环丁砜又名四氢噻吩-1，1-二氧化物，为无色透明液体，是一种优良的非质子极性溶剂，可与水、丙酮、甲苯等互溶。也是石油化工上芳烃抽提工艺中的理想试剂。

Sulfolane (also tetramethylene sulfone, systematic name: 2,3,4,5-tetrahydrothiophene-1,1-dioxide) is an organosulfur compound, formally a cyclic sulfone, with the formula (CH₂)₄SO₂. It is a colorless liquid commonly used in the chemical industry as a solvent for extractive distillation and chemical reactions. Sulfolane was originally developed by the Shell Oil Company in the 1960s as a solvent to purify butadiene. Sulfolane is a polar aprotic solvent, and it is readily soluble in water.