C. Rganic
1977
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Journal
Acta Chimica Sinica
Abstract
ABSTRACT 5-Iodo-3-oxaperfluoropentanesulfonyl fluoride ICF_2CF_2OCF_2CF_2SO_2F,(Ⅲ)is pre. pared in a three-component reaction involving the adduct of tetrafluoroethane sultone (Ⅰ)or fluorocarbonyl perfluoro-methane-sulfonyl fluoride(Ⅱ)with potassium fluoride, tetrafluoroethylene and iodine monochloride or iodine in diglyme at 30~50℃.The iodide(Ⅲ)can be telomerized with tetrafluoroethylene to give telemors I(CF_2CF_2)_(n+1~-) OCF_2CF_2SO_2F,where n=1,2,3,4,….These telemors can be fluorinated by swarts method.The potassium salts of the corresponding compounds are formed by treating the sulfonyl fluorides with potassium hydroxide.The structures of all compounds obtained have been deduced from their elementary analyses,IR,~(19)F NMR and GC. The potassium salts of oxaperfluoroalkanesulfonic acids have been applied in chromium plating as an excellent suppression agent of chromic acid mist.In an actual electroplating plant test,where the tank ventilation was turned off,the maximum concentrations of CrO_3 of 0.005~0.002 mg per m~3 of air were observed when 0.02~ 0.04g per liter of the salt was added to the chromium plating solution.Thus,itcan reduce toxicity hazards to personal,save 20~30% of the total chromic acid used,and dispense with the special,expensive ventilation facilities and power.During the electro-deposition of chromium the addition of the potassium salt does not influence the brightness but, to some extent,improves the cracks and hardness of the plated articles.The results from metallographic analyses and high pressure tests of plated species show that the binding force between the chromatized layer and the basic metallic layer is good. Cathodic polarization and surface tension curves under various concentrations of the potassium salt have also been determinated respectively.