Method for producing diiodide and diiodide-containing composition

Abstract

Provided is a method for producing a diiodide by reacting a crude composition containing a diiodide represented by I (CF2CF2) nI (in the formula, n is an integer of 1 or more) and at least one selected from the group consisting of an ether represented by I (CF2CF2) mOR1 (in the formula, m is an integer of 1 or more, and R1 is an organic group) and an ester represented by ICF2COOR2 (in the formula, R2 is an organic group) and a crude composition containing M (OH) p (in the formula, p is 1 or 2, and n is an integer of 1 or more) and an ester represented by ICF2COOR2 (in the formula, R2 is an organic group). M is an alkali metal or an alkaline earth metal) and an aqueous solution of water to prepare a mixture, the mixture is separated into a phase containing the diiodide and a phase containing water, and the phase containing the diiodide is recovered.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for producing diiodide and a composition containing diiodide. BACKGROUND

[0002] In Patent Literature 1, a method for producing an α-Ω-diiodofluorinated alkane is described, which is characterized by reacting 1,2-diiodotetrafluoroethane with tetrafluoroethylene in the presence of a catalytic amount of a free radical catalyst to form a telomer-like product of the following formula: I (CF2CF2)n n I (in the formula, n is an integer of 2 to 10), and absorbing the telomer-like product from the reaction mixture.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 47-2573 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In the present application, the object is to provide a method for producing diiodide with high purity.

[0008] METHOD FOR SOLVING THE PROBLEM

[0009] According to the present application, there is provided a method for producing diiodide, wherein

[0010] by mixing a crude composition containing at least one member selected from the group consisting of diiodide represented by general formula (1-1): I (CF2CF2)n n I (in the formula, n is an integer of 1 or more), and an ether represented by general formula (1-2): I (CF2CF2)mOR m (OR 1 (in the formula, m is an integer of 1 or more, R 1 is an organic group), and an ester represented by general formula (1-3): I CF2COOR 2 (in the formula, R 2 is an organic group), with an aqueous solution containing hydroxide represented by general formula (2-1): M (OH)p p (in the formula, p is 1 or 2, and M is an alkali metal or an alkaline earth metal) and water to prepare a mixture,

[0011] separating the above mixture into a phase containing the above diiodide and a phase containing water, and recovering the phase containing the above diiodide.

[0012] EFFECT OF THE INVENTION

[0013] According to the present application, it is possible to provide a method for producing diiodide with high purity. DETAILED DESCRIPTION

[0014] Hereinafter, a specific embodiment of the present application will be described in detail, but the present application is not limited to the following embodiment.

[0015] In Patent Literature 1, a manufacturing method of a fluorinated alkane α-ω-diiodide of a telomer nature product by a telomerization reaction of 1,2-diiodotetrafluoroethane as a telomer and tetrafluoroethylene as a main chain substance is proposed. In addition, it is described in Patent Literature 1 that if a telomer is desired, the telomer is separated by fractionation of a telomer mixture in a reduced pressure.

[0016] However, in a case where a telomer (diiodide) is separated and recovered by fractionation of a telomer nature product produced by such a conventional manufacturing method, there is a problem that each telomer cannot be recovered in a sufficient yield.

[0017] Therefore, the cause of the problem was intensively studied, and as a result, it was found that, by the telomerization reaction, an ether or an ester is generated in addition to the diiodide, and the ether or the ester in the generated reaction product hinders the separation of the diiodide by fractionation, which is the cause of the yield not being improved. Furthermore, a means for removing the ether or the ester generated by the telomerization reaction from the reaction product was intensively studied, and as a result, it was found that, by fractionation of the reaction product from which the ether or the ester was removed, diiodides different in the number of carbon atoms are separated, and each diiodide can be recovered in a high yield.

[0018] That is, according to the present application, there is provided a manufacturing method of a diiodide, in which

[0019] by mixing a crude composition containing at least one of a diiodide represented by General Formula (1-1): I(CF2CF2) n (I in the formula, n is an integer of 1 or more) and an ether represented by General Formula (1-2): I(CF2CF2) m OR 1 (I in the formula, m is an integer of 1 or more, R 1 is an organic group) and an ester represented by General Formula (1-3): ICF2COOR 2 (I in the formula, R 2 is an organic group) and an aqueous solution containing a hydroxide represented by General Formula (2-1): M(OH) p (I in the formula, p is 1 or 2, and M is an alkali metal or an alkaline earth metal) and water,

[0020] the above mixture is separated into a phase containing the above diiodide and a phase containing water, and the phase containing the above diiodide is recovered.

[0021] According to the production method of the present application, the ether or ester in the crude composition containing diiodide can be separated from the crude composition, and a composition containing diiodide at high purity can be recovered at a high yield. Furthermore, by distilling the composition containing diiodide at high purity by a method such as fractional distillation or steam distillation, diiodide having a target n number can be separated and recovered at a high yield.

[0022] Hereinafter, the production method of the present application will be described in more detail.

[0023] The present application relates to a production method of a composition containing diiodide at high purity. In the production method of the present application, a crude composition containing diiodide and at least one selected from the group consisting of an ether and an ester is mixed with an aqueous solution containing hydroxide and water to prepare a mixture, the resulting mixture is separated into two phases, and a phase containing diiodide at high purity is recovered.

[0024] In one embodiment, the crude composition is prepared by telomerization of 1,2-diiodotetrafluoroethane as a telomer and tetrafluoroethylene as a main chain material. By this telomerization, a crude composition containing an ether represented by general formula (1-2) or an ester represented by general formula (1-3) in addition to diiodide represented by general formula (1-1) is generated. If the crude composition is mixed with an aqueous solution containing hydroxide, the ether and ester in the crude composition react with the hydroxide and are decomposed. On the other hand, the diiodide is not decomposed and remains in the mixture. If the resulting mixture is left to stand, it is separated into two phases, a phase containing diiodide as a main component and a phase containing water or hydroxide as a main component. By recovering the phase containing diiodide as a main component, a composition containing diiodide at high purity can be produced.

[0025] That is, a composition containing diiodide represented by general formula (1-1): I(CF2CF2) n (I (in the formula, n is an integer of 1 or more) and at least one selected from the group consisting of an ether represented by general formula (1-2): I(CF2CF2) m OR 1 (in the formula, m is an integer of 1 or more, R 1 is an organic group) and an ester represented by general formula (1-3): ICF2COOR 2 (in the formula, R 2 is an organic group) is an important raw material for producing a composition containing diiodide at high purity.

[0026] The diiodide contained in the above crude composition is represented by general formula (1-1): I(CF2CF2) nI (in the formula, n is an integer of 1 or more). n can be an integer of 1 to 20, an integer of 1 to 10, or an integer of 1 to 8. In one embodiment, the crude composition contains at least diiodides represented by general formula (1-1) in which n is an integer of 1 to 8.

[0027] In one embodiment, the crude composition contains diiodides represented by general formula (1-1) in which n is an integer of 1 to 8, and contains diiodides represented by general formula (1-1) in which n is an integer of 9 or more.

[0028] The crude composition can contain at least diiodides represented by general formula (1-1), and for example, can contain only one kind of diiodides represented by general formula (1-1) in which n is an arbitrary value. However, the crude composition preferably contains at least two or more kinds of diiodides represented by general formula (1-1) in which n is different in value. That is, the crude composition is preferably a diiodide mixture containing two or more kinds of diiodides represented by general formula (1-1) in which n is different in value.

[0029] In one embodiment, the crude composition contains at least I(CF2CF2)I, I(CF2CF2)2I, and I(CF2CF2)3I as diiodides. In one embodiment, the crude composition contains at least eight kinds of diiodides represented by general formula (1-1) in which n is an integer of 1 to 8.

[0030] The crude composition contains at least one selected from the group consisting of an ether represented by general formula (1-2): I(CF2CF2) m OR 1 (in the formula, m is an integer of 1 or more, and R 1 is an organic group) and an ester represented by general formula (1-3): ICF2COOR 2 (in the formula, R 2 is an organic group) in addition to the diiodides.

[0031] The crude composition can be a crude composition containing diiodides represented by general formula (1-1) and ethers represented by general formula (1-2), a crude composition containing diiodides represented by general formula (1-1) and esters represented by general formula (1-3), or a crude composition containing diiodides represented by general formula (1-1) and both ethers represented by general formula (1-2) and esters represented by general formula (1-3).

[0032] The total content of the ethers represented by general formula (1-2) and the esters represented by general formula (1-3) in the crude composition is preferably 20.0% by mass or less, more preferably 10.0% by mass or less, and the lower limit is not particularly limited and can be 1.0% by mass or more, with respect to the mass of the crude composition. The total content of the ethers and the esters in the crude composition can be measured by gas chromatography analysis.

[0033] The content of the diiodide represented by General Formula (1-1) in the crude composition is preferably 80.0% by mass or more, more preferably 90.0% or more, and preferably 99.0% by mass or less, relative to the mass of the crude composition. The content of the diiodide in the crude composition can be determined by gas chromatography analysis.

[0034] In General Formula (1-2), m is an integer of 1 or more. m can be an integer of 2 or more, can be an integer of 20 or less, can be an integer of 10 or less, can be an integer of 8 or less, or can be an integer of 5 or less. In one embodiment, the crude composition contains at least an ether represented by General Formula (1-2) in which m is an integer of 2 to 5. In one embodiment, the crude composition contains an ether represented by General Formula (1-2) in which m is an integer of 2 to 5, and contains a diiodide represented by General Formula (1-2) in which m is an integer of 6 or more.

[0035] In General Formula (1-2), R 1 is an organic group. R 1 is preferably a hydrocarbon group, and more preferably an alkyl group or an aryl group. The number of carbon atoms of the hydrocarbon group and the alkyl group is preferably 1 to 30, more preferably 1 to 15, and further preferably 1 to 4. As the aryl group, a phenyl group is preferable. As R 1 , for example, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, a phenyl group, and the like can be exemplified. In the case where the crude composition is produced by the telomerization reaction using an organic peroxide, R 1 is formed by a hydrocarbon group derived from the organic peroxide.

[0036] In General Formula (1-3), R 2 is an organic group. R 2 is preferably a hydrocarbon group, and more preferably an alkyl group or an aryl group. The number of carbon atoms of the hydrocarbon group and the alkyl group is preferably 1 to 30, more preferably 1 to 15, and further preferably 1 to 4. As the aryl group, a phenyl group is preferable. As R 2 , for example, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, a phenyl group, and the like can be exemplified. In the case where the crude composition is produced by the telomerization reaction using an organic peroxide, R 2 is formed by a hydrocarbon group derived from the organic peroxide.

[0037] R 1 in General Formula (1-2) can be the same as or different from R 2 in General Formula (1-3). In one embodiment, R 1 in General Formula (1-2) is the same as R 2 in General Formula (1-3).

[0038] The aqueous solution mixed with the above-mentioned crude composition contains a hydroxide represented by General Formula (2-1): M(OH) p (In the formula, p is 1 or 2, and M is an alkali metal or an alkaline earth metal) and water.

[0039] In General Formula (2-1), M is an alkali metal or an alkaline earth metal, and is preferably at least one selected from the group consisting of Li, K, and Na, and more preferably K.

[0040] As the hydroxide represented by General Formula (2-1), at least one selected from the group consisting of LiOH, KOH, and NaOH is preferable, and further KOH is preferable.

[0041] The content of the hydroxide in the aqueous solution is preferably 1 mass% to the saturated solubility concentration of each hydroxide at 20°C with respect to the aqueous solution.

[0042] In the production method of the present application, the crude composition and the aqueous solution are mixed to prepare a mixture. The mixing ratio of the crude composition to the aqueous solution is preferably 1:99 to 99:1, more preferably 10:90 to 95:5, and further preferably 20:80 to 90:10, in terms of the mass ratio of the crude composition to the aqueous solution (crude composition:aqueous solution).

[0043] The mixture can be prepared, for example, by adding the aqueous solution to the crude composition all at once or sequentially or continuously. The mixing can be performed while stirring. For the stirring, a stirrer, a stirring blade, or the like can be used. Alternatively, the crude composition and the aqueous solution can be continuously circulated and mixed in a static mixer, a packed column, or the like. A transfer catalyst or an emulsifier can be added to the system to promote the mixing of the crude composition and the aqueous solution. If the aqueous solution is added to the crude composition, the mixture sometimes generates heat, and thus the aqueous solution can be added to the crude composition sequentially or continuously, for example, in such a manner that the temperature of the mixture is maintained in the range of 40 to 100°C.

[0044] The mixing of the crude composition and the aqueous solution can be performed, for example, in the temperature range of 40 to 150°C. If the temperature is too low, the crude composition, the aqueous solution, or the mixture can be heated to adjust to the above-mentioned temperature range. If the temperature is too high when the crude composition and the aqueous solution are mixed, the diiodide sometimes volatilizes or decomposes to reduce the yield, and thus the mixing temperature is preferably determined in consideration of the boiling point of the diiodide. In the case where the crude composition obtained by distilling the reaction product prepared by the telomerization reaction is used, the mixing temperature is preferably 50 to 90°C. In the case where the reaction product prepared by the telomerization reaction is directly used as the crude composition, the mixing temperature is preferably 50 to 150°C.

[0045] After the crude composition and the aqueous solution are mixed, the resulting mixture can be left to stand for 10 minutes to 24 hours while the temperature of the resulting mixture is maintained within the above-mentioned temperature range.

[0046] Next, the mixture obtained by mixing the crude composition and the aqueous solution is left to stand, and is separated into two phases, a phase containing diiodide as a main component and a phase containing water or hydroxide as a main component. If the resulting mixture is left to stand, it is usually separated into a lower phase containing diiodide as a main component and an upper phase containing water or hydroxide as a main component. By recovering the phase containing diiodide as a main component, a composition containing diiodide at a high purity can be produced. In the present application, the main component means a component whose mass ratio contained in the phase exceeds 50%.

[0047] The total content of the ether represented by General Formula (1-2) and the ester represented by General Formula (1-3) in the composition containing diiodide obtained by the production method of the present application is preferably 500 mass ppm or less, more preferably 100 mass ppm or less, with no particular lower limit, and can be 0.1 mass ppm or more or 1.0 mass ppm or more. The total content of the ether and the ester in the composition can be measured by gas chromatography analysis.

[0048] The content of the diiodide represented by General Formula (1-1) in the composition is preferably greater than 99.0 mass%, more preferably 99.9 mass% or more. The content of the diiodide in the composition can be measured by gas chromatography analysis.

[0049] In the production method of the present application, the crude composition can be produced by telomerization in which 1,2-diiodotetrafluoroethane is used as a telomer and tetrafluoroethylene is used as a main chain material.

[0050] In addition, in the production method of the present application, a reaction product produced by telomerization can be used as the crude composition, or a part of a distillate or a residue obtained by distilling a reaction product produced by telomerization can be used as the crude composition. Distillation of the reaction product produced by telomerization can be performed by a known method such as fractional distillation, steam distillation, and the like.

[0051] The 1,2-diiodotetrafluoroethane used in the telomerization can be produced by a known production method such as the production method described in Japanese Patent Application Publication No. S43-11884, the production method described in U.S. Patent No. 2424667, and the like.

[0052] The telomerization reaction can be performed using an organic peroxide. In the telomerization reaction performed in the presence of an organic peroxide, the organic peroxide is decomposed to generate radicals, the generated radicals abstract iodine atoms of the 1,2-diiodotetrafluoroethane, thereby newly generating alkyl radicals, and the addition reaction of tetrafluoroethylene to the alkyl radicals is performed.

[0053] As the organic peroxide, dialkyl peroxides such as diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, tertiary butyl peroxyisobutyrate, tertiary butyl peroxyneopentanoate, and the like; dialkyl peroxides such as di-tert-butyl peroxide; diacyl peroxides such as benzoyl peroxide; and the like can be exemplified.

[0054] The amount of use of tetrafluoroethylene is preferably 0.01 to 100 moles per 1 mole of the 1,2-diiodotetrafluoroethane.

[0055] The amount of use of the organic peroxide is preferably 0.01 to 2 moles per 1 mole of the 1,2-diiodotetrafluoroethane.

[0056] The reaction temperature of the 1,2-diiodotetrafluoroethane and tetrafluoroethylene can be appropriately selected, and is preferably -78 to 200°C. In addition, the reaction temperature of the 1,2-diiodotetrafluoroethane and tetrafluoroethylene is preferably a temperature equal to or higher than the 10-hour half-life of the organic peroxide, and is preferably lower than the decomposition temperature of the substrate and the product.

[0057] The reaction pressure of the 1,2-diiodotetrafluoroethane and tetrafluoroethylene can be appropriately selected, and is preferably 0 to 5.0 MPaG. In the gas phase of the reaction, a diluent gas such as carbon dioxide, nitrogen, and the like can be co-present with tetrafluoroethylene, as implemented in Japanese Patent No. 6545187 and Japanese Laid-Open Patent Publication No. 53-144507. The reaction time of the 1,2-diiodotetrafluoroethane and tetrafluoroethylene can be appropriately selected, and is preferably 0.1 to 96 hours.

[0058] In the production method of the present application, the phase containing diiodide can be recovered, and the recovered phase can be distilled. The recovered phase containing diiodide is a composition containing diiodide at a high purity, and the ether represented by General Formula (1-2) and the ester represented by General Formula (1-3) are removed or reduced. By distilling such a composition, compared to the case where a composition containing at least either one of the ether represented by General Formula (1-2) or the ester represented by General Formula (1-3) is distilled, it is possible to separate and recover diiodide having a target n number at a high yield.

[0059] The distillation can be performed by a known method such as fractional distillation, steam distillation. The diiodide has a high boiling point and is easily thermally decomposed, and thus it is preferable to perform the distillation on the phase containing the diiodide under reduced pressure. The pressure at the time of the distillation is preferably 0 MPaG or lower, more preferably -0.09 MPaG or lower. By the distillation, a fraction containing I(CF2CF2)I as a main component, a fraction containing I(CF2CF2)2I as a main component, a fraction containing I(CF2CF2)3I as a main component, and the like can be recovered from the phase containing the diiodide.

[0060] In one embodiment, a fraction containing I(CF2CF2)3I as a main component is recovered from the phase containing the diiodide by distillation. In one embodiment, a fraction containing I(CF2CF2)I as a main component, a fraction containing I(CF2CF2)2I as a main component, and a fraction containing I(CF2CF2)3I as a main component are respectively recovered from the phase containing the diiodide by distillation.

[0061] In one embodiment of the production method of the present application,

[0062] A crude composition containing at least I(CF2CF2)I, I(CF2CF2)2I, and I(CF2CF2)3I, and containing at least one selected from the group consisting of an ether represented by general formula (1-2) and an ester represented by general formula (1-3) is prepared by a telomerization reaction using 1,2-diiodotetrafluoroethane as a telomer and tetrafluoroethylene as a main chain material,

[0063] The crude composition is subjected to distillation, and a fraction containing I(CF2CF2)I as a main component is recovered,

[0064] The residue obtained by the above distillation (residue remaining after the recovery of the fraction containing I(CF2CF2)I as a main component) is subjected to distillation, and a fraction containing I(CF2CF2)2I as a main component is recovered,

[0065] A mixture is prepared by using the residue obtained by the above distillation (residue remaining after the recovery of the fraction containing I(CF2CF2)2I as a main component) as a crude composition, and mixing the residue with an aqueous solution containing a hydroxide represented by general formula (2-1) and water.

[0066] The obtained mixture is separated into a phase containing a diiodide and a phase containing water, and the phase containing the diiodide is recovered,

[0067] The phase containing the diiodide is subjected to distillation, and a fraction containing I(CF2CF2)3I as a main component is recovered.

[0068] According to the production method of this embodiment, I(CF2CF2)3I can be recovered with high purity and at a high yield.

[0069] In one embodiment of the production method of the present application,

[0070] The crude composition containing at least I(CF2CF2)I, I(CF2CF2)2I, and I(CF2CF2)3I, and at least one selected from the group consisting of an ether represented by general formula (1-2) and an ester represented by general formula (1-3) is prepared by a telomerization reaction using 1,2-diiodotetrafluoroethane as a telomer and tetrafluoroethylene as a main chain material,

[0071] The crude composition is mixed with an aqueous solution containing a hydroxide represented by general formula (2-1) and water, thereby preparing a mixture,

[0072] The resulting mixture is separated into a diiodide-containing phase and a water-containing phase, and the diiodide-containing phase is recovered,

[0073] The diiodide-containing phase is subjected to distillation, and a fraction containing I(CF2CF2)I as a main component is recovered,

[0074] The residue obtained by the above distillation (residue remaining after the fraction containing I(CF2CF2)I as a main component is recovered) is subjected to distillation, and a fraction containing I(CF2CF2)2I as a main component is recovered,

[0075] The residue obtained by the above distillation (residue remaining after the fraction containing I(CF2CF2)2I as a main component is recovered) is subjected to distillation, and a fraction containing I(CF2CF2)3I as a main component is recovered.

[0076] According to the production method of this embodiment, I(CF2CF2)I, I(CF2CF2)2I, and I(CF2CF2)3I can be recovered with high purity and at a high yield, respectively.

[0077] The embodiments have been described above, but it is understood that various changes can be made in the modes and details without departing from the spirit and scope of the claims.

[0078] <1> According to a first aspect of the present application, there is provided a production method of a diiodide, wherein

[0079] by a diiodide represented by general formula (1-1): I(CF2CF2) n I (in the formula, n is an integer of 1 or more) and at least one selected from the group consisting of an ether represented by general formula (1-2): I(CF2CF2) m OR 1 (in the formula, m is an integer of 1 or more, and R1 an ether represented by general formula (1-3): ICF2COOR 2 (wherein, R 2 an ester represented by general formula (1-4): I(CF2CF2) p

[0080]

[0081] <2> According to a second aspect of the present application, there is provided the production method according to the first aspect, wherein, after the phase containing the diiodide is recovered, the phase is subjected to distillation.

[0082] <3> According to a third aspect of the present application, there is provided the production method according to the first aspect or the second aspect, wherein the crude composition contains at least I(CF2CF2)I, I(CF2CF2)2I and I(CF2CF2)3I.

[0083] <4> According to a fourth aspect of the present application, there is provided the production method according to the third aspect, wherein, after the phase containing the diiodide is recovered, the phase is subjected to distillation, whereby a fraction containing I(CF2CF2)3I as a main component is recovered.

[0084] <5> According to a fifth aspect of the present application, there is provided the production method according to any one of the first aspect to the fourth aspect, wherein the crude composition is produced by telomerization of 1,2-diiodotetrafluoroethane as a telomer and tetrafluoroethylene as a main chain material.

[0085] <6> According to a sixth aspect of the present application, there is provided the production method according to any one of the first aspect to the fourth aspect, wherein a reaction product is produced by telomerization of 1,2-diiodotetrafluoroethane as a telomer and tetrafluoroethylene as a main chain material, and the crude composition is produced by subjecting the reaction product to distillation.

[0086] <7> According to a seventh aspect of the present application, there is provided the production method according to the fifth aspect or the sixth aspect, wherein the telomerization is performed in the presence of an organic peroxide.

[0087] <8> According to an eighth aspect of the present application, there is provided the production method according to any one of the first aspect to the seventh aspect, wherein

[0088] the diiodide is represented by general formula: I(CF2CF2) n I (wherein, n is an integer of 1 to 8)​​

[0089] the ether is of a general formula: I(CF2CF2) m OR 1 (in the formula, R 1 is an alkyl group having 1 to 4 carbon atoms, and m is an integer of 2 to 5), an ether,

[0090] the ester is of a general formula: ICF2COOR 2 (in the formula, R 2 is an alkyl group having 1 to 4 carbon atoms), an ester,

[0091] the content of the diiodide in the crude composition is preferably 80.0 mass% to 99.0 mass% relative to the mass of the crude composition,

[0092] the total content of the ether and the ester in the crude composition is 1.0 mass% to 20.0 mass% relative to the mass of the crude composition,

[0093] the hydroxide is at least one selected from the group consisting of LiOH, KOH, and NaOH,

[0094] the content of the hydroxide in the aqueous solution is 1 mass% or more and less than the saturated solubility concentration of the hydroxide at 20°C relative to the aqueous solution,

[0095] the mass ratio of the crude composition to the aqueous solution (crude composition:aqueous solution) is 20:80 to 90:10,

[0096] the temperature at the time of mixing the crude composition with the aqueous solution is 40°C to 150°C.

[0097] <9>According to a ninth aspect of the present invention, there is provided a composition containing at least one selected from the group consisting of a diiodide of a general formula (1-1): I(CF2CF2) n (in the formula, n is an integer of 1 or more), an ether of a general formula (1-2): I(CF2CF2) m OR 1 (in the formula, m is an integer of 1 or more, and R 1 is an organic group), and an ester of a general formula (1-3): ICF2COOR 2 (in the formula, R 2 is an organic group),

[0098] the total content of the ether and the ester is 500 mass ppm or less relative to the mass of the composition.

[0099] <10>According to a tenth aspect of the present invention, there is provided the composition according to the ninth aspect, in which,

[0100] The diiodide is of the general formula: I (CF2CF2) n I (in the formula, n is an integer of 1 to 8), an ether represented by the general formula:

[0101] The ether is of the general formula: I (CF2CF2) m OR 1 (in the formula, R 1 is an alkyl group having 1 to 4 carbon atoms, and m is an integer of 2 to 5), an ester represented by the general formula:

[0102] The ester is of the general formula: I (CF2COOR 2 (in the formula, R 2 is an alkyl group having 1 to 4 carbon atoms), an ether represented by the general formula:

[0103] The content of the diiodide is greater than 99.0 mass% with respect to the mass of the composition.

[0104] Examples

[0105] Next, examples will be given to describe embodiments of the present application, but the present application is not limited to the examples.

[0106] Synthesis Example 1

[0107] ICF2CF2I (222 g) and diisopropyl peroxydicarbonate (IPP) (4.4 g) were charged into a 200-ml SUS316-made autoclave having a stirring blade. The inside of the tank was cooled to -15°C, and the inside of the tank was made vacuum, and tetrafluoroethylene (TFE) (54 g) was charged from the gas phase. To make TFE react with ICF2CF2I, the temperature was raised to 55°C. The reaction pressure decreased as TFE was consumed in the reaction (the reaction pressure was 2.8 MPaG at the start of the reaction, and became 1.8 MPaG after 14 hours had passed).

[0108] After 14 hours of reaction had passed, the temperature was allowed to drop, and after the tank temperature was confirmed to have reached room temperature, the residual pressure was released to atmospheric pressure. The reaction crude (249 g) remaining in the reaction tank was recovered, and the composition of the obtained telomer mixture (reaction crude) was confirmed by gas chromatography. The results are shown in Table 1.

[0109] The gas chromatography was performed under the following conditions.

[0110] Measuring device: SHIMADZU GC-2014

[0111] Column: Silicone SE-30 (15%)

[0112] Temperature conditions of the column: 50°C for 5 minutes, 10°C / minute, 250°C for 5 minutes

[0113] Temperature of the vaporization chamber: 250°C

[0114] Detector temperature: 250℃

[0115] Detector: TCD

[0116] Type of carrier gas: Helium

[0117] Sample injection volume: 1 μl

[0118] Example 1

[0119] The following describes the steps of adding an aqueous KOH solution to the telomer mixture obtained in Synthesis Example 1 to decompose and remove the ethers and esters.

[0120] 153 g of the telomer mixture obtained in Synthesis Example 1 was added to a reactor equipped with a stir bar and a capacitor in a 100 ml three-necked flask. The mixture was then heated to 50°C, and 35 g of a 48% KOH aqueous solution was added simultaneously while adjusting the amount of KOH added to maintain the tank temperature at 50–60°C. After the KOH addition was completed, the reaction was maintained at 50–60°C for another 2 hours.

[0121] The reaction product was obtained as a mixture of two phases: an aqueous KOH solution phase and a telomer phase. The results of gas chromatography analysis of the lower phase (telomer phase) are shown in Table 1. The disappearance of the ether and ester was confirmed. Liquid-liquid separation was performed from the reaction mixture, and 142 g of the telomer phase was recovered. This amount is considered approximately quantitative if the ether and ester are considered to have been decomposed and removed.

[0122] In Tables 1 and 2, diiodides, ethers, and esters are listed as compounds with the following chemical formulas.

[0123] Diiodide: I(CF2CF2) n I (where n is an integer as shown in Table 1)

[0124] Ether: I(CF2CF2) m OCH(CH3)2 (where m is an integer as shown in Table 1)

[0125] Ester: ICF2COOCH(CH3)2

[0126]

[0127] Example 2

[0128] Example 2 shows an example of removing ethers from the residue generated by fractional distillation of the reactants obtained by the telomerization reaction.

[0129] The diiodide (n = 1) and the diiodide (n = 2) were each separated and recovered by fractionation of the telomer mixture obtained in Synthesis Example 1, and a residue was recovered. The results of analysis of the residue using gas chromatography are shown in Table 2.

[0130] A reactor having a stirrer and connected to a capacitor was charged with the residue 125 g in a 100 ml three-necked flask. After heating to 50°C, the charging of a 48 mass% KOH aqueous solution was started. The reaction proceeded by the addition of KOH, and heat generation was confirmed. The charging was performed while adjusting the amount of the 48 mass% KOH aqueous solution so as to maintain the temperature in the tank at 90 to 100°C. The KOH was charged over 2 hours, and 34 g of KOH was charged. After the end of the KOH charging, the temperature was maintained at 90 to 100°C, and the reaction was further continued for 3 hours.

[0131] The reaction product liquid after the reaction was separated into a KOH aqueous solution phase and a telomer phase. The results of analysis of the telomer phase using gas chromatography are shown in Table 2.

[0132]

[0133] Comparative Example 1

[0134] The telomer mixture obtained in Synthesis Example 1 was distilled under reduced pressure at 4.5 kPa by a conventional method using a 15-stage all-color distillation apparatus made of glass. The results are shown below.

[0135] Separation yield of diiodide (n = 1) (purity 90% or more): 85%

[0136] Separation yield of diiodide (n = 2) (purity 90% or more): 52%

[0137] Example 3

[0138] The telomer phase obtained in Example 1 was distilled under reduced pressure at 4.5 kPa by a conventional method using a 15-stage all-color distillation apparatus made of glass. The results are shown below.

[0139] Separation yield of diiodide (n = 1) (purity 90% or more): 89%

[0140] Separation yield of diiodide (n = 2) (purity 90% or more): 94%

[0141] It was confirmed from the results of Comparative Example 1 and Example 3 that the recovery yield of the telomer (diiodide) was improved by removing impurities in the raw material by neutralization.

Claims

1. A method for manufacturing diiodide, wherein, By using the general formula (1-1): I(CF2CF2) n The diiodide shown in I and the choice of general formula (1-2): I(CF2CF2) m OR 1 The ether shown is of general formula (1-3): ICF2COOR 2 Crude compositions of at least one of the ester groups shown, and those containing general formula (2-1): M(OH) p The mixture is prepared by mixing the hydroxide and an aqueous solution of water, as shown in formula (1-1), where n is an integer greater than or equal to 1, and m is an integer greater than or equal to 1 in formula (1-2), R 1 For organic groups, in general formula (1-3), R 2 For organic groups, in general formula (2-1), p is 1 or 2, and M is an alkali metal or alkaline earth metal. The mixture is separated into a phase containing the diiodide and a phase containing water, and the phase containing the diiodide is recovered.

2. The manufacturing method according to claim 1, wherein, After recovering the phase containing diiodide, the phase is distilled.

3. The manufacturing method according to claim 1 or 2, wherein, The crude composition contains at least I(CF2CF2)I, I(CF2CF2)2I and I(CF2CF2)3I.

4. The manufacturing method according to claim 3, wherein, After recovering the phase containing diiodide, the phase is distilled to recover the fraction containing I(CF2CF2)3I as the main component.

5. The manufacturing method according to any one of claims 1 to 4, wherein, The crude composition was prepared by telomerization of 1,2-diiodotetrafluoroethane as the telomer and tetrafluoroethylene as the main chain.

6. The manufacturing method according to any one of claims 1 to 4, wherein, The reaction product was prepared by telomerization of 1,2-diiodotetrafluoroethane as the telomer and tetrafluoroethylene as the main chain, and the crude composition was prepared by distillation of the reaction product.

7. The manufacturing method according to claim 5 or 6, wherein, The telomerization reaction occurs in the presence of organic peroxides.

8. The manufacturing method according to any one of claims 1 to 7, wherein, The diiodide has the general formula: I(CF2CF2) n The diiodide shown in I, in this general formula, where n is an integer from 1 to 8, The ether has the general formula: I(CF2CF2) m OR 1 The ether shown, in the general formula, R 1 It is an alkyl group with 1 to 4 carbon atoms, and m is an integer from 2 to 5. The ester has the general formula: ICF2COOR 2 The ester shown, in the general formula, R 2 It is an alkyl group having 1 to 4 carbon atoms. The content of the diiodide in the crude composition is 80.0% to 99.0% by mass relative to the mass of the crude composition. The total content of the ether and the ester in the crude composition is 1.0% to 20.0% by mass relative to the mass of the crude composition. The hydroxide is at least one selected from the group consisting of LiOH, KOH, and NaOH. The content of the hydroxide in the aqueous solution is more than 1% by mass relative to the aqueous solution and is less than the saturated solubility concentration of the hydroxide at 20°C. The mass ratio of the crude composition to the aqueous solution, i.e., the crude composition: aqueous solution, is 20:80 to 90:

10. The temperature at which the crude composition is mixed with the aqueous solution is 40°C to 150°C.

9. A composition comprising the general formula (1-1): I(CF2CF2) n The diiodide shown in I and the choice of general formula (1-2): I(CF2CF2) m OR 1 The ether shown is of general formula (1-3): ICF2COOR 2 At least one of the groups of esters shown, in general formula (1-1), n ​​is an integer greater than or equal to 1, in general formula (1-2), m is an integer greater than or equal to 1, R 1 For organic groups, in general formula (1-3), R 2 It is an organic group. The total content of the ether and the ester is less than 500 ppm by mass relative to the composition.

10. The composition according to claim 9, wherein, The diiodide has the general formula: I(CF2CF2) n The diiodide shown in I, in this general formula, where n is an integer from 1 to 8, The ether has the general formula: I(CF2CF2) m OR 1 The ether shown, in the general formula, R 1 It is an alkyl group with 1 to 4 carbon atoms, and m is an integer from 2 to 5. The ester has the general formula: ICF2COOR 2 The ester shown, in the general formula, R 2 It is an alkyl group having 1 to 4 carbon atoms. The content of the diiodide is greater than 99.0% by mass relative to the mass of the composition.

Images