JP2010001272A - Method of preparing ethyl iodides substituted with fluorine-containing alkyl - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of industrially preparing ethyl halides substituted with a fluorine-containing alkyl using an industrially available raw material, and a method of industrially preparing ethyl iodides substituted with a fluorine-containing alkyl useful as an agent for introducing a fluorine-containing carbon substituent, using the above ethyl halides substituted with a fluorine-containing alkyl as a raw material. <P>SOLUTION: Disclosed are a method of preparing an ethyl halide substituted with a fluorine-containing alkyl characterized by reducing a vinyl halide substituted with a fluorine-containing alkyl in the presence of a catalyst comprising at least one species of metal selected from palladium and rhodium (a reducing step), and a method of preparing an ethyl iodide substituted with a fluorine-containing alkyl by iodizing the compound prepared above (an iodizing step). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluorine-containing alkyl-substituted ethyl halide represented by the general formula [2]

[In the formula, Rf is a linear or branched fluorine-containing alkyl group having 1 to 6 carbon atoms, a general formula C _a H _b F _c- (a: an integer of 1 to 6, b: 0 to (2 X is an integer up to a), c: an integer of (2 × a) −b + 1), and X is a chlorine atom or a bromine atom.] And the fluorine-containing alkyl-substituted ethyl halide The present invention relates to a method for producing fluorine-containing alkyl-substituted ethyl iodides, which are useful as an introducing agent for fluorine-containing carbon substituents.

  Fluorine-containing alkyl-substituted ethyliodos are compounds useful as introducing agents for fluorine-containing carbon substituents, and pharmaceuticals having such sites have been developed (Patent Document 1).

  The raw material fluorine-containing alkyl-substituted ethyl halides can be produced by fluorinating chlorine-containing alkyl-substituted ethyl halides. For example, by fluorination of 1,1,1,3-tetrachloropropane, 1-chloro-3 , 3,3-trifluoropropane is disclosed (formulas (III) to (V) at the bottom of p17 of Patent Document 2). This is an efficient technique with high selectivity, but it is difficult to handle because it uses hydrogen fluoride and an antimony catalyst, and an acid-resistant apparatus is required for production, which is not an industrially excellent method.

  On the other hand, for the reduction of halofluoroolefin, for example, 1,1,1,3,3 is obtained by reducing 2-chloro-1,1,3,3,3-pentafluoropropene with hydrogen in the presence of a catalyst. -It is disclosed that pentafluoropropane and / or 1,1,3,3,3-pentafluoropropene is produced ("0050" of Patent Document 3).

Furthermore, “0015” of Patent Document 4 suggests that chlorine atoms are hydrogenated when hydrogen is allowed to act on a chlorohydrofluoroalkane having a trifluoromethyl group in the presence of a catalyst (Patent Document 4).
International Publication No. 2008/34735 Pamphlet JP 52-46004 A Japanese Patent Laid-Open No. 7-069943 JP-A-6-256235

  As described above, although there is a prior example related to the reduction reaction of halofluoroolefin, “in the reduction of a fluorine-containing alkyl-substituted olefin having a chlorine atom in the double bond, the olefinic double bond is selectively selected while the chlorine atom remains. No case has been reported.

In the above Patent Document 3, too, in the reduction of 2-chloro-1,1,3,3,3-pentafluoropropene, if the conditions for reduction are too strong, 1,1,1,3,3-penta is caused by overreduction. Even when fluoropropane is produced and the conditions are adjusted, the chlorine atom is eliminated and only 1,1,3,3,3-pentafluoropropene is produced, and CF ₃ —CH ₂ containing the chlorine atom is present. Formation of —CH ₂ —Cl is not observed.

  Since fluorine-containing substituted alkyl vinyl halides are commercially available, the olefinic double bond of fluorine-containing substituted alkyl vinyl halides is reduced, while a halogen atom is present, and the desired general formula [2] There has been a demand for a method for producing a fluorine-containing substituted alkylethyl halide represented by the formula:

  That is, the present invention provides an industrial production method of fluorine-containing alkyl-substituted ethyl halides using commercially available raw materials, and uses fluorine-containing alkyl-substituted ethyl halides as raw materials for fluorine-containing carbon substituents. It is an object of the present invention to provide a method for industrially producing fluorine-containing alkyl-substituted ethyl iodides useful as an introducing agent.

  In view of the problems of the prior art, the present inventors have prepared a method for producing fluorine-containing alkyl-substituted ethyl halides suitable for production on an industrial scale, and further, fluorine-containing materials using the fluorine-containing alkyl-substituted ethyl halides as raw materials. In order to establish a method for producing alkyl-substituted ethyl iodides, intensive studies were conducted.

  As a result, fluorine-containing alkyl-substituted vinyl halides represented by the general formula [1] that can be obtained at low cost

[Rf and X in the general formula [1] have the same meaning as described above. Is reduced with hydrogen under specific conditions to give fluorine-containing alkyl-substituted ethyl halides represented by the general formula [2]

Found that you get.

  Furthermore, as a second step, the general formula [2] produced by the above production method [where Rf and X in the formula have the same meaning as in the general formula [1]. In the general formula [3] [general formula [3], the target Rf has the same meaning as the general formula [2] by iodination of the fluorine-containing alkyl-substituted ethyl halides represented by formula (I). The present inventors have found that fluorine-containing alkyl-substituted ethyl iodides represented by the following general formulas can be obtained.

  As described above, in a reaction in which a fluorine-containing alkyl-substituted vinyl halide is reduced with hydrogen in the presence of a catalyst, the corresponding fluorine-containing alkyl-substituted halide is produced by selectively reducing only the double bond while leaving the chlorine atom present. This is recognized by those skilled in the art as being very difficult, and has been achieved for the first time by the present invention.

  That is, the present invention includes [Invention 1] to [Invention 8] and provides a novel method for producing fluorine-containing alkyl-substituted ethyliodos.

  “Invention 1” A fluorine-containing alkyl-substituted vinyl halide represented by the general formula [1]

[Wherein Rf is a linear or branched fluorine-containing alkyl group having 1 to 6 carbon atoms, and is represented by the general formula CaHbFc- (a: an integer from 1 to 6, b: 0 to (2 × a)) C: an integer of (2 × a) −b + 1), and X is a chlorine atom or bromine. ] Is reduced with hydrogen in the presence of a catalyst containing at least one metal selected from palladium or rhodium, and the method for producing fluorine-containing alkyl-substituted ethyl halides represented by the general formula [2].

[Wherein, Rf and X are the same as those in the general formula [1]. ]
“Invention 2” The catalyst is a catalyst in which a metal is supported on a carrier, and the carrier is at least one selected from alumina, activated carbon, fluorinated aluminum, diatomaceous earth, febroin, and silica gel. The method for producing a fluorine-containing alkyl-substituted ethyl halide according to the first aspect.

  [Invention 3] The process for producing a fluorinated alkyl-substituted ethyl halide according to any one of Inventions 1 to 2, wherein the ratio of the metal to the carrier in the catalyst is 0.1 to 5% by weight.

  [Invention 4] The method for producing a fluorine-containing alkyl-substituted ethyl halide according to any one of Inventions 1 to 3, wherein the hydrogen pressure is from atmospheric pressure to 15 MPa.

  [Invention 5] The process for producing an alkyl-substituted ethyl halide according to any one of Inventions 1 to 4, wherein the fluorine-containing alkyl group is a trifluoromethyl group.

  [Invention 6] The process for producing a fluorinated alkyl-substituted ethyl halide according to any one of Inventions 1 to 5, wherein X in the general formula [1] or the general formula [2] is a chlorine atom .

  [Invention 8] It is represented by the general formula [3], characterized in that the fluorine-containing alkyl-substituted ethyl halides represented by the general formula [2] obtained by any method of the inventions 1 to 7 are iodinated. For producing fluorine-containing alkyl-substituted ethyl iodides.

[Wherein Rf is the same as in general formula [2]. ]

  According to the present invention, fluorine-containing alkyl-substituted ethyl halides can be produced using industrially available raw materials, and fluorine-containing alkyl-substituted ethyl iodides can be efficiently produced from the fluorine-containing alkyl-substituted ethyl halides.

  The production method of the present invention comprises a step of reducing fluorine-containing alkyl-substituted vinyl halides to fluorine-containing alkyl-substituted ethyl halides (first step: reduction step), and fluorine-containing alkyl-substituted ethyl halides in the form of fluorine-containing alkyl substitution. The present invention provides a step of iodination into ethyl iodides (second step: iodination step).

[Wherein Rf is a linear or branched fluorine-containing alkyl group having 1 to 6 carbon atoms, and is represented by the general formula C _a H _b F _c- (a: an integer of 1 to 6, b: 0 to (2 × an integer up to a), c: an integer of (2 × a) −b + 1), and X is a chlorine atom or a bromine atom. ]
However, in the reduction of fluorinated alkyl-substituted vinyl halides, side reactions easily proceed to produce fluorinated alkyl-substituted ethyl. The following path A and path B are possible as possible side reactions.

[In general formula [1] and general formula [2], Rf and X have the same meaning as in the previous term. ]
In pass A, the produced fluorine-containing alkyl-substituted ethyl halides (general formula [2]) are hydrogenated under reducing conditions to produce fluorine-containing alkyl-substituted ethyl compounds (formula [3]).

  In pass B, after the chlorine atom is eliminated and the corresponding fluorine-containing alkyl-substituted vinyl (formula [4]) is produced, the reducing agent acts to produce fluorine-containing alkyl-substituted ethyl. The chlorine atom is easily eliminated because the fluorine-containing alkyl is substituted with a double bond, and the electron-withdrawing group is bonded to the β-position of vinyl, thereby oxidative addition to the carbon-chlorine bond. It is thought that is easy to progress. In pass B, when the reduction reaction is fast, the formation of fluorine-containing alkyl-substituted vinyls that may be considered as intermediates may not be observed.

Therefore, as in the present invention, the corresponding fluorine-containing alkyl-substituted ethyl halides are produced by selectively reducing only double bonds while leaving chlorine atoms in place, and the production of by-product fluorine-containing alkyl-substituted ethyls is also produced. In order to suppress this, it was necessary to study the reaction conditions including the study of the catalyst. Hereinafter, each process is demonstrated in detail.

[About the first step (reduction step)]
[About raw materials]
The fluorine-containing alkyl substituent Rf of the fluorine-containing alkyl-substituted vinyl halides represented by the general formula [1] targeted by the reductive hydrogenation reaction of the present invention is a linear or branched group having 1 to 6 carbon atoms. A fluorine alkyl group having the general formula C _a H _b F _c — (a: an integer of 1 to 6, b: an integer from 0 to (2 × a), c: an integer of (2 × a) −b + 1) And X is a chlorine atom or a bromine atom. Examples of these fluorine-containing alkyl substituents include a methyl group containing a fluorine atom, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a hexyl group. The number and position of fluorine atoms contained in these fluoroalkyl groups are not limited. Among these, preferred fluorine-containing alkyl substituents are 2,2-difluoroethyl, 2,2,2-trifluoroethyl, 1,2,2,2-tetrafluoroethyl, 3,3,3-trifluoropropyl. Perfluoroalkyl groups such as 2,2,3,3,3-pentafluoropropyl and trifluoromethyl groups, perfluoroethyl groups, n-perfluoropropyl groups, n-perfluorobutyl groups, and the like. An alkyl group is more preferable, and a trifluoromethyl group is particularly preferable.
A trifluoromethyl group is particularly preferred.

  The halogen substituent X of the fluorinated alkyl-substituted vinyl halide represented by the general formula [1] targeted by this reduction step is a chlorine atom or a bromine atom, and an easily available chlorine atom is preferable.

  These fluorine-containing alkyl-substituted vinyl halides represented by the general formula [1] can be produced by fluorinating a corresponding chlorine-containing alkyl-substituted ethyl dihalide, for example, 1,1,1,3,3-pentachloropropane. 1-Chloro-3,3,3-trifluoropropene can be produced by fluorination without a catalyst (Japanese Patent Laid-Open No. 10-067693).

  The fluorine-containing alkyl substituents Rf and X of the fluorine-containing alkyl-substituted ethyl halides represented by the general formula [2] targeted by this reduction step are the same as those in the general formula [1].

  The reduction process of the present invention can be carried out in batch-type and flow-type reactors. The batch reaction conditions will be described below, but this does not preclude changes in reaction conditions that can be easily adjusted by those skilled in the art.

[About catalyst]
In this reduction process, the catalyst contains at least one metal selected from palladium and rhodium. It is also possible to use an alloy of the above two metals. By using at least one catalyst selected from palladium or rhodium, the side reaction proceeds but a fluorine-containing substituted alkylethyl halide represented by the general formula [2] is generated.

  When the above metal is used as a catalyst, a poisoned metal can be used for the purpose of suppressing side reactions and increasing the reaction selectivity. The poisoning metal is preferably a kind of metal selected from sodium, potassium, barium, titanium, zirconium, vanadium, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, zinc, tin, and bismuth or a salt thereof.

  Examples of the form of the catalyst containing the metal include fine particles, a complex with a ligand, and a supported catalyst supported on a carrier. The carrier in the case of carrying on the carrier is alumina, zirconium oxide, chromium oxide, titanium oxide, iron oxide, nickel oxide, cobalt oxide, magnesium oxide, metal oxide such as antimony oxide, activated carbon, fluorinated aluminum, diatomaceous earth, febroin, At least one selected from the group consisting of silica gel, calcium sulfate, barium sulfate or lead sulfate can be used, and two or more types can be used in combination. In the metal oxide, a composite metal oxide obtained by combining two or more of the above metal oxides can also be used. Among these, it is preferable to use at least one selected from alumina, activated carbon, fluorinated aluminum, diatomaceous earth, febroin, and silica gel, and alumina and activated carbon are more preferable.

  Although the preparation method of an alumina is not specifically limited, It can prepare by a well-known method. For example, it can be prepared by drying an aluminum hydroxide sol obtained by neutralizing and precipitating a water-soluble aluminum salt with ammonia, and then pulverizing and molding the resulting mass, followed by firing. At this time, a composite metal oxide mainly composed of alumina by using in combination with at least one metal compound selected from the group consisting of zirconium, chromium, titanium, iron, nickel, cobalt, magnesium, zirconium and antimony together with an aluminum compound. A product can also be prepared.

  In the case of using the metal supported on a carrier, the ratio of the metal to the carrier is 0.1% by weight to 5% by weight, and more preferably 0.5% by weight to 2% by weight. The lower the ratio of the metal catalyst relative to the carrier, the more the side reaction of elimination of chlorine atoms can be suppressed. On the other hand, if the amount is 0.1% by weight or less, the dispersion of the catalyst is too dilute, which increases the amount of necessary carrier, which is not economically preferable. From the viewpoint of suppressing side reactions, the lower the ratio of the metal to the carrier, the more advantageous. However, when using such a catalyst, it is necessary to devise measures such as increasing the amount of the supported catalyst in order to increase the reaction efficiency. is there.

  In this reduction reaction, a metal catalyst is supported on a carrier, but a general method can be used. In the case of alumina, an impregnation method or a kneading method can be used, and in the case of activated carbon, an impregnation method or the like can be used. Of course, a commercially available supported catalyst may be used.

  Although it is the usage-amount of the metal catalyst with respect to a board | substrate, 0.00001-2 are preferable and, as for the ratio of the molar equivalent with respect to a substrate, 0.0001-0.01 are more preferable. If it is 0.00001 or less, the reaction is difficult to proceed and a long reaction time is required, which is not preferable. If the molar equivalent ratio exceeds 2, the reaction can be carried out rapidly, but the number of catalysts not involved in the reaction increases, which is not economically preferable.

[About reaction]
The reaction in this reduction step generates the compound represented by the general formula [2] according to the scheme shown in the above path A, and therefore it is necessary to suppress the subsequent hydrogenation in path A and the side reaction in path B.

  In this reduction step, hydrogen is used as a reducing agent. The amount of hydrogen used relative to the substrate is preferably 0.1 to 30, more preferably 0.5 to 5, more preferably 0.8 to 2, in the molar ratio to the substrate. Particularly preferred. If it is less than 0.1, the conversion rate of the reaction is lowered, and unreacted raw materials remain, which is not preferable. On the other hand, if it exceeds 30, the amount of hydrogen not involved in the reaction increases, which is not economically preferable.

  In this reduction step, the reaction proceeds even at normal pressure, but the reaction can also be carried out by injecting hydrogen for the purpose of accelerating the reaction. The reduction reaction easily proceeds by pressurization. In this case, the hydrogen pressure is preferably within 15 MPa from atmospheric pressure, and more preferably from 0.5 MPa to 10 MPa. Making the hydrogen pressure lower than atmospheric pressure is not advantageous for industrialization, and if it exceeds 15 MPa, a reactor that can withstand this is required, which is not preferable for industrialization.

  Although this reduction process proceeds without using any solvent, a solvent can be used for the purpose of increasing the reaction selectivity, reaction rate, operability, catalyst life, and catalyst rotation speed. Alcohol solvents such as methanol, ethanol, propanol and ethylene glycol, nitrile solvents such as acetonitrile and benzonitrile, sulfoxide solvents such as dimethyl sulfoxide, ether solvents such as diethyl ether, diisopropyl ether, dibutyl ether and tetrahydrofuran, methylene chloride And at least one compound selected from halogenated solvents such as chloroform and carbon tetrachloride, aromatic hydrocarbon solvents such as benzene, toluene and xylene, pentane, hexane and heptane.

  When a solvent is used, the effect varies depending on the solvent used. Therefore, the amount of the solvent cannot be uniquely determined, but it is preferably 5 to 1000% by weight, preferably 30% by weight based on the raw material substrate. % To 500% by weight is more preferred. If it is less than 5% by weight, there is no effect to be added, and if it exceeds 1000% by weight, it is not economically preferable.

  Although this reduction process proceeds without using any additive, an additive may be used for the purpose of increasing the reaction selectivity, reaction rate, catalyst life, and catalyst rotation speed. Additives include nitric acid, sulfuric acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid and other mineral acids, acetic acid, carboxylic acid compounds such as trifluoroacetic acid, fluorosulfonic acid, methanesulfonic acid, At least one compound selected from sulfonic acid compounds such as paratoluenesulfonic acid and trifluoromethanesulfonic acid is preferred. The presence of these acidic compounds in the system may inhibit the reaction from further tilting to the acidic side, and the elimination of side reaction hydrogen halide (hydrogen chloride or hydrogen bromide) may be suppressed. Can also be expected.

  Basic compounds such as amine compounds such as ammonia, trimethylamine, triethylamine, tripropylamine, tributylamine, pyridine, 2,6-dimethylpyridine, N, N-dimethylaminopyridine are produced by elimination of hydrogen halides. Since it reacts with (hydrogen chloride or hydrogen bromide) and acts in the direction of promoting side reactions, it is not preferred as an additive.

  When an additive is used, the effect varies depending on the additive used, so the amount of the additive cannot be uniquely determined, but is 0.01% to 100% by weight based on the raw material substrate. Is preferable, and 0.5 to 30% by weight is more preferable. If it is less than 0.01% by weight, there is no effect of addition, and if it exceeds 100% by weight, it is not economically preferable.

[Reaction temperature]
Although there is no special restriction | limiting in the reaction temperature at the time of implementing this reduction | restoration process, Usually, it is -50-100 degreeC, -20-70 degreeC is preferable, and 0 degreeC-50 degreeC is especially preferable. Below −50 ° C., the reaction slows down, and cooling is expensive, which is not desirable. Moreover, when it exceeds 100 degreeC, a side reaction will advance easily and it will become difficult to achieve selective synthesis | combination.

  The reactor for carrying out this reduction step is preferably a reactor made of tetrafluoroethylene resin, chlorotrifluoroethylene resin, vinylidene fluoride resin, PFA resin, glass or the like, glass container, or stainless steel.

  Since the reduction process of the present invention requires a pressurizing condition depending on the catalyst condition, when performing under a pressurizing condition, a pressure-resistant reactor is used and the reaction is carried out with the system sealed.

[About the second step (iodination step)]
Fluorinated alkyl-substituted ethyl halides represented by the general formula [2] obtained in the first step are iodinated to produce cancer fluoroalkyl-substituted ethyl iodides represented by the general formula [3]. .

  The iodination reaction of the present invention can be carried out in a batch reactor. Although the reaction conditions are described below, it does not preclude changing the reaction conditions to the extent that those skilled in the art can easily adjust the reaction conditions.

  The iodinating agent used in this iodination reaction is not particularly limited, but alkali metal salts such as lithium iodide, sodium iodide, potassium iodide, cesium iodide, tetramethylammonium iodide, tetrabutylal iodide. At least one compound selected from quaternary ammonium iodide salts such as umonium can be suitably used. Of these, sodium iodide and potassium iodide are more preferred because they are readily available at a low price, are easy to handle, and have low toxicity.

  The amount of the iodinating agent used in this iodination reaction is preferably 0.2 molar equivalent to 5 molar equivalents, more preferably 0.5 to 2 molar equivalents, relative to the fluorine-containing alkyl-substituted ethyl halides of the substrate. Less than 0.2 molar equivalent is not preferable because the iodinating agent is insufficient with respect to the substrate, and the conversion rate of the reaction is lowered. Moreover, when it exceeds 5 molar equivalent, since the iodinating agent which does not participate in reaction increases, it is not economically preferable.

  Although the present iodination reaction proceeds without using any solvent, a solvent can be used for the purpose of increasing the reaction selectivity, reaction rate, and operability. Ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, alcohol solvents such as methanol, ethanol, propanol and ethylene glycol, nitrile solvents such as acetonitrile and benzonitrile, N, N-dimethylformamide Amide solvents such as N, N-dimethylacetamide and N, N-dimethylimidazolidinone, sulfoxide solvents such as dimethyl sulfoxide, ether solvents such as diethyl ether, diisopropyl ether, dibutyl ether and tetrahydrofuran, methylene chloride, chloroform Selected from halogenated solvents such as carbon tetrachloride, aromatic hydrocarbon solvents such as benzene, toluene and xylene, and hydrocarbon solvents such as pentane, hexane and heptane. With one compound is used, these may be used alone or two or more kinds of mixed solvents. Of these, ketone solvents are preferred.

  The amount of solvent used in the present iodination reaction varies depending on the type of solvent and iodinating agent, and therefore cannot be determined uniquely, but the fluorine-containing alkyl-substituted ethyl halides of the substrate 20 wt% to 2000 wt% is preferable, and 100 wt% to 500 wt% is more preferable. If it is less than 20% by weight, even if a solvent is used, the reaction is not accelerated and the operability is not improved, which is not preferable. Moreover, since it will increase the cost which collect | recovers a product from a solvent when it exceeds 2000 weight%, it is not preferable.

  Although the present iodination reaction proceeds without using any additive, an additive can be used for the purpose of increasing selectivity and reaction rate. Additives include quaternary ammonium salts such as tetramethylammonium bromide and tetrabutylammonium bromide, quaternary phosphorus salts such as tetrabutylphosphine bromide, 12-crown-4, 15-crown-5, 18-crown-6 and the like. At least one compound selected from crown ethers and the like is preferred.

  The amount of additive used when this additive is used in this iodination reaction varies depending on the type of solvent, iodinating agent, and additive, so it cannot be uniquely determined. 0.05 weight%-50 weight% are preferable with respect to alkyl substituted ethyl halide, and 0.2 weight%-10 weight% are more preferable. If it is less than 0.05% by weight, even if an additive is used, there is no effect of improving the reaction selectivity or reaction rate, which is not preferable. On the other hand, if it exceeds 50% by weight, the effect of increasing the reaction rate or improving the reaction selectivity can no longer be expected.

  Although there is no special restriction | limiting in reaction temperature at the time of implementing this iodination reaction, it is -20 degreeC-250 degreeC normally, 20 degreeC-200 degreeC is preferable, and 50 degreeC-150 degreeC is especially preferable. If it is less than -20 degreeC, reaction will decelerate and it will not be desirable from a cost for cooling. On the other hand, if the temperature exceeds 250 ° C., side reactions tend to proceed and it is difficult to achieve selective synthesis.

[About the reactor]
The reactor for carrying out the iodination reaction is preferably a tetrafluoroethylene resin, chlorotrifluoroethylene resin, vinylidene fluoride resin, PFA resin, glass lined inside, glass container or stainless steel. .

  This reaction can be performed in an inert gas atmosphere, but even if the reaction is performed in the air, no significant difference is observed between the reaction in the inert gas atmosphere and the synthesis is performed particularly on a large scale. In some cases, it is preferable in terms of cost to perform the reaction in the atmosphere.

[Examples of desirable embodiments]
Although the method of practicing the present invention is not limited, the details of an example of a desirable embodiment will be described. The fluorine-containing alkyl-substituted ethyl iodides targeted in the present invention can be produced by combining the above-mentioned first step (reduction step) and second step (iodination step).

  First, the aspect about the process of the 1st step (reduction process) is shown. A raw material fluorine-containing alkyl-substituted vinyl halide and a catalyst are added to a reactor that can withstand the reaction conditions of this reduction reaction, and the mixture is sealed, and hydrogen is injected while stirring. After setting to a predetermined temperature, stirring is performed.

  The reaction proceeds gradually, the raw material fluorine-containing alkyl-substituted vinyl halides (general formula [1]) are reduced, and fluorine-containing alkyl-substituted ethyl halides (general formula [2]) are produced. At the same time, the side reaction proceeds to produce fluorine-containing alkyl-substituted ethyls (formula [3]).

  It is preferable to monitor the production of the target product by sampling or the like. It is preferable to complete the reaction until the production amount reaches the maximum value while taking into account the progress of the side reaction with the target reaction.

  The fluorine-containing alkyl-substituted ethyl halides represented by the general formula [2] produced by the method of the present reduction invention can be purified by applying a known method. For example, crude fluorine-containing alkyl-substituted ethyl taken out from the reaction vessel The catalyst can be removed from the halide by filtration, and high-purity fluorine-containing alkyl-substituted ethyl halide can be obtained by column chromatography, distillation purification, recrystallization, and the like.

  Subsequently, the fluorine-containing alkyl-substituted ethyl halides produced in the above reduction step are subjected to the second step (iodination step). Add the fluorine-containing alkyl-substituted ethyl halides, iodinating agent, and solvent produced in the above reduction step to a reactor that can withstand the reaction conditions of the iodination step, seal, and heat to a predetermined temperature while stirring. To do.

  In the reaction, it is preferable to monitor the production of the target product by sampling or the like. The reaction is preferably terminated at the point where the raw material fluorine-containing alkyl-substituted alkyl halide has disappeared.

  The fluorine-containing alkyl-substituted ethyl iodide represented by the general formula [3] produced by the method of the present invention is purified by applying a known method. For example, after separating the precipitated inorganic halogen salt by filtration, A crude organic substance is obtained by distilling off the solvent.

  The resulting crude organic matter can be purified by column chromatography, distillation, recrystallization and the like to obtain high-purity fluorine-containing alkyl-substituted ethyl iodides.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, it is not restricted to these embodiments.
Here, “%” of the compositional analysis value is a solvent component obtained by collecting a part of the reaction mixture or product and measuring an organic component dissolved in diethyl ether by gas chromatography. This represents the “area%” of the organic component excluding, and this number was used as the selectivity. Moreover, the value which subtracted the composition (%) of the raw material from 100 was made into the conversion rate.

  [Example 1] Reduction step (5% rhodium / activated carbon)

  In a 300 mL (liter) autoclave equipped with a thermometer, stirrer, sampling tube, and hydrogen introduction tube, 120 g of E-1-chloro-3,3,3-trifluoropropene (1233t) and 1 g of 5% rhodium / activated carbon In addition, hydrogen was injected at 2 MPa and stirred at room temperature.

  Stirring was continued at room temperature while maintaining the hydrogen pressure at 2 MPa with a regulating valve, and stirring was stopped when the conversion rate exceeded 80% after 48 hours. At this time, the composition of the organic substance is 20.1% of the raw material 1233t, 21.0% of the target 1-chloro-3,3,3-trifluoropropane, and 1,1,1-trifluoro of the byproduct. Propane was 58.6%, and formation of the target product was observed. The composition had more by-products than the target product. The results are shown in Table 1.

[Example 2] Reduction step (5% rhodium / alumina)
The reaction was carried out under the same conditions as in Example 1 except that the catalyst was 5% rhodium / alumina. The conversion rate after 53 hours was 75.3%. The composition of the organic substance is 24.7% for 1233t, 36.2% for 1-chloro-3,3,3-trifluoropropane, and 38.8% for 1,1,1-trifluoropropane. The composition was slightly higher than the target product. The results are shown in Table 1.

[Example 3] Reduction step (1% rhodium / alumina)
Examination was performed under the conditions in which the metal loading ratio of the catalyst of Example 2 was decreased and the amount of the supported catalyst was increased. That is, the reaction was performed under the same conditions as in Example 2 except that the catalyst was 1% rhodium / alumina and the catalyst amount was 2 g. The progress of the reaction was slower than in the case of Example 1 and Example 2, and the conversion rate was 28.3% after 47 hours. The composition of the organic substance is 71.7% for 1233t, 14.5% for 1-chloro-3,3,3-trifluoropropane, and 13.6% for 1,1,1-trifluoropropane. The composition was slightly higher than that of the by-product. The results are shown in Table 1.

[Example 4] Reduction step (1% rhodium / alumina)
In the same manner as in Example 3, 1% rhodium / alumina was used as a catalyst, and a study was conducted in which the charge amount of 1233t was increased. During the study, the autoclave capacity, the catalyst amount and the hydrogen pressure were increased.

  That is, 410 g of E-1-chloro-3,3,3-trifluoropropene (1233t) was added to a 1 L (liter) autoclave equipped with a thermometer, a stirrer, a sampling tube, and a hydrogen introduction tube, 1% rhodium / alumina. 4 g of hydrogen was added, 6 MPa of hydrogen was injected, and the mixture was stirred at room temperature.

  Stirring was continued at room temperature while maintaining the hydrogen pressure at 6 MPa with an adjustment valve. After 170 hours, the conversion rate exceeded 76%, so stirring was stopped. At this time, the composition of the organic substance is 51.3% for 1-chloro-3,3,3-trifluoropropane, 23.8% for 1233t, and 24.6% for 1,1,1-trifluoropropane, Compared to by-products, the target product had a composition about twice as large. The results are shown in Table 1.

  The reactor was ice-cooled, the residual pressure was released to the atmosphere, and then flash distilled to obtain 388 g of crude organic matter. The obtained crude organic substance was subjected to precision distillation, and a fraction having a boiling point of 44 to 46 ° C. was collected to obtain 182 g of 1-chloro-3,3,3-trifluoropropane. The purity was 99%. The yield from the raw material 1233t was 44%.

[Example 5] Reduction step (5% Pd / activated carbon)
The reaction of Example 1 was carried out in a 50 ml autoclave at 10 g of 1233t (raw material) charged, 0.1 g of 5% palladium / activated carbon, hydrogen pressure of 2.0 MPa, and room temperature. The conversion after 48 hours was 26.8%. As a result of confirming the composition of the organic matter, 1233t of the raw material was 73.2%, 1,1,1-trifluoropropane was 13.5%, and the target 1-chloro-3,3,3-trifluoropropane was 13. 3%, and it was confirmed that the target product and the by-product were produced to the same extent.

[Comparative Example 1] Reduction step (ruthenium / activated carbon catalyst)
The reaction of Example 5 was performed in a 50 ml autoclave at a charge of 1233 t (raw material) of 10 g, a catalyst of 5% ruthenium / activated carbon 0.1 g, a hydrogen pressure of 2.0 MPa, and room temperature. The conversion after 24 hours was 2.8%. As a result of confirming the composition of the organic substance, the raw material 1233t was 97.2%, 1,1,1-trifluoropropane 2.2%, and the target 1-chloro-3,3,3-trifluoropropane was slightly 0. 6%.

[Comparative Example 2] Reduction step (platinum / activated carbon catalyst)
The reaction of Example 5 was carried out in a 50 ml autoclave at a charge of 1233 t (raw material) of 10 g, a catalyst of 5% platinum / activated carbon 0.1 g, a hydrogen pressure of 2.0 MPa, and room temperature. The conversion after 48 hours was 8.8%, but the reaction was stopped. As a result of confirming the organic composition, the raw material 1233t was 91.2%, 1,1,1-trifluoropropane was 7.9%, and the target 1-chloro-3,3,3-trifluoropropane was only 1%. 0.0%.

[Example 5] Iodination step 50 g of 1-chloro-3,3,3-trifluoropropane, 68 g of sodium iodide and 100 g of acetone were added to a 300 mL autoclave equipped with a thermometer, a stirrer, and a sampling tube and sealed. . While stirring, the autoclave was heated in a 100 ° C. oil bath.

  Sampling was performed after 36 hours from the start of the reaction, and the conversion was over 90%, so the reaction was terminated. The contents of the autoclave were filtered and the precipitate was washed with acetone to obtain 212 g of 1,1,1-trifluoro-3-iodopropane solution. The resulting solution was subjected to precision distillation, and a fraction having a boiling point of 88 to 91 ° C. was collected to obtain 59 g of 1,1,1-trifluoro-3-iodopropane. The purity was 99.5%. The yield from the raw material 1-chloro-3,3,3-trifluoropropane was 70%.

Claims (7)

Fluorine-containing alkyl-substituted vinyl halide represented by the general formula [1]

[Wherein, Rf is a linear or branched fluorine-containing alkyl group having 1 to 6 carbon atoms, and is represented by the general formula C _a H _b F _c- (a: an integer of 1 to 6, b: 0 to (2 × an integer up to a), c: an integer of (2 × a) −b + 1), and X is a chlorine atom or a bromine atom. Is reduced with hydrogen in the presence of a catalyst containing at least one metal selected from palladium or rhodium, and a method for producing a fluorinated alkyl-substituted ethyl halide represented by the general formula [2].

[Wherein, Rf and X are the same as those in the general formula [1]. ] The catalyst is a supported catalyst in which the metal is supported by a carrier, and the carrier is at least one selected from alumina, activated carbon, fluorinated aluminum, diatomaceous earth, febroin, and silica gel. The manufacturing method of fluorine-containing alkyl-substituted ethyl halides as described in above. The method for producing a fluorine-containing alkyl-substituted ethyl halide according to any one of claims 1 and 2, wherein the ratio of the metal to the support in the catalyst is 0.1 to 5% by weight. The method for producing a fluorine-containing alkyl-substituted ethyl halide according to any one of claims 1 to 3, wherein the hydrogen pressure is from atmospheric pressure to 15 MPa. The method for producing an alkyl-substituted ethyl halide according to any one of claims 1 to 4, wherein the fluorine-containing alkyl group is a trifluoromethyl group. The method for producing a fluorinated alkyl-substituted ethyl halide according to any one of claims 1 to 5, wherein X in the general formula [1] or the general formula [2] is a chlorine atom. A fluorine-containing compound represented by the general formula [3], wherein the fluorine-containing alkyl-substituted ethyl halide represented by the general formula [2] obtained by the method according to any one of claims 1 to 7 is iodinated. A method for producing alkyl-substituted ethyl iodides.

[Wherein Rf is the same as in general formula [2]. ]