Photo-induced Telomerization Synthesizes Perfluoroalkyl Iodide

The research plan of perfluoroalkyliodine synthesis by gas phase telomeric reaction under normal pressure and medium temperature is put forward on the basis of literature review. Photo-initiation has many unique advantages: First of all, photo-initiation does not introduce impurity other than the raw materials, the products given are homologues which are easy to be separated. Secondly, photodecomposition of molecular can be carried out at any temperature, and only cause a certain given chemical bond to break, formed free radicals and energy distribution are simpler than thermal decomposition, the longer life span of the free radicals makes the chemical reaction relative simple.The key conditions such as telomeric reaction temperature, cold trap temperature, feeding ratio at low pressure Hg light are explored experimentally. Under the suitable conditions evaluated of reaction temperature 100 C, cold trap temperature 8-20 C and feeding ratio C2F4/C2F5I=3.7:1 (molar), the composition of two useful ingredients, C6F13I and C8F17I can be excess 50%. Meanwhile, the relative response factors of C2nF2n+1I on hydrogen flame detector are determined, which are in turn used to quantitatively analyze the concentrations of raw materials and resultants on Agilent 4890B GC by normalization.Separation method and the related physical properties of teleomer are also studied in the paper. Vapor pressure data of key ingredient perfluoro iodine butane , perfluoro iodine hexane and perfuloro iodine octane are determined for the first time, and Antoine equation constants of the three substances are correlated, which are the fundamental data for distillation separation design and operation. Distillation research indicates perfuloro alkyl iodine teleomer can be separated through rectification to get a product of enough purity, and the light composition can be used as the material in teleomeric reaction.