1,2,2-Trifluorostyrene

[447-14-3] C8H5F3 (MW 158.12) InChI = 1S/C8H5F3/c9-7(8(10)11)6-4-2-1-3-5-6/h1-5H InChIKey = SUTQSIHGGHVXFK-UHFFFAOYSA-N (monomer for the preparation of polymers and copolymers that have application as ion exchange membranes for fuel cell separators)1, 2 Alternate Name: phenyltrifluoroethylene. Physical Data: colorless liquid, b.p. 68–70 °C/75 mm Hg.3 Solubility: soluble in most of the common organic solvents (THF, ether, hexanes, DMF, dioxane, benzene, etc). Preparative Methods: synthesis of 1,2,2-trifluorostyrene in good yield and high purity has been a difficult task.2-4 The most efficient preparation involved palladium(0)[Pd(PPh3)4] catalyzed cross-coupling of the trifluorovinylzinc reagent (CF2CFZnX) with iodobenzene.5 The trifluorovinylzinc reagent was generated either by direct insertion of zinc into bromotrifluoroethylene (CF2CFBr) (eq 1)5a, b or by in situ metallation/transmetallation of the readily available halocarbon 1,1,1,2-tetrafluoroethane (HFC-134a) with LDA in presence of zinc chloride (eq 2).5c Another high-yield preparation utilized dehydrohalogenation of C6H5CH(X)CF3 type precursor (where X = F, Cl) with a selective base like LiHMDS (the base should not consume the product styrene) to afford 1,2,2-trifluorostyrene.6 (1) (2) Purification: purified by column chromatography (silica gel and pentane as eluent) or by distillation under reduced pressure.5, 6 Handling, Storage, and Precaution: undergoes thermal cyclodimerization above 80 °C. Gradually decomposes to benzoic acid with the liberation of HF when exposed to air or moisture.2