A process for the preparation of a bis-trifluoromethyl sulfide

Abstract

The application discloses a novel preparation method of a bistrifluoromethyl sulfide. The disclosed scheme uses dimethyl sulfide, chlorine and fluoride as raw materials, and obtains the bistrifluoromethyl sulfide through a photochlorination and fluorination two-step reaction. The two-step reaction temperature of the application is within 80 DEG C, and the reaction condition is mild.

Description

Technical Field

[0001] This invention relates to a method for synthesizing a novel insulating gas, specifically a method for preparing bis(trifluoromethyl)sulfide. Background Technology

[0002] Bis(trifluoromethyl) sulfide (CF3SCF3), as a novel insulating gas, has an insulating strength 1.5 times that of SF6 and a liquefaction temperature of -22°C. o C, Low toxicity (LC) 50 With a concentration of >20000ppm, a GWP of 3, and good thermal stability, it is a new type of insulating gas whose comprehensive performance meets the requirements of power grid use. Existing technologies CN202410537079.5 and CN20241537083.1 disclose methods for preparing CF3SCF3; however, the raw materials used in these two methods, CF3SSCF3, are highly toxic, low-boiling compounds that are difficult to obtain. Summary of the Invention

[0003] In view of the shortcomings and defects of the existing technology, the present invention provides a method for synthesizing bis(trifluoromethyl) sulfide with low toxicity.

[0004] Therefore, the present invention provides a novel preparation method for a bis(trifluoromethyl) sulfide comprising the following steps:

[0005] S1, dimethyl sulfide and chlorine are reacted to prepare perchloromethyl sulfide under the action of light and Lewis acid catalyst at 50-80℃;

[0006] S2, at 60~80 o Under C conditions and with the action of a liquid-phase fluorination catalyst, the perchloromethyl sulfide obtained in step S1 is reacted with fluorides in an organic solvent to prepare bis(trifluoromethyl) sulfide.

[0007] An alternative is to carry out the reaction of dimethyl sulfide and chlorine in a gas-phase tubular reactor.

[0008] Alternatively, the Lewis acid catalyst may be pentacarbonyl iron, alumina fluoride, or ruthenium hexacarbonyl chloride.

[0009] An alternative is to use a light wavelength of 280 ~ 400nm.

[0010] An alternative is to carry out the fluorination reaction of perchloromethyl sulfide with fluoride in a batch reactor.

[0011] Alternatively, the fluoride may be hydrogen fluoride, sodium fluoride, or silver fluoride.

[0012] Alternatively, the liquid-phase fluorination catalyst may be titanium tetrafluoride, niobium pentafluoride, or antimony pentafluoride.

[0013] Alternatively, the organic solvent may be selected from one or a mixture of two or more of tetrahydrofuran, dimethylformamide, acetonitrile, and ethylene glycol dimethyl ether.

[0014] This invention uses dimethyl sulfide, chlorine, and fluorides as raw materials to prepare bis(trifluoromethyl) sulfide through a two-step reaction of photochlorination and fluorination. The reaction temperature of both steps is below 80°C, and the reaction conditions are mild.

[0015] The present invention utilizes a catalyst in both reaction steps, significantly improving the yield of bis(trifluoromethyl) sulfide. The yield of bis(trifluoromethyl) sulfide is above 80%, and can reach as high as 95%. Attached Figure Description

[0016] Figure 1 The results are chromatographic detection results for Example 1. Detailed Implementation

[0017] Unless otherwise specified, the scientific and technical terms used in this invention are for the understanding of one of ordinary skill in the art. It should also be understood that temperatures and concentrations used herein are approximate and for illustrative purposes. While similar or equivalent methods and materials may be used in the implementation of this disclosure, some suitable methods and materials are described below. Publications, patent applications, patents, and other references mentioned herein are incorporated herein by reference in part, and in the event of any conflict, this document shall prevail.

[0018] This invention uses dimethyl sulfide, chlorine, and fluorides as raw materials to synthesize bis(trifluoromethyl) sulfide through a two-step reaction of photochlorination and fluorination. The reaction route is as follows:

[0019]

[0020] The catalyst used in this invention can be a commercially available product or can be prepared using synthetic methods known to those skilled in the art, including but not limited to those known to those skilled in the art.

[0021] The present invention will be further described in detail below with reference to embodiments, but this does not limit the scope of the invention. The materials, methods, solution concentrations, and embodiments described in the following embodiments are merely exemplary and are not intended to be limiting. In specific solutions, those skilled in the art can optimize the values ​​of operating parameters such as the ratio of substances, concentration, temperature, and reaction time involved in the method using conventional experimental periods based on the content disclosed in the present invention to achieve the purpose of the present invention.

[0022] In the following examples, the final product was detected by gas chromatography. The chromatographic conditions were as follows: vaporization chamber 200°C, detector 200°C, gaspro column with a specification of 30m × 0.25mm, initial column temperature of 50°C, constant temperature for 5 minutes, temperature increased to 200°C at a program of 15°C / min, and constant temperature for 10 minutes.

[0023] All raw materials used in the following examples are commercially available products.

[0024] Example 1:

[0025] Preparation of perchloromethyl sulfide:

[0026] The temperature was gradually increased to 50°C in a tubular reactor at a heating rate of 5°C / min. A mixture of dimethyl sulfide (300 g) and ferric pentacarbonyl (0.8 g) was introduced. The light source (wavelength 280 ~ 400 nm) was turned on, and chlorine gas (360 g) was introduced. The reaction was carried out for 48 h. After the reaction tail gas was separated by distillation in a gas-liquid separator, 610 g of organic perchloromethyl sulfide was collected, with a yield of 90%.

[0027] Preparation of bis(trifluoromethyl) sulfide:

[0028] In a batch reactor, 500 g of perchloromethyl sulfide, 20 g of SbF5, and an appropriate amount of acetonitrile (to dissolve the reactants) were added sequentially. 200 g of HF was slowly introduced, and the pressure at the top of the reactor was controlled at 0.1 MPa. The reaction temperature was 60°C, and the reaction was carried out for 2 hours. The tail gas was absorbed by water and then discharged at -40°C. o 305g of product was collected in the C cold trap, with a yield of 97%.

[0029] Chromatographic analysis showed the following results: Figure 1 As shown.

[0030] Example 2:

[0031] Preparation of perchloromethyl sulfide:

[0032] The temperature was gradually increased to 60°C in a tubular reactor at a heating rate of 5°C / min. A mixture of dimethyl sulfide (300 g) and ruthenium hexacarbonyl chloride (0.5 g) was introduced, the light source (wavelength 280 ~ 400 nm) was turned on, and chlorine gas (360 g) was introduced. The reaction was carried out for 36 h. After the reaction tail gas was separated by gas-liquid separator by distillation, 630 g of organic perchloromethyl sulfide was collected, with a yield of 95%.

[0033] Preparation of bis(trifluoromethyl) sulfide:

[0034] In a batch reactor, 500g of perchloromethyl sulfide, 15g of TiF4, and an appropriate amount of DMF were added sequentially, followed by the slow addition of KF (200g). The pressure at the top of the reactor was controlled at 0.1MPa, the reaction temperature was 70℃, and the reaction was carried out for 3 hours. The tail gas was then absorbed by water and discharged at -40℃. o 295 grams of product were collected in the C cold trap, with a yield of 95%.

[0035] Example 3:

[0036] Preparation of perchloromethyl sulfide:

[0037] The temperature was gradually increased to 80°C in a tubular reactor at a heating rate of 5°C / min. A mixture of dimethyl sulfide (300 g) and ruthenium hexacarbonyl chloride (1.0 g) was introduced, the light source (wavelength 280 ~ 400 nm) was turned on, and chlorine gas (360 g) was introduced. The reaction was carried out for 40 h. After the reaction tail gas was separated by a gas-liquid separator, 640 g of organic perchloromethyl sulfide was collected, with a yield of 97%.

[0038] Preparation of bis(trifluoromethyl) sulfide:

[0039] In a batch reactor, 500 g of perchloromethyl sulfide, 15 g of NbF5, and an appropriate amount of THF were added sequentially, followed by the slow addition of NaF (200 g). The pressure at the top of the reactor was controlled at 0.1 MPa, the reaction temperature was 80 °C, and the reaction was carried out for 2 hours. The tail gas was absorbed by water and then discharged at -40 °C. o 300g of product was collected in the C cold trap, yielding 96%.

[0040] Examples 4-8:

[0041] Example 4~: Unlike Example 1, the type of catalyst was changed, and the reaction temperature and the mass ratio of the catalyst to the total chloromethyl sulfide in the preparation step were adjusted. The reaction conditions and results are shown in Table 1.

[0042] Comparative Examples 1-2:

[0043] The difference between Comparative Example 1 and Example 1 is that no catalyst was used in the preparation of bis(trifluoromethyl) sulfide. The difference between Comparative Example 2 and Example 1 is that KF was used as the catalyst in the preparation of bis(trifluoromethyl) sulfide.

[0044] Table 1

[0045]

[0046] The above description is only a partial embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a bis(trifluoromethyl)sulfide, characterized in that, Includes the following steps: S1, dimethyl sulfide and chlorine react to prepare perchloromethyl sulfide under conditions of 50–80°C, light irradiation, and Lewis acid catalyst; the light irradiation wavelength is 280–400 nm; the Lewis acid catalyst is pentacarbonylferric chloride or hexacarbonylruthenium chloride. S2, under conditions of 60-80℃ and the action of a liquid-phase fluorination catalyst, the perchloromethyl sulfide obtained in step S1 is reacted with a fluoride in an organic solvent to prepare bis(trifluoromethyl) sulfide; the liquid-phase fluorination catalyst is titanium tetrafluoride, niobium pentafluoride, or antimony pentafluoride; the organic solvent is selected from one or a mixture of two or more of tetrahydrofuran, dimethylformamide, acetonitrile, and ethylene glycol dimethyl ether; the fluoride is hydrogen fluoride, sodium fluoride, or potassium fluoride.

2. The method for preparing bis(trifluoromethyl)sulfide according to claim 1, characterized in that, The reaction of dimethyl sulfide and chlorine is carried out in a gas-phase tubular reactor.

3. The method for preparing bis(trifluoromethyl)sulfide according to claim 1, characterized in that, The fluorination reaction of perchloromethyl sulfide with fluorides is carried out in a batch reactor.

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