A comb copolymer dispersant butter inhibitor

Abstract

The present invention discloses a comb-type copolymer dispersant butter inhibitor, belonging to the field of chemical technology. In response to the technical problem that butter is easily produced but difficult to disperse and discharge from the caustic washing tower during the cracking process for preparing ethylene, thus affecting production, the invention provides a comb-type copolymer into which structures such as DOTA, phenolic hydroxyl groups, and benzene rings are introduced, which can prevent the polymerization reaction from producing butter through antioxidant properties, chelating metal ions, and similar compatibility. A butter inhibitor is also provided, comprising: an inhibitor, an antioxidant, a comb-type copolymer, a surfactant, and a solvent. This can effectively reduce the production of butter and promote its dispersion and discharge from the caustic washing tower, thereby achieving the technical effect of effectively reducing the pressure difference.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, in particular to a comb-type copolymer dispersant butter inhibitor. Background Art

[0002] During the cracking process to produce ethylene, a large amount of acidic gases such as H2S and CO2 are produced, which need to go through an alkaline washing process. During the alkaline washing process, the cracked gas will produce polymers. These polymers are liquid and easily form a yellow viscous state when in contact with air. They are usually called "butter", which will seriously affect the normal operation and alkaline washing effect of the alkaline washing tower and consume a large amount of alkaline solution. At the same time, a large amount of butter is easy to polymerize and scale to clog the distributor and packing in the tower, causing tower blockage and shortening the operation cycle of the alkaline washing tower.

[0003] The mechanisms of butter formation include:

[0004] 1. During the alkali washing process of cracked gas, dienes or other unsaturated hydrocarbons are easily formed into free radicals under the action of trace oxygen and metal ions, which then initiate the formation of cross-linked polymers;

[0005] 2. Aldehydes or ketones in the cracking gas cause aldol condensation or aldol condensation reaction under the action of alkali, that is, aldehydes or ketones with active hydrogen atoms on the α-position carbon atoms of two molecules can undergo addition reaction under the action of alkali to generate β-carbonyl aldehydes, which are further added to polymers of a certain molecular weight.

[0006] Prior art CN110294662A provides a butter inhibitor consisting of a mixture of diethylhydroxylamine, imidazoline, and ammonium dihydrogen phosphate. This inhibitor utilizes imidazoline adsorption on the walls of the alkali-washing tower to form a protective film, effectively inhibiting free radical polymerization. However, this method still uses a large amount of inhibitor and fails to effectively improve the dispersibility of butter.

[0007] Prior art CN118108567A discloses a butter inhibitor for an MTO caustic washing tower, comprising the following components in percentage by mass: diethylhydroxylamine, ammonium dihydrogen phosphate, sodium gluconate, hydroxylamine sulfate, phytate, quaternized polyethyleneimine, guanidinated polyethyleneimine, DMF, carbohydrazide, and water. According to experimental data, although the above method can effectively reduce polymer production, it is still difficult to increase the dispersibility of the butter, which is not conducive to the discharge of the generated butter and still increases the pressure difference.

[0008] The accumulation of butter in the alkali solution can easily cause blockage of the alkali washing tower, and in severe cases, cause the device to stop operating. Therefore, in view of the technical problems existing in the existing technology, it is still urgent to develop a more effective butter inhibitor. Summary of the Invention

[0009] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides a comb copolymer dispersant butter inhibitor.

[0010] The technical solutions for achieving the purpose of the present invention are as follows:

[0011] A comb copolymer dispersant, characterized in that it has the following structural formula (I):

[0012] (I), m and n are selected from any integers of 5-100, and the molar ratio of monomers A, B, and C for preparing the copolymer is x:y:z=(4-7):(3-5):(3-8).

[0013] The preparation method of the copolymer of formula (I) is:

[0014] S1: Synthesis of monomer A:

[0015] Under nitrogen atmosphere, 3,4-dihydroxymandelic acid was dissolved in anhydrous DMF (N,N-dimethylformamide) solvent, and EDC and NHS were added in sequence, and stirred for activation to obtain a 3,4-dihydroxymandelic acid activated solution;

[0016] The activated 3,4-dihydroxymandelic acid solution was added dropwise to the polyethylene glycol diamine (H2N-PEGm-NH2) solution, stirred, and reacted fully to obtain a 3,4-dihydroxymandelic acid-modified polyethylene glycol compound;

[0017] Acrylic acid was dissolved in a phosphate buffer solution of pH 5.5, and EDC and NHS were added. The mixture was stirred at room temperature for 1 hour to fully activate the carboxyl groups of acrylic acid to form an acrylic acid carboxyl group activated solution.

[0018] The polyethylene glycol compound modified with 3,4-dihydroxymandelic acid is dissolved in a phosphate buffer solution at pH 5.5, and the acrylic acid carboxyl activation solution is added thereto, and the mixture is stirred to fully react, thereby obtaining monomer A.

[0019] The molar ratio of 3,4-dihydroxymandelic acid, polyethylene glycol diamine and acrylic acid is (1-1.1): (1-1.05): (0.95-1).

[0020] S2: Synthesis of monomer B:

[0021] Dissolve polyethylene glycol diamine (NH2-PEGn-NH2) in phosphate buffer, add DOTA-NHS ester solution dropwise under stirring, and stir thoroughly to react to obtain DOTA-PEG-NH2 solution;

[0022] Dissolve acrylic acid in phosphate buffer at pH 5.5, add EDC and NHS, and stir at room temperature for 1 hour to fully activate the carboxyl groups of acrylic acid to form an acrylic acid carboxyl group activated solution;

[0023] The acrylic acid carboxyl activation solution was added dropwise to the DOTA-PEG-NH2 solution, and the mixture was stirred thoroughly to react to obtain monomer B.

[0024] The molar ratio of DOTA-NHS, polyethylene glycol diamine, and acrylic acid is (1-1.1): (1-1.05): (1-0.95).

[0025] S3: Under nitrogen atmosphere, monomer A, monomer B, and monomer C were dissolved in isopropanol solution, heated with stirring, and the temperature was raised to 85°C. 2,2'-azobis(2-methylbutyronitrile) was dissolved in isopropanol and added to the reaction system, and the reaction was carried out for 4 hours. Subsequently, the initiator 2,2'-azobis(2-methylbutyronitrile) was added, and the reaction was continued for 4 hours. The reaction was stopped, the solution was purified by dialysis, and the solution was freeze-dried. The molar ratio of monomer A, monomer B, and monomer C was (4-7): (3-5): (3-8).

[0026] The present invention also provides a butter inhibitor, characterized in that it contains, in parts by weight: 3-8 parts of an inhibitor, 1-10 parts of an antioxidant, 5-16 parts of a comb copolymer dispersant, 3-5 parts of a surfactant, and 50-80 parts of deionized water.

[0027] The polymerization inhibitor is selected from at least one of propanolamine, isopropanolamine and hydrazine hydrate.

[0028] The antioxidant is selected from at least one of N,N-diethylhydroxylamine and sodium thiosulfate.

[0029] The surfactant is selected from at least one of sodium dodecylbenzenesulfonate and alkylphenol polyoxyethylene ether.

[0030] Beneficial effects

[0031] The present invention provides a comb-type copolymer dispersant butter inhibitor, which can effectively reduce the generation of butter in an alkali washing tower, effectively enhance the dispersion of butter, and then discharge the alkali washing tower, thereby effectively reducing the pressure difference and extending the operating cycle.

[0032] The invention provides a comb-type copolymer dispersant, which is prepared by copolymerizing monomers A, B and C. Monomers A and B incorporate long polyethylene glycol chains, which have a volume-increasing effect and effectively enhance the water solubility of the dispersant in the caustic wash tower. Furthermore, monomer A incorporates 3,4-dihydroxymandelic acid, which has two phenolic hydroxyl groups and exhibits antioxidant activity. This can reduce the oxygen content in the caustic wash solution and the generation of free radicals caused by oxidation reactions. Oxidation of the phenolic hydroxyl groups generates benzoquinones, which bind to free radicals, inhibiting them and effectively reducing the amount of butter generated by these reactions. Furthermore, 3,4-dihydroxymandelic acid, which has a hydrophobic benzene ring, can enhance the dispersibility of the generated butter through the principle of like-for-like compatibility and the π-π conjugation effect of the benzene ring. Monomer B incorporates DOTA, which, with its multiple carboxyl and amine structures, exhibits a strong chelating effect on metal ions, effectively reducing the metal ion content in the caustic wash solution. This, in turn, reduces the catalytic effect of metal ions on free radical reactions and reduces butter generation. Furthermore, DOTA is highly water-soluble, enhancing the hydrophilicity of the comb copolymer dispersant. Monomer C has a benzene ring, which can effectively adjust the hydrophobicity of the comb-type copolymer dispersant, effectively adjust the amphiphilicity of the high comb-type copolymer dispersant, and enhance the dispersibility of butter.

[0033] The butter inhibitor provided by the present invention comprises a comb copolymer dispersant, a polymerization inhibitor, and a surfactant, which can effectively cooperate to synergistically inhibit the formation of butter and improve the dispersion of butter. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the infrared spectrum of the comb copolymer dispersant.

[0035] Figure 2 This is a synthetic route diagram for comb copolymer dispersants. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] The raw materials used in the embodiments and comparative examples are now described as follows:

[0038] 3,4-Dihydroxymandelic acid: purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0039] 2,2'-Azobis(2-methylbutyronitrile): obtained from Hubei Xinjiecheng Chemical Technology Co., Ltd.

[0040] DOTA-NHS: purchased from Xi'an Qiyue Biotechnology Co., Ltd.

[0041] The components and raw materials used in each parallel experiment or comparative experiment were all of the same kind, and the experimental methods adopted were all carried out under the same conditions. Except for the homemade comb copolymer dispersant, the other chemical raw materials were all commercially available.

[0042] The comb copolymer dispersant is homemade, and the preparation method is as follows:

[0043] S1: Synthesis of monomer A:

[0044] Under nitrogen atmosphere, 3,4-dihydroxymandelic acid was dissolved in anhydrous DMF (N,N-dimethylformamide) solvent, and EDC and NHS were added in sequence, stirred and activated to obtain a 3,4-dihydroxymandelic acid activated solution; the molar ratio of 3,4-dihydroxymandelic acid, EDC, and NHS was 1:1:1.1;

[0045] The activated 3,4-dihydroxymandelic acid solution was added dropwise to the polyethylene glycol diamine (H2N-PEG9-NH2) DMF solution, stirred, reacted fully, and freeze-dried to obtain a 3,4-dihydroxymandelic acid-modified polyethylene glycol compound; the molar ratio of 3,4-dihydroxymandelic acid to polyethylene glycol diamine was 1.1:1.05;

[0046] Acrylic acid was dissolved in a phosphate buffer solution at pH 5.5, and EDC and NHS were added. The mixture was stirred at room temperature for 1 hour to fully activate the carboxyl groups of the acrylic acid to form an acrylic acid carboxyl group activation solution. The molar ratio of acrylic acid, EDC, and NHS was 1:1:1.1.

[0047] The polyethylene glycol compound modified with 3,4-dihydroxymandelic acid is dissolved in a phosphate buffer solution at pH 7.4, and the acrylic acid carboxyl activation solution is added thereto, and the mixture is stirred to fully react, thereby obtaining monomer A.

[0048] The molar ratio of 3,4-dihydroxymandelic acid, polyethylene glycol diamine and acrylic acid is 1.1:1.05:0.95.

[0049] S2: Synthesis of monomer B:

[0050] Dissolve polyethylene glycol diamine (NH2-PEG9-NH2) in pH 7.4 phosphate buffer, add DOTA-NHS ester solution dropwise under stirring, and stir thoroughly to react to obtain DOTA-PEG9-NH2 solution; the molar ratio of DOTA-NHS to polyethylene glycol diamine is 1.1:1.05;

[0051] Acrylic acid was dissolved in a phosphate buffer solution at pH 5.5, and EDC and NHS were added. The mixture was stirred at room temperature for 1 hour to fully activate the carboxyl groups of the acrylic acid to form an acrylic acid carboxyl-activated solution. The acrylic acid carboxyl-activated solution was added dropwise to a DOTA-PEG9-NH2 solution, and the mixture was stirred thoroughly to react to obtain monomer B. The molar ratio of DOTA-NHS, polyethylene glycol diamine, and acrylic acid was 1.1:1.05:0.95.

[0052] S3: Under a nitrogen atmosphere, dissolve monomers A, B, and C in isopropanol. Heat with stirring until the temperature reaches 85°C. Dissolve 2,2'-azobis(2-methylbutyronitrile) in isopropanol and add it to the reaction system. Allow to react for 4 hours. Then, add the initiator 2,2'-azobis(2-methylbutyronitrile) and continue the reaction for another 4 hours. Stop the reaction, dialysis, and freeze-dry. The molar ratio of monomers A, B, and C is 5:5:3.

[0053] The infrared spectrum of the comb-type copolymer prepared by the above specific method is shown in Figure 1 ; Figure 1 Display: amide peak 1673cm -1 The stretching vibration of the phenol CO bond appears at 1240 cm -1 The broad peak of stretching vibration of phenolic hydroxyl group appears at 3200-3550cm -1 Between 1600cm -1 The CC stretching vibration characteristic peaks of the benzene ring appear on the left and right.

[0054] Examples 1-4

[0055] A butter inhibitor, characterized by comprising, in parts by weight: 3-8 parts of hydrazine hydrate (inhibitor), 1-10 parts of N,N-diethylhydroxylamine (antioxidant), 5-16 parts of a comb copolymer dispersant (self-made), 3-5 parts of sodium dodecylbenzenesulfonate (surfactant), and 50-80 parts of deionized water, which are mixed in proportion and stirred evenly.

[0056] Comparative Examples 1-4

[0057] The preparation method is the same as that of Examples 1-4, except that the components or amounts of the butter inhibitor are adjusted.

[0058] Table 1 Butter Inhibitor Ratios for Examples 1-4 and Comparative Examples 1-4

[0059]

[0060] Performance test of butter inhibitor:

[0061] The air flow injection rate of the alkali washing tower is 120 t / h. The butter inhibitors of Examples 1-4 and Comparative Examples 1-4 are injected into the alkali washing tower using an electromagnetic pump. The injection rate of the butter inhibitor is 80 kg / h. The device is operated for 168 h. The content of the polymer in the alkali solution is calculated as follows:

[0062] 1) Polymer content in alkali solution: Take a 5L alkali solution sample from the alkali washing tower and record its mass as M1. After filtering through three layers of filter paper, remove the filter paper and the solid product and dry them at 60°C for 3 hours to obtain the dry material (M2). The mass of the three layers of filter paper is M3. Calculate the polymer content in the alkali solution according to the following formula;

[0063] The content of polymer in alkali solution % = (M2-M3) / M1×100%.

[0064] 2) Alkali washing tower pressure difference: record the pressure values ​​of the pressure gauges at the top and bottom of the tower at 168 hours and calculate the pressure difference.

[0065] Table 2 Performance test results of butter inhibitor

[0066]

[0067] The performance test results of the butter inhibitors in Table 2 show that the butter inhibitors described in Examples 1-4 can effectively reduce the polymer (butter) content and the pressure drop in the caustic wash column. Comparative Example 3 shows that in the absence of a comb copolymer dispersant, the polymer content and pressure drop significantly increase, fully demonstrating that the comb copolymer dispersant significantly reduces polymer aggregation. It also improves polymer dispersion, aiding in the discharge of polymer along with the alkali water, reducing adhesion to the caustic wash column and the resulting increase in pressure drop. Comparative Example 1 shows that in the absence of a polymerization inhibitor, the polymer content and pressure drop are relatively low, further confirming the comb copolymer dispersant's ability to inhibit polymerization and reduce pressure drop. Comparative Examples 2 and 4 show that the antioxidant and surfactant have relatively weak effects. However, the antioxidant enhances the antioxidant effect of the butter inhibitor, further inhibiting free radical polymerization, while the surfactant further enhances the polymer (butter) dispersion properties, thereby reducing pressure drop.

[0068] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.

Claims

1. A comb copolymer dispersant, characterized in that It has the following structural formula (I), (I), m and n are selected from any integers of 5-100, and the molar ratio of monomers A, B, and C for preparing the copolymer is x:y:z=(4-7):(3-5):(3-8).

2. The comb copolymer dispersant according to claim 1, wherein: The preparation method of the comb copolymer dispersant is as follows: S1: Synthesis of monomer A: Under nitrogen atmosphere, 3,4-dihydroxymandelic acid was dissolved in anhydrous N,N-dimethylformamide (DMF) solvent, and EDC and NHS were added in sequence, and stirred for activation to obtain a 3,4-dihydroxymandelic acid activated solution; The activated 3,4-dihydroxymandelic acid solution was added dropwise to the polyethylene glycol diamine H2N-PEGm-NH2 solution, stirred, and reacted fully to obtain a 3,4-dihydroxymandelic acid-modified polyethylene glycol compound; Dissolve acrylic acid in phosphate buffer, add EDC and NHS, and stir at room temperature to fully activate the carboxyl groups of acrylic acid to form an acrylic acid carboxyl group activation solution; The 3,4-dihydroxymandelic acid-modified polyethylene glycol compound is dissolved in a phosphate buffer solution, and an acrylic acid carboxyl activation solution is added thereto, and stirred to fully react to obtain monomer A; S2: Synthesis of monomer B: Dissolve polyethylene glycol diamine NH2-PEGn-NH2 in phosphate buffer, add DOTA-NHS ester solution dropwise under stirring, and stir the reaction thoroughly to obtain DOTA-PEG-NH2 solution; Dissolve acrylic acid in phosphate buffer, add EDC and NHS, and stir at room temperature to fully activate the carboxyl groups of acrylic acid to form an acrylic acid carboxyl group activation solution; The acrylic acid carboxyl activated solution was added dropwise to the DOTA-PEG-NH2 solution and stirred thoroughly to react to obtain monomer B; S3: Under nitrogen atmosphere, monomer A, monomer B, and monomer C were dissolved in isopropanol solution, heated with stirring, and the temperature was raised. 2,2'-azobis(2-methylbutyronitrile) was dissolved in isopropanol and added to the reaction system. The reaction was continued for 4 hours. Subsequently, the initiator 2,2'-azobis(2-methylbutyronitrile) was added and the reaction was continued for 4 hours. The reaction was stopped, purified by dialysis, and freeze-dried.

3. The comb copolymer dispersant according to claim 2, wherein: In step S1, the molar ratio of 3,4-dihydroxymandelic acid, polyethylene glycol diamine, and acrylic acid is (1-1.1): (1-1.05): (0.95-1).

4. The comb copolymer dispersant according to claim 2, wherein: In step S2, the molar ratio of DOTA-NHS, polyethylene glycol diamine, and acrylic acid is (1-1.1): (1-1.05): (1-0.95).

5. The comb copolymer dispersant according to claim 2, wherein: In step S3, the molar ratio of monomer A, monomer B, and monomer C is (4-7): (3-5): (3-8).

6. A butter inhibitor comprising the comb copolymer dispersant according to any one of claims 1 to 5, characterized in that The invention comprises, in parts by weight, 3-8 parts of polymerization inhibitor, 1-10 parts of antioxidant, 5-16 parts of comb copolymer dispersant, 3-5 parts of surfactant and 50-80 parts of deionized water.

7. The butter inhibitor according to claim 6, characterized in that The polymerization inhibitor is selected from at least one of propanolamine, isopropanolamine and hydrazine hydrate.

8. The butter inhibitor according to claim 6, characterized in that The antioxidant is selected from at least one of N,N-diethylhydroxylamine and sodium thiosulfate.

9. The butter inhibitor according to claim 6, characterized in that The surfactant is selected from at least one of sodium dodecylbenzenesulfonate and alkylphenol polyoxyethylene ether.

10. Use of the comb copolymer dispersant according to any one of claims 1 to 5 in the preparation of butter inhibitor.

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