Adsorption and conductivity studies in oxychlorination catalysis. Part 3.—The ethene–transition-metal chloride interaction

Abstract

Gas adsorption chromatography (g.a.c.) has been used to obtain isotherms and isosteric heats of adsorption of C₂H₄ at temperatures < 150 °C on VCl₃, CrCl₃, CrCl₂, MnCl₂, FeCl₂, CoCl₂, NiCl₂, CuCl₂ and CuCl. Physical adsorption is indicated for CrCl₂, MnCl₂ and CuCl and chemisorption for NiCl₂ and CuCl₂; the others occupy an intermediate position. The results are discussed in terms of d-electron configuration and ion charge/(radius)² ratio. G.a.c. studies of C₂H₄ on PdCl₂, PtCl₂ and PtCl₄ indicate that chemical reaction occurs at room temperature. For those adsorbents for which heats of adsorption had been obtained, further reaction was initiated by increasing the temperature above 150 °C. Reaction products, e.g. HCl, vinyl chloride, dichloroethane and polymers, were identified, where possible, by mass spectrometry or chromatography. The capabilities of a microreactor to study the copper chloride–C₂H₄ system have been evaluated.