Pipeline continuous fluorination method using fluorine salt as fluorine source

Abstract

The invention discloses a pipelined continuous fluorination method using fluorine salt as a fluorine source, which comprises the following steps: dissolving fluoride salt in a water-containing polar aprotic solvent as reaction liquid A, and aryl (heterocyclic) Chloride is dissolved in the polar aprotic solvent as the reaction solution B, the polar aprotic solvent in the reaction solution A is the same as the polar aprotic solvent of the reaction solution B; by the reaction solution A after preheating and the reaction after preheating The reaction material composed of liquid B enters the reaction coil for fluorination reaction, and the reaction product flowing out of the reaction coil is post-processed to obtain the product. The method has the characteristics of no need to add a phase transfer catalyst, continuous production, low production cost and the like.

Description

technical field [0001] The invention relates to the field of fluorine chemical industry, in particular to a pipelined continuous fluorination method for aryl (heterocyclic) chlorides. Background technique [0002] Aryl (heterocyclic) fluorides are an important class of chemical intermediates and are widely used in the fields of medicine and pesticides. The method for preparing aryl (heterocyclic) fluorides by using aryl (heterocyclic) chlorides as raw materials through fluorine-chlorine exchange has the advantages of low cost and mature technology. There are two types of fluorine sources commonly used in industry: hydrogen fluoride and fluoride salts. The fluorination process using hydrogen fluoride as the fluorine source has the problems of serious equipment corrosion and high safety risks. The fluorine salt represented by cesium fluoride, potassium fluoride, sodium fluoride, etc. is cheap and easy to handle, and is an ideal fluorine source. [0003] However, fluoride sa...

AI Technical Summary

Problems solved by technology

This patent uses tetramethylammonium bromide as a phase transfer catalyst. Although the dissolution problem is solved, in order to completely dissolve the fluoride salt, it is necessary to add a far excess phase transfer catalyst compared with the tank reaction, and the process cost is greatly increased.

In addition: the data of this example also has certain problems: whether it is room temperature or 200 ° C, under the addition of 0.8g of tetramethylammonium bromide, 30g of potassium fluoride cannot be dissolved in 300ml of sulfolane; if it is necessary to achieve complete dissolution, not only Only a high temperature of 200°C is required, and at least several tens of grams of tetramethylammonium bromide are required

However, if potassium fluoride cannot be completely dissolved, it is impossible to achieve microchannel fluorination

[0007] At present, the industrial fluorination process of aryl (heterocyclic) chlorides still uses hydrogen fluoride as the main source of fluorine, which has high safety risks and frequent accidents

However, the fluorination process using fluorine salt as the fluorine source often requires the addition of a phase transfer catalyst, which is costly

The conventional kettle-type fluorination process still has the problems of large reactor equipment size, low production efficiency and unstable product quality

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