This invention relates to a process for the preparation of 1,1-difluoroolefins, e.g., difluorovinyl cycloaliphatic compounds such as difluorovinylcyclohexane and derivatives by the dehydrofluorination of a trifluoromethyl-substituted cycloaliphatic compound and the resulting compositions. This method utilizes a "sterically hindered super-base" system represented by the formula M^+-NRR^-; where M is Na or K and R is a secondary, or tertiary alkyl or cycloalkyl group of amines for effecting dehydrofluorination of the trifluoromethyl group leading to the difluorovinyl based cycloaliphatic compounds. The sterically hindered super base can be formed by the, in situ, reaction of a sodium or potassium alkoxide, e.g., KtBuO with a lithium dialkylamide where the lithium is bonded to nitrogen atom of an amine bearing secondary or tertiary aliphatic groups.