What is "sulfolene"

n. (context organic compound English) The sulfone ''2,5-dihydrothiophene 1,1-dioxide'' formed by the cycloaddition of sulfur dioxide to butadiene

Sulfolene, or butadiene sulfone is a cyclic organic chemical with a sulfone functional group. It is the product of a (4+1) cycloaddition (or more technically a cheletropic reaction) between butadiene and sulfur dioxide.

Catalytic hydrogenation yields sulfolane, a solvent used in the petrochemical industry for the extraction of aromatics from hydrocarbon streams. In the laboratory it is used as a solid source of butadiene, into which it decomposes by a reverse cycloaddition. However, the sulfur dioxide that is generated as a side product may cause side reactions with acid-sensitive substrates.

In electrochemical fluorination, butadiene sulfone can increase the yield of perfluorooctanesulfonyl fluoride by about 70%. It is "highly soluble in anhydrous HF and increases the conductivity of the electrolyte solution." In this application, it undergoes a ring opening and is fluorinated to form perfluorobutane sulfonyl fluoride.