Edward F. Witucki

Preparation of 2-chloro-3-pentafluorosulfur tetrafluoropropylene, and its use in telomerization reactions

Abstract The synthesis of a new SF monomer, 2-chloro-3-pentafluorosulfur tetrafluoropropylene, SF 5 CF 2 C(Cl)CF 2 . is reported. We wish to report the synthesis of a new SF monomer, 2-chloro-3-pentafluorosulfur tetrafluoropropylene, SF 5 CF 2 C(Cl)CF 2 . The synthesis involves the following sequence of reactions: The preparation of (I), 1,2-dibromo-1,1,3,3-tetrafluoropropane, was carried out according to the method of Tarrant et al [1]. The preparation of (II), tetrafluoroallene (TFA), was essentially that of Muehlner [2] with slight modification. We were able to obtain consistent yields of about 70% using a larger excess of KOH with an efficient ice condenser. The reactor was heated slowly and held at about 90°C with a nitrogen sweep to remove TFA as it was formed. The preparation of (III), 2-chloro-3-pentafluorosulfur tetrafluoropropylene was carried out in a metal bomb at 90–100°C for 1 to 16 hours with a yield of 20 percent.

Addition of fluoroperoxides to perfluorovinylsulfur pentafluoride

Abstract The addition of CF 3 OOCF 3 and SF 5 OOSF 5 across the double bond in CFCFSF 5 was studied with 1:1 addition products being observed in both cases. For CF 3 OOCF 3 , the product was CF 3 OCF 2 CF(OCF 3 )SF 5 , whereas for SF 5 OOF 5 it was SF 5 CF 2 CF 2 OSF 5 . The different reaction paths are attributed to steric reasons. The telomerization of fluoroolefins with fluoroperoxides has been reported [1,2]. Hexafluoropropene, when telomerized with bis(trifluoromethyl) peroxide, (CF 3 O) 2 ,[1] yielded a series of oils having the composition CF 3 O(C 3 F 6 ) n OCF 3 where n 2 . Similarly, hexafluoropropene reacted with bis(pentafluorosulfur) peroxide, (SF 5 O) 2 , [2] to yield a series of oils of the composition SF 5 O(C 3 F 6 ) n OSF 5 where n was also equal to or larger than two. Surprisingly, in neither case was the 1:1 addition product found. During our investigation of new thermally stable high density fluorooils, the thermal and photochemical reactions of perfluorovinylsulfur pentafluoride, CF 2 CFSF 5 , with the fluoroperoxides (CF 3 O) 2 and (SF 5 O) 2 were studied. By analogy with the previous work on C 3 F 6 [1,2], the main products were higher telomers, however in the case of (CF 3 O) 2 and CF 2 CFSF 5 we were able to isolate also the 1:1 addition product according to: The necessary CF 3 O· radicals were generated either thermally at 185°C or by uv-photolysis at ambient temperature. The yields of (1) were 4% in the thermal and 8% in the photolytic reaction. Compound (l) is a clear liquid and was characterized by elemental analysis, molecular weight, and infrared and mass spectroscopy.