A process for the preparation of alkyl mercaptans from alpha-olefins
By loading 1-methyl-3-(3-alkoxysilylpropyl)imidazolium acidic ionic liquid onto fumed silica to form a catalyst, the problems of insufficient catalyst stability and selectivity in the prior art are solved, and efficient alkyl thiols are produced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-12-02
- Publication Date
- 2026-06-02
AI Technical Summary
In the prior art, sulfonic acid resin catalysts such as Amberlyst-15 have poor stability in the reaction of α-olefins with hydrogen sulfide, while molecular sieve catalysts have better stability but poor catalytic activity and selectivity.
A 1-methyl-3-(3-alkoxysilylpropyl)imidazolium acidic ionic liquid was generated by reacting 1-methylimidazolium with 3-chloropropyltrialkoxysilane, and then supported on fumed silica to form a fumed silica-supported acidic ionic liquid catalyst for the reaction of α-olefins with hydrogen sulfide.
This improved the stability and catalytic activity of the catalyst, enhanced the selectivity of alkyl thiols, and enabled efficient production of alkyl thiols.
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Abstract
Description
Technical Field
[0001] This application relates to a method for preparing alkyl thiols from α-olefins, belonging to the field of xx. Background Technology
[0002] Alkyl mercaptans are important chemicals used as polymerization regulators in synthetic rubber, synthetic fibers, and synthetic resins. They are also used in the production of polyvinyl chloride stabilizers, pharmaceuticals, pesticides, fungicides, and detergents. Alkyl mercaptans can be produced by reacting α-olefins with hydrogen sulfide using sulfonic acid resins such as Amberlyst-15 as catalysts. However, because this reaction is strongly exothermic, catalysts such as Amberlyst-15 are unstable under the reaction conditions, and the sulfonic acid groups in them easily decompose upon heating, leading to catalyst deactivation. Molecular sieves and other catalysts have better stability, but their catalytic activity and selectivity are inferior.
[0003] Alkyl mercaptans are important chemicals used as polymerization regulators in synthetic rubber, synthetic fibers, and synthetic resins. They are also used in the production of polyvinyl chloride stabilizers, pharmaceuticals, pesticides, fungicides, and detergents. Alkyl mercaptans can be produced by reacting α-olefins with hydrogen sulfide using sulfonic acid resins such as Amberlyst-15 as catalysts. However, because this reaction is strongly exothermic, catalysts such as Amberlyst-15 are unstable under the reaction conditions, and the sulfonic acid groups in them easily decompose upon heating, leading to catalyst deactivation. Molecular sieves and other catalysts have better stability, but their catalytic activity and selectivity are inferior. Summary of the Invention
[0004] To address the current problems of poor stability of sulfonic acid resin catalysts such as Amberlyst-15 and the relatively good stability but poor catalytic activity and selectivity of molecular sieve catalysts in the reaction of α-olefins with hydrogen sulfide to prepare alkyl mercaptans, this application provides a method for preparing alkyl mercaptans by reacting α-olefins with hydrogen sulfide, which has the advantages of good catalyst stability, high catalytic activity and selectivity.
[0005] According to one aspect of this application, a method for preparing alkyl thiols from α-olefins is provided, characterized in that...
[0006] Includes the following steps:
[0007] In a reactor, α-olefins and hydrogen sulfide are contacted with a catalyst to react in reaction I, yielding alkyl thiols;
[0008] The α-olefin is selected from at least one of the α-olefins of C6 to C16;
[0009] The catalyst is obtained through the following steps:
[0010] S1) 1-Methylimidazolium is mixed with 3-chloropropyltrialkoxysilane and reacted in reaction II to give 1-methyl-3-(3-alkoxysilylpropyl)imidazolium chloride;
[0011] S2) Mix 1-methyl-3-(3-alkoxysilylpropyl)imidazolium chloride with acid and react in reaction III to obtain 1-methyl-3-(3-alkoxysilylpropyl)imidazolium acidic ionic liquid;
[0012] S3) Mix 1-methyl-3-(3-alkoxysilylpropyl)imidazolium acidic ionic liquid, fumed silica and solvent, and react for IV to obtain an acidic ionic liquid catalyst supported on fumed silica, which is the catalyst.
[0013] The 3-chloropropyltrialkoxysilane is selected from at least one of 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane;
[0014] The acid is selected from at least one of sulfuric acid and phosphoric acid;
[0015] The solvent is selected from at least one of toluene, ethylbenzene, and xylene.
[0016] The molar ratio of 1-methylimidazolium to 3-chloropropyltrialkoxysilane is 1:1 to 1.1:1;
[0017] Optionally, the molar ratio of 1-methylimidazole to 3-chloropropyltrialkoxysilane is independently selected from any value of 1:1, 1.02:1, 1.04:1, 1.06:1, 1.08:1, 1.1:1 or any range between the two.
[0018] The temperature of reaction II is 50–100°C;
[0019] Optionally, the reaction temperature of reaction II is independently selected from any value of 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, or a range between any two.
[0020] The reaction time for reaction II is 8–24 hours.
[0021] Optionally, the reaction time of reaction II is independently selected from any value of 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h or a range between any two.
[0022] The molar ratio of the acid to 1-methyl-3-(3-alkoxysilylpropyl)imidazolium chloride is 1:1 to 1.1:1;
[0023] Optionally, the molar ratio of the acid to 1-methyl-3-(3-alkoxysilylpropyl)imidazolium chloride is independently selected from any value of 1:1, 1.02:1, 1.04:1, 1.06:1, 1.08:1, 1.1:1 or any range between both.
[0024] The temperature of reaction III is 20–60°C;
[0025] Optionally, the reaction temperature of reaction III is independently selected from any value of 20°C, 30°C, 40°C, 50°C, 60°C, or a range between any two.
[0026] The reaction time for reaction III is 8–24 hours.
[0027] Optionally, the reaction time of reaction III is independently selected from any value of 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h or a range between any two.
[0028] The mass ratio of the 1-methyl-3-(3-alkoxysilylpropyl)imidazolium acidic ionic liquid to fumed silica is 1:2 to 1:4.
[0029] Optionally, the mass ratio of the 1-methyl-3-(3-alkoxysilylpropyl)imidazolium acidic ionic liquid to fumed silica is independently selected from any value of 1:2, 1:2.5, 1:3, 1:3.5, 1:4 or any range between the two.
[0030] The mass ratio of the fumed silica to the solvent is 1:2 to 1:4.
[0031] The reaction temperature of reaction IV is 100–140°C;
[0032] Optionally, the reaction temperature of reaction IV is independently selected from any value of 100°C, 110°C, 120°C, 130°C, 140°C, or a range between any two.
[0033] The reaction time for IV is 8–24 hours.
[0034] Optionally, the reaction time of reaction IV is independently selected from any value of 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h or a range between any two.
[0035] The volume hourly space velocity (VHSV) of the α-olefin is 0.5–2 h⁻¹. -1 ;
[0036] Optionally, the volume hourly space velocity of the α-olefin is independently selected from 0.5 h⁻¹. -1 0.7h-1 1h -1 1.2h -1 1.5h -1 1.8h -1 2h -1 Any value in or a range between any two;
[0037] The molar ratio of hydrogen sulfide to α-olefin is 1:1 to 5:1.
[0038] Optionally, the molar ratio of hydrogen sulfide to α-olefin is independently selected from any value of 1:1, 2:1, 3:1, 4:1, 5:1 or any range between two.
[0039] The temperature of reaction I is 50–80°C;
[0040] Optionally, the reaction temperature of reaction I is independently selected from any value of 50°C, 60°C, 70°C, 80°C, or any range between two of them;
[0041] The pressure of reaction I is 0.5–1 MPa.
[0042] Optionally, the reaction pressure of reaction I is independently selected from any value of 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa, or a range between any two.
[0043] The beneficial effects that this application can produce include:
[0044] To address the problems of poor stability of sulfonic acid resin catalysts such as Amberlyst-15 and the relatively good stability but poor catalytic activity and selectivity of molecular sieve catalysts in the reaction of α-olefins with hydrogen sulfide to prepare alkyl mercaptans, this application provides a method for preparing alkyl mercaptans by reacting α-olefins with hydrogen sulfide, which has the advantages of good catalyst stability, high catalytic activity and selectivity. Detailed Implementation
[0045] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0046] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0047] Unless otherwise specified, all testing methods shall be conventional.
[0048] In the embodiments of this application, the conversion rate and yield are calculated as follows:
[0049]
[0050] This application uses an Agilent Technologies 7890A-5975C gas chromatography-mass spectrometry (GC-MS) instrument to determine olefin conversion and alkyl thiol yield.
[0051] Example 1
[0052] 8.2 g (0.1 mol) of 1-methylimidazolium and 24.1 g (0.1 mol) of 3-chloropropyltriethoxysilane were mixed and reacted at 100 °C for 8 h to obtain 32.3 g (0.1 mol) of 1-methyl-3-(3-ethoxysilylpropyl)imidazolium chloride. 10.0 g (0.1 mol) of 98% concentrated sulfuric acid was added to the mixture, and the reaction was carried out at 60 °C for 8 h to obtain 38.5 g of 1-methyl-3-(3-ethoxysilylpropyl)imidazolium-sulfuric acidic ionic liquid. 77.0 g of fumed silica and 154.0 g of toluene were added to the mixture, and the reaction was carried out at 100 °C for 24 h. The mixture was filtered, washed with ethanol, and dried to obtain 101.5 g of fumed silica-supported imidazolium-sulfuric acidic ionic liquid catalyst I.
[0053] Example 2
[0054] 9.0 g (0.11 mol) of 1-methylimidazolium and 19.9 g (0.1 mol) of 3-chloropropyltrimethoxysilane were mixed and reacted at 50 °C for 24 h to obtain 28.1 g (0.1 mol) of 1-methyl-3-(3-methoxysilylpropyl)imidazolium chloride. 12.7 g (0.11 mol) of 85% concentrated phosphoric acid was added to the mixture, and the reaction was carried out at 20 °C for 24 h to obtain 34.2 g of 1-methyl-3-(3-methoxysilylpropyl)imidazolium-phosphoric acidic ionic liquid. 136.8 g of fumed silica and 547.2 g of xylene were added to the mixture, and the reaction was carried out at 140 °C for 8 h. The mixture was filtered, washed with ethanol, and dried to obtain 156.6 g of fumed silica-supported imidazolium-phosphoric acidic ionic liquid catalyst II.
[0055] Example 3
[0056] 8.6 g (0.105 mol) of 1-methylimidazolium and 24.1 g (0.1 mol) of 3-chloropropyltriethoxysilane were mixed and reacted at 80 °C for 16 h to obtain 32.3 g (0.1 mol) of 1-methyl-3-(3-ethoxysilylpropyl)imidazolium chloride. 10.5 g (0.105 mol) of 98% concentrated sulfuric acid was added to the mixture, and the reaction was carried out at 40 °C for 16 h to obtain 38.5 g of 1-methyl-3-(3-ethoxysilylpropyl)imidazolium-sulfuric acidic ionic liquid. 115.5 g of fumed silica and 346.5 g of ethylbenzene were added to the mixture, and the reaction was carried out at 120 °C for 16 h. The mixture was filtered, washed with ethanol, and dried to obtain 139.7 g of fumed silica-supported imidazolium-sulfuric acidic ionic liquid catalyst III.
[0057] Example 4
[0058] 20g of the fumed silica-supported imidazole-sulfuric acidic ionic liquid catalyst I prepared in Example 1 was loaded into a reaction tube, and 1-dodecene and hydrogen sulfide were pumped in. The volume hourly space velocity (VHSV) of 1-dodecene was 0.5 h⁻¹. -1 The molar ratio of hydrogen sulfide to 1-dodecene was 3:1, the reaction temperature was 80℃, and the reaction pressure was 0.7 MPa. After the reaction was continuously run for 4 hours, samples were taken and analyzed by gas chromatography-mass spectrometry. The conversion rate of 1-dodecene was 96%, and the yield of dodecyl mercaptan was 95%. After the reaction was continuously run for 24 hours, samples were taken again for analysis, and the conversion rate of 1-dodecene was 96%, and the yield of dodecyl mercaptan was 95%.
[0059] Example 5
[0060] 20g of the fumed silica-supported imidazole-phosphoric acidic ionic liquid catalyst II prepared in Example 2 was loaded into a reaction tube, and 1-hexene and hydrogen sulfide were pumped in. The volume hourly space velocity (VHSV) of 1-hexene was 2 h⁻¹. -1 The molar ratio of hydrogen sulfide to 1-hexene was 5:1, the reaction temperature was 50℃, and the reaction pressure was 1 MPa. After the reaction was continuously run for 4 hours, samples were taken and analyzed by gas chromatography-mass spectrometry. The conversion rate of 1-hexene was 95%, and the yield of hexamethylene mercaptan was 94%. After the reaction was continuously run for 24 hours, samples were taken again for analysis, and the conversion rate of 1-hexene was 95%, and the yield of hexamethylene mercaptan was 94%.
[0061] Example 6
[0062] 20g of the fumed silica-supported imidazole-sulfuric acidic ionic liquid catalyst III prepared in Example 3 was loaded into a reaction tube, and 1-hexadecene and hydrogen sulfide were pumped in. The volume hourly space velocity (VHSV) of 1-hexadecene was 1 h⁻¹. -1 The molar ratio of hydrogen sulfide to 1-hexadecene was 1:1, the reaction temperature was 70℃, and the reaction pressure was 0.5 MPa. After the reaction was continuously run for 4 hours, samples were taken and analyzed by gas chromatography-mass spectrometry. The conversion rate of 1-hexadecene was 91%, and the yield of hexadecene mercaptan was 90%. After the reaction was continuously run for 24 hours, samples were taken again for analysis, and the conversion rate of 1-hexadecene was 91%, and the yield of hexadecene mercaptan was 90%.
[0063] Comparative Example 1
[0064] The difference between Comparative Example 1 and Example 1 is that 10.0 g (0.1 mol) of 98% concentrated sulfuric acid was not added during the reaction process, while other conditions were the same as in Example 1, and 92.1 g of fumed silica-supported imidazole-chloride ion liquid catalyst IV was finally obtained.
[0065] Comparative Example 2
[0066] The difference between Comparative Example 2 and Example 1 is that 200-300 mesh silica gel was used instead of fumed silica, while other conditions were the same as in Example 1, and 90.2 g of silica gel-supported imidazole-sulfuric acidic ionic liquid catalyst V was finally obtained.
[0067] Comparative Example 3
[0068] The difference between Comparative Example 3 and Example 4 is that the fumed silica-supported imidazole-chloride ionic liquid catalyst IV prepared in Comparative Example 1 was used instead of the fumed silica-supported imidazole-sulfuric acid ionic liquid catalyst I prepared in Example 1. All other conditions were the same as in Example 4. After 4 hours of continuous reaction, the conversion rate of 1-dodecene was 8%, and the yield of dodecyl mercaptan was 7%. After 24 hours of continuous reaction, samples were taken again for analysis, and the conversion rate of 1-dodecene was 8%, and the yield of dodecyl mercaptan was 7%.
[0069] Comparative Example 4
[0070] The difference between Comparative Example 4 and Example 4 is that the silica-supported imidazole-sulfuric acid ionic liquid catalyst V prepared in Comparative Example 2 was used instead of the fumed silica-supported imidazole-sulfuric acid ionic liquid catalyst I prepared in Example 1. All other conditions were the same as in Example 4. After 4 hours of continuous reaction, the conversion rate of 1-dodecene was 30%, and the yield of dodecyl mercaptan was 29%. After 24 hours of continuous reaction, samples were taken again for analysis, and the conversion rate of 1-dodecene was 30%, and the yield of dodecyl mercaptan was 29%.
[0071] Comparative Examples 3 and 4 show that the catalyst has a significant impact on the reaction results. In Comparative Example 3, using an imidazole-chloride ionic liquid catalyst supported on fumed silica instead of an imidazole acidic liquid catalyst supported on fumed silica, the conversion rate of 1-dodecene was only 8%. In Comparative Example 4, using an imidazole-sulfuric acidic ionic liquid catalyst supported on ordinary silica gel, the conversion rate of 1-dodecene was only 30%. This may be because the 200-300 mesh ordinary silica gel particles are relatively large, resulting in poor contact with the 1-methyl-3-(3-ethoxysilylpropyl)imidazole-sulfuric acidic ionic liquid, leading to less active component supported on the silica gel, and thus lower catalyst activity.
[0072] In summary, this application addresses the problems of poor stability of sulfonic acid resin catalysts such as Amberlyst-15 and the relatively good stability of molecular sieve catalysts in the reaction of α-olefins with hydrogen sulfide to prepare alkyl mercaptans. It provides a method for preparing alkyl mercaptans by reacting α-olefins with hydrogen sulfide, which has the advantages of good catalyst stability, high catalytic activity and selectivity.
[0073] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for preparing alkyl thiols from α-olefins, characterized in that, Includes the following steps: In a reactor, α-olefins and hydrogen sulfide are contacted with a catalyst to react in reaction I, yielding alkyl thiols; The α-olefin is selected from at least one of the α-olefins of C6 to C16; The catalyst is obtained through the following steps: S1) 1-Methylimidazolium is mixed with 3-chloropropyltrialkoxysilane and reacted in reaction II to give 1-methyl-3-(3-alkoxysilylpropyl)imidazolium chloride; S2) Mix 1-methyl-3-(3-alkoxysilylpropyl)imidazolium chloride with acid and react in reaction III to obtain 1-methyl-3-(3-alkoxysilylpropyl)imidazolium acidic ionic liquid; S3) Mix 1-methyl-3-(3-alkoxysilylpropyl)imidazolium acidic ionic liquid, fumed silica and solvent, and react for IV to obtain an acidic ionic liquid catalyst supported on fumed silica, which is the catalyst.
2. The method according to claim 1, characterized in that, The 3-chloropropyltrialkoxysilane is selected from at least one of 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane; The acid is selected from at least one of sulfuric acid and phosphoric acid; The solvent is selected from at least one of toluene, ethylbenzene, and xylene.
3. The method according to claim 1, characterized in that, The molar ratio of 1-methylimidazolium to 3-chloropropyltrialkoxysilane is 1:1 to 1.1:1; The temperature of reaction II is 50–100°C; The reaction time for reaction II is 8–24 hours.
4. The method according to claim 1, characterized in that, The molar ratio of the acid to 1-methyl-3-(3-alkoxysilylpropyl)imidazolium chloride is 1:1 to 1.1:1; The temperature of reaction III is 20–60°C; The reaction time for reaction III is 8–24 hours.
5. The method according to claim 1, characterized in that, The mass ratio of the 1-methyl-3-(3-alkoxysilylpropyl)imidazolium acidic ionic liquid to fumed silica is 1:2 to 1:
4. The mass ratio of the fumed silica to the solvent is 1:2 to 1:
4. The reaction temperature of reaction IV is 100–140°C; The reaction time for IV is 8–24 hours.
6. The method according to claim 1, characterized in that, The volume hourly space velocity (VHSV) of the α-olefin is 0.5–2 h⁻¹. -1 ; The molar ratio of hydrogen sulfide to α-olefin is 1:1 to 5:
1.
7. The method according to claim 1, characterized in that, The temperature of reaction I is 50–80°C; The pressure of reaction I is 0.5–1 MPa.