Green surfactant and preparation method thereof

Abstract

The invention discloses a green surfactant and a preparation method thereof, and belongs to the technical field of surfactants, the preparation method comprises the following steps: adding raw materials butenedioic acid ester and ammonium hydrogen sulfite and a catalyst nano H-Beta molecular sieve into a high-pressure reaction kettle, and introducing carbon dioxide for emptying; the temperature of the reaction kettle is set to be 50-70 DEG C, then carbon dioxide is introduced, the pressure of the reaction kettle is controlled to be 7-9 MPa, a reaction is carried out for 10-30 min, then filtering is carried out, and the obtained filtrate is the ammonium sulfosuccinate dialkyl ester surfactant. According to the preparation method, butenedioic acid ester and ammonium hydrogen sulfite are creatively adopted as raw materials, a nano H-Beta molecular sieve is adopted as a solid acid catalyst, supercritical carbon dioxide is adopted as a solvent, and the ammonium sulfosuccinate dialkyl ester surfactant is prepared through an addition reaction; a melting reaction technology and a supercritical ethanol crystallization reaction technology are introduced into the preparation of the nano H-Beta molecular sieve for the first time.

Description

Technical Field

[0001] The present invention belongs to the technical field of surfactants, and particularly relates to a green surfactant and a preparation method thereof. Background Art

[0002] Dialkyl sulfosuccinate ammonium surfactants are a type of green and environmentally friendly surfactants. Their molecular structures contain both ester groups and sulfonic acid groups, and they have good hydrophilicity and are widely used in industrial production such as fine chemicals, coatings, and pesticides. Currently, in the preparation methods of dialkyl sulfosuccinate ammonium surfactants, there are problems such as high reaction temperature, low yield, and long reaction time. Summary of the Invention

[0003] The purpose of the present invention is to provide a green surfactant and a preparation method thereof. The green surfactant provided by the present invention is a dialkyl sulfosuccinate ammonium surfactant, and the dialkyl sulfosuccinate ammonium surfactant prepared by the preparation method of the present invention has a high yield, a low reaction temperature, and a short reaction time.

[0004] The preparation method of the green surfactant of the present invention is as follows:

[0005] Step 1: Add the raw materials maleic acid ester, ammonium bisulfite, and nano H-Beta molecular sieve (as a catalyst) to a high-pressure reaction kettle, and introduce carbon dioxide for evacuation; in the above Step 1, the maleic acid ester is in a liquid state and is not easily soluble in water; ammonium bisulfite is a solid powder and is used in excess and can be removed by filtration.

[0006] Step 2: Set the temperature of the reaction kettle to 50 - 70 °C, then introduce carbon dioxide, and control the pressure of the reaction kettle at 7 - 9 MPa and react for 10 - 30 min, and then filter. The obtained filtrate is a dialkyl sulfosuccinate ammonium surfactant. The reaction equation is as follows:

[0007]

[0008] Among them, R is a straight-chain alkyl group with C3 - C12.

[0009] Further, in the above Step 1, the molar ratio of maleic acid ester to ammonium bisulfite is 1:(1.1 - 1.5); the dosage of nano H-Beta molecular sieve is 0.5 - 1.0% of the total mass of the raw materials.

[0010] Further, in the above Step 2, the molar ratio of the introduced carbon dioxide to maleic acid ester is (1.1 - 1.5):1.

[0011] Further, in the second step, during the reaction, the stirring rate is 400 - 600 r / min; after the reaction ends, it is cooled to room temperature, the pressure is released, and the nano H-Beta molecular sieve and excessive ammonium bisulfite are filtered off. The filtrate is the dialkyl ammonium sulfosuccinate surfactant.

[0012] Further, the preparation method of the nano H-Beta molecular sieve includes the following steps:

[0013] S1. Add tetraethyl orthosilicate as the silicon source, aluminum isopropoxide as the aluminum source, and N-octanoyl-N-butyldodecylammonium as the template agent into a stainless-steel autoclave; heat up to 115 - 125 °C for a melting reaction for 1 - 5 h to obtain a seed mixture.

[0014] S2. Pass in anhydrous ethanol for a crystallization reaction to obtain a crystallization product; the crystallization reaction conditions are: the temperature is 200 - 250 °C, the pressure in the autoclave is 5 - 7 MPa, and the crystallization reaction time is 5 - 10 h.

[0015] S3. Cool, wash, dry, and calcine the crystallization product to obtain the nano H-Beta molecular sieve.

[0016] Further, in S1, the dosages of the silicon source and the aluminum source are calculated based on SiO2 and Al2O3 respectively, and the molar ratio of SiO2, Al2O3, and the template agent is 1:(0.01 - 0.08):(0.15 - 0.25); during the melting reaction, the stirring rate is 400 - 600 r / min.

[0017] Further, in S2, the dosage of the silicon source is calculated based on SiO2, and the molar ratio of SiO2 and anhydrous ethanol is 1:(10.5 - 14.3). During the crystallization reaction, the stirring rate is 30 - 80 r / min.

[0018] Further, the specific operation of S3 is: cool the crystallization product to room temperature, then wash it with deionized water until the pH of the filtrate is 7.0, and finally dry it at 100 - 120 °C for 12 - 24 h and calcine it at 500 - 550 °C for 3 - 5 h to obtain the nano H-Beta molecular sieve.

[0019] Beneficial effects:

[0020] (1) The present invention creatively uses maleic acid ester and ammonium bisulfite as raw materials, uses nano H-Beta molecular sieve as a solid acid catalyst, uses supercritical carbon dioxide as a solvent, and obtains the dialkyl ammonium sulfosuccinate surfactant through an addition reaction.

[0021] In the present invention, the temperature inside the reaction kettle is set to 50 - 70 °C and the pressure is set to 7 - 9 MPa, making carbon dioxide in a supercritical state. The high solubility and high diffusivity of the supercritical carbon dioxide solvent are conducive to the full contact between the raw materials and the catalyst, enabling rapid reaction at low temperature, with short reaction time, high product yield. Moreover, as a solvent, supercritical carbon dioxide has no aqueous solution, avoiding the generation of foam during the reaction, eliminating the need for additional defoaming agents, as the presence of foam would lead to a decline in reaction performance. Additionally, in the inert environment of supercritical carbon dioxide, the double bond in the maleate structure is prevented from being oxidized, eliminating the need for additional nitrogen introduction.

[0022] (2) The present invention innovatively introduces the molten reaction and supercritical ethanol crystallization reaction technologies into the preparation of nano H-Beta molecular sieve.

[0023] The present invention uses the molten reaction to regulate the condensation rate of the silicon source and the aluminum source, making them more compatible, thereby promoting the entry of silicon and aluminum atoms into the framework and generating a mixed material containing a large number of crystal seeds. During the crystallization reaction, the temperature is 200 - 250 °C and the pressure inside the kettle is 5 - 7 MPa, making ethanol in a supercritical state. The present invention utilizes the high solubility, high diffusivity of supercritical ethanol, as well as its performance in regulating the crystal growth rate and morphology, enabling the crystal seed mixed material to fully contact and react in the supercritical crystallization kettle. The crystallization reaction time is short and is conducive to the formation of a large number of molecular sieve precursors with small crystal grain sizes. The final nano H-Beta molecular sieve has small crystal grain sizes, uniform distribution, large specific surface area, high yield, abundant acid active sites, and excellent acid catalytic performance; in this method, water is not used as a solvent, avoiding the generation of wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the characterization result of ammonia adsorption and desorption (NH3-TPD) of the molecular sieves prepared in Example 4, Comparative Example 2, Comparative Example 4, and Comparative Example 5.

[0025] Figure 2 It is the electron microscope (SEM) images of the molecular sieves prepared in Example 4, Comparative Example 1, Comparative Example 2, and Comparative Example 5. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The technical solution of the present invention will be described in detail below with reference to the drawings, but the protection scope of the present invention is not limited to the described embodiments.

[0027] Example 1

[0028] A green surfactant and its preparation method, comprising the following steps:

[0029] Preparation method of nano H-Beta molecular sieve: 20.8 g of silicon source tetraethyl orthosilicate, 0.4 g of aluminum source aluminum isopropoxide and 4.32 g of template N-octanoyl-N-butyldodecylammonium were added to a stainless steel autoclave. The dosages of the silicon source and the aluminum source were calculated based on SiO2 and Al2O3 respectively. The molar ratio of SiO2, Al2O3 and the template was 1:0.01:0.15. The stirring rate was 400 r / min. The temperature was raised to 115 °C for a melting reaction for 5 h to obtain a seed mixture. Then 48.3 g of absolute ethanol was introduced. The molar ratio of SiO2 and absolute ethanol was 1:10.5. The temperature was raised to 200 °C for a crystallization reaction for 10 h. The stirring rate was 30 r / min and the pressure in the autoclave was 5 MPa to obtain a crystallization product. The crystallization product was cooled to room temperature and then washed with deionized water until the pH of the filtrate was 7.0. Finally, it was dried at 120 °C for 12 h and calcined at 500 °C for 5 h to obtain nano H-Beta molecular sieve with a yield of 98.9%.

[0030] Preparation method of dialkyl sulfosuccinate ammonium surfactant: 7.85 g of propyl maleate, 5.45 g of ammonium bisulfite (molar ratio 1:1.1) and 0.07 g of nano H-Beta molecular sieve (dosage was 0.5% of the total mass of the raw materials) were added to a high-pressure autoclave. First, carbon dioxide was introduced for evacuation. Then at 50 °C, 1.23 L of carbon dioxide (molar ratio of carbon dioxide to propyl maleate was 1.1:1) was introduced and the pressure in the autoclave was controlled at 7 MPa for a reaction for 30 min. The stirring rate was 400 r / min. After the reaction, it was cooled to room temperature, the pressure was released, and the nano H-Beta molecular sieve and the excessive ammonium bisulfite were removed by filtration. The filtrate was allowed to stand for stratification, and the lower layer liquid was the dialkyl sulfosuccinate ammonium surfactant with a yield of 99.0%.

[0031] Example 2

[0032] A green surfactant and its preparation method, including the following steps:

[0033] Preparation method of nano H-Beta molecular sieve: 20.8 g of silicon source tetraethyl orthosilicate, 3.2 g of aluminum source aluminum isopropoxide and 7.2 g of template N-octanoyl-N-butyldodecylammonium were added to a stainless steel autoclave. The dosages of the silicon source and aluminum source were calculated based on SiO2 and Al2O3 respectively. The molar ratio of SiO2, Al2O3 and the template was 1:0.08:0.25. The stirring rate was 600 r / min. It was heated to 125 °C for a melting reaction for 1 h to obtain a seed mixture. Then 65.8 g of absolute ethanol was introduced. The molar ratio of SiO2 and absolute ethanol was 1:14.3. It was heated to 250 °C for a crystallization reaction for 5 h. The stirring rate was 80 r / min and the pressure in the autoclave was 7 MPa to obtain a crystallized product. The crystallized product was cooled to room temperature and then washed with deionized water until the pH of the filtrate was 7.0. Finally, it was dried at 100 °C for 24 h and calcined at 550 °C for 3 h to obtain nano H-Beta molecular sieve, and the yield was 99.5%.

[0034] Preparation method of dialkyl sulfosuccinate ammonium surfactant: 9.95 g of hexyl maleate, 7.43 g of ammonium bisulfite (molar ratio 1:1.5) and 0.17 g of nano H-Beta molecular sieve (dosage was 1.0% of the total mass of the raw materials) were added to a high-pressure autoclave. First, carbon dioxide was introduced for evacuation. Then at 70 °C, 1.68 L of carbon dioxide (molar ratio of carbon dioxide to hexyl maleate was 1.5:1) was introduced, and the pressure in the autoclave was controlled at 9 MPa for a reaction for 10 min. The stirring rate was 600 r / min. After the reaction, it was cooled to room temperature, the pressure was released, and the nano H-Beta molecular sieve and excessive ammonium bisulfite were removed by filtration. The filtrate was allowed to stand and separate into layers, and the lower layer liquid was the dialkyl sulfosuccinate ammonium surfactant, and the yield was 99.3%.

[0035] Example 3

[0036] A green surfactant and its preparation method, comprising the following steps:

[0037] Preparation method of nano H-Beta molecular sieve: 20.8 g of silicon source tetraethyl orthosilicate, 2.0 g of aluminum source aluminum isopropoxide and 5.76 g of template N-octanoyl-N-butyldodecylammonium were added to a stainless steel autoclave. The dosages of the silicon source and the aluminum source were calculated based on SiO2 and Al2O3 respectively. The molar ratio of SiO2, Al2O3 and the template was 1:0.05:0.2. The stirring rate was 500 r / min. It was heated to 120 °C for a melting reaction for 3 h to obtain a seed mixture. Then 61.2 g of absolute ethanol was introduced. The molar ratio of SiO2 and absolute ethanol was 1:13.3. It was heated to 230 °C for a crystallization reaction for 8 h. The stirring rate was 50 r / min and the pressure in the autoclave was 6.3 MPa to obtain a crystallization product. The crystallization product was cooled to room temperature and then washed with deionized water until the pH of the filtrate was 7.0. Finally, it was dried at 110 °C for 20 h and calcined at 550 °C for 4 h to obtain nano H-Beta molecular sieve with a yield of 99.1%.

[0038] Preparation method of dialkyl sulfosuccinate ammonium surfactant: 8.55 g of butyl maleate, 6.44 g of ammonium bisulfite (molar ratio 1:1.3) and 0.12 g of nano H-Beta molecular sieve (dosage was 0.8% of the total mass of the raw materials) were added to a high-pressure autoclave. First, carbon dioxide was introduced for evacuation. Then at 70 °C, 1.46 L of carbon dioxide was introduced (the molar ratio of carbon dioxide to butyl maleate was 1.3:1), and the pressure in the autoclave was controlled at 8.5 MPa for a reaction for 15 min. The stirring rate was 500 r / min. After the reaction, it was cooled to room temperature, depressurized, and the nano H-Beta molecular sieve and excessive ammonium bisulfite were removed by filtration. The filtrate was allowed to stand and layer. The lower layer liquid was the dialkyl sulfosuccinate ammonium surfactant with a yield of 99.2%.

[0039] Example 4

[0040] A green surfactant and its preparation method, comprising the following steps:

[0041] Preparation method of nano H-Beta molecular sieve: 20.8 g of silicon source tetraethyl orthosilicate, 2.8 g of aluminum source aluminum isopropoxide and 7.19 g of template N-octanoyl-N-butyldodecylammonium were added to a stainless steel autoclave. The amounts of the silicon source and the aluminum source were calculated based on SiO2 and Al2O3 respectively. The molar ratio of SiO2, Al2O3 and the template was 1:0.07:0.25. The stirring rate was 450 r / min. The temperature was raised to 118 °C for a melting reaction for 4 h to obtain a seed mixture. Then 43.6 g of absolute ethanol was introduced. The molar ratio of SiO2 and absolute ethanol was 1:12.6. The temperature was raised to 220 °C for a crystallization reaction for 10 h. The stirring rate was 60 r / min and the pressure in the autoclave was 6.8 MPa to obtain a crystallization product. The crystallization product was cooled to room temperature and then washed with deionized water until the pH of the filtrate was 7.0. Finally, it was dried at 110 °C for 20 h and calcined at 550 °C for 4 h to obtain nano H-Beta molecular sieve with a yield of 99.3%.

[0042] Preparation method of dialkyl sulfosuccinate ammonium surfactant: 11.35 g of octyl maleate, 7.43 g of ammonium bisulfite (molar ratio 1:1.5) and 0.19 g of nano H-Beta molecular sieve (the amount used was 1.0% of the total mass of the raw materials) were added to a high-pressure autoclave. First, carbon dioxide was introduced for evacuation. Then at 60 °C, 1.68 L of carbon dioxide (the molar ratio of carbon dioxide to octyl maleate was 1.5:1) was introduced, and the pressure in the autoclave was controlled at 8.5 MPa for a reaction for 30 min. The stirring rate was 550 r / min. After the reaction ended, it was cooled to room temperature, the pressure was released, and the nano H-Beta molecular sieve and the excess ammonium bisulfite were removed by filtration. The filtrate was allowed to stand and separate layers. The lower layer liquid was the dialkyl sulfosuccinate ammonium surfactant with a yield of 99.5%.

[0043] Example 5

[0044] A green surfactant and its preparation method, comprising the following steps:

[0045] Preparation method of nano H-Beta molecular sieve: 20.8 g of silicon source tetraethyl orthosilicate, 0.8 g of aluminum source aluminum isopropoxide and 5.18 g of template N-octanoyl-N-butyldodecylammonium acid are added to a stainless steel autoclave. The dosages of the silicon source and aluminum source are calculated based on SiO2 and Al2O3 respectively. The molar ratio of SiO2, Al2O3 and the template is 1:0.02:0.18. The stirring rate is 450 r / min. It is heated to 118 °C for a melting reaction for 4 h to obtain a seed mixture. Then 40.8 g of absolute ethanol is introduced. The molar ratio of SiO2 and absolute ethanol is 1:11.8. It is heated to 220 °C for a crystallization reaction for 6 h. The stirring rate is 60 r / min and the pressure in the autoclave is 5.8 MPa to obtain a crystallized product. The crystallized product is cooled to room temperature and then washed with deionized water until the pH of the filtrate is 7.0. Finally, it is dried at 110 °C for 20 h and calcined at 550 °C for 4 h to obtain nano H-Beta molecular sieve, and the yield is 99.0%.

[0046] Preparation method of dialkyl sulfosuccinate ammonium surfactant: 14.15 g of lauryl maleate, 6.94 g of ammonium bisulfite (molar ratio 1:1.4) and 0.13 g of nano H-Beta molecular sieve (dosage is 0.6% of the total mass of the raw materials) are added to a high-pressure autoclave. First, carbon dioxide is introduced for evacuation, and then at 60 °C, 1.46 L of carbon dioxide is introduced (the molar ratio of carbon dioxide to lauryl maleate is 1.3:1), and the pressure in the autoclave is controlled at 8.0 MPa for a reaction for 20 min. The stirring rate is 450 r / min. After the reaction, it is cooled to room temperature, the pressure is released, and the nano H-Beta molecular sieve and excessive ammonium bisulfite are removed by filtration. The filtrate is allowed to stand and separate layers. The lower layer liquid is the dialkyl sulfosuccinate ammonium surfactant, and the yield is 99.1%.

[0047] Comparative Example 1

[0048] Preparation method of dialkyl sulfosuccinate ammonium surfactant: 11.35 g of octyl maleate, 7.43 g of ammonium bisulfite (molar ratio 1:1.5) and 0.19 g of nano H-Beta molecular sieve prepared in Example 4 (dosage is 1.0% of the total mass of the raw materials) are added to a high-pressure autoclave. At 60 °C, carbon dioxide is continuously introduced into the gas inlet of the autoclave at a flow rate of 0.56 L / min for 30 min, consuming a total of 1.68 L of carbon dioxide (the molar ratio of carbon dioxide to octyl maleate is 1.5:1). Carbon dioxide is continuously discharged from the exhaust port at the same time to keep the pressure in the autoclave at atmospheric pressure. The stirring rate is 550 r / min. After the reaction, it is cooled to room temperature, and the nano H-Beta molecular sieve and unreacted ammonium bisulfite are removed by filtration. The filtrate is allowed to stand and separate layers. The lower layer liquid is the dialkyl sulfosuccinate ammonium surfactant, and the yield is only 8.3%.

[0049] Comparative Example 2

[0050] Preparation method of nano H-Beta molecular sieve: 20.8 g of silicon source tetraethyl orthosilicate, 2.8 g of aluminum source aluminum isopropoxide and 7.19 g of template N-octanoyl-N-butyldodecylammonium were added to a stainless steel autoclave. The dosages of the silicon source and aluminum source were calculated based on SiO2 and Al2O3 respectively. The molar ratio of SiO2, Al2O3 and the template was 1:0.07:0.25. The stirring rate was 450 r / min, and the temperature was raised to 118 °C for a melting reaction for 4 h to obtain a seed mixture. The autoclave was heated to 220 °C for a crystallization reaction for 10 h, the stirring rate was 60 r / min, and the pressure in the autoclave was normal pressure to obtain a crystallized product. The crystallized product was cooled to room temperature, then washed with deionized water until the pH of the filtrate was 7.0, and finally dried at 110 °C for 20 h and calcined at 550 °C for 4 h to obtain H-Beta molecular sieve, and the yield was 99.2%.

[0051] Preparation method of dialkyl sulfosuccinate ammonium surfactant: 11.35 g of octyl maleate, 7.43 g of ammonium bisulfite (molar ratio 1:1.5) and 0.19 g of the H-Beta molecular sieve prepared in the previous step (dosage was 1.0% of the total mass of the raw materials) were added to a high-pressure autoclave. First, carbon dioxide was introduced for evacuation, then at 60 °C, 1.68 L of carbon dioxide (molar ratio of carbon dioxide to octyl maleate was 1.5:1) was introduced, and the pressure in the autoclave was controlled at 8.5 MPa for a reaction for 30 min, the stirring rate was 550 r / min. After the reaction, it was cooled to room temperature, depressurized, and the nano H-Beta molecular sieve and excess ammonium bisulfite were removed by filtration. The filtrate was allowed to stand and separate layers, and the lower layer liquid was the dialkyl sulfosuccinate ammonium surfactant, and the yield was 74.9%.

[0052] Comparative Example 3

[0053] Preparation method of dialkyl sulfosuccinate ammonium surfactant: Add 11.35 g of octyl maleate, 7.43 g of ammonium bisulfite (molar ratio 1:1.5), 0.19 g of the nano H-Beta zeolite prepared in Example 4 (dosage is 1.0% of the total mass of the raw materials), and 13.15 g of ethanol aqueous solution (dosage is 0.7 times the total mass of the raw materials, volume ratio of alcohol to water is 1:5) into a high-pressure reactor. At 60 °C, continuously introduce nitrogen into the gas inlet of the reactor at a flow rate of 0.56 L / min for 30 min, consuming a total of 1.68 L of nitrogen (molar ratio of nitrogen to octyl maleate is 1.5:1). Nitrogen is continuously discharged from the exhaust port at the same time, keeping the pressure in the reactor at atmospheric pressure, and the stirring rate is 550 r / min. After the reaction is completed, cool to room temperature, filter to remove the nano H-Beta zeolite, and let the filtrate stand for stratification. The upper layer liquid is the dialkyl sulfosuccinate ammonium surfactant, and the yield is 32.7%.

[0054] Comparative Example 4

[0055] Add 20.8 g of silicon source tetraethyl orthosilicate, 2.8 g of aluminum source aluminum isopropoxide, 7.19 g of template N-octanoyl-N-butyldodecylammonium, and 43.6 g of absolute ethanol into a stainless steel reactor. The dosages of the silicon source and aluminum source are calculated based on SiO2 and Al2O3 respectively. The molar ratio of SiO2, Al2O3, template, and absolute ethanol is 1:0.07:0.25:12.6. Heat up to 220 °C for crystallization reaction for 10 h, with a stirring rate of 60 r / min and a pressure in the reactor of 6.8 MPa to obtain a crystallization product; cool the crystallization product to room temperature, then wash it with deionized water until the pH of the filtrate is 7.0, and finally dry it at 110 °C for 20 h and calcine it at 550 °C for 4 h to obtain H-Beta zeolite, with a yield of 40.7%;

[0056] Preparation method of dialkyl sulfosuccinate ammonium surfactant: Add 11.35 g of octyl maleate, 7.43 g of ammonium bisulfite (molar ratio 1:1.5), and 0.19 g of the above-prepared H-Beta zeolite (dosage is 1.0% of the total mass of the raw materials) into a high-pressure reactor. First, introduce carbon dioxide for evacuation, then at 60 °C, introduce 1.68 L of carbon dioxide (molar ratio of carbon dioxide to octyl maleate is 1.5:1), and control the pressure in the reactor at 8.5 MPa for reaction for 30 min, with a stirring rate of 550 r / min. After the reaction is completed, cool to room temperature, relieve the pressure, filter to remove the nano H-Beta zeolite and excessive ammonium bisulfite, and let the filtrate stand for stratification. The lower layer liquid is the dialkyl sulfosuccinate ammonium surfactant, and the yield is 89.1%.

[0057] Comparative Example 5

[0058] A green surfactant and its preparation method, comprising the following steps:

[0059] Preparation method of nano H-Beta molecular sieve: Add 20.8 g of silicon source tetraethyl orthosilicate, 2.8 g of aluminum source aluminum isopropoxide and 7.19 g of template N-octanoyl-N-butyldodecylammonium to a grinder. The dosages of the silicon source and aluminum source are calculated based on SiO2 and Al2O3 respectively. The molar ratio of SiO2, Al2O3 and the template is 1:0.07:0.25. Mix and grind (the rotation speed of the grinder is 200 r / min) for 0.8 h to obtain a solid mixture; Place the solid mixture in a supercritical crystallization reactor, introduce carbon dioxide gas, heat to 100 °C for crystallization reaction, the pressure in the reactor is 10 MPa, and the time is 10 h. After cooling to room temperature, obtain the crystallization reaction product; Wash the crystallization reaction product with deionized water until the pH of the filtrate is 7.0, then dry at 100 °C for 24 h, and finally calcine at 500 °C for 5 h to obtain nano H-Beta molecular sieve, and the yield is 97.9%.

[0060] Preparation method of dialkyl ammonium sulfosuccinate surfactant: Add 11.35 g of octyl maleate, 7.43 g of ammonium bisulfite (molar ratio 1:1.5) and 0.19 g of nano H-Beta molecular sieve (the dosage is 1.0% of the total mass of the raw materials) to a high-pressure reactor. First, introduce carbon dioxide for evacuation, then at 60 °C, introduce 1.68 L of carbon dioxide (the molar ratio of carbon dioxide to octyl maleate is 1.5:1), and control the pressure in the reactor at 8.5 MPa for reaction for 30 min, and the stirring rate is 550 r / min. After the reaction, cool to room temperature, relieve the pressure, filter to remove nano H-Beta molecular sieve and excessive ammonium bisulfite, and let the filtrate stand for stratification. The lower layer liquid is the dialkyl ammonium sulfosuccinate surfactant, and the yield is 98.3%.

[0061] The characterization results of the total surface acidity, crystal grain size and specific surface area of the molecular sieves prepared in Example 4 and Comparative Examples 2, 4, and 5 are shown in Table 1. Among them, the total surface acidity is obtained by NH3-TPD characterization, the specific surface area is obtained by BET characterization, and the crystal grain size is obtained by SEM characterization.

[0062] Figure 1 For the ammonia adsorption and desorption (NH3-TPD) characterization results of the molecular sieves prepared in Example 4, Comparative Example 2, Comparative Example 4, and Comparative Example 5, the total surface acidity of the samples can be obtained. Figure 2 SEM images of the molecular sieves prepared in Example 4, Comparative Example 2, Comparative Example 4, and Comparative Example 5.

[0063] Table 1

[0064] sample <![CDATA[Specific surface area (m 2 / g)]]> Grain size (nm) <![CDATA[Amount of acid (μmol NH3 / g cat )]]> Example 4 720 41 378 Comparative Example 4 583 75 216 Comparative Example 2 304 127 131 Comparative Example 5 683 49 327

[0065] In Example 4 of the present invention, during the preparation of the molecular sieve, a large amount of seed mixed material is first generated through a melting reaction, and then, by virtue of the high solubility, high diffusivity of supercritical ethanol, and its performance in regulating the crystal growth rate and morphology, the seed mixed material is fully contacted and reacted in a supercritical crystallization kettle. The crystallization reaction time is short and it is conducive to the formation of a large number of molecular sieve precursors with small grain sizes. The final nano H-Beta molecular sieve has small grain sizes, uniform distribution, a large specific surface area, high yield, and rich acid active sites, so its acid catalytic performance is excellent, and the yield of the obtained dialkyl sulfosuccinate ammonium surfactant is high.

[0066] When preparing the molecular sieve in Comparative Example 2, after a large amount of seed mixed material is generated through a melting reaction, it is directly crystallized at a high temperature. High temperature is likely to cause grain accumulation and sintering (as Figure 2 shown), with large sizes, a small specific surface area, few acidic active sites, and little acid amount, so the catalytic performance is poor, and thus the yield of the obtained dialkyl sulfosuccinate ammonium surfactant is low.

[0067] In Comparative Example 4, during the preparation process of the molecular sieve, since no melting reaction is carried out to form a seed mixture and the crystallization reaction is directly carried out in supercritical ethanol, as ethanol has the effect of slowing down crystal growth and crystals are not easily formed, most of the tetraethyl orthosilicate and aluminum isopropoxide do not undergo crystallization reactions, and tetraethyl orthosilicate and aluminum isopropoxide are easily soluble in ethanol, so they are removed during the washing and filtration processes. Therefore, the yield of the finally formed solid product is relatively low. Moreover, since there is no process of forming seeds through a melting reaction, compared with Example 4, the grain size is larger, the specific surface area is smaller, and the acid amount is less, so the catalytic performance is poorer, and the yield of the obtained dialkyl sulfosuccinate ammonium surfactant is lower.

[0068] In Comparative Example 1, the reaction for preparing the surfactant is not carried out in supercritical carbon dioxide, no solvent is added to the reaction system, and the inorganic salt ammonium bisulfite is immiscible with the organic solvent dioctyl maleate, so the reaction performance is poor, and thus the product yield is extremely low.

[0069] In Comparative Example 3, ethanol aqueous solution is used as the reaction solvent, so that the inorganic salt ammonium bisulfite and the organic solvent octyl butenedioate are more likely to react, so the surfactant yield obtained is higher than that in Comparative Example 1, but lower than the surfactant yield obtained by taking supercritical carbon dioxide as the reaction solvent in Example 4, because the high solubility and high diffusivity of the supercritical carbon dioxide solvent are more conducive to the full contact between the raw material and the catalyst, and the rapid reaction at low temperature is short, the product yield is high, and supercritical carbon dioxide is used as a solvent, and there is no aqueous solution, which avoids the generation of foam in the reaction process, and does not need to add a defoamer, and the presence of foam will cause a decrease in reaction performance; and in the inert environment of supercritical carbon dioxide, the double bonds in the butenedioate structure are avoided from being oxidized, and there is no need to pass nitrogen gas additionally.

[0070] In the comparative example 5, the preparation method of nano H-Beta molecular sieve is first to obtain a solid-phase reaction mixture by a grinding method, and then to carry out a crystallization reaction under supercritical carbon dioxide conditions. Compared with the grinding method, the raw materials in the molten state contact and react more fully, which is conducive to the production of a large number of crystal seeds. Under the condition of the same amount of raw materials, the more crystal seeds there are, the smaller the final grain size will be. In addition, ethanol has the effect of slowing down crystal growth, which is more conducive to the formation of molecular sieve crystals with small grain size. Therefore, the molecular sieve yield obtained in comparative example 5 is lower than that in example 4, and the grain size (49nm) is larger than the molecular sieve grain size (41nm) obtained in example 4. The specific surface area and acid content are both lower than those of the molecular sieve obtained in example 4. Therefore, its catalytic performance is poor and the obtained surfactant yield is low.

[0071] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to the form and details without departing from the spirit and scope of the present invention.

Claims

1. A preparation method of a green surfactant, characterized in that, It includes the following steps: Step 1: Add maleic acid ester, ammonium bisulfite, and the catalyst nano H-Beta zeolite into a high-pressure reactor, and introduce carbon dioxide for evacuation. Step 2: Set the temperature of the reactor to 50 - 70 °C, then introduce carbon dioxide, and control the reactor pressure to react at 7 - 9 MPa for 10 - 30 min. After that, filter to obtain the filtrate, which is the dialkyl ammonium sulfosuccinate surfactant. The reaction equation is as follows: Among them, R is a straight-chain alkyl group with C3 - C12.

2. The preparation method according to claim 1, wherein In Step 1, the molar ratio of maleic acid ester to ammonium bisulfite is 1:(1.1 - 1.5); in Step 2, the molar ratio of introduced carbon dioxide to maleic acid ester is (1.1 - 1.5):

1.

3. The preparation method according to claim 1, wherein In Step 1, the dosage of the nano H-Beta zeolite is 0.5 - 1.0% of the total mass of the raw materials.

4. The preparation method according to claim 1, characterized in that, In Step 2, the stirring rate is 400 - 600 r / min.

5. The preparation method according to claim 1, characterized in that The preparation method of the nano H-Beta zeolite is as follows: S1: Add tetraethyl orthosilicate as the silicon source, aluminum isopropoxide as the aluminum source, and N-octanoyl-N-butyldodecylammonium as the template agent into a stainless-steel reactor, heat up to 115 - 125 °C for melting reaction for 1 - 5 h to obtain a seed mixture. S2: Introduce anhydrous ethanol for crystallization reaction. The temperature of the crystallization reaction is 200 - 250 °C, and the pressure is 5 - 7 MPa. S3: Cool, wash, dry, and calcine the crystallization product to obtain nano H-Beta zeolite.

6. The preparation method according to claim 5, characterized in that, In S1, the dosages of the silicon source and aluminum source are calculated based on SiO2 and Al2O3 respectively. The molar ratio of SiO2, Al2O3, and the template agent is 1:(0.01 - 0.08):(0.15 - 0.25). In S2, the molar ratio of the introduced amount of anhydrous ethanol to the dosage of the silicon source is (10.5 - 14.3):1, and the dosage of the silicon source is calculated based on SiO2.

7. The preparation method according to claim 5, characterized in that, In S1, during the melting reaction, the stirring rate is 400 - 600 r / min; in S2, during the crystallization reaction, the stirring rate is 30 - 80 r / min.

8. The preparation method according to claim 5, characterized in that, The specific operation of S3 is: Cool the crystallization product to room temperature, then wash it with deionized water until the pH of the filtrate is 7.

0. Finally, dry it at 100 - 120 °C for 12 - 24 h and calcine it at 500 - 550 °C for 3 - 5 h to obtain nano H-Beta zeolite.

9. The green surfactant prepared by the preparation method described in any one of claims 1 - 8.

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