A silicon-based corrosion inhibitor and defoamer for high-temperature nitric acid pickling solution and its preparation method

Abstract

The present invention relates to a silicon-based corrosion inhibitor and defoamer for high-temperature nitric acid washing solution. The corrosion inhibitor and defoamer is obtained by polymerization using raw materials including ethylenediaminetetraethanol, dichlorodimethylsilane, diphenyldichlorosilane, N,N-dihydroxyethylaniline, triethylenetetramine, and petroleum ether. The finally obtained silicon-based corrosion inhibitor segment has an organosilicon group with excellent oxidation resistance, and the end groups are mainly amino groups and hydroxyl groups with excellent metal-binding ability. The final product has strong high-temperature oxidation resistance and is used in the corrosion inhibition system of highly oxidizing high-temperature nitric acid solution, with excellent corrosion inhibition effect, and the corrosion inhibition rate can reach more than 98%. Moreover, the silicon-based corrosion inhibitor product of the present invention also has a certain defoaming function, combining the dual effects of a high-temperature nitric acid corrosion inhibitor and a defoamer.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical products, and particularly relates to a silicon-based corrosion inhibitor and defoamer for high-temperature nitric acid pickling solution and a preparation method thereof. Background Art

[0002] Currently, before metal painting, pickling is generally required to remove the surface oxide film to enhance the adhesion effect of painting. To improve pickling efficiency, normal-temperature pickling processes are rarely used now, and medium-high temperature pickling methods are mostly adopted. Medium temperature generally refers to 60 - 80°C, and high-temperature pickling generally refers to 85 - 95°C. The higher the temperature, the faster the pickling speed, and the more thorough the removal of the oxide film, and the better the pickling effect. Medium-high temperature pickling generally uses nitric acid solution. Especially for high-concentration nitric acid solution (30% and above), due to its strong oxidizing property, especially the oxidation ability during high-temperature pickling, general corrosion inhibitors are easily oxidized and deteriorated by nitric acid, resulting in the loss of corrosion inhibition ability, accelerating the corrosion of the metal substrate, and causing metal waste. Although some corrosion inhibitors with relatively large molecules have been developed in recent years, such as

[0003] CN202110032002.9, but it is still mostly used in the environment of medium-temperature and low-concentration nitric acid, and it is difficult to adapt to the process of high-temperature and high-concentration nitric acid pickling at 90 - 95°C. For general normal-temperature pickling processes, there are many types of corrosion inhibitors available, and the effects are also good. However, as the temperature increases, the internal boiling of the solution and the enhanced oxidation ability of nitric acid make it difficult for conventional corrosion inhibitors to stably adsorb on the surface of the metal substrate to achieve the purpose of corrosion inhibition. Conventional C-C chain segments are prone to oxidation decomposition in the nitric acid environment at 90 - 95°C due to poor high-temperature oxidation resistance, thereby reducing the corrosion inhibition performance or even failing. Only chain segments with excellent high-temperature oxidation resistance can meet the application requirements. At the same time, during the pickling process, due to the presence of some cleaning agents in the pickling tank, the pickling solution is prone to foaming and overflowing, and generally, an additional defoamer needs to be added to inhibit foam generation. Summary of the Invention

[0004] To solve the above problems, the present invention uses a silicon-based chain segment with excellent high-temperature oxidation resistance as the functional chain segment of the corrosion inhibitor. Through segmented synthesis, a corrosion inhibitor product is prepared with a silicon-based main chain and hydroxyl and amino groups on the side chains. This corrosion inhibition and defoaming agent uses ethylenediaminetetraethanol, dichlorodimethylsilane, diphenyldichlorosilane, N,N-dihydroxyethylaniline, triethylenetetramine, and petroleum ether as raw materials for polymerization. The finally obtained silicon-based corrosion inhibitor chain segment has an organosilicon group with excellent oxidation resistance, and the end groups are mainly amino and hydroxyl groups with excellent metal-binding ability. The final product has strong high-temperature oxidation resistance and is used in the corrosion inhibition system of strongly oxidizing high-temperature nitric acid solution (90-95°C), with excellent corrosion inhibition effect, and the corrosion inhibition rate can reach more than 98%. Moreover, the silicon-based corrosion inhibitor product of the present invention also has a certain defoaming function, combining the dual functions of a high-temperature nitric acid corrosion inhibitor and a defoaming agent.

[0005] The present invention relates to a silicon-based corrosion inhibition and defoaming agent, which is obtained by carrying out a polymerization reaction using raw materials including ethylenediaminetetraethanol, dichlorodimethylsilane, diphenyldichlorosilane, N,N-dihydroxyethylaniline, triethylenetetramine, and petroleum ether.

[0006] Among them, the boiling range of the petroleum ether is 60-90°C.

[0007] The raw material composition of the silicon-based corrosion inhibition and defoaming agent includes, in terms of mole fraction:

[0008]

[0009]

[0010] The raw materials also include petroleum ether, and the dosage is 1.5-1.8 times the total mass of the above monomer raw materials;

[0011] In addition, the raw materials also include a catalyst and deionized water.

[0012] Furthermore, the catalyst is potassium hydroxide or sodium hydroxide, and the dosage is 1-3% of the mass of dichlorodimethylsilane.

[0013] Furthermore, a certain amount of deionized water is added to dissolve the synthesized product into an aqueous solution with a solid content of 55-60% by adding deionized water.

[0014] The preparation method of the silicon-based corrosion inhibition and defoaming agent includes the following steps:

[0015] A. Add the formulated amount of petroleum ether and ethylenediaminetetraethanol to the reaction kettle, stir and mix evenly at room temperature, and then add the formulated amount of dichlorodimethylsilane and diphenyldichlorosilane, and stir evenly;

[0016] B. Then add the formulated amount of catalyst to the reaction kettle, gradually raise the temperature to 60-65°C, and carry out a heat preservation reaction;

[0017] C. Sampling and testing. When the viscosity of the system reactants reaches 350 - 420 mPa·s, add the formulated amount of N,N - dihydroxyethylaniline and triethylenetetramine into the reaction kettle for chain - extension and end - capping reactions, and continue to keep the temperature at 60 - 65°C for the reaction.

[0018] D. When the viscosity of the system reactants reaches 900 - 960 mPa·s, stop the reaction, gradually raise the temperature to 90 - 100°C and reduce the pressure to remove the solvent to obtain a liquid product.

[0019] E. Add deionized water, and the resulting aqueous solution is the silicon - based corrosion inhibitor and defoamer product.

[0020] Preferably, in step D, after removing the solvent under reduced pressure, a liquid product with a volatile content lower than 2 wt% is obtained; the vacuum degree is controlled at - 0.096 Mpa to - 0.098 Mpa.

[0021] Preferably, in step E, add deionized water to dissolve the obtained product into an aqueous solution with a solid content of 55 - 60%, and thus the silicon - based corrosion inhibitor and defoamer product is obtained.

[0022] The present invention also relates to the application of the silicon - based corrosion inhibitor and defoamer as described above or the silicon - based corrosion inhibitor and defoamer obtained by the described preparation method in a high - temperature nitric acid pickling solution; the use temperature of the high - temperature nitric acid pickling solution is 90 - 95°C.

[0023] For example, a preparation method of a silicon - based corrosion inhibitor and defoamer includes the following steps:

[0024] A. Add the formulated amount of petroleum ether and ethylenediaminetetraethanol into the reaction kettle. After stirring and mixing evenly at room temperature, add the formulated amount of dichlorodimethylsilane and diphenyldichlorosilane, and stir evenly.

[0025] B. Then add the formulated amount of catalyst into the reaction kettle, and gradually raise the temperature to 60 - 65°C for heat - preservation reaction.

[0026] C. Sampling and testing. When the viscosity of the system reactants reaches 350 - 420 mPa·s, add the formulated amount of N,N - dihydroxyethylaniline and triethylenetetramine into the reaction kettle for chain - extension and end - capping reactions, and continue to keep the temperature at 60 - 65°C for a period of time for the reaction.

[0027] D. When the viscosity of the system reactants reaches 900 - 960 mPa·s, stop the reaction, gradually raise the temperature to 90 - 100°C and reduce the pressure to remove the solvent, obtaining a liquid product with a volatile content lower than 2 wt%, and the vacuum degree is controlled at - 0.096 Mpa to - 0.098 Mpa.

[0028] E. Add an appropriate amount of deionized water to dissolve the above product into an aqueous solution with a solid content of 55-60% to obtain the silicone-based corrosion inhibitor and defoamer product of the present invention.

[0029] The obtained product has a uniform viscous liquid appearance, and the pH is 8.5-9.5.

[0030] Advantages of the present invention:

[0031] The present invention uses a silicone-based chain segment with excellent high-temperature oxidation resistance as the functional chain segment of the corrosion inhibitor, and prepares a corrosion inhibitor product with a silicone-based main chain and hydroxyl and amino side chains through segmented synthesis. The corrosion inhibitor and defoamer uses ethylenediaminetetraethanol, dichlorodimethylsilane, diphenyldichlorosilane, N,N-dihydroxyethylaniline, triethylenetetramine, and petroleum ether as raw materials for polymerization; first, the alcohol hydroxyl groups of ethylenediaminetetraethanol react with dichlorodimethylsilane and diphenyldichlorosilane under the action of a catalyst to obtain an intermediate capped with organosilicon, and then it reacts with N,N-dihydroxyethylaniline and triethylenetetramine for chain extension and capping reactions. Finally, the obtained silicone-based corrosion inhibitor compound chain segment has an organosilicon group with excellent oxidation resistance, and its end groups are mainly amino and hydroxyl groups with excellent metal-binding ability. The final product has strong high-temperature oxidation resistance and excellent binding force with the metal surface. It is used in the corrosion inhibition system of a strongly oxidizing high-temperature nitric acid solution (90-95°C), and the corrosion inhibition effect is excellent, and the corrosion inhibition rate can reach more than 98%. Moreover, the silicone-based corrosion inhibitor product of the present invention also has a certain defoaming function of organosilicon, and has the dual functions of a nitric acid high-temperature corrosion inhibitor and a defoamer. Specific embodiments

[0032] To facilitate the understanding of the present invention, various exemplary embodiments of the present invention are now described in detail. This detailed description should not be regarded as a specific limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0033] Petroleum ether is an industrial-grade raw material with a boiling range of 60-90°C and is purchased from Shandong Changhui Chemical Co., Ltd.; the rest of the raw materials are all commonly used commercially available raw materials.

[0034] Example 1

[0035] The raw material composition of the silicone-based corrosion inhibitor and defoamer includes, in terms of mole fraction:

[0036]

[0037] The dosage of petroleum ether is 1.5 times the total mass of the above monomer raw materials;

[0038] The catalyst is potassium hydroxide, and the dosage is 1% of the mass of dichlorodimethylsilane.

[0039] The amount of deionized water is such that the synthesized product is dissolved in deionized water to form an aqueous solution with a solid content of 55%.

[0040] A preparation method of a silicon-based corrosion inhibitor and defoamer, comprising the following steps:

[0041] A. Add the formulated amounts of petroleum ether and ethylenediaminetetraethanol to a reaction kettle, stir and mix evenly at room temperature, then add the formulated amounts of dichlorodimethylsilane and diphenyldichlorosilane, and stir evenly;

[0042] B. Then add the formulated amount of catalyst to the reaction kettle, gradually raise the temperature to 65 °C and carry out a heat preservation reaction;

[0043] C. Take a sample for detection. When the viscosity of the reactants in the system reaches 375 mPa·s, add the formulated amounts of N,N-dihydroxyethylaniline and triethylenetetramine to the reaction kettle for end-capping reaction, and continue to carry out a heat preservation reaction at 65 °C for a period of time;

[0044] D. When the viscosity of the reactants in the system reaches 950 mPa·s, stop the reaction, gradually raise the temperature to 100 °C and reduce the pressure to remove the solvent, to obtain a liquid product with a volatile content of less than 2 wt%, and the vacuum degree is controlled at -0.098 Mpa;

[0045] E. Add deionized water to dissolve the above product into an aqueous solution with a corresponding solid content, which is the silicon-based corrosion inhibitor and defoamer product.

[0046] The obtained product has an appearance of a uniform viscous liquid, pH: 8.7.

[0047] Example 2

[0048] The raw material composition of the silicon-based corrosion inhibitor and defoamer includes, in terms of mole fraction:

[0049]

[0050]

[0051] The amount of petroleum ether is 1.6 times the total mass of the above monomer raw materials;

[0052] The catalyst is sodium hydroxide, and the amount used is 3% of the mass of dichlorodimethylsilane.

[0053] The amount of deionized water is such that the synthesized product is dissolved in deionized water to form an aqueous solution with a solid content of 58%.

[0054] The preparation method is the same as that of Example 1.

[0055] The obtained product has an appearance of a uniform viscous liquid, pH: 9.3.

[0056] Example 3

[0057] The raw material composition of the silicon-based corrosion inhibitor and defoamer includes, in terms of mole fractions:

[0058]

[0059] The amount of petroleum ether is 1.7 times the total mass of the above monomer raw materials;

[0060] The catalyst is potassium hydroxide, and the amount used is 2% of the mass of dichlorodimethylsilane.

[0061] The amount of deionized water is such that the synthesized product is dissolved in deionized water to form an aqueous solution with a solid content of 60%.

[0062] The preparation method is the same as that in Example 1.

[0063] The obtained product has an appearance of a uniform viscous liquid, pH: 9.

[0064] Example 4

[0065] The raw material composition of the silicon-based corrosion inhibitor and defoamer includes, in terms of mole fractions:

[0066]

[0067] Petroleum ether, and the amount used is 1.6 times the total mass of the above monomer raw materials;

[0068] The catalyst is potassium hydroxide or sodium hydroxide, and the amount used is 2% of the mass of dichlorodimethylsilane.

[0069] The amount of deionized water is such that the synthesized product is dissolved in deionized water to form an aqueous solution with a solid content of 59%.

[0070] The preparation method is the same as that in Example 1.

[0071] The obtained product has an appearance of a uniform viscous liquid, pH: 9.1.

[0072] Comparative Example 1: The product in Example 2 of CN202110032002.9 is used as Comparative Example 1;

[0073] Testing method for corrosion inhibition performance:

[0074] The corrosion inhibition rate is based on GB / T 18175-2000 "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotating Hanging Specimen Method". Among them, the washing solutions are tested with a nitric acid solution with a mass concentration of 30% and a nitric acid solution with a mass concentration of 40%. The added mass of the corrosion inhibitor is 0.5% of the mass of the nitric acid washing solution; the added amount of sodium dodecylbenzenesulfonate is 0.1% of the mass of the nitric acid washing solution; time: 72 h; washing solution temperature: 92 °C; specimen linear velocity: 0.35 m / s; specimen material: 20# carbon steel hanging specimen.

[0075] The application performance test results are shown in Table 1 below.

[0076] Table 1 Performance test data of examples and comparative examples

[0077]

[0078] From the comparison between Examples 1-4 and Comparative Example 1 in Table 1, it can be seen that with the help of the function of the silicon-based segment, the product of the present invention has excellent corrosion inhibition performance and defoaming performance during the cleaning process with nitric acid cleaning solution at 92 °C / 72 h. Although the product in Comparative Example 1 has good effects in medium-temperature and low-concentration nitric acid cleaning solutions, its corrosion inhibition performance in high-temperature and high-concentration nitric acid cleaning solutions is inferior to that of the product of the present invention, and it also has no defoaming effect.

[0079] Obviously, the above examples are only for illustration and are not intended to limit the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A silicon-based corrosion inhibitor and defoamer, characterized in that, The raw material composition includes, in terms of mole parts: Petroleum ether, with a dosage of 1.5 - 1.8 times the total mass of the above monomer raw materials; In addition, the raw materials also include a catalyst and deionized water; The reaction process is as follows: First, the alcohol hydroxyl groups of ethylenediamine tetraethanol undergo a chain extension reaction with dichlorodimethylsilane and diphenyldichlorosilane under the action of a catalyst to obtain an intermediate capped with silicone, and then it undergoes a chain extension and capping reaction with N,N - dihydroxyethylaniline and triethylenetetramine to finally obtain a silicone - based corrosion inhibitor and defoamer.

2. The silicon-based corrosion inhibitor and defoamer according to claim 1, wherein The boiling range of the petroleum ether is 60 - 90°C.

3. The silicone - based corrosion inhibitor and defoamer according to claim 1, further characterized in that the catalyst is potassium hydroxide or sodium hydroxide, and the dosage is 1 - 3% of the mass of dichlorodimethylsilane.

4. The silicone - based corrosion inhibitor and defoamer according to claim 1, further characterized in that a certain amount of deionized water is added to dissolve the synthesized product into an aqueous solution with a solid content of 55 - 60%.

5. The preparation method of a silicon-based corrosion inhibitor and defoamer according to any one of claims 1-4, characterized in that It includes the following steps: A. Add the formulated amount of petroleum ether and ethylenediamine tetraethanol to the reaction kettle, stir and mix evenly at room temperature, then add the formulated amount of dichlorodimethylsilane and diphenyldichlorosilane, and stir evenly; B. Then add the formulated amount of catalyst to the reaction kettle, gradually heat up to 60 - 65°C for heat - preservation reaction; C. Take samples for detection. When the viscosity of the reactants in the system reaches 350 - 420 mPa·s, add the formulated amount of N,N - dihydroxyethylaniline and triethylenetetramine to the reaction kettle for chain extension and capping reaction, and continue the heat - preservation reaction at 60 - 65°C; D. When the viscosity of the reactants in the system reaches 900 - 960 mPa·s, stop the reaction, gradually heat up to 90 - 100°C and remove the solvent under reduced pressure to obtain a liquid product; E. Add deionized water, and the obtained aqueous solution is the silicone - based corrosion inhibitor and defoamer product.

6. The preparation method of a silicon-based corrosion inhibitor and defoamer according to claim 5, characterized in that, In step D, after removing the solvent under reduced pressure, a liquid product with a volatile content of less than 2 wt% is obtained; the vacuum degree is controlled at - 0.096 Mpa to - 0.098 Mpa.

7. The preparation method of a silicon-based corrosion inhibitor and defoamer according to claim 5, characterized in that, In step E, add deionized water to dissolve the obtained product into an aqueous solution with a solid content of 55 - 60% to obtain the silicone - based corrosion inhibitor and defoamer product.

8. The application of the silicone - based corrosion inhibitor and defoamer according to any one of claims 1 - 4 or the silicone - based corrosion inhibitor and defoamer obtained by the preparation method according to any one of claims 5 - 7 in a high - temperature nitric acid pickling solution.

9. The application according to claim 8, wherein the use temperature of the high - temperature nitric acid pickling solution is 90 - 95°C.

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