CYCLOPHOSPHAZENE DERIVATIVES

Abstract

The present invention relates to a phosphazene compound [compound (L)] comprising a cyclophosphazene central core wherein each phosphorus atom of said core bears a substituent independently selected from: a) a chain (A), said chain (A) comprising a (per)fluoropolyether chain [chain (R.sub.f)], one or more aromatic or heteroaromatic moieties [moiety/ies (Ar.sup.m)] and, optionally, one or more hydroxy groups and b) a chain (B), said chain (B) comprising a (per)fluoropolyether chain [chain (R.sub.f)] and one or more hydroxy groups with the proviso that at least one phosphorous atom of the central core is substituted with chain (A) and to mixtures of compounds (L). The invention further relates to methods for preparing compounds (L), to lubricant compositions comprising compounds (L) and to methods for lubricating magnetic recording media comprising applying a compound (L) or a lubricant compositions containing them to the surface of said medium.

Claims

1. A compound (L) comprising a cyclophosphazene central core wherein each phosphorus atom of said core bears substituents independently selected from: a) a chain (A), said chain (A) comprising a (per)fluoropolyether chain [chain (R.sub.f)], one or more aromatic or heteroaromatic moieties [moiety/ies (Ar.sup.m)] and, optionally, one or more hydroxy groups and b) a chain (B), said chain (B) comprising a (per)fluoropolyether chain [chain (R.sub.f)] and one or more hydroxy groups; with the proviso that at least one phosphorous atom of the central core is substituted with chain (A).

2. The compound according to claim 1 wherein chain (R.sub.f) in chains (A) and (B) is a fully or partially fluorinated polyoxyalkylene chain that comprises repeating units R.sup.∘, said repeating units being independently selected from the group consisting of: (i) —CFXO—, wherein X is F or CF.sub.3, (ii) —CFXCFXO—, wherein X, equal or different at each occurrence, is F or CF.sub.3, with the proviso that at least one of X is —F, (iii) —CF.sub.2CF.sub.2CW.sub.2O—, wherein each of W, equal or different from each other, are F, Cl, H, (iv) —CF.sub.2CF.sub.2CF.sub.2CF.sub.2O—, and (v) —(CF.sub.2).sub.j—CFZ—O— wherein j is an integer from 0 to 3 and Z is a group of general formula —OR.sub.f′T, wherein R.sub.f′ is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being selected from: —CFXO—, —CF.sub.2CFXO—, —CF.sub.2CF.sub.2CF.sub.2O—, —CF.sub.2CF.sub.2CF.sub.2CF.sub.2O—, with each of each of X being independently F or CF.sub.3 and T being a C.sub.1-C.sub.3 perfluoroalkyl group.

3. The compound according to claim 2 wherein chain (R.sub.f) complies with formula (R.sub.f-III) here below:
—(CF.sub.2CF.sub.2O).sub.a1(CF.sub.2O).sub.a2—  (R.sub.f-III) wherein: a1, and a2 are integers >0 such that the number average molecular weight is between 400 and 10,000, with the ratio a2/a1 being comprised between 0.1 and 10.

4. The compound according to claim 1 complying with formula (L-1) below: ##STR00009## wherein: x and y are 0, 1 or 2, with the proviso that x+y=2; z is an integer of at least 3; chain (A) and chain (B) are as defined in claim 1 with the proviso that at least one chain (A) is present in formula (L-1).

5. The compound according to claim 4 wherein z is 3 or 4.

6. The compound according to claim 4 wherein chain (A) complies with formula (A-1) below:
-G*-O—R.sub.f-E*  (A-1) wherein: G* is a divalent bridging group, partially fluorinated and containing one or more oxygen atoms, said group optionally comprising one or more hydroxy groups; R.sub.f is a (per)fluoropolyether chain; and E* represents a hydrocarbon group, partially fluorinated and containing one or more oxygen atoms, said group optionally comprising one or more hydroxy groups and wherein either (G*) or (E*) comprises the one or more aromatic or heteroaromatic moiety (Ar.sup.m).

7. The compound according to claim 6 wherein (G*) is selected from formulae (i*)-(vii*) below:
—(OCH.sub.2CH.sub.2).sub.nOCH.sub.2XFC—;  (i*)
—[OCH(CH.sub.3)CH.sub.2)].sub.nOCH.sub.2XFC—;  (ii*)
—(OCH.sub.2CH.sub.2).sub.nOCH.sub.2CF.sub.2CF.sub.2—;  (iii*)
—[OCH.sub.2CH(OH)CH.sub.2].sub.n′OCH.sub.2XFC—;  (iv*)
—[OCH(CH.sub.2OH)CH.sub.2].sub.n′OCH.sub.2XFC—;  (v*)
—[OCH.sub.2CH(OH)CH.sub.2).sub.n′OCH.sub.2CF.sub.2CF.sub.2—; and  (vi*)
—[OCH(CH.sub.2OH)CH.sub.2].sub.n′OCH.sub.2CF.sub.2CF.sub.2—  (vii*) wherein X is F or CF.sub.3, n ranges from 0 to 5 and n′ ranges from 1 to 3 and wherein (E*) is selected from formulae (viii*)-(xii*) below:
—CFXCH.sub.2O(CH.sub.2CH.sub.2O).sub.n(CH.sub.2).sub.pAr.sup.m;  (viii*)
—CFXCH.sub.2O[CH.sub.2CH(CH.sub.3)O].sub.n(CH.sub.2).sub.pAr.sup.m;  (ix*)
—CF.sub.2CF.sub.2CH.sub.2O(CH.sub.2CH.sub.2O).sub.n(CH.sub.2).sub.pAr.sup.m;  (x*)
—CFXCH.sub.2O[CH.sub.2CH(OH)CH.sub.2O).sub.n(CH.sub.2].sub.pAr.sup.m and  (xi*)
—CF.sub.2CF.sub.2CH.sub.2O[CH.sub.2CH(OH)CH.sub.2O].sub.n(CH.sub.2).sub.pAr.sup.m,  (xii*) wherein: X is F or CF.sub.3, n and n′ are as defined above, p is 0 or 1 and (Ar.sup.m) is an aromatic or heteroaromatic moiety.

8. The compound according to claim 7 wherein (Ar.sup.m) is phenyl or pyridyl bearing one or more substituents independently selected from fluorine, trifluoromethyl and nitro.

9. The compound according to claim 4 wherein chain (B) complies with formula (B-1) below:
-G**-O—R.sub.f-E**  (B-1) wherein: G** is a divalent bridging group, partially fluorinated and containing one or more oxygen atoms, said group optionally comprising one or more hydroxy groups; R.sub.f is a (per)fluoropolyether chain and E** represents a hydrocarbon group, partially fluorinated and optionally containing one or more oxygen atoms, said group comprising one or more hydroxy groups.

10. The compound according to claim 9 wherein (G**) is selected from formulae (i*)-(vii*) below:
—(OCH.sub.2CH.sub.2).sub.nOCH.sub.2XFC—;  (i*)
—[OCH(CH.sub.3)CH.sub.2)].sub.nOCH.sub.2XFC—;  (ii*)
—(OCH.sub.2CH.sub.2).sub.nOCH.sub.2CF.sub.2CF.sub.2—;  (iii*)
—[OCH.sub.2CH(OH)CH.sub.2].sub.n′OCH.sub.2XFC—;  (iv*)
—[OCH(CH.sub.2OH)CH.sub.2].sub.n′OCH.sub.2XFC—;  (v*)
—[OCH.sub.2CH(OH)CH.sub.2).sub.n′OCH.sub.2CF.sub.2CF.sub.2—; and  (vi*)
—[OCH(CH.sub.2OH)CH.sub.2].sub.n′OCH.sub.2CF.sub.2CF.sub.2—  (vii*) wherein X is F or CF.sub.3, n ranges from 0 to 5 and n′ ranges from 1 to 3 and wherein (E**) is selected from formulae (viii**)-(xii**) below:
—CFXCH.sub.2O(CH.sub.2CH.sub.2O).sub.nH;  (viii**)
—CFXCH.sub.2O[CH.sub.2CH(CH.sub.3)O].sub.nH;  (ix**)
—CF.sub.2CF.sub.2CH.sub.2O(CH.sub.2CH.sub.2O).sub.nH;  (x**)
—CFXCH.sub.2O[CH.sub.2CH(OH)CH.sub.2O].sub.n′H and  (xi**)
—CF.sub.2CF.sub.2CH.sub.2O[CH.sub.2CH(OH)CH.sub.2O].sub.n′H,  (xii**) wherein X is F or CF.sub.3 and n and n′ are as defined above.

11. The compound according to claim 6 wherein: (G*) and (G**) are selected from: formula (i*) —(OCH.sub.2CH.sub.2).sub.nOCH.sub.2XFC—, wherein X is F and n is selected from 0, 1 and 2; and formula (iv*) —[OCH.sub.2CH(OH)CH.sub.2].sub.n′OCH.sub.2XFC—, wherein X is F and n′ is 1; (E*) is selected from: formula (viii*) —CFXCH.sub.2O(CH.sub.2CH.sub.2O).sub.n(CH.sub.2).sub.pAr.sup.m, wherein X is F, n is selected from 0, 1 and 2, p is 0 and (Ar.sup.m) is phenyl or pyridyl bearing one or more substituents independently selected from fluorine, trifluoromethyl and nitro; and formula (xi*) —CFXCH.sub.2O[CH.sub.2CH(OH)CH.sub.2O].sub.n(CH.sub.2).sub.pAr.sup.m, wherein X is F, n′ is 1, p is 0 and (Ar.sup.m) is phenyl or pyridyl bearing one or more substituents independently selected from fluorine, trifluoromethyl and nitro; and (E**) is selected from formula (viii**) —CFXCH.sub.2O(CH.sub.2CH.sub.2O).sub.nH, wherein X is F and n is selected from 0, 1 and 2; and formula (xi**) —CFXCH.sub.2O[CH.sub.2CH(OH)CH.sub.2O].sub.n′H, wherein X is F and n′ is 1.

12. A mixture comprising a compound of claim 1 and one or more compounds comprising a cyclophosphazene central core wherein each phosphorus atom of said core bears substituents independently selected from: a) a chain (A), said chain (A) comprising a (per)fluoropolyether chain [chain (R.sub.f)], one or more aromatic or heteroaromatic moieties (Ar.sup.m) and, optionally, one or more hydroxy groups and b) a chain (B), said chain (B) comprising a (per)fluoropolyether chain [chain (R.sub.f)] and one or more hydroxy groups and c) at least one chain (B′), said chain (B′) comprising a (per)fluoropolyether chain (R.sub.f), wherein both ends of chain (R.sub.f) are bound either to a same phosphorus atom of the cyclophosphazene ring or to two different phosphorus atoms of the cyclophosphazene ring via a bridging group (G), said group (G) comprising one or more aromatic or heteroatomatic moieties and/or one or more hydroxy groups, with the proviso that at least one chain (A), or at least one chain (B′) wherein bridging group (G) comprises one or more aromatic or heteroaromatic moieties, (Ar.sup.m) is present.

13. A lubricant composition comprising one or more compounds of claim 1.

14. A method for lubricating sliding or moving parts of a magnetic recording medium comprising applying to said parts the composition of claim 13.

15. A magnetic recording medium comprising a sliding or moving part having applied thereto the composition of claim 13.

Description

EXPERIMENTAL SECTION

Materials

[0185] The PFPE-Pol used in Examples 1 and 2 was obtained by multiple distillation and purification of commercially available products from Solvay Specialty Polymers Italy.

[0186] 2-chloro-5-(trifluoromethyl)pyridine, 2-chloro-2,4-dinitrobenzene, potassium tert-butoxide, tert-butyl alcohol (TBA), HCl, KOH, isobutyl alcohol, potassium carbonate, tetramethylammonium hydroxide and acetonitrile were obtained from Sigma-Aldrich® and were used as received.

[0187] Hexachlocyclotriphosphazene (HCP) was purchased from Strem Chemicals, Inc.

[0188] 1,3-hexafluoroxylene (HFX) was obtained from Miteni S.p.A. and was used as received.

Methods

NMR Spectroscopy

[0189] .sup.31P, .sup.19F, .sup.1H and .sup.13C NMR spectra were recorded at 25° C. using an Agilent® System 500 operating at 121.40 MHz for .sup.31P, 470.30 MHz for .sup.19F, 499.86 MHz for .sup.1H and 125.70 MHz for .sup.13C. Samples have been acquired dissolved in a mixture 3:1 v/v CFC113/Methanol-d.sub.4 (CD.sub.3OD) 99.9 atom % D at about 10% w/w.

Definition and Determination of the Ratio R

[0190] R is defined as the ratio between ═P—OCH.sub.2— groups (P is the phosphorus atom in the cyclophosphazene ring) and the overall amount of free end groups.

[0191] The estimation of ratio R has been performed by using fluorine, proton and optionally carbon spectra which show distinct peaks for ═POCH.sub.2— and free end groups.

Gel Permeation Chromatography (GPC)

[0192] The molecular weight distribution and the polydispersity index (Mw/Mn) were determined by Gel Permeation Chromatography (GPC). The GPC system was equipped with a Waters HPLC 515 pump, three PL-Gel columns (one Mixed-D and two Mixed-E) and a Waters 2414 refractive index detector. The columns and detector were thermostated at 35° C. The mobile phase was a mixture of 1,3-bis(trifluoromethyl)benzene and isopropanol (80/20 vol.), fluxed at 1.0 ml/min. Samples were dissolved at 1% wt/vol concentration in the mobile phase under stirring at room temperature until complete dissolution (about 1 hour). For the analysis 200 μl of the solution were injected. The calibration curve was obtained by using eight Fomblin® Z DOL PFPE narrow fractions with molecular weights known from NMR analysis and falling in the range 461-6878. Acquisition and the calculations were performed using Waters Empower software.

Fractionation with Supercritical CO.sub.2 (scCO.sub.2)

[0193] Fractionation with scCO.sub.2 was carried out using a 300 ml SFT-150 Supercritical CO.sub.2 Extraction System.

Example 1

[0194] Step (a)—Preparation of a mixture (M-1) [reaction of a PFPE-Pol with 2-chloro-5-(trifluoromethyl)pyridine] (target conversion=10%)

[0195] 1000.0 g of a PFPE-Pol of formula HO—CH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O).sub.a1(CF.sub.2O).sub.a2CF.sub.2CH.sub.2—OH

[0196] (MW=925 g/mol, a1/a2=0.96, EW=464 g/eq; 2155 meq.) and 43.0 g of 2-chloro-5-(trifluoromethyl)pyridine of formula Cl(C.sub.5H.sub.3N)CF.sub.3 (237 meq.) were charged into a 5 l round-bottomed flask equipped with mechanical stirrer, dropping funnel, thermometer and condenser. The resulting non-homogeneous mixture was placed under dry nitrogen and heated at 60° C. under stirring. In a separated flask, 25.4 g of potassium tert-butoxide (95%, 215 meq) was dissolved in 260 g of tert-butyl alcohol (TBA); the resulting clear solution was transferred via a double-ended needle into the dropping funnel and slowly added to the mixture of PFPE-Pol and 2-chloro-5-(trifluoromethyl)pyridine under stirring at 65° C. for 4.5 hours; after this time, precipitation of KCl was observed. After further 60 minutes under stirring at 65° C., a 10% conversion was achieved, as confirmed by .sup.19F-NMR spectroscopy. After cooling, the mixture was washed four times with 4000 g distilled water and 20 g HCl 37% w/w water solution. Every time the resulting two phases were vigorously stirred at room temperature for a few minutes and, after separation, the lower organic layer was collected. The solvents (TBA and traces of water) were removed by distillation at 70° C. under reduced pressure (residual pressure=2 Pa) to afford 1016 g crude product with a hydroxyl equivalent weight EW=478.5 g/eq and having formula: X*—OCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O).sub.a1(CF.sub.2O).sub.a2CF.sub.2CH.sub.2O—X wherein X*═H (90% on molar basis) or X*═(C.sub.5H.sub.3N)CF.sub.3 (10% on molar basis).

Step (b)—Preparation of a Mixture (M-2) from Mixture (M-1) and Hexachlorocyclophosphazene

[0197] 1000.0 g of mixture (M-1) (EW=478.5 g/eq; 2090 meq.) obtained from step (a) were charged into a 5 l round-bottomed flask equipped with mechanical stirrer, dropping funnel, thermometer and condenser, and then added with 73 g KOH (554 meq.; 42.5% solution in water). The mixture was heated and maintained at 70° C. under stirring, then vacuum was applied to the flask by means of a mechanical pump until complete elimination of water (about 60 minutes at P=3 kPa), to obtain a homogeneous solution. In a separated flask, 14.6 g hexachlorocyclotriphosphazene (HCP, 252 meq.) was dissolved in 500 g 1,3-hexafluoroxylene (HFX); the resulting solution was transferred via a double-ended needle into the dropping funnel and slowly added to the solution of (M-1) and KOH, under stirring at 78° C., for 6.5 hours. The reaction mixture was maintained at 78° C. under stirring, monitoring the conversion from time to time by .sup.31P-NMR analysis. After 60 minutes, conversion was quantitative (singlet in the .sup.31P-NMR spectrum at 17 ppm) and the reaction was stopped. After cooling to room temperature, the mixture was added with 510 g distilled water, 45 g HCl 37% w/w water solution and 34 g isobutyl alcohol. The two phases were vigorously stirred and, after separation, the lower organic layer was collected. The procedure was repeated, using 425 g of distilled water instead of 510. After separation, the solvents (HFX and isobutyl alcohol) were removed by distillation at 70° C. under reduced pressure (P=2 Pa) to afford 958 g crude product which was submitted to thin-layer distillation so as to remove most of the excess of unreacted mixture (M-1). Through two passages at 120° C. (P=2 Pa) and 140° C. (P=0.6 Pa) two fractions (75% and 7% by weight, respectively) of only unreacted mixture (M-1), as confirmed by the absence of signals in the .sup.31P-NMR spectrum, were removed, leaving 170 g of a high boiling, low volatility residue, which was characterized by .sup.19F-NMR, .sup.1H-NMR and .sup.31P-NMR. The GPC chromatogram showed four main components having a peak molecular weight of 1280, 4550, 7550 and 10100 dalton respectively. The first component corresponds to residual unreacted mixture (M-1), the second component is attributed to the resulting compound (L-2) and the corresponding spiro (L-2) and ansa (L-2) compounds, while the last two components are most likely attributed to bridged by-products.

Step (c)—Fractionation of Mixture (M-2) with Supercritical Carbon Dioxide (scCO.sub.2)

[0198] Mixture (M-2) obtained from step (b) was charged into a 300 ml SFT-150 Supercritical CO.sub.2 Extraction System and heated at 100° C. Through a step-by-step pressure increase (from 19 to 50 MPa) and operating at a CO 2 flow rate of 4 NI/min, compound (L-2) and the corresponding spiro (L-2) and ansa (L-2) were isolated. Any residual unreacted mixture (M-1) was easily removed at scCO.sub.2 low pressure, while bridged by-products were selectively collected at high pressure. Each fraction was characterized by .sup.31P-NMR, .sup.19F-NMR, .sup.1H-NMR, .sup.13C-NMR and GPC. Fractions containing only compound (L-2) and the corresponding spiro (L-2) and ansa (L-2) were pooled together (34.6% by weight). The ratio R between the P—OCH.sub.2CF.sub.2O— and the —OCF.sub.2X end-groups (X═—CH.sub.2OH, —CH.sub.2O(C.sub.5H.sub.3N)CF.sub.3, —F or —H, measured by .sup.19F-NMR, .sup.1H-NMR and .sup.13C-NMR) was found to be 1.25, corresponding to a molar percent composition of 41% (L-2) and 59% spiro (L-2)+ansa (L-2). The molar ratio between —CH.sub.2OH and —CH.sub.2O(C.sub.5H.sub.3N)CF.sub.3 end-groups resulted to be 8.27, corresponding to 0.51 —CH.sub.2O(C.sub.5H.sub.3N)CF.sub.3 end-groups per molecule.

Example 2

[0199] Step (a)—Preparation of a Mixture (M-1) [Reaction of a PFPE-Pol with 2-chloro-2,4-dinitrobenzene] (target conversion=31%)

[0200] 600.0 g of PFPE-Pol of formula: HO—CH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O).sub.a1(CF.sub.2O).sub.a2CF.sub.2CH.sub.2—OH

[0201] (MW=1027 g/mol, a1/a2=0.95, EW=515 g/eq; 1165.0 meq.), 73.4 g of 2-chloro-2,4-dinitrobenzene of formula ClC.sub.6H.sub.3(NO.sub.2).sub.2 (362.4 meq.), 112.5 g of potassium carbonate (814 mmol), 4.98 g of tetramethylammonium hydroxide solution (25 wt. % in H.sub.2O, 13.7 mmol) and 300.0 g of acetonitrile were charged into a 2 l three-necked round-bottomed flask equipped with magnetic stirrer, thermometer and condenser. The resulting non-homogeneous mixture was placed under dry nitrogen and heated at 70° C. under stirring. After 7 hours of reaction under stirring at an internal temperature of 70° C., the conversion was 28.7%, as confirmed by .sup.19F-NMR spectroscopy. The reaction was stopped and the mixture was cooled down to room temperature. The mixture was washed first with distilled water (1200 g) and then three times with 1000 g distilled water and 20 g isobutanol. Every time the resulting two phases were vigorously stirred at room temperature for a few minutes and, after separation, the lower organic layer was collected. The solvents (isobutanol, acetonitrile and traces of water) were removed by distillation at 60° C. under reduced pressure (residual pressure=2 Pa) to afford 649 g crude product with a hydroxyl equivalent weight EW=769 g/eq and having formula: X*—OCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O).sub.a1(CF.sub.2O).sub.a2CF.sub.2CH.sub.2O—X* where X*═H (71.3% on molar basis) or X*═(C.sub.6H.sub.3)(NO.sub.2).sub.2(28.7% on molar basis).

Step (b)—Preparation of a Mixture (M-2) from Mixture (M-1) and Hexachlorocyclophosphazene

[0202] 647.7 g of mixture (M1) (EW=769 g/eq; 842 meq.) obtained from step (a) were charged into a 2 l three-necked round-bottomed flask equipped with magnetic stirrer, dropping funnel, thermometer and condenser, and then added with 29.4 g KOH (222.7 meq.; 42.5% solution in water). The mixture was heated to 80° C. and kept at this temperature under stirring, while vacuum was applied to the flask by means of a mechanical pump until complete elimination of water (about 40 minutes at P=2 Pa), to obtain a homogeneous solution. In a separated flask 5.9 g hexachlorocyclotriphosphazene (HCP, 102 meq.) was dissolved in 184 g 1,3-hexafluoroxylene (HFX). The resulting solution was transferred via a double-ended needle into the dropping funnel and slowly added to the solution of (M1) and KOH, under stirring at 77-78° C. during 4 hours. The reaction mixture was kept at this temperature under stirring, monitoring the conversion from time to time by .sup.31P-NMR analysis. After 3 hours, the conversion was quantitative (singlet in the .sup.31P-NMR spectrum at 17 ppm) and the reaction was stopped. After cooling at room temperature, the mixture was added with 143 g distilled water, 22 g HCl 37% w/w water solution and 21 g isobutyl alcohol. The two phases were vigorously stirred and, after separation, the lower organic layer was collected. A second washing was carried out with 500 g distilled water and 20 g isobutyl alcohol. After phase separation, the solvents (HFX and isobutyl alcohol) were removed by distillation at 80° C. under reduced pressure (P=2 Pa), to afford 636 g crude product which was submitted to thin-layer distillation. Through two passages at 160° C. (P=0.8 Pa) and 190° C. (P=0.8 Pa), two fractions of only unreacted mixture (M-1), as confirmed by the absence of signals in the .sup.31P-NMR spectrum, were removed, leaving 161 g of a high boiling, low volatility residue, which was characterized by .sup.19F-NMR, .sup.1H-NMR and .sup.31P-NMR. The residue was submitted to a further distillation step at 250° C. and P=0.8 Pa in order to quantitatively remove the unreacted mixture (M-1) as confirmed by GPC.

Step (c)—Fractionation of Mixture (M-2) with Supercritical Carbon Dioxide (scCO.sub.2)

[0203] Mixture (M-2) obtained from step (b) was charged into a 300 ml SFT-150 Supercritical CO.sub.2 Extraction System and heated at 100° C. Through a step-by-step pressure increase (from 18 to 40 MPa) and operating at a CO 2 flow rate of 4 NI/min, 19 fractions were collected. Compound (L-2) and the corresponding spiro (L-2) and ansa (L-2) compounds were separated from the bridged by-products, which were selectively collected at high pressure. Each fraction was characterized by .sup.31P-NMR, .sup.19F-NMR, .sup.1H-NMR, .sup.13C-NMR and GPC. Fractions 10 to 12 (16.53 g) were pooled together and the ratio R between the P—OCH.sub.2CF.sub.2O— and the —OCF.sub.2X end-groups (X═—CH.sub.2OH, —CH.sub.2O(C.sub.6H.sub.3)(NO.sub.2).sub.2, —F or —H) measured by .sup.19F-NMR and .sup.1H-NMR. R was found to be 1.14, corresponding to a molar percent composition of 63% (L-2) and 37% spiro (L-2)+ansa (L-2). The molar ratio between —CH.sub.2OH and —CH.sub.2O(C.sub.6H.sub.3)(NO.sub.2).sub.2 end-groups resulted to be 2.95.