Corrosion inhibitor and preparation method thereof

Abstract

The invention provides a corrosion inhibitor and a preparation method thereof, the corrosion inhibitor comprises the following components: halide, imidazoline compound, methyl butynol and water, the mass ratio of halide to imidazoline compound is 0.25: 1-10: 1, and the mass ratio of halide to methyl butynol is 0.15: 1-5: 1. The corrosion inhibitor provided by the invention is convenient to compound, does not contain phosphorus element, and plays a good role in protecting the aquatic environment.

Description

Technical Field

[0001] The invention relates to a corrosion inhibitor and a preparation method thereof. Background Art

[0002] With the development of petrochemical industry, higher requirements are put forward for the durability of its working equipment (especially the working section of metal materials). However, metal materials are often damaged by corrosive media or micro-battery reactions. The most suitable way to solve such corrosion is to add corrosion inhibitors.

[0003] Since the first appearance of corrosion inhibitors more than 100 years ago, they have experienced a gradual development from inorganic to organic, from single to compound, from high toxicity to low toxicity, and from phosphine-containing to low-phosphorus. Currently, commonly used corrosion inhibitors still have problems such as phosphine-containing, high cost, and narrow application range. Summary of the invention

[0004] In order to solve the above-mentioned technical problems, the present invention provides a corrosion inhibitor and a method for preparing the corrosion inhibitor.

[0005] The corrosion inhibitor disclosed in the present invention comprises the following components: a halide, an imidazoline compound, methylbutynol and water, wherein the mass ratio of the halide to the imidazoline compound is 0.25:1-10:1, and the mass ratio of the halide to the methylbutynol is 0.15:1-5:1.

[0006] As an embodiment, the mass ratio of the halide to the imidazoline compound is 0.3:1-6:1, or 0.5:1-3:1. The mass ratio of the halide to methylbutynol is 0.2:1-3:1, or 0.25:1-1.5:1, or 0.3:1-1.5:1.

[0007] In the corrosion inhibitor of the present invention, the halide mainly provides halogen ions. Due to its high electronegativity, it can be adsorbed on the metal surface covered with cations, making it electronegative, and then adsorb other active components of the corrosion inhibitor in the water (imidazoline compound or methylbutynol) to form a bridging effect, thereby achieving a synergistic effect. In the present invention, the halide is preferably an inorganic salt containing bromine and iodine; chloride may enter the gap between metal atoms due to its small size of chloride ions, causing pitting corrosion and affecting the corrosion inhibition effect.

[0008] The halide is an inorganic salt containing bromine or iodine. As an embodiment, the halide is selected from at least one of potassium bromide, potassium iodide, sodium bromide and sodium iodide.

[0009] As an embodiment, the imidazoline compound is selected from at least one of cationic imidazoline, nonionic imidazoline and water-soluble imidazoline.

[0010] As one of the main components of corrosion inhibitors, imidazoline compounds mainly rely on the synergistic effect of other anions (such as bromide ions and iodide ions), or rely on their own lone pair of electrons to combine with the empty orbitals on the metal surface, or form large π bonds and other methods to disperse on the metal surface, thereby changing its potential and reducing the possibility of corrosion caused by micro-battery reactions.

[0011] As an embodiment, the imidazoline compound is a nonionic imidazoline, and its structure is shown in the following formula:

[0012]

[0013] Methylbutynol is also an organic corrosion inhibitor with good adsorption properties. When combined with imidazoline compounds, the corrosion inhibition performance is further improved due to the synergistic effect of the two.

[0014] As an embodiment, the mass ratio of halide to water is 0.075:1-0.5:1; as another embodiment, the mass ratio of halide to water is 0.1:1-0.3:1.

[0015] As an embodiment, the mass ratio of the imidazoline compound to water is 0.05:1-0.3:1; as another embodiment, the mass ratio of the imidazoline compound to water is 0.1:1-0.2:1.

[0016] As an embodiment, the mass ratio of methylbutynol to water is 0.1:1-0.5:1; as another embodiment, the mass ratio of methylbutynol to water is 0.2:1-0.3:1.

[0017] Another aspect of the present disclosure provides a method for preparing a corrosion inhibitor, comprising the following steps:

[0018] 1) adding a halide to water and mixing to obtain a solution A;

[0019] 2) adding the imidazoline compound and methylbutynol to solution A and mixing to obtain a corrosion inhibitor;

[0020] The mass ratio of the halide to the imidazoline compound is 0.25:1-10:1, and the mass ratio of the halide to methylbutynol is 0.15:1-5:1.

[0021] As one embodiment, the temperature during the mixing process in step 1) is ≤40°C; as another embodiment, the temperature during the mixing process is 20-30°C.

[0022] As an embodiment, the mixing process in step 1) adopts stirring mixing, wherein the stirring rate is 20-80rpm; as another embodiment, the stirring rate in the mixing process is 30-60rpm.

[0023] As an embodiment, the mixing process in step 1) adopts stirring mixing, wherein the stirring time is ≤30min; as another embodiment, the stirring time in the mixing process is 10-20min.

[0024] As one embodiment, the temperature during the mixing process in step 2) is ≤40°C; as another embodiment, the temperature during the mixing process in step 2) is 20-30°C.

[0025] As an embodiment, the mixing process in step 2) is carried out by stirring mixing, wherein the stirring rate is 20-80 rpm; as another embodiment, the stirring rate in the mixing process in step 2) is 30-60 rpm.

[0026] As an embodiment, the mixing process in step 2) is carried out by stirring, wherein the stirring time is ≤30 min; as another embodiment, the stirring time in the mixing process in step 2) is 10-20 min.

[0027] The corrosion inhibitor provided by the present disclosure is easy to compound, does not contain phosphorus, and has a good protective effect on the aquatic environment. The corrosion inhibitor has good corrosion inhibition effect, no irritating odor, low toxicity, no strong corrosiveness, good storage stability, can adapt to storage and transportation at extremely low temperatures, and is suitable for corrosion inhibition of industrial equipment made of copper and stainless steel during the cleaning process to prevent the equipment itself from being damaged by acid / alkaline cleaning solutions. DETAILED DESCRIPTION

[0028] In order to make the technical solution of the present invention more obvious and easy to understand, a detailed description is given below in conjunction with specific embodiments.

[0029] In the following examples, the corrosion inhibition experiment was carried out according to the standard GB / T18175-2014 "Determination of corrosion inhibition performance of water treatment agents - Rotating hanging plate method", with the test environment temperature at 45°C and the test time for 48h.

[0030] The corrosion rate calculation formula is K = (M0-M1) / st,

[0031] Where:

[0032] K = corrosion rate, g / (m 2 h),

[0033] M0 = weight before coupon test, g,

[0034] M1 = mass after coupon test, g,

[0035] S = hanging piece surface area, m 2 ,

[0036] T = test time, h,

[0037] The corrosion inhibition rate calculation formula is η=(K0-K1) / K0,

[0038] Where:

[0039] η=corrosion inhibition rate, %

[0040] K0 = metal corrosion rate of blank test group, g / (m 2 h),

[0041] K1 = metal corrosion rate of the tested group, g / (m 2 h),

[0042] Example 1: Take 0.75g potassium bromide, stir and dissolve it in 10g water at 40°C at 80rpm for 30min, then add 3g methylbutynol and 1g water-soluble imidazoline (purchased from Dongying Keling Chemical Co., Ltd.), stir and dissolve for 30min under the same operating environment. Then the obtained solution is subjected to corrosion inhibition test experiment. The experimental water body is an aqueous solution with 2wt% homemade 751 cleaning solution added, the hanging piece material is H62 brass, the agent concentration is 500ppmm, and the final corrosion rate is 0.03g / (m 2 h), the corrosion inhibition rate is 90%.

[0043] Example 2: Take 5g of potassium iodide, stir and dissolve it in 10g of water at 25°C at 20rpm for 20min, then add 1g of methyl butynol and 0.5g of cationic imidazoline (purchased from Dongying Keling Chemical Co., Ltd.), stir and dissolve for 20min under the same operating environment. Then the obtained solution is subjected to corrosion inhibition test experiment. The experimental water body is an aqueous solution with 2wt% of homemade 751 cleaning solution added, the hanging piece material is H62 brass, the agent concentration is 500ppmm, and the final corrosion rate is 0.06g / (m 2 h), the corrosion inhibition rate is 67%.

[0044] Example 3: Take 1.5g potassium iodide, stir and dissolve it in 10g water at 30°C at 50rpm for 15min, then add 1.5g methylbutynol and 2g non-ionic imidazoline (purchased from Dongying Keling Chemical Co., Ltd.), stir and dissolve for 20min under the same operating environment. Then the obtained solution is subjected to corrosion inhibition test experiment. The experimental water body is an aqueous solution with 2wt% homemade 751 cleaning solution added, the hanging piece material is H62 brass, the agent concentration is 500ppmm, and the final corrosion rate is 0.02g / (m 2 h), the corrosion inhibition rate is 92%.

[0045] Example 4: Take 1g of potassium bromide, stir and dissolve it in 10g of water at 20°C at 60rpm for 10min, then add 5g of methyl butynol and 3g of non-ionic imidazoline (purchased from Dongying Keling Chemical Co., Ltd.), stir and dissolve for 10min under the same operating environment. Then the obtained solution is subjected to corrosion inhibition test experiment. The experimental water body is an aqueous solution added with 2% of 711 cleaning solution produced by our company, the hanging piece material is H62 brass, the reagent concentration is 500ppmm, and the final corrosion rate is 0.08g / (m 2 h), the corrosion inhibition rate is 67%.

[0046] Example 5: Take 3g of potassium bromide, stir and dissolve it in 10g of water at 40°C at 40rpm for 15min, then add 2g of methyl butynol and 1.5g of cationic imidazoline (purchased from Dongying Keling Chemical Co., Ltd.), stir and dissolve for 15min under the same operating environment. Then the obtained solution is subjected to corrosion inhibition test experiment. The experimental water body is an aqueous solution with 2wt% of homemade 751 cleaning solution added, the hanging piece material is 304 stainless steel, the reagent concentration is 500ppmm, and the final corrosion rate is 0.002g / (m 2 h), the corrosion inhibition rate is 60%.

Claims

1. A corrosion inhibitor, characterized in that: The invention comprises the following components: a halide, an imidazoline compound, methylbutynol and water, wherein the mass ratio of the halide to the imidazoline compound is 0.25:1-10:1, and the mass ratio of the halide to the methylbutynol is 0.15:1-5:

1.

2. The corrosion inhibitor according to claim 1, characterized in that The mass ratio of the halide to the imidazoline compound is 0.5:1-3:1, and the mass ratio of the halide to methylbutynol is 0.25:1-1.5:

1.

3. The corrosion inhibitor according to claim 1, characterized in that The halide is selected from at least one of potassium bromide, potassium iodide, sodium bromide and sodium iodide.

4. The corrosion inhibitor according to claim 1, characterized in that The imidazoline compound is selected from at least one of cationic imidazoline, nonionic imidazoline and water-soluble imidazoline.

5. The corrosion inhibitor according to claim 4, characterized in that The imidazoline compound is nonionic imidazoline.

6. The corrosion inhibitor according to claim 1, characterized in that The mass ratio of the halide to water is 0.075:1-0.5:1, the mass ratio of the imidazoline compound to water is 0.05:1-0.3:1, and the mass ratio of methylbutynol to water is 0.1:1-0.5:

1.

7. A method for preparing a corrosion inhibitor, comprising the following steps: 1) adding a halide to water and mixing to obtain a solution A; 2) adding the imidazoline compound and methylbutynol to solution A and mixing to obtain a corrosion inhibitor; in, The mass ratio of the halide to the imidazoline compound is 0.25:1-10:1, and the mass ratio of the halide to the methylbutynol is 0.15:1-5:

1.

8. The method for preparing the corrosion inhibitor according to claim 7, characterized in that: In step 1), the temperature during the mixing process is ≤40° C. and the mixing time is ≤30 min.

9. The method for preparing the corrosion inhibitor according to claim 7, characterized in that: In step 2), the temperature during the mixing process is ≤40° C. and the mixing time is ≤30 min.

10. The method for preparing the corrosion inhibitor according to claim 7, characterized in that: The halide is selected from at least one of potassium bromide, potassium iodide, sodium bromide and sodium iodide, and the imidazoline compound is selected from at least one of cationic imidazoline, nonionic imidazoline and water-soluble imidazoline.

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