A phosphorus-free composite anti-scaling agent and preparation method thereof

Abstract

The invention relates to the technical field of water treatment, and in particular to a phosphorus-free composite anti-scaling agent and a preparation method thereof, which are used to solve the problem that traditional anti-scaling agents usually contain phosphorus, and although they are widely available and inexpensive, they are not effective under high temperature conditions and are prone to cause eutrophication of water quality, thus exerting a negative impact on the environment. The phosphorus-free composite anti-scaling agent provided by the invention is composed of a specific anti-scaling polymer, an organic acid, a surfactant and an inorganic salt, can effectively prevent the formation of scale under high temperature conditions, has an excellent anti-scaling effect, does not contain phosphorus elements, avoids environmental problems caused by the use of phosphorus-containing anti-scaling agents, such as eutrophication of water quality, and is environmentally friendly. The preparation method of the invention is simple and easy to operate, has mild operating conditions, is pollution-free, does not discharge the three wastes, is safe and environmentally friendly, and is convenient for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a phosphorus-free composite anti-scaling agent and a preparation method thereof. Background Art

[0002] Scaling is one of the common problems in the field of oil and gas production. Insoluble salts such as calcium carbonate and calcium sulfate are deposited on the metal surface of high-temperature heat exchangers (condensers), which will not only block the oil pipes, cause under-scale corrosion, damage the production system, and lead to reduced oil and gas production, but also increase the thermal resistance of the scale, greatly reducing the heat exchange efficiency, thereby causing potential hazards such as energy waste and equipment rupture.

[0003] With the development of industrial production, the scaling problem of circulating water systems under high temperature conditions is becoming increasingly serious. Traditional anti-scaling agents, such as phosphorus-containing polyphosphates and organic phosphonates, although widely available and inexpensive, are not effective under high temperature conditions and are prone to cause eutrophication of water quality, which has a negative impact on the environment. Therefore, the development of a phosphorus-free composite anti-scaling agent and its preparation method is of great practical significance. Summary of the invention

[0004] In order to overcome the above-mentioned technical problems, the purpose of the present invention is to provide a phosphorus-free composite anti-scaling agent and a preparation method thereof: by uniformly mixing an anti-scaling polymer, an organic acid, a surfactant, an inorganic salt and deionized water, a phosphorus-free composite anti-scaling agent is obtained, which solves the problem that traditional anti-scaling agents usually contain phosphorus, which, although widely available and inexpensive, are not effective under high temperature conditions and are prone to cause eutrophication of water quality, which has a negative impact on the environment.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A phosphorus-free composite anti-scaling agent comprises the following components in parts by weight:

[0007] 30-50 parts of anti-scaling polymer, 20-30 parts of organic acid, 15-25 parts of surfactant, 4-10 parts of inorganic salt and 200-250 parts of deionized water;

[0008] Wherein, the anti-fouling polymer is prepared by the following steps:

[0009] Step s1: 3,5-dimethylphenylboronic acid, sodium hydroxide and tert-butanol solution are added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 25-30° C. and a stirring rate of 400-500 r / min for 20-30 min, and then the temperature is raised to 70-75° C. and the stirring reaction is continued for 5-10 min. Potassium permanganate is then added and the stirring reaction is continued for 15-20 h. Sodium sulfite is then added and the stirring reaction is continued for 30-40 min. After the reaction is completed, the reaction product is filtered while hot, and the pH of the filtrate is adjusted to 2-3 with hydrochloric acid solution, and then the precipitate is allowed to stand and precipitate is separated. Then vacuum filtration is performed, and the filter cake is placed in a vacuum drying oven and dried at a temperature of 50-55° C. for 2-3 h to obtain intermediate 1.

[0010] Step s2: 1-nitro-4-(trifluoromethoxy)benzene, dichloromethane and deionized water are added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube, a reflux condenser and a constant pressure dropping funnel, and nitrogen is introduced for protection. The mixture is stirred for reaction for 10-15 minutes at a temperature of 25-30° C. and a stirring rate of 400-500 r / min. Then, liquid bromine is added dropwise while stirring, and the dropping rate is controlled to be 1-2 drops / s. After the dropwise addition is completed, the temperature is raised to reflux and the stirring reaction is continued for 2-3 hours. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation to obtain intermediate 2;

[0011] Step s3: Add intermediate 1, intermediate 2, potassium phosphate, DPPF palladium dichloride and N,N-dimethylformamide to a three-necked flask equipped with a stirrer, a thermometer and an air duct, introduce nitrogen protection, stir the reaction at a temperature of 25-30°C and a stirring rate of 400-500r / min for 20-30min, then heat the temperature to 75-80°C and continue stirring the reaction for 10-12h. After the reaction is completed, cool the reaction product to room temperature, then add it to distilled water, then extract it with ethyl acetate 2-3 times, combine the extracts and dry the extracts with anhydrous sodium sulfate, then vacuum filter, and rotary evaporate the filtrate to remove the solvent to obtain intermediate 3;

[0012] Step s4: Add intermediate 3, 10% palladium carbon and anhydrous ethanol to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, introduce hydrogen to maintain the pressure at 2.1-2.3 MPa, then stir the reaction at a temperature of 25-30°C and a stirring rate of 400-500 r / min for 20-30 min, then heat to reflux and continue stirring the reaction for 2-3 h. After the reaction is completed, cool the reaction product to room temperature, then vacuum filter, and rotary evaporate the filtrate to remove the solvent to obtain intermediate 4;

[0013] Step s5: Add intermediate 4, sodium carbonate and anhydrous ethanol to a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel, stir and react for 10-15 minutes at a temperature of 25-30°C and a stirring rate of 400-500r / min, then heat to 55-60°C and continue stirring and reacting for 25-30 minutes, then add allyl bromide dropwise while stirring, control the dropping rate to 1-2 drops / s, and after the dropwise addition is completed, heat to reflux and continue stirring and reacting for 4-5 hours. After the reaction is completed, add the reaction product to a hydrochloric acid solution to precipitate, then vacuum filter, place the filter cake in a vacuum drying oven, and dry it at a temperature of 40-45°C for 3-4 hours to obtain intermediate 5;

[0014] Step s6: Add intermediate 5, vinyltriethoxysilane and N,N-dimethylformamide to a three-necked flask equipped with a stirrer, a thermometer, an air duct and a constant pressure dropping funnel, introduce nitrogen protection, stir and react for 20-30 minutes at a temperature of 25-30°C and a stirring rate of 400-500r / min, then raise the temperature to 65-70°C and add azobisisobutyronitrile solution dropwise while stirring, control the dropping rate to 1-2 drops / s, and after the addition is completed, raise the temperature to 90-95°C and continue stirring and reacting for 4-5 hours. After the reaction is completed, cool the reaction product to room temperature, then rotary evaporate to remove the solvent, and then recrystallize with isopropanol to obtain an anti-fouling polymer.

[0015] As a further solution of the present invention: the usage ratio of the 3,5-dimethylbenzeneboronic acid, sodium hydroxide, tert-butanol solution, potassium permanganate and sodium sulfite in step s1 is 10 mmol: 25-30 mmol: 80-100 mL: 10-12 g: 5-6 g.

[0016] As a further solution of the present invention: the tert-butanol solution in step s1 is a mixture of tert-butanol and deionized water in equal volumes, and the mass fraction of the hydrochloric acid solution is 15-20%.

[0017] As a further solution of the present invention: the usage ratio of the 1-nitro-4-(trifluoromethoxy)benzene, dichloromethane, deionized water and liquid bromine in step s2 is 10 mmol:40-45 mL:10-15 mL:25-30 mmol.

[0018] As a further scheme of the present invention: the usage ratio of the intermediate 1, intermediate 2, potassium phosphate, DPPF palladium dichloride and N,N-dimethylformamide in step s3 is 30-35mmol:10mmol:35-40mmol:1-1.2g:60-70mL.

[0019] As a further solution of the present invention: the usage ratio of the intermediate 3, 10% palladium carbon and anhydrous ethanol in step s4 is 5g:0.8-1.6g:80-100mL.

[0020] As a further solution of the present invention: the usage ratio of the intermediate 4, sodium carbonate, anhydrous ethanol and allyl bromide in step s5 is 10mmol:15-20mmol:100-120mL:11-13mmol, and the mass fraction of the hydrochloric acid solution is 15-20%.

[0021] As a further solution of the present invention: the usage ratio of the intermediate 5, vinyltriethoxysilane, N,N-dimethylformamide and azobisisobutyronitrile solution in step s6 is 10 mmol: 10 mmol: 100-120 mL: 10-15 mL.

[0022] As a further solution of the present invention: the azobisisobutyronitrile solution in step s6 is a solution formed by dissolving azobisisobutyronitrile in N,N-dimethylformamide at a ratio of 0.2-0.3 g:10 mL.

[0023] As a further solution of the present invention: a method for preparing a phosphorus-free composite anti-scaling agent comprises the following steps:

[0024] Step 1: Weigh 30-50 parts of anti-scaling polymer, 20-30 parts of organic acid, 15-25 parts of surfactant, 4-10 parts of inorganic salt and 200-250 parts of deionized water according to weight parts for later use; the organic acid is one of citric acid and tartaric acid; the surfactant is one of Tween 20 and Span 80; the inorganic salt is one of magnesium sulfate, zinc sulfonate and sodium sulfate;

[0025] Step 2: Evenly mix the anti-scaling polymer, organic acid, surfactant, inorganic salt and deionized water to obtain a phosphorus-free composite anti-scaling agent.

[0026] Beneficial effects of the present invention:

[0027] The invention discloses a phosphorus-free composite anti-scaling agent and a preparation method thereof. The phosphorus-free composite anti-scaling agent is obtained by uniformly mixing an anti-scaling polymer, an organic acid, a surfactant, an inorganic salt and deionized water. The phosphorus-free composite anti-scaling agent provided by the invention is composed of a specific anti-scaling polymer, an organic acid, a surfactant and an inorganic salt, can effectively prevent the formation of scale under high temperature conditions, has an excellent anti-scaling effect, does not contain phosphorus elements, avoids environmental problems caused by the use of phosphorus-containing anti-scaling agents, such as water eutrophication, etc., and is environmentally friendly. The preparation method of the invention is simple and easy to operate, has mild operating conditions, is pollution-free, does not discharge the three wastes, is safe and environmentally friendly, and is convenient for industrial production.

[0028] In the process of preparing the phosphorus-free composite anti-scaling agent, an anti-scaling polymer is first prepared. First, 3,5-dimethylbenzeneboronic acid and potassium permanganate are used to react. The methyl group on the 3,5-dimethylbenzeneboronic acid is oxidized to a carboxyl group by potassium permanganate to obtain intermediate 1. Then, 1-nitro-4-(trifluoromethoxy)benzene and liquid bromine are used to react. Multiple bromine atoms are introduced into the benzene ring of 1-nitro-4-(trifluoromethoxy)benzene to obtain intermediate 2. Then, intermediate 1 and intermediate 2 are reacted. The boric acid group on intermediate 1 and the bromine on intermediate 2 are reacted. Atomic reaction is carried out to introduce a large number of carboxyl groups on the benzene ring to obtain intermediate 3. Then, the nitro group of intermediate 3 is reduced to amino group under hydrogen to obtain intermediate 4. Then, intermediate 4 reacts with allyl bromide, and the amino group on intermediate 4 reacts with the bromine atom on allyl bromide to introduce alkenyl groups to obtain intermediate 5. Finally, intermediate 5 and vinyl triethoxysilane are used as polymerization monomers to form an anti-fouling polymer through polymerization reaction. The molecular structure of the anti-fouling polymer contains a large number of carboxyl groups, which can react with Ca in water. 2+ Mg 2+ , Fe 3+ , Cu 2+ The anti-scaling polymer can form stable chelates with metal ions such as carbonate, thereby reducing the possibility of metal ions combining with anions such as carbonate to form scale, and can also ionize carboxylate anions in water. These anions will be attracted by opposite charges with the positive charges on the surface of the scale and adsorbed on the surface of the scale micro-crystals to form a protective film to prevent the scale from continuing to grow; the molecular structure of the anti-scaling polymer also contains a large number of siloxy groups. After the siloxy groups are introduced into the anti-scaling agent molecules, they can be hydrolyzed to form silanols. The silanols can form coordination bonds with the metal surface to inhibit scaling on the metal surface, and the introduced organic silicon can also effectively improve its high temperature resistance; the molecular structure of the anti-scaling polymer also contains a large number of CF bonds, and the CF bonds are highly stable, which further improves its high temperature resistance; therefore, the anti-scaling polymer has good anti-scaling effect and excellent high temperature resistance, so that it can still effectively prevent the formation of scale under high temperature conditions and has excellent anti-scaling effect. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0030] This embodiment is a method for preparing a phosphorus-free composite anti-scaling agent, comprising the following steps:

[0031] Step S1: 10mmol 3,5-dimethylphenylboronic acid, 25mmol sodium hydroxide, 80mL tert-butanol and deionized water are mixed in equal volumes to prepare a tert-butanol solution, which is added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen is introduced for protection. The mixture is stirred and reacted for 20min at a temperature of 25°C and a stirring rate of 400r / min, and then the mixture is heated to 70°C and stirred and reacted for 5min, and then 10g potassium permanganate is added and stirred and reacted for 15h, and then 5g sodium sulfite is added and stirred and reacted for 30min. After the reaction is completed, the reaction product is filtered while hot, and then the filtrate is adjusted to pH 2 with a hydrochloric acid solution having a mass fraction of 15%, and then the precipitate is allowed to stand and precipitate is precipitated, and then vacuum filtered, and the filter cake is placed in a vacuum drying oven and dried at a temperature of 50°C for 2h to obtain an intermediate 1;

[0032] Step S2: 10 mmol 1-nitro-4-(trifluoromethoxy)benzene, 40 mL dichloromethane and 10 mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube, a reflux condenser and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 25° C. and a stirring rate of 400 r / min for 10 min, and then 25 mmol liquid bromine was added dropwise while stirring, and the dropping rate was controlled to be 1 drop / s. After the addition was completed, the temperature was raised to reflux and the stirring reaction was continued for 2 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation to obtain intermediate 2;

[0033] Step S3: 30mmol of intermediate 1, 10mmol of intermediate 2, 35mmol of potassium phosphate, 1g of DPPF palladium dichloride and 60mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred at 25°C and a stirring rate of 400r / min for 20min, and then the mixture was heated to 75°C and the stirring reaction was continued for 10h. After the reaction was completed, the reaction product was cooled to room temperature, and then added to distilled water, and then extracted with ethyl acetate twice, the extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent to obtain intermediate 3;

[0034] Step S4: 5 g of intermediate 3, 0.8 g of 10% palladium carbon and 80 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, and hydrogen was introduced to maintain the pressure at 2.1 MPa. Then, the mixture was stirred for reaction at 25° C. and a stirring rate of 400 r / min for 20 min, and then the mixture was heated to reflux and continued to stir for 2 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent to obtain intermediate 4;

[0035] Step S5: 10 mmol of intermediate 4, 15 mmol of sodium carbonate and 100 mL of anhydrous ethanol were added to a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel, and stirred for reaction at a temperature of 25°C and a stirring rate of 400 r / min for 10 min, then heated to 55°C and continued to stir for 25 min, then 11 mmol of allyl bromide was added dropwise while stirring, and the dropping rate was controlled to be 1 drop / s. After the dropwise addition was completed, the temperature was raised to reflux and continued to stir for 4 h. After the reaction was completed, the reaction product was added to a hydrochloric acid solution with a mass fraction of 15% to precipitate, and then vacuum filtered, and the filter cake was placed in a vacuum drying oven and dried at a temperature of 40°C for 3 h to obtain intermediate 5;

[0036] Step S6: 10 mmol of intermediate 5, 10 mmol of vinyl triethoxysilane and 100 mL of N, N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 25°C and a stirring rate of 400 r / min for 20 min. Then, the mixture was heated to 65°C and 10 mL of azobisisobutyronitrile was dissolved in N, N-dimethylformamide at a ratio of 0.2 g:10 mL, and azobisisobutyronitrile solution was added dropwise while stirring. The dropping rate was controlled to be 1 drop / s. After the addition was completed, the mixture was heated to 90°C and continued to stir for 4 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. Then, the mixture was recrystallized with isopropanol to obtain an anti-fouling polymer.

[0037] Step S7: weigh 30 parts of anti-scaling polymer, 20 parts of organic acid, 15 parts of surfactant, 4 parts of inorganic salt and 200 parts of deionized water according to weight parts for later use; the organic acid is citric acid; the surfactant is Tween 20; the inorganic salt is magnesium sulfate;

[0038] Step S8: uniformly mix the anti-scaling polymer, organic acid, surfactant, inorganic salt and deionized water to obtain a phosphorus-free composite anti-scaling agent. Example

[0039] This embodiment is a method for preparing a phosphorus-free composite anti-scaling agent, comprising the following steps:

[0040] Step S1: 10mmol 3,5-dimethylphenylboronic acid, 28mmol sodium hydroxide, 90mL tert-butanol and deionized water were mixed in equal volumes to prepare a tert-butanol solution, which was added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 28°C and a stirring rate of 450r / min for 25min, and then the mixture was heated to 72°C and stirred for reaction for 8min, and then 11g potassium permanganate was added and stirred for reaction for 18h, and then 5.5g sodium sulfite was added and stirred for reaction for 35min. After the reaction was completed, the reaction product was filtered while hot, and then the filtrate was adjusted to pH 2.5 with a hydrochloric acid solution having a mass fraction of 18%, and then the filtrate was allowed to stand for precipitation, and then vacuum filtered. The filter cake was placed in a vacuum drying oven and dried at a temperature of 52°C for 2.5h to obtain an intermediate 1;

[0041] Step S2: 10 mmol 1-nitro-4-(trifluoromethoxy)benzene, 42 mL dichloromethane and 12 mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube, a reflux condenser and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred for 12 min at a temperature of 28° C. and a stirring rate of 450 r / min. Then, 28 mmol liquid bromine was added dropwise while stirring, and the dropping rate was controlled to be 1 drop / s. After the addition was completed, the temperature was raised to reflux and the stirring reaction was continued for 2.5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation to obtain intermediate 2;

[0042] Step S3: 32 mmol of intermediate 1, 10 mmol of intermediate 2, 38 mmol of potassium phosphate, 1.1 g of DPPF palladium dichloride and 65 mL of N, N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred at 28° C. and a stirring rate of 450 r / min for 25 min, and then the mixture was heated to 78° C. and the stirring reaction was continued for 11 h. After the reaction was completed, the reaction product was cooled to room temperature, and then added to distilled water, and then extracted with ethyl acetate twice, the extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent to obtain intermediate 3;

[0043] Step S4: 5 g of intermediate 3, 1.2 g of 10% palladium carbon and 90 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, and hydrogen was introduced to maintain the pressure at 2.2 MPa. Then, the reaction was stirred at a temperature of 28° C. and a stirring rate of 450 r / min for 25 min, and then the temperature was raised to reflux and the stirring reaction was continued for 2.5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent to obtain intermediate 4;

[0044] Step S5: 10 mmol of intermediate 4, 18 mmol of sodium carbonate and 110 mL of anhydrous ethanol were added to a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel, and stirred for reaction at a temperature of 28° C. and a stirring rate of 450 r / min for 12 min, then heated to 58° C. and continued to stir for 28 min, then added dropwise with stirring 12 mmol of allyl bromide, and the dropping rate was controlled to be 2 drops / s. After the dropwise addition was completed, the temperature was raised to reflux and continued to stir for 4.5 h. After the reaction was completed, the reaction product was added to a hydrochloric acid solution with a mass fraction of 18% to precipitate, and then vacuum filtered. The filter cake was placed in a vacuum drying oven and dried at a temperature of 42° C. for 3.5 h to obtain intermediate 5;

[0045] Step S6: 10 mmol of intermediate 5, 10 mmol of vinyl triethoxysilane and 110 mL of N, N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 28°C and a stirring rate of 450 r / min for 25 min. Then, the mixture was heated to 68°C and 12 mL of azobisisobutyronitrile was dissolved in N, N-dimethylformamide at a ratio of 0.25 g:10 mL and dropwise added with stirring. The dropping rate was controlled to be 1 drop / s. After the addition was completed, the mixture was heated to 92°C and continued to stir for 4.5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. The mixture was then recrystallized with isopropanol to obtain an anti-fouling polymer.

[0046] Step S7: 40 parts of anti-scaling polymer, 25 parts of organic acid, 20 parts of surfactant, 7 parts of inorganic salt and 225 parts of deionized water are weighed in parts by weight for later use; the organic acid is citric acid; the surfactant is Span 80; the inorganic salt is zinc sulfonate;

[0047] Step S8: uniformly mix the anti-scaling polymer, organic acid, surfactant, inorganic salt and deionized water to obtain a phosphorus-free composite anti-scaling agent. Example

[0048] This embodiment is a method for preparing a phosphorus-free composite anti-scaling agent, comprising the following steps:

[0049] Step S1: Add 10mmol 3,5-dimethylphenylboronic acid, 30mmol sodium hydroxide, 100mL tert-butanol and deionized water in equal volumes to form a tert-butanol solution into a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introduce nitrogen protection, stir and react for 30min at a temperature of 30°C and a stirring rate of 500r / min, then heat to 75°C and continue stirring and reacting for 10min, then add 12g potassium permanganate and continue stirring and reacting for 20h, then add 6g sodium sulfite and continue stirring and reacting for 40min, after the reaction is completed, filter the reaction product while hot, then adjust the pH of the filtrate to 3 with a 20% hydrochloric acid solution by mass fraction, then stand and precipitate, then vacuum filter, place the filter cake in a vacuum drying oven, and dry it at a temperature of 55°C for 3h to obtain intermediate 1;

[0050] Step S2: 10 mmol 1-nitro-4-(trifluoromethoxy)benzene, 45 mL dichloromethane and 15 mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube, a reflux condenser and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 30° C. and a stirring rate of 500 r / min for 15 min, and then 30 mmol liquid bromine was added dropwise while stirring, and the dropping rate was controlled to be 2 drops / s. After the addition was completed, the temperature was raised to reflux and the stirring reaction was continued for 3 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation to obtain intermediate 2;

[0051] Step S3: 35mmol of intermediate 1, 10mmol of intermediate 2, 0mmol of potassium phosphate, 1.2g of DPPF palladium dichloride and 70mL of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred at 30°C and a stirring rate of 500r / min for 30min, and then the mixture was heated to 80°C and the stirring reaction was continued for 12h. After the reaction was completed, the reaction product was cooled to room temperature, and then added to distilled water, and then extracted with ethyl acetate for 3 times. The extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain intermediate 3;

[0052] Step S4: 5 g of intermediate 3, 1.6 g of 10% palladium carbon and 100 mL of anhydrous ethanol were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube and a reflux condenser, and hydrogen was introduced to maintain the pressure at 2.3 MPa. Then, the reaction was stirred for 30 min at a temperature of 30 ° C and a stirring rate of 500 r / min, and then the temperature was raised to reflux and the stirring reaction was continued for 3 h. After the reaction was completed, the reaction product was cooled to room temperature, and then vacuum filtered, and the filtrate was rotary evaporated to remove the solvent to obtain intermediate 4;

[0053] Step S5: 10 mmol of intermediate 4, 20 mmol of sodium carbonate and 120 mL of anhydrous ethanol were added to a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a constant pressure dropping funnel, and stirred for reaction at a temperature of 30°C and a stirring rate of 500 r / min for 15 min, then heated to 60°C and continued to stir for reaction for 30 min, then 13 mmol of allyl bromide was added dropwise while stirring, and the dropping rate was controlled to be 2 drops / s. After the dropwise addition was completed, the temperature was raised to reflux and continued to stir for reaction for 5 h. After the reaction was completed, the reaction product was added to a hydrochloric acid solution with a mass fraction of 20% to precipitate, and then vacuum filtered, and the filter cake was placed in a vacuum drying oven and dried at a temperature of 45°C for 4 h to obtain intermediate 5;

[0054] Step S6: 10 mmol of intermediate 5, 10 mmol of vinyl triethoxysilane and 120 mL of N, N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred for 30 min at a temperature of 30°C and a stirring rate of 500 r / min. Then, the mixture was heated to 70°C and 15 mL of azobisisobutyronitrile was added dropwise while stirring. The azobisisobutyronitrile solution formed by dissolving the azobisisobutyronitrile in N, N-dimethylformamide at a ratio of 0.3 g:10 mL was added. The dropping rate was controlled to be 2 drops / s. After the addition was completed, the mixture was heated to 95°C and the stirring reaction was continued for 5 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. The mixture was then recrystallized with isopropanol to obtain an anti-fouling polymer.

[0055] Step S7: weigh 50 parts of anti-scaling polymer, 30 parts of organic acid, 25 parts of surfactant, 10 parts of inorganic salt and 250 parts of deionized water according to weight parts for later use; the organic acid is tartaric acid; the surfactant is Span 80; the inorganic salt is sodium sulfate;

[0056] Step S8: uniformly mix the anti-scaling polymer, organic acid, surfactant, inorganic salt and deionized water to obtain a phosphorus-free composite anti-scaling agent.

[0057] Comparative Example 1:

[0058] This comparative example is a method for preparing a phosphorus-free composite anti-scaling agent, comprising the following steps:

[0059] Step S7: weigh 30 parts of organic acid, 25 parts of surfactant, 10 parts of inorganic salt and 250 parts of deionized water according to weight parts for later use; the organic acid is tartaric acid; the surfactant is Span 80; the inorganic salt is sodium sulfate;

[0060] Step S8: uniformly mix the organic acid, surfactant, inorganic salt and deionized water to obtain a phosphorus-free composite anti-scaling agent.

[0061] Comparative Example 2:

[0062] This comparative example is a method for preparing a phosphorus-free composite anti-scaling agent, comprising the following steps:

[0063] Step S1: weigh 50 parts of polymaleic acid, 30 parts of organic acid, 25 parts of surfactant, 10 parts of inorganic salt and 250 parts of deionized water according to weight parts for later use; the molecular weight of the polymaleic acid is 5 million; the organic acid is tartaric acid; the surfactant is Span 80; the inorganic salt is sodium sulfate;

[0064] Step S2: uniformly mix polymaleic acid, organic acid, surfactant, inorganic salt and deionized water to obtain a phosphorus-free composite anti-scaling agent.

[0065] Comparative Example 3:

[0066] This comparative example is a method for preparing a phosphorus-free composite anti-scaling agent, comprising the following steps:

[0067] Step S1: 10 mmol maleic anhydride, 10 mmol vinyl triethoxysilane and 120 mL N, N-dimethylformamide are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen is introduced for protection. The mixture is stirred for reaction at a temperature of 30° C. and a stirring rate of 500 r / min for 30 min. Then, the mixture is heated to 70° C. and 15 mL of azobisisobutyronitrile solution prepared by dissolving the mixture in N, N-dimethylformamide at a ratio of 0.3 g:10 mL is added dropwise while stirring. The dropping rate is controlled to be 2 drops / s. After the addition is completed, the mixture is heated to 95° C. and the stirring reaction is continued for 5 h. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation, and then recrystallized with isopropanol to obtain an anti-fouling polymer.

[0068] Step S2: weigh 50 parts of anti-scaling polymer, 30 parts of organic acid, 25 parts of surfactant, 10 parts of inorganic salt and 250 parts of deionized water according to weight parts for later use; the organic acid is tartaric acid; the surfactant is Span 80; the inorganic salt is sodium sulfate;

[0069] Step S3: uniformly mix the anti-scaling polymer, organic acid, surfactant, inorganic salt and deionized water to obtain a phosphorus-free composite anti-scaling agent.

[0070] The performance of the phosphorus-free composite anti-scaling agent of Examples 1-3 and Comparative Examples 1-3 was tested in the following manner:

[0071] Prepare a solution containing an anti-scaling agent: add 250 mL of water to a 500 mL volumetric flask, add 0.15 mol / L of calcium chloride solution with a burette until the amount of calcium ions is 120 mg, then add the phosphorus-free composite anti-scaling agent of Examples 1-3 and Comparative Examples 1-3 respectively, and control the addition amount to 100 mg / L, then add 20 mL of a pH=9 borax buffer solution, and then add 3.0 mol / L NaHCO3 solution with a burette to make the amount of carbonate ions in the solution reach 366 mg, and finally dilute to the scale with water and shake well.

[0072] Prepare blank solution: add 250mL of water to a 500mL volumetric flask, add 0.15mol / L calcium chloride solution with a burette until the amount of calcium ions is 120mg, then add 20mL of pH=9 borax buffer solution, then add 3.0mol / L NaHCO3 solution with a burette to make the amount of carbonate ions in the solution reach 366mg, finally dilute to the scale with water and shake well.

[0073] The solution containing the anti-scaling agent and the blank solution were kept at 80°C for 10 hours and filtered while hot. The calcium ion concentration of the filtrate was then tested and the anti-scaling rate η was calculated. The calculation method of the anti-scaling rate η is as follows:

[0074]

[0075] Where:

[0076] ρ is the calcium ion concentration in the blank solution, mg / mL;

[0077] ρ1 is the calcium ion concentration in the blank solution after incubation, mg / mL;

[0078] ρ2 is the calcium ion concentration in the solution containing the anti-scaling agent after insulation, mg / mL.

[0079] The test results are shown in the following table:

[0080]

[0081] Referring to the data in the above table, based on the comparison between Examples 1-3 and Comparative Examples 1-3, it can be known that the phosphorus-free composite anti-scaling agent of the present invention has excellent anti-scaling performance.

[0082] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0083] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A phosphorus-free composite anti-scaling agent, characterized in that: It comprises the following components in parts by weight: 30-50 parts of anti-scaling polymer, 20-30 parts of organic acid, 15-25 parts of surfactant, 4-10 parts of inorganic salt and 200-250 parts of deionized water; the organic acid is one of citric acid and tartaric acid; the surfactant is one of Tween 20 and Span80; the inorganic salt is one of magnesium sulfate, zinc sulfonate and sodium sulfate; Wherein, the anti-fouling polymer is prepared by the following steps: Step s1: 3,5-dimethylphenylboronic acid, sodium hydroxide and tert-butanol solution are stirred for reaction, and then potassium permanganate and sodium sulfite are added to continue stirring for reaction. After the reaction is completed, the reaction product is filtered while hot, and then the pH of the filtrate is adjusted with hydrochloric acid solution, and then the filtrate is allowed to stand for precipitation, and then vacuum filtered, and the filter cake is dried to obtain intermediate 1; Step s2: 1-nitro-4-(trifluoromethoxy)benzene, dichloromethane and deionized water are stirred for reaction, and then liquid bromine is added dropwise while stirring. After the addition is completed, the stirring reaction is continued. After the reaction is completed, the reaction product is cooled and then rotary evaporated to obtain intermediate 2; Step s3: Stir and react the intermediate 1, intermediate 2, potassium phosphate, DPPF palladium dichloride and N,N-dimethylformamide. After the reaction, add the reaction product into distilled water, extract it, dry the extract, vacuum filter it, and rotary evaporate the filtrate to obtain the intermediate 3. Step s4: reacting the intermediate 3, 10% palladium carbon and anhydrous ethanol with stirring under the condition of passing hydrogen gas, cooling the reaction product after the reaction is completed, and then vacuum filtering, and rotary evaporating the filtrate to obtain the intermediate 4; Step s5: stirring the intermediate 4, sodium carbonate and anhydrous ethanol for reaction, then adding allyl bromide dropwise while stirring, and continuing to stir the reaction after the addition is complete. After the reaction is complete, adding the reaction product to a hydrochloric acid solution to precipitate, and then vacuum filtering, and drying the filter cake to obtain the intermediate 5; Step s6: Stir the intermediate 5, vinyltriethoxysilane and N,N-dimethylformamide for reaction, then add the azobisisobutyronitrile solution dropwise while stirring, continue stirring the reaction after the addition is complete, cool the reaction product after the reaction is completed, then rotary evaporate, and then recrystallize with isopropanol to obtain an anti-fouling polymer.

2. A phosphorus-free composite anti-scaling agent according to claim 1, characterized in that: The usage ratio of the 3,5-dimethylbenzeneboric acid, sodium hydroxide, tert-butanol solution, potassium permanganate and sodium sulfite in step s1 is 10 mmol: 25-30 mmol: 80-100 mL: 10-12 g: 5-6 g.

3. A phosphorus-free composite anti-scaling agent according to claim 1, characterized in that: The tert-butanol solution in step s1 is a mixture of tert-butanol and deionized water in equal volumes, and the mass fraction of the hydrochloric acid solution is 15-20%.

4. A phosphorus-free composite anti-scaling agent according to claim 1, characterized in that: The usage ratio of the 1-nitro-4-(trifluoromethoxy)benzene, dichloromethane, deionized water and liquid bromine in step s2 is 10 mmol:40-45 mL:10-15 mL:25-30 mmol.

5. A phosphorus-free composite anti-scaling agent according to claim 1, characterized in that: The usage ratio of the intermediate 1, intermediate 2, potassium phosphate, DPPF palladium dichloride and N,N-dimethylformamide in step s3 is 30-35mmol:10mmol:35-40mmol:1-1.2g:60-70mL.

6. A phosphorus-free composite anti-scaling agent according to claim 1, characterized in that: The usage ratio of the intermediate 3, 10% palladium carbon and anhydrous ethanol in step s4 is 5g:0.8-1.6g:80-100mL.

7. The phosphorus-free composite anti-scaling agent according to claim 1, characterized in that: The usage ratio of the intermediate 4, sodium carbonate, anhydrous ethanol and allyl bromide in step s5 is 10mmol:15-20mmol:100-120mL:11-13mmol, and the mass fraction of the hydrochloric acid solution is 15-20%.

8. The phosphorus-free composite antiscalant according to claim 1, characterized in that: The usage ratio of the intermediate 5, vinyltriethoxysilane, N,N-dimethylformamide and azobisisobutyronitrile solution in step s6 is 10 mmol: 10 mmol: 100-120 mL: 10-15 mL.

9. The phosphorus-free composite anti-scaling agent according to claim 1, characterized in that: The azobisisobutyronitrile solution in step s6 is a solution formed by dissolving azobisisobutyronitrile in N,N-dimethylformamide at a ratio of 0.2-0.3 g:10 mL.

10. A method for preparing the phosphorus-free composite anti-scaling agent according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Weigh 30-50 parts of anti-scaling polymer, 20-30 parts of organic acid, 15-25 parts of surfactant, 4-10 parts of inorganic salt and 200-250 parts of deionized water according to weight parts for later use; the organic acid is one of citric acid and tartaric acid; the surfactant is one of Tween 20 and Span 80; the inorganic salt is one of magnesium sulfate, zinc sulfonate and sodium sulfate; Step 2: Evenly mix the anti-scaling polymer, organic acid, surfactant, inorganic salt and deionized water to obtain a phosphorus-free composite anti-scaling agent.