Preparation method of perfluoromethyl vinyl ether

Abstract

The invention relates to a preparation method of perfluoromethyl vinyl ether, and belongs to the field of fluorine-containing plastics. The preparation method comprises the following steps of: preparing CF3OK by using potassium fluoride, carbonyl fluoride and tetrafluoroethylene as initial raw materials and using acetonitrile as a solvent in the absence of a catalyst, and reacting the CF3OK with tetrafluoroethylene in the presence of a little amount of water to prepare the perfluoromethyl vinyl ether serving as a target product. The reaction temperature is normal temperature in the whole process, the reaction of the first step is under normal pressure, and the reaction of the second step does not need external pressure, so the reaction conditions are easily realized and easily controlled;moreover, the equipment used in the preparation process has simple structure, so the cost of the whole production process is low; the intermediate products do not need high-purity separation, so the middle separation step is reduced, and the synthesis cost is reduced; meanwhile, the acetonitrile solvent can be recycled and is not released to the air space, so the method has no pollution and is environment-friendly; therefore, the method can be applied to large-scale industrialized production.

Description

technical field [0001] The invention belongs to the field of special fluorine-containing comonomers, in particular to carbonyl fluoride (COF 2 ), potassium fluoride (KF) and tetrafluoroethylene (TFE) as a method for preparing perfluoromethyl vinyl ether (PMVE) from raw materials. Background technique [0002] Perfluoromethyl vinyl ether (PMVE) can be used as a raw material in the production and preparation of various fluoropolymers such as fluoroplastics and fluororubbers, and is an important monomer for the preparation of modified fluororubbers and modified fluoroplastics. For example: PMVE can be copolymerized with tetrafluoroethylene to form fluororubber. This kind of fluororubber has the advantages of polytetrafluoroethylene heat resistance and corrosion resistance of various chemical reagents; under the condition of contacting superheated steam, this kind of fluororubber can exist stably One year; in the lye environment, the continuous use time can also exceed 3000 hou...

AI Technical Summary

Problems solved by technology

Yet this method cannot stop the generation of tetrafluoroethyl ether in the preparation process, and to K 2 CO 3 or Na 2 CO 3 , solvent, the water content in the catalyzer have very strict requirement, and the solvent after the reaction and catalyzer are difficult to recycle and use, cause a large amount of solvent, catalyzer waste, and cause certain environmental problem (Russ.J.Appl.Chem., 2005, 1640-1645; CA101659602A; UA3114778; Journal of Polymer Science, Part A: Polymer Chem., 1968, 398-405)

In addition, US patent (UA 3321532) reported that metal oxide (SiO 2 , CaO, ZnO, etc.) as a catalyst, the method of removing the acid fluoride group by pyrolysis of the acid fluoride ether at 300 ° C to obtain a fluorine-containing vinyl ether; the product obtained by this method contains a small amount of tetrafluoroethyl ether by-product, which is A by-product ether is difficult to separate by ordinary methods, so the cost of the subsequent treatment process is greatly increased

In addition, there are literature and patent reports that carbonyl fluoride and CFCl=CFCl are used as raw materials to synthesize PMVE. The process of catalyst pretreatment and activation in this method is relatively complicated and takes a long time, and the target product needs to be collected by low-temperature condensation and reflux, and the production cost is relatively high. Higher (WO 2009 / 150091, Journal of Polymer Science, Part A: General Papers 1965, 4065-4074 and Chinese patent CA1775722A)

The raw materials HFPO and CFCl=CFCl used in the above methods have not been realized large-scale industrial production, and the price is expensive