A block ketone aldehyde amine condensate, method of making, corrosion inhibitor and gelled acid

Abstract

The present application relates to carbonate rock formation acidification protection technical field, propose a kind of block type ketone aldehyde amine condensate and preparation method, corrosion inhibitor and gel acid, block type ketone aldehyde amine condensate is obtained by step condensation reaction under catalyst by aniline, cyclohexanone, polyformaldehyde and long aliphatic chain primary amine, it uses the process route of first ketone aldehyde reaction and then dropping amine in preparation, by controlling reaction order and condition, significantly improve the integrity and product purity of condensation reaction, avoid the byproduct problem generated by traditional one-step method, meanwhile, corrosion inhibitor with block type ketone aldehyde amine condensate as main component can still maintain excellent corrosion inhibition performance under harsh conditions of 160 ℃ high temperature and 20% hydrochloric acid, solve the technical problem that existing corrosion inhibitor is not good under high temperature and high acid concentration environment.

Description

Technical Field

[0001] This invention relates to the field of acidification protection technology for carbonate rock formations, and more specifically, to a block ketone-aldehyde-amine condensate and its preparation method, a corrosion inhibitor, and a gel acid. Background Technology

[0002] In acidizing operations in carbonate formations, metal downhole tubing and other equipment are exposed to harsh environments of high temperature and high acidity for extended periods, facing severe corrosion problems. This leads to shortened equipment lifespan, increased operating costs, and even potential safety hazards. Corrosion inhibitors, as an economical and effective means of corrosion prevention, are widely used in this field.

[0003] Traditional inorganic corrosion inhibitors suffer from environmental toxicity issues, limiting their application. Organic corrosion inhibitors, such as imidazoline, quaternary ammonium salts, and Mannich bases, have been widely used, but their corrosion inhibition efficiency decreases significantly at operating conditions above 150°C and acid concentrations greater than 20%. This is mainly because the corrosion inhibitor molecules themselves undergo thermal decomposition or condensation and coking at high temperatures; high temperatures exacerbate the corrosive effect of the medium on the metal; the protective film formed by the corrosion inhibitor adsorption becomes unstable and easily destroyed or desorbed by fluid shear forces; and conventional corrosion inhibitors have simple molecular structures with few adsorption sites, making it difficult to form a dense and robust coating.

[0004] In existing technologies, aldehyde-ketone-amine condensates have attracted attention as a promising class of high-temperature corrosion inhibitors. However, existing solutions mostly employ one-step or simple mixing condensation processes, resulting in products with relatively simple molecular structures and wide molecular weight distributions. These products suffer from problems such as easy decomposition at high temperatures, poor durability of the adsorption film in dynamic shear environments, and tendency to coke on equipment surfaces after long-term use. Particularly for high-temperature deep well acidizing, the corrosion rates of existing corrosion inhibitors often fail to consistently meet industry standards.

[0005] Therefore, developing a corrosion inhibitor with controllable molecular structure, excellent thermal stability, strong shear resistance, and simple synthesis process to solve the corrosion problem of metal equipment under high temperature and high acid environment has important practical significance and application value. Summary of the Invention

[0006] In view of this, the present invention provides a block ketaldehyde-amine condensate and its preparation method, a corrosion inhibitor, and a gelling acid. The block ketaldehyde-amine condensate is prepared by adopting a process route of first reacting the ketaldehyde and then adding the amine dropwise. By controlling the reaction sequence and conditions, the integrity of the condensation reaction and the purity of the product are significantly improved, avoiding the by-product problems of the traditional one-step method. At the same time, the corrosion inhibitor with the block ketaldehyde-amine condensate as the main component can still maintain excellent corrosion inhibition performance under harsh conditions of 160°C and 20% hydrochloric acid, solving the technical problem that existing corrosion inhibitors are not effective in high temperature and high acid concentration environments.

[0007] The technical solution of this invention is as follows:

[0008] In a first aspect, the present invention provides a block ketaldehyde-amine condensate, which is obtained by a stepwise condensation reaction of aniline, cyclohexanone, paraformaldehyde, and a long aliphatic chain primary amine under a catalyst, and its general chemical structure is shown below:

[0009] ;

[0010] In the formula, n = 1 - 2; m = 1 - 2;

[0011] R1 is Where n = 8 - 18;

[0012] R2 is or , where n = 8 - 18.

[0013] Furthermore, the block ketaldehyde-amine condensate is subjected to quaternization treatment to obtain a quaternized block ketaldehyde-amine condensate, the general chemical formula of which is shown below:

[0014] ;

[0015] In the formula, n = 1 - 2; m = 1 - 2;

[0016] R1 is Where n = 8 - 18;

[0017] R2 is or Where n = 8 - 18;

[0018] R3 is , , At least one of them;

[0019] X - It is a halogen element.

[0020] Secondly, based on the same inventive concept, the present invention provides a method for preparing the block ketone-aldehyde-amine condensate as described in any one of the first aspects, comprising the following steps:

[0021] S1. Mix aniline and paraformaldehyde in a solvent, add a catalyst and react at 60-80℃ for 0.5-2h to obtain a polyamine functional group condensation polymer with a degree of polymerization of 1-4.

[0022] S2. Cyclohexanone and paraformaldehyde are mixed in a solvent, a catalyst is added, and the mixture is reacted at 60-80°C for 0.5-2 hours to obtain a polyketone carbonyl intermediate with a degree of polymerization of 2-4.

[0023] S3. Add the polyamine functional group condensate dropwise to the polyketone carbonyl intermediate, controlling the temperature at 60-90℃ during dropwise addition, and then raise the temperature to 90-160℃ to continue the reaction for 2-8 hours to obtain the ketone aldehyde amine condensate.

[0024] S4. Add a long-chain aliphatic primary amine dropwise to the ketaldehyde-amine condensate, controlling the temperature at 60-90°C during the dropwise addition. After the dropwise addition, raise the temperature to 90-160°C and continue the reaction for 2-8 hours to obtain the block ketaldehyde-amine condensate.

[0025] Further, in step S1, the molar ratio of aniline to paraformaldehyde is 1:(1-1.1); in step S2, the molar ratio of cyclohexanone to paraformaldehyde is 1:(1-1.1); in step S3, the molar ratio of the polyketone carbonyl intermediate to the polyamine functional group condensate is (2-4):(1-2); and in step S4, the molar ratio of the ketone-aldehyde-amine condensate to the long aliphatic chain primary amine is 1:(1-2).

[0026] Furthermore, the long aliphatic chain primary amine is one or more of the primary amines with C8-C18 chain length.

[0027] Furthermore, the solvent includes one or more of N,N-dimethylformamide, anhydrous ethanol, isopropanol, methanol, and formamide; the catalyst includes one or more of hydrochloric acid, glacial acetic acid, and formic acid.

[0028] Further, a quaternizing agent is added to the block ketaldehyde amine condensate obtained in step S4, and the reaction is carried out at 50-140°C for 2-4 hours to obtain a quaternized block ketaldehyde amine condensate, wherein the molar ratio of the block ketaldehyde amine condensate to the quaternizing agent is 1:(0.5-2).

[0029] Furthermore, the quaternizing agent includes one or more of benzyl chloride, chloromethylnaphthalene, and dimethyl sulfate.

[0030] Thirdly, the present invention provides a corrosion inhibitor comprising the block ketaldehyde amine condensate described in the first aspect or the block ketaldehyde amine condensate prepared by the preparation method described in the second aspect.

[0031] Fourthly, the present invention provides a corrosion inhibitor, including the corrosion inhibitor described in the third aspect.

[0032] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0033] 1. The block ketaldehyde-amine condensate molecule prepared by this invention contains multiple polar groups (carbonyl and amino groups) and aromatic ring structures, providing superior thermal stability and adsorption capacity. It can form a dense protective film on metal surfaces through chemisorption and physisorption, effectively preventing corrosion. The long aliphatic chain structure provides a certain degree of viscoelasticity, offsetting some of the influence of dynamic shear on molecular adsorption.

[0034] 2. The corrosion inhibitor prepared by this invention has high corrosion inhibition efficiency and stable performance in high temperature and high acid environment, and has good compatibility with oilfield chemicals.

[0035] 3. The optimal corrosion rate of the gelling acid prepared with the corrosion inhibitor of this invention, tested in a high-temperature dynamic reactor at 160℃, 16MPa, 60RPM, and 4h, is 42.36 g / (m³). 2 •h), far below the ≤65 g / (m³) standard of SY / T 5405-2019 2 The requirements of ·h). Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0038] To address the technical problems existing in the prior art, according to one aspect of the embodiments of this disclosure, a block ketone-aldehyde-amine condensate is provided, which is obtained by a stepwise condensation reaction of aniline, cyclohexanone, paraformaldehyde, and a long aliphatic chain primary amine under a catalyst, and its general chemical structural formula is shown below:

[0039] ;

[0040] In the formula, n = 1 - 2; m = 1 - 2;

[0041] R1 is Where n = 8 - 18;

[0042] R2 is or , where n = 8 - 18.

[0043] It is worth noting that this invention synthesizes a block ketaldehyde-amine condensate through molecular design, which exhibits high thermal stability and strong adsorption properties. In summary, the ketone carbonyl and amine groups of the block ketaldehyde-amine condensate can form a stable chelate protective film with the metal surface, which is not easily decomposed even at high temperatures, thereby continuously inhibiting corrosion reactions.

[0044] To enhance the adsorption capacity of the corrosion inhibitor to the metal, this invention incorporates additional adsorption sites in the molecule, enabling the corrosion inhibitor molecules to firmly adsorb onto the metal surface through multi-point adsorption. This multi-point adsorption also provides a degree of resistance to desorption, overcoming the limitation of single-point adsorption where desorption under dynamic shear cannot lead to re-adsorption onto the metal surface. Multi-point adsorption also possesses the ability to dynamically repair desorption under shear force. Furthermore, the six-membered ring and benzene ring increase the decomposition temperature of the corrosion inhibitor molecules, thereby improving their temperature resistance.

[0045] To ensure the solubility of the corrosion inhibitor in acid, the molecular structure designed in this invention is an oligomer.

[0046] Furthermore, the viscoelasticity of the long fatty chains used for end capping at both ends of the molecule in this invention can buffer and consume the impact of dynamic shear on the corrosion inhibitor molecule, thereby reducing the side effects of dynamic shear on adsorption.

[0047] It should be noted that long aliphatic primary amines are not limited to being used as end-capping agents; they can also be used as block segments in reactions.

[0048] In some examples, the block ketaldehyde-amine condensate was quaternized to obtain the quaternized block ketaldehyde-amine condensate, the general chemical formula of which is shown below:

[0049] ;

[0050] In the formula, n = 1 - 2; m = 1 - 2;

[0051] R1 is Where n = 8 - 18;

[0052] R2 is or Where n = 8 - 18;

[0053] R3 is , , At least one of them;

[0054] X - It is a halogen element.

[0055] It is worth noting that after quaternization treatment, the tertiary amine can be reacted into a positively charged quaternary ammonium salt on the basis of the block ketone aldehyde amine condensate, which increases water solubility and endows the block ketone aldehyde amine condensate with ion adsorption ability, thereby improving adsorption performance.

[0056] According to another aspect of the embodiments of this application, a method for preparing a block ketaldehyde-amine condensate is also provided, specifically including:

[0057] S1. Mix aniline and paraformaldehyde in a solvent, add a catalyst and react at 60-80℃ for 0.5-2h to obtain a polyamine functional group condensation polymer with a degree of polymerization of 1-4.

[0058] S2. Mix cyclohexanone and paraformaldehyde in a solvent, add a catalyst and react at 60-80℃ for 0.5-2h to obtain a polyketone carbonyl intermediate with a degree of polymerization of 2-4.

[0059] S3. Add polyamine functional group condensate dropwise to the polyketone carbonyl intermediate, controlling the temperature at 60-90℃ during dropwise addition, and then raise the temperature to 90-160℃ to continue the reaction for 2-8 hours to obtain ketone aldehyde amine condensate.

[0060] S4. Add a long-chain aliphatic primary amine dropwise to the ketaldehyde-amine condensate, controlling the temperature at 60-90℃ during the dropwise addition. After the dropwise addition, raise the temperature to 90-160℃ and continue the reaction for 2-8 hours to obtain a block ketaldehyde-amine condensate.

[0061] It is worth noting that the block ketaldehyde-amine condensate of the present invention adopts a process route of first reacting the ketaldehyde and then adding the amine dropwise. By controlling the reaction sequence and conditions, the integrity of the condensation reaction and the purity of the product are significantly improved, and the by-product problem generated by the traditional one-step method is avoided.

[0062] In some examples, the molar ratio of aniline to paraformaldehyde in step S1 is 1:(1-1.1); the molar ratio of cyclohexanone to paraformaldehyde in step S2 is 1:(1-1.1); the molar ratio of the polyketone carbonyl intermediate to the polyamine functional group condensate in step S3 is (2-4):(1-2); and the molar ratio of the ketone-aldehyde-amine condensate to the long aliphatic chain primary amine in step S4 is 1:(1-2).

[0063] In some examples, the long aliphatic chain primary amine is one or more of the C8-C18 chain length primary amines.

[0064] It should be noted that any of the primary amines with a chain length of C8-C18 can achieve the technical objectives and requirements of this application. Specifically, primary amines with a chain length of C8-C18 can be selected such as dodecylamine or octadecylamine.

[0065] In some examples, the solvent includes one or more of N,N-dimethylformamide, anhydrous ethanol, isopropanol, methanol, and formamide; the catalyst includes one or more of hydrochloric acid, glacial acetic acid, and formic acid.

[0066] In some examples, a quaternizing agent is added to the block ketaldehyde amine condensate obtained in step S4, and the reaction is carried out at 50-140°C for 2-4 hours to obtain a quaternized block ketaldehyde amine condensate.

[0067] In some examples, the molar ratio of block ketaldehyde amine condensate to quaternizing agent is 1:(0.5-2).

[0068] In some examples, the quaternizing agent includes one or more of benzyl chloride, chloromethylnaphthalene, and dimethyl sulfate.

[0069] According to another aspect of the embodiments of this application, a corrosion inhibitor is also provided, including the block ketaldehyde amine condensate as described in any one of the first aspects or the block ketaldehyde amine condensate prepared by the preparation method described in any one of the second aspects.

[0070] It should be noted that the corrosion inhibitors used in the embodiments and comparative examples of this application are all prepared from block ketaldehyde amine condensates, synergists, dispersants, solvents and anhydrous ethanol.

[0071] It should also be noted that the formulation of corrosion inhibitor systems is a mature existing technology in the field. Those skilled in the art can combine existing technology to adjust the corrosion inhibitor components, component dosages and formulation methods according to actual operating conditions. Such adjustments will not affect the technical effect of the block ketone aldehyde amine condensate of this application, so they are not limited in this article.

[0072] According to another aspect of the embodiments of this application, a gel acid is also provided, comprising the corrosion inhibitor described in the third aspect.

[0073] It should be noted that the corrosion inhibitor mentioned in this invention is for gel acid systems, not for the effect of corrosion inhibitors used alone.

[0074] It should also be noted that the gel acid system consists of 20% hydrochloric acid, gelling agent, corrosion inhibitor, acidification drainage aid, acidified clay stabilizer and iron ion stabilizer. This gel acid system is a commercially available and mature formula. Those skilled in the art can adjust it according to existing technology and working conditions.

[0075] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0076] Example 1

[0077] This embodiment 1 provides a block ketaldehyde-amine condensate and its preparation method, which includes the following steps:

[0078] S1. Place 18.6 g of 0.2 mol of aniline and 6.0 g of 0.2 mol of paraformaldehyde in a 250 mL three-necked flask, add 50 mL of N,N-dimethylformamide (DMF) as a solvent, stir to dissolve the solid, slowly add 1% hydrochloric acid as a catalyst, heat to 80 °C, and react for 1 h to obtain a polyamine functional group condensation polymer;

[0079] S2. Place 19.6 g of 0.2 mol of cyclohexanone and 6.0 g of 0.2 mol of paraformaldehyde in a 250 mL three-necked flask, add 50 mL of DMF as solvent, stir to dissolve the solid, slowly add 1% hydrochloric acid as catalyst, heat to 80 °C, and react for 2 h to obtain a polyketone carbonyl intermediate.

[0080] S3. Slowly add the polyamine functional group condensate to the polyketone carbonyl intermediate, controlling the dropping rate to keep the reaction temperature between 60-80℃. The addition is completed in about 1 hour. After the addition, raise the temperature to 100℃ and continue the reaction for 4 hours to obtain the ketone-aldehyde-amine condensate.

[0081] S4. Weigh 18.5 g of 0.1 mol dodecylamine and slowly add it dropwise to a three-necked flask. Control the dropping rate and complete the addition in about 1 hour. Then continue the reaction for another hour. After the reaction is complete, cool to room temperature to obtain a dark red viscous liquid product, which is the block ketone-aldehyde-amine condensate. Its structural formula is shown below:

[0082]

[0083] R1 is Where n=12;

[0084] R2 is .

[0085] Example 2

[0086] Example 2 provides a quaternized block ketaldehyde amine condensate and its preparation method. The preparation method is basically the same as that in Example 1, except that after obtaining the block ketaldehyde amine condensate in step S4, 60g of the product is placed in a 250mL three-necked flask, and 8.3g of 0.07mol of benzyl chloride is added to the three-necked flask. The mixture is stirred at 140℃ for 4h to obtain a bright red viscous liquid product, which is the quaternized block ketaldehyde amine condensate.

[0087]

[0088] R1 is Where n=12;

[0089] R2 is ;

[0090] R3 is ;

[0091] X is Cl.

[0092] Example 3

[0093] This embodiment 3 provides a corrosion inhibitor and its preparation method. The preparation method includes the following steps: weigh 60g of the block ketone aldehyde amine condensate obtained in Example 1, add 5g of allyl alcohol and 1g of potassium iodide as synergists, add 6g of Triton as a dispersant, add 10g of methanol as a solvent, and finally add anhydrous ethanol to 100g, mix and stir evenly to obtain the corrosion inhibitor.

[0094] Example 4

[0095] Example 4 provides a corrosion inhibitor and its preparation method. The preparation method is basically the same as that in Example 3, except that the block ketaldehyde amine condensate obtained in Example 1 is replaced with the quaternized block ketaldehyde amine condensate obtained in Example 2.

[0096] Comparative Example 1

[0097] Comparative Example 1 provides a ketaldehyde-amine condensate and its preparation method, which includes the following steps:

[0098] Take 19.6 g of 0.2 mol cyclohexanone and 6.0 g of 0.2 mol paraformaldehyde and place them in a 250 mL three-necked flask. Add 100 g of DMF as a solvent and react at 80 °C for 2 h. Then slowly add 18.6 g of 0.2 mol aniline to the three-necked flask, controlling the dropping rate to complete the addition within 1 h. Then raise the temperature to 140 °C and react for 4 h to obtain a dark red liquid product, which is the ketaldehyde-amine condensate.

[0099] It is worth noting that this comparative example does not employ long fatty chain and block reactions.

[0100] Comparative Example 2

[0101] Comparative Example 2 provides a quaternized ketaldehyde amine condensate and its preparation method. The preparation method is basically the same as that of Comparative Example 1, except that after obtaining the ketaldehyde amine condensate, 60g of the condensate is placed in a 250ml three-necked flask, and 8.3g of 0.07mol benzyl chloride is added to the three-necked flask. The mixture is stirred at 140℃ for 4h to obtain a bright red viscous liquid product, which is the quaternized ketaldehyde amine condensate.

[0102] Comparative Example 3

[0103] Comparative Example 3 provides a corrosion inhibitor and its preparation method. The preparation method is basically the same as that of Example 3, except that the block ketaldehyde amine condensate obtained in Example 1 is replaced with the ketaldehyde amine condensate obtained in Comparative Example 1.

[0104] Comparative Example 4

[0105] Comparative Example 4 provides a corrosion inhibitor and its preparation method. The preparation method is basically the same as that of Example 3, except that the block ketaldehyde amine condensate obtained in Example 1 is replaced with the quaternized ketaldehyde amine condensate obtained in Comparative Example 2.

[0106] Comparative Example 5

[0107] Comparative Example 5 provides a block ketaldehyde-amine condensate and its preparation method. The preparation method is basically the same as that in Example 1, except that aniline in step S1 is replaced with 37.0 g of 0.2 mol of dodecylamine. The structural formula of the resulting block ketaldehyde-amine condensate is shown below:

[0108]

[0109] R1 is Where n=12;

[0110] It is worth noting that in Comparative Example 5, aniline was replaced with dodecylamine to verify the effect of replacing the short-chain structure of the structural intermediate with a long-chain structure on product performance.

[0111] Comparative Example 6

[0112] Comparative Example 6 provides a quaternized block ketaldehyde-amine condensate and its preparation method. The preparation method is basically the same as that of Example 2, except that the block ketaldehyde-amine condensate is selected from the block ketaldehyde-amine condensate obtained in Comparative Example 5, resulting in a quaternized block ketaldehyde-amine condensate with the following structural formula:

[0113]

[0114] R1 is Where n=12;

[0115] R2 is ;

[0116] X is Cl.

[0117] Comparative Example 7

[0118] Comparative Example 7 provides a corrosion inhibitor, which is prepared in a manner that is basically the same as that of Example 3, except that the block ketaldehyde amine condensate obtained in Example 1 is replaced with the block ketaldehyde amine condensate obtained in Comparative Example 5.

[0119] Comparative Example 8

[0120] Comparative Example 8 provides a corrosion inhibitor, which is prepared in a manner that is basically the same as that of Example 3, except that the block ketaldehyde amine condensate obtained in Example 1 is replaced with the quaternized block ketaldehyde amine condensate obtained in Comparative Example 6.

[0121] To better understand the present invention, the following tests were performed on the embodiments and comparative examples.

[0122] According to the standard and method of SY / T 5405-2019 "Test Method and Evaluation Index of Corrosion Inhibitors for Acidification", the corrosion inhibitors obtained in Examples 3-4 and Comparative Examples 3-4 and 7-8 were prepared into the acidification system (gel acid) to form a test system. The concentration of the corrosion inhibitor was 4%. The specific composition of the test system was: 2.5% gelling agent, 4% corrosion inhibitor, 1% clay stabilizer, 1% iron ion stabilizer, 1% drainage aid, 20% hydrochloric acid and the balance water.

[0123] It should be noted that the gelling agents used in the test were all cationic polyacrylamide emulsions; the clay stabilizers used were all quaternary ammonium salts, specifically, copolymers of dimethyl diallyl ammonium chloride (DMDAAC) and acrylamide (AM); the iron ion stabilizers used were all citric acid solutions; the drainage aids used were all quaternary ammonium salt surfactants; and the 20% hydrochloric acid used was obtained by diluting 37% concentrated hydrochloric acid.

[0124] Test Example 1

[0125] Test Example 1 shows the solution states of the product, its prepared corrosion inhibitor, and the gel acid system before and after the corrosion experiment. The results are shown in Table 1.

[0126]

[0127] As shown in Table 1, the gelling acid system prepared by the corrosion inhibitor made from the ketone-aldehyde-amine condensate treated with block and long aliphatic chain end caps does not generate coking material after corrosion experiments.

[0128] Test Example 2

[0129] Test Example 2 presents a corrosion rate experiment of the gel acid system according to SY / T 5405-2019 "Test Methods and Evaluation Indicators for Corrosion Inhibitors for Acidification", with a test condition of 160℃. The results are shown in Table 2.

[0130]

[0131] Table 2 shows that the corrosion inhibitor formulated from ketaldehyde-amine condensates treated with block and long aliphatic chain end-capping exhibits a corrosion rate that meets industry standards. Furthermore, under the same conditions, the test data for this corrosion inhibitor is superior to that of corrosion inhibitors formulated from conventional ketaldehyde-amine condensates. Secondly, the test performance after quaternization treatment is better than that without quaternization treatment, indicating that the adsorption performance is improved to some extent after quaternization.

[0132] Compared to corrosion inhibitors formulated using ketaldehyde-amine condensates synthesized from dodecylamine, corrosion inhibitors formulated using ketaldehyde-amine condensates synthesized from aniline exhibit superior corrosion rates. This indicates that the presence of long-chain groups in dodecylamine can effectively reduce the corrosion rate, and the selective combination with benzene ring structures further enhances the rigidity and temperature resistance of the molecule, thereby improving the performance of the corrosion inhibitor.

[0133] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0134] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A block ketone aldehyde amine condensate, characterized by, The block type ketone aldehyde amine condensate is obtained by step-by-step condensation reaction of aniline, cyclohexanone, paraformaldehyde and long fatty chain primary amine under a catalyst, and its chemical structure is shown in the following general formula: ； In the formula, n=1-2; m=1-2; R1is wherein n = 8-18; R2 is phenyl.

2. The condensate of claim 1, wherein, The block type ketone aldehyde amine condensate is subjected to quaternary ammonium treatment to obtain a quaternary ammonium block type ketone aldehyde amine condensate, and its chemical structure is shown in the following general formula: ； In the formula, n=1-2; m=1-2; R1is wherein n = 8-18; R2 is phenyl; R3 is at least one of benzyl and naphthylmethyl; X - is a halogen element.

3. A process for producing the block ketone aldehyde amine condensate according to claim 1, characterized by, The method comprises the following steps: S1. Aniline is mixed with paraformaldehyde in a solvent, a catalyst is added, and reaction is carried out at 60-80°C for 0.5-2h to obtain a polyamine functional group condensate with a polymerization degree of 1-4; S2. Cyclohexanone is mixed with paraformaldehyde in a solvent, a catalyst is added, and reaction is carried out at 60-80°C for 0.5-2h to obtain a polyketone carbonyl intermediate with a polymerization degree of 2-4; S3. The polyketone carbonyl intermediate is added dropwise with the polyamine functional group condensate, the temperature is controlled at 60-90°C during dropwise addition, and after dropwise addition, the temperature is raised to 90-160°C for continuous reaction for 2-8h to obtain a ketone aldehyde amine condensate; S4. The ketone aldehyde amine condensate is added dropwise with long fatty chain primary amine, the temperature is controlled at 60-90°C during dropwise addition, and after dropwise addition, the temperature is raised to 90-160°C for continuous reaction for 2-8h to obtain the block type ketone aldehyde amine condensate.

4. The method of claim 3, wherein, The molar ratio of aniline to paraformaldehyde in the step S1 is 1:(1-1.1); the molar ratio of cyclohexanone to paraformaldehyde in the step S2 is 1:(1-1.1); the molar ratio of the polyketone carbonyl intermediate to the polyamine functional group condensate in the step S3 is (2-4):(1-2); and the molar ratio of the ketone aldehyde amine condensate to long fatty chain primary amine in the step S4 is 1:(1-2).

5. The method of claim 3, wherein, The long fatty chain primary amine is one or more of C8-C18 chain length primary amines.

6. The method of claim 3, wherein, The solvent comprises one or more of N,N-dimethylformamide, anhydrous ethanol, isopropyl alcohol, methanol and formamide; and the catalyst comprises one or more of hydrochloric acid, glacial acetic acid and formic acid.

7. The method of claim 3, wherein, A quaternary ammonium reagent is added to the block type ketone aldehyde amine condensate obtained in the step S4, and reaction is carried out at 50-140°C for 2-4h to obtain a quaternary ammonium block type ketone aldehyde amine condensate, wherein the molar ratio of the block type ketone aldehyde amine condensate to the quaternary ammonium reagent is 1:(0.5-2).

8. The method of claim 7, wherein, The quaternary ammonium reagent comprises one or more of benzyl chloride and chloromethyl naphthalene.

9. An inhibitor characterized in that, The block type ketone aldehyde amine condensate of any one of claims 1-2 or the block type ketone aldehyde amine condensate prepared by the method of any one of claims 3-8.

10. A gelled acid characterized in that, The corrosion inhibitor of claim 9.

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