Perfluoropolyether electrochemical end capping method

Abstract

The invention belongs to the technical field of electrochemical fluorination, and particularly relates to a perfluoropolyether electrochemical end capping method, which comprises: carryingout vacuum dehydration degassing treatment on hydrogen-containing functional group-terminated perfluoropolyether used as a raw material, carrying out an electrochemical fluorination reaction with anhydrous hydrogen fluoride in an electrolyte-containing electrolytic cell, and carrying out alkali washing and water washing on the crude product to obtain the perfluorinated perfluoropolyether product. According tothe invention, the method is suitable for electrochemical end capping of perfluoropolyethers with various structures, the process is simple, the used reagents are cheap and easy to obtain, the operation process is safe, the product is easy to purify and high in purity, and the method is suitable for industrial production and application.

Description

technical field [0001] The invention belongs to the technical field of electrochemical fluorination, and in particular relates to an electrochemical end-capping method of perfluoropolyether. Background technique [0002] Perfluoropolyether (PFPE) is an important organic fluorine compound with high thermal stability, excellent chemical inertness, wide liquid temperature range, low volatility, excellent viscosity-temperature characteristics, non-flammable It is widely used in the aerospace industry, nuclear industry, electrical and electronic industry, chemical industry, automobile industry, cosmetics and other fields due to its excellent performance and remarkable lubricating properties. During the preparation process of perfluoropolyether, an intermediate product whose end group is acyl fluoride will be generated. The acyl fluoride end group has high chemical activity and can be easily hydrolyzed into carboxylic acid, and can also be converted into other functional groups, s...

AI Technical Summary

Problems solved by technology

[0003] The currently reported methods for fluorinating perfluoropolyether mainly include: one is direct fluorination with fluorine gas, such as introducing pure fluorine gas or diluting fluorine gas with nitrogen in the reactor of a special material, as described in the patent US3665041. Fluorination of perfluoropolyetheryl fluoride, the advantage of this method is that few other elements are introduced into the product, the disadvantage is that the corrosion resistance of the equipment is high, the reaction is not complete (unless the reaction time is long enough), and the utilization rate of fluorine gas is low , fluorine gas is poisonous and dangerous; the second is as disclosed in patents US4755330 and US3555100, under the catalysis of strong Lewis acids such as fluorides or oxyfluorides of Al, Ti, V, Co, Ni, Sb, etc. Perfluoropolyether acid fluoride is decarboxylated, and the catalyst used in this method is expensive, and impurities such as catalyst by-products are contained in perfluoropolyether and are not easy to separate; the third is as introduced in the patent US4664766, under photocatalysis, fluorine gas is used to carry out fluorine decarboxylation. Chemical, the yield and conversion rate of this method are high, but the structure of photochemical reaction equipment is complicated. In order to ensure that the equipment is not corroded, the control of water content in the reaction system is highly required, and there are specific requirements for the intensity and wavelength of light.

[0004] The above methods of fluorinating and capping perfluoropolyethers all have problems such as complicated process and difficulty in industrial production.