阅读说明：本技术 一种对叔丁基苯甲酸衍生物及其作为金属防锈剂的应用 (P-tert-butyl benzoic acid derivative and application thereof as metal antirust agent ) 是由 冯鹏举 于 2019-11-04 设计创作，主要内容包括：本发明提供了一种对叔丁基苯甲酸衍生物及其作为金属防锈剂的应用,属于金属防锈剂技术领域。本发明提供的对叔丁基苯甲酸衍生物具有式I所示结构,此对叔丁基苯甲酸衍生物以对叔丁基苯甲酸为骨架,对叔丁基苯甲酸与具有氨基酸前体结构的酰胺类化合物反应生成稳定的化合物,具有良好的防锈性能；由于本发明提供的对叔丁基苯甲酸衍生物具有非天然氨基酸的衍生物结构,无毒性,可生物降解,水溶性优秀,易于纯化,价格较低,能够满足开发绿色环保金属防锈剂的要求。本发明提供的对叔丁基苯甲酸衍生物用作金属防锈剂时,具有良好的金属防锈效果,在防锈性测试中能够保持48h无锈迹,防锈效果优于传统癸二酸金属防锈剂。(The invention provides a p-tert-butyl benzoic acid derivative and application thereof as a metal antirust agent, belonging to the technical field of metal antirust agents. The p-tert-butyl benzoic acid derivative has a structure shown in a formula I, takes p-tert-butyl benzoic acid as a skeleton, and reacts with an amide compound with an amino acid precursor structure to generate a stable compound, so that the p-tert-butyl benzoic acid derivative has good antirust performance; the p-tert-butyl benzoic acid derivative provided by the invention has a derivative structure of unnatural amino acid, is nontoxic, biodegradable, excellent in water solubility, easy to purify and low in price, and can meet the requirement of developing a green and environment-friendly metal antirust agent. When the p-tert-butyl benzoic acid derivative provided by the invention is used as a metal antirust agent, the p-tert-butyl benzoic acid derivative has a good metal antirust effect, can keep 48h of no rust in an antirust property test, and has an antirust effect superior to that of a traditional sebacic acid metal antirust agent.)

1. A p-tert-butyl benzoic acid derivative, characterized by having the structure shown in formula I:

in the formula I, R is

2. Use of the p-tert-butylbenzoic acid derivative as defined in claim 1 as a metal rust inhibitor.

3. The application according to claim 2, characterized in that the method of application comprises the steps of:

mixing the p-tert-butyl benzoic acid derivative with triethanolamine, sodium hydroxide and water to obtain a metal antirust agent mixed solution;

and coating or spraying the metal antirust agent mixed solution on the surface of the metal product, or immersing the metal product in the metal antirust agent mixed solution and then taking out the metal product.

4. Use according to claim 3, characterized in that the mass ratio of the p-tert-butylbenzoic acid derivative to triethanolamine, sodium hydroxide and water is (0.8 to 1.2): (0.8-1.2): (0.8-1.2): (150-250).

Technical Field

The invention relates to the technical field of metal rust inhibitors, in particular to a p-tert-butyl benzoic acid derivative and application thereof as a metal rust inhibitor.

Background

Metal corrosion refers to a phenomenon in which a metal material chemically reacts with substances in the surrounding environment to change the structure and properties of the material. Metal corrosion is common in every aspect of daily life and industrial production, and although it seems common, it has a great influence on the aspects of economy, safety, environmental protection and the like. For example, according to a survey conducted by the Chinese institute of technology in 2015, metal corrosion and its effects cause an economic loss of 2.1 trillion RMB to China each year, accounting for about 3.3% of GDP throughout the country, with the most severely affected being the transportation and electronics industries. In addition, there are many reports on the safety of metal corrosion, especially on the life safety of human beings. Therefore, the metal corrosion phenomenon should be sufficiently considered.

The use of rust inhibitors (CI) is widely recognized as the most effective and most practical method of preventing Corrosion. The mechanism of action of metal rust inhibitors can be broadly classified into the following three types: 1) the molecules of the antirust agent are adsorbed on the surface of the material and form a layer of protective film; 2) the antirust agent induces the metal surface to form a layer of oxide film; 3) the rust inhibitor molecules react directly with corrosive substances in the surroundings of the material. A lot ofOrganic and inorganic compounds can be used for metal rust inhibitors, and active ingredients of rust inhibitors reported in the literature generally contain some heteroatoms (such as N, S, P, O and the like), multiple bonds and specific functional groups (such as-OH, -COOH and-NH)₂Etc.).

Most of common rust inhibitors on the market contain toxic and harmful components and damage the environment to different degrees. Therefore, various countries and environmental protection departments put forward higher standards for using and discharging the rust inhibitor according to stricter environmental protection requirements, and researchers also tend to focus on designing a novel environment-friendly rust inhibitor.

Disclosure of Invention

In view of the above, the present invention aims to provide a p-tert-butyl benzoic acid derivative and its application as a metal rust inhibitor. The p-tert-butyl benzoic acid derivative provided by the invention is environment-friendly and low in cost, and has a good antirust effect when being used as a metal antirust agent.

In order to achieve the above object, the present invention provides the following solutions:

the invention provides a p-tert-butyl benzoic acid derivative which has a structure shown in a formula I:

in the formula I, R is

The invention provides application of the p-tert-butyl benzoic acid derivative as a metal antirust agent.

Preferably, the method of application comprises the steps of:

mixing the p-tert-butyl benzoic acid derivative with triethanolamine, sodium hydroxide and water to obtain a metal antirust agent mixed solution;

and coating or spraying the metal antirust agent mixed solution on the surface of the metal product, or immersing the metal product in the metal antirust agent mixed solution and then taking out the metal product.

Preferably, the mass ratio of the p-tert-butyl benzoic acid derivative to the triethanolamine to the sodium hydroxide to the water is (0.8-1.2): (0.8-1.2): (0.8-1.2): (150-250).

The invention provides a p-tert-butyl benzoic acid derivative which has a structure shown in a formula I; the p-tert-butyl benzoic acid derivative takes p-tert-butyl benzoic acid as a framework, the p-tert-butyl benzoic acid reacts with an amide compound with an amino acid precursor structure to generate a stable compound, and the compound has good antirust performance because of the fact that the compound has carboxyl capable of being effectively combined with metal and a tert-butyl shielding group with large steric hindrance; the p-tert-butyl benzoic acid derivative provided by the invention has a derivative structure of unnatural amino acid, is nontoxic, biodegradable, excellent in water solubility, easy to purify and low in price, and can meet the requirement of developing a green and environment-friendly metal antirust agent.

The invention provides application of the p-tert-butyl benzoic acid derivative as a metal antirust agent. When the p-tert-butyl benzoic acid derivative provided by the invention is used as a metal antirust agent, the p-tert-butyl benzoic acid derivative has a good metal antirust effect, can keep 48h of no rust in an antirust property test, and has an antirust effect superior to that of a traditional sebacic acid metal antirust agent.

Drawings

FIG. 1 is a graph comparing the rust inhibitive performance of sebacic acid with that of Compound A after 48 hours in example 1;

FIG. 2 is a graph comparing the rust inhibitive performance of sebacic acid with that of compound B after 48 hours in example 2;

FIG. 3 is a graph comparing the rust inhibitive performance of sebacic acid with that of compound C after 48 hours in example 3;

FIG. 4 is a graph comparing the rust inhibitive performance of sebacic acid with that of compound D after 48 hours in example 4;

FIG. 5 is a graph comparing the rust inhibitive performance of sebacic acid with that of compound E after 48 hours in example 5;

FIG. 6 is a graph comparing the rust inhibitive performance of sebacic acid with that of compound F after 48 hours in example 6;

FIG. 7 is a graph showing the comparison of the rust inhibitive performance of sebacic acid with that of compound G after 48 hours in example 7.

Detailed Description

The invention provides a p-tert-butyl benzoic acid derivative which has a structure shown in a formula I:

in the formula I, R is

In the present invention, when R isWhen the structure of the p-tert-butyl benzoic acid derivative is shown as a formula A, the p-tert-butyl benzoic acid derivative is marked as a compound A;

in the present invention, the preparation method of the compound a preferably includes the steps of:

(1) mixing p-tert-butyl benzoic acid and thionyl chloride, and carrying out acyl chlorination reaction to obtain p-tert-butyl benzoyl chloride;

(2) mixing N-methylpyrrolidone and an aqueous solution of sodium hydroxide, and carrying out a ring-opening reaction to obtain an aqueous solution of a ring-opening product;

(3) mixing the p-tert-butylbenzoyl chloride with the aqueous solution of the ring-opening product, carrying out a substitution reaction, and adjusting a substitution reaction solution to be acidic to obtain a compound A;

the steps (1) and (2) are not limited in time sequence.

The p-tert-butyl benzoic acid and thionyl chloride are preferably mixed for acyl chlorination reaction to obtain the p-tert-butyl benzoyl chloride. In the present invention, the molar ratio of the p-tert-butyl benzoic acid to the thionyl chloride is preferably 250:0.88, the time of the acyl chlorination reaction is preferably 4 hours, the acyl chlorination reaction is preferably performed under reflux conditions, and the reaction is heated to the reflux temperature of the system. After the completion of the acid chlorination reaction, it is preferable in the present invention that the resultant acid chlorination reaction liquid is subjected to evaporation under reduced pressure to remove unreacted thionyl chloride. In the invention, the temperature of the reduced pressure evaporation is preferably 0-50 ℃, and the pressure is preferably 92-350 kPa.

In the present invention, the reaction formula of the acyl chlorination reaction is shown as formula a:

in the present invention, it is preferable that N-methylpyrrolidone is mixed with an aqueous solution of sodium hydroxide to carry out a ring-opening reaction to obtain an aqueous solution of a ring-opening product. In the present invention, the mass concentration of the aqueous sodium hydroxide solution is preferably 0.08g/mL, and the molar ratio of the N-methylpyrrolidone to the sodium hydroxide is preferably 303: 500. In the invention, the temperature of the ring-opening reaction is preferably 30-100 ℃, more preferably 50-80 ℃, and the time is preferably 1-8 hours, more preferably 4-6 hours. The invention does not need to carry out post-treatment on the ring-opening product aqueous solution, and the ring-opening product aqueous solution can be directly used for the next reaction.

In the present invention, the reaction formula of the ring-opening reaction is shown as formula b:

after the p-tert-butylbenzoyl chloride and the aqueous solution of the ring-opening product are obtained, the p-tert-butylbenzoyl chloride and the aqueous solution of the ring-opening product are preferably mixed for substitution reaction, and the substitution reaction solution is adjusted to be acidic to obtain the compound A. The invention preferably adds p-tert-butylbenzoyl chloride slowly and dropwise into the ring-opening product water solution. In the present invention, the temperature of the substitution reaction is preferably room temperature, and the time is preferably 2 hours. In the present invention, the pH of the substitution reaction solution is preferably adjusted to 2 to 3, and the pH adjusting agent is preferably concentrated hydrochloric acid. After the pH value is adjusted, the present invention preferably performs a post-treatment on the acidic reaction solution after the pH value is adjusted, and the post-treatment preferably includes the following steps:

and sequentially extracting, washing and decompressing and evaporating the acidic reaction solution to obtain a pure compound A.

In the present invention, the extractant for extraction is preferably ethyl acetate; the washing detergent is preferably distilled water; the present invention has no particular requirement on the specific operation modes of the extraction, the washing and the reduced pressure evaporation, and the operation modes can be realized by using the operation modes which are well known to those skilled in the art.

In the present invention, the chemical formula of the substitution reaction is shown as formula c:

in the present invention, when R isWhen the compound is used, the structure of the p-tert-butyl benzoic acid derivative is shown as a formula B and is marked as a compound B;

in the present invention, the preparation method of the compound B preferably includes the steps of:

(1) mixing N-methylpyrrolidone and an aqueous solution of sodium hydroxide, and carrying out a ring-opening reaction to obtain an aqueous solution of a ring-opening product;

(2) and mixing the ring-opening reaction water solution with p-tert-butyl benzoic acid for association reaction to obtain a compound B.

In the present invention, the specific conditions of the ring-opening reaction are preferably the same as those of the ring-opening reaction in the preparation of the compound a, and are not described herein again, and the reaction formula of the ring-opening reaction is shown as the formula b above.

After the aqueous solution of the ring-opening product is obtained, the present invention preferably mixes the aqueous solution of the ring-opening reaction with p-tert-butylbenzoic acid to perform an association reaction to obtain compound B. In the invention, the molar ratio of the p-tert-butylbenzoic acid to the ring-opened N-methylpyrrolidone is preferably 1:1, the temperature of the association reaction is preferably room temperature, and the time is preferably 1-5 h, and more preferably 2-4 h; the present invention preferably performs the association reaction under stirring conditions. After the association reaction, the present invention preferably performs reduced pressure evaporation on the obtained association reaction solution to obtain a dried compound B.

In the present invention, the association reaction in preparing compound B is represented by the formula d:

in the present invention, when R isWhen the structure of the p-tert-butyl benzoic acid derivative is shown as a formula C, the structure is marked as a compound C;

in the present invention, the preparation method of the compound C preferably includes the steps of:

mixing N-methyl pyrrolidone, p-tert-butyl benzoic acid and a solvent, and carrying out association reaction to obtain a compound C.

In the present invention, the solvent is preferably ethyl acetate; the dosage ratio of the N-methylpyrrolidone to the p-tert-butyl benzoic acid to the solvent is preferably 5g to 9g to 40 mL. In the invention, the temperature of the association reaction is preferably 20-50 ℃, more preferably 30-40 ℃, and the time is preferably 1-5 hours, more preferably 2-4 hours. The present invention preferably performs the association reaction under stirring conditions. After the association reaction is completed, the invention preferably performs vacuum filtration on the obtained association reaction liquid to remove the solvent in the association reaction liquid. In the present invention, the temperature of the reduced pressure suction filtration is preferably 40 ℃; in the present invention, it is preferable to perform suction filtration under reduced pressure with stirring.

In the present invention, the association reaction when preparing compound C has the formula shown in formula e:

in the present invention, when R isWhen the structure of the p-tert-butyl benzoic acid derivative is shown as a formula D, the p-tert-butyl benzoic acid derivative is marked as a compound D;

in the present invention, the preparation method of the compound D preferably includes the steps of:

mixing N, N-dimethylformamide, p-tert-butyl benzoic acid and a solvent, and carrying out association reaction to obtain a compound D.

In the present invention, the solvent is preferably ethyl acetate; the dosage ratio of the N, N-dimethylformamide to the p-tert-butylbenzoic acid to the solvent is preferably 3.7g to 9g to 40 mL. In the present invention, the reaction conditions, operation mode and post-treatment method of the association reaction are the same as those in the preparation of compound C, and are not described herein again.

In the invention, the reaction formula of the association reaction in the preparation of the compound D is shown as a formula f;

in the present invention, when R isWhen the structure of the p-tert-butyl benzoic acid derivative is shown as a formula E, the p-tert-butyl benzoic acid derivative is marked as a compound E;

in the present invention, the preparation method of the compound E preferably includes the steps of:

mixing N, N-dimethylacetamide and p-tert-butyl benzoic acid with a solvent, and carrying out association reaction to obtain a compound E.

In the present invention, the solvent is preferably ethyl acetate; the dosage ratio of the N, N-dimethylacetamide, the p-tert-butyl benzoic acid and the solvent is preferably 4.4g:9g:40 mL. In the present invention, the reaction conditions, operation mode and post-treatment method of the association reaction are the same as those in the preparation of compound C, and are not described herein again.

In the invention, the reaction formula of the association reaction in the preparation of the compound E is shown as a formula g;

in the present invention, when R isWhen the structure of the p-tert-butyl benzoic acid derivative is shown as a formula F, the structure is marked as a compound F;

in the present invention, the preparation method of the compound F preferably includes the steps of:

mixing 1, 3-dimethyl propylene urea, p-tert-butyl benzoic acid and a solvent, and carrying out association reaction to obtain a compound F.

In the present invention, the solvent is preferably ethyl acetate; the dosage ratio of the 1, 3-dimethyl propylene urea, the p-tert-butyl benzoic acid and the solvent is preferably 6.5g to 9g to 40 mL. In the present invention, the reaction conditions, operation mode and post-treatment method of the association reaction are the same as those in the preparation of compound C, and are not described herein again.

In the invention, the reaction formula of the association reaction in the preparation of the compound F is shown as a formula h;

in the present invention, when R isWhen the structure of the p-tert-butyl benzoic acid derivative is shown as a formula G, the structure is marked as a compound G;

in the present invention, the preparation method of the compound G preferably comprises the steps of:

mixing 1, 3-dimethyl-2-imidazolidinone and p-tert-butyl benzoic acid with a solvent, and carrying out association reaction to obtain a compound G.

In the present invention, the solvent is preferably ethyl acetate; the dosage ratio of the 1, 3-dimethyl-2-imidazolidinone, the p-tert-butyl benzoic acid and the solvent is preferably 5.8g to 9g to 40 mL. In the present invention, the reaction conditions, operation mode and post-treatment method of the association reaction are the same as those in the preparation of compound C, and are not described herein again.

In the invention, the reaction formula of the association reaction in the preparation of the compound G is shown as a formula i;

the invention provides application of the p-tert-butyl benzoic acid derivative as a metal antirust agent. In the invention, the p-tert-butyl benzoic acid derivative takes p-tert-butyl benzoic acid as a skeleton, and the p-tert-butyl benzoic acid reacts with the amide compound with an amino acid precursor structure to generate a stable compound, so that the p-tert-butyl benzoic acid derivative has good antirust performance; the p-tert-butyl benzoic acid derivative provided by the invention has a derivative structure of unnatural amino acid, is nontoxic, biodegradable, excellent in water solubility, easy to purify and low in price, and can meet the requirement of developing a green and environment-friendly metal antirust agent.

In the present invention, the method of application preferably comprises the steps of:

mixing the p-tert-butyl benzoic acid derivative with triethanolamine, sodium hydroxide and water to obtain a metal antirust agent mixed solution;

and coating and spraying the metal antirust agent mixed solution on the surface of the metal product or taking out the metal product after immersing the metal product in the metal antirust agent mixed solution.

In the present invention, it is preferable to mix the p-tert-butylbenzoic acid derivative with triethanolamine, sodium hydroxide and water to obtain a metal rust inhibitor mixture. In the present invention, the mass ratio of the p-tert-butylbenzoic acid derivative, triethanolamine, sodium hydroxide and water is preferably (0.8 to 1.2): (0.8-1.2): (0.8-1.2): (150 to 250), more preferably (0.9 to 1.1): (0.9-1.1): (0.9-1.1): (180-220), and most preferably 1:1:1: 198. The present invention does not require any special mixing means, and the above components can be mixed uniformly by using a mixing means known to those skilled in the art. In the present invention, the triethanolamine functions to improve the solubility of the metal rust inhibitor, and the sodium hydroxide functions to neutralize the metal rust inhibitor and form the rust inhibitor into a sodium salt, thereby improving the solubility of the metal rust inhibitor.

After the metal antirust agent mixed solution is obtained, the metal antirust agent mixed solution is preferably coated or sprayed on the surface of a metal product, or the metal product is taken out after being immersed in the metal antirust agent mixed solution. In the present invention, the material of the metal product is preferably cast iron, stainless steel (full series), aluminum alloy (7050, 7075 series), and the present invention has no special requirement for the specific operation mode of coating, spraying or immersing, and the above-mentioned modes known to those skilled in the art can be used.

The p-tert-butyl benzoic acid derivatives and their use as metal rust inhibitors provided by the present invention will be described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.

Example 1

P-tert-butylbenzoic acid (250mmol, 45g) and thionyl chloride (0.88mmol, 104g) were charged into a 250mL flask equipped with a condenser tube, heated to reflux for 4 hours, and after the reaction was completed, thionyl chloride was evaporated under reduced pressure to obtain a yellow liquid which was p-tert-butylbenzoyl chloride.

250mL of water and sodium hydroxide (20g, 500mmol) were added to a 500mL flask at room temperature, sufficiently stirred to dissolve, NMP (30g, 303mmol) was added in one portion, and the solution was heated to 80 ℃ to react for 4 hours, thereby obtaining an aqueous solution of a product after ring opening was sufficiently hydrolyzed by NMP.

Slowly and dropwise adding the prepared yellow p-tert-butylbenzoyl chloride liquid (60g, 303mmol) into the NMP ring-opening solution prepared in the last step, keeping the reaction temperature above or below room temperature, fully stirring for 2 hours, adjusting the pH of the mixture to a range of 2-3 by using concentrated hydrochloric acid, extracting by using 30mL of ethyl acetate, repeatedly washing and stirring by using distilled water, and removing the volatile solvent under reduced pressure to obtain a compound A which is viscous oily liquid.

Compound a was structurally characterized by nuclear magnetic resonance and the data obtained were as follows:

¹H-NMR(300MHz,CDCl₃,25℃,δ)：8.10(d,2H),7.51(d,2H),3.39(t,2H),2.93(s,3H),2.52(t,2H),2.10(m,2H),1.32(s,9H)。

¹³C-NMR(75MHz,CDCl₃,25℃,δ)：180.1,172.1,154.3,134.1,126.8,125.3,40.6,36.0,34.1,31.2,29.7,21.7。

the rust-proof performance of the compound A is tested according to the national standard GB/T6144, and the method comprises the following steps:

weighing 0.5g of the prepared compound A, adding the compound A into a beaker filled with 99g of water, adding 0.5g of triethanolamine and 0.5g of sodium hydroxide into the solution, fully stirring until the solution is transparent and clear, taking 5g of the solution, mixing the solution with about 10g of scrap iron, shaking up, pouring off the upper solution, spreading the fully rinsed scrap iron on filter paper, and placing the filter paper filled with the scrap iron in a ventilated place. For comparison, the same quality of conventional sebacic acid rust inhibitor was used in combination with triethanolamine and sodium hydroxide for rust inhibition performance testing under the same operating conditions.

As a result of observation after 12 hours, it was found that no rust was formed on the filter paper using compound A as a metal rust inhibitor. The observation time was prolonged to 48 hours, and any rust was not observed. On the other hand, a large number of rust spots (about 55 rust spots) were formed on the filter paper using sebacic acid as a rust inhibitor after 48 hours, wherein the rust inhibitive performance of sebacic acid after 48 hours is shown in fig. 1 in comparison with compound a. Therefore, the compound A has a good rust-preventing effect when used as a metal rust inhibitor.

Example 2

250mL of water and sodium hydroxide (20g, 500mmol) were added to a 500mL flask at room temperature, sufficiently stirred to dissolve, NMP (30g, 303mmol) was added in one portion, and the solution was heated to 80 ℃ to react for 4 hours, thereby obtaining an aqueous solution of a product after ring opening was sufficiently hydrolyzed by NMP.

Adding p-tert-butyl benzoic acid (54g, 303mmol) into the aqueous solution at one time, continuously stirring at room temperature for 3 hours until all solids are dissolved, and obtaining light yellow solid powder, namely the compound B, wherein the solution is clear and transparent, and water is evaporated under reduced pressure at 60 ℃.

Compound B was structurally characterized by nuclear magnetic resonance and the data obtained were as follows:

¹H-NMR(300MHz,D₂O,25℃,δ)：7.83(d，2H),7.32(d,2H),3.20-2.85(m,2H),2.60(s,3H),2.30-2.12(m,2H),1.92-1.65(m,2H),1.12(s,9H)。

¹³C-NMR(75MHz,D₂O,25℃,δ)：178.6,170.5,154.1,133.0,125.0,121.4,50.3,36.2,30.5,28.3,27.6,19.4。

the rust inhibitive performance of compound B was tested using the method of example 1 and a conventional sebacic acid rust inhibitive agent was used as a comparison, and the result showed that no rust was formed on the filter paper with compound B as a metal rust inhibitive agent after 12 hours. After the observation time was prolonged to 48 hours, no rust was found, and a large number of rust spots were formed on the filter paper using sebacic acid as a rust inhibitor after 48 hours, wherein the rust inhibitive performance of sebacic acid after 48 hours was compared with that of compound B as shown in fig. 2. Therefore, the compound B has a good rust-preventing effect when used as a metal rust inhibitor.

Example 3

5g of NMP was mixed with 40mL of ethyl acetate to obtain a colorless transparent solution; to the above colorless transparent solution was added 9g of p-tert-butylbenzoic acid in one portion, stirred well at 20 ℃ for 2 hours until all the solid was dissolved, and the solvent was drained under reduced pressure at 40 ℃ while the mixture was stirred rapidly to give a white crystalline solid as compound C.

Compound C was characterized by nmr and the data obtained were as follows:

¹H-NMR(300MHz,CDCl₃,25℃,δ)：8.06(d,2H),7.50(d,2H),3.41(t,2H),2.88(s,3H),2.45(t,2H),2.05(m,2H),1.36(s,9H)。

¹³C-NMR(75MHz,CDCl₃,25℃,δ)：175.6,171.0,157.1,130.0,127.0,125.4,49.6,35.2,31.1,30.6,29.7,17.7。

the rust inhibitive performance of compound C was tested using the method of example 1 and a conventional sebacic acid rust inhibitive agent was used as a comparison, and the result showed that no rust was formed on the filter paper with compound C as a metal rust inhibitive agent after 12 hours. After the observation time was prolonged to 48 hours, no rust was observed, and a large number of rust spots were formed on the filter paper using sebacic acid as a rust inhibitor after 48 hours, wherein the rust inhibitive performance of sebacic acid after 48 hours was compared with that of compound C as shown in fig. 3. Therefore, the compound C has a good rust-preventing effect when used as a metal rust inhibitor.

Example 4

Mixing 3.7g of N, N-dimethylformamide with 40mL of ethyl acetate to obtain a colorless transparent solution; to the above colorless transparent solution was added 9g of p-tert-butylbenzoic acid in one portion, stirred well at 30 ℃ for 2 hours until all the solid was dissolved, and the solvent was drained under reduced pressure at 40 ℃ while the mixture was stirred rapidly to give a white crystalline solid as compound D.

Compound D structure was characterized by nuclear magnetic resonance and the data obtained were as follows:

¹H-NMR(300MHz,CDCl₃,25℃,δ)：11.61(s,1H),8.04(s,1H),7.99(d,2H),7.41(d,2H),2.89(s,3H),2.83(s,3H),1.27(s,9H)。

¹³C-NMR(75MHz,CDCl₃,25℃,δ)：170.5,163.4,156.8,129.9,127.4,125.3,36.7,35.0,31.6,31.0.

the rust inhibitive performance of compound D was tested using the method of example 1 and a conventional sebacic acid rust inhibitive agent was used as a comparison, and the result showed that no rust was formed on the filter paper with compound D as a metal rust inhibitive agent after 12 hours. After the observation time was prolonged to 48 hours, no rust was found, and a large number of rust spots were formed on the filter paper using sebacic acid as a rust inhibitor after 48 hours, wherein the rust inhibitive performance of sebacic acid after 48 hours was compared with that of compound D as shown in fig. 4. Therefore, the compound D has a good rust-preventing effect when used as a metal rust inhibitor.

Example 5

Mixing 4.4g of N, N-dimethylacetamide with 40mL of ethyl acetate to obtain a colorless transparent solution; to the above colorless transparent solution was added 9g of p-tert-butylbenzoic acid in one portion, stirred well at 30 ℃ for 2 hours until all the solid was dissolved, and the solvent was drained under reduced pressure at 40 ℃ while the mixture was stirred rapidly to give a white crystalline solid as compound E.

Compound E was structurally characterized by nuclear magnetic resonance and the data obtained were as follows:

¹H-NMR(300MHz,CDCl₃,25℃,δ)：11.56(s,1H),7.98(d,2H),7.40(d,2H),2.93(s,3H),2.90(s,3H),2.07(s,3H),1.27(s,9H)。

¹³C-NMR(75MHz,CDCl₃,25℃,δ)：171.6,170.1,156.7,129.8,127.54,125.2,38.0,35.3,35.0,31.0,21.1.

the rust inhibitive performance of compound E was tested using the method of example 1 and a conventional sebacic acid rust inhibitive agent was used as a comparison, and the result showed that no rust was formed on the filter paper with compound E as a metal rust inhibitive agent after 12 hours. After the observation time was prolonged to 48 hours, no rust was observed, and a large number of rust spots were formed on the filter paper using sebacic acid as a rust inhibitor after 48 hours, wherein the rust inhibitive performance of sebacic acid after 48 hours was compared with that of compound E as shown in fig. 5. Therefore, the compound E has a good rust-preventing effect when used as a metal rust inhibitor.

Example 6

Mixing 6.5g of 1, 3-dimethyl propylene urea with 40mL of ethyl acetate to obtain a colorless transparent solution; to the above colorless transparent solution was added 9g of p-tert-butylbenzoic acid in one portion, stirred well at 30 ℃ for 2 hours until all the solid was dissolved, and the solvent was drained under reduced pressure at 40 ℃ while the mixture was stirred rapidly to give a white crystalline solid as compound F.

Compound F was structurally characterized by nuclear magnetic resonance and the data obtained were as follows:

¹H-NMR(300MHz,CDCl₃,25℃,δ)：10.95(s,1H),7.87(d,2H),7.28(d,2H),3.06(t,4H),2.79(s,6H),1.77(q,2H),1.17(s,9H)。

¹³C-NMR(75MHz,CDCl₃,25℃,δ)：169.6,157.1,156.4,129.7,127.6,125.1,47.7,35.7,34.9,31.0,21.8.

the rust inhibitive performance of compound F was tested using the method of example 1 and a conventional sebacic acid rust inhibitive agent was used as a comparison, and the result showed that no rust was formed on the filter paper with compound F as a metal rust inhibitive agent after 12 hours. After the observation time was prolonged to 48 hours, no rust was observed, and a large number of rust spots were formed on the filter paper using sebacic acid as a rust inhibitor after 48 hours, wherein the rust inhibitive performance of sebacic acid after 48 hours was compared with that of compound F as shown in fig. 6. Therefore, the compound F has a good rust-preventing effect when used as a metal rust inhibitor.

Example 7

Mixing 5.8g of 1, 3-dimethyl-2-imidazolidinone with 40mL of ethyl acetate to obtain a colorless transparent solution; to the above colorless transparent solution was added 9G of p-tert-butylbenzoic acid in one portion, stirred well at 50 ℃ for 2 hours until all the solid was dissolved, and the solvent was drained under reduced pressure at 40 ℃ while the mixture was stirred rapidly to give a white crystalline solid as compound G.

Compound G was structurally characterized by nuclear magnetic resonance and the data obtained were as follows:

¹H-NMR(300MHz,CDCl₃,25℃,δ)：10.64(s,1H),7.96(d,2H),7.39(d,2H),3.20(t,4H),2.72(s,6H),1.26(s,9H)。

¹³C-NMR(75MHz,CDCl₃,25℃,δ)：170.0,162.3,156.7,129.9,127.4,125.2,45.0,35.0,31.3,31.0.

the rust inhibitive performance of compound G was tested using the method of example 1 and a conventional sebacic acid rust inhibitive agent was used as a comparison, and the result showed that no rust was formed on the filter paper with compound G as a metal rust inhibitive agent after 12 hours. After the observation time was prolonged to 48 hours, no rust was still found, and a large number of rust spots were formed on the filter paper using sebacic acid as a rust inhibitor after 48 hours, wherein the rust inhibitive performance of sebacic acid after 48 hours was compared with that of compound G as shown in fig. 7. Therefore, the compound G has a good rust-preventing effect when used as a metal rust inhibitor.

As is clear from the above examples, the p-tert-butylbenzoic acid derivative provided by the present invention has a good rust-preventing effect as a metal rust inhibitor.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.