A sulfolane compound is prepared by reacting sulfur dioxide with an unsaturated organic compound containing two or more ethylenic linkages, in the absence of a solvent, to produce a molten sulfolene compound, introducing the molten sulfolene compound into a suitable hydrogenation solvent, pulling a vacuum on the resulting solution to remove a portion of the sulfur dioxide contained therein, adding hydrogen peroxide to the solution to convert any remaining sulfur dioxide to sulfur trioxide, addin...