U.S. patent application number 11/588325 was filed with the patent office on 2007-05-10 for hydrofluoroethers having at least one hydrogenated -ocfx'ch3 end group wherein x'=f, cf3 and their preparation process.
This patent application is currently assigned to SOLVAY SOLEXIS S.p.A.. Invention is credited to Antonella Di Meo, Rosaldo Picozzi, Claudio Tonelli.
Application Number | 20070106092 11/588325 |
Document ID | / |
Family ID | 30130959 |
Filed Date | 2007-05-10 |
United States Patent
Application |
20070106092 |
Kind Code |
A1 |
Picozzi; Rosaldo ; et
al. |
May 10, 2007 |
Hydrofluoroethers having at least one hydrogenated -OCFX'CH3 end
group wherein X'=F, CF3 and their preparation process
Abstract
Hydrofluoroethers of formula: T-CFX'--O--R.sub.f--CFX-T' (II)
wherein: T=CH.sub.3; X, X', equal to or different from each other,
are selected between F, CF.sub.3; T'=F, Cl, H, C.sub.1--C.sub.3
perfluoroalkyl, CH.sub.3, CH.sub.20H, COC.sub.1, CHO, CO.sub.2H;
R.sub.f is a perfluoroalkylene or a perfluoropolyoxyalkylene and
respective preparation process by reduction with hydrogen in the
presence of a platinum catalyst supported on metal fluorides of the
corresponding compounds with at least one --COCl end group.
Inventors: |
Picozzi; Rosaldo; (Milano,
IT) ; Di Meo; Antonella; (Milano, IT) ;
Tonelli; Claudio; (Milano, IT) |
Correspondence
Address: |
ARENT FOX PLLC
1050 CONNECTICUT AVENUE, N.W.
SUITE 400
WASHINGTON
DC
20036
US
|
Assignee: |
SOLVAY SOLEXIS S.p.A.
|
Family ID: |
30130959 |
Appl. No.: |
11/588325 |
Filed: |
October 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10630697 |
Jul 31, 2003 |
7161030 |
|
|
11588325 |
Oct 27, 2006 |
|
|
|
Current U.S.
Class: |
562/587 ;
562/840; 568/448; 568/677 |
Current CPC
Class: |
C08G 65/007 20130101;
C08G 65/226 20130101; C07C 59/135 20130101; C07C 43/315 20130101;
C07C 43/126 20130101; C07C 43/137 20130101; C08G 65/322
20130101 |
Class at
Publication: |
562/587 ;
562/840; 568/448; 568/677 |
International
Class: |
C07C 59/10 20060101
C07C059/10; C07C 47/02 20060101 C07C047/02; C07C 51/58 20060101
C07C051/58 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 1, 2002 |
IT |
MI2002 A 001731 |
Claims
1. Hydrofluoroethers of formula: T-CFX'--O--R.sub.f--CFX-T' (II)
wherein: T=CH.sub.3; X, X', equal to or different from each other,
are selected between F, CF.sub.3; T'=F, Cl, H, C.sub.1--C.sub.3
perfluoroalkyl, CH.sub.3, CH.sub.2OH, COCl, CHO, CO.sub.2H; R.sub.f
is selected from: C.sub.2--C.sub.15 perfluoroalkylene;
--(C.sub.2F.sub.4O).sub.m(CF.sub.2CF(CF.sub.3)O).sub.n(CF.sub.2O).sub.p(C-
F(CF.sub.3)O).sub.q-- wherein the sum n+m+p+q ranges from 2 to 200,
the (p+q)/(m+n+p+q) ratio is lower than or equal to 10:100, the n/m
ratio ranges from 0.2 to 6; m, n, p, q are equal to or different
from each other and when m, n range from 1 to 100, then p, q range
from 0 to 80; the units with n, m, p, q indexes being statistically
distributed along the chain; --(CF.sub.2CF.sub.2CF.sub.2O).sub.r--
wherein r ranges from 2 to 200, --(CF(CF.sub.3)CF.sub.2O).sub.s--
wherein s ranges from 2 to 200
2. Hydrofluoroethers according to claim 1, wherein R.sub.f is
selected from the following structures:
--(CF.sub.2CF.sub.2O).sub.m--(CF.sub.2O).sub.p--,
--(CF.sub.2CF(CF.sub.3)O).sub.n--(CF.sub.2O).sub.p--(CF(CF.sub.3)O).sub.q-
.
3-7. (canceled)
8. Hydrofluoroethers of claim 1, wherein the (p+q)/(m+n+p+q) ratio
is between 0.5:100 and 4:100.
9. Hydrofluoroethers of claim 1, wherein the n/m ratio ranges from
0.5 to 3.
10. Hydrofluoroethers of claim 1, wherein when m, n range from 1 to
80, then p, q range from 0 to 80.
11. Hydrofluoroethers of claim 10, wherein when m, n range from 1
to 80, then p, q range from 0 to 50.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a Divisional Application, which claims the benefit
of pending U.S. patent application Ser. No. 10/630,697, filed Jul.
3, 2003. The disclosure of the prior application is hereby
incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to hydrofluoroethers
characterized in having at least one hydrogenated --OCFX'CH.sub.3
end group wherein X'=F, CF.sub.3 and their preparation process.
[0003] More specifically, the preparation process relates to the
reduction with H.sub.2, in the presence of platinum catalysts (Pt),
of the corresponding fluorinated acylchloride precursors.
[0004] Hydrofluoroethers prepared by direct fluorination with
F.sub.2 or electrochemical fluorination of an ether compound or by
alkylation of fluorinated alcohols are known.
[0005] In patent application WO 99/47,480 it is shown that
hydrofluoroethers can be obtained by alkylation of fluorinated
carbonyl compounds. The above methods employ starting compounds
having a low molecular weight with a number of carbon atoms equal
to or lower than 12, besides they give low yields and selectivity,
and do not give hydrofluoroethers having at least one OCFX'CH.sub.3
end group with X'=F, CF.sub.3.
[0006] More specifically patent application WO 99/47,480 describes
an alkylation process of perfluorinated carbonyl compounds in the
presence of a Lewis acid, for example SbF.sub.5. Although in the
general formula: R.sub.f--(O--R).sub.x (I) wherein:
[0007] R.sub.f is a fluorinated C.sub.1--C.sub.15 alkyl, optionally
substituted and optionally containing heteroatoms in the chain as
N, O, S;
[0008] R is a C.sub.1--C.sub.10 alkyl, optionally substituted,
[0009] x ranges from 1 to 3,
[0010] a great number of potential hydrofluoroethers is contained,
really by the process only hydrofluoroethers having end groups
different from --OCFX'CH.sub.3 are obtainable. See the Examples of
patent application WO 99/47,480. Therefore the compounds having
--OCFX'CH.sub.3 termination have not been prepared and no
indication about how to prepare them is given. Accordingly the
skilled man in the art on the basis of the aforesaid patent and of
the common general knowledge is unable to prepare the compounds of
the present invention.
[0011] Generally the reaction described in patent application WO
99/47,480 proceeds with very low conversions when R.sub.f is
branched. The reaction shows the limitation that to obtain
acceptable conversions it is necessary to use CH.sub.3F as
alkylating agent, has the drawback to require the use of Lewis
acids which are aggressive and need the use of pressure resistant
equipments built in special substances. Furthermore HF forms,
producing further problems in the equipment choice. Since the
alkylation reaction is an equilibrium reaction, it does not allow
the obtainment of hydrofluoroethers with a high yield.
[0012] The Applicant has furthermore found that by using a Lewis
acid as SbF.sub.5, in the ratios suggested by patent application WO
99/47,480 and by following the same modalities suggested by the
same, no hydrofluoroethers are obtained starting from precursors
having a perfluoropolyether structure, in particular containing
--OCF.sub.2O-- sequences; besides the use of SbF.sub.5 amounts
higher than those suggested causes the almost total degradation of
the initial perfluoropolyether structure without obtaining however
hydrofluoroethers (see the comparative Examples).
[0013] The need was therefore felt to obtain hydrofluoroethers by a
process avoiding the prior art inconveniences and limitations.
[0014] It has been found a hydrogenation process of fluorinated
precursors containing acylchloride groups carried out in the
presence of platinum catalysts which allows to obtain
hydrofluoroethers characterized in having at least one
--OCFX'CH.sub.3 end group and quantitative conversions with
selectivity even of the order of 70%.
[0015] An object of the present invention are therefore
hydrofluoroethers of formula: T-CFX'--O--R.sub.f--CFX-T' (II)
wherein: [0016] T=CH.sub.3; [0017] X, X', equal to or different
from each other, are selected from F, CF.sub.3; [0018] T'=F, Cl, H,
C.sub.1--C.sub.3 perfluoroalkyl, CH.sub.3, CH.sub.2OH, COCl, CHO,
CO.sub.2H; [0019] R.sub.f is selected from:
[0020] C.sub.2--C.sub.15 perfluoroalkylene;
[0021]
--(C.sub.2F.sub.4O).sub.m(CF.sub.2CF(CF.sub.3)O).sub.n(CF.sub.2O).-
sub.p(CF(CF.sub.3)O).sub.q--
[0022] wherein:
[0023] the sum n+m+p+q ranges from 2 to 200, the (p+q)/(m+n+p+q)
ratio is lower than or
[0024] equal to 10:100, preferably comprised between 0.5:100 and
4:100, the n/m ratio ranges
[0025] from 0.2 to 6, preferably from 0.5 to 3; m, n, p, q are
equal to or different from each other
[0026] and when m, n range from 1 to 100, preferably from 1 to 80,
then p, q range from 0 to 80,
[0027] preferably from 0 to 50; the units with n, m, p, q indexes
being statistically distributed
[0028] along the chain; [0029] --(CF.sub.2CF.sub.2CF.sub.2 O)
.sub.r-- wherein r ranges from 2 to 200, [0030] --(CF (CF.sub.3)
CF.sub.2 O) .sub.s-- wherein s ranges from 2 to 200,
[0031] The preferred structures of the perfluorooxyalkylene chain
R.sub.f are selected from the following: [0032] --(CF.sub.2CF.sub.2
O).sub.m-- (CF.sub.2 O) .sub.p--, [0033] --(CF.sub.2CF (CF.sub.3)
O).sub.n-- (CF.sub.2 O) .sub.p--(CF (CF.sub.3) O) .sub.q [0034]
wherein the indexes have the above meanings.
[0035] A further object of the present invention is the preparation
process of the formula (II) compounds comprising the reduction of
the formula (III) corresponding precursors:
T''-CFX'--O--R.sub.f--CFX-T''' (III) wherein: [0036] T'' is --COCl,
[0037] T'''=F, C.sub.1--C.sub.3 perfluoroalkyl, COCl, H, Cl, [0038]
X, X', R.sub.f are as defined in formula (II), carried out with
gaseous hydrogen in the presence of a catalyst formed by supported
platinum, preferably on metal fluorides, preferably in the presence
of inert solvents, at a temperature in the range 20.degree.
C.-150.degree. C., preferably 80.degree. C.-120.degree. C., at a
pressure between 1 and 50 atm, preferably between 1 and 10 atm.
[0039] The formula (III) compounds having at least one --COCl end
group are known, preparable for example by reaction of the
corresponding PFPEs having --COF or --COOH end groups with
inorganic chlorides or chlorinating agents such as thionyl
chloride; preferably they are prepared according to what described
in Italian patent applications MI2002A 001733 and MI2002A 001734
filed at the same time as the present application, and herein
incorporated by reference, by a solid-liquid reaction between a
large excess of inorganic chloride, CaCl.sub.2 and a PFPE
acylfluoride, at a temperature higher than 100.degree. C., under
strong stirring or alternatively a PFPE acylfluoride can be
hydrolyzed obtaining the corresponding carboxylic acid which is
subsequently treated with SOCl.sub.2, in the presence of a tertiary
amine, at a temperature in the range 50-100.degree. C., obtaining
the corresponding acylchloride.
[0040] The formula (II) hydrofluoroethers can alternatively be
obtained from the corresponding PFPEs having at least one --CHO or
--CH(OH)O(CH.sub.2).sub.tR end group wherein t=0 or 1 and R is a
C.sub.1--C.sub.10 alkyl group, H, or R.sub.f.
[0041] The process can be carried out in a continuous or
discontinuous way.
[0042] The metal fluorides are preferably selected from the group
formed by CaF.sub.2, BaF.sub.2, MgF.sub.2, AlF.sub.3; more
preferably CaF.sub.2. The Pt concentration on the support is
comprised between 0.1% and 10% with respect to the total weight of
the catalyst, preferably between 1% and 2% by weight. The used
catalyst amount is in the range 1%-100% by weight with respect to
the weight of the formula (III) compound, preferably 10%-100% by
weight.
[0043] The inert solvents can for example be linear or cyclic
perfluorinated ethers such for example perfluorotetrahydrofuran,
perfluorotetrahydropyran, or their mixtures.
[0044] The invention hydrofluoroethers having at least one
--OCFX'CH.sub.3 end group with X'=F, CF.sub.3 can be used as
refrigerants, solvents in cleaning processes of printed circuits,
and degreasing in vapour phase of metal components as substituents
of CFCs, HCFCs and PFCs, resulted harmful for the ozone layer or
show a high GWP (greenhouse potential).
[0045] Besides they found application for the wide range of
utilization temperatures as substituents of HFCs which in some
cases have a limited application as refrigerants due to their very
low boiling temperature or their very high freezing point.
[0046] The following Examples are given for illustrative and not
limitative purposes of the present invention.
EXAMPLES
Example 1
[0047] In a 1,000 ml flask, equipped with mechanical stirrer,
bubbling pipe to introduce hydrogen/nitrogen, condenser with a
bubble-counter
36.7 g of Pt supported on CaF.sub.2 (Pt=1.5% by weight), 400 ml of
mixture 1:1 of perfluorobutyltetrahydrofuran and
perfluoropropyltetrahydropyran (D100), are introduced.
[0048] By external heating with thermostated oil bath, the solvent
is brought to the boiling temperature (100.degree. C.), then
hydrogen is fed at atmospheric pressure at a flow-rate of 20 1/h,
and 36.7 g of perfluoropolyether (PFPE) acylchloride of formula
(IV) CF.sub.3O(CF.sub.2CF (CF.sub.3) O) .sub.n (CF.sub.2O)
.sub.pCF.sub.2COCl (IV) wherein n/p=25 and n, p are integers such
that the number average molecular weight is 400, are fed by
dropping funnel in 30 minutes.
[0049] When the PFPE-COCl feeding is over, the reduction is let
complete for 15 minutes in hydrogen flow. It is then cooled to room
temperature in nitrogen flow. The raw reaction compound is filtered
to recover the catalyst.
[0050] The NMR (.sup.19F and .sup.1H) analysis of the compound
shows a 100% conversion of the starting PFPE-acylchloride and a
yield in formula (V) hydrofluoroether of 60% by moles:
CF.sub.3O(CF.sub.2CF (CF.sub.3) O).sub.n (CF.sub.2O)
.sub.pCF.sub.2CH.sub.3 (V)
[0051] The NMR analysis shows furthermore the presence of the
alcoholic compound of structure (VI) in an amount equal to 40% by
moles: CF.sub.3O(CF.sub.2CF (CF3) O).sub.n (CF.sub.2O)
.sub.pCF.sub.2CH.sub.2OH (VI)
[0052] To separate the hydrofluoroether (V) from the alcohol (VI),
the raw reaction compound is chromatographed on silica gel using D
100 as eluent. From the extract, after solvent distillation, 18 g
of a compound are obtained which by the NMR (.sup.19F and .sup.1H)
analysis shows to be the hydrofluoroether of formula (V).
Example 2
[0053] In the same equipment of the Example 1
32.5 g of Pt supported on CaF.sub.2 (Pt=1.5%), 150 ml of D100, are
introduced.
[0054] One operates as described in the Example 1, by feeding 38.9
g of PFPE acylchloride of formula (VII): Cl (CF.sub.2CF (CF.sub.3)
O) .sub.nCF.sub.2COCl (VII) wherein n=3 and the number average
molecular weight equal to 647.
[0055] The NMR (.sup.19F and .sup.1H) analysis of the compound
shows a 100% conversion of the starting PFPE-acylchloride, and a
yield of 70% by moles in hydrofluoroether of formula (VIII): Cl
(CF.sub.2CF (CF.sub.3) O) .sub.nCF.sub.2CH.sub.3 (VIII)
[0056] The NMR analysis shows furthermore the presence of the
alcohol compound in an amount equal to 30% by moles, having
structure (IX): Cl (CF.sub.2CF (CF.sub.3) O)
.sub.nCF.sub.2CH.sub.2OH (IX)
[0057] To separate the hydrofluoroether from the alcohol, the raw
reaction compound is chromatographed on silica gel using D 100 as
eluent. From the extract, after solvent distillation, 23 g of a
compound are obtained which by the NMR. (.sup.19F and .sup.1H)
analysis shows to be the hydroflucroether of formula (VIII).
[0058] The experimentation is repeated with the same modalities
feeding each time 38 g of the acylchloride of the Example 2 by
using the same catalyst of the preceding test. After a cycle of 10
consecutive tests no variation of the reaction conversion and
selectivity has been obtained and therefore no catalyst
deactivation was evident.
Example 3
[0059] In a 100 ml flask equipped with mechanical stirrer, bubbling
pipe to introduce hydrogen/nitrogen, condenser with
bubble-counter,
1 g of Pt supported on C (Pt=5%),
40 ml of D100, are introduced.
[0060] One operates as described in the Example 1, by feeding 3.54
g of PFPE-acylchloride of the Example 2.
[0061] The NMR (.sup.19F and .sup.1H) analysis of the compound
shows a partial conversion of the starting PFPE-acylchloride (53%
by moles) and the converted compound shows to be a mixture of
compounds of which the formula (VIII) hydrofluoroether forms the
64% by moles.
[0062] The difference to 100 is constituted by the acid of formula
(X): Cl (CF.sub.2CF (CF.sub.3) O) .sub.nCF.sub.2CO.sub.2H (X)
Example 4
[0063] In the same equipment of the Example 1
30.4 g of Pt on CaF.sub.2 (Pt=1.5%),
150 ml of D100, are introduced.
[0064] One operates as described in the Example 1, by feeding 35.2
g of PFPE-acylchloride of formula (XI): ClOCCF.sub.2O
(CF.sub.2CF.sub.2O) .sub.m (CF.sub.2O) .sub.pCF.sub.2COCl (XI)
wherein m/p=1 and m, p are such that the number average molecular
weight is 2,030.
[0065] The NMR (.sup.19F and .sup.1H) analysis of the compound
shows a 100% conversion of the starting PFPE-acylchloride obtaining
a reaction mixture which on an average has 60% by moles of
--CF.sub.2CH.sub.3 end groups, 32% of --CF.sub.2CH.sub.2OH end
groups, 8% of CF.sub.2CO.sub.2H end groups.
[0066] From the mixture, after chromatography on silica and solvent
distillation, 5.8 g of hydrofluoroether of formula:
CH.sub.3CF.sub.2 O(CF.sub.2CF.sub.2O) .sub.n (CF.sub.2O)
.sub.mCF.sub.2CH.sub.3 (XII), 12 g of PFPE of formula:
CH.sub.3CF.sub.2O (CF.sub.2CF.sub.2O) .sub.m (CF.sub.2O)
.sub.mCF.sub.2CH.sub.2OH (XIII), 9.7 g of PFPE-alcohol of formula:
HOCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O) .sub.m (CF.sub.2O)
.sub.pCF.sub.2CH.sub.2OH (XIV), and 2.4 g of PFPE-acid of formula
(XV): HO (O) CCF.sub.2O(CF.sub.2CF.sub.2O) .sub.m (CF.sub.2O)
.sub.pCF.sub.2C (O) OH (XV), are obtained.
Example 5
[0067] In the same equipment of the Example 3
3.26 g of Pt on CaF.sub.2 (Pt=1.5%),
40 ml of D100, are introduced.
[0068] One operates as described in the Example 1, by feeding 3.21
g of PFPE-aldehyde of formula (XVI): H (O) CCF.sub.2O
(CF.sub.2CF.sub.2O) .sub.m (CF.sub.2O) .sub.pCF.sub.2C (O) H (XVI)
wherein m/p=1 and m, p are such that the number average molecular
weight is 2,000.
[0069] The NMR (.sup.19F and .sup.1H) analysis of the compound
shows a 100% conversion of the starting PFPE-aldehyde with the
obtainment of a reaction mixture which on an average has 30% by
moles of --CF.sub.2CH.sub.3 end groups and 70% of
--CF.sub.2CH.sub.2OH groups.
Example 6
[0070] In the same equipment of the Example 3
2.9 g of Pt on CaF.sub.2 (Pt=1.5%),
40 ml of D100, are introduced.
[0071] One operates as described in the Example 1, by feeding 2.48
g of hydrated PFPE-aldehyde of formula: (HO) .sub.2HCCF.sub.2O
(CF.sub.2CF.sub.2O) .sub.m (CF.sub.2O) .sub.pCF.sub.2CH (OH) .sub.2
(XVII) wherein m/p=1 and m, p are such that the number average
molecular weight is 2,000.
[0072] The NMR (.sup.19F and .sup.1H) analysis of the compound
shows a 100% conversion of the starting hydrated PFPE-aldehyde with
the obtainment of a reaction mixture which on an average has 14% by
moles of --CF.sub.2CH.sub.3 end groups and 86% of
--CF.sub.2CH.sub.2OH groups.
Example 7 (Comparative)
[0073] In the same equipment of the Example 3
4 g of Pt on CaF.sub.2 (Pt=1.5%),
40 ml of D100, are introduced.
[0074] By operating as described in the Example 1, 4 g of
PFPE-alcohol of formula: Cl (CF.sub.2CF (CF.sub.3) O)
.sub.nCF.sub.2CH.sub.2OH (IX) are fed, wherein n=3 and number
average molecular weight equal to 604.
[0075] The compound NMR (.sup.19F and .sup.1H) shows that no
reaction has taken place, only the PFPE alcohol of formula (IX)
being present.
Example 8 (Comparative)
[0076] In the same equipment of the Example 3
4 g of Pt on CaF.sub.2 (Pt=1.5%),
40 ml of D100, are introduced.
[0077] By operating as described in the Example 1, 4 g of
PFPE-alcohol of formula: HOCH.sub.2CF.sub.2O (CF.sub.2CF.sub.2O)
.sub.m (CF.sub.2O) .sub.pCF.sub.2CH.sub.2OH (XIV) are introduced,
wherein m/p=1 and m, p are such that the number average molecular
weight is 2,000.
[0078] The NMR (.sup.19F and .sup.1H) of the compound shows that no
reaction has taken place; only the PFPE-alcohol of formula (XIV)
being present.
Example 9 (Comparative)
[0079] In the same equipment of Example 3
60 mg of Pt black,
40 ml of D100, are introduced.
[0080] By operating as described in the Example 1, 4 g of
PFPE-acylchloride of formula (VII) of the Example 2, are
introduced.
[0081] The NMR (.sup.19F and .sup.1H) of the compound shows that no
reaction has taken place, only the PFPE-acylchloride of formula
(VII) being present.
Example 10 (Comparative)
[0082] A 250 ml AISI 316 reactor equipped with magnetic stirring,
bubbling pipe, thermocouple for the temperature reading and
manometer, is dried at 70.degree. C. under vacuum for 7 hours. It
is then transferred in dry-box and fed with:
47 mg of SbF.sub.5,
10 g of PFPE-acylfluoride of formula: FC (O) CF.sub.2O
(CF.sub.2CF.sub.2O) .sub.m (CF.sub.2O) .sub.pCF.sub.2C (O) F
(XVIII) wherein m/p=2.13 and m, p such that the number average
molecular weight is 1,529.
[0083] The reactor is reassembled in the dry-box and cooled to
-8.degree. C. After the reactor has been put under vacuum, 1.82 g
of gaseous CH.sub.3CF.sub.3 are fed. Then one operates by letting
the reaction mixture reach the room temperature, then heating it to
30.degree. C. and leaving it for 45 minutes at said temperature.
The reactor is then cooled again to -30.degree. C. and after 20
minutes the reaction mixture is quenched by the addition of 8 g of
anhydrous methanol. It is brought to room temperature, then the
reaction raw compound is discharged from the reactor. The methanol
excess is removed by distillation at reduced pressure. 8.9 g of a
compound are obtained, which at the .sup.19F and .sup.1H NMR
analysis shows to be only a PFPE-ester of formula: CH.sub.3C (O)
CF.sub.2O (CF.sub.2CF.sub.2O).sub.m (CF.sub.2O) .sub.pCF.sub.2C (O)
OCH.sub.3 (XIX) i.e. the reaction compound between the starting
PFPE-acylfluoride and the methyl alcohol.
[0084] Therefore no formation of hydrofluoroether has been
noticed.
Example 11 (Comparative)
[0085] In the same equipment of the Example 10 and proceeding as
described in the Example 10, the acid catalyst amount is increased
by feeding:
2.2 g of SbF.sub.5,
10.5 g of PFPE-acylfluoride of the Example 10.
[0086] It is cooled to -80.degree. C. noticing a residual pressure
of 1.5 bar. One proceeds however as described in the Example 10 by
feeding 1.82 g of CH.sub.3CF.sub.3. A further pressure increase is
observed. After quenching with methanol at low temperature, it is
let reach again the room temperature. The gas is sampled and is
analyzed by gas-mass. It shows to be constituted by a mixture of
decomposition compounds of the PFPE-acylfluoride chain, having low
number average molecular weight (MW.ltoreq.500).
[0087] None of these shows hydrofluoroether structure with
--OCF.sub.2CH.sub.3 end groups.
[0088] The liquid reaction mass gives only 2.5 g of PFPE-ester of
formula: CH.sub.3C (O) CF.sub.2O (CF.sub.2CF.sub.2O) .sub.m
(CF.sub.2O) .sub.pCF.sub.2C (O) OCH.sub.3 (XIX) wherein m/p=5 and
m, p are such that the number average molecular weight is
1,371.
* * * * *