Preparation method and application of alcohol amine pour point depressing corrosion inhibitor

Abstract

The invention discloses a preparation method and application of an alcohol amine pour point depressing corrosion inhibitor. A mixture containing a long molecular chain polymer is generated through a condensation polymerization reaction of hydroxyethyl urea and ethanolamine. The alcohol amine pour point depressing corrosion inhibitor has a good improvement effect on low-temperature fluidity of ethanolamine, can slow down corrosion of ethanolamine to non-ferrous metals copper and aluminum, has good storage stability, is simple, convenient and cheap, can effectively reduce the freezing points of diethanolamine and triethanolamine, improves the convenience of using alcohol amine by a user, and has a wide application prospect. And the alcohol amine pour point depressing corrosion inhibitor can slow down the corrosion of ethanol amine to nonferrous metals copper and aluminum, and is suitable for alcohol amine in the metal processing industry.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry, and particularly relates to a preparation method and application of an alcoholamine pour point depressant and corrosion inhibitor. Background Art

[0002] Ethanolamines include monoethanolamine, diethanolamine and triethanolamine. They are important petrochemical raw materials with a wide range of uses. The annual output of ethanolamines in the world is over one million tons. Ethanolamines are widely used in industry, agriculture and daily chemicals. Among them, monoethanolamine is mainly used in surfactants, emulsifiers, metal cleaners, pesticides and pharmaceutical intermediates; diethanolamine is mainly used in surfactants, metalworking fluids, liquid cleaners and aviation fuel deashing agents; triethanolamine is mainly used in cement enhancers, metalworking fluids, cosmetic ingredients and printing ink additives. The freezing points of monoethanolamine, diethanolamine, and triethanolamine are 10.3-10.5℃, 27-28℃, and 17.9-21℃, respectively, while the average temperature in my country in 2023 is 10.71℃, which is much lower than the freezing points of diethanolamine and triethanolamine. In actual production and use, ethanolamine often freezes, affecting the filling, transportation, and use of ethanolamine. At present, the technologies for improving the low-temperature fluidity of chemical raw materials mainly include physical technology and chemical technology. The physical technology is to heat the drying room or coil to make the temperature of ethanolamine higher than the freezing point, but this technology has the disadvantages of high cost and low efficiency. The most widely used chemical technology is the pour point depressant pour point depressant method. At present, there are few pour point depressants related to ethanolamine. In the metal processing industry, aluminum and copper are widely used in aerospace parts and automotive parts, and ethanolamine corrodes aluminum and copper, which has a negative impact on the quality of the workpiece. In view of the above problems, the present invention provides a preparation method and application of an alcoholamine pour point depressant corrosion inhibitor.

[0003] The core principle of an olamine pour point depressant corrosion inhibitor technology is to use hydroxyethyl urea and olamine as the main reaction substances, add ionic liquid catalysts, adjust the pH, and make hydroxyethyl urea and olamine undergo condensation reaction in a relatively mild environment to obtain long-chain polymers, and then add azole compounds for doping modification to obtain an olamine pour point depressant corrosion inhibitor that can effectively inhibit / slow down the crystallization process of olamine in a low temperature environment and can inhibit corrosion on the contacting non-ferrous metal surface. Summary of the invention

[0004] In order to avoid the shortcomings of the prior art, the present invention provides a preparation method and application of an alcoholamine pour point depressant and corrosion inhibitor.

[0005] In order to solve the technical problem, the present invention adopts the following technical solution:

[0006] Hydroxyethyl urea and alcohol amine are used as raw materials, an ionic liquid catalyst is added, and after a polymerization reaction, an azole compound is added and stirred continuously to obtain an alcohol amine pour point depressant and corrosion inhibitor;

[0007] In the first step, hydroxyethyl urea and alcohol amine are evenly mixed, and the catalyst is slowly dripped in while stirring, and the temperature is slowly raised to 150-165°C, and refluxed for 4 hours to obtain a yellow transparent liquid. The heating is stopped, and in the second step, an azole compound is added and stirring is continued for 2 hours to obtain the product alcohol amine pour point depressant corrosion inhibitor.

[0008] The composition comprises 60-70 parts of hydroxyethyl urea, 23-33 parts of alcohol amine, 1-6 parts of ionic liquid catalyst and 1-3 parts of azole compound.

[0009] Preferably, the hydroxyethyl urea is 2-hydroxyethyl urea; the alcohol amine is one or both of monoethanolamine and monoisopropanolamine; the ionic liquid catalyst is N-methylpyrrolidine toluenesulfonic acid ionic liquid catalyst, and the azole compound is benzotriazole, toluenetriazole, 2-methyl-5-mercapto-1,3,4-thiadiazole, mercaptobenzothiazole or a mixture of more than one.

[0010] Further preferably, the hydroxyethyl urea is 2-hydroxyethyl urea; the alcohol amine is monoethanolamine; the ionic liquid catalyst is N-methylpyrrolidone toluenesulfonic acid ionic liquid, and the azole compound is benzotriazole.

[0011] As a second aspect of the present invention, the present invention further discloses the application of the alcoholamine pour point depressant and corrosion inhibitor obtained by the preparation method.

[0012] Adding the pour point depressant and corrosion inhibitor of the present invention to ethanolamine can not only effectively reduce the freezing point of ethanolamine, but also significantly reduce the corrosion of ethanolamine to non-ferrous metal materials such as aluminum and copper, thereby achieving multifunctionality in one dose.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] The preparation method and application of the alcoholamine pour point depressing corrosion inhibitor obtained by the invention have the pour point depressing function for ethanolamine and can also reduce the corrosion of ethanolamine to non-ferrous metals aluminum and copper. DETAILED DESCRIPTION

[0015] The following is a detailed description of an embodiment of the present invention. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0016] Example 1

[0017] Weigh 105g of 2-hydroxyethyl urea and 34.5g of monoethanolamine into a 250ml flat-bottom flask, mix thoroughly with a magnetic stirrer, then slowly drop 7g of N-methylpyrrolidine toluenesulfonic acid ionic liquid catalyst, drip it all over in about 10 minutes, then slowly heat to 150°C and reflux for 4 hours to obtain a clear solution. Then add 2.9g of benzotriazole and continue stirring for 1 hour. The final product 1 is obtained.

[0018] Example 2

[0019] Weigh 90g of 2-hydroxyethyl urea and 49.5g of monoethanolamine into a 250ml flat-bottom flask, mix thoroughly with a magnetic stirrer, then slowly drop 7g of N-methylpyrrolidine toluenesulfonic acid ionic liquid catalyst, drip it all over in about 10 minutes, then slowly heat to 150°C and reflux for 4 hours to obtain a clear solution. Then add 2.9g of benzotriazole and continue stirring for 1 hour. The final product 2 is obtained.

[0020] Example 3

[0021] Weigh 105g of 2-hydroxyethyl urea and 42.5g of monoisopropanolamine into a 250ml flat-bottom flask, mix thoroughly with a magnetic stirrer, then slowly drop 7.4g of N-methylpyrrolidine toluenesulfonic acid ionic liquid catalyst, drip it all over in about 10 minutes, then slowly heat to 150°C and reflux for 4 hours to obtain a clear solution. Then add 3.1g of benzotriazole and continue stirring for 1 hour. The final product 3 is obtained.

[0022] Example 4

[0023] Weigh 90g of 2-hydroxyethyl urea and 60.9g of monoisopropanolamine into a 250ml flat-bottom flask, mix thoroughly with a magnetic stirrer, then slowly drop 7.4g of N-methylpyrrolidine toluenesulfonic acid ionic liquid catalyst, drip it all over in about 10 minutes, then slowly heat to 150°C and reflux for 4 hours to obtain a clear solution. Then add 3.1g of benzotriazole and continue stirring for 1 hour. The final product 4 is obtained.

[0024] Application Example 1: Diethanolamine Pour Point Depression Test

[0025] Experimental instrument: Petroleum product condensation point tester (manufactured by Wuhan Yanrun Technology Development Co., Ltd.)

[0026] Table 1:

[0027]

[0028] Application Example 2: Triethanolamine Pour Point Depression Test

[0029] Table 2

[0030]

[0031]

[0032] Among them, the diethanolamine and triethanolamine in the application example are from Dow Chemical. From the test data in Table 1, it can be seen that the product 1 in the embodiment has a significant effect of lowering the freezing point of diethanolamine. As the amount of product 1 added gradually increases, the freezing point of the diethanolamine mixture gradually decreases. When it decreases to -4°C, it starts to rise again. When the mass fraction of product 1 is 3% and the mass fraction of diethanolamine is 97%, the freezing point of the diethanolamine mixture is the lowest, which is -4°C.

[0033] It can be seen from the test data in Table 2 that the product 1 in the embodiment has an obvious effect of lowering the freezing point of triethanolamine. As the addition amount of the product 1 gradually increases, the freezing point of the triethanolamine mixture gradually decreases. When it decreases to -6°C, it starts to increase again. When the mass fraction of the product 1 is 5% and the mass fraction of triethanolamine is 95%, the freezing point of the diethanolamine mixture is the lowest, which is -6°C.

[0034] Application Example 3: Diethanolamine Corrosion Inhibition Test

[0035] Aluminum corrosion test:

[0036] Main experimental instruments: constant temperature oven, beaker, stretch film

[0037] Experimental method: dilute the alcohol amine / alcohol amine mixture with tap water to a 1% diluent for later use. Immerse the prepared aluminum alloy sheet in a beaker containing the diluent, seal the beaker with a wrapping film, and move it into an oven with a constant temperature of 55°C ± 2°C. After a continuous test of 8 hours, take out the test piece for observation (the implementation standard is GB / T 6144-2010).

[0038] Result judgment:

[0039] Aluminum alloy: rust-free, shiny as new, Grade A

[0040] Slightly darkened Grade B

[0041] Moderate darkening C

[0042] Severe Darkening D

[0043] Aluminum alloy grades A and B are qualified, while grades C and D are unqualified.

[0044] Copper corrosion test:

[0045] Main experimental instruments: constant temperature oven, beaker, glass cover dish

[0046] Experimental methods:

[0047] Experimental method: dilute the alcoholamine / alcoholamine mixture with tap water to a 1% diluent, set aside, immerse the prepared copper sheet in a beaker containing the diluent, seal the beaker with a glass cover, move it into an oven with a constant temperature of 80℃±2℃, and take out the test piece for observation after 48 hours of continuous testing. Result judgment:

[0048] Copper: Rust-free, shiny as new, Grade A

[0049] Mild discoloration Grade B

[0050] Moderate discoloration Grade C

[0051] Severe discoloration level D

[0052] Copper grades A and B are qualified, while grades C and D are unqualified.

[0053] Table 3:

[0054]

[0055] Table 4

[0056]

[0057] Among them, the diethanolamine and triethanolamine in the application example are from Dow Chemical. From the test data in Table 3, it can be seen that the product 1 in the embodiment has a significant effect on inhibiting the corrosion of copper and aluminum by diethanolamine. When the addition amount of product 1 is 3%, the corrosion result of the diethanolamine mixture on aluminum is qualified; when the addition amount of product 1 is 2%, the corrosion result of the diethanolamine mixture on copper is as shiny as new.

[0058] It can be seen from the test data in Table 4 that product 1 in the embodiment has a significant inhibitory effect on the corrosion of copper and aluminum by triethanolamine. When the addition amount of product 1 is 6%, the corrosion result of the triethanolamine mixture on aluminum is qualified; when the addition amount of product 1 is 3%, the corrosion result of the triethanolamine mixture on copper is as shiny as new.

[0059] It can be seen from the above experimental results that the ethanolamine pour point depressant and corrosion inhibitor provided by the present invention can effectively reduce the pour point of ethanolamine and slow down the corrosion of ethanolamine to aluminum and copper.

Claims

1. A method for preparing an alcoholamine pour point depressant corrosion inhibitor, characterized in that: The steps include: Take hydroxyethyl urea and alcohol amine as raw materials, add ionic liquid catalyst, stir evenly and then heat up, the temperature is controlled at 150-165℃, react for 4 hours to obtain a light yellow transparent liquid, add azole compound in the second step, continue stirring and reacting for 3 hours to obtain the product alcohol amine pour point depressant corrosion inhibitor; The composition comprises 60-70 parts of hydroxyethyl urea, 23-33 parts of alcohol amine, 1-6 parts of ionic liquid catalyst and 1-3 parts of azole compound.

2. The preparation method according to claim 1, characterized in that: The hydroxyethyl urea is 2-hydroxyethyl urea; the alcohol amine is one or two of monoethanolamine and monoisopropanolamine; the ionic liquid catalyst is N-methylpyrrolidine toluenesulfonic acid ionic liquid catalyst; the azole compound is benzotriazole, toluenetriazole, 2-methyl-5-mercapto-1,3,4-thiadiazole, mercaptobenzothiazole or a mixture of more than one.

3. The preparation method according to claim 2, characterized in that: The hydroxyethyl urea is 2-hydroxyethyl urea; the alcohol amine is monoethanolamine; the ionic liquid catalyst is N-methylpyrrolidone toluenesulfonic acid ionic liquid, and the azole compound is benzotriazole.

4. The alcoholamine pour point depressant and corrosion inhibitor obtained according to the preparation method according to any one of claims 1 to 3.

5. Use of the alcoholamine pour point depressant corrosion inhibitor obtained by the preparation method according to any one of claims 1 to 3, characterized in that: Applied to diethanolamine and triethanolamine.

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