A process for the preparation of a highly stable high internal phase emulsion emulsified by monote-tra-decylphosphate disodium

Abstract

The application provides a preparation method of high-stable high internal phase emulsion emulsified by single tetradecyl phosphate disodium (TP2Na), the type of the high internal phase emulsion obtained by the application is oil-in-water (O / W), the volume percentage of the oil phase is not less than 75%, and the highest can reach 92.3%. The stability of the high internal phase emulsion obtained by the application is extremely good, and the highest stable time at 25 DEG C can reach 151 days. The amount of the required surfactant TP2Na of the high internal phase emulsion obtained by the application is low, and the mass percentage in the emulsion is not more than 3.33%. The biodegradable surfactant TP2Na provided by the application has extremely good emulsifying capacity, and can be applied to preparation of high internal phase emulsion of various liquid alkanes, dimethyl silicone oil and oil and fat. The preparation method of the high internal phase emulsion provided by the application is simple, has low equipment requirement, low production cost and no three waste emissions.

Description

Technical Field

[0001] The invention relates to a high internal phase emulsion formed by emulsifying an anionic surfactant, in particular to a highly stable high internal phase emulsion formed by emulsifying disodium monotetradecyl phosphate, and belongs to the technical field of sustainable fine organic chemicals. Background Art

[0002] A high internal phase emulsion is an emulsion in which the internal phase (or dispersed phase) accounts for at least 74.05% by volume. The dispersed internal phase particles in a high internal phase emulsion are irregular polyhedrons, separated from each other by a thin film of continuous liquid. Compared to conventional emulsions, the dense packing of polyhedral particles results in high internal phase emulsions exhibiting significant viscosity, poor fluidity, and even near-involuntary flow. This transforms the internal phase from a flowable liquid into a difficult-to-flow gel, exhibiting excellent plasticity. These emulsions hold significant promise for application in a variety of technical fields, including food processing, cosmetics, porous hollow materials, and biofermentation. Consequently, the design and manufacture of high internal phase emulsions have attracted widespread attention.

[0003] Essentially, high internal phase emulsions belong to the category of emulsion dispersions and are thermodynamically unstable multiphase systems. Similar to conventional emulsions, their construction requires an oil phase, an aqueous phase, and an emulsifier. The oil phase can serve as both the continuous and dispersed phases, while the aqueous phase performs similar functions. However, the two phases complement each other, forming two types: oil-in-water (O / W) and water-in-oil (W / O). Based on existing published technologies, suitable oil phases for constructing high internal phase emulsions include liquid mineral oils and liquid fats. The aqueous phase can be pure water or an aqueous solution containing electrolytes (and / or other water-soluble substances). Emulsifiers include surfactants and their mixtures, organic or inorganic particles, natural or synthetic polymers, and mixtures of two or more of these. Small molecule surfactants were the first to be used as emulsifiers for high internal phase emulsions. Anionic, cationic, nonionic and zwitterionic surfactants are all involved. However, there are many shortcomings in the use of small molecule surfactants as emulsifiers for high internal phase emulsions: first, the amount of surfactant used is generally large, and the mass percentage of surfactant in the resulting high internal phase emulsion is at least 5%, usually around 20% (Chemical Bulletin, 2016, 79(10), 891-896); second, the same small molecule surfactant can mostly only emulsify a certain type of oil phase to form a high internal phase emulsion, and there has been no public report on small molecule surfactants that are suitable for emulsifying multiple types of oil phases (such as polar oils and non-polar oils) to form a high internal phase emulsion; third, there are few small molecule surfactants that are low in irritation, high in safety and environmentally biodegradable. Therefore, it is obviously of great significance and value to seek small molecule surfactants that are used in small amounts, have low irritation, high safety, are environmentally biodegradable, and can emulsify multiple types of oil phases (such as polar oils and non-polar oils) as emulsifiers to form high internal phase emulsions.

[0004] In order to solve the technical defects of preparing high internal phase emulsions using small molecule surfactants as emulsifiers, the present invention proposes a method for preparing a highly stable high internal phase emulsion emulsified by disodium monotetradecyl phosphate (TP2Na). Using the small molecule anionic surfactant TP2Na as an emulsifier, a variety of liquid oils are efficiently emulsified. By a simple preparation method, an O / W type high internal phase emulsion with low emulsifier dosage, high internal phase volume percentage, good gel performance and strong stability is obtained. The structural formula of the TP2Na used is shown in the figure below:

[0005] . Summary of the Invention

[0006] The purpose of the present invention is to address the technical defects of the current preparation of high internal phase emulsions using small molecule surfactants as emulsifiers and to provide a method for preparing a highly stable high internal phase emulsion emulsified by disodium monotetradecyl phosphate (TP2Na).

[0007] A method for preparing a highly stable, high internal phase emulsion emulsified with disodium monotetradecyl phosphate (TP2Na) is disclosed. The method uses the small molecule anionic surfactant TP2Na as an emulsifier to efficiently emulsify various liquid oils. The method provides an O / W type high internal phase emulsion with low emulsifier dosage, high internal phase volume percentage, good gelation properties, and strong stability. The specific steps are as follows:

[0008] S1: neutralizing a mixture of monotetradecyl phosphate (TP2H) and water with sodium hydroxide and adjusting the pH of the aqueous solution to not less than 9.3, and using the resultant as the aqueous phase to prepare a high internal phase emulsion;

[0009] S2: The aqueous phase obtained in S1 is mixed with liquid oil so that the volume percentage of the oil in the final emulsion is not less than 75%, and then homogenized to obtain a high internal phase emulsion.

[0010] Furthermore, neutralizing the mixture of TP2H and water with sodium hydroxide in S1 refers to conducting the reaction at 25 degrees Celsius according to a molar ratio of TP2H and sodium hydroxide of 1:2, and the mass percentage of TP2H in the mixture of TP2H and water is 0.56% to 2.9%.

[0011] Furthermore, in said S1, the pH of the aqueous solution is adjusted to not less than 9.3, which refers to the pH value measured at 25 degrees Celsius. The pH range is preferably 9.3 to 14.0, and the most preferred pH range is 11 to 12. The mass percentage of TP2Na in the obtained TP2Na aqueous solution ranges from 0.64 to 3.33%.

[0012] Furthermore, the liquid oil in S2 refers to any one of liquid mineral oil, liquid fat and dimethyl silicone oil. Liquid mineral oil refers to one of normal saturated alkanes with a total carbon atom count in the range of 7 to 16 in the molecular structure and a liquid mixture of two or more thereof. Liquid fat refers to any one of jojoba oil, isopropyl myristate, sunflower oil, dimethyl silicone oil, soybean oil, rapeseed oil, peanut oil, tea seed oil and sesame oil.

[0013] Furthermore, in S2, the aqueous phase obtained in S1 is mixed with liquid oil so that the volume percentage of the oil in the final emulsion is not less than 75%, and the volume percentage of the oil in the final emulsion can reach up to 92.3%.

[0014] Furthermore, the high internal phase emulsion prepared by homogenization in S2 refers to homogenization at room temperature using a high-speed homogenizer at a speed of 1000 rpm for 1 minute. The high internal phase emulsion refers to an O / W emulsion in which the volume percentage of the oil phase is not less than 75% (up to 92.3%).

[0015] A method for preparing a highly stable, high-internal-phase emulsion emulsified by TP2Na, wherein the efficient emulsification of multiple liquid oils means that any of the aqueous phases obtained in S1 can be used to emulsify any of the oil phases described in the present invention, including liquid mineral oil, liquid grease, and dimethyl silicone oil, to form an O / W-type high-internal-phase emulsion. That is, the type of oil phase can be arbitrarily changed within the range of oil phases described in the present invention without changing the pH and TP2Na concentration of any aqueous phase obtained in S1, and an O / W-type high-internal-phase emulsion can be obtained according to S2 of the present invention.

[0016] The method of the present invention has the following advantages over the prior art:

[0017] 1. The small molecule anionic surfactant TP2Na provided by the present invention has good water solubility, high surface activity, and excellent emulsification and solubilization capabilities. Given that TP2Na's molecular structure contains a divalent anionic hydrophilic group, which is different from the monovalent anionic hydrophilic group in the molecular structure of conventional small molecule anionic surfactants, the excellent performance exhibited by the small molecule anionic surfactant TP2Na provided by the present invention has broken the traditional understanding of the molecular structure characteristics of conventional small molecule anionic surfactants.

[0018] 2. The method for preparing a high internal phase emulsion provided by the present invention only requires a small molecule surfactant as an emulsifier, without the need to add other types of surfactants, synthetic or natural polymers, alcohols and sugars.

[0019] 3. The method for preparing the high internal phase emulsion provided by the present invention requires a low amount of emulsifier (the mass percentage of TP2Na in the emulsion does not exceed 3.33%), and the TP2Na used can be degraded by environmental microorganisms or hydrolyzed by enzymes.

[0020] 4. The method for preparing a high internal phase emulsion provided by the present invention can effectively emulsify a variety of liquid mineral oils, liquid greases and liquid dimethyl silicone oils to obtain an O / W type high internal phase emulsion without changing the concentration and pH of TP2Na.

[0021] 5. The method for preparing a high internal phase emulsion provided by the present invention can efficiently and simply obtain a high internal phase emulsion through a one-step high-speed homogenization emulsification, without the need to adopt other measures or steps such as shearing, ultrasound, high pressure, secondary or multiple emulsification, concentration, separation of excess water phase or oil phase, etc. The production process is simple, the equipment requirements are low, the production cost is low, the energy consumption is low, and there is no discharge of three wastes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of monotetradecyl phosphate TP2H obtained in Example 1 of the present invention.

[0023] Figure 2 This is the mass spectrum of monotetradecyl phosphate TP2H obtained in Example 1 of the present invention.

[0024] Figure 3 This is the acid-base titration curve of monotetradecyl phosphate TP2H obtained in Example 2 of the present invention.

[0025] Figure 4 This is a surface (interfacial) tension curve of monotetradecyl phosphate disodium TP2Na obtained in Example 2 of the present invention.

[0026] Figure 5 This is a rendering of the high internal phase emulsion obtained in Example 3 of the present invention. DETAILED DESCRIPTION

[0027] The following specific examples further illustrate the preparation method and effects of the monotetradecyl phosphate (TP2H), monotetradecyl phosphate disodium salt (TP2Na) aqueous solution, and the highly stable high internal phase emulsion emulsified by TP2Na provided by the present invention.

[0028] Example 1: Monotetradecyl phosphate (TP2H)

[0029] 129.1 g of pyrophosphoric acid was added to a 1000 mL round-bottom flask, followed by 70.2 g of tetradecanol and 800 mL of anhydrous benzene. After continuous stirring at 25 degrees Celsius using mechanical stirring for 48 hours, 100 mL of deionized water was added and heated to reflux, and the reaction was continued for 4 hours to terminate the reaction. After cooling, the reaction mass was added to 500 mL of ether and mixed thoroughly, and then allowed to stand for stratification. After separating the aqueous phase, the organic phase was washed three times with 250 mL of deionized water. The organic phase was slowly dripped into an aqueous solution containing excess sodium hydroxide, and an appropriate amount of ether was added midway to reduce the viscosity, maintaining the aqueous phase pH around 13.5. After separating the organic phase, the aqueous phase pH was adjusted to about 0.5 with concentrated hydrochloric acid, and then about 500 mL of ether was added for extraction. After separating the aqueous phase, the organic phase was washed 2 to 3 times with water at a pH of 0.5. Finally, the organic phase was transferred to a round-bottom flask and rotary evaporated to obtain a light yellow solid, which was then dried in a vacuum drying oven at 30 degrees Celsius to obtain a light yellow crude product. Finally, the crude product was recrystallized three times with n-hexane. After removing the n-hexane, the final product TP2H (white shiny solid) was obtained with a yield of 84.1%. The results were analyzed by hydrogen nuclear magnetic resonance ( Figure 1 ) and soft ionization electrospray mass spectrometry ( Figure 2 ) to verify its molecular structure.

[0030] Depend on Figure 1(Using deuterated chloroform as solvent), we can see that the H signal of the methyl group is near 0.88ppm, the H signal of the 11 methylene groups in the hydrophobic chain is near 1.26ppm, the H signal of the methylene group directly connected to the phosphate group is near 1.69ppm and 4.06ppm, the H signal of the methylene group adjacent to the methylene group connected to the phosphate group is near 1.69ppm, and the signal of the two hydroxyl groups on the phosphate group is at 6.63ppm. The area integral ratio of the above H signals is 3:21.7:2:2:2.3, which is very close to the theoretical value of the TP2H molecular structure. The theoretical calculated value of the relative molecular mass M of TP2H is 294.3. Figure 2 (Chloroform as solvent, positive ion mode) It can be seen that the signals at m / z 295.2, 589.4, 883.6, 1177.8 and 1472.0 in the figure correspond to [M+H] + 、[2M+H] + , [3M+H] + 、[4M+H] + and [5M+H] + The positive ion species were detected, confirming that the obtained substance was TP2H. The purity of the obtained TP2H was about 98.9% by phosphomolybdenum blue ultraviolet spectrophotometry.

[0031] The TP2H used in the subsequent examples of the present invention was carried out using the method and process described in Example 1.

[0032] Example 2: Monotetradecyl phosphate disodium aqueous solution (TP2Na)

[0033] Since TP2H contains two neutralizable acidic hydroxyl groups ( Figure 1 ), in order to ensure the acquisition of TP2Na, it is necessary to first determine the pKa value of TP2H.

[0034] Method for determining the pKa value of TP2H: Prepare a 0.005 mol / L TP2H solution with a 3:1 volume ratio of ethanol and water, and then prepare a 0.01 mol / L sodium hydroxide solution with a 3:1 volume ratio of ethanol and water. At 25 degrees Celsius, titrate the TP2H solution with the sodium hydroxide solution. Monitor the pH value of the mixed solution with a glass pH electrode throughout the titration process. Record the titrated volume of the sodium hydroxide solution and the pH value of the corresponding solution, and draw a titration curve ( Figure 3 ),Depend on Figure 3Derivative processing of the resulting titration curve revealed that the pKa1 and pKa2 of TP2H were approximately 4.1 and 8.5, respectively. This indicates that after TP2H and sodium hydroxide are fully neutralized in water and the resulting aqueous solution is adjusted to a pH of 11.5, the molar ratio of TP2Na in the aqueous solution is approximately 99.9%. Visual observation revealed that the Krafft temperature of TP2Na was approximately 0.3 degrees Celsius, indicating good water solubility. The surface tension (γ) curve method and the interfacial tension (IFT) curve method ( Figure 4 ), the critical micelle concentration of TP2Na was found to be approximately 1.9×10 -2 mol / L, it can reduce the interfacial tension between petroleum ether and water with a boiling range of 90-120 degrees Celsius to 11.4 mN / m. It can be seen that the surface and interfacial activity of TP2Na are relatively high.

[0035] The emulsifier, i.e., TP2Na, and the aqueous phase, i.e., the TP2Na aqueous solution, used in the subsequent examples of the present invention were prepared according to the method described in Example 2, i.e., the reaction was carried out at 25 degrees Celsius according to a molar ratio of TP2H and sodium hydroxide of 1:2, and the pH value of the resulting TP2Na aqueous solution was adjusted with sodium hydroxide to be in the range of 9.3 to 14.0. The mass percentage of TP2H in the mixture of TP2H and water was in the range of 0.56% to 2.9%, and the mass percentage of TP2Na in the resulting TP2Na aqueous solution was in the range of 0.64% to 3.33%.

[0036] Example 3: A series of high internal phase emulsions with alkanes as the oil phase

[0037] In this example, the TP2Na aqueous solution described in Example 2 was used as the aqueous phase. The pH of the aqueous phase was within the range of 9.0 to 14.0, and the mass percentage of TP2Na in the aqueous phase was within the range of 0.64 to 3.33% (specific data points are listed in Table 1). n-dodecane (C12) was used as the oil phase, and the mixture was mixed with the aqueous phase at oil phase volume fractions within the range of 75% to 95% (specific data points are listed in Table 1). High internal phase emulsions were prepared at room temperature, a rotation speed of 1000 rpm, and a homogenization time of 1 minute. The codes of the resulting high internal phase emulsions are listed in Table 1. The stability of the emulsions was determined by observing the presence of an oil phase at 25 degrees Celsius. The morphology of the emulsion droplets was observed using an ultra-depth-of-field microscope. The type of the emulsion was determined using the continuous phase dilution method. The viscosity of the emulsion was determined by inverting the container.

[0038] Table 1 Composition and effects of a series of high internal phase emulsions with alkanes as oil phase

[0039]

[0040] The results in Table 1 show that all systems can form high internal phase emulsions. Verified by the continuous phase dilution method, the resulting high internal phase emulsions, HIPE1 to HIPE16, are all O / W emulsions. The stability of each high internal phase emulsion varies depending on the pH and oil-water volume ratio. For high internal phase emulsions with an oil phase volume fraction of 85% and a TP2Na content of 2.0% in the aqueous phase (HIPE1 to HIPE9 in Table 1), they are all stable for over 7 days within the pH range of 9.3 to 14, and for over 120 days within the pH range of 11 to 12. Therefore, the optimal pH range is 9.3 to 14.0, and the most preferred pH range is 11 to 12.

[0041] The data for HIPE6 and HIPE10-16 in Table 1 show that when the fixed aqueous phase TP2Na content is 2.0% and the pH is 11.5, the stability time of the high internal phase emulsion changes with the oil phase volume fraction. When the oil phase volume fraction exceeds 92%, the stability time of the high internal phase emulsions (HIPE14-HIPE16) does not exceed 7 days. Fine-tuning the oil phase volume fraction within the range of 92%-93% reveals that the high internal phase emulsions obtained with an oil phase volume fraction as high as 92.3% can maintain stability for 7 days or longer. Therefore, using "7 days of stability at 25°C" as the criterion for a "stable high internal phase emulsion," the oil phase volume fraction range for highly stable high internal phase emulsions stabilized by TP2Na and containing C12 as the oil phase is 75%-92.3%.

[0042] By inverting the container, it is observed that the viscosity of the high internal phase emulsion is relatively significant, and it can resist the influence of the gravity field and independently support its own weight ( Figure 5 A, HIPE12); The oil phase droplets of the high internal phase emulsion are polyhedral structures as observed by ultra-depth microscopy ( Figure 5 B, HIPE12), are tightly packed with each other and separated by a thin layer of liquid film of the aqueous phase. It is precisely because of the tight packing of the polyhedral structure droplets that they have obvious viscosity.

[0043] Based on the results in Table 1, the effect of the TP2Na content in the aqueous phase on high internal phase emulsions was further investigated. The volume percentage of C12 was fixed at 85% and the pH was 11.5. The results showed that when the mass percentage of TP2Na in the aqueous TP2Na solution was less than 0.64%, the resulting emulsion was stable for less than 7 days and had sufficient viscosity to support its own weight. When the mass percentage of TP2Na in the aqueous TP2Na solution was greater than 3.33%, the resulting emulsion was stable for more than 7 days but had insufficient viscosity to support its own weight. Therefore, the preferred range of the mass percentage of TP2Na in the aqueous phase of high internal phase emulsions is 0.64–3.33%.

[0044] Based on the research on high internal phase emulsions with C12 as the oil phase, further investigation was conducted on the use of one or more mixtures of n-heptane (C7), n-decane (C10), n-tetradecane (C14), n-hexadecane (C16), and petroleum ether with a boiling range of 60-90°C (C69) and 90-120°C (C912), respectively, as the oil phase. The mixtures were prepared under the conditions of an oil phase volume fraction in the range of 75%-92.3%, a TP2Na content in the aqueous phase in the range of 0.64-3.33%, and an aqueous phase pH of 11.5 (specific data points are listed in Table 2). High internal phase emulsions were prepared at room temperature, a rotation speed of 1000 rpm, and a homogenization time of 1 minute. The codes of the obtained high internal phase emulsions are listed in Table 2.

[0045] Table 2 Composition and effects of a series of high internal phase emulsions with alkanes as the oil phase (water phase pH 11.5)

[0046]

[0047] As shown in Table 2, the stability time of samples HIPE17 to HIPE38 all exceeded two months, demonstrating good stability. This indicates that the use of TP2Na as an emulsifier to prepare high internal phase emulsions with liquid saturated alkanes as the oil phase exhibits good universality. More importantly, without changing the type of emulsifier, the pH of the aqueous phase, the emulsifier concentration, and the volume ratio of the oil and water phases, high internal phase emulsions with good stability can be obtained by changing the type of oil phase.

[0048] Furthermore, when the aqueous phase pH was 11.5, the mass percentage of TP2Na in the aqueous phase was 2.0%, and C12 was the oil phase, high internal phase emulsions with oil phase volume fractions of 75%, 80%, 85%, and 90% were centrifuged at 12,000 rpm for 5 minutes without any demulsification, demonstrating the good stability of the resulting high internal phase emulsion. A high internal phase emulsion with a 90% oil phase volume fraction was placed at 4, 25, and 45 degrees Celsius for 10 hours before returning to room temperature and observation, and no visible demulsification occurred, further demonstrating the good stability of the resulting high internal phase emulsion.

[0049] Example 4: Series of high internal phase emulsions with dimethyl silicone oil as the oil phase

[0050] In this example, the TP2Na aqueous solution described in Example 2 was used as the aqueous phase, the pH value of the aqueous phase was in the range of 9.3 to 12.0, the mass percentage of TP2Na in the aqueous phase was in the range of 0.64 to 3.33%, and dimethyl silicone oil was used as the oil phase. The oil phase volume fraction was in the range of 75% to 92.3% and was mixed with the aqueous phase. A high internal phase emulsion was prepared at room temperature, a rotation speed of 1000 rpm, and a homogenization time of 1 minute.

[0051] The results showed that all systems with dimethicone as the oil phase formed high internal phase emulsions. Verified by the continuous phase dilution method, the resulting high internal phase emulsions were all O / W emulsions. They were stable for over 7 days within the pH range of 9.3-12.0, and for over 80 days within the pH range of 11-12. Therefore, for high internal phase emulsions with dimethicone as the oil phase, the optimal pH range for the aqueous phase is 9.3-12.0, with the most preferred pH range being 11-12. Using the criterion of "stable high internal phase emulsions" (stable for 7 days at 25 degrees Celsius) as the evaluation criteria, the oil phase volume fraction in TP2Na-stabilized high stable high internal phase emulsions with dimethicone as the oil phase ranged from 75% to 90%. When the aqueous phase pH was 11.5 and the mass percentage of TP2Na in the aqueous phase was 2.0%, high internal phase emulsions containing 75%, 80%, 85%, and 90% dimethyl silicone oil by volume were centrifuged at 12,000 rpm for 5 minutes. None of the emulsions showed any demulsification, demonstrating the good stability of the resulting high internal phase emulsions. A high internal phase emulsion containing 90% oil by volume was placed at 4, 25, and 45 degrees Celsius for 10 hours and then returned to room temperature for observation. No visible demulsification was observed, further demonstrating the good stability of the resulting high internal phase emulsion. All high internal phase emulsions containing 75% to 90% dimethyl silicone oil by volume and an aqueous phase pH of 11.5 exhibited viscosities sufficient to support their own weight in an inverted container.

[0052] Example 5: A series of high internal phase emulsions with jojoba oil as the oil phase

[0053] In this example, the TP2Na aqueous solution with a fixed pH value of 11.5 described in Example 2 was used as the aqueous phase, and the mass percentage of TP2Na in the aqueous phase ranged from 0.64% to 3.33%. Jojoba oil was used as the oil phase, and the oil phase volume fraction was mixed with the aqueous phase in a range of 75% to 92.3%. A high internal phase emulsion was prepared at room temperature, a rotation speed of 1000 rpm, and a homogenization time of 1 minute.

[0054] The results showed that all systems with jojoba oil as the oil phase formed high internal phase emulsions. Verification by the continuous phase dilution method confirmed that the resulting high internal phase emulsions were all O / W emulsions. All of the resulting high internal phase emulsions were stable for over 87 days, with those containing 75% to 91% jojoba oil by volume exhibiting stability exceeding 96 days. High internal phase emulsions containing 75%, 80%, 85%, and 90% jojoba oil by volume showed no demulsification after centrifugation at 12,000 rpm for 6 minutes, demonstrating the good stability of the resulting high internal phase emulsions. A high internal phase emulsion containing 90% oil by volume was placed at 4, 25, and 45 degrees Celsius for 11.6 hours before returning to room temperature and observing the emulsions. This further demonstrates the good stability of the resulting high internal phase emulsions. All high internal phase emulsions containing 80% to 90% dimethicone by volume have a viscosity that can support their own weight in an inverted container.

[0055] Example 6: A series of high internal phase emulsions with isopropyl myristate as the oil phase

[0056] In this example, the aqueous solution with a fixed pH of 11.5 and a TP2Na content of 2.0% described in Example 2 was used as the aqueous phase, and isopropyl myristate was used as the oil phase. The oil phase volume fractions were mixed with the aqueous phase at a range of 75% to 92%. A high internal phase emulsion was prepared at room temperature, a rotation speed of 1000 rpm, and a homogenization time of 1 minute.

[0057] The results showed that all systems with myristyl isopropyl ester as the oil phase formed high internal phase emulsions. Verification by the continuous phase dilution method confirmed that the resulting high internal phase emulsions were all O / W emulsions. All of the resulting high internal phase emulsions were stable for over 72 days, with those containing 75% to 90% myristyl isopropyl ester by volume exhibiting stability exceeding 93 days. High internal phase emulsions containing 75%, 80%, 85%, and 90% myristyl isopropyl ester by volume exhibited no demulsification after centrifugation at 12,000 rpm for 7.2 minutes, demonstrating the good stability of the resulting high internal phase emulsions. A high internal phase emulsion containing 90% oil phase by volume was placed at 4, 25, and 45 degrees Celsius for 12.6 hours and then returned to room temperature for observation, revealing no visible demulsification, further demonstrating the good stability of the resulting high internal phase emulsions. All high internal phase emulsions with a volume percentage of 80% to 90% isopropyl myristate have a viscosity that allows them to support their own weight in an inverted container.

[0058] Example 7: Series of high internal phase emulsions with liquid vegetable oil as oil phase

[0059] In this example, the aqueous solution with a fixed pH of 11.5 and a TP2Na content of 2.0% described in Example 2 was used as the aqueous phase, and sunflower oil, soybean oil, rapeseed oil, peanut oil, tea seed oil, and sesame oil were used as oil phases. The oil phases were mixed with the aqueous phase at a ratio of 90% by volume, and a high internal phase emulsion was prepared at room temperature, a rotation speed of 1000 rpm, and a homogenization time of 1 minute.

[0060] The results show that all the obtained systems in this embodiment can form high internal phase emulsions; verified by the continuous phase dilution method, the obtained high internal phase emulsions are all O / W type emulsions; the obtained high internal phase emulsions can be stable for more than 79 days, among which the high internal phase emulsions with tea seed oil, rapeseed oil and sesame oil as the oil phase have a stability time of more than 101 days. All the high internal phase emulsions in this embodiment were centrifuged at 12,000 rpm for 5.2 minutes, and the emulsions did not show any demulsification phenomenon, indicating that the obtained high internal phase emulsions have good stability. All the high internal phase emulsions in this embodiment were placed at 4 degrees Celsius, 25 degrees Celsius and 45 degrees Celsius for 10.6 hours and then returned to room temperature for observation. No visible demulsification phenomenon occurred, further indicating that the obtained high internal phase emulsions have good stability. The viscosity of all the high internal phase emulsions in this embodiment can support their own weight in an inverted container.

[0061] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. After the disclosure of the present invention, any person skilled in the art can easily change or replace the components, and all technical improvements that do not depart from the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a highly stable high internal phase emulsion emulsified with disodium monotetradecyl phosphate, characterized in that: The specific steps are as follows: S1: neutralizing a mixture of monotetradecyl phosphate and water with sodium hydroxide and adjusting the pH of the aqueous solution to not less than 9.3 to obtain an aqueous solution of disodium monotetradecyl phosphate, which is used as the aqueous phase; S2: The aqueous phase obtained in the above step S1 is mixed with liquid oil according to the volume percentage of the oil in the final emulsion of 75% to 92.3%, and then a high internal phase emulsion is prepared by a homogenization step.

2. The preparation method according to claim 1, characterized in that In step S1, monotetradecyl phosphate and water are reacted at 25 degrees Celsius in a molar ratio of monotetradecyl phosphate to sodium hydroxide of 1:2 to obtain a surfactant, disodium monotetradecyl phosphate. The mass percentage of monotetradecyl phosphate in the mixture of monotetradecyl phosphate and water is in the range of 0.56% to 2.9%.

3. The preparation method according to claim 1, characterized in that The pH of the aqueous solution in step S1 is 9.3-14.

0.

4. The preparation method according to claim 3, characterized in that The pH value of the aqueous solution in step S1 is in the range of 11 to 12.

5. The preparation method according to claim 1, characterized in that In step S1, the mass percentage of disodium monotetradecyl phosphate in the disodium monotetradecyl phosphate aqueous solution is in the range of 0.64-3.33%.

6. The preparation method according to claim 1, characterized in that The liquid oil in step S2 refers to any one of liquid mineral oil, liquid grease and dimethyl silicone oil.

7. The preparation method according to claim 6, characterized in that The liquid mineral oil refers to one of normal saturated alkanes with a total carbon atom count in the range of 7 to 16 in the molecular structure, and a liquid mixture of two or more of the normal saturated alkanes.

8. The preparation method according to claim 6, characterized in that The liquid oil is any one of jojoba oil, isopropyl myristate, sunflower oil, dimethyl silicone oil, soybean oil, rapeseed oil, peanut oil, tea seed oil and sesame oil.

9. The preparation method according to claim 1, characterized in that The homogenization step in step S2 is to use a high-speed homogenizer to homogenize at room temperature at a speed of 1000 rpm for 1 minute.

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