(CAS NO. ) is prepared commercially by Diels-Alder reaction of 1,3-butadiene and sulfur dioxide, followed by Raney nickel hydrogenation. The principle impurities are water, 3-sulfolene, 2-sulfolene and 2-isopropyl sulfolanyl ether. It is dried by passage through a column of molecular sieves. Distd under reduced pressure through a column packed with stainless steel helices. Again dried with molecular sieves and distd.

Also, Sulfolane was stirred at 50°C and small portions of solid KMnO₄ were added until the colour persisted during 1 h. Dropwise addition of MeOH then destroyed the excess KMnO₄, the soln was filtered, freed from potassium ions by passage through an ion-exchange column and dried under vacuum. It has also been vacuum distd from KOH pellets. It is hygroscopic. Coetzee has reviewed the methods of purification of sulfolane, and also the removal of impurities.