TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The omega-iodide fluorine-containing ester is decarboxylated by dissolving the hydrolyzed substance of omega-iodide fluorine-containing ester in an organic solvent and heating, or by heating and thermally decomposing omega-iodide fluorine-containing ester in presence of a catalyst. EXAMPLE - Tetraglyme (50 ml) and potassium fluoride (in g) (5.1) taken in an autoclave were cooled in an ice bath. After performing vacuum substitution, 90% CF3COCOOMe (9) was prepared. Normal pressure release of the autoclave was carried after stirring for 30 minutes. Iodine (27.4) and ethylene fluoride (3) were added and stirred for 24 hours. The reaction solution was opened in cold water containing potassium hydrogen sulfite until the brown color was disappeared. The solution was filtered and liquid-separated. The aqueous layer was extracted by dichloromethane. The organic layer was recovered. omega-iodide fluorine-containing ester of formula, ICF2CF2OCF(CF3)CO2Me was obtained with a yield of 23.3% from the organic layer. Sodium hydroxide (16.3) was dissolved in a mixed solvent containing water (300 ml) and dioxane (100 ml). The formed ester compound was dropped into the solvent mixture at room temperature for 1 hour. The reaction mixture was heated, reacted at 80degreesC for 8 hours, and concentrated. The obtained solid was heated to 90degreesC after concentration for 12 hours. Sodium salt of the ester compound (163.3) (ICF2CF2OCF(CF3)COONa) was obtained with a yield of 99%. The hydrolyzed salt (41) and diethylene glycol dimethyl ether (100 ml) were taken in a flask, and inert gas was substituted inside the system. The temperature was increased to 95degreesC, and then cooled to room temperature. The reaction mixture was distilled and at 100degreesC, a compound having boiling point of 80degreesC began to distil. Distillation was continued and a fraction (30.8) containing vinyl ether of formula, ICF2CF2OCF=CF2 was obtained with a yield of 90% and purity of 95%. The obtained fraction was found to contain 5% of ICF2CF2OCHFCF3 as impurity.