Castor oil-based sulfonate anionic surfactant and preparation method thereof

Abstract

The present invention discloses a castor oil-based sulfonate anionic surfactant and a preparation method thereof. The castor oil-based sulfonate anionic surfactant is prepared using castor oil or alkyl ricinoleate as a raw material and contains both sulfonic acid groups and hydroxyl hydrophilic groups. The castor oil-based sulfonate anionic surfactant of the embodiments of the present invention is prepared using castor oil or alkyl ricinoleate as a raw material, thereby producing a green and sustainable surfactant from renewable biomass resources. Furthermore, the castor oil-based sulfonate anionic surfactant of the present invention is an excellent surfactant that can effectively reduce the surface tension of aqueous solutions and exhibits the advantages of good solubility, low foaming, and fine foam.

Description

Technical Field

[0001] The present invention relates to the technical field of surfactants, in particular to a castor oil-based sulfonate anionic surfactant and a preparation method thereof. Background Art

[0002] Surfactants are an important class of fine chemicals, closely intertwined with daily life and industrial production, earning them the nickname "industrial MSG." Commonly used surfactants are mostly synthetic, often derived from petrochemical raw materials. Because petrochemical raw materials are non-renewable, they do not meet the requirements of green chemistry. Therefore, the development of green, sustainable surfactants from renewable biomass resources is an urgent challenge. Summary of the Invention

[0003] The present invention aims to provide a castor oil-based sulfonate anionic surfactant and a preparation method thereof, which can use natural renewable oil as a raw material and can effectively reduce the surface tension of an aqueous solution.

[0004] To achieve the above objectives, an embodiment of the present invention provides a castor oil-based sulfonate anionic surfactant, which is prepared from castor oil or ricinoleic acid alkyl ester as a raw material and contains both a sulfonic acid group and a hydroxyl hydrophilic group.

[0005] In one or more embodiments of the present invention, it has any of the following structural formulas:

[0006]

[0007] Where R is C1~C 12 A saturated hydrocarbon group, R1 and R2 are respectively selected from any one of H and sulfonic acid groups, and R1 and R2 are different.

[0008] In one or more embodiments of the present invention, it has any of the following structural formulas:

[0009]

[0010]

[0011] Where X is any one of K, Na, and NH4, and R is C1~C 12 saturated hydrocarbon group.

[0012] An embodiment of the present invention further provides a method for preparing a castor oil-based sulfonate anionic surfactant, comprising the following steps:

[0013] A mixed reaction system comprising a solid carbon-based base catalyst, a solvent, a bisulfite, castor oil or a ricinoleic acid alkyl ester is subjected to a double bond addition sulfonation reaction to obtain the castor oil-based sulfonate anionic surfactant as described above.

[0014] The alkyl ricinoleate has the following structural formula:

[0015] R is C1~C 12 saturated hydrocarbon group.

[0016] In one or more embodiments of the present invention, the temperature of the double bond addition sulfonation reaction is 30-80° C., and the time is 10-100 h.

[0017] In one or more embodiments of the present invention, the solid carbon-based base catalyst is prepared by calcining an organic compound precursor containing carbon and nitrogen elements.

[0018] In one or more embodiments of the present invention, the organic compound precursor containing carbon and nitrogen elements is any one of porphyrin, dopamine, melamine, dicyandiamide, and urea.

[0019] In one or more embodiments of the present invention, the mass of the solid carbon-based base catalyst is 2% to 30% of the mass of castor oil or ricinoleic acid alkyl ester;

[0020] The molar ratio of castor oil or ricinoleic acid alkyl ester to bisulfite is 1:(1-6);

[0021] The mass ratio of the castor oil or ricinoleic acid alkyl ester to the low-carbon alcohol is 1:(2-5).

[0022] In one or more embodiments of the present invention, the solvent is a combination of a low-carbon alcohol and water, and the mass ratio of the low-carbon alcohol to water is 1:(1-5).

[0023] In one or more embodiments of the present invention, the low-carbon alcohol is any one of ethanol, isopropanol, n-butanol, tert-butanol, and tri-amyl alcohol.

[0024] Compared with the prior art, the castor oil-based sulfonate anionic surfactant according to the embodiment of the present invention is prepared using castor oil or ricinoleic acid alkyl ester as a raw material, and is a green and sustainable surfactant prepared from renewable biomass resources; at the same time, the castor oil-based sulfonate anionic surfactant of the present invention is a surfactant with excellent performance, can effectively reduce the surface tension of aqueous solutions, and has the advantages of good solubility, low foaming, and fine foam. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1is an XRD pattern of a solid carbon-based base catalyst according to one embodiment of the present invention;

[0026] Figure 2 is an infrared spectrum of a castor oil-based sulfonate anionic surfactant according to one embodiment of the present invention;

[0027] Figure 3 is a surface tension diagram of a castor oil-based sulfonate anionic surfactant at different concentrations according to one embodiment of the present invention;

[0028] Figure 4 is a microscopic morphology of foam of a castor oil-based sulfonate anionic surfactant according to one embodiment of the present invention at a concentration of 1.0 g / L; DETAILED DESCRIPTION

[0029] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0030] According to a preferred embodiment of the present invention, a castor oil-based sulfonate anionic surfactant is prepared using castor oil or ricinoleic acid alkyl ester as a raw material, and contains both a sulfonic acid group and a hydroxyl hydrophilic group.

[0031] It is understood that the castor oil-based sulfonate anionic surfactant of the present invention uses castor oil and its derivative ricinoleic acid alkyl ester as raw materials. By selecting a suitable bisulfite as a sulfonating agent and regulating the catalytic sulfonation reaction conditions, the hydroxyl groups are retained and only the addition sulfonation reaction of the carbon-carbon double bond is carried out to graft the hydrophilic sulfonic acid group. The obtained castor oil-based sulfonate sodium salt anionic surfactant contains both hydroxyl groups and sulfonic acid groups. This is a new type of anionic surfactant different from the existing sulfonated castor oil.

[0032] Preferably, the bisulfite may be sodium bisulfite, potassium bisulfite and ammonium bisulfite.

[0033] In one embodiment, the castor oil-based sulfonate anionic surfactant has any of the following structural formulas:

[0034]

[0035] Where R is C1~C 12 A saturated hydrocarbon group, R1 and R2 are respectively selected from any one of H and sulfonic acid groups, and R1 and R2 are different.

[0036] Specifically, the castor oil-based sulfonate anionic surfactant has any of the following structural formulas:

[0037]

[0038] Where X is any one of K, Na, and NH4, and R is C1~C 12 saturated hydrocarbon group.

[0039] It should be noted that when castor oil is used as a raw material to prepare the castor oil-based sulfonate anionic surfactant of the present invention, the sulfonic acid group can be selectively added to the carbons at both ends of the unsaturated double bond, thereby obtaining the following two products:

[0040]

[0041]

[0042] When ricinoleic acid alkyl ester is used as a raw material to prepare the castor oil sulfonate anionic surfactant of the present invention, the sulfonic acid group can be selectively added to the carbons at both ends of the unsaturated double bond, thereby obtaining the following two products:

[0043]

[0044] It is understood that the castor oil-based sulfonate anionic surfactant refers to a surfactant prepared using castor oil or ricinoleic acid alkyl ester as raw material.

[0045] An embodiment of the present invention further provides a method for preparing a castor oil-based sulfonate anionic surfactant, comprising the following steps:

[0046] A mixed reaction system comprising a solid carbon-based base catalyst, a solvent, a bisulfite, and castor oil or a ricinoleic acid alkyl ester is subjected to a double bond addition sulfonation reaction to obtain a castor oil-based sulfonate anionic surfactant;

[0047] Alkyl ricinoleate has the following structural formula:

[0048] R is C1~C 12 saturated hydrocarbon group.

[0049] Specifically, the temperature of the double bond addition sulfonation reaction is 30 to 80° C., and the time is 10 to 100 hours.

[0050] The preparation process of alkyl ricinoleate can be:

[0051] Ricinoleic acid and C1~C 12Fatty alcohol is used as raw material, organic acid p-toluenesulfonic acid is used as catalyst, the amount of p-toluenesulfonic acid catalyst used is 2-10% of the mass of ricinoleic acid, the molar ratio of ricinoleic acid:fatty alcohol is 1:3-6, the reaction temperature is controlled at 50-90°C, and the reaction time is 3-9 hours. After the reaction is completed, ricinoleic acid alkyl ester compounds are obtained through extraction, water washing, drying and reduced pressure distillation.

[0052] In one embodiment, the solid carbon-based base catalyst can be prepared by calcining an organic compound precursor containing carbon and nitrogen elements.

[0053] Specifically, the solid carbon-based base catalyst is calcined at a temperature of 400-700° C. for 2-8 hours. The calcined product is then fully ground to obtain the solid carbon-based base catalyst.

[0054] Specifically, the organic compound precursor containing carbon and nitrogen elements is any one of porphyrin, dopamine, melamine, dicyandiamide, and urea.

[0055] In the mixed reaction system, the mass of the solid carbon-based base catalyst is 2% to 30% of the mass of castor oil or ricinoleic acid alkyl ester; the molar ratio of castor oil or ricinoleic acid alkyl ester to bisulfite is 1:(1-6); and the mass ratio of castor oil or ricinoleic acid alkyl ester to low-carbon alcohol is 1:(2-5).

[0056] In one specific embodiment, the solvent is a combination of lower alcohol and water, and the mass ratio of the lower alcohol to water is 1:(1-5).

[0057] Wherein, the low-carbon alcohol is any one of ethanol, isopropanol, n-butanol, tert-butanol, and tri-pentanol.

[0058] The castor oil-based sulfonate anionic surfactant and its preparation method of the present invention will be described in detail below with reference to specific examples.

[0059] Example 1

[0060] 1) Preparation of solid carbon-based base catalyst: 5.0 g of melamine was accurately weighed and calcined in a muffle furnace at 650° C. for 4 h. The desired catalyst was obtained after grinding. Figure 1 This is the XRD pattern of the catalyst.

[0061] 2) Double bond addition sulfonation reaction:

[0062] Add 9.334g (0.01 mol) of castor oil to a 100mL beaker. Then, add 28.002g of isopropyl alcohol in a 1:3 ratio of castor oil to lower alcohol (mass ratio), stirring thoroughly to mix thoroughly. In a separate 250mL three-necked flask, add 6.244g (0.06 mol) of sodium bisulfite in a 1:6 ratio of castor oil to sodium bisulfite. Add 28.002g of deionized water (1:1 ratio of deionized water to isopropyl alcohol) to fully dissolve the sodium bisulfite. Add 0.467g of a carbon-based base catalyst (5% by mass in castor oil). Pour the castor oil and isopropyl alcohol mixture into the three-necked flask and stir at 40°C for 20 hours. After the reaction, the solid carbon-based catalyst was filtered out, and the isopropanol was removed by vacuum distillation. Subsequently, deionized water and petroleum ether were added to extract and remove the unreacted castor oil. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying to remove water, the castor oil sulfonic acid sodium salt anionic surfactant of the present invention was obtained, and the product yield was 95.60%.

[0063] in, Figure 2 The infrared spectrum of the castor oil sulfonic acid sodium salt anionic surfactant prepared in Example 1 is shown. It can be seen from the figure that the wave number is 3403 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2928 and 2855 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1741cm -1 The stretching vibration peak of the ester group -COOR is at 3008cm -1 The stretching vibration peak of the double bond -CH=CH- in castor oil is not shown in the figure, indicating that the double bond undergoes an addition reaction; and at wave numbers 1168 and 1041 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3Na appears at . It can be seen from this that the synthesized product is the target product, castor oil sulfonic acid sodium salt, that is, castor oil sulfonic acid sodium salt anionic surfactant of the present invention.

[0064] The material structure and NMR characterization data of the castor oil sulfonic acid sodium salt anionic surfactant prepared in Example 1 are as follows:

[0065]

[0066] 1H NMR (400MHz, DMSO-d6) δ4.87 (s, 1H), 4.11 (d, J = 5.6Hz, 4H), 3.53–3.43 (m, 3H ),3.22(d,J=6.7Hz,3H),2.90–2.79(m,3H),2.31(dt,J=8.1,7.0Hz,6H),2.0 0–1.84(m,6H),1.84–1.68(m,6H),1.58–1.44(m,6H),1.48–1.36(m,12H),1. 41–1.31(m,6H),1.36–1.23(m,30H),1.28–1.20(m,12H),0.94–0.83(m,9H).

[0067]

[0068] 1 H NMR (400MHz, DMSO-d6) δ4.87(p,J=5.6Hz,1H),4.11(d,J=5.5Hz,4H),3.81–3.69(m,3H),2.89–2.73(m,6H),2.31(dt,J=8.1,7.0 Hz,6H),1.86–1.64(m,12H),1.61–1.48(m,12H),1.46–1.36(m,12H),1.41–1.33(m,6H),1.37–1.20(m,36H),0.95–0.83(m,9H).

[0069] in, Figure 3 The surface tension diagram of the sodium salt of castor oil sulfonate anionic surfactant prepared in Example 1 at different concentrations is shown. 1.0g of the sodium salt of castor oil sulfonate anionic surfactant prepared in Example 1 was weighed and prepared into a surfactant aqueous solution with a concentration of 1g / L. The instrument used in the test is a German KRUSS K100C surface tension tester, which tests the surface tension based on the Wilhelmy Plate method by using a platinum plate to contact the surface of an aqueous solution containing a certain concentration of surfactant. The test temperature is controlled to 25±0.5°C using a circulating water bath from Ulabo Technology. When the instrument starts the test, it first measures the surface tension of pure water, and continuously injects an equal volume of surfactant solution into the test container while keeping the volume of the measured solution constant, and accurately extracts the corresponding volume of solution, so that the concentration of the surfactant solution continuously changes from dilute to concentrated, and the surface tension of the solution at different concentrations can be obtained. At the end of the test, a curve of the relationship between surface tension and concentration can be obtained (such as Figure 2 As shown). Figure 2It can be determined that the critical micelle concentration (CMC) of the surfactant is 4.50 mmol / L and the corresponding surface tension (γ CMC ) is 43.45 mN / m, which shows that the castor oil sulfonic acid sodium salt anionic surfactant prepared in Example 1 has typical surfactant properties and can effectively reduce the surface tension of the aqueous solution.

[0070] in, Figure 4 The foam micromorphology of the castor oil sulfonic acid sodium salt anionic surfactant prepared in Example 1 at a concentration of 1.0 g / L is shown. 1.0 g of the castor oil sulfonic acid sodium salt anionic surfactant prepared in Example 1 was weighed and prepared into an aqueous surfactant solution with a concentration of 1 g / L. The instrument used for the test was a German KRUSSDFA100 dynamic foam analyzer, and the test temperature was controlled to be 25±0.5°C. 50 mL of the prepared solution was placed in a 250 mm cylindrical glass column and mechanically stirred at a speed of 6000 r / min for 30 seconds to generate foam, with a total running time of 1200 seconds. From the analysis of the foam micromorphology by the dynamic foam analyzer, it can be seen that the castor oil sulfonic acid sodium salt anionic surfactant prepared in Example 1 has a small initial foaming amount and the foam is relatively fine and stable.

[0071] Example 2

[0072] 1) Preparation of solid carbon-based base catalyst: 5.0 g of melamine was accurately weighed and calcined in a muffle furnace at 550° C. for 5 h. The desired catalyst was obtained after grinding.

[0073] 2) Double bond addition sulfonation reaction:

[0074] Add 9.334g (0.01mol) of castor oil to a 100mL beaker, then add 46.670g of n-butanol in a castor oil:lower alcohol ratio of 1:5 (mass ratio) and stir thoroughly to mix thoroughly. In a separate 250mL three-necked flask, add 6.008g (0.05mol) of potassium bisulfite in a castor oil:potassium bisulfite ratio of 1:5 (mass ratio). Add 93.340g of deionized water in a 1:2 mass ratio of deionized water to n-butanol to fully dissolve the potassium bisulfite. Then, add 1.400g of a carbon-based base catalyst (15% mass fraction in castor oil). Pour the castor oil and n-butanol mixture into the three-necked flask and stir at 40°C for 20 hours. After the reaction, the solid carbon-based catalyst was filtered out, and the n-butanol was removed by vacuum distillation. Subsequently, deionized water and petroleum ether were added to extract and remove unreacted castor oil. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying to remove water, the castor oil sulfonic acid potassium salt anionic surfactant of the present invention was obtained, and the product yield was 90.23%.

[0075] Using the detection method described in Example 1, it can be seen from the infrared spectrum of the castor oil sulfonic acid potassium salt anionic surfactant that the wave number is 3403cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2929 and 2856 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1741cm -1 The stretching vibration peak of the ester group -COOR is located at 3008 cm -1 The stretching vibration peak of the double bond -CH=CH- at 1169 cm-1 and 1044 cm-1 indicates that the double bond undergoes an addition reaction. -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3K appears at 370°C. Therefore, it can be known that the synthesized product is the target product castor oil sulfonate potassium salt, that is, castor oil sulfonate potassium salt anionic surfactant of the present invention.

[0076] The material structure and NMR characterization data of the castor oil sulfonate potassium salt anionic surfactant prepared in Example 2 are as follows:

[0077]

[0078] 1 H NMR (400MHz, DMSO-d6) δ4.87 (s, 1H), 4.11 (d, J = 5.6Hz, 4H), 3.53–3.43 (m, 3H ),3.22(d,J=6.7Hz,3H),2.90–2.79(m,3H),2.31(dt,J=8.1,7.0Hz,6H),2.0 0–1.84(m,6H),1.84–1.68(m,6H),1.58–1.44(m,18H),1.48–1.36(m,6H),1. 41–1.31(m,6H),1.36–1.23(m,24H),1.28–1.20(m,12H),0.94–0.83(m,9H).

[0079]

[0080] 1H NMR (400MHz, DMSO-d6) δ4.87(p,J=5.6Hz,1H),4.11(d,J=5.5Hz,4H),3.81–3.69(m,3H),2.89–2.77(m,6H),2.31(dt,J=8.1,7. 0Hz,6H),1.85–1.64(m,12H),1.61–1.48(m,24H),1.51–1.36(m,6H),1.41–1.33(m,6H),1.37–1.20(m,30H),0.95–0.83(m,9H).

[0081] The critical micelle concentration (CMC) of the surfactant was determined to be 4.55 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC ) was 43.47 mN / m, indicating that the castor oil sulfonate potassium salt anionic surfactant prepared in Example 2 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer revealed that the castor oil sulfonate potassium salt anionic surfactant prepared in Example 2 had an initial foaming volume of 113 mL, indicating a relatively fine and stable foam.

[0082] Example 3

[0083] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 16.020 g (0.50 mol) of methanol was added at a molar ratio of ricinoleic acid to fatty alcohol of 1:5. 0.951 g of p-toluenesulfonic acid was added as a catalyst based on 2.0% of the mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 60° C. with stirring, and the reaction was allowed to react for 7 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain methyl ricinoleate. The purity of the product was determined by gas chromatography to be 96.80%, the yield was 94.30%, and the molecular weight of the product was determined by mass spectrometry to be 312.49.

[0084] 2) Preparation of solid carbon-based base catalyst: 5.0 g of melamine was accurately weighed and calcined in a muffle furnace at 550° C. for 4 h. The desired catalyst was obtained after grinding.

[0085] 3) Double Bond Addition Sulfonation: Add 10.937 g (0.035 mol) of methyl ricinoleate to a 100 mL beaker. Then, add 54.686 g of isopropyl alcohol (at a mass ratio of 1:5) and stir thoroughly to mix thoroughly. In a separate 250 mL three-necked flask, add 10.926 g (0.105 mol) of sodium bisulfite (at a molar ratio of 1:3) of methyl ricinoleate to sodium bisulfite. Add 54.686 g of deionized water (at a mass ratio of 1:1) to fully dissolve the sodium bisulfite. Then, add 1.094 g of a solid carbon-based base catalyst (10% by mass based on methyl ricinoleate). Pour the mixed solution of methyl ricinoleate and isopropyl alcohol into the three-necked flask and stir at 40°C for 20 h. After the reaction, the solid carbon-based base catalyst was filtered out, and the isopropanol was removed by vacuum distillation. Subsequently, deionized water and petroleum ether were added to extract and remove unreacted methyl ricinoleate. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying and water removal steps, the sodium salt of methyl ricinoleate sulfonate anionic surfactant of the present invention was obtained, and the product yield was 75.68%.

[0086] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid methyl ester sulfonic acid sodium salt obtained in this example: wave number 3405 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2927 and 2855 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1735cm -1 The stretching vibration peak of the ester group -COOR is at 3008cm -1 The stretching vibration peak of the double bond -CH=CH- in ricinoleic acid methyl ester does not appear in the infrared spectrum of the product, indicating that the double bond undergoes an addition reaction; and at wave numbers 1171 and 1037 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3Na appears at . It can be seen from this that the synthesized product is the target product, methyl ricinoleate sulfonic acid sodium salt, that is, methyl ricinoleate sulfonic acid sodium salt anionic surfactant of the present invention.

[0087] The material structure and NMR characterization data of the ricinoleic acid methyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 3 are as follows:

[0088]

[0089] 1H NMR (400MHz, DMSO-d6) δ3.60(s,3H),3.48(dtd,J=12.9,6.9,6.0Hz,1H),3.22(d,J=6.7Hz,1H),2.85(tt,J=6.4,5.5Hz,1H),2.29(t, J=7.0Hz,2H),1.93(t,J=6.6Hz,2H),1.85–1.68(m,2H),1.52–1.33(m,6H),1.37–1.27(m,6H),1.31–1.19(m,10H),0.95–0.82(m,3H).

[0090]

[0091] 1 H NMR (400MHz, DMSO-d6) δ3.81–3.69(m,1H),3.60(s,3H),3.17(d,J=6.7Hz,1H),2.82(p,J=5.5Hz,1H),2.29(t,J=7.0Hz,2H),1.86–1.76(m, 2H),1.80–1.64(m,2H),1.60–1.47(m,2H),1.52–1.41(m,6H),1.45–1 .34(m,2H),1.39–1.26(m,10H),1.31–1.19(m,2H),0.95–0.82(m,3H).

[0092] The critical micelle concentration (CMC) of the surfactant was determined to be 12.02 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC ) was 34.33 mN / m, indicating that the ricinoleic acid methyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 3 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer shows that the ricinoleic acid methyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 3 has an initial foaming volume of 50 mL, and the foam is relatively fine and stable.

[0093] Example 4

[0094] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 23.035 g (0.50 mol) of ethanol was added at a molar ratio of ricinoleic acid to fatty alcohol of 1:5. 1.493 g of p-toluenesulfonic acid was added as a catalyst based on 5.0% of the mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 80° C. with stirring, and the reaction was allowed to react for 9 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain methyl ricinoleate. The purity of the product was 93.90% and the yield was 92.00% as measured by gas chromatography. The molecular weight of the product was 326.52 as measured by mass spectrometry.

[0095] 2) Preparation of solid carbon-based base catalyst: 5.0 g of urea was accurately weighed and calcined in a muffle furnace at 600° C. for 5 h. The desired catalyst was obtained after grinding.

[0096] 3) Double Bond Addition Sulfonation: Add 11.428g (0.035mol) of ethyl ricinoleate to a 100mL beaker. Then, add 52.553g of isopropyl alcohol at a mass ratio of 1:5 ethyl ricinoleate to lower alcohol and stir thoroughly to mix thoroughly. In a separate 250mL three-necked flask, add 14.568g (0.140mol) of sodium bisulfite at a mass ratio of 1:4 ethyl ricinoleate to sodium bisulfite. Add 52.553g of deionized water at a mass ratio of 1:1 deionized water to isopropyl alcohol to fully dissolve the sodium bisulfite. Then, add 2.286g of a solid carbon-based base catalyst (20% by mass in ethyl ricinoleate). Pour the mixed solution of ethyl ricinoleate and isopropyl alcohol into the three-necked flask and stir at 40°C for 20 hours. After the reaction, the solid carbon-based base catalyst was filtered out, and the isopropanol was removed by vacuum distillation. Subsequently, deionized water and petroleum ether were added to extract and remove unreacted ricinoleic acid ethyl ester. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying and water removal steps, the ricinoleic acid ethyl ester sulfonic acid sodium salt anionic surfactant of the present invention was obtained, and the product yield was 76.53%.

[0097] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid ethyl ester sulfonic acid sodium salt obtained in this example: wave number 3405 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2928 and 2856 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1734cm -1 The stretching vibration peak of the ester group -COOR is at 3007cm -1The stretching vibration peak of the double bond -CH=CH- in ricinoleic acid ethyl ester does not appear in the infrared spectrum of the product, indicating that the double bond undergoes an addition reaction; and the peaks at wave numbers 1172 and 1036 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3Na appears at . It can be seen from this that the synthesized product is the target product ricinoleic acid ethyl ester sulfonate sodium salt, that is, ricinoleic acid ethyl ester sulfonate sodium salt anionic surfactant of the present invention.

[0098] The material structure and NMR characterization data of the ricinoleic acid ethyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 4 are as follows:

[0099]

[0100] 1 H NMR (400MHz, DMSO-d6) δ4.17 (qt, J=6.8, 3.4Hz, 2H), 3.76 (d, J=6.6Hz, 1H), 3.48(dtd,J=12.8,6.8,5.9Hz,1H),2.85(tt,J=6.4,5.5Hz,1H),2.27(t,J= 7.0Hz,2H),1.93(t,J=6.6Hz,2H),1.85–1.68(m,2H),1.58–1.44(m,2H),1. 47–1.35(m,4H),1.39–1.31(m,2H),1.36–1.19(m,17H),0.95–0.82(m,3H).

[0101]

[0102] 1 H NMR (400MHz, DMSO-d6) δ4.17(qt,J=6.8,3.4Hz,2H),3.75(dp,J=6.8,6.0Hz,1H),3.34(d,J=6.7Hz,1H),2.82(p,J=5.5Hz,1H),2. 27(t,J=7.0Hz,2H),1.86–1.76(m,2H),1.80–1.64(m,2H),1.60–1.34(m,4H),1.39–1.23(m,18H),1.25(s,3H),0.95–0.82(m,3H).

[0103] The critical micelle concentration (CMC) of the surfactant was determined to be 10.70 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC) was 33.48 mN / m, indicating that the ricinoleic acid ethyl ester sulfonate sodium salt anionic surfactant prepared in Example 4 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer shows that the ricinoleic acid ethyl ester sulfonate sodium salt anionic surfactant prepared in Example 4 has an initial foaming volume of 62 mL, and the foam is relatively fine and stable.

[0104] Example 5

[0105] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 37.061 g (0.50 mol) of n-butanol was added at a molar ratio of ricinoleic acid to fatty alcohol of 1:5. 2.985 g of p-toluenesulfonic acid was added as a catalyst based on 10.0% of the mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 90° C. with stirring, and the reaction was allowed to react for 8 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain butyl ricinoleate. The purity of the product was 90.81% and the yield was 91.34% as measured by gas chromatography. The molecular weight of the product was 354.57 as measured by mass spectrometry.

[0106] 2) Preparation of solid carbon-based base catalyst: 5.0 g of melamine was accurately weighed and calcined in a muffle furnace at 650° C. for 3 h. The desired catalyst was obtained after grinding.

[0107] 3) Double Bond Addition Sulfonation: Add 12.410 g (0.035 mol) of butyl ricinoleate to a 100 mL beaker. Then, add 52.553 g of tert-butyl alcohol (tert-butyl alcohol) at a mass ratio of 1:5 butyl ricinoleate to lower alcohol and stir thoroughly to mix thoroughly. In a separate 250 mL three-necked flask, add 21.853 g (0.210 mol) of sodium bisulfite at a mass ratio of 1:6 butyl ricinoleate to sodium bisulfite. Add 52.553 g of deionized water (1:1 mass ratio of deionized water to tert-butyl alcohol) to fully dissolve the sodium bisulfite. Then, add 1.862 g of a solid carbon-based base catalyst (15% mass fraction based on butyl ricinoleate). Pour the butyl ricinoleate and tert-butyl alcohol solution into the three-necked flask and stir at 40°C for 10 h. After the reaction, the solid carbon-based base catalyst was filtered out, and the tert-butanol was removed by vacuum distillation. Subsequently, deionized water and petroleum ether were added to extract and remove unreacted butyl ricinoleate. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying and water removal steps, the sodium salt of butyl ricinoleate sulfonate anionic surfactant of the present invention was obtained, and the product yield was 78.99%.

[0108] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid butyl ester sulfonic acid sodium salt obtained in this example: wave number 3404 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2927 and 2857 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1734cm -1 The stretching vibration peak of the ester group -COOR is at 3008cm -1 The stretching vibration peak of the double bond -CH=CH- in butyl ricinoleate is not present in the infrared spectrum of the product, indicating that an addition reaction occurs on the double bond. -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3Na appears at . It can be seen from this that the synthesized product is the target product, butyl ricinoleate sulfonic acid sodium salt, that is, butyl ricinoleate sulfonic acid sodium salt anionic surfactant of the present invention.

[0109] The material structure and NMR characterization data of the sodium salt of butyl ricinoleate sulfonate anionic surfactant prepared in Example 5 are as follows:

[0110]

[0111] 1 H NMR(400MHz,DMSO-d6)δ4.09(t,J=6.1Hz,2H),3.76(d,J=6.6Hz,1H),3.48(d td,J=12.7,6.8,5.9Hz,1H),2.85(tt,J=6.4,5.5Hz,1H),2.28(t,J=7.0Hz,2 H),1.93(t,J=6.6Hz,2H),1.85–1.68(m,2H),1.56(dp,J=31.8,6.7Hz,2H),1 .50–1.37(m,2H),1.42–1.27(m,10H),1.31–1.19(m,12H),0.95–0.82(m,6H).

[0112]

[0113] 1H NMR (400MHz, DMSO-d6) δ4.09(t,J=6.1Hz,2H),3.75(dp,J=6.9,6.0Hz,1H),3.34(d,J=6.7Hz,1H),2.82(p,J=5.5Hz,1H),2.28(t,J=7.0Hz,2H), 1.81(td,J=7.4,5.6Hz,2H),1.80–1.64(m,2H),1.65–1.43(m,6H),1.47 –1.32(m,4H),1.37–1.27(m,10H),1.31–1.19(m,6H),0.95–0.82(m,6H).

[0114] The critical micelle concentration (CMC) of the surfactant was determined to be 5.17 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC ) was 32.05 mN / m, indicating that the ricinoleic acid butyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 5 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer shows that the initial foaming volume of the ricinoleic acid butyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 5 is 81 mL, and the foam is relatively fine and stable.

[0115] Example 6

[0116] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 55.901 g (0.30 mol) of dodecanol was added according to a molar ratio of ricinoleic acid: fatty alcohol = 1:3. 0.951 g of p-toluenesulfonic acid as a catalyst was added according to 2.0% of the mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 90° C. with stirring, and the reaction was allowed to react for 6 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain ricinoleic acid dodecanol ester. The purity of the product was measured by gas chromatography to be 89.92%, the yield was 95.12%, and the molecular weight of the product was measured by mass spectrometry to be 466.79.

[0117] 2) Preparation of solid carbon-based base catalyst: 5.0 g of urea was accurately weighed and calcined in a muffle furnace at 550° C. for 5 h. The desired catalyst was obtained after grinding.

[0118] 3) Double Bond Addition Sulfonation Reaction: Add 14.004g (0.03 mol) of lauryl ricinoleate to a 100mL beaker. Then, add 42.011g of triamyl alcohol in a 1:3 mass ratio of lauryl ricinoleate to lower alcohol and stir thoroughly to mix thoroughly. In a separate 250mL three-necked flask, add 3.1218g (0.03 mol) of sodium bisulfite in a 1:1 mass ratio of lauryl ricinoleate to sodium bisulfite. Add 84.022g of deionized water in a 1:2 mass ratio of deionized water to triamyl alcohol to fully dissolve the sodium bisulfite. Then, add 3.501g of a solid carbon-based base catalyst (25% mass fraction based on lauryl ricinoleate). Pour the mixed solution of lauryl ricinoleate and triamyl alcohol into the three-necked flask and stir at 50°C for 12 hours. After the reaction, the solid carbon-based base catalyst was filtered out, and tri-amyl alcohol was removed by vacuum distillation. Subsequently, deionized water and petroleum ether were added to extract and remove unreacted ricinoleic acid lauryl ester. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying and water removal steps, the ricinoleic acid lauryl ester sulfonic acid sodium salt anionic surfactant of the present invention was obtained, and the product yield was 77.01%.

[0119] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid lauryl ester sulfonic acid sodium salt obtained in this example: wave number 3406 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2928 and 2855 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1739cm -1 The stretching vibration peak of the ester group -COOR is at 3010cm -1 The stretching vibration peak of the double bond -CH=CH- in ricinoleic acid lauryl ester does not appear in the infrared spectrum of the product, indicating that the double bond undergoes an addition reaction; and the peaks at wave numbers 1174 and 1036 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3Na appears at . It can be seen from this that the synthesized product is the target product, ricinoleic acid lauryl ester sulfonic acid sodium salt, that is, ricinoleic acid lauryl ester sulfonic acid sodium salt anionic surfactant of the present invention.

[0120] The material structure and NMR characterization data of the sodium salt of lauryl ricinoleate sulfonate anionic surfactant prepared in Example 6 are as follows:

[0121]

[0122] 1H NMR (400MHz, DMSO-d6) δ4.02(td,J=6.0,1.0Hz,2H),3.52–3.44(m,1H),3.29(d,J=6.6Hz,1H),2.85(tt,J=6.5,5.5Hz,1H),2.28(t,J=7 .0Hz,2H),1.93(hept,J=6.3Hz,2H),1.76(ddd,J=12.0,6.3,5.3Hz,2H),1.52(p,J=6.9Hz,2H),1.49–1.19(m,40H),0.95–0.82(m,6H).

[0123]

[0124] 1 H NMR(400MHz, DMSO-d6)δ4.02(td,J=6.0,1.0Hz,2H),3.75(dt,J=6.7,6.0Hz,1H),2.94–2.77(m,2H), 2.28(t,J=7.0Hz,2H),1.84–1.65(m,4H),1.60–1.48(m,4H),1.51–1.19(m,38H),0.95–0.82(m,6H).

[0125] The critical micelle concentration (CMC) of the surfactant was determined to be 1.51 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC ) was 30.57 mN / m, indicating that the sodium salt of ricinoleic acid lauryl ester sulfonate anionic surfactant prepared in Example 6 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer showed that the sodium salt of ricinoleic acid lauryl ester sulfonate anionic surfactant prepared in Example 6 had an initial foaming volume of 126 mL, and the foam was relatively fine and stable.

[0126] Example 7

[0127] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 78.138 g (0.30 mol) of n-octanol was added according to a molar ratio of ricinoleic acid to fatty alcohol of 1:6. 1.791 g of p-toluenesulfonic acid as a catalyst was added according to 6.0% of the mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 80° C. with stirring, and the reaction was allowed to react for 5 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain ricinoleic acid octanol ester. The purity of the product was measured by gas chromatography to be 92.13%, the yield was 93.11%, and the molecular weight of the product was measured by mass spectrometry to be 410.72.

[0128] 2) Preparation of solid carbon-based base catalyst: 5.0 g of dopamine was accurately weighed and calcined in a muffle furnace at 550° C. for 7 h. The desired catalyst was obtained after grinding.

[0129] 3) Double Bond Addition Sulfonation: Add 12.322g (0.03 mol) of octanol ricinoleate to a 100mL beaker. Then, add 42.011g of ethanol in a 1:3 (mass ratio) of octanol ricinoleate to lower alcohol and stir thoroughly to mix thoroughly. In a separate three-necked flask, add 3.602g (0.03 mol) of potassium bisulfite in a 1:1 (molar ratio) of octanol ricinoleate to potassium bisulfite. Add 84.022g of deionized water in a 1:2 (mass ratio) of deionized water to ethanol to fully dissolve the potassium bisulfite. Then, add 3.697g of a solid carbon-based base catalyst (30% by mass in octanol ricinoleate). Pour the octanol ricinoleate-ethanol mixture into the three-necked flask and stir at 50°C for 12 hours. After the reaction is completed, the solid carbon-based base catalyst is filtered out, and ethanol is removed by vacuum distillation. Subsequently, deionized water and petroleum ether are added to extract and remove unreacted ricinoleic acid octanol ester. Ethanol is added to the aqueous phase and stirred for 0.5 h. The mixture is sealed and allowed to stand overnight. The precipitated inorganic salts are removed by suction filtration. After vacuum distillation and drying and water removal steps, the ricinoleic acid octanol ester sulfonate potassium salt anionic surfactant of the present invention is obtained, and the product yield is 82.01%.

[0130] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid octanol ester sulfonic acid potassium salt obtained in this example: wave number 3405 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2928 and 2855 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1739cm -1 The stretching vibration peak of the ester group -COOR is at 3009cm -1The stretching vibration peak of the double bond -CH=CH- in ricinoleic acid octanol ester does not appear in the infrared spectrum of the product, indicating that the double bond undergoes an addition reaction; and the peaks at wave numbers 1172 and 1035 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3K appears at . It can be seen from this that the synthesized product is the target product ricinoleic acid octanol ester sulfonate potassium salt, that is, ricinoleic acid octanol ester sulfonate potassium salt anionic surfactant of the present invention.

[0131] The material structure and NMR characterization data of the potassium salt of octanol sulfonic acid ricinoleate anionic surfactant prepared in Example 7 are as follows:

[0132]

[0133] 1 H NMR (400MHz, DMSO-d6) δ4.02(t,J=5.8Hz,2H),3.48(dtd,J=12.9,6.9,6.0Hz,1H),3.29(d,J=6.6Hz,1H),2.90–2.79(m,1H),2.28(t,J= 7.0Hz,2H),1.93(hept,J=6.3Hz,2H),1.76(ddd,J=12.0,6.2,5.2Hz,2H),1.52(p,J=6.9Hz,2H),1.48–1.19(m,32H),0.95–0.82(m,6H).

[0134]

[0135] 1 H NMR(400MHz, DMSO-d6)δ4.02(t,J=5.9Hz,2H),3.75(dt,J=6.8,6.0Hz,1H),2.94–2.77(m,2H),2. 28(t,J=7.0Hz,2H),1.86–1.65(m,4H),1.60–1.46(m,4H),1.50–1.19(m,30H),0.95–0.82(m,6H).

[0136] The critical micelle concentration (CMC) of the surfactant was determined to be 1.72 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC) was 31.39 mN / m, indicating that the ricinoleic acid octanol ester sulfonate potassium salt anionic surfactant prepared in Example 7 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer shows that the ricinoleic acid octanol ester sulfonate potassium salt anionic surfactant prepared in Example 7 has an initial foaming capacity of 108 mL, and the foam is relatively fine and stable.

[0137] Example 8

[0138] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 30.653 g (0.30 mol) of hexanol was added according to a molar ratio of ricinoleic acid: fatty alcohol = 1:3. 1.492 g of p-toluenesulfonic acid was added as a catalyst according to 5.0% of the mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 80° C. with stirring, and the reaction was allowed to react for 5 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain ricinoleic acid hexanol ester. The purity of the product was measured by gas chromatography to be 90.21%, the yield was 89.73%, and the molecular weight of the product was measured by mass spectrometry to be 382.72.

[0139] 2) Preparation of solid carbon-based base catalyst: 5.0 g of porphyrin was accurately weighed and calcined in a muffle furnace at 500° C. for 5 h. The desired catalyst was obtained after grinding.

[0140] 3) Double Bond Addition Sulfonation Reaction: Add 12.322 g (0.03 mol) of ricinoleic acid hexyl ester to a 100 mL beaker. Then, add 42.011 g of ethanol in a 1:3 (mass ratio) of ricinoleic acid hexyl ester to lower alcohol and stir thoroughly to mix thoroughly. In a separate 250 mL three-necked flask, add 3.602 g (0.03 mol) of potassium bisulfite in a 1:1 (molar ratio) of ricinoleic acid hexyl ester to potassium bisulfite. Then, add 126.003 g of deionized water in a 1:3 (mass ratio) of deionized water to ethanol to fully dissolve the potassium bisulfite. Then, add 3.697 g of a solid carbon-based base catalyst (30% by mass in ricinoleic acid hexyl ester). Pour the mixed solution of ricinoleic acid hexyl ester and ethanol into the three-necked flask and stir at 50°C for 12 h. After the reaction, the solid carbon-based base catalyst was filtered out, and ethanol was removed by vacuum distillation. Subsequently, deionized water and petroleum ether were added to extract and remove unreacted ricinoleic acid hexanol ester. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying and water removal steps, the ricinoleic acid hexanol ester sulfonic acid potassium salt anionic surfactant of the present invention was obtained, and the product yield was 89.21%.

[0141] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid hexyl ester sulfonic acid potassium salt obtained in this example: wave number 3403 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2927 and 2856 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1737cm -1 The stretching vibration peak of the ester group -COOR is at 3009cm -1 The stretching vibration peak of the double bond -CH=CH- in ricinoleic acid octanol ester does not appear in the infrared spectrum of the product, indicating that the double bond undergoes an addition reaction; and the peaks at wave numbers 1172 and 1035 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3K appears at . It can be seen from this that the synthesized product is the target product, ricinoleic acid hexanol ester sulfonate potassium salt, that is, ricinoleic acid hexanol ester sulfonate potassium salt anionic surfactant of the present invention.

[0142] The material structure and NMR characterization data of the potassium salt of ricinoleate sulfonate anionic surfactant prepared in Example 8 are as follows:

[0143]

[0144] 1 H NMR (400MHz, DMSO-d6) δ4.02(t,J=6.1Hz,2H),3.76(d,J=6.6Hz,1H),3.48(dtd,J=12.8,6.8,6 .0Hz,1H),2.85(tt,J=6.4,5.5Hz,1H),2.28(t,J=7.0Hz,2H),1.92(td,J=6.6,3.3Hz,2H),1.8 3–1.69(m,2H),1.63(p,J=6.4Hz,2H),1.58–1.44(m,2H),1.47–1.41(m,2H),1.45–1.34(m,4H) ,1.38–1.29(m,10H),1.34–1.28(m,4H),1.27(qdd,J=6.8,4.1,1.9Hz,6H),0.95–0.82(m,6H).

[0145]

[0146] 1H NMR (400MHz, DMSO-d6) δ4.02(t,J=6.1Hz,2H),3.81–3.69(m,1H),3.35(d,J=6.6Hz,1H),2.82(p,J=5.5Hz,1H),2.28(t,J=7.0Hz,2H), 1.84–1.67(m,4H),1.71–1.59(m,2H),1.62–1.47(m,4H),1.51–1.39(m,6H),1.43–1.31(m,8H),1.35–1.19(m,10H),0.95–0.82(m,6H).

[0147] The critical micelle concentration (CMC) of the surfactant was determined to be 1.81 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC ) was 31.83 mN / m, indicating that the ricinoleic acid hexanol ester sulfonate potassium salt anionic surfactant prepared in Example 8 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer shows that the initial foaming volume of the ricinoleic acid hexanol ester sulfonate potassium salt anionic surfactant prepared in Example 8 is 96 mL, and the foam is relatively fine and stable.

[0148] Example 9

[0149] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 40.075 g (0.50 mol) of amyl alcohol was added according to a molar ratio of ricinoleic acid: fatty alcohol = 1:5. 1.492 g of p-toluenesulfonic acid as a catalyst was added according to 5.0% of the mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 60° C. with stirring, and the reaction was allowed to react for 5 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain amyl ricinoleate. The purity of the product was measured by gas chromatography to be 96.12%, the yield was 90.24%, and the molecular weight of the product was measured by mass spectrometry to be 368.72.

[0150] 2) Preparation of solid carbon-based base catalyst: 5.0 g of porphyrin was accurately weighed and calcined in a muffle furnace at 600° C. for 6 h. The desired catalyst was obtained after grinding.

[0151] 3) Double Bond Addition Sulfonation: Add 11.062g (0.03 mol) of amyl ricinoleate to a 100mL beaker. Then, add 33.185g of ethanol in a 1:3 (mass ratio) of amyl ricinoleate to lower alcohol and stir thoroughly to mix thoroughly. In a separate 250mL three-necked flask, add 18.009g (0.15 mol) of potassium bisulfite in a 1:5 (molar ratio) of amyl ricinoleate to potassium bisulfite. Add 33.185g of deionized water in a 1:1 (mass ratio) of deionized water to ethanol to fully dissolve the potassium bisulfite. Then, add 1.659g of a solid carbon-based base catalyst (15% by mass in amyl ricinoleate). Pour the mixed solution of amyl ricinoleate and ethanol into the three-necked flask and stir at 60°C for 12 hours. After the reaction is completed, the solid carbon-based base catalyst is filtered out, and ethanol is removed by vacuum distillation. Subsequently, deionized water and petroleum ether are added to extract and remove unreacted ricinoleic acid amyl ester. Ethanol is added to the aqueous phase and stirred for 0.5 h. The mixture is sealed and allowed to stand overnight. The precipitated inorganic salts are removed by suction filtration. After vacuum distillation and drying and water removal steps, the ricinoleic acid amyl ester sulfonate potassium salt anionic surfactant of the present invention is obtained, and the product yield is 92.54%.

[0152] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid amyl ester sulfonic acid potassium salt obtained in this example: wave number 3404 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2927 and 2856 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1737cm -1 The stretching vibration peak of the ester group -COOR is at 3009cm -1 The stretching vibration peak of the double bond -CH=CH- in ricinoleic acid octanol ester does not appear in the infrared spectrum of the product, indicating that the double bond undergoes an addition reaction; and the peaks at wave numbers 1172 and 1035 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3K appears at . It can be seen from this that the synthesized product is the target product, ricinoleic acid amyl alcohol ester sulfonate potassium salt, that is, ricinoleic acid amyl alcohol ester sulfonate potassium salt anionic surfactant of the present invention.

[0153] The material structure and NMR characterization data of the potassium salt of ricinoleate sulfonate anionic surfactant prepared in Example 9 are as follows:

[0154]

[0155] 1H NMR (400MHz, DMSO-d6) δ4.04(t,J=6.1Hz,2H),3.76(d,J=6.6Hz,1H),3.48(dtd,J=12.7,6.8,5.9Hz,1H),2.85(tt,J=6.4,5.5Hz,1H),2.28(t,J=7.0H z,2H),1.93(t,J=6.6Hz,2H),1.85–1.61(m,4H),1.52(p,J=6.9Hz,2H),1.4 9–1.41(m,4H),1.45–1.30(m,10H),1.35–1.19(m,10H),0.95–0.81(m,6H).

[0156]

[0157] 1 H NMR (400MHz, DMSO-d6) δ4.04(t,J=6.1Hz,2H),3.81–3.69(m,1H),3.35(d,J=6.6Hz,1H),2.82(p,J=5.5Hz,1H),2.28(t,J=7. 0Hz,2H),1.86–1.61(m,6H),1.59–1.38(m,8H),1.42–1.33(m,4H),1.37–1.26(m,4H),1.30–1.19(m,10H),0.95–0.81(m,6H).

[0158] The critical micelle concentration (CMC) of the surfactant was determined to be 1.85 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC ) was 32.98 mN / m, indicating that the potassium ricinoleate sulfonate anionic surfactant prepared in Example 9 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer revealed that the initial foaming volume of the potassium ricinoleate sulfonate anionic surfactant prepared in Example 9 was 86 mL, and the foam was relatively fine and stable.

[0159] Example 10

[0160] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 94.968 g (0.60 mol) of decanol was added according to a molar ratio of ricinoleic acid: fatty alcohol = 1:6. 2.089 g of p-toluenesulfonic acid as a catalyst was added according to 7.0% of the mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 65° C. with stirring, and the reaction was allowed to react for 4 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain decanol ricinoleate. The purity of the product was measured by gas chromatography to be 93.13%, the yield was 97.12%, and the molecular weight of the product was measured by mass spectrometry to be 438.74.

[0161] 2) Preparation of solid carbon-based base catalyst: 5.0 g of porphyrin was accurately weighed and calcined in a muffle furnace at 600° C. for 6 h. The desired catalyst was obtained after grinding.

[0162] 3) Double Bond Addition Sulfonation Reaction: Add 13.162g (0.03 mol) of ricinoleic acid decyl ester to a 100mL beaker. Then, add 65.810g of tert-butyl alcohol in a 1:5 (mass ratio) of ricinoleic acid decyl ester to lower alcohol and stir thoroughly to mix thoroughly. In a separate 250mL three-necked flask, add 3.1218g (0.03 mol) of sodium bisulfite in a 1:1 (molar ratio) of ricinoleic acid decyl ester to sodium bisulfite. Add 131.62g of deionized water in a 1:2 (mass ratio) of deionized water to tert-butyl alcohol to fully dissolve the sodium bisulfite. Then, add 1.316g of a solid carbon-based base catalyst (10% by mass in ricinoleic acid decyl ester). Pour the mixed solution of ricinoleic acid decyl ester and tert-butyl alcohol into the three-necked flask and stir at 40°C for 10 hours. After the reaction, the solid carbon-based base catalyst was filtered out, and the tert-butanol was removed by vacuum distillation. Subsequently, deionized water and petroleum ether were added to extract and remove unreacted decyl ricinoleate. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying and water removal steps, the sodium salt of decyl ricinoleate sulfonate anionic surfactant of the present invention was obtained, and the product yield was 87.91%.

[0163] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid decyl ester sulfonic acid sodium salt obtained in this example: wave number 3406 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2928 and 2855 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1739cm -1 The stretching vibration peak of the ester group -COOR is at 3010cm -1The stretching vibration peak of the double bond -CH=CH- in ricinoleic acid decyl ester does not appear in the infrared spectrum of the product, indicating that the double bond undergoes an addition reaction; and the peaks at wave numbers 1172 and 1035 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3Na appears at . It can be seen from this that the synthesized product is the target product ricinoleic acid decyl ester sulfonate potassium salt, that is, ricinoleic acid decyl ester sulfonate sodium salt anionic surfactant of the present invention.

[0164] The material structure and NMR characterization data of the sodium decyl ricinoleate sulfonate anionic surfactant prepared in Example 10 are as follows:

[0165]

[0166] 1 H NMR (400MHz, DMSO-d6) δ4.02(t,J=5.8Hz,2H),3.48(dtd,J=12.9,6.9,6.0Hz,1H),3.29(d,J=6.6Hz,1H),2.88–2.81(m,1H),2.28(t,J= 7.0Hz,2H),1.93(hept,J=6.3Hz,2H),1.76(ddd,J=11.9,6.2,5.2Hz,2H),1.52(p,J=6.9Hz,2H),1.49–1.19(m,36H),0.95–0.82(m,6H).

[0167]

[0168] 1 H NMR(400MHz, DMSO-d6)δ4.02(t,J=6.0Hz,2H),3.81–3.69(m,1H),2.94–2.77(m,2H),2.28(t,J=7.0Hz,2H),1.8 4–1.65(m,4H),1.60–1.48(m,4H),1.51–1.36(m,6H),1.40–1.29(m,6H),1.33–1.19(m,22H),0.95–0.82(m,6H).

[0169] The critical micelle concentration (CMC) of the surfactant was determined to be 1.74 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC) was 32.73 mN / m, indicating that the ricinoleic acid decyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 10 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer shows that the initial foaming volume of the ricinoleic acid decyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 10 was 116 mL, and the foam was relatively fine and stable.

[0170] Example 11

[0171] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 18.428 g (0.40 mol) of ethanol was added at a molar ratio of ricinoleic acid to fatty alcohol of 1:4. 0.895 g of p-toluenesulfonic acid was added as a catalyst based on 3.0% of the mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 75° C. with stirring, and the reaction was allowed to react for 6 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain ethyl ricinoleate. The purity of the product was 96.57% and the yield was 94.56% as measured by gas chromatography. The molecular weight of the product was 326.52 as measured by mass spectrometry.

[0172] 2) Preparation of solid carbon-based base catalyst: 5.0 g of melamine was accurately weighed and calcined in a muffle furnace at 550° C. for 6 h. The desired catalyst was obtained after grinding.

[0173] 3) Double Bond Addition Sulfonation: Add 11.428g (0.035mol) of ethyl ricinoleate to a 100mL beaker. Then, add 45.712g of isopropyl alcohol in a 1:4 (mass ratio) of ethyl ricinoleate to lower alcohol and stir thoroughly to mix thoroughly. In a separate 250mL three-necked flask, add 16.808g (0.140mol) of potassium bisulfite in a 1:4 (mass ratio) of ethyl ricinoleate to potassium bisulfite. Then, add 45.712g of deionized water in a 1:1 (mass ratio) of deionized water to n-butanol to fully dissolve the sodium bisulfite. Then, add 1.714g of a solid carbon-based base catalyst (15% by mass in ethyl ricinoleate). Pour the mixed solution of ethyl ricinoleate and isopropyl alcohol into the three-necked flask and stir at 50°C for 24 hours. After the reaction, the solid carbon-based base catalyst was filtered out, and the isopropanol was removed by vacuum distillation. Deionized water and petroleum ether were added to extract and remove unreacted ricinoleic acid ethyl ester. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying and water removal steps, the ricinoleic acid ethyl ester sulfonate potassium salt anionic surfactant of the present invention was obtained, and the product yield was 87.93%.

[0174] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid ethyl ester sulfonic acid potassium salt obtained in this example: wave number 3405 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2928 and 2856 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1734cm -1 The stretching vibration peak of the ester group -COOR is at 3007cm -1 The stretching vibration peak of the double bond -CH=CH- in ricinoleic acid ethyl ester does not appear in the infrared spectrum of the product, indicating that the double bond undergoes an addition reaction; and the peaks at wave numbers 1172 and 1035 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3K appears at 370°C. Therefore, it can be known that the synthesized product is the target product ethyl ricinoleate sulfonate potassium salt, that is, the ethyl ricinoleate sulfonate potassium salt anionic surfactant of the present invention.

[0175] The material structure and NMR characterization data of the potassium salt of ethyl ricinoleate sulfonate anionic surfactant prepared in Example 11 are as follows:

[0176]

[0177] 1 H NMR (400MHz, DMSO-d6) δ4.17 (qt, J=6.8, 3.4Hz, 2H), 3.76 (d, J=6.6Hz, 1H), 3.48(dtd,J=12.7,6.8,5.9Hz,1H),2.85(tt,J=6.4,5.5Hz,1H),2.27(t,J=7 .0Hz,2H),1.93(t,J=6.6Hz,2H),1.85–1.68(m,2H),1.58–1.44(m,2H),1.4 7–1.27(m,6H),1.27(dddd,J=7.0,6.2,4.5,2.4Hz,17H),0.95–0.82(m,3H).

[0178]

[0179] 1H NMR (400MHz, DMSO-d6) δ4.17(qt,J=6.8,3.4Hz,2H),3.75(dp,J=6.8,6.0Hz,1H),3.34(d,J=6.7Hz,1H),2.82(p,J=5.5Hz,1H),2 .27(t,J=7.0Hz,2H),1.86–1.76(m,2H),1.80–1.64(m,2H),1.60–1.23(m,22H),1.25(s,3H),0.89(ddt,J=7.0,4.1,2.8Hz,3H).

[0180] The critical micelle concentration (CMC) of the surfactant was determined to be 10.89 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC ) was 33.45 mN / m, indicating that the ricinoleic acid ethyl ester sulfonate potassium salt anionic surfactant prepared in Example 4 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer shows that the ricinoleic acid ethyl ester sulfonate potassium salt anionic surfactant prepared in Example 4 has an initial foaming volume of 60 mL, and the foam is relatively fine and stable.

[0181] Example 12

[0182] 1) Esterification reaction: 29.846 g (0.10 mol) of ricinoleic acid was added to a three-necked round-bottom flask equipped with a magnetic stirrer, a condenser, and a nitrogen gas guide tube. 6.408 g (0.20 mol) of methanol was added at a molar ratio of ricinoleic acid to fatty alcohol of 1:2. 0.895 g of p-toluenesulfonic acid as a catalyst was added at a ratio of 3.0% by mass of ricinoleic acid. Under a nitrogen atmosphere, the temperature was raised to 70° C. with stirring, and the reaction was allowed to react for 10 h before being cooled to room temperature. The resulting reaction solution was extracted with ethyl acetate, washed with deionized water, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain methyl ricinoleate. The purity of the product was determined by gas chromatography to be 98.37%, the yield was 96.34%, and the molecular weight of the product was determined by mass spectrometry to be 312.49.

[0183] 2) Preparation of solid carbon-based base catalyst: 5.0 g of urea was accurately weighed and calcined in a muffle furnace at 550° C. for 4 h. The desired catalyst was obtained after grinding.

[0184] 3) Double Bond Addition Sulfonation: Add 10.937 g (0.035 mol) of methyl ricinoleate to a 100 mL beaker. Then, add 32.811 g of n-butanol in a 1:3 mass ratio of methyl ricinoleate to lower alcohol and stir thoroughly to mix thoroughly. In a separate 250 mL three-necked flask, add 14.568 g (0.140 mol) of sodium bisulfite in a 1:4 mass ratio of methyl ricinoleate to sodium bisulfite. Add 32.811 g of deionized water in a 1:1 mass ratio of deionized water to n-butanol to fully dissolve the sodium bisulfite. Then, add 1.641 g of a solid carbon-based base catalyst (15% mass fraction based on methyl ricinoleate). Pour the castor oil and isopropyl alcohol mixture into the three-necked flask and stir at 35°C for 24 hours. After the reaction, the solid carbon-based base catalyst was filtered out, and the n-butanol was removed by vacuum distillation. Subsequently, deionized water and petroleum ether were added to extract and remove unreacted methyl ricinoleate. Ethanol was added to the aqueous phase and stirred for 0.5 h. The mixture was sealed and allowed to stand overnight. The precipitated inorganic salts were removed by suction filtration. After vacuum distillation and drying and water removal steps, the sodium salt of methyl ricinoleate sulfonate anionic surfactant of the present invention was obtained, and the product yield was 79.72%.

[0185] The detection method described in Example 1 was used to obtain the IR (KBr) of the product ricinoleic acid methyl ester sulfonic acid sodium salt obtained in this example: wave number 3405 cm -1 The stretching vibration peaks of the hydroxyl group -OH are at wave numbers 2927 and 2855 cm -1 The stretching vibration peaks of methyl group -CH3 and methylene group -CH2- are at 1735cm -1 The stretching vibration peak of the ester group -COOR is at 3008cm -1 The stretching vibration peak of the double bond -CH=CH- in ricinoleic acid methyl ester does not appear in the infrared spectrum of the product, indicating that the double bond undergoes an addition reaction; and at wave numbers 1171 and 1037 cm -1 The characteristic stretching vibration peak of the sulfonic acid group -SO3Na appears at . It can be seen from this that the synthesized product is the target product, methyl ricinoleate sulfonic acid sodium salt, that is, methyl ricinoleate sulfonic acid sodium salt anionic surfactant of the present invention.

[0186] The material structure and NMR characterization data of the ricinoleic acid methyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 12 are as follows:

[0187]

[0188] 1H NMR (400MHz, DMSO-d6) δ3.60(s,3H),3.48(dtd,J=12.9,6.9,6.0Hz,1H),3.22(d,J=6.7Hz,1H),2.85(tt,J=6.4,5.5Hz,1H),2.29(t, J=7.0Hz,2H),1.93(t,J=6.6Hz,2H),1.85–1.68(m,2H),1.52–1.33(m,6H),1.37–1.27(m,6H),1.31–1.19(m,10H),0.95–0.82(m,3H).

[0189]

[0190] 1 H NMR (400MHz, DMSO-d6) δ3.81–3.69(m,1H),3.60(s,3H),3.17(d,J=6.7Hz,1H),2.82(p,J=5.5Hz,1H),2.29(t,J=7.0Hz,2H),1.86–1.76(m, 2H),1.80–1.64(m,2H),1.60–1.47(m,2H),1.52–1.41(m,6H),1.45–1 .34(m,2H),1.39–1.26(m,10H),1.31–1.19(m,2H),0.95–0.82(m,3H).

[0191] The critical micelle concentration (CMC) of the surfactant was determined to be 12.02 mmol / L by a static surface tension meter, and the corresponding surface tension (γ CMC ) was 34.33 mN / m, indicating that the ricinoleic acid methyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 12 has typical surfactant properties and can effectively reduce the surface tension of aqueous solutions. Analysis of the foam micromorphology using a dynamic foam analyzer shows that the ricinoleic acid methyl ester sulfonic acid sodium salt anionic surfactant prepared in Example 12 has an initial foaming volume of 50 mL, and the foam is relatively fine and stable.

[0192] In summary, the castor oil-based sulfonate anionic surfactant and its preparation method of the present invention have the following beneficial effects:

[0193] 1) Using castor oil or alkyl ricinoleate as raw materials, a castor oil-based sulfonic acid sodium salt anionic surfactant was synthesized by double bond addition sulfonation reaction catalyzed by a solid carbon-based base catalyst, realizing the resource utilization of castor oil.

[0194] 2) The solid carbon-based base catalyst exhibits excellent catalytic activity for the sulfonation reaction of bisulfite double bonds to synthesize castor oil-based sulfonates. No initiator or co-catalyst is required, and the conversion rate of the raw castor oil or alkyl ricinoleate can reach over 75%. Furthermore, the catalyst is simple to prepare, recyclable, and non-corrosive to equipment.

[0195] 3) The castor oil-based sulfonate anionic surfactant product of the present invention is derived from natural renewable oils and fats, can effectively reduce the surface tension of aqueous solutions, has good solubility, low foaming, fine foam, and excellent surfactant performance.

[0196] 4) The preparation method of the anionic surfactant of the present invention is simple to operate and easy to implement industrially.

[0197] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for preparing a castor oil-based sulfonate anionic surfactant, characterized in that: The following steps are involved: A mixed reaction system comprising a solid carbon-based base catalyst, a solvent, a bisulfite, and castor oil or a ricinoleic acid alkyl ester is subjected to a double bond addition sulfonation reaction to obtain a castor oil-based sulfonate anionic surfactant; Wherein, the ricinoleic acid alkyl ester has the following structural formula: , R is a C1~C12 alkyl group; The castor oil-based sulfonate anionic surfactant has any of the following structural formulas: ， ； wherein R is a C1-C12 alkyl group, R1 and R2 are each selected from H or sulfonate, and R1 and R2 are different; The solid carbon-based base catalyst is prepared by calcining an organic compound precursor containing carbon and nitrogen elements, and the organic compound precursor containing carbon and nitrogen elements is any one of porphyrin, dopamine, melamine, dicyandiamide, and urea; The double bond addition sulfonation reaction is carried out at a temperature of 30-80° C. and for a time of 10-100 h.

2. The method for preparing the castor oil-based sulfonate anionic surfactant according to claim 1, wherein: The castor oil-based sulfonate anionic surfactant has any of the following structural formulas: ， ， ， Wherein X is any one of K, Na, and NH4, and R is a C1~C12 alkyl group.

3. The method for preparing the castor oil-based sulfonate anionic surfactant according to claim 1, wherein: The mass of the solid carbon-based base catalyst is 2% to 30% of the mass of castor oil or ricinoleic acid alkyl ester; The molar ratio of castor oil or ricinoleic acid alkyl ester to bisulfite is 1:(1-6); The solvent includes a low-carbon alcohol, which is any one of ethanol, isopropanol, n-butanol, tert-butanol, and tri-amyl alcohol. The mass ratio of the castor oil or ricinoleic acid alkyl ester to the low-carbon alcohol is 1:(2~5).

4. The method for preparing the castor oil-based sulfonate anionic surfactant according to claim 1, wherein: The solvent is a combination of a low-carbon alcohol and water, the mass ratio of the low-carbon alcohol to water is 1:(1-5), and the low-carbon alcohol is any one of ethanol, isopropanol, n-butanol, tert-butanol, and tri-amyl alcohol.

Images