Preparation process of foaming agent

Abstract

The invention 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 pyridine modified carboxyl betaine, sulfonic group modified polyoxyethylene ether and methyl isobutyl carbinol. Fluorine atoms can enhance the stability of the foaming agent and improve the flotation effect; sulfur atoms and metal ions form a stable chelate, and mineral separation and purification are achieved; pyridyl can generate electrostatic attraction with the surface of the mineral to form a hydrophobic membrane, so that the adhesive force of bubbles and the mineral is improved, and the flotation effect is enhanced; polar groups in the carboxyl betaine are adsorbed on the surfaces of the minerals, and non-polar groups face outwards, so that the surfaces of the minerals are hydrophobic, and a flotation effect is achieved; sulfonic groups can be adsorbed on the surfaces of minerals, so that the original hydrophilic surfaces of the minerals are changed into hydrophobic surfaces, and the floatability of the minerals is improved; the polyoxyethylene ether has good dispersing performance, so that the foaming agent is more uniformly distributed in ore pulp, and minerals can be better captured by bubbles and float upwards.

Description

Technical Field

[0001] The invention relates to the technical field of ore flotation, in particular to a preparation process of a foaming agent. Background Art

[0002] Froth flotation is a separation method that utilizes the differences in the physical and chemical properties of mineral surfaces at the gas-liquid-solid interface to separate useful minerals from gangue minerals, or one or more useful minerals from other useful minerals, using flotation equipment. Most minerals have high surface wettability and poor floatability, making them difficult to separate based solely on their natural floatability. Therefore, flotation agents are used to modify the physical and chemical properties of the mineral surface, increasing the hydrophobicity of the mineral particles and the firmness of the minerals' adhesion to air bubbles, thereby altering their floatability and achieving separation. Frothing agents are one of the primary agents in mineral flotation. During the flotation process, frothers effectively disperse air into fine bubbles within the slurry, preventing them from coalescing and collapsing during their rise, and improving froth stability. Currently, commonly used frothers suffer from suboptimal mineral selectivity. While the target mineral may float, they may also cause non-target minerals to float, affecting the concentrate grade. Typically, frothers are used in conjunction with other flotation agents, such as collectors and regulators. However, the synergistic effect between these agents can be affected by various factors. Poor synergy can negatively impact flotation performance. The paper "Synthesis of No. 2 Oil, a Common Frothing Agent for Flotation" uses natural turpentine as a raw material and utilizes sulfuric acid-catalyzed hydration to prepare a commonly used flotation frother, No. 2 Oil, in a single step. However, its flotation performance remains to be improved. Summary of the Invention

[0003] (1) Technical problems solved

[0004] In view of the shortcomings of the prior art, the present invention provides a process for preparing a foaming agent. The foaming agent prepared by the present invention has both foaming and collecting effects and has a good flotation effect on minerals.

[0005] (2) Technical solution

[0006] To achieve the above object, the present invention provides the following technical solution: a process for preparing a foaming agent, the process for preparing the foaming agent comprising the following steps:

[0007] (1) Adding 11-17 g of 5,5,5-trifluoropentanol, 10-15 g of 2,6-dichloro-4-mercaptopyridine, and 0.02-0.03 g of sodium hydride catalyst to tetrahydrofuran solvent, stirring and mixing, heating to the reaction temperature and reacting for 3-4 hours. After the reaction is completed, filtering, washing, and drying to obtain fluorine-modified mercaptopyridine;

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

[0009] (3) adding 9-13 g of the carboxybetaine intermediate and 6-10 g of fluorine-modified mercaptopyridine to an N,N-dimethylformamide solvent, stirring and mixing, and then adding 0.03-0.05 g of benzoin dimethyl ether photoinitiator thereto, irradiating with 365 nm ultraviolet light at 35-45 ° C. After the reaction is completed, centrifugation, washing and drying are performed to obtain fluorine-modified pyridine-modified carboxybetaine;

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

[0011] (5) Add 7-11 g of sulfonic acid modified initiator and 0.05-0.08 g of catalyst to a reactor, heat to 110-120 ° C, introduce nitrogen for 25-40 min to replace the air, heat to 145-160 ° C, add 12-15 g of ethylene oxide dropwise while stirring, and after the addition is complete, keep warm for 4-7 hours. After the reaction is completed, a 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 carbinol into a 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°C.

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

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

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

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

[0018] Preferably, the dropwise addition time of ethylene oxide in step (5) is 50-60 min.

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

[0020] (3) Beneficial technical effects

[0021] The invention obtains a foaming agent by stirring and mixing fluorine-containing modified pyridine modified carboxyl betaine, sulfonic acid group modified polyoxyethylene ether and methyl isobutyl carbinol.

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

[0023] In fluorine-modified pyridine-modified carboxybetaine, the fluorine atom has high electronegativity and chemical stability, which can enhance the chemical bond strength and overall stability of the foaming agent molecule. During the flotation process, various chemical substances in the pulp and complex environmental conditions may have a certain impact on the foaming agent, and the fluorine-containing foaming agent has good chemical stability and can better resist the influence of these factors, maintain its foaming performance, and thus improve the flotation effect; the sulfur atom forms a stable chelate with the metal ions as a coordinating atom, captures the metal ions from the mineral surface and allows them to enter the solution phase, thereby realizing the separation and purification of the mineral; the pyridine group carries a lone pair of electrons, which can generate electrostatic attraction with the metal cations on the mineral surface to form a hydrophobic film, preventing water molecules from contacting the mineral surface, and further increasing the hydrophobicity of the mineral; the formation of this hydrophobic film helps to improve the adhesion between the bubbles and the mineral, making it easier for the mineral to float to the pulp surface with the bubbles, Enhanced flotation performance; Carboxybetaine is an amphoteric surfactant with carboxyl and cationic groups. When dissolved in water, the polar groups adsorb onto the mineral surface, while the non-polar groups face outward, making the mineral surface hydrophobic. Simultaneously, the intermolecular van der Waals forces strengthen the hydrophobic film on the mineral surface, contributing to flotation. The sulfonic acid groups in sulfonic acid-modified polyoxyethylene ethers adsorb onto the mineral surface, transforming the originally hydrophilic mineral surface into a hydrophobic one. This facilitates the attachment of bubbles to the mineral surface, improving the mineral's floatability and enhancing flotation performance. The polyoxyethylene ether molecular structure contains hydrophilic ether groups and hydrophobic long-chain alkyl groups, enabling the polyoxyethylene ether to adsorb at the gas-liquid interface, thereby reducing the liquid's surface tension and facilitating bubble formation. Furthermore, the polyoxyethylene ether has excellent dispersibility, allowing the frother to be more evenly distributed in the slurry, increasing contact between the frother and the mineral surface, and enabling the mineral to be better captured by the bubbles and floated. The synergistic effect of these multiple groups further enhances the flotation performance of the frother. DETAILED DESCRIPTION

[0024] Example 1

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

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

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

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

[0029] (5) 7 g of sulfonic acid modified initiator and 0.05 g of sodium hydroxide catalyst were added to the reactor, the temperature was raised to 110 ° C, nitrogen was introduced for 25 minutes to replace the air, the temperature was raised to 145 ° C, 12 g of ethylene oxide was added dropwise while stirring, the addition was completed over 50 minutes, and the reaction was kept warm for 4 hours. After the reaction was completed, the sulfonic acid modified polyoxyethylene ether was obtained;

[0030] (6) 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 carbinol were added to a reactor and stirred at 400 rpm for 20 minutes to obtain a foaming agent.

[0031] Example 2

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

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

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

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

[0036] (5) 11 g of sulfonic acid modified initiator and 0.08 g of sodium hydroxide catalyst were added to the reactor, the temperature was raised to 120° C., nitrogen was introduced for 40 min to replace the air, the temperature was raised to 160° C., 15 g of ethylene oxide was added dropwise while stirring, the addition was completed over 60 min, and the reaction was kept warm for 7 h. After the reaction was completed, the sulfonic acid modified polyoxyethylene ether was obtained;

[0037] (6) 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 carbinol were added to a reactor, and the mixture was stirred at 800 rpm for 50 minutes to obtain a foaming agent.

[0038] Example 3

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

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

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

[0042] (4) Add 12 g of sodium bisulfite to deionized water, heat while stirring until the sodium bisulfite dissolves, raise the temperature to 71° C., add 7.5 g of 1,2-epoxydodecane dropwise thereto, complete the addition over 2.2 hours, raise the temperature to 86° C. and keep the temperature for 4.5 hours. After the reaction is completed, cool the reaction solution in an ice-water bath, filter the crystals precipitated after cooling, and recrystallize to obtain a sulfonic acid group-modified initiator;

[0043] (5) 9 g of sulfonic acid modified initiator and 0.065 g of sodium hydroxide catalyst were added to the reactor, the temperature was raised to 115 ° C, nitrogen was introduced for 32 minutes to replace the air, the temperature was raised to 152 ° C, 13.5 g of ethylene oxide was added dropwise while stirring, the addition was completed over 55 minutes, and the reaction was kept warm for 5.5 hours. After the reaction was completed, the sulfonic acid modified polyoxyethylene ether was obtained;

[0044] (6) 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 carbinol were added to a reactor and stirred at 600 rpm for 35 minutes to obtain a foaming agent.

[0045] Example 4

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

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

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

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

[0050] (5) 9 g of sulfonic acid modified initiator and 0.065 g of sodium hydroxide catalyst were added to the reactor, the temperature was raised to 115 ° C, nitrogen was introduced for 32 minutes to replace the air, the temperature was raised to 152 ° C, 13.5 g of ethylene oxide was added dropwise while stirring, the addition was completed over 55 minutes, and the reaction was kept warm for 5.5 hours. After the reaction was completed, the sulfonic acid modified polyoxyethylene ether was obtained;

[0051] (6) 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 carbinol were added to a reactor and stirred at 600 rpm for 35 minutes to obtain a foaming agent.

[0052] Example 5

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

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

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

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

[0057] (5) 7 g of sulfonic acid modified initiator and 0.05 g of sodium hydroxide catalyst were added to the reactor, the temperature was raised to 110 ° C, nitrogen was introduced for 25 minutes to replace the air, the temperature was raised to 145 ° C, 12 g of ethylene oxide was added dropwise while stirring, the addition was completed over 50 minutes, and the reaction was kept warm for 4 hours. After the reaction was completed, the sulfonic acid modified polyoxyethylene ether was obtained;

[0058] (6) 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 carbinol were added to a reactor and stirred at 400 rpm for 20 minutes to obtain a foaming agent.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that no fluorine-modified pyridine-modified carboxybetaine is added in step (6).

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 1 is that no sulfonic acid-modified polyoxyethylene ether is added in step (6).

[0063] Flotation test of copper sulfide ore: A 1 kg sample was crushed to 2 mm. The sample was ground in an SMQ240×90 conical ball mill for 15 minutes at a slurry concentration of 62.5% until a particle size of 0.074 mm (65%) was achieved. Flotation was then performed in an XFD-3L laboratory single-cell flotation cell at a speed of 2070 rpm. The frother dosage was 30 g / t. The test results are shown in Table 1.

[0064] Table 1: Flotation test results of copper sulfide ore:

[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 sulfide lead-zinc ore: A 300g sample was crushed to 2mm. The sample was ground in an SMQ240×90 conical ball mill for 1.5 minutes at a slurry concentration of 60% until a particle size of 0.074mm (70%) was achieved. The ore was then flotated in an XFD-1L laboratory single-cell flotation cell at a speed of 2070 rpm. The frother dosage was 40g / t. The test results are shown in Table 2.

[0067] Table 2: Flotation test results of lead-zinc sulfide ore:

[0068]

[0069] It can be seen from Table 1 and Table 2 that the frothers in Examples 1-5 of the present invention have better flotation effects on minerals than the frothers in Comparative Examples 1-2.

[0070] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present 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 comprises the following steps: (1) Adding 11-17 g of 5,5,5-trifluoropentanol, 10-15 g of 2,6-dichloro-4-mercaptopyridine, and 0.02-0.03 g of sodium hydride catalyst to tetrahydrofuran solvent, stirring and mixing, heating to the reaction temperature and reacting for 3-4 hours. After the reaction is completed, filtering, washing, and drying to obtain fluorine-modified mercaptopyridine; (2) Add 4-8 g of dimethylaminoethyl methacrylate and 12-18 g of 5-bromovaleric acid to anhydrous ethanol solvent, stir and dissolve, then add 0.07-0.09 g of catalyst, introduce nitrogen for 15-35 min to remove oxygen, heat to 32-45 ° C under nitrogen protection and react for 17-20 h. After the reaction is completed, filter, dry at 30-35 ° C for 2-4 h, add deionized water to dissolve, extract with ether and freeze-dry the aqueous phase to obtain a carboxybetaine intermediate; (3) adding 9-13 g of the carboxybetaine intermediate and 6-10 g of fluorine-modified mercaptopyridine to an N,N-dimethylformamide solvent, stirring and mixing, and then adding 0.03-0.05 g of benzoin dimethyl ether photoinitiator thereto, irradiating with 365 nm ultraviolet light at 35-45 ° C. After the reaction is completed, centrifugation, washing and drying are performed to obtain fluorine-modified pyridine-modified carboxybetaine; (4) Add 10-14 g of sodium bisulfite to deionized water, heat while stirring until the sodium bisulfite dissolves, raise the temperature to 68-74 ° C, add 6-9 g of 1,2-epoxydodecane dropwise thereto, and after the addition is complete, raise the temperature to 82-90 ° C and keep the temperature to react for 3-6 hours. After the reaction is completed, cool the reaction solution in an ice water bath, filter the crystals precipitated after cooling, and recrystallize to obtain a sulfonic acid group-modified initiator; (5) Add 7-11 g of sulfonic acid modified initiator and 0.05-0.08 g of catalyst to a reactor, heat to 110-120 ° C, introduce nitrogen for 25-40 min to replace the air, heat to 145-160 ° C, add 12-15 g of ethylene oxide dropwise while stirring, and after the addition is complete, keep warm for 4-7 hours. After the reaction is completed, a 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 carbinol into a 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°C.

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, wherein The ultraviolet light irradiation time in step (3) is 3.5-4h.

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

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: The dropwise addition time of ethylene oxide in step (5) is 50-60 min.

8. The process for preparing the foaming agent according to claim 1, wherein The stirring time in step (6) is 20-50 min.

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