| The separation of hexafluoropropylene oxide (HFPO) from hexafluoropropylene (HFP) by an extractive distillation has been researched.First, the author designed the equipment for determining data of vapor-liquid equilibrium. The dependability of the equipment had been tested through vapor-liquid equilibrium of the ethanol and benzene system.The column and operating parameters of gas chromatography for analyzing HFPO and HFP had been determined through many tests. They are as follows:The gas chromatography column: a stainless steel tube of 3m length and 2mm diameter. The column is filled up with 15%Kel-FWax/GDX105(80-100 mesh)Carrier gas: gas of hydrogen, the total inlet pressure is 0.2MPa, the pressure of the fore part of column is 0. 1Mpa;Column temperature: 40℃;The results of gas chromatography analysis are good for HFPO and HFP .Several solvents have been tested through the forementioned vapor-liquid equilibrium equipment for their extractive capability. The solvent D alters the relative volatility of HFPO vs HFP to 2.606; The solvent B alters the relative volatility of HFPO vs HFP to 2.204; The solvent C alters the relative volatility of HFP vs HFPO to 1.277.According to the industrial requirement, the content of HFPO is more than 99.5% (weight percent); the content of HFP is more than 98%. Suppose the content of HFPO is 50% in the mixture. The thermal condition of the feed is fed with saturated vapor. The reflux ratio 4.5 is chosen. An extractive distillation column was designed to separate the mixture of HFPO and HFP with solvent D. The parameters of the extractive distillation column are that the number of perfect plates for the column is 13; the number of perfect plates for the rectifying section is 7; the number of perfect plates for the stripping section is 6;the feed plate is the 8th plate.A process was proposed to separate HFPO from HFP by an extractive distillationand recover HFP in the mixture of HFP and the extractive solvent.
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