Synthetic method of trifluoromethyl sulfide

Abstract

The invention discloses a synthesis method of trifluoromethyl sulfide, which comprises the following steps: in the presence of a catalyst, reacting trifluoroiodomethane with trifluoromethyl persulfane, and synthesizing to obtain the trifluoromethyl sulfide. The trifluoromethyl sulfide synthesis method provided by the invention has the advantages of few by-products and high reaction efficiency.

Description

TECHNICAL FIELD

[0001] The application discloses a synthesis method of trifluoromethyl sulfide, and particularly relates to a method for synthesizing trifluoromethyl sulfide by reacting trifluoromethyl perthioalkane with trifluoroiodomethane in the presence of a fluoride catalyst in a tubular reactor. BACKGROUND

[0002] Ditrifluoromethyl sulfide (CF3SCF3) has the application potential of replacing SF6. There are multiple routes for preparing CF3SCF3 reported in the existing documents: Brandt reported a method for preparing a trifluoromethyl sulfide, raw material ditrifluoromethyl perthioalkane was reacted at room temperature for 13 days under ultraviolet irradiation to obtain the trifluoromethyl sulfide; CN202410537083.1 reported a method for preparing trifluoromethyl sulfide by catalytic thermal desulfurization from ditrifluoromethyl perthioalkane, but the reaction temperature of the method is 200~500 o C, the generated sulfur will cause pipeline blockage, and the byproduct polysulfide has high boiling point and great toxicity. SUMMARY

[0003] In view of the defects and shortcomings of the prior art, the application provides a synthesis method of trifluoromethyl sulfide.

[0004] Therefore, the synthesis method of trifluoromethyl sulfide provided by the application comprises the following steps: under the condition that a catalyst exists and the temperature is 150 o C~200 o C, trifluoroiodomethane is reacted with trifluoromethyl perthioalkane to synthesize trifluoromethyl sulfide; the catalyst comprises a carrier and an active component loaded on the carrier, the carrier is magnesium fluoride, and the active component is copper or silver.

[0005] Optionally, the reaction is carried out in a gas-phase tubular reactor.

[0006] Optionally, the molar ratio of the trifluoroiodomethane to the trifluoromethyl perthioalkane is 1: (1~1.5).

[0007] Optionally, the reaction contact time is 3~10s.

[0008] Optionally, the mass of the active component in the catalyst is 5%~10% of the mass of the carrier.

[0009] Compared with the prior art, the application reduces the initiation temperature of trifluoromethylthio radical by introducing trifluoroiodomethane, and improves the problems of sulfur blocking the pipeline and the high toxicity of the byproduct polysulfane. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1The gas chromatogram of the crude product of trifluoromethyl sulfide of the present application (the peaks from left to right in the figure are 1#-12#).

[0011] Figure 2 The gas chromatogram of the pure product of trifluoromethyl sulfide of the present application. DETAILED DESCRIPTION

[0012] Unless otherwise defined, scientific and technical terms used in this application have the meanings commonly understood by one of ordinary skill in the art. It is also to be understood that the mention of a temperature, concentration, and the like, is meant to refer to approximate values, and are intended to be used for descriptive purposes, unless otherwise indicated. Although methods and materials similar or equivalent to those described herein can be used in the practice of the present disclosure, certain suitable methods and materials are described below. The publications, patent applications, patents, and other references noted herein are incorporated by reference in their entirety, as are other referenced technical publications, which describe methods and materials which can be used in connection with the methods described in the present disclosure. Unless otherwise indicated, the materials, methods, solution concentrations, and examples described herein are illustrative only and are not intended to be limiting. In particular, one of ordinary skill in the art will appreciate that the methods of the present disclosure can be practiced by one of ordinary skill in the art with modifications to the methods and materials described in the present disclosure, using no more than routine experimentation based on the present disclosure.

[0013] The method for preparing trifluoromethyl sulfide of the present application, at 150 o C o C, the trifluoromethyl sulfide is prepared by one-step reaction. The specific reaction equation is as follows:

[0014] Since the stability of bis-trifluoromethyl per sulfane is high, the cracking temperature is often high, and the generated sulfur will sublimate at the dead angle or pipe orifice of the pipeline at a lower temperature, causing pipeline blockage, so that the reaction cannot continue. At the same time, the generated polysulfur material is highly toxic and has a high boiling point, which also brings health and safety hazards to the workers. The thermal cracking mechanism of bis-trifluoromethyl per sulfane is as follows:

[0015] The present application considers that the C-I bond energy in trifluoroiodomethane is lower (53.3 kcal / mol) than 200 o C, and free radicals can be generated by cracking, and designs to introduce trifluoroiodomethane into the trifluoromethyl per sulfane system. The trifluoromethyl radical generated after the cracking of trifluoroiodomethane promotes the homolysis of trifluoromethyl per sulfane through a chain reaction, generates a trifluoromethylthio radical, improves the free radical initiation efficiency, and the byproduct trifluoromethylthio iodine has good thermal stability and is not easy to cause pipeline blockage, which can improve the defects of the prior art. The cracking mechanism of trifluoroiodomethane is as follows:

[0016] The product in the present application is detected by gas chromatography. The chromatographic conditions are as follows: vaporizing chamber 200℃, detector 200℃, chromatographic column gaspro column, specification 30m x 0.25mm, column temperature initial 50℃, constant temperature for 5 minutes, programmed temperature rising to 200℃ at 15℃ / min, constant temperature for 10 minutes.

[0017] The following combined examples further illustrate the present application in detail, but do not limit the scope of the present application.

[0018] The catalyst used in the following examples is prepared as follows (taking silver as an example of active component): 5g of silver carbonate is dissolved, then 100g of prepared magnesium fluoride carrier is added, and the solution is immersed for 48 hours, then the solution is dried, and the catalyst is obtained by calcining in a muffle furnace at 800 o C for 24 hours (active component Ag proportion 5%).

[0019] Example 1: 50 mL of catalyst Ag / MgF2 is weighed into a tubular reactor, heated to 170℃±2, and a flow pump is used to control the input of trifluoromethylsulfane, a gas flow meter is used to control the residence time of trifluoroiodomethane of 5s, the molar ratio of trifluoroiodomethane to trifluoromethylsulfane is 1:1.3, the product is cooled by a buffer tank, and gas phase is collected by a cold trap, and gas chromatography analysis is performed.

[0020] The gas chromatography detection results are shown in Figure 1 , Table 1 and Figure 2 and Table 2.

[0021] Table 1 Figure 1 The spectrum information is shown in

[0022] Figure 1 The results of Table 1 show that at the outlet of the reaction tube, after removing the raw material CF3SSCF3 (which can be recycled), the purity of the crude product CF3SCF3 is 95%, indicating that the by-products of the process are few.

[0023] Table 2 Figure 2 The spectrum information is shown in

[0024] Figure 2 The results show that after pressurized rectification of the crude product CF3SCF3, the purity of the pure product CF3SCF3 is as high as 100%, indicating that the purification process of the present application is simple.

[0025] Examples 2-6: The operation process of examples 2-6 is similar to example 1, except that the catalyst is changed, and the proportion of active components is adjusted, and the reaction temperature and residence time are adjusted. The reaction results are shown in Table 3.

[0026] Table 3

[0027] Examples 7-9: The operation process of examples 7-9 is similar to example 1, except that the molar ratio of trifluoroiodomethane to trifluoromethylpersulfane is changed, and the reaction temperature and residence time are adjusted. The reaction results are shown in Table 4.

[0028] Table 4

[0029] Comparative examples 1-2: Comparative example 1 is different from example 1 in that no catalyst is used in the preparation of trifluoromethyl sulfide. Comparative examples 2 and 3 are different from example 1 in that Fe and Ru are used as active components in the preparation of trifluoromethyl sulfide. The results are shown in Table 5.

[0030] Table 5

[0031] The above is only part of the embodiments of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification made according to the technical essence of the present application to the above embodiments are within the scope of the technical solutions of the present application.

Claims

1. A method for the synthesis of trifluoromethyl sulfides, characterized in that, in the presence of a catalyst and at a temperature of 150 o C o C under the conditions of trifluoroiodomethane and trifluoromethylsulfoxide to synthesize trifluoromethyl sulfide; the catalyst comprises a carrier and an active component supported on the carrier, the carrier is magnesium fluoride, and the active component is copper or silver.

2. The method for synthesizing trifluoromethyl sulfide according to claim 1, characterized in that, The reaction is carried out in a gas phase tubular reactor.

3. The method of claim 1, wherein the compound is ###0002### 2 3 The molar ratio of trifluoroiodomethane to trifluoromethylsulfonium peroxide is 1: (1-1.5).

4. The method of claim 1, wherein the compound is ###0002### 2 The reaction contact time is 3-10 s.

5. The method for synthesizing trifluoromethyl sulfide according to claim 5, characterized in that, The mass of the active component in the catalyst is 5%-10% of the mass of the carrier.

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