A modified hydrotalcite-based oil ethoxylation catalyst, a preparation method and application thereof

Abstract

The application discloses a modified hydrotalcite-based oil ethoxylation catalyst and a preparation method and application thereof, relates to the technical field of fatty acid ester ethoxylation catalyst preparation, and adopts an ion exchange method to prepare a modified hydrotalcite-based oil ethoxylation catalyst. The catalyst has the advantages of high catalytic activity, high raw material (ethylene oxide) conversion rate and long service life, and the catalyst can recover the catalytic activity through simple activation and regeneration, can be industrially produced and put into use. Meanwhile, the product produced by using the catalyst prepared by the application has good color, is milky white (colorless and transparent liquid after melting), has narrow relative molecular weight distribution and low by-product (polyethylene glycol and dioxane) content.

Description

Technical Field

[0001] This invention relates to the field of fatty acid ester ethoxylation catalyst preparation technology, and in particular to an oil ethoxylation catalyst based on modified hydrotalcite, its preparation method and application. Background Technology

[0002] Nonionic surfactants are surfactants whose molecules contain ether groups that do not dissociate in aqueous solution as the main hydrophilic group, and their surface activity is exhibited by neutral molecules. Nonionic surfactants possess high surface activity, good solubilizing, detergency, antistatic, and calcium soap dispersing properties, low irritation, and excellent wetting and detergency functions. They have a wider applicable pH range than general ionic surfactants and can be used in combination with other ionic surfactants. Adding a small amount of nonionic surfactant to an ionic surfactant can improve the surface activity of the system.

[0003] Nonionic surfactants can be classified into polyoxyethylene type, polyol type, alkanolamide type, polyether type, and amine oxide type according to the structure of their hydrophilic groups. Among them, the production of polyoxyethylene type surfactants requires the use of compounds containing active hydrogen, such as alcohols, phenols, carboxylic acids, and amides, as raw materials, which are polymerized with epoxy compounds such as ethylene oxide or propylene oxide under acidic or alkaline catalytic conditions.

[0004] Polyoxyethylene ester products are non-toxic and non-irritating; they have good skin compatibility and can reduce the irritation of formulated products; in particular, their triglyceride structure provides excellent emulsifying properties and superior oil solubilizing ability for edible oils and mineral oils. Polyoxyethylene ester products have the following characteristics: ① The product itself has a certain viscosity, thus having a significant thickening effect on anionic systems; ② The product itself is a medium-foaming product and has no significant inhibitory effect on foam in the formulated system; ③ The product has good fat-enriching properties and can be used to enhance the conditioning of personal protective products; ④ The product's HLB value is adjustable, and it has excellent properties such as good low-temperature solubility, resistance to hard water, easy biodegradability, and good lubricity, making it suitable for use in dishwashing detergents, oil phase conditioners, food emulsifiers, leather fatliquoring agents, metal cutting fluids, and some synthetic fiber oils. However, for ester-based reaction substrates, due to the lack of active hydrogen, ordinary acidic or basic catalysts have almost no catalytic activity. To obtain polyoxyethylene ester surfactants, a two-step process is required: 1. ethoxylation of the carboxylic acid or alcohol substrate; 2. esterification of the product from the first step. This two-step synthesis process is cumbersome and costly. Literature reports that using magnesium-aluminum composite metal oxides as catalysts allows for the direct one-step ethoxylation of ester compounds with ethylene oxide. However, this method has low catalytic efficiency, low reaction conversion rate, and numerous byproducts. The following technical solutions exist for preparing magnesium-aluminum composite metal oxide catalysts for the ethoxylation of long-chain alkane monoesters as substrates:

[0005] Magnesium oxide was dispersed in pure water, and a certain amount of aluminum nitrate aqueous solution was added to impregnate the magnesium oxide surface with aluminum ions. The resulting powder was filtered, rinsed, dried, and then calcined to obtain a magnesium-aluminum composite metal oxide catalyst (aluminum content of 0.8-3.0%, calcination temperature of 400-950℃).

[0006] A certain amount of methyl laurate and catalyst were placed in an autoclave, and the air inside the autoclave was purged with nitrogen. The mixture was then heated, and a certain amount of ethylene oxide was introduced into the autoclave, maintaining the temperature at 180°C and the pressure at 3 atm. After aging and cooling, the reaction mixture was filtered to remove the catalyst, yielding EFME. The optimal reactivity was 0.53 g-EO·min. -1 ·g-cat -1 .

[0007] Patent document CN102558411B discloses "a preparation process of an ether ester copolymer water-reducing agent". The ethoxy catalyst used in the preparation process includes: 30-90 wt% alkaline earth metal oxide, 1-40 wt% group III metal ions, and 1-30 wt% support.

[0008] Patent document CN1730145A discloses "an ethoxylated oil and its preparation method", which includes: adding 2.6g of catalyst to 90g of soybean oil, stirring while adding it to a 1L high-pressure reactor, turning on the stirrer, replacing the air with nitrogen, heating to 180℃, introducing ethylene oxide, maintaining the system pressure at 0.4MPa, and when the amount of ethylene oxide added is 238g, closing the EO feed valve, aging for 10min, cooling to 70℃, releasing the material, weighing 329.5g, and obtaining a product with an average single-chain oxyethylene content of 18.0 - soybean oil ethoxylated oil.

[0009] Most commercially available nonionic surfactants are alcohols, carboxylic acids, and other compounds containing active hydrogen. These are ethoxylated under the action of a catalyst to yield fatty alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers, and fatty acid polyoxyethylene esters. However, catalysts for the ethoxylation of fatty acid esters are relatively rare, and their catalytic activity is mostly around 1.0 g-EO·min⁻¹. -1 ·g-cat -1 about. Summary of the Invention

[0010] The purpose of this invention is to provide a modified hydrotalcite-based ester ethoxylation catalyst, its preparation method, and its application. The ester ethoxylation catalyst of this invention has the advantages of high catalytic activity, high conversion rate of raw material (ethylene oxide), and long service life. Furthermore, the catalyst can be restored to its catalytic activity through simple activation and regeneration, allowing for industrial production and application. Simultaneously, the product produced using the catalyst prepared by this patent has excellent color, being milky white (becoming a colorless and transparent liquid after melting), with a narrow relative molecular weight distribution and low content of byproducts (polyethylene glycol dioxane).

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] This invention provides a method for preparing an ethoxylation catalyst for oils and fats based on modified hydrotalcite, the method comprising the following steps:

[0013] Step S1: Weigh magnesium salt, aluminum salt and urea, add solvent to dissolve, heat and stir under reflux to obtain a white suspension;

[0014] Step S2: Allow the white suspension to cool naturally and filter; add deionized water to the filter cake, stir well, and filter; repeat this process three times until the filtrate is neutral; dry the filter cake to obtain magnesium aluminum hydrotalcite.

[0015] Step S3: Weigh the dried magnesium aluminum hydrotalcite and organic acid, dissolve them in ethanol, heat and stir under reflux, cool naturally and filter, dry the filter cake to obtain magnesium aluminum hydrotalcite containing organic acid intercalation.

[0016] Step S4: Grind the magnesium aluminum hydrotalcite containing organic acid intercalation, first by heating up the temperature program, and then by cooling down the temperature program to room temperature.

[0017] Further, in step S1, the molar ratio of the magnesium salt to the aluminum salt is 1:1 to 9:1; the molar ratio of urea to the magnesium salt is 3:1 to 10:1, wherein,

[0018] The magnesium salt is one of magnesium nitrate hexahydrate, magnesium sulfate heptahydrate, or magnesium chloride hexahydrate;

[0019] The aluminum salt is one of aluminum nitrate nonahydrate, aluminum chloride hexahydrate, or aluminum sulfate octahydrate.

[0020] Further, in step S1, the solvent is one or more of ethanol, distilled water, ethylene glycol, or glycerol.

[0021] Furthermore, in step S1, the reflux conditions include: a temperature of 140–180°C and a time of 2–24 hours.

[0022] Further, in step S3, the mass ratio of the magnesium aluminum hydrotalcite to the organic acid is 5:1 to 1:1; the reflux conditions include a temperature of 50 to 130°C and a time of 0.5 to 12 hours.

[0023] Further, in step S3, the organic acid is one of acetic acid, lauric acid, arachidic acid, citric acid, malic acid, or ricinoleic acid.

[0024] Furthermore, in step S4, the initial temperature of the programmed heating is 25°C, the heating rate is 1–20°C / min, the termination temperature is 300–800°C, and the holding time is 0.5–10h.

[0025] The present invention also provides an ethoxylation catalyst for oils based on modified hydrotalcite, which is prepared by the method described above.

[0026] This invention also provides an application of the modified hydrotalcite-based ethoxylation catalyst for oils and fats described above, wherein the catalyst is used for the ethoxylation reaction of fatty acid ester substrates; wherein,

[0027] The fatty acid esters include: natural animal and vegetable oils and C. 8-20 Triglycerides; vegetable oils include rapeseed oil, cottonseed oil, coconut oil, palm oil, olive oil, palm kernel oil, litsea cubeba oil, rice bran oil, or nutmeg oil; animal oils include tallow, mutton tallow, or lard.

[0028] The technical effects and advantages of this invention are as follows:

[0029] (1) Natural animal and vegetable oils often do not contain active hydrogen and are difficult to ethoxylate. Traditional acid catalysts (such as sulfuric acid, phosphoric acid, aluminum chloride, etc.) or alkaline catalysts (such as sodium hydroxide, potassium hydroxide, etc.) do not have good catalytic effects. The magnesium-aluminum composite metal oxide prepared in this invention is a solid acid-base bifunctional catalyst. It contains both alkaline active sites generated by magnesium oxide and acidic active sites generated by aluminum oxide. Furthermore, the solid catalyst and the product are easy to separate.

[0030] (2) Most existing magnesium-aluminum composite metal oxide catalysts are prepared by impregnation, where aluminum ions are impregnated onto the surface of magnesium oxide or a support. Due to limitations in the preparation method, this method cannot produce magnesium-aluminum composite metal catalysts with high aluminum content. However, the higher the aluminum ion content, the more acidic active sites are provided, and the higher the catalytic activity. The method of this invention can prepare composite metal oxide catalysts with high aluminum content, and the aluminum content of the catalyst can be arbitrarily controlled.

[0031] (3) The present invention uses organic acids to modify magnesium aluminum hydrotalcite to obtain hydrotalcite containing organic acid intercalation, which greatly improves catalytic activity.

[0032] (4) Due to the simple preparation process of the catalyst of the present invention, the raw materials are cheap and readily available, the catalyst has high catalytic activity, few by-products, high selectivity, long service life, and easy regeneration, it is more suitable for industrial production. The present invention uses magnesium-aluminum hydrotalcite containing organic acids. As a result, the magnesium-aluminum composite metal oxide obtained after calcination has higher catalytic activity, the conversion rate of raw material (ethylene oxide) is as high as 98% or more, the product has a light color and a narrow relative molecular weight distribution, and the content of by-products polyethylene glycol and dioxane is less than 0.1% and 10 ppm, respectively. The existing technical solutions do not mention the conversion rate of ethylene oxide and the content of by-products.

[0033] (5) The catalyst prepared by this invention has a catalytic activity of 3.0 g-EO·min. -1 ·g-cat -1 This significantly surpasses existing technologies. Furthermore, the catalyst prepared by this invention exhibits 90% of the catalytic activity of a fresh catalyst after 50 hours of continuous production and 85% after 100 hours. The catalytic activity of the used catalyst can be restored to over 97% of that of a fresh catalyst through simple activation and regeneration. Existing technologies only demonstrate catalyst stability after 12 reuses, and their catalytic activity decreases to 80% after one year of storage and below 40% after 1.5 years of storage without use, and cannot be restored through catalyst regeneration.

[0034] (6) Existing technical solutions mainly target long-chain fatty acid monoester substrates, with methyl laurate being the most common. The catalyst prepared in this invention is not only suitable for common lipid compounds such as ethyl acetate and butyl acetate, but also for long-chain fatty acid triglyceride substrates, mainly castor oil and hydrogenated castor oil, and other animal and vegetable oils. Compared with monoester substrates, triglyceride substrates have greater steric hindrance and are more difficult to react.

[0035] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1This is a morphological illustration of the catalyst product prepared in Example 1 of the present invention;

[0038] Figure 2 This is a morphological illustration of the catalyst product prepared in Example 2 of the present invention;

[0039] Figure 3 This is a morphological illustration of the catalyst product prepared in Example 3 of the present invention;

[0040] Figure 4 This is a pictorial illustration of the product of Test Example 1 of the present invention - polyoxyethylene hydrogenated castor oil;

[0041] Figure 5 The relative molecular mass distribution of the product of Test Example 1 of this invention - polyoxyethylene (40) hydrogenated castor oil;

[0042] Figure 6 The image shows the properties of the product from Test Example 3 of this invention – polyoxyethylene hydrogenated castor oil. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] The first objective of this invention is to provide a method for preparing an ethoxylation catalyst for oils based on modified hydrotalcite, the method comprising the following steps:

[0045] Step S1: Weigh magnesium salt, aluminum salt, and urea into a flask, add solvent to dissolve, connect a reflux condenser, heat and stir under reflux to obtain a white suspension; wherein the molar ratio of magnesium salt to aluminum salt is 1:1 to 9:1; the molar ratio of urea to magnesium salt is 3:1 to 10:1; wherein the magnesium salt includes one or more of magnesium nitrate hexahydrate, magnesium sulfate heptahydrate, or magnesium chloride hexahydrate; the aluminum salt includes one or more of aluminum nitrate nonahydrate, aluminum chloride hexahydrate, or aluminum sulfate octadecahydrate; the solvent includes one or more of ethanol, distilled water, ethylene glycol, or glycerol, preferably a mixed solvent of ethylene glycol and water in a volume ratio of 9:1;

[0046] Step S2: Allow the obtained white suspension to cool naturally and filter; add 500-600 mL of deionized water to the filter cake and stir well, then filter; repeat this process three times until the filtrate is neutral; dry the filter cake to obtain magnesium aluminum hydrotalcite (Mg-Al-CO3-LDH);

[0047] Step S3: Weigh the dried magnesium-aluminum hydrotalcite (Mg-Al-CO3-LDH) and organic acid, dissolve them in ethanol, connect a condenser, add stirring and reflux, allow to cool naturally, filter, and dry the filter cake to obtain magnesium-aluminum hydrotalcite containing organic acid intercalation. The mass ratio of magnesium-aluminum hydrotalcite to organic acid is 5:1 to 1:1; the reflux temperature is 50 to 130°C, and the reflux time is 0.5 to 12 hours; the organic acid includes acetic acid, lauric acid, arachidic acid, citric acid, malic acid, ricinoleic acid, etc.

[0048] Step S4: Weigh and grind the magnesium aluminum hydrotalcite containing organic acid intercalation, place it in a crucible, and program the temperature in a muffle furnace to increase and then program the temperature to room temperature to obtain the catalyst. The initial temperature of the programmable temperature increase is 25℃, the heating rate is 1–20℃ / min, the final temperature is 300–800℃, and the holding time is 0.5–10 h.

[0049] The second objective of this invention is to provide an ethoxylation catalyst for oils based on modified hydrotalcite, wherein calcined hydrotalcite is used to obtain a magnesium-aluminum composite metal oxide as the catalyst; hydrotalcite containing organic acids is synthesized by ion exchange method, and the small molecules of organic acids are used to change the interlayer structure of magnesium-aluminum hydrotalcite, thereby achieving the purpose of hydrotalcite modification; and the magnesium-aluminum composite metal oxide is obtained by calcining it as the catalyst.

[0050] A third objective of this invention is to provide an application of a catalyst with a narrow distribution for the ethoxylation of fatty acid glycerides. The magnesium-aluminum composite metal oxide prepared in this invention serves as the catalyst for the ethoxylation reaction of fatty acid ester substrates; wherein the fatty acid esters include: natural animal and vegetable oils and C... 8-20 Triglycerides can be found in vegetable oils such as rapeseed oil, cottonseed oil, coconut oil, palm oil, olive oil, palm kernel oil, litsea cubeba oil, rice bran oil, or nutmeg oil; and in animal oils such as tallow, mutton tallow, or lard.

[0051] The reagents used in this invention include: magnesium nitrate hexahydrate (Mg(NO2)2·6H2O), aluminum nitrate nonahydrate (Al(NO2)3·9H2O), anhydrous sodium carbonate (Na2CO3), urea (CH4N2O), citric acid (C6H8O7), arachidic acid, lauric acid, acetic acid, malic acid, ethylene glycol, ethanol, isopropanol, distilled water (self-made), and hydrogenated castor oil. All the above reagents were collected from Sinopharm Group and were of analytical grade. The hydrogenated castor oil (98%) was produced by Maclean's. Methyl laurate (analytical grade) and ethylene oxide (EO) (provided by Wuhan Totem Industry and Trade Development Co., Ltd.)

[0052] Example 1:

[0053] Preparation method of catalyst 1: Accurately weigh magnesium nitrate hexahydrate (15.38 g, 0.06 mol), aluminum nitrate nonahydrate (11.28 g, 0.03 mol), and urea (18.0 g, 0.30 mol), dissolve them in a mixed solvent of ethylene glycol and water (540 mL + 60 mL), reflux at 160 °C for 6 h; after natural cooling, filter, add 600 mL of deionized water to the filter cake, stir for 15 min, filter, repeat this process three times until the filtrate is neutral; dry the filter cake at 90 °C for 12 h; grind the dried filter cake, add citric acid (3.78 g, 0.018 mol) and 400 mL of ethanol, reflux at 70 °C for 2 h; after natural cooling, filter, dry and grind the filter cake, place it in a muffle furnace, raise the temperature to 500 °C at a rate of 5 °C / min from room temperature, hold for 1 h, and then cool naturally to obtain catalyst 1. Figure 1 The image shown is a morphological illustration of the catalyst product prepared in Example 1 of this invention. Figure 1 As shown, catalyst 1 is a white powdery solid with a particle size of 200 mesh.

[0054] Example 2:

[0055] Preparation method of catalyst 2: Accurately weigh magnesium nitrate hexahydrate (15.38 g, 0.06 mol), aluminum nitrate nonahydrate (11.28 g, 0.03 mol), and urea (18.0 g, 0.30 mol), dissolve them in a mixed solvent of ethylene glycol and water (540 mL + 60 mL), reflux at 160 °C for 6 h; after natural cooling, filter, add 600 mL of deionized water to the filter cake, stir for 15 min, filter, repeat this process three times until the filtrate is neutral; dry the filter cake at 90 °C for 12 h; grind the dried filter cake, add lauric acid (3.6 g, 0.018 mol) and 400 mL of ethanol, reflux at 70 °C for 2 h; after natural cooling, filter, dry and grind the filter cake, place it in a muffle furnace, raise the temperature to 500 °C at a rate of 5 °C / min from room temperature, hold for 1 h, and then cool naturally to obtain catalyst 2. Figure 2 The image shown is a morphological illustration of the catalyst product prepared in Example 2 of this invention. Figure 2 As shown, catalyst 2 is a pale yellow powder solid with a particle size of 200 mesh.

[0056] Example 3:

[0057] Preparation method of catalyst 3: Accurately weigh magnesium nitrate hexahydrate (15.38 g, 0.06 mol), aluminum nitrate nonahydrate (11.28 g, 0.03 mol), and urea (18.0 g, 0.30 mol), dissolve them in a mixed solvent of ethylene glycol and water (540 mL + 60 mL), reflux at 160 °C for 6 h; after natural cooling, filter, add 600 mL of deionized water to the filter cake, stir for 15 min, filter, repeat this process three times until the filtrate is neutral; dry the filter cake at 90 °C for 12 h; grind the dried filter cake, add arachidic acid (5.6 g, 0.018 mol) and 400 mL of ethanol, reflux at 70 °C for 2 h; after natural cooling, filter, dry and grind the filter cake, place it in a muffle furnace, raise the temperature to 500 °C at a rate of 5 °C / min from room temperature, hold for 1 h, and then cool naturally to obtain catalyst 3. Figure 3 The image shown is a morphological illustration of the catalyst product prepared in Example 3 of this invention. Figure 3 As shown, catalyst 3 is a dark brown powder solid with a particle size of 200 mesh.

[0058] Test Example 1:

[0059] Catalyst 1 Activity Test: 70g of hydrogenated castor oil and 2.8g of Catalyst 1 were added to a 500mL autoclave. The temperature was raised to 90℃, and low-boiling-point substances and water were removed from the system under vacuum. Nitrogen gas was introduced at 0.3MPa, purged to 0.01MPa three times, and the temperature was raised to 180℃. 5g of ethylene oxide was introduced to initiate the reaction. When the pressure dropped to 0.1MPa, ethylene oxide was continuously introduced (maintaining the pressure inside the autoclave at 0.4MPa). The ethylene oxide consumption was calculated using the electronic balance subtraction method. The introduction of ethylene oxide was stopped when the amount added was 130g. The reaction was aged until the pressure was constant, cooled to 90℃, and ethylene oxide gas was removed from the reaction system under vacuum. The product was weighed, the apparent additive weight was calculated to be 40, and the catalytic activity of the catalyst was calculated to be 3.15g-EO·min. -1 ·g-cat -1 , Figure 4 This is a pictorial illustration of the product from Test Example 1 of the present invention—polyoxyethylene hydrogenated castor oil. Figure 5 The relative molecular mass distribution of the product of Test Example 1 of this invention - polyoxyethylene (40) hydrogenated castor oil is shown in the figure. Figure 4-5 As shown, the product - polyoxyethylene hydrogenated castor oil is a milky white paste with a light color and no impurities. The relative molecular mass distribution diagram of the product - polyoxyethylene (40) hydrogenated castor oil shows that its average relative molecular mass is about 3300 and the relative molecular mass distribution is relatively narrow.

[0060] Test Example 2:

[0061] Catalyst 1 activity test:

[0062] 70g of methyl laurate and 2.8g of catalyst 1 were added to a 500mL autoclave. The temperature was raised to 90℃, and low-boiling-point substances and water were removed from the system under vacuum. Nitrogen gas was introduced at 0.3MPa, then purged to 0.01MPa three times. The temperature was raised to 180℃, and 5g of ethylene oxide was introduced to initiate the reaction. When the pressure dropped to 0.1MPa, ethylene oxide was continuously introduced (maintaining the pressure inside the autoclave at 0.4MPa). The consumption of ethylene oxide was calculated using the electronic balance subtraction method. The introduction of ethylene oxide was stopped when 130g of ethylene oxide had been added. The reaction was aged until the pressure reached a constant, cooled to 90℃, and ethylene oxide gas was removed from the reaction system under vacuum. The catalytic activity of the catalyst was calculated to be 4.5g-EO·min. -1 ·g-cat -1 .

[0063] Test Example 3:

[0064] Catalyst 2 activity test:

[0065] 70g of hydrogenated castor oil and 2.8g of catalyst 2 were added to a 500mL autoclave. The temperature was raised to 90℃, and low-boiling-point substances and water were removed from the system under vacuum. Nitrogen gas was introduced at 0.3MPa, purged to 0.01MPa three times, and the temperature was raised to 180℃. 5g of ethylene oxide was introduced to initiate the reaction. When the pressure dropped to 0.1MPa, ethylene oxide was continuously introduced (maintaining the pressure inside the autoclave at 0.4MPa). The consumption of ethylene oxide was calculated using the electronic balance subtraction method. The introduction of ethylene oxide was stopped when 130g of ethylene oxide was added. The reaction was aged until the pressure was constant, cooled to 90℃, and ethylene oxide gas was removed from the reaction system under vacuum. The product was weighed, the apparent additive weight was calculated to be 40, and the catalytic activity of the catalyst was calculated to be 3.45g-EO·min. -1 ·g-cat -1 , Figure 6 The image shown is a pictorial representation of the product from Test Example 3 of this invention—polyoxyethylene hydrogenated castor oil. Figure 6 As shown, the product - polyoxyethylene hydrogenated castor oil - is a milky white paste, light in color, and free of impurities.

[0066] Test Example 4:

[0067] Catalyst 3 activity test:

[0068] 70g of butyl acetate and 2.8g of catalyst 3 were added to a 500mL autoclave. The temperature was raised to 90℃, and low-boiling-point substances and water were removed from the system under vacuum. Nitrogen gas was introduced at 0.3MPa, purged to 0.01MPa three times, and the temperature was raised to 180℃. 5g of ethylene oxide was introduced to initiate the reaction. When the pressure dropped to 0.1MPa, ethylene oxide was continuously introduced (maintaining the pressure inside the autoclave at 0.4MPa). The consumption of ethylene oxide was calculated using the electronic balance subtraction method. The introduction of ethylene oxide was stopped when the amount added was 130g. The reaction was aged until the pressure was constant, cooled to 90℃, and ethylene oxide gas was removed from the reaction system under vacuum. The product was weighed, the apparent additive weight was calculated to be 40, and the catalytic activity of the catalyst was calculated to be 4.2g-EO·min. -1 ·g-cat -1 .

[0069] In summary, the fatty acid glyceride ethoxylation catalyst of the present invention exhibits high catalytic activity (greater than 3.0).

[0070] g-EO·min -1 ·g-cat -1 The catalyst exhibits a 98% conversion rate for the raw material (ethylene oxide), a lifespan of up to 100 hours, and its catalytic activity can be restored through simple activation and regeneration. It can be industrially produced and put into use. Products manufactured using the catalyst prepared according to this invention have excellent color, being milky white (and becoming a colorless, transparent liquid after melting), with a narrow relative molecular weight distribution, and the content of the byproduct polyethylene glycol dioxane is less than 0.1% and 10 ppm.

[0071] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of a modified hydrotalcite catalyst in the ethoxylation of oils and fats, characterized in that, The catalyst is used for the ethoxylation reaction of fatty acid ester substrates; wherein the fatty acid esters are natural animal and vegetable oils; vegetable oils include rapeseed oil, cottonseed oil, coconut oil, palm oil, olive oil, palm kernel oil, litsea cubeba oil, rice bran oil, or nutmeg oil; animal oils include beef tallow, mutton tallow, or lard; The preparation method of the catalyst includes the following steps: Step S1: Weigh magnesium salt, aluminum salt and urea, add solvent to dissolve, heat and stir under reflux to obtain a white suspension. The reflux conditions include: temperature of 140~180 ℃ and time of 2~24 h. Step S2: Allow the white suspension to cool naturally and filter; add deionized water to the filter cake, stir well, and filter; repeat this process three times until the filtrate is neutral; dry the filter cake to obtain magnesium aluminum hydrotalcite. Step S3: Weigh the dried magnesium aluminum hydrotalcite and organic acid, dissolve them in ethanol, heat and stir under reflux, cool naturally and filter, dry the filter cake to obtain magnesium aluminum hydrotalcite containing organic acid intercalation, wherein the organic acid is one of acetic acid, lauric acid, citric acid, malic acid or ricinoleic acid. Step S4: Grind the magnesium aluminum hydrotalcite containing organic acid intercalation, first program the temperature to rise, then program the temperature to fall back to room temperature. The initial temperature of the program temperature rise is 25 ℃, the heating rate is 1~20 ℃ / min, the final temperature is 300~800 ℃, and the holding time is 0.5~10 h.

2. The application of the modified hydrotalcite catalyst according to claim 1 in the ethoxylation of oils and fats, characterized in that, In step S1, the molar ratio of magnesium salt to aluminum salt is 1:1 to 9:1; the molar ratio of urea to magnesium salt is 3:1 to 10:1, wherein... The magnesium salt is one of magnesium nitrate hexahydrate, magnesium sulfate heptahydrate, or magnesium chloride hexahydrate; The aluminum salt is one of aluminum nitrate nonahydrate, aluminum chloride hexahydrate, or aluminum sulfate octahydrate.

3. The application of the modified hydrotalcite catalyst according to claim 1 in the ethoxylation of oils and fats, characterized in that, In step S1, the solvent is one or more of ethanol, distilled water, ethylene glycol, or glycerol.

4. The application of the modified hydrotalcite catalyst according to claim 1 in the ethoxylation of oils and fats, characterized in that, In step S3, the mass ratio of the magnesium aluminum hydrotalcite to the organic acid is 5:1 to 1:1; the reflux conditions include a temperature of 50 to 130 ℃ and a time of 0.5 to 12 h.

Images