Nitrogen-containing multipurpose metal corrosion inhibitor and preparation method thereof

Abstract

The invention relates to the technical field of metal corrosion inhibitors, in particular to a nitrogen-containing multipurpose metal corrosion inhibitor and a preparation method thereof. The preparation method comprises the following step: carrying out ring-opening reaction on a nitrogen-containing substance and an epoxy structure substance to obtain the corrosion inhibitor. According to the preparation method, the nitrogen-containing substance and the epoxy structure substance are subjected to the ring-opening reaction, the corrosion inhibitor with excellent performance is formed, the route is easy to implement, and the cost is low. The prepared corrosion inhibitor can achieve the protection effect on various metals under the condition of low addition amount, other corrosion inhibitors or anti-rust agents do not need to be additionally added, and the corrosion inhibitor can be used for corrosion inhibition of semi-synthetic metal working fluids, emulsified metal working fluids and oily metal working fluids.

Description

Technical Field

[0001] The invention relates to the technical field of metal corrosion inhibitors, and in particular to a nitrogen-containing multi-purpose metal corrosion inhibitor and a preparation method thereof. Background Art

[0002] Metalworking fluid is a composite system containing multiple components. It plays an important role in workpiece processing. Its main functions include cooling, lubrication, washing and rust prevention. It must be stable, safe and environmentally healthy.

[0003] One of the main functions of metalworking fluids is to provide protection for metals. Corrosion inhibitors play a vital role in metalworking fluids, protecting metal surfaces by reducing metal corrosion rates and improving the quality and performance of metal parts after processing. Corrosion inhibitors can also effectively avoid hydrogen embrittlement and pitting corrosion, ensuring safety during metal processing.

[0004] Nitrogen-containing corrosion inhibitors such as benzotriazole (BTA) and its derivatives have excellent protective properties for metals. The N atoms in their structures can interact with metal ions and form a protective film on the metal surface. This film forms a complex with the ions on the metal surface through chemical adsorption, thereby protecting the metal from corrosion. BTA-type corrosion inhibitors are widely used in metalworking fluids, mainly for copper corrosion inhibitors, and can also be used to protect other types of metals (iron, aluminum).

[0005] However, the amount of benzotriazole added is relatively large, resulting in relatively high cost, and its solubility is poor, and it will encounter the problem of difficulty in compounding when used in water-based or oil-rich cutting fluids. It has been reported that benzotriazole can be used for the protection of iron or aluminum alloys after combining with a silane coupling agent, but its application range is limited, mainly using the product after combining benzotriazole with a silane coupling agent as a coating material, which is not suitable for metalworking fluid systems. The Chinese invention patent with publication number CN115161643A prepares a nano-silicon corrosion inhibitor containing benzotriazole that has excellent protective performance for copper and aluminum alloys and a stable structure by reacting a silane coupling agent with benzotriazole, and then adding aminopropyltrimethoxysilane and tetraethoxysilane. However, this type of nano-silicon corrosion inhibitor containing a silane coupling agent structure can only be used for metalworking fluids of a fully synthetic system, and its silane coupling agent structure will gradually aggregate during use, resulting in instability of the processing fluid system and ultimately failure. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a nitrogen-containing multi-purpose metal corrosion inhibitor suitable for semi-synthetic, emulsified and oily metal working fluids and a preparation method thereof.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a nitrogen-containing multi-purpose metal corrosion inhibitor, comprising the following steps: a nitrogen-containing substance and an epoxy structure substance undergo a ring-opening reaction to obtain a corrosion inhibitor.

[0008] Another technical solution adopted by the present invention is: the nitrogen-containing multi-purpose metal corrosion inhibitor is prepared by the preparation method of the above-mentioned nitrogen-containing multi-purpose metal corrosion inhibitor.

[0009] The beneficial effects of the present invention are as follows: the preparation method of the nitrogen-containing multi-purpose metal corrosion inhibitor of the present invention utilizes a nitrogen-containing substance and an epoxy structure substance to undergo a ring-opening reaction to form a corrosion inhibitor with excellent performance, and the route is simple to implement and has low cost. The prepared corrosion inhibitor can achieve a protective effect on a variety of metals at a relatively low addition amount, without the need to add other corrosion inhibitors or rust inhibitors, and can be used for corrosion inhibition of semi-synthetic metalworking fluids, emulsified metalworking fluids, and oily metalworking fluids. DETAILED DESCRIPTION

[0010] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes.

[0011] A method for preparing a nitrogen-containing multi-purpose metal corrosion inhibitor comprises the following steps: a nitrogen-containing substance and an epoxy structure substance undergo a ring-opening reaction to obtain the corrosion inhibitor.

[0012] From the above description, it can be seen that the beneficial effects of the present invention are: triazole corrosion inhibitors have excellent performance and can be better applied to metalworking fluids through reasonable design to ensure excellent performance, wide application range, and stability and reliability during use.

[0013] The present invention utilizes the nucleophilicity of nitrogen to open the epoxy structure. This route is simple to implement and has low cost. A novel corrosion inhibitor with excellent performance is formed. The corrosion protection of copper and aluminum alloys can be achieved at a relatively low addition amount. It also has excellent rust protection function for iron without the need to add other corrosion inhibitors or rust inhibitors. The corrosion inhibitor can be used in semi-synthetic metalworking fluids, emulsified metalworking fluids and oily metalworking fluids, and has a wide range of uses.

[0014] Furthermore, the nitrogen-containing substance is an azole compound.

[0015] Furthermore, the nitrogen-containing substance includes at least one of benzotriazole, 1,2,3-triazole, 1,2,4-triazole, imidazole and benzimidazole.

[0016] Furthermore, the epoxy structure substance is glycidyl ether.

[0017] Furthermore, the epoxy structure substance includes at least one of phenyl glycidyl ether, alkyl glycidyl ether, cycloalkyl glycidyl ether and polyoxyethylene glycidyl ether.

[0018] From the above description, it can be seen that the glycidyl ethers and azole compounds mentioned above have great price advantages in the market and are relatively low in cost. The scope of use can be regulated by the type of epoxy structure material selected. The selection of glycidyl ethers containing alkyl chains or long chains can increase oil solubility, and the selection of polyoxyethylene glycidyl ether can increase water solubility.

[0019] Furthermore, the method specifically comprises the following steps: dissolving the nitrogen-containing substance in an alkaline solution, and then cooling to room temperature to obtain a first reaction liquid; and dropping the epoxy structure substance into the first reaction liquid to perform a ring-opening reaction to obtain a corrosion inhibitor.

[0020] From the above description, it can be seen that the preparation process of the present invention is simple, and only needs to control the feeding rate and heating, without the need for catalysts, special solvents or special processes, and the reaction is thorough and pollution-free, and no subsequent purification steps are required.

[0021] Furthermore, the alkaline solution includes at least one of a sodium hydroxide solution, a potassium hydroxide solution and a sodium carbonate solution.

[0022] From the above description, it can be seen that the alkaline solution deprotonates the nitrogen heterocycle to promote the efficiency of the nucleophilic attack.

[0023] Furthermore, the reaction temperature of the ring-opening reaction is 50-80°C.

[0024] From the above description, it can be seen that the present invention controls the reaction thoroughly by limiting the reaction temperature. If the reaction temperature is too low, the reaction rate is low, and if it is too high, there will be more polymerization reactions in the reaction product.

[0025] Furthermore, the reaction time of the ring-opening reaction is 3 to 5 h.

[0026] Furthermore, the equivalent ratio of the nitrogen-containing substance to the alkali in the alkaline solution is 1:1 to 1:1.5.

[0027] Preferably, the equivalent ratio of the nitrogen-containing substance to the alkali in the alkaline solution is 1:1 to 1:1.2.

[0028] From the above description, it can be seen that adding 10% to 20% more alkali in the present invention can promote a more thorough reaction.

[0029] Furthermore, the equivalent ratio of the nitrogen-containing substance to the epoxy structure substance is 1:1~1:1.5.

[0030] Preferably, the equivalent ratio of the nitrogen-containing substance to the epoxy structure substance is 1:1 to 1:1.1.

[0031] From the above description, it can be seen that the ring-opened epoxy will generate hydroxyl groups and open the excess epoxy structure to produce a slight polymerization reaction. The epoxy structure material can be appropriately excessive to increase oil solubility or water solubility.

[0032] Another technical solution adopted by the present invention is: the nitrogen-containing multi-purpose metal corrosion inhibitor is prepared by the preparation method of the above-mentioned nitrogen-containing multi-purpose metal corrosion inhibitor.

[0033] Embodiment 1 of the present invention is: a method for preparing a nitrogen-containing multi-purpose metal corrosion inhibitor, comprising the following steps: dissolving 4 g of sodium hydroxide in 30 g of water to obtain a sodium hydroxide solution; then dissolving 6.9 g of 1,2,4-triazole in the sodium hydroxide solution to obtain a first reaction liquid; after the first reaction liquid is cooled to room temperature, 15 g of phenyl glycidyl ether is slowly added dropwise to the above solution through a dropping funnel while stirring, and after mixing, the system temperature is raised to 55°C by water-insulated heating and stirred for 4 hours, and finally the oily product is separated by a separatory funnel to obtain a corrosion inhibitor 1.

[0034] The corrosion inhibitor designed in the present invention is suitable for semi-synthetic, emulsified or oily metalworking fluids. Since oily metalworking fluids have good protection for metals, they cannot reflect the performance of the corrosion inhibitor in the present invention, so only the test results of emulsified metalworking fluids are provided in the test examples.

[0035] The formula of the metalworking fluid control example uses phosphate as an aluminum corrosion inhibitor, benzotriazole as a copper corrosion inhibitor, and sebacic acid as an iron rust inhibitor. The formula is shown in Table 1.

[0036] Table 1

[0037] Metalworking fluid test example: Only the corrosion inhibitor 1 prepared in Example 1 of the present invention was used as a metal corrosion inhibitor, and other additives with main functions were removed. The formula is shown in Table 2.

[0038] Table 2

[0039] The above metalworking fluid control example and metalworking fluid test example were tested, and the test results are shown in Table 3.

[0040] Table 3

[0041] It can be seen from the above results that the corrosion inhibitor in the present invention can be smoothly compounded into the emulsified cutting fluid and realize the protective function for metals. Corrosion inhibitor 1 is obtained by the reaction of triazole and phenyl propylene oxide. The combination has excellent protective effects on both copper and aluminum, and can greatly reduce the complexity of the formulation. In addition, the corrosion inhibitor has certain protective properties for iron metals, but dicarboxylic acids still need to be added in actual use.

[0042] Embodiment 2 of the present invention is: a method for preparing a nitrogen-containing multi-purpose metal corrosion inhibitor, comprising the following steps: dissolving 4.4 g of sodium hydroxide in 40 g of water to obtain a sodium hydroxide solution; then dissolving 11.9 g of benzotriazole in the sodium hydroxide solution to obtain a first reaction liquid; after the first reaction liquid is cooled to room temperature, 24.5 g of dodecyl glycidyl ether is slowly added dropwise to the above solution through a dropping funnel while stirring, and after mixing, the system temperature is raised to 80°C and stirred for 5 hours by heating in a water bath, and finally the oily product is separated by a separatory funnel to obtain corrosion inhibitor 2.

[0043] Embodiment 3 of the present invention is: a method for preparing a nitrogen-containing multi-purpose metal corrosion inhibitor, the steps of which are as follows: dissolve 4.4 g of sodium hydroxide in 10 g of water to obtain a sodium hydroxide solution; then dissolve 11.9 g of imidazole in the sodium hydroxide solution to obtain a first reaction liquid; after the first reaction liquid is cooled to room temperature, slowly add 6.8 g of polyoxyethylene bis(glycidyl ether) (epoxy value 0.4 mol / 100 g) to the above solution through a dropping funnel while stirring, and after mixing, heat the system to 60°C and stir for 3 hours to finally obtain a water-soluble corrosion inhibitor 3.

[0044] Embodiment 4 of the present invention is: The only difference between Example 4 and Example 3 is that the nitrogen-containing substance is 10g 1,2,3-triazole and 3g benzimidazole, the epoxy structure substance is 5g cycloalkyl glycidol and 2g polyoxyethylene bis(glycidyl ether), and the alkaline solution is potassium hydroxide solution.

[0045] Embodiment 5 of the present invention is: using the nitrogen-containing multi-purpose metal corrosion inhibitor prepared in Embodiment 1.

[0046] In summary, the nitrogen-containing multi-purpose metal corrosion inhibitor and the preparation method thereof provided by the present invention have the following advantages: 1. The preparation method is simple, no catalyst is required, and the cost is low.

[0047] 2. This corrosion inhibitor can achieve corrosion protection for copper and aluminum alloys at a relatively low addition amount, and has excellent anti-rust protection function for iron, with excellent performance.

[0048] 3. This corrosion inhibitor can be used in semi-synthetic metalworking fluids, emulsified metalworking fluids and oily metalworking fluids, and has a wide range of uses.

[0049] 4. Determine the concentration of water in the reactants according to the reaction products. If the reaction products are insoluble in water, water accounts for about 50% of the overall reaction mixture, and liquid separation is performed later. If the product is water-soluble, the water content in the final product is about 30% to ensure the concentration of the effective substance and ease of use.

[0050] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the specification of the present invention, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a nitrogen-containing multi-purpose metal corrosion inhibitor, characterized in that: The method comprises the following steps: a nitrogen-containing substance and an epoxy structure substance undergo a ring-opening reaction to obtain a corrosion inhibitor.

2. The method for preparing the nitrogen-containing multi-purpose metal corrosion inhibitor according to claim 1, characterized in that: The nitrogen-containing substance is an azole compound.

3. The method for preparing the nitrogen-containing multi-purpose metal corrosion inhibitor according to claim 2, characterized in that: The nitrogen-containing substance includes at least one of benzotriazole, 1,2,3-triazole, 1,2,4-triazole, imidazole and benzimidazole.

4. The method for preparing the nitrogen-containing multi-purpose metal corrosion inhibitor according to claim 1, characterized in that: The epoxy structure substance is glycidyl ether.

5. The method for preparing the nitrogen-containing multi-purpose metal corrosion inhibitor according to claim 4, characterized in that: The epoxy structure substance includes at least one of phenyl glycidyl ether, alkyl glycidyl ether, cycloalkyl glycidyl ether and polyoxyethylene glycidyl ether.

6. The method for preparing the nitrogen-containing multi-purpose metal corrosion inhibitor according to claim 1, characterized in that: The specific steps include: The nitrogen-containing substance is dissolved in an alkaline solution and then cooled to room temperature to obtain a first reaction solution; the epoxy structure substance is added dropwise to the first reaction solution to perform a ring-opening reaction to obtain a corrosion inhibitor.

7. The method for preparing the nitrogen-containing multi-purpose metal corrosion inhibitor according to claim 6, characterized in that: The reaction temperature of the ring-opening reaction is 50-80°C.

8. The method for preparing the nitrogen-containing multi-purpose metal corrosion inhibitor according to claim 6, characterized in that: The equivalent ratio of the nitrogen-containing substance to the alkali in the alkaline solution is 1:1 to 1:1.

5.

9. The method for preparing the nitrogen-containing multi-purpose metal corrosion inhibitor according to claim 6, characterized in that: The equivalent ratio of the nitrogen-containing substance to the epoxy structure substance is 1:1 to 1:1.

5.

10. A nitrogen-containing multi-purpose metal corrosion inhibitor prepared by the method for preparing a nitrogen-containing multi-purpose metal corrosion inhibitor according to any one of claims 1 to 9.

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