Amino acid-based multifunctional additive for efficient purification and resource utilization of raw coal gas and application thereof

Abstract

The application discloses an amino acid-based multifunctional additive for efficient purification and resource utilization of crude coal gas and application thereof. The additive realizes dual-function breakthrough through molecular synergistic design: the carboxyl and double hydroxyethyl provide strong hydrophilicity, the lauryl group strongly adsorbs asphaltene and polycyclic aromatic hydrocarbon, the tertiary amine group is protonated in alkaline ammonia water to neutralize the charge of oil droplets, the amide bond network forms hydrogen bond with tar, and the absorption rate of ammonia water to heavy tar is simultaneously improved and the emulsion layer demulsification is accelerated. The compound is stable in structure in an alkaline environment and is completely biodegradable. The compound replaces traditional complex additives with a single component, solves the contradiction between washing and separation in the purification of crude coal gas of Lurgi furnace, and the resource recovery rate is more than 95%. The optimal sample oil washing rate reaches 94.58%, the demulsification is completed in 19 minutes, and the oil-water separation rate reaches 99.58%.

Description

Technical Field

[0001] This invention belongs to the field of impurity absorption and oil-water separation technology after washing of crude coal gas. Specifically, it involves the preparation of a multifunctional amino acid derivative, N(α)-linear fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester, through multi-step synthesis based on L-lysine and z-branched fatty acids. This derivative is used as an auxiliary agent to promote the effective absorption of complex organic matter such as phenol, cresol, crude benzene, polycyclic aromatic hydrocarbons, asphaltenes, and dust impurities in crude coal gas generated by Lurgi furnace gasification by ammonia water, and to achieve oil-water separation of the water-in-oil emulsion layer after washing. The invention also relates to the preparation method and application of this auxiliary agent. Background Technology

[0002] The crude kerosene gas produced by Lurgi gasification contains not only major gases such as CO, H2, and CH4, but also complex organic compounds such as phenol, cresol, crude benzene, polycyclic aromatic hydrocarbons, and asphaltenes, along with a certain amount of dust. These impurities easily condense and adhere in subsequent cryogenic equipment and pipelines, leading to problems such as heat exchanger scaling and pipeline blockage. However, these impurities themselves have high recovery value; therefore, ammonia washing is used to purify the crude kerosene gas and utilize the impurities as resources.

[0003] During the washing process, light tars such as phenol and cresol can be effectively removed from crude coal gas by reacting with ammonia. However, asphaltenes in heavy tar have characteristics such as large molecular weight, high viscosity, high boiling point, and low volatility, making them difficult to remove using ammonia alone. More challenging is that asphaltenes molecules contain both hydrophilic groups such as hydroxyl and carboxyl groups, as well as long-chain hydrophobic alkyl groups, which tend to form relatively stable micelles or interfacial films in alkaline ammonia. This results in heavy tar in crude coal gas being "washed off," but subsequently difficult to "separate" from the aqueous phase.

[0004] To improve the absorption efficiency of asphaltenes and polycyclic aromatic hydrocarbons (PAHs), surfactants are typically added to ammonia water. These additives can reduce surface tension and regulate the hydrophilic-hydrophobic balance, thereby promoting the entry of impurities into the liquid phase. However, from a mechanistic perspective, this system presents several contradictions. First, structures that enhance the solubilization of tar and asphaltenes tend to more easily form an oil-in-water emulsion, making it difficult to separate the washed-off tar from the aqueous phase and weakening subsequent recovery efficiency. Second, since the washing medium is alkaline ammonia water, many conventional surfactants are easily hydrolyzed or deactivated under strongly alkaline conditions, making amines or special nonionic systems that are structurally stable in alkaline environments more suitable. Furthermore, while some traditional high-efficiency demulsifiers possess good demulsification capabilities, they are difficult to degrade, imposing a heavy burden on the environment and failing to meet the requirements of green development.

[0005] Traditional compound adjuvants have certain advantages. They can achieve multifunctional synergy by utilizing the complementary structures of different components, and their performance can be precisely controlled by adjusting the ratio. However, their disadvantages are also quite obvious: the formulations are complex, dosing and process control are difficult, batch stability and long-term operational consistency are poor, and safety and environmental assessment costs are higher. In contrast, single adjuvants have a clear composition and mechanism, are easier to scale up and control on-site, and their quality and efficacy are more stable. Summary of the Invention

[0006] To address the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a method for preparing a highly efficient and environmentally friendly additive that can promote the effective absorption of impurities in crude coal gas by ammonia water and achieve oil-water separation in an oil-in-water emulsion.

[0007] This invention synthesizes multifunctional modified lysine derivatives by grafting L-lysine, achieving high pH applicability while ensuring environmental friendliness, and realizing efficient cleaning of crude coal gas and efficient oil-water separation.

[0008] Another objective of this invention is to provide a highly efficient and environmentally friendly additive obtained by the above preparation method.

[0009] The purpose of this invention is to provide the application of the above-mentioned high-efficiency and environmentally friendly additive in crude coal gas absorption and oil-water separation.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a method for preparing a highly efficient and environmentally friendly additive, comprising the following steps:

[0012] (1) Dissolve L-lysine in an organic solvent, adjust the solution to alkaline, add ditert-butyl dicarbonate solution dropwise while stirring, react at room temperature, purify, and obtain N(α)-tert-butyloxycarbonyl-L-lysine;

[0013] (2) Dissolve N(α)-tert-butoxycarbonyl-L-lysine in an organic solvent, adjust the solution to alkaline, add benzyl bromide dropwise while stirring, react at room temperature, purify, and obtain N(α)-tert-butoxycarbonyl-L-lysine benzyl ester;

[0014] (3) N(α)-tert-butoxycarbonyl-L-lysine benzyl ester was dissolved in an organic solvent, and methyl acrylate was added dropwise under stirring at room temperature. The reaction was carried out and purified to obtain N(ε)-bis(2-methoxycarbonylethyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester.

[0015] (4) Dissolve N(ε)-bis(2-methoxycarbonylethyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester in an organic solvent, add propylene diamine, and heat to react to obtain N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine benzyl ester;

[0016] (5) N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)amino]carbamoyl]ethyl}]-L-lysine benzyl ester was dissolved in an organic solvent, the solution was adjusted to alkaline, and ethylene oxide gas was introduced under heating conditions to carry out the reaction. After purification, N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester was obtained;

[0017] (6) N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester was dissolved in an organic solvent, and trifluoroacetic acid was added dropwise under an ice-water bath. The reaction was carried out at room temperature and purified to obtain N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester;

[0018] (7) N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester was dissolved in an organic solvent, a straight-chain fatty acyl chloride was added, the solution was adjusted to alkalinity, the reaction was carried out, and the solution was purified to obtain N(α)-straight-chain fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester;

[0019] (8) N(α)-linear fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester was dissolved in an organic solvent, a catalyst was added, and the reaction was carried out under a hydrogen atmosphere and at room temperature. After purification, a multifunctional modified lysine derivative was obtained, which is a highly efficient and environmentally friendly additive.

[0020]

[0021] The structural formula of N(α)-myristoyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine

[0022] Preferably, in step (1), the molar ratio of L-lysine to ditert-butyl dicarbonate is 1:1.1-1.5.

[0023] Preferably, in step (1), alkalinity refers to a pH of 9-10.

[0024] Preferably, in step (1), the solution is adjusted to alkalinity using NaOH solution, wherein the concentration of the NaOH solution is 0.5-1 mol / L.

[0025] Preferably, in step (1), the temperature of L-lysine is an ice-water bath when adding the ditert-butyl dicarbonate solution.

[0026] Preferably, in step (1), the reaction is carried out at room temperature for 5-7 hours; the room temperature refers to 10-30℃.

[0027] Preferably, in step (1), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran, and methyl tert-butyl ether.

[0028] Preferably, in step (1), the ratio of L-lysine to organic solvent is 1g:30-80mL.

[0029] Preferably, in step (1), the concentration of the di-tert-butyl dicarbonate solution is 0.08-0.09 g / mL, and the solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran, and methyl tert-butyl ether.

[0030] Preferably, in step (2), the molar ratio of N(α)-tert-butoxycarbonyl-L-lysine to benzyl bromide is 1:1-1.5.

[0031] Preferably, in step (2), the alkalinity refers to a pH of 10.5-11.5.

[0032] Preferably, in step (2), NaOH solution is used to adjust the solution to alkalinity, and the concentration of the NaOH solution is 0.5-1 mol / L.

[0033] Preferably, in step (2), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran, and methyl tert-butyl ether.

[0034] Preferably, in step (2), the ratio of N(α)-tert-butoxycarbonyl-L-lysine to organic solvent is 1g:30-80mL.

[0035] Preferably, in step (2), the reaction is carried out at room temperature for 20-28 hours; the room temperature refers to 10-30℃.

[0036] Preferably, in step (3), the molar ratio of N(α)-tert-butoxycarbonyl-L-lysine benzyl ester to methyl acrylate is 1:2-4.

[0037] Preferably, in step (3), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran, and methyl tert-butyl ether.

[0038] Preferably, in step (3), the ratio of N(α)-tert-butoxycarbonyl-L-lysine benzyl ester to organic solvent is 1g:20-50mL.

[0039] Preferably, in step (3), room temperature refers to 10-30℃.

[0040] Preferably, in step (3), the reaction time is 20-28 hours.

[0041] Preferably, in step (4), the molar ratio of N(ε)-(2-methoxycarbonylpropyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester to propylene diamine is 1:2-5.

[0042] Preferably, in step (4), the organic solvent includes at least one of methanol, ethanol and acetonitrile.

[0043] Preferably, in step (4), the ratio of N(ε)-bis(2-methoxycarbonylethyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester to organic solvent is 1g:30-80mL.

[0044] Preferably, in step (4), the heating reaction temperature is 60-80℃ and the time is 8-12 hours.

[0045] Preferably, in step (5), the molar ratio of ethylene oxide to N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine benzyl ester is 1-5:1.

[0046] Preferably, in step (5), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran, and methyl tert-butyl ether.

[0047] Preferably, in step (5), the ratio of N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine benzyl ester to organic solvent is 1g:20-50mL.

[0048] Preferably, in step (5), alkalinity refers to a pH of 9-10.

[0049] Preferably, in step (5), NaOH solution is used to adjust the solution to alkalinity, and the concentration of the NaOH solution is 0.5-1 mol / L.

[0050] Preferably, in step (5), the heating temperature is 50-70℃.

[0051] Preferably, in step (5), the reaction time is 4-6 hours.

[0052] Preferably, in step (6), the amount of trifluoroacetic acid used is 5-15 times the mass of N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester.

[0053] Preferably, in step (6), the organic solvent includes at least one of methanol, ethanol and acetonitrile.

[0054] Preferably, in step (6), the ratio of N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester to organic solvent is 1g:10-30mL.

[0055] Preferably, in step (6), room temperature refers to 10-30℃.

[0056] Preferably, in step (6), the temperature of the N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester solution is an ice-water bath when trifluoroacetic acid is added dropwise.

[0057] Preferably, in step (6), the reaction time at room temperature is 2-4 hours.

[0058] Preferably, in step (7), the molar ratio of linear fatty acyl chloride to N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester is 1.05-1.5:1.

[0059] Preferably, in step (7), the linear fatty acyl chloride has 12-18 alkyl groups.

[0060] More preferably, the linear fatty acyl chloride is at least one of myristoyl chloride, lauroyl chloride, palmitoyl chloride, stearoyl chloride, and cocoyl chloride.

[0061] Preferably, in step (7), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran, and methyl tert-butyl ether.

[0062] Preferably, in step (7), the ratio of N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester to organic solvent is 1g:30-60mL.

[0063] Preferably, in step (7), alkalinity refers to a pH of 8-9.

[0064] Preferably, in step (7), NaOH solution is used to adjust the solution to alkalinity, and the concentration of the NaOH solution is 0.5-1 mol / L.

[0065] Preferably, in step (7), the reaction temperature is room temperature and the time is 4-6 hours; the room temperature refers to 10-30℃.

[0066] Preferably, in step (8), the amount of catalyst used is 5-10% of the mass of N(α)-linear fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester.

[0067] Preferably, in step (8), the catalyst is Pd / C; more preferably, it is 10wt% Pd-C.

[0068] Preferably, in step (8), the organic solvent includes at least one of methanol, ethanol and acetonitrile.

[0069] Preferably, in step (8), the ratio of N(α)-linear fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester to organic solvent is 1g:40-80mL.

[0070] Preferably, in step (8), room temperature refers to 10-30℃.

[0071] Preferably, in step (8), the reaction time is 10-14 hours.

[0072] Secondly, the present invention provides a highly efficient and environmentally friendly additive obtained by the above preparation method.

[0073] Thirdly, the present invention provides the application of the above-mentioned high-efficiency and environmentally friendly additive in crude coal gas absorption and oil-water separation.

[0074] The high-efficiency and environmentally friendly additives described in this invention promote the absorption of impurities such as phenol, cresol, asphaltenes, polycyclic aromatic hydrocarbons, coarse benzene, and dust by ammonia water and achieve oil-water separation in the water-in-oil emulsion layer.

[0075] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0076] L-Lysine is environmentally friendly, and lysine and fatty acids are widely available as biological products. Surfactant auxiliaries developed based on these can reduce potential environmental hazards at the source. This invention utilizes a precisely designed and synthesized multifunctional amino acid derivative, N(α)-linear fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine, to construct an innovative structure with both environmental friendliness and synergistic effects of multiple functional groups through eight controllable modifications: the carboxylic acid and bis(hydroxyethyl) in the molecule provide strong hydrophilicity; the long-chain fatty acyl group strongly adsorbs heavy tar components such as asphaltenes and polycyclic aromatic hydrocarbons through hydrophobic interactions; the tertiary amine group (aminoethylcarbamoylethyl) is protonated in alkaline ammonia water, neutralizing the negative charge on the oil droplet surface; the amide bond acts as a hydrogen bond donor and acceptor, forming a molecular network with the polar groups of tar. This synergistic effect enables the auxiliary to simultaneously achieve solubilization, washing, and demulsification separation. Detailed Implementation

[0077] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0078] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available conventional products.

[0079] Example 1

[0080] (1) Dissolve 1 g of L-lysine in 50 mL of anhydrous tetrahydrofuran (THF), cool and stir in an ice-water bath. Slowly add 1 mol / L NaOH aqueous solution to adjust the pH of the solution to 10. In another container, dissolve 1.67 g of di-tert-butyl dicarbonate in 20 mL of anhydrous THF to prepare a solution. While stirring, slowly add the (Boc)₂O / THF solution to the cooled L-lysine / THF solution. After the addition is complete, remove the ice bath and continue stirring at room temperature for 6 hours. The reaction progress can be monitored by TLC. After the reaction is complete, add an appropriate amount of HCl to the reaction solution to acidify to pH≈3-4. Extract the aqueous phase three times with ethyl acetate and combine the organic phases. Wash the organic phase with saturated brine and dry with anhydrous Na₂SO₄. Filter to remove Na₂SO₄, wash the filter cake and container with a small amount of ethyl acetate, and combine the filtrates. Concentrate under reduced pressure using a rotary evaporator to remove the solvent, and obtain the white solid product N(α)-tert-butyloxycarbonyl-L-lysine.

[0081] (2) Dissolve 1.5 g of N(α)-tert-butoxycarbonyl-L-lysine in 50 mL of anhydrous THF. Add 1 mol / L NaOH aqueous solution dropwise to adjust the pH of the solution to 11. Slowly add 1.09 g of benzyl bromide dropwise while stirring. Stir the reaction at room temperature for 24 hours, and monitor the reaction progress by TLC. Purification is performed as above. The solid product N(α)-tert-butoxycarbonyl-L-lysine benzyl ester is obtained.

[0082] (3) Dissolve 1.87 g of N(α)-tert-butoxycarbonyl-L-lysine benzyl ester in 7 mL of anhydrous THF and stir at room temperature. While stirring, slowly add 1.3 g of methyl acrylate dropwise. React at room temperature for 24 hours with stirring, and monitor the reaction progress by TLC. The purification process is the same as above. The product N(ε)-bis(2-methoxycarbonylethyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester is obtained.

[0083] (4) Dissolve 2.0 g of the product N(ε)-(2-methoxycarbonylpropyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester in 100 mL of methanol. Add 1.25 g of propylenediamine. Heat the reaction system to 70 °C and stir for 10 hours. The reaction progress can be monitored by TLC. The product N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}-L-lysine benzyl ester is obtained.

[0084] (5) Dissolve 1.4 g of N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)amino]carbamoyl]ethyl}]-L-lysine benzyl ester in 50 mL of anhydrous THF. Adjust the pH to 10 by adding 1 mol / L NaOH aqueous solution. Heat the reaction system to 60 °C. While stirring, slowly introduce ethylene oxide gas into the reaction solution at a flow rate of 3 mL / min for 60 min, maintaining the temperature at 60 °C during the gas introduction process. After the gas introduction is completed, continue stirring the reaction at 60 °C for 5 hours. The reaction progress can be monitored by TLC. The product N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester is obtained.

[0085] (6) Dissolve 1.5 g of the product N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester in 30 mL of methanol. Cool the reaction flask in an ice-water bath. Slowly add 3.5 mL of trifluoroacetic acid. After the addition is complete, remove the ice bath and stir the reaction at room temperature for 3 hours. The deprotection process can be monitored by TLC. The deprotected product N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester is obtained.

[0086] (7) Dissolve 1.0 g of N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester in 40 mL of anhydrous THF and stir at room temperature. Add 0.52 g of myristoyl chloride and stir until homogeneous. Add 1 mol / L NaOH aqueous solution dropwise under ice bath to adjust and maintain the pH of the reaction solution at 9. Stir the reaction at room temperature for 6 hours, and monitor the reaction progress by TLC. After the reaction is complete, add an appropriate amount of water to quench. Filter, concentrate, and purify the residue by silica gel column chromatography to obtain the product N(α)-myristoyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester.

[0087] (8) Dissolve 0.7 g of the product N(α)-myristoyl-N(ε)-(2-aminoethylcarbamoylethyl)-N''-bis(2-hydroxyethyl)-L-lysine benzyl ester in 50 mL of methanol. Add 0.7 g of 10 wt% Pd-C catalyst. Place the reaction system under a hydrogen atmosphere (1 atm) and stir at room temperature for 12 hours. The completion of benzylation can be monitored by TLC. After the reaction is complete, remove the Pd-C catalyst by diatomaceous earth filtration and wash the filter cake thoroughly with methanol. Filter and purify to obtain the final target product N(α)-myristoyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine.

[0088] The final product, N(α)-myristoyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine, was characterized using Fourier transform infrared spectroscopy. The spectroscopy results were obtained at ~3300 cm⁻¹. -1 A broad peak appears nearby (OH and NH stretching vibrations). At ~2850-2900 cm⁻¹ -1 A strong peak appears (CH stretching vibration, originating from the myristoyl long chain). At ~1630-1650 cm⁻¹ -1(Amide I band, C=O stretching vibration) and ~1540-1580cm -1 A characteristic absorption peak appears (amide II band, NH bending vibration). At ~1050 cm⁻¹ -1 A peak appears nearby (CO stretching vibration, from hydroxyethyl). The product from step 6, N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester, shows a primary amine NH bending vibration peak (~1600 cm⁻¹). -1 (near) and stretching vibration peak (~3300-3500cm) -1 In step 7, the peak of the product N(α)-myristoyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester disappears, and the peak at ~1650 cm⁻¹ disappears. -1 A new amide carbonyl peak appears nearby. After debenzylation in step 8, an ester carbonyl peak (~1730 cm⁻¹) should be observed. -1 The peak of the carboxylic acid carbonyl group (near) disappears, and the peak of the carboxylic acid carbonyl group (~1700-1720cm) disappears. -1 )Appear.

[0089] According to step (5), by adjusting the ratio of N(α)-tert-butoxycarbonyl-N(ε)-(2-aminoethylcarbamoylethyl)-L-lysine benzyl ester and ethylene oxide, amino acid derivatives with different numbers of hydroxyethyl groups with straight-chain fatty acyl groups can be synthesized. The samples are numbered 1#, 2# and 3#.

[0090] According to step (7), lauroyl chloride (C=12), palmitoyl chloride (C=16) and stearoyl chloride (C=18) are used instead of myristoyl chloride to finally synthesize amino acid derivative samples with different straight-chain fatty acyl groups. The sample numbers are 4#, 5# and 6#.

[0091] Weigh 5g of each of the above samples and slowly add them to 45g of deionized water. Maintain the temperature at 40-50℃ and stir until the polymer dissolves to obtain 5wt% additive solutions corresponding to different samples.

[0092] Table 1

[0093]

[0094] Example 2

[0095] Asphaltene and ethylbenzene were thoroughly mixed at a mass ratio of 1:4 to ensure complete incorporation of the asphaltene into the ethylbenzene. The prepared solution was then vaporized at 300°C using a liquid pump at a flow rate of 0.5 mL / min through a heating pipe. The vaporized asphaltene / ethylbenzene mixture was then mixed with nitrogen gas at a flow rate of 150 mL / min and introduced into a three-necked flask containing 200 mL of 5 wt% additive solution. After 4 hours of continuous influx, the pump was stopped. The liquid in the three-necked flask was transferred to a separatory funnel to separate the oil and water phases. The volume of the oil phase was measured using a graduated cylinder, and the contents of asphaltene and ethylbenzene in the aqueous phase were determined using liquid chromatography. The volumes of ethylbenzene and asphaltene in the oil and water phases were added together and compared with the total influx volume to obtain the oil washing rate. The table below shows the gas washing results for each sample.

[0096] Table 2

[0097]

[0098] Example 3

[0099] Emulsion preparation: Weigh 5g of asphalt sample oil and 20g of ethylbenzene into a 100ml flask, and stir in a 40℃ water bath until completely mixed to obtain a composite oil phase. Place this composite oil phase with 475.0g of dilute NaOH aqueous solution (pH=9) in a container, and strongly disperse it for 5min at 30000r / min using a high-shear emulsifier to obtain an O / W type emulsion with a total oil phase mass fraction of 5.0% (of which asphalt accounts for 1.0% and ethylbenzene accounts for 4.0%). Transfer the emulsion to a plastic tube for later use. After standing at room temperature for 24h, no significant phase separation was observed in the prepared emulsion.

[0100] After adding 10g of the above 5wt% auxiliary agent solution to the emulsion prepared above, shake the colorimetric tube thoroughly 200 times, let it stand for 30 minutes, and then use a long-tipped syringe to draw 10mL of the demulsified aqueous solution. Use a liquid chromatograph to test the oil content in the demulsified aqueous solution. The demulsification efficiency can be obtained by dividing the amount of oil remaining in the water by the amount of oil in the original sample.

[0101] Table 3

[0102]

[0103] 1. With myristoyl chloride as the constant ingredient, changing the ratio of N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine benzyl ester and ethylene oxide affects the wash rate, demulsification efficiency, and oil-water phase separation time. The optimal wash rate (94.58%) was achieved when the molar ratio was 1:4 (sample #2). Excessive ethylene oxide (1:6, sample #3) or insufficient ethylene oxide (1:2, sample #1) reduced the wash rate. Regarding demulsification efficiency, sample #2 achieved the highest at 99.58%, with the order being 2# > 3# > 1#. The oil-water phase separation time for sample #2 was only 19 minutes, while for sample #3, due to an excessive number of hydroxyethyl groups resulting in a thicker micelle hydration layer, the separation time was delayed to 36 minutes.

[0104] With a fixed molar ratio of N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine benzyl ester and ethylene oxide of 1:4, changing the type of alkyl acyl chloride affects the wash rate and demulsification performance. As the carbon chain length of the alkyl acyl chloride increases, the wash rate gradually increases, from lauroyl chloride (sample 4#, wash rate 82.17%) to stearoyl chloride (sample 6#, wash rate 91.08%). During demulsification, the longer the carbon chain, the faster the oil-water separation; the oil-water phase separation time for sample 4# is 41 min, while for sample 6# it only requires 28 min.

[0105] Considering both oil washing and demulsification performance, sample #2 (C14 chain + n=4 hydroxyethyl groups) performed best. Its oil washing rate reached 94.58%; its demulsification efficiency was 99.58%, and its oil-water phase separation time was only 19 minutes. This is because the C14 chain provides moderate hydrophobicity, and the n=4 hydroxyethyl group optimizes the hydrophilic-hydrophobic balance.

[0106] Comparative Example 1

[0107] The N(ε)-bis(2-methoxycarbonylethyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester obtained in step (3) of Example 1, the N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine benzyl ester obtained in step (4), and the N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)]]-L-lysine benzyl ester obtained in step (5) are compared. [2-(3-(3-aminopropyl)aminopropyl)carbamoyl)ethyl]}-L-lysine benzyl ester was de-steryloxycarbonyl and benzyl ester to obtain N(ε)-bis(2-methoxycarbonylethyl)-L-lysine, N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine, and N(ε)-bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine. L-lysine and the above three substances were prepared into 5 wt% auxiliary solutions according to the method described in Example 1, and labeled A, B, C, and D, respectively. E is a pure water sample.

[0108] The above-mentioned compound additive samples were tested for their oil-water separation capacity and absorption capacity according to the methods shown in Examples 2 and 3. The results are shown in the table below.

[0109] Table 4

[0110]

[0111] Table 5

[0112]

[0113] Conclusion: 1. Comparison between sample A and sample E shows that L-lysine has no absorption or demulsification ability.

[0114] 2. Derivatives containing only partial groups have significantly lower wash rates and demulsification efficiency than #2. The synergistic effect of the N(α)-linear fatty acyl hydrophobic chain with hydrophilic groups such as amide and hydroxyl groups is irreplaceable.

[0115] Comparative Example 2

[0116] The preparation process is the same as in Example 1, except that in step (7), myristoyl chloride is replaced with heptanoyl chloride (C=7). Finally, an amino acid derivative sample containing heptanoyl group can be synthesized, and the sample number is S1.

[0117] The preparation process of Example 1 is similar, except that in step (7), myristoyl chloride is replaced with octanoyl chloride (C=8), and finally an amino acid derivative sample containing octanoyl group can be synthesized, the sample number is S2.

[0118] The preparation process of Example 1 is similar, except that in step (7), myristoyl chloride is replaced with nonanoyl chloride (C=9), and finally an amino acid derivative sample containing nonanoyl group can be synthesized, the sample number is S3.

[0119] The preparation process of Example 1 is similar, except that in step (7), myristoyl chloride is replaced with eicosanoyl chloride, and finally an amino acid derivative sample containing eicosanoyl group can be synthesized, the sample number being S4.

[0120] The preparation process of Example 1 is similar, except that in step (7), myristoyl chloride is replaced with docosanoyl chloride, and finally an amino acid derivative sample containing docosanoyl group can be synthesized, the sample number is S5.

[0121] The above five substances were prepared into a 5 wt% auxiliary solution according to the method described in Example 1.

[0122] The above-mentioned additive samples were tested for their oil-water separation ability and absorption ability according to the methods shown in Examples 2 and 3. The test results are shown in the table below.

[0123] Table 6

[0124]

[0125] Table 7

[0126]

[0127] From the data in the table, we can obtain:

[0128] 1. The wash rate of S1-S3 increases gradually, the oil-water separation time gradually decreases, and the demulsification efficiency gradually increases. Comparing the performance of the samples in Examples 2 and 3, because the hydrophobic chains of S1-S3 are too short, the adsorption force on asphaltenes / polycyclic aromatic hydrocarbons is insufficient, relying only on hydrogen bonding and electrostatic interactions, resulting in insufficient wash rate, low demulsification efficiency, and overall performance that does not meet the standards.

[0129] 2. The wash rate of S4-S5 drops drastically, the separation time is >180 min, and the demulsification efficiency is low. The ultra-long chain causes molecular coiling, which masks the amide bond and tertiary amine group, weakens the hydrophilic-tar interaction, and hinders oil droplet aggregation, resulting in a double collapse in both wash rate and demulsification efficiency.

[0130] Comparative Example 3

[0131] The preparation process of Example 1 is the same as that of Example 1, except that steps (3)-(4) are omitted. N(α)-tert-butoxycarbonyl-L-lysine benzyl ester is reacted directly with ethylene oxide and then fatty acylated to obtain amino acid derivative sample X1 with only hydroxyethyl without the branched topology constructed by chain extension of methyl acrylate and propylene diamine.

[0132] The preparation process of Example 1 is similar, except that in step (3), the molar ratio of N(α)-tert-butoxycarbonyl-L-lysine benzyl ester to methyl acrylate is 1:1 (others are the same as 2#), resulting in amino acid derivative sample X2 with insufficient branching.

[0133] The preparation process of Example 1 is the same as that of Example 1, except that the ratio of ethylene oxide in step (5) is increased to 1:8 (other aspects are the same as 2#) to obtain sample X3 with excessive hydroxyethylation.

[0134] The above five substances were prepared into a 5 wt% auxiliary solution according to the method described in Example 1.

[0135] The above-mentioned additive samples were tested for their oil-water separation ability and absorption ability according to the methods shown in Examples 2 and 3. The test results are shown in the table below.

[0136] Table 8

[0137]

[0138] Table 9

[0139]

[0140] From the data in the table, we can obtain:

[0141] Sample X1 skipped the methyl acrylate addition and propylenediamine chain extension steps, resulting in a molecule containing only hydroxyethyl side chains. This led to a significant increase in oil-water separation time to 96 minutes (compared to 19 minutes in Example 2), a sharp drop in demulsification efficiency to 39.66%, and an oil washing rate of only 54.00%. This indicates that a multi-branched topology is a core element in constructing a highly efficient demulsifier, enhancing interfacial adsorption and oil droplet coalescence capabilities through a three-dimensional spatial network. Linear structures, lacking this characteristic, suffer from performance degradation.

[0142] Although sample X2 (methyl acrylate molar ratio 1:1) had a better demulsification efficiency (82.66%) than X1, its oil washing rate (71.92%) was still 22.66% lower than that of Example 1. Insufficient branching (half the amount of methyl acrylate) reduced the rigidity of the molecular chain and decreased the interfacial adsorption density, resulting in limited oil phase recovery.

[0143] Sample X3 (1:8 over-hydroxyethylation): Although its demulsification efficiency (76.22%) and wash-off rate (63.58%) were better than X1, they were still significantly lower than those of Example 2 (99.58% and 94.58%, respectively). Over-hydroxyethylation resulted in excessively large molecular sizes, steric hindrance hindering its penetration to the oil-water interface, and weakening molecular flexibility, thus reducing the ability to regulate dynamic surface tension. This result verifies that a hydroxyethylation molar ratio of 1:4-1:6 is the optimal range (conclusion of Example 3), and exceeding this range will lead to performance degradation due to branching imbalance.

[0144] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a highly efficient and environmentally friendly additive, characterized in that, Includes the following steps: (1) Dissolve L-lysine in an organic solvent, adjust the solution to alkaline, add ditert-butyl dicarbonate solution dropwise while stirring, react at room temperature, purify, and obtain N(α)-tert-butyloxycarbonyl-L-lysine; (2) Dissolve N(α)-tert-butoxycarbonyl-L-lysine in an organic solvent, adjust the solution to alkaline, add benzyl bromide dropwise while stirring, react at room temperature, purify, and obtain N(α)-tert-butoxycarbonyl-L-lysine benzyl ester; (3) N(α)-tert-butoxycarbonyl-L-lysine benzyl ester was dissolved in an organic solvent, and methyl acrylate was added dropwise under stirring at room temperature. The reaction was carried out and purified to obtain N(ε)-bis(2-methoxycarbonylethyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester. (4) Dissolve N(ε)-bis(2-methoxycarbonylethyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester in an organic solvent, add propylene diamine, and heat to react to obtain N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine benzyl ester; (5) N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)amino]carbamoyl]ethyl}]-L-lysine benzyl ester was dissolved in an organic solvent, the solution was adjusted to alkaline, and ethylene oxide gas was introduced under heating conditions to carry out the reaction. After purification, N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester was obtained; (6) N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester was dissolved in an organic solvent, and trifluoroacetic acid was added dropwise under an ice-water bath. The reaction was carried out at room temperature and purified to obtain N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester; (7) N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester was dissolved in an organic solvent, a straight-chain fatty acyl chloride was added, the solution was adjusted to alkalinity, the reaction was carried out, and the solution was purified to obtain N(α)-straight-chain fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester; (8) N(α)-linear fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester was dissolved in an organic solvent, a catalyst was added, and the reaction was carried out under a hydrogen atmosphere and at room temperature. After purification, a multifunctional modified lysine derivative was obtained, which is a highly efficient and environmentally friendly additive. In step (7), the straight-chain fatty acyl chloride has 12-18 alkyl carbon atoms.

2. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of L-lysine to ditert-butyl dicarbonate is 1:1.1-1.5; And / or, in step (2), the molar ratio of N(α)-tert-butoxycarbonyl-L-lysine to benzyl bromide is 1:1-1.5; And / or, in step (3), the molar ratio of N(α)-tert-butoxycarbonyl-L-lysine benzyl ester to methyl acrylate is 1:2-4; And / or, in step (4), the molar ratio of N(ε)-bis(2-methoxycarbonylethyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester to propylene diamine is 1:2-5; And / or, in step (5), the molar ratio of ethylene oxide to N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine benzyl ester is 1-5:1; And / or, in step (6), the amount of trifluoroacetic acid used is 5-15 times the mass of N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester; And / or, in step (7), the molar ratio of linear fatty acyl chloride to N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester is 1.05-1.5:1; And / or, in step (8), the amount of catalyst used is 5-10% of the mass of N(α)-linear fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester.

3. As described in claim 1 or 2, characterized in that, In step (8), the catalyst is Pd / C.

4. As described in claim 3, characterized in that, In step (7), the linear fatty acyl chloride is at least one of myristoyl chloride, lauroyl chloride, palmitoyl chloride, stearoyl chloride, and cocoyl chloride; And / or, in step (8), the catalyst is 10 wt% Pd-C.

5. As described in claim 1 or 2, characterized in that, In step (1), alkalinity refers to a pH of 9-10; And / or, in step (2), the alkalinity refers to a pH of 10.5-11.5; And / or, in step (5), alkalinity refers to a pH of 9-10; And / or, in step (7), alkalinity refers to a pH of 8-9.

6. As described in claim 1 or 2, characterized in that, In step (1), the reaction is carried out at room temperature for 5-7 hours; the room temperature refers to 10-30℃. And / or, in step (2), the reaction is carried out at room temperature for 20-28 hours; the room temperature refers to 10-30°C; And / or, in step (3), room temperature refers to 10-30℃; And / or, in step (3), the reaction time is 20-28 hours; And / or, in step (4), the temperature of the heating reaction is 60-80℃ and the time is 8-12 hours; And / or, in step (5), the heating temperature is 50-70℃; And / or, in step (5), the reaction time is 4-6 hours; And / or, in step (6), room temperature refers to 10-30℃; And / or, in step (6), the reaction time at room temperature is 2-4 hours; And / or, in step (7), the reaction temperature is room temperature and the time is 4-6 hours; the room temperature refers to 10-30℃; And / or, in step (8), room temperature refers to 10-30℃; And / or, in step (8), the reaction time is 10-14 hours.

7. As described in claim 1 or 2, characterized in that, In step (1), the temperature of L-lysine is an ice-water bath when adding the di-tert-butyl dicarbonate solution; And / or, in step (6), when adding trifluoroacetic acid, the temperature of the N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester solution is in an ice-water bath.

8. As described in claim 1 or 2, characterized in that, In step (1), the solution is adjusted to alkalinity using NaOH solution, the concentration of which is 0.5-1 mol / L; And / or, in step (1), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran and methyl tert-butyl ether; And / or, in step (1), the ratio of L-lysine to organic solvent is 1g: 30-80mL; And / or, in step (1), the concentration of the ditert-butyl dicarbonate solution is 0.08-0.09 g / mL, and the solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran and methyl tert-butyl ether; And / or, in step (2), the solution is adjusted to alkalinity using NaOH solution, wherein the concentration of the NaOH solution is 0.5-1 mol / L; And / or, in step (2), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran and methyl tert-butyl ether; And / or, in step (2), the ratio of N(α)-tert-butoxycarbonyl-L-lysine to organic solvent is 1 g: 30-80 mL; And / or, in step (3), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran and methyl tert-butyl ether; And / or, in step (3), the ratio of N(α)-tert-butoxycarbonyl-L-lysine benzyl ester to organic solvent is 1 g: 20-50 mL; And / or, in step (4), the organic solvent includes at least one of methanol, ethanol and acetonitrile; And / or, in step (4), the ratio of N(ε)-bis(2-methoxycarbonylethyl)-N(α)-tert-butoxycarbonyl-L-lysine benzyl ester to organic solvent is 1 g: 30-80 mL; And / or, in step (5), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran and methyl tert-butyl ether; And / or, in step (5), the ratio of N(α)-tert-butoxycarbonyl-N(ε)-bis{2-[3-(3-aminopropyl)carbamoyl]ethyl}]-L-lysine benzyl ester to organic solvent is 1 g: 20-50 mL; And / or, in step (5), the solution is adjusted to alkalinity using NaOH solution, wherein the concentration of the NaOH solution is 0.5-1 mol / L; And / or, in step (6), the organic solvent includes at least one of methanol, ethanol and acetonitrile; And / or, in step (6), the ratio of N(α)-(tert-butoxycarbonyl)-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester to organic solvent is 1 g: 10-30 mL; And / or, in step (7), the organic solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran and methyl tert-butyl ether; And / or, in step (7), the ratio of N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester to organic solvent is 1 g: 30-60 mL; And / or, in step (7), the solution is adjusted to alkalinity using NaOH solution, wherein the concentration of the NaOH solution is 0.5-1 mol / L; And / or, in step (8), the organic solvent includes at least one of methanol, ethanol and acetonitrile; And / or, in step (8), the ratio of N(α)-linear fatty acyl-N(ε)-{bis[2-(3-{3-[bis(2-hydroxyethyl)amino]propyl}carbamoyl)ethyl]}-L-lysine benzyl ester to organic solvent is 1 g: 40-80 mL.

9. A highly efficient and environmentally friendly additive prepared by the preparation method according to any one of claims 1-8.

10. The application of the high-efficiency and environmentally friendly additive as described in claim 9 in crude coal gas absorption and oil-water separation.

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