DE1770126C3 - Perfluorinated polyethers and mixed polyethers and processes for their preparation - Google Patents

Description

ζ. B. --COF, -CF ₂ -CO-CF ₁ . -CF ₂ H and CFH-CF ₃ , as a result of which these products are chemically activated or their thermal stability is limited.

It has now been found that it is possible to use these products or the mixtures of these Convert products into products or mixtures of products that have essentially the same structure have, in whose molecules, however, the peroxide oxygen is completely absent and the terminal groups the chains consisted only of perfluoroalkyl groups; therefore these products possess exceptional Features related to chemical and thermal stability.

The products according to the invention are compounds or their mixtures with the structure of perfluorinated Polyethers of homopolymeric or copolymeric nature of the general formula

at the —C3F6 “and —C2F4“ perfluoroalkylene groups the structure

-CF ₂ -CF- or -CF ₂ -CF ₂ -

and the three different perfluoroalkylene units are randomly distributed along the chain, P. Q and R are mean indices of the composition and only P and / or R can be zero, the sum P + Q + R has a value between 2 and 200, the Ratio of the index P / Q + /? has a value of 0-50, the ratio R / Qcinen Wen has 0-10, X and V terminal residues of the chain, such as

-CF ₃ . -C ₂ F ₅ , -C ₃ F ₇ or -CF - O-CF,

CF,

with the restriction that the two end groups are -CF ₃ when both indices P and R are equal to zero, are the same or different from one another and are -CF ₃ or -C ₂ F- when only the index P is zero, and finally, if P is different from zero, the two end groups can be identical or different from one another and -CF ₃ , -C ₂ Fs or -C ₁ F; can mean, or one of them

CF ₃ -O-CF-

CF,
can represent.

When both subscripts P and R are zero, the polyethers have the formula

CFi-O-

and can be referred to as polyoxyprofluoromethylene.

Preferred polyethers are mixtures of perfluorinated polyethers with a mixed polyether structure in which the indices P, Q and <? do not necessarily have a value equal to that of whole numbers since they represent mean values.

The mixed polyethers and their mixtures, in which only the index is PNuII, are represented by the formula

XO- (CF ₂ -OJy- (C ₂ F ₄ -O) KY
characterized in which X and Y CFi or C> I-, the ratio between the number of —C ₂ F ₄ O units and that of —CFiO units which can be present simultaneously in a molecule of mixed polyethers of this type fluctuates generally between 0.01 and 10, preferably between 0.2 and 5.

If only the index R is zero. the mixed polyethers and their mixtures contain only -CF ₂ O units together with the -CjFoO units. Its mean structure is given by the formula

XO- (C ₃ FeO) P- (CF ₂ OJy-Y

expressed in which X and Y can be the same or different and have perfluoroalkyl groups of 1-3 Represent carbon atoms; one can too

CF ₃ -O — CF-

represent.

In general, the preferred average 2s ratio of the indexes Q / P is in the range of 1-0.02.

Mixed polyethers of the last two structures mentioned.

i.e. those containing Ci- and CY units and Cj- and Containing Ci units, and their mixtures are a preferred embodiment or a preferred The subject of the invention as a result of a favorable combination of properties that these products differentiate.

Connections of this nature are through one

characterized by very high chemical and thermal stability; also causes the presence of a

- CF ^ -O unit, e.g. B. with regard to the homopolyethers of hexafluoropropylene, an increase in the ratio between the number of —C — O bonds in the chain with respect to the —CC bonds: known-Hch, this means a lower rigidity of the molecular structure, thereby advantageously holding compounds e ^r having a lower viscosity, the molecular weight remains the same, and also a lower volatility

4s, with the viscosity remaining the same Another advantage is that the viscosity fluctuates less with temperature and in one lower pour point of the products mentioned. It is well known that while the —C —C bonds

so gen have a considerable energy threshold that opposes their rotation, this is not the case for -C-O bonds applies, so that a larger ratio of bonds - C - () - / - C - C- in the main chain the causes mentioned effects.

ss A very similar effect can also be achieved with mixed polyethers based on -C ₂ F ₄ O- unc

- CFjO units with respect to homopolyethers, which consist only of -C ₂ F ₄ O units, can be observed.

As stated above, the fluctuation is dei Viscosity with the temperature of the mixed polyethers and their mixtures, which have a fairly narrow distribution Molecular weights are very low, which means that the above-mentioned mixed polyethers are very high

'' s viscosity index. This property is be are known to be highly desirable when liquids are used in systems in which strong temperature fluctuations occur.

Furthermore, the advantageous effect on the properties of the perfluorinated polyethers through the presence of - CFiO units in their chain is demonstrated by the fact that the mixed polyethers, the repeating --C2F4O and --CFjO units in a ratio of 1: 5 to 5: 1 included, even at very low temperatures are fiussig, even at temperatures as low as - not crystallize 100 ⁰ C and - more importantly - at very low temperatures show no glass transition, while Homopolyäther with a (CJF ₄ O) "- structure and a relatively high molecular weight, for example those where η is greater than 100 but are crystalline products with a melting point of about 40 ^r C. Obviously, these crystalline products are unsuitable for use in the field of inert liquids because they are insoluble at room temperature. Finally, the presence of —CFjO units in the mixed polyether chain causes a notable improvement in the resistance to oxidation of these products Obviously, these three properties of perfluorinated polyethers with -CF ₂ O units, i.e. a very high viscosity index, a very low pour point and a very high resistance to oxidizing agents, are enhanced if the percentage mentioned - CF ₂ O units in the PoK ether chain increases, and they reach their highest value when the polyetherities consist only of repeating CFiO units.

However, there are other advantageous properties, such as high resistance to solvents. Hydrolyzing agents and chemicals, generally the polyether chain, have been found to be imparted by the presence of a fairly high fluorine resilience in the chain, ie when there is a substantial content of —CjFeO and / or -C ₂ F ₁ ) O units in the chain that the compounds with the most favorable combination of properties are those which simultaneously _{contain in the chain - (T ^ O units and -C) F 6} O and / or -C ₂ F ₄ O units.

The synthesis process of polyethers and mixed polyethers and their mixtures according to the invention is characterized in that one fluorine in pure or in a diluted form with polyethers and mixed polyesters and their mixtures. These starting materials have a chain structure. those of the compounds so obtained according to the invention in is essentially analogous, but they contain terminal groups of at least partially different Structure and optionally oxygen atoms linked in peroxide form. ss

The invention therefore also relates to a process for the production of perfluorinated polyethers and Mixed polyethers without a content of peroxide oxygen and their mixtures of the general formula

(in

XO (C ₁ I ',, O) ,. (CF ₂ O » _tf (C ₂ F ₄ O) _K Y

in which XY P, Q and R have the abovementioned words, which is characterized in that pure f, _s or fluorine diluted with an inert gas up to a fluorine sound of 10 vol. ^-1 Vu under pressures in the range VfMi O? to IO at and at temperatures of H) O to 350 ⁰ C with polyethers and mixed polyethers or their mixtures of the general average formula

WO - (- CjF ₍ , -O-) _s - (- CF ₂ -O-) _T - (- C _I F ₄ -O), q

converts, in the W and Z represent terminal radicals, where one

-CF ₃ , -CF ₃ -O-CF-. -COF.

CF ₃
—CF, -COF, —CF-COF,

-CF ₂ -CO-CF ₃ , -CF ₂ -C (OH) ₂ -CF ₃ .
-CF ₂ H and -CFH

CF ₃

represents when the subscript 5 is different from zero, while when S is equal to zero, it represents only -CF), -COF, -CF ₂ -COF and -CFjH, and the other terminal residue

-COl. -CF ₇ -COF,

CF-COF.

CF ₃

-CF ₂ -CO-CF ₃ , CF ₂ -C (OH) ₂ -CF ,.
-CF ₂ H and -CFH

CF ₃

represents when the index 5 is different from zero, while such other end group, when S is equal to zero, only -COF. -CF ₂ -COF and CF _{2 represents} H. (_0-) means an oxygen atom that is randomly distributed along the chain and is bound in peroxide form to the various oxyperfluoroalkylene units, S. T. U and V are mean indices of the composition, where 5, U and V can be zero, the sum S + T + has a value of 2-200, the ratio of the indices S / T + LJ ! '. Is between 0 and 50, the ratio U / T is between 0 and 10, the ratio V / S + T + U + \ is between 0 and 0 , 1 and the index V is zero when Sund U are zero, the value of the mean indexes P, Q and R of the compounds obtained according to the invention being equal to or less than 10% lower than that of the indexes .S ". T and U of the starting materials.

The method of the invention is preferably carried out at temperatures between 120 ° and 320 ⁰ C and under pressures to atmospheric pressure, optionally as a diluent gas for fluorine, an inert gas such as nitrogen. Helium or argon is used.

The method of the invention leads to the following results:

1) Elimination of the oxygen bound in peroxide form, possibly in the starting materials may be present;

2) Elimination of chemically reactive terminals Groups of acidic nature, such as -COF-. Ketone or hydrous ketone groups;

S) Conversion of neutral i-ndsian groups only

Wasscrstol'lgehali.wic -Cl ₂ II uiul -CFII CII, -

( iruppcii. in perHuorierte neutrals (iruppen.

All of these conversions lead to the overall result that the conversion products with fluorine Figenscliaften very great thermal stability and very great chemical inertia combined with very good dielectric and lubricating properties be awarded.

The perfluorinated polyithers and their mixtures according to the invention are in the form of colorless liquids. the one boiling point. Density and viscosity owners .. which increase by increasing their average molecular weight; in general, their boiling point is between 50 ° C. and more than 350 ^° C. at 0.1 mm Hg.

The mixtures according to the invention are dielectric in the form of relatively low-boiling distillation cuts or fractions as solvents Media, hydraulic fluids and inert fluids used for heat transfer. Fractions of mixtures of products with a higher molecular weight are used as lubricants high temperatures and in contact with decomposing agents, plasticizers and dielectric oils particularly suitable.

In general, the polyether starting material is which is exposed to the reaction with fluorine, at the reaction temperature in the liquid state and can be used as is without any dilution.

For the practical implementation of the implementation, the simplest way of working is to use a gaseous fluorine stream either pure or diluted with an inert gas in a liquid phase at the for the reaction selected temperature to send polyethers, preferably for this it is ensured that by some system a good contact between the gaseous phase and the liquid reaction phase is achieved.

The reaction is carried out until complete or in any way satisfactory Conversion of the original end groups to Perfluoralkylgruppeii is achieved and optionally existing peroxide groups have completely disappeared.

The elevation reaction can be carried out according to a continuous Working method can be carried out by feeding a liquid polyether phase to a reactor, through which a gaseous fluorine stream is passed; in this case, the reactor can achieve a good Contact between the reaction pieces inside a filling made of inert material, such as. B. Monelmctall. Nickel or platinum, which is completely inert in the fluorination reaction and has no catalysis whatsoever exercises included.

In this fluorination stage, various reactions take place in the terminal groups. Some of them can e.g. B. shown by the approaches below, where the symbols P / - have been adopted around a chain of perforated polyether or To show mixed polyethers of any length.

P ₁ -O
Ρ, - O
P, —O

P ₇ -O-

CF ₂ -COF
CF ₂ -COOH
CF-COF

CF ₃

CF-COOH
CF ₃

- Ρ, —Ο — CF, + COF ₂

F ₂

—► Ρ, —Ο — CF, + CO ₂ + HF

F,

- * Pj-O-CF ₂ -CF ₃ + COF ₂

P, -0-CF ₂ -CF ₃ + CO ₂ + HF

P, -O-CF ₂ -O-COF - * - P, - O - CF, + COF ₂ + '/ ₂ O ₂

F,

Ρ, - Ο — CF ₂ -CF-O-COF-Pj- Ο - CF ₂ -CF ₂ -CF ₃ + COF ₂ + '\ O ₂

CF _{3 h} ,

Pj, -O-CF-CF ₂ -O-COF-P ₇ -O-CF (CFj) ₂ + COF ₂ + ¹ I ₂ O ₂

CF ₃

Pj-O

P _x -O

P _x -O

CF ₂ -C (OH) ₂ -CF _{3 -P f} -O-CF ₃ + CF ₃ -COOH + HF

F ₂

CF ₂ -CO-CF ₃ - * Ρ, -Ο-CF, + CF ₃ -COF

F ₂

CF ₂ -CO-CF ₃ - ► Pj- Ο - CF ₂ - CF ₂ - CF ₃ + ¹ Z ₂ O ₂

Pj-O-CF ₂ H-Pj- Ο-CF ₃ + HF

F ₂
P _x -O-CFH-CF, -P _f -O-CF ₂ -CF ₃ + HF

709 622/60

«748

Except through reactions of this kind, which refer exclusively to the terminal group of the molecules, fluorine can also be used at high temperatures inner bonds of the polyether chains react.

However, as has been observed, the fluorination reaction carried out under the above-mentioned conditions is quite specific for the end groups, and the extent of the reactions which cause a break in the internal bonds of the molecules or also a separation of the side group —CF3 can be insignificant or in any case very low values are reduced; in practice, the reaction in question results in perfluorinated polyethers and mixed polyethers which contain only terminal perfluoroalkyl groups which have practically the same or only slightly lower molecular weight as the starting polyether. In addition, it was also possible to establish that the previous observation also applies if the starting polyether has a certain oxygen content in the peroxide form, i.e., for example, up to 1 atom of peroxide oxygen for every 10 atoms of ether oxygen present in the chain, even if after treatment with fluorine the Polyether does not contain any trace of such peroxide groups. The fluorination does not produce any significant changes in the mutual proportions between the various fluorinated units forming the polyether chains. In other words, with reference to the general formulas given above, the values of the indices P, Q and R with respect to the molecules of the polyethers and mixed polyethers after the fluorination are practically the same or only slightly smaller up to a maximum of 10% than the values of the corresponding indices 5, Γ and £ 7 of the starting polyethers, while the index V in the end products assumes the value zero.

This fact is due to the high reaction temperature and the well-known chemical reactivity of fluorine, for example the bonds of carbon to carbon, which generally makes its reactions scarcely become specific, surprising.

As already stated above, the original terminal groups are converted to perfluoroalkyl radicals by the action of fluorine at high temperatures, and the products obtained in the form of pure chemical compounds or in the form of their mixtures are always perfluorinated polyethers or mixed polyethers of linear structure, which at the end of the Chain perfluoroalkyl radicals bound to an atom of ether oxygen with a content of 1-3 carbon atoms. In general, however, it has been observed that the terminal trifluoromethoxy group —O — CF ₃ predominates in the products, either because it is usually already present in the products subjected to fluorination and in this case predominantly in the form of a

CF ₃ -O — CF ₂ —CF — O- group,

CF ₃

CF ₃ -O — CF ₂ -O- group or

CF ₃ -O-CF ₂ -CF ₂ -O-GmPPe,

or because it was formed during fluorination. and in this lall it lies predominantly in the form of

CF, - OCF - CF ₂ -O-

before. if in the starting material - CjFbO-F.inhcitcr were present.

The fluorination process of the invention is preferably carried out on mixtures of compounds applied and therefore results in mixtures of perfluorinated polyethers and mixed polyethers. It is possible from these

is to separate mixtures with physical means, such as fractional distillation or gas chronuitography, pure chemical compounds, ie compounds that are characterized by a precise chemical formula. In many possible fields of application, however, this is not necessary and the compounds of the invention can be used in the form of mixtures of compounds, optionally after simple treatments, e.g. B. a distillation, which result in a separation of cuts or fractions with the desired mean characteristics. These mixtures can obviously contain compounds which differ with regard to the value of the indices P, Q and R and the structure of the groups A 'and Y :

in addition, the various compounds can differ from one another if one or both indices P and R are not equal to zero, the abovementioned indices remaining the same, specifically with regard to a different distribution of the perfluoroalkylene units along the chain. In general, the mixtures of polyethers and mixed polyethers according to the invention can be characterized on the basis of the mean values of the indices P, Q and R and the presence of the various terminal groups in certain mutual proportions.

The elements for a structural identification of this type can e.g. B. from a combination analytical (molecular weight, elementary

4s settlement) and spectroscopic values (nuclear magnetic Resonance, infrared spectrum).

For information, some spectroscopic values are listed below that are necessary for the determination the structure of polyethers and mixed polyethers and

their mixtures of the type indicated are useful.

These values or information relate to absorptions in the infrared spectrum and resonance bands in the nuclear magnetic resonance spectrum, it being assumed that this is associated with the presence

given end groups of the chain and given structural units of the same chains in connection can be brought.

For example, in the infrared absorption spectrum, the following relationships can be considered

to be pulled:

-CF ₂ -COF

-CF-COF
CF ₃

in connection with 1,884 cm '

in connection with 1,876 cm '

748

11th

-CF-CF ₁ -O-COF

-CF ₁ -CF-O-COF

CF,
COOH
CF ₂ COCF,

in connection with 1,894 cm '

in connection with 1,778 cm '12

CF ₂ C (OH) ₂ -CF, in connection with 3.612 er O CF ₂ H in connection with 3.400 ei

-OCIII Cl ', in conjunction with 3, (K) O er

At which Kesonan / spekiruni were made by fluorine Resonances in the indicated areas have been associated with fluoriitonia, too

in connection with 1.803 cm 'io indicated next to it (inippen include:

Parts per million laus CKCI,)

Quantity

of fluorine atoms (group or function

+ 80 5

+ 49 + 51 2

+ 99 1

+ 58
+ 51.9
+ 53.6

+ 59
+ 82
+ 130
+ 81.5
+ 11.6

+ 12.3

+ 75.7

+ 83.2
+ 84.7
+ 144.5

2n (n> 2) 3

+ 15.1 -13 1 -12.5 + 1 -26.4 1

2 3 1 -0-CF ₂ -CF-ΟΙ CF,

- Ο— CF ₂ -O—

CF ₁ -O-CF-O-

CF ₁

(CF ₂ -O-) ,,
CF ₃ -O-CF ₂ -CF- Ο -

CF,

CF ₃ -Ο —CF-CF, -ΟΙ
CF ₁

CF ₁ -O-CF ₂ O-

- Ο -CF ₂ -CF ₂ -O-CF ₂ -O-CF ₂ -CF ₂ -O-

- Ο— CF ₂ -O-CF ₂ - Ο - CF ₂ -CF ₂ -O-

CF ₁ -O-CF-O-

CF ₃

-CF ₂ -O-CF ₂ -COF CF ₃ -CF ₂ -CF ₂ -O-CF ₃ -CF ₂ -CF ₂ -O-CF ₃ -CF ₂ -CF ₂ -O-FOC-O-CF-CF ₇ -O-

CF-, FOC-O-CF ₂ -CF-O-

CF ₃

FOC-O-CF ₂ -O-FOC-CF ₂ -O-

FOC-CF-ΟΙ CF ₃

-CF-O-CF ₂ -COOH

CF ₃

CF ₂ -HO-CF ₃ -CFH-O-CF ₃ -CFH-O-

continuation

IViIe per million I.his (ICI ₁ I

An / all] <iriippe iiilcr I unklioii

the l'liinraloinc

O CT ₂ -O CT ₂ COI
- Ο — Cl-, O CT, COOII CF ₂ HO Cl Cl-, O

+ 74.8
+ 82.8
+ 87.6
+ 89.3

CF ₁ -CO Cl ₂ -C) CT, -C (OII), Cl, CF ₁ -CF ₂ O CF, (CF ₂ -CI ', ()! ">

In addition, in the resonance spectrum of the 20 -OCI ₂ II or —Ο - Cl H --Cl- "1 in connection

Wasserstol'fiitoms the resonances in the areas of brings.

t> .3 and 5.75 parts per million (from TeirameihyKilan) with

in the presence of the terminal group olel'iiiepo \ idpolyiiiher of the general formula

XCF ₁ -CT ₇ - C)

CF ₂ -O

X: X

,, - CF-CI - C) -CF,

X
Cl

C)

CF ₂ X

in the ;; and in positive integers including 0, n + m are the number of polyether groups with the structure

-CT (X) -CF ₂ -O-

in the molecule and X represents a fluorine atom or a Pcrfluormklhylgruppc.

Compared to these known products there is the advantage of the perfluorinated polyethers according to Application therein that the molecular trowel of at least 2 different Perfluoralkylcnoxycinheiten. mainly

- (CF ₂ -CT (CFj) -O) - and -CT ₂ -O-

is formed, and thus a copolyether chain. Products of this type are characterized by a very high chemical and thermal stability. Furthermore, the presence of a _{-CF 3} -O unit, compared with the homopolyethers of hexafluoropropyneoxycinicites alone, increases the ratio between the number of -C-O bonds in the chain versus the -CC bonds. It is known that this results in a lower rigidity in the molecular structure and therefore products are obtained, i.e ^.; e have a lower viscosity for the same molecular weight and a lower volatility for the same viscosity.

Another advantage is the lower fluctuation of viscosity with temperature and lower pour point. It should also be noted that —C-C bonds have a noticeable energetic resistance to represent the rotation in contrast to the -C-O bonds. Accordingly, the higher ratio of —C — O to —C — C bonds in the main chain can be considered as Reason for the said advantages of the connection can be seen after registration.

Completely the same effect can be observed with copolyethers based on -C) F ₁ ) O- and _{-CF 2} O units compared to homopolyethers which consist solely of.

is B e i s ρ i e 1 1

The terminal acid group-containing PoIyätherausgangsverbindungen be obtained by the following procedure: 1,040 g of C) Fi ,, the liquid state at a temperature of -6O ⁰ C to -55 ° C in a cylindrical stainless steel vessel having a capacity of 1.31 and an inner diameter of 70 mm are held for 2 hours with an ultraviolet ray lamp (type Hanau TQ 8i - 3.8 Walt with a wave lye emission of 2000 - 3000), which is contained in a quartz case with an outer diameter of 20 mm and axially in the middle of the reactor is attached, irradiated. During this time, a current of 40 l / hour is passed through the liquid phase of CsFt. Oxygen under atmospheric pressure, which is cooled at the outlet end in a reflux condenser at -80 "C.

At the end, the excess CsFfc and the volatile reaction products are removed by heating to 80 ° C under a vacuum (10 mm HG). In this way, 94 g of a residue in the form of a colorless viscous liquid with an average molecular weight of 6000 and an element together th mrnsetzung corresponding to the formula CFuggOoje preserver. the content of active oxygen (iodometrically <method) corresponds to 0.47 g of active O ₂ / 100g Produki based on these values and see spectroscopic analysis of kciTimagnetischen resonance translucent, the average chemical structure represented by the formula

WO- (C ₃ F ₆ O) S- (CF ₂ O) ₇ (O) VZ
to be expressed in the IV predominantly -Cl

5

15 ^ 16

hirslclll. albeit small amounts

CF ₃ -O-CF- / the -CF ₃ Z-CF-O-CF ₃ ratio is about 20: 1 \

CF ₃ I CF ₃ j

-if available :: md. T / S = 0.02; V / (S + T + \) = 0.05; and Z predominantly consists of the —C / F group,

jie in the two places

-CF ₂ -CF-OCOF and CF-CF ₂ -OCOF

CF ₃ CF ₃

is available. Small amounts of the terminal groups

-CF ₂ -O-COF. —CF-COF and CF ₂ -COF

CF ₃

are also present in a ratio of 3: 1.

50 g of this mixed poiyether are introduced into a small Monel reactor with a capacity of 75 cm ³ , which is provided with a drip tube and a reflux cooler; in these a current 2 <of 10 l / h. Fluorine, which with 40 l / h. Nitrogen is diluted. First blown in at room temperature and then with gradual heating to 250 "C in a time of about 2 hours: the reaction is continued at this temperature for 10 hours.

In the end, 40 g of perfluorinated product were obtained which had a molecular weight of 5500 and a Elemental composition according to the formula CF2O0J4 and has neither active oxygen nor Contains acid functions.

The spectroscopic examination shows that the ratio of the units C3F _b O / CF ₂ O is practically unchanged with respect to that of the starting product and that the main groups consist mainly of the two species

CF ₃ -O-CF ₂ -CF-

CF ₃ (already present in the starting product) and

40 minor amounts of perfluoroalkoxy groups and predominantly

CF ₃ -CF ₂ -CF ₂ -O- and CF ₃ -CF ₂ -O-

present.

The reaction product is in the form of a colorless transparent liquid mii a viscosity of 430 centistokes at 20 ⁰ C, a density of 1.889 (g / ml) at 25 ° C and a Viskosi'Stsindex (ASTM 2270/64) of the 123rd

Fractional distillation under a high vacuum divides this product into three fractions; the first fraction of 15% by weight of the total amount has a distillation temperature of up to 200 ° C / 0.1 mm Hg with a viscosity of 35 centistokes at 20 "C and a density of 1.86 at 25 ° C; the second fraction of 25% by weight. -% with a distillation range of 200-290 C70.1 mm Hg has a viscosity of 250 centistokes at 2OC and a density of 1.892 at 25 ° C; the third fraction with a distillation temperature of more than 290 ° C / 0.1 mm Hg has a viscosity of 1700 Centistokes at 20 ⁰ C and a density of 1,905 at 23 ^ C.

The viscosity data of the three fractions mentioned at temperatures of 55.56 ° C and 116.7 ° C. the corresponding viscosity index (ASTM 2270/64) and

CF ₃ -O-CF-CF ₂ - 45 Besides that the Pour point (ASTM 2 D-97/57) are ⁰ C 116.7 "C as follows: Flow
Point C. CF ₃
exist.
In addition to the end groups B e i s ρ Kinematic
Viscosity
at at (CS) Viscose
activity
index C. 55.56 3.2 C. CF ₃ O-CF-O- 50 (it) 11.0 -70 ^c CF ₃ I. fraction 16 42.0 52 -37 ^C Il fraction 85 106 -26 ^C which are present in the starting material III fraction 520 134 iel

100 g of the mixed polyether. _{obtained by reacting C 3} Fe and O ₂ as described in Example 1 are heated to a temperature of 250 ° C. for 10 hours and the gaseous and volatile liquid products formed in this way are removed. This treatment removes all of the peroxide oxygen as CF ₃ -COF-COF ₂ and continues to remove the end group after the subsequent reactions

-0-CF ₂ -CF-O-COF O- CF ₂ -CO-CF, 4-COF ₂

egg;,

- O —CF-CF ₁ -O —COF-

converted

CT,

-O— CT- COF + COF,

CT,

709 622/60

In the end, 87 g of compounds are obtained which are neither peroxide nor practically terminal Groups of the —O — COF type of fluoroformate contain. The molecular weight determinations and the spectroscopic analysis show that they predominantly the formula

CF ₃ O- (CiF ₆ O) ₅ - (CF ₂ O) T-CF ₂ -CO-CF ₃

with a ratio T / S = 0.02 and an average molecular weight of 7OO0.

50 g of this product are in the same device that is described in Example 1, with a 20 l / h. Nitrogen diluted stream of 201 / hr. Treated fluorine at 250 ° C for 10 hours. At the end, 48 g of a perfluorinated product are obtained with a structure analogous to that of the starting product, with the exception of the terminal ketone groups which lead to terminal perfluoroalkoxy groups CF ₃ O- and CF ₃ -CF ₂ -CF ₂ -O- in a ratio of approximately 2 : 1 appear to be converted.

An analogous experiment was carried out starting from 40 g of the same polyether with terminal ketone groups, to which, however, an amount of water of 2% had been added beforehand at room temperature, after it had been stirred for 30 minutes at room temperature, to convert the ketone groups into hydrous ketone groups of the type -CF ₂ -C (OH) ₂ -CF ₃ to transform. 37 g of perfluorinated mixed polyethers with the same characteristics as the previous products were obtained after reaction with fluorine.

Example 3

100 g of the polyether product obtained by combining C ₃ Fb and O ₂ as described in Example 1 was treated with 10 g of 85% KOH while stirring at 150 ° C. for 3 hours and at 250 ° C. for 5 hours to cause the formation of salt formation and decarboxylation reactions.

At the end, 85 g of the liquid product was filtered from the remaining salts and analyzed. It it was found that it consists of a mixture of compounds of the middle formula

CI ₃ O - (C, F "O) a- (CF ₂ O) τ- L

in which T / S = 0.03 and Z consists of the groups -CF ₂ H and -CTH-CF ₃ in a ratio of 4: 1. The average molecular weight was 5500.

50 g of these compounds were in the reactor already described in Example 1 with a flow of 20 l / hour. Treated fluorine at 150 ° C for 10 hours. 49 g of perfluorinated mixed polyethers were obtained with practically the same structure as the starting products, but in which the hydrogenated end groups were replaced by perfluoroalkyl groups —CF ₃ , —C2F5 (and C ₃ F ₇ - to a lesser extent).

Comparative tests for the resistance wedge to oxygen at temperatures of 250 - 350 "C / eigen, fio that this perfluorinated polyether is markedly more stable than the one containing hydrogenated end groups Raw mixed polyether.

The ones with the original material and the ones received Compounds carried out thcrmogravimelrischcii (15 Tests at a heating rate of 5 "C per minute show that the water has an oxygen atmosphere at a temperature of 365 "C, while the perfltioriene product has a weight loss of 1% under the same conditions / eiut.

Example 4

The same reaction of the photochemical oxidation of liquid CIFB is at a temperature of + 22 "- carried out at 24 ° C and under a pressure of 7 After evaporation of unreacted C ₃ F ₆ and of the volatile products at 8O ⁰ C 135 are g. These polyethers have an elemental composition corresponding to a formula CF1.95O038 with an active oxygen content of 0.8 g / 100 g polyether and a molecular weight of about 1000.

A general formula results from the spectroscopic examination

W- (C ₃ F ₆ O) ₅ - (CF ₂ O) ₇ - (O) VZ
in the 775 = 0.72, V / (S + T + \) = 0.08, W

CF ₃ O- and CF ₃ O-CF

in a ratio of 5: 1 and Z represents the predominant structures

-COF, -CF ₂ COF, CF-COF

CF ₃

represents.

50 g of this product are as described above with a 40 l / h. Nitrogen diluted fluorine flow of 201 / hr. implemented, gradually ^{heated to 250 0} C and then this temperature is maintained for 10 hours.

In the end, 40 g of polyether are obtained which, on the basis of spectroscopic analysis, only have perfluoroalkoxy end groups appear to have an average molecular weight of 1000 and practically unchanged Show the relationship between the various perfluoroalkylene units, but without peroxide groups. These compounds can therefore be represented by the formula

XO- (C ₃ FBO) Z- (CF ₂ O) ₀ -Y
be defined in the X and Y

-CF ₃ , -C ₂ F ₅ , -C ₃ F ₇ and CF ₁ -OCF-

CF,

mean, where all are present, but -CF ₃ and -C ₁ F ₇ predominate, the ratio Q / P = 0.7 and the sum of P + Qm is of the order of magnitude of 7.

Example 5

The same reaction of the photochemical oxidation of liquid CiFb is carried out at a temperature of -30 ", -25" C under a pressure of 2 al. According to F. nilerming of unconverted CF ₆ and the volatile products at 50 "C and 10 mm Hg, 260 g of mixed polyols are obtained. These have an analysis according to the formula CFi ^ On." a minimum molecular weight of 4000 and an active oxygen content of 0.8 g / 100 g of mixed polyols

The spectroscopic determinations agree with: in the prevailing mean formula

CF ₃ O- (C ₃ F _b O) s _{- (CF 2 O) r} - (O) _v -COF

in one, in which T / S = 0.05, V / (S + Γ + 1) = 0.08 and the terminal function -COF predominantly in the form of the two fluoroformate groups

-CF, -CF-O-COF

CF,

-CF-CF ₂ -OCOF

in a ratio of 4: 1. Smaller amounts
terminal groups

CF, -O-CF
CF ₃

and -CF ₁ -O-COF

-CF ₂ -CO-CF ₃ and - CF-COF

CF ₃

to convert in a ratio of 4: 1.
The remaining product is mixed with 45 g of 85% KOH

Treated for 5 hours at 250 C until the evolution of gas (CHFi and CO ₂ ) ceases. A neutral liquid mixed polyether (420 g) is obtained by filtering, in which terminal groups -CF ₃ O, -CF ₂ H and -CFHCF ₃ are present, the latter two being present in a ratio of 4: 1, while the two oxy-perfluoroalkylene units are present in the kets in a proportion equivalent to that of the crude acid product.

400 g of this neutral mixed polyether were subjected to a fractional distillation under a vacuum of Subjected to 0.1 mm Hg and divided into 6 fractions.

In each case 40 g of these fractions were with a flow of 20 1 / hour. pure fluorine at 150 ° C for 6 hours long treated.

After this treatment, spectroscopic analysis shows the absence and presence of hydrogen of perfluoroalkyl radicals, consisting predominantly of CF) -, the two types

CF ₃ O-CF-CF ₂ -

available.

500 g Mischpolyäther obtained in various Reaklionen of this type are heated at 250 ⁰ C for 4 hours to eliminate the Peroxydsauerstoff and Fluorformiatgruppen in the terminal groups

CF ₃

and

CF ₃ O-CF ₂ CF-CF ₃

as well as _{—C 2} F ₅ and -C ₃ F ₇ .

The ratio between the units C ₃ F ₀ O and CF ₂ O in the chain is unchanged after the fluorination. The table shows the characteristics of the various fractions before and after treatment with fluorine.

table

Physical properties of neutral mixed polyethers before and after treatment with fluorine

fraction Dcst. Area Viscosity 20 ⁰ C C. 25 (g / ml) after Mol-weighted after No. below 0.1 mm Hg Centistokes 1,823 1,140 ⁰ C before after \ / or 1,870 before 1,730 1 50-100 7.36 7.70 , 823 1,879 1,000 2,680 2 100-150 26.24 26.07 , 856 1,885 1,720 3,500 3 150-200 78.47 77.45 , 875 1,890 2,700 4,350 4th 200-250 152.32 150.10 , 883 1.901 3,600 6.750 5 250-300 279.50 239.06 , 889 4,600 6th > 300 823.90 786.76 , 900 7.100

example

The preparation of the starting polyether is carried out in the following manner. In a glass reactor with a cylindrical shape and a capacity of 800 cm ^J , which contains 500 cm ³ CF ₂ CI-CFCl ₂ ^{cooled to -10 0} C, which is irradiated with a Hanau TQ 81 ultraviolet lamp immersed in the liquid phase a stream of 201 / h C ₂ Ft and 401 / Sld. Blow oxygen for 3 hours. Then the supply of the reactants is stopped and the irradiation of the liquid phase is continued for a further 12 hours; at the end, after evaporation of the solvent, 19 g of a high-boiling liquid product with an element corresponding to the formula CF ₂ Oo ?; and a content of 0.4 g of peroxide oxygen per 100 g of product.

This polyether was heated for 3 hours at a temperature of 220 ° C, leaving 15.5 g of residue received, which unites 10 g after a distillation Fraction with a boiling point in the range before T) O-M) O "C at 1 mm Hg resulted.

An active oxygen content of 0.02 g per 100 g of product and an empirical formula CF ₂ Oo.7q were determined for this fraction; only the end

The equivalent groups CF1O— and —CF ₂ —COF appear to have a ratio of I; 1 to be present. The molecular structure consists of IT ₂ OF units around CF ₂ -CF ..- O units in a ratio of 4: I.

In a glass vessel with a capacity of 10 em ³ , which was provided with a dip tube and a reflux cooler with water circulation. 5 g of the product described above were subjected to a treatment with pure, gaseous fluorine, which was extended to a period of 6 hours, at a temperature of 200 ° C. below: worfcn.

3.2 g of a liquid, neutral product of the formula CF ₂ O ₀ Jb were obtained in which the ratio between the two units CF2O— and C2F4O— remained practically unchanged with regard to that of the starting product, while the chain-terminating groups were predominantly composed of CFj - to pass with very small amounts - C2F5 Example 8
Preparation of the sample

line pholochemische Oxydalionsreaklion is in the gaseous phase in a Pcrfluorpropylen is kugelglasgcfäß 5 provided quartz jacket 81 containing the I. ^ with a Hanau TQ an ultraviolet lamp having a capacity \> w. which is cooled with an external water circuit.

The reactor is with a flow of 40 l / h. charged to an equimolar mixture of C ₃ F ₆ and O ₂ ; at the outlet end of the reactor, the high-boiling products formed are separated off with cooling. The reaction is continued until 100 g of product have been obtained which is liquid at room temperature: it became

XO- (CF ₂ O) _t) - (C ₂ F ₄ O) «- Y

can be expressed, where X and Y mean - CFj and - C_> i in a ratio of about 10: 1, and the ratio R / Q = 0.25.

rails.

The polyether thus obtained has therefore found that it has an elemental composition quite a structure represented by the formula close to the formula CF ₂ O and in proportion

2: 1 from the oligomers of the two series

CFjO (CF ₂ O) _n -COI and CF ₃ O (CF ₂ O) _n -CF ₂ COF

besf chi. where η is between 2 and 15. A 30 g sample of this mixture of compounds is kept in a glass jar boiling at atmospheric pressure for 24 hours at initial boiling temperatures of about 100 ° C and final boiling temperatures of about 150 ° C.

During this treatment a large amount of CF ₂ O-CYES is removed and in the end 12 g of a mixture of polyethers, almost entirely from the oligomers of the series

CFi-O (CFjO) ₁₁ -CF ₂ -COF.

where /; has a value between 2 and 15. exist, reverberate.

A sample of 10 g of this acid polyether is in the device described above with a Treated flow of gaseous fluorine at a temperature of 120 "CfUrCInC for 4 hours.

In this way, 6 g of a mixture of neutral polyethers are made from the oligomers

CFiO (CF ₂ O) ₁₁ -CFi,
where π is between 2 and 10.

Example 7
Manufacture of the starting product

In the same reactor as in the previous example, 500 cm ^{1 of} CF ₂ Cl-CFCh, cooled to -5 ° C., were introduced and the irradiation of the liquid phase was started, while a gaseous mixture of 70 l / h. was blown in with a content of C ₂ F ₄ , C ₁ F ₆ , 0 ₂ in a ratio of 1: 1: 1.5.

After 4 hours, the Geszufuhr was discontinued, while the irradiation of the liquid phase was more than 15 hours was continued.

At the end, the solvent was evaporated and 41 g of a liquid product with an element composition corresponding to the formula CF ₂ OuW and a content of 0.12 g of hydroxide oxygen per 100 g of product were obtained.

The spectroscopic examination showed that the product of linear chains with the units CF ₂ O-. CF ₂ -CF ₂ -O- and CiF ₁₁ O- in a ratio of 2: 1: 3 with neutral end groups -CFi and CF ₃ -O-CF (CFiJ- as well as end groups of acidic nature with the structure

5 °

-CF ₂ -O-COF. -CI (CI () -CF ₂ OCOF,
-CF ₂ -CF (CIi) -OCOF. -CF ₂ -COI

considered.

This polyether was distilled and 15 g of a _sii fraction with a boiling point between 150 'and 220''C at 1 mm Hg were separated off.

A sample of 5 g of this product was described in the previous example, modalities of treatment with fluorine at a temperature of r, ₀ 250 ° C unlerwor of IO hours for a period of l's.

3.8 g of a neutral polyether were obtained, in the molecular ladle of which the units CT ₂ O ₁ C ₂ F ₄ O and CjFf ₁ O in a minimal ratio

I: 3

are present at the same time, the terminal groups only consisting of neutral and saturated pcrlluorier-1 i-ii groups exist.

Example 9

The preparation of the sample was carried out as follows:

In a cylindrical 600cm ³ -lesrcaklor with a quartz jacket. a dip tube and a reflux cooler kept at -75.degree. C., 500 g of CT ₂ CI ₂ . condensed at -50 ° C, introduced; then a 30 l / hour through the dip tube. Oxygen and 15 l / h. Tetrafluoroethylene is supplied to the existing gas stream, while irradiation is carried out with an ultraviolet lamp Hanau Q 81, which is immersed in the liquid phase. A bath placed outside the reactor maintains the temperature of -50 ° C. during the whole process. After two hours of irradiation, the solvent is removed by distillation down to 50 "C under atmospheric pressure and a residue of 67 g of a liquid polymeric product remains, which, according to elemental analysis, has a composition of 62.0% F and 19.b ()% C corresponding to the Formula CF2O0.70 and an active acid sulfate content of 3.10 g per 100 g of product.

2 l / h Tetrafluoroethylene supplied, the reactor being kept constant at a temperature of -35 ° C by means of an external bath. After four hours of irradiation, the excess fluoropropylene is evaporated under a vacuum and 290 g of a polyether oil are obtained which, according to iodometric analysis, contains 0.56 g of active oxygen per 100 g of product. According to the investigation of the nuclear magnetic resonance, the polyether consists of —C2F4 “and -CjlV units in a ratio of 0.26; - CF ₂ units were also found in smaller proportions, so that the molar ratio of CF ₂ Z (^ Fb + C2F4 is of the order of magnitude of 0.02.

The chain terminating groups consist of CT3O and - COF groups in practically equivalent mutual relationships.

This product is then exposed to the same ultraviolet lamps at room temperature under one irradiated slow nitrogen flow for 30 hours.

At the end, there are 275 g of a polyether with an active oxygen content of 0.05 g per 100 g Product received.

This polyether is in a glass flask at 250 "C

Heating continued for 3 hours, during which time it was 4% of its weight in the form of gaseous products (COF2) loses, and the peroxide oxygen content becomes further reduced to 0.01 g / 100 g product.

The ratio between the -C2F4O- and -C3F (, O units of the polyether treated in this way is 0.25: the terminal groups consist of CF3O-Gnippen of the two kinds

CF ₃ -O-CF ₂ -CF (CF ₃ ) and CF ₃ -O-CF ₂ -CF ₂ ,

Acyl fluoride groups

-0-CF ₂ -COF and -CF (CFj) -COF
and
Carbon groups -CF ₂ -CO-CF ₃ .

118 g of this product are ^{subjected to fluorination in a 200 cm 3} glass flask by applying a flow of 20 l / h. initiates pure fluorine at 250 ^° C. for 16 hours. At the end of the treatment are obtained 101 g of a neutral oil having a viscosity of 119 centistokes at 20 ⁰ C.

According to spectroscopic investigation of nuclear magnetic resonance, it contains terminal groups of the type

CF ₃ -O-CFj-CF (CF ₃ ) -CF ₃ O-CF (CF ₃ ) -CF ₂ .

According to the spectroscopic examination of the CF ₃ -O-CF ₂ -CF, -

nuclear magnetic resonance seems to link only end groups of the two types (and C ₃ F? - to a lesser extent). The relationship

55 of the units CF ₃ O-CF ₂ -O- and CF ₃ OC ₂ F ₄ O-

This product is irradiated for 40 hours at room temperature under a slow N ₂ syrup and then heated for 4 hours up to a temperature of 250 "C. At the end of this treatment, 48 g of an oily powdery ice with one hydroxide oxygen atom per 25 ether oxygen atoms remain, which shows by examination of the nuclear magnetic resonance that it consists of chains which _{contain the CF 2} O - and - C ₂ F ₄ O -EmIiCiICn in a ratio of 1: 1.3, the terminal groups from CF3O- and -CF ₂ COF-GiUPpCn exist in practically equivalent mutual relationships.

A sample of 96 g of the product obtained according to the procedure described above is subjected to fluorination in a 150 cN ³ glass flask by initially using a 20 l / h. Nitrogen diluted fluorine flow of 20 l / h. at a temperature of 250 ° C. for 15 hours and then for a further 5 hours at the same temperature 15 l / h of pure fluorine. At the end, 87 g of a completely neutral oil are obtained which does not contain any traces of peroxide groups and has a viscosity of 367 centislokcs at 20 ⁰ C.

The following fractions are obtained by allowing it to distillation under a vacuum of 0.2 mm Hg subjects:

I. Fraction: Kp. = 25-200 ° C-8.7g.

Viscous. = 8.46 centistokes 20 ° C.
II. Fraction: b.p. = 200-270 ° C-6.3 g,

Viscous. = 29.5 centistokes at 20 ° C.
Residue:

72 g; Viscosity = 604 centistokes at 20 ° C,

average molecular weight:> 10,000.
The viscosity data of the mentioned two fractions and the residue at temperatures of 55, 56 ° C and 116.7 ⁰ C, the corresponding viscosity index and the pour point are as follows:

Kinematic at Viscose Flow Viscosity 11b, 7C daily Point at (CS) index 55.5b C 2.1 (it) Parliamentary group 1 5.6 5.6 270 approximately -100 ⁰ C Group II 18th 92.7 300 approximately -100 ^c C Residue 345 342 approximately -70 ° C

with a ratio between the -CF ₂ O and C ₂ F ₄ O units of 1: 132.

Example 10

In the reactor described in the previous example, 700 g of hexafluoropropylene are condensed at a temperature of -40 ° C; then the ultraviolet lamp is switched on and a gas flow of 40 l / hour through the immersion tube. Oxygen and C ₂ F ₄ O / C ₃ F ₆ O / CF ₂ O

is approximately 1: 5: 1. It no longer contains any trace of oxygen bound in peroxide form.
The following fractions are obtained by subjecting it to distillation under a vacuum of 0.2 mm Hg:

I. Group: Kp = 73-200 ⁰ C 28%.

Viscous. = 210 centistokes at 20 ⁰ C
II. Fraction: bp = 200-284 ° C50%;

Viscous. = 167 centistokes at 20 ⁰ C
Residue:

20%; Viscous. = 861 centistokes at 20 ° C

709622/60

"J * _" -

5

The viscosity of the mentioned two fractions and the residue at temperatures of 55, 56 ° C and 116.7 ° C, the corresponding viscosity index and the pour point are as follows:

K incniii tables at Viscose Flow viscosity I 16.7 "C activity Point at (CS) index 55.56 "C 2.3 (CS) 8.65 Group I. 10.3 27.13 23 -60 ^c C Fraction Il 63.5 116 -47 "C Residue 290 131 -29 ° C

According to the procedures of Example 9, a few kilograms of a mixed polyether are prepared - CF2O and - C2F4O units in a ratio of 0.7: I and has CFjO groups as terminal groups, which results from the conversion of the originally present end groups due to the action of fluorine at a temperature of 200-250 "C results.

This liquid is subjected to distillation under a high vacuum, producing a fraction is obtained which has a boiling point of more than 250 'C at 0.1 mm Hg and a viscosity is characterized by about 500 centistokes at 20 ° C.

This latter product is used as a means for heat transfer in a chemical device (which operates without fracture for very long periods of time), reach a temperature of 380 ⁰ C and must be maintained without major changes than ± 2 ° C.

For this purpose a 20-liter container containing 30 kg of perfluoropolyether is made into the electrical Immersed resistors of 10 kW connected to an automatic heat control or regulation system are. The hot liquid is pumped through a flow rate of about 700 1 / h passed through the aforementioned chemical device and returns to the heating vessel back.

In this way a thermostat circuit is obtained that operates at high temperature without special Precautions works to separate the hot liquid from atmospheric oxygen.

After an operating time of 1700 hours at a temperature of 380 ⁰ C neither measurable losses of the fluid used can be due to evaporation or deterioration by Wärmeoxydation or formation of solid deposits in the pipes through which the liquid runs corrosion of the hot liquid in contact standing metal surfaces (stainless steel, Monel metal, nickel) observed.

A check of the liquid or the medium shows that at the end of the procedure the perfluorinated Polyether maintains the same viscosity values as it had before its use with a variation of ± 5%.

It concerns the problem of the fluorination treatment of a fluorinated polyether according to the method of To realize the invention with an amount of about 100 kg in practice, being easy to handle Devices are used in safe working conditions.

For this purpose, fluorine under atmospheric pressure from an Elcklrolygencrutor, a Monelfluoric tion reactor from a Monclgefäß with a capacity of 801, which is equipped with a stirrer s, a dip tube for introducing fluorine, since it is optionally mixed with nitrogen, an outer heating jacket, an outlet pipe , which is connected to a condenser for the condensation of low-boiling products, if they are present, and is provided with a cylindrical iron reactor which contains molten sulfur for the combustion of the possibly unreacted fluorine leaving the fluorination reactor, mainly to SF ₈ .

There, as stated above. Fluorine under atmo spherical pressure is used to make the hydrostat! see pressure to overcome the liquid phase present in the fluorination reactor is the outlet end de Sulfur reactor with a liquid ring suction pump

ία connected, which can generate a negative pressure, de

sufficient to allow the passage of the desired fluorine

amount due to a fluorination!

Determine or determine liquid.

Q. There are three problems for using a

such a device must be solved, whereby the selection of a suitable liquid or gaseous: Medium is required.

The first problem concerns the measurement of the amount of fluorine introduced into the reactor and the pressures ai

so the various points of the device: for this: flow meters and manometers are used in which the reading liquid, which must be resistant to the action of fluorine, consists of perfluoropolyether, which is stable and inert with respect to fluorine

.15 according to one of the previous examples would.

The second problem concerns the fluid that passes through it Circulation through the jacket of the fluorination reactor should be used for heating. For this purpose, e it is necessary to use a liquid or medium that is resistant to degradation by heat Heat oxidation extremely resistant and especially in the event of accidental breakage or damage the device where fluorine with the thermostati

see medium could come into contact is roughly borrowed. For this purpose a perfluoropolyether is used dium used the same as in the previous one! Application example is. This is also a guarantee or security against any problem related to the

such as internal corrosion, the formation of solid deposits or a change in properties Medium over time.

The third problem relates to the type or condition of the medium that is being used at the output

Device attached liquid ring pump is to be used ver; this liquid medium sol Overall, the following properties have practically no volatility chemical resistance exceptionally corrosive to the effects

M.ttel (COF ₂ , CF3COF, SF ₄ , HF), which are usually present in the sucked gas; very good lubricity to preserve the mechanical integrity ^; Ability to have a protective effect on the inner metal surfaces of the pump against the specified

sucked in corrosive chemical compounds

To solve this problem, a perfluorinated Polyether used by the method de Invention and made from perfluoroalkylene

5

27 28

heal - CjFt, - and - CF_> -, the product produced by Äthersauer- of Example 5 and was di

Atoms of matter are connected to one another, in a viscosity of 750 centistokes at 20 ⁰ C ki

There is a ratio of about 15: 1 and is identified as a chain-end.

Low groups only perfluoroalkoxy groups with 1–3. After using the pump for 30 working hours

Contains carbon atoms. 5 with a total duration of 1000 hours were k

This perfluoropolyether was the residue of a defect on the inner metal surfaces of the pump

observed below 0.1 mm Hg up to a temperature of 290 ^u C of the composition of the polyether,
carried out distillation of the process

! 4O

Claims (5)

Patent claims: 1. Perfluorinated polyethers of homopolymeric or copolymeric nature and their mixtures the general formula in the -C ₃ Fb and -C2F4- perfluoroalkylene groups of the structure -CF ₂ -CF-CF ₃ or -CF ₂ -CF, - represent, and the three different perfluoroalkylene units are randomly distributed along the chain, P, Q and R are mean indices of the composition and only P and / or R can be equal to zero, the sum P + Q + R has a value of 2-200 , the ratio of the indices P / Q + R has a value of 0-50, the ratio R / Q has a value of 0-10, X and K chain-terminating residues -CF ₃ , -C ₂ F ₅ , -C ₃ F ₇ -CF-O-CF ₃ , CF ₃ with the restriction that both end groups are -CF ₃ if the two indices Fund R are equal to zero, are the same or different from one another and -CF ₃ OdCrC ₂ FSbCcIeUtCn if only the index P is equal to zero, and finally if the Index F has a value other than zero, the two end groups can be the same or different from one another and - C3F7, -C ₂ F ', or -CF ₃ or one of them CF ₃ -O-CF- CF 4 ¹ S can be. 2. Process for the production of perfluorinated polyols and mixed polyethers which do not contain peroxide oxygen and their mixtures of the middle formula X (HC ₃ F ₁₁ O -) ,, - (- CF ₂ O- J ₀ HC ₂ F ₄ -O- in the X, Y, P, Q and /? have the meaning given in claim 1, characterized in that pure fluorine or fluorine diluted with an inert gas up to a fluorine content of 10 vol .-% under pressures between 0.2 and 10 atm and at a temperature of 100-350 ° C with polyethers and ( _{) 0} mixed polyethers or their mixtures with the mean general formula WO (-C ₃ F ,, O), s · ■■ (CF; OI _7-1 ^ HC ₂ F ₄ -O -) "- (- () -), · -Z converted, in the W and / terminal residues represent, with one —CF ₃ , CF ₃ - O — CF-, -COF, CF ₃
-CF ₂ -COF, -CF-COF, CF ₃
-CF ₂ -CO-CF ₃ , -CF ₂ -C- (OH) ₂ -CF ₃ ,
-CF ₂ H and -CFH
CF ₃ represents when the index S is different from zero, while when S is equal to zero, it only represents _CF ₃ . -COF, -CF2-COF and -CF _{2 is} H, and the other is terminal -COF, -CF ₂ -COF, -CF-COF, CF ₃ -CF ₂ -CO-CF ₃ . -CF ₂ -C (OH) ₂ -CF ₃ ,
-CF ₂ H and -CFH CF ₃ represents when the subscript S is different from zero, while such a different end group when 5 is equal to zero. represents -COF, -CF ₂ -COF and CF ₂ H only. (- 0 -) represents an oxygen atom distributed arbitrarily along the chain and bonded in the peroxide form to the various oxyperfluoroalkylene units, S, T, LJ and V are mean indices of the composition, where S. U and V can be zero, the sum 5+ T + {/ has a value of 2-200 and more, the ratio of the indices S / T + U is between 0 and 50, the value of the ratio L // T0-10, the ratio U / S + T + LJ + 1 is between 0 and 0.1 and the index V is equal to zero when S and U are equal to zero, the values of the mean indices P, Q and R of the polyethers obtained according to the invention being equal to or less than 10% of those of the indices 5, T and LJ are the starting materials. 3. The method according to claim 2, characterized in that the reaction is carried out at a temperature between 120 ° and 320 ⁰ C under pressures around atmospheric pressure. 4. The method according to claim 2 and 3, characterized in that there is used as a diluent for Fluorine uses an inert gas. 5. The method according to claim 4, characterized that nitrogen, helium or argon is used as the inert gas. Polyethers and mixed polyethers were already fluorinated, possibly also containing l'eroxydbi'ückeii described the reactive or hydrogen-containing groups at the ends of their chains, such as