GB823519A - A process for the preparation of fluorinated olefins - Google Patents

Abstract

Catalytic compositions used in the production of fluorinated olefins from hydrogen fluoride and a halogenated olefin (see Group IV (b)) comprise a fluoride of vanadium, manganese, iron, cobalt, nickel, titanium or silver on an inert support such as alumina, calcium oxide, charcoal, aluminium fluoride or calcium fluoride. Complex fluorides or oxyfluorides may be used as the catalyst. The compositions may be prepared by impregnating the support with an aqueous metal chloride solution and then reacting with hydrogen fluoride to form the metal fluoride. Generally about 1 g.-mol. of catalytic metal is used per 1400 g. of support.ALSO:Fluorinated propylenes are prepared by reacting a propylene of formula CY2 = CHCX3 in which each X and Y is chlorine, bromine, iodine or hydrogen, at least one X and one Y being halogen, with hydrogen fluoride in the presence of a fluoride of vanadium, manganese, iron, cobalt, nickel, titanium or silver at a temperature of at least 150 DEG C. whereby some or all of the halogens in the 1- and 3-positions are replaced by fluorine and the double bond shifts to the 3-position. The fluoride may be a simple salt such as FeF3, an oxyfluoride such as V2O2F4 or a complex salt such as K2TiF6. The catalyst may be on an inert support such as alumina, calcium oxide, charcoal, aluminium fluoride or calcium fluoride. Mixtures of catalysts may be used. The process may be operated continuously. Preferably a molecular excess of hydrogen fluoride over the olefine is used. The catalysts used in the examples were prepared by impregnating the support with an aqueous solution of the chloride of the metal, placing the wet mixture in the nickel tube reactor, saturing with HF and drying in an atmosphere of HF to convert the chloride to the fluoride. Generally 1 gm.-mol. of catalyst metal was used per 1400 g. of support. p