CN-121975112-A - Polyaspartic quaternary ammonium salt for scale and corrosion inhibition, and preparation method and application thereof

Abstract

The invention discloses a polyaspartic acid quaternary ammonium salt for scale and corrosion inhibition, a preparation method and application thereof, belonging to the technical field of industrial circulating water treatment, the invention adopts a graft copolymerization method to introduce N, N-dimethyl ethylenediamine into the peptide chain of polyaspartic acid, and then the intermediate is quaternized by bromoacetic acid to synthesize a target compound, namely polyaspartic acid quaternary ammonium salt, which can be combined with metal ions such as Ca 2+ to generate a water-soluble complex compound with certain scale inhibition and corrosion inhibition performances. Therefore, the polyaspartic acid quaternary ammonium salt obviously improves the scale inhibition and corrosion inhibition performances, avoids the application of the phosphorus-containing compound, and effectively reduces the negative influence on the environment.

Inventors

• WANG YUXIA
• LI YANAN
• ZHANG RUNYI
• CAI SHUJING
• LIU JIAYIN

Assignees

• 河南大学

Dates

Publication Date

20260505

Application Date

20260203

Claims (9)

1. 1. The preparation method of the polyaspartic acid-based quaternary ammonium salt for scale and corrosion inhibition is characterized by comprising the following steps of: (1) Ring opening amidation, namely dissolving N, N-dimethyl ethylenediamine and polysuccinimide in water, heating and stirring at 45-50 ℃ to react completely, dialyzing, and evaporating the solvent to obtain a polyaspartic acid derivative intermediate with a side chain containing tertiary amine; (2) And quaternizing, namely dissolving the intermediate of the polyaspartic acid derivative in water, adding aqueous solution of bromoacetic acid and sodium hydroxide, stirring and reacting at 100-110 ℃, adjusting the pH value of the reaction solution to be alkalescent by using sodium bicarbonate solution in the reaction process, dialyzing after the reaction is completed, and evaporating the solvent to obtain the polyaspartic acid quaternary ammonium salt.
2. 2. The method for preparing polyaspartic acid quaternary ammonium salt for scale and corrosion inhibition according to claim 1, wherein in the step (1), the molar ratio of N, N-dimethyl ethylenediamine to the monomers in the polysuccinamide is (6-8): 1, and in the step (2), the molar ratio of polyaspartic acid derivative intermediate, bromoacetic acid and sodium hydroxide is (3-5): 1 (3-5).
3. 3. The method for preparing polyaspartic acid quaternary ammonium salt for scale and corrosion inhibition according to claim 1, wherein in the step (2), the concentration of sodium bicarbonate solution is 0.5-2 mol/L.
4. 4. The method for preparing polyaspartic acid quaternary ammonium salt for scale and corrosion inhibition according to claim 1, wherein the dialysis in the step (1) and/or the step (2) is performed in deionized water by using a dialysis bag with a molecular weight cut-off of 500-3000 Da until the conductivity of the deionized water is 1.5-2.5 mu S/cm.
5. 5. The method for preparing polyaspartic acid quaternary ammonium salt for scale and corrosion inhibition according to claim 1, wherein the weak alkalinity is pH value of 8-9.
6. 6. Polyaspartic quaternary ammonium salt for scale and corrosion inhibition prepared by the preparation method according to any one of claims 1 to 5.
7. 7. Use of the polyaspartic acid-based quaternary ammonium salt according to claim 6 as a water treatment agent for inhibiting scale formation and/or for slowing down metal corrosion in water systems.
8. 8. The use of the polyaspartic acid-based quaternary ammonium salt according to claim 6 as a scale inhibitor for inhibiting calcium phosphate scale and/or calcium sulfate scale.
9. 9. The use of polyaspartic acid-based quaternary ammonium salt according to claim 6 as corrosion inhibitor in the corrosion protection of carbon steel.

Description

Polyaspartic quaternary ammonium salt for scale and corrosion inhibition, and preparation method and application thereof Technical Field The invention belongs to the technical field of industrial circulating water treatment, and particularly relates to polyaspartic quaternary ammonium salt for scale and corrosion inhibition, and a preparation method and application thereof. Background Industrial circulating cooling water is widely applied to industries such as thermal power generation, steel, chemical industry, oil refining and the like, and is an indispensable medium in industrial production. However, during the operation of the circulating cooling water system, problems such as scaling, metal pipeline corrosion, microorganism breeding and the like are commonly existed, and the system efficiency and the equipment life are seriously affected. At present, physical methods and chemical methods are mainly adopted for treatment. The chemical method has the advantages of simple operation, low cost and the like, and has become the most widely applied water treatment technology. Among various chemical water treatment agents, polyaspartic Acid (PASP) has been attracting attention in recent years as an environmentally friendly polymer compound. PASP has good biodegradability and low ecological toxicity, can inhibit the scale formation of polyvalent metal ions such as calcium, magnesium, copper, iron and the like through chelation, and can form a protective film on the surface of metal, thereby having the functions of scale inhibition and corrosion inhibition. However, the traditional PASP has a relatively simple molecular structure and single functional group, and the comprehensive performance of the traditional PASP is still difficult to meet the increasingly complex industrial water treatment requirements. Therefore, structural modification of PASP to improve scale and corrosion inhibition efficiency thereof has become an important research direction in this field. At present, the main strategy of PASP modification is to introduce functional groups into the side chains of PASP to enrich the molecular structure and action mechanism of PASP. The quaternary ammonium salt group has good application potential in scale inhibition and corrosion inhibition due to the unique structure and performance. On one hand, the quaternary ammonium salt can be adsorbed on the surfaces of crystals such as calcium carbonate and calcium sulfate to interfere the normal growth of the crystals and induce lattice distortion so as to inhibit scale deposition, and on the other hand, positive charges in molecules of the quaternary ammonium salt can generate electrostatic action with anions (such as carbonate, sulfate radical and the like) in water to prevent the combination of scale forming ions. In addition, the hydrophobic chain segment in the quaternary ammonium salt structure and positively charged nitrogen atoms cooperate to promote the adsorption of the quaternary ammonium salt on the metal surface to form a compact protective film, so that corrosion medium is effectively isolated, and the electrochemical corrosion process is slowed down. Based on the mechanism, the invention innovatively introduces the quaternary ammonium salt group into the polyaspartic acid molecular structure, develops a novel polyaspartic acid quaternary ammonium salt through reasonable molecular design and synthesis path, aims at realizing the cooperative promotion of scale inhibition and corrosion inhibition performance, and provides a high-efficiency and environment-friendly multifunctional water treatment agent for an industrial circulating water system. Disclosure of Invention Aiming at the problems of single structure and limited scale and corrosion inhibition performance of Polyaspartic Acid (PASP) in the prior art, the invention aims to provide polyaspartic acid-based quaternary ammonium salt with novel structure and excellent performance for scale and corrosion inhibition, and a preparation method and application thereof. The product obviously improves the scale and corrosion inhibition efficiency by introducing the quaternary ammonium salt group into the PASP side chain, and provides a high-efficiency and environment-friendly multifunctional additive for industrial water treatment. In order to achieve the above purpose, the invention adopts the following technical scheme: In a first aspect, the invention provides a preparation method of polyaspartic quaternary ammonium salt for scale and corrosion inhibition, which comprises the following two steps of reaction: Firstly, performing ring-opening polymerization reaction on Polysuccinimide (PSI) by using N, N-dimethylethylenediamine (DMEDA), and introducing a structural unit containing tertiary amine groups into a polymer skeleton to prepare an intermediate, namely N, N-dimethylethylenediamine modified polyaspartic acid (PASP-DMEDA for short); then, the intermediate is subjected to quaternization reaction with