Adsorbent suitable for purifying thionyl chloride and purification method

Abstract

The present invention provides an adsorbent suitable for purifying thionyl chloride. The preparation method of the adsorbent includes dispersing boehmite powder in water, adding citric acid, heating and stirring, filtering and vacuum drying; impregnating zeolite powder in an aluminum chloride solution, then filtering and introducing sulfur dioxide and hydrogen sulfide gases at 35-40 °C; mixing the treated boehmite powder, zeolite powder with pseudo-boehmite and water, and extruding to obtain the adsorbent. The adsorbent of the present invention can conveniently reduce the content of sulfuryl chloride and iron ions in the thionyl chloride product, and is easy to separate from the product.

Description

Technical Field

[0001] The present invention relates to the field of thionyl chloride production, and more specifically, to an adsorbent suitable for purifying thionyl chloride and a purification method thereof. Background Art

[0002] Thionyl chloride is a colorless or yellow liquid inorganic compound with a strong pungent odor. It is miscible with organic solvents such as benzene, chloroform, and carbon tetrachloride. It hydrolyzes in the presence of water and decomposes upon heating. It is mainly used for manufacturing acyl chlorides and is also used in the production of pesticides, pharmaceuticals, dyes, etc. In recent years, with the development of new energy vehicle technology, it has been found that thionyl chloride can be used as a raw material for the solute of power lithium battery electrolytes.

[0003] Currently, domestic enterprises generally use the sulfur dioxide gas phase method to produce thionyl chloride. In the production process of this method, it is inevitable to produce sulfuryl chloride. The boiling point of thionyl chloride (78.8 °C) is very close to that of sulfuryl chloride (69 °C). Conventional distillation methods are difficult to completely separate thionyl chloride and sulfuryl chloride, and the content of sulfuryl chloride in the product remains high. Patent US4337235A decomposes sulfuryl chloride by adding sulfur and the catalyst aluminum trichloride. The method includes fractionating the mixture in the presence of sulfur to distill a mixture of thionyl chloride, sulfuryl chloride, sulfur dichloride, and sulfur. The distillate passes through sulfur-aluminum chloride particles and reflux vapor containing sulfur-aluminum chloride in a vapor state to convert sulfuryl chloride into sulfur dioxide, chlorine, and sulfur monochloride. However, the method of this patent requires adding sulfur and the catalyst aluminum trichloride separately in different steps, which is troublesome to operate. Moreover, sulfur dissolves very slowly, and the separation effect after use is not ideal.

[0004] Patent CN103172031B provides a method for refining thionyl chloride using special equipment. In this method, the saturated steam raw material enters the heater and is heated into superheated gas inside the heater. The superheated gas enters the fixed-bed reactor and undergoes a decomposition reaction when contacting the activated carbon bed layer inside the fixed-bed reactor. The gas after the reaction enters the cooler and is cooled into a saturated liquid, and then enters the distillation column. Gas-liquid mass transfer occurs in the column. Thionyl chloride, sulfur dioxide, and chlorine are taken out from the top of the column, and high-purity thionyl chloride product is taken out from the bottom of the column. The purity of thionyl chloride is above 99.7%, and the content of thionyl chloride is less than 0.3%. However, if this method is to be used, new equipment must be replaced or added. For enterprises with insufficient funds for equipment investment, it is not convenient to directly match the original device for use, and the general applicability is not strong.

[0005] In addition to the high content of thionyl chloride in domestic thionyl chloride, the iron ion content is much higher than that of imported foreign products because the synthesis system is generally made of stainless steel, resulting in a significant gap in the quality between domestic thionyl chloride and imported foreign products, making it difficult to replace and apply it in the new energy battery field.

[0006] At present, there is no convenient solution disclosed that can simultaneously and conveniently reduce the content of sulfuryl chloride and iron ions in thionyl chloride products. In view of this, the present application is specifically proposed. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides an adsorbent suitable for purifying thionyl chloride.

[0008] An embodiment of the present invention provides an adsorbent suitable for purifying thionyl chloride. The preparation method of the adsorbent includes the following steps:

[0009] (1) Disperse boehmite powder in water, add citric acid, heat and stir, filter, and vacuum dry;

[0010] (2) Immerse zeolite powder in aluminum chloride solution, then filter, and introduce sulfur dioxide and hydrogen sulfide gases at 35 - 40 °C;

[0011] (3) Mix the boehmite powder treated in step (1), the zeolite powder treated in step (2) with pseudoboehmite and water, and extrude into shape to obtain the adsorbent.

[0012] As an example, in step (1), the molar ratio of boehmite powder to citric acid is 1:0.4 - 1.2.

[0013] As an example, in step (1), the temperature of heating and stirring is 80 - 95 °C, and the time is 15 - 32 h.

[0014] As an example, in step (2), the mass of aluminum chloride in the aluminum chloride solution is 0.05% - 2.8% of the mass of the zeolite powder.

[0015] As an example, in step (2), the molar ratio of sulfur dioxide to hydrogen sulfide gas is 1:2.0 - 2.2.

[0016] As an example, calculated based on every 1000 g of zeolite powder, the rate of introducing sulfur dioxide and hydrogen sulfide gases is 2 - 6 L / h, and the time is 0.5 - 5.5 h.

[0017] As an example, the mass ratio of boehmite powder, zeolite powder and pseudoboehmite is 3 - 5:5 - 7:0.5 - 1.5.

[0018] The present invention also provides a method for purifying thionyl chloride. After the crude thionyl chloride is subjected to adsorption treatment using the adsorbent according to any one of the above, distillation is then carried out to obtain a purified thionyl chloride product.

[0019] The present invention has the following advantages compared with the prior art:

[0020] 1. The present invention provides an adsorbent that can simultaneously reduce the content of sulfuryl chloride and iron ions in the crude thionyl chloride product, and the adsorbent is easy to separate from the product after use.

[0021] 2. The adsorbent of the present invention is conducive to industrial promotion and use, and thionyl chloride production enterprises do not need to add additional equipment.

[0022] 3. The adsorbent of the present invention will not introduce other impurities into the thionyl chloride product.

[0023] 4. The adsorbent of the present invention is prepared from cheap and easily available raw materials, and has a low cost. Detailed Embodiments

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] In the following embodiments, the raw materials used are all ordinary products purchased from the market, and the manufacturers or batches do not affect the achievement of the basic beneficial effects of the technical solutions of the present invention.

[0026] In the specific implementation process, the adsorbent suitable for purifying thionyl chloride of the present invention can be formed into common solid adsorbent shapes such as spherical particles and long strips.

[0027] As a specific example, spherical particles with an average particle size of 2.5 - 4 mm are used in the following cases.

[0028] In the present invention, vacuum drying can be carried out using existing conventional vacuum drying equipment. The temperature of vacuum drying is controlled at 64 - 68 °C, and the vacuum degree is controlled at 0.07 - 0.08 MPa.

[0029] Example 1

[0030] An adsorbent suitable for purifying thionyl chloride, the preparation method includes the following steps:

[0031] (1) Disperse 1000 g of boehmite powder in 3 L of water, add 1281.1 g of citric acid, heat to 85 °C, stir for 20 h, filter, and vacuum dry;

[0032] (2) Dissolve 0.5 g of aluminum chloride in 2 L of water to obtain an aluminum chloride solution; immerse 1000 g of zeolite powder in the aluminum chloride solution, then filter and pass sulfur dioxide and hydrogen sulfide gases at 40°C; among them, the volume ratio of sulfur dioxide to hydrogen sulfide gas is 1:2, the ventilation rate is 2 L / h, and the time is 5.5 h;

[0033] (3) Mix the boehmite powder treated in step (1), the zeolite powder treated in step (2) with 100 g of pseudo-boehmite and water (an appropriate amount, not limited to a specific dosage, just convenient for forming), and extrude to form the adsorbent.

[0034] Example 2

[0035] An adsorbent suitable for purifying thionyl chloride, and the preparation method includes the following steps:

[0036] (1) Disperse 428.6 g of boehmite powder in 3 L of water, add 1674.2 g of citric acid, heat to 95°C and stir for 15 h, filter and vacuum dry;

[0037] (2) Take 28 g of aluminum chloride and dissolve it in 2 L of water to obtain an aluminum chloride solution; immerse 1000 g of zeolite powder in the aluminum chloride solution, then filter and pass sulfur dioxide and hydrogen sulfide gases at 35°C; among them, the volume ratio of sulfur dioxide to hydrogen sulfide gas is 1:2.1, the ventilation rate is 6 L / h, and the time is 0.5 h;

[0038] (3) Mix the boehmite powder treated in step (1), the zeolite powder treated in step (2) with 214.3 g of pseudo-boehmite and water (an appropriate amount is fine), and extrude to form the adsorbent.

[0039] Example 3

[0040] An adsorbent suitable for purifying thionyl chloride, and the preparation method includes the following steps:

[0041] (1) Disperse 666.7 g of boehmite powder in 3 L of water, add 1423.7 g of citric acid, heat to 90°C and stir for 25 h, filter and vacuum dry;

[0042] (2) Take 1 g of aluminum chloride and dissolve it in 2 L of water to obtain an aluminum chloride solution; immerse 1000 g of zeolite powder in the aluminum chloride solution, then filter and pass sulfur dioxide and hydrogen sulfide gases at 38°C; among them, the volume ratio of sulfur dioxide to hydrogen sulfide gas is 1:2.2, the ventilation rate is 5 L / h, and the time is 4 h;

[0043] (3) Mix the boehmite powder treated in step (1), the zeolite powder treated in step (2) with 166.7 g of pseudo-boehmite and water (an appropriate amount is fine), and extrude to form the adsorbent.

[0044] Example 4

[0045] An adsorbent suitable for purifying thionyl chloride, and the preparation method includes the following steps:

[0046] (1) Disperse 1000 g of boehmite powder in 3 L of water, add 2668.7 g of citric acid, heat to 80 °C and stir for 20 h, filter and vacuum dry;

[0047] (2) Take 10 g of aluminum chloride and dissolve it in 2 L of water to obtain an aluminum chloride solution; immerse 1000 g of zeolite powder in the aluminum chloride solution, then filter and pass sulfur dioxide and hydrogen sulfide gases at 35 - 40 °C; wherein, the volume ratio of sulfur dioxide to hydrogen sulfide gases is 1:2, the ventilation rate is 4 L / h, and the time is 5 h;

[0048] (3) Mix the boehmite powder treated in step (1), the zeolite powder treated in step (2) with 240 g of pseudoboehmite and water (appropriate amount is fine), and extrude into shape to obtain the adsorbent.

[0049] Example 5

[0050] An adsorbent suitable for purifying thionyl chloride, and the preparation method includes the following steps:

[0051] (1) Disperse 666.7 g of boehmite powder in 3 L of water, add 2562.2 g of citric acid, heat to 90 °C and stir for 18 h, filter and vacuum dry;

[0052] (2) Take 20 g of aluminum chloride and dissolve it in 2 L of water to obtain an aluminum chloride solution; immerse 1000 g of zeolite powder in the aluminum chloride solution, then filter and pass sulfur dioxide and hydrogen sulfide gases at 40 °C; wherein, the volume ratio of sulfur dioxide to hydrogen sulfide gases is 1:2.1, the ventilation rate is 6 L / h, and the time is 2 h;

[0053] (3) Mix the boehmite powder treated in step (1), the zeolite powder treated in step (2) with 250 g of pseudoboehmite and water (appropriate amount is fine), and extrude into shape to obtain the adsorbent.

[0054] Example 6

[0055] An adsorbent suitable for purifying thionyl chloride, and the preparation method includes the following steps:

[0056] (1) Disperse 428.6 g of boehmite powder in 3 L of water, add 1464.2 g of citric acid, heat to 80 °C and stir for 28 h, filter and vacuum dry;

[0057] (2) Dissolve 25 g of aluminum chloride in 2 L of water to obtain an aluminum chloride solution; immerse 1000 g of zeolite powder in the aluminum chloride solution, then filter and pass sulfur dioxide and hydrogen sulfide gases at 37°C; among them, the volume ratio of sulfur dioxide to hydrogen sulfide gas is 1:2, the gas passing rate is 3 L / h, and the time is 3.5 h;

[0058] (3) Mix the boehmite powder treated in step (1), the zeolite powder treated in step (2) with 142.9 g of pseudo-boehmite and water (an appropriate amount is sufficient), and extrude to form the adsorbent.

[0059] Comparative Example 1

[0060] The difference from Example 1 is that the zeolite powder is replaced with activated carbon of the same mass, and the others remain the same.

[0061] Comparative Example 2

[0062] The difference from Example 1 is that the boehmite powder is replaced with zeolite powder + activated carbon of the same mass (mass ratio 1:1), and the others remain the same.

[0063] Comparative Example 3

[0064] The difference from Example 1 is that in step (2), it is directly mixed with the solid sulfur theoretically corresponding to the introduced gas in an equal amount, and the others remain the same.

[0065] Effect Example

[0066] Use the adsorbents obtained from the above Examples 1-6 and Comparative Examples 1-3 to pretreat the same batch of crude thionyl chloride from a certain factory, and investigate their pre-purification performance.

[0067] The crude thionyl chloride to be treated is slightly yellow, the content of thionyl chloride is 95 w%, the content of sulfuryl chloride is 4 w%, and the balance is other impurities, among which the iron ion content is 15.62×10 -6 .

[0068] Put it into use according to the mass ratio of adsorbent: crude thionyl chloride of 1:5, stir at 40°C for 12 h, filter to remove the adsorbent, and obtain the treated thionyl chloride. The color, the content of sulfuryl chloride and iron ions of the pretreated crude thionyl chloride are shown in Table 1 below.

[0069] In this effect example, the methods for testing the components of the crude product and the pretreated crude product are the conventional methods in the industry under the same test conditions (refer to HG / T 3788-2005). It is only used to assist in reflecting the advantages of the present invention and is not the innovative point of the present invention, so it will not be elaborated.

[0070] Table 1

[0071] Use adsorbent Color Thionyl chloride (%) Sulfuryl chloride (%) Iron ion content Example 1 Colorless 96.49 2.73 <![CDATA[10.42×10 -6 > Example 2 Colorless 96.58 2.56 <![CDATA[9.81×10- 6 > Example 3 Colorless 96.70 2.41 <![CDATA[9.29×10- 6 > Example 4 Colorless 96.62 2.53 <![CDATA[9.75×10- 6 > Example 5 Colorless 96.68 2.40 <![CDATA[9.33×10- 6 > Example 6 Colorless 96.77 2.32 <![CDATA[9.26×10- 6 > Comparative Example 1 Slightly lighter yellow 95.11 3.95 <![CDATA[15.58×10 -6 > Comparative Example 2 Slightly lighter yellow 95.09 3.98 <![CDATA[15.63×10 -6 <!-- 4 -->]]> Comparative Example 3 Nearly colorless 95.74 3.47 <![CDATA[13.74×10 -6 >

[0072] As can be seen from the experimental results in the above table, the adsorbent of the present invention helps to pre-purify the crude thionyl chloride, reduce the contents of sulfuryl chloride and iron ions, and relieve the burden on the subsequent distillation process.

[0073] In addition, according to the feedback from an enterprise that has tried the adsorbent of the present invention, after pre-treating with the adsorbent of the present invention on the existing thionyl chloride production line and then through the existing conventional distillation operation, the purity of the purified thionyl chloride product obtained can reach 99.81%, the content of sulfuryl chloride is less than 0.22%, and the content of iron ions can be as low as 3.15×10 -6 , which is a big step closer to replacing imported products in the application in the battery field.

[0074] Although the embodiments disclosed in the present invention are as above, the above content is only the embodiments adopted for the convenience of understanding the present invention and is not used to limit the present invention. Any person skilled in the art within the scope of the present invention can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed by the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. An adsorbent suitable for purifying thionyl chloride, and the preparation method of the adsorbent comprises the following steps: (1) Disperse boehmite powder in water, add citric acid, heat and stir, filter and vacuum dry; (2) Immerse zeolite powder in aluminum chloride solution, then filter, and introduce sulfur dioxide and hydrogen sulfide gases at 35 - 40 °C; (3) Mix the boehmite powder treated in step (1), the zeolite powder treated in step (2) with pseudo-boehmite and water, and extrude into shape to obtain the adsorbent; Among them, In step (2), the mass of aluminum chloride in the aluminum chloride solution is 0.05% - 2.8% of the mass of the zeolite powder.

2. The adsorbent suitable for purifying thionyl chloride according to claim 1, characterized in that, In step (1), the molar ratio of boehmite powder to citric acid is 1:0.4 - 1.

2.

3. The adsorbent suitable for purifying thionyl chloride according to claim 1, characterized in that, In step (1), the temperature of heating and stirring is 80 - 95 °C, and the time is 15 - 32 h.

4. The adsorbent suitable for purifying thionyl chloride according to claim 1, wherein In step (2), the molar ratio of sulfur dioxide to hydrogen sulfide gas is 1:2.0 - 2.

2.

5. The adsorbent suitable for purifying thionyl chloride according to claim 4, wherein, Calculated by every 1000 g of zeolite powder, the rate of introducing sulfur dioxide and hydrogen sulfide gases is 2 - 6 L / h, and the time is 0.5 - 5.5 h.

6. The adsorbent suitable for purifying thionyl chloride according to claim 1, characterized in that, The mass ratio of boehmite powder, zeolite powder and pseudo-boehmite is 3 - 5:5 - 7:0.5 - 1.

5.

7. A method for purifying thionyl chloride, characterized in that, After the crude product of thionyl chloride is subjected to adsorption treatment by using the adsorbent according to any one of claims 1 - 6, and then distilled, a purified thionyl chloride product is obtained.