Abstract
Catalytic dimerization of tetrafluoroethylene (CF2=CF2, TFE) over metal supported catalysts was carried out to control the selectivities of octafluorocyclobutane (cyclo-C4F8, RC318) and hexafluoropropylene (CF3CF=CF2, HFP). The metal supported catalyst was prepared by an impregnation method, and characterized by N2 physisorption, XRD and TEM. TFE was prepared by the pyrolysis of chlorodifluoromethane (CHClF2, R22) with a superheated steam dilution at the temperature ranges of 750 ∼ 950°C and then used a raw material for the catalytic dimerization of TFE after distillation. In the catalytic dimerization of TFE, RC318 and HFP were mainly produced with a little amount of by-product. It was found that the catalytic dimerization of TFE is more desirable process than the conventional non-catalytic dimerization under the reaction conditions of 480 ∼ 680°C and atmospheric pressure. It was also found that 3wt% Ru/AC catalyst showed higher activity than the other catalyst, and 3wt% Zn/AC catalyst represented higher selectivity for RC318. The results suggest that 3wt% Ru/AC catalyst is a promising candidate as a catalyst for co-producing RC318 and HFP by the catalytic dimerization of TFE.
