The present invention relates to compositions of matter that are ionic liquids, the compositions comprising any of eleven cations combined with any of three fluorinated sulfonated anions. The disclosed process includes a method of separating epoxybutene from the solvent and other reaction by-products by a novel combination of distillation and decantation steps. Stereo correspondences between contour points on corresponding scanlines in the two contour images are calculated on the basis of contour point comparison metrics, such as the compatibility of the normal of the contours andor a distance along the scanline between the point and a centroid of the contour.