Rhamnolipid derivative as well as preparation method and application thereof

Abstract

The invention discloses a rhamnolipid derivative as well as a preparation method and application thereof.The rhamnolipid derivative is prepared through esterification reaction of rhamnolipid and organic acids, and a preservative is slowly released through reversible hydrolysis of an ester bond structure, so that the rhamnolipid derivative has long-acting microbial inhibition capacity; the safety problem and the long-term storage failure problem possibly caused by a traditional preservative adding mode are avoided. The rhamnolipid derivative provided by the invention can be applied to a variety of daily chemical products, especially cleaning wash supplies, and can be added instead of preservatives to a certain extent. The preparation method of the rhamnolipid derivative provided by the invention is simple and convenient in process, free of high cost and suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the field of rhamnolipids, and in particular to rhamnolipid derivatives with self-preservation properties, preparation methods and uses thereof. Background Art

[0002] Rhamnolipids are metabolites produced by Pseudomonas or Burkholderia species. They have the properties of surfactants and exist naturally in soil, water and plants. Rhamnolipids have both alkyl carbon chains and sugar structures in their structure, so they are both hydrophilic and lipophilic. The above characteristics give rhamnolipids many advantages, including: 1. Emulsification ability: it can emulsify oily substances and make them stably dispersed in the dispersed phase; 2. Enhanced cell membrane permeability: one of the functions of rhamnolipids in nature is to assist microorganisms in taking in food, mainly relying on its ability to enhance cell membrane permeability; 3. Non-toxic, harmless and degradable. Based on the above characteristics, rhamnolipids can be used as a green surfactant in the field of daily chemicals, and have been recognized by a large number of formulators.

[0003] In the field of daily chemicals, preservatives are one of the important components, which can effectively inhibit the growth and reproduction of microorganisms in cosmetics, maintain the stability of the properties of cosmetics, make them not easy to deteriorate after opening and use, and extend the shelf life. However, many preservatives are restricted or banned in the field of daily chemicals by laws and regulations of various countries due to their high sensitization (imidazolyl urea, isothiazolinone, methylchloroisothiazolinone) and potential reproductive toxicity (parabens, propylparaben) and other side effects. Other relatively safe and widely used preservatives in the daily chemical industry, such as phenoxyethanol, sodium benzoate, parahydroxyacetophenone, sodium dehydroacetate, etc., have limited preservative ability, and there is a risk of reduced preservative ability due to preservative consumption during long-term storage and use of the final product. In the current consumer concept, consumers are paying more and more attention to the raw material ingredients in daily chemical products. With the improvement of living standards, consumers' demand for safe, mild and non-irritating daily chemical products is gradually increasing, which is contradictory to the practice of adding preservatives to daily chemical products to avoid the risk of microbial contamination. In order to ensure effective antiseptic ability and reasonable shelf life requirements, the preservative components in daily chemical products will inevitably introduce risks such as irritation and allergenicity. Therefore, how to design an additive with good antiseptic ability, long-lasting antiseptic effect, no biological toxicity and low allergenicity has become one of the research hotspots of daily chemical products, especially cosmetic raw material manufacturers. Summary of the invention

[0004] In order to overcome the deficiencies in the prior art, one object of the present invention is to provide a rhamnolipid derivative that can provide effective microbial inhibition capability.

[0005] Another object of the present invention is to provide a method for preparing a rhamnolipid derivative and its use.

[0006] To achieve the object of the present invention, the following technical solutions are adopted:

[0007] A rhamnolipid derivative includes one or more of the structures shown in formula (Ⅰ) and formula (Ⅱ).

[0008]

[0009] Wherein, R1 to R8 are the same or different, and each independently represents a hydrogen atom (H) or a chemical structure containing an acyl group (-CO-), at least one of R1 to R5 in formula (Ⅰ) is not H, at least one of R6 to R8 in formula (Ⅱ) is not H, and the ranges of x, x', y, and y' in formula (Ⅰ) and formula (Ⅱ) are 5 to 15. The above chemical structure containing an acyl group (-CO-) is a structure in which the hydroxyl group in benzoic acid, hydroxybenzoic acid or sorbic acid is replaced by an oxygen atom connected to R1 to R8.

[0010] The present invention also provides a method for preparing the rhamnolipid derivative: using an organic acid and a rhamnolipid as raw materials, and preparing the rhamnolipid derivative through an esterification reaction.

[0011] The rhamnolipid can be a mixture of one or several of monosaccharide monoester, disaccharide monoester, monosaccharide diester, and disaccharide diester. Preferably, the rhamnolipid includes one or more of the substances shown in formula (Ⅲ) and formula (Ⅳ), and the ranges of x, x', y, and y' in formula (Ⅲ) and formula (Ⅳ) are 5 to 15.

[0012] Preferably, the organic acid is selected from benzoic acid or benzoate, hydroxybenzoic acid or hydroxybenzoate, sorbic acid or sorbate.

[0013]

[0014] In the preparation method provided by the present invention, the molar ratio of the hydroxyl group in the rhamnolipid to the carboxyl group in the organic acid is 1:1 to 5; preferably 1:1 to 3.

[0015] In the preparation method provided by the present invention, a catalyst is also added in the esterification reaction.

[0016] The catalyst can be one or more of concentrated sulfuric acid, sulfamic acid, p-toluenesulfonic acid, heteropolyacid, solid superacid, sulfates (such as potassium bisulfate), chlorides (such as titanium chloride, tin chloride, iron chloride, etc.), and the usage amount is 0.5% to 10% of the total mass of the reaction system.

[0017] In the preparation method provided by the present invention, the esterification reaction can be carried out in an organic solvent system, and the organic solvent used can be of any type as long as it can dissolve the materials and does not affect the reaction. In some embodiments of the present invention, the organic solvent can be one or more of N,N-dimethylformamide, chloroform, acetone, and dimethyl sulfoxide.

[0018] In the preparation method provided by the present invention, a water-carrying agent can be additionally added or not added, and the water-carrying agent can be one or more of petroleum ether, benzene, toluene, cyclohexane, chloroform, and carbon tetrachloride.

[0019] In the preparation method provided by the present invention, the addition amount of the water-carrying agent is 1% - 30% of the total mass of the reaction system.

[0020] In the preparation method provided by the present invention, the reaction temperature is usually 60 - 150 °C.

[0021] In the preparation method provided by the present invention, to ensure sufficient reaction, the water generated in the reaction system is usually removed by azeotropic distillation.

[0022] The purification method in the preparation method provided by the present invention usually uses the acid precipitation method. The specific implementation method of the acid precipitation method is as follows: after the crude product obtained by the reaction is redispersed with water, it is titrated with hydrochloric acid to pH = 1.5 - 2.0, filtered and then redispersed with water. The above steps can be repeated multiple times, and finally the precipitate is freeze-dried to obtain the rhamnolipid derivative.

[0023] A rhamnolipid composition, comprising rhamnolipid and the rhamnolipid derivative described in the present invention;

[0024] Preferably, the mass content of the rhamnolipid derivative in the composition is 0.1% - 99.9%, more preferably 1% - 99%.

[0025] The present invention also provides the use of the rhamnolipid derivative described above or the rhamnolipid derivative prepared by the preparation method described above or the rhamnolipid composition as a surfactant, preservative or preservative synergist.

[0026] The rhamnolipid derivative described above or the rhamnolipid derivative prepared by the preparation method described above or the rhamnolipid composition is applied to daily chemicals, including but not limited to cleaning and personal care products, household products, kitchen and bathroom products, and decorative products;

[0027] Preferably, it is used in cleaning and personal care products, including but not limited to shampoos, body washes, skin care products, cosmetics, facial cleansers, washing powders, and laundry detergents.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] The rhamnolipid derivative of the present invention has a rhamnolipid segment, which endows it with excellent surfactant properties and the ability to improve cell membrane permeability, enabling the preservative to have a more efficient antibacterial ability and effectively solubilize some preservatives with low solubility in the aqueous phase. After hydrolysis, the rhamnolipid of the present application can be obtained rhamnolipid and carboxylic acid with preservative effect, which can achieve long-term and slow release of the preservative. This can not only avoid the safety risks brought by a large amount of preservatives in the short term, but also be slowly released through a reversible reaction to achieve the purpose of long-term preservation. Detailed Description of the Invention

[0030] The technical solution of the present invention will be further described in detail below in conjunction with specific embodiments.

[0031] The raw materials or reagents used in the examples and comparative examples of the present invention are shown in the following table. Other raw materials or reagents are commercially available products unless otherwise specified.

[0032] Name Manufacturer Rhamnolipid Wanhua Chemical Benzoic acid Aladdin Reagent p-Hydroxybenzoic acid Aladdin Reagent Sorbic acid Aladdin Reagent N,N-Dimethylformamide Aladdin Reagent p-Toluenesulfonic acid Aladdin Reagent Cyclohexane Aladdin Reagent

[0033] The rhamnolipid used in the examples and comparative examples of the present invention refers to the product obtained by separating and purifying the concentrated fermentation broth produced by Pseudomonas aeruginosa fermentation. The preparation process is as follows:

[0034] Rhamnolipid fermentation broth: First, Pseudomonas aeruginosa was inoculated on a solid medium by the method of streak plating for strain activation; then, a single colony was picked from the activated strain and inoculated into a seed medium (composition: peptone 10.0 g / L, yeast extract 5.0 g / L, NaCl 10.0 g / L), and cultured at 30 °C for 6 h to obtain a seed solution; then the seed solution was inoculated into a fermentation medium (composition: yeast extract 5 g / L, urea 5 g / L, sodium nitrate 10 g / L, Na2HPO4 4 g / L, KH2PO4 4 g / L, CaCl2 0.4 g / L, MgSO4 2 g / L) at an inoculation amount of 1-10 vol% and cultured to obtain the rhamnolipid fermentation broth.

[0035] Separation and purification: The rhamnolipid fermentation broth was centrifuged at 6000 rpm for 15 min, the supernatant was collected and 38 wt.% concentrated hydrochloric acid was added to adjust the pH to 1.5-2.0, then it was left standing in a 4 °C refrigerator for 24 h, centrifuged again at 6000 rpm for 10 min, and the precipitate was collected; the precipitate was mixed with 3 times the volume of methanol, filtered through a 30000 Da ultrafiltration membrane, the filtrate was collected, and then the methanol was removed by a rotary evaporator at 70 °C for 3 h to obtain a paste; the paste was mixed with the same volume of water, then the pH was adjusted to above 6.0 with 3 M sodium hydroxide aqueous solution, stirred and dissolved for 2 h, pre-frozen at -80 °C for 3 h, and then freeze-dried at -86 °C for 48 h in a freeze dryer to obtain rhamnolipid.

[0036] The composition of the rhamnolipid derivative described in the examples was analyzed by a high performance liquid chromatograph (HPLC, model LC-20ADXR). The chromatographic column used was a C18 bonded phase (ODS-224), 5 μm, column length 25 cm, column diameter 4.6 mm; the mobile phase was methanol; the flow rate was 1 ml / min; and the injection volume was 20 μL.

[0037] The structure of the rhamnolipid derivative described in the examples was analyzed using nuclear magnetic resonance carbon spectroscopy.

[0038] Using the above rhamnolipid preparation method, by adjusting the parameters of the fermentation and separation and purification processes, rhamnolipids with different compositions were obtained, named RL1 and RL2 respectively, and their specific compositions (quantified by HPLC) are shown below.

[0039]

[0040]

[0041] In the above table, Rha represents the rhamnose ring, and Cn is a fatty acid chain with n carbon atoms. For example, RhaRha-C10C10 is a dirhamnolipid, and its fatty acid chains are two fatty acid chains with 10 carbon atoms each. The detailed structure is shown in formula (V).

[0042]

[0043] Unless otherwise specified, the operating methods used in the examples, comparative examples, and test examples of the present invention are all conventional methods in the art.

[0044] Unless otherwise specified, the percentages used in the examples and comparative examples of the present invention are all mass percentages.

[0045] Example 1

[0046] Preparation of rhamnolipid derivatives RL1-BA and RL2-BA

[0047] 40 g of the prepared rhamnolipid (RL1), 45 g of benzoic acid, 300 ml of N,N-dimethylformamide, 12 g of p-toluenesulfonic acid, and 40 g of cyclohexane were added to a three-necked flask, and the mixture was continuously stirred and heated to 90 °C. The reaction was carried out under reduced pressure and reflux condensation. The reaction continued for 10 h, and after the reaction was completed, the excess volatile solvent was evaporated under insulation to obtain a crude product. The crude product obtained from the reaction was redispersed in water, and the crude product was titrated to pH = 1.5 - 2.0 using 38 wt.% hydrochloric acid, and the precipitate was filtered using a 100-mesh filter. The above dispersion-titration-filtration operation was repeated 3 times, and then the obtained precipitate was freeze-dried at -83 °C. Finally, the product was obtained and named RL1-BA.

[0048] Similarly, replace rhamnolipid (RL1) in the above preparation process with RL2, keep the remaining raw materials and preparation process unchanged, and name the obtained product RL2-BA.

[0049] Use HPLC to determine the component composition of RL1-BA and RL2-BA. Since the molecular weight of the rhamnolipid derivative is larger, its retention time in the chromatographic column will be longer, so the rhamnolipid derivative can be distinguished from the unreacted rhamnolipid. The test results are as follows:

[0050]

[0051] Dissolve RL1-BA, RL2-BA, RL1, RL2, and benzoic acid in the special NMR analysis dimethyl sulfoxide reagent, with the sample concentration being 5 g / L, and use 13 13C-NMR to analyze the structure of the obtained substances. By comparing their spectra, it is found that the signal peak at 165.9 ppm is a unique signal peak of RL1-BA and RL2-BA, and this signal peak does not appear in RL1, RL2, and benzoic acid. The analysis shows that the signal peak at 165.9 ppm is the ester bond signal peak formed by the carboxyl group of benzoic acid and the hydroxyl group of rhamnolipid, proving the existence of the compound after the esterification reaction of rhamnolipid and benzoic acid in RL1-BA and RL2-BA.

[0052] Example 2

[0053] Preparation of rhamnolipid derivatives RL1-HA and RL2-HA

[0054] Add 40 g of the prepared rhamnolipid (RL1), 50 g of p-hydroxybenzoic acid, 300 ml of dimethyl sulfoxide, 20 g of 98% concentrated sulfuric acid, and 40 g of cyclohexane into a three-necked flask, continuously stir and heat up to 90 °C. The reaction is carried out under reduced pressure and condensation reflux. After heating up to 90 °C, react for 10 h. After the reaction is completed, keep warm and evaporate the excess volatile solvent to obtain the crude product. Use the same acid precipitation method as in Example 1 to treat the crude product to obtain the rhamnolipid derivative, named RL1-HA.

[0055] Similarly, replace rhamnolipid (RL1) in the above preparation process with RL2, keep the remaining raw materials and preparation process unchanged, and name the obtained product RL2-HA.

[0056] Use HPLC to determine the ratio of rhamnolipid and rhamnolipid derivative in RL1-HA and RL2-HA. The test results are as follows:

[0057]

[0058] Similar to Example 1, use 13The structure of the substance obtained by 13C-NMR analysis was analyzed by spectral analysis. The signal peak at 165.9 ppm was the ester bond signal peak formed by the carboxyl group of p-hydroxybenzoic acid and the hydroxyl group of rhamnolipid, proving the presence of the compound after the esterification reaction of rhamnolipid and p-hydroxybenzoic acid in the product.

[0059] Example 3

[0060] Preparation of rhamnolipid derivatives RL1-SA and RL2-SA

[0061] Add 40 g of the prepared rhamnolipid (RL1), 35 g of sorbic acid, 300 ml of dimethyl sulfoxide, 20 g of 98% sulfuric acid, and 40 g of cyclohexane to a three-necked flask, stir continuously and heat to 80 °C. The reaction is carried out under reduced pressure and reflux condensation. After heating to 80 °C, react for 6 h. After the reaction, keep warm and evaporate the excess volatile solvent to obtain the crude product. Use the same acid precipitation method as in Example 1 to treat the crude product to obtain the rhamnolipid derivative, named RL1-SA.

[0062] Similarly, replace the rhamnolipid (RL1) in the above preparation process with RL2, and keep the remaining raw materials and preparation process unchanged. The prepared product is named RL2-SA.

[0063] Use HPLC to determine the ratio of rhamnolipid and rhamnolipid derivative in RL1-SA and RL2-SA. The test results are as follows:

[0064]

[0065] Similar to Example 1, use 13 The structure of the substance obtained by 13C-NMR analysis was analyzed by spectral analysis. The signal peak at 166.5 ppm was the ester bond signal peak formed by the carboxyl group of sorbic acid and the hydroxyl group of rhamnolipid, proving the presence of the compound after the esterification reaction of rhamnolipid and sorbic acid in the product.

[0066] Test Example 1

[0067] Test the microbial inhibition ability of the rhamnolipid derivatives in Test Examples 1-3

[0068] Dilute the rhamnolipid or rhamnolipid derivative with water to 20%, and adjust the pH to 5.5 with sodium hydroxide. Let it stand at room temperature for 7 days. Then add the mixed bacterial liquid to each test sample, store it at 25 °C at room temperature, and take samples 7 days, 14 days, and 28 days after the inoculation of the bacterial liquid. Determine the number of colonies by the streak plate method, and repeat each test three times and take the average value.

[0069] The total concentration of the above mixed bacterial liquid in the sample after inoculation is 5.8×10 5CFU / ml, the included bacterial strains are: Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.

[0070] Table 1 Test Results of Microbial Inhibitory Ability

[0071]

[0072] After completing the above tests, store the tested samples at room temperature for 3 months, then inoculate the bacterial mixed liquid for the second time, and take samples on the 7th, 14th, and 28th days after the inoculation of the bacterial liquid. Determine the number of colonies by the method of streaking on plates, and take the average value by repeating each test three times.

[0073] The total concentration in the samples after the inoculation of the above mixed bacterial liquid is 5.8×10 5 CFU / ml, the included bacterial strains are: Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.

[0074] Table 2 Test Results of Long-term Microbial Inhibitory Ability

[0075]

[0076] As can be seen from the results in Table 1, after 28 days of microbial inoculation, the rhamnolipid derivatives RL1-BA, RL2-BA, RL1-HA, RL2-HA, RL1-SA, and RL2-SA all reached an antibacterial efficiency of >99%, while RL1 and RL2 of the single rhamnolipid did not show any antibacterial ability, proving that after introducing benzoic acid, p-hydroxybenzoic acid, or sorbic acid into the rhamnolipid structure, the obtained derivatives have excellent microbial inhibitory ability. In addition, the rhamnolipid derivatives also have long-term microbial inhibitory ability. As can be seen from the results in Table 2, 20% of the rhamnolipid derivatives gradually release organic acid preservatives during the 3-month storage process. After inoculating again 3 months after the end of the first inoculation test, their microbial inhibitory ability is significantly improved compared with the first inoculation period.

[0077] Test Example 2

[0078] Microbial Inhibitory Ability of Rhamnolipid Derivatives at Different Usage Concentrations in Test Example 1

[0079] Dilute RL1-BA and RL2-BA with water to 20%, 15%, 10%, and 5%, and adjust the pH to 5.5 with sodium hydroxide. Let it stand at room temperature for 7 days. Then add the mixed bacterial liquid to each test sample, store it at 25°C at room temperature, and take samples on the 7th, 14th, and 28th days after the inoculation of the bacterial liquid. Determine the number of colonies by the method of streaking on plates, and take the average value by repeating each test three times.

[0080] The total concentration in the samples after the inoculation of the above mixed bacterial liquid is 5.8×10 5CFU / ml, the included bacterial strains are: Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.

[0081] Table 3 Test results of the microbial inhibition ability at different concentrations of rhamnolipid derivatives

[0082]

[0083] As can be seen from the results in Table 3, rhamnolipid derivatives have excellent microbial inhibition ability, and even with a relatively small addition amount (5% rhamnolipid derivatives), they can significantly inhibit bacterial growth.

[0084] Test Example 3

[0085] Acute eye irritation of rhamnolipid derivatives in Test Example 1 on rabbits

[0086] Dilute RL1-BA with water to 10%, and adjust the pH to 5.5 using sodium hydroxide. Additionally, prepare a 1% aqueous solution of sodium benzoate. Test and evaluate the acute eye irritation of the above test samples on rabbit eyes according to the method of 《OECD Test Guideline No.405 Acute Eye Irritation / Corrosion》. The test results are as follows:

[0087] Table 4 Test results of acute eye irritation (score)

[0088]

[0089] As can be seen from the results in Table 4, the aqueous solution of benzoic acid alone has a certain degree of irritation to rabbit eyes, while by esterifying benzoic acid and binding it to rhamnolipids to form the rhamnolipid derivative RL1-BA, the irritation is significantly reduced, and it has better safety advantages in application scenarios where it comes into contact with human eyes or skin.

[0090] Example 4

[0091] Preparation of a shampoo using rhamnolipid derivatives

[0092] To further verify the actual application effect of rhamnolipid derivatives in the field of care, this example was designed. However, the scope of use of this product includes but is not limited to this example.

[0093] The shampoo formula is shown in Table 5 below. Its preparation method includes the following steps: Add each component sequentially under stirring at 800 r / min at room temperature according to the ratio, and adjust the pH value to 5.5, and stir until completely dispersed.

[0094] Table 5 Shampoo formula

[0095]

[0096]

[0097] Both the embodiment and the comparative example can achieve the normal use effect of shampoo.

[0098] Test Example 4

[0099] Testing the microbial inhibition ability of shampoo

[0100] The prepared shampoo was placed at 25°C for 7 days, and the number of microbial colonies was tested by sampling. Then, the mixed bacterial solution was added to each test sample, and the sample was stored at 25°C. The sample was taken 7, 14, and 28 days after the bacterial solution was inoculated, and the number of colonies was determined by the plate streak method. Each test was repeated three times to obtain the average value.

[0101] The total concentration of the mixed bacterial solution in the sample after inoculation was 5.8×10 5 CFU / ml, including bacteria: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus.

[0102] Table 6 Test results of microbial inhibition ability of shampoo formula

[0103]

[0104] As shown in Table 6, in the shampoo test formula, the addition of rhamnolipid alone did not significantly improve the microbial inhibition ability, while the shampoo (Example 4-1) with the addition of the rhamnolipid derivative RL1-BA showed excellent microbial inhibition ability, and the 28-day microbial inhibition level was comparable to the shampoo (Comparative Example 4-3) with the direct addition of benzoic acid. In addition, by observing Comparative Example 4-3 and Comparative Example 4-4, it was found that the microbial inhibition ability of the shampoo with both rhamnolipid and benzoic acid was better than that of the shampoo with only benzoic acid added, proving that rhamnolipid has a synergistic effect on the above preservatives.

[0105] After completing the above tests, in order to test the long-term microbial inhibition ability of the shampoo, we stored the tested samples at room temperature for 3 months, and then inoculated the bacterial mixed culture for the second time. We also took samples 7 days, 14 days, and 28 days after the inoculation of the culture solution, and determined the number of colonies by the plate streak method. Each test was repeated three times and the average value was taken.

[0106] The total concentration of the mixed bacterial solution in the sample after inoculation was 5.8×10 5 CFU / ml, including bacteria: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus.

[0107] Table 7 Results of long-term microbial inhibition test of shampoo formula

[0108]

[0109] As can be seen from the results in Table 7, after 3 months of storage at room temperature, the shampoo added with rhamnolipid derivative RL1-BA (Example 4-1) still showed excellent microbial inhibition ability, while the microbial inhibition abilities of the shampoo added with benzoic acid alone and the shampoo added with both rhamnolipid and benzoic acid (Comparative Examples 4-3 and 4-4) both decreased. The above results prove that the consumption of preservatives during long-term storage led to the decrease in the microbial inhibition ability of the shampoo in Comparative Example 2-5, while the shampoo added with rhamnolipid derivative RL1-BA can continuously release preservatives through hydrolysis, thus maintaining long-term and efficient microbial inhibition ability. In addition, the slow-release mechanism of the rhamnolipid derivative preservative can effectively avoid the irritation risk caused by high-concentration preservatives in a short time. In the field of personal care where the attention to the safety of raw materials is increasing day by day, this raw material with both high safety and excellent anti-corrosion ability has a broader application prospect.

Claims

1. A rhamnolipid derivative, characterized in that, It includes one or more of the structures shown in formula (Ⅰ) and formula (Ⅱ). Among them, R1 to R8 are the same or different, and each independently represents a hydrogen atom (H) or a chemical structure containing an acyl group (-CO-). In formula (Ⅰ), at least one of R1 to R5 is not H, and in formula (Ⅱ), at least one of R6 to R8 is not H. The ranges of x, x', y, and y' in formula (Ⅰ) and formula (Ⅱ) are 5 to 15. The chemical structure containing an acyl group (-CO-) is a structure in which the hydroxyl group in benzoic acid, hydroxybenzoic acid, or sorbic acid is replaced by an oxygen atom connected to R1 to R8.

2. A preparation method of rhamnolipid derivatives, characterized in that: Using organic acid and rhamnolipid as raw materials, a rhamnolipid derivative is prepared through an esterification reaction; The rhamnolipid includes a mixture of one or more of monosaccharide monoester, disaccharide monoester, monosaccharide diester, and disaccharide diester; Preferably, the rhamnolipid includes one or more of the substances shown in formula (Ⅲ) and formula (Ⅳ), and the ranges of x, x', y, and y' in formula (Ⅲ) and formula (Ⅳ) are 5 to 15; Preferably, the organic acid is selected from benzoic acid or benzoate, hydroxybenzoic acid or hydroxybenzoate, sorbic acid or sorbate.

3. The preparation method according to claim 2, characterized in that, The molar ratio of the hydroxyl group in the rhamnolipid to the carboxyl group in the organic acid is 1:1 to 5; preferably 1:1 to 3.

4. The preparation method according to claim 2 or 3, characterized in that, A catalyst is also added in the esterification reaction; Preferably, the catalyst is selected from one or more of concentrated sulfuric acid, sulfamic acid, p-toluenesulfonic acid, heteropolyacid, solid superacid, sulfates, and chlorides, and the usage amount is 0.5% to 10% of the total mass of the reaction system.

5. The preparation method according to any one of claims 2-4, characterized in that, The esterification reaction is carried out in an organic solvent system, and the organic solvents used are one or more of N,N-dimethylformamide, chloroform, acetone, and dimethyl sulfoxide; Preferably, a water-carrying agent is added or not added, and the water-carrying agent is one or more of petroleum ether, benzene, toluene, cyclohexane, chloroform, and carbon tetrachloride; Preferably, the addition amount of the water-carrying agent is 1% to 30% of the total mass of the reaction system; Preferably, the reaction temperature is usually 60 to 150 °C; Preferably, the product is purified by an acid precipitation method; Preferably, the acid precipitation method is that after the crude product obtained from the reaction is redispersed with water, it is titrated with hydrochloric acid to pH = 1.5 - 2.0, filtered and then redispersed with water, and the above steps are optionally repeated multiple times. Finally, the precipitate is freeze-dried to obtain the rhamnolipid derivative.

6. A rhamnolipid composition, including rhamnolipid and the rhamnolipid derivative described in claim 1 or the rhamnolipid derivative prepared by the preparation method described in any one of claims 2 - 5; Preferably, the mass content of the rhamnolipid derivative in the composition is 0.1% - 99.9%, more preferably 1% - 99%.

7. The use of the rhamnolipid derivative described in claim 1 or the rhamnolipid derivative prepared by the preparation method described in any one of claims 2 - 5 or the composition described in claim 6, as a surfactant, preservative, or preservative synergist.

8. According to the use described in claim 7, its application in daily chemicals, including but not limited to cleaning and washing products, household products, kitchen and bathroom products, and decorative products; Preferably, it is used for cleaning and washing products, including but not limited to shampoo, body wash, skin care products, cosmetics, facial cleanser products, washing powder, and laundry detergent.

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