A method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination

Abstract

The invention discloses a method for synthesizing trifluoromethyl sulfide by continuous chlorination, wherein bis(trifluoromethyl) disulfide and chlorine are continuously reacted in a fixed bed reactor equipped with a catalyst to generate trifluoromethyl sulfide. The reaction is carried out in a fixed bed reactor, with few side reactions, high purity and high yield, and the yield is above 95%.

Description

Technical Field

[0001] The invention relates to a method for synthesizing trifluoromethyl sulfonyl chloride, in particular to a method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination. Background Art

[0002] Trifluoromethyl sulfoxide is an important chemical intermediate and plays an important role in materials and other industries.

[0003] At present, the preparation methods of trifluoromethyl sulfonyl chloride are mainly as follows: US5087747A discloses a synthesis method of trifluoromethyl sulfonyl chloride, that is, it is prepared by reacting bis(trifluoromethyl) disulfide and chlorine in a strong acid environment. The reaction will produce a large amount of waste acid, which is cumbersome and difficult to post-process and has high processing costs. The boiling point of trifluoromethyl sulfonyl chloride is 0-3°C, and there is chlorine in the system, making it difficult to recover the product. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination. The reaction is carried out in a fixed bed reactor, with few side reactions, high purity and high yield, which is above 95%.

[0005] The present invention is achieved through the following technical solutions:

[0006] The invention provides a method for synthesizing trifluoromethyl sulfide chloride by continuous chlorination. Bis(trifluoromethyl) disulfide and chlorine gas are continuously reacted in a fixed bed reactor equipped with a catalyst to generate trifluoromethyl sulfide chloride.

[0007] Preferably, the material enters the fixed bed reactor in gaseous form. The gaseous material fully contacts the solid catalyst, increasing the material contact area and improving the reaction rate.

[0008] The reaction formula is:

[0009] .

[0010] In the above method, the fixed bed reactor can adopt commonly used axial, radial, and shell-and-tube reactors.

[0011] In the above method, the catalyst is activated carbon, resin, molecular sieve, etc., preferably activated carbon. The catalyst catalyzes the reaction of reactants on the surface of the solid catalyst to reduce the occurrence of side reactions.

[0012] In the above method, the molar ratio of bis(trifluoromethyl)disulfide to chlorine is 1:1-5, preferably 1:1-3.

[0013] In the above method, the reaction temperature is 0-150°C and the pressure is 0-0.5MPa. Preferably, the reaction temperature is 20-100°C, more preferably 50-80°C, and most preferably 50-60°C. The present invention can achieve a good yield at a temperature of 50-80°C.

[0014] In the above method, the specific reaction includes the following steps: bis(trifluoromethyl) disulfide and chlorine are continuously reacted in a fixed bed reactor equipped with a catalyst to generate trifluoromethyl chlorine sulfide, and excess chlorine enters liquid alkali for absorption, which can be recycled in industrial equipment.

[0015] In the above method, the product trifluoromethyl sulfhydryl chloride obtained by the reaction has a boiling point of about 0-3°C and can be liquefied and collected by condensation at -15°C.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The present invention uses bis(trifluoromethyl) disulfide and chlorine as raw materials, does not use strong acid, and is beneficial to environmental protection.

[0018] 2. The present invention carries out catalytic reaction in a fixed bed, and the catalyst is activated carbon, resin, molecular sieve, etc., which reacts on the solid surface to reduce the occurrence of side reactions.

[0019] 3. The present invention utilizes bis(trifluoromethyl) disulfide and chlorine to catalyze the reaction and directly obtain high-purity trifluoromethyl sulfide with a yield of more than 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the spectrum of trifluoromethylsulfonyl chloride prepared in Example 1. DETAILED DESCRIPTION

[0021] The present invention is further described below by specific examples, which are exemplary only and are not intended to limit the content. In the following examples, unless otherwise specified, all reagents used can be purchased from the market. In the following examples, the terms not described in detail have the meanings reported in the prior art, and the operations and methods not described in detail can all refer to the operations of the prior art. The specifications of the fixed beds selected in the following examples are the same.

[0022] The treatment method of activated carbon is as follows: the activated carbon is columnar activated carbon with a diameter of 2.5mm, and is pretreated to remove the metal ions therein. The method is to soak it in dilute hydrochloric acid for 6 hours, then replace it with deionized water to neutrality, and then dry it for use.

[0023] Molecular sieve catalyst: Any molecular sieve catalyst that can achieve catalytic reaction can be used. H-type molecular sieve is preferred. Titanium-silicon-aluminum molecular sieve can also be selected, selected from at least one of titanium-silicon-aluminum molecular sieve with MFI structure, titanium-silicon-aluminum molecular sieve with MEL structure, titanium-silicon-aluminum molecular sieve with BEA structure, titanium-silicon-aluminum molecular sieve with MWW structure, titanium-silicon-aluminum molecular sieve with MOR structure, titanium-silicon-aluminum molecular sieve with TUN structure and titanium-silicon-aluminum molecular sieve with two-dimensional hexagonal structure.

[0024] Resin catalyst: also called polymer porous microspheres, any porous microspheres that can achieve catalytic reactions can be used.

[0025] The fixed bed reactor can adopt commonly used axial, radial, and shell-and-tube reactors, all of which can realize the reaction.

[0026] Example 1

[0027] In a fixed bed reactor equipped with activated carbon (the fixed bed has a diameter of 15 mm, a length of 1 m, and is filled with activated carbon catalyst), bis(trifluoromethyl) disulfide and chlorine enter from the lower part of the fixed bed, the bottom of the tower and the fixed bed are heated, the temperature is set to 60°C, the pressure is normal pressure, and the material enters the bed in gaseous form for reaction. The reaction product passes through the bed, and the product enters two-stage condensation and liquefaction to obtain the product. Excess chlorine enters the liquid alkali for absorption. The reaction is carried out with a mass of 202g of bis(trifluoromethyl) disulfide and 106.5g of chlorine, and 271g of product is obtained, with a content of 99.10% and a yield of 98.37%. The spectrum of trifluoromethyl sulfhydryl prepared in Example 1 is shown in Figure 1 .

[0028] Example 2

[0029] In a fixed bed reactor equipped with activated carbon (the fixed bed has a diameter of 15 mm, a length of 1 m, and is filled with activated carbon catalyst), bis(trifluoromethyl) disulfide and chlorine enter from the bottom of the fixed bed, the tower bottom and the fixed bed are heated, the temperature is set to 60°C, the pressure is normal pressure, and the material enters the bed in gaseous form for reaction. The reaction product passes through the bed, and the product enters two-stage condensation and liquefaction to obtain the product. Excess chlorine enters the liquid alkali for absorption. The reaction is conducted with a mass of 202g of bis(trifluoromethyl) disulfide and 142g of chlorine, and a product of 271.11g is obtained, with a content of 99.22% and a yield of 98.53%.

[0030] Example 3

[0031] The other conditions were the same as those in Example 1, except that: bis(trifluoromethyl) disulfide and chlorine (molar ratio was 1:3, temperature was 60°C, pressure was normal pressure, 202 g of bis(trifluoromethyl) disulfide and 213 g of chlorine were fed into the reaction, and 271.68 g of product was obtained, with a content of 99.19% and a yield of 98.71%.

[0032] Example 4

[0033] The other conditions are the same as those in Example 1, except that the molar ratio of bis(trifluoromethyl) disulfide and chlorine is 1:1.5, the temperature is 20°C, the pressure is 0.2 MPa, 202 g of bis(trifluoromethyl) disulfide and 106.5 g of chlorine are fed into the reaction, and 269.99 g of the product is obtained, with a content of 98.73% and a yield of 97.64%.

[0034] Example 5

[0035] The other conditions are the same as those in Example 1, except that the molar ratio of bis(trifluoromethyl) disulfide and chlorine is 1:1.5, the temperature is 60° C., the pressure is 0.2 MPa, 202 g of bis(trifluoromethyl) disulfide and 106.5 g of chlorine are fed into the reaction, and 270.23 g of the product is obtained, with a content of 98.99% and a yield of 97.99%.

[0036] Example 6

[0037] The other conditions were the same as those in Example 1, except that the molar ratio of bis(trifluoromethyl) disulfide and chlorine was 1:1.5, the temperature was 80°C, the pressure was 0.3 MPa, 202 g of bis(trifluoromethyl) disulfide and 106.5 g of chlorine were fed into the reaction, and 270.32 g of the product was obtained, with a content of 99.11% and a yield of 98.14%.

[0038] Example 7

[0039] The other conditions were the same as those in Example 1, except that the molar ratio of bis(trifluoromethyl) disulfide and chlorine was 1:1.5, the temperature was 100° C., the pressure was 0.35 MPa, 202 g of bis(trifluoromethyl) disulfide and 106.5 g of chlorine were fed into the reaction, and 270.65 g of the product was obtained, with a content of 98.98% and a yield of 98.13%.

[0040] Example 8

[0041] The other conditions were the same as those in Example 1, except that the molar ratio of bis(trifluoromethyl) disulfide and chlorine was 1:1.5, the temperature was 150° C., the pressure was 0.5 MPa, 202 g of bis(trifluoromethyl) disulfide and 106.5 g of chlorine were fed into the reaction, and 270.98 g of the product was obtained, with a content of 99.00% and a yield of 98.27%.

[0042] Example 9

[0043] The other conditions were the same as those in Example 1, except that the molar ratio of bis(trifluoromethyl) disulfide and chlorine was 1:1, the temperature was 60° C., the pressure was normal pressure, 202 g of bis(trifluoromethyl) disulfide and 71 g of chlorine were fed into the reaction, and 256.65 g of the product was obtained, with a content of 98.54% and a yield of 92.64%.

[0044] Example 10

[0045] The other conditions were the same as those in Example 1, except that the molar ratio of bis(trifluoromethyl) disulfide and chlorine was 1:5, the temperature was 60° C., the pressure was normal pressure, 202 g of bis(trifluoromethyl) disulfide and 355 g of chlorine were fed into the reaction, and 272.12 g of the product was obtained, with a content of 99.11% and a yield of 98.79%.

[0046] Embodiment 11

[0047] In a fixed bed reactor equipped with molecular sieves, bis(trifluoromethyl) disulfide and chlorine (molar ratio of 1:1.5) are introduced from the bottom of the fixed bed, the tower bottom and the fixed bed are heated, the temperature is set to 60°C, the pressure is normal pressure, and the materials enter the bed in gaseous form for reaction. The reaction product passes through the bed, and the product enters two-stage condensation and liquefaction to obtain the product. Excess chlorine enters the liquid alkali for absorption. The reaction is fed with 202g of bis(trifluoromethyl) disulfide and 106.5g of chlorine, and 271.3g of product is obtained, with a content of 98.82% and a yield of 98.20%.

[0048] Example 12

[0049] In a fixed bed reactor filled with resin, bis(trifluoromethyl) disulfide and chlorine (molar ratio of 1:1.5) are introduced from the bottom of the fixed bed, the tower bottom and the fixed bed are heated, the temperature is set to 60°C, the pressure is normal pressure, and the materials enter the bed in gaseous form for reaction. The reaction product passes through the bed, and the product enters two-stage condensation and liquefaction to obtain the product. Excess chlorine enters the liquid alkali for absorption. The reaction is fed with 202g of bis(trifluoromethyl) disulfide and 142g of chlorine, and 270.68g of product is obtained, with a content of 98.76% and a yield of 97.92%.

Claims

1. A method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination, characterized in that: Bis(trifluoromethyl) disulfide and chlorine react continuously in a fixed bed reactor equipped with a catalyst to generate trifluoromethyl chlorosulfide. The material enters the fixed bed reactor in the form of gas. The reaction temperature is 20~150℃, and the catalyst is activated carbon, resin or molecular sieve.

2. The method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination according to claim 1, characterized in that: The fixed bed reactor adopts the commonly used axial, radial or shell-and-tube reactor.

3. The method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination according to claim 1, characterized in that: The molar ratio of bis(trifluoromethyl) disulfide to chlorine is 1:1~5.

4. The method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination according to claim 3, characterized in that: The molar ratio of bis(trifluoromethyl) disulfide to chlorine is 1:1~3.

5. The method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination according to claim 1, characterized in that: The reaction pressure is 0~0.5MPa.

6. The method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination according to claim 5, characterized in that: The reaction temperature is 20~100℃.

7. The method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination according to claim 6, characterized in that: The reaction temperature is 50~80℃.

8. The method for synthesizing trifluoromethyl sulfonyl chloride by continuous chlorination according to claim 1, characterized in that: The reaction is post-treated, and the specific operation of the post-treatment is as follows: the excess chlorine gas enters the liquid alkali for absorption, and the product trifluoromethyl sulfhydryl chloride is condensed and liquefied at -15°C and collected.

Images