Method for preparing hexafluoropropylene oxide oligomer

Abstract

The invention discloses a method for preparing hexafluoropropylene oxide oligomer. Alkali-metal fluoride salt, aprotic inertia polarity organic solvents, fluorine-containing organic solvents and perfluoro(2-methyl-3-oxahexanoyl)fluoride are used for preparing a homogeneous activation initiator, the homogeneous activation initiator is used for initiating a hexafluoropropylene oxide monomer to have a polymerization reaction, and then the hexafluoropropylene oxide oligomer with a high molecular weight is obtained. Meanwhile, a part of products and related solvents are recycled, and an environment-friendly recycle production effect is achieved.

Description

technical field [0001] The present invention relates to the preparation method of hexafluoropropylene oxide oligomer. Background technique [0002] Hexafluoropropylene oxide oligomer becomes perfluoropolyether oil after fluorination, due to its unique physical and chemical properties, such as heat resistance, oxidation resistance, radiation resistance, corrosion resistance, low volatility, good compatibility with materials, water resistance Solvent and non-flammable properties make it an extremely reliable lubricant in harsh environments. The main application fields include chemical industry, electronics, electrical, machinery, nuclear industry, aerospace, magnetic media, cosmetics and other fields. [0003] Perfluoropolyether oil can be manufactured into different products according to its average relative molecular weight, such as vacuum lubricating oil, sealing lubricating ester, compressor oil, reliability test fluid, heat transfer fluid, gas phase welding fluid, electro...

AI Technical Summary

Problems solved by technology

With the deepening of follow-up research, researchers believe that there are more impurities in commercial hexafluoropropylene oxide. For example, hexafluoropropylene oxide sold in the market generally contains some impure substances or by-products. If there is no reaction Hexafluoropropylene, hexafluoroacetone, perfluoropropionyl fluoride, perfluoroacetyl fluoride, hydrogen fluoride and water, etc., and these impurities have a greater impact on the polymerization reaction, so that hexafluoropropylene oxide with a higher molecular weight cannot be obtained Oligomer; U.S. Patent No. 3,412,148 reports a method for purifying hexafluoropropylene oxide. Molecular sieves are used to dry hexafluoropropylene oxide to remove moisture. This method can be used to prepare a compound with an average relative molecular mass of more than 5500 product, but he ignored the influence of other impure impurities in the raw material; U.S. Patent No. 4,356,291 introduced the method of using alkaline metal substances to remove various impurities in hexafluoropropylene oxide, and the purified hexafluoropropylene oxide can be prepared Hexafluoropropylene oxide oligomer with a higher average degree of polymerization; US Patent US360315 introduces a new polymerization method, that is, a product with an average degree of polymerization of more than 50 is prepared with a bifunctional initiator

U.S. Patent US20060199942 reports the method of using potassium fluoride / tetraethylene glycol dimethyl ether as a catalytic system to prepare hexafluoropropylene oxide oligomers with an average molecular weight between 2000 and 3000. Although this method eliminates the expensive and dry Difficult and toxic cesium fluoride, but the molecular weight of the product is not high enough to be of great commercial value

[0005] The prior art discloses the process of using metal hydrides to purify the raw material hexafluoropropylene oxide gas and hexafluoropropylene as a diluent to prepare hexafluoropropylene oxide oligomers, but there are metal hydrides with high prices and hexafluoropropylene oxides. It has the disadvantages of certain toxicity and difficulty in recycling, and the low reaction conversion rate of hexafluoropropylene oxide, and the average molecular weight of the prepared hexafluoropropylene oxide oligomer is low, which cannot meet the industrial requirements

Although a variety of methods for preparing hexafluoropropylene oxide oligomers using hexafluoropropylene oxide as raw materials have been disclosed in the prior art, these methods still have many shortcomings, such as low average molecular weight, poor reaction stability, and low reaction conversion rate. Low, difficult to recover raw materials, the most important thing is that it is impossible to carry out large-scale industrial production

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