A corrosion and scale inhibitor containing heterocyclic compounds

Abstract

This invention relates to the field of corrosion and scale inhibition technology, specifically to a corrosion and scale inhibitor containing a heterocyclic compound. The heterocyclic compound is an imidazoline derivative grafted onto a polyaspartic acid polymer. The structural formula of the imidazoline derivative is as follows: R is a C1-C1 substituent or unsubstituent substituent. 30 The hydrocarbon group, wherein the substituent is one or more of hydroxyl, carboxyl, alkoxy, nitro, amino, sulfonic acid, aldehyde, and cyano groups, has a significant synergistic effect when heterocyclic compounds are used in combination with organophosphorus scale and corrosion inhibitors, resulting in better scale and corrosion inhibition and corrosion suppression.

Description

Technical Field

[0001] This invention relates to the field of corrosion and scale inhibition technology, specifically to a corrosion and scale inhibitor containing heterocyclic compounds. Background Technology

[0002] With the rapid development of industry, industrial water consumption, especially industrial circulating water, is increasing year by year. In actual industrial production, with the long-term operation of circulating equipment, problems such as pipe corrosion and scaling often occur in circulating water systems. This not only results in low heat exchange efficiency but also significantly shortens equipment lifespan, reduces production capacity, and increases industrial costs. Solving these problems is urgent. The most common method in industry is to add scale and corrosion inhibitors to the circulating cooling water system to achieve the purpose of scale inhibition and corrosion inhibition. As early as the mid-20th century, natural polymers such as lignin and starch were used as scale inhibitors in industry, but their scale inhibition performance was poor and the dosage was too large. They were gradually replaced by newly emerging synthetic scale inhibitors. However, currently, single scale inhibitors often have unsatisfactory scale inhibition performance and are difficult to meet the application requirements. Summary of the Invention

[0003] Purpose of the invention: In view of the above-mentioned technical problems, the present invention proposes a corrosion and scale inhibitor containing heterocyclic compounds.

[0004] The technical solution adopted is as follows:

[0005] A corrosion and scale inhibitor containing a heterocyclic compound, wherein the heterocyclic compound is an imidazoline derivative grafted with modified polyaspartic acid polymer;

[0006] The structural formula of the imidazoline derivative is as follows:

[0007]

[0008] R is a C1-C group with or without substituents. 30 hydrocarbon group;

[0009] The substituent is one or more of the following: hydroxyl, carboxyl, alkoxy, nitro, amino, sulfonic acid, aldehyde, and cyano.

[0010] Furthermore, R is C8-C 20 Alkyl or C8-C 20 alkenyl;

[0011] The C8-C 20 Alkyl or C8-C 20 The alkenyl group may be substituted with or not substituted with a sulfonic acid group.

[0012] Furthermore, R is a sulfonic acid group substituted C8-C 20 alkyl.

[0013] Furthermore, the preparation method of the heterocyclic compound is as follows:

[0014] Mix RCOOH and diethylenetriamine evenly. Under nitrogen protection, first heat to 150-170℃ and maintain the temperature for 2-4 hours. Then heat to 200-220℃ and continue the reaction for 2-4 hours. Stop heating and drain the water generated during the reaction. Allow to cool naturally to room temperature to obtain the imidazoline derivative. Add polysuccinimide and the imidazoline derivative to water and heat to 40-60℃. Use ultrasonic vibration to disperse evenly. Adjust the pH of the solution to 9-10 with sodium hydroxide solution. After reacting for 24-36 hours, first adjust the pH of the solution to 6-7 with hydrochloric acid, then precipitate with anhydrous ethanol. Let stand for 12-24 hours, filter, and wash the obtained solid several times with anhydrous ethanol and then dry.

[0015] Furthermore, the molar ratio of RCOOH to diethylenetriamine is 1:1-1.3.

[0016] Furthermore, the weight ratio of the polysuccinimide to the imidazoline derivative is 1:0.05-0.1.

[0017] Furthermore, it also includes organophosphorus scale and corrosion inhibitors.

[0018] Furthermore, the organophosphorus scale and corrosion inhibitor includes any one or more combinations of ATMP, HEDP, DTPMPA, EDTMPS, and HPAA.

[0019] Furthermore, the weight ratio of the heterocyclic compound to the organophosphorus scale and corrosion inhibitor is 1:0.5-1.

[0020] Furthermore, the amount of the corrosion and scale inhibitor used is 10-50 ppm.

[0021] The beneficial effects of this invention are:

[0022] This invention provides a corrosion and scale inhibitor containing a heterocyclic compound. Specifically, the heterocyclic compound is an imidazoline derivative grafted onto a modified polyaspartic acid polymer. The imidazoline derivative contains a nitrogen-containing five-membered heterocycle, a long-chain alkyl group, and a sulfonic acid group. The atoms with lone pairs of electrons (N, O, S, etc.) in the nitrogen-containing five-membered heterocycle readily form coordination bonds with metal atoms, thereby undergoing chemisorption to slow down corrosion. The sulfonic acid group, as a hydrophilic group, can also increase the solubility of the compound, thereby improving the corrosion inhibition performance. The long-chain alkyl group, as a hydrophobic branch, can form a hydrophobic film, effectively preventing further erosion by the corrosive medium. The heterocyclic compound, when used in combination with an organophosphorus scale and corrosion inhibitor, has a significant synergistic effect, resulting in better scale and corrosion inhibition and corrosion suppression. Attached Figure Description

[0023] Figure 1The images show the blank group, control group, and experimental group after continuous corrosion at 70°C for 12 hours in the corrosion solution during the performance test. It can be observed that the 16Mn steel sheet without corrosion and scale inhibitor is severely corroded, while the 16Mn steel sheet with commercially available polyaspartic acid as corrosion and scale inhibitor is visibly corroded. The 16Mn steel sheet with the heterocyclic compound prepared in Example 1 as corrosion and scale inhibitor shows virtually no corrosion traces. Detailed Implementation

[0024] Unless otherwise specified in the examples, the conditions were performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. Techniques not mentioned in this invention refer to existing technologies. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.

[0025] Example 1

[0026] A corrosion and scale inhibitor comprising a heterocyclic compound and an organophosphorus scale and corrosion inhibitor DTPMPA in a weight ratio of 1:0.5.

[0027] The heterocyclic compound is an imidazoline derivative-grafted modified polyaspartic acid polymer, and its preparation method is as follows:

[0028]

[0029] 364.54 g of 18-sulfonic acid octadecanoic acid and 134.12 g of diethylenetriamine were added to a reaction flask equipped with a thermometer, stirrer, and condenser. After stirring and mixing thoroughly, nitrogen gas was introduced for protection. The temperature was first raised to 165°C and maintained for 3 hours, then raised to 220°C and maintained for another 4 hours before stopping heating. Water generated during the reaction was promptly drained, and the mixture was allowed to cool naturally to room temperature to obtain an imidazoline derivative. 100 g of polysuccinimide and 8 g of the imidazoline derivative were added to 500 mL of water, heated to 50°C, and ultrasonically vibrated for 60 minutes to ensure uniform dispersion. The pH of the solution was adjusted to 9 with 0.1 M sodium hydroxide solution, and the reaction was stirred for 24 hours. The pH of the solution was first adjusted to 7 with 0.1 M hydrochloric acid, and then 5 L of anhydrous ethanol was added for precipitation. After standing for 24 hours, the mixture was filtered, and the resulting solid was washed three times with anhydrous ethanol and then transferred to a vacuum dryer at 60°C for 10 hours.

[0030] Example 2

[0031] The method is basically the same as in Example 1, except that the corrosion and scale inhibitor includes a heterocyclic compound and an organophosphorus scale and corrosion inhibitor DTPMPA in a weight ratio of 1:0.6.

[0032] Example 3

[0033] The method is basically the same as in Example 1, except that the corrosion and scale inhibitor includes a heterocyclic compound and an organophosphorus scale and corrosion inhibitor DTPMPA in a weight ratio of 1:0.7.

[0034] Example 4

[0035] The method is basically the same as in Example 1, except that the corrosion and scale inhibitor includes a heterocyclic compound and an organophosphorus scale and corrosion inhibitor DTPMPA in a weight ratio of 1:0.8.

[0036] Example 5

[0037] The method is basically the same as in Example 1, except that the corrosion and scale inhibitor includes a heterocyclic compound and an organophosphorus scale and corrosion inhibitor DTPMPA in a weight ratio of 1:0.9.

[0038] Example 6

[0039] The method is basically the same as in Example 1, except that the corrosion and scale inhibitor includes a heterocyclic compound and an organophosphorus scale and corrosion inhibitor DTPMPA in a weight ratio of 1:1.

[0040] Comparative Example 1:

[0041] The experiment was essentially the same as in Example 1, except that commercially available polyaspartic acid (brand: Changyao, model: CY-D2) was used instead of the heterocyclic compound.

[0042] Comparative Example 2:

[0043] It is basically the same as Example 1, except that the corrosion and scale inhibitors only include heterocyclic compounds.

[0044] Comparative Example 3:

[0045] The method is basically the same as in Example 1, except that the corrosion and scale inhibitor only includes the organophosphorus scale and corrosion inhibitor DTPMPA.

[0046] Performance testing:

[0047] The corrosion and scale inhibitors in Examples 1-6 and Comparative Examples 1-3 of the present invention were used as samples for scale inhibition performance testing, and the sample dosage was 10 ppm.

[0048] ①The scale inhibition performance of water treatment agents was determined according to (GB / T16632-2008) "Determination of scale inhibition performance of water treatment agents by calcium carbonate deposition method".

[0049] The scale inhibition performance of water treatment agents was determined according to (GB / T22626-2008) "Determination of scale inhibition performance of water treatment agents - calcium phosphate deposition method".

[0050] The scale inhibition performance of water treatment agents against CaSO4 was tested using the static scale inhibition method. Experimental water samples were prepared to allow CaSO4 to form a scale-inhibiting agent. 2+ (Calculated as CaSO4) is 2040 mg / L, SO4 2- The concentration of CaSO4 was 2040 mg / L. The sample was added to the solution, heated in a constant temperature water bath at 80°C for 10 hours, allowed to stand and cooled to room temperature, filtered, and the supernatant was taken for testing. The water sample was tested by EDTA titration and the scale inhibition rate was calculated.

[0051] The formula for scale inhibition rate is as follows:

[0052] η=[(V x -V o ) / (V1-V o )]×100%,

[0053] Where: V x The volume of EDTA solution consumed by the water sample after heating the sample;

[0054] V1 represents the volume of EDTA solution consumed by the water sample before the experiment.

[0055] V0 is the volume of EDTA solution consumed by the water sample after heating without adding the sample.

[0056] The test results are shown in Table 1 below:

[0057] Table 1:

[0058]

[0059] As shown in Table 1 above, the corrosion and scale inhibitor provided by the present invention has good scale inhibition efficiency for CaCO3, Ca3(PO4)2 and CaSO4.

[0060] ② Weigh 0.2g CaCl2, 0.2g MgCl2·6H2O, 0.2g NaHCO3, 0.0882g Na2SO4, and 0.6g NaCl into a beaker containing 200ml of deionized water, stir well with a glass rod, and prepare three portions. Adjust the pH value to 4 with dilute hydrochloric acid to serve as corrosion solutions. The blank group does not contain any corrosion and scale inhibitor, the control group contains commercially available polyaspartic acid (brand: Changyao, model: CY-D2), and the experimental group contains the heterocyclic compound prepared in Example 1. The amount added is 50ppm for all groups.

[0061] First, use 100... # Sand it with sandpaper, then use 500 grit sandpaper. #Sand the surface, wash it with tap water, rinse it with deionized water, and finally apply anhydrous ethanol to the surface. After air drying, place it in the corrosion solutions of the blank group, control group, and experimental group respectively, and corrode it continuously at 70℃ for 12 hours. After removal, wash it with deionized water and anhydrous ethanol, dry it, and observe the surface corrosion. For details, please see [link to documentation]. Figure 1 .

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A corrosion and scale inhibitor containing a heterocyclic compound, characterized in that, The heterocyclic compound is an imidazoline derivative grafted modified polyaspartic acid polymer; The structural formula of the imidazoline derivative is as follows: It also includes organophosphorus scale and corrosion inhibitors; The weight ratio of the heterocyclic compound to the organophosphorus scale and corrosion inhibitor is 1:0.5-1; The preparation method of the heterocyclic compound is as follows: Mix 18-sulfonic acid octadecanoic acid with diethylenetriamine until homogeneous. Under nitrogen protection, first heat to 150-170℃ and maintain the temperature for 2-4 hours. Then heat to 200-220℃ and maintain the temperature for another 2-4 hours. Stop heating and drain the water generated during the reaction. Allow to cool naturally to room temperature to obtain an imidazoline derivative. Add polysuccinimide and the imidazoline derivative to water and heat to 40-60℃. Use ultrasonic vibration to disperse the derivative evenly. Adjust the pH of the solution to 9-10 with sodium hydroxide solution. After reacting for 24-36 hours, first adjust the pH of the solution to 6-7 with hydrochloric acid, then precipitate with anhydrous ethanol. Let stand for 12-24 hours, filter, and wash the obtained solid with anhydrous ethanol several times and then dry. The organophosphorus scale and corrosion inhibitor is DTPMPA; The weight ratio of the polysuccinimide to the imidazoline derivative is 1:0.05-0.1; The amount of corrosion and scale inhibitor used is 10-50 ppm.

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