A method for synthesizing glycerol polyoxyethylene ether fatty acid ester

Abstract

The application discloses a synthesis method of glycerin polyoxyethylene ether fatty acid ester, which comprises the following steps: taking glycerin polyoxyethylene ether and natural oil with a molar ratio of 3:1 as raw materials, and under the action of an alkaline catalyst, the mass percentage content of the alkaline catalyst in the natural oil is 0.3-0.6%, so as to obtain glycerin polyoxyethylene ether fatty acid ester. The product glycerin polyoxyethylene ether fatty acid ester can form a transparent and stable nanometer micellar system with a little blue light in water, and can be applied to personal washing and protection products and cosmetic formulations as a fat agent.

Description

Technical Field

[0001] This invention belongs to the field of surfactant preparation technology, and more specifically, relates to a method for synthesizing glycerol polyoxyethylene ether fatty acid esters. Background Technology

[0002] Glyceryl polyoxyethylene ether fatty acid esters, also known as PEG glyceryl fatty acid esters or PEG fatty acid glyceryl esters, are a class of high-performance, non-toxic, and low-irritant green surfactants. Their molecular structure includes both the structure of glyceryl fatty acid esters and the structure of hydrophilic polyoxyethylene ethers. Compared with glyceryl fatty acid esters, they have better water solubility and are also known as water-soluble oils. At the same time, they have the characteristics of being non-toxic and low-irritant like oils, and therefore have good application prospects.

[0003] Glyceryl polyoxyethylene ether fatty acid esters possess excellent emollient, lipogenic, and moisturizing properties. For example, PEG-7 glyceryl cocoate (CAS: 68201-46-7) is widely used in personal care products and cosmetics (CN113768828A, CN113576969A, CN111588664A, etc.) for its emollient, lipogenic, emulsifying, and moisturizing effects. Although glyceryl polyoxyethylene ether fatty acid esters are widely used in personal care formulations, in China, these products are currently mainly imported, such as PEG-7 glyceryl cocoate from Basf and PEG-6 caprylic / capric glyceride from Croda.

[0004] Regarding the synthesis of glycerol polyoxyethylene ether fatty acid esters, the main research route is as follows: glycerol polyoxyethylene ether and fatty acids are directly esterified to obtain glycerol polyoxyethylene ether fatty acid esters. At present, there are not many reports on the synthesis of glycerol polyoxyethylene ether fatty acid esters at home and abroad. The relevant reports that can be retrieved all adopt this method (1. Wang Zihan. Synthesis and performance study of glycerol polyoxyethylene ether fatty acid esters [D]. Jiangnan University 2021; 2. A PEG glycerol ether isomeric fatty acid ester, its preparation method and its application, CN108192091A; 3. Zhu Guohua, Yang Jingxin. Synthesis and performance study of glycerol polyoxyethylene ether oleate [J]. Progress in Fine Petrochemicals, 2001(10):1-4; 4. Zhou Xiangdong, Yang Haitao. Synthesis and application of glycerol polyoxyethylene ether oleate [J]. Dyeing and Printing Auxiliaries, 2007(07):19-20+24).

[0005] As a water-soluble oil, glycerol polyoxyethylene ether fatty acid esters typically need to achieve a certain balance between hydrophilicity and lipophilicity. They cannot be too lipophilic, resulting in an oily feel or instability in water-based formulations; nor can they be too hydrophilic, causing them to be washed away during cleansing and unable to effectively adhere to the skin or hair surface, thus failing to achieve the purposes of moisturizing, oil-binding, and hydrating. Existing research reports on the synthesis of glycerol polyoxyethylene ether fatty acid esters have limited coverage of the water-soluble properties of the products. Summary of the Invention

[0006] The purpose of this invention is to provide a method for synthesizing glycerol polyoxyethylene ether fatty acid esters.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The first aspect of the present invention provides a method for synthesizing glycerol polyoxyethylene ether fatty acid ester, comprising the following steps: using glycerol polyoxyethylene ether and natural oils in a molar ratio of 3:1 as raw materials, and under the action of an alkaline catalyst, wherein the mass percentage of the alkaline catalyst in the natural oils is 0.3 to 0.6%, to obtain glycerol polyoxyethylene ether fatty acid ester.

[0009] The method for synthesizing the glycerol polyoxyethylene ether fatty acid ester includes the following steps:

[0010] Glyceryl polyoxyethylene ether and natural oils in a molar ratio of 3:1 are heated to 90-110°C (preferably 100-110°C) under vacuum, and dehydrated for 0.5-1 h until the moisture content of the material is ≤0.1%. The vacuum is then removed, and an alkaline catalyst of 0.3-0.6% by mass of the natural oils is added. Nitrogen gas is introduced for protection, and the temperature is raised to the reaction temperature of 220-250°C (preferably 230-240°C). The mixture is stirred for 1.5-3 h (preferably 2-3 h), cooled to below 85°C, and neutralized with glacial acetic acid until the pH is 6.0-7.0 to obtain the glyceryl polyoxyethylene ether fatty acid ester.

[0011] The natural oil is selected from at least one of coconut oil (average carbon number of fatty acid chain is about 12.8), palm kernel oil (average carbon number of fatty acid chain is about 13.5), babassu oil (average carbon number of fatty acid chain is about 13.5), palm oil (average carbon number of fatty acid chain is about 16.8), sunflower seed oil (average carbon number of fatty acid chain is about 17.7), and olive oil (average carbon number of fatty acid chain is about 17.7).

[0012] The glycerol polyoxyethylene ether is selected based on the different average carbon numbers of the fatty acid chains of natural oils, and reacts with glycerol polyoxyethylene ethers of corresponding EO summation numbers: glycerol polyoxyethylene ethers reacting with coconut oil have an EO summation number of 6-8; glycerol polyoxyethylene ethers reacting with palm kernel oil or babassu oil have an EO summation number of 7-9; glycerol polyoxyethylene ethers reacting with palm oil have an EO summation number of 9-11; and glycerol polyoxyethylene ethers reacting with sunflower seed oil or olive oil have an EO summation number of 10-12.

[0013] The alkaline catalyst is selected from KOH or NaOH.

[0014] A second aspect of the present invention provides the application of the glycerol polyoxyethylene ether fatty acid ester prepared by the method described above in the preparation of lipophilic agents.

[0015] By adopting the above technical solution, the present invention has the following advantages and beneficial effects:

[0016] This invention uses natural oils and glycerol polyoxyethylene ether to prepare glycerol polyoxyethylene ether fatty acid esters. Compared with existing synthetic routes (reaction of fatty acids and glycerol polyoxyethylene ether), the cost of natural oils is lower than that of fatty acids.

[0017] To ensure the hydrophilic-lipophilic balance of the final product, this invention uses glycerol polyoxyethylene ether and natural oils for reaction, controlling the molar ratio of glycerol polyoxyethylene ether to natural oils to be 3:1. For natural oils of different sources and chain lengths, glycerol polyoxyethylene ethers with different EO addition numbers are selected for reaction, so that the final product is just soluble in water and can form a transparent and stable nanomicelle system with a slightly bluish light in water. The product is mainly monoester structure, and also has diester structure, which can be used as a fat-applying agent in personal care products and cosmetic formulations. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the infrared spectra of the product glycerol polyoxyethylene ether-7 cocoate from Example 2 and commercially available PEG-7 glycerol cocoate.

[0019] Figure 2 This is a schematic diagram showing the appearance of a 5% aqueous solution of the products prepared in Examples 1-3 and Comparative Examples 1-2.

[0020] Figure 3 This is a schematic diagram showing the appearance of a 5% aqueous solution of the products prepared in Examples 4-7.

[0021] Figure 4 This is a schematic diagram of the appearance of a 5% aqueous solution of the product prepared in Comparative Examples 3-6.

[0022] Figure 5This is a schematic diagram of the appearance of a 5% aqueous solution of the product prepared in proportions 7 to 10.

[0023] Figure 6 This is a schematic diagram of the particle size distribution of the micelle system formed by a 5% aqueous solution of the products of Examples 1 to 7. Detailed Implementation

[0024] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0025] The structure of the glycerol polyoxyethylene ether fatty acid ester product of this invention is referenced from Frank Stevens, Wang Linmei, Promising Skin Moisturizers—Ethoxylated Glyceryl Monoesters and Diesters [J]. Daily Chemical Industry Translation Series, 1991(5):4.

[0026] The reaction synthesis route in this embodiment of the invention is shown below:

[0027]

[0028] Where: x is the average number of ethylene oxide molecules polymerized on each hydroxyl group of glycerol polyoxyethylene ether, 3x is the number of ethylene oxide molecules polymerized per glycerol molecule, and R is the fatty chain of the natural oil.

[0029] Example 1

[0030] The preparation method of glycerol polyoxyethylene ether-6 cocoate includes the following steps:

[0031] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 128.16 g of glycerol polyoxyethylene ether-6 (0.36 mol, with an average ethylene oxide additivity of 6) and 83.04 g of coconut oil (0.12 mol, with an average molecular weight of 692, the same below) were added. The mixture was heated to 100 °C under stirring and vacuum conditions and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 205.22 g of glycerol polyoxyethylene ether-6 cocoate.

[0032] Example 2

[0033] The preparation method of glycerol polyoxyethylene ether-7 coconut oil ester includes the following steps:

[0034] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 144 g of glycerol polyoxyethylene ether-7 (0.36 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 7) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 220.83 g of glycerol polyoxyethylene ether-7 coconut ester.

[0035] The product obtained in this invention is a homogeneous and transparent liquid. The infrared spectrum of the glycerol polyoxyethylene ether-7 cocoate product from Example 2 was tested, and an infrared spectrum was also tested using commercially available PEG-7 glycerol cocoate as a control sample. The results are as follows: Figure 1 As shown in the figure, the infrared spectrum of the product of Example 2 is almost identical to that of commercially available PEG-7 glycerol cocoate, indicating that the expected product was obtained.

[0036] Example 3

[0037] The preparation method of glycerol polyoxyethylene ether-8 cocoate includes the following steps:

[0038] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 159.84 g of glycerol polyoxyethylene ether-8 (0.36 mol, with an average ethylene oxide additivity of 8) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions, and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 236.51 g of glycerol polyoxyethylene ether-8 coconut ester.

[0039] Example 4

[0040] The preparation method of glycerol polyoxyethylene ether-8 palm kernel oleate includes the following steps:

[0041] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 159.84 g of glycerol polyoxyethylene ether-8 (0.36 mol, with an average ethylene oxide additivity of 8) and palm kernel oil (86.64 g, 0.12 mol, with an average molecular weight of 722) were added. The mixture was heated to 100 °C under stirring and vacuum conditions and dehydrated for 0.6 h, at which point the water content of the mixture was 0.03%. The vacuum was removed, 0.28 g of NaOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2.5 h. The temperature was then lowered to approximately 80 °C, and 0.52 g of glacial acetic acid was added to neutralize to pH 6.4. The product was discharged, yielding 240.07 g of glycerol polyoxyethylene ether-8 palm kernel oleate.

[0042] Example 5

[0043] The preparation method of glycerol polyoxyethylene ether-10 palmitoleate includes the following steps:

[0044] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 191.52 g of glycerol polyoxyethylene ether-10 (0.36 mol, with an average ethylene oxide additivity of 10) and palm oil (103.2 g, 0.12 mol, with an average molecular weight of 860) were added. The mixture was heated to 105 °C under stirring and vacuum conditions, and dehydrated for 0.6 h, at which point the water content of the mixture was 0.03%. The vacuum was removed, 0.32 g of NaOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2.5 h. The temperature was then lowered to approximately 80 °C, and 0.60 g of glacial acetic acid was added to neutralize to pH 6.5. The product was discharged, yielding 288.13 g of glycerol polyoxyethylene ether-10 palm oleate.

[0045] Example 6

[0046] The preparation method of glycerol polyoxyethylene ether-11 sunflower seed oleate includes the following steps:

[0047] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, glycerol polyoxyethylene ether-11 (207.36 g, 0.36 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 11) and sunflower seed oil (106.8 g, 0.12 mol, average molecular weight 890) were added. The mixture was heated to 105 °C under stirring and vacuum conditions, and dehydrated for 0.8 h, at which point the water content of the mixture was 0.03%. The vacuum was removed, 0.6 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 230 °C, and the reaction was stirred for 3 h. The temperature was lowered to approximately 80 °C, and 0.57 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged to obtain 307.73 g of glycerol polyoxyethylene ether-11 sunflower seed oil ester.

[0048] Example 7

[0049] The preparation method of glycerol polyoxyethylene ether-12 olive oil ester includes the following steps:

[0050] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 223.2 g of glycerol polyoxyethylene ether-12 (0.36 mol, with an average ethylene oxide additivity of 12) and 108 g of olive oil (0.12 mol, with an average molecular weight of 900) were added. The mixture was heated to 110 °C under stirring and vacuum conditions and dehydrated for 0.8 h, at which point the water content of the mixture was 0.03%. The vacuum was removed, 0.6 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 230 °C, and the reaction was stirred for 3 h. The temperature was then lowered to approximately 80 °C, and 0.57 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged to obtain 324.62 g of glycerol polyoxyethylene ether-12 olive oil ester.

[0051] Comparative Example 1

[0052] The preparation method of glycerol polyoxyethylene ether-5 coconut oil ester includes the following steps:

[0053] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 112.32 g of glycerol polyoxyethylene ether-5 (0.36 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 5) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions, and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 199.23 g of glycerol polyoxyethylene ether-5 coconut ester.

[0054] Comparative Example 2

[0055] The preparation method of glycerol polyoxyethylene ether-9 coconut oil ester includes the following steps:

[0056] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, PEG-9 glycerol (175.68 g, 0.36 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 9) and coconut oil (83.04 g, 0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions, and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 252.20 g of glycerol polyoxyethylene ether-9 coconut ester.

[0057] Comparative Example 3

[0058] The preparation method of glycerol polyoxyethylene ether-7 coconut oil ester includes the following steps, wherein the molar ratio of glycerol polyoxyethylene ether to coconut oil is 2:1:

[0059] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 96 g of glycerol polyoxyethylene ether-7 (0.24 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 7) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 172.92 g of glycerol polyoxyethylene ether-7 coconut ester.

[0060] Comparative Example 4

[0061] The preparation method of glycerol polyoxyethylene ether-7 coconut oil ester includes the following steps, wherein the molar ratio of glycerol polyoxyethylene ether to coconut oil is 4:1:

[0062] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 192 g of glycerol polyoxyethylene ether-7 (0.48 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 7) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 268.61 g of glycerol polyoxyethylene ether-7 cocoate.

[0063] Comparative Example 5

[0064] The preparation method of glycerol polyoxyethylene ether-7 cocoate includes the following steps, wherein the amount of catalyst KOH used is 0.2% of the mass of the natural oil:

[0065] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 144 g of glycerol polyoxyethylene ether-7 (0.36 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 7) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.17 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.16 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 220.04 g of glycerol polyoxyethylene ether-7 coconut ester.

[0066] Comparative Example 6

[0067] The preparation method of glycerol polyoxyethylene ether-7 cocoate includes the following steps, wherein the amount of catalyst KOH used is 0.8% of the mass of the natural oil:

[0068] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 144 g of glycerol polyoxyethylene ether-7 (0.36 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 7) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.67 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.64 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 220.95 g of glycerol polyoxyethylene ether-7 cocoate.

[0069] Comparative Example 7

[0070] The preparation method of glycerol polyoxyethylene ether-7 coconut oil ester includes the following steps, wherein the catalyst is sodium ethoxide:

[0071] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 144 g of glycerol polyoxyethylene ether-7 (0.36 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 7) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of sodium ethoxide was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 240 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 220.73 g of glycerol polyoxyethylene ether-7 coconut ester.

[0072] Comparative Example 8

[0073] The preparation method of glycerol polyoxyethylene ether-7 cocoate includes the following steps, wherein the reaction temperature is 200℃:

[0074] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 144 g of glycerol polyoxyethylene ether-7 (0.36 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 7) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions, and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 200 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged, yielding 220.25 g of glycerol polyoxyethylene ether-7 coconut ester.

[0075] Comparative Example 9

[0076] The preparation method of glycerol polyoxyethylene ether-7 cocoate includes the following steps, wherein the reaction temperature is 280℃:

[0077] In a 500 mL four-necked flask equipped with a stirrer, thermometer, and vacuum device, 144 g of glycerol polyoxyethylene ether-7 (0.36 mol, glycerol polyoxyethylene ether with an average ethylene oxide additivity of 7) and 83.04 g of coconut oil (0.12 mol) were added. The mixture was heated to 100 °C under stirring and vacuum conditions and dehydrated for 0.5 h, at which point the water content of the mixture was 0.04%. The vacuum was removed, 0.45 g of KOH was added, and nitrogen gas was introduced for protection. The temperature was raised to the reaction temperature of 280 °C, and the reaction was stirred for 2 h. The temperature was then lowered to approximately 80 °C, and 0.43 g of glacial acetic acid was added to neutralize to pH 6.3. The product was discharged to obtain 220.15 g of glycerol polyoxyethylene ether-7 cocoate.

[0078] Comparative Example 10

[0079] The preparation of glycerol polyoxyethylene ether-7 laurate involves using lauric acid (C12 fatty acid) and glycerol polyoxyethylene ether-7 as raw materials, and following the method described in the literature "Wang Zihan. Synthesis and Performance Study of Glycerol Polyoxyethylene Ether Fatty Acid Esters [D]. Jiangnan University, 2021." The preparation method includes the following steps:

[0080] Weigh 40.05 g (0.1 mol) of glycerol polyoxyethylene ether-7 into a 250 mL round-bottom flask, then add 14.02 g (0.07 mol) of lauric acid and 0.32 g (0.6% of the total mass of the reactants) of p-toluenesulfonic acid monohydrate catalyst. Turn on the magnetic stirrer, turn on the vacuum pump until the vacuum reading reaches -0.1 to 0.095 MPa, and raise the temperature to 150 °C. React for 5 h. After the reaction is complete, transfer the round-bottom flask to a vacuum drying oven and dry to constant weight to obtain 52.12 g of glycerol polyoxyethylene ether-7 laurate.

[0081] Water solubility of the products prepared in the embodiments and comparative examples of the present invention: At room temperature, the products prepared in Examples 1 to 7 and Comparative Examples 1 to 10 were dissolved in deionized water to prepare an aqueous solution with a mass fraction of 5%, and the appearance was observed and recorded.

[0082] The particle size distribution of the 5% aqueous solution of the product in this embodiment was determined using a dynamic light scattering particle size analyzer. A 5% aqueous solution sample of the product was taken and measured on the dynamic light scattering analyzer. The measurement temperature was set to 25°C and held for 30 minutes. The incident angle of the light was set to 90° and the wavelength to 633nm. Each sample was measured five times, and the average value was calculated.

[0083] The water solubility of the products prepared in the embodiments and comparative examples of this invention is as follows: Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, Figure 2 The figures are schematic diagrams of the appearance of 5% aqueous solutions of the products prepared in Examples 1-3 and Comparative Examples 1-2. From left to right, the figures are Examples 1, 2, 3 and Comparative Examples 1 and 2. Figure 3 The figures are schematic diagrams of the appearance of 5% aqueous solutions of the products prepared in Examples 4 to 7. From left to right, the figures represent Examples 4, 5, 6, and 7. Figure 4 This is a schematic diagram of the appearance of a 5% aqueous solution of the products prepared in Comparative Examples 3-6, which are Comparative Examples 3, 4, 5, and 6 from left to right. Figure 5 The images show the appearance of a 5% aqueous solution of the product prepared for Comparative Examples 7-10, from left to right: Comparative Examples 7, 8, 9, and 10.

[0084] Figure 2In Comparative Example 1, glycerol polyoxyethylene ether-5 and coconut oil were reacted. Due to the low ethylene oxide addition number, the aqueous solution was cloudy and opaque, and the product had poor water solubility. In Comparative Example 2, glycerol polyoxyethylene ether-9 and coconut oil were reacted. Due to the high ethylene oxide addition number, the solution was completely clear and transparent, without blue light, and the product was too hydrophilic. Lipid-laden agents typically need to achieve a certain hydrophilic-lipophilic balance. They should not be too lipophilic, resulting in an oily feel or instability in water-based formulations; nor should they be too hydrophilic, causing them to be washed away during washing and unable to effectively adhere to the skin or hair surface, thus failing to achieve the purposes of moisturizing, lipohydrating, and hydrating. Therefore, selecting a glycerol ethoxylate with an appropriate ethylene oxide addition number to react with oils is crucial to achieving a good hydrophilic-lipophilic balance in the product.

[0085] pass Figure 2 and Figure 3 It can be seen that the aqueous solutions of the products prepared in Examples 1-7 are all transparent solutions with a slightly bluish tint. Compared to Example 2, Comparative Example 3 used a molar ratio of glycerol polyoxyethylene ether and coconut oil of 2:1 as reactants, and its aqueous solution was cloudy and opaque. Figure 4 The product's water solubility significantly decreased. Comparative Example 4 used a 4:1 molar ratio of glycerol polyoxyethylene ether and coconut oil as reactants, and its product had excellent water solubility, with a completely clear and transparent aqueous solution without blue light; the product was also too hydrophilic. Comparative Example 5 used KOH as a catalyst, with the catalyst accounting for 0.2% of the natural oil by mass. Its product's aqueous solution was noticeably cloudy, possibly due to insufficient catalyst dosage, resulting in incomplete reaction between coconut oil and glycerol polyoxyethylene ether, with residual coconut oil causing turbidity. Comparative Example 6 used KOH as a catalyst, with the catalyst accounting for 0.8% of the natural oil by mass. Its aqueous solution was slightly yellowish, possibly due to the presence of excessive catalyst, leading to an overly rapid reaction and a yellowish product color. Comparative Example 7... Figure 5 Using sodium ethoxide as a catalyst, the aqueous solution of the product was noticeably turbid, possibly due to the low catalytic efficiency of sodium ethoxide, resulting in incomplete reaction of the coconut oil and ultimately causing turbidity after dissolving in water. Comparative Example 8 used a lower reaction temperature of 200℃, and its aqueous solution was turbid, possibly due to insufficient temperature and incomplete reaction. Comparative Example 9 used a higher reaction temperature of 280℃, and its aqueous solution was transparent and yellowish, possibly due to the high temperature causing excessively rapid reaction or oil denaturation, resulting in a yellowish product color. Comparative Example 10 prepared glycerol polyoxyethylene ether fatty acid esters using glycerol polyoxyethylene and lauric acid as raw materials, with p-toluenesulfonic acid monohydrate as the catalyst. Its aqueous solution was completely clear and transparent, without any blue light.

[0086] According to the Tyndall effect, the bluish tint of the solution indicates the formation of nanoscale aggregates. The particle size distribution of the aqueous solution of the product from the examples was tested using dynamic light scattering technology. Figure 6 As shown, Figure 6 This is a schematic diagram of the particle size distribution of the micelle system formed by a 5% aqueous solution of the products from Examples 1-7. As can be seen from the figure, the average particle size is 100-300 nm, indicating a stable nanomicelle system.

[0087] Application Example 1

[0088] The glycerol polyoxyethylene ether fatty acid esters obtained in the embodiments of the present invention have good hydrophilic-lipophilic balance and can be used as lipophilic agents or emollients in personal care formulations. The glycerol polyoxyethylene ether-7 coconut ester obtained in Example 2 was added as a lipophilic agent to a hand sanitizer formulation, as shown in Table 1. The same formulation without the addition of glycerol polyoxyethylene ether-7 coconut ester was used as a comparative example.

[0089] To compare the lipid-replenishing effects of the hand sanitizers in Application Example 1 and Comparative Example 1 after washing, the lipid content of the test skin surface was measured using a Cutometerdual MPA 580 skin elasticity tester. A 60mm × 60mm piece of processed pigskin was used as the test skin. First, the lipid content of the test skin surface was determined to be 0% before washing. The hand sanitizers prepared in Application Example 1 and Comparative Example 1 were diluted 10 times with water and stirred until completely dissolved. Then, 5g of the diluted solution was evenly poured onto a 50mm × 60mm cotton pad and wiped once from top to bottom on the test skin. After the moisture had naturally dried, the lipid content of the test skin surface was measured and compared again. The above experiment was repeated three times, and the average value was taken.

[0090] Table 1. Application of glyceryl polyoxyethylene ether-7 cocoate obtained in Example 2 in concentrated hand sanitizer formulations.

[0091]

[0092] Table 2. Lipid-adding performance test results of Application Example 1 and Application Comparative Example 1

[0093]

[0094]

[0095] As can be seen from Table 2, Comparative Example 1 (without glyceryl polyoxyethylene ether-7 cocoate) had no lipogenic effect, while Example 1 (containing glyceryl polyoxyethylene ether-7 cocoate) had a significant lipogenic effect. This indicates that the product obtained in the embodiments of the present invention has good lipogenic properties and can be used as a lipogenic agent in personal care formulations.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for synthesizing glycerol polyoxyethylene ether fatty acid esters, characterized in that, Includes the following steps: Glyceryl polyoxyethylene ether and natural oils in a molar ratio of 3:1 are heated to 90-110°C under vacuum and dehydrated for 0.5-1 h until the moisture content of the material is ≤0.1%. The vacuum is then removed, and an alkaline catalyst of 0.3-0.6% by mass of the natural oils is added. Nitrogen gas is introduced for protection, and the temperature is raised to the reaction temperature of 220-250°C. The mixture is stirred and reacted for 1.5-3 h. The temperature is then lowered to below 85°C, and glacial acetic acid is added to neutralize the mixture until the pH reaches 6.0-7.0, thus obtaining the glyceryl polyoxyethylene ether fatty acid ester. The natural oil is selected from at least one of coconut oil, palm kernel oil, babassu oil, palm oil, sunflower seed oil, and olive oil; The glycerol polyoxyethylene ether is selected based on the different average carbon numbers of the fatty acid chains of natural oils, and reacts with glycerol polyoxyethylene ethers of corresponding EO summation numbers: glycerol polyoxyethylene ethers reacting with coconut oil have an EO summation number of 6-8; glycerol polyoxyethylene ethers reacting with palm kernel oil or babassu oil have an EO summation number of 7-9; glycerol polyoxyethylene ethers reacting with palm oil have an EO summation number of 9-11; and glycerol polyoxyethylene ethers reacting with sunflower seed oil or olive oil have an EO summation number of 10-12.

2. The method for synthesizing glycerol polyoxyethylene ether fatty acid ester according to claim 1, characterized in that, The alkaline catalyst is selected from KOH or NaOH.

3. The use of a glycerol polyoxyethylene ether fatty acid ester prepared by the method of claim 1 or 2 in the preparation of a fat-additive.

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