Process for the preparation of fluoropolyoxyalkylenes having one end group -CH2OH and the other end group containing chlorine

A process to obtain fluoropolyoxyalkylenes having one end group containing one Cl atom and the other end group containing a methylol group, having structure:

• T—O—(CF2CF(CF3)O)n-1—(CF(CF3)O)m—CF2—CH2OH (I)
• wherein:
• T=C1-C3 perfluoroalkyl containing one Cl atom;
• n=an integer from 1 to 15;
• m/n=0-0.5;
• m+n being such to have a number average molecular weight in the range 280-4,000, preferably 280-1,000, said process comprising the following steps:
• a) the gradual addition, in inert gas atmosphere, of a mixture formed by an aprotic or protic solvent and a reducing agent selected from the metal hydrides class, to an ester precursor having the structure
• T—O—(CF2CF(CF3)O)n-1—(CF(CF3)O)m—CF2—COOR (II)
• wherein
• T, m, n have the above meaning;
• R represents a C1-C20 alkyl, aromatic, cycloalkyl or heterocyclic residue, said residues being optionally substituted,
• maintaining the reaction mixture under stirring at a temperature in the range 0°-20° C., preferably 5° C.-15° C.;
• b) hydrolysis of the reaction product obtained in step a) with an aqueous acid solution, with formation of an aqueous phase and of an organic one, and the subsequent separation from the organic phase of the compounds of structure (I) having one end group —CH2OH and the other one containing one chlorine atom.