by nitrogen and the temperature was lowered to 0 u00b0 5 u00b0 c then ethylene oxide 44 g 1 mol was dropwise added thereto the resultant mixture was heated to 100 u00b0 c followed by stirring for 18 hours from the reaction mixture the catalyst was eliminated to give an objective compound of the formula str17 wherein n is 14 in average and m is 6 in average in the same manner as above but using 34 claytox 157fs 34 perfluoroalkylpolyether carboxylic acid grade m manufactured by dupont 90 g 0 02 mol in place of 34 claytox 157fs 34 grade l 50 g 0 02 mol to give an objective compound of the formula str18 wherein n is 26 in average and m is 6 in average preparation of the compound i as employed in examples 2 8 10 and 16 into a flask the reduction product of 34 claytox 157fs 34 grade l as obtained in reference example 1 50 g 0 02 mol was charged and xylene 200 g and 34 flutec pp3 34 a fluorine containing solvent manufactured by isc chemical u k 300 g were added thereto the resultant mixture was heated at 50 u00b0 c during which metallic sodium 0 6 g 0 26 mol was portionwise added thereto followed by stirring to give an alkalized product of the formula str19 wherein n is 14 in average to 550 g of the thus obtaind reaction mixture comprising 0 02 mol of the alkalized product tetraethylene glycol monomethyl ether monoiodide ch 3 o ch 2 ch 2 o 3 ch 2 ch 2 i 1 7 g 0 005 mol was added and the resultant mixture was heated.