium hydroxide
. Distillation through a 30-cm. Vigreux column
gives, after a small fore-run (Note 5)
, 160–172 g.
) of colorless tetrahydrothiophene
, b.p. 119–121°
1.5000–1.5014 (Note 6)
and (Note 7)
The reaction should be carried out in a hood
, or the outlet of the condenser should be connected to a fume trap
Technical grade DMF is available from the Grasselli Chemicals Department of E.I. duPont de Nemours and Company
. The 1,4-dichlorobutane was obtained from the Electrochemicals Department, E. I. duPont de Nemours and Company
. Technical Baker and Adamson fused chip sodium sulfide
assaying 60% sodium sulfide
was used. The checkers obtained somewhat lower yields when the appropriate amount of reagent grade Na2S·9H2O
was employed instead of the technical material.
The addition of the reactants takes approximately 1.3 hours and should be carried out so that the addition of both reactants is completed at approximately the same time.
solution may be used repeatedly if each time the volume is reduced by the distillation of the remaining water. After two runs the accumulated sodium chloride
should be removed by filtration.
A small amount of dimethylamine
is always present in the crude product. This is removed before collection of the product by operating the column under total reflux for 1–2 hours. The vent of the still head should be connected to a hood during this operation. If foaming does not subside after this treatment the use of a 1-l. still pot is indicated.
When several runs are made, an additional amount of the product can be obtained by redrying and redistilling the foreruns. The submitters have obtained yields as high as 90% on a larger-scale operation.
The reaction may also be carried out in aqueous medium with an increase in the time of reaction to 4 hours. By this method the submitters obtained a 78%
yield on a large-scale run. When only a single run is to be made, this procedure may be preferred as a matter of economy.
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