High monoester content sucrose fatty acid esters and methods for their preparation

Abstract

The application discloses sucrose fatty acid ester with high monoester content and a preparation method thereof. The preparation method is as follows: taking sucrose fatty acid ester crude product and / or sucrose fatty acid ester finished product as a crystallization substrate, taking an ester solvent or a mixed solvent of the ester solvent and an alkane solvent as a crystallization solvent, dissolving the crystallization substrate in the crystallization solvent at a predetermined dissolving temperature, cooling the crystallization substrate to a predetermined crystallization temperature after the dissolving, and obtaining sucrose fatty acid ester with high monoester content through filtering, washing and drying after crystallization. The monoester content of the sucrose fatty acid ester product can be significantly improved, the monoester content can be increased by about 8-20 wt% through each crystallization, and the monoester content of the product can be increased to more than 95 wt% through repeated crystallization, so that a more efficient, simple, environment-friendly and low-cost purification method is provided.

Description

Technical Field

[0001] This invention relates to the technical field of sucrose fatty acid ester preparation, and more specifically, to a sucrose fatty acid ester with high monoester content and its preparation method. Background Technology

[0002] Sucrose fatty acid esters, also known as sucrose fatty acid esters or simply SEs, are excellent nonionic surfactants. Due to their non-toxicity, non-irritation, easy biodegradability, and good surface properties, they are widely used in food, pharmaceuticals, daily chemicals, textiles, and agriculture. Their preparation generally involves a transesterification reaction between sucrose and an alkyl fatty acid ester, followed by separation to obtain the reaction products. Because sucrose contains eight free -OH groups, transesterification can produce various products ranging from monoesters to octaesters. Therefore, sucrose fatty acid ester products are generally mixtures containing monoesters, diesters, triesters, and polyesters, as shown below:

[0003]

[0004] Note: Substituents R1-R8 are: CH3(CH2) n The CO- or -H group must be at least one of CH3 (CH2). n CO-; The structure of the monoester is such that one of the groups in R1 to R8 is CH3(CH2). n CO-, the remaining seven are: -H. The diester structure has two groups in R1 to R8: CH3(CH2). n CO-, the remaining six are: -H. The structure of the triester is that three of the groups in R1 to R8 are CH3(CH2). n CO-, the other five are: -H.

[0005] Sucrose fatty acid esters use free hydroxyl groups as hydrophilic groups and the carbon chain portion of fatty acids as lipophilic groups. Based on the number of esterifications of sucrose hydroxyl groups, a series of sucrose fatty acid ester products with different HLB values ​​(1-16) ranging from lipophilic to hydrophilic can be obtained. The higher the content of monoesters, the higher the HLB value, and the stronger the hydrophilicity; the higher the content of diesters and triesters, the lower the HLB value, and the stronger the lipophilicity.

[0006] With the increasing application and widespread use of sucrose fatty acid esters, it has been found that high quality requirements are placed on sucrose fatty acid esters in many applications, especially in the pharmaceutical, food, and cosmetic fields. These requirements not only demand low impurity content in sucrose fatty acid esters, but also require that the distribution of sucrose monoesters, sucrose diesters, and sucrose polyesters be within a certain range to achieve optimal performance.

[0007] Current industrial methods for producing sucrose fatty acid esters primarily employ the solvent method within the transesterification process. After the transesterification reaction, the organic phase solution containing the sucrose fatty acid ester product is extracted through post-treatment. This is followed by high-temperature, reduced-pressure, or atmospheric-pressure distillation to remove the organic solvent (usually n-butanol, isobutanol, or butanone) to obtain the sucrose fatty acid ester product. This method yields products with irregular shapes, inconsistent homogeneity, and a tendency to retain high-boiling-point reaction solvents. Furthermore, prolonged high-temperature distillation can lead to degradation of the sucrose ester product. Therefore, the monoester content of the obtained product is generally close to or lower than that in the organic phase solution state, depending solely on the transesterification reaction. Due to the limitations of the synthesis process, the reaction typically only synthesizes sucrose fatty acid ester products with a monoester content of 20–55%, which is insufficient to meet the needs of specialized fields such as pharmaceuticals, which sometimes require sucrose esters with high monoester content and strong hydrophilicity. To obtain products with higher or lower sucrose monoester content, it is necessary to separate the sucrose fatty acid esters into mono- and diesters. Summary of the Invention

[0008] In order to solve the problems existing in the prior art, the purpose of this invention is to provide a method for preparing sucrose fatty acid ester products that can effectively increase the monoester content, and the sucrose fatty acid ester with high monoester content obtained therefrom.

[0009] One aspect of the present invention provides a method for preparing sucrose fatty acid esters with high monoester content, using crude sucrose fatty acid esters and / or finished sucrose fatty acid esters as crystallization substrates, and using ester solvents or a mixture of ester solvents and alkane solvents as crystallization solvents. The crystallization substrates are dissolved in the crystallization solvent at a predetermined dissolution temperature, and after clearing, the solution is cooled to a predetermined crystallization temperature. After crystallization, the resulting mixture is filtered, washed, and dried to obtain sucrose fatty acid esters with high monoester content.

[0010] In the method for preparing sucrose fatty acid esters with high monoester content provided by the present invention, the crystalline substrate can be a crude sucrose fatty acid ester synthesized by various methods (e.g., a concentrate of the organic phase solution obtained from extraction), a commercially available finished sucrose fatty acid ester, or a sucrose fatty acid ester purified to a certain extent by a purification method. The monoester content in the crude or finished sucrose fatty acid ester substrate is ≥40%.

[0011] Furthermore, the sucrose fatty acid ester is sucrose laurate, sucrose stearate, sucrose palmitate, sucrose myristate, or sucrose decanoate.

[0012] Preferably, the sucrose fatty acid ester is sucrose laurate, sucrose stearate, or sucrose palmitate.

[0013] Furthermore, the ester solvent is selected from one or more of ethyl acetate, isopropyl acetate, n-propyl acetate, butyl acetate, methyl formate, and ethyl formate.

[0014] Preferably, the ester solvent is ethyl acetate or isopropyl acetate.

[0015] Furthermore, the alkane solvent is selected from one or more of n-hexane, n-heptane, cyclohexane, n-octane, and isooctane.

[0016] Preferably, the alkane solvent is n-heptane or n-hexane.

[0017] Furthermore, the mixed solvent of the ester solvent and the alkane solvent is a mixed solvent of ethyl acetate or isopropyl acetate and n-heptane or n-hexane.

[0018] Preferably, the mixed solvent of the ester solvent and the alkane solvent is a mixed solvent of ethyl acetate and n-heptane.

[0019] Further, the weight ratio of crystallization substrate: ester solvent: alkane solvent is 1.0:3.0-15.0:0-2.0; preferably, the weight ratio of crystallization substrate: ester solvent: alkane solvent is 1.0:6.0-10.0:0-2.0; more preferably, the weight ratio of crystallization substrate: ester solvent: alkane solvent is 1.0:6.0-8.0:0-2.0; more preferably, the weight ratio of crystallization substrate: ester solvent: alkane solvent is 1.0:8.0:0-1.0 or 1.0:9.0:0-1.0.

[0020] Furthermore, the predetermined melting temperature is 35–90°C, preferably 40–80°C; more preferably 50–70°C; and even more preferably 60°C.

[0021] Furthermore, the predetermined crystallization temperature is -10 to 30°C, preferably -5 to 15°C; more preferably 0 to 15°C; even more preferably 5 to 10°C; and even more preferably 10°C.

[0022] Optionally, when a high monoester content is required, in addition to single crystallization of the crystallization substrate, multiple crystallizations can be performed. Each crystallization can increase the monoester content by 8–20 wt%, and multiple crystallizations can increase the monoester content to over 95 wt%.

[0023] Another aspect of the present invention provides a sucrose fatty acid ester with high monoester content, which is prepared by the above-described method for preparing a sucrose fatty acid ester with high monoester content, wherein the monoester content of the sucrose fatty acid ester with high monoester content is 65-99 wt%.

[0024] Compared with the prior art, the preparation method provided by the present invention can significantly increase the monoester content in sucrose fatty acid ester products. Each crystallization can increase the monoester content by about 8 to 20 wt%, and the monoester content of the product can be increased to more than 95 wt% by repeated crystallization.

[0025] Compared to traditional separation and purification methods, such as column chromatography, solvent extraction and distillation, this invention provides a more efficient, simple, environmentally friendly, and cost-effective crystallization purification method. Compared to distillation processes, the preparation method provided by this invention avoids the use of expensive and energy-intensive equipment such as distillation columns, molecular thin-film distillation apparatus, or spray drying. It is simple to operate and low in cost, making it more suitable for industrial production. Attached Figure Description

[0026] Figure 1 The high-performance liquid chromatogram of the crude sucrose fatty acid ester in Example 3 is shown.

[0027] Figure 2 The high-performance liquid chromatogram of the sucrose fatty acid ester product obtained in Example 3 is shown.

[0028] Figure 3 The high-performance liquid chromatogram of the sucrose fatty acid ester product obtained in Example 4 is shown. Detailed Implementation

[0029] All features disclosed in this specification, or steps in all methods or processes disclosed herein, may be combined in any way, except for mutually exclusive features and / or steps.

[0030] Any feature disclosed in this specification, unless otherwise stated, may be replaced by other equivalent or similar features. That is, unless otherwise stated, each feature is merely one example of a series of equivalent or similar features.

[0031] The preparation method of the sucrose fatty acid ester with high monoester content of the present invention will be described in detail below.

[0032] According to an exemplary embodiment of the present invention, the method for preparing the sucrose fatty acid ester with high monoester content is as follows: using crude sucrose fatty acid ester and / or finished sucrose fatty acid ester as crystallization substrate, using an ester solvent or a mixed solvent of an ester solvent and an alkane solvent as crystallization solvent, dissolving the crystallization substrate in the crystallization solvent at a predetermined dissolution temperature, and cooling it to a predetermined crystallization temperature after clearing the solution, and filtering, washing and drying the resulting mixture after crystallization to obtain sucrose fatty acid ester with high monoester content.

[0033] The present invention will be further explained below with reference to specific experimental examples, embodiments, and comparative examples.

[0034] Experimental Example 1: Screening of Crystallization Solvent Types and Ratios

[0035] This experiment investigated the effects of different crystallization solvents and their proportions on the monoester content in sucrose fatty acid esters. The specific method was as follows: using 20g of crude sucrose laurate as the substrate (71.6% monoester, 24.8% diester), the quality and yield of the crystallized product were investigated under different solvent systems and weight ratios. The crystallization temperatures were all between 5 and 10℃. The results are shown in Table 1 below.

[0036] Table 1. Experimental data on screening of crystallization solvent ratios

[0037]

[0038]

[0039] Based on the experimental results and data in the table above, as the amount of solvent increases, the monoester content in the product increases, but the yield decreases. On the other hand, adding a certain amount of n-heptane is beneficial to improving the yield and has little effect on the monoester content.

[0040] Experimental Example 2: Screening of Crystallization Temperature

[0041] Using 20g of sucrose laurate (71.6% monoester, 24.8% diester) and 20g of sucrose stearate (66.8% monoester, 29.7% diester) as substrates, and a solvent system of crude product weight: ethyl acetate weight: n-heptane weight of 1:8.0:0.6, the quality and yield of the crystallized products at different crystallization temperatures were investigated. The results are shown in Table 2 below.

[0042] Table 2. Experimental data for screening crystallization temperature

[0043]

[0044]

[0045] The experimental results and data in the table above show that as the crystallization temperature decreases, the yield increases, but the monoester content of the product decreases. When the crystallization temperature is between -10℃ and 25℃, both the yield and monoester content are relatively high. For crude sucrose laurate, especially when the crystallization temperature is between -5℃ and 15℃, both the yield and monoester content are above 81%, indicating excellent quality. For crude sucrose stearate, especially when the crystallization temperature is between 0℃ and 15℃, both the yield and monoester content are around 80%, indicating excellent quality.

[0046] Experimental Example 3: Preparation of Crude Sucrose Fatty Acid Ester

[0047] Add 70.4 g of DMSO (dimethyl sulfoxide) to a 250 ml three-necked flask. While stirring, add 16.0 g of sucrose, 0.38 g of potassium carbonate, and 6.0 g of methyl laurate sequentially. Initiate heating and reduce pressure, maintaining a vacuum < -0.088 MPa and an internal temperature of approximately 90–100 °C for 5 hours. Cool to 20–30 °C. Add 0.57 g of citric acid monohydrate (relative to potassium carbonate) to the system, stir, and distill off approximately 30–40 g of DMSO under reduced pressure. Add 120 g of n-butanol and 200 ml of citric acid aqueous solution (pH = 3–6). After thorough stirring, allow to stand for a period of time, then separate the layers and discard the lower aqueous phase. Add another 200 ml of citric acid aqueous solution (pH = 3–6) to the organic phase, stir thoroughly, allow to stand, and separate the layers, discarding the lower aqueous phase. Concentrate the organic phase under reduced pressure until no obvious liquid distillation occurs, yielding approximately 14 g of crude sucrose laurate, which is a white gel.

[0048] The crude products used in the following examples were prepared using the same method as in Experimental Example 3 or were obtained by purchasing them.

[0049] Example 1: (Crude product content: monoester: 49.86%, diester: 38.45%)

[0050] 100g of crude sucrose laurate and 800g of ethyl acetate were added to a 2L three-necked flask. The mixture was stirred and heated to an internal temperature of 60°C until the system was completely dissolved. The temperature was then lowered to an internal temperature of 10°C, and the mixture was kept at this temperature with stirring to allow crystallization to occur for 2 hours. The mixture was then filtered under vacuum in a dry environment, and the filter cake solid was quickly collected. It was placed in a vacuum drying oven with a vacuum level maintained above -0.090MPa and dried at 45°C for 14 hours. The material was then quickly collected to obtain approximately 82g of sucrose laurate product, with a yield of 82%, which was a white solid powder.

[0051] Product quality: Monoester content 64.65%, Diester content 29.14%.

[0052] Example 2: (Crude product content: monoester: 66.64%, diester: 26.87%)

[0053] Add 100g of crude sucrose laurate and 800g of isopropyl acetate to a 2L three-necked flask. Stir and heat to an internal temperature of 60℃, stirring until the system is completely dissolved. Cool down to an internal temperature of 10℃ and maintain the temperature while stirring to allow crystals to precipitate for 2 hours. Filter under vacuum in a dry environment, quickly collect the filter cake solid, place it in a vacuum drying oven maintaining a vacuum degree above -0.090 MPa, and dry at 45℃ for 14 hours. Quickly collect the material to obtain 80g of sucrose laurate product, with a yield of 80%, as a white solid powder.

[0054] Product quality: monoester content 82.74%, diester content 16.05%.

[0055] Example 3: (Crude product content: monoester: 75.90%, diester: 22.70%, HPLC chromatogram attached) Figure 1 )

[0056] 100g of crude sucrose laurate, 900g of ethyl acetate, and 70g of n-heptane were added to a 2L three-necked flask. The mixture was stirred and heated to an internal temperature of 60°C until the system was completely dissolved. The temperature was then lowered to an internal temperature of 10°C, and the mixture was kept at this temperature with stirring to allow crystallization to occur for 2 hours. The mixture was then filtered under vacuum in a dry environment, and the filter cake solid was quickly collected. It was placed in a vacuum drying oven with a vacuum level maintained above -0.090 MPa and dried at 45°C for 14 hours. The material was then quickly collected to obtain 82g of sucrose laurate product, with a yield of 82%, which was a white solid powder.

[0057] Product quality: Monoester content 88.36%, diester content 11.48%, HPLC chromatogram attached. Figure 2 .

[0058] Example 4: (Crystallization substrate: the product obtained in Example 3)

[0059] Add 50g of the sucrose laurate product obtained in Experiment 3, 400g of ethyl acetate, and 30g of n-heptane to a 2L three-necked flask. Stir and heat to an internal temperature of 60°C until the system is completely dissolved. Cool down to an internal temperature of 10°C and maintain the temperature while stirring to allow crystallization to occur for 2 hours. Filter under vacuum in a dry environment, quickly collect the filter cake solid, place it in a vacuum drying oven maintaining a vacuum degree above -0.090 MPa, and dry at 45°C for 14 hours. Quickly collect the material to obtain 40.1g of sucrose laurate product, with a yield of 80.2%, as a white solid powder.

[0060] Product quality: Monoester content 96.18%, diester content 3.71%, HPLC chromatogram attached. Figure 3 .

[0061] Appendix Figures 1 to 3 The contents of each component in sucrose laurate before and after crystallization are shown in Table 3 below:

[0062] Table 3. Content of each component in sucrose laurate before and after crystallization.

[0063]

[0064] As can be seen from Table 3 above, the monoester content in crude sucrose laurate was increased from 75.9% to 88.4% by the single-crystallization purification method of the present invention, and low hydrophilic components such as polyesters and triesters were removed. After a second crystallization purification, the monoester content was further increased to 96.2%, which is more conducive to the use of subsequent products.

[0065] Example 5: (Crude product content: monoester: 68.98%, diester: 25.76%)

[0066] 8.0 kg of crude sucrose laurate, 72 kg of ethyl acetate, and 5.6 kg of n-heptane were added to a 200 L reactor. The mixture was stirred and heated to an internal temperature of 65 °C until the system was completely dissolved. The temperature was then lowered to an internal temperature of 10 °C, and the mixture was kept at this temperature with stirring to allow crystallization to occur for 2 hours. The mixture was then centrifuged under nitrogen protection until no liquid dripped out. The filter cake solid was quickly collected, spread evenly on a tray, and placed in a square vacuum drying oven at a vacuum level above -0.090 MPa for 20 hours. The product was then collected, yielding 6.5 kg of sucrose laurate, with a yield of 81.2%, as a white solid powder.

[0067] Product quality: monoester content 84.13%, diester content 12.57%.

[0068] Example 6: (Crude product content: monoester: 66.64%, diester: 26.87%)

[0069] 100g of crude sucrose laurate, 900g of isopropyl acetate, and 70g of n-hexane were added to a 2L three-necked flask. The mixture was stirred and heated to an internal temperature of 60°C until the system was completely dissolved. The temperature was then lowered to an internal temperature of 10°C, and the mixture was kept at this temperature with stirring to allow crystallization to occur for 2 hours. The mixture was then filtered under vacuum in a dry environment, and the filter cake solid was quickly collected. It was placed in a vacuum drying oven with a vacuum level maintained above -0.090 MPa and dried at 45°C for 14 hours. The material was then quickly collected to obtain 82g of sucrose laurate product, with a yield of 82%, which was a white solid powder.

[0070] Product quality: Monoester content 81.37%, diester content 16.24%.

[0071] Example 7: (Crude product content: monoester: 52.18%, diester: 38.97%)

[0072] 100g of crude sucrose stearate, 900g of ethyl acetate, and 70g of n-heptane were added to a 2L three-necked flask. The mixture was stirred and heated to an internal temperature of 60°C until the system was completely dissolved. The temperature was then lowered to an internal temperature of 10°C, and the mixture was kept at this temperature with stirring to allow crystallization to occur for 2 hours. The mixture was then filtered under vacuum in a dry environment, and the filter cake solid was quickly collected. It was placed in a vacuum drying oven with a vacuum level maintained above -0.090 MPa and dried at 45°C for 14 hours. The material was then quickly collected to obtain 77g of sucrose laurate product, with a yield of 77%, which was a white solid powder.

[0073] Product quality: Monoester content 69.41%, diester content 23.25%.

[0074] Example 8: (Crude product content: monoester: 55.33%, diester: 37.16%)

[0075] 100g of crude sucrose palmitate, 900g of ethyl acetate, and 70g of n-heptane were added to a 2L three-necked flask. The mixture was stirred and heated to an internal temperature of 60°C until the system was completely dissolved. The temperature was then lowered to an internal temperature of 10°C, and the mixture was kept at this temperature with stirring to allow crystallization to occur for 2 hours. The mixture was then filtered under vacuum in a dry environment, and the filter cake solid was quickly collected. It was placed in a vacuum drying oven with a vacuum level maintained above -0.090 MPa and dried at 45°C for 14 hours. The material was then quickly collected to obtain 81g of sucrose palmitate product, with a yield of 81%, which was a white solid powder.

[0076] Product quality: Monoester content 70.49%, diester content 24.31%.

[0077] Example 9: (Crude product content: monoester: 66.64%, diester: 26.87%)

[0078] Add 10g of crude sucrose laurate, 90g of ethyl acetate, and 7g of n-heptane to a 250ml three-necked flask. Stir and heat to an internal temperature of 40℃, stirring until the system is completely dissolved. Cool to an internal temperature of -10℃ and maintain this temperature while stirring to allow crystallization to occur for 2 hours. Filter under vacuum in a dry environment, quickly collect the filter cake solid, place it in a vacuum drying oven maintaining a vacuum degree above -0.090Mpa, and dry at 45℃ for 14 hours. Quickly collect the material to obtain 8.5g of sucrose laurate product, with a yield of 85%, as a white solid powder.

[0079] Product quality: monoester content 76.83%, diester content 17.93%.

[0080] Example 10: (Crude product content: monoester: 66.64%, diester: 26.87%)

[0081] Add 10g of crude sucrose laurate, 90g of isopropyl acetate, and 7g of n-heptane to a 250ml three-necked flask. Stir and heat to an internal temperature of 80℃, stirring until the system is completely dissolved. Cool down to an internal temperature of 30℃ and maintain this temperature while stirring to allow crystals to precipitate for 2 hours. Filter under vacuum in a dry environment, quickly collect the filter cake solid, place it in a vacuum drying oven maintaining a vacuum degree above -0.090 MPa, and dry at 45℃ for 14 hours. Quickly collect the material to obtain 7.1g of sucrose laurate product, with a yield of 71%, as a white solid powder.

[0082] Product quality: Monoester content 83.20%, diester content 12.19%.

[0083] Comparative Example 1: (Crude product content: monoester: 66.64%, diester: 26.87%)

[0084] 100g of crude sucrose laurate and 900g of acetonitrile were added to a 2L three-necked flask. The mixture was stirred and heated to an internal temperature of 60°C until the system was completely dissolved. The temperature was then lowered to an internal temperature of 10°C, and the mixture was kept at this temperature and stirred for 2 hours to allow crystals to precipitate. The mixture was then filtered under vacuum in a dry environment. The filtration was very slow, and the product was a viscous gel. The product was placed in a vacuum drying oven with a vacuum level above -0.090 MPa and dried at 45°C for 14 hours. The material was then quickly collected to obtain 93g of sucrose laurate, with a yield of 93%, which was a viscous gel.

[0085] The resulting product contained 66.76% monoester and 26.80% diester.

[0086] Comparative Example 2: (Crude product content: monoester: 66.64%, diester: 26.87%)

[0087] 100g of crude sucrose laurate, 900g of acetonitrile, and 70g of n-heptane were added to a 2L three-necked flask. The mixture was stirred and heated to an internal temperature of 60°C until the system was completely dissolved. The temperature was then lowered to an internal temperature of 10°C, and the mixture was kept at this temperature with stirring to allow crystallization to occur for 2 hours. The mixture was then filtered under vacuum in a dry environment. The filtration was very slow, and the product was a viscous gel. The product was placed in a vacuum drying oven with a vacuum level above -0.090 MPa and dried at 45°C for 14 hours. The material was quickly collected to obtain 92.4g of sucrose laurate, with a yield of 92.4%, which was a viscous gel.

[0088] The resulting product contained 66.51% monoester and 26.90% diester.

[0089] Comparative Example 3: (Crude product content: monoester: 66.64%, diester: 26.87%)

[0090] Add 10g of crude sucrose laurate, 90g of ethyl acetate, and 7g of n-heptane to a 250ml three-necked flask. Stir and heat to an internal temperature of 34℃, stirring thoroughly for 3 hours. If the system cannot be completely dissolved, cool to an internal temperature of 10℃ and maintain this temperature while stirring to allow crystals to precipitate for 2 hours. Filter under vacuum in a dry environment, quickly collect the filter cake solid, place it in a vacuum drying oven maintaining a vacuum degree above -0.090 MPa, and dry at 45℃ for 14 hours. Quickly collect the material to obtain 7.8g of sucrose laurate product, with a yield of 78%, as a white solid powder.

[0091] The resulting product contained 68.42% monoester and 24.73% diester.

[0092] Comparative Example 4: (Crude product content: monoester: 66.64%, diester: 26.87%)

[0093] Add 10g of crude sucrose laurate, 90g of ethyl acetate, and 7g of n-heptane to a 250ml three-necked flask. Stir and heat to an internal temperature of 60℃, stirring until the system is completely dissolved. Cool to an internal temperature of -18℃ and maintain this temperature while stirring to allow crystallization to occur for 2 hours. Filter under vacuum in a dry environment, quickly collect the filter cake solid, place it in a vacuum drying oven maintaining a vacuum degree above -0.090Mpa, and dry at 45℃ for 14 hours. Quickly collect the material to obtain 9.5g of sucrose laurate product, with a yield of 95%, as a white solid powder.

[0094] The resulting product contained 67.15% monoester and 26.54% diester.

[0095] In summary, this invention uses crystallization to replace the commonly used industrial distillation method for obtaining sucrose fatty acid ester products, solving the problem of difficult crystallization for this type of product. Compared to distillation, crystallization offers numerous advantages, including shorter cycle time, simpler equipment, lower cost and energy consumption, better control of impurities, and easier process scale-up and industrialization. This invention can significantly increase the monoester content in sucrose fatty acid ester products and can obtain highly hydrophilic sucrose fatty acid ester products using a simple process.

[0096] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A method for preparing a sucrose fatty acid ester with high monoester content, characterized in that, Using crude sucrose fatty acid esters and / or finished sucrose fatty acid esters as crystallization substrates, and a mixed solvent of ester solvents and alkane solvents as crystallization solvents, the crystallization substrates are dissolved in the crystallization solvent at a predetermined dissolution temperature and then cooled to a predetermined crystallization temperature after crystallization. After crystallization, the resulting mixture is filtered, washed, and dried to obtain sucrose fatty acid esters with high monoester content. Crystallization Substrate: The weight ratio of ester solvent to alkane solvent is 1.0:6.0~10.0:0.6~2.0; The predetermined dissolution temperature is 35~90℃; The predetermined crystallization temperature is -10~30℃; The ester solvent is selected from one or more of ethyl acetate, isopropyl acetate, n-propyl acetate, butyl acetate, methyl formate, and ethyl formate; the alkane solvent is selected from one or more of n-hexane, n-heptane, cyclohexane, n-octane, and isooctane.

2. The method for preparing sucrose fatty acid esters with high monoester content according to claim 1, characterized in that, The sucrose fatty acid ester is sucrose laurate, sucrose stearate, sucrose palmitate, sucrose myristate, or sucrose decanoate.

3. The method for preparing sucrose fatty acid esters with high monoester content according to claim 1, characterized in that, The sucrose fatty acid ester is sucrose laurate, sucrose stearate, or sucrose palmitate.

4. The method for preparing sucrose fatty acid esters with high monoester content according to claim 1, characterized in that, The ester solvent is ethyl acetate or isopropyl acetate.

5. The method for preparing sucrose fatty acid esters with high monoester content according to claim 1, characterized in that, The alkane solvent is n-heptane or n-hexane.

6. The method for preparing sucrose fatty acid esters with high monoester content according to any one of claims 1-5, characterized in that, The mixed solvent of the ester solvent and the alkane solvent is a mixed solvent of ethyl acetate or isopropyl acetate and n-heptane or n-hexane.

7. The method for preparing sucrose fatty acid esters with high monoester content according to claim 6, characterized in that, The mixed solvent of the ester solvent and the alkane solvent is a mixed solvent of ethyl acetate and n-heptane.

8. The method for preparing sucrose fatty acid esters with high monoester content according to claim 1, characterized in that, The weight ratio of crystallization substrate to ester solvent to alkane solvent is 1.0:6.0~8.0:0.6~2.

0.

9. The method for preparing sucrose fatty acid esters with high monoester content according to claim 1, characterized in that, The predetermined dissolution temperature is 40~80℃.

10. The method for preparing sucrose fatty acid esters with high monoester content according to claim 1, characterized in that, The predetermined dissolution temperature is 50~70℃.

11. The method for preparing sucrose fatty acid esters with high monoester content according to claim 1, characterized in that, The predetermined crystallization temperature is -5~15℃.

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