An aromatic active small molecule composition and a method for extracting the same from mulberry wood

Abstract

The application discloses a method for extracting aromatic active small molecule compositions from mulberry wood, in which hemicellulose and other components in the mulberry wood are dissolved by acid, and lignin and cellulose are precipitated; a quaternary ammonium base and an organic acid form an ionic liquid system to selectively dissolve the lignin, and meanwhile, the ionic liquid system breaks the intermolecular connection of the lignin, so that the lignin is cracked into aromatic molecules with different molecular weights. Through the synergistic cooperation of the acid pretreatment and the ionic liquid system, the hemicellulose and the cellulose are separated from the mulberry wood, and the high-activity aromatic small molecules are extracted; meanwhile, the extraction reagent is cheap in source, recyclable, and free of environmental hazards; the extraction process is efficient and energy-saving; and the operation steps are simple and safe.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical and pharmaceutical technology, and particularly relates to an aromatic active small molecule composition and a method for extracting the same from mulberry wood. BACKGROUND

[0002] Mulberry wood is rich in resources, diverse in types, and widely used, especially as a raw material for traditional Chinese medicine, which has attracted much attention. At present, the research on mulberry wood mainly focuses on the extraction of active substances from mulberry wood for chemical production and pharmaceutical field.

[0003] Bio-based active substances are widely available, and have been successfully extracted from mulberry wood. For example, patent CN108578474A reports a mulberry wood liquid extraction process and its application in treating otitis media. The mulberry wood is subjected to cleaning, dehydration, multi-stage fractionation and other processing procedures, and then the extract is subjected to condensation and atomization treatment to successfully extract traditional Chinese medicine ingredients from the mulberry wood. Patent CN113633680A reports a mulberry wood extract preparation method based on ionic liquid and cellulase method. The mulberry wood is subjected to crushing, cellulase treatment and multiple fractionation treatment, and finally the extract is distilled. The method has the advantages of high extraction efficiency, good sterilization effect and improved economic value of mulberry wood. Patent CN109602819A reports a biological preparation preparation method using miscellaneous wood and mulberry wood. Fresh mulberry branches are subjected to crushing, fermentation and distillation to obtain a mulberry extract. The biological reagent is formed by compounding with miscellaneous wood distillation liquid, which has the advantages of nutrient cell repair and low cost.

[0004] Although the above methods can successfully and effectively extract active substances from mulberry wood, there are still some problems. The problems are as follows: (1) fermentation, distillation and other steps are required, the extraction period is long, and the output efficiency needs to be improved; (2) special instruments are required for extraction, increasing the cost of extraction; (3) the purity and yield of the mulberry extract are not clearly characterized, and the utilization efficiency of mulberry substrate is low. SUMMARY

[0005] The purpose of the present application is to provide a method for extracting an aromatic active small molecule composition from mulberry wood. The aromatic small molecule composition extracted by the method has outstanding advantages in yield, purity and activity.

[0006] The present application also provides an aromatic active small molecule composition.

[0007] The technical solution adopted by the present application to solve its technical problems is:

[0008] A method for extracting an aromatic active small molecule composition from mulberry wood, the method comprising the following steps:

[0009] S1, mulberry wood is crushed into powder, and appropriate dilute sulfuric acid is added at room temperature to dissolve and filter to obtain filter residue A; the filter residue A is mixed with the ionic liquid analogue and ultrasonically treated, and then reacted at 100-140 DEG C in an oil bath for 4-8 hours; after the reaction is completed, a good solvent is added to dissolve the reaction product to obtain a mixed solution;

[0010] The amount of the ionic liquid analogue is 20-25 times the weight of the mulberry wood powder.

[0011] The ionic liquid analogue is formed by mixing a quaternary ammonium base component and an organic carboxylic acid component in a molar ratio of 1:1-4; the quaternary ammonium base component is a hydrogen bond acceptor, and is selected from one or more of choline chloride, betaine and tetramethylammonium hydroxide; the organic carboxylic acid component is a hydrogen bond donor, and is selected from one or more of lactic acid, oxalic acid, tartaric acid, malic acid and formic acid.

[0012] S2, the mixed solution obtained in S1 is vacuum filtered to obtain filter liquor B, which is diluted with water to form precipitate C; the precipitate C is washed, centrifuged and dried to obtain an aromatic active small molecule composition.

[0013] Due to the complex chemical structure and material composition of lignocellulose, direct extraction of bio-small molecules from wood will result in poor purity and low activity, and requires benzene-ethanol mixed solvent pretreatment to remove impurities such as pectin, and then extract the lignocellulose component. The pretreatment can improve the purity and activity of the fractionated component, but the pretreatment step mainly using benzene-ethanol is time-consuming, the solvent is difficult to recover, and the cost is high. The dilute sulfuric acid pretreatment has the advantages of simple operation, high hydrolysis efficiency and low cost. In the present application, dilute sulfuric acid is used to hydrolyze pectin, ash and other impurities and hemicellulose in mulberry powder to obtain filter residue containing cellulose and lignin, which is extracted by the ionic liquid analogue formed by quaternary ammonium base and organic carboxylic acid to obtain high-activity aromatic small molecules and separate cellulose. The ionic liquid analogue formed by quaternary ammonium base and organic acid selectively dissolves lignin, and at the same time breaks the intermolecular bonds of lignin to make it crack into aromatic molecules with different molecular weights. Through the synergistic effect of dilute sulfuric acid pretreatment and ionic liquid analogue system, hemicellulose and cellulose are separated from mulberry, and high-activity aromatic active small molecule composition is extracted. The aromatic small molecule has a high content of hydroxyl groups and can be used as an alcohol reaction monomer for the synthesis of polymers, such as the synthesis of phenolic resin, polyurethane elastomer and polyurethane foam products, and shows excellent application prospects.

[0014] Preferably, the mulberry is at least one of Lusang, Huasang, Baizang and Guangdong mulberry, and the raw material is derived from branches, leaves and roots of mulberry tree, and the powder size is 20-120 mesh.

[0015] As preferred, the mass fraction of the dilute sulfuric acid is 1wt%-5wt%, and the optimal mass fraction of the dilute sulfuric acid is 3wt%; the solid-liquid ratio of the mulberry wood powder and the dilute sulfuric acid is 1:20-60, and is further preferably 1:40-50.

[0016] As preferred, the dissolution time of the mulberry wood powder and the dilute sulfuric acid in S1 is 2h-8h, and is more preferably 6h.

[0017] As preferred, the ionic liquid-like solution is formed by mixing choline chloride and organic carboxylic components in a molar ratio of 1:2-4, and the organic carboxylic components are selected from one or more of lactic acid or oxalic acid; and the optimal ionic liquid-like solution is formed by mixing choline chloride and lactic acid in a molar ratio of 1:2.

[0018] As preferred, the good solvent is one or more of methanol, ethanol, ethylene glycol or glycerol, and is preferably ethanol.

[0019] As preferred, when the precipitated C is washed in S2, the washing agent used is an ethanol aqueous solution with a volume fraction of 5%-20%. Further preferably, the ethanol aqueous solution has a volume fraction of 10%-20%, and most preferably, the ethanol aqueous solution has a volume fraction of 10%.

[0020] As preferred, the oil bath reaction in S1 is performed at a temperature of 130°C-140°C for 6h-7h. Most preferably, the oil bath temperature and time are 130°C and 6h, respectively.

[0021] The aromatic active small molecule composition obtained by the method of the present application can be used as a reaction monomer for the synthesis of polymers, such as polyurethane elastomers or phenolic aldehyde. Compared with petroleum-based reaction monomers, the polymer products synthesized by using biomass monomers such as aromatic small molecules have certain biodegradability and recyclability.

[0022] Compared with the prior art, the present application has the following beneficial effects in extracting aromatic small molecules from mulberry wood:

[0023] (1) By acid pretreatment, hemicellulose, lignin and cellulose are separated, and multiple components are efficiently utilized;

[0024] (2) By ionic liquid-like directional destruction of covalent bond action, lignin macromolecules are cracked into aromatic molecules with different molecular weights, and the synergistic effect of the acid makes the cracking efficiency better;

[0025] (3) The extraction steps are simple and safe, and the extraction reagents are low in price, reusable and pollution-free.

[0026] (4) The extracted aromatic small molecule composition has considerable data in yield, purity and activity. High hydroxyl content (aliphatic hydroxyl and aromatic hydroxyl) endows the small molecule with high reactivity, which can react with isocyanate or formaldehyde to generate polyurethane material and phenolic resin, etc., and has good application prospect. At present, it has been proved in the literature that aromatic biological polyol can successfully synthesize polyurethane elastomer, etc. After testing and analysis, the performance of the material is less and less different from that of the traditional petroleum-based product, and even in some performance aspects, it is much higher than that of the traditional product. In the face of the plight of fossil energy depletion, it is expected to replace petroleum-based polyol to realize chemical synthesis, modification and other high-value utilization by using biological polyol extracted from biomass. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 Infrared spectrum of the aromatic small molecule prepared in Example 1;

[0028] Figure 2 Nuclear magnetic resonance hydrogen spectrum of the aromatic small molecule prepared in Example 1;

[0029] Figure 3 Gel permeation chromatography (GPC) of the aromatic small molecule prepared in Example 1. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be further described below through specific examples. It should be understood that the implementation of the present application is not limited to the following examples, and any form of variation and / or change made to the present application will fall within the scope of protection of the present application.

[0031] In the present application, all parts and percentages are weight units unless specified, and the equipment and raw materials used can be purchased from the market or commonly used in the art. The methods in the following examples are conventional methods in the art unless otherwise specified.

[0032] The present application extracts high-activity aromatic small molecules from mulberry trees through acid pretreatment, so the yield and purity of the extracted molecules are key indicators of extraction efficiency. In addition, the hydroxyl content, which describes the strength of the reactivity of aromatic small molecules, is a more critical indicator.

[0033] The mass percentage of the extracted aromatic molecules in the original mulberry powder is defined as the yield. According to the formula:

[0034] wt% = M1 / M0,

[0035] Wherein, M1 represents the mass of the extracted aromatic molecules, unit g;

[0036] M0 represents the mass of the aromatic components in the original mulberry powder, unit g;

[0037] The solid residue mass containing aromatic components is defined as M2, and the mass percentage of the extracted aromatic molecules in the solid residue is defined as the extraction purity. According to the formula:

[0038] C% = M1 / M2,

[0039] wherein M1 represents the mass of the extracted aromatic molecules, in g;

[0040] M2 represents the mass of the solid residue, in g;

[0041] The hydroxyl value of the aromatic molecules can be quickly determined by the phthalation method. According to the formula:

[0042] X = [(V1-V2) x C x 56.1] / M,

[0043] wherein X represents the hydroxyl value of the aromatic molecules to be tested, in mgKOH / g;

[0044] V1 represents the amount of NaOH standard solution used in the blank test, in ml;

[0045] V2 represents the amount of NaOH standard solution used for the aromatic molecules to be tested, in ml;

[0046] C represents the concentration of the NaOH standard solution, in mol / L;

[0047] M represents the mass of the aromatic molecules to be tested, in g;

[0048] 56.1 represents the molar mass of KOH, in g / mol.

[0049] Example 1

[0050] A method for extracting an aromatic active small molecule composition from mulberry wood, the method steps are:

[0051] S1, mulberry wood is taken from the trunk of a mulberry tree in Lu, crushed into 100 mesh powder, 10 g is weighed in a beaker, 3% mass fraction of dilute sulfuric acid is added according to the solid-liquid ratio of 1:40, dissolved for 6 h, and then filtered to produce filter residue A; the ionic liquid-like composed of choline chloride and lactic acid in a molar ratio of 1:2 and the filter residue A are reacted in a volumetric flask at an oil bath temperature of 130°C for 6 h, and then ethanol is added to dissolve to obtain a mixed solution;

[0052] The amount of ionic liquid-like (choline chloride and lactic acid in a molar ratio of 1:2) is 20 times the weight of the mulberry wood powder.

[0053] S2, the obtained mixed solution is vacuum filtered, the filtrate B is poured into a beaker, and deionized water is added to dilute to generate a precipitate C; the precipitate C is washed with 10% ethanol-deionized water by volume, and then centrifuged and dried to obtain a solid residue containing a high-activity aromatic small molecule composition. It is calculated that the yield of the aromatic substance is 24.1%, the purity is 98.4%, and the hydroxyl value is 673.2 mgKOH / g.

[0054] The infrared spectrum of the prepared aromatic small molecule is shown in Figure 1 The figure shows that there are 1513, 1426 cm -1 aromatic ring skeleton vibration, 1463 cm -1 -CH3 and -CH2 C-H bending vibration, 1327 cm -1 C-O stretching vibration of S-type unit, 1117 cm -1 aromatic ring C-H in-plane bending vibration of S-type unit, 839 cm 1 C-H out-of-plane bending vibration of S-type unit, 1269 cm -1 C-O stretching vibration of G-type unit, and other aromatic characteristic vibration peaks.

[0055] The hydrogen nuclear magnetic resonance spectrum of the prepared aromatic small molecule is shown in Figure 2 The figure shows that 5.3 ppm represents the hydrogen proton Hα in the α position of the β-5 aromatic structure, and 6-8 ppm represents the hydrogen proton of the aromatic molecule.

[0056] The gel permeation chromatography (GPC) of the prepared aromatic small molecule is shown in Figure 3 The figure shows that the number average molecular weight is 632, the weight average molecular weight is 1398, the dispersion coefficient is 2.21, and the molecular weight size distribution is relatively uniform.

[0057] Examples 2-6

[0058] The mulberry wood powder is adjusted to 20 mesh, 40 mesh, 60 mesh, 80 mesh, and 120 mesh in size, and the remaining conditions are the same as in Example 1. The detected results are shown in Table 1.

[0059] Table 1

[0060] Example Powder size (mesh) Yield (wt%) Purity (C%) Hydroxyl value (mg KOH / g) 2 20 12.4 59.2 389.6 3 40 14.3 73.3 463.2 4 60 17.9 82.2 543.2 5 80 21.1 90.7 600.6 1 100 24.1 98.4 673.2 6 120 24.1 98.3 673.2

[0061] According to Table 1, the specific surface area of large-size particles is small, which reduces the solvent dissolution efficiency, so that the reaction is insufficient, and the efficiency of breaking the covalent bond by the ionic liquid-like is reduced. However, when the particle size is reduced to a certain extent, the influence of the size on the solvent dissolution performance can be ignored.

[0062] Examples 7-10

[0063] The mass fraction (wt%) of dilute sulfuric acid was replaced by 1%, 2%, 4%, 5%, respectively, and the rest of the conditions were the same as in Example 1. The results obtained are shown in Table 2.

[0064] Table 2

[0065] Example Mass fraction (wt%) Yield (wt%) Purity (C%) Hydroxyl value (mg KOH / g) 7 1％ 20.2 80.1 529.9 8 2％ 22.3 89.2 595.8 1 3％ 24.1 98.4 673.2 9 4％ 24.1 98.4 672.5 10 5％ 24.0 98.4 672.9

[0066] According to Table 2, pretreatment with a certain concentration of sulfuric acid can hydrolyze pectin, ash and hemicellulose. The hydrolysis efficiency is related to the concentration of acid. Before the limit of hydrolysis, the higher the concentration of acid, the better the hydrolysis efficiency. After exceeding the limit of hydrolysis, the concentration of acid has little effect on the purity and yield of aromatic small molecules.

[0067] Examples 11-14

[0068] The solid-liquid ratio was replaced by 1:20, 1:30, 1:50, 1:60, respectively, and the rest of the conditions were the same as in Example 1. The results obtained are shown in Table 3.

[0069] Table 3

[0070] Example Solid-liquid ratio Yield (wt%) Purity (C%) Hydroxyl value (mg KOH / g) 11 1:20 18.2 89.5 600.2 12 1:30 20.3 93.1 642.3 1 1:40 24.1 98.4 673.2 13 1:50 23.9 98.3 669.8 14 1:60 24.1 98.2 671.5

[0071] According to Table 3, the effect of acid pretreatment is related to the amount of acid added. The greater the amount of acid added, the better the hydrolysis effect of the acid. After exceeding the limit of hydrolysis, increasing the amount of acid added has little effect on the yield and purity of the extracted components.

[0072] Examples 15-17

[0073] The acid dissolution time was replaced by 2h, 4h, 8h, respectively, and the rest of the conditions were the same as in Example 1. The results obtained are shown in Table 4.

[0074] Table 4

[0075] Example Dissolution time (h) Yield (wt%) Purity (C%) Hydroxyl value (mg KOH / g) 15 2 17.8 80.6 550.8 16 4 19.9 85.7 575.9 1 6 24.1 98.4 673.2 17 8 24.0 98.4 672.9

[0076] According to Table 4, extending the acid treatment time improves the hydrolysis efficiency and the yield and purity of the product. After exceeding the limit of hydrolysis, extending the acid treatment time has little effect on the improvement.

[0077] Examples 18-19

[0078] The choline chloride was replaced by betaine, tetramethylammonium hydroxide, respectively, and the rest of the conditions were the same as in Example 1. The results obtained are shown in Table 5.

[0079] Table 5

[0080] Example Quaternary ammonium base Yield (wt%) Purity (C%) Hydroxyl value (mg KOH / g) 1 Choline chloride 24.1 98.4 673.2 18 Betaine 20.1 97.6 652.2 19 Tetramethylammonium hydroxide 18.8 96.4 645.8

[0081] According to Table 5, the hydrogen bond acceptor choline chloride has very strong proton accepting ability, can form an ion-like system containing high density of hydrogen bonds with lactic acid, has very excellent effect of dissolving lignin, can strongly break most of the connecting bonds, etc., and can obtain high yield and high purity of aromatic composition.

[0082] Examples 20-24

[0083] The lactic acid is replaced by formic acid, acetic acid, oxalic acid, tartaric acid, and malic acid, respectively, and the rest of the conditions are the same as in Example 1, and the obtained results are shown in Table 6.

[0084] Table 6

[0085]

[0086]

[0087] According to Table 6, lactic acid has strong proton providing ability due to its low pKa value and acidity, can form very strong hydrogen bonds with choline chloride, and the ion-like liquid extracted aromatic composition has excellent purity and yield.

[0088] Examples 25-27

[0089] The molar ratio of choline chloride to lactic acid is replaced by 1:1, 1:3, and 1:4, respectively, and the rest of the conditions are the same as in Example 1, and the obtained results are shown in Table 7.

[0090] Table 7

[0091] Example Molar ratio Yield (wt%) Purity (C%) Hydroxyl value (mg KOH / g) 25 1:1 17.1 89.4 583.2 1 1:2 24.1 98.4 673.2 26 1:3 24.1 98.3 672.5 27 1:4 24.2 98.5 676.5

[0092] According to Table 7, the hydrogen bond donor lactic acid dominates in the ion-like liquid, and higher content of lactic acid can provide high hydrogen bond density, and can extract high purity and high activity of aromatic composition, but the effect of too high content of lactic acid is not obvious.

[0093] Examples 28-31

[0094] The oil bath reaction temperature in S1 is replaced by 100℃, 110℃, 120℃, 130℃, and 140℃, respectively, and the rest of the conditions are the same as in Example 1, and the obtained results are shown in Table 8.

[0095] Table 8

[0096]

[0097]

[0098] According to Table 8, increasing the temperature can improve the solubility of the ionic liquid-like and the rate of breaking the covalent bond, improve the purity and activity of the product, but the reaction rate is limited by the excessive reaction temperature.

[0099] Examples 32-35

[0100] The reaction time was replaced by 4h, 5h, 7h, 8h respectively, and the rest of the conditions were the same as Example 1. The results obtained are shown in Table 9.

[0101] Table 9

[0102] Example Reaction time (h) Yield (wt%) Purity (C%) Hydroxyl value (mg KOH / g) 32 4 15.3 80.5 509.9 33 5 19.6 89.6 595.6 1 6 24.1 98.4 673.2 34 7 24.1 98.4 672.6 35 8 24.0 98.3 672.5

[0103] According to Table 9, extending the reaction time can make the ionic liquid-like and the wood fiber component fully dissolved and reacted, improve the yield and purity of the aromatic small molecule composition, but the reaction time is too long, and the improvement of the purity and yield of the aromatic small molecule composition is limited.

[0104] Examples 36-38

[0105] The good solvent ethanol was replaced by methanol, ethylene glycol, glycerol respectively, and the rest of the conditions were the same as Example 1. The results obtained are shown in Table 10.

[0106] Table 10

[0107] Example Good solvent Yield (wt%) Purity (C%) Hydroxyl value (mg KOH / g) 36 Methanol 23.1 97.7 659.8 1 Ethanol 24.1 98.4 673.2 37 Ethylene glycol 22.9 97.2 652.1 38 Glycerol 22.5 97.0 649.6

[0108] According to Table 10, ethanol has better compatibility with the mixed solution compared with other good solvents, so it can efficiently dissolve the mixed solution after the reaction, and improve the yield and purity of the aromatic component.

[0109] Examples 39-41

[0110] The volume fraction of the cleaning agent was replaced by 5%, 15%, 20% respectively, and the rest of the conditions were the same as Example 1. The results obtained are shown in Table 11.

[0111] Table 11

[0112] Example Volume fraction (%) Yield (wt%) Purity (C%) Hydroxyl value (mg KOH / g) 39 5 20.9 93.7 635.8 1 10 24.1 98.4 673.2 40 15 24.1 98.3 672.5 41 20 24.1 98.4 672.9

[0113] According to Table 11, the ethanol aqueous solution can dissolve the excess ionic liquid-like, and increasing the content of ethanol can improve the excess ionic liquid component and improve the purity of the aromatic small molecule component, but the content of ethanol is too high, and the purity improvement is not obvious.

[0114] It can be seen from the embodiment that the smaller the powder size, the more ideal the yield and purity of the final product; the concentration, dosage and dissolution time of the acid during acid pretreatment are proportional to the yield and purity of the aromatic small molecule composition, and the optimal acid concentration is 3wt%, and the dissolution time is 6h; during the ionic liquid-like dissolution and fractionation stage, the ionic liquid-like fractionation performance of choline chloride and lactic acid in a molar ratio of 1:2 is optimal, and the yield and purity of the aromatic active component are proportional to the oil bath temperature and time, and the optimal oil bath temperature and time are 130 DEG C and 6h respectively. Ethanol as a good solvent can fully dissolve the mixed solution, effectively improve the purity and yield of the extract, and the ethanol aqueous solution has excellent cleaning and purification effect, and the optimal ethanol aqueous solution component is 10%. It can be seen from the embodiment that the acid pretreatment and the ionic liquid-like cooperate with each other, and can efficiently separate hemicellulose, cellulose and lignin, and the separated cellulose is expected to be used as a reinforcing body of biomass composite material, which greatly expands the application range; meanwhile, the active aromatic small molecule with considerable yield, high purity and high hydroxyl content can be extracted and used as a reaction monomer for synthesis and modification in the chemical field, which has considerable application prospect. The extraction process has the advantages of simple steps, safe operation, recyclable reagents and the like.

[0115] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed by the embodiment, since it corresponds to the method disclosed by the embodiment, the description is relatively simple, and the related parts can be referred to the method part.

[0116] The above provides a detailed introduction to the aromatic active small molecule composition extracted from mulberry wood. The principle and implementation mode of the present application are described by applying specific examples. The above embodiment is only used to help understand the method and core idea of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the principle of the present application, the present application can be improved and modified, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A method of extracting aromatic active small molecule composition from mulberry wood, characterized by The method comprises the following steps: S1, mulberry is crushed into powder, and the filter residue A is obtained by dissolving and filtering the mulberry powder at room temperature with 3wt% dilute sulfuric acid; the filter residue A is mixed with a quasi-ionic liquid composed of choline chloride and lactic acid in a molar ratio of 1:2 and is ultrasonically treated, and then is reacted in an oil bath at 130 DEG C for 6h; after the reaction is completed, a good solvent is added to dissolve the reaction product to obtain a mixed solution; The amount of the quasi-ionic liquid is 20-25 times the weight of the mulberry powder; S2, the mixed solution obtained in S1 is vacuum filtered to obtain the filtrate B, and the filtrate B is diluted with water to form the precipitate C; the precipitate C is washed, centrifuged and dried to obtain the aromatic active small molecule composition.

2. The method of claim 1, wherein: The mulberry is at least one of Lushang, Huasang and Guangdong mulberry, and the raw material is derived from the branch, leaf or root part of the mulberry tree, and the powder size is 20-120 mesh.

3. The method of claim 1, wherein: The solid-liquid ratio of the mulberry powder to the dilute sulfuric acid is 1:20-60.

4. The method of claim 1, wherein: The dissolution time of the mulberry powder to the dilute sulfuric acid in S1 is 2-8h.

5. The method of claim 1, wherein: The good solvent is one or more of methanol, ethanol, ethylene glycol or glycerol.

6. The method of claim 1, wherein: When the precipitate C is washed in S2, the washing agent used is an ethanol aqueous solution with a volume fraction of 5-20%.

7. The method of claim 1, wherein: When the precipitate C is washed in S2, the washing agent used is an ethanol aqueous solution with a volume fraction of 10-20%.

8. An aromatic active small molecule composition obtained by the method of claim 1.

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