Multi-stage tubular electrolysis device for preparing octafluoropropane and preparation method

Abstract

The invention discloses a multi-stage tubular electrolysis device for preparing octafluoropropane by adopting an electrolysis method and a preparation method. The device comprises more than two electrolytic baths, local porous anodes, cathodes, liquid inlets, gas pipelines and gas outlets, wherein the electrolytic baths provide a closed electrolytic environment and store electrolytes; the anodes provide gas raw material channels and the fluorine element for reaction; the cathodes form an electronic loop; an electrolyte is added into the electrolytic baths through the liquid inlets; the electrolytic baths are connected through the gas pipelines, electrolysis gas of the previous electrolytic cell is cooled, and a gas channel is provided; and the octafluoropropane crude product gas is mainly discharged through the gas outlets. The device and the method have the advantages of simple production process, high octafluoropropane yield and the like.

Description

technical field [0001] The invention relates to the field of octafluoropropane preparation, in particular to an electrolysis device and a preparation method suitable for preparing octafluoropropane gas by electrolysis. Background technique [0002] Octafluoropropane has the characteristics of non-toxic, odorless, non-flammable, insoluble in water and oil, very small solubility in organic solvents, good electrical insulation, high dielectric rate, good thermal conductivity and physiological drug resistance. It is widely used in electronics, microelectronics, medicine and other industries; at present, the preparation method of octafluoropropane basically adopts chemical synthesis method, and the main methods are as follows: [0003] 1. Direct gas-phase fluorination of hydrocarbons and hexafluoropropylene, that is, hydrocarbons or hexafluoropropylene are directly fluorinated with elemental fluorine under the action of a catalyst. During the fluorination process, C-C bonds will ...

AI Technical Summary

Problems solved by technology

There are two problems in this method: one is that unreacted chlorofluoroalkanes are difficult to remove in the purification section; the other is that due to the influence of the electronegativity of adjacent fluorine atoms, it is difficult to replace Cl atoms with fluorine atoms, and the conversion rate is low;

This makes the process a batch-type preparation process. At the same time, cobalt trifluoride and cobalt difluoride are continuously transformed into each other, resulting in constant changes in the size of the internal molecular structure of the fluorinating agent, which eventually causes cobalt trifluoride to be pulverized and affects octafluoropropane. Yield

[0007] To sum up, due to the complex process or low conversion rate of the octafluoropropane chemical synthesis method, the researchers used the electrolysis method to prepare octafluoropropane in one step. The method was to disperse the gas raw material in anhydrous HF for electrolysis, and the anode F elements in HF are electrolyzed into F radicals, and F radicals react with gas raw materials to generate anode gas containing octafluoropropane; the cathode electrolyzes H ions in HF into H elements, and H elements combine to form hydrogen gas

This method has the advantages of simple process and stable anode product composition, but the electrolysis process has the problem that the carbon chain is easily broken, and impurities such as carbon tetrafluoride and hexafluoroethane are easily produced, resulting in a low yield of octafluoropropane; and in actual operation In the process, the height of the electrode exceeds 2m to ensure that the yield of octafluoropropane is not less than 50%, which increases the difficulty of the design and processing of the electrolytic cell

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