An anionic scale inhibitor and its preparation method

Abstract

The invention discloses an anionic scale inhibitor and a preparation method thereof, and relates to the technical field of scale inhibitors. When preparing the anionic scale inhibitor, the present invention reacts diethylenetriamine with methyl acrylate to obtain a scale inhibitor precursor; reacts the scale inhibitor precursor with ethylenediamine to obtain a one-step hyperbranched scale inhibitor; reacts the one-step hyperbranched scale inhibitor with maleic anhydride to obtain a two-step hyperbranched scale inhibitor; reacts 2-quinolinecarboxylic acid with 6-mercapto-1-hexanol to obtain 2-quinolinecarboxylic acid-6-mercaptohexyl ester; and reacts the two-step hyperbranched scale inhibitor with 2-quinolinecarboxylic acid-6-mercaptohexyl ester to obtain anionic scale inhibitor. The anionic scale inhibitor prepared by the present invention has excellent corrosion inhibition and scale inhibition performance.

Description

Technical Field

[0001] The invention relates to the technical field of scale inhibitors, in particular to an anionic scale inhibitor and a preparation method thereof. Background Art

[0002] Scaling is a common problem in industrial systems, water circulation systems and other industrial pipelines, which leads to problems such as reduced production efficiency and energy loss. In industrial circulating water, most of it is surface water, and its recycling brings serious corrosion and scaling problems to the heat exchange system. During the circulation process, with the changes in water temperature and pH, the concentration of metal ions such as calcium and magnesium continues to increase. Therefore, the circulation pipeline is prone to scaling. After the scale is deposited on the surface of the heat exchanger, the heat exchange efficiency of the equipment will be reduced, and energy loss will increase, wasting resources; then the equipment will be corroded and damage will be accelerated; secondly, the cross-sectional area of ​​the fluid flow will be reduced, resulting in an increase in the heat exchange area of ​​the equipment and an increase in investment costs; when the scaling is serious, it will cause pipeline blockage and even cause production stoppage accidents. Therefore, the scale prevention problem is an important issue that needs to be solved urgently. Summary of the invention

[0003] The purpose of the present invention is to provide an anionic scale inhibitor and a preparation method thereof to solve the problems existing in the prior art.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] The invention discloses an anionic scale inhibitor, wherein the anionic scale inhibitor is prepared by reacting a scale inhibitor precursor with ethylenediamine to obtain a one-step hyperbranched scale inhibitor; reacting the one-step hyperbranched scale inhibitor with maleic anhydride to obtain a two-step hyperbranched scale inhibitor; and reacting the two-step hyperbranched scale inhibitor with 2-quinolinecarboxylic acid-6-mercaptohexyl ester to obtain the anionic scale inhibitor.

[0006] As an optimization, the scale inhibitor precursor is prepared by reacting diethylenetriamine with methyl acrylate.

[0007] As an optimization, the 2-quinolinecarboxylic acid-6-mercaptohexyl ester is prepared by reacting 2-quinolinecarboxylic acid with 6-mercapto-1-hexanol.

[0008] A method for preparing an anionic scale inhibitor comprises the following steps:

[0009] (1) Diethylenetriamine and methanol were mixed in a mass ratio of 1: (8-10), and methyl acrylate with a molar amount of 5.0-5.2 times that of diethylenetriamine was added dropwise at a uniform rate within 30 minutes at 0-2°C and 300-500 r / min under a nitrogen atmosphere. The temperature was raised to 34-36°C, and the reaction was continued with stirring for 22-24 hours. The scale inhibitor precursor was dried at 3-5 Pa and 50-60°C for 6-8 hours to obtain the scale inhibitor precursor. The scale inhibitor precursor and methanol were mixed in a mass ratio of 1: (10-12), and methyl acrylate with a molar amount of 5.0-5.2 times that of diethylenetriamine was added dropwise at a uniform rate within 30 minutes at 0-2°C and 300-500 r / min under a nitrogen atmosphere. The molar amount of ethylenediamine, which is 5.0-5.2 times of the scale inhibitor precursor, is heated to 24-26°C, and the reaction is continued with stirring for 22-24 hours, and dried at 3-5Pa and 50-60°C for 6-8 hours to obtain a one-step hyperbranched scale inhibitor; maleic anhydride and deionized water are mixed uniformly at a mass ratio of 1:(16-18), and a one-step hyperbranched scale inhibitor, which is 0.08-0.1 times of the molar amount of maleic anhydride, is uniformly added dropwise within 1 hour at 10-30°C and 300-500r / min stirring conditions, and the temperature is raised to 59-61°C, and the reaction is continued with stirring for 11-13 hours, and the two-step hyperbranched scale inhibitor is dried at 3-5Pa and 50-60°C for 6-8 hours.

[0010] (2) Add the two-step hyperbranched scale inhibitor and 2-quinolinecarboxylic acid-6-mercaptohexyl ester in a molar ratio of 1:(10.0-10.2) to N,N-dimethylformamide (20-24 times the mass of the two-step hyperbranched scale inhibitor), then add azobisisobutyronitrile (0.04-0.06 times the mass of the two-step hyperbranched scale inhibitor) and mix well. Stir and react at 60-70°C and 300-500 r / min for 3-4 hours, cool to room temperature, adjust the pH to neutral with aqueous sodium hydroxide solution, and dry at 3-5 Pa and 50-60°C for 6-8 hours to obtain an anionic scale inhibitor.

[0011] As an optimization, the reaction process of the scale inhibitor precursor in step (1) is:

[0012] .

[0013] As an optimization, the reaction process of the one-step hyperbranched scale inhibitor in step (1) is:

[0014] .

[0015] As an optimization, the reaction process of the two-step hyperbranched scale inhibitor in step (1) is:

[0016] .

[0017] As an optimization, the preparation process of 2-quinolinecarboxylic acid-6-mercaptohexyl ester in step (2) is as follows: 2-quinolinecarboxylic acid, 6-mercapto-1-hexanol, and N,N'-dicyclohexylcarbodiimide are added in a molar ratio of 1:1:1 to dichloromethane with a mass of 20 to 24 times that of 2-quinolinecarboxylic acid, and then 4-dimethylaminopyridine with a mass of 0.02 to 0.04 times that of 2-quinolinecarboxylic acid is added, and the mixture is stirred at 10 to 30°C and 300 to 500 r / min for 3 to 4 hours, and dried at 3 to 5 Pa and 50 to 60°C for 6 to 8 hours to obtain 2-quinolinecarboxylic acid-6-mercaptohexyl ester;

[0018] The reaction process is:

[0019] .

[0020] As an optimization, the mass fraction of the sodium hydroxide aqueous solution in step (2) is 20-24%.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0022] When preparing anionic scale inhibitor, the present invention comprises the following steps: reacting diethylenetriamine with methyl acrylate to obtain a scale inhibitor precursor; reacting the scale inhibitor precursor with ethylenediamine to obtain a one-step hyperbranched scale inhibitor; reacting the one-step hyperbranched scale inhibitor with maleic anhydride to obtain a two-step hyperbranched scale inhibitor; reacting 2-quinolinecarboxylic acid with 6-mercapto-1-hexanol to obtain 2-quinolinecarboxylic acid-6-mercaptohexyl ester; and reacting the two-step hyperbranched scale inhibitor with 2-quinolinecarboxylic acid-6-mercaptohexyl ester to obtain anionic scale inhibitor.

[0023] Firstly, the Michael reaction is adopted to react diethylenetriamine with methyl acrylate to obtain a scale inhibitor precursor, and the scale inhibitor precursor is reacted with ethylenediamine to obtain a one-step hyperbranched scale inhibitor, and amide groups and amino groups are introduced into the one-step hyperbranched scale inhibitor. The amide group is stable in nature and can chelate metal cations in the solution, giving the anionic scale inhibitor excellent scale inhibition performance; the one-step hyperbranched scale inhibitor is reacted with maleic anhydride to obtain a two-step hyperbranched scale inhibitor, and the amino group on the one-step hyperbranched scale inhibitor undergoes an amidation reaction with maleic anhydride, and a carbon-carbon double bond and a carboxylic acid group are introduced into the two-step hyperbranched scale inhibitor. The carboxylic acid group also has the property of chelating metal cations in the solution, giving the anionic scale inhibitor excellent scale inhibition performance.

[0024] Secondly, 2-quinolinecarboxylic acid is reacted with 6-mercapto-1-hexanol to prepare 2-quinolinecarboxylic acid-6-mercaptohexyl ester, a thiol group is introduced into 2-quinolinecarboxylic acid-6-mercaptohexyl ester, and the carbon-carbon double bond on the two-step hyperbranched scale inhibitor reacts with the thiol group on 2-quinolinecarboxylic acid-6-mercaptohexyl ester to prepare an anionic scale inhibitor, and a quinoline derivative is introduced into the anionic scale inhibitor. The quinoline derivative contains a quinoline ring, a N atom and an O atom with high electronegativity, so that the adsorption capacity of the anionic scale inhibitor on the metal is enhanced, and the anionic scale inhibitor can be adsorbed on the metal surface to form a dense protective layer. The quinoline derivative can also reduce the anionic Cl - , S 2- The enrichment in the occluded area slows down the acidification rate, thus giving the anionic scale inhibitor excellent corrosion inhibition performance. DETAILED DESCRIPTION

[0025] 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 making creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] A method for preparing an anionic scale inhibitor, comprising the following steps:

[0028] (1) Diethylenetriamine and methanol were mixed at a mass ratio of 1:8, and methyl acrylate (5.0 times the molar amount of diethylenetriamine) was uniformly added dropwise at a rate of 1:8 under nitrogen atmosphere at 0°C and 300 r / min stirring conditions within 30 minutes, the temperature was raised to 34°C, the stirring reaction was continued for 24 hours, and the scale inhibitor precursor was prepared at 3Pa and 50°C for 8 hours; the scale inhibitor precursor and methanol were mixed at a mass ratio of 1:10, and the scale inhibitor precursor was uniformly added dropwise at a rate of 1:10 under nitrogen atmosphere at 0°C and 300 r / min stirring conditions within 30 minutes. Add 5.0 times the molar amount of ethylenediamine as the scale inhibitor precursor at a rapid speed, raise the temperature to 24°C, continue stirring and reacting for 24 hours, and dry at 3Pa, 50°C for 8 hours to obtain a one-step hyperbranched scale inhibitor; mix maleic anhydride and deionized water at a mass ratio of 1:16, and under the stirring conditions of 10°C and 300r / min, uniformly add 0.08 times the molar amount of maleic anhydride as the one-step hyperbranched scale inhibitor within 1 hour, raise the temperature to 59°C, continue stirring and reacting for 13 hours, and dry at 3Pa, 50°C for 8 hours to obtain a two-step hyperbranched scale inhibitor;

[0029] (2) 2-quinolinecarboxylic acid, 6-mercapto-1-hexanol and N,N'-dicyclohexylcarbodiimide were added to dichloromethane (20 times the mass of 2-quinolinecarboxylic acid) in a molar ratio of 1:1:1, and then 4-dimethylaminopyridine (0.02 times the mass of 2-quinolinecarboxylic acid) was added, and the mixture was stirred at 10°C and 300 r / min for 4 h, and dried at 3 Pa and 50°C for 8 h to obtain 2-quinolinecarboxylic acid-6-mercaptohexyl ester; the two-step hyperbranched scale inhibitor, 2-quinolinecarboxylic acid 6-Mercaptohexyl methacrylate was added to N,N-dimethylformamide (20 times the mass of the second-step hyperbranched scale inhibitor) at a molar ratio of 1:10, and then 0.04 times the mass of azobisisobutyronitrile (20 times the mass of the second-step hyperbranched scale inhibitor) was added and mixed evenly. The mixture was stirred at 60°C and 300 r / min for 4 hours, cooled to room temperature, and the pH was adjusted to neutral with a 20% sodium hydroxide aqueous solution. The mixture was dried at 3 Pa and 50°C for 8 hours to obtain an anionic scale inhibitor.

[0030] Example 2

[0031] A method for preparing an anionic scale inhibitor, comprising the following steps:

[0032] (1) Diethylenetriamine and methanol were mixed at a mass ratio of 1:9, and methyl acrylate (5.1 times the molar amount of diethylenetriamine) was uniformly added dropwise at a rate of 1:9 under a nitrogen atmosphere at 1°C and 400 r / min stirring conditions within 30 min, the temperature was raised to 35°C, the stirring reaction was continued for 23 h, and the scale inhibitor precursor was prepared at 4 Pa ​​and 55°C for 7 h; the scale inhibitor precursor and methanol were mixed at a mass ratio of 1:11, and the scale inhibitor precursor was uniformly added dropwise at a rate of 1:11 under a nitrogen atmosphere at 1°C and 400 r / min stirring conditions within 30 min. Add 5.1 times the molar amount of ethylenediamine as the scale inhibitor precursor at a rapid speed, raise the temperature to 25°C, continue stirring and reacting for 23 hours, and dry at 4Pa, 55°C for 7 hours to obtain a one-step hyperbranched scale inhibitor; mix maleic anhydride and deionized water at a mass ratio of 1:17, and add 0.09 times the molar amount of maleic anhydride as the one-step hyperbranched scale inhibitor at a uniform speed within 1 hour at 20°C, 400r / min stirring conditions, raise the temperature to 60°C, continue stirring and reacting for 12 hours, and dry at 4Pa, 55°C for 7 hours to obtain a two-step hyperbranched scale inhibitor;

[0033] (2) 2-Quinolinecarboxylic acid, 6-mercapto-1-hexanol, and N,N'-dicyclohexylcarbodiimide were added in a molar ratio of 1:1:1 to dichloromethane (22 times the mass of 2-quinolinecarboxylic acid), and then 4-dimethylaminopyridine (0.03 times the mass of 2-quinolinecarboxylic acid) was added. The mixture was stirred at 20°C and 400 r / min for 3.5 h, and dried at 4 Pa ​​and 55°C for 7 h to obtain 2-quinolinecarboxylic acid-6-mercaptohexyl ester. The two-step hyperbranched scale inhibitor, 2-quinoline Carboxylic acid-6-mercaptohexyl ester was added to N,N-dimethylformamide (22 times the mass of the two-step hyperbranched scale inhibitor) at a molar ratio of 1:10.1, and then azobisisobutyronitrile (0.05 times the mass of the two-step hyperbranched scale inhibitor) was added and mixed evenly. The mixture was stirred at 65°C and 400r / min for 3.5h, cooled to room temperature, and the pH was adjusted to neutral with a 22% mass fraction of sodium hydroxide aqueous solution. The mixture was dried at 4Pa and 55°C for 7h to obtain an anionic scale inhibitor.

[0034] Example 3

[0035] (1) Diethylenetriamine and methanol were mixed in a mass ratio of 1:10, and methyl acrylate (5.2 times the molar amount of diethylenetriamine) was uniformly added dropwise within 30 minutes at 2°C and 500 r / min under a nitrogen atmosphere, and the temperature was raised to 36°C, and the reaction was continued with stirring for 22 hours. The scale inhibitor precursor was prepared by drying at 5 Pa and 60°C for 6 hours. The scale inhibitor precursor and methanol were mixed in a mass ratio of 1:12, and the scale inhibitor precursor was uniformly mixed with methanol in a mass ratio of 1:12, and the scale inhibitor precursor was prepared by drying at 2°C and 500 r / min under a nitrogen atmosphere for 30 minutes. Uniformly drip 5.2 times the molar amount of the scale inhibitor precursor ethylenediamine, heat to 26°C, continue stirring to react for 22 hours, dry at 5Pa, 60°C for 6 hours to obtain a one-step hyperbranched scale inhibitor; uniformly mix maleic anhydride and deionized water at a mass ratio of 1:18, uniformly drip 0.1 times the molar amount of maleic anhydride in one-step hyperbranched scale inhibitor at 30°C, 500r / min stirring conditions within 1 hour, heat to 61°C, continue stirring to react for 11 hours, dry at 5Pa, 60°C for 6 hours to obtain a two-step hyperbranched scale inhibitor;

[0036] (2) 2-Quinolinecarboxylic acid, 6-mercapto-1-hexanol, and N,N'-dicyclohexylcarbodiimide were added to dichloromethane (24 times the mass of 2-quinolinecarboxylic acid) in a molar ratio of 1:1:1, and then 4-dimethylaminopyridine (0.04 times the mass of 2-quinolinecarboxylic acid) was added, and the mixture was stirred at 30°C and 500 r / min for 3 h, and dried at 5 Pa and 60°C for 6 h to obtain 2-quinolinecarboxylic acid-6-mercaptohexyl ester; the two-step hyperbranched scale inhibitor, 2-quinoline Carboxylic acid-6-mercaptohexyl ester was added to N,N-dimethylformamide (24 times the mass of the two-step hyperbranched scale inhibitor) at a molar ratio of 1:10.2, and then azobisisobutyronitrile (0.06 times the mass of the two-step hyperbranched scale inhibitor) was added and mixed evenly. The mixture was stirred at 70°C and 500 r / min for 3 hours, cooled to room temperature, and the pH was adjusted to neutral with a 24% mass fraction of sodium hydroxide aqueous solution. The mixture was dried at 5 Pa and 60°C for 6 hours to obtain an anionic scale inhibitor.

[0037] Comparative Example 1

[0038] The difference between the preparation method of the anionic scale inhibitor of Comparative Example 1 and Example 2 lies in the difference in step (1), and step (1) is modified as follows: diethylenetriamine and methanol are uniformly mixed in a mass ratio of 1:9, and 5.1 times the molar amount of allylamine is uniformly added dropwise within 30 minutes under a nitrogen atmosphere at 1°C and 400 r / min stirring conditions, the temperature is raised to 35°C, the stirring reaction is continued for 23 hours, and the mixture is dried at 4Pa and 55°C for 7 hours to obtain a one-step hyperbranched scale inhibitor; maleic anhydride and deionized water are uniformly mixed in a mass ratio of 1:17, and 0.09 times the molar amount of maleic anhydride is uniformly added dropwise within 1 hour under 20°C and 400 r / min stirring conditions, the temperature is raised to 60°C, the stirring reaction is continued for 12 hours, and the mixture is dried at 4Pa and 55°C for 7 hours to obtain a two-step hyperbranched scale inhibitor. The remaining steps are the same as in Example 2.

[0039] Comparative Example 2

[0040] The difference between the preparation method of the anionic scale inhibitor of Comparative Example 2 and Example 2 lies in the difference in step (1), and step (1) is modified as follows: diethylenetriamine and methanol are uniformly mixed in a mass ratio of 1:9, and methyl acrylate with a molar amount of 5.1 times that of diethylenetriamine is uniformly added dropwise within 30 minutes under a nitrogen atmosphere at 1°C and 400 r / min stirring conditions, the temperature is raised to 35°C, the stirring reaction is continued for 23 hours, and the mixture is dried at 4Pa and 55°C for 7 hours to obtain a one-step hyperbranched scale inhibitor; the one-step hyperbranched scale inhibitor and methanol are uniformly mixed in a mass ratio of 1:11, and allylamine with a molar amount of 5.1 times that of the one-step hyperbranched scale inhibitor is uniformly added dropwise within 30 minutes under a nitrogen atmosphere at 1°C and 400 r / min stirring conditions, the temperature is raised to 25°C, the stirring reaction is continued for 23 hours, and the mixture is dried at 4Pa and 55°C for 7 hours to obtain a two-step hyperbranched scale inhibitor. The remaining steps are the same as those of Example 2.

[0041] Comparative Example 3

[0042] The preparation method of the anionic scale inhibitor of Comparative Example 3 is different from that of Example 2 in that step (2) is not performed, and step (1) is modified as follows: diethylenetriamine and methanol are uniformly mixed in a mass ratio of 1:10, and methyl acrylate with a molar amount of 5.2 times that of diethylenetriamine is added dropwise at a uniform rate within 30 minutes under a nitrogen atmosphere at 2°C and 500 r / min stirring conditions, the temperature is raised to 36°C, the stirring reaction is continued for 22 hours, and the scale inhibitor precursor is prepared at 5 Pa and 60°C for 6 hours; the scale inhibitor precursor and methanol are uniformly mixed in a mass ratio of 1:12, and the scale inhibitor precursor is uniformly mixed in a nitrogen atmosphere at 2°C and 500 r / min stirring conditions, Add 5.2 times the molar amount of ethylenediamine as the scale inhibitor precursor at a uniform speed within 30 minutes, heat to 26°C, continue stirring and reacting for 22 hours, and dry at 5Pa, 60°C for 6 hours to obtain a one-step hyperbranched scale inhibitor; mix maleic anhydride and deionized water at a mass ratio of 1:18, add 0.1 times the molar amount of maleic anhydride as the one-step hyperbranched scale inhibitor at a uniform speed within 1 hour at 30°C, 500r / min stirring conditions, heat to 61°C, continue stirring and reacting for 11 hours, cool to room temperature, adjust the pH to neutral with a 22% mass fraction of sodium hydroxide aqueous solution, and dry at 4Pa, 55°C for 7 hours to obtain an anionic scale inhibitor. The remaining steps are the same as in Example 2.

[0043] Test Example 1

[0044] Test of scale inhibition performance

[0045] Test method: GB / T16632 "Calcium carbonate precipitation method" for the determination of scale inhibition performance of water treatment agents was used to determine the scale inhibition rates of the examples and comparative examples. The results are shown in Table 1.

[0046] Table 1

[0047] ;

[0048] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 1, it can be found that the anionic scale inhibitor prepared in the present invention has good scale inhibition performance.

[0049] By comparison, the scale inhibition rates of Examples 1 to 3 are greater than that of Comparative Example 1, indicating that a scale inhibitor precursor is prepared by reacting diethylenetriamine with methyl acrylate using the Michael reaction, and the scale inhibitor precursor is reacted with ethylenediamine to prepare a one-step hyperbranched scale inhibitor, and amide groups and amino groups are introduced into the one-step hyperbranched scale inhibitor. The amide groups are stable in nature and can chelate metal cations in the solution, giving the anionic scale inhibitor excellent scale inhibition performance.

[0050] By comparison, the scale inhibition rates of Examples 1 to 3 are greater than that of Comparative Example 2, indicating that the one-step hyperbranched scale inhibitor is reacted with maleic anhydride to obtain a two-step hyperbranched scale inhibitor, the amino group on the one-step hyperbranched scale inhibitor undergoes an amidation reaction with maleic anhydride, and a carbon-carbon double bond and a carboxylic acid group are introduced into the two-step hyperbranched scale inhibitor, and the carboxylic acid group also has the property of chelating metal cations in the solution, giving the anionic scale inhibitor excellent scale inhibition performance.

[0051] Test Example 2

[0052] Corrosion inhibition performance test

[0053] Test method: The corrosion inhibition rates of the examples and comparative examples were measured using the "rotating coupon corrosion test method" of GB / T18175 national standard for the determination of corrosion inhibition performance of water treatment agents. The results are shown in Table 2.

[0054] Table 2

[0055] ;

[0056] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 2, it can be found that the anionic scale inhibitor prepared by the present invention has good corrosion inhibition performance.

[0057] By comparison, the corrosion inhibition rates of Examples 1 to 3 are greater than that of Comparative Example 3, indicating that 2-quinolinecarboxylic acid is reacted with 6-mercapto-1-hexanol to prepare 2-quinolinecarboxylic acid-6-mercaptohexyl ester, a thiol group is introduced into 2-quinolinecarboxylic acid-6-mercaptohexyl ester, the carbon-carbon double bond on the two-step hyperbranched scale inhibitor reacts with the thiol group on 2-quinolinecarboxylic acid-6-mercaptohexyl ester to prepare an anionic scale inhibitor, and a quinoline derivative is introduced into the anionic scale inhibitor. The quinoline derivative contains a quinoline ring, a N atom and an O atom with high electronegativity, so that the adsorption capacity of the anionic scale inhibitor on the metal is enhanced, and the anionic scale inhibitor can be adsorbed on the metal surface to form a dense protective layer. The quinoline derivative can also reduce the anionic Cl - , S 2-The enrichment in the occluded area slows down the acidification rate, thus giving the anionic scale inhibitor excellent corrosion inhibition performance.

[0058] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An anionic scale inhibitor, characterized in that: The anionic scale inhibitor is prepared by reacting a scale inhibitor precursor with ethylenediamine to obtain a one-step hyperbranched scale inhibitor; reacting the one-step hyperbranched scale inhibitor with maleic anhydride to obtain a two-step hyperbranched scale inhibitor; and reacting the two-step hyperbranched scale inhibitor with 2-quinolinecarboxylic acid-6-mercaptohexyl ester to obtain the antiscalant. The scale inhibitor precursor is prepared by reacting diethylenetriamine with methyl acrylate.

2. An anionic scale inhibitor according to claim 1, characterized in that: The 2-quinolinecarboxylic acid-6-mercaptohexyl ester is prepared by reacting 2-quinolinecarboxylic acid with 6-mercapto-1-hexanol.

3. A method for preparing anionic scale inhibitor, characterized in that: The method comprises the following preparation steps: (1) Diethylenetriamine and methanol were mixed in a mass ratio of 1: (8-10), and methyl acrylate with a molar amount of 5.0-5.2 times that of diethylenetriamine was added dropwise at a uniform rate within 30 minutes at 0-2°C and 300-500 r / min under a nitrogen atmosphere. The temperature was raised to 34-36°C, and the reaction was continued with stirring for 22-24 hours. The scale inhibitor precursor was dried at 3-5 Pa and 50-60°C for 6-8 hours to obtain the scale inhibitor precursor. The scale inhibitor precursor and methanol were mixed in a mass ratio of 1: (10-12), and methyl acrylate with a molar amount of 5.0-5.2 times that of diethylenetriamine was added dropwise at a uniform rate within 30 minutes at 0-2°C and 300-500 r / min under a nitrogen atmosphere. The molar amount of ethylenediamine, which is 5.0-5.2 times of the scale inhibitor precursor, is heated to 24-26°C, and the reaction is continued with stirring for 22-24 hours, and dried at 3-5Pa and 50-60°C for 6-8 hours to obtain a one-step hyperbranched scale inhibitor; maleic anhydride and deionized water are mixed uniformly at a mass ratio of 1:(16-18), and a one-step hyperbranched scale inhibitor, which is 0.08-0.1 times of the molar amount of maleic anhydride, is uniformly added dropwise within 1 hour at 10-30°C and 300-500r / min stirring conditions, and the temperature is raised to 59-61°C, and the reaction is continued with stirring for 11-13 hours, and the two-step hyperbranched scale inhibitor is dried at 3-5Pa and 50-60°C for 6-8 hours. (2) Add the two-step hyperbranched scale inhibitor and 2-quinolinecarboxylic acid-6-mercaptohexyl ester in a molar ratio of 1:(10.0-10.2) to N,N-dimethylformamide (20-24 times the mass of the two-step hyperbranched scale inhibitor), then add azobisisobutyronitrile (0.04-0.06 times the mass of the two-step hyperbranched scale inhibitor) and mix well. Stir and react at 60-70°C and 300-500 r / min for 3-4 hours, cool to room temperature, adjust the pH to neutral with aqueous sodium hydroxide solution, and dry at 3-5 Pa and 50-60°C for 6-8 hours to obtain an anionic scale inhibitor.

4. The method for preparing an anionic scale inhibitor according to claim 3, characterized in that: The reaction process of the scale inhibitor precursor in step (1) is: 。 5. The method for preparing an anionic scale inhibitor according to claim 3, characterized in that: The reaction process of the one-step hyperbranched scale inhibitor in step (1) is: 。 6. The method for preparing an anionic scale inhibitor according to claim 3, characterized in that: The reaction process of the two-step hyperbranched scale inhibitor in step (1) is: 。 7. The method for preparing an anionic scale inhibitor according to claim 3, characterized in that: The preparation process of 2-quinolinecarboxylic acid-6-mercaptohexyl ester in step (2) is as follows: 2-quinolinecarboxylic acid, 6-mercapto-1-hexanol, and N,N'-dicyclohexylcarbodiimide are added in a molar ratio of 1:1:1 to dichloromethane with a mass of 20 to 24 times that of 2-quinolinecarboxylic acid, and then 4-dimethylaminopyridine with a mass of 0.02 to 0.04 times that of 2-quinolinecarboxylic acid is added, and the mixture is stirred at 10 to 30° C. and 300 to 500 r / min for 3 to 4 hours, and dried at 3 to 5 Pa and 50 to 60° C. for 6 to 8 hours to obtain 2-quinolinecarboxylic acid-6-mercaptohexyl ester; The reaction process is: 。 8. The method for preparing an anionic scale inhibitor according to claim 3, characterized in that: The mass fraction of the sodium hydroxide aqueous solution in step (2) is 20-24%.

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