Perfluoropolyether electrochemical capping method

Abstract

The invention belongs to the technical field of electrochemical fluorination, and in particular relates to a perfluoropolyether electrochemical end capping method. Using perfluoropolyether whose end group is hydrogen-containing functional group as raw material, after vacuum dehydration and degassing treatment, electrochemical fluorination reaction is carried out with anhydrous hydrogen fluoride in an electrolytic cell containing electrolyte, and the crude product is washed with alkali and water to obtain Perfluorinated perfluoropolyether products. The invention is suitable for electrochemically capping perfluoropolyethers of various structures, and has the advantages of simple process, cheap and easily available reagents, relatively safe operation process, easy purification and high purity of the product, and is beneficial to industrial production and application.

Description

Technical field[0001]The present invention belongs to the art of electrochemical fluorination, and more particularly to a perfluoropolyether electrochemical seal method.Background technique[0002]PerfluoropolyEther, PFPE is an important organic fluorine compound having a high thermal stability, excellent chemical inert, wider liquid temperature range, low volatility, excellent adhesion characteristics, non-combustible Sex and significant lubrication performance, etc., widely used in the aerospace industry, nuclear industry, electronics industry, chemical industry, automotive industry, cosmetics and other fields. The whole fluoropolyether is formed by the process of the preparation of the intermediate product, and the acyl fluoride end group has a high chemical activity, which is easy to hydrolyzate as a carboxylic acid, and can also be converted into other functional groups, such as hydrogen-containing functional groups. If it is used directly as a lubricant, it is easy to react with...

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.