Preparation and Isornerization of Hexafluoropropene Oligomers in the Presence of Fluoride Ion

In KF- or KHF2-DMF system hexafluoropropene was oligomerized at room temperature and under atmospheric pressure to give a mixture of dimers and trimers. Total yield of these oligomers was almost quantitative. The molar ratios of dimers to trimers, and the com- positions of isomers [1]-[5] were determined by gas chromatography (Table 1). In KF- or KHF2-MeCN system, dimer [1] was formed almost exclusively.By the action of KF-DMF at high temperature, a part of dimer [1] was isomerized into thermodynamically more stable dimer [2], whereas trimer [4] was isomerized even at room temperature into trimer [5].