METHOD FOR PRODUCING FLUOROPOLYETHER

Abstract

A process for preparing a low-molecular weight fluoropolyether containing an acid fluoride by decomposing a triflate or trifluoroacetate of a fluoropolyether having a hydroxyl group in the presence of a Lewis acid.

Claims

1. A process for preparing a low-molecular weight fluoropolyether containing an acid fluoride by decomposing a triflate or trifluoroacetate of a fluoropolyether having a hydroxyl group in the presence of a Lewis acid.

2. The process as defined in claim 1, wherein the fluoropolyether having a hydroxyl group is one having a recurring unit of —(CF.sub.2CF.sub.2O)x(CF.sub.2O)y-, and x and y are a real number of 1 to 100.

3. The process as defined in claim 1, wherein the fluoropolyether having a hydroxyl group is one having a recurring unit of —(CF.sub.2CF.sub.2CF.sub.2O)z-, and z is a real number of 1 to 100.

4. The process as defined in claim 1, wherein the fluoropolyether having a hydroxyl group is one having a recurring unit of —(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)n-, and n is a real number of 1 to 100.

5. The process as defined in claim 1, wherein the triflate is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)x(CF.sub.2O)yCF.sub.2CH.sub.2OTf, TfOCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O)x(CF.sub.2O)yCF.sub.2CH.sub.2OTf, A-(CF.sub.2CF.sub.2CF.sub.2O)zCF.sub.2CF.sub.2CH.sub.2OTf, TfOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O)zCF.sub.2CF.sub.2CH.sub.2OTf, A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)nCF.sub.2CF.sub.2CF.sub.2CH.sub.2OTf, and TfOCH.sub.2CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)nCF.sub.2CF.sub.2CF.sub.2CH.sub.2OTf, wherein A is fluoroalkoxy, Tf is CF.sub.3SO.sub.2, and x, y, z and n are a real number of 1 to 100.

6. The process as defined in claim 1, wherein the trifluoroacetate is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)x(CF.sub.2O)yCF.sub.2CH.sub.2OTfa, TfaOCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O)x(CF.sub.2O)yCF.sub.2CH.sub.2OTfa, A-(CF.sub.2CF.sub.2CF.sub.2O)zCF.sub.2CF.sub.2CH.sub.2OTfa, TfaOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O)zCF.sub.2CF.sub.2CH.sub.2OTfa, A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)nCF.sub.2CF.sub.2CF.sub.2CH.sub.2OTfa, and TfaOCH.sub.2CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)nCF.sub.2CF.sub.2CF.sub.2CH.sub.2OTfa, wherein A is fluoroalkoxy, Tfa is CF.sub.3CO, and x, y, z and n are a real number of 1 to 100.

7. The process as defined in claim 1, wherein the acid fluoride is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-CF.sub.2COF, FOC—CF.sub.2O(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-CF.sub.2COF, A-(CF.sub.2CF.sub.2CF.sub.2O)za-CF.sub.2CF.sub.2COF, FOC—CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O)za-CF.sub.2CF.sub.2COF, A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-CF.sub.2CF.sub.2CF.sub.2COF, and FOC—CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-CF.sub.2CF.sub.2CF.sub.2COF, wherein A is fluoroalkoxy, 0.1x≦xa≦0.9x, 0.1y≦ya≦0.9y, 0.1z≦za≦0.9z, 0.1n≦na≦0.9n, and x, y, z and n are a real number of 1 to 100.

8. The process as defined in claim 2, wherein x and y are each a real number of 1 to 30, z is a real number of 1 to 30, and n is a real number of 1 to 30.

9. The process as defined in claim 1, wherein the acid fluoride is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-CF.sub.2COF, FOC—CF.sub.2O(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-CF.sub.2COF, A-(CF.sub.2CF.sub.2CF.sub.2O)za-CF.sub.2CF.sub.2COF, FOC—CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O)za-CF.sub.2CF.sub.2COF, A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-CF.sub.2CF.sub.2CF.sub.2COF, and FOC—CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-CF.sub.2CF.sub.2CF.sub.2COF, and the low-molecular weight fluoropolyether is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-B, A-(CF.sub.2CF.sub.2CF.sub.2O)za-B, and A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-B, wherein A is fluoroalkoxy, B is fluoroalkyl, 0.1x≦xa≦0.9x, 0.1y≦ya≦0.9y, 0.1z≦za≦0.9z, and 0.1n≦na≦0.9n.

10. The process as defined in claim 1, wherein the triflate is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)x(CF.sub.2O)yCF.sub.2CH.sub.2OTf, TfOCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O)x(CF.sub.2O)yCF.sub.2CH.sub.2OTf, A-(CF.sub.2CF.sub.2CF.sub.2O)zCF.sub.2CF.sub.2CH.sub.2OTf, TfOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O)zCF.sub.2CF.sub.2CH.sub.2OTf, A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)nCF.sub.2CF.sub.2CF.sub.2CH.sub.2OTf, and TfOCH.sub.2CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)nCF.sub.2CF.sub.2CF.sub.2CH.sub.2OTf, the acid fluoride is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-CF.sub.2COF, FOC—CF.sub.2O(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-CF.sub.2COF, A-(CF.sub.2CF.sub.2CF.sub.2O)za-CF.sub.2CF.sub.2COF, FOC—CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O)za-CF.sub.2CF.sub.2COF, A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-CF.sub.2CF.sub.2CF.sub.2COF, and FOC—CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-CF.sub.2CF.sub.2CF.sub.2COF, and the low-molecular weight fluoropolyether is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-B, A-(CF.sub.2CF.sub.2CF.sub.2O)za-B, and A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-B, wherein A is fluoroalkoxy, B is fluoroalkyl, Tf is CF.sub.3SO.sub.2, x, y, z and n are a real number of 1 to 100, 0.1x≦xa≦0.9x, 0.1y≦ya≦0.9y, 0.1z≦za≦0.9z, and 0.1n≦na≦0.9n.

11. The process as defined in claim 1, wherein the trifluoroacetate is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)x(CF.sub.2O)yCF.sub.2CH.sub.2OTfa, TfaOCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O)x(CF.sub.2O)yCF.sub.2CH.sub.2OTfa, A-(CF.sub.2CF.sub.2CF.sub.2O)zCF.sub.2CF.sub.2CH.sub.2OTf, TfaOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O)zCF.sub.2CF.sub.2CH.sub.2OTfa, A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)nCF.sub.2CF.sub.2CF.sub.2CH.sub.2OTfa, and TfaOCH.sub.2CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)nCF.sub.2CF.sub.2CF.sub.2CH.sub.2OTfa, the acid fluoride is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-CF.sub.2COF, FOC—CF.sub.2O(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-CF.sub.2COF, A-(CF.sub.2CF.sub.2CF.sub.2O)za-CF.sub.2CF.sub.2COF, FOC—CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O)za-CF.sub.2CF.sub.2COF, A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-CF.sub.2CF.sub.2CF.sub.2COF, and FOC—CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-CF.sub.2CF.sub.2CF.sub.2COF, and the low-molecular weight fluoropolyether is at least one selected from the group consisting of A-(CF.sub.2CF.sub.2O)xa(CF.sub.2O)ya-B, A-(CF.sub.2CF.sub.2CF.sub.2O)za-B, and A-(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O)na-B, wherein A is fluoroalkoxy, B is fluoroalkyl, Tfa is CF.sub.3CO, x, y, z and n are a real number of 1 to 100, 0.1x≦xa≦0.9x, 0.1y≦ya≦0.9y, 0.1z≦za≦0.9z, and 0.1n≦na≦0.9n.

Description

EXAMPLES

[0037] The invention will be described in more detail with reference to the following examples to which, however, the invention is not limited.

Example 1

[0038] Preparation of A-(CF.sub.2CF.sub.2CF.sub.2O) zCF.sub.2CF.sub.2CH.sub.2OTf (Compound 1) A=CF.sub.3CF.sub.2CF.sub.2O—, Tf=CF.sub.3SO.sub.2—

[0039] In an argon atmosphere, 100 g of trifluoromethane-sulfonic anhydride was added dropwise for one hour to a mixture of 570 g of dichloromethane, 285 g of a fluoropolyether of the formula CF.sub.3CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O) zCF.sub.2CF.sub.2CH.sub.2OH (2004 in number average molecular weight and 1.25 in molecular weight distribution) and 34 g of pyridine. The mixture was stirred at room temperature for 17 hours. The mixture was thereafter washed with water, dewatered and purified by silica gel column chromatography, affording 282 g of Compound 1.

[0040] Compound 1 was a colorless transparent liquid and 1.74 g/cm.sup.3 in density at 20° C. Compound 1 was identified by NMR with the result shown. Compound 1 was 2158 in number average molecular weight which was obtained by a method for determining terminal group using .sup.19F-NMR (same as hereinafter).

[0041] .sup.19F-NMR (solvent: none, reference material: OCF.sub.2CF.sub.2CF.sub.2O in the obtained product being taken as −129.7 ppm)

[0042] δ=−129.7 ppm

[0043] [20F, —OCF.sub.2CF.sub.2CF.sub.2O—]

[0044] δ=−83.7 ppm

[0045] [40F, —OCF.sub.2CF.sub.2CF.sub.2O—]

[0046] δ=−124.7 ppm

[0047] [2F, —OCF.sub.2CF.sub.2CH.sub.2OSO.sub.2CF.sub.3]

[0048] δ=−86.8 ppm

[0049] [2F, —OCF.sub.2CF.sub.2CH.sub.2OSO.sub.2CF.sub.3]

[0050] δ=−76.0 ppm

[0051] [3F, —OCF.sub.2CF.sub.2CH.sub.2OSO.sub.2CF.sub.3]

[0052] δ=−130.7 ppm

[0053] [2F, CF.sub.3CF.sub.2CF.sub.2O—]

[0054] δ=−84.7 ppm

[0055] [2F, CF.sub.3CF.sub.2CF.sub.2O—]

[0056] δ=−82.4 ppm

[0057] [3F, CF.sub.3CF.sub.2CF.sub.2O—]

[0058] z=10.2

[0059] .sup.1H-NMR (solvent: none, reference material: D.sub.2O)

[0060] δ=3.2 ppm

[0061] [2H, —OCF.sub.2CF.sub.2CH.sub.2OSO.sub.2CF.sub.3]

Example 2

[0062] Preparation of a mixture (Mixture 1) of CF.sub.3CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zaCF.sub.2CF.sub.2COF (Compound 2), FOCCF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zaCF.sub.2CF.sub.2COF (Compound 3) and CF.sub.3CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zaCF.sub.2CF.sub.2CF.sub.3 (Compound 4)

[0063] In an argon atmosphere, 57 g of Compound 1 (2158 in number average molecular weight and 1.23 in molecular weight distribution) and 3 g of aluminum chloride were heated for reflux at 250° C. for 2 hours. After cooled to room temperature, solid reaction byproducts were filtered off to obtain 28 g of Mixture 1 of Compound 2, Compound 3 and Compound 4 as a filtrate.

[0064] Mixture 1 was a light yellow transparent liquid and 1.69 g/cm.sup.3 in density at 20° C. Mixture 1 was identified by NMR with the result shown. Mixture 1 was 1045 in number average molecular weight.

[0065] .sup.19F-NMR (solvent: none, reference material: OCF.sub.2CF.sub.2CF.sub.2O in the obtained product being taken as −129.7 ppm)

[0066] δ=−129.7 ppm

[0067] [9F, —OCF.sub.2CF.sub.2CF.sub.2O—]

[0068] δ=−83.7 ppm

[0069] [17F, —OCF.sub.2CF.sub.2CF.sub.2O—]

[0070] δ=−86.3 ppm

[0071] [2F, —OCF.sub.2CF.sub.3COF]

[0072] δ=−122.1 ppm

[0073] [2F, —OCF.sub.3CF.sub.2COF]

[0074] δ=−21.7 ppm

[0075] [1F, —OCF.sub.2CF.sub.3COF]

[0076] δ=−130.7 ppm

[0077] [2F, CF.sub.3CF.sub.2CF.sub.2O—]

[0078] δ=−84.7 ppm

[0079] [2F, CF.sub.3CF.sub.2CF.sub.2O—]

[0080] δ=−82.4 ppm

[0081] [3F, CF.sub.3CF.sub.2CF.sub.2O—]

[0082] za=4.28

Example 3

[0083] Preparation of TfaOCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O).sub.x(CF.sub.2O).sub.yCF.sub.2CH.sub.2OTfa (Compound 5)

Tfa=CF.SUB.3.CO—

[0084] In an argon atmosphere, 50 g of trifluoroacetic anhydride was added dropwise for one hour to 200 g of a fluoropolyether of the formula HOCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O) x (CF.sub.2O).sub.yCF.sub.2CH.sub.2OH (2071 in number average molecular weight and 1.15 in molecular weight distribution). The mixture was stirred at room temperature for 17 hours. Thereafter, low-boiling components were removed by an evaporator, affording 202 g of Compound 5.

[0085] Compound 5 was a colorless transparent liquid and 1.69 g/cm.sup.3 in density at 20° C. Compound 5 was identified by NMR with the result shown. Compound 5 was 2265 in number average molecular weight.

[0086] .sup.19F-NMR (solvent: none, reference material: OCF.sub.2CF.sub.2CF.sub.2CF.sub.2O in the obtained product being taken as −125.8 ppm)

[0087] δ=−52.1 ppm, −53.7 ppm, −55.4 ppm

[0088] [21F, —OCF.sub.2O—]

[0089] δ=−78.7 ppm, −80.6 ppm

[0090] [4F, —CF.sub.2CH.sub.2OCOCF.sub.3]

[0091] δ=−76.7 ppm

[0092] [6F, —CF.sub.2CH.sub.2OCOCF.sub.3]

[0093] δ=−89.1 ppm, −90.7 ppm

[0094] [40F, —OCF.sub.2CF.sub.2O—]

[0095] x=10.1, y=10.4

[0096] .sup.1H-NMR (solvent: none, reference material: D.sub.2O)

[0097] δ=5.0 ppm

[0098] [4H, —OCF.sub.2CH.sub.2OCOCF.sub.3]

Example 4

[0099] Preparation of a mixture (Mixture 2) of CF.sub.3CF.sub.2O(CF.sub.2CF.sub.2O).sub.xa (CF.sub.2O).sub.yaCF.sub.2CF.sub.2COF (Compound 6), FOCCF.sub.2O(CF.sub.2CF.sub.2O).sub.xa (CF.sub.2O).sub.yaCF.sub.2COF (Compound 7) and CF.sub.3CF.sub.2O(CF.sub.2CF.sub.2O).sub.xa (CF.sub.2O).sub.yaCF.sub.2CF.sub.3 (Compound 8)

[0100] In an argon atmosphere, 60 g of Compound 5 (2265 in number average molecular weight and 1.14 in molecular weight distribution) and 6 g of aluminum oxide were heated for reflux at 250° C. for 2 hours. After cooled to room temperature, solid reaction byproducts were filtered off to obtain 30 g of Mixture 2 of Compound 6, Compound 7 and Compound 8 as a filtrate.

[0101] Mixture 2 was a light yellow transparent liquid and 1.70 g/cm.sup.3 in density at 20° C. Mixture 2 was identified by NMR with the result shown. Mixture 2 was 968 in number average molecular weight. .sup.19F-NMR (solvent: none, reference material: OCF.sub.2CF.sub.2CF.sub.2O in the obtained product being taken as −125.8 ppm)

[0102] δ=−52.1 ppm, −53.7 ppm, −55.4 ppm

[0103] [8F, —OCF.sub.2O—]

[0104] δ=−78.7 ppm, −80.6 ppm

[0105] [4F, —CF.sub.2CH.sub.2OCOCF.sub.3]

[0106] δ=−76.7 ppm

[0107] [6F, —CF.sub.2CH.sub.2OCOCF.sub.3]

[0108] δ=−89.1 ppm, −90.7 ppm

[0109] [16.4F, —OCF.sub.2CF.sub.2O—]

[0110] za=4.10, ya=4.18

Reference Example 1

[0111] Preparation of a mixture (Mixture 3) of CF.sub.3CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zaCF.sub.2CF.sub.2CH.sub.2OH (Compound 9), HOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zaCF.sub.2CF.sub.2CH.sub.2OH (Compound 10) and CF.sub.3CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zaCF.sub.2CF.sub.2CF.sub.3 (Compound 11)

[0112] In an argon atmosphere, 10 ml of dehydrated THF is mixed with 0.6 g of LiAlH.sub.4 and ice-cooled. To a mixture was added dropwise a solution of 3 g of Mixture 1 (1045 in number average molecular weight) obtained in Example 2 dissolved in HFE-7100. After the addition, the mixture was stirred for one night at room temperature. To the mixture was added methanol and excess of LiAlH.sub.4 was deactivated, then washed with acid and washed with water. The mixture was dried over dehydrating agent, and the agent was filtered off. The filtrate was concentrated to give 2.4 g of Mixture 3 containing Compound 9, Compound 10 and Compound 11.

[0113] Mixture 3 was a light yellow transparent liquid and 1.65 g/cm.sup.3 in density at 20° C. Mixture 3 was identified by NMR with the result shown. Mixture 3 was 981 in number average molecular weight. .sup.19F-NMR (solvent: none, reference material: OCF.sub.2CF.sub.2CF.sub.2O in the obtained product being taken as −129.7 ppm)

[0114] δ=−129.7 ppm

[0115] [8F, —OCF.sub.2CF.sub.2CF.sub.2O—]

[0116] δ=−83.7 ppm

[0117] [16F, —OCF.sub.2CF.sub.2CF.sub.2O—]

[0118] δ=−86.4 ppm

[0119] [2F, —OCF.sub.2CF.sub.2CH.sub.2OH]

[0120] δ=−127.5 ppm

[0121] [2F, —OCF.sub.2CF.sub.2CH.sub.2OH]

[0122] δ=−130.7 ppm

[0123] [2F, CF.sub.3CF.sub.2CF.sub.2O—]

[0124] δ=−84.7 ppm

[0125] [2F, CF.sub.3CF.sub.2CF.sub.2O—]

[0126] δ=−82.4 ppm

[0127] [3F, CF.sub.3CF.sub.2CF.sub.2O—]

[0128] za=4.01

[0129] .sup.1H-NMR (solvent: none, reference material: D.sub.2O)

[0130] δ=4.0 ppm

[0131] [2H, —OCF.sub.2CF.sub.2CH.sub.2OH]

[0132] δ=4.3 ppm

[0133] [1H, —OCF.sub.2CF.sub.2CH.sub.2OH]

INDUSTRIAL APPLICABILITY

[0134] In the present invention, it is possible to prepare a fluoropolyether having a molecular weight lower than a starting fluoropolyether and containing an acid fluoride by modifying a hydroxyl group of the starting fluoropolyether to a triflate or trifluoroacetate and cleaving the fluoropolyether with heating in the presence of a Lewis acid.