Hexafluoropropylene oxide oligoether derivative and process for the manufacture thereof

Abstract: An extremely reactive and highly copolymerizable hexafluoropropylene oxide oligoether derivative, to give bi- or ter-polymers with fluoroolefins and perfluoroalkyl vinyl ethers, which is represented by general formula: wherein X is a fluorine atom or trifluoromethyl group; and n is an integer of 2-5.

Description: BACKGROUND OF THE INVENTION The present invention relates to a novel hexafluoropropylene oxide (hereinafter referred to as "HFPO") oligoether derivative and a process for manufacturing the same. Perfluoroalkenes having a vinyl group (-CH=CH₂) at one end of the molecular chain, such as HFPO oligoether-group-containing ethylenes represented by the following general formula (3) are known in the art. (see, for example, USP 4,987,267) [wherein k is an integer of 2-5.] These fluorinated compounds, which are copolymerizable to give bi- or ter-copolymers with fluoroolefins, such as tetrafluoroethylene(TFE) and perfluoroalkylvinylethers, are useful synthetic intermediates for a variety of compounds. In particular, hybrid silicone compounds obtained by hydrosilylation of these compounds are known to be extremely useful in that not only do they exhibit excellent heat resistance and low temperature characteristics, but also they are water repellent and oil repellent, and have high stain resistance and a low surface energy. However, these fluorinated compounds, such as HFPO-oligoether-group-containing ethylenes suffer from their low reactivity and, thus have remained unsatisfactory synthetic intermediates. SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel HFPO oligoether derivative with improved reactivities and a process for the manufacture thereof. There is provided by the present invention a HFPO oligoether derivatives represented by general formula (1) below: [wherein X is a fluorine atom or trifluoromethyl group; and n is an integer of 2-5.] There is further provided by the present invention a process for the manufacture of the HFPO oligoether derivatives as set forth above comprising dehydroiodinating in the presence of a base an iodide compound represented by general formula (2) below: [wherein X is a fluorine atom or trifluoromethyl group; and n is an integer of 2-5.] The HFPO oligoether derivative of the present invention, as evident from general formula (1), structurally features a primary carbon for the carbon atom adjacent to the vinyl group and, thus, is more reactive than the conventional HFPO oligoether derivatives. For example, a conventional HFPO oligoether derivative represented by general formula (3) has a secondary carbon for the carbon atom adjacent to the vinyl group. This means that the vinyl group in the HFPO oligoether derivative of the present invention suffers only little steric hindrance, which suggests improved reactivities, for example, in copolymerization with fluoroolefins, such as TFE or in hydrosilylation, thereby extremely facilitating the synthesis of a variety of fluorinated silicone compounds and the like. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an IR spectrum of the HFPO oligoether derivative of the present invention obtained in Example 1. Figure 2 is an IR spectrum of the HFPO oligoether derivative of the present invention obtained in Example 2. DETAILED DESCRIPTION OF THE INVENTION The HFPO oligoether derivative of the present invention can be synthesized by dehydroiodinating in the presence of a base an iodide compound represented by general formula (2). The iodide represented by general formula (2) can be obtained, for example, by subjecting the corresponding iodide represented by general formula (4) below: [wherein X and n are as previously defined] and ethylene to an addition reaction at 70-80°C in the presence of azobisisobutyronitrile (AIBN). Examples of suitable bases to be used in the dehydroiodination reaction include alkali metal hydroxides, such as sodium hydroxide, potassium hydroxide, and cesium hydroxide, and particularly preferred examples are sodium hydroxide and potassium hydroxide. The reactant molar ratio of the iodide of general formula (2) used in the dehydroiodination reaction and the base is ideally 1:1, but it is normally 0.5:1 - 10:1, preferably 0.9:1 - 2.5:1. The dehydroiodination reaction is carried out by adding dropwise an iodide of general formula (2) into a solution of the above base in a suitable organic solvent. Suitable organic solvents which may be used are those capable of dissolving the base well and which are inert to the reaction and the products. Examples of suitable organic solvents are alcoholic solvents such as methanol, ethanol, n-propanol, and i-propanol, and most preferable ones are methanol and ethanol. The dehydroiodination reaction, which is an exothermic reaction, is preferably carried out with a dropwise addition of the iodide compound of general formula (2), with the temperature of the reaction system in the range of 20-70 °C , particularly 45-70°C . Care must be exercised so as not to make the dropwise addition rate too high, so that the reaction system temperature should not exceed the preferred temperature range. The temperature of the reaction system after completing the dropwise addition is preferably set in the range of 20-70 °C , particularly 50-70°C , and the reaction time after completing the dropwise addition is normally about 1-18 hours. This reaction can be followed gas chromatographically, and the completion of this reaction can be known by the depletion of the iodide of general formula (2). After completion of this reaction, the organic solvent and the byproduct salt are removed, followed by water washing, drying, and purifying, such as distillation to give HFPO oligoether derivatives, represented by general formula (1). The resultant HFPO oligoether derivatives, as explained above, are extremely reactive and highly copolymerizable to give bi- or ter-polymers with fluoroolefins, such as TFE, and the like, and fluoroalkylvinyl ethers, and the like, making them extremely useful synthetic intermediates for a variety of compounds. In particular, hybrid silicone compounds obtained by hydrosilylation of these HFPO oligoether derivatives exhibit excellent heat resistance and low temperature characteristics, water repellency and oil repellency, high staining resistance, and a low surface energy, which make them extremely useful. EXAMPLES The present invention is illustrated in more detail by reference to the following examples. EXAMPLE 1 In a 10ℓ separable flask equipped with a stirrer, a cooler, and a thermometer, was dissolved under a nitrogen stream 775 g (13.8 moles) of potassium hydroxide in 2,500 g of methanol. The solution was then heated on an oil bath to 40-50°C , to which was added dropwise in 5.5 hours a solution of 6,000 g (10.22 moles) of an iodide of the following formula. After completion of the dropwise addition, the mixture was heated and stirred for about 14 hours at 70°C . The mixture was then cooled to room temperature, the salt generated filtered off, and the bottom layer of the filtrate was separated. The separated liquid was then water washed, dried over anhydrous sodium sulfate, and distilled to give 4,171 g of the goal product (yield: 88.6%, BP: 133-134 °C /760Torr). The product was analyzed to give the results as shown in the following: ¹H-NMR: (CCl₄ solution, TMS internal standard, ppm) 5.7 (m, 3H, -C H =CH₂) ¹⁹F-NMR: (CCl₄ solution, CF₃COOH internal standard, ppm) -68.6 (1F, >C F -) -53.0 (2F, CF₃C F ₂CF₂O-) -41.4 (2F, -CF₂C F ₂CH=CH₂) -11.5 (2F, -OC F ₂CF₂CH=CH₂) - 7.1 (2F, -CF(CF₃)C F ₂O-) - 4.5 (8F, C F ₃CF₂C F ₂O-, -CF(C F ₃)CF₂O-) Infrared Absorption Spectrum (Liquid Film; KBr): The spectrum is given in Figure 1. MS(m/e): 335 (CF₃CF₂CF₂OCF(CF₃)CF₂-) 169 (CF₃CF₂CF₂-) 127 (-CF₂CF₂CH=CH₂) 100 (-CF(CF₃)-, -CF₂CF₂-) 69 (-CF₃) Elemental Analysis (%): Calculated: C: 25.86; H: 0.65; F: 69.61 Found C: 26.03; H: 0.57; F: 69.34 These results indicate the above compound to have a structural formula as follows: EXAMPLE 2 The same reaction as that of Example 1 was carried out except for using 80.7 g (95.5 mmoles) of an iodide of the following formula: 6.5 g (115.9 mmoles) of potassium hydroxide, and 21.0 g of methanol to give 57.5 g of a product (yield: 89.2%, BP: 88.5-90.0°C /20Torr). The product was analyzed to give the results as shown in the following: ¹H-NMR: (CCl₄ solution, TMS internal standard, ppm) 5.8 (m, 3H, -C H =C H ₂) ¹⁹F-NMR: (CCl₄ solution, CF₃COOH internal standard, ppm) -68.0 (3F, -C F (CF₃)CF₂O-) -53.0 (2F, CF₃C F ₂CF₂O-) -37.2 (2F, -CF(CF₃)C F ₂CH=) - 5.3 (5F, C F ₃CF₂C F ₂O-) - 3.8 (10F, -[CF(C F ₃)C F ₂O]₂-) - 2.7 (3F, -CF(C F ₃)CF₂CH=) Infrared Absorption Spectrum (Liquid Film; KBr): The spectrum is given in Figure 2. MS(m/e): 343 (-CF(CF₃)CF₂OCF(CF₃)CF₂CH=CH₂-) 177 (-CF(CF₃)CF₂CH=CH₂) 169 (CF₃CF₂CF₂-) 157, 113, 100 (-CF(CF₃ )-, -CF₂CF₂-) 77 (-CF₂CH=CH₂) 69 (-CF₃) Elemental Analysis(%): Calculated: C: 24.21; H: 0.43; F: 68.44 Found C: 24.10; H: 0.52; F: 68.58 These results indicate the above compound to have a structural formula as follows:

Claims: A hexafluoropropylene oxide oligoether derivative represented by general formula (1) below: wherein X is a fluorine atom or trifluoromethyl group; and n is an integer of 2-5. The oligoether derivative of claim 1, wherein n is 3 and X is a fluorine atom. The oligoether derivative of claim 1, wherein n is 4 and X is a trifluoromethyl group. A process for the manufacture of the oligoether derivative of claim 1, comprising dehydroiodinating in the presence of a base an iodide compound represented by general formula (2) below: wherein X is a fluorine atom or trifluoromethyl group; and n is an integer of 2-5.

Inventors: KOIKE NORIYUKI, TAKANO KOUJI, YAMAGUCHI HIROMASA, YAMAGUCHI KOUICHI, KOIKE, NORIYUKI, TAKANO, KOUJI, YAMAGUCHI, HIROMASA, YAMAGUCHI, KOUICHI
Applicants: SHINETSU CHEMICAL CO, SHIN-ETSU CHEMICAL CO., LTD.
Application year: 1993
Main classification: C07C43
IPC codes: C07C43, C07C41