Novel scale inhibitor and preparation method thereof

Abstract

The invention discloses a dendritic polymer, a preparation method thereof and an application of the dendritic polymer as a scale inhibitor, the structural formula of the dendritic polymer scale inhibitor is as shown in formula 1, and n is equal to 200-300 when the dendritic polymer scale inhibitor is # imgabs0 and the formula 1 is as shown in formula 1. Molecules of the prepared scale inhibitor simultaneously have carboxyl, amido and carbonyl chelating functional groups and have sulfonic acid descaling functional groups, so that the scale inhibitor has excellent scale inhibition and dispersion effects on formation of scales such as Ca < 2 + > and Ba < 2 + >. The molecules do not contain non-biodegradable functional groups, so that the scale inhibitor has the advantages of greenness, environmental protection and biodegradability.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials, and particularly relates to a dendritic polymer and a preparation method thereof and application thereof as a scale inhibitor. Background Art

[0002] Scaling is often a key factor in the boiler feed water treatment process that affects the boiler life, increases boiler energy consumption, and even causes boiler explosion in severe cases.

[0003] At present, carbonate scale and sulfate scale are the most common scales in boiler water supply and drainage. The addition of chemical scale inhibitors is the mainstream scale prevention technology for the two types of scales commonly used in industry. Commercial scale inhibitors mainly include poly (acrylic acid), polymaleic acid, polyaspartic acid, polyphosphates, etc. The above scale inhibitors have problems such as single functional groups, lack of descaling function for formed scales, and lack of outstanding inhibitory effect on scale formation. With the improvement of environmental awareness of people around the world, the eutrophication of water bodies caused by the excessive use of phosphorus-based scale inhibition technology has caused people to criticize.

[0004] Therefore, it is urgent to develop green multifunctional scale inhibitors. Polyamino acid polymers are biodegradable, have strong complexation and excellent dispersion properties of macromolecules, and can be effectively used to prevent the formation of CaCO3 and CaSO4 scale. Polyaspartic acid is a scale inhibitor commonly used in industry. However, since it only relies on the coordinated coordination of carboxyl and nitrogen elements in the molecule to inhibit scale, its use pH range is narrow, it is greatly affected by pH and has no descaling function, which limits its use occasions.

[0005] Therefore, it has become a trend in the water treatment industry to develop new multi-functional scale inhibitors with wide pH range and scale removal properties to replace traditional single-functional scale inhibitors. Therefore, the development of green and multifunctional scale inhibitors is of great significance. Summary of the invention

[0006] The purpose of the present invention is to provide a scale inhibitor with high efficiency in inhibiting calcium scale and barium scale and a preparation method thereof by introducing sulfonic acid groups and chelating amines with descaling functions and carbonyl and carboxyl multidentate ligands to address the deficiencies in the prior art.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme: a dendritic polymer, the structural formula of the dendritic polymer is as shown in Formula 1,

[0008]

[0009] Formula 1.

[0010] Furthermore, the dendrimer is prepared by polycondensation reaction using pyruvic acid, diethylenetriamine, paraformaldehyde and sodium bisulfite as raw materials and deionized water as reaction solvent.

[0011] A preparation method of the above-mentioned dendritic polymer adopts the following steps: in a nitrogen gas atmosphere, pyruvic acid, diethylenetriamine, polyformaldehyde and sodium bisulfite are used as raw materials, and deionized water is used as a reaction solvent to carry out a polymer polycondensation reaction; after the reaction is completed, the reaction mixture is concentrated by evaporating the solvent, anhydrous ethanol is added to the concentrated solution to obtain a precipitate, and the precipitate is filtered and dried to obtain the target product.

[0012] Furthermore, the molar ratio of pyruvic acid, diethylenetriamine, paraformaldehyde and sodium bisulfite is 4:1:(5-6):1.

[0013] Furthermore, the reaction temperature of the polymer polycondensation reaction is 40 to 70° C., and the reaction time is 5 to 8 hours.

[0014] Furthermore, the amount of anhydrous ethanol used is 1 / 3 of the concentrated volume.

[0015] A use of the above dendritic polymer as a scale inhibitor.

[0016] Furthermore, n ranges from 200 to 300.

[0017] Furthermore, when the dendrimer is used as a scale inhibitor, the dispersion is over 97.0% at a concentration of 10 mg / L, and the scale inhibition rate for CaCO3, CaSO4 or BaSO4 is over 98%.

[0018] The advantages and beneficial effects of the present invention are as follows: the novel polymer scale inhibitor provided by the present invention is prepared by polycondensation of pyruvic acid, diethylenetriamine, polyformaldehyde and sodium bisulfite. The polymer scale inhibitor molecules of the present invention simultaneously have four groups: chelated amine, carboxyl, carbonyl and sulfonic acid. The carboxyl group is the most important group for inhibiting the formation of calcium scale. The chelated amine group can effectively inhibit the formation of various transition metal scales. The amine group and the carboxyl group can also prevent the formation of various metal scales through multi-dentate chelation. The three work together to inhibit scale and achieve the effect of resisting pH shock. As a result, the scale inhibitor has good dispersibility and scale inhibition performance. The most important thing is that the introduction of the sulfonic acid group enables the scale inhibitor to have a good removal effect on scale.

[0019] The scale inhibitor provided by the present invention does not contain phosphorus in the molecule, which not only reduces the eutrophication of water bodies, but also has good biodegradability, meets the requirements of environmental protection and degradability, and has a good descaling function for formed scale. The present invention effectively solves the problem that conventional agents lack broad-spectrum scale inhibition performance for CaCO3, CaSO4, BaSO4 and other scales. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the infrared spectrum of the new polymer scale inhibitor prepared in Example 1. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0022] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or are inherent to these processes, methods, products or devices.

[0023] Example 1

[0024] Pyruvic acid (44.03 g, 0.5 mol), diethylenetriamine (12.90 g, 0.125 mol), paraformaldehyde (75.08 g, 2.5 mol), sodium bisulfite (13.00 g, 0.125 mol) and 300 mL of deionized water were added to a 500 mL four-necked flask equipped with a thermometer, a nitrogen introduction device, a 100 mL constant pressure dropping funnel, a magnet and a reflux condenser. The reaction temperature was controlled to be 40 ° C. After reacting for 8 hours, the reaction mixture was concentrated to 200 mL by evaporating the solvent, and 66.7 mL of anhydrous ethanol was added to obtain a precipitate. The precipitate was filtered and dried to obtain a yellow powder antiscalant product.

[0025] The target product was tested using a Nicolet iS10 infrared spectrometer. Figure 1 Data shows: 3400cm -1 The absorption peak at 2920cm is the stretching vibration peak of -OH; -1 The absorption peaks at 1300-1500cm are the symmetric and asymmetric stretching vibration peaks of CH in methylene; -1 The absorption peaks at 1600 cm-1 are the bending vibration and CH stretching vibration of the sulfonic acid group. -1 The absorption peak near the C=O vibration peak is 1082cm -1 The absorption peaks are the CNC stretching vibration peaks and the fingerprint peaks of the sulfonic acid group.

[0026] Example 2

[0027] Pyruvic acid (44.03 g, 0.5 mol), diethylenetriamine (12.90 g, 0.125 mol), paraformaldehyde (90.09 g, 3.0 mol), sodium bisulfite (13.00 g, 0.125 mol) and 300 mL of deionized water were added to a 500 mL four-necked flask equipped with a thermometer, a nitrogen introduction device, a 100 mL constant pressure dropping funnel, a magnet and a reflux condenser. The reaction temperature was controlled to be 60 ° C. After reacting for 6 hours, the reaction mixture was concentrated to 200 mL by evaporating the solvent, and 66.7 mL of anhydrous ethanol was added to obtain a precipitate. The precipitate was filtered and dried to obtain a yellow powdery antiscalant product.

[0028] Example 3

[0029] Pyruvic acid (44.03 g, 0.5 mol), diethylenetriamine (12.90 g, 0.125 mol), paraformaldehyde (90.09 g, 3.0 mol), sodium bisulfite (13.00 g, 0.125 mol) and 300 mL of deionized water were added to a 500 mL four-necked flask equipped with a thermometer, a nitrogen introduction device, a 100 mL constant pressure dropping funnel, a magnet and a reflux condenser. The reaction temperature was controlled to be 70 ° C. After reacting for 5 hours, the reaction mixture was concentrated to 200 mL by evaporating the solvent, and 66.7 mL of anhydrous ethanol was added to obtain a precipitate. The precipitate was filtered and dried to obtain a yellow powdery antiscalant product.

[0030] Example 4

[0031] Pyruvic acid (44.03 g, 0.5 mol), diethylenetriamine (12.90 g, 0.125 mol), paraformaldehyde (82.58 g, 2.75 mol), sodium bisulfite (13.00 g, 0.125 mol) and 300 mL of deionized water were added to a 500 mL four-necked flask equipped with a thermometer, a nitrogen introduction device, a 100 mL constant pressure dropping funnel, a magnet and a reflux condenser. The reaction temperature was controlled to be 60 ° C. After reacting for 8 hours, the reaction mixture was concentrated to 200 mL by evaporating the solvent, and 66.7 mL of anhydrous ethanol was added to obtain a precipitate. The precipitate was filtered and dried to obtain a light yellow powder antiscalant product.

[0032] Example 5

[0033] Pyruvic acid (44.03 g, 0.5 mol), diethylenetriamine (12.90 g, 0.125 mol), paraformaldehyde (82.58 g, 2.75 mol), sodium bisulfite (13.00 g, 0.125 mol) and 300 mL of deionized water were added to a 500 mL four-necked flask equipped with a thermometer, a nitrogen introduction device, a 100 mL constant pressure dropping funnel, a magnet and a reflux condenser. The reaction temperature was controlled to be 70 ° C. After reacting for 8 hours, the reaction mixture was concentrated to 200 mL by evaporating the solvent, and 66.7 mL of anhydrous ethanol was added to obtain a precipitate. The precipitate was filtered and dried to obtain a yellow powder antiscalant product.

[0034] The scale inhibition rate of the scale inhibitor prepared in the above Examples 1 to 5 was determined by comparing it with the commonly used industrial scale inhibitors 2-hydroxyphosphonoacetic acid (HPAA) and ethylenediaminetetramethylenephosphonic acid (EDTMPA) on calcium carbonate, calcium sulfate and barium sulfate scales as follows: Calcium carbonate scale inhibition performance test The scale inhibition performance of the scale inhibitor prepared in Examples 1 to 5 was evaluated according to the "Determination of scale inhibition performance of water treatment agents - calcium carbonate precipitation method" (GB / T16632-2019), and the corresponding scale inhibition rate was calculated. The scale inhibition performance of CaSO4 scale and BaSO4 scale was tested in accordance with the above standards.

[0035] The homemade scale inhibitor (solvent is water), HPAA and EDTMPA scale inhibitor solutions of the same mass concentration (20 mg / L) were accurately prepared in three reagent bottles for use.

[0036] Calcium carbonate: Take 200mL of deionized water in a 250mL volumetric flask and add the pre-prepared CaCl2 solution to make Ca 2+ Content: 96.00mg·mL -1 Accurately add a certain amount of antiscalant solution, let it stand for 10 minutes, then add the pre-prepared Na2CO3 solution while shaking to make CO3 2- Content: 150.72mg·mL -1 Dilute to the mark with deionized water and place in a ground-mouth conical flask. Place in a water bath at 50℃±1℃ for half an hour and then let stand for 16 hours.

[0037] Calcium sulfate: Take 150mL of deionized water in a 250mL volumetric flask and add the pre-prepared CaCl2 solution to make Ca 2+ Content: 3000mg·mL -1 Accurately add a certain amount of antiscalant solution, let it stand for 10 minutes, then add the pre-prepared Na2SO4 solution while shaking to make SO4 2- Content: 7335mg·mL -1Dilute to the mark with deionized water and place in a ground-mouth conical flask. Place in a water bath at 50℃±1℃ for half an hour and then let stand for 24 hours.

[0038] Barium sulfate: Take 200mL of deionized water in a 250mL volumetric flask and add the pre-prepared BaCl2 solution to make Ba 2+ Content: 2.8mg·mL -1 Accurately add a certain amount of antiscalant solution, let it stand for 10 minutes, and then add the pre-prepared Na2SO4 while shaking. 4 Solution, SO4 2- Content: 2.06 mg·mL -1 Dilute to the mark with deionized water and place in a ground-mouth conical flask. Place in a water bath at 50℃±1℃ for half an hour and then let stand for 24 hours.

[0039] After the reaction is completed, the solution is cooled to room temperature and filtered with quantitative filter paper. The filtrates of CaCO3, CaSO4 and BaSO4 are titrated with ethylenediaminetetraacetic acid (EDTA) standard solution to determine Ca 2+ and Ba 2+ The scale inhibition performance is shown in Table 1.

[0040] The evaluation of the dispersibility of the scale inhibitor prepared in Example 1-5 with HPAA (2-hydroxyphosphonoacetic acid) and EDTMPA (ethylenediaminetetramethylenephosphonic acid) was carried out according to the draft for comments on the determination method of dispersibility of water treatment agents Part 1: Dispersible kaolin method. The dispersibility is shown in Table 2.

[0041] In the pH shock resistance experiment, hydrochloric acid was used as a pH regulator and a pH meter was used as a measuring tool. Taking Example 1 as an example, the scale inhibition performance of the homemade scale inhibitor with HPAA (2-hydroxyphosphonoacetic acid) and EDTMPA (ethylenediaminetetramethylenephosphonic acid) at different pH values ​​was investigated. The scale inhibition performance of the scale inhibitor prepared in Example 1 with HPAA (2-hydroxyphosphonoacetic acid) and EDTMPA (ethylenediaminetetramethylenephosphonic acid) at different pH values ​​is shown in Table 3.

[0042] It can be seen from Table 1 that the scale inhibition rate of the scale inhibitors prepared in Examples 1 to 5 for CaCO3, CaSO4 and BaSO4 scale under the same conditions is significantly better than that of the commonly used HPAA and EDTMPA scale inhibitors on the market. It can be seen from Table 2 that the dispersibility of the scale inhibitors prepared in Examples 1 to 5 for CaCO3, CaSO4 and BaSO4 scale under the same conditions is also significantly better than that of the commonly used HPAA and EDTMPA scale inhibitors on the market. It can be seen from Table 3 that the homemade scale inhibitor has excellent scale inhibition performance in a wide pH range of use.

[0043] Table 1 Static scale inhibition performance test

[0044]

[0045] Table 2 Dispersion performance test

[0046]

[0047] Table 3 pH range of use

[0048]

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A dendritic polymer, characterized in that: The structural formula of the dendrimer is shown in Formula 1, Formula 1.

2. The dendrimer according to claim 1, characterized in that: The dendritic polymer is prepared by polycondensation reaction using pyruvic acid, diethylenetriamine, paraformaldehyde and sodium bisulfite as raw materials and deionized water as reaction solvent.

3. A method for preparing the dendritic polymer according to claim 1 or 2, characterized in that The following steps are adopted: in a nitrogen atmosphere, pyruvic acid, diethylenetriamine, polyformaldehyde and sodium bisulfite are used as raw materials, and deionized water is used as a reaction solvent to carry out a polymer polycondensation reaction; after the reaction is completed, the reaction mixture is concentrated by evaporating the solvent, and anhydrous ethanol is added to the concentrated solution to obtain a precipitate; the precipitate is filtered and dried to obtain the target product.

4. The preparation method according to claim 3, characterized in that: The molar ratio of the pyruvic acid, diethylenetriamine, paraformaldehyde and sodium bisulfite is 4:1:(5-6):

1.

5. The preparation method according to claim 3, characterized in that: The reaction temperature of the polymer polycondensation reaction is 40-70° C., and the reaction time is 5-8 hours.

6. The preparation method according to claim 3, characterized in that: The usage amount of the anhydrous ethanol is 1 / 3 of the concentrated volume.

7. Use of the dendritic polymer according to claim 1 or 2 as a scale inhibitor.

8. The use according to claim 7, characterized in that: The range of n is 200-300.

9. The use according to claim 7, characterized in that: When the dendritic polymer is used as a scale inhibitor, at a concentration of 10 mg / L, the dispersibility exceeds 97.0%, and the scale inhibition rate for CaCO3, CaSO4 or BaSO4 scale is above 98%.

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