Donor-acceptor complexes formed by perfluoro-organo bromides and iodides with nitrogenous and other bases. I. Vapour pressure measurements

Abstract

Vapour pressure measurements of systems of the type perfluorocarbon bromide or iodide-trimethylamine have been made. These measurements clearly show that, at sufficiently low temperatures, a solid 1 : 1 adduct is reversibly formed. For the systems 1,2- dibromotetrafluoroethane-trimethylamine and trifluoro-methyl bromide- tetramethylethylenediamine 1 : 2 and 2 : 1 halide-amine adducts respectively were also observed. These stoicheiometries show that the dominant interaction leading to adduct formation is between the nitrogen and bromine atoms. Systems giving 1 : 1 stoicheiometry were examined at higher temperatures at which liquid and vapour but no solid phase is present. Strong negative deviations from ideality consistent with 1 : 1 interactions were observed. Approximate values of the thermodynamic quantities pertaining to the interaction have been derived.