Divinyl sulfide

Divinyl sulfide is the organosulfur compound with the formula S(CH=CH2)2. A colorless liquid with a faint odor, it is found in some species of Allium.

Preparation
Divinyl sulfide is formed from hydrogen sulfide and acetylene. Divinylsulfide can arise when inadvertantly when acetylene is generated by hydrolysis of technical-grade calcium carbide contaminated with calcium sulfide.

Divinylsulfide was first prepared in 1920 by the reaction of bis(2-chloroethyl)sulfide with sodium ethoxide:
 * (ClCH2CH2)2S +  2 NaOEt   →  (CH2=CH)2S  +  2 EtOH  +  2 NaCl

Monovinyl sulfides
With the formula CH2=CHSR, a variety of monovinyl sulfides are known. They can arise by the dehydrohalogenation of -2-haloethyl phenyl sulfides. One example is phenyl vinyl sulfide. Alkyl ketones react with thiols in the presence of phosphorus pentoxide to give vinyl sulfides:
 * RSH + CH3C(O)R'  ->  CH2\dC(SR)R'  +  H2O