A bio-based corrosion inhibitor, its preparation method and application

Abstract

The present invention discloses a bio-based corrosion inhibitor and its preparation method and application. The bio-based corrosion inhibitor provided by the present invention has the following structural formula: wherein, R is -C<subgt;12< / subgt;H<subgt;25< / subgt; or -C<subgt;16< / subgt;H<subgt;33< / subgt>. The preparation method includes the following steps: dissolving 5-hydroxymethylfurfural in dichloromethane, adding thionyl chloride, and obtaining chlorinated furfural after reaction; dissolving the chlorinated furfural in acetonitrile, adding dodecyl dimethyl tertiary amine or hexadecyl dimethyl tertiary amine, and obtaining the target product bio-based corrosion inhibitor after reaction; the novel bio-based corrosion inhibitor is prepared from bio-based furfural, has a wide range of raw material sources, a low use concentration, and excellent corrosion inhibition performance.

Description

Technical Field

[0001] The present invention relates to the technical field of corrosion inhibitors for metal anti-corrosion, and particularly to a novel bio-based corrosion inhibitor, a preparation method thereof, and an application thereof. Background Art

[0002] Corrosion not only causes serious economic losses but also triggers major disaster accidents. According to "Research on China's Corrosion Status and Control Strategy" released by the Chinese Academy of Engineering, the losses caused by corrosion in China exceed two trillion yuan every year, accounting for about 3.34% of the national GDP, exceeding the total losses of all natural disasters in a year. Therefore, developing simple and efficient anti-corrosion technologies has important practical significance.

[0003] Among many anti-corrosion technologies, corrosion inhibitors are widely used due to their simplicity and high efficiency. Traditional high-efficiency inorganic corrosion inhibitor products such as chromates and dichromates have been prohibited and phased out due to their toxicity to the human body and serious environmental pollution. Currently developed organic corrosion inhibitors such as benzotriazoles, benzimidazoles, thioureas, amines, and fatty acids have unsatisfactory anti-corrosion performance and may pollute the environment during use. To meet the needs of environmental protection and the green sustainable development strategy, corrosion inhibitors not only need to have stable and efficient anti-corrosion effects and safe and convenient usage methods, but also new slow-release agents should meet the requirements of green chemistry during the development process to reduce the impact of products on the environment. Developing novel green corrosion inhibitors from bio-based raw materials is an important development direction. Patent CN113293379A reports a corrosion inhibitor of Gardenia jasminoides Ellis fruit extract. The active ingredient of the corrosion inhibitor of Gardenia jasminoides Ellis fruit extract described in this invention is the water extract of Gardenia jasminoides Ellis fruit. The corrosion inhibitor in this invention can effectively slow down the corrosion of copper in sulfuric acid corrosion media within a certain temperature range. The corrosion inhibitor is easily obtained, the raw materials are abundant, and the components contained are natural, harmless, green, and environmentally friendly. Patent CN114645279A reports an application of rhamnolipid as an environmentally friendly microbial corrosion inhibitor. The rhamnolipid can be used as an environmentally friendly microbial corrosion inhibitor to inhibit microbial corrosion problems faced by metal materials during service. When rhamnolipid is added to the environment that can cause microbial corrosion at a concentration of 0.53 - 1.9 g / L, the results show that rhamnolipid, as an environmentally friendly microbial corrosion inhibitor, can not only inhibit metal corrosion itself but also effectively inhibit the corrosion of metal materials caused by environmental microorganisms, and has the characteristics of being green and environmentally friendly.

[0004] Currently, although there are reports on some bio-based corrosion inhibitors, there is still a lack of a bio-based corrosion inhibitor with a wide range of raw material sources, high efficiency, and environmental friendliness at low concentrations. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a novel bio-based corrosion inhibitor and its preparation method and application. The novel bio-based corrosion inhibitor is prepared from bio-based furfural as the raw material, which has a wide range of raw material sources, low usage concentration, and excellent corrosion inhibition performance.

[0006] To achieve this purpose, the present invention provides a novel bio-based corrosion inhibitor with the following structural formula:

[0007]

[0008] Among them, R is -C 12 H 25 or -C 16 H 33 .

[0009] The preparation method of the bio-based corrosion inhibitor of the present invention includes the following steps:

[0010] (1) Dissolve 5-hydroxymethylfurfural in dichloromethane, add thionyl chloride, and react to obtain chlorinated furfural;

[0011] (2) Dissolve the chlorinated furfural in acetonitrile, add dodecyl dimethyl tertiary amine or cetyl dimethyl tertiary amine, and react to obtain the target product bio-based corrosion inhibitor;

[0012] Taking R as -C 16 H 33 as an example, the synthesis route is as follows .

[0013] Furthermore, in the step (1), the molar ratio of 5-hydroxymethylfurfural to thionyl chloride is 1:1.5.

[0014] Furthermore, the reaction temperature in the step (1) is 0 °C, and the reaction time is 1 h.

[0015] Furthermore, in the step (2), the molar ratio of chlorinated furfural to dodecyl dimethyl tertiary amine is 1:1.5, and the molar ratio of chlorinated furfural to cetyl dimethyl tertiary amine is 1:1.5.

[0016] Furthermore, the reaction temperature in the step (2) is 80 °C, and the reaction time is 1 h.

[0017] Furthermore, the corrosion inhibitor is suitable for the anti-corrosion of steel in a neutral corrosion environment.

[0018] Furthermore, the usage concentration of the corrosion inhibitor is 5 - 500 ppm.

[0019] Furthermore, the usage concentration of the corrosion inhibitor is 10 - 50 ppm.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The molecular structure of the biobased corrosion inhibitor of the present invention contains oxygen atoms and nitrogen atoms, which can interact with the atoms on the metal surface to form a dense molecular protective film to exert the anti-corrosion performance. At the same time, the longer alkyl chains in the molecule can make the molecular protective film hydrophobic, further enhancing the anti-corrosion performance; its use concentration is low, it can effectively slow down the corrosion of metals in neutral corrosion media, and the raw materials of the corrosion inhibitor are easily obtained, the raw materials are abundant, the cost is low, and the components of the corrosion inhibitor are green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the NMR spectrum of the corrosion inhibitor used in Example 1.

[0022] Figure 2 is the comparison of the corrosion surfaces of the carbon steel sheets in Example 1 and the carbon steel sheets in Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0023] To facilitate the understanding of the present invention, the following examples are listed for the present invention. Those skilled in the art should understand that the said examples are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0024] Example 1

[0025] This example provides a novel biobased corrosion inhibitor, and its structural formula is

[0026] where R is -C 16 H 33 ,

[0027] The synthesis method of the biobased corrosion inhibitor of the present invention includes the following steps:

[0028] Step 1:

[0029]

[0030] Dissolve 1 g of 5-hydroxymethylfurfural in dichloromethane, add 1.5 times the molar equivalent of thionyl chloride at 0 °C, and continue the reaction for 1 h. Then add a sodium bicarbonate solution to quench, and perform extraction with dichloromethane and deionized water (1:1), add anhydrous magnesium sulfate for drying, and remove the solvent to obtain chlorinated furfural.

[0031] Step 2:

[0032]

[0033] 1 g of chlorofurfural was dissolved in acetonitrile and 1.5 times the molar equivalent of hexadecyldimethylamine was added. The mixture was reacted at 80°C for 1 h. After removing the solvent, the product was purified by chromatography using dichloromethane and methanol (10:1) to obtain R-C 16 H 33 Bio-based corrosion inhibitors.

[0034] The corrosion inhibitor was dissolved in a 3.5 wt% NaCl aqueous solution at a concentration of 500 ppm. Q235 carbon steel, polished with 2000# metallographic sandpaper, was then immersed in the inhibitor solution for 48 hours. Finally, the carbon steel was immersed in a 20% hydrochloric acid solution for 20 minutes. Surface rust was then removed with a brush, dried, and weighed. The corrosion inhibition efficiency was then calculated.

[0035] Example 2

[0036] This example used the bio-based corrosion inhibitor prepared in Example 1. It was dissolved in a 3.5 wt% NaCl aqueous solution at a concentration of 5 ppm. Q235 carbon steel, polished with 2000# metallographic sandpaper, was then immersed in the inhibitor solution for 48 hours. Finally, the steel was immersed in a 20% hydrochloric acid solution for 20 minutes. Surface rust was then removed with a brush, dried, and weighed. The corrosion inhibition efficiency was then calculated.

[0037] Example 3

[0038] This example used the bio-based corrosion inhibitor prepared in Example 1. It was dissolved in a 3.5 wt% NaCl aqueous solution at a concentration of 50 ppm. Q235 carbon steel, polished with 2000# metallographic sandpaper, was then immersed in the inhibitor solution for 48 hours. Finally, the carbon steel was immersed in a 20% hydrochloric acid solution for 20 minutes. Surface rust was then removed with a brush, dried, and weighed. The corrosion inhibition efficiency was then calculated.

[0039] Example 4

[0040] This example used the bio-based corrosion inhibitor prepared in Example 1. It was dissolved in a 3.5 wt% NaCl aqueous solution at a concentration of 30 ppm. Q235 carbon steel, polished with 2000# metallographic sandpaper, was then immersed in the inhibitor solution for 48 hours. Finally, the carbon steel was immersed in a 20% hydrochloric acid solution for 20 minutes. Surface rust was then removed with a brush, dried, and weighed. The corrosion inhibition efficiency was then calculated.

[0041] Example 5

[0042] This example uses the biobased corrosion inhibitor prepared in Example 1. The corrosion inhibitor was dissolved in a 3.5 wt% NaCl aqueous solution at a concentration of 10 ppm, and then Q235 carbon steel polished with 2000# metallographic sandpaper was immersed in the corrosion inhibitor solution for 48 h. Finally, the carbon steel was immersed in a 20% hydrochloric acid solution for 20 minutes, and then the surface rust was removed with a brush, dried and weighed to calculate the corrosion inhibition efficiency.

[0043] Example 6

[0044] This example provides a novel biobased corrosion inhibitor, in which R in the structural formula is -C 12 H 25 , and the preparation method is the same as that in Example 1.

[0045] The corrosion inhibitor was dissolved in a 3.5 wt% NaCl aqueous solution at a concentration of 50 ppm, and then Q235 carbon steel polished with 2000# metallographic sandpaper was immersed in the corrosion inhibitor solution for 48 h. Finally, the carbon steel was immersed in a 20% hydrochloric acid solution for 20 minutes, and then the surface rust was removed with a brush, dried and weighed to calculate the corrosion inhibition efficiency.

[0046] Example 7

[0047] This example uses the biobased corrosion inhibitor prepared in Example 6. The corrosion inhibitor was dissolved in a 3.5 wt% NaCl aqueous solution at a concentration of 10 ppm, and then Q235 carbon steel polished with 2000# metallographic sandpaper was immersed in the corrosion inhibitor solution for 48 h. Finally, the carbon steel was immersed in a 20% hydrochloric acid solution for 20 minutes, and then the surface rust was removed with a brush, dried and weighed to calculate the corrosion inhibition efficiency.

[0048] Comparative Example 1

[0049] In this comparative example, no novel biobased corrosion inhibitor was added, and Q235 carbon steel was directly immersed in a 3.5 wt% NaCl aqueous solution for 48 h. Finally, the carbon steel polished with 2000# metallographic sandpaper was immersed in a 20% hydrochloric acid solution for 20 minutes, and then the surface rust was removed with a brush, dried and weighed to calculate the corrosion inhibition efficiency.

[0050] Its experimental index of corrosion inhibition efficiency is:

[0051] Corrosion inhibition efficiency (%) = (1 - Δ W / Δ W 0) * 100%, where Δ W 0 and Δ W are the average weight losses of the steel sheets in the solutions without and with the corrosion inhibitor, respectively.

[0052] The test results are summarized in Table 1.

[0053] Table 1

[0054]

[0055] Analysis of the data in Table 1 shows that the biobased corrosion inhibitor described in the present invention has a low usage concentration. When the concentration of the corrosion inhibitor is 10 ppm, its corrosion inhibition efficiency reaches 97.5%. When the concentration of the corrosion inhibitor is greater than 50 ppm, its corrosion inhibition efficiency exceeds 99%. This indicates that the corrosion inhibitor has excellent corrosion inhibition performance and can effectively slow down the corrosion of metals in neutral corrosion media. Moreover, the raw materials of the corrosion inhibitor are easily obtained, abundant, and low in cost, and the components of the corrosion inhibitor are green and environmentally friendly.

[0056] From the attached Figure 2 specification, it can be seen that in Example 1, the biobased corrosion inhibitor added formed a corrosion protection film on the surface of the carbon steel, and no obvious corrosive substances were generated on the surface of the carbon steel after the corrosion experiment. In Comparative Example 1, due to the absence of a corrosion inhibitor, serious rusting occurred on the surface of the carbon steel. The above comparison results show that the biobased corrosion inhibitor provided in the present invention has excellent corrosion inhibition performance for carbon steel in neutral corrosion media.

[0057] The applicant declares that the present invention uses the above embodiments to illustrate the detailed method of the present invention, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A bio-based corrosion inhibitor, characterized in that, The structural formula is as follows: wherein, R is -C 12 H 25 or -C 16 H 33 .

2. The preparation method of the bio-based corrosion inhibitor according to claim 1, characterized in that, It includes the following steps: (1) Dissolve 5-hydroxymethylfurfural in dichloromethane, add thionyl chloride, and obtain chlorinated furfural after reaction; (2) Dissolve chlorinated furfural in acetonitrile, add dodecyl dimethyl tertiary amine or cetyl dimethyl tertiary amine, and obtain the target product biobased corrosion inhibitor after reaction.

3. The preparation method of the bio-based corrosion inhibitor according to claim 2, characterized in that, In the step (1), the molar ratio of 5-hydroxymethylfurfural to thionyl chloride is 1:1.

5.

4. The preparation method of the bio-based corrosion inhibitor according to claim 2, characterized in that, In the step (1), the reaction temperature is 0 °C and the reaction time is 1 h.

5. The preparation method of the bio-based corrosion inhibitor according to claim 2, wherein In the step (2), the molar ratio of chlorinated furfural to dodecyl dimethyl tertiary amine is 1:1.5, and the molar ratio of chlorinated furfural to cetyl dimethyl tertiary amine is 1:1.

5.

6. The preparation method of the bio-based corrosion inhibitor according to claim 2, characterized in that, In the step (2), the reaction temperature is 80 °C and the reaction time is 1 h.

7. Use of the bio-based corrosion inhibitor according to claim 1, characterized in that, The corrosion inhibitor is applicable to the anti-corrosion of steel in a neutral corrosion environment.

8. The application according to claim 7, wherein The usage concentration of the corrosion inhibitor is 5 - 500 ppm.

9. The application according to claim 7, wherein The usage concentration of the corrosion inhibitor is 10 - 50 ppm.

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