An environmentally friendly water-based high-efficiency rust inhibitor and its preparation method and application

Abstract

The invention belongs to the technical field of metal rust prevention, and specifically relates to an environmentally friendly water-based high-efficiency rust inhibitor and a preparation method and application thereof; the invention uses urea-containing monomers, amine monomers and (methyl) acrylate monomers as raw materials to obtain the environmentally friendly water-based high-efficiency rust inhibitor through Michael addition reaction; the rust inhibitor formed by the invention contains a polar group urea group, which is adsorbed on the metal surface; at the same time, it contains a long carbon chain hydrophobic hydrocarbon group, has oil solubility, strong wetting ability, isolates the contact between corrosive electrolyte and metal surface, and can form a protective film on the metal surface after dip coating, thereby achieving a high-efficiency rust prevention effect.

Description

Technical Field

[0001] The invention belongs to the technical field of metal rust prevention, and specifically relates to an environmentally friendly water-based high-efficiency rust inhibitor and a preparation method and application thereof. Background Art

[0002] The destruction or deterioration of metal materials due to various factors acting separately or together is called metal corrosion, and the most common form of corrosion is metal rust. Metal corrosion usually occurs in two ways, including chemical corrosion and electrochemical corrosion. The rust caused by the direct reaction of the surrounding medium with the metal surface is called chemical corrosion; when the metal material is in water or air with high humidity, a micro-battery will be formed on the surface, and the electrode reaction will cause rust, which is called electrochemical corrosion. Metal corrosion is usually electrochemical corrosion.

[0003] At present, the common methods of metal protection are: 1. Improve the nature of metals. According to different application fields, choose different materials, process metals that are more prone to corrosion into corrosion-resistant alloys, or directly add some suitable alloy elements to the metal materials to improve the material's corrosion resistance. 2. Form a protective covering layer to isolate the metal material from the corrosive medium, prevent the metal anode from reacting, and thus prevent the formation of a corrosion galvanic cell. 3. Add rust inhibitors. Rust inhibitors are also called corrosion inhibitors. When they exist in a corrosive medium environment at a suitable concentration, they can effectively prevent or reduce the corrosion rate of metal materials. The advantages of rust inhibitor protection technology are small dosage, quick effect, low cost, and easy use. At present, this technology has been widely used in machinery, chemical industry, energy, and metallurgy departments.

[0004] Existing water-based rust inhibitors are roughly divided into inorganic rust inhibitors and organic rust inhibitors. Inorganic rust inhibitors generally form an insoluble film layer on the metal surface to play an anti-rust role. The widely used inorganic rust inhibitors include nitrites, chromates, borates, molybdates, etc. However, nitrite is a recognized carcinogen in the industry, chromates will cause heavy metal pollution, and molybdates are expensive, so the application of inorganic flash rust inhibitors is limited. Commonly used organic rust inhibitors include monocarboxylic acids, dicarboxylic acid amides, etc. These rust inhibitors have the disadvantages of small molecules, poor stability, and single use cannot achieve the required anti-rust effect. Therefore, it is necessary to develop an environmentally friendly and efficient water-based organic rust inhibitor. Summary of the invention

[0005] In order to solve the above problems, the present invention discloses an environmentally friendly water-based high-efficiency rust inhibitor and a preparation method and application thereof.

[0006] The present invention uses urea-containing monomers, amine monomers and (methyl) acrylate monomers as raw materials to obtain an environmentally friendly water-based high-efficiency rust inhibitor through a Michael addition reaction. The rust inhibitor formed by the present invention contains a polar group urea group, which is adsorbed on the metal surface; it also contains a long carbon chain hydrophobic hydrocarbon group, has oil-soluble characteristics, strong wetting ability, isolates the contact between the corrosive electrolyte and the metal surface, and can form a protective film on the metal surface after dip coating, achieving a high-efficiency rust-proof effect.

[0007] To achieve the above object, the technical solution of the present invention is as follows: The present invention provides a method for preparing an environmentally friendly water-based high-efficiency rust inhibitor, comprising the following steps: adding an amine monomer to a solvent, stirring and heating to 25-90° C., first dripping an acrylate monomer, then dripping a urea-based monomer, keeping the temperature for reaction for 3-5 hours after the dripping, cooling and discharging the material, and rotary evaporating to obtain the water-based high-efficiency rust inhibitor. Preferably, stirring and heating to 40-60° C.

[0008] Furthermore, the molar ratio of the amine monomer, the acrylate monomer and the urea monomer is 1:1-2:1-3; and the mass ratio of the solvent to the amine monomer is 2-3:1.

[0009] Furthermore, the amine monomer is one or more of ethylamine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, propylamine, n-butylamine, isobutylamine, 1,5-pentanediamine, hexylamine, hexyldiamine, n-heptylamine, n-octylamine, 1-nonylamine, n-decylamine, diethylenetriamine, triethylenetetramine, pentaethylenetetramine, monoethanolamine, 3-propanolamine, monoisopropanolamine, and aniline.

[0010] Furthermore, the acrylic acid ester monomer is one or more of n-octyl acrylate, decyl acrylate, tetradecyl acrylate, n-octyl methacrylate, isooctyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, and tridecyl 2-methyl-2-acrylate.

[0011] Furthermore, the structure of the urea monomer is as follows: (1); or (2); Wherein, n is an integer from 1 to 5; X is O, NH or NR, wherein R is methyl or ethyl; Y is H or CH3.

[0012] Further, the urea-based monomer is one or more of ethyl imidazolone (meth) acrylate, ethyl imidazolone (meth) acrylamide, 1-[2-[[2-hydroxy-3-(2-allyloxy)propyl]amino]ethyl-2-imidazolone (CAS: 85356-84-9), 2-(2-oxo-1-imidazolidinyl)ethyl methacrylate (CAS: 86261-90-7), also known as N-(2-methacryloyloxyethyl)ethylene urea or 2-ureidoethyl methacrylate (referred to herein as WAMⅩ); N-[2-(2-oxo-1-imidazolidinyl)ethyl]methacrylamide (CAS: 3089-19-8), also known as methacrylamide ethylethylene urea.

[0013] Preferred urea-containing monomers include: ethyl 2-(2-oxo-1-imidazolidinyl)methacrylate, also known as ethyl 2-ureidomethacrylate (referred to herein as WAM X); N-[2-(2-oxo-1-imidazolidinyl)ethyl]methacrylamide (CAS: 3089-19-8).

[0014] Furthermore, the solvent is one or more of methanol, ethanol, cyclohexane, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, and N-methylpyridine.

[0015] The present invention also provides an environmentally friendly water-based high-efficiency rust inhibitor prepared by the above-mentioned preparation method.

[0016] The present invention also provides the use of the above-mentioned environmentally friendly water-based high-efficiency rust inhibitor in water-based cutting fluid.

[0017] The beneficial effects of the present invention are: The invention is environmentally friendly, highly efficient, requires little usage and has good stability.

[0018] The synthesis of the rust inhibitor of the present invention is carried out through the Michael addition reaction. The Michael addition reaction is a conjugated addition reaction between a conjugated unsaturated carbonyl compound, mainly including an electrophilic conjugated system such as aldehydes, ketones, esters, nitriles, amides, etc. and a donor providing a nucleophilic carbon anion. It is an important method for forming bonds such as CN, CC, CS, and CO. The present invention selects amines and unsaturated carboxylates to undergo Michael addition reaction to form CN bonds. The N atom in the polar group contains lone pairs of electrons. On the one hand, it combines with hydrogen protons to form cations. The van der Waals force between the cations and the metal forms physical adsorption to make the organic rust inhibitor adsorbed on the metal surface; on the other hand, the lone pairs of electrons form coordination bonds with the empty d orbitals of the metal atoms. The coordination bonds are chemical bonds with strong forces, which promote the organic rust inhibitor molecules to be firmly adsorbed on the metal surface.

[0019] The Michael addition reaction needs to be carried out under the catalysis of a base, which helps to form a more stable anionic nucleophile and promote the reaction. The appropriate base is selected according to the reaction activity. Commonly used bases include: pyridine, piperidine, potassium tert-butoxide, sodium ethoxide, sodium hydride, sodium amide, triethylamine and other organic bases. The addition amount is 2%-10% of the amount of amine monomer and acrylate monomer, preferably 2%-5%. If both reactants have high reactivity, a weaker base can also make the reaction proceed. Under specific conditions, for example, by controlling the amount of the highly active amine and the substrate at room temperature, the Michael addition reaction can be completed in a short time without a catalyst, and the yield is high.

[0020] The environmentally friendly and efficient water-based organic rust inhibitor provided by the present invention contains a polar group urea group, which can be adsorbed on the metal surface; at the same time, it contains a long carbon chain hydrophobic hydrocarbon group to form a protective film on the metal surface, preventing moisture from corroding the metal surface, thereby achieving a highly efficient rust prevention effect. DETAILED DESCRIPTION

[0021] The present invention will be further explained below in conjunction with specific implementation modes. It should be understood that the following specific implementation modes are only used to illustrate the present invention and are not used to limit the scope of the present invention. Example 1

[0022] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel and a reflux condenser, 60g of methanol and 20.6g of diethylenetriamine were added, the temperature was raised to 45°C with stirring, 52g of dodecyl methacrylate was slowly added dropwise, and the mixture was stirred for 2h after the addition, and then 40g of 2-ureidoethyl methacrylate (i.e., WAMⅩ) was continuously added dropwise, and the mixture was kept warm for reaction for 3h after the addition, the temperature was lowered and the material was discharged, and the methanol was rotary evaporated to obtain a bright yellow liquid, i.e., the aqueous rust inhibitor of the present invention. Example 2

[0023] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel and a reflux condenser, 65g of tetrahydrofuran and 21g of diethylenetriamine were added, the temperature was raised to 45°C with stirring, 52g of dodecyl methacrylate was slowly added dropwise, and the mixture was stirred for 2h after the addition, and then 80g of 2-ureidoethyl methacrylate (i.e., WAMⅩ) was continuously added dropwise, and the mixture was kept warm for reaction for 3h after the addition, the temperature was lowered and the material was discharged, and the tetrahydrofuran was rotary evaporated to obtain a bright yellow liquid, i.e., the aqueous rust inhibitor of the present invention. Example 3

[0024] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel and a reflux condenser, 45g of tetrahydrofuran and 15g of ethylenediamine were added, the temperature was raised to 45°C with stirring, 50g of isooctyl methacrylate was slowly added dropwise, and the mixture was stirred for 2h after the addition, and then 49.5g of 2-ureidoethyl methacrylate (i.e., WAMⅩ) was continuously added dropwise, and the mixture was kept warm for 3h after the addition, the temperature was lowered and the material was discharged, and the tetrahydrofuran was rotary evaporated to obtain a bright yellow liquid, i.e., the aqueous rust inhibitor of the present invention. Example 4

[0025] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel and a reflux condenser, 45g of cyclohexane and 15g of propylamine were added, the temperature was raised to 45°C with stirring, 46g of n-octyl acrylate was slowly added dropwise, and the mixture was stirred for 2h after the addition, and then 50g of 2-ureidoethyl methacrylate (i.e., WAMⅩ) was continuously added dropwise, and the mixture was kept warm for reaction for 3h after the addition, the temperature was lowered and the material was discharged, and the cyclohexane was rotary evaporated to obtain a bright yellow liquid, i.e., the aqueous rust inhibitor of the present invention. Example 5

[0026] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel and a reflux condenser, 60g of tetrahydrofuran and 22.4g of 1,5-pentanediamine were added, the temperature was raised to 45°C with stirring, 22.6g of decyl methacrylate was slowly added dropwise, and the mixture was stirred for 2h after the addition, and then 40g of 2-ureidoethyl methacrylate (i.e., WAMⅩ) was continuously added dropwise, and the mixture was kept warm for reaction for 3h after the addition, the temperature was lowered and the material was discharged, and the tetrahydrofuran was rotary evaporated to obtain a bright yellow liquid, i.e., the aqueous rust inhibitor of the present invention. Example 6

[0027] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel and a reflux condenser, 60g of N,N-dimethylformamide and 23.2g of hexamethylenediamine were added, the temperature was raised to 45°C with stirring, 48g of undecyl methacrylate was slowly added dropwise, and the mixture was stirred for 2h after the addition, and then 40g of 2-ureidoethyl methacrylate (i.e., WAMⅩ) was continuously added dropwise, and the mixture was kept warm for reaction for 3h after the addition, the temperature was lowered and the material was discharged, and N,N-dimethylformamide was rotary evaporated to obtain a bright yellow liquid, i.e., the water-based rust inhibitor of the present invention. Example 7

[0028] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel and a reflux condenser, 67.5g of N,N-dimethylformamide and 22.5g of 3-propanolamine were added, the temperature was raised to 45°C with stirring, 56g of n-octyl acrylate was slowly added dropwise, and the mixture was stirred for 2h after the addition, and then 60g of 2-ureidoethyl methacrylate (i.e., WAMⅩ) was continuously added dropwise, and the mixture was kept warm for reaction for 3h after the addition, the temperature was lowered and the material was discharged, and N,N-dimethylformamide was rotary evaporated to obtain a bright yellow liquid, i.e., the water-based rust inhibitor of the present invention. Example 8

[0029] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel and a reflux condenser, 70g of ethanol and 30g of triethylenetetramine were added, the temperature was raised to 45°C with stirring, 40g of n-octyl methacrylate was slowly added dropwise, and the mixture was stirred for 2h after the addition, and then 80g of 2-ureidoethyl methacrylate (i.e., WAMⅩ) was continuously added dropwise, and the mixture was kept warm for reaction for 3h after the addition, the temperature was lowered and the material was discharged, and the ethanol was rotary evaporated to obtain a bright yellow liquid, i.e., the aqueous rust inhibitor of the present invention. Comparative Example 1

[0030] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel, and a reflux condenser, add 60g of methanol and 20.6g of diethylenetriamine, stir and heat to 45°C, slowly drop 52g of dodecyl methacrylate, keep warm for 2h, and rotary evaporate the methanol to obtain a yellow liquid. Comparative Example 2

[0031] In a 250ml four-necked flask equipped with a stirrer, a thermometer, a titration funnel and a reflux condenser, add 65g of tetrahydrofuran and 13g of diethylenetriamine, stir and heat to 45°C, slowly drop 50g of 2-ureidoethyl methacrylate (i.e. WAMⅩ), keep warm for 3h after the dropwise addition, cool and discharge, and rotary evaporate the tetrahydrofuran to obtain a yellow liquid.

[0032] Application Testing The rust prevention experiment refers to JB / T9189-2016, and 2±0.1g cast iron chips weighed by the balance are evenly dispersed on a filter paper with a diameter of 40㎜ and placed in a culture dish. The rust inhibitor of the present invention is diluted with water to 0.5%-2% (mass fraction) and stirred evenly, and 2ml is evenly dropped on the surface of the cast iron chips with a 2ml dropper to wet the surface of the cast iron chips, and placed at room temperature for 120min (no more than 130min), then the iron chips are removed, and the filter paper is rinsed under water (the water speed should not be too fast), and then rinsed in acetone for about 5s, and the number and area of ​​rust spots on the filter paper are visually compared after drying at room temperature. The experimental results are shown in Table 1.

[0033] Table 1 Antirust performance of rust inhibitors with different mass fractions 0.5% 1% 1.5% 2% Comparative Example 1 Level 4 Level 4 Level 3 Level 3 Comparative Example 2 Level 4 Level 4 Level 3 Level 3 Example 1 Level 0-1 Level 0 Level 0 Level 0 Example 2 Level 0-1 Level 0 Level 0 Level 0 Example 3 Level 0-1 Level 0 Level 0 Level 0 Example 4 Level 0-1 Level 0 Level 0 Level 0 Example 5 Level 0-1 Level 0 Level 0 Level 0 Example 6 Level 0-1 Level 0 Level 0 Level 0 Example 7 Level 1 Level 0 Level 0 Level 0 Example 8 Level 0 Level 0 Level 0 Level 0 The anti-rust grade is divided into 5 grades from 0 to 4, among which grade 0 means no rust; grade 1 means slight rust, with a maximum of three rust spots, and the maximum rust spot does not exceed 1mm; grade 2 means light rust; grade 3 means moderate rust; and grade 4 means severe rust. If one of the two filter papers shows grade 0 and the other shows grade 1, the anti-rust performance is grade 0-1. The data in the table show that compared with the comparative example, the additive containing Example 1 is as effective as the additives of Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, and Example 8, that is, the low concentration of the rust inhibitor of the present invention has an excellent anti-rust effect.

[0034] It should be noted that the above content only illustrates the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing an environmentally friendly water-based high-efficiency rust inhibitor, characterized in that: The following steps are involved: Add amine monomers to the solvent, stir and heat to 25-90°C, first drop acrylic monomers, then drop urea monomers, keep warm for 3-5 hours, cool, and rotary evaporate to obtain a water-based high-efficiency rust inhibitor.

2. The method for preparing an environmentally friendly water-based high-efficiency rust inhibitor according to claim 1, characterized in that: The molar ratio of the amine monomer, acrylic acid monomer and urea monomer is 1:1-2:1-3; the mass ratio of the solvent to the amine monomer is 2-3:

1.

3. The method for preparing an environmentally friendly water-based high-efficiency rust inhibitor according to claim 1, characterized in that: The amine monomer is one or more of ethylamine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, propylamine, n-butylamine, isobutylamine, 1,4-butylenediamine, 1,5-pentanediamine, hexylamine, hexylenediamine, n-heptylamine, n-octylamine, 1-nonylamine, n-decylamine, diethylenetriamine, triethylenetetramine, pentaethylenetetramine, monoethanolamine, 3-propanolamine, monoisopropanolamine, and aniline.

4. The method for preparing an environmentally friendly water-based high-efficiency rust inhibitor according to claim 1, characterized in that: The acrylic acid ester monomer is one or more of n-octyl acrylate, decyl acrylate, tetradecyl acrylate, isooctyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, and tridecyl 2-methyl-2-acrylate.

5. The method for preparing an environmentally friendly water-based high-efficiency rust inhibitor according to claim 1, characterized in that: The structure of the urea monomer is shown below: （1）； or （2）； Wherein, n is an integer from 1 to 5; X is O, NH or NR, wherein R is methyl or ethyl; Y is H or CH3.

6. The method for preparing an environmentally friendly water-based high-efficiency rust inhibitor according to claim 5, characterized in that: The urea-based monomer is one or more of ethyl imidazolone (meth) acrylate, ethyl imidazolone (meth) acrylamide, 1-[2-[[2-hydroxy-3-(2-allyloxy)propyl]amino]ethyl-2-imidazolone, 2-(2-oxo-1-imidazolidinyl)ethyl methacrylate, and N-[2-(2-oxo-1-imidazolidinyl)ethyl]methacrylamide.

7. The method for preparing an environmentally friendly water-based high-efficiency rust inhibitor according to claim 1, characterized in that: The solvent is one or more of methanol, ethanol, cyclohexane, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, and N-methylpyridine.

8. An environmentally friendly water-based high-efficiency rust inhibitor prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the environmentally friendly water-based high-efficiency rust inhibitor as claimed in claim 8 in water-based cutting fluid.

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