Preparation method of squalane
By using Pd/SiO2 catalyst to convert squalene to squalene under normal pressure, the problem of pressurization in the preparation of squalene in the prior art is solved, and an efficient and safe preparation process is achieved, and the product purity and yield are also significantly improved.
Patent Information
- Application Number
- CN202311832977.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2025-07-01
AI Technical Summary
The preparation of existing squalane needs to be carried out under pressurized conditions, resulting in complex operation.
Under H2 conditions, in the presence of Pd/SiO2 catalyst, an atmospheric reaction was carried out to convert squalene to squalene. Pd/SiO2 is prepared by the synthesis method of silicon and palladium sources and is used as a catalyst for hydrogenation reaction.
It realizes efficient preparation of squalane under normal pressure, which is easy to operate and safe, has high reaction yield and high product purity, and solves the complexity of pressurized operation.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a method for preparing squalane. Background Art
[0002] Squalane is a colorless and transparent liquid, an alkane with C 30 H 62 Squalane is the common name of isotriacontane and is the hydrogenation product of docosahexaenoic acid (common name squalene). Docosahexaenoic acid exists in the liver of sharks and human sebum. In the past, docosahexaenoic acid has been extracted from the liver of sharks in industry, and squalene and squalane got their names from this. Although in the early 1950s, O. Isler, R. Riiegg and others reported methods for preparing squalene from nerolidol, industrial total synthesis of squalane did not occur until after the 1970s. Since squalene is very sensitive to light, heat and oxygen, its hydrogenation product, squalane, is used industrially.
[0003] According to literature reports, the synthesis of squalane can be summarized into two aspects: one is to use organic intermediates (such as tetraene diol, etc.) obtained by chemical synthesis methods as raw materials, and carry out catalytic hydrogenation under medium pressure, high temperature and Pd / C catalyst to obtain squalane; the other is to use squalene obtained by physical and chemical processing of vegetable oils (such as olive oil, birch oil, white pine oil, etc.) as raw materials, and carry out catalytic hydrogenation under Pd / C catalyst to obtain squalane. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to overcome the defect that the existing preparation of squalane needs to be carried out under pressurized conditions, resulting in complex operations. The present invention provides a method for preparing squalane. The preparation method of the present invention has simple, safe and efficient operation steps, does not require pressurization, has a high reaction yield, and the obtained product has a high purity.
[0005] The present invention solves the above technical problems through the following solutions.
[0006] The present invention provides a method for preparing squalane, which includes the following steps: under the condition of H2, in the presence of Pd / SiO2, squalene reacts to obtain squalane;
[0007]
[0008] In the described preparation method, the reaction can be carried out under normal pressure.
[0009] In the described preparation method, the Pd / SiO2 is gel-supported Pd / SiO2.
[0010] In the described preparation method, the mass ratio of the Pd / SiO2 to the squalene can be (4 - 10):100, preferably 4:100, 5:100 or 6:100; more preferably 4:100.
[0011] In the preparation method, the reaction can be carried out under solvent or solvent-free conditions.
[0012] In the preparation method, when the reaction is carried out under solvent conditions, the mass ratio of squalene to the solvent can be 1:3 to 1:6, preferably 1:5.
[0013] In the preparation method, the solvent can be an alcohol solvent; preferably, the alcohol solvent is selected from one or more of methanol, ethanol, and isopropanol.
[0014] In the preparation method, the temperature of the reaction can be 60 °C to 140 °C.
[0015] In the preparation method, the H2 can be replaced with H2 three times.
[0016] In the preparation method, the reaction includes filtering to obtain a filtrate after the reaction is completed; preferably, the filtering is carried out after cooling to room temperature; preferably, the filtering can be carried out using a 0.45 μm filter membrane.
[0017] In the preparation method, the Pd / SiO2 is prepared by the following preparation method: an ethanol solution of a silicon source is mixed with acetic acid and heated to remove ethanol. The resulting alcohol-free sol is mixed with an aqueous and acetonitrile solution of a palladium source, the pH is adjusted, and after ultrasonic dispersion and drying, it is reduced with a reducing agent in an organic solvent under an inert gas condition to obtain a Pd / SiO2 catalyst.
[0018] In the preparation method, the silicon source can be one or two of methyltriethoxysilane, tetraethoxysilane, and sodium silicate; preferably, methyltriethoxysilane.
[0019] In the preparation method, the palladium source can be one of KPdCl4, PdCl2, and Pd(OAc)2; preferably, KPdCl4.
[0020] In the preparation method, the molar ratio of the palladium source to the silicon source can be 0.004 to 0.02:1, preferably 0.01:1.
[0021] In the preparation method, the concentration of the silicon source in the ethanol solution can be 1 to 5 g / mL, preferably 2 g / mL.
[0022] In the preparation method, the volume ratio of acetic acid to ethanol can be 1:10.
[0023] In the preparation method, the pH adjustment is to adjust the pH to 7 to 8.
[0024] In the preparation method, the reducing agent can be sodium triacetoxyborohydride.
[0025] In the preparation method, the organic solvent may be tetrahydrofuran.
[0026] In the preparation method, the molar ratio of Pd to the reducing agent in the Pd / SiO2 may be 1:6.
[0027] The present invention also provides a method for preparing gel-supported Pd / SiO2, which includes the following steps: an ethanol solution of a silicon source is mixed with acetic acid and heated to remove ethanol. The resulting alcohol-free sol is mixed with an aqueous and acetonitrile solution of a palladium source, the pH is adjusted, and after ultrasonic dispersion and drying, it is reduced with a reducing agent in an organic solvent under an inert gas condition to obtain a Pd / SiO2 catalyst.
[0028] In the method for preparing the gel-supported Pd / SiO2, the reaction conditions of the preparation method are as described above.
[0029] In the present invention, room temperature refers to 20-30°C.
[0030] On the basis of not violating the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.
[0031] The reagents and raw materials used in the present invention are all commercially available.
[0032] The technical effects and advantages of the present invention are as follows:
[0033] (1) The novel gel-supported palladium catalyst Pd / SiO2 prepared by the present invention can catalytically hydrogenate squalene to prepare squalane under normal pressure, and the operation steps are simple, safe and efficient.
[0034] (2) The squalane content synthesized by this method can reach 90% - 98%, the reaction yield is high, the purity is high, the problem that squalene is difficult to hydrogenate under normal pressure is solved, the difficulty of hydrogenating squalane in synthesis is reduced, and a new method for preparing squalane by hydrogenating squalene is provided. Description of the Drawings
[0035] Figure 1 It is the GC spectrum of the filtrate after the reaction in Example 1. Detailed Embodiments
[0036] The present invention will be further illustrated by the following examples, but the present invention is not limited to the scope of the described examples. The experimental methods without specific conditions in the following examples are carried out according to conventional methods and conditions, or selected according to the product specifications.
[0037] Synthesis method:
[0038] Step (1) Preparation of Pd / SiO₂ catalyst. In the preparation of the catalyst, methyltriethoxysilane was dissolved in ethanol, and a small amount of acetic acid solution was added thereto, and heated and stirred to rapidly hydrolyze it. Then, KPdCl₄ (0.004 - 0.02 equivalents) dissolved in H₂O and acetonitrile was added to the alcohol-free sol obtained after rotary evaporation. A small amount of ammonia water was added to this mixture to adjust the pH, and then ultrasonic dispersion was carried out while gelling the solution. After the obtained transparent gel was completely dried in air, under inert gas conditions, the dry gel was reduced with sodium triacetoxyborohydride (Pd:STAB = 1:6 molar ratio) in THF solution. After filtration, it was washed with THF and H₂O and dried in air to obtain the gel-supported palladium catalyst - Pd / SiO₂.
[0039] Step (2) Preparation of squalane. In the hydrogenation of squalene under normal pressure, squalene was dissolved in an appropriate solvent, an appropriate amount of Pd / SiO₂ was added, and the air in the reaction flask was replaced with H₂ three times to ensure that the oxygen in the reaction flask was completely removed. The reaction was carried out at 60 °C - 140 °C for 6 h - 16 h. After the system was cooled and filtered, squalane was obtained. By GC-Mass detection, the squalane content was 90% - 98%.
[0040] Example 1
[0041] 20 g of methyltriethoxysilane was dissolved in 10 mL of ethanol solution, 1 mL of acetic acid was added thereto and heated, and stirred at 30 - 40 °C for 15 min and then rotary evaporated. KPdCl₄ (0.02 equivalents) dissolved in 5 mL of H₂O and 60 mL of acetonitrile was added to the obtained alcohol-free sol. A small amount of ammonia water was added to adjust the pH to 7 - 8, and then ultrasonic dispersion was carried out while gelling the solution. After the obtained transparent gel was completely dried in air at room temperature, under inert gas conditions, the dry gel was reduced with sodium triacetoxyborohydride (Pd:STAB = 1:6 molar ratio) in 80 mL of THF solution. After filtration, it was washed with THF and H₂O and dried in air to obtain the Pd / SiO₂ catalyst for the following catalytic experiments.
[0042] 1.0 g of squalene was taken in a 10 mL round-bottom flask, 50 mg of the prepared Pd / SiO₂ was added, and the air in the reaction flask was replaced with H₂ three times to ensure that the oxygen in the reaction flask was completely removed. The reaction was carried out at 130 °C for 6 h. After the system was cooled and filtered, squalane was obtained. By GC-Mass detection, the squalane content was 98% ( Figure 1 ).
[0043] Example 2
[0044] Take 4.0 g of squalene in a 50 mL round-bottom flask, add 240 mg of Pd / SiO2 and 20 g of absolute ethanol. Replace the gas with H2 three times to ensure that the oxygen in the reaction flask is completely removed. React at 80 °C under normal pressure for 10 h. After the system is cooled, filtered and concentrated, squalane is obtained. The content of squalane is 95% by GC-Mass detection.
[0045] Example 3
[0046] Take 10.0 g of squalene in a 100 mL round-bottom flask, add 400 mg of Pd / SiO2 and 50 g of absolute methanol. Replace the gas with H2 three times to ensure that the oxygen in the reaction flask is completely removed. React at 65 °C under normal pressure for 16 h. After the system is cooled, filtered and concentrated, squalane is obtained. The content of squalane is 96% by GC-Mass detection.
[0047] Example 4
[0048] Take 5.0 g of squalene in a 100 mL round-bottom flask, add 250 mg of Pd / SiO2 and 30 mL of isopropanol. Replace the gas with H2 three times to ensure that the oxygen in the reaction flask is completely removed. React at 80 °C under normal pressure for 12 h. After the system is cooled, filtered and concentrated, squalane is obtained. The content of squalane is 93% by GC-Mass detection.
Claims
1. A method for preparing squalane, characterized in that, It includes the following steps: Under H2 condition, in the presence of Pd / SiO2, squalene reacts to obtain squalane; 2. The preparation method according to claim 1, characterized in that, The reaction is carried out under atmospheric pressure.
3. The preparation method according to claim 1, characterized in that, The Pd / SiO2 is gel-supported Pd / SiO2; And / or, the mass ratio of the Pd / SiO2 to the squalene is (4 - 10):100, preferably 4:100, 5:100 or 6:100; more preferably 4:
100.
4. The preparation method according to claim 1, wherein The reaction is carried out under solvent or solvent-free conditions.
5. The preparation method according to claim 4, wherein, When the reaction is carried out under solvent conditions, the mass ratio of the squalene to the solvent is 1:3 to 1:6, preferably 1:5; And / or, the solvent is an alcohol solvent; preferably, the alcohol solvent is selected from one or more of methanol, ethanol and isopropanol.
6. The preparation method according to claim 1, characterized in that, The temperature of the reaction is 60°C to 140°C.
7. The preparation method according to claim 1, wherein, The Pd / SiO2 is prepared by the following preparation method: An ethanol solution of a silicon source is mixed with acetic acid and heated to remove ethanol. The resulting alcohol-free sol is mixed with an aqueous and acetonitrile solution of a palladium source, the pH is adjusted, and after ultrasonic dispersion and drying, in an organic solvent, under an inert gas condition, it is reduced by a reducing agent to obtain a Pd / SiO2 catalyst.
8. The preparation method according to claim 7, characterized in that, It satisfies one or more of the following conditions: (1) The silicon source is selected from one or more of methyltriethoxysilane, tetraethoxysilane and sodium silicate, preferably methyltriethoxysilane; (2) The palladium source is selected from one or more of KPdCl4, PdCl2 and Pd(OAc)2, preferably KPdCl4; (3) The molar ratio of the palladium source to the silicon source is 0.004 - 0.02:1, preferably 0.01:1; (4) The concentration of the silicon source in the ethanol solution is 1 - 5 g / mL, preferably 2 g / mL; (5) The volume ratio of the acetic acid to the ethanol is 1:10; (6) The adjusting of the pH is to adjust the pH to 7 - 8; (7) The reducing agent is sodium triacetoxyborohydride; (8) The organic solvent is tetrahydrofuran; (9) The molar ratio of Pd in the Pd / SiO2 to the reducing agent is 1:
6.
9. A preparation method of gel-loaded Pd / SiO2, characterized in that, It includes the following steps: An ethanol solution of a silicon source is mixed with acetic acid and heated to remove ethanol. The resulting alcohol-free sol is mixed with an aqueous and acetonitrile solution of a palladium source, the pH is adjusted, and after ultrasonic dispersion and drying, in an organic solvent, under an inert gas condition, it is reduced by a reducing agent to obtain a Pd / SiO2 catalyst.
10. The preparation method according to claim 9, characterized in that, The reaction conditions of the preparation method are as described in claim 8.