CN113045700B

CN113045700B - Terpolymer and preparation method and application thereof

Info

Publication number: CN113045700B
Application number: CN202110233119.3A
Authority: CN
Inventors: 吉远辉; 唐帅
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2021-03-03
Filing date: 2021-03-03
Publication date: 2022-03-08
Anticipated expiration: 2041-03-03
Also published as: CN113045700A

Abstract

The invention discloses a terpolymer and a preparation method and application thereof, wherein the terpolymer is synthesized by itaconic acid, sodium allylsulfonate, acrylamide molecules, a molecular regulator and other substances, the terpolymer with the optimal performance is obtained by optimizing synthesis conditions, and the terpolymer is used as a scale inhibitor. The ternary polymer provided by the invention has a remarkable effect in inhibiting calcium sulfate scale, and the highest inhibition rate of the ternary polymer PIA-SAS-AM on the calcium sulfate scale can reach 99.51%.

Description

Terpolymer and preparation method and application thereof

Technical Field

The invention relates to the technical field of polymer synthesis, in particular to a terpolymer and a preparation method and application thereof.

Background

Scaling on the surface of a heat exchanger is a long-term and serious problem in industries such as petroleum, seawater desalination, salt industry and the like. The poor heat conductivity of the scale and the large adhesion of the scale to the wall surface of the heat exchanger cause the problems of low production efficiency, high production cost, energy loss and the like. In severe cases, the scale accumulated on the surface of the pipeline can be removed only by the water jet and the acid washing, however, in this case, the plant needs to be shut down, thus causing a serious economic loss. Typically, scale is composed primarily of calcium carbonate, calcium sulfate and calcium phosphate, with calcium sulfate being one of the major components of the scale due to its inverse temperature properties of solubility. Calcium sulfate has three main crystal forms: calcium sulfate dihydrate, calcium sulfate hemihydrate and calcium sulfate anhydrite, which are mainly present in an environment above 98 ℃. Therefore, calcium sulfate dihydrate is the most stable at room temperature and is the main component of calcium sulfate scale.

At present, the main methods for preventing the formation of calcium sulfate dihydrate scale on the surface of a heat exchanger comprise mechanical cleaning, acidification, addition of a scale inhibitor, a threshold inhibitor and the like. In these methods, the scale inhibitors are widely used industrially because of their crystal nucleation and growth inhibiting effect and their economically efficient scale removal characteristics. The existing scale inhibitor comprises a polymeric type and a non-polymeric type, and because functional groups of polymers have stronger complexation and macromolecules have excellent dispersion characteristics, a small amount of polymer concentration can also prevent scaling. In recent years, with the improvement of environmental awareness and the demand of people on environmental protection chemicals, the synthesis research of the phosphorus-free high-efficiency scale inhibitor has important practical significance and direct economic benefit.

Current research indicates that the scale inhibition performance of polymers depends mainly on their functional groups, structure and molecular weight. The most common functional groups are carboxylic acids, sulfonic acids, amides, and hydroxyl groups. Since the carboxyl groups can complex with calcium ions in solution, the performance of the polymeric scale inhibitor is generally related to its carboxyl group content. However, the corrosion inhibiting properties of the polymer are impaired due to the weak acidity of the carboxyl groups in the polymer. Therefore, other functional groups must be added to modify the polymer to obtain greater scale inhibition efficiency. In recent years, chemical modification has become a reliable option for improving the scale inhibition performance of scale inhibitors.

Disclosure of Invention

The purpose of the invention is as follows: in view of the scaling problem widely existing in the industry, the invention aims to solve the technical problem of providing a novel ternary polyitaconic acid-sodium allylsulfonate-acrylamide (PIA-SAS-AM) polymer; the technical problem to be solved by the invention is to provide a preparation method of the novel terpolymer PIA-SAS-AM; the invention finally aims to solve the technical problem of providing the application of the novel terpolymer PIA-SAS-AM in preparing a scale inhibitor and in the industry of inhibiting or removing calcium sulfate scale.

The technical scheme is as follows: in order to solve the technical problems, the synthesis method of the terpolymer PIA-SAS-AM comprises the following steps:

(1) fully stirring itaconic acid, sodium allylsulfonate, acrylamide, a molecular regulator and water at room temperature to obtain a mixed solution;

(2) preparing an initiator solution, and transferring the initiator solution to a constant-pressure dropping funnel;

(3) vacuumizing the mixed solution obtained in the step (1), and introducing inert gas for protection;

(4) slowly dripping the initiator solution in the constant-pressure dropping funnel in the step (2) into the mixed solution treated in the step (3), and reacting at high temperature to obtain a polymer solution;

(5) precipitating and washing the polymer solution by using absolute ethyl alcohol to obtain a precipitation product;

(6) and (3) drying the precipitation product in a vacuum drying oven to obtain powdery polyitaconic acid-sodium allylsulfonate-acrylamide, namely the terpolymer.

Further, in the step (1), the mass ratio of itaconic acid, sodium allyl sulfonate and acrylamide is 1-2: 1-2: 1 to 2.

Further, in the step (1), the molecular regulator is one or two of isopropanol and isopropyl mercaptan, and the mass of the molecular regulator is 2wt% -10 wt% of the total mass of itaconic acid, sodium allylsulfonate and acrylamide.

Further, in the step (2), the initiator is one or two of ammonium persulfate and potassium persulfate, and the mass of the initiator is 4wt% -12 wt% of the total mass of the itaconic acid, the sodium allylsulfonate and the acrylamide; in the step (3), the inert gas is nitrogen or argon.

Further, in the step (4), the stirring speed is 600rpm, the dropping time of the initiator solution is 1-1.5 h, the high-temperature reaction time is 0.5-4.5 h, and the temperature of the high-temperature reaction is 50-100 ℃.

Further, in the step (5), the volume ratio of the absolute ethyl alcohol to the polymer solution is 1: 4.

further, in the step (6), the vacuum drying temperature is 50 ℃, and the drying time is 48 h.

The terpolymer PIA-SAS-AM is prepared by the synthetic method.

The invention relates to an application of a terpolymer PIA-SAS-AM in preparing a scale inhibitor.

The invention relates to an application of a terpolymer PIA-SAS-AM in inhibiting or removing calcium sulfate scale.

The synthetic route of the terpolymer PIA-SAS-AM is as follows:

mechanism of scale inhibition: the scaling process of insoluble salts such as calcium sulfate can be divided into two steps, the generation of crystal nuclei and crystal growth. The carboxylic acid groups can bind to calcium ions in solution due to their strong chelating ability and excellent affinity. Therefore, the synthesized terpolymer PIA-SAS-AM in the research can form a soluble complex with calcium ions in a solution through-COOH, so that the concentration of free calcium ions is reduced, the supersaturation degree is reduced, and the generation of crystal nuclei is inhibited. The terpolymer PIA-SAS-AM contains-COO-and-SO₃The ternary polymer PIA-SAS-AM can be adsorbed on calcium sulfate crystals, the charge density between the ternary polymer PIA-SAS-AM and crystal nuclei is increased, the ternary polymer PIA-SAS-AM can penetrate through a hydration layer around calcium ions and sulfate more easily and is adsorbed on the surface of a scaling substance and active growth points of crystal lattices, and therefore the scale inhibition performance of the ternary polymer PIA-SAS-AM is enhanced. Due to the existence of the sulfonic acid group, the temperature resistance and scale inhibition performance of the copolymer are improved, and the scale inhibition rate can be kept for a long time at high temperature. In addition, the flexibility of the structure of the terpolymer PIA-SAS-AM can be improved by the connection of the amide group and the sulfonic group, so that the interaction between the terpolymer PIA-SAS-AM and the structure crystal is enhanced, and the inhibition effect of the terpolymer PIA-SAS-AM on the formation of calcium sulfate scale is improved.

Has the advantages that: compared with the prior art, the invention has the advantages that: the invention adopts an aqueous solution polymerization method to synthesize a novel terpolymer scale inhibitor, namely terpolymer PIA-SAS-AM, and the terpolymer scale inhibitor has good heat resistance, salt tolerance and stability. The novel terpolymer scale inhibitor designed and synthesized by the invention is easy to repeat and characterize, has a good inhibition effect on calcium sulfate scale, and the highest inhibition rate of the terpolymer PIA-SAS-AM on the calcium sulfate scale can reach 99.51%.

Drawings

FIG. 1 shows an IR spectrum of a terpolymer PIA-SAS-AM.

FIG. 2 is a NMR spectrum of itaconic acid.

FIG. 3 is a nuclear magnetic resonance hydrogen spectrum of sodium allylsulfonate.

FIG. 4 is a NMR spectrum of acrylamide.

FIG. 5 shows the NMR spectrum of the terpolymer PIA-SAS-AM.

FIG. 6 is a thermogravimetric analysis profile of the terpolymer PIA-SAS-AM.

FIG. 7 is a gel permeation chromatogram of the terpolymer PIA-SAS-AM.

FIG. 8 is a water solubility evaluation chart of a terpolymer PIA-SAS-AM.

FIG. 9 is an XRD pattern of a terpolymer PIA-SAS-AM performance evaluation product; wherein the addition amounts are respectively (a)0 mg/L; (b)4 mg/L; (c)8 mg/L; (d)12 mg/L.

FIG. 10 is an SEM image of a terpolymer PIA-SAS-AM performance evaluation product; wherein the addition amounts are respectively (a)0 mg/L; (b)4 mg/L; (c)8 mg/L; (d)12 mg/L.

FIG. 11 shows the static scale inhibition evaluation results of the terpolymer PIA-SAS-AM and the common polymer PAA at the same concentration; wherein, (a) is a terpolymer PIA-SAS-AM, and (b) is a common polymer PAA.

FIG. 12 is a graph comparing the calcium sulfate inhibition of the same concentration of the terpolymer PIA-SAS-AM with the commonly used polymer PAA.

Detailed Description

The technical solution of the present invention is further described in detail below with reference to the accompanying drawings.

The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

EXAMPLE 1 Synthesis of terpolymer PIA-SAS-AM

In a three-necked flask with a reflux condenser, 4g of itaconic acid, 2g of sodium allylsulfonate, 2g of acrylamide, 0.32g of isopropanol as a molecular regulator, and 50ml of distilled water were placed and sufficiently stirred at room temperature. 0.80g of ammonium persulfate was dissolved in 50ml of distilled water, and charged into a constant pressure dropping funnel. Slowly dropwise adding an ammonium persulfate solution under the nitrogen atmosphere, heating to 70 ℃, and reacting for 4 hours at constant temperature. The reacted solution was subjected to alcohol precipitation and washing with 400ml of anhydrous ethanol, and the product was dried in a vacuum oven at 50 ℃ for 48 hours to obtain 3.1602g of terpolymer PIA-SAS-AM with a yield of 39.50%.

Example 2 Synthesis of terpolymer PIA-SAS-AM

2g of itaconic acid, 2g of sodium allylsulfonate, 2g of acrylamide, 0.24g of isopropanol as a molecular regulator and 50ml of distilled water were put in a three-necked flask equipped with a reflux condenser, and sufficiently stirred at room temperature. 0.60g of ammonium persulfate was dissolved in 50ml of distilled water and charged into a constant pressure dropping funnel. Slowly dropwise adding an ammonium persulfate solution under the nitrogen atmosphere, heating to 70 ℃, and reacting for 4 hours at constant temperature. The reacted solution was subjected to alcohol precipitation and washing with 400ml of absolute ethanol, and the product was dried in a vacuum oven at 50 ℃ for 48 hours to obtain 5.1966g of a terpolymer PIA-SAS-AM with a yield of 86.61%.

Example 3 Synthesis of terpolymer PIA-SAS-AM

2g of itaconic acid, 4g of sodium allylsulfonate, 2g of acrylamide, 0.32g of isopropanol as a molecular regulator and 50ml of distilled water were put in a three-necked flask equipped with a reflux condenser, and sufficiently stirred at room temperature. 0.80g of ammonium persulfate was dissolved in 50ml of distilled water, and charged into a constant pressure dropping funnel. Slowly dropwise adding an ammonium persulfate solution under the nitrogen atmosphere, heating to 70 ℃, and reacting for 4 hours at constant temperature. The reacted solution was subjected to alcohol precipitation and washing with 400ml of absolute ethanol, and the product was dried in a vacuum oven at 50 ℃ for 48 hours to obtain 4.6907g of a terpolymer PIA-SAS-AM with a yield of 58.63%.

Example 4 Synthesis of terpolymer PIA-SAS-AM

2g of itaconic acid, 2g of sodium allylsulfonate, 4g of acrylamide, 0.32g of isopropanol as a molecular regulator and 50ml of distilled water were put in a three-necked flask equipped with a reflux condenser, and sufficiently stirred at room temperature. 0.80g of ammonium persulfate was dissolved in 50ml of distilled water, and charged into a constant pressure dropping funnel. Slowly dropwise adding an ammonium persulfate solution under the nitrogen atmosphere, heating to 70 ℃, and reacting for 4 hours at constant temperature. The reacted solution was subjected to alcohol precipitation and washing with 400ml of absolute ethanol, and the product was dried in a vacuum oven at 50 ℃ for 48 hours to obtain 6.9276g of a terpolymer PIA-SAS-AM with a yield of 86.60%.

Example 5 characterization of the results of the terpolymer PIA-SAS-AM

Infrared spectroscopic testing of the terpolymer PIA-SAS-AM synthesized in example 2 was carried outAs shown in figure 1, the terpolymer PIA-SAS-AM contains characteristic peaks as follows: 3438cm^-1The broad peak at (A) is due to-NH stretching of the amide group and-OH stretching of the carboxyl group, 1726cm^-1The absorption peak at (A) is the absorption peak of carboxyl and amide groups, 1448cm^-1And 1197cm^-1The peaks at (A) are due to C-N stretching and S ═ O asymmetric stretching, which can prove that the terpolymer PIA-SAS-AM has been successfully prepared.

The three raw materials used, itaconic acid, sodium allylsulfonate and acrylamide, and the terpolymer PIA-SAS-AM synthesized in example 2 were subjected to nuclear magnetic resonance hydrogen spectroscopy, and as shown in FIG. 2, itaconic acid has characteristic peaks at 3.30ppm, 5.77ppm and 6.25 ppm. As shown in FIG. 3, sodium allylsulfonate has characteristic peaks at 3.56ppm, 5.28ppm, and 5.82 ppm. As shown in FIG. 4, acrylamide has characteristic peaks at 5.71ppm and 6.12 ppm. As shown in FIG. 5, the hydrogen nuclear magnetic resonance spectrum of the terpolymer PIA-SAS-AM synthesized in example 2 has no characteristic peaks of itaconic acid, sodium allylsulfonate and acrylamide as raw materials, and all the characteristic peaks of the terpolymer PIA-SAS-AM are between 1ppm and 3ppm, which proves that the terpolymer PIA-SAS-AM is successfully prepared.

Gel permeation chromatography analysis of the terpolymer PIA-SAS-AM synthesized in example 1, as shown in fig. 7, the terpolymer PIA-SAS-AM has a weight average molecular weight of 2392, a number average molecular weight of 2056, a weight average molecular weight/number average molecular weight of 1.16, less than 2, a narrow molecular weight distribution, and meets the optimal range of inhibitor molecular weights: 10³-10⁵。

Example 6 thermal stabilization of terpolymer PIA-SAS-AM

By thermogravimetric analysis and spectrum analysis of the terpolymer PIA-SAS-AM synthesized in the embodiment 2, as shown in fig. 6, even at the temperature of more than 600 ℃, the polymer still has about 40% of mass residues, and the prepared terpolymer PIA-SAS-AM has good thermal stability.

Example 7 Water solubility testing of terpolymer PIA-SAS-AM

1g of the terpolymer PIA-SAS-AM synthesized in example 2 and 99mL of distilled water were added to a 250mL beaker, stirred at room temperature for 5 minutes at a stirring speed of 300rpm, and then the beaker was left to stand for 10 minutes, and the solution in the beaker was observed under natural light. As shown in FIG. 8, the solution in the beaker is clear and transparent, and has no suspended crystal particles, which indicates that the synthesized terpolymer PIA-SAS-AM has good water solubility.

Example 8 Crystal form and morphology characterization of terpolymer PIA-SAS-AM Performance evaluation product

The crystal form of the performance evaluation product of the terpolymer PIA-SAS-AM synthesized in example 2 is characterized by X-ray diffraction, as shown in FIG. 9, the diffraction peaks of the sample, namely the diffraction peaks corresponding to the (020), (021), (040) and (041) crystal faces of calcium sulfate dihydrate, are observed at 2 theta of 11.6, 21.84, 24.46 and 29.76 when the terpolymer PIA-SAS-AM with different concentrations is added, and the crystal form of the calcium sulfate dihydrate is proved to be not changed by the terpolymer PIA-SAS-AM.

The morphology of the product of the evaluation of the performance of the terpolymer PIA-SAS-AM synthesized in example 2 was characterized by a scanning electron microscope, as shown in FIG. 10, the terpolymer PIA-SAS-AM was not added, i.e., (a)0mg/L, and the crystal was a regular flaky and rod-like crystal with a smooth surface. With the addition of the terpolymer PIA-SAS-AM, namely (b)4mg/L, the crystal loses the originally smooth surface morphology and lattice defects begin to appear. Continuously increasing the concentration of the terpolymer PIA-SAS-AM, namely (c)8 mg/L; (d)12mg/L, lattice defects become more pronounced. Therefore, the addition of the terpolymer PIA-SAS-AM enables calcium sulfate dihydrate crystals to have defects, so that calcium sulfate scale is easy to remove.

Example 9 comparison of the calcium sulfate inhibition ratio of the terpolymer PIA-SAS-AM with that of the conventional polymer PAA (polyacrylic acid)

The calcium sulfate scale inhibition performance of the terpolymer PIA-SAS-AM synthesized in the example 2 and the calcium sulfate scale inhibition performance of the common polymer PAA are compared by adopting a static scale inhibition evaluation method under the same polymer concentration.

The calculation formula of the inhibition efficiency of the scale inhibitor is as follows:

in the formula c₂Calcium ion concentration (mg/L) after static evaluation of the addition of Scale inhibitor

c₀Calcium ion concentration (mg/L) after static evaluation without addition of scale inhibitor

c₁Initial calcium ion concentration (mg/L)

Static Scale inhibition evaluation initially contained 11100mg/L calcium chloride, 10660mg/L sodium sulfate and 15000mg/L sodium chloride.

As shown in FIG. 11, it can be seen that precipitated calcium sulfate scale is generated in the solution added with the polymer PAA, while the solution added with the terpolymer PIA-SAS-AM is clear and transparent and has no precipitated calcium sulfate scale, which indicates that the calcium sulfate scale inhibition performance of the terpolymer PIA-SAS-AM synthesized in example 2 is better than that of the common polymer PAA.

As can be seen from FIG. 12, under the same addition concentration, the calcium sulfate scale inhibition effect of the terpolymer PIA-SAS-AM is obviously higher than that of the polymer PAA, especially the calcium sulfate scale inhibition rate of the terpolymer PIA-SAS-AM is highest at 16mg/L, which can reach 99.51%, at this time, the calcium sulfate scale inhibition efficiency of the PAA is 46.87%, and the calcium sulfate scale inhibition rate of the terpolymer PIA-SAS-AM is much higher than that of the common polymer PAA.

Claims

1. A method for synthesizing a terpolymer type scale inhibitor is characterized by comprising the following steps:

(1) fully stirring itaconic acid, sodium allylsulfonate, acrylamide, a molecular regulator and water at room temperature to obtain a mixed solution, wherein the mass ratio of the itaconic acid to the sodium allylsulfonate to the acrylamide is (1-2): 1-2: 1-2, wherein the molecular regulator is one or two of isopropanol and isopropyl mercaptan, and the mass of the molecular regulator is 2-10 wt% of the total mass of itaconic acid, sodium allylsulfonate and acrylamide;

(2) preparing an initiator solution, and transferring the initiator solution to a constant-pressure dropping funnel, wherein the initiator is one or two of ammonium persulfate and potassium persulfate, and the mass of the initiator is 4-12 wt% of the total mass of itaconic acid, sodium allylsulfonate and acrylamide;

(3) vacuumizing the mixed solution obtained in the step (1), and introducing inert gas for protection to obtain the treated mixed solution, wherein the inert gas is nitrogen or argon;

(4) slowly dripping an initiator solution in the constant-pressure dropping funnel in the step (2) into the mixed solution treated in the step (3), and reacting at a high temperature to obtain a polymer solution, wherein the dripping time of the initiator solution is 1-1.5 h, the high-temperature reaction time is 0.5-4.5 h, and the high-temperature reaction temperature is 50-100 ℃;

(6) and (3) drying the precipitation product in a vacuum drying oven to obtain powdery polyitaconic acid-sodium allylsulfonate-acrylamide, namely the terpolymer scale inhibitor.

2. The method for synthesizing the terpolymer type scale inhibitor according to claim 1, wherein in the step (5), the volume ratio of the absolute ethyl alcohol to the polymer solution is 1: 4.

3. the method for synthesizing the terpolymer-type scale inhibitor according to claim 1, wherein in the step (6), the vacuum drying temperature is 50 ℃ and the drying time is 48 hours.

4. The terpolymer type scale inhibitor prepared by the synthesis method of any one of claims 1-3.

5. Use of the terpolymer scale inhibitor of claim 4 to inhibit or remove calcium sulfate scale.