A process for the preparation of a blowing agent

Abstract

The present application relates to the technical field of ore flotation, and discloses a preparation process of a foaming agent. The foaming agent is obtained by mixing fluorine-containing modified pyridine modified carboxy betaine, sulfonic acid group modified polyoxyethylene ether and methyl isobutyl carbinol. The fluorine atom can enhance the stability of the foaming agent and improve the flotation effect. The sulfur atom forms a stable chelate with metal ions, realizing the separation and purification of minerals. The pyridyl group can be electrostatically attracted to the surface of the mineral to form a hydrophobic film, improving the adhesion between the bubbles and the mineral and enhancing the flotation effect. The polar group in the carboxy betaine is adsorbed on the surface of the mineral, and the non-polar group faces outward, making the surface of the mineral hydrophobic and playing a role in flotation. The sulfonic acid group can be adsorbed on the surface of the mineral, making the originally hydrophilic mineral surface hydrophobic and improving the floatability of the mineral. The polyoxyethylene ether has good dispersing performance, making the foaming agent more uniformly distributed in the ore pulp, so that the mineral can be better captured by the bubbles and floated.

Description

Technical Field

[0001] This invention relates to the field of ore flotation technology, specifically to a process for preparing a frother. Background Technology

[0002] Foam flotation is a separation method that utilizes the differences in the physicochemical properties of mineral surfaces at the gas-liquid-solid three-phase interface to separate valuable minerals from gangue minerals, or one (or more) valuable minerals from other valuable minerals, using flotation equipment. Most minerals have high surface wettability and poor floatability, making separation difficult solely based on natural floatability. Therefore, flotation reagents are needed to alter the physicochemical properties of the mineral surface, increasing the hydrophobicity of mineral particles and the strength of mineral adhesion to air bubbles, thereby changing the mineral's floatability and achieving separation between minerals. Frothing agents are one of the main reagents in mineral flotation. Frothing agents are reagents that, during the flotation process, effectively disperse air into fine bubbles in the pulp, prevent bubble coalescence and collapse during bubble ascent, and improve foam stability. Currently used frothers have the problem of insufficient mineral selectivity; while they may float the target mineral, they may also cause some non-target minerals to float simultaneously, thus affecting the concentrate grade. Frothing agents typically need to be used in combination with other flotation reagents such as collectors and modifiers. However, the synergistic effect between different reagents can be affected by various factors, and poor synergy can negatively impact flotation performance. The literature "Synthesis of Commonly Used Frothing Agent No. 2 Oil" describes the preparation of a commonly used frothing agent No. 2 oil using natural turpentine oil as raw material and a one-step sulfuric acid-catalyzed hydration reaction. However, its flotation performance still needs improvement. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] To address the shortcomings of existing technologies, this invention provides a process for preparing a frother. The frother prepared by this invention combines frother-generating and collecting effects, exhibiting good flotation performance for minerals.

[0005] (II) Technical Solution

[0006] To achieve the above objectives, the present invention provides the following technical solution: a preparation process for a foaming agent, wherein the preparation process for the foaming agent includes the following steps:

[0007] (1) Add 11-17g of 5,5,5-trifluoropentanol, 10-15g of 2,6-dichloro-4-mercaptopyridine, and 0.02-0.03g of sodium hydride catalyst to tetrahydrofuran solvent, stir and mix, heat to the reaction temperature and react for 3-4h. After the reaction is completed, filter, wash and dry to obtain fluorine-modified mercaptopyridine.

[0008] (2) Add 4-8g of dimethylaminoethyl methacrylate and 12-18g of 5-bromopentanoic acid to anhydrous ethanol solvent, stir to dissolve, then add 0.07-0.09g of catalyst, purge with nitrogen for 15-35min to remove oxygen, and heat to 32-45℃ under nitrogen protection for 17-20h. After the reaction is completed, filter, dry at 30-35℃ for 2-4h, add deionized water to dissolve, extract with diethyl ether, and freeze dry the aqueous phase to obtain carboxybetaine intermediate;

[0009] (3) Add 9-13g of carboxybetaine intermediate and 6-10g of fluorine-modified mercaptopyridine to N,N-dimethylformamide solvent, stir and mix, then add 0.03-0.05g of benzoin dimethyl ether photoinitiator, irradiate with 365nm ultraviolet light at 35-45℃, after the reaction is completed, centrifuge, wash and dry to obtain fluorine-modified pyridine-modified carboxybetaine;

[0010] (4) Add 10-14g of sodium bisulfite to deionized water, and heat while stirring until the sodium bisulfite dissolves. Raise the temperature to 68-74℃, and add 6-9g of 1,2-epoxydodecane dropwise. After the addition is complete, raise the temperature to 82-90℃ and keep the reaction at that temperature for 3-6 hours. After the reaction is complete, cool the reaction solution in an ice-water bath, filter the crystals that precipitate after cooling, and recrystallize to obtain the sulfonic acid group modified initiator.

[0011] (5) Add 7-11g of sulfonic acid modified initiator and 0.05-0.08g of catalyst to the reactor, heat to 110-120℃, purge with nitrogen for 25-40min to replace the air, heat to 145-160℃, and add 12-15g of ethylene oxide dropwise while stirring. After the addition is complete, keep the reaction at the temperature for 4-7h. After the reaction is complete, sulfonic acid modified polyoxyethylene ether is obtained.

[0012] (6) Add 24-30 parts by weight of fluorine-modified pyridine-modified carboxybetaine, 14-18 parts by weight of sulfonic acid-modified polyoxyethylene ether, and 2-6 parts by weight of methyl isobutyl methanol to the reactor and stir and mix at 400-800 rpm to obtain a foaming agent.

[0013] Preferably, the reaction temperature in step (1) is 42-50℃.

[0014] Preferably, the catalyst in step (2) is potassium iodide.

[0015] Preferably, the ultraviolet irradiation time in step (3) is 3.5-4 hours.

[0016] Preferably, the dropping time of 1,2-epoxydodecane in step (4) is 2-2.5 h.

[0017] Preferably, the catalyst in step (5) is sodium hydroxide.

[0018] Preferably, the ethylene oxide is added in step (5) over a period of 50-60 minutes.

[0019] Preferably, the stirring time in step (6) is 20-50 min.

[0020] (III) Beneficial Technical Effects

[0021] The present invention obtains a foaming agent by stirring and mixing fluorine-modified pyridine-modified carboxybetaine, sulfonic acid-modified polyoxyethylene ether, and methyl isobutyl methanol.

[0022] The hydroxyl group in 5,5,5-trifluoropentanol and the chlorine in 2,6-dichloro-4-mercaptopyridine undergo a substitution reaction to give fluorinated modified mercaptopyridine. The tertiary amine in dimethylaminoethyl methacrylate and 5-bromopentanoic acid undergo a quaternization reaction to give a carboxybetaine intermediate. The alkenyl group in the carboxybetaine intermediate and the thiol group in the fluorinated modified mercaptopyridine undergo a click reaction to give fluorinated modified pyridine-modified carboxybetaine. Sodium bisulfite and 1,2-epoxydodecane undergo a ring-opening addition reaction to introduce a hydroxyl group, giving a sulfonic acid-modified initiator. The sulfonic acid-modified initiator and ethylene oxide undergo a polymerization reaction to give a sulfonic acid-modified polyoxyethylene ether.

[0023] In fluorine-modified pyridine-modified carboxylated betaine, the fluorine atom possesses high electronegativity and chemical stability, enhancing the chemical bond strength and overall stability of the frother molecule. During flotation, various chemical substances in the pulp and complex environmental conditions may affect the frother. Fluorine-containing frothers, due to their better chemical stability, can better resist these factors, maintaining their frother performance and thus improving flotation efficiency. The sulfur atom, acting as a coordinating atom, forms a stable chelate with metal ions, capturing them from the mineral surface and introducing them into the solution phase, achieving mineral separation and purification. The pyridine group carries lone pairs of electrons, enabling electrostatic attraction with metal cations on the mineral surface to form a hydrophobic film, preventing water molecules from contacting the mineral surface and further increasing the mineral's hydrophobicity. This hydrophobic film helps improve the adhesion between bubbles and minerals, making it easier for minerals to float to the pulp surface with the bubbles. Enhancing flotation effect: Carboxybenzene is an amphoteric surfactant with both carboxyl and cationic groups. When dissolved in water, its polar groups adsorb onto the mineral surface, while the non-polar groups face outwards, making the mineral surface hydrophobic. Simultaneously, the van der Waals forces between its molecules provide strength to the hydrophobic film on the mineral surface, thus contributing to flotation. The sulfonic acid groups in sulfonic acid-modified polyoxyethylene ether adsorb onto the mineral surface, transforming the originally hydrophilic mineral surface into a hydrophobic one. This facilitates bubble adhesion to the mineral surface, improving floatability and enhancing flotation performance. The polyoxyethylene ether molecule contains hydrophilic ether groups and hydrophobic long-chain alkyl groups, allowing it to adsorb at the gas-liquid interface, reducing the surface tension of the liquid and making bubble formation easier. Furthermore, polyoxyethylene ether has good dispersibility, enabling more uniform distribution of the frother in the slurry, increasing the contact opportunity between the frother and the mineral surface, and allowing the mineral to be better captured and floated by bubbles. The synergistic effect of multiple functional groups further improves the flotation performance of the frother. Detailed Implementation

[0024] Example 1

[0025] (1) Add 11g of 5,5,5-trifluoropentanol, 10g of 2,6-dichloro-4-mercaptopyridine and 0.02g of sodium hydride catalyst to tetrahydrofuran solvent, stir and mix, heat to 42℃ and react for 3h. After the reaction is completed, filter, wash and dry to obtain fluorine-modified mercaptopyridine.

[0026] (2) Add 4g of dimethylaminoethyl methacrylate and 12g of 5-bromopentanoic acid to anhydrous ethanol solvent, stir to dissolve, then add 0.07g of potassium iodide catalyst, purge with nitrogen for 15min to remove oxygen, heat to 32℃ under nitrogen protection and react for 17h. After the reaction is completed, filter, dry at 30℃ for 2h, add deionized water to dissolve, extract with diethyl ether and freeze dry the aqueous phase to obtain carboxybetaine intermediate;

[0027] (3) Add 9g of carboxybetaine intermediate and 6g of fluorine-modified mercaptopyridine to N,N-dimethylformamide solvent, stir and mix, then add 0.03g of benzoin dimethyl ether photoinitiator, irradiate with 365nm ultraviolet light at 35℃ for 3.5h, after the reaction is completed, centrifuge, wash and dry to obtain fluorine-modified pyridine-modified carboxybetaine;

[0028] (4) Add 10g of sodium bisulfite to deionized water and heat while stirring until the sodium bisulfite dissolves. Raise the temperature to 68°C and add 6g of 1,2-epoxydodecane dropwise. The addition is completed in 2 hours. Raise the temperature to 82°C and keep the reaction for 3 hours. After the reaction is completed, cool the reaction solution in an ice-water bath. Filter the crystals that precipitate after cooling and recrystallize to obtain the sulfonic acid group modified initiator.

[0029] (5) Add 7g of sulfonic acid modified initiator and 0.05g of sodium hydroxide catalyst to the reactor, heat to 110°C, purge with nitrogen for 25min to replace the air, heat to 145°C, and add 12g of ethylene oxide dropwise while stirring. The addition is completed in 50min. Keep the reaction at the temperature for 4h. After the reaction is completed, sulfonic acid modified polyoxyethylene ether is obtained.

[0030] (6) Add 24 parts by weight of fluorine-modified pyridine-modified carboxybetaine, 14 parts by weight of sulfonic acid-modified polyoxyethylene ether, and 2 parts by weight of methyl isobutyl methanol to the reactor, and stir and mix at 400 rpm for 20 min to obtain a foaming agent.

[0031] Example 2

[0032] (1) Add 17g of 5,5,5-trifluoropentanol, 15g of 2,6-dichloro-4-mercaptopyridine and 0.03g of sodium hydride catalyst to tetrahydrofuran solvent, stir and mix, heat to 50℃ and react for 4h. After the reaction is completed, filter, wash and dry to obtain fluorine-modified mercaptopyridine.

[0033] (2) Add 8g of dimethylaminoethyl methacrylate and 18g of 5-bromopentanoic acid to anhydrous ethanol solvent, stir to dissolve, then add 0.09g of potassium iodide catalyst, purge with nitrogen for 35min to remove oxygen, heat to 45℃ under nitrogen protection and react for 20h. After the reaction is completed, filter, dry at 35℃ for 4h, add deionized water to dissolve, extract with diethyl ether and freeze dry the aqueous phase to obtain carboxybetaine intermediate;

[0034] (3) Add 13g of carboxybetaine intermediate and 10g of fluorine-modified mercaptopyridine to N,N-dimethylformamide solvent, stir and mix, then add 0.05g of benzoin dimethyl ether photoinitiator, irradiate with 365nm ultraviolet light at 45℃ for 4h, after the reaction is completed, centrifuge, wash and dry to obtain fluorine-modified pyridine-modified carboxybetaine;

[0035] (4) Add 14g of sodium bisulfite to deionized water and heat while stirring until the sodium bisulfite dissolves. Raise the temperature to 74°C and add 9g of 1,2-epoxydodecane dropwise. The addition is completed in 2.5h. Raise the temperature to 90°C and keep the reaction for 6h. After the reaction is completed, cool the reaction solution in an ice-water bath. Filter the crystals that precipitate after cooling and recrystallize to obtain the sulfonic acid group modified initiator.

[0036] (5) Add 11g of sulfonic acid modified initiator and 0.08g of sodium hydroxide catalyst to the reactor, heat to 120°C, purge with nitrogen for 40min to replace the air, heat to 160°C, and add 15g of ethylene oxide dropwise while stirring. The addition is completed in 60min. Keep the reaction at the temperature for 7h. After the reaction is completed, sulfonic acid modified polyoxyethylene ether is obtained.

[0037] (6) Add 30 parts by weight of fluorine-modified pyridine-modified carboxybetaine, 18 parts by weight of sulfonic acid-modified polyoxyethylene ether, and 6 parts by weight of methyl isobutyl methanol to the reactor, and stir and mix at 800 rpm for 50 min to obtain a foaming agent.

[0038] Example 3

[0039] (1) Add 14g of 5,5,5-trifluoropentanol, 12.5g of 2,6-dichloro-4-mercaptopyridine, and 0.025g of sodium hydride catalyst to tetrahydrofuran solvent, stir and mix, heat to 46℃ and react for 3.5h. After the reaction is completed, filter, wash and dry to obtain fluorine-modified mercaptopyridine.

[0040] (2) Add 6g of dimethylaminoethyl methacrylate and 15g of 5-bromopentanoic acid to anhydrous ethanol solvent, stir to dissolve, then add 0.08g of potassium iodide catalyst, purge with nitrogen for 25min to remove oxygen, heat to 38.5℃ under nitrogen protection and react for 18.5h. After the reaction is completed, filter, dry at 32℃ for 3h, add deionized water to dissolve, extract with diethyl ether and freeze dry the aqueous phase to obtain carboxybetaine intermediate;

[0041] (3) Add 11g of carboxybetaine intermediate and 8g of fluorine-modified mercaptopyridine to N,N-dimethylformamide solvent, stir and mix, then add 0.04g of benzoin dimethyl ether photoinitiator, irradiate with 365nm ultraviolet light at 40℃ for 3.8h, after the reaction is completed, centrifuge, wash and dry to obtain fluorine-modified pyridine-modified carboxybetaine;

[0042] (4) Add 12g of sodium bisulfite to deionized water and heat while stirring until the sodium bisulfite dissolves. Raise the temperature to 71°C and add 7.5g of 1,2-epoxydodecane dropwise. The addition is completed in 2.2h. Raise the temperature to 86°C and keep the reaction at that temperature for 4.5h. After the reaction is completed, cool the reaction solution in an ice-water bath. Filter the crystals that precipitate after cooling and recrystallize to obtain the sulfonic acid group modified initiator.

[0043] (5) Add 9g of sulfonic acid modified initiator and 0.065g of sodium hydroxide catalyst to the reactor, heat to 115℃, purge with nitrogen for 32min to replace the air, heat to 152℃, and add 13.5g of ethylene oxide dropwise while stirring. The addition is completed in 55min. Keep the reaction at the temperature for 5.5h. After the reaction is completed, sulfonic acid modified polyoxyethylene ether is obtained.

[0044] (6) Add 27 parts by weight of fluorine-modified pyridine-modified carboxybetaine, 16 parts by weight of sulfonic acid-modified polyoxyethylene ether, and 4 parts by weight of methyl isobutyl methanol to the reactor, and stir and mix at 600 rpm for 35 min to obtain a foaming agent.

[0045] Example 4

[0046] (1) Add 11g of 5,5,5-trifluoropentanol, 10g of 2,6-dichloro-4-mercaptopyridine and 0.02g of sodium hydride catalyst to tetrahydrofuran solvent, stir and mix, heat to 42℃ and react for 3h. After the reaction is completed, filter, wash and dry to obtain fluorine-modified mercaptopyridine.

[0047] (2) Add 4g of dimethylaminoethyl methacrylate and 12g of 5-bromopentanoic acid to anhydrous ethanol solvent, stir to dissolve, then add 0.07g of potassium iodide catalyst, purge with nitrogen for 15min to remove oxygen, heat to 32℃ under nitrogen protection and react for 17h. After the reaction is completed, filter, dry at 30℃ for 2h, add deionized water to dissolve, extract with diethyl ether and freeze dry the aqueous phase to obtain carboxybetaine intermediate;

[0048] (3) Add 13g of carboxybetaine intermediate and 10g of fluorine-modified mercaptopyridine to N,N-dimethylformamide solvent, stir and mix, then add 0.05g of benzoin dimethyl ether photoinitiator, irradiate with 365nm ultraviolet light at 45℃ for 4h, after the reaction is completed, centrifuge, wash and dry to obtain fluorine-modified pyridine-modified carboxybetaine;

[0049] (4) Add 14g of sodium bisulfite to deionized water and heat while stirring until the sodium bisulfite dissolves. Raise the temperature to 74°C and add 9g of 1,2-epoxydodecane dropwise. The addition is completed in 2.5h. Raise the temperature to 90°C and keep the reaction for 6h. After the reaction is completed, cool the reaction solution in an ice-water bath. Filter the crystals that precipitate after cooling and recrystallize to obtain the sulfonic acid group modified initiator.

[0050] (5) Add 9g of sulfonic acid modified initiator and 0.065g of sodium hydroxide catalyst to the reactor, heat to 115℃, purge with nitrogen for 32min to replace the air, heat to 152℃, and add 13.5g of ethylene oxide dropwise while stirring. The addition is completed in 55min. Keep the reaction at the temperature for 5.5h. After the reaction is completed, sulfonic acid modified polyoxyethylene ether is obtained.

[0051] (6) Add 27 parts by weight of fluorine-modified pyridine-modified carboxybetaine, 16 parts by weight of sulfonic acid-modified polyoxyethylene ether, and 4 parts by weight of methyl isobutyl methanol to the reactor, and stir and mix at 600 rpm for 35 min to obtain a foaming agent.

[0052] Example 5

[0053] (1) Add 14g of 5,5,5-trifluoropentanol, 12.5g of 2,6-dichloro-4-mercaptopyridine, and 0.025g of sodium hydride catalyst to tetrahydrofuran solvent, stir and mix, heat to 46℃ and react for 3.5h. After the reaction is completed, filter, wash and dry to obtain fluorine-modified mercaptopyridine.

[0054] (2) Add 6g of dimethylaminoethyl methacrylate and 15g of 5-bromopentanoic acid to anhydrous ethanol solvent, stir to dissolve, then add 0.08g of potassium iodide catalyst, purge with nitrogen for 25min to remove oxygen, heat to 38.5℃ under nitrogen protection and react for 18.5h. After the reaction is completed, filter, dry at 32℃ for 3h, add deionized water to dissolve, extract with diethyl ether and freeze dry the aqueous phase to obtain carboxybetaine intermediate;

[0055] (3) Add 13g of carboxybetaine intermediate and 10g of fluorine-modified mercaptopyridine to N,N-dimethylformamide solvent, stir and mix, then add 0.05g of benzoin dimethyl ether photoinitiator, irradiate with 365nm ultraviolet light at 45℃ for 4h, after the reaction is completed, centrifuge, wash and dry to obtain fluorine-modified pyridine-modified carboxybetaine;

[0056] (4) Add 14g of sodium bisulfite to deionized water and heat while stirring until the sodium bisulfite dissolves. Raise the temperature to 74°C and add 9g of 1,2-epoxydodecane dropwise. The addition is completed in 2.5h. Raise the temperature to 90°C and keep the reaction for 6h. After the reaction is completed, cool the reaction solution in an ice-water bath. Filter the crystals that precipitate after cooling and recrystallize to obtain the sulfonic acid group modified initiator.

[0057] (5) Add 7g of sulfonic acid modified initiator and 0.05g of sodium hydroxide catalyst to the reactor, heat to 110°C, purge with nitrogen for 25min to replace the air, heat to 145°C, and add 12g of ethylene oxide dropwise while stirring. The addition is completed in 50min. Keep the reaction at the temperature for 4h. After the reaction is completed, sulfonic acid modified polyoxyethylene ether is obtained.

[0058] (6) Add 24 parts by weight of fluorine-modified pyridine-modified carboxybetaine, 14 parts by weight of sulfonic acid-modified polyoxyethylene ether, and 2 parts by weight of methyl isobutyl methanol to the reactor, and stir and mix at 400 rpm for 20 min to obtain a foaming agent.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that fluorine-modified pyridine carboxybetaine was not added in step (6).

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 1 is that sulfonic acid-modified polyoxyethylene ether was not added in step (6).

[0063] Flotation test of copper sulfide ore: The ore sample was crushed to 2 mm, and 1 kg of the sample was ground in an SMQ240×90 conical ball mill for 15 min at a pulp concentration of 62.5% until 65% of the sample was 0.074 mm. Then, flotation was performed in an XFD-3L laboratory single-cell flotation machine at a speed of 2070 r / min. The frother dosage was 30 g / t. The test results are shown in Table 1.

[0064] Table 1: Results of flotation tests on copper sulfide ores:

[0065] project Copper grade (%) Copper recovery rate (%) Example 1 34.7 95.3 Example 2 36.6 96.0 Example 3 32.5 96.4 Example 4 35.4 94.8 Example 5 36.9 95.7 Comparative Example 1 19.4 82.6 Comparative Example 2 22.8 86.1

[0066] Flotation test of lead-zinc sulfide ore: The ore sample was crushed to 2 mm, and 300 g of the sample was ground in an SMQ240×90 conical ball mill for 1.5 min at a pulp concentration of 60% until 70% of the sample was 0.074 mm. Then, flotation was performed in an XFD-1L laboratory single-cell flotation machine at a speed of 2070 r / min. The frother dosage was 40 g / t. The test results are shown in Table 2.

[0067] Table 2: Results of flotation tests on lead-zinc sulfide ores:

[0068]

[0069] As shown in Tables 1 and 2, the frothers in Examples 1-5 of the present invention have a better flotation effect on minerals compared with the frothers in Comparative Examples 1-2.

[0070] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A process for preparing a foaming agent, characterized in that, The preparation process of the foaming agent includes the following steps: (1) Add 11-17g of 5,5,5-trifluoropentanol, 10-15g of 2,6-dichloro-4-mercaptopyridine, and 0.02-0.03g of sodium hydride catalyst to tetrahydrofuran solvent, stir and mix, heat to the reaction temperature and react for 3-4h. After the reaction is completed, filter, wash and dry to obtain fluorine-modified mercaptopyridine. (2) Add 4-8g of dimethylaminoethyl methacrylate and 12-18g of 5-bromopentanoic acid to anhydrous ethanol solvent, stir to dissolve, then add 0.07-0.09g of catalyst, purge with nitrogen for 15-35min to remove oxygen, and heat to 32-45℃ under nitrogen protection for 17-20h. After the reaction is completed, filter, dry at 30-35℃ for 2-4h, add deionized water to dissolve, extract with diethyl ether, and freeze dry the aqueous phase to obtain carboxybetaine intermediate; (3) Add 9-13g of carboxybetaine intermediate and 6-10g of fluorine-modified mercaptopyridine to N,N-dimethylformamide solvent, stir and mix, then add 0.03-0.05g of benzoin dimethyl ether photoinitiator, irradiate with 365nm ultraviolet light at 35-45℃, after the reaction is completed, centrifuge, wash and dry to obtain fluorine-modified pyridine-modified carboxybetaine; (4) Add 10-14g of sodium bisulfite to deionized water, and heat while stirring until the sodium bisulfite dissolves. Raise the temperature to 68-74℃, and add 6-9g of 1,2-epoxydodecane dropwise. After the addition is complete, raise the temperature to 82-90℃ and keep the reaction at that temperature for 3-6 hours. After the reaction is complete, cool the reaction solution in an ice-water bath, filter the crystals that precipitate after cooling, and recrystallize to obtain the sulfonic acid group modified initiator. (5) Add 7-11g of sulfonic acid modified initiator and 0.05-0.08g of catalyst to the reactor, heat to 110-120℃, purge with nitrogen for 25-40min to replace the air, heat to 145-160℃, and add 12-15g of ethylene oxide dropwise while stirring. After the addition is complete, keep the reaction at the temperature for 4-7h. After the reaction is complete, sulfonic acid modified polyoxyethylene ether is obtained. (6) Add 24-30 parts by weight of fluorine-modified pyridine-modified carboxybetaine, 14-18 parts by weight of sulfonic acid-modified polyoxyethylene ether, and 2-6 parts by weight of methyl isobutyl methanol to the reactor and stir and mix at 400-800 rpm to obtain a foaming agent.

2. The preparation process of the foaming agent according to claim 1, characterized in that, The reaction temperature in step (1) is 42-50℃.

3. The preparation process of the foaming agent according to claim 1, characterized in that, The catalyst in step (2) is potassium iodide.

4. The preparation process of the foaming agent according to claim 1, characterized in that, The ultraviolet light irradiation time in step (3) is 3.5-4 hours.

5. The preparation process of the foaming agent according to claim 1, characterized in that, In step (4), the dropping time of 1,2-epoxydodecane is 2-2.5 h.

6. The preparation process of the foaming agent according to claim 1, characterized in that, The catalyst in step (5) is sodium hydroxide.

7. The preparation process of the foaming agent according to claim 1, characterized in that, In step (5), the ethylene oxide is added over a period of 50-60 minutes.

8. The preparation process of the foaming agent according to claim 1, characterized in that, The stirring time in step (6) is 20-50 minutes.

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