Preparation method of polyglycerol-3 diisostearate

Abstract

The invention relates to the technical field of fine chemical engineering, and discloses a preparation method of polyglycerol-3 diisostearate. The preparation method comprises the following steps: carrying out degassing treatment on tripolyglycerol, replacing air, heating to 195-220 DEG C in a protective atmosphere, starting to dropwise add a mixed solution of a catalyst and isostearic acid into the degassed tripolyglycerol at 195 DEG C, and stirring and reacting for 3-5 hours at the speed of 150-220 r / min after dropwise adding is ended; after the reaction is finished, closing the protective atmosphere, reducing the pressure to-0.05 to-0.08 MPa, and continuing the reaction for 1-3 hours; then recovering the pressure, introducing a protective atmosphere, cooling to 60-70 DEG C, closing the protective atmosphere, reducing the pressure to-0.05 to-0.08 MPa, and standing for 3-5 hours to obtain a crude product of polyglycerol-3-diisostearate; the crude product is subjected to alkali refining, water washing, concentration and purification, and the polyglycerol-3 diisostearate is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemicals, and in particular to a method for preparing polyglycerol-3 diisostearate. Background Art

[0002] Polyglyceryl triisostearate is made by esterifying triglycerol with isostearic acid. The appearance of polyglyceryl triisostearate varies depending on the number of isostearic acids combined. It is usually a light yellow to yellow viscous liquid. Triglyceryl isostearate has both hydrophilic and lipophilic properties, and has multiple properties such as good emulsification, dispersion, wetting, stability, and foaming. It can be decomposed during the human body's metabolism, thereby participating in metabolism and being used by the human body. It is highly safe and is a non-ionic surfactant and emulsifier commonly used in cosmetics and personal care products.

[0003] Polyglyceryl triisostearate is widely used in cosmetic preparation as a multifunctional cosmetic ingredient due to its emulsifying, moisturizing, smooth, heat-resistant, water-resistant properties, ability to improve product texture and performance, and ability to provide additional skin care effects. Its performance is specifically reflected in the following aspects: ① It has excellent emulsifying properties and stability, can combine water and oil to form a stable emulsion or emulsified system, and is an ideal ingredient for many milky products such as lotions, face creams, and sunscreens; ② It can enhance the smoothness and lubricity of the product, making it easier to apply and push; ③ It can form a protective film, effectively reduce the loss of skin moisture, keep the skin moist and soft, and has excellent moisturizing properties. It is often added to moisturizing products such as face creams, body lotions, and lipsticks to provide additional moisturizing effects; ④ It has good temperature and water resistance, can remain stable under high temperature conditions, can maintain emulsification properties in water, and is not easy to separate or fail, so it has become an important component of many waterproof cosmetics and long-lasting products.

[0004] The currently known synthesis methods of triglycerol isostearate mainly include chemical method and enzyme catalysis method. Among them, the enzyme catalysis synthesis technology is still in the laboratory research stage due to its high cost and immature technology, and has not yet been promoted to industrialization; the industrial synthesis of triglycerol isostearate is to directly esterify triglycerol with isostearic acid, which requires reasonable selection of catalysts and precise control of reaction conditions. Commonly used catalysts are inorganic base catalysts, mainly potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, etc. The specific preparation method is: fully mix polyglycerol, inorganic base and isostearic acid, react at 220-260℃ for 2-3h, and use the acid value close to zero to judge the reaction end point. The preparation method has the following problems: ① At the reaction temperature, the inorganic base and polyglycerol will polymerize to form a highly polymerized polyglycerol, which will then react with isostearic acid. The resulting product usually has unpleasant color, odor, etc., which limits the application of polyglycerol isostearate in the fields of food, personal care products, etc.; ② The catalyst selectivity is low, and a cyclization reaction is easily caused after the raw materials and the catalyst are mixed, making it difficult to obtain valuable chain esters, thereby affecting the emulsification properties of tripolyglycerol isostearate. Summary of the invention

[0005] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, one of the purposes of the present invention is to provide a method for preparing polyglyceryl-3 diisostearate; another purpose of the present invention is to provide the application of polyglyceryl-3 diisostearate prepared by the preparation method.

[0006] The basic principle of the present invention is described as follows:

[0007] The esterification reaction is a reversible reaction, and byproducts represented by water will be generated during the process. Water will affect the balance of the reaction. Therefore, after the catalyst, isostearic acid and triglycerol are mixed, the present invention strictly controls the pressure of the reaction process and the temperature of different reaction stages, specifically: in step S1, reacting at 195-220°C for 3-h can allow triglycerol and isostearic acid to react quickly to generate monoesters and diesters; reducing the pressure to -0.05-0.08MPa for 1-3h can further promote the conversion of monoesters into diesters; standing at 60-70°C and -0.05-0.08MPa for 3-5h can eliminate low-boiling byproducts generated during the reaction, thereby avoiding the product polyglycerol-3 diisostearate having a strong odor and high chroma.

[0008] The first aspect of the present invention provides a method for preparing polyglyceryl-3 diisostearate, comprising the following steps:

[0009] S1, after degassing the triglycerol, replace the air, heat to 195-220°C under a protective atmosphere, and start to drip a mixed solution of a catalyst and isostearic acid into the degassed triglycerol at 195°C, and stir the reaction at a rate of 150-220r / min for 3-5h after the dripping is completed; after the completion, close the protective atmosphere and reduce the pressure to -0.05-0.08MPa, and continue the reaction for 1-3h; then restore the pressure, introduce the protective atmosphere, and cool to 60-70°C, then close the protective atmosphere and reduce the pressure to -0.05-0.08MPa, and let it stand for 3-5h to obtain a crude product of polyglycerol-3 diisostearate;

[0010] S2, the crude product of polyglycerol-3 diisostearate is smelted with alkali and washed with water to obtain a polyglycerol-3 diisostearate solution;

[0011] S3. The polyglyceryl-3 diisostearate solution is concentrated and purified to obtain the polyglyceryl-3 diisostearate.

[0012] Preferably, in step S1, the process parameters of the triglycerol degassing treatment include at least one of the following parameters:

[0013] 1) The degassing pressure is -0.05 to -0.08 MPa;

[0014] 2) The degassing temperature is 70-90°C;

[0015] 3) The degassing time is 10 to 20 minutes;

[0016] 4) The stirring rate of the degassing is 80-100 r / min.

[0017] Further preferably, in step S1, the process parameters of the triglycerol degassing treatment include at least one of the following parameters:

[0018] 1) The degassing pressure is -0.05 to -0.08 MPa;

[0019] 2) The degassing temperature is 80-90°C;

[0020] 3) The degassing time is 15 to 20 minutes;

[0021] 4) The stirring rate of the degassing is 85-95 r / min.

[0022] Specifically, degassing can remove volatile gases such as air moisture carried in the raw materials and improve the esterification rate.

[0023] Preferably, in step S1, the mixed solution of the catalyst and isostearic acid is prepared by a method comprising the following steps:

[0024] The catalyst is heated and dissolved in isostearic acid to obtain the mixed solution.

[0025] Preferably, the temperature for heating and dissolving is 70-90°C; more preferably, the temperature for heating and dissolving is 70-80°C.

[0026] Preferably, in step S1, the droplet speed of the mixed solution is 15 to 25 mL / min; more preferably, the droplet speed of the mixed solution is 18 to 22 mL / min.

[0027] Preferably, the molar ratio of the triglycerol to isostearic acid is 1:(1.5-3); further preferably, the molar ratio of the triglycerol to isostearic acid is 1:(1.8-2.5); further preferably, the molar ratio of the triglycerol to isostearic acid is 1:(2-2.2).

[0028] Preferably, the amount of the catalyst added is 0.1-1% of the total mass of the triglycerol and isostearic acid; further preferably, the amount of the catalyst added is 0.3-0.7% of the total mass of the triglycerol and isostearic acid.

[0029] Preferably, the catalyst is selected from at least one of alkali metal hydroxides, alkali metal carbonates and alkali metal alkoxides; further preferably, the catalyst is selected from at least one of potassium hydroxide, sodium hydroxide, sodium carbonate, lithium carbonate and sodium methoxide.

[0030] Preferably, in step S2, the process parameters of the alkali refining include at least one of the following parameters:

[0031] 1) The alkali refining temperature is 60-100°C;

[0032] 2) the alkali refining time is 20 to 60 minutes;

[0033] 3) The stirring rate of the alkali refining is 100-600 r / min;

[0034] 4) adding alkali during alkali refining; the alkali is selected from alkali metal hydroxides;

[0035] 5) The amount of the alkali used is 0.1-0.8% of the mass of the crude product of polyglycerol-3 diisostearate.

[0036] Further preferably, in step S2, the process parameters of the alkali refining include at least one of the following parameters:

[0037] 1) The alkali refining temperature is 70-80°C;

[0038] 2) The alkali refining time is 30 to 40 minutes;

[0039] 3) The stirring rate of the alkali refining is 200-300 r / min;

[0040] 4) adding alkali during alkali refining; the alkali is selected from at least one of potassium hydroxide and sodium hydroxide;

[0041] 5) The amount of the alkali used is 0.3-0.5% of the mass of the crude product of polyglycerol-3 diisostearate.

[0042] Preferably, the alkali is potassium hydroxide and sodium hydroxide in a mass ratio of 1:1.

[0043] Preferably, the alkali refining is carried out under normal pressure.

[0044] Preferably, the alkali refining comprises diluting the crude polyglyceryl-3 diisostearate; and the dilution solvent comprises cyclohexane.

[0045] Preferably, the specific operation of the alkali refining is:

[0046] The crude product of polyglycerol-3 diisostearate is diluted to reduce the viscosity, heated to 60-100° C., alkali is added, stirred for 20-60 minutes, and the clear liquid is collected by centrifugation.

[0047] Preferably, in step S2, the process parameters of the water washing include at least one of the following parameters:

[0048] 1) The water washing temperature is 50-100°C;

[0049] 2) The washing time is 5 to 30 minutes;

[0050] 3) The stirring rate of the water washing is 100-500 r / min.

[0051] Further preferably, in step S2, the process parameters of the water washing include at least one of the following parameters:

[0052] 1) The water washing temperature is 60-80°C;

[0053] 2) The washing time is 10 to 15 minutes;

[0054] 3) The stirring rate of the water washing is 200-300 r / min.

[0055] Preferably, the specific operation of the water washing is:

[0056] The supernatant obtained from alkali refining is heated to 50-100° C., hot water at 80-90° C. is added, stirred for 5-30 minutes, and the supernatant is collected by centrifugation to obtain a colorless and transparent polyglycerol-3 diisostearate solution.

[0057] Preferably, the amount of hot water added is 5-10% of the mass of the crude product of polyglycerol-3 diisostearate.

[0058] Preferably, in step S3, the concentration temperature is 30-80°C; more preferably, the concentration temperature is 50-60°C.

[0059] Specifically, the concentration is carried out in a vacuum concentration tank, and most of the diluting solvent in the polyglyceryl-3 diisostearate solution is removed by concentration to obtain a concentrated solution.

[0060] Preferably, in step S3, the purification process parameters include at least one of the following parameters:

[0061] 1) The purification temperature is 50-100° C.;

[0062] 2) The speed of the purification is 150-200 r / min;

[0063] 3) The purification pressure is 6-30Pa.

[0064] Preferably, the specific operation of the purification is:

[0065] The concentrated liquid is preheated to 50-100° C., added to a short-path molecular evaporator, the rotation speed is adjusted to 150-200 r / min, the absolute pressure is controlled to 6-30 Pa, and the heavy phase component is taken; the heavy phase component is heated to 70-80° C., and under the control of a quantitative device, it is uniformly introduced into a scraped film molecular distiller, the absolute pressure is controlled to 9-15 Pa, and light yellow transparent polyglycerol-3 diisostearate is obtained.

[0066] The second aspect of the present invention provides the use of polyglycerol-3 diisostearate prepared by the preparation method described in the first aspect of the present invention in the fields of food, daily chemicals, petroleum, coatings, plastics and medicine.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] 1) The preparation method of polyglycerol-3 diisostearate provided by the present invention reduces the generation of reaction by-products and improves the esterification rate by controlling the temperature and pressure at different stages. The obtained polyglycerol-3 diisostearate has low chroma, low odor, high esterification rate, low acid value and good emulsification performance;

[0069] 2) The preparation method of polyglycerol-3 diisostearate provided by the present invention has a temperature of less than 220° C. in the entire preparation process, low energy consumption and low preparation cost;

[0070] 3) The polyglycerol-3 diisostearate prepared by the preparation method of polyglycerol-3 diisostearate provided by the present invention has odor, chromaticity, acid value, saponification value, HLB value, water content, iodine value, esterification rate and heavy metal content that all meet the standard requirements and can meet the application requirements in the fields of food, daily chemicals, petroleum, coatings, plastics and medicine. DETAILED DESCRIPTION

[0071] The present invention is further described in detail below by specific examples. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial sources or can be obtained by prior art methods. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0072] Example 1

[0073] This embodiment provides a method for preparing polyglycerol-3 diisostearate, the steps are as follows:

[0074] S11. Add 5.92 kg of isostearic acid and sodium hydroxide equivalent to 0.5% of the total mass of triglycerol and isostearic acid into a 10L beaker, and stir and dissolve them at 70°C until they are completely dissolved to obtain an isostearic acid mixed solution for later use; weigh 2.0 kg of triglycerol and add it to the esterification reactor, turn on the heating device, vacuum device and stirring device of the reactor, control the pressure of the reactor to -0.05 to -0.08 MPa, and the stirring speed to 90 r / min; when the temperature of the material system in the reactor rises to 80 to 90°C, stir for 20 minutes in this state to remove volatile gases such as air moisture carried in the raw materials; then introduce nitrogen to replace The gas in the device is continuously introduced with nitrogen after three times and the temperature begins to rise to 200°C. When the temperature reaches 195°C, the peristaltic pump is turned on and the prepared isostearic acid mixture is added at a flow rate of 20mL / min. After the addition is completed, the stirring speed is adjusted to 200r / min and the reaction is carried out for 4h. After the end, the pressure is reduced to -0.05~-0.08MPa and the reaction is continued for 2h. Then, the vacuum valve and the heating device are closed first, the nitrogen valve is opened, and the temperature is lowered to 60~70°C; then the nitrogen valve and the stirring device are closed, the vacuum device is turned on, the pressure is reduced to -0.05~-0.08MPa, and it is kept at 60~70°C for 4h to obtain a crude product of polyglycerol-3 diisostearate.

[0075] S21. Dilute the crude product of polyglycerol-3 diisostearate with cyclohexane to reduce the viscosity, heat to 80-100°C, add NaOH and KOH in a mass ratio of 1:1, which is 0.5% of the mass of the crude product of polyglycerol-3 diisostearate, stir at 300 r / min for 35 min, and collect the clear liquid by centrifugation; heat the clear liquid to 60°C, add hot water at 80-90°C, which is 5-10% of the mass of the crude product of polyglycerol-3 diisostearate, stir at 300 r / min for 15 min, and collect the clear liquid by centrifugation to obtain a polyglycerol-3 diisostearate solution.

[0076] S31, pour the above polyglycerol-3 diisostearate solution into a concentration tank, reduce the pressure to -0.05 ~ -0.08MPa, heat to 60 ~ 70 ℃, remove most of the cyclohexane; collect the above concentrated solution and preheat it to 50 ~ 100 ℃, add it to the short-range molecular distillation equipment; adjust the rotation speed of the thin film evaporator to 150 ~ 200r / min, control the absolute pressure to 6 ~ 30Pa, and take the heavy phase component; continue to heat the heavy phase component to 70 ~ 80 ℃, and under the control of the quantitative device, make it evenly enter the wiped film molecular distiller, control the absolute pressure to 9 ~ 15Pa, and the heavy phase component obtained is light yellow transparent polyglycerol-3 diisostearate.

[0077] Example 2

[0078] This embodiment provides a method for preparing polyglycerol-3 diisostearate, the steps are as follows:

[0079] S11. Add 5.92 kg of isostearic acid and sodium hydroxide equivalent to 0.5% of the total mass of triglycerol and isostearic acid into a 10L beaker, and stir and dissolve them at 70°C until they are completely dissolved to obtain an isostearic acid mixed solution for later use; weigh 2.0 kg of triglycerol and add it to the esterification reactor, turn on the heating device, vacuum device and stirring device of the reactor, control the pressure of the reactor to -0.05 to -0.08 MPa, and the stirring speed to 90 r / min; when the temperature of the material system in the reactor rises to 80 to 90°C, stir for 20 minutes in this state to remove volatile gases such as air moisture carried in the raw materials; then introduce nitrogen to replace The gas in the device is continuously introduced with nitrogen after three times and the temperature begins to rise to 200°C. When the temperature reaches 195°C, the peristaltic pump is turned on and the prepared isostearic acid mixture is added at a flow rate of 20mL / min. After the addition is completed, the stirring speed is adjusted to 200r / min and the reaction is carried out for 5h. After the end, the pressure is reduced to -0.05~-0.08MPa and the reaction is continued for 2h. Then, the vacuum valve and the heating device are closed first, the nitrogen valve is opened, and the temperature is lowered to 60~70°C; then the nitrogen valve and the stirring device are closed, the vacuum device is turned on, the pressure is reduced to -0.05~-0.08MPa, and it is kept at 60~70°C for 5h to obtain a crude product of polyglycerol-3 diisostearate.

[0080] S21. Dilute the crude product of polyglycerol-3 diisostearate with cyclohexane to reduce the viscosity, heat to 80°C-90°C, add NaOH and KOH in a mass ratio of 1:1, which is 0.4% of the mass of the crude product of polyglycerol-3 diisostearate, stir at 300 r / min for 30 min, and collect the clear liquid by centrifugation; heat the clear liquid to 70°C, add hot water at 80°C-90°C, which is 5-10% of the mass of the crude product of polyglycerol-3 diisostearate, stir at 300 r / min for 10 min, and collect the clear liquid by centrifugation to obtain a polyglycerol-3 diisostearate solution.

[0081] S31, pour the above polyglycerol-3 diisostearate solution into a concentration tank, reduce the pressure to -0.05 ~ -0.08MPa, heat to 60 ~ 70 ℃, remove most of the cyclohexane; collect the above concentrated solution and preheat it to 50 ~ 100 ℃, add it to the short-range molecular distillation equipment; adjust the rotation speed of the thin film evaporator to 150 ~ 200r / min, control the absolute pressure to 6 ~ 30Pa, and take the heavy phase component; continue to heat the heavy phase component to 70 ~ 80 ℃, and under the control of the quantitative device, make it evenly enter the wiped film molecular distiller, control the absolute pressure to 9 ~ 15Pa, and the heavy phase component obtained is light yellow transparent polyglycerol-3 diisostearate.

[0082] Example 3

[0083] This embodiment provides a method for preparing polyglycerol-3 diisostearate, the steps are as follows:

[0084] S11, add 4.74kg of isostearic acid and sodium hydroxide equivalent to 0.4% of the total mass of triglycerol and isostearic acid into a 10L beaker, stir and dissolve at 70°C until completely, to obtain an isostearic acid mixed solution for standby use; weigh 2.0kg of triglycerol and add it to the esterification reactor, turn on the heating device, vacuum device and stirring device of the reactor, control the pressure of the reactor to -0.05~-0.08MPa, and the stirring speed to 90r / min; when the temperature of the material system in the reactor rises to 80~90°C, stir for 20min in this state to remove volatile gases such as air moisture carried in the raw materials; then introduce nitrogen and place Change the gas in the device, and after three times, continue to introduce nitrogen and start to heat up to 205°C. When the temperature reaches 195°C, turn on the peristaltic pump, add the prepared isostearic acid mixture at a flow rate of 20mL / min, and adjust the stirring speed to 200r / min after the addition is completed, and react for 3h; reduce the pressure to -0.05~-0.08MPa, and continue to react for 2h; then close the vacuum valve and the heating device, open the nitrogen valve, and cool to 60~70°C; then close the nitrogen valve and the stirring device, turn on the vacuum device, reduce the pressure to -0.05~-0.08MPa, and keep it at 60~70°C for 5h to obtain a crude product of polyglycerol-3 diisostearate.

[0085] S21. Dilute the crude product of polyglycerol-3 diisostearate with cyclohexane to reduce the viscosity, heat to 80-90°C, add NaOH and KOH in a mass ratio of 1:1, which is 0.3% of the mass of the crude product of polyglycerol-3 diisostearate, stir at 250r / min for 30min, and collect the clear liquid by centrifugation; heat the clear liquid to 70°C, add hot water at 80-90°C, which is 5-10% of the mass of the crude product of polyglycerol-3 diisostearate, stir at 250r / min for 8min, and collect the clear liquid by centrifugation to obtain a polyglycerol-3 diisostearate solution.

[0086] S31, pour the above polyglycerol-3 diisostearate solution into a concentration tank, reduce the pressure to -0.05 ~ -0.08MPa, heat to 60 ~ 70 ℃, remove most of the cyclohexane; collect the above concentrated solution and preheat it to 50 ~ 100 ℃, add it to the short-range molecular distillation equipment; adjust the rotation speed of the thin film evaporator to 150 ~ 200r / min, control the absolute pressure to 6 ~ 30Pa, and take the heavy phase component; continue to heat the heavy phase component to 70 ~ 80 ℃, and under the control of the quantitative device, make it evenly enter the wiped film molecular distiller, control the absolute pressure to 9 ~ 15Pa, and the heavy phase component obtained is light yellow transparent polyglycerol-3 diisostearate.

[0087] Example 4

[0088] This embodiment provides a method for preparing polyglycerol-3 diisostearate, the steps are as follows:

[0089] S11, add 4.98kg of isostearic acid and sodium hydroxide equivalent to 0.4% of the total mass of triglycerol and isostearic acid into a 10L beaker, stir and dissolve at 70°C until completely, to obtain an isostearic acid mixed solution for standby use; weigh 2.0kg of triglycerol and add it to the esterification reactor, turn on the heating device, vacuum device and stirring device of the reactor, control the pressure of the reactor to -0.05~-0.08MPa, and the stirring speed to 90r / min; when the temperature of the material system in the reactor rises to 80~90°C, stir for 20min in this state to remove volatile gases such as air moisture carried in the raw materials; then introduce nitrogen and place Change the gas in the device, and after three times, continue to introduce nitrogen and start to heat up to 205°C. When the temperature reaches 195°C, turn on the peristaltic pump, add the prepared isostearic acid mixture at a flow rate of 20mL / min, and adjust the stirring speed to 200r / min after the addition is completed, and react for 4h; reduce the pressure to -0.05~-0.08MPa, and continue to react for 1h; then close the vacuum valve and the heating device, open the nitrogen valve, and cool to 60~70°C; then close the nitrogen valve and the stirring device, turn on the vacuum device, reduce the pressure to -0.05~-0.08MPa, and keep it at 60~70°C for 5h to obtain a crude product of polyglycerol-3 diisostearate.

[0090] S21. Dilute the crude product of polyglycerol-3 diisostearate with cyclohexane to reduce the viscosity, heat to 70-80°C, add NaOH and KOH in a mass ratio of 1:1, which is 0.2% of the mass of the crude product of polyglycerol-3 diisostearate, stir at 200 r / min for 30 min, and collect the clear liquid by centrifugation; heat the clear liquid to 70°C, add hot water at 80-90°C, which is 5-10% of the mass of the crude product of polyglycerol-3 diisostearate, stir at 200 r / min for 8 min, and collect the clear liquid by centrifugation to obtain a polyglycerol-3 diisostearate solution.

[0091] S31, pour the above polyglycerol-3 diisostearate solution into a concentration tank, reduce the pressure to -0.05 ~ -0.08Mpa, heat to 60 ~ 70 ℃, remove most of the cyclohexane; collect the above concentrated solution and preheat it to 50 ~ 100 ℃, add it to the short-range molecular distillation equipment; adjust the rotation speed of the thin film evaporator to 150 ~ 200r / min, control the absolute pressure to 6 ~ 30Pa, and take the heavy phase component; continue to heat the heavy phase component to 70 ~ 80 ℃, and under the control of the quantitative device, make it evenly enter the scraped film molecular distiller, control the absolute pressure to 9 ~ 15Pa, and the heavy phase component obtained is light yellow transparent polyglycerol-3 diisostearate.

[0092] Performance Testing

[0093] The chromaticity, odor, acid value, saponification value, refractive index, hydrophile-lipophile balance (HLB value), water content and esterification rate of the polyglycerol-3 diisostearate prepared in Examples 1-4 were tested.

[0094] Among them, the saponification value generally refers to the number of milligrams of potassium hydroxide required to convert 1g of oil into fatty acid salts when the oil reacts with potassium hydroxide under alkaline conditions. It can reflect the content of fatty acids in the oil and indirectly reflect the quality of the oil. It is related to the hydrolysis ability of the oil under alkaline conditions; the HLB value reflects the hydrophilicity and lipophilicity of the surfactant, which is used to guide the application of surfactants in specific systems and is related to the distribution and emulsification ability of the surfactant at the oil-water interface.

[0095] The test method is as follows:

[0096] 1) Chroma: Tested in accordance with GB 3143-1982 “Color determination of liquid chemical products”;

[0097] 2) Smell: Determine whether there is a pungent smell through the sense of smell;

[0098] 3) Acid value: Tested in accordance with GBT 5530-2005 "Determination of acid value and acidity of animal and vegetable oils and fats";

[0099] 4) Saponification value: Tested in accordance with GB / T 5534-2008 "Determination of Saponification Value of Animal and Vegetable Fats and Oils";

[0100] 5) HLB value: Determined by water number method, the specific steps are:

[0101] ① Determination of HLB value standard curve:

[0102] a. Prepare the oil phase: use a 250mL volumetric flask to prepare 200mL of a mixed solution of isopropanol and toluene in a mass ratio of 100:15;

[0103] b. Prepare standard samples with different HLB values ​​(at least 10 samples): Take Span 80 (HLB = 4.3) and Tween 80 (HLB = 15) as standard products; take a 25 mL volumetric flask (or conical flask), accurately measure 5.8 mL of the prepared oil phase in each flask and set aside; use Span 80 and Tween 80 to prepare a series of emulsifiers with different HLB values ​​with a total mass of 0.5 g, add them to the volumetric flask (or conical flask) containing 5.8 mL of the oil phase, accurately weigh, shake well, and heat to 30°C in a water bath;

[0104] c. Distilled water titration: Titrate the sample with distilled water until the sample becomes blurred (unified standard), and record the amount of water used (mL);

[0105] d. Draw the HLB standard curve: Use the lg value of the milliliters of distilled water as the horizontal axis and the HLB value as the vertical axis to establish a plane rectangular coordinate system.

[0106] ② Determination of HLB value of polyglyceryl-3 diisostearate:

[0107] Weigh 0.5 g of each of the polyglyceryl-3 diisostearate in Examples 1-4 and add them to a volumetric flask (or conical flask) containing 5.8 mL of the oil phase. Follow the same steps as above, record the amount of water, and bring its 1 g value into the obtained rectangular coordinate system to obtain the HLB value of polyglyceryl-3 diisostearate.

[0108] 6) Refractive index: refer to GB 6488-2008 "Determination of refractive index of liquid chemical products" and test at 20°C using Abbe refractometer BM-2WAJ;

[0109] 7) Water content: Tested in accordance with GB / T 11275-2007 "Determination of water content of surfactants";

[0110] 8) Iodine value: Tested in accordance with GB / T 5532-2008 "Determination of iodine value of animal and vegetable fats and oils";

[0111] 9) Heavy metal content: Tested in accordance with GB 5009.268-2016 "National Food Safety Standard - Determination of Multiple Elements in Food";

[0112] 10) Esterification rate: calculated by the acid value before and after the reaction, the calculation formula is:

[0113] Esterification rate = (acid value before reaction - acid value after reaction) / acid value before reaction * 100%.

[0114] Table 1 is the reference standard values ​​of the performance of polyglycerol-3 diisostearate, and Table 2 is the performance test results of polyglycerol-3 diisostearate in Examples 1-4.

[0115] Table 1 Performance reference standard values ​​of polyglycerol-3 diisostearate

[0116] Test items Reference standard value odor Odorless or with a slight characteristic odor Hazen ≤40 Acid value (mgKOH / g) ≤0.5 Saponification value (mgKOH / g) ≥140 HLB value 5.2-6.0 Refractive index (20℃) 1.4800-1.4890 Water content% ≤1 Iodine value (g / 100g) ≤0.5 Esterification rate% ≥99 Heavy metal content (ppm) ≤20

[0117] Table 2 Performance test results of polyglycerol-3 diisostearate in Examples 1-4

[0118]

[0119] As shown in Table 2, the polyglyceryl-3 diisostearate prepared in Examples 1-4 has only a slight characteristic odor, and the chromaticity, acid value, saponification value, HLB value, water content, iodine value, esterification rate and heavy metal content all meet the standard requirements, and the refractive index is also close to the standard value. Among them, the acid value of polyglyceryl-3 diisostearate is low, indicating that it is less irritating, and can be used as a cosmetic additive, and can also provide emulsification and moisturizing properties simultaneously.

[0120] By adopting the preparation method provided by the present invention, under the condition that the system temperature is less than 220° C., polyglycerol-3 diisostearate with low chroma, low odor, low acid ester, high esterification rate and good emulsification performance can be obtained, which not only avoids the problem that the final product has high chroma and strong odor due to oxidation, cyclization and other reactions of inorganic base, triglycerol and isostearic acid at high temperature, but also reduces energy consumption and cost. The obtained product can meet the application requirements in the fields of food, daily chemicals, petroleum, coatings, plastics and medicine.

Claims

1. A method for preparing polyglycerol-3 diisostearate, characterized in that: The following steps are involved: S1, after degassing the triglycerol, replace the air, heat to 195-220°C under a protective atmosphere, and start to drip a mixed solution of a catalyst and isostearic acid into the degassed triglycerol at 195°C, and stir the reaction at a rate of 150-220r / min for 3-5h after the dripping is completed; after the completion, close the protective atmosphere and reduce the pressure to -0.05-0.08MPa, and continue the reaction for 1-3h; then restore the pressure, introduce the protective atmosphere, and cool to 60-70°C, then close the protective atmosphere and reduce the pressure to -0.05-0.08MPa, and let it stand for 3-5h to obtain a crude product of polyglycerol-3 diisostearate; S2, the crude product of polyglycerol-3 diisostearate is smelted with alkali and washed with water to obtain a polyglycerol-3 diisostearate solution; S3. The polyglyceryl-3 diisostearate solution is concentrated and purified to obtain the polyglyceryl-3 diisostearate.

2. The preparation method according to claim 1, characterized in that: In the step S1, the process parameters of the triglycerol degassing treatment include at least one of the following parameters: 1) The degassing pressure is -0.05 to -0.08 MPa; 2) The degassing temperature is 70-90°C; 3) The degassing time is 10 to 20 minutes; 4) The stirring rate of the degassing is 80-100 r / min.

3. The preparation method according to claim 1, characterized in that: In the step S1, the mixed solution of the catalyst and isostearic acid is prepared by a method comprising the following steps: heating and dissolving the catalyst in isostearic acid to obtain the mixed solution; Preferably, the temperature of the heating and dissolving is 70-90°C.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The molar ratio of the triglycerol to isostearic acid is 1:(1.5-3).

5. The preparation method according to any one of claims 1 to 3, characterized in that: The amount of the catalyst added is 0.1 to 1% of the total mass of the triglycerol and isostearic acid; Preferably, the catalyst is selected from at least one of alkali metal hydroxides, alkali metal carbonates and alkali metal alkoxides.

6. The preparation method according to claim 1, characterized in that: In step S2, the process parameters of the alkali refining include at least one of the following parameters: 1) The alkali refining temperature is 60-100°C; 2) the alkali refining time is 20 to 60 minutes; 3) The stirring rate of the alkali refining is 100-600 r / min; 4) adding alkali during alkali refining; the alkali is selected from alkali metal hydroxides; 5) The amount of the alkali used is 0.1-0.8% of the mass of the crude product of polyglycerol-3 diisostearate.

7. The preparation method according to claim 1, characterized in that: In step S2, the process parameters of the water washing include at least one of the following parameters: 1) The water washing temperature is 50-100°C; 2) The washing time is 5 to 30 minutes; 3) The stirring rate of the water washing is 100-500 r / min.

8. The preparation method according to claim 1, characterized in that: In the step S3, the concentration temperature is 30-80°C.

9. The preparation method according to claim 1, characterized in that: In step S3, the purification process parameters include at least one of the following parameters: 1) The purification temperature is 50-100° C.; 2) The speed of the purification is 150-200 r / min; 3) The purification pressure is 6-30Pa.

10. Application of polyglycerol-3 diisostearate obtained by the preparation method according to any one of claims 1 to 9 in the fields of food, daily chemicals, petroleum, coatings, plastics and medicine.

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