Method for extracting and refining vegetable wax from lignin sterol by-product

Abstract

The invention discloses a method for extracting and refining vegetable wax from a wood sterol by-product, which comprises the following steps: S1, mixing the wood sterol by-product with a first solvent at a first temperature to obtain a mixed solution; s2, performing crystallization treatment on the mixed solution to obtain a treated mixed solution; s3, filtering the treated mixed solution to obtain recovered cerate and filtrate; s4, recovering the cerate and the first solvent in the filtrate to obtain crude wax; and S5, purifying the crude wax by adopting a column chromatography method to obtain refined wax. The method provided by the invention realizes high-value utilization of waste resources, has the characteristics of large treatment capacity, simple process, low toxicity, environmental protection, low cost and the like, and is suitable for industrial production.

Description

Technical Field

[0001] The present application relates to the field of chemical separation technology, and in particular to a method for extracting and refining plant wax from lignin sterol byproducts. Background Art

[0002] Plant wax has a wide range of uses and is an important industrial resource. It can be used to produce polishes, protective agents, and emulsifiers for fiber manufacturing. Refined plant wax can not only be used as a food additive and a preservative for edible fruits and vegetables, but can also be used in the pharmaceutical field. In addition, plant wax is a renewable energy source, most of which also contains a variety of essential fatty acids for the human body. It is a green, environmentally friendly and healthy natural resource. With the improvement of people's living standards and the increasing attention to environmental protection, the call for strengthening the use of new renewable energy such as plant wax has become stronger.

[0003] Plant wax can be extracted from the production process of plant sterols. For lignans, the raw material of pinewood oil paste can effectively separate and remove fatty acids and other substances through molecular distillation process, and at the same time, it can convert the bound sterols into free sterols, extract more than 98% of lignans, and produce plant wax as a byproduct. Although the existing high-efficiency separation and purification technology can effectively improve the extraction rate and purity of lignans, the complex and variable composition of pinewood oil paste raw materials will increase the difficulty of separating the byproduct plant wax from impurities and the low level of comprehensive utilization of byproducts.

[0004] The solvent crystallization method utilizes the difference in the solubility of the components in the plant wax in the solvent as it changes with temperature, and adopts the method of cooling crystallization to obtain high-purity plant wax. It has little environmental pollution and is easy to obtain high-purity products. It can also be separated and purified in a targeted manner according to the change pattern of the solubility of different components with temperature, which can greatly improve the purity of the solid components in the system and has good industrial application prospects.

[0005] However, the vegetable wax produced by the solvent crystallization method is generally called crude wax. For example, crude bran wax contains not only wax esters, but also hydrocarbons, acylglycerols, free fatty acids, free alcohols and colloidal impurities. The presence of these substances will not only affect the application of the wax, but also cause a large amount of waste of neutral oils. At the same time, some pigments and other substances in the crude wax will make the wax darker in color. Therefore, a refining process is required to obtain high-quality vegetable wax.

[0006] As for the refining methods of plant wax, the most reported methods include solvent extraction separation, physical adsorbent adsorption, strong oxidant oxidation, and column chromatography. However, the solvent extraction separation method requires a large amount of solvent and high equipment investment; the physical adsorbent adsorption method has low adsorption efficiency and insignificant decolorization effect; although the strong oxidant oxidation method has obvious decolorization effect, the oxidation stability and storage stability of the wax are very low. Compared with other separation methods, column chromatography has the advantages of low energy consumption, easy recycling of eluents, and high purity of the obtained products, but the improvement of color and other physical and chemical indicators needs to be optimized and improved. Summary of the invention

[0007] In view of the above problems in the prior art, the present application provides a method for extracting and refining plant wax from lignansterol by-products.

[0008] In a first aspect, the present application provides a method for extracting refined plant wax from lignin sterol byproducts, comprising the following steps:

[0009] S1: mixing the lignin sterol byproduct and the solvent at a first temperature to obtain a mixed solution;

[0010] S2: performing a crystallization treatment or an extraction treatment on the mixed solution to obtain a treated mixed solution;

[0011] S3: filtering the treated mixed liquid to obtain recovered wax paste and filtrate;

[0012] S4: recovering the first solvent in the wax paste and the filtrate to obtain crude wax;

[0013] S5: Purifying the crude wax by column chromatography to obtain refined wax.

[0014] In some embodiments, the first solvent is selected from one or more of ketone solvents, amide solvents, alcohol solvents and ester solvents.

[0015] The solvent crystallization method uses the difference in the solubility of the components in the plant wax in the solvent with temperature to obtain high-purity plant wax by cooling and crystallizing. It has little environmental pollution and is easy to obtain high-purity products. It can also be separated and purified in a targeted manner according to the change of the solubility of different components with temperature, which can greatly improve the purity of the solid components in the system. The solvent extraction method is a method of separation based on the principle of different solubility of wax and oil in solvent. This method is simple to operate, has no wastewater discharge, has good finished product quality, and the neutral oil can be recycled. It is currently the most commonly used method for the preparation of plant wax, and the yield is relatively high.

[0016] The inventors of the present application have found through extensive research that the solvent crystallization method has a high conversion rate and yield for extracting plant wax from lignin sterol byproducts (lignin sterol molecular distillation waste), and the product purity is high, so it is possible to effectively extract plant wax from lignin sterol molecular distillation waste and is suitable for industrial production and application. At the same time, the crude wax of the solvent crystallization method is purified and refined by column chromatography, which can improve the purity and color of the product and further expand its scope of application.

[0017] In some embodiments, in step S5, purifying the crude wax by column chromatography comprises:

[0018] S51: mixing the crude wax with the second solvent to obtain a crude wax mixed liquid;

[0019] S52: passing the crude wax mixture into a chromatography column, adding an eluent for elution, and separating at a second temperature and a second flow rate to obtain a separated eluent;

[0020] S53: removing the solvent from the eluent to obtain refined wax.

[0021] In some embodiments, the adsorbent in the chromatography column is selected from one or more of silica gel, kaolin, activated carbon, resin and activated alumina. In some embodiments, the adsorbent in the chromatography column is silica gel, activated alumina and activated carbon. Considering the dispersibility of the adsorbent in the solvent and the purity and whiteness of the product wax, according to some preferred embodiments of the present invention, the adsorbent filler is one or more of silica gel, activated alumina and activated carbon.

[0022] In some embodiments, in step S51, the mass of crude wax and the volume ratio of the second solvent are 1g:1mL-1g:100mL, for example, 1g:5mL, 1g:10mL, 1g:15mL, 1g:20mL, 1g:25mL, 1g:30mL, 1g:35mL, 1g:40mL, 1g:45mL, 1g:50mL, 1g:55mL, 1g:60mL, 1g:65mL, 1g:70mL, 1g:75mL, 1g:80mL, 1g:85mL, 1g:90mL, 1g:95mL or any value therebetween. In some embodiments, the mass of crude wax and the volume ratio of the second solvent are 1g:2mL-1g:80mL. In some embodiments, the mass of crude wax and the volume ratio of the second solvent are selected as 1g:2.5mL-1g:60mL.

[0023] In some embodiments, in step S51, the second solvent is selected from one or more of ketone solvents, alcohol solvents, ester solvents, halogenated alkane solvents with a carbon number of 1-5, and alkane solvents with a carbon number of 5-12.

[0024] In some embodiments, in step S52, the number of elutions is 3-5 times.

[0025] In some embodiments, in step S52, the eluent is one or more of 5-12 alkane solvents. In some embodiments, in step S52, the eluent is the same as the second solvent.

[0026] In some embodiments, in step S52, the second temperature is 25°C-50°C, for example, 30°C, 35°C, 40°C or 45°C. In some embodiments, the second temperature is 30°C-40°C.

[0027] In some embodiments, in step S52, the second flow rate is 1-5 mL / min, for example, 2 mL / min, 3 mL / min or 4 mL / min.

[0028] In some embodiments, the ketone solvent is selected from one or more of acetone, methyl ethyl ketone and methyl isobutyl ketone.

[0029] In some embodiments, the amide solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and N-propylpyrrolidone.

[0030] In some embodiments, the alcohol solvent is selected from one or more of C1-C6 alcohols. In some embodiments, the alcohol solvent is selected from one or more of methanol, ethanol and n-propanol.

[0031] In some embodiments, the ester solvent is selected from one or more of ethyl acetate, ethyl formate, methyl acetate and n-propyl acetate.

[0032] In some embodiments, the halogenated alkane solvent having a carbon number of 1-5 is selected from one or more of dichloromethane, chloroform and trichloroethane.

[0033] In some embodiments, the alkane solvent having a carbon number of 5-12 is selected from one or more of cyclopentane, n-hexane, cyclohexane, methylcyclohexane, isopentane, n-octane and isooctane.

[0034] In some embodiments, the first solvent is selected from one or more of N,N-dimethylformamide, acetone, ethanol and ethyl acetate.

[0035] In some embodiments, the second solvent is selected from one or more of n-hexane, acetone, dichloromethane, methanol and ethyl acetate, for example, n-hexane, acetone or dichloromethane.

[0036] In some embodiments, the eluent is selected from one or more of n-hexane, acetone, dichloromethane, methanol and ethyl acetate. Considering the properties of the filler and the separation system, according to some preferred embodiments of the present application, the eluent is n-hexane, acetone and dichloromethane.

[0037] In some embodiments, the lignanol by-product is selected from waste generated during the molecular distillation process of producing lignanol.

[0038] In some embodiments, the lignanol by-product is selected from waste generated during the molecular distillation process of producing lignanol from pine oil.

[0039] In some embodiments, the waste includes higher fatty acid compounds, higher fatty alcohol compounds and higher fatty acid and fatty alcohol ester compounds.

[0040] In some embodiments, the ratio of the mass of the lignansterol byproduct to the volume of the solvent (solid-liquid ratio) is 1g:1mL-1g:25mL, for example, 1g:2mL, 1g:2.5mL, 1g:3mL, 1g:3.5mL, 1g:4mL, 1g:4.5mL, 1g:5mL, 1g:5.5mL, 1g:6mL, 1g:6.5mL, 1g:7mL, 1g:7.5mL, 1g:8mL , 1g:8.5mL, 1g:9mL, 1g:9.5mL, 1g:10mL, 1g:11mL, 1g:12mL, 1g:13mL, 1g:14mL, 1g:15mL, 1g:16mL, 1g:17mL, 1g:18mL, 1g:19mL, 1g:20mL, 1g:21mL, 1g:22mL, 1g:23mL, 1g:24mL or any value therebetween. With the increase of the solid-liquid ratio, the extraction rate of the wax decreases but the purity increases significantly. Considering the production cost and environmental protection factors, the solid-liquid ratio is within the above range.

[0041] In some embodiments, the ratio of the mass of the lignansterol byproduct to the volume of the solvent is 1 g:2 mL to 1 g:20 mL. In some embodiments, the ratio of the mass of the lignansterol byproduct to the volume of the solvent is 1 g:2.5 mL to 1 g:10 mL.

[0042] In some embodiments, in step S2, the crystallization treatment comprises: cooling the mixed solution to a third temperature for crystallization under the first stirring condition to obtain a mixed solution after the crystallization treatment.

[0043] In some embodiments, in step S2, the first temperature is 5°C-10°C higher than the precipitation temperature of the plant wax in the lignansterol by-product, for example, 6°C, 7°C, 8°C or 9°C higher. In some embodiments, the first temperature is 30°C-40°C, for example, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C or 39°C.

[0044] In some embodiments, the cooling rate is 1-10.0°C / min, for example, 1.5°C / min, 2°C / min, 2.5°C / min, 3°C / min, 3.5°C / min, 4°C / min, 4.5°C / min, 5°C / min, 5.5°C / min, 6°C / min, 6.5°C / min, 7°C / min, 7.5°C / min, 8°C / min, 8.5°C / min, 9°C / min, 9.5°C / min or any value therebetween. In some embodiments, the cooling rate is 1-5.0°C / min. As the cooling rate increases, the wax extraction first increases and then slowly decreases, and the purity decreases. The cooling rate is preferably within the above range.

[0045] In some embodiments, the third temperature is -20°C to 20°C, for example, -19°C, -18°C, -17°C, -16°C, -15°C, -14°C, -13°C, -12°C, -11°C, -10°C, -9°C, -8°C, -7°C, -6°C, -5°C, -4°C, -3°C, -2°C, -1°C, 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C or any value therebetween. In some embodiments, the third temperature is -10°C to 10°C. In some embodiments, the third temperature is -5°C to 5°C. As the third temperature (final material temperature) increases, the wax extraction rate gradually increases, the purity of the wax slowly decreases, and the final material temperature is preferably within the above range.

[0046] In some embodiments, the speed of the first stirring is 5-150r / min, for example, 10r / min, 20r / min, 30r / min, 40r / min, 50r / min, 60r / min, 70r / min, 80r / min, 90r / min, 100r / min, 110r / min, 120r / min, 130r / min, 140r / min or any value therebetween. In some embodiments, the speed of the first stirring is 10-140r / min. In some embodiments, the speed of the first stirring is 20-50r / min. As the stirring speed increases, wax extraction first increases and then decreases, and the purity of the wax slowly decreases, and the stirring speed is preferably within the above range.

[0047] In some embodiments, the crystallization treatment time is 0.5-24h, for example, 3h, 5h, 7h, 10h, 12h, 15h, 18h, 20h or 22h. In some embodiments, the crystallization treatment time is 5-20h.

[0048] In some embodiments, the solvent in the wax paste and the filtrate is recovered by rotary evaporation and / or heating evaporation.

[0049] In some embodiments, the solvent in the eluent is recovered by rotary evaporation and / or heating evaporation.

[0050] In some embodiments, the method comprises the following specific steps:

[0051] (1) mixing a solvent with a lignin sterol molecular distillation waste raw material liquid to obtain a mixed liquid, wherein the mixing temperature is slightly higher than the wax precipitation temperature of the raw material liquid to obtain a clear solution;

[0052] (2) Rapidly transfer the mixed solution to a heat exchange bottle and place a stoppered stirring wing, cool to -20 to 20°C, and maintain for 0.5 to 24 hours;

[0053] (3) filtering the cooled mixed solution to obtain wax paste and filtrate;

[0054] (4) heating the wax paste to evaporate and recover the solvent to obtain crude wax, weighing the mass of the sample after desolventization and determining the purity;

[0055] (5) heating the filtrate to evaporate and recover the solvent to obtain a dewaxed oil;

[0056] (6) dissolving the crude wax obtained by the solvent crystallization method in a certain amount of solvent;

[0057] (7) mixing the adsorbent and the solvent solution to form a chromatography column by a wet method, passing the mixed solution through the chromatography column, and adding an eluent again for elution, and separating at a certain flow rate under the condition of 25 to 50° C.;

[0058] (8) collecting the eluate after separation, performing rotary evaporation and desolventizing to obtain refined vegetable wax.

[0059] In a second aspect, the present application provides a refined plant wax obtained according to the method described in the first aspect.

[0060] Compared with the prior art, this application has the following advantages:

[0061] (1) The present application utilizes solvent crystallization to extract plant wax from lignin sterol molecular distillation waste with a high extraction rate and yield, and the product purity is also high.

[0062] (2) The solvent crystallization method was optimized and the parameters were adjusted, including the amount of solvent and operating temperature, taking into account the cost and actual working conditions, to make it more promising for industrial application.

[0063] (3) Solve the problem that the wax crystals of the conventional dewaxing solvents in the dewaxing of the extracted oil are small and difficult to filter, and the wax crystals are large and contain little oil.

[0064] (4) Compared with traditional solvent dewaxing, the filtration speed is increased by 30-50% and the dewaxing temperature difference is reduced by 5-10℃.

[0065] (5) The purity of plant wax can be further improved by column chromatography, and the decolorization effect is particularly significant.

[0066] (6) The prepared plant wax has a white micro-bead appearance and has the characteristics of short melting range, low viscosity, high whiteness and good lubrication and dispersibility. It can play the role of lubrication, demolding, brightening, anti-aging and anti-water loss. It has a wider application prospect in the fields of plastics, coatings, inks and rubber, and further enhances the industrial value of the waste of lignin sterol molecular distillation. DETAILED DESCRIPTION

[0067] The present application is further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application, but not to limit the protection scope of the present application.

[0068] In the following examples and comparative examples, the lignansterol molecular distillation waste raw material liquid comes from the waste of lignansterol molecular distillation in the production of pine oil paste, and is mainly composed of higher fatty acid compounds, higher fatty alcohol compounds and higher fatty acid fatty alcohol ester compounds.

[0069] Example 1

[0070] Solvent crystallization method for extracting crude wax

[0071] 100 mL of solvent acetone and 10 g of lignin sterol molecular distillation waste raw material liquid were mixed to obtain a mixed solution, the mixing temperature was 35°C, and a clear solution was obtained by stirring. The mixed solution was quickly transferred to a heat exchange bottle and a plugged stirring wing was placed, and the temperature was cooled to 5°C at a cooling rate of 2°C / min, and maintained at a stirring rate of 20r / min for 12 hours. The cooled mixed solution was quickly filtered while cold to obtain wax paste and filtrate.

[0072] The wax paste was heated and evaporated to recover the solvent to obtain crude wax, and the mass of the sample after desolventization was weighed to be 2.2 g, the yield was 22.0%, and the purity was determined to be 75.0%. The filtrate was heated and evaporated to recover the solvent to obtain dewaxed oil.

[0073] Crude wax refining

[0074] 10g crude wax obtained by solvent crystallization was dissolved in 500mL normal hexane to obtain a crude wax mixture. Silica gel (for thin layer chromatography, 70-230 mesh) and normal hexane were mixed by wet method to prepare a chromatography column (30×300mm), the mixed solution was passed through the chromatography column, the chromatography column was kept at a column temperature of 30°C to ensure that the wax did not precipitate, the crude wax solution was slowly poured in, the effluent was collected at a flow rate of 3mL / min, and the eluent normal hexane was added again for 2-3 times of elution. The separated eluent was collected and desolventized by rotary evaporation at 50°C to obtain 9.2g of refined vegetable wax, the wax color was white, and the purity reached 97.4%.

[0075] Example 2

[0076] Solvent crystallization method for extracting crude wax

[0077] The only difference from Example 1 is that 100 mL of solvent N,N-dimethylformamide is used to replace 100 mL of solvent acetone. The final product yield is 45.2% and the purity is 65.1%.

[0078] Crude wax refining

[0079] The same method as in Example 1 was used to obtain 9.5 g of refined vegetable wax, which was yellowish in color and had a purity of 76.1%.

[0080] Example 3

[0081] Solvent crystallization method for extracting crude wax

[0082] The only difference from Example 1 is that 100 mL of the solvent ethanol is used to replace 100 mL of the solvent acetone. The final product yield is 16.1% and the purity is 70.3%.

[0083] Crude wax refining

[0084] The same method as in Example 1 was used to obtain 8.7 g of refined vegetable wax, which was white in color and had a purity of 82.3%.

[0085] Example 4

[0086] Solvent crystallization method for extracting crude wax

[0087] The only difference from Example 1 is that 100 mL of ethyl acetate is used to replace 100 mL of acetone. The final product yield is 20.3% and the purity is 67.7%.

[0088] Crude wax refining

[0089] The same method as in Example 1 was used to obtain 8.9 g of refined vegetable wax, which was white in color and had a purity of 86.8%.

[0090] Example 5

[0091] Solvent crystallization method for extracting crude wax

[0092] The only difference from Example 1 is that the temperature is lowered to 10° C. at a cooling rate of 2° C. / min. The final product yield is 15% and the purity is 86.2%.

[0093] Crude wax refining

[0094] The same method as in Example 1 was used to obtain 9.3 g of refined vegetable wax, which was white in color and had a purity of 95.3%.

[0095] Example 6

[0096] Solvent crystallization method for extracting crude wax

[0097] The only difference from Example 1 is that the temperature is lowered to 5° C. at a cooling rate of 8° C. / min. The final product yield is 20.9% and the purity is 80.1%.

[0098] Crude wax refining

[0099] The same method as in Example 1 was used to obtain 9.0 g of refined vegetable wax, which was white in color and had a purity of 93.4%.

[0100] Example 7

[0101] Solvent crystallization method for extracting crude wax

[0102] The only difference from Example 1 is that the temperature is lowered to 15° C. at a cooling rate of 10° C. / min. The final product yield is 9.6% and the purity is 84.4%.

[0103] Crude wax refining

[0104] The same method as in Example 1 was used to obtain 8.7 g of refined vegetable wax, which was white in color and had a purity of 95.3%.

[0105] Example 8

[0106] Solvent crystallization method for extracting crude wax

[0107] Same as Example 1.

[0108] Crude wax refining

[0109] Dissolve 10g of crude wax obtained by solvent crystallization in 500mL of n-hexane to obtain a crude wax mixture. Mix activated carbon and n-hexane to make a chromatographic column (30×300mm) by wet method, pass the mixed solution through the chromatographic column, maintain the column temperature of 30°C to ensure that the wax does not precipitate, slowly pour the crude wax solution, collect the effluent at a flow rate of 3mL / min, and add the eluent n-hexane again for 2-3 times of elution. Collect the separated eluent, perform rotary evaporation and desolventization at 50°C, and obtain 9.0g of refined plant wax, the wax color is white, and the purity is 84.0%.

[0110] Example 9

[0111] Solvent crystallization method for extracting crude wax

[0112] Same as Example 1.

[0113] Crude wax refining

[0114] 10g of crude wax obtained by solvent crystallization was dissolved in 500mL of n-hexane to obtain a crude wax mixture. Activated alumina and n-hexane were mixed by wet method to prepare a chromatography column (30×300mm). The mixed solution was passed through the chromatography column, and the column temperature of the chromatography column was maintained at 30°C to ensure that the wax did not precipitate. The crude wax solution was slowly poured in, and the effluent was collected at a flow rate of 3mL / min, and the eluent n-hexane was added again for 2-3 times of elution. The separated eluate was collected and desolventized by rotary evaporation at 50°C to obtain 8.2g of refined vegetable wax, the wax color was off-white, and the purity was 87.8%.

[0115] Example 10

[0116] Solvent crystallization method for extracting crude wax

[0117] Same as Example 1.

[0118] Crude wax refining

[0119] 10g of crude wax obtained by solvent crystallization was dissolved in 500mL of n-hexane to obtain a crude wax mixture. Carclay and n-hexane were mixed by wet method to prepare a chromatography column (30×300mm). The mixed solution was passed through the chromatography column, and the column temperature of the chromatography column was maintained at 30°C to ensure that the wax did not precipitate. The crude wax solution was slowly poured in, and the effluent was collected at a flow rate of 3mL / min, and the eluent n-hexane was added again for 2-3 times of elution. The separated eluate was collected and desolventized by rotary evaporation at 50°C to obtain 8.5g of refined vegetable wax, the wax color was yellowish, and the purity was only 76.2%.

[0120] Embodiment 11

[0121] Solvent crystallization method for extracting crude wax

[0122] Same as Example 1.

[0123] Crude wax refining

[0124] 10g of crude wax obtained by solvent crystallization method was dissolved in 500mL of n-hexane to obtain a crude wax mixture. Macroporous resin and n-hexane were mixed by wet method to prepare a chromatography column (30×300mm). The mixed solution was passed through the chromatography column, and the column temperature of the chromatography column was maintained at 30°C to ensure that the wax did not precipitate. The crude wax solution was slowly poured in, and the effluent was collected at a flow rate of 3mL / min, and the eluent n-hexane was added again for 2-3 times of elution. The separated eluent was collected and desolventized by rotary evaporation at 50°C to obtain 9.3g of refined vegetable wax, which was yellow in color and had a purity of only 75.7%.

[0125] The above embodiments are only used to illustrate the technical solution of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solution of the present application.

Claims

1. A method for extracting and refining vegetable wax from lignansterol byproducts, comprising the following steps: S1: mixing the lignin sterol byproduct and the first solvent at a first temperature to obtain a mixed solution; S2: performing crystallization treatment on the mixed solution to obtain a treated mixed solution; S3: filtering the treated mixed liquid to obtain recovered wax paste and filtrate; S4: recovering the first solvent in the wax paste and the filtrate to obtain crude wax; S5: Purifying the crude wax by column chromatography to obtain refined wax; Preferably, the first solvent is selected from one or more of ketone solvents, amide solvents, alcohol solvents and ester solvents.

2. The method according to claim 1, characterized in that In step S5, purifying the crude wax by column chromatography comprises: S51: mixing the crude wax with the second solvent to obtain a crude wax mixed liquid; S52: passing the crude wax mixture into a chromatography column, adding an eluent for elution, and separating at a second temperature and a second flow rate to obtain a separated eluent; S53: removing the solvent from the eluent to obtain refined wax.

3. The method according to claim 2, characterized in that The adsorbent in the chromatography column is selected from one or more of silica gel, kaolin, activated carbon, resin and activated alumina, preferably one or more of silica gel, activated alumina and activated carbon.

4. The method according to claim 2 or 3, characterized in that: In step S51, the volume ratio of the crude wax to the second solvent is 1g:1mL-1g:100mL, preferably 1g:2mL-1g:80mL, more preferably 1g:2.5mL-1g:60mL; and / or The second solvent is selected from one or more of ketone solvents, alcohol solvents, ester solvents, halogenated alkane solvents with a carbon number of 1-5, and alkane solvents with a carbon number of 5-12.

5. The method according to any one of claims 2 to 4, characterized in that: In step S52, the elution times are 3-5 times; and / or The eluent is selected from one or more of ketone solvents, alcohol solvents, ester solvents, halogenated alkane solvents with a carbon number of 1-5, and alkane solvents with a carbon number of 5-12. Preferably, the eluent is the same as the second solvent; and / or The second temperature is 25°C-50°C, preferably 30°C-40°C; and / or The second flow rate is 1-5 mL / min.

6. The method according to claims 1-5, characterized in that: The ketone solvent is selected from one or more of acetone, methyl ethyl ketone and methyl isobutyl ketone; and / or The amide solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and N-propylpyrrolidone; and / or The alcohol solvent is selected from one or more of C1-C6 alcohols, preferably one or more of methanol, ethanol and n-propanol; The ester solvent is selected from one or more of ethyl acetate, ethyl formate, methyl acetate and n-propyl acetate; and / or The halogenated alkane solvent having a carbon number of 1 to 5 is selected from one or more of dichloromethane, chloroform and trichloroethane; and / or The alkane solvent having a carbon number of 5-12 is selected from one or more of cyclopentane, n-hexane, cyclohexane, methylcyclohexane, isopentane, n-octane and isooctane; Preferably, the first solvent is selected from one or more of N,N-dimethylformamide, acetone, ethanol and ethyl acetate; Preferably, the second solvent is selected from one or more of n-hexane, acetone, dichloromethane, methanol and ethyl acetate, for example, n-hexane, acetone or dichloromethane; Preferably, the eluent is selected from one or more of n-hexane, acetone, dichloromethane, methanol and ethyl acetate, for example, n-hexane, acetone or dichloromethane.

7. The method according to any one of claims 1 to 6, characterized in that The lignanol by-product is selected from waste generated during the molecular distillation process of producing lignanol; Preferably, the lignansterol byproduct is selected from waste generated during the molecular distillation process of pinewood paste to produce lignansterol; Preferably, the waste includes higher fatty acid compounds, higher fatty alcohol compounds and higher fatty acid and fatty alcohol ester compounds.

8. The method according to any one of claims 1 to 7, characterized in that In step S1, the ratio of the mass of the lignansterol byproduct to the volume of the solvent is 1g:1mL-1g:25mL, preferably 1g:2mL-1g:20mL, more preferably 1g:2.5mL-1g:10mL; and / or In step S2, the crystallization treatment includes: cooling the mixed solution to a third temperature for crystallization under the first stirring to obtain a mixed solution after crystallization treatment; Preferably, the first temperature is 5°C-10°C higher than the precipitation temperature of the plant wax in the lignansterol by-product, preferably 30°C-40°C.

9. The method according to claim 8, characterized in that The cooling rate is 1-10.0°C / min, preferably 1-5.0°C / min; and / or The third temperature is -20°C to 20°C, preferably -10°C to 10°C, more preferably -5°C to 5°C; and / or The first stirring rate is 5-150 r / min, preferably 10-140 r / min, more preferably 20-50 r / min; and / or the crystallization treatment time is 0.5-24 h, preferably 5-20 h.

10. A refined vegetable wax obtained according to the method according to any one of claims 1 to 9.