(Per)fluoropolyether polymers

Abstract

The present invention relates to a novel process for the synthesis of (per)fluoropolyether polymers, to certain novel (per)fluoropolyether polymers. The present invention also relates to the use of the (per)fluoropolyether polymers thus obtained as intermediate compounds for the manufacture of further polymers suitable for use as lubricants, notably for magnetic recording media (MRM).

Claims

1. A process (P.sub.FH) for the synthesis of at least one polymer (FH), said polymer (FH) comprising a partially fluorinated polyether backbone having two chain ends, wherein said chain ends comprise at least one group selected from hydroxy group, allyl group and vinyl group, said process (P.sub.FH) comprising: (I) contacting at least one compound (F), wherein compound (F) is a perfluoro compound comprising at least two unsaturated groups selected from vinyl groups and allyl groups, with at least one compound (H), wherein compound (H) is a fully or partially hydrogenated compound comprising at least two hydroxy groups, to provide a polymer (FH), said polymer (FH) being characterized in that its backbone comprises recurring unit(s) derived from said at least one compound (F) alternately arranged with recurring unit(s) derived from said at least one compound (H).

2. The process according to claim 1, wherein said compound (F) complies with the following formula:
CF.sub.2═CF(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CF═CF.sub.2 wherein each of z and z* is independently 0 or 1; and R.sub.CF is a perfluoro alkylene chain comprising from 1 to 20 carbon atoms and optionally interrupted by one or more oxygen atoms; and/or said compound (H) complies with the following formula:
HO—(R.sub.H)—OH wherein R.sub.H is a linear or branched alkylene chain comprising from 2 to 12 carbon atoms, said alkyl chain optionally comprising one or more fluorine atoms(s) and optionally being interrupted by one or more oxygen atoms.

3. The process according to claim 1, wherein step (I) comprises adding, to said compound (F) and to said compound (H), one or more compound (F-mono), wherein compound (F-mono) is a compound comprising one unsaturated group selected from vinyl group and allyl group, and/or one compound (H-mono), wherein compound (H-mono) is a compound comprising one hydroxy group.

4. A polymer (FH*) comprising a partially fluorinated polyether backbone having two chain ends, wherein each of said chain ends comprises a group selected from hydroxy group, allyl group or vinyl group; and said backbone complies with structure (R.sub.FH-I):
—[CF.sub.2CFH(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO].sub.y—  (R.sub.FH-I) wherein each of z and z* is independently 0 or 1; R.sub.CF is a perfluoro alkylene chain comprising from 1 to 20 carbon atoms and optionally interrupted by one or more oxygen atoms; R.sub.H is a linear or branched alkylene chain comprising from 2 to 12 carbon atoms, said alkyl chain optionally comprising one or more fluorine atoms and optionally being interrupted by one or more oxygen atoms; and y is an integer, such that the average number molecular weight of the backbone of said polymer (FH) as determined by NMR analysis is from 306 to 50000.

5. The polymer (FH*) according to claim 4, wherein said polymer (FH*) is selected from polymers of formulae (FH.sub.b1) to (FH.sub.b3):
CF.sub.2═CF(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO—[CF.sub.2CFH(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO].sub.y—CF.sub.2CFH(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CF═CF.sub.2  (FH.sub.b1)
HO—R.sub.H—O[CF.sub.2CFH(CF.sub.2).sub.zO—R.sub.CF—O(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO].sub.y—H  (FH.sub.b2)
CF.sub.2═CF(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO—[CF.sub.2CFH(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO].sub.y—H  (FH.sub.b3) wherein each of z and z* is independently 0 or 1; R.sub.CF is a perfluoro alkylene chain comprising from 1 to 20 carbon atoms and optionally interrupted by one or more oxygen atoms; R.sub.H is a linear or branched alkylene chain comprising from 2 to 12 carbon atoms, said alkyl chain optionally comprising one or more fluorine atoms and optionally being interrupted by one or more oxygen atoms; and y is an integer, such that the average number molecular weight of the backbone of said polymer (FH) as determined by NMR analysis is from 306 to 50000.

6. A process (P.sub.PFPE) for the synthesis of a polymer (PFPE), said polymer (PFPE) comprising a perfluorinated polyether backbone having two chain ends, wherein each chain end comprises at least one group selected from —OC(═O)F and perfluorinated alkyl chain comprising from 2 to 3 carbon atoms, said process (P.sub.PFPE) comprising: (III) contacting at least one polymer (FH) or polymer (FH*) with a source of fluorine, to provide polymer (PFPE), wherein: polymer (FH) is a polymer comprising a partially fluorinated polyether backbone having two chain ends, wherein each of said chain ends comprise at least one group selected from hydroxy group, allyl group and vinyl group; and said backbone comprises recurring unit(s) derived from at least one compound (F), wherein compound (F) is a perfluoro compound comprising at least two unsaturated groups selected from vinyl groups and allyl groups, alternately arranged with recurring unit(s) derived from at least one compound (H), wherein compound (H) is a fully or partially hydrogenated compound comprising at least two hydroxy groups; and polymer (FH*) is a polymer comprising a partially fluorinated polyether backbone having two chain ends, wherein each of said chain ends comprises a group selected from hydroxy group, allyl group or vinyl group; and said backbone complies with structure (R.sub.FH-I):
—[CF.sub.2CFH(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO].sub.y—  (R.sub.FH-I) wherein each of z and z* is independently 0 or 1; R.sub.CF is a perfluoro alkylene chain comprising from 1 to 20 carbon atoms and optionally interrupted by one or more oxygen atoms; R.sub.H is a linear or branched alkylene chain comprising from 2 to 12 carbon atoms, said alkyl chain optionally comprising one or more fluorine atoms and optionally being interrupted by one or more oxygen atoms; and y is an integer, such that the average number molecular weight of the backbone of said polymer (FH) as determined by NMR analysis is from 306 to 50000.

7. The process according to claim 6, wherein said polymer (FH*) complies with formula (FH.sub.b1):
CF.sub.2═CF(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO—[CF.sub.2CFH(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2
—OR.sub.HO].sub.y—CF.sub.2CFH(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CF═CF.sub.2 wherein each of z and z* is independently 0 or 1; R.sub.CF is a perfluoro alkylene chain comprising from 1 to 20 carbon atoms and optionally interrupted by one or more oxygen atoms; R.sub.H is a linear or branched alkylene chain comprising from 2 to 12 carbon atoms, said alkyl chain optionally comprising one or more fluorine atoms and optionally being interrupted by one or more oxygen atoms; and y is an integer, such that the average number molecular weight of the backbone of said polymer (FH) as determined by NMR analysis is from 306 to 50000.

8. A perfluoropolyether polymer (PFPE), said polymer (PFPE) comprising a perfluoropolyether backbone having two chain ends, wherein: each chain end comprises at least one group selected from —OC(═O)F and perfluorinated alkyl chain comprising from 2 to 3 carbon atoms and said backbone complies with structure (R.sub.pf-I):
—[CF.sub.2CF.sub.2(CF.sub.2).sub.zOR.sub.CFO—(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.FO].sub.y—  (R.sub.pf-I) wherein R.sub.CF is a perfluoro alkyl chain comprising from 1 to 20 optionally interrupted by one or more oxygen atoms; R.sub.F is a perfluoro alkyl chain comprising from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; each of z and z* is independently 0 or 1; and y is an integer, such that the average number molecular weight of the backbone of said polymer (PFPE) as determined by NMR analysis is from 414 to 70 000; with the proviso that: when both z and z* are 0, at least one of said moiety R.sub.CF and said moiety R.sub.F is different from —CF.sub.2CF.sub.2— and —CF.sub.2CF.sub.2CF.sub.2CF.sub.2—; and when both z and z* are 1, at least one of moiety R.sub.CF and moiety R.sub.F is different from —CF.sub.2CF.sub.2CF.sub.2—.

9. A process (P.sub.PFPE-EST) for the synthesis of a polymer (PFPE.sub.EST), said polymer (PFPE.sub.EST) comprising a perfluorinated polyether backbone complying with formula (R.sub.pf-I):
—[CF.sub.2CF.sub.2(CF.sub.2).sub.zOR.sub.CFO—(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.FO].sub.y—  (R.sub.pf-I) wherein R.sub.CF is a perfluoro alkyl chain comprising from 1 to 20 optionally interrupted by one or more oxygen atoms; R.sub.F is a perfluoro alkyl chain comprising from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; each of z and z* is independently 0 or 1; and y is an integer, such that the average number molecular weight of the backbone of said polymer (PFPE) as determined by NMR analysis is from 414 to 70 000, and having two chain ends, wherein at least one chain end comprises at least one group of formula —C(═O)O—R.sub.alk, wherein R.sub.alk is a linear or branched alkyl chain comprising from 1 to 10 carbon atoms, said process (P.sub.PFPE-EST) comprising: (II) contacting said at least one polymer (FH) or polymer (FH*) , with at least one compound selected from F.sub.2C(═O), ClFC(═O), or BrFC(═O); (III) contacting the at least one polymer obtained after step (II) with a source of fluorine, to provide polymer (PFPE); and (IV) contacting the at least one polymer obtained in step (III) with at least one compound of formula R.sub.alk—OH, wherein R.sub.alk is a linear or branched alkyl chain comprising from 1 to 10 carbon atoms, to provide polymer (PFPE.sub.EST), wherein: polymer (FH) is a polymer comprising a partially fluorinated polyether backbone having two chain ends, wherein each of said chain ends comprise at least one group selected from hydroxy group, allyl group and vinyl group; and said backbone comprises recurring unit(s) derived from at least one compound (F), wherein compound (F) is a perfluoro compound comprising at least two unsaturated groups selected from vinyl groups and allyl groups, alternately arranged with recurring unit(s) derived from at least one compound (H), wherein compound (H) is a fully or partially hydrogenated compound comprising at least two hydroxy groups; and polymer (FH*) is a polymer comprising a partially fluorinated polyether backbone having two chain ends, wherein each of said chain ends comprises a group selected from hydroxy group, allyl group or vinyl group; and said backbone complies with structure (R.sub.FH-I):
—[CF.sub.2CFH(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO].sub.y—  (R.sub.FH-I) wherein each of z and z* is independently 0 or 1; R.sub.CF is a perfluoro alkylene chain comprising from 1 to 20 carbon atoms and optionally interrupted by one or more oxygen atoms; R.sub.H is a linear or branched alkylene chain comprising from 2 to 12 carbon atoms, said alkyl chain optionally comprising one or more fluorine atoms and optionally being interrupted by one or more oxygen atoms; and y is an integer, such that the average number molecular weight of the backbone of said polymer (FH) as determined by NMR analysis is from 306 to 50000.

10. The process according to claim 9, wherein said polymer (FH*) is selected from polymers of the following formulae:
HO—R.sub.H—O[CF.sub.2CFH(CF.sub.2).sub.zO—R.sub.CF—O(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO].sub.y—H  (FH.sub.b2)
CF.sub.2═CF(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO—[CF.sub.2CFH(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CFHCF.sub.2—OR.sub.HO].sub.y—H  (FH.sub.b3) wherein each of z and z* is independently 0 or 1; R.sub.CF is a perfluoro alkylene chain comprising from 1 to 20 carbon atoms and optionally interrupted by one or more oxygen atoms; R.sub.H is a linear or branched alkylene chain comprising from 2 to 12 carbon atoms, said alkyl chain optionally comprising one or more fluorine atoms and optionally being interrupted by one or more oxygen atoms; and y is an integer, such that the average number molecular weight of the backbone of said polymer (FH) as determined by NMR analysis is from 306 to 50000.

11. A polymer (PFPE.sub.EST) comprising a perfluoropolyether backbone complying with formula (R.sub.pf-I):
—[CF.sub.2CF.sub.2(CF.sub.2).sub.zoR.sub.CFo—(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.FO].sub.y—  (R.sub.pf-I) wherein R.sub.CF is a perfluoro alkyl chain comprising from 1 to 20 optionally interrupted by one or more oxygen atoms; R.sub.F is a perfluoro alkyl chain comprising from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; each of z and z* is independently 0 or 1; and y is an integer, such that the average number molecular weight of the backbone of said polymer (PFPE) as determined by NMR analysis is from 414 to 70 000, and having two chain ends, wherein at least one chain end, and preferably both said chain comprises at least one group —C(═O)O—R.sub.alk, wherein R.sub.alk is a linear or branched alkyl chain comprising from 1 to 10 carbon atoms.

12. The polymer (PFPE.sub.EST) according to claim 11, wherein said polymer (PFPE.sub.EST) is selected from polymers of formulae:
R.sub.alkO(O═)C—R.sub.F—[OCF.sub.2CF.sub.2(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.F].sub.y—C(═O)OR.sub.alk  (PFPE.sub.EST-b2)
CF.sub.3CF.sub.2(CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.F—[OCF.sub.2CF.sub.2CF.sub.2).sub.zOR.sub.CFO(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.F].sub.y—C(═)OR.sub.alk  (PFPE.sub.EST-b3) wherein R.sub.CF is a perfluoro alkyl chain comprising from 1 to 20 optionally interrupted by one or more oxygen atoms; R.sub.F is a perfluoro alkyl chain comprising from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; each of z and z* is independently 0 or 1; y is an integer, such that the average number molecular weight of the backbone of said polymer (PFPE) as determined by NMR analysis is from 414 to 70 000; and R.sub.alk is a linear or branched alkyl chain comprising from 1 to 10 carbon atoms.

13. A polymer (PFPE.sub.OH) comprising a perfluoropolyether backbone complying with formula (R.sub.pf-I):
—[CF.sub.2CF.sub.2(CF.sub.2).sub.zOR.sub.CFO—(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.FO].sub.y—  (R.sub.pf-I) wherein R.sub.CF is a perfluoro alkyl chain comprising from 1 to 20 optionally interrupted by one or more oxygen atoms; R.sub.F is a perfluoro alkyl chain comprising from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; each of z and z* is independently 0 or 1; and y is an integer, such that the average number molecular weight of the backbone of said polymer (PFPE) as determined by NMR analysis is from 414 to 70 000, and having two chain ends, wherein at least one chain end comprises a group of formula —CF.sub.2CH.sub.2OH, with the proviso that the backbone of said polymer (PFPE.sub.OH) is different from —[(C.sub.2F.sub.4O).sub.a(C.sub.4F.sub.8O).sub.b].sub.y— wherein each of a, b and y is an integer higher than 1.

14. A polymer (PFPE.sub.OH-X) comprising a perfluoropolyether backbone complying with formula (R.sub.pf-I):
—[CF.sub.2CF.sub.2(CF.sub.2).sub.zOR.sub.CFO—(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.FO].sub.y—  (R.sub.pf-I) wherein R.sub.CF is a perfluoro alkyl chain comprising from 1 to 20 optionally interrupted by one or more oxygen atoms; R.sub.F is a perfluoro alkyl chain comprising from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; each of z and z* is independently 0 or 1; and y is an integer, such that the average number molecular weight of the backbone of said polymer (PFPE) as determined by NMR analysis is from 414 to 70 000, and having two chain ends, wherein at least one chain end comprises a group of formula —CF.sub.2CH.sub.2O—R.sup.1, wherein R.sup.1 is a linear or branched alkyl chain comprising from 1 to 16 carbon atoms and substituted with at least 2 groups —OH.

15. The polymer (PFPE.sub.OH-X) according to 14, wherein both said chain ends comprise a group complying with one of the following formulae:
—CF.sub.2CH.sub.2O—CH.sub.2CH(OH)CH.sub.2OH  (PFPE.sub.OH-X1)
—CF.sub.2CH.sub.2O—CH.sub.2CH(OH)CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH  (PFPE.sub.OH-X2).

16. A polymer (PFPE.sub.OH-MD) complying with the following formula
C.sub.e-B-A-B-C.sub.e wherein: each C.sub.e is a group of formula —CF.sub.2CH.sub.2O—R.sup.1, wherein R.sup.1 is a hydrogen atom, linear or branched alkyl chain comprising from 1 to 16 carbon atoms and substituted with at least 2 groups —OH; each B is a group complying with formula (R.sub.pf-I):
—[CF.sub.2CF.sub.2(CF.sub.2).sub.zOR.sub.CFO—(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.FO].sub.y—  (R.sub.pf-I) wherein R.sub.CF is a perfluoro alkyl chain comprising from 1 to 20 optionally interrupted by one or more oxygen atoms; R.sub.F is a perfluoro alkyl chain comprising from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; each of z and z* is independently 0 or 1; and y is an integer, such that the average number molecular weight of the backbone of said polymer (PFPE) as determined by NMR analysis is from 414 to 70 000; and A is a divalent alkyl chain comprising from 3 to 20 carbon atoms, said alkyl chain being substituted with at least one —OH group(s) and being optionally substituted with at least one fluorine atom.

17. A method for lubricating a magnetic recording media (MRM), said method comprising providing a magnetic recording media (MRM) comprising at least one magnetic layer, optionally covered by at least one carbon overcoat, and applying at least one of polymer (PFPE.sub.OH), polymer (PFPE.sub.OH-X) and/or polymer (PFPE.sub.OH-MD) onto said magnetic layer or onto said carbon overcoat, wherein: polymer (PFPE.sub.OH) is a polymer comprising a perfluoropolyether backbone complying with formula (R.sub.pf-I) and having two chain ends, wherein at least one chain end comprises a group of formula —CF.sub.2CH.sub.2OH, with the proviso that the backbone of said polymer (PFPE.sub.OH) is different from —[(C.sub.2F.sub.4O).sub.a(C.sub.4F.sub.8O).sub.b].sub.x— wherein each of a, b and y is an integer higher than 1; polymer (PFPE.sub.OH-X) is a polymer comprising a perfluoropolyether backbone complying with formula (R.sub.d-I) and having two chain ends, wherein at least one chain end comprises a group of formula —CF.sub.2CH.sub.2O—R.sup.1, wherein R.sup.1 is a linear or branched alkyl chain comprising from 1 to 16 carbon atoms and substituted with at least 2 groups —OH; and polymer (PFPE.sub.OH-MD) is a polymer complying with the following formula
C.sub.e-B-A-B-C.sub.e wherein: each C.sub.e is a group of formula —CF.sub.2CH.sub.2O—R.sup.1, wherein R.sup.1 is a hydrogen atom, linear or branched alkyl chain comprising from 1 to 16 carbon atoms and substituted with at least 2 groups —OH; each B is a group complying with formula (R.sub.pf-I); and A is a divalent alkyl chain comprising from 3 to 20 carbon atoms, said alkyl chain being substituted with at least one —OH group(s) and being optionally substituted with at least one fluorine atom, and wherein formula (R.sub.pf-I) is:
—[CF.sub.2CF.sub.2(CF.sub.2).sub.zOR.sub.CFO—(CF.sub.2).sub.z*CF.sub.2CF.sub.2—OR.sub.FO].sub.y—  (R.sub.pf-I) wherein R.sub.CF is a perfluoro alkyl chain comprising from 1 to 20 optionally interrupted by one or more oxygen atoms; R.sub.F is a perfluoro alkyl chain comprising from 2 to 12 carbon atoms, optionally interrupted by one or more oxygen atoms; each of z and z* is independently 0 or 1; and y is an integer, such that the average number molecular weight of the backbone of said polymer (PFPE) as determined by NMR analysis is from 414 to 70 000.

Description

EXAMPLE 1

(1) Step (a): Synthesis of HO(CH.sub.2).sub.4OCF.sub.2CFHO(CF.sub.2).sub.4OCFHCF.sub.2O(CH.sub.2).sub.4OH

(2) A three neck round bottom flask with magnetic stirring, temperature probe and reflux condenser was charged with 5.76 g of NaOH and 227.76 g of 1,4-butanediol. The mixture was heated at 70° C. under stirring till complete dissolution of sodium hydroxide. Then, the solution was cooled at 40° C. and 50 g of CF.sub.2═CFO(CF.sub.2).sub.4OCF═CF.sub.2 was added dropwise. The resulting mixture was held at 40° C. under stirring for six hours, till complete conversion of perfluoro bis-vinylether. The crude was extracted with 80 ml of water and 80 ml of CH.sub.2Cl.sub.2; the aqueous phase was extracted again with 120 ml of fresh CH.sub.2Cl.sub.2 and the two organic phases were collected and extracted with brine (80 ml). The organic phase was separated, treated with anhydrous Na.sub.2SO.sub.4, filtered and solvent was evaporated under reduced pressure to obtain 57.7 g of a mixture containing:
HO(CH.sub.2).sub.4[OCF.sub.2CFHO(CF.sub.2).sub.4OCFHCF.sub.2O(CH.sub.2).sub.4].sub.nOH 78% with n=1 15% with n=2 4% with n=3 3% with n=4
Step (b): synthesis of (EtOC(O)CF.sub.2CF.sub.2CF.sub.2OCF.sub.2CF.sub.2OCF.sub.2CF.sub.2-).sub.2 and Higher MW Homologous

(3) 10.5 g of the mixture of alcohols prepared in step (a) were dissolved in 92.4 g of 1,2,3,4-tetrachloro hexafluorobutane and loaded in a 250 ml stainless steel mechanically stirred reactor kept at the temperature of +20° C. by an external cooling bath. 2.0 NI/h of COF.sub.2 (synthesized in a tubular reactor mixing 2.0 NI/h of F2, 3.0 NI/h of CO and 4.0 NI/h of He) were fed to the reactor to convert all —OH groups to the corresponding —OC(O)F groups; the completion of the reaction is verified by IR and GC online analysis (no conversion of the COF.sub.2 fed to the reactor).

(4) Then, 2.0 NI/h of F.sub.2 diluted in 8.0 NI/h of He were fed to the reactor to convert the hydrogen atoms present in the backbone of the formates; fluorine conversion was determined by GC online analysis: when it dropped below 60% fluorine flow was increased to 2.3 NI/h while introducing, by a second inlet tube, 0.3 NI/h of C3F6 (diluted in 1.5 NI/h of He); with this fluorolefin activation of elemental fluorine (according to U.S. Pat. No. 8,742,142 (SOLVAY SOLEXIS S.P.A.) it was possible to maintain a high fluorine conversion till complete perfluorination (pointed out by sudden fall to zero of fluorine conversion determined by GC).

(5) The raw mixture was transferred in a PFA round bottom flask containing 20 g of anhydrous ethanol and then all volatile compounds (HF, CH.sub.3CH.sub.2OC(O)F, CH.sub.3CH.sub.2OH in excess and the solvent) were evaporated at low pressure and at a temperature not exceeding 70° C. 15.6 g of an oily transparent uncoloured liquid were obtained and analysed by IR, NMR and GPC confirming the desired structure.

(6) Step (c): Synthesis of HOCH.sub.2CF.sub.2(CF.sub.2).sub.2OCF.sub.2CF.sub.2OCF.sub.2CF.sub.2CF.sub.2CF.sub.2OCF.sub.2CF.sub.2O(CF.sub.2).sub.2CF.sub.2CH.sub.2OH

(7) The resulting mixture of diethyl-ester polymers from step (b) was fractionated through vacuum distillation to separate the first component which was then subjected to chemical reduction with NaBH.sub.4 to afford the corresponding diol as confirmed by NMR.

EXAMPLE 2

(8) Step (a): Synthesis of HO(CH.sub.2).sub.3[OCF.sub.2CFHO(CF.sub.2).sub.3OCFHCF.sub.2O(CH.sub.2).sub.3].sub.nOH

(9) A three neck round bottom flask with magnetic stirring, temperature probe and reflux condenser was charged with 6.69 g of NaOH, 82.40 g of 1,3-propanediol and 200 ml of acetonitrile. The mixture was heated at 40° C. under stirring till complete dissolution of sodium hydroxide. Then 107.40 g of CF.sub.2═CFO(CF.sub.2).sub.3OCF═CF.sub.2 were added dropwise. The resulting mixture was held at 40° C. under stirring for six hours, till complete conversion of perfluoro-bis-vinylether. The crude was extracted with 200 ml of water and 200 ml of CH.sub.2Cl.sub.2; the aqueous phase was extracted again with 200 ml of fresh CH.sub.2Cl.sub.2 and the two organic phases were collected and extracted with brine (200 ml). The organic phase was separated, treated with anhydrous Na.sub.2SO.sub.4, filtered and solvent was evaporated under reduced pressure to obtain a mixture containing: 33% of HO(CH.sub.2).sub.3OCF.sub.2CFHO(CF.sub.2).sub.3OCFHCF.sub.2O(CH.sub.2).sub.3OH in admixture with a cyclic ether as side product obtained from the intramolecular reaction between the hydroxy group and the vinyl group in the product of formula HO(CH.sub.2).sub.3O—CF.sub.2CFHO(CF.sub.2).sub.3OCF═CF.sub.2; 23% of HO(CH.sub.2).sub.3[OCF.sub.2CFHO(CF.sub.2).sub.3OCFHCF.sub.2O(CH.sub.2).sub.3].sub.nOH with n=2, 23% of the compound with n=3 and 21% of the compound with mixture with n=4 or 5 as a admixture.

(10) Step (b): Synthesis of (EtOC(O)CF.sub.2CF.sub.2OCF.sub.2CF.sub.2OCF.sub.2).sub.2CF.sub.2 and higher MW Homologous

(11) The same procedure described in step (b) of Example 1 was followed but starting from 10.7 g of the mixture of alcohols obtained in step (a) of Example 2. 15.7 g of the final diethyl-ester polymer were obtained.

(12) Step (c): Synthesis of Polymers Having Formulae HOCH.sub.2CF.sub.2CF.sub.2OCF.sub.2CF.sub.2O[(CF.sub.2CF.sub.2CF.sub.2O)(CF.sub.2CF.sub.2O)].sub.3CF.sub.2CF.sub.2CH.sub.2OH and HOCH.sub.2CF.sub.2CF.sub.2OCF.sub.2CF.sub.2O[(CF.sub.2CF.sub.2CF.sub.2O)(CF.sub.2CF.sub.2O)].sub.5CF.sub.2CF.sub.2CH.sub.2OH

(13) The resulting mixture of diethyl-ester polymers from step (b) was fractionated through vacuum distillation to separate the second and the third components which were then subjected to chemical reduction with NaBH4 to afford the corresponding diols as confirmed by NMR.

(14) Step (d): Synthesis of Polymers Having Formulae HOCH.sub.2CH(OH)CH.sub.2OCH.sub.2CF.sub.2CF.sub.2OCF.sub.2CF.sub.2O[(CF.sub.2CF.sub.2CF.sub.2O)(CF.sub.2CF.sub.2O)].sub.3CF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH

(15) The diol HOCH.sub.2CF.sub.2CF.sub.2OCF.sub.2CF.sub.2O[(CF.sub.2CF.sub.2CF.sub.2O)—(CF.sub.2CF.sub.2O)].sub.3C—F.sub.2CF.sub.2— —CH.sub.2OH prepared in step (c) was reacted with the mesyl derivative of Solketal following the procedure described in U.S. Pat. No. 8,513,471 (SOLVAY SOLEXIS S.P.A.) to provide the corresponding tetraol as confirmed by NMR analysis.

EXAMPLE 3

(16) Step (a): Synthesis of [HO(CH.sub.2).sub.4OCF.sub.2CFHOCF.sub.2OCF.sub.2CF.sub.2].sub.2O

(17) A three neck round bottom flask with magnetic stirring, temperature probe and reflux condenser was charged with 3.95 g of NaOH, 178 g of 1,4-butanediol and 80 ml of HCF.sub.2CF.sub.2OCH.sub.2CH.sub.2OCF.sub.2CF.sub.2H. The mixture was heated at 70° C. under stirring till complete dissolution of sodium hydroxide, then 54 g of [CF.sub.2═CFOCF.sub.2OCF.sub.2CF.sub.2].sub.2O were added dropwise. The resulting mixture was held at 70° C. under stirring for three hours, till complete conversion of perfluoro-bis-vinylether. The crude was extracted with 150 ml of water; the organic layer was separated and solvent was evaporated at 100° C. under reduced pressure. The residual viscous oil was filtered to obtain 33 g of a mixture containing: HO(CH.sub.2).sub.4[OCF.sub.2CFHOCF.sub.2O(CF.sub.2).sub.2O(CF.sub.2).sub.2OCF.sub.2OCFHCF.sub.2O(CH.sub.2).sub.4].sub.nOH with n from 1 to 4.

(18) Step (b): Synthesis of (EtOC(O)CF.sub.2CF.sub.2CF.sub.2OCF.sub.2CF.sub.2OCF.sub.2OCF.sub.2CF.sub.2—).sub.2O and Higher MW Homologous

(19) The same procedure described in step (b) of Example 1 was followed but starting from 10.2 g of the mixture of alcohols obtained in step (a) of Example 3.

(20) 15.0 g of the final diethyl-ester polymers were obtained.

EXAMPLE 4

(21) Step (a): Synthesis of HO(CH.sub.2).sub.4[OCF.sub.2CFHO(CF.sub.2).sub.3OCFHCF.sub.2O(CH.sub.2).sub.4].sub.nOH

(22) A three neck round bottom flask with magnetic stirring, temperature probe and reflux condenser was charged with 8.7 g of NaOH, 78.12 g of 1,4-butanediol and 300 ml of acetonitrile. The mixture was heated at 40° C. under stirring for three hours and, then, 147.91 g of CF.sub.2═CFO(CF.sub.2).sub.3OCF═CF.sub.2 were added drop wise. The resulting mixture was held at 40° C. under stirring for two hours, till complete conversion of perfluoro bis-vinylether. Acetonitrile was then evaporated at 60° C. under reduced pressure and the crude was extracted with 300 ml of water and 300 ml of CH.sub.2Cl.sub.2. The aqueous phase was extracted again with 300 ml of fresh CH.sub.2Cl.sub.2 and the two organic phases were collected and extracted with brine (200 ml). The organic phase was separated, treated with anhydrous Na.sub.2SO.sub.4, filtered and solvent was evaporated under reduced pressure to obtain 167.07 g of a mixture containing:

(23) HO(CH.sub.2).sub.4OCF.sub.2CFHO(CF.sub.2).sub.3OCFHCF.sub.2O(CH.sub.2).sub.4OH in admixture with a cyclic ether as side product obtained from the intramolecular reaction between the hydroxy group and the vinyl group in the product of formula
HO(CH.sub.2).sub.4O—CF.sub.2CFHO(CF.sub.2).sub.3OCF═CF.sub.2;
HO(CH.sub.2).sub.4[OCF.sub.2CFHO(CF.sub.2).sub.3OCFHCF.sub.2O(CH.sub.2).sub.4].sub.nOH with n=2, 3 and a mixture with n=4 or 5.
Step (b): Synthesis of (EtOC(O)CF.sub.2CF.sub.2CF.sub.2OCF.sub.2CF.sub.2OCF.sub.2).sub.2CF.sub.2 and Higher MW Homologous

(24) The same procedure described in step (b) of Example 1 was followed but starting from 10.9 g of the mixture of alcohols obtained in step (a) of Example 4.

(25) 16.0 g of the final diethyl-ester polymers were obtained.