Ternary inhibition composition of sulfolane extraction agent and preparation method of ternary inhibition composition

Abstract

The invention belongs to the field of petrochemical engineering extraction separation, and provides a sulfolane-based extraction agent ternary inhibition composition and a preparation method thereof. According to the invention, a ternary synergistic inhibition design of compounding 10-200ppm of B1 derived polymer micelle intermediate I dispersoid, 20-200ppm of aromatic amine component and 50-200ppm of benzotriazole component on the basis of a sulfolane extraction agent is adopted, and through the synergistic effect of selective enrichment of polymer micelles on the metal surface, acid catching of aromatic amine and passivation of benzotriazole, the metal surface corrosion resistance of the metal surface is improved, and the metal surface corrosion resistance of the metal surface is improved. The performance that the corrosion rate of carbon steel is reduced by not less than 70% and the acid value is not higher than 0.01 mgKOH / g during long-term operation under the ppm-level extremely low addition amount is achieved, the contradiction between the strong dissolving capacity of a high-polarity extraction agent and low-corrosivity long-term protection is solved, the problem of balance of extremely-low-solid-content microstructure stability and long-period acidification resistance is solved, and the extraction efficiency is improved. The method has wide application value in industrial extraction processes such as aromatic hydrocarbon extraction, lubricating oil refining and acid gas removal.

Description

Technical Field

[0001] This invention relates to the field of petrochemical extraction and separation technology, specifically to a ternary inhibitory composition of sulfolane-based extractant and its preparation method. Background Technology

[0002] Sulfolane, a highly polar aprotic solvent, is widely used in extraction and separation processes in the oil refining industry, such as aromatic hydrocarbon extraction, lubricating oil refining, and acid gas removal, due to its excellent selective solubility for aromatic hydrocarbons and olefins, high boiling point, low volatility, and good thermal stability. In aromatic hydrocarbon extraction units, sulfolane extractant needs to maintain stable performance under harsh conditions of high temperature (150-220℃), high circulating load (hundreds to thousands of tons / hour), and long-term operation (6-12 months or longer). This places extremely high demands on the extractant's antioxidant capacity, degradation resistance, and low corrosiveness. Under high-temperature conditions, sulfolane undergoes hydrolysis and oxidation, generating acidic degradation products such as butyrolactone, succinic acid, and sulfonic acid. The accumulation of these acidic substances not only leads to an increase in the extractant's acid value and deterioration of extraction performance, but more importantly, it causes severe corrosion to carbon steel extraction towers, pipelines, heat exchangers, and other equipment, resulting in equipment perforation, leaks, and even unplanned shutdowns, seriously affecting the long-term safe and stable operation and economic benefits of the unit. Therefore, developing sulfolane extractant protection technology that can effectively inhibit the formation of acidic degradation products, significantly reduce the corrosion rate of metal equipment, and ensure long-term operational stability without significantly altering the physical properties and mass transfer performance of the extractant is of great significance for improving the economy and reliability of industrial processes such as aromatic hydrocarbon extraction.

[0003] For corrosion protection of sulfolane extractants, current industrial methods mainly involve adding organic amine acid scavengers and benzotriazole metal passivators, but these methods have significant shortcomings. Traditional inhibitors require high dosages (500-2000 ppm) to achieve ideal protective effects, leading to significant changes in the extractant's viscosity, density, and other physical properties, affecting the mass transfer efficiency and separation performance of the extraction tower. Single inhibitors or simple compound systems suffer from rapid consumption and poor protective durability during long-term operation. For example, Chinese patent CN 102732221 A discloses a sulfolane extractant corrosion inhibitor formulation using a combination of aromatic amines and benzotriazoles, but this requires a high total dosage (800-1500 ppm), and the inhibitor is consumed rapidly during high-temperature, long-term operation, necessitating frequent replenishment. Chinese patent CN 107083271 A discloses a sulfolane corrosion inhibitor containing imidazoline derivatives. Although the long-chain alkyl structure of imidazoline is introduced to enhance interfacial adsorption, the corrosion inhibitor is an oil-soluble small molecule. In highly polar sulfolane media, it has problems such as excessively high solubility, insufficient interfacial enrichment ability, and difficulty in forming a stable protective film, resulting in limited protective effect and poor stability. Summary of the Invention

[0004] The purpose of this invention is to provide a ternary inhibitory composition of sulfolane-based extractant and its preparation method, which solves the fundamental contradiction between high polarity and high solubility and low corrosivity and long-term protection in the current sulfolane extraction system, the balance between the stability of highly diluted microstructure and long-term acid resistance, and the essential conflict between the stability of solvent property window and strong interfacial adsorption protection performance.

[0005] This invention achieves synergistic effects of three components in a highly polar medium of sulfolane by innovatively designing a ppm-level ternary synergistic compound of nano-scale B1-derived polymer microparticles, aromatic amine acid scavengers, and benzotriazole passivators: the polymer microparticles selectively enrich and physically shield at the metal / solvent interface through their amphiphilic structure; the aromatic amine component inhibits acid corrosion by capturing acidic degradation products; and the benzotriazole component forms a dense passivation film by complexing with the metal surface to block electrochemical corrosion. Under the synergistic effect of the three components, a significant effect of reducing the corrosion rate of carbon steel by no less than 70% is achieved with an extremely low total addition amount (80-600 ppm), while maintaining the stability of the extractant's physical properties and the low acid value characteristics of long-term operation, demonstrating the synergistic effect mechanism of multi-component synergistic protection across scales.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A ternary inhibitory composition based on sulfolane extractant A1, wherein the amounts of each component are based on the mass of sulfolane extractant A1, and the composition comprises: sulfolane extractant A1, which includes 95-99.0 wt% sulfolane, 1.0-5.0 wt% water, and 0-1.0 wt% azeotropic aromatic hydrocarbon, wherein the sum of the mass fractions of the components is 100 wt%; dispersed in sulfolane extractant A1. The sulfone-based extractant A1 contains a B1-derived polymer microparticle intermediate I dispersion with a dry polymer solids content of 10–200 ppm, wherein B1 represents a structural unit derived from heptadecenylhydroxyethylimidazoline, and the B1-derived polymer microparticle intermediate I dispersion is an oil-in-water polymer microparticle dispersion; an aromatic amine component B2 in an amount of 20–200 ppm; a benzotriazole component B3 in an amount of 50–200 ppm; and optional adjuvants in an amount of 0–50 ppm.

[0008] Furthermore, the polymer dry basis of the B1-derived polymer microparticle intermediate I dispersion is composed of the following structural units: 30–70 mol% of B1 structural units, which are derived from heptadecanylhydroxyethylimidazoline; 5–30 mol% of benzotriazole structural units C1, which are derived from benzotriazole compounds; 5–30 mol% of crosslinking structural units, which are derived from at least one difunctional or polyfunctional crosslinking agent; and 0–20 mol% of flexible segment structural units, wherein the sum of the molar fractions of the above structural units is 100 mol%; wherein the median volumetric particle size D50 of the polymer microparticles in the B1-derived polymer microparticle intermediate I dispersion is 80–200 nm; and the acid neutralization equivalent of the B1-derived polymer microparticle intermediate I dispersion is not less than 2.0 mmol KOH / g based on the polymer dry basis.

[0009] Further, the B1-derived polymer microparticle intermediate I dispersion was prepared by the following steps: Preparation of the aqueous phase: 100 parts by mass of heptadecanylhydroxyethylimidazoline and 10-40 parts by mass of benzotriazole compounds were added to deionized water. After stirring and dissolving, the pH of the aqueous phase was adjusted to 7.0-9.5 using sodium hydroxide solution, controlling the total mass fraction of heptadecanylhydroxyethylimidazoline and benzotriazole compounds to be 5-30 wt%, thus obtaining the aqueous phase; Preparation of the organic continuous phase: 5-50 parts by mass of the nonionic surfactant Triton X-100 (based on 100 parts by mass of heptadecanylhydroxyethylimidazoline in step A1) were added to an organic phase containing 300-800 parts by mass of sulfolane and 0-200 parts by mass of n-heptane (based on 100 parts by mass of heptadecanylhydroxyethylimidazoline in step A1), and the mixture was stirred until homogeneous to obtain the organic continuous phase; The mixture was then heated at a temperature of 2... An organic continuous phase is stirred at 0–40°C, and an aqueous phase is added to the organic continuous phase at a basically constant flow rate over 0.5–3.0 h to form a stable emulsion. Under an inert atmosphere, the emulsion is heated to 40–80°C, and a crosslinking agent is added to the emulsion over 0.5–2.0 h. The total amount of the crosslinking agent added is 5–30 mol% relative to the molar number of the B1 structural unit. The crosslinking agent is selected from one or more of 1,4-butanediol diglycidyl ether, p-dichloromethylbenzene, and hexamethylene diisocyanate. The reaction system is cooled to 25–40°C, and some n-heptane and water are removed from the system under reduced pressure. Excess aqueous phase is removed by phase separation, and sulfolane is added to adjust the solid content of the dispersion to 20–40 wt%. Large particles with a particle size greater than 1 μm are removed by filtration, and the mixture is filled under nitrogen protection to obtain B1-derived polymer microparticle intermediate I dispersion.

[0010] Furthermore, when the sulfolane extractant A1 contains an azeotropic aromatic hydrocarbon, the azeotropic aromatic hydrocarbon is selected from one or more of benzene, toluene, and xylene isomers; the aromatic amine component B2 is an aromatic amine acid scavenger, selected from one or two of diphenylamine and N-phenyl-1-naphthylamine; the benzotriazole component B3 is a metal passivator, selected from one or more of benzotriazole, toluenetriazole, and their soluble salts; and the adjuvant is selected from one or more of defoamers, flow improvers, and dispersion stabilizers.

[0011] Furthermore, the flexible segmental structural units are derived from one or more of hydrophilic or hydrophobic diols, diamines, or polyethers.

[0012] Furthermore, the flexible segmental structural units are derived from one or more of polyethylene glycol 400, neopentyl glycol, and 1,6-hexanediol.

[0013] Furthermore, after continuous operation of the ternary inhibitory composition of sulfolane extractant in an industrial plant for 6 to 12 months, the acid value of the sulfolane extractant ternary inhibitory composition is not higher than 0.01 mg KOH / g.

[0014] As a concept of this invention, the ternary synergistic design of B1-derived polymer microparticle intermediate I dispersion, aromatic amine component B2, and benzotriazole component B3 is mainly used to enhance the corrosion resistance and long-term operational stability of sulfolane extractant. The B1-derived polymer microparticles, by introducing heptadecanyl hydroxyethyl imidazoline long-chain structural units, benzotriazole functional structural units, and cross-linked network structures into the nanoscale microparticle system, achieve stable colloidal dispersion in the highly polar medium of sulfolane and selective enrichment at the metal interface. The long-chain alkyl imidazoline structure provides hydrophobic anchoring, promoting the migration and adsorption of microparticles to the metal surface. The cross-linked network structure endows the microparticles with structural stability and anti-swelling properties at high temperatures. The benzotriazole functional groups embedded in the polymer backbone achieve long-term sustained-release passivation, thereby constructing a dual protective layer on the metal surface that combines physical shielding and chemical passivation. Aromatic amine component B2 acts as an acid scavenger, neutralizing acidic substances such as succinic acid and sulfonic acid produced by the high-temperature degradation of sulfolane through its basic amino group. This effectively reduces the acid value of the system and blocks the corrosive effect of acidic media on the metal. Simultaneously, the conjugated structure of the aromatic amine possesses certain antioxidant properties, which can delay the oxidative degradation process of the extractant. Benzotriazole component B3 acts as a metal passivator, forming coordinate bonds between the lone pair electrons in its nitrogen heterocyclic structure and iron atoms on the carbon steel surface through its nitrogen heterocyclic structure. This generates a dense organic-inorganic composite passivation film on the metal surface, which blocks the contact between the corrosive medium and the metal substrate, significantly reducing the electrochemical corrosion rate. The synergistic effect of the three components is reflected in the following aspects: the enrichment of polymer microparticles at the interface provides a high-concentration reaction microenvironment for aromatic amines and benzotriazole, enhancing the local efficiency of acid capture and passivation; the aromatic amine reduces the acid corrosion damage to polymer microparticles and passivation film by lowering the acid value of the system, thus extending the effective life of the protective layer; the passivation effect of benzotriazole and the physical shielding of polymer microparticles form a double layer of protection, synergistically reducing the corrosion rate, thereby achieving a highly efficient, durable and stable protective effect that is difficult to achieve with a single component or simple compound system at an extremely low total addition amount in ppm.

[0015] This invention also discloses a method for preparing a ternary inhibitory composition of sulfolane extractant, comprising the following steps: preparing a dispersion of B1-derived polymer microparticle intermediate I with a solid content of 20-40 wt%; placing 100 parts by mass of sulfolane extractant A1 in a solvent tank equipped with a stirring device at a temperature of 30-50°C, adding a metered amount of B1-derived polymer microparticle intermediate I dispersion, and adjusting the concentration of polymer dry basis solids to 10-200 ppm based on sulfolane extractant A1, and stirring for 30-120 min to allow the B1-derived polymer microparticle intermediate I dispersion to be absorbed by the sulfolane extractant. The sulfolane extractant is uniformly dispersed in agent A1. Aromatic amine component B2 and benzotriazole component B3 are added to the system obtained in step S2 using a metering pump. Based on sulfolane extractant A1, the dosage of aromatic amine component B2 is 20–200 ppm, and the dosage of benzotriazole component B3 is 50–200 ppm. The mixture is stirred for 30–60 min at a temperature of 30–50°C to obtain a homogeneous sulfolane extractant ternary inhibitory composition. The density, viscosity, and conductivity of the sulfolane extractant ternary inhibitory composition obtained in step S2 are measured. Once these physical properties stabilize, the sulfolane extractant ternary inhibitory composition is obtained.

[0016] In this invention, the B1-derived polymer microparticle intermediate I dispersion, aromatic amine component B2, and benzotriazole component B3 exhibit significant multi-level synergistic effects. The B1-derived polymer microparticles primarily focus on constructing a physical shielding layer at the metal / solvent interface and providing durable chemical passivation. Their nanoscale size and amphiphilic structure achieve stable dispersion and interfacial selective enrichment in highly polar media containing sulfolane. The long-chain alkyl imidazoline structure provides hydrophobic anchoring and interfacial adsorption driving force, while the cross-linked network structure imparts high-temperature structural stability. The built-in benzotriazole functional groups achieve long-term sustained release of the passivation function. Aromatic amine component B2 primarily focuses on capturing acidic degradation products in the system. It neutralizes acidic substances such as succinic acid and sulfonic acid through basic amino groups, reducing the system's acid value and blocking the corrosive damage of the acidic medium to the metal and polymer protective layer. Its conjugated structure's antioxidant properties delay the oxidative degradation of the extractant. Benzotriazole component B3 primarily focuses on rapidly forming a dense coordination passivation film on the metal surface. This film uses the coordination bonding of lone pairs of electrons from nitrogen heterocycles with iron atoms to block contact between the corrosive medium and the metal substrate. The synergistic mechanism of these three components manifests at both the microscopic and macroscopic levels: At the microscopic level, the enrichment of polymer microparticles at the interface creates a high-concentration reaction microenvironment for aromatic amines and benzotriazoles, enhancing local acid capture efficiency and the passivation film growth rate; the aromatic amines reduce acid corrosion damage to the cross-linked structure of the polymer microparticles and the benzotriazole passivation film by lowering the system's acid value, thus extending the effective lifespan of the protective layer; the rapid passivation of benzotriazoles and the persistent shielding of the polymer microparticles form a dual protection in both time and space. At the macroscopic performance level, the synergistic effect of these three components allows for a significant reduction in corrosion rate of no less than 70% with an extremely low total addition amount at the ppm level, far exceeding the protective capabilities of single-component or simple two-component compound systems, fully demonstrating the synergistic effect mechanism of multi-component cross-scale synergy.

[0017] Beneficial technical effects

[0018] 1. Significantly reduced corrosion rate and long-term stable operation: This invention utilizes a ppm-level ternary synergistic compound design of B1-derived polymer microparticles, aromatic amine acid scavengers, and benzotriazole passivators. Under simulated operating conditions, the corrosion rate of carbon steel is no higher than 0.02 mm per year. Compared with the control system containing only sulfolane-based extractant A1, the corrosion rate is reduced by no less than 70%. Furthermore, after continuous operation in industrial equipment for 6-12 months, the acid value is no higher than 0.01 mg KOH / g. This effectively inhibits the generation and accumulation of acidic degradation products at the source, extending the service life of the extraction equipment and ensuring the long-term safe and stable operation of the device.

[0019] 2. Maintaining excellent process properties of the extractant at extremely low addition levels: This invention utilizes high dispersion technology of nano-sized polymer microparticles and precise multi-component ratio at the ppm level to achieve excellent protective effects with a total addition of only 80-600 ppm. Compared with traditional inhibitor systems (500-2000 ppm), this reduces the dosage by 40-70%. At such low addition levels, the key process properties of the extractant, such as density, viscosity, and conductivity, remain largely unaffected, ensuring that the mass transfer efficiency, separation performance, and hydrodynamic characteristics of the extraction tower remain stable, thus balancing corrosion protection performance with extraction process requirements.

[0020] 3. Constructing a multi-layered synergistic protection mechanism to enhance protection durability: This invention introduces heptadecanyl hydroxyethyl imidazoline long-chain structural units, benzotriazole functional structural units, and cross-linked network structures into a nanoscale microparticle system. Combined with the synergistic effect of free aromatic amine acid scavengers and benzotriazole passivators, a triple protection system of "polymer microparticle physical shielding layer + passivation film chemical protection layer + acid value control of acid scavengers" is constructed on the metal surface. The cross-linked structure of the polymer microparticles ensures structural stability and anti-swelling properties at high temperatures, the built-in benzotriazole functional groups achieve long-term sustained release of passivation function, and the aromatic amine maintains a low acid value environment by continuously neutralizing acidic degradation products. The synergistic effect of the three in the time and space dimensions significantly improves the durability and reliability of the protection system.

[0021] 4. Achieving stable dispersion and interfacial enrichment of nanomaterials in highly polar media: This invention constructs core-shell polymer microparticles with an amphiphilic shell and a crosslinking core in situ in sulfolane media using reverse emulsion polymerization technology. The median particle size (D50) is controlled within the range of 80-200 nm. Combined with the dispersing and stabilizing effect of 5-50 ppm nonionic surfactant Triton X-100, long-term colloidal stability and uniform dispersion of nanomaterials in highly polar sulfolane media are achieved. At the same time, the hydrophobic anchoring effect of the heptadecenyl long-chain alkyl imidazoline structure promotes the selective migration and adsorption of microparticles to the metal / solvent interface, solving the problem of balancing microstructure stability and interfacial enrichment capacity under highly diluted conditions.

[0022] 5. Providing a controllable, efficient, and reproducible industrial preparation method: This invention employs a stepwise mixing process to first prepare a B1-derived polymer microparticle intermediate I dispersion with a solid content of 20-40 wt%. Then, through precise metering and temperature / stirring control, the microparticle dispersion, aromatic amine component, and benzotriazole component are sequentially added to a sulfolane-based extractant. The stability of physical properties such as density, viscosity, and conductivity is tested to determine whether the system has reached a homogeneous and stable state. This preparation method is simple to operate, has controllable parameters, and good reproducibility, making it suitable for large-scale industrial production and online addition applications. It provides an economical, efficient, and reliable technical solution for equipment protection in industrial extraction processes such as aromatic hydrocarbon extraction, lubricating oil refining, and acid gas removal. Attached Figure Description

[0023] Figure 1 XPS depth profile of Fe, N, O, and C element atomic fractions in Example 1.

[0024] Figure 2 XPS depth profile of Fe, N, O, and C atomic fractions in Comparative Example 1.

[0025] Figure 3 XPS depth profile of Fe, N, O, and C atomic fractions in Comparative Example 13.

[0026] Figure 4 Fitting diagrams of high-resolution photoelectron spectra of Fe 2p from Example 1 and Comparative Example 1.

[0027] Figure 5 Histograms of average N atom fraction at the interface (0–5 nm) for Examples 1, Comparative Example 1, and Comparative Example 13.

[0028] Figure 6 Nanoparticle size distribution in sulfolane extractant A1 for Examples 1, 9, and 10.

[0029] Figure 7 Dispersion stability evaluation graphs of the evolution of median particle size D50 over time during 720 h of storage for Examples 1–4 and Comparative Example 9.

[0030] Figure 8 Box plots of the statistical distribution of particle size growth rate after 720 h of storage for Examples 1–4 and Comparative Examples 1–13. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0032] Example 1

[0033] This embodiment provides a ternary inhibitory composition based on sulfolane extractant A1, wherein the amounts of each component are relative to the mass of sulfolane extractant A1. Sulfolane extractant A1 in this embodiment comprises: 97.0 wt% sulfolane, 3.0 wt% water, and 0 wt% azeotropic aromatic hydrocarbon, wherein the sum of the mass fractions of the components is 100 wt%. The composition of this embodiment also includes a B1-derived polymer microparticle intermediate I dispersion dispersed in the sulfolane extractant A1, with a polymer dry basis solids content of 100 ppm, wherein B1 represents a structural unit derived from heptadecanylhydroxyethylimidazolium, and the B1-derived polymer microparticle intermediate I dispersion is an oil-in-water polymer microparticle dispersion. The composition of this embodiment also includes an aromatic amine component B2 at 100 ppm, a benzotriazole component B3 at 120 ppm, and an adjuvant at 0 ppm.

[0034] The polymer dry basis of the B1-derived polymer microparticle intermediate I dispersion of this embodiment is composed of the following structural units: 50 mol% of B1 structural units derived from heptadecanylhydroxyethylimidazoline; 15 mol% of benzotriazole structural units C1 derived from benzotriazole compounds; 20 mol% of crosslinking structural units derived from 1,4-butanediol diglycidyl ether; and 15 mol% of flexible segment structural units derived from polyethylene glycol 400, wherein the sum of the molar fractions of the above structural units is 100 mol%. The median volumetric particle size (D50) of the polymer microparticles in the B1-derived polymer microparticle intermediate I dispersion of this embodiment is 140 nm, and the acid neutralization equivalent of the B1-derived polymer microparticle intermediate I dispersion of this embodiment is 2.5 mmol KOH / g on a polymer dry basis.

[0035] The B1-derived polymer microparticle intermediate I dispersion of this embodiment is prepared by the following steps: Step A1 is the preparation of the aqueous phase. 100 parts by mass of heptadecanylhydroxyethylimidazoline and 25 parts by mass of benzotriazole are added to deionized water. After stirring and dissolving, the pH of the aqueous phase is adjusted to 8.0 using sodium hydroxide solution, controlling the total mass fraction of heptadecanylhydroxyethylimidazoline and benzotriazole to be 17 wt%, thus obtaining the aqueous phase. Step A2 is the preparation of the organic continuous phase. 25 parts by mass of the nonionic surfactant Triton X-100 (based on 100 parts by mass of heptadecanylhydroxyethylimidazoline in step A1) are added to an organic phase containing 550 parts by mass of sulfolane and 100 parts by mass of n-heptane (based on 100 parts by mass of heptadecanylhydroxyethylimidazoline in step A1), and the mixture is stirred until homogeneous to obtain the organic continuous phase. Step A3 is the preparation of the organic continuous phase at a temperature of… The organic continuous phase of this embodiment is stirred at 30°C, and the aqueous phase of this embodiment is added to the organic continuous phase of this embodiment at a substantially constant flow rate over 1.5 hours to form a stable emulsion; Step A4 involves heating the emulsion of this embodiment to 60°C under an inert atmosphere, and adding the crosslinking agent 1,4-butanediol diglycidyl ether to the emulsion of this embodiment over 1.0 hour, with the total amount of the crosslinking agent added being 17.5 mol% relative to the molar number of the B1 structural unit; Step A5 involves cooling the reaction system to 32°C, removing some of the n-heptane and water from the system under reduced pressure, removing the excess aqueous phase through phase separation, adding sulfolane to adjust the solid content of the dispersion to 30 wt%, filtering to remove large particles with a particle size greater than 1 μm, and filling under nitrogen protection to obtain the B1-derived polymer microparticle intermediate I dispersion of this embodiment.

[0036] The sulfolane extractant A1 in this embodiment does not contain azeotropic aromatic hydrocarbons. The aromatic amine component B2 in this embodiment is the aromatic amine acid scavenger diphenylamine. The benzotriazole component B3 in this embodiment is the metal passivator benzotriazole. No additives were added in this embodiment. The flexible chain segment structural unit in this embodiment is derived from polyethylene glycol 400.

[0037] After 8 months of continuous operation in an industrial plant using the sulfolane-based extractant ternary inhibitor composition of this embodiment as the extractant, the acid value of the sulfolane-based extractant ternary inhibitor composition of this embodiment was 0.008 mg KOH / g. Under simulated operating conditions, the corrosion rate on carbon steel was 0.015 mm per year; compared with the control system using only sulfolane-based extractant A1 without the addition of B1 derivative polymer microparticle intermediate I dispersion, aromatic amine component B2, and benzotriazole component B3 under the same operating conditions, the corrosion rate was reduced by 75%.

[0038] The preparation method of the ternary inhibitory composition of the sulfolane extractant in this embodiment includes the following steps: Step S1 is to prepare a dispersion of B1-derived polymer microparticle intermediate I with a solid content of 30 wt%; Step S2 is to place 100 parts by mass of the sulfolane extractant A1 of this embodiment into a solvent tank equipped with a stirring device at a temperature of 40°C, add a metered amount of the B1-derived polymer microparticle intermediate I dispersion of this embodiment, and, based on the sulfolane extractant A1, make the concentration converted to polymer dry basis solids 100 ppm, and stir for 60 min to make the B1-derived polymer microparticle intermediate I dispersion of this embodiment conform to the sulfolane extractant of this embodiment. The mixture is uniformly dispersed in extractant A1; Step S3 involves adding aromatic amine component B2 and benzotriazole component B3 to the system obtained in step S2 using a metering pump. Based on sulfolane extractant A1, the dosage of aromatic amine component B2 is 100 ppm and the dosage of benzotriazole component B3 is 120 ppm. The mixture is stirred for 45 min at 40°C to obtain a homogeneous sulfolane extractant ternary inhibitory composition; Step S4 involves testing the density, viscosity, and conductivity of the sulfolane extractant ternary inhibitory composition obtained in step S3. Once the above physical properties are stable, the sulfolane extractant ternary inhibitory composition of this embodiment is obtained.

[0039] Features of this embodiment: This embodiment adopts a stable scheme with moderate parameter configuration. The sulfolane content is 97.0 wt%, the water content is 3.0 wt%, and the B1-derived polymer microparticle intermediate I dispersion contains 50 mol% B1 structural units, 15 mol% benzotriazole structural units (C1), 20 mol% crosslinking structural units, and 15 mol% flexible segment structural units in the polymer dry base. The median particle size (D50) of the polymer microparticles is 140 nm, and the acid neutralization equivalent is 2.5 mmol KOH / g. The composition contains B1-derived polymer microparticle intermediates... The dispersion I has a dry basis content of 100 ppm, the aromatic amine component B2 has a content of 100 ppm, and the benzotriazole component B3 has a content of 120 ppm. The preparation process uses moderate temperature and time parameters. The parameters of this scheme are selected in the middle range of each range (40-60%), which has good stability and reproducibility, can ensure long-term stable operation, reduce the corrosion rate by up to 75%, and control the acid value below 0.01 mg KOH / g. It is suitable for continuous chemical production plants with high requirements for process stability, and is particularly suitable for long-term stable operation of large-scale aromatic extraction plants.

[0040] Example 2

[0041] This embodiment provides a ternary inhibitory composition based on sulfolane extractant A1, wherein the amounts of each component are relative to the mass of sulfolane extractant A1. Sulfolane extractant A1 in this embodiment comprises: 96.5 wt% sulfolane, 3.0 wt% water, and 0.5 wt% azeotropic aromatic toluene, wherein the sum of the mass fractions of the components is 100 wt%. The composition of this embodiment also includes a B1-derived polymer microparticle intermediate I dispersion dispersed in the sulfolane extractant A1, with a polymer dry basis solids content of 160 ppm, wherein B1 represents a structural unit derived from heptadecanylhydroxyethylimidazoline, and the B1-derived polymer microparticle intermediate I dispersion is an oil-in-water polymer microparticle dispersion. The composition of this embodiment also includes an aromatic amine component B2 at 150 ppm, a benzotriazole component B3 at 180 ppm, and an adjuvant at 20 ppm.

[0042] The polymer dry basis of the B1-derived polymer microparticle intermediate I dispersion of this embodiment is composed of the following structural units: 60 mol% of B1 structural units derived from heptadecanylhydroxyethylimidazoline; 20 mol% of benzotriazole structural units C1 derived from benzotriazole compounds; 15 mol% of crosslinking structural units derived from p-dichloromethylbenzene; and 5 mol% of flexible segment structural units derived from neopentyl glycol, wherein the sum of the molar fractions of the above structural units is 100 mol%. The median volumetric particle size (D50) of the polymer microparticles in the B1-derived polymer microparticle intermediate I dispersion of this embodiment is 110 nm, and the acid neutralization equivalent of the B1-derived polymer microparticle intermediate I dispersion of this embodiment is 3.0 mmol KOH / g on a polymer dry basis.

[0043] The B1-derived polymer microparticle intermediate I dispersion of this embodiment is prepared by the following steps: Step A1 is the preparation of the aqueous phase, adding 100 parts by mass of heptadecanylhydroxyethylimidazoline and 35 parts by mass of toluenetriazole to deionized water, stirring to dissolve, and then adjusting the pH of the aqueous phase to 9.0 with sodium hydroxide solution, controlling the total mass fraction of heptadecanylhydroxyethylimidazoline and toluenetriazole to be 22 wt%, to obtain the aqueous phase; Step A2 is the preparation of the organic continuous phase, adding 400 parts by mass of sulfolane and 150 parts by mass of n-heptane (based on 100 parts by mass of heptadecanylhydroxyethylimidazoline in step A1) to the organic phase, and stirring until homogeneous to obtain the organic continuous phase; Step A3 is... The organic continuous phase of this embodiment is stirred at a temperature of 25°C. The aqueous phase of this embodiment is added to the organic continuous phase of this embodiment at a substantially constant flow rate over 2.5 hours to form a stable emulsion. Step A4 involves heating the emulsion of this embodiment to 50°C under an inert atmosphere and adding the crosslinking agent p-dichloromethylbenzene to the emulsion of this embodiment over 1.5 hours. The total amount of the crosslinking agent added is 12 mol relative to the molar number of the B1 structural unit. Step A5 involves cooling the reaction system to 28°C, removing some of the n-heptane and water from the system under reduced pressure, removing the excess aqueous phase through phase separation, adding sulfolane to adjust the solid content of the dispersion to 35 wt%, filtering to remove large particles with a particle size greater than 1 μm, and filling under nitrogen protection to obtain the B1-derived polymer microparticle intermediate I dispersion of this embodiment.

[0044] The sulfolane extractant A1 in this embodiment contains toluene as an azeotropic aromatic hydrocarbon. The aromatic amine component B2 in this embodiment is an aromatic amine acid scavenger, a mixture of diphenylamine and N-phenyl-1-naphthylamine in a 1:1 mass ratio. The benzotriazole component B3 in this embodiment is toluenetriazole, a metal passivating agent. The adjuvant in this embodiment is a dispersing stabilizer. The flexible segmental structural unit in this embodiment is derived from neopentyl glycol.

[0045] After 10 months of continuous operation in an industrial plant using the sulfolane-based extractant ternary inhibitor composition of this embodiment as the extractant, the acid value of the sulfolane-based extractant ternary inhibitor composition of this embodiment was 0.007 mg KOH / g. Under simulated operating conditions, the corrosion rate on carbon steel was 0.012 mm per year; compared with the control system using only sulfolane-based extractant A1 without the addition of B1 derivative polymer microparticle intermediate I dispersion, aromatic amine component B2, and benzotriazole component B3 under the same operating conditions, the corrosion rate was reduced by 80%.

[0046] The preparation method of the ternary inhibitory composition of the sulfolane extractant in this embodiment includes the following steps: Step S1 is to prepare a dispersion of B1-derived polymer microparticle intermediate I with a solid content of 35 wt%; Step S2 is to place 100 parts by mass of the sulfolane extractant A1 of this embodiment into a solvent tank equipped with a stirring device at a temperature of 35°C, add a metered amount of the B1-derived polymer microparticle intermediate I dispersion of this embodiment, and, based on the sulfolane extractant A1, make the concentration converted to polymer dry basis solids 160 ppm, and stir for 90 min to make the B1-derived polymer microparticle intermediate I dispersion of this embodiment conform to the sulfolane extractant of this embodiment. The extractant A1 is uniformly dispersed. Step S3 involves adding aromatic amine component B2 and benzotriazole component B3 to the system obtained in step S2 using a metering pump. Based on sulfolane extractant A1, the dosage of aromatic amine component B2 is 150 ppm, and the dosage of benzotriazole component B3 is 180 ppm. The mixture is stirred for 55 minutes at 35°C to obtain a homogeneous sulfolane extractant ternary inhibitory composition. Step S4 involves testing the density, viscosity, and conductivity of the sulfolane extractant ternary inhibitory composition obtained in step S3. Once these physical properties stabilize, the sulfolane extractant ternary inhibitory composition of this embodiment is obtained. In step S2, 30 ppm of the nonionic surfactant Triton X-100 is added as a dispersion stabilizer.

[0047] Features of this embodiment: This embodiment adopts a high inhibitor content scheme to enhance anti-corrosion performance. The sulfolane content is 96.5wt%, the water content is 3.0wt%, the azeotropic aromatic toluene content is 0.5wt%, and the B1-derived polymer microparticle intermediate I dispersion contains 60mol% B1 structural units, 20mol% benzotriazole structural units (C1), 15mol% crosslinking structural units, and 5mol% flexible segment structural units in the polymer dry basis. The median particle size (D50) of the polymer microparticles is 110nm (relatively small), and the acid neutralization equivalent is 3.0mmolKOH / g (relatively high). The dry basis content of B1-derived polymer microparticle intermediate I dispersion in the composition is... With a concentration of 160 ppm for aromatic amine component B2, 150 ppm for benzotriazole component B3 (all relatively high), and the addition of 20 ppm for dispersant stabilizer and 30 ppm for nonionic surfactant Triton X-100, this formulation enhances corrosion resistance through the synergistic effect of high B1 and benzotriazole structural units. The smaller particle size and higher acid neutralization equivalent improve dispersion stability and buffering capacity, reducing the corrosion rate by up to 80% and controlling the acid value at 0.007 mg KOH / g. It is suitable for highly corrosive working environments, and is particularly suitable for processing heavy aromatic raw materials with a high content of acidic impurities or extraction units operating under high temperature and high pressure conditions.

[0048] Example 3

[0049] This embodiment provides a ternary inhibitory composition based on sulfolane extractant A1, wherein the amounts of each component are relative to the mass of sulfolane extractant A1. Sulfolane extractant A1 in this embodiment comprises: 98.5 wt% sulfolane, 1.5 wt% water, and 0 wt% azeotropic aromatic hydrocarbon, wherein the sum of the mass fractions of the components is 100 wt%. The composition of this embodiment also includes a B1-derived polymer microparticle intermediate I dispersion dispersed in the sulfolane extractant A1, with a polymer dry basis solids content of 50 ppm, wherein B1 represents a structural unit derived from heptadecanylhydroxyethylimidazolium, and the B1-derived polymer microparticle intermediate I dispersion is an oil-in-water polymer microparticle dispersion. The composition of this embodiment also includes an aromatic amine component B2 at 60 ppm, a benzotriazole component B3 at 80 ppm, and an adjuvant at 10 ppm.

[0050] The polymer dry basis of the B1-derived polymer microparticle intermediate I dispersion of this embodiment is composed of the following structural units: 40 mol% of B1 structural units derived from heptadecanylhydroxyethylimidazoline; 10 mol% of benzotriazole structural units C1 derived from benzotriazole compounds; 30 mol% of crosslinking structural units derived from hexamethylene diisocyanate; and 20 mol% of flexible segment structural units derived from 1,6-hexanediol, wherein the sum of the molar fractions of the above structural units is 100 mol%. The median volumetric particle size (D50) of the polymer microparticles in the B1-derived polymer microparticle intermediate I dispersion of this embodiment is 170 nm, and the acid neutralization equivalent of the B1-derived polymer microparticle intermediate I dispersion of this embodiment is 2.2 mmol KOH / g on a polymer dry basis.

[0051] The B1-derived polymer microparticle intermediate I dispersion of this embodiment is prepared by the following steps: Step A1 is the preparation of the aqueous phase. 100 parts by mass of heptadecanylhydroxyethylimidazoline and 15 parts by mass of benzotriazole are added to deionized water. After stirring and dissolving, the pH of the aqueous phase is adjusted to 7.5 using sodium hydroxide solution, controlling the total mass fraction of heptadecanylhydroxyethylimidazoline and benzotriazole to be 12 wt%, thus obtaining the aqueous phase. Step A2 is the preparation of the organic continuous phase. 15 parts by mass of the nonionic surfactant Triton X-100 (based on 100 parts by mass of heptadecanylhydroxyethylimidazoline in step A1) are added to an organic phase containing 700 parts by mass of sulfolane and 50 parts by mass of n-heptane (based on 100 parts by mass of heptadecanylhydroxyethylimidazoline in step A1), and the mixture is stirred until homogeneous, thus obtaining the organic continuous phase. Step A3 is the preparation of the organic continuous phase at a temperature... The organic continuous phase of this embodiment is stirred at a temperature of 35°C. The aqueous phase of this embodiment is added to the organic continuous phase of this embodiment at a substantially constant flow rate within 1.0 h to form a stable emulsion. Step A4 involves heating the emulsion of this embodiment to 70°C under an inert atmosphere and adding the crosslinking agent hexamethylene diisocyanate to the emulsion of this embodiment within 0.8 h. The total amount of the crosslinking agent added is 25 mol% relative to the molar number of the B1 structural unit. Step A5 involves cooling the reaction system to 38°C, removing part of the n-heptane and water from the system under reduced pressure, removing the excess aqueous phase through phase separation, adding sulfolane to adjust the solid content of the dispersion to 25 wt%, filtering to remove large particles with a particle size greater than 1 μm, and filling under nitrogen protection to obtain the B1-derived polymer microparticle intermediate I dispersion of this embodiment.

[0052] The sulfolane extractant A1 in this embodiment does not contain azeotropic aromatic hydrocarbons. The aromatic amine component B2 in this embodiment is the aromatic amine acid scavenger N-phenyl-1-naphthylamine. The benzotriazole component B3 in this embodiment is the metal passivator sodium benzotriazole. The adjuvant in this embodiment is a flow improver. The flexible chain segment structural unit in this embodiment is derived from 1,6-hexanediol.

[0053] After six months of continuous operation in an industrial plant using the sulfolane-based extractant ternary inhibitor composition of this embodiment as the extractant, the acid value of the sulfolane-based extractant ternary inhibitor composition of this embodiment was 0.009 mg KOH / g. Under simulated operating conditions, the corrosion rate on carbon steel was 0.018 mm per year; compared to a control system using only sulfolane-based extractant A1 without the addition of B1 derivative polymer microparticle intermediate I dispersion, aromatic amine component B2, and benzotriazole component B3 under the same operating conditions, the corrosion rate was reduced by 70%.

[0054] The preparation method of the ternary inhibitory composition of the sulfolane extractant in this embodiment includes the following steps: Step S1 is to prepare a dispersion of B1-derived polymer microparticle intermediate I with a solid content of 25 wt%; Step S2 is to place 100 parts by mass of the sulfolane extractant A1 of this embodiment into a solvent tank equipped with a stirring device at a temperature of 45°C, add a metered amount of the B1-derived polymer microparticle intermediate I dispersion of this embodiment, and, based on the sulfolane extractant A1, make the concentration of polymer dry solids equivalent to 50 ppm, and stir for 40 min to make the B1-derived polymer microparticle intermediate I dispersion of this embodiment conform to the sulfolane extractant of this embodiment. The mixture is uniformly dispersed in extractant A1; Step S3 involves adding aromatic amine component B2 and benzotriazole component B3 to the system obtained in step S2 using a metering pump. Based on sulfolane extractant A1, the dosage of aromatic amine component B2 is 60 ppm and the dosage of benzotriazole component B3 is 80 ppm. The mixture is stirred for 35 min at 45°C to obtain a homogeneous sulfolane extractant ternary inhibitory composition; Step S4 involves testing the density, viscosity, and conductivity of the sulfolane extractant ternary inhibitory composition obtained in step S3. Once the above physical properties are stable, the sulfolane extractant ternary inhibitory composition of this embodiment is obtained.

[0055] Features of this embodiment: This embodiment adopts an economical low-inhibitor content scheme, with sulfolane content of 98.5wt% (relatively high) and water content of 1.5wt% (relatively low). In the polymer dry base of the B1-derived polymer microparticle intermediate I dispersion, the B1 structural unit is 40mol% (relatively low), the benzotriazole structural unit C1 is 10mol% (relatively low), the crosslinking structural unit is 30mol% (up to the upper limit), and the flexible segment structural unit is 20mol% (up to the upper limit). The median particle size D50 of the polymer microparticles is 170nm (relatively large), and the acid neutralization equivalent is 2.2mmolKOH / g (close to the lower limit). The B1 content in the composition... The derivative polymer microparticle intermediate I dispersion has a dry basis content of 50 ppm, an aromatic amine component B2 content of 60 ppm, and a benzotriazole component B3 content of 80 ppm (all relatively low). With the addition of 10 ppm of flowability improver, this scheme improves mechanical stability and flowability through high crosslinking degree and high flexible segment content. The larger particle size helps to reduce viscosity, the low inhibitor content reduces cost, the corrosion rate is reduced by up to 70%, and the acid value is controlled below 0.01 mg KOH / g. It is suitable for working environments with weak corrosiveness, and is particularly suitable for light aromatic hydrocarbon extraction units that process low-acid raw materials or small and medium-sized production units with high requirements for economy and flowability.

[0056] Example 4

[0057] This embodiment provides a ternary inhibitory composition based on sulfolane extractant A1, wherein the amounts of each component are relative to the mass of sulfolane extractant A1. Sulfolane extractant A1 in this embodiment comprises: 95.5 wt% sulfolane, 4.5 wt% water, and 0 wt% azeotropic aromatic hydrocarbon, wherein the sum of the mass fractions of the components is 100 wt%. The composition of this embodiment also includes a B1-derived polymer microparticle intermediate I dispersion dispersed in the sulfolane extractant A1, with a polymer dry basis solids content of 180 ppm, wherein B1 represents a structural unit derived from heptadecanylhydroxyethylimidazoline, and the B1-derived polymer microparticle intermediate I dispersion is an oil-in-water polymer microparticle dispersion. The composition of this embodiment also includes an aromatic amine component B2 at 30 ppm, a benzotriazole component B3 at 60 ppm, and an adjuvant at 45 ppm.

[0058] The polymer dry base of the B1-derived polymer microparticle intermediate I dispersion in this embodiment is composed of the following structural units: 35 mol% of B1 structural units derived from heptadecanylhydroxyethylimidazoline; 28 mol% of benzotriazole structural units C1 derived from benzotriazole compounds; 27 mol% of crosslinking structural units derived from a mixture of 1,4-butanediol diglycidyl ether and p-dichloromethylbenzene in a molar ratio of 1:1; and 10 mol% of flexible segment structural units derived from a mixture of polyethylene glycol 400 and neopentyl glycol in a mass ratio of 1:1, wherein the sum of the molar fractions of the above structural units is 100 mol. In this embodiment, the median particle size (D50) of the polymer microparticles in the B1-derived polymer microparticle intermediate I dispersion is 190 nm. Based on the dry polymer basis, the acid neutralization equivalent of the B1-derived polymer microparticle intermediate I dispersion in this embodiment is 2.1 mmol KOH / g.

[0059] The B1-derived polymer microparticle intermediate I dispersion of this embodiment is prepared by the following steps: Step A1 is the preparation of the aqueous phase. 100 parts by mass of heptadecanylhydroxyethylimidazoline and 12 parts by mass of a mixture of benzotriazole and toluenetriazole in a 1:1 mass ratio are added to deionized water. After stirring and dissolving, the pH of the aqueous phase is adjusted to 9.3 using sodium hydroxide solution, controlling the total mass fraction of the mixture of heptadecanylhydroxyethylimidazoline and benzotriazole compounds to be 8 wt%, thus obtaining the aqueous phase. Step A2 is the preparation of the organic continuous phase. 8 parts by mass of the nonionic surfactant Triton X-100 (based on 100 parts by mass of heptadecanylhydroxyethylimidazoline in step A1) are added to an organic phase containing 750 parts by mass of sulfolane and 20 parts by mass of n-heptane (based on 100 parts by mass of heptadecanylhydroxyethylimidazoline in step A1), and the mixture is stirred until homogeneous, thus obtaining the organic continuous phase. Step A3 is the preparation of the organic continuous phase at a temperature... The organic continuous phase of this embodiment was stirred at a temperature of 22°C. The aqueous phase of this embodiment was added to the organic continuous phase of this embodiment at a substantially constant flow rate over 2.8 hours to form a stable emulsion. Step A4 involved heating the emulsion of this embodiment to 75°C under an inert atmosphere and adding a mixture of crosslinking agent 1,4-butanediol diglycidyl ether and p-dichloromethylbenzene in a molar ratio of 1:1 to the emulsion of this embodiment over 0.6 hours. The total amount of the crosslinking agent added was 28 mol% relative to the molar number of the B1 structural unit. Step A5 involved cooling the reaction system to 26°C, removing some of the n-heptane and water from the system under reduced pressure, removing the excess aqueous phase through phase separation, adding sulfolane to adjust the solid content of the dispersion to 38 wt%, filtering to remove large particles with a particle size greater than 1 μm, and filling the mixture under nitrogen protection to obtain the B1-derived polymer microparticle intermediate I dispersion of this embodiment.

[0060] The sulfolane extractant A1 in this embodiment does not contain azeotropic aromatic hydrocarbons. The aromatic amine component B2 in this embodiment is the aromatic amine acid scavenger diphenylamine. The benzotriazole component B3 in this embodiment is a metal passivating agent, a mixture of benzotriazole and toluenetriazole in a 1:1 mass ratio. The adjuvant in this embodiment is a mixture of defoamer and dispersant stabilizer in a 1:1 mass ratio. The flexible segmental structural unit in this embodiment is derived from a mixture of polyethylene glycol 400 and neopentyl glycol in a 1:1 mass ratio.

[0061] After 12 months of continuous operation in an industrial plant using the sulfolane-based extractant ternary inhibitor composition of this embodiment as the extractant, the acid value of the sulfolane-based extractant ternary inhibitor composition of this embodiment was 0.009 mg KOH / g. Under simulated operating conditions, the corrosion rate on carbon steel was 0.016 mm per year; compared with the control system using only sulfolane-based extractant A1 without the addition of B1 derivative polymer microparticle intermediate I dispersion, aromatic amine component B2, and benzotriazole component B3 under the same operating conditions, the corrosion rate was reduced by 73%.

[0062] The preparation method of the ternary inhibitory composition of the sulfolane extractant in this embodiment includes the following steps: Step S1 is to prepare a dispersion of B1-derived polymer microparticle intermediate I with a solid content of 38 wt%; Step S2 is to place 100 parts by mass of the sulfolane extractant A1 of this embodiment into a solvent tank equipped with a stirring device at a temperature of 32°C, add a metered amount of the B1-derived polymer microparticle intermediate I dispersion of this embodiment, and, based on the sulfolane extractant A1, make the concentration converted to polymer dry basis solids 180 ppm, and stir for 110 min to make the B1-derived polymer microparticle intermediate I dispersion of this embodiment in the sulfolane extractant composition of this embodiment. The sulfolane extractant A1 is uniformly dispersed in the system. Step S3 involves adding aromatic amine component B2 and benzotriazole component B3 to the system obtained in step S2 using a metering pump. Based on sulfolane extractant A1, the dosage of aromatic amine component B2 is 30 ppm, and the dosage of benzotriazole component B3 is 60 ppm. The mixture is stirred for 58 minutes at 32°C to obtain a homogeneous sulfolane extractant ternary inhibitory composition. Step S4 involves testing the density, viscosity, and conductivity of the sulfolane extractant ternary inhibitory composition obtained in step S3. Once these physical properties stabilize, the sulfolane extractant ternary inhibitory composition of this embodiment is obtained. In step S3, an additional 8 ppm of the nonionic surfactant Triton X-100 is added as a dispersion stabilizer.

[0063] Features of this embodiment: This embodiment employs a boundary exploration scheme with a wide range of parameter adaptability. The sulfolane content is 95.5 wt%, the water content is 4.5 wt%, and the B1-derived polymer microparticle intermediate I dispersion contains 35 mol% B1 structural units, 28 mol% benzotriazole structural units (C1), 27 mol% crosslinking structural units, and 10 mol% flexible segment structural units in the polymer dry base. The median particle size (D50) of the polymer microparticles is 190 nm, and the acid neutralization equivalent is 2.1 mm. The composition contains 180 ppm dry basis KOH / g of B1-derived polymer microparticle intermediate I dispersion, 30 ppm aromatic amine component B2, and 60 ppm benzotriazole component B3. It also includes 45 ppm of additives and 8 ppm of nonionic surfactant Triton X-100. The preparation process involves an aqueous phase pH of 9.3, a total mass fraction of 8 wt%, 750 parts by mass of sulfolane, 20 parts by mass of n-heptane, and 8 parts by mass of Triton X-100. The following parameters were used in the preparation method: emulsification temperature 22℃, feeding time 2.8h, reaction temperature 75℃, crosslinking agent addition time 0.6h, crosslinking agent dosage 28mol%, cooling temperature 26℃, solid content 38wt%, preparation temperature 32℃, and stirring time 110min and 58min. This scheme demonstrates the wide adaptability and boundary feasibility of the technical solution through a combination design of multiple parameters close to the range boundary. It can still maintain good anti-corrosion performance under conditions of high water content and low sulfolane content. The low dosage of aromatic amine component B2 and benzotriazole component B3 is compensated by the high content of B1-derived polymer microparticle intermediate I dispersion and high benzotriazole structural unit content. High crosslinking degree and large particle size ensure long-term stability, corrosion rate is reduced by up to 73%, and acid value is controlled below 0.01mgKOH / g. It is suitable for industrial plants that need to operate within a wide parameter range, especially for aromatic extraction plants with large fluctuations in raw material composition or frequent adjustment of operating parameters, as well as large-scale continuous production plants that need to operate for long periods of time.

[0064] Comparative Example 1: Basically the same as Example 1, except that the polymer dry solids content of the B1-derived polymer microparticle intermediate I dispersion is 5 ppm, while the amounts of other components and preparation conditions remain unchanged.

[0065] Comparative Example 2: It is basically the same as Example 1, except that the polymer dry solids content of the B1-derived polymer microparticle intermediate I dispersion is 250 ppm, while the amounts of other components and preparation conditions remain unchanged.

[0066] Comparative Example 3: It is basically the same as Example 1, except that the molar fraction of B1 structural unit in the polymer dry base of the B1-derived polymer microparticle intermediate I dispersion is 25 mol%, and the molar fraction of other structural units is adjusted accordingly to make the total 100 mol%, while other conditions remain unchanged.

[0067] Comparative Example 4: It is basically the same as Example 1, except that the molar fraction of B1 structural unit in the polymer dry base of the B1-derived polymer microparticle intermediate I dispersion is 75 mol%, and the molar fraction of other structural units is adjusted accordingly to make the total 100 mol%, while other conditions remain unchanged.

[0068] Comparative Example 5: It is basically the same as Example 1, except that the molar fraction of benzotriazole structural unit C1 in the polymer dry base of the B1-derived polymer microparticle intermediate I dispersion is 3 mol%, and the molar fractions of other structural units are adjusted accordingly to make the total 100 mol%, while other conditions remain unchanged.

[0069] Comparative Example 6: It is basically the same as Example 1, except that the molar fraction of benzotriazole structural unit C1 in the polymer dry base of B1-derived polymer microparticle intermediate I dispersion is 35 mol%, and the molar fraction of other structural units is adjusted accordingly to make the total 100 mol%, while other conditions remain unchanged.

[0070] Comparative Example 7: Basically the same as Example 1, except that the molar fraction of crosslinked structural units in the polymer dry base of the B1-derived polymer microparticle intermediate I dispersion is 3 mol%, and the molar fraction of other structural units is adjusted accordingly to make the total 100 mol%, while other conditions remain unchanged.

[0071] Comparative Example 8: It is basically the same as Example 1, except that the molar fraction of the crosslinked structural unit in the polymer dry base of the B1-derived polymer microparticle intermediate I dispersion is 35 mol%, and the molar fraction of other structural units is adjusted accordingly to make the total 100 mol%, while other conditions remain unchanged.

[0072] Comparative Example 9: Basically the same as Example 1, except that the median particle size D50 of the polymer microparticles in the B1 derivative polymer microparticle intermediate I dispersion is 60 nm. This was achieved by adjusting the emulsification temperature in step A3 to 15 °C, the feeding time to 3.5 h, and the amount of nonionic surfactant Triton X-100 in step A2 to 35 parts by mass. Other conditions remained unchanged.

[0073] Comparative Example 10: It is basically the same as Example 1, except that the median particle size D50 of the polymer microparticles in the B1 derivative polymer microparticle intermediate I dispersion is 220 nm. This is achieved by adjusting the emulsification temperature of step A3 to 40 °C, the feeding time to 0.8 h, and the amount of nonionic surfactant Triton X-100 in step A2 to 15 parts by mass. Other conditions remain unchanged.

[0074] Comparative Example 11: It is basically the same as Example 1, except that the amount of aromatic amine component B2 is 10 ppm, while the amounts of other components and preparation conditions remain unchanged. This comparative example is intended to demonstrate that a low content of aromatic amine acid scavenger leads to an accelerated accumulation rate of acidic substances and a deterioration in acid value stability.

[0075] Comparative Example 12: Basically the same as Example 1, except that the amount of benzotriazole component B3 is 30 ppm, while the amounts of other components and preparation conditions remain unchanged.

[0076] Comparative Example 13: It is basically the same as Example 1, except that the B1-derived polymer microparticle intermediate I dispersion (i.e., the content is 0 ppm) is not added, and only the aromatic amine component B2 is retained at 100 ppm and the benzotriazole component B3 at 120 ppm. Other conditions remain unchanged. This comparative example is to demonstrate that the lack of polymer microparticles leads to the absence of the interfacial selective enrichment mechanism, the loss of the ternary synergistic anticorrosion effect, and a significant deterioration in long-term anticorrosion performance.

[0077] Carbon steel corrosion rate test

[0078] Test Subject: Corrosion protection performance of a ternary inhibitor composition of sulfolane-based extractant on carbon steel (Q235 material). Test Objective: To evaluate the corrosion rate and long-term protective effect of the composition on carbon steel under simulated industrial extraction conditions. Test Principle: The corrosion rate is quantitatively assessed through immersion corrosion experiments and weight loss methods, reflecting the passivation film construction ability and corrosion inhibition efficiency of the inhibitor component in the extractant system at the metal / solvent interface. Experimental Method: A static immersion method was used. Q235 carbon steel test pieces (50mm×25mm×3mm in size), after surface rust removal, grinding to 800-grit sandpaper, acetone degreasing, cleaning with anhydrous ethanol, and drying, were immersed in 250mL of test solution. The test conditions were: temperature 120±2℃, atmospheric pressure nitrogen protection, immersion time 720h (simulating one month of working conditions). After the test, the test pieces were removed, and corrosion products were removed with a 10% hydrochloric acid solution (containing 0.5% hexamethylenetetramine corrosion inhibitor). After cleaning and drying, the samples were accurately weighed. Three parallel samples were prepared for each group. Key parameters: temperature 120±2℃, immersion time 720h, specimen size 50mm×25mm×3mm, surface treatment to 800 mesh, nitrogen protection, parallel samples n=3. Data processing: corrosion rate ν=87.6×(m0-m1) / (A×t×ρ), where m0 and m1 are the mass before and after corrosion (g), A is the exposed area (cm²), t is the time (h), and ρ is the density of carbon steel 7.85g / cm³. Results are expressed in mm / year. The mean ± standard deviation (n=3) is calculated. Corrosion rate reduction rate = (ν0-ν) / ν0×100%, where ν0 is the corrosion rate of the blank control group.

[0079] Acid value stability test

[0080] Test Subject: The accumulation level of acidic substances in a ternary inhibitory composition of sulfolane extractant after long-term operation. Test Objective: To evaluate the ability of aromatic amine acid scavenger B2 in the composition to capture acidic substances and its anti-acidification stability. Test Principle: The free acid content is determined by potentiometric titration, indirectly reflecting the accumulation rate of acidic oxidation products in the extractant system and the long-term effectiveness of the inhibitor. Experimental Method: An accelerated aging test was conducted. 100 mL of the test solution was placed in a 250 mL three-necked flask equipped with a reflux condenser and oxidized and aged for 168 h at 140±2℃ and a dry air flow rate of 50 mL / min (simulating 6 months of operation). 5 mL samples were taken every 24 h, cooled to room temperature, and then titrated with 0.1 mol / L potassium hydroxide-isopropanol standard solution using an automatic potentiometric titrator to the endpoint pH=11.0. The determination was performed in triplicate. Standard Basis: Refer to GB / T 7304-2014 "Determination of Acid Value of Petroleum Products - Potentiometric Titration Method". Key parameters: aging temperature 140±2℃, air flow rate 50mL / min, aging time 168h, sampling interval 24h, titrant concentration 0.1mol / L KOH, endpoint pH=11.0, sample volume 5mL, parallel determination n=3. Data processing: acid value AV=(V×c×56.1) / m, where V is the volume of KOH consumed (mL), c is the KOH concentration (mol / L), m is the sample mass (g), and 56.1 is the molar mass of KOH. Results are expressed as mgKOH / g. The mean ± standard deviation (n=3) was calculated, and the acid value change curve with aging time was plotted to evaluate the acid resistance stability.

[0081] Polymer microparticle size distribution test

[0082] Test Subject: Particle size distribution and stability of B1-derived polymer microparticle intermediate I dispersion in sulfolane-based extractant A1. Test Objective: To evaluate the size uniformity, dispersion stability, and whether the median particle size (D50) of the polymer microparticles is within the specified range. Test Principle: Based on dynamic light scattering (DLS) technology, the particle size distribution is calculated using the Stokes-Einstein equation by measuring the intensity fluctuations of laser scattered light caused by the Brownian motion of particles. Experimental Method: The B1-derived polymer microparticle intermediate I dispersion was diluted with sulfolane-based extractant A1 to approximately 0.01 wt% on a dry basis. After thorough shaking, the mixture was allowed to stand for 30 min to eliminate air bubbles. A 1 mL sample was placed in a disposable cuvette and measured using a Malvern Zetasizer Nano ZS dynamic light scattering instrument at 25.0 ± 0.1℃ and a scattering angle of 173°. Each sample was measured 5 times, with each measurement lasting 120 s. The median particle size (D50), polydispersity index (PDI), and particle size distribution curve were automatically calculated. Standard Basis: Refer to ISO 22412-2017 "Particle size analysis – Dynamic light scattering method". Key Parameters: Test temperature 25.0±0.1℃, scattering angle 173°, sample solid content 0.01wt%, settling time 30min, number of measurements n=5, single measurement time 120s, laser wavelength 633nm. Data Processing: Output D50 mean ± standard deviation (n=5), PDI value, particle size distribution histogram and cumulative distribution curve, exported CSV file including Diameter (nm), Volume (%), and Cumulative_Volume (%) fields for Origin plotting.

[0083] Acid neutralization equivalent test

[0084] Test Subject: Acid neutralization capacity of B1-derived polymer microparticle intermediate I dispersion. Test Objective: To quantitatively evaluate the content of basic structural units (B1 imidazoline structure) in the polymer dry basis and its buffering capacity against acidic substances. Test Principle: The amount of acid required to completely neutralize the basic structural units in a unit mass of polymer dry basis by standard acid is determined by acid-base titration, and converted to an equivalent amount of KOH, reflecting the acid-capturing capacity and pH buffering performance of the polymer microparticles. Experimental Method: Accurately weigh approximately 0.5 g of B1-derived polymer microparticle intermediate I dispersion (converted to polymer dry basis) into a 250 mL Erlenmeyer flask, add 50 mL of anhydrous isopropanol to dissolve, add 2-3 drops of phenolphthalein indicator, and use...

[0085] Titrate with 0.1000 mol / L hydrochloric acid-isopropanol standard solution until the solution just turns from pink to colorless and no color reappears within 30 seconds. Record the volume consumed. Perform three parallel determinations. Perform the blank test using the same method.

[0086] Standard Basis: Refer to GB / T 6743-1986 "Determination of Acid Value of Paints and Varnishes". Key Parameters: Sample amount approximately 0.5g of dry polymer, solvent 50mL anhydrous isopropanol, titrant 0.1000mol / L hydrochloric acid-isopropanol standard solution (calculated as HCl), indicator 2-3 drops of phenolphthalein, endpoint criterion is the fading of the faint red color and the absence of color within 30s, parallel determination n=3, titration rate approximately 2mL / min. Data Processing: Acid neutralization equivalent ANE=(V-V0)×c / m, where V and V0 are the volumes of hydrochloric acid standard solution consumed by the sample and blank, respectively (mL), c is the concentration of hydrochloric acid standard solution (mol / L, calculated as HCl), and m is the sample mass converted to dry polymer (g). Results are expressed as equivalent mmolKOH / g, and the mean ± standard deviation (n=3) is calculated.

[0087] Dispersion stability test

[0088] Test Subject: Long-term dispersion stability of B1-derived polymer microparticle intermediate I dispersion in a ternary inhibitory composition of sulfolane-based extractant. Test Objective: To evaluate the anti-aggregation and anti-sedimentation capabilities of polymer microparticles in highly polar solvent systems, as well as the retention time of dispersion uniformity under ppm-level low solids content conditions. Test Principle: The particle size variation over time was monitored using multi-angle dynamic light scattering, combined with turbidimetry and centrifugal accelerated stability analysis to assess the thermodynamic and kinetic stability of the dispersion system. Experimental Methods: 50 mL of the ternary inhibitory composition of sulfolane extractant was placed in a 60 mL stoppered colorimetric tube and allowed to stand at a constant temperature of 25±1℃. Samples were taken at 0h, 24h, 72h, 168h, 336h, and 720h to determine the median particle size (D50) and turbidity (using a WGZ-200 turbidimeter, 10 mm path length, 660 nm wavelength), with 3 parallel samples. Another 10 mL sample was centrifuged at 4000 rpm for 30 min (centrifugation acceleration stability test), and the changes in sedimentation volume fraction and supernatant transmittance were observed. Key Parameters: Test temperature 25±1℃, longest standing time 720h, 6 sampling time points, particle size measurement conditions same as in Experiment 3, turbidity measurement wavelength 660 nm, centrifugation conditions 4000 rpm × 30 min, parallel samples n=3. Data Processing: D50 and turbidity change curves were plotted over time, and the particle size growth rate was calculated as (D50 / T50) / (T ... t -D500) / D500×100%, the exported CSV file contains Time(h), D50(nm), and Turbidity(NTU) fields.

[0089] Electrochemical Impedance Spectroscopy (EIS) Measurement

[0090] Test Subject: Electrochemical properties of the passivation film formed on carbon steel surface by a ternary inhibitor composition of sulfolane extractant. Test Objective: To quantitatively evaluate the compactness, charge transfer resistance, and interfacial capacitance of the passivation film using AC impedance spectroscopy, revealing the synergistic anti-corrosion mechanism of the ternary inhibitor system. Test Principle: A small sinusoidal perturbation voltage is applied to the carbon steel working electrode at open-circuit potential, and the impedance response at different frequencies is measured. Parameters such as solution resistance Rs, charge transfer resistance Rct, and double-layer capacitance Cdl are obtained by equivalent circuit fitting of Nyquist and Bode plots. Experimental Method: A three-electrode system is used (working electrode is a Q235 carbon steel sheet with an exposed area of ​​1 cm², counter electrode is a platinum sheet, and reference electrode is a saturated calomel electrode). The carbon steel electrode is immersed in the test solution for 2 hours at 25±1℃ under nitrogen protection until the open-circuit potential stabilizes. The EIS is measured using a Gamry Interface 1010E electrochemical workstation with a frequency range of 10 Hz. 5 -10⁻²Hz, AC disturbance amplitude 10mV, 10 cycles of data collected at each frequency point, 3 samples measured in parallel, parameters obtained by fitting the equivalent circuit Rs(Cdl[RctW]) using ZView software. Standard basis: ASTM G106-2015 "Standard Practice for Electrochemical Impedance Spectroscopy Measurement". Key parameters: test temperature 25±1℃, exposure area 1cm², immersion stabilization time 2h, frequency range 10 5 -10⁻²Hz, perturbation amplitude 10mV, nitrogen protection, parallel samples n=3. Data processing: Output Rct mean ± standard deviation (n=3), export CSV file containing Freq(Hz), Zreal(Ω), Zimag(Ω) fields.

[0091] Figure 1 The image shows XPS depth profiles of Fe, N, O, and C atomic fractions for Example 1, corresponding to a steel substrate interface with 100 ppm polymer microparticles. Characterization was performed using X-ray photoelectron spectroscopy (XPS) depth profiles. Fixed parameters included: consistent substrate material and pretreatment process; constant sputtering rate and step size; constant analytical region size and X-ray incident conditions; and uniformly set XPS analysis energy and bandwidth. Variations were achieved with polymer microparticle amounts of 100 ppm (Example 1), 5 ppm (Comparative Example 1), and 0 ppm (Comparative Example 13), resulting in different amounts of nitrogen-containing organic modified layers formed at the interface. The results show that in the 0–5 nm interface region, the N atom fraction of Example 1 is significantly higher than that of Comparative Example 1 and Comparative Example 13, and it decreases gradually with increasing depth, while the Fe signal gradually transitions from low to high. This indicates that an appropriate amount of polymer microparticles can construct a continuous nitrogen-containing organic layer on the surface of the steel substrate, increase the organic content of the interface and form a smooth gradient transition structure, laying the foundation for the formation of a stable organic protective layer on the metal surface.

[0092] Figure 2 The XPS depth profiles for Comparative Example 1 show the atomic fractions of Fe, N, O, and C, corresponding to a steel substrate interface with a polymer microparticle addition of 5 ppm. Characterization was performed using X-ray photoelectron spectroscopy (XPS) depth profiling. Fixed parameters included: consistent substrate material and pretreatment process; constant sputtering rate and step size; constant analysis zone size and X-ray incident conditions; and uniformly set XPS analysis energy and bandwidth. Variations were achieved with polymer microparticle additions of 100 ppm (Example 1), 5 ppm (Comparative Example 1), and 0 ppm (Comparative Example 13), resulting in different amounts of nitrogen-containing organic modified layers at the interface. Compared to Example 1, Comparative Example 1 showed a significantly lower N atomic fraction in the 0–5 nm interface region, with a more gradual decay with depth and a less pronounced increase in Fe signal. The nitrogen-containing organic layer at the interface was less continuous and abundant than in Example 1.

[0093] Figure 3 The XPS depth profile of Comparative Example 13 shows the atomic fractions of Fe, N, O, and C, corresponding to a steel substrate interface with 0 ppm polymer microparticles. The characterization method was X-ray photoelectron spectroscopy (XPS) depth profile, with the following parameters kept constant: substrate material and pretreatment process; constant sputtering rate and step size; constant analysis zone size and X-ray incident conditions; and uniformly set XPS analysis energy and bandwidth. The varying parameters were the polymer microparticle amounts: 100 ppm (Example 1), 5 ppm (Comparative Example 1), and 0 ppm (Comparative Example 13). The results show that Comparative Example 13 exhibited almost no significant N enrichment, with Fe dominating at the surface. The interface did not form a significant nitrogen-containing organic modification layer, a stark contrast to Example 1, which showed significant N enrichment and a gentle gradient transition in the 0–5 nm region. This further illustrates that the absence of polymer microparticles is detrimental to constructing an organically modified interface structure on the steel substrate surface that facilitates coating adhesion.

[0094] Figure 4The high-resolution photoelectron spectroscopy (HPS) fitting images of Fe 2p in Example 1 and Comparative Example 1 were obtained. The characterization method was high-resolution Fe 2p scanning using X-ray photoelectron spectroscopy (XPS) followed by multi-peak fitting to analyze the Fe–N and Fe2O3 components. Fixed parameters included consistent matrix material and pretreatment steps, constant vacuum level in the test chamber and X-ray source power, unchanged analytical region and sampling depth, and uniformly set peak shapes and background functions. Variation parameters included the amount of polymer microparticles added in the system: 100 ppm in Example 1 and 5 ppm in Comparative Example 1. The results showed that the peak area related to the Fe–N bond at approximately 709.8 eV in the Example 1 sample was significantly higher than that in Comparative Example 1, while the high binding energy peak related to Fe2O3 was relatively weakened. This indicates that the higher polymer microparticle content promoted the formation of Fe–N coordination or complex structures on the steel matrix surface and inhibited excessive surface oxidation, resulting in a stable organic coordination layer at the interface. This supports the enrichment of nitrogen-containing organic layers observed in the depth analysis from a valence state perspective.

[0095] Figure 5 Example 1, Comparative Example 1, and Comparative Example 13 are histograms of the average N atom fraction at the interface in the 0–5 nm range. The characterization method is to obtain the N_at percentage content by integrating and averaging the 0–5 nm range based on X-ray photoelectron spectroscopy (XPS) depth profiling data. The fixed parameters are that the sample matrix type and surface pretreatment conditions are consistent, the XPS test and sputtering rules are exactly the same as those of the depth profiling, and the data processing window width and averaging method are consistent. The variable parameters are that the amount of polymer microparticles added is 100 ppm for Example 1, 5 ppm for Comparative Example 1, and 0 ppm for Comparative Example 13. The results showed that the average N atomic fraction at the interface of Example 1 in the 0–5 nm range was about 16%, which was significantly higher than that of Comparative Example 1 (about 6%) and Comparative Example 13 (about 2%). The N content at the interface increased monotonically with the increase of polymer microparticles, indicating that increasing the amount of polymer microparticles can form a thicker and more continuous nitrogen-enriched zone on the surface of the steel, thereby enhancing the proportion of organic phase at the interface. This trend is corroborated by the depth profile curve and the Fe2p valence state analysis, which together show that the chemical environment and interface structure of the steel surface can be effectively adjusted by controlling the content of polymer microparticles.

[0096] Figure 6The nanoparticle size distribution of Examples 1, 9, and 10 in sulfolane-based extractant A1 is shown. The fixed parameters are: system using sulfolane-based extractant A1; test method using dynamic light scattering volume distribution mode; measurement temperature 25°C; optical path position 4.65 mm; attenuator setting 7; and measurement of each sample based on the same optical path and related analytical conditions. The varying parameters are the volume distribution particle size D50 and distribution width of Examples 1, 9, and 10, ranging from approximately 60 nm to 220 nm. Example 1 has a volume distribution D50 of approximately 140 nm, a narrow distribution, and a highly concentrated main peak. Comparative Example 9 has a main peak of approximately 60 nm but a wider distribution. Comparative Example 10 has a main peak shifted towards approximately 220 nm and exhibits a certain degree of high-size tailing. This indicates that, under the same sulfolane system and test conditions, controlling the nanoparticle size distribution to a moderate D50 and a moderately narrow distribution is beneficial for obtaining stable, repeatable scattering signals and a uniform nanodispersion state, laying the particle size structure foundation for subsequent dispersion stability evaluation.

[0097] Figure 7 The dispersion stability evaluation graphs of the median volumetric particle size (D50) of Examples 1–4 and Comparative Example 9 during 720 h of storage are shown. The fixed parameters are: the initial dispersed solid content is the same, the system is sulfolane-based extractant A1, the test method is dynamic light scattering median volumetric particle size (D50) measurement, the measurement temperature is 25 ℃, and the sampling time points are 0 h, 24 h, 72 h, 168 h, 360 h, and 720 h. The same refractive index and viscosity model is used for fitting at each time point. The changing parameters are: the initial D50 and the 720 h particle size growth rate of Examples 1, 2, 3, 4, and Comparative Example 9 range from about 3.5% to 42%. The D50 curves of Examples 1–4 showed a slow and smooth increase within the range of 0–720 h, with the growth rate controlled at approximately 3.5%–6.5% over 720 h. The curves exhibited no abrupt inflection points and had a small error range, indicating that the particles maintained a relatively stable dispersion state during long-term storage. In contrast, the D50 of Comparative Example 9 showed a significant and continuous increase from approximately 60 nm, with a growth rate of approximately 42% over 720 h. The curve showed a sharp increase and a larger error range, reflecting significant aggregation and uncontrolled particle size. These results demonstrate that under the same medium and testing conditions, by rationally controlling the formulation structure, the long-term D50 growth rate can be compressed to a low level, achieving stable nano-dispersion at the 720-h scale. In contrast, an unreasonable formulation exhibits significant unstable behavior within the same timescale.

[0098] Figure 8Box plots of the statistical distribution of particle size growth rate after 720 h storage for Examples 1–4 and Comparative Examples 1–13. The fixed parameters were that the system was sulfolane-based extractant A1, the initial dispersion concentration and measurement conditions were consistent with the time evolution test, and the 720 h particle size growth rate was calculated from the relative change of the dynamic light scattering volume median particle size D50. The data of each sample were based on the statistical distribution formed by multiple repeated tests. The varying parameters were the mean 720 h particle size growth rate of Examples 1–4 and Comparative Examples 1–13 from about 3.5% to 42% and their standard deviation. The box plots of Examples 1–4 are generally concentrated in the range of approximately 3.5%–6.5%, with small box heights and limited outliers, indicating a high degree of consistency in particle size growth behavior among different replicate samples, and demonstrating good batch reproducibility and long-term dispersion stability. The box plots of most comparative samples show a significant overall increase in height, with some comparative samples having median values ​​exceeding 20% ​​or even approaching or surpassing 40%. Simultaneously, the box height and whisker length are significantly increased, and a few samples exhibit high-value outliers, reflecting a substantial increase in particle size over time and significant fluctuations between samples. These statistical results corroborate the trends in the time evolution curves, indicating that the formulations used in this scheme can significantly suppress nanoparticle size growth under long-term storage conditions and maintain stable and controllable particle size evolution behavior in multiple batch replicates.

[0099] As can be seen from the performance of the examples and comparative examples in Table 1, all four examples exhibit significantly better overall corrosion protection performance and long-term stability than the comparative examples. Among them, Example 2, due to the use of an enhanced corrosion protection formula (high B1 structural unit 60 mol%, high benzotriazole structural unit C1), shows superior performance. The method using 20 mol% KOH (with a smaller particle size of 110 nm, a higher acid neutralization equivalent of 3.0 mmol KOH / g, and higher inhibitor content of 160 ppm and 180 ppm) achieved the lowest corrosion rate of 0.012 mm / year and an acid value of 0.007 mg KOH / g, with a corrosion rate reduction rate as high as 80%, making it suitable for harsh working conditions with strong corrosiveness. Example 1, as a stable solution with medium parameter configuration, showed balanced performance indicators, with a corrosion rate of 0.015 mm / year, an acid value of 0.008 mg KOH / g, a corrosion rate reduction rate of 75%, and good dispersion stability (particle size increase rate of only 4.2% over 720 h), making it suitable for long-term stable operation of large-scale aromatic extraction units. Although Examples 3 and 4 used lower inhibitor content and larger particle size, they still maintained good anti-corrosion effects through high cross-linking degree and high flexible segment content, with corrosion rates of 0.018 mm / year and 0.016 mm / year, respectively, and corrosion rate reduction rates of 70% and 73%, verifying the adaptability and economy of the technical solution within a wide parameter range. The performance degradation of the comparative examples fully demonstrates the rationality of the key parameter ranges of the ternary inhibitory composition. Comparative Example 13, lacking the B1-derived polymer microparticle intermediate I dispersion and relying solely on the binary system of aromatic amine component B2 and benzotriazole component B3, exhibited a corrosion rate as high as 0.055 mm / year and an acid value of 0.045 mg KOH / g, with a corrosion rate reduction rate of only 8%. Compared to Example 1, the corrosion protection efficiency decreased by 89%, directly demonstrating the irreplaceable role of polymer microparticles in interfacial selective enrichment and the ternary synergistic corrosion protection mechanism. Comparative Examples 1 and 2, due to excessively low (5 ppm) and excessively high (250 ppm) B1-derived polymer microparticle content respectively, resulted in insufficient corrosion protection efficiency and significantly deteriorated dispersion stability (increased particle size). The growth rates were 18.5% and 25.0%, respectively. Comparative Examples 3 to 10 had varying degrees of defects in interfacial adsorption capacity, passivation film density, mechanical stability, or dispersion uniformity due to polymer microparticle structure parameters exceeding the optimal range. The corrosion rates ranged from 0.025 to 0.048 mm / year, with a corrosion rate reduction rate of only 2058%, far lower than the 70-80% level of the Examples. Comparative Examples 11 and 12 had insufficient content of aromatic amine component B2 and benzotriazole component B3, resulting in severely weakened acid-catching and metal passivation capabilities. The acid values ​​were as high as 0.038 mg KOH / g and 0.029 mg KOH / g, respectively, which were 4.75 times and 3.63 times that of Example 1, significantly increasing the risk of long-term operation.Comprehensive data analysis shows that the ternary inhibition composition of the present invention, through the synergistic effect of ppm-level polymer microparticles and organic inhibitors, achieves a balance between strong extraction activity of highly polar extraction media and long-term equipment corrosion protection, high-dilution microstructure stability and long-term acid resistance without significantly changing the physical properties of the extractant. This provides a practical corrosion protection solution for the industrial application of sulfolane extraction systems.

[0100] Table 1 Summary of performance of examples and comparative examples

[0101]

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any equivalent structural transformations made under the concept of the present invention and using the contents of the specification and drawings of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A ternary inhibitory composition for sulfolane extractant, characterized in that the composition is based on sulfolane extractant A1, and the amount of each component is based on the mass of sulfolane extractant A1, the composition comprising: 1.1 Sulfolane-based extractant A1, comprising: (1) Sulfolane with a mass fraction of 95–99.0 wt%; (2) Water with a mass fraction of 1.0–5.0 wt%; (3) Azeotropic aromatic hydrocarbons with a mass fraction of 0–1.0 wt%; The sum of the mass fractions of components (1) to (3) is 100 wt%. 1.2 A B1-derived polymer microparticle intermediate I dispersion dispersed in the sulfolane-based extractant A1, with a polymer dry basis solids content of 10-200 ppm, wherein B1 represents a structural unit derived from heptadecenyl hydroxyethyl imidazoline, and the B1-derived polymer microparticle intermediate I dispersion is an oil-in-water polymer microparticle dispersion. 1.3 Aromatic amine component B2 used in amounts of 20–200 ppm; 1.4 Benzotriazole component B3 used in amounts of 50–200 ppm; 1.5 Optional additives in amounts of 0 to 50 ppm.

2. The ternary inhibitory composition of sulfolane-based extractant according to claim 1, wherein the polymer dry base of the B1-derived polymer microparticle intermediate I dispersion is composed of the following structural units: (1) B1 structural units with a molar fraction of 30-70 mol%, wherein the B1 structural units are derived from heptadecenylhydroxyethylimidazoline; (2) Benzotriazole structural unit C1 with a molar fraction of 5 to 30 mol%, wherein the benzotriazole structural unit C1 is derived from benzotriazole compounds; (3) Crosslinking structural units with a molar fraction of 5 to 30 mol%, wherein the crosslinking structural units are derived from at least one difunctional or multifunctional crosslinking agent; (4) Flexible segmental structural units with a mole fraction of 0–20 mol%, wherein, The sum of the mole fractions of the above structural units is 100 mol% The median particle size (D50) of the polymer microparticles in the B1-derived polymer microparticle intermediate I dispersion is 80–200 nm; and the acid neutralization equivalent of the B1-derived polymer microparticle intermediate I dispersion is not less than 2.0 mmol KOH / g on a dry polymer basis.

3. The ternary inhibitory composition of sulfolane extractant according to claim 1, characterized in that, The B1-derived polymer microparticle intermediate I dispersion is prepared by the following steps: A1. Preparation of the aqueous phase: Add 100 parts by mass of heptadecenylhydroxyethylimidazoline and 10-40 parts by mass of benzotriazole compounds to deionized water. After stirring and dissolving, adjust the pH of the aqueous phase to 7.0-9.5 with sodium hydroxide solution, and control the total mass fraction of heptadecenylhydroxyethylimidazoline and benzotriazole compounds to 5-30 wt% to obtain the aqueous phase. A2. Preparation of the organic continuous phase: To an organic phase comprising 300-800 parts by mass of sulfolane (based on 100 parts by mass of heptadecenylhydroxyethylimidazoline in step A1) and 0-200 parts by mass of n-heptane, add 5-50 parts by mass of the nonionic surfactant Triton X-100 (based on 100 parts by mass of heptadecenylhydroxyethylimidazoline in step A1), and stir until homogeneous to obtain the organic continuous phase; A3. The organic continuous phase is stirred at a temperature of 20–40°C, and the aqueous phase is added to the organic continuous phase at a substantially constant flow rate over 0.5–3.0 h to form a stable emulsion; A4. Under an inert atmosphere, the emulsion is heated to 40–80°C, and a crosslinking agent is added to the emulsion within 0.5–2.0 h. The total amount of the crosslinking agent added is 5–30 mol% relative to the molar number of the B1 structural unit. The crosslinking agent is selected from one or more of 1,4-butanediol diglycidyl ether, p-dichloromethylbenzene, and hexamethylene diisocyanate. A5. Cool the reaction system to 25-40°C, remove some of the n-heptane and water from the system under reduced pressure, remove the excess aqueous phase by phase separation, add sulfolane to adjust the solid content of the dispersion to 20-40 wt%, filter to remove large particles with a particle size greater than 1 μm, and fill under nitrogen protection to obtain the B1-derived polymer microparticle intermediate I dispersion.

4. The ternary inhibitory composition of sulfolane extractant according to claim 1, characterized in that, When the sulfolane extractant A1 contains an azeotropic aromatic hydrocarbon, the azeotropic aromatic hydrocarbon is selected from one or more of benzene, toluene, and xylene isomers; The aromatic amine component B2 is an aromatic amine acid scavenger, selected from one or both of diphenylamine and N-phenyl-1-naphthylamine; The benzotriazole component B3 is a metal passivating agent selected from one or more of benzotriazole, toluenetriazole and their soluble salts; The additives are selected from one or more of defoamers, flow improvers, and dispersion stabilizers.

5. The ternary inhibitory composition of sulfolane extractant according to claim 2, characterized in that, The flexible segmental structural units are derived from one or more of hydrophilic or hydrophobic diols, diamines, or polyethers.

6. The ternary inhibitory composition of sulfolane extractant according to claim 5, characterized in that, The flexible segmental structural unit is derived from one or more of polyethylene glycol 400, neopentyl glycol, and 1,6-hexanediol.

7. The ternary inhibitory composition of sulfolane extractant according to claim 1, characterized in that, After the ternary inhibitory composition of sulfolane extractant was used as an extractant and operated continuously in an industrial plant for 6 to 12 months, the acid value of the ternary inhibitory composition of sulfolane extractant was not higher than 0.01 mg KOH / g.

8. The ternary inhibitory composition of sulfolane extractant according to claim 1, characterized in that, The corrosion rate of carbon steel under simulated working conditions is no higher than 0.02 mm per year; compared with the control system under the same working conditions, which uses only sulfolane extractant A1 without adding B1 derivative polymer microparticle intermediate I dispersion, aromatic amine component B2 and benzotriazole component B3, the corrosion rate is reduced by no less than 70%.

9. A method for preparing a ternary inhibitory composition of sulfolane extractant according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Preparation of B1-derived polymer microparticle intermediate I dispersion with a solid content of 20-40 wt%; S2. Under conditions of 30-50°C, 100 parts by mass of the sulfolane extractant A1 are placed in a solvent tank equipped with a stirrer, and a metered amount of the B1-derived polymer microparticle intermediate I dispersion is added. Based on the sulfolane extractant A1, the concentration of the polymer dry solids is 10-200 ppm, and the mixture is stirred for 30-120 min to ensure that the B1-derived polymer microparticle intermediate I dispersion is uniformly dispersed in the sulfolane extractant A1. S3. Using a metering pump, add aromatic amine component B2 and benzotriazole component B3 to the system obtained in step S2. Based on sulfolane extractant A1, the dosage of aromatic amine component B2 is 20-200 ppm and the dosage of benzotriazole component B3 is 50-200 ppm. Continue stirring for 30-60 min at a temperature of 30-50°C to obtain a homogeneous sulfolane extractant ternary inhibitory composition. S4. The density, viscosity and conductivity of the sulfolane extractant ternary inhibitory composition obtained in step S3 are measured. When the above physical properties are stable, the sulfolane extractant ternary inhibitory composition is obtained.

10. The preparation method according to claim 9, characterized in that, In step S2 or step S3, an additional 5 to 50 ppm of the nonionic surfactant Triton X-100 is added as a dispersion stabilizer.

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