Novel preparation method of bis (trifluoromethyl) sulfide

Abstract

The invention discloses a novel preparation method of bis (trifluoromethyl) sulfide. According to the scheme disclosed by the invention, dimethyl sulfide, chlorine and fluoride are taken as raw materials, the bis (trifluoromethyl) sulfide is synthesized through two-step reaction of photochlorination and fluorination, the two-step reaction temperature is both carried out within 80 DEG C, and the reaction conditions are mild.

Description

Technical Field

[0001] The invention relates to a method for synthesizing a novel insulating gas, and in particular to a method for preparing bistrifluoromethyl sulfide. Background Art

[0002] Bis(trifluoromethyl)sulfide(CF 3 SCF 3 ) as a new type of insulating gas, its dielectric strength is SF 6 1.5 times of the original, liquefaction temperature is -22℃, low toxicity (LC 50 >20000ppm), GWP is 3, and thermal stability is good. It is a new type of insulating gas whose comprehensive performance meets the requirements of power grid use. 3 SCF 3 However, the raw materials CF used in the above two methods are 3 SSCF 3 Highly toxic low-boiling substances that are not easily available. Summary of the invention

[0003] In view of the shortcomings and defects of the prior art, the present invention provides a method for synthesizing bistrifluoromethyl sulfide with low toxicity.

[0004] To this end, the present invention provides a novel method for preparing bis(trifluoromethyl) sulfide, comprising the following steps:

[0005] S1, dimethyl sulfide and chlorine react at 50-80°C under light and Lewis acid catalyst to prepare perchloromethyl sulfide;

[0006] S2, at 60-80° C. and in the presence of a liquid phase fluorination catalyst, the perchloromethyl sulfide prepared in step S1 is subjected to a fluorination reaction with a fluoride in an organic solvent to prepare bistrifluoromethyl sulfide.

[0007] Alternatively, the reaction of dimethyl sulfide and chlorine is carried out in a gas phase tubular reactor.

[0008] Alternatively, the Lewis acid catalyst is iron pentacarbonyl, aluminum oxide fluoride or ruthenium hexacarbonyl chloride.

[0009] An optional solution is that the wavelength of light is 280 to 400 nm.

[0010] Alternatively, the fluorination reaction of perchloromethyl sulfide with a fluoride is carried out in a tank reactor.

[0011] Optionally, the fluoride is hydrogen fluoride, sodium fluoride or silver fluoride.

[0012] Optionally, the liquid phase fluorination catalyst is titanium tetrafluoride, niobium pentafluoride or antimony pentafluoride.

[0013] An optional solution is that the organic solvent is selected from one or a mixture of two or more of tetrahydrofuran, dimethylformamide, acetonitrile and ethylene glycol dimethyl ether.

[0014] The invention uses dimethyl sulfide, chlorine and fluoride as raw materials, and prepares bistrifluoromethyl sulfide through two-step reactions of photochlorination and fluorination. The reaction temperatures of the two steps of the invention are both within 80° C., and the reaction conditions are mild.

[0015] The catalyst is used in both steps of the reaction to significantly improve the yield of bis(trifluoromethyl)sulfide, wherein the yield of bis(trifluoromethyl)sulfide is above 80% and can be as high as 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The chromatographic detection result of Example 1 is shown. DETAILED DESCRIPTION

[0017] Unless otherwise specified, the scientific and technical terms in the present invention are understood according to the knowledge of ordinary technicians in the relevant field. It should also be understood that the temperatures and concentrations involved in this article are approximate values ​​for illustrative purposes. Although methods and materials similar or equivalent to the methods and materials described herein can be used for the implementation of the present disclosure, some suitable methods and materials are described below. The publications, patent applications, patents and other references mentioned herein are partially incorporated herein by reference. In the event of a conflict, this article shall prevail.

[0018] The present invention uses dimethyl sulfide, chlorine and fluoride as raw materials, and synthesizes bistrifluoromethyl sulfide through two steps of photochlorination and fluorination. The reaction route is as follows:

[0019]

[0020] The catalyst used in the present invention can be a corresponding commercial product, or can be prepared by a synthesis method including but not limited to those known to those skilled in the art.

[0021] The present invention is further described in detail below in conjunction with the examples, but the scope of the present invention is not limited. The materials, methods, solution concentrations and embodiments described in the following examples are exemplary only and are not intended to be limiting. In the specific scheme, those skilled in the art can optimize the values ​​of the operating parameters such as the material ratio, concentration, temperature, reaction time, etc. involved in the method according to the disclosure of the present invention using conventional experimental time periods to achieve the purpose of the present invention.

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

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

[0024] Embodiment 1:

[0025] Preparation of perchloromethyl sulfide:

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

[0027] Preparation of bis(trifluoromethyl)sulfide:

[0028] In a tank reactor, perchloromethyl sulfide (500 g), SbF 5 (20g) and an appropriate amount of acetonitrile (soluble reactants), slowly introduce HF (200g), control the top pressure at 0.1MPa, the reaction temperature at 60°C, react for 2h, absorb the tail gas with water, and collect 305g of the product in a -40°C cold trap, with a yield of 97%.

[0029] The results of chromatographic testing were as follows Figure 1 shown.

[0030] Embodiment 2:

[0031] Preparation of perchloromethyl sulfide:

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

[0033] Preparation of bis(trifluoromethyl)sulfide:

[0034] In a tank reactor, perchloromethyl sulfide (500 g), TiF 4(15g) and appropriate amount of DMF, slowly add KF (200g), control the top pressure of the tower to 0.1MPa, the reaction temperature to 70℃, react for 3h, pass water into the tail gas for absorption, and collect 295g of the product in a -40℃ cold trap, with a yield of 95%.

[0035] Embodiment 3:

[0036] Preparation of perchloromethyl sulfide:

[0037] The temperature in the tubular reactor was gradually raised to 80°C at a heating rate of 5°C / min, a mixture of dimethyl sulfide (300 g) and hexacarbonyl ruthenium chloride (1.0 g) was introduced, a light source (wavelength 280-400 nm) was turned on, chlorine gas (360 g) was introduced, and the reaction was carried out for 40 hours. 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 tank reactor, perchloromethyl sulfide (500 g), NbF 5 (15g) and an appropriate amount of THF, slowly add NaF (200g), control the top pressure of the tower to 0.1MPa, the reaction temperature to 80°C, react for 2h, pass water into the tail gas for absorption, and collect 300g of the product in a -40°C cold trap, with a yield of 96%.

[0040] Embodiment 4~8:

[0041] Example 4-: The difference from Example 1 is that the type of catalyst is changed, and the reaction temperature of the bistrifluoromethyl sulfide preparation step and the mass ratio of the catalyst to the mass of perchloromethyl sulfide are adjusted. The reaction conditions and results are shown in Table 1.

[0042] Comparative Example 1-2:

[0043] The difference between Comparative Example 1 and Example 1 is that no catalyst is used in the preparation process of bistrifluoromethyl sulfide. The difference between Comparative Example 2 and Example 1 is that the catalyst used in the preparation process of bistrifluoromethyl sulfide is KF.

[0044] Table 1

[0045]

[0046] The above descriptions are only some embodiments of the present invention and do not limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A novel method for preparing bis(trifluoromethyl) sulfide, characterized in that: The steps include: S1, dimethyl sulfide and chlorine react at 50-80°C under light and Lewis acid catalyst to prepare perchloromethyl sulfide; S2, at 60-80° C. and in the presence of a liquid phase fluorination catalyst, the perchloromethyl sulfide prepared in step S1 is subjected to a fluorination reaction with a fluoride in an organic solvent to prepare bistrifluoromethyl sulfide.

2. The novel preparation method of 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 novel preparation method of bis(trifluoromethyl) sulfide according to claim 1, characterized in that: The Lewis acid catalyst is iron pentacarbonyl, aluminum oxide fluoride or ruthenium hexacarbonyl chloride.

4. The method for preparing bis(trifluoromethyl) sulfide according to claim 1, characterized in that: The wavelength of light is 280-400nm.

5. The novel preparation method of bis(trifluoromethyl) sulfide according to claim 1, characterized in that: The fluorination reaction of perchloromethyl sulfide with fluoride is carried out in a tank reactor.

6. The novel preparation method of bis(trifluoromethyl) sulfide according to claim 1, characterized in that: The fluoride is hydrogen fluoride, sodium fluoride or silver fluoride.

7. The novel preparation method of bis(trifluoromethyl) sulfide according to claim 1, characterized in that: The liquid phase fluorination catalyst is titanium tetrafluoride, niobium pentafluoride or antimony pentafluoride.

8. The novel preparation method of bis(trifluoromethyl)sulfide according to claim 1, characterized in that: The organic solvent is selected from one or a mixture of two or more of tetrahydrofuran, dimethylformamide, acetonitrile and ethylene glycol dimethyl ether.

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