KR20080110203A - Synthesis of hydrofluoroethers using ionic liquids - Google Patents

Abstract

A hydrofluoroether compound is provided to improve the conversion ratio and yield of the alcohol compounds by reacting it for short time. A hydrofluoroether compound is prepared by reacting an alcohol compound with a hydrofluoroolefin compound and using the ionic liquid as a reaction catalyst and solvent. The alcohol compound is selected from C1 ~ 8 alcohol, phenol, hydrofluoro phenol containing the fluorine atoms of 1-5, and C1 - 8 hydrofluoro alcohol containing the fluorine atoms of 1-15. The hydrofluoroolefin compound is selected from the C 2-4 olefin compounds containing the fluorine atoms of 1-8.

Description

Synthesis of hydrofluoroethers using ionic liquids

The present invention relates to a method for producing a fluorine-containing ether compound using an ionic liquid, and more particularly, an ion simultaneously acting as a catalyst and a solvent in the reaction for producing a fluorine-containing compound by reacting an alcohol compound with a fluorine-olefin compound. It relates to a process for producing a fluorine-containing compound at milder conditions and higher yields by using an aqueous liquid.

The fact that Freon gases (CFCs) and second-generation chlorofluorocarbons (CFCs), the hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs), directly affect environmental problems such as ozone layer destruction and global warming After the Montreal Protocol, which has been identified and regulated globally for its production and use, industry and academia have been looking for ways to minimize environmental impacts while using existing materials, while also reducing ozone depletion and global warming impacts. Research is also being done on very low third generation CFC materials.

Hydrogen fluoride ethers (HFEs) are compounds containing alkyl groups consisting of fluorine, hydrogen, and carbon with oxygen as the center. There is no chlorine (Cl) in the molecule, so there is no risk of ozone depletion and global warming potential. It is also significantly smaller than conventional CFC or HFC materials. In addition, it has similar properties to CFCs, but has a lower surface tension, which is good for cleaning complex parts and is less toxic and does not cause smog generation due to photoreaction in the air and thus is not classified as a volatile organic compound (VOC). Due to these excellent properties, HFEs are emerging as 'next generation CFC substitutes' that can act as CFC substitutes after HFC.

Known methods for producing a fluorine-containing ether compound are mainly carried out by reacting a fluorine-containing alcohol compound and a fluorine-containing olefin compound in the presence of a catalyst.

As an example, Japanese Patent Application Laid-Open No. 2005-047856 discloses a technique for producing a fluorine-containing compound by reacting a fluorine-containing alcohol compound with hexafluoropropylene (HPF) using Pd (PPh ₃ ) ₃ as a non-basic catalyst. It explains. However, this method has a disadvantage in that an expensive palladium-based catalyst is used, and the yield is very low at 30% even at a high reaction temperature of 150 ° C. and a long reaction time of 72 hours.

Japanese Laid-Open Patent Publication No. 2002-201152 discloses a method for synthesizing a high purity fluorine-containing compound by reacting an alcohol compound with a fluorine-olefin compound in the presence of a basic compound using water as a solvent. However, this method uses a strong base of potassium hydroxide (KOH), which is limited to commercialization due to device corrosion problems and long reaction time due to its use, and removes water contained in the produced fluorine-containing ether compound. The disadvantage is that it must be seen.

In addition, US Patent No. 5,994,599 describes a method for synthesizing a fluorine-containing ether compound using SbF ₅ as a catalyst, in which case there is a limitation in mass production due to the toxicity and corrosiveness of SbF ₅ .

In addition, US Patent No. 3,291,844 describes a method for preparing a fluorine-containing compound using KF as a catalyst. This patent has the disadvantage of using an excessive amount of catalyst and a long-term reaction of 15 to 200 hours, which makes it difficult to industrialize in reality.

As described above, although a technique of using an alkoxide, hydroxide or halide of an alkali metal as a catalyst for preparing a fluorine-containing compound is known, the reaction temperature is high, the reaction time is long, and the target fluorine-containing In addition to improving the yield of the ether compound, there is a problem in that the resulting fluorinated ether compound is converted to a fluorinated olefin ether compound by dehydrogenation by a catalyst.

Therefore, it has been pointed out that the conventional method for preparing the fluorine-containing ether compound is difficult to efficiently separate the fluorine-containing compound from the product due to low conversion, yield, and side reactions, so that there is room for improvement in commercialization.

Accordingly, the present inventors have tried to develop a method for more efficiently preparing a fluorine-containing compound having a high industrial value as a next-generation CFC substitute. As a result, in carrying out the general process of synthesizing the fluorine-containing compound by reacting the alcohol compound with the fluorine-containing olefin compound, using the ionic liquid as a catalyst and a solvent, it is possible to synthesize the fluorine-containing compound in a high yield within a short time. Instead, the present invention has been completed by knowing that the process of separating the product from the ionic liquid becomes very simple.

Accordingly, an object of the present invention is to provide a method for producing a fluorine-containing compound in a high yield in a short time.

The present invention is characterized in that an ionic liquid is used as the reaction catalyst and the solvent in the method for producing a fluorine-containing compound by reacting an alcohol compound with a fluorine-containing olefin compound.

Referring to the present invention in more detail as follows.

The alcohol compound used as a raw material in the production method according to the present invention is an alcohol having 1 to 8 carbon atoms, phenol, a fluorine-containing phenol containing 1 to 5 fluorine atoms, and 1 to 8 carbon atoms containing 1 to 15 fluorine atoms. It may be selected from fluorine-containing alcohol. Specific examples of such an alcohol compound include CH ₃ OH, CH ₃ CH ₂ OH, CH ₃ CH ₂ CH ₂ OH, (CH ₃ ) ₂ CHOH, CH ₃ (CH ₂ ) ₃ OH, (CH ₃ ) ₂ CHCH ₂ Alcohols such as OH, (CH ₃ ) ₃ CCH ₂ OH, CH ₃ (CH ₂ ) ₄ OH, CH ₃ (CH ₂ ) ₅ OH, CH ₃ (CH ₂ ) ₆ OH, CH ₃ (CH ₂ ) ₇ OH; phenol; Fluorine-containing phenols such as C ₆ FH ₄ OH, C ₆ F ₂ H ₃ OH, C ₆ F ₃ H ₂ OH, and C ₆ F ₄ HOH; CF ₃ OH, CF ₃ CF ₂ OH, CF ₃ CF ₂ CH ₂ OH, CF ₃ (CF ₂ ) ₂ CH ₂ OH, CF ₃ (CF ₂ ) ₃ CH ₂ OH, CF ₃ (CF ₂ ) ₄ CH ₂ OH And fluorine-containing alcohols such as CF ₃ (CF ₂ ) ₅ CH ₂ OH and CF ₃ (CF ₂ ) ₆ CH ₂ OH.

As another raw material, the fluorine-containing olefin compound may be selected from olefin compounds having 2 to 4 carbon atoms containing 1 to 8 fluorine atoms. Specific examples of such fluorine-containing olefin compounds include CHF = CH ₂ , CHF = CHF, CF ₂ = CH ₂ , CF ₂ = CHF, CF ₂ = CF ₂ , CHF = CFCF ₃ , CF ₂ = CFCF ₃ , CF ₂ = CFCF ₂ CF ₃ and the like can be included.

In the reaction of the alcohol compound with the fluorine-containing compound, it is preferable to use an excess of the fluorine-containing compound. That is, the fluorine-containing olefin compound is used in the range of 1 to 15 mole times, more preferably in the range of 1 to 10 mole times based on 1 mole of the alcohol compound. When the amount of the fluorine-containing olefin compound is less than 1 mole times, the unreacted alcohol compound remains poor in conversion rate, and when the excess is used in excess of 15 mole times, there is a disadvantage that the excess fluorine-containing olefin compound has to be recovered.

The present invention is characterized by the use of ionic liquids as catalysts and solvents.

Ionic liquids are ionic liquids composed of organic cations and anions. They exist as liquids at room temperature, have no common vapor pressure, and have high solubility in ions. [P. Wasserscheid, T. Welton, "Ionic liquids in Synthesis", Wiley-VCH, Weinheim, 2003] may contain the anion is ^{F -, Cl -, Br -} , OAc -, N (CN) 2 -, OAc -, NO 2 -, _{^{NO 3 -, BF 4 -,}} PF 6 -, AlCl 4 -, Al 2 Cl 7 -, AcO -, SO 4 2-, CF 3 SO 2 O -, (CF 3 SO 2) 2 N -, CF 3 CO ^_2, CH ₃ CH (OH) CO ₂ ^- and the like. In addition, since the ionic liquid can control the physicochemical properties by changing the structure of the cation and anion constituting the ionic liquid, it is also important to select and use an ionic liquid having a suitable structure according to the purpose of use. .

According to the research of the present inventors, an ionic liquid applied to the reaction of an alcohol compound and a fluorine-containing olefin compound is selected from tetraalkylammonium, dialkylimidazolium, alkylpyridinium, dialkylpyrrolidinium, and dialkyl morpholinium. nitrogen-containing organic ^{cations, F -, Cl -, Br} -, OAc -, N (CN) 2 -, OAc -, MeSO ₃ ^-, and NO ₂ ^- is preferred to use an ionic liquid consisting of an anion selected from the group consisting of. At this time, alkyl is alkyl having 1 to 8 carbon atoms, preferably alkyl having 1 to 6 carbon atoms. Specific examples of the nitrogen-containing organic cation include tetrabutylammonium, 1-methyl-3-butylimidazolium, 1-methyl-3-hexylimidazolium, 1-methyl-3-octylimidazolium, 1 -n-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-butylpyridinium, 1-ethyl-3-propylpyrrolidinium, 1,1-dipentylmorpholinium May be included.

The ionic liquid proposed by the present invention may be characterized by the selection of anions which are bound to nitrogen-containing organic cations, where the anion has a weak basicity or the ability to hydrogen bond with the fluorinated olefin compound and alcohol. The hydroalkoxylation reaction between compounds can be further promoted. In addition, the ionic liquid proposed by the present invention does not mix with the fluorine-containing ether compound, which is a desired product, so that after the reaction, the product can be easily separated from the mixture using a liquid / liquid separation method or a simple distillation method. There is this. In addition, the ionic liquid proposed by the present invention not only acts as a reaction solvent but also acts as a catalyst to promote the reaction, and thus, even in a low temperature range around 25 ° C, for a short time of several seconds to several tens of minutes. The reaction also provides an improved effect of greatly improving the conversion of the alcohol compound and the yield of the fluorine ether compound.

In carrying out the preparation method of the present invention, the ionic liquid may be used in a small amount in a catalytic amount, but when used as a catalyst and a solvent, it is preferable to use a relatively excessive amount. That is, the ionic liquid is suitably in the range of 1 to 500% by weight, preferably 50 to 500% by weight, based on the weight of the alcohol compound used as the raw material. If the amount of the ionic liquid is too small, the catalytic effect is weak and the reaction rate is too slow. If the excess ionic liquid is used in excess of 500% by weight, the reaction rate is not increased or the selectivity is not improved. Can not do it.

Synthesis reaction of the fluorine-containing compound in the presence of the ionic liquid can be carried out using a high pressure reactor equipped with a stirrer.

The reaction temperature is to maintain the range 0 ~ 100 ℃, preferably to maintain the range of 10 ~ 90 ℃, especially the reaction is carried out smoothly even at a temperature around room temperature (25 ℃). However, when the reaction temperature is lower than 0 ° C, the reaction rate is slow, and when the reaction temperature is maintained above 100 ° C to maintain a high temperature there is a problem that the resulting fluorinated olefin compound is polymerized.

If necessary, a reaction solvent may be further used while using a catalytic amount of the ionic liquid. As a solvent that can be used in the production method of the present invention, a conventional organic solvent can be used, and considering the reactivity with the fluorine-containing alcohol compound, it is preferable to use an aprotic solvent. As such an aprotic solvent, nitriles of acetonitrile, ketones of acetone, amides of dimethylformamide, aromatic hydrocarbons of toluene, aromatic halogenated hydrocarbons of chlorobenzene, and aliphatic halogenated hydrocarbons of dichloromethane are used. Can be. The amount of the solvent used is 0.5 to 20 times by weight, preferably 1 to 10 times by weight, based on the weight of the alcohol compound.

 The present invention as described above will be described in more detail based on the following examples, but the present invention is not limited by the following examples.

Example 1

5 g (50 mmol) of 2,2,2-trifluoroethanol and 5 g of 1-methyl-3-butylimidazolium chloride were charged to a 100 mL high pressure reactor, followed by 7.5 g (100 mmol) of hexafluoropropylene. Injected into the reactor. After reaction at room temperature (25 ° C.) for 30 minutes, the reactor is opened and the product is divided into an upper layer mainly containing the product and a lower layer containing an ionic liquid. As a result of analyzing the product by GC and GC-Mass, it was confirmed that the product CF ₃ CH ₂ OCF ₂ CHFCF ₃ was synthesized in a yield of 94% .The product layer was separated and analyzed by NMR to detect ionic liquid. Did.

In addition, the conversion rate of the alcohol compound and the yield of the fluorine-containing compound were calculated by the following formulas (1) and (2), respectively.

Examples 2-9

The fluorine-containing ether compound was synthesized while changing only the type of alcohol under the same conditions as in Example 1, and the results are shown in Table 1 below.

division Type of alcohol Alcohol conversion rate (%) Yield of fluorine-containing ether (%) Example 1 CF ₃ CH ₂ OH 100 94.0 Example 2 CH ₃ OH 100 93.4 Example 3 CH ₃ CH ₂ CH ₂ OH 100 91.7 Example 4 CF ₃ CH ₂ CH ₂ OH 100 96.0 Example 5 CF ₃ CF ₂ CH ₂ OH 100 94.4 Example 6 CF ₃ CF ₂ CF ₂ CH ₂ OH 100 96.0 Example 7 CH ₃ (CH ₂ ) ₇ OH 100 92.8 Example 8 phenol 100 90.7 Example 9 Pentafluorophenol 100 91.2

Examples 10-14

Under the same conditions as in Example 1, the fluorine-containing ether compound was synthesized while changing the type and amount of fluorine-containing olefin, and the results are shown in Table 2 below.

division Type of olefin Molar ratio of alcohol / olefin Alcohol conversion rate (%) Yield of fluorine-containing ether (%) Example 1 CF ₃ CF = CF ₂ 1/2 100 94.0 Example 10 CH ₂ = CHF 1/10 100 98.2 Example 11 CH ₂ = CF ₂ 1/5 100 90.6 Example 12 CHF = CF ₂ 1/2 100 92.4 Example 13 CF ₂ = CF ₂ 1/1 100 93.1 Example 14 CF ₃ CF ₂ CF = CF ₂ 1/10 100 91.7

Examples 15-21

The fluorine-containing ether compound was synthesized while changing the type of the ionic liquid under the same conditions as in Example 1, and the results are shown in Table 3 below.

division Type of ionic liquid Alcohol conversion rate (%) Yield of fluorine-containing ether (%) Cation Negative ion Example 1  1-methyl-3-butylimidazolium Cl 100 94.0 Example 15  1-methyl-3-hexylimidazolium Br 84.0 81.6 Example 16  1-methyl-3-octylimidazolium F 92.7 88.4 Example 17  Tetrabutylammonium N (CN) ₂ 96.3 92.0 Example 18  Tetrabutylammonium Oac 97.5 92.9 Example 19  1-ethyl-3-propylpyrrolidinium NO ₂ 88.6 84.1 Example 20  1-ethyl-3-propylpyrrolidinium MeSO ₃ 85.4 76.5 Example 21  1,1-dipentylmorpholinium Oac 94.5 89.3 Example 22  1,1-dipentylmorpholinium N (CN) ₂ 90.1 85.4

Examples 22-26

The fluorine-containing ether compound was synthesized while varying the amount of the ionic liquid under the same conditions as in Example 1, and the results are shown in Table 4 below.

division Ionic liquid usage (% by weight) Alcohol conversion rate (%) Yield of fluorine-containing ether (%) Example 1 100 100 94.0 Example 22 10 86.0 82.5 Example 23 50 100 95.1 Example 24 200 100 96.4 Example 25 300 100 96.8 Example 26 500 100 98.0

Examples 27-30

Fluorine-containing ether compounds were synthesized by changing the reaction temperature under the same conditions as in Example 1, and the results are shown in Table 5 below.

division Reaction temperature (℃) % Conversion of alcohol Yield of fluorine-containing ether (%) Example 1 25 100 94.0 Example 27 0 62.0 61.3 Example 28 50 100 93.1 Example 29 80 100 91.8 Example 30 100 100 90.6

Example 31

The reaction was performed under the same conditions as in Example 1, and when the reaction was completed, the reaction solution was separated into a liquid / liquid layer, and the lower layer in which the ionic liquid was present was reused. Table 6 shows the conversion and the yield by the number of reuse of the ionic liquid.

division Number of catalyst reuses (times) % Conversion of alcohol Yield of fluorine-containing ether (%) Example 1 0 100 94.0 Example 31 One 100 95.4 Example 32 2 100 97.6 Example 33 3 100 96.1 Example 34 4 100 96.5 Example 35 5 100 94.8

Comparative Examples 1 to 3

In this comparative example, the fluorine-containing compound was synthesized by a conventional method using a KF, KOH or KOCH ₃ catalyst instead of an ionic liquid as a catalyst.

That is, 1 g of KF, KOH, or KOCH _{3 was} respectively filled in the center of the reactor made of stainless, and the empty part was filled with 2 mm diameter glass beads. In addition, a 2,2,2-trifluoroethanol (CF ₃ CH ₂ OH) solution dissolved in 1 mol / L in acetonitrile was used at a rate of 1 mL / min by using a high pressure pump (HPLC pump). Hexafluoropropylene (CF ₂ = CFCF ₃ ) was injected into the reactor at a rate of 44.8 mL / min using a mass flow controller (MFC). The product exiting the bottom of the reactor was analyzed by GC and GC-Mass, the results are shown in Table 7 below.

division Type of catalyst Reaction time Reaction temperature Alcohol conversion rate (%) Yield of product (%) Fluorinated ether Fluorinated olefin ethers Example 1 1-methyl-3-butylimidazolium 30 minutes 25 ℃ 100 96.0 4.0 Comparative Example 1 KF 30 minutes 25 ℃ 100 52.7 22.7 Comparative Example 2 KOH 30 minutes 25 ℃ 100 62.4 28.5 Comparative Example 3 KOCH ₃ 30 minutes 25 ℃ 100 58.2 24.6

According to the results of Table 1 to Table 6, it can be seen that the reaction to which the ionic liquid is applied according to the present invention has a high conversion rate of the alcohol compound and a high yield of the fluorine-containing compound. According to the results of Table 6, the ionic liquid used in the present invention can be easily separated and recovered by a simple purification method such as liquid / liquid separation, and excellent conversion and yield can be obtained even if it is used five times or more.

In addition, according to the results of Table 7, in Comparative Examples 1 to 3 using an alkali metal halide, hydroxide or alkoxide as a catalyst according to the conventional manufacturing method, the conversion rate of the alcohol compound was high, but the reaction time was short and the fluorine-containing olefin as a side reaction product. As ether compounds are produced, it can be seen that the yield of the desired fluorine-containing compound is low.

As described above, the present invention is characterized in that an ionic liquid is used as a catalyst and a solvent in a conventional reaction of preparing an fluorine-containing compound by reacting an alcohol compound with a fluorine-containing olefin compound. As a result, the production method according to the present invention has a significant effect of greatly improving the conversion of alcohol compounds and the yield of fluorine-containing compounds by reacting at a low reaction temperature around room temperature for a few seconds to several tens of minutes. In addition, in the conventional manufacturing method, the produced fluorinated ether compound is dehydrogenated to produce a side reaction product of the fluorine-containing olefin ether. The improved effect of suppressing side reactions and significantly reducing the yield of the side reactants of the fluorine-containing olefin ether is also obtained. In addition, the ionic liquid used as the catalyst and the solvent of the present invention can be easily separated by a simple purification method such as liquid / liquid separation or simple distillation from the reaction product, and thus can be reused repeatedly to obtain excellent economic efficiency.

Therefore, the preparation method of the present invention is particularly useful as an industrial mass production method of a fluorine-containing compound having a high industrial value as a next-generation CFC substitute.

Claims (8)

In the method for producing an fluorine-containing compound by reacting an alcohol compound and a fluorine-containing olefin compound, A method for producing a fluorine-containing compound, characterized in that an ionic liquid is used as the reaction catalyst and the solvent. The method of claim 1, The alcohol compound is prepared from an alcohol having 1 to 8 carbon atoms, phenol, a fluorine-containing phenol containing 1 to 5 fluorine atoms, and a fluorine-containing alcohol having 1 to 8 carbon atoms containing 1 to 15 fluorine atoms. Way. The method of claim 1, The fluorine-containing olefin compound is selected from olefin compounds having 2 to 4 carbon atoms containing 1 to 8 fluorine atoms. The method according to claim 1 or 3, The amount of the fluorine-containing olefin compound is a production method, characterized in that 1 to 10 mole times range based on 1 mole of alcohol compound. The method of claim 1, The ionic liquid is nitrogen-containing organic cation selected from tetraalkylammonium, dialkylimidazolium, alkylpyridinium, dialkylpyrrolidinium, and dialkyl morpholinium, wherein alkyl is alkyl having 1 to 8 carbon atoms, ^{F -, Cl -, Br -} , OAc -, N (CN) 2 -, OAc -, MeSO ₃ ^-, and NO ₂ ^- production process, characterized in that the ionic liquid consisting of an anion selected from the group consisting of. The method of claim 5, The cations constituting the ionic liquid are tetrabutylammonium, 1-methyl-3-butylimidazolium, 1-methyl-3-hexylimidazolium, 1-methyl-3-octylimidazolium, 1-butyl- 3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-butylpyridinium, 1-ethyl-3-propylpyrrolidinium, and 1,1-dipentylmorpholinium, wherein the anion is ^{F -, Cl -, Br -} , OAc -, N (CN) 2 -, OAc -, MeSO ₃ ^-, and NO ₂ ^- production process, characterized in that is selected from the. The method according to claim 1, 5 or 6, The amount of the ionic liquid is a manufacturing method, characterized in that 10 to 500% by weight based on the weight of the alcohol compound. The method of claim 1, Said reaction temperature is 0-100 degreeC, The manufacturing method characterized by the above-mentioned.