Method for preparing a full-biological surfactant by using rhamnose waste liquid as raw material and application thereof

Abstract

The application discloses a method for preparing a full-biological surfactant by using rhamnose waste liquid as raw material and application thereof, and comprises the following steps: stirring uniformly rhamnose waste liquid containing 3-hydroxydecanoic acid and an alkaline catalyst in a reaction kettle, slowly introducing ethylene oxide into the reaction kettle under inert gas protection condition after heating to a certain temperature, adding acetic acid for neutralization after the reaction is completed, and obtaining 3-hydroxydecanoic acid polyoxyethylene ether. The application aims to prepare the full-biological surfactant 3-hydroxydecanoic acid polyoxyethylene ether by using the rhamnose waste liquid, on the one hand, the main component 3-hydroxydecanoic acid in the rhamnose waste liquid can be reused, the product added value is increased, and the waste liquid discharge is reduced, and the application is more environment-friendly; on the other hand, the method is simple in operation, low in cost, the prepared surfactant is more natural, green and safe.

Description

Technical Field

[0001] This invention belongs to the field of biochemistry, specifically relating to a method for preparing a fully bio-based surfactant using rhamnose waste liquid as a raw material and its application. Background Technology

[0002] Rhamnose, also known as 6-deoxy-L-mannose, is a substance widely found in plant polysaccharides, glycosides, plant gums, and bacterial polysaccharides, with a sweetness approximately 33% that of sucrose. Rhamnose has various industrial applications; it can be used as a sweetener, a component in the production of flavorings and fragrances, and for measuring intestinal permeability. Currently, the preparation of rhamnose from rhamnose esters via hydrolysis under acidic conditions is an important and feasible industrial route (e.g., patents US4933281A and US5550227A). However, this route generates an oily waste liquid, whose main components include various hydroxyalkyl acids, such as 3-hydroxydecanoic acid, 3-hydroxydecanoic acid dimer, and 3-hydroxyoctanoic acid. Separating the organic matter from the rhamnose waste liquid using distillation is not only energy-intensive but also difficult, hindering economical production; treating it as waste liquid increases treatment costs and wastes significant resources. Therefore, developing the reuse of organic matter in rhamnose waste liquid during the hydrolysis of rhamnose lipids to prepare rhamnose is of great significance.

[0003] Surfactants are important chemical products widely used in detergents, cleaning agents, personal care products, food industry, pharmaceutical industry, and many other fields. Traditional surfactants are mostly synthesized from petrochemical products, leading to environmental pollution and resource waste. With increasing environmental awareness and the growing demand for sustainable development, bio-based surfactants have become a research and development hotspot due to their advantages such as being derived from renewable resources, being environmentally friendly, and having a wide range of applications. Existing bio-based surfactants are mainly prepared through methods such as microbial fermentation, enzyme catalysis, and natural biological extraction. For example, microbial fermentation can produce bio-based surfactants such as fatty acid methyl esters and monoglycerides; enzyme catalysis can synthesize bio-based surfactants such as monoglycerides, glycolipids, phospholipids, and alkyl glycosides; and phospholipids and lecithin can be extracted from natural biological raw materials such as egg yolks or soybeans. However, microbial fermentation suffers from problems such as complex fermentation processes, long cycles, and low yields; enzyme catalysis faces challenges such as high enzyme costs and difficulty in obtaining enzymes, and easy enzyme inactivation; and natural biological extraction methods suffer from limited resources, complex extraction processes, and low content of active ingredients. In summary, the bio-based surfactants synthesized using the above methods have limitations such as high production costs, low production efficiency, and difficulties in product separation. Therefore, developing a green, environmentally friendly, low-cost, and high-efficiency method for preparing bio-based surfactants is an urgent problem to be solved in this field. Summary of the Invention

[0004] To address the above technical problems, this invention proposes a method for synthesizing a fully bio-based surfactant, 3-hydroxydecanoic acid polyoxyethylene ether, using 3-hydroxydecanoic acid from rhamnose waste liquid as a raw material. On the one hand, this method can reuse 3-hydroxydecanoic acid, the main component of rhamnose waste liquid, increasing product added value and reducing waste liquid discharge, making it more environmentally friendly. On the other hand, this method is simple to operate, low in cost, and the prepared surfactant is more natural, green, and safe.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] A method for preparing a fully bio-based surfactant using rhamnose waste liquid as a raw material, the method comprising the following steps:

[0007] Rhamnose waste liquid containing 3-hydroxydecanoic acid and an alkaline catalyst were added to a reaction vessel and stirred evenly. Under inert gas protection, the mixture was heated to a certain temperature and then ethylene oxide was slowly introduced to carry out the polymerization reaction. After the reaction was completed, acetic acid was added for neutralization to obtain 3-hydroxydecanoic acid polyoxyethylene ether.

[0008] As a preferred embodiment, the composition of the rhamnose waste liquid includes: 60-70 wt% 3-hydroxydecanoic acid, 5-10 wt% 3-hydroxydecanoic acid dimer, 5-10 wt% 3-hydroxyoctanoic acid, and 10-20 wt% other components.

[0009] As a preferred embodiment, the rhamnose waste liquid can first be concentrated to obtain a 3-hydroxydecanoic acid solution, and then mixed with an alkaline catalyst. The concentration process can be carried out by distillation, as described in patent CN117756754A. Specifically, the distillation temperature is 100–200°C, preferably 120–170°C; the distillation pressure is 0.1–5 kPaA, preferably 0.5–3 kPaA.

[0010] As a preferred embodiment, the alkaline catalyst is selected from one or more of sodium hydroxide, potassium hydroxide, sodium methoxide, and potassium methoxide, with potassium hydroxide being preferred.

[0011] As a preferred embodiment, the amount of alkaline catalyst is 0.1% to 1% of the mass of 3-hydroxydecanoic acid, preferably 0.3% to 0.6%.

[0012] As a preferred embodiment, the inert gas is nitrogen.

[0013] As a preferred embodiment, the polymerization reaction temperature is 120–180°C, preferably 140–160°C; the reaction pressure is 0.05–0.3 MPaG, preferably 0.1–0.2 MPaG.

[0014] As a preferred embodiment, the molar ratio of 3-hydroxydecanoic acid to ethylene oxide is 1:5 to 1:14, preferably 1:8 to 1:12.

[0015] As a preferred embodiment, the ethylene oxide is fed for 0.5 to 3 hours, preferably 1 to 2 hours.

[0016] As a preferred embodiment, the polymerization reaction time is 1 to 5 hours, preferably 2 to 4 hours, and the polymerization reaction time does not include the aforementioned ethylene oxide feeding time.

[0017] As a preferred embodiment, the pH of the neutralized acetic acid is 7-8, and the neutralization temperature is 70-80°C.

[0018] Another object of the present invention is to provide a fully bio-based surfactant, 3-hydroxydecanoic acid polyoxyethylene ether.

[0019] A fully bio-based surfactant, 3-hydroxydecanoic acid polyoxyethylene ether, was prepared using the method described above.

[0020] Another object of the present invention is to provide the application of the above-mentioned fully bio-based surfactant 3-hydroxydecanoic acid polyoxyethylene ether in the field of daily chemical products, preferably in the fields of detergents, cleaning agents, and personal care products.

[0021] The beneficial effects of the technical solution of this invention are as follows:

[0022] (1) A novel surfactant is synthesized in one step. The raw material, rhamnose waste liquid, comes from natural raw materials, making the prepared surfactant 3-hydroxydecanoic acid polyoxyethylene ether more natural, green and safe. The synthesis process is simple and the raw material cost is low.

[0023] (2) The synthesis of 3-hydroxydecanoic acid polyoxyethylene ether, a fully bio-based surfactant, using rhamnose waste liquid not only solves the problem of waste liquid treatment, but also realizes waste utilization, improves atom utilization rate, and increases product added value. Detailed Implementation

[0024] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0025] The main analytical instruments and surfactant performance testing methods used in the embodiments of this invention are as follows:

[0026] Liquid Chromatography (HPLC): Instrument model: Agilent Technologies 1200 series; Column: C18; Column temperature: 40℃; Mobile phase: acetonitrile and 0.03wt% aqueous phosphoric acid solution; Flow rate: 0.8 mL / min; UV detector wavelength: 285 nm. Quantification was performed using the external standard method. Before injection, the sample was appropriately diluted with acetonitrile.

[0027] Gas chromatography: The gas chromatograph was an Agilent 1200 series. The initial temperature was 150℃, held for 2 min, and then programmed to increase to 280℃ at a rate of 15℃ / min, held for 5 min. The vaporization chamber temperature was 280℃, and the detection chamber temperature was 280℃. FID detection was used. The injection volume was 0.2 μL.

[0028] Turbidity point test: The turbidity point test shall be performed in accordance with the method shown in GB / T 5559-2010.

[0029] Wetting force test: The wetting force test shall be conducted in accordance with the method shown in the national standard GB / T 11983-2008.

[0030] Surface tension test: The surface tension test was performed according to the method shown in the national standard GB / T 22237-2008.

[0031] Foam performance test: Instrument model: Roche foam analyzer XH-2152, temperature: 40℃, solution concentration: 0.25%.

[0032] The main raw materials used in the embodiments of this invention are shown below. Unless otherwise specified, all other raw materials were obtained through ordinary commercial channels:

[0033] Rhamnolipid aqueous solution, 40 wt%, purchased from Evonik Specialty Chemicals (Shanghai) Co., Ltd.

[0034] Sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide, acetic acid, and concentrated sulfuric acid, analytical grade, were purchased from Aladdin Reagent Co., Ltd.

[0035] Preparation Example 1: Preparation of Rhamnose Waste Liquid

[0036] 1000g of a 40% rhamnolipin aqueous solution was mixed with 1650g of pure water to prepare a 15% rhamnolipin aqueous solution. Then, 80g of concentrated sulfuric acid was added and thoroughly mixed before being added to a high-pressure reactor. The reactor was purged with nitrogen to 0.5MPaG, and then heated to 140℃. After reacting at this temperature for 3 hours, the heating was stopped. After the temperature dropped to 25℃, stirring was stopped, the reaction solution was discharged, and after standing for 30 minutes, the oil and water phases were separated to obtain an oil phase containing 3-hydroxydecanoic acid and an aqueous phase containing rhamnosine. The oil phase was the rhamnosine waste liquid. Liquid chromatography analysis showed that its composition was: 68wt% 3-hydroxydecanoic acid, 8wt% 3-hydroxydecanoic acid dimer, 5% 3-hydroxyoctanoic acid, and 19wt% other components.

[0037] Preparation Example 2: Separation of 3-hydroxydecanoic acid from rhamnose waste liquid

[0038] The rhamnose waste liquid from Preparation Example 1 was distilled at 120°C and 3.0 kPa A to obtain a 3-hydroxydecanoic acid solution with a purity of 93 wt%.

[0039] Example 1

[0040] 202.4 g of the 3-hydroxydecanoic acid solution and 0.38 g of potassium hydroxide from Preparation Example 2 were added to a reaction vessel and stirred for 10 minutes to mix evenly. Nitrogen gas was introduced into the reaction vessel, and after the air was completely replaced, the temperature inside the reaction vessel was heated to 80°C and treated at a pressure of -0.08 MPa for 30 minutes to remove moisture from the system. Then, 396.5 g of ethylene oxide was continuously added to the reaction vessel over 1 hour to carry out the polymerization reaction, controlling the reaction temperature at 130°C and the reaction pressure at 0.15 MPaG. After the ethylene oxide was completely added, the reaction continued for 2 hours. After the reaction was completed, the temperature was lowered to 70°C, and acetic acid was added to neutralize to pH 7.0 to obtain the 3-hydroxydecanoic acid polyoxyethylene ether product. The ethylene oxide conversion rate was tested and analyzed to be 91.1%. The performance test results of the 3-hydroxydecanoic acid polyoxyethylene ether product are shown in Table 1.

[0041] Table 1 Performance test results of 3-hydroxydecanoic acid polyoxyethylene ether in Example 1

[0042]

[0043] Example 2

[0044] 202.4 g of the 3-hydroxydecanoic acid solution and 0.75 g of potassium hydroxide from Preparation Example 2 were added to a reaction vessel and stirred for 10 minutes to mix evenly. Nitrogen gas was introduced into the reaction vessel, and after the air was completely replaced, the temperature inside the reaction vessel was heated to 80°C and treated at a pressure of -0.08 MPa for 30 minutes to remove moisture from the system. Then, 528.6 g of ethylene oxide was continuously added to the reaction vessel over 2 hours to carry out the polymerization reaction, controlling the reaction temperature at 140°C and the reaction pressure at 0.15 MPaG. After the ethylene oxide was completely added, the reaction continued for 3 hours. After the reaction was completed, the temperature was lowered to 70°C, and acetic acid was added to neutralize to pH 7.0 to obtain the 3-hydroxydecanoic acid polyoxyethylene ether product. The ethylene oxide conversion rate was tested and analyzed to be 95.5%. The performance test results of the 3-hydroxydecanoic acid polyoxyethylene ether product are shown in Table 2.

[0045] Table 2 Performance test results of 3-hydroxydecanoic acid polyoxyethylene ether in Example 2

[0046]

[0047]

[0048] Example 3

[0049] 202.4 g of the 3-hydroxydecanoic acid solution and 0.56 g of potassium hydroxide from Preparation Example 2 were added to a reaction vessel and stirred for 10 minutes to mix evenly. Nitrogen gas was introduced into the reaction vessel, and after the air was completely replaced, the temperature inside the reaction vessel was heated to 80°C and treated at a pressure of -0.08 MPa for 30 minutes to remove moisture from the system. Then, 484.6 g of ethylene oxide was continuously added to the reaction vessel over 2 hours to carry out the polymerization reaction, controlling the reaction temperature at 150°C and the reaction pressure at 0.2 MPaG. After the ethylene oxide was completely added, the reaction continued for 2 hours. After the reaction was completed, the temperature was lowered to 70°C, and acetic acid was added to neutralize to pH 7.0 to obtain the 3-hydroxydecanoic acid polyoxyethylene ether product. The ethylene oxide conversion rate was tested and analyzed to be 98.8%. The performance test results of the 3-hydroxydecanoic acid polyoxyethylene ether product are shown in Table 3.

[0050] Table 3 Performance test results of 3-hydroxydecanoic acid polyoxyethylene ether in Example 3

[0051]

[0052] Example 4

[0053] 202.4 g of the 3-hydroxydecanoic acid solution and 0.75 g of potassium hydroxide from Preparation Example 2 were added to a reaction vessel and stirred for 10 minutes to mix evenly. Nitrogen gas was introduced into the reaction vessel, and after the air was completely replaced, the temperature inside the reaction vessel was heated to 80°C and treated at a pressure of -0.08 MPa for 30 minutes to remove moisture from the system. Then, 308.4 g of ethylene oxide was continuously added to the reaction vessel over 3 hours to carry out the polymerization reaction, controlling the reaction temperature at 140°C and the reaction pressure at 0.2 MPaG. After the ethylene oxide was completely added, the reaction continued for 2 hours. After the reaction was completed, the temperature was lowered to 70°C, and acetic acid was added to neutralize to pH 7.0 to obtain the 3-hydroxydecanoic acid polyoxyethylene ether product. The ethylene oxide conversion rate was 100% according to the test analysis. The performance test results of the 3-hydroxydecanoic acid polyoxyethylene ether product are shown in Table 4.

[0054] Table 4. Performance tests of 3-hydroxydecanoic acid polyoxyethylene ether in Example 4

[0055]

[0056] Example 5

[0057] 202.4 g of the 3-hydroxydecanoic acid solution and 1.1 g of potassium hydroxide from Preparation Example 2 were added to the reactor and stirred for 10 minutes to mix evenly. Nitrogen gas was introduced into the reactor, and after the air was completely replaced, the temperature inside the reactor was heated to 80°C and treated at a pressure of -0.08 MPa for 30 minutes to remove moisture from the system. Then, 396.5 g of ethylene oxide was continuously added to the reactor over 2 hours to carry out the polymerization reaction, controlling the reaction temperature at 150°C and the reaction pressure at 0.1 MPaG. After the ethylene oxide was completely added, the reaction continued for 3 hours. After the reaction was completed, the temperature was lowered to 70°C, and acetic acid was added to neutralize to pH 7.0 to obtain the 3-hydroxydecanoic acid polyoxyethylene ether product. The ethylene oxide conversion rate was 100% according to the test analysis. The performance test results of the 3-hydroxydecanoic acid polyoxyethylene ether product are shown in Table 5.

[0058] Table 5 Performance test results of 3-hydroxydecanoic acid polyoxyethylene ether in Example 5

[0059]

[0060] Example 6

[0061] 202.4 g of the 3-hydroxydecanoic acid solution and 0.94 g of potassium hydroxide from Preparation Example 2 were added to the reactor and stirred for 10 minutes to mix evenly. Nitrogen gas was introduced into the reactor, and after the air was completely replaced, the temperature inside the reactor was heated to 80°C and treated at a pressure of -0.08 MPa for 30 minutes to remove moisture from the system. Then, 440.5 g of ethylene oxide was continuously added to the reactor over 2 hours to carry out the polymerization reaction, controlling the reaction temperature at 145°C and the reaction pressure at 0.15 MPaG. After the ethylene oxide was completely added, the reaction continued for 4 hours. After the reaction was completed, the temperature was lowered to 70°C, and acetic acid was added to neutralize to pH 7.0 to obtain the 3-hydroxydecanoic acid polyoxyethylene ether product. The ethylene oxide conversion rate was 100% according to the test analysis. The performance test results of the 3-hydroxydecanoic acid polyoxyethylene ether product are shown in Table 6.

[0062] Table 6 Performance test results of 3-hydroxydecanoic acid polyoxyethylene ether in Example 6

[0063]

[0064] Comparative Example 1

[0065] AEO-9, chemically known as fatty alcohol polyoxyethylene ether, is a nonionic surfactant. It is formed by the addition reaction of natural fatty alcohols with ethylene oxide. Due to its excellent emulsifying, dispersing, detergency, cleaning, and wetting properties, it is widely used in cosmetics, detergents, and industrial cleaning agents. The performance of the AEO-9 product (purchased from Beijing Innocare Technology Co., Ltd.) was tested using the same test methods as in the examples, and the results are shown in Table 7.

[0066] Table 7 shows the performance test results of AEO-9 in Comparative Example 1.

[0067] Test Items AEO-9 product test concentration Test temperature result Cloud point 2.50wt% — 79℃ Wetting power 0.10wt% 25℃ 85s Surface tension 0.10wt% 25℃ 31.21mN / m Foam performance 0.25wt% 40℃ 180mm

[0068] The 3-hydroxydecanoic acid polyoxyethylene ether product prepared in the examples is derived from 3-hydroxydecanoic acid in rhamnose waste liquid. This not only enables the utilization of waste liquid and increases the added value of the product, but also provides the 3-hydroxydecanoic acid polyoxyethylene ether product with similar or even better performance than AEO-9. Furthermore, the 3-hydroxydecanoic acid polyoxyethylene ether product prepared by this invention is more natural, green, and safe, and has potential applications in the fields of detergents, cleaning agents, and personal care products.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a fully bio-based surfactant using rhamnose waste liquid as a raw material, characterized in that, The method includes the following steps: Rhamnose waste liquid containing 3-hydroxydecanoic acid and an alkaline catalyst were added to a reaction vessel and stirred evenly. Under inert gas protection, the mixture was heated to a certain temperature and then ethylene oxide was slowly introduced to carry out the polymerization reaction. After the reaction was completed, acetic acid was added for neutralization to obtain 3-hydroxydecanoic acid polyoxyethylene ether.

2. The method according to claim 1, characterized in that, The composition of the rhamnose waste liquid includes: 60-70 wt% 3-hydroxydecanoic acid, 5-10 wt% 3-hydroxydecanoic acid dimer, 5-10 wt% 3-hydroxyoctanoic acid, and 10-20 wt% other components.

3. The method according to claim 1, characterized in that, The alkaline catalyst is selected from one or more of sodium hydroxide, potassium hydroxide, sodium methoxide, and potassium methoxide.

4. The method according to claim 3, characterized in that, The amount of alkaline catalyst used is 0.1% to 1% of the mass of 3-hydroxydecanoic acid.

5. The method according to claim 4, characterized in that, The amount of alkaline catalyst used is 0.3% to 0.6% of the mass of 3-hydroxydecanoic acid.

6. The method according to claim 1, characterized in that, The polymerization reaction temperature is 120–180°C, and the reaction pressure is 0.05–0.3 MPaG.

7. The method according to claim 6, characterized in that, The polymerization reaction temperature is 140–160°C, and the reaction pressure is 0.1–0.2 MPaG.

8. The method according to claim 1, characterized in that, The molar ratio of 3-hydroxydecanoic acid to ethylene oxide is 1:5 to 1:

14.

9. The method according to claim 8, characterized in that, The molar ratio of 3-hydroxydecanoic acid to ethylene oxide is 1:8 to 1:

12.

10. The method according to claim 1, characterized in that, The ethylene oxide is fed for 0.5-3 hours; the polymerization reaction takes 1-5 hours.

11. The method according to claim 10, characterized in that, The ethylene oxide is fed in for 1 to 2 hours, and the polymerization reaction takes 2 to 4 hours.

12. The method according to claim 1, characterized in that, The neutralization pH of the acetic acid is 7-8, and the neutralization temperature is 70-80℃.

13. The method according to any one of claims 1-12, characterized in that, The rhamnose waste liquid containing 3-hydroxydecanoic acid was concentrated to obtain a 3-hydroxydecanoic acid solution, which was then mixed with an alkaline catalyst and added to the reaction vessel.

14. The method according to claim 13, characterized in that, The concentration process is distillation, with a distillation temperature of 100-200℃ and a distillation pressure of 0.1-5 kPaA.

15. A fully bio-based surfactant, 3-hydroxydecanoic acid polyoxyethylene ether, wherein the 3-hydroxydecanoic acid polyoxyethylene ether is prepared by the method according to any one of claims 1-14.

16. The application of the fully bio-based surfactant 3-hydroxydecanoic acid polyoxyethylene ether according to claim 15 in the fields of detergents, cleaning agents, and personal care products.

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