Five Fluorine Iodoethane Catalytic Synthesis Of New Technology Research,

The catalytic synthesis of pentfluoroethyl iodide via the reaction of pentafluoroethane with iodine and oxygen under gas-solid phase conditions was studied,as well as the purification of used iodine.Be based upon the catalytic reaction,the reaction system was designed,including materials and catalyst preparation,high-temperature synthesis,reclamation of iodine,on-line monitoring etc.What's more,the experiment platform was formed with GC-MS,BET,XRD, ICP and other means.The influence on the catalytic activity was studied through some aspects,including active ingredient and ratio,loading,carrier,external and internal diffusion,reaction conditions (temperature,space velocity,molar ratio).The results showed that alkali metal salts as the active ingredient have higher activity,especially KF/RbNO₃ = 1:2(loading 20%,mass) has the best catalytic activity.It proved that catalysts which are carried by active carbon,alumina and aluminum fluoride play an important role in the reaction.However,wood active carbon is the most efficient carrier among them because of its higher surface area.After eliminating the influence of internal and external diffusion,the appropriate reaction conditions were obtained: reaction temperature was 550～600℃,space velocity was 75h^-1-130h^-1,range of molar ratio was n(C₂F₅H:I₂) = 1.25～1.75.The stability of catalyst was studied under the optimum conditions.It was found that the highest conversion of C₂F₅H was 60%and the yield of C₂F₅I was above 20%.Characterization results(BET,XRD,ICP) suggested that the surface area of AC declined and the active ingredient lost,which caused the catalytic activity lost.Two methods about melting and sublimation were carried out to purify.After contrast, sublimation method was chose to be enlarged.The results showed that the purity of iodine was above 99%.