Composition for preparing scale inhibitor, scale inhibitor, preparation method and application thereof

Abstract

The present invention provides a composition for preparing a scale inhibitor, a scale inhibitor, a preparation method thereof, and an application thereof, belonging to the field of water treatment technology. The composition comprises maleic anhydride, acrylic acid, a sulfonic acid anion monomer, a first functional monomer, a second functional monomer, an initiator, and water; raw materials for preparing the first functional monomer include 5-aminoorotic acid, a first solvent, pyridine, and maleic anhydride; and raw materials for preparing the second functional monomer include 1,2-benzisothiazolin-3-one, ethyl chloroacetate, a second solvent, and hydrazine hydrate. The scale inhibitor provided by the present invention has high scale inhibition efficiency, good corrosion inhibition effect, and excellent antibacterial properties.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a composition for preparing a scale inhibitor, the scale inhibitor, and a preparation method and application thereof. Background Art

[0002] With the development of society, the proportion of industrial water consumption is increasing. It plays a crucial role in manufacturing, processing, purification, and cooling, and is often called the lifeblood of industry. According to statistics, industrial water accounts for 35-40% of my country's total water use, with cooling water accounting for over 80% of this total. Recycling cooling water can conserve water resources. However, long-term cooling water recycling can lead to scaling on pipe surfaces, metal corrosion, and microbial growth due to evaporation and concentration, as well as increases in pH and temperature. Therefore, post-circulation cooling water treatment is essential.

[0003] The most commonly used cooling water treatment method is to add scale inhibitors to the cooling water. However, the existing scale inhibitors have the problems of low scale inhibition efficiency, poor corrosion inhibition effect, and poor antibacterial performance. Therefore, there is an urgent need to provide a scale inhibitor with high scale inhibition efficiency, good corrosion inhibition effect, and excellent antibacterial performance. Summary of the Invention

[0004] In response to one or more technical problems existing in the prior art, the present invention provides a composition for preparing a scale inhibitor, a scale inhibitor, and a preparation method and application thereof. The scale inhibitor provided by the present invention has high scale inhibition efficiency, good corrosion inhibition effect, and excellent antibacterial performance.

[0005] In a first aspect, the present invention provides a composition for preparing a scale inhibitor, the composition comprising maleic anhydride, acrylic acid, a sulfonic acid anion monomer, a first functional monomer, a second functional monomer, an initiator, and water;

[0006] The raw materials for preparing the first functional monomer include 5-aminoorotic acid, a first solvent, pyridine and maleic anhydride;

[0007] The raw materials for preparing the second functional monomer include 1,2-benzisothiazolin-3-one, ethyl chloroacetate, a second solvent and hydrazine hydrate.

[0008] Preferably, the composition comprises, by weight, 100-120 parts of maleic anhydride, 70-90 parts of acrylic acid, 20-30 parts of sulfonic acid anionic monomer, 15-30 parts of first functional monomer, 15-30 parts of second functional monomer, 0.2-0.4 parts of initiator and 550-650 parts of water.

[0009] Preferably, the molar ratio of 5-aminoorotic acid, maleic anhydride and pyridine is 1:(1.2-1.5):(1.1-1.3);

[0010] The mass ratio of 5-aminoorotic acid to the first solvent is (1-1.3):15.

[0011] Preferably, the molar ratio of 1,2-benzisothiazolin-3-one, ethyl chloroacetate and hydrazine hydrate is 1:(1.1-1.3):(1.1-1.3);

[0012] The mass ratio of the 1,2-benzisothiazolin-3-one to the second solvent is (1-1.3):10.

[0013] Preferably, the sulfonic acid anion monomer is at least one of allyl sulfonic acid and vinyl sulfonic acid;

[0014] The initiator is an azo initiator, and the azo initiator is one or more of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobisisoheptanenitrile, and azobisisobutyronitrile, preferably azobisisobutylamidine hydrochloride;

[0015] The first solvent is dichloromethane;

[0016] The second solvent is ethanol; and / or

[0017] The hydrazine hydrate contains 85% hydrazine.

[0018] In a second aspect, the present invention provides a scale inhibitor, wherein the raw materials for preparing the scale inhibitor include the composition described in the first aspect.

[0019] The present invention provides a third aspect of a method for preparing the scale inhibitor according to the second aspect, the method comprising the following steps:

[0020] S1. The maleic anhydride, acrylic acid, sulfonic acid anionic monomer and water are thoroughly mixed and the pH is adjusted to 5.5 to 6.5 to obtain a blend;

[0021] S2. Add the first functional monomer and the second functional monomer to the blend, mix well, perform a first nitrogen deoxygenation, raise the temperature to 45-50° C. under a protective atmosphere, add an initiator to initiate a polymerization reaction, and obtain the scale inhibitor.

[0022] Preferably, the preparation method of the first functional monomer comprises: mixing 5-aminoorotic acid and a first solvent, performing a second nitrogen purge to remove oxygen, adding pyridine for activation treatment, then adding maleic anhydride, performing a first reaction, and recrystallizing to obtain the first functional monomer;

[0023] Preferably, the second nitrogen deoxygenation time is 30 to 40 minutes;

[0024] Preferably, the activation treatment temperature is 20-30°C and the time is 2-3 hours;

[0025] Preferably, the first reaction is carried out under nitrogen protection, the reaction temperature is 40-50° C., and the reaction time is 2-5 hours.

[0026] Preferably, the preparation method of the second functional monomer comprises: uniformly mixing 1,2-benzisothiazolin-3-one, ethyl chloroacetate and a second solvent at room temperature, then adding hydrazine hydrate, conducting a second reaction until the precipitate no longer increases, and filtering to obtain the second functional monomer.

[0027] The third aspect of the present invention provides use of the scale inhibitor described in the second aspect in water treatment.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] The acrylic acid and maleic anhydride copolymer in the composition of the present invention can dissociate into negative ions in an aqueous solution. When these negative ions collide with calcium carbonate microcrystals in the aqueous solution, they undergo physical and chemical adsorption, forming a charge-receiving layer on the surface of the calcium carbonate microcrystals. When the polymer negative ions adsorb the calcium carbonate microcrystals, they impart the same charge. The electrostatic repulsion between the charged calcium carbonate microcrystals prevents collisions between them to form large crystals, keeping them in a very small particle state, increasing the contact area between the crystals and water, and thus improving the crystal solubility. Furthermore, the electrostatic repulsion between the charged calcium carbonate microcrystals prevents collisions between them and metal heat transfer surfaces, reducing the number of crystal nuclei that can form scale layers and effectively inhibiting scale formation.

[0030] The first functional monomer of the present invention is prepared using 5-aminoorotic acid, a solvent, pyridine and maleic anhydride as raw materials. The heteroatoms in the molecular structure can be well adsorbed on the surface of carbon steel to form an anti-corrosion film, which can effectively prevent the reaction of interfacial ions, inhibit the aggregation of scale crystal nuclei on the surface of the pipeline, and improve the corrosion inhibition performance of the polymer.

[0031] The second functional monomer of the present invention is prepared using 1,2-benzisothiazolin-3-one, ethyl chloroacetate, a second solvent and hydrazine hydrate as raw materials. Among them, 1,2-benzisothiazolin-3-one (isothiazolinone compound) has high algaecidal and antibacterial biological activity. The introduction of a hydrazide group into the structure by reacting with ethyl chloroacetate and hydrazine hydrate can further enhance the bactericidal activity and antibacterial performance of the second functional monomer, thereby making the polymer have more excellent antibacterial performance. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] In a first aspect, the present invention provides a composition for preparing a scale inhibitor, the composition comprising maleic anhydride, acrylic acid, a sulfonic acid anion monomer, a first functional monomer, a second functional monomer, an initiator, and water;

[0034] The raw materials for preparing the first functional monomer include 5-aminoorotic acid, a first solvent, pyridine and maleic anhydride;

[0035] The raw materials for preparing the second functional monomer include 1,2-benzisothiazolin-3-one, ethyl chloroacetate, a second solvent and hydrazine hydrate.

[0036] The acrylic acid and maleic anhydride copolymer in the composition of the present invention can dissociate into negative ions in an aqueous solution. When these negative ions collide with calcium carbonate microcrystals in the aqueous solution, they undergo physical and chemical adsorption, forming a charge-receiving layer on the surface of the calcium carbonate microcrystals. When the polymer negative ions adsorb the calcium carbonate microcrystals, they impart the same charge. The electrostatic repulsion between the charged calcium carbonate microcrystals prevents collisions between them to form large crystals, keeping them in a very small particle state, increasing the contact area between the crystals and water, and thus improving the crystal solubility. Furthermore, the electrostatic repulsion between the charged calcium carbonate microcrystals prevents collisions between them and metal heat transfer surfaces, reducing the number of crystal nuclei that can form scale layers and effectively inhibiting scale formation.

[0037] The first functional monomer of the present invention is prepared using 5-aminoorotic acid, a solvent, pyridine and maleic anhydride as raw materials. The heteroatoms in the molecular structure can be well adsorbed on the surface of carbon steel to form an anti-corrosion film, which can effectively prevent the reaction of interfacial ions, inhibit the aggregation of scale crystal nuclei on the surface of the pipeline, and improve the corrosion inhibition performance of the polymer.

[0038] The second functional monomer of the present invention is prepared using 1,2-benzisothiazolin-3-one, ethyl chloroacetate, a second solvent and hydrazine hydrate as raw materials. Among them, 1,2-benzisothiazolin-3-one (isothiazolinone compound) has high algaecidal and antibacterial biological activity. The introduction of a hydrazide group into the structure by reacting with ethyl chloroacetate and hydrazine hydrate can further enhance the bactericidal activity and antibacterial performance of the second functional monomer, thereby making the polymer have more excellent antibacterial performance.

[0039] According to some preferred embodiments, the composition comprises 100 to 120 parts by weight of maleic anhydride (for example, 100 parts, 101 parts, 102 parts, 103 parts, 104 parts, 105 parts, 106 parts, 107 parts, 108 parts, 109 parts, 110 parts, 111 parts, 112 parts, 113 parts, 114 parts, 115 parts, 116 parts, 117 parts, 118 parts, 119 parts or 120 parts), 70 to 90 parts by weight of acrylic acid (for example, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 76 parts, 77 parts, 78 parts, 79 parts, 80 parts, 81 parts, 82 parts, 83 parts, 84 parts, 86 parts, 87 parts, 88 parts, 89 parts, 90 parts, 91 parts, 92 parts, 93 parts, 94 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts or 30 parts), 20-30 parts of sulfonic acid anion monomer (for example, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts or 30 parts), 15-30 parts of the first functional monomer (for example, ... 1 part, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts or 30 parts), 15-30 parts of the second functional monomer (for example, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts or 30 parts), 0.2-0.4 parts of initiator (for example, 0.2 parts, 0.3 parts or 0.4 parts) and water 550 to 650 parts (for example, 550 parts, 555 parts, 560 parts, 565 parts, 570 parts, 575 parts, 580 parts, 585 parts, 590 parts, 595 parts, 600 parts, 605 parts, 610 parts, 615 parts, 620 parts, 625 parts, 630 parts, 635 parts, 640 parts, 645 parts or 650 parts); by controlling the amount of each component in the composition within the above range, the scale inhibitor prepared can be ensured to have excellent scale inhibition, corrosion inhibition and antibacterial properties.

[0040] According to some preferred embodiments, the molar ratio of 5-aminoorotic acid, maleic anhydride and pyridine is 1:(1.2-1.5):(1.1-1.3);

[0041] The mass ratio of 5-aminoorotic acid to the first solvent is (1-1.3):15 (for example, 1:15, 1.1:15, 1.2:15 or 1.3:15).

[0042] According to some preferred embodiments, the molar ratio of 1,2-benzisothiazolin-3-one, ethyl chloroacetate and hydrazine hydrate is 1:(1.1-1.3):(1.1-1.3);

[0043] The mass ratio of the 1,2-benzisothiazolin-3-one to the second solvent is (1-1.3):10 (for example, 1:10, 1.1:10, 1.2:10 or 1.3:10).

[0044] According to some preferred embodiments, the sulfonic acid anion monomer is at least one of allyl sulfonic acid and vinyl sulfonic acid. The selection of the sulfonic acid anion monomer in the present invention can effectively improve the stability of the polymer under high salinity conditions.

[0045] The initiator is an azo initiator, and the azo initiator is one or more of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobisisoheptanenitrile, and azobisisobutyronitrile, preferably azobisisobutylamidine hydrochloride;

[0046] The first solvent is dichloromethane;

[0047] The second solvent is ethanol; and / or

[0048] The hydrazine hydrate contains 85% hydrazine.

[0049] It should be noted that the hydrazine content of hydrazine hydrate is 85%, which means that the mass fraction of hydrazine is 85%.

[0050] In a second aspect, the present invention provides a scale inhibitor, wherein the raw materials for preparing the scale inhibitor include the composition described in the first aspect.

[0051] The scale inhibitor of the present invention includes acrylic acid and maleic anhydride that can generate a copolymer with excellent scale inhibition performance, a first functional monomer with excellent corrosion inhibition effect, and a second functional monomer with excellent bactericidal and antibacterial effect, so that the scale inhibitor has high scale inhibition efficiency, good corrosion inhibition effect, and excellent bactericidal and antibacterial performance, which can meet the requirements of cooling water treatment.

[0052] The present invention provides a third aspect of a method for preparing the scale inhibitor according to the second aspect, the method comprising the following steps:

[0053] S1. Maleic anhydride, acrylic acid, sulfonic acid anionic monomer and water are thoroughly mixed and the pH is adjusted to 5.5 to 6.5 (for example, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4 or 6.5) to obtain a blend;

[0054] S2. Add the first functional monomer and the second functional monomer to the blend, mix well, perform a first nitrogen deoxygenation, and raise the temperature to 45-50°C (for example, 45°C, 46°C, 47°C, 48°C, 49°C or 50°C) under a protective atmosphere, add an initiator to initiate a polymerization reaction, and obtain the scale inhibitor.

[0055] According to some preferred embodiments, the preparation method of the first functional monomer comprises: mixing 5-aminoorotic acid and a first solvent, performing a second nitrogen purge to remove oxygen, adding pyridine for activation treatment, then adding maleic anhydride, performing a first reaction, and recrystallizing to obtain the first functional monomer;

[0056] Preferably, the second nitrogen deoxygenation time is 30 to 40 minutes (for example, 30 minutes, 31 minutes, 32 minutes, 33 minutes, 34 minutes, 35 minutes, 36 minutes, 37 minutes, 38 minutes, 39 minutes or 40 minutes);

[0057] Preferably, the activation treatment temperature is 20-30° C. (for example, 20° C., 21° C., 22° C., 23° C., 24° C., 25° C., 26° C., 27° C., 28° C., 29° C., or 30° C.), and the activation treatment time is 2-3 h (for example, 2 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h, or 3 h);

[0058] Preferably, the first reaction is carried out under nitrogen protection, the reaction temperature is 40-50°C (for example, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C or 50°C) and the time is 2-5h (for example, 2h, 2.2h, 2.4h, 2.5h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.5h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.5h, 4.6h, 4.8h or 5h).

[0059] The reaction formula for preparing the first functional monomer of the present invention is as follows:

[0060]

[0061] In some specific embodiments of the present invention, 5-aminoorotic acid and the first solvent are mixed, and nitrogen deoxygenation is carried out for 30 to 40 minutes (for example, 30 minutes, 31 minutes, 32 minutes, 33 minutes, 34 minutes, 35 minutes, 36 minutes, 37 minutes, 38 minutes, 39 minutes or 40 minutes), and then under nitrogen protection, pyridine is added and activated at 20 to 30 degrees Celsius (for example, 20 degrees Celsius, 21 degrees Celsius, 22 degrees Celsius, 23 degrees Celsius, 24 degrees Celsius, 25 degrees Celsius, 26 degrees Celsius, 27 degrees Celsius, 28 degrees Celsius, 29 degrees Celsius or 30 degrees Celsius) for 2 to 3 hours (for example, 2 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, 2.5 hours, 2.6 hours, 2.7 hours, 2.8 hours, 2.9 hours or 3 hours), and then maleic anhydride is added and heated at 40 to 50 degrees Celsius (for example, is 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C or 50°C) for 2-5h (for example, 2h, 2.2h, 2.4h, 2.5h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.5h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.5h, 4.6h, 4. 8h or 5h), recrystallized with acetone and filtered, and then dried at 40-45°C (for example, 40°C, 41°C, 42°C, 43°C, 44°C or 45°C) for 2-4h (for example, 2h, 2.2h, 2.4h, 2.5h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.5h, 3.6h, 3.8h or 4h) to obtain the first functional monomer.

[0062] The present invention uses pyridine to activate 5-aminoorotic acid, and then reacts with maleic anhydride to introduce carbon-carbon double bonds that can undergo polyaddition. Heteroatoms are introduced into polymer molecules through a polymerization reaction. The heteroatoms can be well adsorbed on the surface of carbon steel to form an anti-corrosion film, effectively preventing the reaction of interface ions and inhibiting the aggregation of scale crystal nuclei on the surface of the pipeline, thereby improving the corrosion inhibition performance of the polymer.

[0063] According to some preferred embodiments, the preparation method of the second functional monomer includes: at room temperature, uniformly mixing 1,2-benzisothiazolin-3-one, ethyl chloroacetate and a second solvent, then adding hydrazine hydrate, conducting a second reaction until the precipitate no longer increases, and filtering to obtain the second functional monomer.

[0064] The reaction formula for preparing the second functional monomer of the present invention is as follows:

[0065]

[0066] In some specific embodiments of the present invention, 1,2-benzisothiazolin-3-one, ethyl chloroacetate and ethanol are uniformly mixed at room temperature, hydrazine hydrate with a hydrazine content of 85% is added dropwise, and the mixture is stirred until the precipitate no longer increases. The mixture is filtered, washed with ethanol and dried to obtain the second functional monomer.

[0067] The present invention adopts 1,2-benzisothiazolin-3-one (isothiazolinone compound), ethyl chloroacetate and hydrazine hydrate to react, and further introduces a hydrazide group on the basis of the isothiazolinone compound to enhance the bactericidal activity and antibacterial performance of the second functional monomer.

[0068] The third aspect of the present invention provides use of the scale inhibitor described in the second aspect in water treatment.

[0069] In industrial production, open circulating cooling water systems are currently mainly used, which are characterized by energy saving and environmental protection, and the cooling water can be recycled. After long-term circulation of cooling water, due to the evaporation and concentration of water, the pH and temperature of the medium will rise, which will inevitably cause scaling on the surface of the pipes, metal corrosion and microbial growth. The formation of scale deposits will lead to a decrease in the heat exchange efficiency of the cooling system, blockage of the pipes, and increase the initial investment and maintenance costs; corrosion will cause damage and deterioration of production equipment, and even cause serious safety accidents; microorganisms will accelerate the corrosion of equipment under the action of dissolved oxygen in water. In order to improve the cooling efficiency of water, increase the number of times water is recycled and reduce its corrosion and damage to equipment, it is necessary to treat the circulating water. The scale inhibitor provided by the present invention has high scale inhibition efficiency, good corrosion inhibition effect, and excellent antibacterial performance. It can effectively solve the problems of scaling on the surface of pipes, metal corrosion and microbial growth in cooling water, and meet the requirements of cooling water treatment.

[0070] In order to more clearly illustrate the technical solutions and advantages of the present invention, the present invention is further described below with reference to embodiments.

[0071] The test methods for the corrosion inhibition rate, scale inhibition rate, and relative antibacterial rate of the present invention refer to the following standards:

[0072] Corrosion inhibition rate (%): SY / T 5273-2000-3 Test method for static corrosion rate and corrosion inhibition rate at normal pressure.

[0073] Scale inhibition rate (%): SY / T 5673-2020-8 Determination method of scale inhibition rate.

[0074] Relative inhibition rate (%): SY / T 5890-93-6 bactericide performance evaluation method.

[0075] Example 1

[0076] Preparation of the first functional monomer:

[0077] 17 g of 5-aminoorotic acid and 250 g of dichloromethane were added to the reactor in sequence. After nitrogen deoxygenation for 30 minutes, 9.5 g of pyridine was added and activated at 30°C for 3 hours. Then, 13 g of maleic anhydride was added and reacted at 45°C for 5 hours under nitrogen protection. After recrystallization with acetone and filtration, the mixture was dried at 45°C for 4 hours to obtain the first functional monomer.

[0078] Example 2

[0079] Preparation of the second functional monomer:

[0080] 60 g of ethanol, 15 g of 1,2-benzisothiazolin-3-one, and 14 g of ethyl chloroacetate were added to the reactor in sequence and stirred evenly. Then, 7 g of 85% hydrazine hydrate was added and stirred at room temperature until the precipitation no longer increased. The mixture was filtered, washed, and dried to obtain the second functional monomer.

[0081] The first functional monomers in the following examples and comparative examples of this application were prepared by the method of Example 1, and the second functional monomers were all prepared by the method of Example 2.

[0082] Example 3

[0083] S1 was added to the reactor 110g of maleic anhydride, 80g of acrylic acid, 25g of allyl sulfonic acid, deionized water mixed, the mixture was adjusted to pH 6.5 with granular base, stirred and mixed to obtain a blend;

[0084] S2. Add 20 g of the first functional monomer and 20 g of the second functional monomer to the blend, stir and mix evenly, blow nitrogen to deoxygenate for 30 minutes, raise the temperature to 50 ° C under nitrogen protection, add 0.3 g of azobisisobutylamidine hydrochloride to initiate polymerization for 4 hours to obtain a scale inhibitor.

[0085] Example 4

[0086] S1 was added to the reactor 100g of maleic anhydride, 90g of acrylic acid, 30g of allyl sulfonic acid, deionized water, mixed, the mixture was adjusted to pH 5.5 with granular base, stirred and mixed to obtain a blend;

[0087] S2. Add 25 g of the first functional monomer and 20 g of the second functional monomer to the blend, stir and mix evenly, blow nitrogen to deoxygenate for 30 minutes, raise the temperature to 50 ° C under nitrogen protection, add 0.3 g of azobisisobutylamidine hydrochloride to initiate polymerization for 4 hours to obtain a scale inhibitor.

[0088] Example 5

[0089] S1 was added to the reactor 120g of maleic anhydride, 75g of acrylic acid, 30g of allyl sulfonic acid, deionized water mixed, the mixture was adjusted to pH 6 with granular base, stirred and mixed to obtain a blend;

[0090] S2. Add 20 g of the first functional monomer and 25 g of the second functional monomer to the blend, stir and mix evenly, blow nitrogen to deoxygenate for 30 minutes, raise the temperature to 50 ° C under nitrogen protection, add 0.3 g of azobisisobutylamidine hydrochloride to initiate polymerization for 4 hours to obtain a scale inhibitor.

[0091] Comparative Example 1

[0092] Comparative Example 1 is substantially the same as Example 3, with the only difference being that the first functional monomer is not added.

[0093] Comparative Example 2

[0094] Comparative Example 1 is substantially the same as Example 3, with the only difference being that the mass of the first functional monomer is 50 g.

[0095] Comparative Example 3

[0096] Comparative Example 3 is substantially the same as Example 3, except that no second functional monomer is added.

[0097] Comparative Example 4

[0098] Comparative Example 4 is substantially the same as Example 3, with the only difference being that the mass of the second functional monomer is 50 g.

[0099] Comparative Example 5

[0100] Comparative Example 5 is substantially the same as Example 3, except that the first functional monomer and the second functional monomer are not added.

[0101] Comparative Example 6

[0102] Comparative Example 6 is substantially the same as Example 3, except that the first functional monomer is replaced by 5-aminoorotic acid.

[0103] Comparative Example 7

[0104] Comparative Example 7 is substantially the same as Example 3, with the only difference being that the second functional monomer is replaced by 1,2-benzisothiazolin-3-one.

[0105] Table 1. Performance data of the scale inhibitors prepared in Examples and Comparative Examples

[0106]

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a scale inhibitor, characterized in that: The preparation method comprises the following steps: S1. Maleic anhydride, acrylic acid, sulfonic acid anionic monomer and water are thoroughly mixed and the pH is adjusted to 5.5~6.5 to obtain a blend; S2. The first functional monomer and the second functional monomer are added to the blend, mixed, and then subjected to a first nitrogen deoxygenation process, and heated to 45 to 50 ° C under a protective atmosphere, and an initiator is added to initiate the polymerization reaction to obtain the scale inhibitor; The preparation method of the first functional monomer comprises: mixing 5-aminoorotic acid and a first solvent, performing a second nitrogen-purging process to remove oxygen, adding pyridine for activation treatment, then adding maleic anhydride, performing a first reaction, and recrystallizing to obtain the first functional monomer; the activation treatment temperature is 20-30° C., and the time is 2-3 hours; The preparation method of the second functional monomer includes: uniformly mixing 1,2-benzisothiazolin-3-one, ethyl chloroacetate and a second solvent at room temperature, then adding hydrazine hydrate, performing a second reaction until precipitation no longer increases, and filtering to obtain the second functional monomer.

2. The preparation method according to claim 1, wherein the time for the second nitrogen deoxygenation is 30 to 40 minutes.

3. The preparation method according to claim 1, wherein the first reaction is carried out under nitrogen protection, the reaction temperature is 40-50°C, and the reaction time is 2-5 hours.

4. The preparation method according to claim 1, characterized in that In parts by weight, the following ingredients include 100-120 parts of maleic anhydride, 70-90 parts of acrylic acid, 20-30 parts of sulfonic acid anion monomer, 15-30 parts of first functional monomer, 15-30 parts of second functional monomer, 0.2-0.4 parts of initiator and 550-650 parts of water.

5. The preparation method according to claim 1, characterized in that The molar ratio of 5-aminoorotic acid, maleic anhydride and pyridine is 1:(1.2-1.5):(1.1-1.3); The mass ratio of 5-aminoorotic acid to the first solvent is (1-1.3):

15.

6. The preparation method according to claim 1, characterized in that The molar ratio of 1,2-benzisothiazolin-3-one, ethyl chloroacetate and hydrazine hydrate is 1:(1.1-1.3):(1.1-1.3); The mass ratio of 1,2-benzisothiazolin-3-one to the second solvent is (1-1.3):

10.

7. The preparation method according to claim 1, characterized in that The sulfonic acid anion monomer is at least one of allyl sulfonic acid and vinyl sulfonic acid; The initiator is an azo initiator, and the azo initiator is one or more of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobisisoheptanonitrile, and azobisisobutyronitrile; The first solvent is dichloromethane; The second solvent is ethanol; The hydrazine hydrate has a hydrazine content of 85%.

8. The preparation method according to claim 7, characterized in that The azo initiator is azobisisobutylamidine hydrochloride.

9. A scale inhibitor, characterized in that: The method according to any one of claims 1 to 8 is used to prepare the compound.

10. Use of the scale inhibitor according to claim 9 in water treatment.

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