Preparation method of squalane

Abstract

The invention provides a preparation method of squalane, and belongs to the technical field of chemical production. The preparation method of squalane comprises the following steps: 1) mixing squalene and isopropanol, adding a catalyst, introducing hydrogen, and carrying out hydrogenation reaction to obtain a mixed reaction product containing squalane; 2, the mixed reaction product containing squalane is subjected to molecular distillation, and squalane and acetone are obtained.According to the method, a squalene hydrogenation reaction and an isopropanol dehydrogenation reaction are conducted at the same time, high-quality squalane and acetone are continuously produced, the danger of temperature runaway is avoided, meanwhile, the service life of a catalyst is prolonged, and industrial production is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical production, and in particular relates to a method for preparing squalane. Background Art

[0002] Squalene is also known as 30 carbon hexaene, with a chemical formula of C 30 H 50 , is a type of long-chain olefin containing six double bonds, and is an acyclic triterpene composed of 6 isoprenes. Squalene exists in the human body's sebum membrane and can participate in the biosynthesis and metabolic reactions of cholesterol. It is commonly found in a variety of foods, among which shark liver oil has a high content, and a few plants such as olive oil and rice bran oil also have relatively high content. Squalene is unstable and easily oxidized to produce a special odor, but its fully hydrogenated product squalane shows extremely high application value in cosmetics. Squalane is colorless, odorless, non-toxic, has high chemical stability, has good affinity for the skin, does not cause allergies and irritation, has a moisturizing effect, and can repair the skin barrier, resist aging and oxidation, promote metabolism, and have antibacterial and antibacterial effects.

[0003] At present, the use of squalene hydrogenation in a reactor to prepare squalane has a long production cycle, and the long-term high temperature makes unstable double bonds easily generate by-products and by-products such as cyclosqualane. In addition, the above-mentioned kettle hydrogenation process has the disadvantages of low reaction efficiency, the catalyst cannot be reused, and the product needs to be separated and decolorized. Patent CN112745186A adopts a two-step hydrogenation process to hydrogenate squalene in stages, and obtains a higher yield. However, the operation is relatively complicated and the process is cumbersome. The use of squalene hydrogenation in a fixed bed to prepare squalane hydrogenation has a large and rapid heat release, which is easy to cause the danger of temperature rise and threaten the stability of the catalyst. Summary of the invention

[0004] In view of this, the present invention provides a method for preparing squalane. In the method provided by the present invention, squalene hydrogenation reaction and isopropanol dehydrogenation reaction are carried out simultaneously, so as to realize continuous production of high-quality squalane and acetone, avoid the risk of temperature runaway and increase the service life of the catalyst, which is conducive to industrial production.

[0005] In order to achieve the above object, the present invention provides a method for preparing squalane, comprising the following steps: 1) mixing squalene and isopropanol, adding a catalyst and introducing hydrogen to carry out a hydrogenation reaction to obtain a mixed reaction product containing squalane; 2) molecularly distilling the mixed reaction product containing squalane to obtain squalane and acetone; In step 1), the catalyst is a mixture of a nickel-based catalyst and a copper-based catalyst; the mass ratio of the nickel-based catalyst to the copper-based catalyst is 6-10:6-11; the temperature during the hydrogenation reaction is 110-240° C. and the pressure is 0.5-5.0 MPa.

[0006] Preferably, the squalene in step 1) is produced by microorganisms.

[0007] Preferably, the amount of squalene used in step 1) is more than 30% of the total mass of squalene and isopropanol.

[0008] Preferably, the nickel content in the nickel-based catalyst is 30-80wt%; the copper content in the copper-based catalyst is 10-80wt%.

[0009] Preferably, the hydrogenation reaction in step 1) is carried out in a fixed bed.

[0010] Preferably, in step 1), the flow rate of hydrogen is 100-500 mL / min, and the injection rate of the mixture of squalene and isopropanol is 0.1-1.5 mL / min.

[0011] Preferably, the temperature during the molecular distillation in step 2) is 80-160° C. and the pressure is 10-300 Pa.

[0012] Compared with the prior art, the advantages and positive effects of the present invention are: The present invention uses squalene and isopropanol as a composition, utilizes squalene hydrogenation to release heat, and isopropanol dehydrogenation to absorb heat, and the two reactions are carried out simultaneously and synergistically, thereby avoiding heat waste and the risk of temperature runaway, and can also increase the service life of the catalyst. At the same time, a fixed bed hydrogenation process is adopted to achieve continuous and stable production, and obtain high-quality, low-cost products. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the gas phase spectrum of squalane prepared in Example 1. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] The present invention provides a method for preparing squalane, comprising the following steps: 1) mixing squalene and isopropanol, adding a catalyst and introducing hydrogen to carry out a hydrogenation reaction to obtain a mixed reaction product containing squalane; 2) The mixed reaction product containing squalane is molecularly distilled to separate squalane and acetone.

[0016] The present invention mixes squalene and isopropanol, adds a catalyst and passes hydrogen to carry out a hydrogenation reaction to obtain a mixed reaction product containing squalane. In the present invention, the above-mentioned squalene is preferably produced by microorganisms. In the present invention, squalene is produced by microorganisms, and its purity is ≥98%, it is safer, has good skin-friendly properties, and there is no harm to the human body caused by residual heavy metals. The present invention does not specifically limit the specific source of the microbial squalene, and conventional commercial products in this field can be used. The squalene used in the embodiment of the present invention is purchased from Senruis Biotechnology (Shenzhen) Co., Ltd. In the present invention, the amount of squalene is preferably more than 30% of the total mass of squalene and isopropanol, and more preferably 40% to 60%. In the present invention, the catalyst is a mixture of a nickel-based catalyst and a copper-based catalyst. The mass ratio of the nickel-based catalyst to the copper-based catalyst is preferably 6 to 10:6 to 11. In the present invention, the nickel-based catalyst is used for the hydrogenation reaction of squalene, and the copper-based catalyst is used for the dehydrogenation reaction of isopropanol. In the present invention, the nickel-based catalyst is preferably supported by silicon oxide, activated carbon or aluminum oxide, and nickel is loaded. In the present invention, the content of nickel in the nickel-based catalyst is preferably 30-80wt%. In the present invention, the content of copper in the copper-based catalyst is preferably 10-80wt%.

[0017] In the present invention, the structural formula of squalene is as shown in Formula I:

[0018] In the present invention, the reaction formula for the hydrogenation reaction of squalene is shown as (1): (1) In the present invention, the equation for the isopropanol dehydrogenation reaction is shown in (2): (2) In the present invention, the hydrogenation reaction is preferably carried out in a fixed bed. The present invention does not specifically limit the specific structure of the fixed bed, and a conventional fixed bed in the art can be used. In the present invention, the temperature during the hydrogenation reaction is 110~240°C, preferably 120~150°C; the pressure during the hydrogenation reaction is preferably 0.5~5.0MPa, more preferably 1.5~3.0MPa. During the hydrogenation reaction, the temperature is insufficient and there are incomplete hydrogenation products in the product, but too high a temperature will aggravate the occurrence of side reactions such as cracking reactions, and the impurities of the product will increase. It can be understood that the temperature defined in the present invention is the optimal reaction temperature range. In the present invention, when the hydrogenation reaction is carried out, it is preferably heated to the reaction temperature at a heating rate of 2~5°C / min, but based on the hydrogenation of squalene, a large amount of heat will be generated instantly, so after reaching a certain temperature to initiate the hydrogenation reaction, there will be an instantaneous heating process. At the same time, based on the isopropanol dehydrogenation reaction, heat absorption will be carried out, so that the instantaneous temperature rise can be made lower, thereby avoiding the occurrence of the temperature rise phenomenon. In the present invention, when the hydrogenation reaction is carried out in a fixed bed, the flow rate of hydrogen is preferably 100-500 mL / min, more preferably 180-300 mL / min; the injection rate of the squalene and isopropanol mixture is preferably 0.1-1.5 mL / min, more preferably 0.3-0.8 mL / min.

[0019] After obtaining the mixed reaction product containing squalane, the present invention performs molecular distillation on the mixed reaction product containing squalane to obtain squalane and acetone. In the present invention, the temperature during the molecular distillation is preferably 80-160° C., and the pressure is preferably 10-300 Pa.

[0020] The method for preparing acetone by catalytic dehydrogenation of isopropanol currently has the following characteristics: the reaction is a strong endothermic reaction, and the heat absorbed by alcohol dehydrogenation is 60.8KJ / mol. During the reaction, in order to keep the temperature of the reaction bed under suitable conditions, it is necessary to continuously input heat into the reaction bed, otherwise the temperature of the reaction bed is uneven, which affects the uniform and effective performance of the catalyst activity, thereby affecting the service life of the catalyst and the stable operation of the production device. The present invention uses squalene and isopropanol as a composition, utilizes squalene hydrogenation to release heat, and isopropanol dehydrogenation absorbs heat. The two reactions are carried out simultaneously to avoid heat waste and the risk of temperature rise, and at the same time, there is no obvious temperature rise accumulation point on the surface of the hydrogenation catalyst, which reduces the harm to the catalyst, thereby increasing the service life of the catalyst. At the same time, a fixed bed hydrogenation process is adopted to achieve continuous and stable production and obtain high-quality, low-cost products.

[0021] The present invention provides squalane prepared by any one of the preparation methods described above, wherein the squalane has an iodine value of ≤3.0 g / 100 g and an acid value of ≤0.05 mg KOH / g.

[0022] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0023] Note: Although the catalysts in some examples of this application are the same catalyst from the same manufacturer, the nickel / copper content in the catalysts may vary due to different production batches. The specific content is noted in each example.

[0024] Example 1 The composition of squalene and isopropanol produced by microorganisms was used as raw material (squalene in the raw material accounted for 43.2% of the total weight of the composition). 50 g of nickel-based catalyst and 50 g of copper-based catalyst were added to the fixed bed reactor (the nickel-based catalyst was silicon oxide-supported nickel, specifically Ni-8046 (four-leaf clover type) produced by Shanghai Xunkai, with a nickel content of 55%; the copper-based catalyst was Cu-8112 produced by Shanghai Xunkai, with a copper content of 50%). The hydrogenation reaction was carried out by heating the temperature from room temperature at a heating rate of 2°C / min. However, since squalene hydrogenation rapidly releases heat, the temperature instantly rises to 110°C after the hydrogenation is initiated at a certain temperature. Then, based on the exothermic dehydrogenation reaction of isopropanol, the temperature rises to 110°C and then stabilizes. Then, the temperature is steadily raised to 130°C at a rate of 2°C / min. The hydrogenation temperature was controlled to be 130°C, the hydrogenation pressure was 2.5 MPa, the raw material injection rate was 0.3 mL / min, the hydrogen flow rate was 200 mL / min, and the reaction was continued to obtain a mixed reaction product containing squalane.

[0025] The mixed reaction product containing squalane was molecularly distilled (the temperature of molecular distillation was controlled to be 80°C and the pressure was 120Pa). The light component obtained after molecular distillation was acetone, and the heavy component was squalane. The heavy component was detected by gas phase detection. The gas phase spectrum is as follows Figure 1 The yield of squalane obtained is 96.3%, the purity is 99.2%, the iodine value of the product is 1.46 g / 100g, the saponification value is 1.38 mg KOH / g, the acid value is 0.02 mg KOH / g, and the product is colorless and odorless.

[0026] After 36 hours of operation, the reaction was stopped and the catalyst was subjected to thermogravimetric analysis. The catalyst had no obvious weight loss at 300-500°C and no exothermic peak, indicating that no carbon deposition was generated. This indicates that the catalyst had no obvious changes after 36 hours of reaction and had a long service life.

[0027] Example 2 The composition of squalene and isopropanol produced by microorganisms was used as raw material (squalene in the raw material accounted for 60% of the total weight of the composition). 30 g of nickel-based catalyst and 40 g of copper-based catalyst were added to the fixed bed reactor (the nickel-based catalyst was nickel supported on activated carbon, specifically Ni-8046 (four-leaf clover type) produced by Shanghai Xunkai, with a nickel content of 55%; the copper-based catalyst was Cu-8112 produced by Shanghai Xunkai, with a copper content of 50%). The hydrogenation reaction was carried out by heating the temperature from room temperature at a heating rate of 2°C / min. However, since squalene hydrogenation rapidly releases heat, the temperature instantly rises to 110°C after the hydrogenation is initiated at a certain temperature. Then, based on the exothermic dehydrogenation reaction of isopropanol, the temperature rises to 110°C and then stabilizes. Then, the temperature is steadily raised to 130°C at a rate of 2°C / min. The hydrogenation temperature was controlled to be 130°C, the hydrogenation pressure was 2.5 MPa, the raw material injection rate was 0.3 mL / min, the hydrogen flow rate was 200 mL / min, and the reaction was continued to obtain a mixed reaction product containing squalane.

[0028] The mixed reaction product containing squalane was molecularly distilled (the temperature of the molecular distillation was controlled at 95°C and the pressure was 60Pa). The light component obtained after the molecular distillation was acetone, and the heavy component was squalane. The yield of squalane was 96.8%, the purity of squalane was 98.4%, and it was colorless and odorless. The measured iodine value of the product was 2.73 g / 100g, the saponification value was 1.47 mg KOH / g, and the acid value was 0.05 mg KOH / g.

[0029] After 36 hours of operation, the reaction was stopped and the catalyst was subjected to thermogravimetric analysis. The catalyst had no obvious weight loss at 300-500°C and no exothermic peak, indicating that no carbon deposition was generated. This indicates that the catalyst had no obvious changes after 36 hours of reaction and had a long service life.

[0030] Example 3 The composition of squalene and isopropanol produced by microorganisms was used as raw material (squalene in the raw material accounted for 45% of the total weight of the composition). 30 g of nickel-based catalyst and 45 g of copper-based catalyst were added to the fixed bed reactor (the nickel-based catalyst was silicon oxide-supported nickel, specifically Ni-8036 produced by Shanghai Xunkai, with a nickel content of 60%; the copper-based catalyst was Cu-8112 produced by Shanghai Xunkai, with a copper content of 50%). The hydrogenation reaction was carried out by heating the temperature from room temperature at a heating rate of 5°C / min. However, since squalene hydrogenation rapidly releases heat, the temperature instantly rose to 110°C after the hydrogenation was initiated at a certain temperature. Then, based on the exothermic dehydrogenation reaction of isopropanol, the temperature was raised to 110°C and then stabilized. Then, the temperature was steadily raised to 130°C at a rate of 5°C / min. The hydrogenation temperature was controlled to be 130°C, the hydrogenation pressure was 2.5 MPa, the raw material injection rate was 0.3 mL / min, the hydrogen flow rate was 200 mL / min, and the reaction was continued to obtain a mixed reaction product containing squalane.

[0031] The mixed reaction product containing squalane was molecularly distilled (the molecular distillation temperature was controlled at 110°C and the pressure was 50Pa). The light component obtained after molecular distillation was acetone, and the heavy component was squalane. The yield of squalane was 97.1%, the purity of squalane was 98.9%, and it was colorless and odorless. The measured iodine value of the product was 1.82 g / 100g, the saponification value was 1.48 mg KOH / g, and the acid value was 0.04 mg KOH / g.

[0032] After 36 hours of operation, the reaction was stopped and the catalyst was subjected to thermogravimetric analysis. The catalyst had no obvious weight loss at 300-500°C and no exothermic peak, indicating that no carbon deposition was generated. This indicates that the catalyst had no obvious changes after 36 hours of reaction and had a long service life.

[0033] Example 4 The composition of squalene and isopropanol produced by microorganisms was used as raw material (squalene in the raw material accounted for 68% of the total weight of the composition). 30 g of nickel-based catalyst and 30 g of copper-based catalyst were added to the fixed bed reactor (the nickel-based catalyst was silicon oxide-supported nickel, specifically Ni-8046 (four-leaf clover type) produced by Shanghai Xunkai, with a nickel content of 55%; the copper-based catalyst was Cu-8112 produced by Shanghai Xunkai, with a copper content of 80%). The hydrogenation reaction was carried out by heating the temperature from room temperature at a heating rate of 2°C / min. However, since squalene hydrogenation will rapidly release heat, the temperature instantly rose to 141°C after the hydrogenation was initiated at a certain temperature. Then, based on the exothermic dehydrogenation reaction of isopropanol, the temperature was raised to 141°C and then stabilized. Then, the temperature was steadily raised to 150°C at a rate of 2°C / min. The hydrogenation temperature was controlled to be 150°C, the hydrogenation pressure was 2.5 MPa, the raw material injection rate was 0.4 mL / min, the hydrogen flow rate was 200 mL / min, and the reaction was continued to obtain a mixed reaction product containing squalane.

[0034] The mixed reaction product containing squalane was molecularly distilled (the temperature of the molecular distillation was controlled to be 150°C and the pressure was 200Pa). The light component obtained after molecular distillation was acetone, and the heavy component was squalane. The yield of squalane obtained was 95.5%, the purity was 98.6%, and it was colorless and odorless. The measured iodine value of the product was 2.36 g / 100g, the saponification value was 1.29 mg KOH / g, the acid value was 0.05 mg KOH / g, and the light component was acetone.

[0035] After 36 hours of operation, the reaction was stopped and the catalyst was subjected to thermogravimetric analysis. The catalyst had no obvious weight loss at 300-500°C and no exothermic peak, indicating that no carbon deposition was generated. This indicates that the catalyst had no obvious changes after 36 hours of reaction and had a long service life.

[0036] Example 5 The composition of squalene and isopropanol produced by microorganisms was used as raw material (squalene in the raw material accounted for 32% of the total weight of the composition). 30 g of nickel-based catalyst and 55 g of copper-based catalyst were added to the fixed bed reactor (the nickel-based catalyst was silicon oxide-supported nickel, specifically Ni-8046 (four-leaf clover type) produced by Shanghai Xunkai, with a nickel content of 69%; the copper-based catalyst was Cu-8112 produced by Shanghai Xunkai, with a copper content of 50%). The hydrogenation reaction was carried out by heating the temperature from room temperature at a heating rate of 2°C / min. However, since squalene hydrogenation will rapidly release heat, the temperature rises to 123°C instantly after the hydrogenation is initiated at a certain temperature. Then, based on the exothermic dehydrogenation reaction of isopropanol, the temperature rises to 123°C and then stabilizes. Then, the temperature is steadily raised to 130°C at a rate of 2°C / min. The hydrogenation temperature is controlled to be 130°C, the hydrogenation pressure is 2.5 MPa, the raw material injection rate is 0.45 mL / min, the hydrogen flow rate is 300 mL / min, and the reaction is continued to obtain a mixed reaction product containing squalane.

[0037] The mixed reaction product containing squalane was molecularly distilled (the temperature of the molecular distillation was controlled at 90°C and the pressure was 280Pa). The light component obtained after molecular distillation was acetone, and the heavy component was squalane. The yield of squalane obtained was 95.4%, the purity was 98.1%, and it was colorless and odorless. The measured iodine value of the product was 2.92 g / 100g, the saponification value was 1.63 mg KOH / g, the acid value was 0.05 mg KOH / g, and the light component was acetone.

[0038] After 36 hours of operation, the reaction was stopped and the catalyst was subjected to thermogravimetric analysis. The catalyst had no obvious weight loss at 300-500°C and no exothermic peak, indicating that no carbon deposition was generated. This indicates that the catalyst had no obvious changes after 36 hours of reaction and had a long service life.

[0039] Example 6 The composition of squalene and isopropanol produced by microorganisms was used as raw material (squalene in the raw material accounted for 30% of the total weight of the composition). 30 g of nickel-based catalyst and 55 g of copper-based catalyst were added to the fixed bed reactor (the nickel-based catalyst was silicon oxide-supported nickel, specifically Ni-8046 (four-leaf clover type) produced by Shanghai Xunkai, with a nickel content of 62%; the copper-based catalyst was Cu-8112 produced by Shanghai Xunkai, with a copper content of 50%). The hydrogenation reaction was carried out by heating the temperature from room temperature at a heating rate of 3°C / min. However, since squalene hydrogenation rapidly releases heat, the temperature instantly rose to 110°C after the hydrogenation was initiated at a certain temperature. Then, based on the exothermic dehydrogenation reaction of isopropanol, the temperature was raised to 110°C and then stabilized. Then, the temperature was steadily raised to 150°C at a rate of 3°C / min. The hydrogenation temperature was controlled to be 150°C, the hydrogenation pressure was 2.0 MPa, the raw material injection rate was 0.3 mL / min, the hydrogen flow rate was 200 mL / min, and the reaction was continued to obtain a mixed reaction product containing squalane.

[0040] The mixed reaction product containing squalane was molecularly distilled (the temperature of the molecular distillation was controlled to be 140°C and the pressure was 20Pa). The light component obtained after the molecular distillation was acetone, and the heavy component was squalane. The yield of the obtained squalane was 96.9%, the purity was 98.5%, and it was colorless and odorless. The measured iodine value of the product was 2.33 g / 100g, the saponification value was 1.34 mg KOH / g, and the acid value was 0.04 mg KOH / g.

[0041] After 36 hours of operation, the reaction was stopped and the catalyst was subjected to thermogravimetric analysis. The catalyst had no obvious weight loss at 300-500°C and no exothermic peak, indicating that no carbon deposition was generated. This indicates that the catalyst had no obvious changes after 36 hours of reaction and had a long service life.

[0042] Example 7 The composition of squalene and isopropanol produced by microorganisms was used as raw material (squalene accounted for 30% of the total weight of the composition in the raw material). 30 g of nickel-based catalyst and 55 g of copper-based catalyst were added to the fixed bed reactor (the nickel-based catalyst was silicon oxide-supported nickel, specifically Ni-8046 (four-leaf clover type) produced by Shanghai Xunkai, with a nickel content of 40%; the copper-based catalyst was Cu-8112 produced by Shanghai Xunkai, with a copper content of 20%). The hydrogenation reaction was carried out at a heating rate of 3°C / min from room temperature, but squalene hydrogenation rapidly releases heat, so after hydrogenation was initiated at a certain temperature, the temperature rose to 125°C instantly, and then based on the exothermic reaction of dehydrogenation of isopropanol, the temperature rose to 110°C, and then the temperature tended to be stable. The hydrogenation temperature was controlled to be 110°C, the hydrogenation pressure was 5.0 MPa, the raw material injection rate was 1.5 mL / min, and the hydrogen flow rate was 500 mL / min. The reaction was continued to obtain a mixed reaction product containing squalane.

[0043] The mixed reaction product containing squalane was molecularly distilled (the temperature of the molecular distillation was controlled to be 150°C and the pressure was 10Pa). The light component obtained after the molecular distillation was acetone, and the heavy component was squalane. The yield of squalane obtained was 93.4%, the purity was 99.1%, the iodine value of the product was 1.12 g / 100g, the saponification value was 0.89mg KOH / g, the acid value was 0.02mgKOH / g, and the product was colorless and odorless.

[0044] After 36 hours of operation, the reaction was stopped and the catalyst was subjected to thermogravimetric analysis. The catalyst had no obvious weight loss at 300-500°C and no exothermic peak, indicating that no carbon deposition was generated. This indicates that the catalyst had no obvious changes after 36 hours of reaction and had a long service life.

[0045] Example 8 The composition of squalene and isopropanol produced by microorganisms was used as raw material (squalene in the raw material accounted for 43.2% of the total weight of the composition). 50 g of nickel-based catalyst and 40 g of copper-based catalyst were added to the fixed bed reactor (the nickel-based catalyst was silicon oxide-supported nickel, specifically Ni-8046 (four-leaf clover type) produced by Shanghai Xunkai, with a nickel content of 55%; the copper-based catalyst was Cu-8112 produced by Shanghai Xunkai, with a copper content of 70%). The hydrogenation reaction was carried out by heating the temperature from room temperature at a heating rate of 3°C / min. However, since squalene hydrogenation rapidly releases heat, the temperature instantly rose to 125°C after the hydrogenation was initiated at a certain temperature. Then, based on the exothermic dehydrogenation reaction of isopropanol, the temperature was raised to 125°C and then stabilized. Then, the temperature was steadily raised to 240°C at a rate of 3°C / min. The hydrogenation temperature was controlled to be 240°C, the hydrogenation pressure was 0.5 MPa, the raw material injection rate was 0.1 mL / min, the hydrogen flow rate was 100 mL / min, and the reaction was continued to obtain a mixed reaction product containing squalane.

[0046] The mixed reaction product containing squalane was molecularly distilled (the temperature of the molecular distillation was controlled to be 80°C and the pressure was 300Pa). The light component obtained after the molecular distillation was acetone, and the heavy component was squalane. The yield of squalane obtained was 99.2%, the purity was 98.12%, the iodine value of the product was 2.45 g / 100g, the saponification value was 1.38mg KOH / g, the acid value was 0.05mgKOH / g, and the product was colorless and odorless.

[0047] After 36 hours of operation, the reaction was stopped and the catalyst was subjected to thermogravimetric analysis. The catalyst had no obvious weight loss at 300-500°C and no exothermic peak, indicating that no carbon deposition was generated. This indicates that the catalyst had no obvious changes after 36 hours of reaction and had a long service life.

[0048] Comparative Example 1 The composition of squalene and isopropanol produced by microorganisms was used as raw material (squalene in the raw material accounted for 43.2% of the total weight of the composition). 50 g of nickel-based catalyst (the nickel-based catalyst was silicon oxide-supported nickel, specifically Ni-8046 produced by Shanghai Xunkai, with a nickel content of 55%) was added to the fixed bed reactor. The hydrogenation reaction was carried out at a heating rate of 2°C / min from room temperature. However, since squalene hydrogenation will rapidly release heat, the temperature rises to 198°C instantly after hydrogenation is initiated at a certain temperature, and then cools to 130°C. The hydrogenation temperature is controlled to be 130°C, the hydrogenation pressure is 2.5 MPa, the raw material injection rate is 0.3 mL / min, and the hydrogen flow rate is 200 mL / min. The reaction is continued to obtain a mixed reaction product containing squalane.

[0049] The mixed reaction product containing squalane was molecularly distilled (the temperature of the molecular distillation was controlled at 80°C and the pressure was 120Pa). The yield of squalane obtained was 94.3%, the purity of the squalane obtained was 96.5%, and it was colorless and odorless. The measured iodine value of the product was 3.12 g / 100g, the saponification value was 1.25 mg KOH / g, and the acid value was 0.08 mg KOH / g.

[0050] After running for 36 hours, the reaction was stopped and the catalyst was characterized and analyzed. Thermogravimetric analysis showed that the weight of the catalyst decreased by 2% between 300-500°C and there was an exothermic signal peak, indicating that carbon deposition occurred, which affected the catalytic life. Comparison of Example 1 and Comparative Example 1 showed that after the hydrogenation reaction was initiated, the temperature of Comparative Example 1 increased significantly instantly, resulting in a temperature runaway phenomenon, which affected the stability of the catalyst.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing squalane, characterized in that: The steps include: 1) mixing squalene and isopropanol, adding a catalyst and introducing hydrogen to carry out a hydrogenation reaction to obtain a mixed reaction product containing squalane; 2) molecularly distilling the mixed reaction product containing squalane to obtain squalane and acetone; In step 1), the catalyst is a mixture of a nickel-based catalyst and a copper-based catalyst; the mass ratio of the nickel-based catalyst to the copper-based catalyst is 6-10:6-11; the temperature during the hydrogenation reaction is 110-240° C. and the pressure is 0.5-5.0 MPa.

2. The preparation method according to claim 1, characterized in that: The squalene in step 1) is produced by microorganisms.

3. The preparation method according to claim 1, characterized in that: In step 1), the amount of squalene used is more than 30% of the total mass of squalene and isopropanol.

4. The preparation method according to claim 1, characterized in that: The nickel content in the nickel-based catalyst is 30-80wt%; the copper content in the copper-based catalyst is 10-80wt%.

5. The preparation method according to claim 1, characterized in that: In step 1), the hydrogenation reaction is carried out in a fixed bed.

6. The preparation method according to claim 5, characterized in that: In step 1), the flow rate of hydrogen is 100-500 mL / min, and the injection rate of the mixture of squalene and isopropanol is 0.1-1.5 mL / min.

7. The preparation method according to claim 1, characterized in that: The temperature during the molecular distillation in step 2) is 80-160°C and the pressure is 10-300Pa.

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