Synthetic method of perfluoropolyether

Abstract

The invneiton discloses a synthetic method of perfluoropolyether. The synthetic method comprises the following steps of: reacting a first volume part of purified hexafluoropropylene gas and alkali metal fluoride in an aprotic solvent at 0 DEG C to 50 DEG C to obtain low polymer; cooling the temperature of the obtained low polymer to the range of -40 DEG C to -20 DEG C, and adding a second volume part of purified hexafluoropropylene gas for reaction with the low polymer to obtain perfluoropolyether. According to the synthetic method of perfluoropolyether disclosed by the invention, the synthetic process for feeding materials and controlling temperature in stages is adopted to prepare perfluoropolyether, so that the conversion rate of hexafluoropropylene reaches 99% and above; moreover, the prepared perfluoropolyether has high average molecular weight. Besides, the material hexafluoropropylene gas is purified by using alkali substances and silica gel, so that the used alkali substance and silica gel are low in cost and can be repeatedly used while the material gas reaches the using requirements. Meanwhile, in the process of synthesizing perfluoropolyether, the use of diluents is avoided, so that the process is simple and the cost is lower, therefore, the synthetic method is suitable for industrial application.

Description

technical field [0001] The invention relates to the technical field of polymer materials, in particular to a method for synthesizing perfluoropolyether. Background technique [0002] Perfluoropolyether is a colorless and transparent perfluoropolymer material. Compared with the molecular structure of ordinary polyether, perfluoropolyether replaces the C-H bond with the C-F bond, and the strong electronegative fluorine atom makes the attraction between the molecules smaller and has a smaller surface tension; The shielding effect of the chain makes it heat-resistant, oxidation-resistant, corrosion-resistant, radiation-resistant and non-combustible. High molecular weight perfluoropolyether has low volatility, wide liquid temperature range and excellent viscosity-temperature characteristics after stabilization treatment. It is used as an excellent lubricant in aerospace industry, electronics industry, electrical industry and nuclear industry, etc. field. [0003] At present, t...

AI Technical Summary

Problems solved by technology

[0003] At present, there are two main production technologies of perfluoropolyether. One is the photo-oxidative polymerization technology of tetrafluoroethylene or hexafluoropropylene. Although the production cost of this production technology is low, the process is complicated and the risk is high; the other is The first is perfluoroepoxide, such as the anionic polymerization method of hexafluoropropylene oxide or tetrafluorooxetane. This method has a simple and safe production process and is currently a widely used production method. However, its reaction conditions are Such as raw material purity, reaction temperature and material viscosity all have influence on raw material conversion rate, the average molecular weight of polymer product, and this just makes the perfluoropolyether product average molecular weight of preparation lower, and hexafluoropropylene oxide conversion rate is lower, Can not meet the actual application needs

[0004] The prior art discloses the process of using metal hydride to purify the raw material hexafluoropropylene oxide gas, and adding hexafluoropropylene as a diluent to reduce the viscosity of the material and prepare perfluoropolyether. However, the cost of metal hydride is relatively high. High, the diluent hexafluoropropylene is difficult to recycle, and the conversion rate of hexafluoropropylene oxide is low, and the average molecular weight of the prepared perfluoropolyether is low, which cannot meet the industrial requirements