Preparation method of antimony pentafluoride

Abstract

The invention relates to a preparation method of antimony pentafluoride, which comprises the following steps: preheating raw material gas nitrogen trifluoride, placing nitrogen trifluoride and antimony powder in a tubular furnace reactor made of a specific material, carrying out gradient heating reaction at 300-400 DEG C under the condition that the antimony powder is distributed by adopting a multi-layer nickel plate tiled structure, carrying out reaction for 10-40 seconds, and carrying out solid filtration through a filter after the reaction is completed, so as to obtain the antimony pentafluoride. And carrying out cold trap collection to obtain an antimony pentafluoride product. The diameter of the reactor is made of a nickel material or Monel to prevent corrosion of antimony pentafluoride, the number of tiled layers of nickel plates is r / 5-r / 10, the contact area is increased, the reaction yield is increased, and the utilization rate of the raw material nitrogen trifluoride is increased.

Description

Technical Field

[0001] This invention belongs to the field of chemical process technology, specifically relating to a method for preparing antimony pentafluoride. Background Technology

[0002] Antimony pentafluoride (SbF5), as one of the strongest Lewis acids, holds an irreplaceable position in the field of fluorine chemistry. Its extremely strong fluoride ion affinity and excellent catalytic activity enable it to play a crucial role in petrochemicals, organic synthesis, the preparation of fluorinated electrolytes, and superacid systems (such as magic acid, HSO3F-SbF5). With the increasing demand for new energy materials and specialty fluorinated compounds, the industrial preparation technology of high-purity antimony pentafluoride has become a research hotspot.

[0003] Traditional methods for preparing antimony pentafluoride mainly include the following routes: (1) Direct fluorination method: using metallic antimony or antimony trifluoride as raw materials, reacting with fluorine gas (F2) at high temperature. Although this method is thorough, the high toxicity and strong corrosiveness of fluorine gas impose strict requirements on the sealing of equipment and operational safety, and by-products can easily lead to a decrease in product purity; (2) Halogen exchange method: using antimony pentachloride to react with anhydrous hydrogen fluoride, generating SbF5 through Cl / F replacement. This process requires excess HF and is accompanied by HCl by-products, the post-processing is complicated, and residual chlorine impurities can easily affect the performance of the catalyst; (3) Electrolysis method: electrolyzing an antimony-containing anode in a hydrofluoric acid system, the product purity is controllable but the energy consumption is high and it is difficult to scale up.

[0004] Current technologies face three major bottlenecks: First, the conflict between raw material costs and hazards is prominent; the fluorine process relies on specialized equipment, while the HF process requires the treatment of corrosive waste liquids. Second, product separation and purification are difficult, especially since trace amounts of moisture can hydrolyze to generate impurities such as SbOF3. Third, the reaction conditions are harsh, typically requiring 200-300℃, which easily leads to antimony volatilization losses and reactor coking. Although recent studies have attempted to improve reaction selectivity using SbF3-Cl2-F2 stepwise fluorination or ionic liquid media, problems such as complex processes or catalyst deactivation still exist. Summary of the Invention

[0005] The purpose of this invention is to provide a mild and controllable method for preparing antimony pentafluoride, which avoids hazards by changing the raw materials while achieving a high conversion rate.

[0006] The technical solution of the present invention:

[0007] A method for preparing antimony pentafluoride includes the following steps: preheating nitrogen trifluoride, distributing antimony powder in a tubular furnace reactor using a multi-layer nickel plate flat-lay structure, introducing preheated nitrogen trifluoride into the tubular furnace reactor, and reacting at 300-400℃.

[0008] Preferably, the preheating temperature is 100-250℃.

[0009] Preferably, the tubular furnace reactor is made of nickel or Monel, and the molar ratio of nitrogen trifluoride to antimony powder is 5:3.

[0010] Preferably, the number of nickel plate layers in the nickel plate flat-lay structure is r / 5-r / 10, where r is the diameter of the tubular furnace reactor pipe, in mm.

[0011] Preferably, the reaction temperature adopts a gradient heating mode, with a 50°C increase followed by a 20-minute dwell time, and the gradient heating rate is 5-10°C / min.

[0012] Preferably, the reaction time is 10s-40s.

[0013] Preferably, a porous filter is added to the rear section of the tubular furnace reactor;

[0014] The reaction temperature is 320-370℃, and the gradient heating rate is 5-8℃ / min.

[0015] Preferably, the preheating temperature is 200-250℃.

[0016] Preferably, the number of nickel plate layers in the nickel plate flat-lay structure is r / 8-r / 10, where r is the diameter of the tubular furnace reactor pipe, in mm.

[0017] Preferably, the reaction time is 20s-35s.

[0018] Innovations and benefits of this invention:

[0019] This invention reduces the danger of fluorine gas by replacing the reaction raw material with nitrogen trifluoride. At the same time, multiple layers of plates are added inside the reactor to increase the contact area, prevent the antimony powder raw material from being accumulated and covered, improve the conversion rate, and reduce the content of by-products from raw material accumulation.

[0020] The method of this invention is expected to solve the problem of balancing efficiency and safety in industrial production using existing methods, and provide technical support for the supply of high-end fluorinated materials. Detailed Implementation

[0021] Example 1:

[0022] A method for preparing antimony pentafluoride, wherein nitrogen trifluoride is first preheated in a preheater at a temperature of 250°C.

[0023] Using a nickel tube furnace reactor with a diameter of 80 mm, 1 kg of antimony powder was spread evenly on a multi-layer plate support with 16 layers. Nitrogen trifluoride gas was introduced and the residence time was 40 s. The temperature was increased by gradient at 8 ℃ / min, with each increase of 50 ℃ followed by a residence time of 20 min. The reaction temperature was 300 ℃.

[0024] Final yield of antimony pentafluoride: CH3F = 90.5%, purity 95%.

[0025] Example 2:

[0026] A method for preparing antimony pentafluoride, wherein nitrogen trifluoride is first preheated in a preheater at a preheating temperature of 100°C.

[0027] Using a nickel tube furnace reactor with a diameter of 80 mm, 1 kg of antimony powder was spread evenly on a multi-layer plate support with 8 layers. Nitrogen trifluoride gas was introduced, with a residence time of 10 s. The temperature was increased by a gradient of 10 ℃ / min, with each increase being 50 ℃, and the residence time was 20 min. The reaction temperature was 400 ℃.

[0028] Final yield of antimony pentafluoride: CH3F = 85.5%, purity 96%.

[0029] Example 3:

[0030] A method for preparing antimony pentafluoride, wherein nitrogen trifluoride is first preheated in a preheater at a preheating temperature of 200°C.

[0031] Using a nickel tube furnace reactor with a diameter of 80 mm, 1 kg of antimony powder was spread evenly on a multi-layer plate support with 10 layers. Nitrogen trifluoride gas was introduced, the residence time was 35 s, the temperature was increased by gradient of 5℃ / min, and the residence time was 20 min for each 50℃ increase. The reaction temperature was 320℃.

[0032] Final yield of antimony pentafluoride: CH3F = 93.4%, purity 96.5%.

[0033] Example 4:

[0034] A method for preparing antimony pentafluoride, wherein nitrogen trifluoride is first preheated in a preheater at a preheating temperature of 200°C.

[0035] Using an 80mm diameter Monel tubular furnace reactor pipe, 1kg of antimony powder was spread evenly on a multi-layer plate support with 10 layers. Nitrogen trifluoride gas was introduced, with a residence time of 20s. The temperature was increased by a gradient of 5℃ / min, with each increase of 50℃ lasting for 20min. The reaction temperature was 370℃.

[0036] Final yield of antimony pentafluoride: CH3F = 92.8%, purity 96%.

[0037] Example 5:

[0038] A method for preparing antimony pentafluoride, wherein nitrogen trifluoride is first preheated in a preheater at a preheating temperature of 200°C.

[0039] Using an 80mm diameter Monel tubular furnace reactor pipe, 1kg of antimony powder was spread evenly on a multi-layer plate support with 10 layers. Nitrogen trifluoride gas was introduced, with a residence time of 30s. The temperature was increased by a gradient of 5℃ / min, with each increase of 50℃ followed by a residence time of 20min. The reaction temperature was 350℃.

[0040] The final yield of antimony pentafluoride was CH3F = 96.18%, with a purity of 97%.

[0041] Comparative Example 1:

[0042] The difference between this comparative example and Example 1 is that nitrogen trifluoride is not preheated;

[0043] Final yield of antimony pentafluoride: CH3F = 20%, purity 10%.

[0044] Comparative Example 2:

[0045] The difference between this comparative example and Example 1 is that the plate support uses a single layer;

[0046] Final yield of antimony pentafluoride: CH3F = 33%, purity 14%.

[0047] Comparative Example 3:

[0048] The difference between this comparative example and Example 1 is that: instead of gradient heating, the temperature is directly raised to the reaction temperature;

[0049] The final yield of antimony pentafluoride was CH3F = 40%, with a purity of 35%. The reaction was violent, with the temperature rising rapidly to 400℃. This poses significant safety risks.

[0050] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process for the preparation of antimony pentafluoride, characterized in that, The method comprises the following steps: preheating nitrogen trifluoride, laying antimony powder in a multi-layer nickel plate paving structure in a tubular furnace reactor, introducing the preheated nitrogen trifluoride into the tubular furnace reactor, and reacting at 300-400 DEG C.

2. A process for the preparation of antimony pentafluoride as claimed in claim 1, wherein, The preheating temperature is 100-250 DEG C.

3. The method for preparing antimony pentafluoride as described in claim 1, characterized in that, The tubular furnace reactor is made of nickel or Monel, and the molar ratio of the nitrogen trifluoride to the antimony powder is 5:

3.

4. The method for preparing antimony pentafluoride as described in claim 1, characterized in that, The number of layers of the nickel plate in the nickel plate paving structure is r / 5-r / 10, and r is the diameter of the tubular furnace reactor pipeline, in mm.

5. The method for preparing antimony pentafluoride as described in claim 1, characterized in that, The reaction temperature is in a gradient heating mode, 50 DEG C per time, 20 min per stop, and the gradient heating rate is 5-10 DEG C / min.

6. The method for preparing antimony pentafluoride as described in claim 1, characterized in that, The reaction time is 10 s-40 s.

7. A process for the preparation of antimony pentafluoride as claimed in claim 5 wherein, A porous filter is added to the rear section of the tubular furnace reactor. The reaction temperature is 320-370 DEG C, and the gradient heating rate is 5-8 DEG C / min.

8. The method for preparing antimony pentafluoride as described in claim 2, characterized in that, The preheating temperature is 200-250 DEG C.

9. The method for preparing antimony pentafluoride as described in claim 4, characterized in that, The number of layers of the nickel plate in the nickel plate paving structure is r / 8-r / 10, and r is the diameter of the tubular furnace reactor pipeline, in mm.

10. The method for preparing antimony pentafluoride as described in claim 6, characterized in that, The reaction time is 20 s-35 s.