Hydrofluoroether Composition and Method for Preparing the Same

Abstract

One or more compounds of formula (I): CFHX-CF2-O-R-O-CF2-CFHX (I), one or more compounds of formula (II): CFHX-CF2-O-R-OH (II), wherein - R in formula (I) and (II) is independently selected from C2-C10 divalent linear or branched alkyl optionally containing an oxygen heteroatom involved in a ring, aromatic ring and / or ether bond, - X is selected from halogen, H, Rf, where Rf is - a C1-C8 fully or partially fluorinated linear or branched alkyl optionally containing a ring, or - a C1-C3 fully or partially fluorinated alkoxy, two examples of X in formula (I) are the same or different, preferably the same, - the amount of one or more compounds of formula (II) is 0.002 to 5% by weight of one or more compounds of formula (I), a liquid composition containing the same.

Description

Technical Field

[0001] The present invention relates to a hydrofluoroether composition that can find use as a solvent. The present invention also relates to a method for preparing said composition.

[0002] This application claims priority from European Patent Application Publication No. 22181823.0, filed in Europe on June 29, 2022, the entire content of which is incorporated herein by reference for all purposes.

Background Art

[0003] Various methods for producing hydrofluoroethers from difunctional alcohols are known in the art. US Patent No. 4208081 (Du Pont) describes the preparation of hydrofluoroethers using ethylene glycol and tetrafluoroethylene (TFE) in a diethyl ether solution. However, the reaction is not complete because two reaction products are formed in approximately equal amounts, with both -OH groups of ethylene glycol being converted to ether groups in one case, and only one of the -OH groups of ethylene glycol being converted to ether while the other remains as a free hydroxyl group in the other case.

[0004] Russian Federation Patent No. 1810324 to Natalya Guseva reports the preparation of hydrofluoroethers from the reaction between ethylene glycol and TFE in a diglyme solvent in an anhydrous process in a 78% yield.

[0005] Solvents based on hydrofluoroethers are very advantageous compared to alternative materials available on the market because they have a low GWP (global warming potential), low flammability, and are thus safe and easy to handle. However, hydrofluoroethers generally have a relatively low polarity, which limits their scope of applicability in any case. On the other hand, when hydrofluoroethers are mixed with other more polar solvents, the composition may become incompatible with certain materials. Therefore, there is a need for solvent compositions that have all the advantages of hydrofluoroether-based solvents, including the same material compatibility, in combination with a wider range of applicability for materials that can be solubilized. The compositions of the present invention have a precisely adjusted increased polarity while maintaining all the properties of the hydrofluoroether-based solvents as such, and as a result, have a wider range of applicability as solvents than pure materials, while at the same time retaining all the advantages of using hydrofluoroether-based solvents.

[0006] There is still a need for compositions that can be easily prepared using a simple and high-yield method. The present invention also relates to such a method.

Summary of the Invention

[0007] The present invention relates to one or more compounds of formula (I): CFHX-CF2-O-R-O-CF2-CFHX (I) and one or more compounds of formula (II): CFHX-CF2-O-R-OH (II) wherein - In formulas (I) and (II), R is independently selected from C2-C10 divalent linear or branched alkyl optionally containing an oxygen heteroatom involved in a ring, aromatic ring and / or ether bond, - X is selected from halogen, H, Rf, where Rf is -- a C1-C8 fully or partially fluorinated linear or branched alkyl optionally containing a ring, or -- a C1-C8 perfluorinated linear or branched alkyl -- a C1 to C3 fully or partially fluorinated alkoxy selected from, and two instances of X in formula (I) are the same or different, preferably the same, - the amount of one or more compounds of formula (II) is 0.002 to 5% by weight of one or more compounds of formula (I)) relates to a liquid composition comprising.

Mode for Carrying Out the Invention

[0008] Accordingly, an object of the present invention is to provide a compound of formula (I): CFHX-CF2-O-R-O-CF2-CFHX (I) one or more compounds according to, and Formula (II): CFHX-CF2-O-R-OH (II) one or more compounds according to to provide a liquid composition comprising.

[0009] In the composition of the present invention, the total amount of one or more compounds of formula (II) is 0.002 to 5% by weight, preferably 0.005 to 3% by weight, more preferably 0.01 to 2% by weight, and most preferably 0.05 to 1% by weight of the total amount of one or more compounds of formula (I).

[0010] In formulas (I) and (II), - R is a C2-C10 divalent linear or branched alkyl which may contain an oxygen (O) heteroatom involved in a ring, aromatic ring or ether bond. R is preferably a C2-C6 divalent linear alkyl not containing an aromatic moiety. More preferably, R is -CH2-CH2-, -CH2-CH2-CH2-, -CH2-CH2-O-CH2-CH2-, -CH2-CH2-O-CH2-CH2-O-CH2-CH2-, -CH2-CH2-CH2-O-CH2-CH2-CH2-, -CH2-CH2-CH2-O-CH2-CH2-CH2-O-CH2-CH2-CH2- is selected from. R in the compounds according to formulas (I) and (II) can be the same or different, preferably the same. - X is halogen, H and R f is selected from. When X is halogen, it is preferably Cl or F. R f is optionally ring-containing, a C1-C8 fully or partially fluorinated straight-chain or branched alkyl or a C1-C3 fully or partially fluorinated alkoxy selected from. When X is R f is, preferably, R f is a C1-C3 fully fluorinated alkyl, and even more preferably -CF3). In a further preferred embodiment, X is selected from F, Cl and CF3, most preferably F.

[0011] In the composition of the present invention, the total amount of the compounds according to formulas (I) and (II) is preferably at least 50% by weight, more preferably at least 70% by weight, even more preferably at least 85% by weight, most preferably at least 90% by weight based on the total weight of the composition.

[0012] In one embodiment, the composition of the present invention consists essentially of the compounds according to formulas (I) and (II). "Consists essentially of" is intended to mean that the total amount of the compounds according to formulas (I) and (II) is at least 95% by weight, preferably at least 97% by weight, most preferably at least 99% by weight based on the total weight of the composition.

[0013] The composition according to the present invention can be prepared by any method known to those skilled in the art, for example, by mixing one or more compounds according to formula (I) with one or more compounds according to formula (II).

[0014] A preferred method for preparing the composition of the present invention is the reaction of a difunctional alcohol with a fluorinated olefin in a selected polar aprotic solvent in the presence of a basic catalyst. This method provides high yields, can be easily carried out under mild conditions without requiring environmentally harmful components, and enables the direct obtainment of the composition according to the present invention, which already has the desired balance among the compounds according to formulas (I) and (II), without the need to mix various components.

[0015] As will be apparent to those skilled in the art, one or more compounds according to formulas (I) and (II) are hydrofluoroethers. Hydrofluoroethers are defined as compounds having the general formula R-O-R', wherein at least one of R and R' contains at least one C-F bond and at least one C-H bond.

[0016] One way to form hydrofluoroethers is to react a chemical compound having at least one -OH group that is part of an alcohol or phenol group with a fluorinated olefin that can be partially or completely fluorinated. The reaction between the -OH group of the olefin and the C=C double bond can be explained as an addition to the C=C double bond in which one of the carbon atoms forms a C-O bond and the other forms a C-H bond.

[0017] In a first step (A) of the method of the present invention, a mixture is provided that includes one or more polar aprotic organic solvents and one or more difunctional alcohols.

[0018] The polar aprotic organic solvents suitable for use in the method of the present invention are polar aprotic organic solvents having a boiling point measured at atmospheric pressure (1 atm) of 60 to 170 °C, preferably 70 °C to 90 °C. Particularly suitable polar aprotic solvents for use herein are those having a nitrile group, and a particularly preferred solvent is acetonitrile.

[0019] Another essential component of the mixture provided in step A of the method of the present invention is a bifunctional alcohol. A bifunctional alcohol is a compound having two -OH groups, each of which is part of an alcohol group (i.e., it is covalently bonded to an aliphatic carbon atom that is not part of a carbonyl group -C=O).

[0020] These compounds typically correspond to the general formula, HO-R-OH (III) wherein R is defined as above for formulas (I) and (II).

[0021] Examples of bifunctional alcohols suitable for use in the present invention are ethylene glycol, di-ethylene glycol, tri-ethylene glycol, propylene glycol, di-propylene glycol, tri-propylene glycol, 1,3-propanediol, cyclohexanediol, cyclohexanedimethanol).

[0022] When forming hydrofluoroethers from bifunctional alcohols, various -OH groups can have different reactivities. In particular, after one or more of them have already reacted with a fluorinated olefin to form a first ether bond, the yield tends to be low. The method of the present invention makes it possible to obtain excellent yields using bifunctional alcohols.

[0023] In the method of the present invention, one or more bifunctional alcohols as defined above are provided in a mixture with one or more polar aprotic solvents selected as defined above. Such solvents are generally good solvents for the bifunctional alcohol, preferably such that the provided mixture is homogeneous. The relative amounts of the one or more selected polar aprotic organic solvents and the one or more bifunctional alcohols are preferably at least 1:1 by weight, preferably at least 2:1, more preferably at least 3:1, most preferably at least 4:1. Other solvents may be present in the mixture, but preferably the total amount of the one or more bifunctional alcohols and the one or more selected polar aprotic solvents represents at least 70% by weight, more preferably at least 80% by weight, even more preferably at least 90% by weight, most preferably at least 95% by weight of the mixture.

[0024] In step B of the method of the present invention, the mixture provided in step A is reacted with one or more fluorinated olefins in the presence of a basic catalyst.

[0025] Preferably, the fluorinated olefin is selected from among the perhalogenated olefins, more preferably selected from the group consisting of perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoropropyl vinyl ether, tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE), and hexafluoropropylene (HFP), and more preferably is TFE.

[0026] The fluorinated olefin can be initially charged to the reaction vessel or, advantageously, continuously supplied in the amount required during the reaction.

[0027] One or more fluorinated olefins have the following general formula CFX=CF2 (IV) (wherein, - X is selected from halogen, H, Rf, and Rf is -- optionally a C1-C8 linear or branched alkyl that is fully or partially fluorinated and optionally contains a ring, or -- a C1 to C3 fully or partially fluorinated alkoxy selected from) having.

[0028] The reaction of a compound having -OH with a fluorinated olefin can be outlined as follows.

Chemical formula

[0029] According to the definitions provided above, the group R1 may further contain other -OH groups (for example, in the case of a polyfunctional alcohol). Even in this case, since the resulting hydrofluoroether still contains the same -OH groups, it can further react with other molecules of the fluorinated olefin until all of the -OH groups have completely reacted and all of their oxygen atoms are involved in ether-type bonds.

[0030] The reaction can typically be carried out, preferably, in a sealed stirred reactor. The molar ratio between the -OH group and the fluorinated olefin is, in principle, stoichiometric, that is, having a complete reaction and no residual reagents, so the molar amount of the double bond from the olefin should be present as the molar amount of the -OH groups in the bifunctional alcohol. Of course, in this case where a bifunctional alcohol is used, each -OH group can react with a different olefin molecule, and as a result, for 1 mole of the bifunctional alcohol, 2 moles of the fluorinated olefin are required for the stoichiometric ratio. Although the stoichiometric ratio between the double bond and the OH group is ideal, the present invention can also be effectively implemented when one of the components is in a molar excess of up to 50%, preferably up to 30%, more preferably up to 20%, and most preferably up to 10%. When one component is in excess, the excess component is preferably the fluorinated olefin.

[0031] A basic catalyst can create a basic environment, that is, it can be any compound that can subtract protons from a reagent, thereby promoting ionic reactions. Preferred basic catalysts are selected from inorganic hydroxides (e.g., NaOH, KOH, LiOH, Ca(OH)2, Mg(OH)2), inorganic salts of weak acids (such as alkali metal phosphates or carbonates), and organic basic compounds (such as alcoholates). The most preferred basic catalysts are NaOH and KOH.

[0032] The amount of catalyst used is typically 5 mol% to 100 mol%, preferably 10% to 70 mol%, more preferably 15% to 50 mol% based on the total moles of -OH groups.

[0033] Typically, the basic catalyst is added to the reactor and added to the mixture provided in step A under stirring. Then, the reactor is typically sealed, and the fluorinated olefin is pumped to a pressure of 1 to 50 bar, preferably 2 to 30 bar, more preferably 3 to 20 bar, most preferably 4 to 14 bar in gaseous form. If the fluorinated olefin is in liquid form, the olefin can be introduced as a liquid, and if it remains in a liquid state at the reaction temperature, the reaction can be carried out at a lower pressure or even at atmospheric pressure.

[0034] The reaction typically starts immediately. Preferably, during the reaction, the reactor is maintained at a temperature of 20°C to 90°C, preferably 30°C to 80°C, most preferably 40°C to 70°C. The reaction time can vary depending on the temperature, pressure, and reagents used. Typically, 1 to 20 hours are required for the reaction to be completed.

[0035] After the reaction is completed, the reactor is typically evacuated to remove the excess fluorinated olefin. At this stage, the reactor contains a liquid reaction mixture containing one or more compounds of formula (I) and one or more compounds of formula (II) in combination with a polar aprotic solvent and residues of the basic catalyst.

[0036] One or more compounds of formula (I) and one or more compounds of formula (II) can be directly extracted from the reaction mixture using known techniques such as distillation (in optional process C of the present invention). However, since the reaction mixture obtained in step B still contains dissolved or dispersed solids, typically inorganic solids derived from the basic catalyst, direct distillation of the reaction mixture will accumulate undesirable solid deposits on the distillation apparatus, which may be acceptable on a laboratory scale but more problematic on an industrial scale as it may require frequent stoppages for equipment cleaning / recovery. Therefore, preferably, before extracting the hydrofluoroether by distillation, the reaction mixture is purified to remove catalyst residues and solid by-products.

[0037] In one embodiment, the reaction mixture is purified by extraction with water. In another embodiment, the reaction mixture is purified by evaporation and recondensation. These two embodiments are described in detail below.

[0038] Evaporation / recondensation method: In optional process D of the present invention, the liquid reaction mixture resulting directly from the reaction of step B is completely evaporated and recondensed in liquid form to obtain a purified reaction mixture thereby. Any available technique can be used to evaporate the liquid reaction mixture, for example, heating and vacuum can be used individually or in combination to evaporate the mixture. Conventional evaporation apparatuses (e.g., rotary evaporation apparatuses) can be used. Following the evaporation of the liquid reaction mixture, a solid residue is formed that contains the residual basic catalyst and salts obtained as by-products of the reaction that can be discarded or recycled.

[0039] The purified reaction mixture obtained in step D, unlike the reaction mixture obtained in step B, is of sufficient purity to be distilled in a conventional distillation apparatus. This is carried out in step E of the method of the present invention.

[0040] Water extraction method: In an optional step F of the process of the present invention, the liquid reaction mixture resulting directly from the reaction of step B is mixed with water and subjected to stirring and / or mixing to extract water-soluble impurities such as residues of basic catalysts and other impurities and by-products into the aqueous phase. The relative amounts of water and the reaction mixture used in this step are from 1:15 to 15:1 by weight, preferably from 1:5 to 5:1, more preferably from 2:1 to 1:2. The stirring can be carried out by any suitable technique known to those skilled in the art for extraction, and using a separating funnel or a similar device, the aqueous phase can be separated from the phase containing the aprotic polar solvent and the hydrofluoroether. The resulting phase containing the aprotic polar solvent and the hydrofluoroether, upon separation from the aqueous phase, constitutes a purified reaction mixture that is pure enough to be subjected to distillation in a conventional distillation apparatus in step G of the process of the present invention.

[0041] In all embodiments, distillation enables the separation of the hydrofluoroether from the solvent. The distillation can be carried out using conventional techniques and can be repeated if necessary to further purify the composition. Generally, the solvent is recovered by known methods for reuse.

[0042] The evaporation / recrystallization method described above is generally preferred over the water extraction method because the water extraction method produces large amounts of wastewater contaminated with system impurities and thus needs to be treated before disposal or reuse.

[0043] Both methods result in a composition according to the invention, wherein the composition consists essentially of one or more hydrofluoroethers of formula (I) and one or more hydrofluoroethers of formula (II) in the weight ratios required by the present invention.

[0044] The process of the present invention can be carried out under mild conditions and furthermore a very high yield of hydrofluoroether can be obtained.

[0045] If the disclosure of any patent, patent application, and publication incorporated herein by reference conflicts with the description of this application to the extent that it may obscure a term, the description shall control.

[0046] Herein, the present invention will be described in more detail in connection with the following examples, which are for illustrative purposes only and are not intended to limit the scope of the present invention. If the disclosure of any patent, patent application, and publication incorporated herein by reference conflicts with the description of this application to the extent that it may obscure a term, the description shall control.

Example

[0047] Analysis The product was identified by NMR (F-NMR and H-NMR) and GC and GC-MS analysis (GC using CP-WAX52CB column and CP-Sil8CB column for GC-MS peak assignment).

[0048] Example 1 - Ethylene Glycol + TFE + Evaporation 37 g of ethylene glycol, 211 g of acetonitrile, and 9.4 g of sodium hydroxide were placed in a 600 ml stirred Hastelloy reactor. After purging with nitrogen and evacuating to 0.3 bar, the reactor was heated to 50 °C and pressurized to 11 bar with TFE (tetrafluoroethylene) while stirring.

[0049] After stirring was stopped for 6 hours, the reactor was cooled, the residual TFE was purged with nitrogen, and then the reaction mixture was recovered, rinsed with an additional 106 g of acetonitrile, and drained.

[0050] Next, the collected reaction mixture (480 g) was transferred to a glass flask and evaporated under a vacuum of 1 mbar in a rotary evaporator while heating the flask to 90 °C. The solid by-products (14.5 g) were discarded, and a colorless and transparent purified reaction mixture (445 g) was collected.

[0051] Next, the purified reaction mixture was distilled in a glass distillation apparatus equipped with a condenser having a flask, a packed column, and a vacuum pump. The distillation was carried out by raising the temperature to 100 °C to 155 °C and reducing the pressure to 950 mbar to 50 mbar. The distillation product contained 142 g of the diether HCF2CF2 - O - CH2CH2 - O - CF2CF2H and 0.02 g of the monoether HCF2CF2 - O - CH2CH2 - OH (0.01 wt% of the diether). The yield of the whole process based on the addition amount of ethylene glycol was 90.3%.

[0052] Example 2 - Ethylene Glycol + TFE + Water Extraction 7231 g of acetonitrile, 2200 g of ethylene glycol, and 1290 g of sodium hydroxide were placed in a 22 L stirred Hastelloy reactor. After purging four times with nitrogen and evacuating to 0.3 bar, the reactor was heated to 60 °C and pressurized with TFE (tetrafluoroethylene) to a maximum of 3.5 bar while stirring, and TFE was continuously supplied to maintain the initial pressure. During the reaction, the reactor was cooled because the reaction was highly exothermic. Approximately 1300 g / h of TFE was consumed. After 7.5 hours, the reaction was stopped and the supply of TFE was stopped. The reactor was left at 60 °C, stirred, cooled to 25 °C, the excess TFE was purged with nitrogen, the reaction mixture was recovered and discharged.

[0053] Next, the collected reaction mixture was transferred to a 200 L container, washed with 150 L of demineralized water while stirring at 25 °C for 6 hours, and separated for 10 hours. Then, the bottom organic layer was separated (9300 g) and batch distilled in a rectification column (length 2.70 m, inner diameter 40 mm, packed with 1 / 4 inch Teflon® cylinder and a 10 L bottom reboiler).

[0054] The distillation of the hydrofluoroether was carried out under reduced pressure at approximately 81 °C at 80 mbar A (head reflux ratio 10:1).

[0055] The obtained hydrofluoroether mixture was 8060 g and was found to contain 8052 g of the diether HCF2CF2-O-CH2CH2-O-CF2CF2H and 8 g of the monoether HCF2CF2-O-CH2CH2-OH (0.1% by weight of the diether). The yield of the whole process based on the addition amount of ethylene glycol was 86%.

[0056] Comparing the purity and yield of the method of the present invention with those of the prior art, it is clear that the method of the present invention provides a higher yield and higher purity of the obtained hydrofluoroether.

[0057] While within the scope of the following claims, possible modifications and / or additional forms to the embodiments disclosed and exemplified above may be made by those skilled in the art.

Claims

1. Equation (I): CFHX-CF ２ -O-R-O-CF ２ -CFHX (I) One or more compounds of Formula (II): CFHX-CF ２ -O-R-OH (II) one or more compounds (In the formula, - In formulas (I) and (II), R is independently selected from C2-C10 divalent linear or branched alkyl groups, which optionally contain an oxygen heteroatom involved in a ring, aromatic ring, and / or ether bond. - X is selected from halogen, H, and Rf, and Rf is, -- A C1-C8 fully or partially fluorinated linear or branched alkyl group, optionally containing a ring, or -- Fully or partially fluorinated alkoxys of C1-C3 Selected from, the two examples of X in formula (I) are either the same or different, preferably the same. - The amount of one or more compounds of formula (II) is 0.002 to 5% by weight of one or more compounds of formula (I). A liquid composition containing the following:

2. R is, -CH ２ -CH ２ - -CH ２ -CH ２ -CH ２ - -CH ２ -CH ２ -O-CH ２ -CH ２ - -CH ２ -CH ２ -O-CH ２ -CH ２ -O-CH ２ -CH ２ - -CH ２ -CH ２ -CH ２ -O-CH ２ -CH ２ -CH ２ - -CH ２ -CH ２ -CH ２ -O-CH ２ -CH ２ -CH ２ -O-CH ２ -CH ２ -CH ２ - A composition according to claim 1, selected from the following.

3. X represents halogen, H and R ｆ Selected from, R ｆ The composition according to claim 1, wherein is selected from C1-C8 fully or partially fluorinated linear or branched alkyl groups or C1-C3 fully or partially fluorinated alkoxy groups, which optionally contain a ring.

4. R is -CH ２ -CH ２ The composition according to claim 1, wherein X is F.

5. The composition according to claim 1, wherein the amount of one or more compounds of formula (II) is 0.005 to 3% by weight, preferably 0.01 to 2% by weight, and more preferably 0.05 to 1% by weight, of the total amount of one or more compounds of formula (I).

6. The composition according to claim 1, wherein the total amount of the compounds according to formulas (I) and (II) is at least 50% by weight, more preferably at least 70% by weight, even more preferably at least 85% by weight, and most preferably at least 90% by weight, based on the total weight of the composition.

7. A method for producing the composition according to any one of claims 1 to 6, A) One or more polar aprotic organic solvents having a boiling point measured at atmospheric pressure, between 60 and 170°C, preferably between 70 and 90°C, and a general formula: HO-R-OH (III) (In the formula, R- is optionally selected from divalent linear or branched alkyl groups of C2 to C10 that include an O heteroatom involved in a ring, aromatic ring, and / or ether bond.) To provide a mixture comprising one or more bifunctional alcohols having the following properties: B): The above and one or more dihydric alcohols, general formula ..#.. ２ (=) (In the formula, - X is selected from halogen, H, and Rf, and Rf is, -- A C1-C8 fully or partially fluorinated linear or branched alkyl group, optionally containing a ring, or -- Fully or partially fluorinated alkoxys of C1-C3 (Selected from) To provide a reaction mixture containing one or more hydrofluoroethers by reacting one or more fluorinated olefins having a basic catalyst in the presence of a basic catalyst. A method that includes this.

8. The method according to claim 7, wherein the fluorinated olefin is TFE.

9. The method according to claim 7, wherein one or more compounds of formula (III) are selected from dihydric alcohols, preferably ethylene glycol.

10. The method according to claim 7, wherein the one or more polar aprotic organic solvents are acetonitrile.

11. The method according to claim 7, comprising an additional step C in which the hydrofluoroether is preferably extracted directly from the reaction mixture by distillation.

12. D) A step of completely evaporating the reaction mixture and then re-condensing it in liquid form as a purified reaction mixture. E) A step of separating the purified hydrofluoroether from the purified reaction mixture by distillation. The method according to claim 7, further comprising:

13. F) A step of mixing the reaction mixture with water, stirring the mixture to extract water-soluble impurities from the reaction mixture, and separating the purified reaction mixture as a water-immiscible phase. G) A step of separating the purified hydrofluoroether from the purified reaction mixture by distillation. The method according to claim 7, further comprising: