A process for the preparation of a bistrifluoromethyl sulfide
By reacting pyrolysis gas with trifluoromethylthio salt in an organic solvent in the presence of a composite catalyst and a protic acid, bis(trifluoromethyl)sulfide was prepared, solving the biohazard problem caused by the use of highly toxic intermediates in existing technologies and realizing an efficient and safe preparation method.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAN MODERN CHEM RES INST
- Filing Date
- 2024-12-02
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies use highly toxic intermediates in the preparation of bis(trifluoromethyl) sulfide, posing significant biological hazards and making it difficult to achieve safe and efficient preparation.
In the presence of a composite catalyst and a protic acid, the product is recovered by reacting the cracked gas with the trifluoromethylthio salt in an organic solvent at 0–50 °C and using a condenser. A mixture of crown ether and alkali metal bromide is used as the composite catalyst. The reaction temperature is controlled at -30–10 °C and the product is recovered by cooling in a dry ice bath.
A high yield (over 90%) of bis(trifluoromethyl) sulfide was achieved, and the reaction was safe and efficient, avoiding the use of highly toxic intermediates.
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Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing a novel insulating gas, specifically a method for preparing a 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, a liquefaction temperature of -22℃, and 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 for power grid use. Existing technologies CN202410537079.5 and CN20241537083.1 disclose methods for preparing CF3SCF3; however, both of these methods use the highly toxic intermediate CF3SSCF3, which poses a significant biohazard. Summary of the Invention
[0003] In view of the shortcomings and defects of the existing technology, the present invention provides a method for preparing bis(trifluoromethyl) sulfide.
[0004] Therefore, the preparation method of bis(trifluoromethyl) sulfide provided by the present invention includes the following steps:
[0005] Under conditions of 0–50°C and in the presence of a composite catalyst and a protic acid, the cracked gas reacts with trifluoromethylthio-based salt in an organic solvent. The reaction gas generated during the reaction is cooled and the product is recovered after passing through a condenser. The temperature of the condenser is -30 to 10°C, and the cooling temperature is lower than the temperature of the condenser.
[0006] The cracked gas is the gas produced by the cracking reaction of tetrafluoroethylene and sulfur at a reaction temperature of 400-600°C.
[0007] The composite catalyst is a mixture of crown ether and alkali metal bromide.
[0008] Alternatively, the cooling recovery can be carried out in a dry ice bath.
[0009] Alternatively, the crown ether may be an 18-crown-6 ether, a 15-crown-5 ether, a benzo-18-crown-6 ether, or a dibenzo-18-crown-6 ether; and the alkali metal bromide may be KBr, NaBr, KBr, or KBr.
[0010] Alternatively, the composite catalyst may be a mixture of 18-crown 6-ether and KBr, a mixture of 15-crown 5-ether and NaBr, a mixture of benzo-18-crown 6-ether and KBr, or a mixture of dibenzo-18-crown 6-ether and KBr.
[0011] Alternatively, the protic acid may be tetrafluoroboric acid, hexafluorophosphate, trifluoroacetic acid, or pentafluoroantimonic acid.
[0012] Alternatively, the trifluoromethylthio salt may be trifluoromethylthiotetramethylammonium, trifluoromethylthio(2,2'-bipyridine)copper, or trifluoromethylthiosilver.
[0013] Alternatively, the organic solvent may be tetrahydrofuran, ethylene glycol dimethyl ether, dimethylformamide, dimethylacetamide, or dimethylthioformamide.
[0014] An alternative approach is that the method for preparing the pyrolysis gas includes: heating sulfur to 400-600°C in a fixed-bed reactor, and then introducing tetrafluoroethylene gas to react and generate pyrolysis gas.
[0015] An alternative approach is to react the cracked gas with the trifluoromethylthiocyanate for 1 to 5 hours.
[0016] Alternatively, the mass ratio of the composite catalyst to trifluoromethyl sulfide is 0.1 to 0.8:1.
[0017] The synthesis method of the present invention is safe, efficient and highly selective, and the yield of bis(trifluoromethyl)sulfide can reach more than 90% under optimal conditions. Attached Figure Description
[0018] Figure 1 The results are obtained from the gas chromatography analysis of the product prepared in Example 1. Detailed Implementation
[0019] Unless otherwise specified, the scientific and technical terms used in this invention are intended for understanding by one of ordinary skill in the art.
[0020] It should also be understood that the temperatures and concentrations mentioned herein are approximate values used 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.
[0021] This invention provides an in-situ preparation of difluorocarbon sulfide via the reaction of tetrafluoroethylene with sulfur, followed by a reaction with trifluoromethylthiosulfate to prepare bis(trifluoromethyl)sulfide. The specific reaction equation is as follows:
[0022]
[0023] The present invention will be further described in detail below with reference to the embodiments, but this does not limit the scope of the invention. The materials, methods, solution concentrations, and embodiments described in the following examples are merely exemplary and are not intended to be limiting. In specific solutions, those skilled in the art can use conventional experimental methods based on the disclosure of the present invention to optimize the values of specific substances, substance ratios, concentrations, temperatures, reaction times, and other operating parameters involved in the method to achieve the objectives of the present invention.
[0024] The catalyst used in this invention can be a commercially available product or can be prepared using synthesis methods known to those skilled in the art, including but not limited to those known to those skilled in the art.
[0025] In the following examples, the products were 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.
[0026] Example 1:
[0027] Preparation of the pyrolysis gas used in this embodiment:
[0028] Sulfur (300g) was gradually heated to 450℃ in a fixed-bed reactor at a heating rate of 10℃ / min, and tetrafluoroethylene (1000g) gas was introduced. The cracked gas produced by the reaction was reserved.
[0029] Preparation of bis(trifluoromethyl) sulfide:
[0030] In a batch reactor, trifluoromethylthiotetramethylammonium (175g), potassium bromide (120g), dibenzo-18-crown-6 ether (10g), hexafluorophosphate (5g), and dimethylformamide (200mL) were added sequentially. Mechanical stirring was started at 800 rpm, and the reaction temperature was maintained at 25°C. After 10 minutes, the prepared pyrolysis gas was introduced. The condenser was cooled to -5°C, and the gas from the top of the condenser was collected in a dry ice bath. After 3 hours of reaction, a sample was taken and analyzed by gas chromatography (results are shown in the figure). Figure 1 As shown), bis(trifluoromethyl) sulfide (258 g) was received, with a yield of 93%.
[0031] Example 2:
[0032] Preparation of the pyrolysis gas used in this embodiment:
[0033] Sulfur (25g) was gradually heated to 500℃ in a fixed-bed reactor at a heating rate of 8℃ / min, and tetrafluoroethylene (100g) gas was introduced to react and prepare cracked gas for later use.
[0034] Preparation of bis(trifluoromethyl) sulfide:
[0035] In a batch reactor, copper trifluoromethylthio(2,2'-bipyridine) (10 g), sodium bromide (3.2 g), 15-crown-5 ether (0.5 g), tetrafluoroboric acid (0.1 g), and anhydrous tetrahydrofuran (50 mL) were added sequentially. Mechanical stirring was started at 800 r / min, and the reaction temperature was maintained at 40 °C. After 10 minutes, the prepared pyrolysis gas was introduced, and the condenser was cooled to 5 °C. The gas at the top of the condenser was collected in a dry ice bath. After reacting for 2 hours, the mixture was cooled, and a sample was taken. Gas chromatography analysis revealed that bis(trifluoromethyl) sulfide (5 g) was obtained, with a yield of 91%.
[0036] Example 3:
[0037] Preparation of the pyrolysis gas used in this embodiment:
[0038] Sulfur (20g) was gradually heated to 550℃ in a fixed-bed reactor at a heating rate of 8℃ / min, and tetrafluoroethylene (60g) gas was introduced to prepare pyrolysis gas for later use.
[0039] Preparation of bis(trifluoromethyl) sulfide:
[0040] In a batch reactor, trifluoromethyl thiosilver (2.1 g), potassium bromide (1.5 g), benzo
[18] 18 crown 6 ether (0.01 g), pentafluoroantimonic acid (0.001 g), and dimethyl thioformamide (5 mL) were added sequentially. Mechanical stirring was started at 800 r / min, and the reaction temperature was maintained at 30 °C. After 10 minutes, the prepared pyrolysis gas was introduced, and the condenser was cooled to 5 °C. The gas at the top of the condenser was collected in a dry ice bath. After reacting for 2 hours, the mixture was cooled, and a sample was taken. Gas chromatography analysis revealed that bis(trifluoromethyl) sulfide (1.6 g) was obtained, with a yield of 94%.
[0041] Examples 4-8:
[0042] Examples 4-8 differ from Example 1 in that the organic solvent in the preparation step of bis(trifluoromethyl)sulfide was changed, and the reaction temperature and reaction time were adjusted. The reaction results are shown in Table 1.
[0043] Comparative Examples 1-3:
[0044] Unlike Example 1, the preparation steps of bis(trifluoromethyl) sulfide in Comparative Example 1 were carried out in the absence of organic solvents; the preparation steps of bis(trifluoromethyl) sulfide in Comparative Example 2 were carried out in the absence of organic solvents and composite catalysts; and the preparation steps of bis(trifluoromethyl) sulfide in Comparative Example 3 were carried out in the absence of composite catalysts.
[0045] The specific results are shown in Table 1.
[0046] Table 1
[0047]
[0048]
[0049] 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 the method... include: Between 0 and 50 o In the presence of C and the composite catalyst and a protic acid, the cracked gas reacts with trifluoromethylthiocyanate in an organic solvent. The reactant gas produced during the reaction is cooled and the product is recovered via a condenser; the temperature of the condenser is -30 ~ 10°C. o C, the cooling temperature is lower than the temperature of the condenser tube; the protic acid is tetrafluoroboric acid, hexafluorophosphate or pentafluoroantimonic acid; the trifluoromethylthio salt is trifluoromethylthiotetramethylammonium, trifluoromethylthio(2,2'-bipyridine)copper or trifluoromethylthiosilver; The pyrolysis gas is a reaction of tetrafluoroethylene and sulfur at a reaction temperature of 400-600°C. o Gas produced by the pyrolysis reaction under C conditions; The composite catalyst is a mixture of crown ether and alkali metal bromide; the crown ether is diphenylpropyl 18-crown-6 ether, 15-crown-5 ether or benzo[18-crown-6 ether]; the alkali metal bromide is NaBr or KBr.
2. The method for preparing bis(trifluoromethyl) sulfide according to claim 1, characterized in that, The cooling recovery is carried out in a dry ice bath.
3. The method for preparing bis(trifluoromethyl)sulfide according to claim 1, characterized in that, The composite catalyst is a mixture of 15-crown 5-ether and NaBr, a mixture of benzo-18-crown 6-ether and KBr, or a mixture of dibenzo-18-crown 6-ether and KBr.
4. The method for preparing bis(trifluoromethyl)sulfide according to claim 1, characterized in that, The organic solvent is tetrahydrofuran, ethylene glycol dimethyl ether, dimethylformamide, dimethylacetamide, or dimethylthioformamide.
5. The method for preparing bis(trifluoromethyl)sulfide according to claim 1, characterized in that, The method for preparing the pyrolysis gas includes: heating sulfur to 400-600°C in a fixed-bed reactor. o C, then tetrafluoroethylene gas is introduced to react and produce cracked gas.
6. The method for preparing bis(trifluoromethyl)sulfide according to claim 1, characterized in that, The reaction time between the cracked gas and the trifluoromethylthiocyanate is 1 h to 5 h.
7. The method for preparing bis(trifluoromethyl)sulfide according to claim 1, characterized in that, The mass ratio of the composite catalyst to trifluoromethyl sulfide is 0.1~0.8:1.