A method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol

Abstract

The invention discloses a method for directly catalytically synthesizing dimethyl sulfide by sulfur, hydrogen and methanol. The catalyst used in the method is composed of an active component and a carrier, the active component is M1-K2O-M2, the carrier is γ-Al2O3, the CoO content in the catalyst is 2.5-4.8 wt%, the NiO content is 3.0-5.0 wt%, the K2O content is 0.3-0.5 wt%, and the MoO3 or WO3 is 12.0-15.0 wt%; the catalyst is placed in a fixed bed reactor, first the catalyst is vulcanized, hydrogen is introduced, the catalyst bed is heated, sulfur vapor is introduced, the vulcanization temperature is programmed to increase, vulcanization is performed, then the temperature is lowered, methanol vapor is introduced, dimethyl sulfide is catalytically synthesized, and the hydrogen space velocity is maintained at 300h ‑1 The reaction product is collected by freezing using a gas-liquid separator, and the selectivity of dimethyl sulfide is 96.4% to 98.5%.

Description

Technical Field

[0001] The invention belongs to the field of dimethyl sulfide synthesis and relates to a method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol. Background Art

[0002] Dimethyl sulfide is a colorless, transparent, volatile liquid at room temperature. It is flammable, explosive, highly toxic, and has an unpleasant odor. It is soluble in ethanol and ether, but insoluble in water. The relative density is 0.845, the flash point is -17.8℃, the melting point is -83℃, the boiling point is 37.5℃, and the refractive index is 1.4438. Dimethyl sulfide is an intermediate in the production of dimethyl sulfoxide, methionine, and pesticides. It can be used as a solvent for organic synthesis, polymerization, and cyanidation reactions. It is used for analytical tests, spinning of polyacrylonitrile and other synthetic fibers, and hydraulic oils. It can also be used as an odorizer for city gas, an industrial purifier, a paint stripping agent, a battery low-temperature preservative, a pesticide penetrant, etc. It is used topically in blood medicines, plant pathology, and nutrition. Low concentrations of dimethyl sulfide vapor generally cause nausea and loss of appetite, while high concentrations of vapor have a paralyzing effect on the central nervous system. Keep away from heat sources, prevent fire, and prevent explosion during storage and transportation. Store and transport in accordance with the regulations for flammable and toxic chemicals.

[0003] At present, there are three main methods for preparing dimethyl sulfide. The first is the synthesis method from methanol and carbon disulfide. The raw materials used in this method are highly toxic and irritating. Long-term production will cause serious damage to the health of employees and the surrounding ecological environment. The second is the reaction method of dimethyl sulfate and sodium sulfide. The main disadvantage of this method is that the raw materials are relatively expensive, the production cost is high, and the reaction yield is relatively low. It is not the best synthesis method for producing dimethyl sulfide. The third is the catalytic dehydration method of methanol and hydrogen sulfide. The raw material hydrogen sulfide in this method is highly toxic, relatively expensive, and has a high production cost. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for directly catalytically synthesizing dimethyl sulfide by sulfur, hydrogen and methanol. The present invention uses sulfur, hydrogen and methanol to catalytically synthesize dimethyl sulfide, avoids the use of highly toxic raw materials, has low raw material costs, and has a simple process flow, which can not only increase the economic benefits of the enterprise, but also has significant environmental benefits. The present invention directly catalytically synthesizes dimethyl sulfide by sulfur, hydrogen and methanol, avoiding the use of toxic gas hydrogen sulfide.

[0005] The technical solution of the present invention is as follows.

[0006] A method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol comprises the following steps: placing a catalyst in a fixed bed reactor, firstly sulfiding the catalyst, introducing hydrogen, heating the catalyst bed to 350-380°C, introducing sulfur vapor, raising the sulfidation temperature to 500-550°C, maintaining the sulfidation temperature at 500-550°C, and sulfidation time of 120-150 minutes, and then ending the sulfidation; cooling the temperature to 380-400°C, introducing methanol vapor, and catalytically synthesizing dimethyl sulfide.

[0007] The space velocity of hydrogen in the present invention is controlled at 300h -1 ~330h -1 , preferably 300h -1 .

[0008] The catalyst used in the method of the present invention consists of an active component and a carrier, the active component is M1-K2O-M2, wherein M1 is CoO or NiO, M2 is MoO3 or WO3, the carrier is γ-Al2O3, the CoO content in the catalyst is 2.5-4.8wt%, the NiO content is 3.0-5.0wt%, the K2O content is 0.3-0.5wt%, and the MoO3 or WO3 is 12.0-15.0wt%.

[0009] The preparation method of the catalyst is:

[0010] First, the precursor of CoO or NiO is dissolved in water, and ethylenediamine and potassium acetate are added to form a uniform solution; then the precursor of MoO3 or WO3 is dissolved in water; the two solutions are mixed, and then loaded on γ-Al2O3 by impregnation method, dried at 120℃~140℃ (preferably 120℃) for 4 hours to 5 hours, and then calcined at 550℃~580℃ for 4 hours to 5 hours (preferably calcined at 550℃ for 4 hours) to prepare the catalyst. In the laboratory, the reaction product is frozen and collected by gas-liquid separator, and then analyzed by gas chromatography.

[0011] The precursor of CoO or NiO described in the present invention is selected from cobalt nitrate hexahydrate or nickel nitrate hexahydrate.

[0012] The precursor of K2O described in the present invention is selected from potassium acetate.

[0013] The precursor of MoO3 or WO3 described in the present invention is selected from ammonium heptamolybdate or ammonium metatungstate. The catalyst needs to be sulfurized before use, and the sulfurization directly uses hydrogen and sulfur to sulfurize the catalyst.

[0014] In the present invention, the conversion rate of raw material hydrogen is 100%, the conversion rate of methanol is 100%, the conversion rate of sulfur is 99.8%, and the selectivity of dimethyl sulfide is 96.4% to 98.5%.

[0015] Compared with the prior art, the advantages of the present invention are:

[0016] (1) The present invention uses sulfur, hydrogen and methanol to catalyze the synthesis of dimethyl sulfide, avoiding the use of highly toxic raw materials, and has low raw material costs and a simple process flow, which can not only increase the economic benefits of the enterprise, but also have significant environmental benefits.

[0017] (2) The catalyst prepared by the present invention adopts a simple and effective method to effectively catalyze the synthesis of dimethyl sulfide. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with specific embodiments, but the embodiments of the present invention are not limited thereto. For process parameters not particularly noted, conventional techniques may be used.

[0019] Example 1

[0020] Dissolve 16.40g of Ni(NO3)2·6H2O in appropriate amount of water, add 3.39g of ethylenediamine and 0.95g of potassium acetate to form a uniform solution; weigh 18.06g of ammonium heptamolybdate and dissolve it in appropriate amount of water; then mix the above two solutions evenly, load them on 100g of γ-Al2O3 by impregnation method, dry at 120°C for 4 hours, and then calcine at 550°C for 4 hours to obtain a catalyst.

[0021] Example 2

[0022] Dissolve 18.25g of Co(NO3)2·6H2O in appropriate amount of water, add 3.77g of ethylenediamine and 1.16g of potassium acetate to form a uniform solution; weigh 19.42g of ammonium heptamolybdate and dissolve it in appropriate amount of water; then mix the above two solutions evenly, load them on 100g of γ-Al2O3 by impregnation method, dry at 120°C for 4 hours, and then calcine at 550°C for 4 hours to obtain a catalyst.

[0023] Example 3

[0024] Dissolve 20.36g of Ni(NO3)2·6H2O in appropriate amount of water, add 4.21g of ethylenediamine and 1.20g of potassium acetate to form a uniform solution; weigh 19.86g of ammonium metatungstate and dissolve it in appropriate amount of water; then mix the above two solutions evenly, load them on 100g of γ-Al2O3 by impregnation method, dry at 120°C for 4 hours, and then calcine at 550°C for 4 hours to obtain a catalyst.

[0025] Example 4

[0026] Dissolve 22.54g of Co(NO3)2·6H2O in appropriate amount of water, add 4.65g of ethylenediamine and 1.28g of potassium acetate to form a uniform solution; weigh 20.48g of ammonium metatungstate and dissolve it in appropriate amount of water; then mix the above two solutions evenly, load them on 100g of γ-Al2O3 by impregnation method, dry at 120℃ for 4 hours, and then calcine at 550℃ for 4 hours to obtain a catalyst.

[0027] Example 5

[0028] 10 ml (catalyst loading by volume) of the catalyst obtained in Example 1 was loaded into a reaction tube. The catalyst was first vulcanized by introducing hydrogen, heating the catalyst bed to 350°C, introducing sulfur vapor, and program-raising the vulcanization temperature to 500°C. The vulcanization temperature was maintained at 500°C for 120 min, and then the vulcanization was terminated. The temperature was lowered to 380°C to 400°C, methanol vapor was introduced, and dimethyl sulfide was catalytically synthesized. The hydrogen space velocity was maintained at 300 h / min. -1 The reaction products were collected by freezing using a gas-liquid separator. Chromatographic analysis showed that both hydrogen and methanol were completely converted, and the selectivity of dimethyl sulfide was 97.5%.

[0029] Example 6

[0030] 10 ml of the catalyst obtained in Example 2 was loaded into a reaction tube. The catalyst was first vulcanized by introducing hydrogen, heating the catalyst bed to 350°C, introducing sulfur vapor, and program-raising the vulcanization temperature to 500°C. The vulcanization temperature was maintained at 500°C for 120 min, and then the vulcanization was terminated. The temperature was lowered to 380°C to 400°C, and methanol vapor was introduced to catalyze the synthesis of dimethyl sulfide. The hydrogen space velocity was maintained at 300 h / min. -1 The reaction products were collected by freezing using a gas-liquid separator. Chromatographic analysis showed that both hydrogen and methanol were completely converted, and the selectivity of dimethyl sulfide was 97.8%.

[0031] Example 7

[0032] 10 ml of the catalyst obtained in Example 3 was loaded into a reaction tube. The catalyst was first sulfurized by introducing hydrogen, heating the catalyst bed to 350°C, introducing sulfur vapor, and program-raising the sulfurization temperature to 500°C. The sulfurization temperature was maintained at 500°C for 120 min, and then the sulfurization was terminated. The temperature was lowered to 380°C to 400°C, and methanol vapor was introduced to catalyze the synthesis of dimethyl sulfide. The hydrogen space velocity was maintained at 300 h / min. -1 The reaction products were collected by freezing using a gas-liquid separator. Chromatographic analysis showed that both hydrogen and methanol were completely converted, and the selectivity of dimethyl sulfide was 98.5%.

[0033] Example 8

[0034] 10 ml of the catalyst obtained in Example 4 was loaded into a reaction tube. The catalyst was first vulcanized by introducing hydrogen, heating the catalyst bed to 350°C, introducing sulfur vapor, and program-raising the vulcanization temperature to 500°C. The vulcanization temperature was maintained at 500°C for 120 min, and then the vulcanization was terminated. The temperature was lowered to 380°C to 400°C, and methanol vapor was introduced to catalyze the synthesis of dimethyl sulfide. The hydrogen space velocity was maintained at 300 h / min. -1 The reaction products were collected by freezing using a gas-liquid separator. Chromatographic analysis showed that both hydrogen and methanol were completely converted, and the selectivity of dimethyl sulfide was 98.2%.

[0035] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol, characterized in that: The catalyst is placed in a fixed bed reactor, and the catalyst is firstly sulfurized by introducing hydrogen, heating the catalyst bed to 350°C-380°C, introducing sulfur vapor, and raising the sulfurization temperature to 500°C-550°C by program, and the sulfurization temperature is maintained at 500°C-550°C, and the sulfurization time is 120min-150min, and then the sulfurization is terminated; the temperature is lowered to 380°C-400°C, and methanol vapor is introduced to catalyze the synthesis of dimethyl sulfide; The catalyst used in this method consists of an active component and a carrier. The active component is M1-K2O-M2, wherein M1 is CoO or NiO, M2 is MoO3 or WO3, the carrier is γ-Al2O3, the CoO content in the catalyst is 2.5~4.8 wt%, the NiO content is 3.0~5.0 wt%, the K2O content is 0.3~0.5 wt%, and the MoO3 or WO3 is 12.0~15.0 wt%.

2. The method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol as claimed in claim 1, characterized in that: The preparation method of the catalyst is: First, the precursor of CoO or NiO is dissolved in water, and ethylenediamine and potassium acetate are added to form a uniform solution; then the precursor of MoO3 or WO3 is dissolved in water; the two solutions are mixed, and then loaded on γ-Al2O3 by an impregnation method, dried at 120°C~140°C for 4 hours~5 hours, and then calcined at 550°C~580°C for 4 hours~5 hours to obtain a catalyst.

3. The method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol as claimed in claim 1, characterized in that: The hydrogen space velocity during the catalytic reaction was controlled at 300 h -1 ~330h -1 .

4. The method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol as claimed in claim 2, characterized in that: The precursor of CoO or NiO is selected from cobalt nitrate hexahydrate or nickel nitrate hexahydrate.

5. The method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol as claimed in claim 2, characterized in that: The precursor of K2O is selected from potassium acetate.

6. The method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol as claimed in claim 1, characterized in that: The catalyst carrier is selected from γ-Al2O3.

7. The method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol as claimed in claim 1, characterized in that: The precursor of MoO3 or WO3 is selected from ammonium heptamolybdate or ammonium metatungstate.

8. The method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol as claimed in claim 1, characterized in that: The catalyst needs to be sulfurized before use, and the sulfurization directly uses hydrogen and sulfur to sulfurize the catalyst.

9. The method for directly catalytically synthesizing dimethyl sulfide from sulfur, hydrogen and methanol as claimed in claim 1, characterized in that: The conversion rate of raw hydrogen is 100%, the conversion rate of methanol is 100%, the conversion rate of sulfur is 99.8%, and the selectivity of dimethyl sulfide is 96.4% to 98.5%.