Method for preparing fluoride through reaction of solid material and fluorine gas

Abstract

The invention relates to a method for preparing fluoride through reaction of a solid material and fluorine gas. The solid material is directly dispersed in the inert solvent, the selectivity is high, the inert solvent does not react with fluorine gas, and the purity of the product is not influenced. The selection range of the inert solvent is wide, fluorine nitrogen is introduced, the fluorine nitrogen can be uniformly diffused through the gas disperser, the stirrer can realize full contact of fluorine and materials, and the purity and yield of the product are ensured by secondary collection. Fluorine nitrogen and solid materials react to generate corresponding fluorides, meanwhile, the reaction time is shortened, and the reaction efficiency is improved; the reaction temperature is accurately controlled, the risk of side reaction is reduced, and the product purity is improved; the probability that materials are carried to a valve or a pipeline by gas is reduced, the economic consumption of equipment maintenance is reduced, and meanwhile, a secondary collector is arranged, so that the reaction yield is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical engineering, in particular to a method for preparing fluoride by reacting solid material with fluorine gas. Background Art

[0002] Traditional solid material and fluorine gas reaction devices mostly use static reactors (gas-solid reaction), which have uneven fluorine gas distribution and are prone to local over-fluorination or side reactions. Fluorine gas is highly corrosive and conventional materials (such as stainless steel) are easily corroded, resulting in a short device life and product contamination, and a high risk of fluorine gas leakage. The material contacts the fluorine gas slowly, and it is necessary to wait for the upper layer to be consumed before it can contact the material in the lower layer, and the reaction time is long. Temperature control is difficult, and some reactions suddenly release a large amount of heat, resulting in side reactions such as decomposition of products due to excessive temperature. The powder mesh size is small, and fluorine and nitrogen gas are continuously introduced, which may be carried away by the gas, causing blockage of subsequent pipelines or valves, reducing yields and increasing maintenance costs. Some solid materials will use solvents such as acetonitrile and ether, which will react with fluorine gas, increasing the consumption of fluorine gas and the possibility of producing by-products. Therefore, a method for preparing fluorides by reacting solid materials with fluorine gas is designed.

[0003] The Xinjiang Nonferrous Metals Research Institute produced arsenic pentafluoride using fluorine gas and arsenic powder. Research data revealed a relatively low yield of 28% to 40%. This may be due to the arsenic powder's tendency to float. When fluorine gas is blown into the reactor, it is easily carried out of the reactor with the gas, clogging subsequent valves and pipes and contributing to the low yield. In the event of a leak, the arsenic powder would float in the air and could be easily inhaled, posing a significant safety hazard. Furthermore, experimental experience has shown that the reaction between arsenic and fluorine gas releases a significant amount of heat, which can easily lead to excessively high reaction temperatures and damage to the reactor.

[0004] Chinese patent CN109179341A discloses a method for preparing tellurium hexafluoride. Tellurium hexafluoride is obtained by direct contact reaction of tellurium powder with fluorine gas and subsequent purification, with a yield of 80% to 85%. However, the reaction requires one or more reactors, requiring extensive equipment, and the yield is low. This suggests that the reaction of solid powder with fluorine gas (a gas-solid reaction) can result in material being carried away by the gas, leading to a low yield.

[0005] Chinese patent CN101920937A discloses a preparation method and reaction equipment of iodine pentafluoride, in which iodine solid is placed above liquid iodine pentafluoride or iodine pentafluoride solution, and then fluorine gas is passed into liquid iodine pentafluoride or iodine pentafluoride solution to react. In this method, iodine pentafluoride and iodine need to be mixed into a mixed system, and the equipment structure is more complicated. The reaction is an exothermic reaction, and the reaction temperature is too high, and it is easy to generate the by-product iodine heptafluoride, so it is necessary to accurately control the reaction temperature. At the same time, iodine elemental substance can form iodine vapor, forming a gas-gas reaction, and the reaction temperature is more difficult to control. Summary of the Invention

[0006] In order to solve the above problems, the purpose of the present invention is to provide a method for preparing fluoride by reacting solid material with fluorine gas. The solid material is directly dispersed in an inert solvent, which has high selectivity. At the same time, the inert solvent does not react with fluorine gas and does not affect the purity of the product. The solid material is dispersed in an inert solvent, and the range of solvent selection is wide. Fluorine and nitrogen gas are introduced, and the fluorine and nitrogen gas can be evenly diffused through a gas disperser. The agitator can achieve full contact between fluorine gas and materials, and secondary collection ensures the purity and yield of the product. Fluorine and nitrogen gas react with solid materials to generate corresponding fluorides, while reducing reaction time and improving reaction efficiency; achieving precise control of reaction temperature, reducing the risk of side reactions and improving product purity; reducing the probability of materials being carried to valves or pipelines by gas, reducing the economic consumption of equipment maintenance, and setting up a secondary collector to improve the yield of the reaction.

[0007] A method for preparing fluoride by reacting a solid material with fluorine gas specifically comprises the following steps:

[0008] First, the reactor is cleaned and dried, an inert solvent is added to the reactor, the agitator in the reactor is turned on and the solid material is added to ensure that the solid material is always in a dispersed state, which is more conducive to contact with the fluorine gas and thus improves the reaction efficiency. Nitrogen is then filled for tightness testing, and the reactor is heated. The fluorine and nitrogen gas are then controlled by a mass flow meter and passed through a gas disperser into the dispersion in the reactor (the dispersion refers to the dispersion obtained by dispersing the solid material in the inert solvent). The gas disperser can allow the fluorine and nitrogen gas to be passed into the reactor at a slow speed and in a more fully dispersed state, which greatly increases the contact probability and contact time between the fluorine and nitrogen gas and the solid material. The reactor pressure is maintained at 3-20KPa, the reaction time is 8-15h, the fluorine gas reacts with the solid material in the inert solvent, and the reaction heat released by the reaction can be partially absorbed by the solvent, thereby achieving better temperature control. To a certain extent, it can avoid the reaction temperature being too high due to the release of a large amount of heat due to too fast a reaction, causing the fluoride part of the solid material to decompose due to excessive temperature. At the same time, the remaining space at the top of the reactor can retain a certain amount of fluorine gas. For substances that react with fluorine gas to form low-fluoride compounds and then fluorinate to form high-fluoride compounds, high yields of corresponding fluoride compounds can be achieved. After the reaction is completed, the gas in the reactor is collected through primary and secondary condensation to obtain fluoride compounds.

[0009] Furthermore, the mesh size of the solid material is not less than 200 meshes; the solid material includes organic solid powder or non-metallic inorganic matter or metal powder.

[0010] Furthermore, the organic solid powder includes at least one of bisphenol A and uracil, the non-metallic inorganic substance includes at least one of arsenic, tellurium, and iodine, and the metal powder includes iridium.

[0011] Furthermore, the inert solvent includes one of a perfluoro solvent, a perfluoroalkylamine, a perfluorotripropylamine, a perfluoroalkane, a fluorinated aromatic hydrocarbon, and a fluorinated ionic liquid. The above-mentioned inert solvent refers to a solvent that has stable chemical properties and is not easy to react with reactants or products during the fluorination reaction.

[0012] Furthermore, the perfluoro solvent includes perfluoropolyether, the boiling point of which is greater than 200°C, and the boiling point depends on the molecular weight. The larger the molecular weight, the higher the boiling point. The perfluoroalkylamine includes perfluorobutyltriamine, the boiling point of which is 174°C. The boiling point of the perfluorotripropylamine is 155°C. The fluorinated ionic liquid includes 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, the boiling point of which is greater than 300°C.

[0013] Furthermore, nitrogen is filled in to conduct a tightness test. If the reactor pressure fluctuates within 1KPa within 1 hour, it proves that the reactor is well-sealed.

[0014] Furthermore, after nitrogen is filled in and a leak-tightness test is performed, the reactor is heated to 80-300° C., and the reaction temperature is lower than the boiling point of the inert solvent.

[0015] The reaction temperature with fluorine gas is not lower than 80° C. and not higher than 300° C., and the corresponding fluoride produced by the reaction is gaseous or solid at the reaction temperature.

[0016] Furthermore, after the reaction is completed, if the corresponding fluoride produced by the reaction is a solid at the reaction temperature, the step "the gas in the reactor is collected after primary condensation and secondary condensation to obtain fluoride" is replaced with "the solid in the reactor is filtered, washed, and dried to obtain fluoride".

[0017] Furthermore, the reactor uses monel or nickel material.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The reactor uses monel or nickel materials, significantly reducing the risk of fluorine gas corrosion. Fluorine and nitrogen gases pass through a gas disperser, dispersing the solid material into the solution. The synergistic effect of these two methods increases the probability of material contact with fluorine gas, facilitating the reaction. Furthermore, the reaction between the solid material and fluorine gas in an inert solvent effectively absorbs some of the reaction heat, preventing product decomposition due to excessive temperatures. Furthermore, external temperature control enables precise control of the reaction temperature. This prevents material from being carried into valves or pipes with the gas, causing blockages. This reduces the high reaction conditions placed on the entire device and equipment, laying a solid foundation for practical industrial production. DETAILED DESCRIPTION

[0020] In order to better understand the content of the present invention, the present invention will be further described below in conjunction with specific examples. The following examples are implemented based on the technology of the present invention and provide detailed implementation methods and operating steps, but the scope of protection of the present invention is not limited to the following examples.

[0021] 20% fluorine-nitrogen gas means that the volume fraction of fluorine gas in the fluorine-nitrogen gas is 20%.

[0022] Example 1:

[0023] First, the reactor is cleaned and dried. After 1 L of perfluoropolyether is added to the reactor, stirring is started and 100 g of arsenic powder is slowly added to the reactor to ensure that the arsenic powder is dispersed in the above 1 L of perfluoropolyether. The mesh size of the arsenic powder is 200 mesh. Then, nitrogen is filled into the reactor for a tightness test. If the pressure fluctuation range is within 1 KPa within 1 hour, it proves that the reactor is well sealed. If the test proves that the reactor is well sealed, the reactor temperature is heated to 100 ° C., and then 20% fluorine nitrogen gas is introduced. The flow rate of fluorine nitrogen is controlled by a mass flow meter and introduced into the arsenic powder and perfluoropolyether dispersion in the reactor through a gas disperser so that the reactor pressure is maintained at 3 KPa. The reaction time is 15 hours. After the reaction is completed, the gas in the reactor (including a mixture of product, fluorine, nitrogen and other fluorine compounds) is collected by primary condensation and secondary condensation to obtain arsenic pentafluoride.

[0024] In this example, 215.3 g of arsenic pentafluoride was obtained with a yield of 95% and a purity of 99.42%.

[0025] Example 2:

[0026] First, the reactor is cleaned and dried. After 0.5 L of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt is added to the reactor, stirring is started and 10 g of iridium powder is slowly added to the reactor to ensure that the iridium powder is dispersed in the above-mentioned 0.5 L of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt. The iridium powder has a mesh size of 250. Nitrogen is then filled for a tightness test. If the pressure fluctuation range is within 1 KPa within 1 hour, it proves that the reactor is well sealed. If the test proves that the reactor is well sealed, the reactor temperature is heated to 220 ° C., and then 20% fluorine nitrogen gas is introduced. The fluorine nitrogen gas is controlled by a mass flow meter and passed through a gas disperser into the iridium powder and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt dispersion in the reactor so that the reactor pressure is maintained at 8 KPa. The reaction time is 8 hours. After the reaction is completed, the gas in the reactor (including a mixture of product, fluorine gas, nitrogen and other fluorine compounds) is collected by primary condensation and secondary condensation to obtain iridium hexafluoride.

[0027] In this example, 15.45 g of iridium hexafluoride was obtained with a yield of 97% and a purity of 98.64%.

[0028] Example 3:

[0029] First, clean the reactor and dry it. After adding 1L of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt into the reactor, start stirring and slowly add 10g of tellurium powder into the reactor to ensure that the tellurium powder is dispersed in 1L of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt. The mesh size of the tellurium powder is 200 mesh. Then, fill it with nitrogen for a tightness test. If the pressure fluctuation range is within 1KPa within 1h, it proves that the reactor is well sealed. If the test proves that the reactor is well sealed, Then, the reactor temperature is heated to 220°C, and then 20% fluorine and nitrogen gas is introduced. The flow rate of the fluorine and nitrogen gas is controlled by a mass flow meter and introduced into the tellurium powder and 1-ethyl-3-methylimidazole bis(trifluoromethanesulfonyl)imide salt dispersion in the reactor through a gas disperser, so that the reactor pressure is maintained at 10KPa. The reaction time is 10h. After the reaction is completed, the gas in the reactor (including a mixture of product, fluorine, nitrogen and other fluorine compounds) is collected by primary condensation and secondary condensation to obtain tellurium hexafluoride.

[0030] In this example, 17.41 g of tellurium hexafluoride was obtained with a yield of 92% and a purity of 99.42%.

[0031] Example 4:

[0032] First, the reactor is cleaned and dried. After 1 L of perfluorotripropylamine is added to the reactor, stirring is started and 100 g of iodine is slowly added to the reactor to ensure that the iodine is dispersed in the above 1 L of perfluorotripropylamine. The iodine mesh size is 200 mesh. Then, nitrogen is filled for a tightness test. If the pressure fluctuation range is within 1 KPa within 1 hour, it proves that the reactor is well sealed. If the test proves that the reactor is well sealed, the reactor temperature is heated to 120 ° C., and then 20% fluorine nitrogen gas is introduced. The fluorine nitrogen gas is controlled by a mass flow meter and passed through a gas disperser into the iodine and perfluorotripropylamine dispersion in the reactor so that the reactor pressure is maintained at 6 KPa. The reaction time is 10 hours. After the reaction is completed, the gas in the reactor (including a mixture of product, fluorine gas, nitrogen and other fluorine compounds) is collected by primary condensation and secondary condensation to obtain iodine pentafluoride.

[0033] In this example, 173.1 g of iodine pentafluoride was obtained with a yield of 99% and a purity of 99.42%.

[0034] Comparative Example 1:

[0035] First, the reactor is cleaned and dried. After 1 L of acetonitrile is added to the reactor, stirring is started and 100 g of arsenic powder is slowly added to the reactor to ensure that the arsenic powder is dispersed in the above 1 L of acetonitrile. The mesh size of the arsenic powder is 200 mesh. Then, nitrogen is filled for a tightness test. If the pressure fluctuation range is within 1 KPa within 1 hour, it proves that the reactor is well sealed. If the test proves that the reactor is well sealed, the reactor temperature is heated to 100 ° C., and then 20% fluorine nitrogen gas is introduced. The flow rate of fluorine nitrogen is controlled by a mass flow meter and introduced into the arsenic powder and acetonitrile dispersion in the reactor through a gas disperser so that the reactor pressure is maintained at 3 KPa. The reaction time is 15 hours. After the reaction is completed, the gas in the reactor (including a mixture of product, fluorine, nitrogen and other fluorine compounds) is collected by primary condensation and secondary condensation to obtain arsenic pentafluoride.

[0036] In this comparative example, 167.8 g of arsenic pentafluoride was obtained with a yield of 74% and a purity of 90.2%.

[0037] Comparative Example 2:

[0038] First, the reactor is cleaned and dried. After 0.5L of dimethyl sulfoxide is added to the reactor, stirring is started and 10g of iridium powder is slowly added to the reactor to ensure that the iridium powder is dispersed in the above-mentioned 0.5L of dimethyl sulfoxide. The mesh number of the iridium powder is 250 mesh. Nitrogen is then filled for a tightness test. If the pressure fluctuation range is within 1Kpa within 1h, it proves that the reactor is well sealed. If the test proves that the reactor is well sealed, the reactor temperature is heated to 220°C, and then 20% fluorine nitrogen is introduced. The fluorine nitrogen is controlled by a mass flow meter and passed through a gas disperser into the iridium powder and dimethyl sulfoxide dispersion in the reactor so that the reactor pressure is maintained at 8Kpa. The reaction time is 8h. After the reaction is completed, the gas in the reactor (including a mixture of product, fluorine, nitrogen and other fluorine compounds) is collected by primary condensation and secondary condensation to obtain iridium hexafluoride.

[0039] In this comparative example, 5.09 g of iridium hexafluoride was obtained with a yield of 32% and a purity of 86.5%.

[0040] Comparative Example 3:

[0041] First, the reactor is cleaned and dried. After 1L of dimethyl sulfoxide is added to the reactor, stirring is started and 10g of tellurium powder is slowly added to the reactor to ensure that the tellurium powder is dispersed in the above 1L of dimethyl sulfoxide. The mesh size of the tellurium powder is 200 mesh. Then, nitrogen is filled for a tightness test. If the pressure fluctuation range is within 1KPa within 1h, it proves that the reactor is well sealed. If the test proves that the reactor is well sealed, the reactor temperature is heated to 220°C, and then 20% fluorine nitrogen gas is introduced. The fluorine nitrogen gas is controlled by a mass flow meter and passed through a gas disperser into the tellurium powder and dimethyl sulfoxide dispersion in the reactor so that the reactor pressure is maintained at 10KPa. The reaction time is 10h. After the reaction is completed, the gas in the reactor (including a mixture of product, fluorine, nitrogen and other fluorine compounds) is collected by primary condensation and secondary condensation to obtain tellurium hexafluoride.

[0042] In this comparative example, 7.75 g of tellurium hexafluoride was obtained with a yield of 41% and a purity of 92.4%.

[0043] Comparative Example 4:

[0044] First, the reactor is cleaned and dried. After 1L of carbon tetrachloride is added to the reactor, stirring is started and 100g of iodine is slowly added to the reactor to ensure that the iodine is dispersed in the above 1L of carbon tetrachloride. The iodine mesh size is 200 mesh. Then, nitrogen is filled into the reactor for a tightness test. If the pressure fluctuation range is within 1KPa within 1 hour, it proves that the reactor is well sealed. If the test proves that the reactor is well sealed, the reactor temperature is heated to 120°C, and then 20% fluorine nitrogen gas is introduced. The fluorine nitrogen gas is controlled by a mass flow meter and is introduced into the iodine and carbon tetrachloride dispersion in the reactor through a gas disperser so that the reactor pressure is maintained at 6KPa. The reaction time is 10 hours. After the reaction is completed, the gas in the reactor (including a mixture of product, fluorine gas, nitrogen and other fluorine compounds) is collected by primary condensation and secondary condensation to obtain iodine pentafluoride.

[0045] In this comparative example, 110.1 g of iodine pentafluoride was obtained with a yield of 63% and a purity of 82%.

[0046] Comparison of Examples 1-4 with Comparative Examples 1-4 shows that, under identical reaction conditions, the fluorination reaction using an inert solvent to disperse the solid material yields and purities significantly higher than that using a non-inert solvent system. This demonstrates that the method of the present invention is effective and advantageous for the fluorination of such solid materials.

[0047] The above description is merely an embodiment of the present invention and does not constitute any form of limitation to the present invention. The present invention may also have other forms of embodiments based on the above structures and functions, which are not listed here one by one. Therefore, any simple modification, equivalent changes, and modifications made to the above embodiments by any person skilled in the art in accordance with the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing fluoride by reacting a solid material with fluorine gas, characterized in that: The specific steps include: First, clean the reactor and dry it, add an inert solvent into the reactor, turn on the agitator in the reactor and add solid material to ensure that the solid material is in a dispersed state, then fill it with nitrogen for a tightness test, and then heat the reactor. Then, control the flow rate of fluorine nitrogen gas through a mass flow meter and pass it into the dispersion in the reactor through a gas disperser. The reactor pressure is maintained at 3-20KPa, and the reaction time is 8-15h. After the reaction is completed, the gas in the reactor is collected after primary condensation and secondary condensation to obtain fluoride.

2. The method for preparing fluoride by reacting a solid material with fluorine gas according to claim 1, characterized in that: The mesh number of the solid material is not less than 200 meshes; the solid material includes organic solid powder or non-metallic inorganic matter or metal powder.

3. The method for preparing fluoride by reacting a solid material with fluorine gas according to claim 2, characterized in that: The organic solid powder includes at least one of bisphenol A and uracil, the non-metallic inorganic substance includes at least one of arsenic, tellurium, and iodine, and the metal powder includes iridium.

4. The method for preparing fluoride by reacting a solid material with fluorine gas according to claim 1, wherein: The inert solvent includes one of perfluoro solvents, perfluoroalkylamines, perfluorotripropylamine, perfluoroalkanes, fluorinated aromatic hydrocarbons, and fluorinated ionic liquids.

5. The method for preparing fluoride by reacting a solid material with fluorine gas according to claim 4, characterized in that: Perfluoro solvents include perfluoropolyethers; perfluoroalkylamines include perfluorobutyltriamine; and fluorinated ionic liquids include 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

6. The method for preparing fluoride by reacting a solid material with fluorine gas according to claim 1, characterized in that: Fill the reactor with nitrogen for tightness test. If the reactor pressure fluctuates within 1KPa within 1 hour, it proves that the reactor is well-tightened.

7. The method for preparing fluoride by reacting a solid material with fluorine gas according to claim 1, characterized in that: The reactor uses monel or nickel material.

8. The method for preparing fluoride by reacting a solid material with fluorine gas according to claim 1, wherein: After filling with nitrogen and performing a tightness test, the reactor is heated to 80-300°C, and the reaction temperature is lower than the boiling point of the inert solvent.

9. The method for preparing fluoride by reacting a solid material with fluorine gas according to claim 1, wherein: After the reaction is completed, if the corresponding fluoride produced by the reaction is solid at the reaction temperature, the step "the gas in the reactor is collected after primary condensation and secondary condensation to obtain the fluoride" is replaced with "the solid in the reactor is filtered, washed, and dried to obtain the fluoride".