Hydroxybenzoyl hydrazine modification-based polyaspartic acid derivative as well as preparation method and application thereof

Abstract

The invention discloses a polyaspartic acid derivative based on hydroxybenzoyl hydrazine modification and a preparation method and application thereof.The hydroxybenzoyl hydrazine is introduced into a peptide chain of polyaspartic acid through a graft copolymerization method, three derivatives are synthesized, the derivatives can be combined with metal ions such as Ca < 2 + > to generate water-soluble complexes, and the water-soluble complexes can be used for preparing the polyaspartic acid derivative based on hydroxybenzoyl hydrazine modification and the preparation method and application of the polyaspartic acid derivative based on hydroxybenzoyl hydrazine modification. The scale inhibitor has good scale inhibition and antibacterial properties, and also has a certain corrosion inhibition effect. In addition, the derivative has a good inhibition effect on escherichia coli, and the escherichia coli is a main pollution source in circulating cooling water. The derivative also has better optical properties, and is convenient to cooperate with a fluorescence monitor in industrial production to monitor the concentration of the derivative in a circulating cooling water pipeline in real time, so that the industrial production process is optimized. Therefore, the scale inhibition performance, the corrosion inhibition performance and the antibacterial performance of the polyaspartic acid derivative are remarkably improved by modifying the polyaspartic acid derivative through the hydroxybenzoyl hydrazine, meanwhile, application of phosphorus-containing compounds is avoided, and the negative influence on the environment is effectively relieved.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial circulating water treatment, and specifically relates to a polyaspartic acid derivative modified based on hydroxybenzoylhydrazide, a preparation method and application thereof. Background Art

[0002] Cooling water circulation system is widely used in industrial production, but due to the presence of calcium ions, sulfate ions, carbonate ions and other anions and cations in the circulation system, the cooling water will have problems such as scale deposition and pipeline corrosion during the circulation process. Ion exchange membranes, ion exchange resins, and adding water treatment agents are commonly used in industry to solve this problem, but since the ion exchange membrane method and ion exchange method require regular replacement of ion exchange membranes and ion exchange resins, the cost is relatively high, so the most popular and convenient method is to add water treatment agents.

[0003] Polyaspartic acid has attracted extensive attention in the field of industrial circulating water due to its non-toxic, pollution-free and biodegradable properties. Current research focuses on improving its scale inhibition, sustained release and antibacterial properties by modifying its structure. Hydroxybenzoic acid has the ability to complex with metal ions and has a certain bactericidal ability. The hydroxyl group on its benzene ring is easily oxidized, which also suggests that it may have good corrosion inhibition as a circulating cooling water treatment agent. At the same time, hydroxybenzoic acid has excellent optical properties, which makes it possible to achieve real-time monitoring as a water treatment agent. Literature reports that the lone pair of electrons on the amide bond can adsorb microcrystals with a tendency to scale in the solution, causing these microcrystals to aggregate and carry negative charges. The mutual repulsion of charges of the same kind can effectively hinder the formation of large crystals, thereby playing an important role in the scale inhibition process. Based on this mechanism, the present invention innovatively introduces the hydroxybenzoyl hydrazide structural fragment into the peptide chain of polyaspartic acid through an amide bond, aiming to prepare a multifunctional water treatment agent that integrates scale inhibition, corrosion inhibition, antibacterial and fluorescence properties. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a polyaspartic acid derivative modified with hydroxybenzoylhydrazide, a preparation method and application thereof. The polyaspartic acid derivative provided by the present invention has effective functional groups such as phenolic hydroxyl groups, amide bonds, aromatic rings, etc., and has the characteristics of scale inhibition, corrosion inhibition, antibacterial and fluorescence.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention uses hydroxybenzoic acid hydrazide to open the polysuccinimide ring under alkaline conditions, introduces functional structural fragments into the polyaspartic acid peptide chain, and synthesizes three polyaspartic acid derivatives modified by hydroxybenzoic acid hydrazide, the structural formulas of which are shown below:

[0007]

[0008] Wherein, R2 is -OH, R1 and R3 are H or -OH; A represents an unmodified unit, whose degree of polymerization is n, B represents a modified unit, whose degree of polymerization is m, m+n represents the total degree of polymerization, m / (m+n)×100%=10-40%, that is, the degree of polymerization of hydroxybenzohydrazide accounts for 10-40% of the total degree of polymerization, preferably, the degree of polymerization of hydroxybenzohydrazide accounts for 40% of the total degree of polymerization.

[0009] The present invention uses polysuccinimide (PSI), 4-hydroxybenzohydrazide (4-HBH), 3,4-dihydroxybenzohydrazide (3,4-DHBH), and 3,4,5-trihydroxybenzohydrazide (3,4,5-THBH) as main raw materials. Hydroxybenzohydrazide performs ring-opening modification on polysuccinimide under alkaline conditions to obtain the target product polyaspartic acid-hydroxybenzohydrazide. The specific reaction route is as follows:

[0010]

[0011] R2 is -OH, and R1 and R3 are H or -OH.

[0012] The following steps are involved:

[0013] Hydroxybenzoyl hydrazide and polysuccinimide are dissolved in dimethyl sulfoxide, and then the pH value of the reaction solution is adjusted to weak alkalinity with sodium hydroxide solution, and the reaction is heated and stirred at 60-90°C for 20-30 hours. During the reaction, sodium hydroxide aqueous solution is continuously added to keep the pH value of the reaction solution weakly alkaline, and the solvent is dialyzed and evaporated to obtain the target product.

[0014] Further, the molar ratio of hydroxybenzoic acid hydrazide to the monomer in polysuccinimide is (2.5-3.5): 1. Every 1 mmol of polysuccinimide monomer and 2.5-3.5 mmol of hydroxybenzoic acid hydrazide need to be dissolved in 4 mL of dimethyl sulfoxide.

[0015] Furthermore, the concentration of the sodium hydroxide solution used is 1 mol / L to 2 mol / L.

[0016] Furthermore, the pH value of the dimethyl sulfoxide solution of hydroxybenzoyl hydrazide and polysuccinimide is 8-9; and during the reaction, sodium hydroxide solution is continuously added to maintain the pH value of the reaction solution at 8-9.

[0017] Furthermore, during dialysis, the molecular weight cutoff of the dialysis bag is 500-2000 Da, and the dialysis is performed in distilled water until the conductivity of the distilled water is 1.5-2.5 μS / cm.

[0018] Specifically, the reaction is heated in a water bath at a temperature of 75-80°C.

[0019] The polyaspartic acid derivative modified by hydroxybenzoyl hydrazide is prepared by the preparation method.

[0020] The above-mentioned polyaspartic acid derivative modified by hydroxybenzoyl hydrazide is used as a multifunctional water treatment agent with scale inhibition, corrosion inhibition, antibacterial and fluorescence properties. The bacteria refers to Escherichia coli.

[0021] The above-mentioned polyaspartic acid derivative modified by hydroxybenzoyl hydrazide is used as a scale inhibitor or bacteriostatic agent. The bacteria refers to Escherichia coli.

[0022] The above-mentioned polyaspartic acid derivative modified with hydroxybenzoyl hydrazide is used as a corrosion inhibitor.

[0023] The above-mentioned polyaspartic acid derivative modified with hydroxybenzoyl hydrazide is used as a fluorescent tracer.

[0024] The present invention optimizes the raw material ratio by adjusting the formula and controlling the degree of polymerization, so that the water treatment agent achieves the best scale inhibition effect. When it is finally determined that the degree of polymerization of the modified structural unit accounts for 50% of the total degree of polymerization, the water treatment agent can achieve the best scale inhibition effect. The present invention not only improves its scale inhibition performance, but also improves its corrosion inhibition and antibacterial properties by introducing hydroxybenzoyl hydrazide structural fragments into the polyaspartic acid peptide chain. The present invention also provides the use of the circulating cooling water treatment agent with scale inhibition, corrosion inhibition, antibacterial and fluorescent properties as a scale inhibitor, corrosion inhibitor, antibacterial agent and fluorescent tracer in circulating cooling water.

[0025] The present invention modifies polysuccinimide through a ring-opening reaction to prepare a multifunctional polyaspartic acid derivative having scale inhibition, corrosion inhibition, antibacterial and fluorescence properties. Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1) The present invention introduces hydroxybenzoyl hydrazide structural fragments into polyaspartic acid peptide chains to synthesize a new type of water treatment agent.

[0027] 2) By adjusting the formula ratio, the polymerization degree of the modified structural unit is controlled to account for 50% of the total polymerization degree. The water treatment agent synthesized under this polymerization degree has the best scale inhibition performance.

[0028] 3) First, the structure of the water treatment agent enables it to combine with calcium ions in the solution to form a water-soluble complex, thereby reducing the calcium ion concentration in industrial circulating cooling water, thereby achieving a scale inhibition effect; secondly, the phenolic hydroxyl groups in the structure are easily oxidized, which makes the water treatment agent have a good corrosion inhibition effect; in addition, the water treatment agent can specifically inhibit Escherichia coli, achieving a high efficiency improvement in the scale inhibition, corrosion inhibition and antibacterial properties of polyaspartic acid.

[0029] 4) The synthesis steps of the present invention are simple, and the synthesized product is a new type of phosphorus-free water treatment agent, which can be used to directly detect the concentration of the water treatment agent in the pipeline using a fluorescent tracer by utilizing its optical activity, and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 In: a is the PASP prepared by the present invention 1 H NMR spectrum; b is the PASP-THBH prepared by the present invention 1 H NMR spectrum; c is the PASP-DHBH prepared by the present invention 1 H NMR spectrum; d is the PASP-HBH prepared by the present invention 1 H NMR spectrum;

[0031] Figure 2 The scale inhibition effect of PASP, PASP-THBH, PASP-DHBH and PASP-HBH prepared by the present invention on calcium carbonate scale;

[0032] Figure 3 The scale inhibition effect of PASP, PASP-THBH, PASP-DHBH and PASP-HBH prepared by the present invention on calcium sulfate scale;

[0033] Figure 4 The antibacterial activity of PASP and PASP-THBH prepared by the present invention was tested by coating method;

[0034] Figure 5 The antibacterial activity of PASP and PASP-THBH prepared by the present invention was detected by the inhibition zone method;

[0035] Figure 6 This is the fluorescence spectrum of PASP-THBH prepared in the present invention. DETAILED DESCRIPTION

[0036] 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.

[0037] In the following examples and comparative examples, unless otherwise specified, the raw materials used are directly purchased common commercial products or can be prepared by conventional methods in the art.

[0038] The molecular weight of the polysuccinimide used in the following examples and comparative examples is 7000-8000 and is purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0039] Example 1

[0040] Synthesis of PASP-THBH

[0041] Weigh 10 mmol (0.984 g) of polysuccinimide (PSI) and 30 mmol (5.52 g) of 3,4,5-trihydroxybenzoyl hydrazide (THBH) in a 100 mL round-bottom flask, add 40 mL of DMSO to completely dissolve it, then add 2 mol / L sodium hydroxide aqueous solution to adjust the pH value of the reaction solution to 8-9, then stir and react in a 75°C water bath for 24 hours, and continuously add 2 mol / L sodium hydroxide aqueous solution during the reaction to maintain the pH value of the reaction solution between 8 and 9. After the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 1000 Da, dialyzed in distilled water until the conductivity of the distilled water is reduced to about 2 μS / cm, and the solution is evaporated under reduced pressure to obtain the target product PASP-THBH.

[0042] Synthesis of PASP-DHBH

[0043] Weigh 10 mmol (0.984 g) of polysuccinimide (PSI) and 30 mmol (5.05 g) of 3,4-dihydroxybenzoyl hydrazide (DHBH) in a 100 mL round-bottom flask, add 40 mL of DMSO to completely dissolve it, then add 2 mol / L sodium hydroxide aqueous solution to adjust the pH value of the reaction solution to 8-9, then stir and react in a water bath at 80°C for 24 hours, and continuously add 2 mol / L sodium hydroxide aqueous solution during the reaction to maintain the pH value of the reaction solution between 8 and 9. After the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 1000 Da, dialyzed in distilled water, dialyzed until the conductivity of the distilled water is reduced to about 2 μS / cm, and the solution is evaporated under reduced pressure to obtain the target product PASP-THBH.

[0044] Synthesis of PASP-HBH

[0045] Weigh 10 mmol (0.984 g) of polysuccinimide (PSI) and 30 mmol (4.56 g) of 4-hydroxybenzoyl hydrazide (HBH) in a 100 mL round-bottom flask, add 40 mL of DMSO to completely dissolve it, then add 2 mol / L sodium hydroxide aqueous solution to adjust the pH value of the reaction solution to 8-9, then stir and react in a water bath at 85°C for 48 hours, and continuously add 2 mol / L sodium hydroxide aqueous solution during the reaction to maintain the pH value of the reaction solution between 8 and 9. After the reaction is completed, the reaction solution is placed in a dialysis bag with a molecular weight cutoff of 1000 Da, dialyzed in distilled water until the conductivity of the distilled water is reduced to about 2 μS / cm, and the solution is evaporated under reduced pressure to obtain the target product PASP-HBH.

[0046] Synthesis of PASP

[0047] Take 10 mmol (0.984 g) of polysuccinimide (PSI) in 10 mL of distilled water, place it in a 40°C water bath, and slowly add 10 mL of 1 mol / L sodium hydroxide aqueous solution under stirring. After reacting at this temperature for 24 hours, the resulting solution is loaded into a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed in distilled water until the conductivity of the distilled water is reduced to about 2 μS / cm. The retentate is evaporated by reduced pressure distillation to obtain 1.11 g of the target product PASP with a yield of 95.68%.

[0048] Figure 1 a in the figure is PASP 1 The H NMR spectrum showed typical characteristic peaks of methine and methylene on PASP at δ4.47 and δ2.75, proving that PASP was successfully synthesized.

[0049] Figure 1 b is the target product PASP-THBH 1 The H NMR spectrum showed typical characteristic peaks of methine and methylene on PASP at δ4.47 and δ2.75, and a characteristic peak of benzene ring at δ6.75, which proved that PASP-THBH was successfully prepared. Figure 1 The integral area of ​​hydrogen on the benzene ring around δ6.75 and hydrogen on the methylene side chain of PASP-THBH around δ2.75 was calculated, and the grafting rate of the target product PASP-THBH was 40%.

[0050] Figure 1 c is the target product PASP-DHBH 1 The H NMR spectrum showed typical characteristic peaks of methine and methylene on PASP at δ4.47 and δ2.75, and characteristic peaks of benzene ring at δ6.8 and δ7.2, which proved that PASP-DHBH was successfully prepared. Figure 1 Based on the integrated area calculation of the hydrogen on the benzene ring around the mid-shift δ6.8 and δ7.2 and the hydrogen on the methylene side chain of PASP-DHBH around δ2.75, the grafting rate of the target product PASP-DHBH was 40%.

[0051] Figure 1 Where d is the target product PASP-HBH 1 The H NMR spectrum showed typical characteristic peaks of methine and methylene on PASP at δ4.47 and δ2.75, and characteristic peaks of benzene ring at δ6.9 and δ7.7, which proved that PASP-HBH was successfully prepared. Figure 1The integral area of ​​hydrogen on the benzene ring around δ6.9 and δ7.7 and hydrogen on the side chain methylene of PASP-HBH around δ2.75 was calculated, and the grafting rate of the target product PASP-HBH was 20%.

[0052] Example 2

[0053] The scale inhibition rate of calcium carbonate scale of the product in Example 1 was tested by static scale inhibition method.

[0054] Referring to GB / T16632-2019 "Determination of scale inhibition performance of water treatment agents - Calcium carbonate deposition method", the scale inhibition performance of PASP-THBH against calcium carbonate scale was determined using the static scale inhibition method.

[0055] (1) Take nine 250 mL conical flasks numbered 1-8, and add 10 mL of 6 mg / mL CaCl2 aqueous solution, 10 mL of 3.8 g / L Na2B4O7·10H2O aqueous solution (adjust the initial pH to 9.0), and 10 mL of 18.3 mg / mL NaHCO3 solution into each flask;

[0056] (2) Then, a certain amount of 1 mg / mL PASP-THBH aqueous solution was added to conical flasks No. 3-8, respectively, so that the final concentrations of PASP-THBH in conical flasks No. 3-8 were 10, 20, 30, 40, 50, and 60 mg / L, respectively. At the same time, distilled water was added to conical flasks No. 1-8 to make the total volume of the solution 250 mL;

[0057] (3) Take 25 mL of the solution in bottle 1 and titrate it with 0.01 mol / L EDTA-2Na standard solution to calibrate the Ca 2+ The volume of the standard solution consumed is recorded as V0.

[0058] (4) Then, the No. 2-8 conical flask was reacted in an 80°C water bath for 10 h. After the reaction was completed, the filtrate was filtered and 25 mL of the filtrate was titrated with 0.01 mol / L EDTA-2Na standard solution to calibrate the Ca content. 2+ The volume of the standard solution consumed by the filtrate in bottle No. 2 is recorded as V1, and the volume of the standard solution consumed by the filtrate in conical flasks No. 3-8 is recorded as V2.

[0059] (5) Scale inhibition efficiency It can be calculated according to formula (1):

[0060]

[0061] Repeat the above steps, replace PASP-THBH with PASP-DHBH, PASP-HBH, and PASP to test their scale inhibition rates against calcium carbonate scale, where the scale inhibition rate of PASP against calcium carbonate scale is used as a control.

[0062] Figure 2 The scale inhibition rates of PASP and PASP-THBH, PASP-DHBH and PASP-HBH on calcium carbonate scale at different concentrations. It can be seen from the figure that under the same conditions, the scale inhibition effect of PASP-THBH, PASP-DHBH and PASP-HBH on calcium carbonate scale increases with the increase of hydroxyl groups on the benzene ring. The scale inhibition rate of PASP-THBH on calcium carbonate scale gradually increases with the increase of concentration. The scale inhibition rate of PASP-THBH can reach 91.00% when the concentration is 60 mg / L, which is significantly improved compared with the scale inhibition rate of PASP at a concentration of 60 mg / L (67.73%).

[0063] Example 3

[0064] The calcium sulfate scale inhibition effect of the product in Example 1 was tested by the static scale inhibition method.

[0065] Referring to SY / T5673-2020 "General Technical Conditions for Scale Inhibitors for Oil Fields", the scale inhibition performance of PASP-THBH on calcium sulfate scale was determined by the static scale inhibition method.

[0066] (1) Take eight 250 mL conical flasks, numbered from 1 to 8, and add 50 mL of 7.35 mg / mL CaCl2 solution, 25 mL of 10.4 g / L Na2B4O7·10H2O solution, and 25 mL of 7.1 mg / mL Na2SO4 solution to each flask;

[0067] (2) Add a certain amount of 1 mg / mL PASP-THBH aqueous solution to conical flasks No. 3-8, respectively, so that the final concentration of PASP-THBH in conical flasks No. 3-8 is 1, 2, 3, 4, 5, and 6 mg / L, respectively. At the same time, add distilled water to conical flasks No. 1-8 to make the total volume of the solution 250 mL;

[0068] (3) Take 5 mL of the solution in conical flask No. 1 and titrate it with 0.025 mol / LEDTA-2Na standard solution to calibrate the Ca 2+ The volume of the standard solution consumed is recorded as V0.

[0069] (4) Place conical flasks 2-8 in a 70°C water bath for 6 h. After filtering, take 5 mL of the filtrate and titrate it with 0.025 mol / L LEDTA-2Na standard solution to calibrate the Ca 2+ Concentration, where the volume of the standard solution consumed by the filtrate in conical flask No. 2 is recorded as V1, and the volume of the standard solution consumed by the filtrate in conical flasks No. 3-8 is recorded as V2.

[0070] (5) Scale inhibition efficiency It can be calculated according to formula (1) in Example 2.

[0071] Repeat the above steps, replace PASP-THBH with PASP-DHBH, PASP-HBH, and PASP to determine their scale inhibition rates against calcium sulfate scale, among which the scale inhibition rate of PASP against calcium sulfate scale is used as a control.

[0072] Figure 3 The scale inhibition rates of PASP, PASP-THBH, PASP-DHBH and PASP-HBH at different concentrations on calcium sulfate scale. It can be seen from the figure that the scale inhibition performance of PASP-THBH with 3 hydroxyl groups on the benzene ring and PASP-HBH with 1 hydroxyl group is equivalent to that of PASP, and both can reach about 100% at a lower concentration of 6 mg / L; but when there are 2 hydroxyl groups on the molecular benzene ring, the scale inhibition effect of PASP-DHBH on CaSO4 scale is lower than that of PASP, PASP-THBH and PASP-HBH.

[0073] Example 4

[0074] The corrosion inhibition performance of the product in Example 1 was measured by the rotating coupon method.

[0075] Referring to GB / T1875-2014 "Determination of corrosion inhibition performance of water treatment agents - rotating coupon method", the corrosion inhibition performance of PASP-THBH was determined using the rotating coupon method.

[0076] (1) Prepare the standard solution: dissolve 0.05 mol (7.35 g) of CaCl2·H2O, 0.02 mol (4.93 g) of MgSO4·7H2O, and 0.11 mol (6.58 g) of NaCl in 7 L of water; separately dissolve 0.02 mol (1.68 g) of NaHCO3 in 1 L of water; then mix the two solutions and dilute to 10 L with water to obtain the standard solution;

[0077] (2) Preparation of acid and alkaline washing solutions: Prepare 1000 mL of 1.5 mol / L NaOH solution as alkaline washing solution; take 0.057 mol (8 g) of hexamethylenetetramine and add it to V 浓盐酸(37％) :V H2O =1:4 1000mL mixed solution is prepared as pickling solution;

[0078] (3) Pretreatment of test pieces: 7 groups of 20 # For carbon steel test pieces, wipe off the anti-rust grease with filter paper, then clean it in anhydrous ethanol, dry it with filter paper, dry it in a forced air drying oven at 60℃ for 4h, weigh it after cooling, record it as m1 (accurate to four decimal places), and store it in a desiccator for later use;

[0079] (4) Preparation of test solution: Use the standard solution prepared in step (1) to prepare 2000 mL of PASP-THBH solution with a concentration of 0, 10, 20, 30, 40, and 50 mg / L, respectively; Similarly, use the standard solution prepared in step (1) to prepare 2000 mL of PASP solution with a concentration of 0, 10, 20, 30, 40, and 50 mg / L, respectively;

[0080] (5) Heat the beakers containing the test solution on a rotating plate hanging instrument. When the temperature of the test solution reaches 45°C, hang 1 to 6 groups of carbon steel test pieces treated in step (3) in the six beakers respectively and immerse them completely in the test solution. Adjust the rotation speed to 94 r / min and react at 45°C for 72 h (depending on the test situation, add standard solution in time during the reaction to keep the volume of the test solution at 2000 mL);

[0081] (6) After 72 hours, stop the test, remove the test piece from the beaker on the rotating hanging device, brush it with a brush, and then wash it in the acid cleaning solution prepared in step (2) for 30 seconds, take it out, rinse it with tap water, and then quickly immerse it in the alkaline cleaning solution for 30 seconds, take it out, rinse it with tap water and distilled water in turn, wipe it dry with filter paper, and then soak it in anhydrous ethanol for 3 minutes, take it out, dry it with filter paper, dry it in a forced air drying oven at 60°C for 4 hours, and weigh it after cooling, and record it as m2 (accurate to four decimal places). The seventh group of test pieces (processed in step (3) and not subjected to step (5)) also undergo the above-mentioned acid cleaning, alkaline cleaning, ethanol cleaning, drying and other operations, and weigh it, which is recorded as m2.

[0082] The corrosion rate is expressed as υ, with the unit of mm / a (millimeter / year), and is calculated according to formula (2):

[0083]

[0084] Where:

[0085] m——mass loss of test pieces in groups 1-6 (m2-m1), in grams (g);

[0086] m0——mass loss of the seventh group of test pieces (m2-m1), in grams (g);

[0087] s——surface area of ​​the test piece, in square centimeters (cm 2 );

[0088] ρ——density of the test piece, in grams per cubic centimeter (g / cm 3 );

[0089] t——test time, in hours (h);

[0090] 8760——Number of hours equivalent to a year, in hours per year (h / a);

[0091] 10 – The number of millimeters equivalent to 1 cm, in millimeters per centimeter (mm / cm).

[0092] The corrosion inhibition rate η is calculated according to formula (3):

[0093]

[0094] Where:

[0095] υ0——Corrosion rate of the specimen when the sample concentration is 0 mg / L, in millimeters per year (mm / a);

[0096] υ1——Corrosion rate of the specimen when the sample concentration is 10-50 mg / L, in millimeters per year (mm / a).

[0097] The test results are shown in Table 1:

[0098] Table 1 Corrosion inhibition efficiency of PASP-THBH at different concentrations

[0099]

[0100]

[0101] Table 2 Corrosion inhibition rate of PASP at different concentrations

[0102]

[0103] Example 4 uses the rotating hanging plate method to explore the corrosion inhibition effects of PASP and PASP-THBH at different concentrations. It can be seen from the table that the corrosion inhibition efficiency of PASP-THBH has obvious concentration dependence when the concentration is 0-20 mg / L. When the concentration exceeds 20 mg / L, its corrosion inhibition efficiency gradually decreases with the increase of concentration, but it is higher than the corrosion inhibition rate of PASP at the same concentration. When the concentration is 20 mg / L, the corrosion inhibition rate of PASP-THBH can reach up to 43.52%, which is about twice the corrosion inhibition rate of PASP at the same concentration.

[0104] Example 5

[0105] Determination of the antibacterial activity of PASP-THBH

[0106] (1) Plate spread counting method to measure the antibacterial activity of PASP-THBH against Escherichia coli

[0107] PASP and PASP-THBH stock solutions with a mass concentration of 500 mg / mL were prepared using LB liquid culture medium as the solvent to investigate the inhibitory effects of PASP and PASP-THBH on Escherichia coli.

[0108] Activation of bacterial strains: Take the Escherichia coli (E. coli) strain stored in a -80°C refrigerator, streak it on a fresh solid LB plate (containing 10 g tryptone, 5 g yeast extract, 10 g NaCl and 1.6 g agar powder per 1 liter), and culture it at a constant temperature of 30°C for 24 h.

[0109] Pick a single colony in 5mL LB liquid medium and culture at 30℃, 220r / min for 24h. Add the bacterial solution (80μL) after 24h culture to the sterilized PASP or PASP-THBH solution and dilute to 8mL, so that the final concentration of PASP or PASP-THBH is 20, 40, 60, 80, 100mg / mL respectively; put it in a 37℃ constant temperature incubator, take 50μL of bacterial solution on solid LB medium after 2h, spread the bacterial solution evenly with a coating rod, and then put it in a 37℃ constant temperature incubator for culture; record the number of colonies on the solid culture medium after 24h, and take digital photos of the experimental results.

[0110] Figure 4 The figure shows the antibacterial activity of PASP-THBH at different concentrations against E. coli. It can be seen from the figure that with the increase of PASP-THBH concentration, the survival rate of E. coli shows a significant downward trend. In contrast, with the increase of PASP concentration, the survival rate of E. coli decreases slowly. Overall, at the same concentration, PASP-THBH has a better inhibitory effect on E. coli than PASP. When the concentration of PASP-THBH is 100 mg / mL, the survival rate of E. coli is only 33%.

[0111] (2) Antibacterial activity of PASP-THBH against Escherichia coli measured by inhibition zone method

[0112] Activation of bacterial strains: Take the Escherichia coli (E. coli) strain stored in a -80°C refrigerator, streak it on a fresh solid LB plate (containing 10g tryptic peptone, 5g yeast extract, 10g NaCl and 1.6g agar powder per 1 liter), and culture it at a constant temperature of 30°C for 15h.

[0113] A single colony was inoculated into 5 mL LB liquid medium and cultured overnight at 30°C and 220 r / min.

[0114] Take 1mL of overnight culture solution and transfer it to 100mL LB semi-liquid medium (0.7g agar powder), mix well, and pour it into the LB solid plate prepared in advance. After 30 minutes, spread the sterilized circular filter paper with a diameter of 0.7mm on the LB medium, and drip different concentrations of PASP and PASP-THBH solutions on the filter paper. The compound dose on each filter paper is 50μL, and each sample is repeated three times. After standing for 30 minutes, the above plate is placed in a 30℃ constant temperature incubator for overnight culture. Observe and measure the diameter of the inhibition zone. If there is an obvious colony inhibition zone around the filter paper coated with the agent, it can be determined that PASP or PASP-THBH has an inhibitory effect on the tested strain. Among them, the antibacterial effect of PASP is used as the control group.

[0115] Figure 5 The antibacterial activity of PASP and PASP-THBH against E. coli. The antibacterial diameters of 50 mg / mL and 100 mg / mL PASP against E. coli were both 8.1 mm; while the antibacterial diameters of PASP-THBH against E. coli at a concentration of 100 mg / mL were 26.4 mm and 24.4 mm at a concentration of 50 mg / mL. Compared with PASP, the inhibitory effect of PASP-THBH on E. coli was significantly better than that of PASP.

[0116] Example 6

[0117] Fluorescence spectrum of PASP-THBH

[0118] PASP-THBH aqueous solutions with concentrations of 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mg / L were prepared and recorded as test solutions. The excitation wavelength was fixed at 325 nm (the optimal absorption of PASP-THBH was 325 nm as tested by ultraviolet light), the excitation slit and emission slit were set to 20 nm and 10 nm, respectively, and the emission wavelength and corresponding fluorescence intensity of PASP-THBH at different concentrations were detected by a fluorescence spectrophotometer.

[0119] Figure 6 The relationship between the concentration and fluorescence intensity of PASP-THBH. As can be seen from the figure, the fluorescence intensity of PASP-THBH increases with the increase of concentration, showing a good linear relationship. Therefore, in industrial production, the content of water treatment agent in circulating water can be estimated according to the fluorescence intensity of the aqueous solution in the circulating water pipeline.

[0120] The above-mentioned embodiments only express the implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

[0121] It should be noted that the above embodiments and control examples all belong to the same inventive concept, and the descriptions of the embodiments and control examples have different emphases. For matters not described in detail in the embodiments and control examples, reference may be made to the descriptions in other embodiments and control examples.

Claims

1. A method for preparing a polyaspartic acid derivative modified with hydroxybenzoylhydrazide, characterized in that: The process is as follows: hydroxybenzoic acid hydrazide and polysuccinimide are dissolved in dimethyl sulfoxide, and then the pH value of the reaction solution is adjusted to weak alkalinity with sodium hydroxide solution, and the reaction is heated and stirred at 60-90°C for 20-30 hours. During the reaction, sodium hydroxide solution is continuously added to keep the pH value of the reaction solution weakly alkaline, and the solvent is dialyzed and evaporated to obtain the target product.

2. The method for preparing a polyaspartic acid derivative modified with hydroxybenzoylhydrazide according to claim 1, characterized in that: The hydroxybenzoic acid hydrazide is one or a mixture of any proportion of 4-hydroxybenzoic acid hydrazide, 3,4-dihydroxybenzoic acid hydrazide and 3,4,5-trihydroxybenzoic acid hydrazide, and the molar ratio of hydroxybenzoic acid hydrazide to the monomer in polysuccinamide is (2.5-3.5):

1.

3. The method for preparing a polyaspartic acid derivative modified with hydroxybenzoylhydrazide according to claim 1, characterized in that: The concentration of sodium hydroxide solution is 1 mol / L ~2 mol / L.

4. The method for preparing a polyaspartic acid derivative modified with hydroxybenzoyl hydrazide according to claim 1, characterized in that: Weak alkalinity refers to a pH value of 8~9.

5. The method for preparing a polyaspartic acid derivative modified with hydroxybenzoyl hydrazide according to claim 1, characterized in that: During dialysis, the molecular weight cutoff of the dialysis bag is 500~2000Da, and the dialysis is performed in distilled water until the conductivity of the distilled water is 1.5~2.5 μS / cm.

6. A polyaspartic acid derivative modified with hydroxybenzoyl hydrazide obtained by the preparation method according to any one of claims 1 to 5.

7. Use of the polyaspartic acid derivative modified with hydroxybenzoyl hydrazide as claimed in claim 6 as a multifunctional water treatment agent having scale inhibition, corrosion inhibition, antibacterial and fluorescence properties.

8. Use of the polyaspartic acid derivative modified with hydroxybenzoyl hydrazide as claimed in claim 6 as a scale inhibitor or bacteriostatic agent.

9. Use of the polyaspartic acid derivative modified with hydroxybenzoyl hydrazide as claimed in claim 6 as a corrosion inhibitor.

10. Use of the polyaspartic acid derivative modified with hydroxybenzoyl hydrazide according to claim 6 as a fluorescent tracer.

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