Preparation process of neutral amino acid-based scale and corrosion inhibitor

Abstract

The present invention relates to the technical field of scale and corrosion inhibitors, and discloses a preparation process of a neutral amino acid-based scale and corrosion inhibitor. The present invention reacts 3,5-dihydroxybenzaldehyde, taurine, epichlorohydrin, and N,N,N',N'-tetramethylethylenediamine to obtain a scale and corrosion inhibitor. The sulfonate and hydroxyl groups contained in the scale and corrosion inhibitor form stable chelates with barium ions and strontium ions, which can prevent the barium ions and strontium ions from combining with anions such as sulfate to form insoluble precipitates such as barium sulfate and strontium sulfate, thereby achieving excellent scale inhibition performance. The scale and corrosion inhibitor contains multiple active coordination centers of quaternary ammonium salt cations, sulfonate, and hydroxyl groups, which interact with the surface of a steel sheet to form a tight and firm protective film on the surface, preventing corrosive media such as hydrochloric acid from contacting the steel sheet, achieving excellent anti-corrosion and corrosion inhibition performance at high temperatures, and has good practical applications in oil field water injection and oil production.

Description

Technical Field

[0001] The invention relates to the technical field of scale and corrosion inhibitors, and in particular to a preparation process of a neutral amino acid-based scale and corrosion inhibitor. Background Art

[0002] Due to the high salinity of produced water in some areas of the oilfield, incompatibility between the produced fluid and the injected water can lead to severe scaling in the wellbore pumps and near-wellbore reservoirs. This can lead to the formation of large amounts of inorganic scale such as barium sulfate, strontium sulfate, and calcium carbonate, severely impacting normal production. Furthermore, the presence of high levels of corrosive gases such as carbon dioxide and hydrogen chloride dissolved in produced water can lead to a continuous deterioration in injection water quality, causing severe corrosion to the pipes and equipment in the injection system, posing a significant safety hazard. The development of new scale and corrosion inhibitors is crucial. Chinese patent CN111704250B discloses a neutral corrosion and scale inhibitor for oil fields and a preparation method thereof. The neutral corrosion and scale inhibitor obtained by compounding chloroacetic acid, sodium hydroxide solution, ethylenediamine, phosphorous acid, aminotrimethoxyphosphoric acid, and bis(carboxyethyl) hypophosphorous acid has good corrosion and scale inhibition properties. However, the corrosion and scale inhibitor does not show a good scale inhibition effect on strontium and barium scale. In addition, the corrosion and scale inhibitor contains a large amount of phosphorus-containing substances, which can easily cause environmental problems such as eutrophication and red tides when entering the natural water environment. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the present invention provides a preparation process of a neutral amino acid-based scale and corrosion inhibitor, which solves the problem that the existing scale and corrosion inhibitor has poor scale inhibition performance on barium and strontium, and at the same time has good high-temperature corrosion inhibition and anti-corrosion performance.

[0004] Technical solution: Preparation process of a neutral amino acid-based scale and corrosion inhibitor:

[0005] (1) Methanol, 3,5-dihydroxybenzaldehyde, and taurine are added to a reaction vessel, and a methanol solution containing potassium hydroxide is added dropwise. After the reaction, rotary evaporation is performed, and the product is recrystallized in an ethanol aqueous solution to obtain a Schiff base of 3,5-dihydroxybenzaldehyde-taurate potassium.

[0006] (2) Toluene, epichlorohydrin, 3,5-dihydroxybenzaldehyde taurate potassium Schiff base, and benzyltriethylammonium chloride (TEBAC) were added to the reaction vessel. After the reaction, the mixture was rotary evaporated, washed with petroleum ether, and the product was recrystallized in ethanol aqueous solution to obtain 3,5-bis(3-chloro-2-hydroxypropoxy)benzaldehyde taurate potassium Schiff base. The preparation reaction formula is:

[0007] .

[0008] (3) Add the solvent, 3,5-bis(3-chloro-2-hydroxypropyloxy)benzaldehyde taurine potassium Schiff base and N,N,N',N'-tetramethylethylenediamine in a molar ratio of 1:(0.9-1.1) to the reaction vessel. After the reaction, cool the solution and pour it into ethanol. After filtering, wash it with ethanol and dry it to obtain a neutral amino acid-based scale and corrosion inhibitor. The preparation reaction formula is:

[0009] .

[0010] Preferably, the reaction in (1) is stirred at 30-50°C for 1-2 hours.

[0011] Preferably, the molar ratio of 3,5-dihydroxybenzaldehyde, taurine and potassium hydroxide in (1) is 1:(1-1.2):(1-1.2).

[0012] Preferably, the reaction temperature in (2) is 90-100°C and the reaction time is 8-12h.

[0013] Preferably, the molar ratio of epichlorohydrin, 3,5-dihydroxybenzaldehyde potassium taurate Schiff base, and benzyltriethylammonium chloride in (2) is (10-14):1:(0.11-0.15).

[0014] Preferably, the solvent in (3) is N,N-dimethylformamide or N,N-dimethylacetamide.

[0015] Preferably, the reaction in (3) is stirred at 90-120°C for 24-48 hours.

[0016] The beneficial technical effects of the present invention are as follows: the scale and corrosion inhibitor prepared by the present invention contains a zwitterionic structure of sulfonate and quaternary ammonium salt, presents electrical neutrality, and has little corrosion and damage to the steel pipeline substrate in the oil field water injection system. In addition, the scale and corrosion inhibitor contains a large number of hydroxyl, sulfonate, and quaternary ammonium salt hydrophilic groups and has good solubility in water. At the same time, the sulfonate and hydroxyl contained in the scale and corrosion inhibitor have strong chelating properties and form stable chelates with barium ions and strontium ions, which can prevent the barium ions and strontium ions from combining with anions such as sulfate to form insoluble precipitates such as barium sulfate and strontium sulfate, thereby achieving good scale and anti-scaling performance.

[0017] The scale and corrosion inhibitor of the present invention is a polymer containing benzene rings with excellent heat resistance. It also contains multiple active coordination centers, including quaternary ammonium salt cations, sulfonates, and hydroxyl groups. It interacts strongly with the surface of the steel sheet, forming a tight and strong protective film on the steel sheet. This effectively blocks contact with corrosive media such as hydrochloric acid and provides excellent corrosion protection and inhibition at high temperatures. The scale and corrosion inhibitor of the present invention is phosphorus-free, environmentally friendly, and pollution-free, and has good practical application in oilfield water injection and oil recovery. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0019] Example 1

[0020] (1) Add 60 mL of methanol, 20 mmol of 3,5-dihydroxybenzaldehyde, and 20 mmol of taurine to a reaction vessel equipped with a reflux tube, and dropwise add 60 mL of a methanol solution containing 20 mmol of potassium hydroxide. Stir the mixture at 50°C for 1 h, remove the methanol by rotary evaporation, and recrystallize the product from a 50% by volume ethanol aqueous solution to obtain a Schiff base of 3,5-dihydroxybenzaldehyde potassium taurate.

[0021] (2) To a reaction vessel equipped with a condenser reflux tube, 30 mL of toluene, 140 mmol of epichlorohydrin, 10 mmol of 3,5-dihydroxybenzaldehyde taurate potassium Schiff base, and 0.1 mmol of benzyltriethylammonium chloride were added, and the mixture was stirred at 90 °C for 12 h. The toluene and epichlorohydrin were removed by rotary evaporation, and the mixture was washed with petroleum ether. The product was recrystallized in a 70% by volume ethanol aqueous solution to obtain 3,5-bis(3-chloro-2-hydroxypropoxy)benzaldehyde taurate potassium Schiff base.

[0022] (3) Add 200 mL of N,N-dimethylformamide, 20 mmol of 3,5-bis(3-chloro-2-hydroxypropyloxy)benzaldehyde taurine potassium Schiff base, and 20 mmol of N,N,N',N'-tetramethylethylenediamine to the reaction vessel, stir and react at 110°C for 30 h, and after cooling, pour the solution into ethanol, filter, wash with ethanol, and dry to obtain a neutral amino acid-based scale and corrosion inhibitor.

[0023] Example 2

[0024] (1) Add 80 mL of methanol, 20 mmol of 3,5-dihydroxybenzaldehyde, and 24 mmol of taurine to a reaction vessel, and dropwise add 70 mL of a methanol solution containing 24 mmol of potassium hydroxide. Stir and react at 30°C for 2 h. Remove the methanol by rotary evaporation. The product is recrystallized in a 50% by volume ethanol aqueous solution to obtain a Schiff base of 3,5-dihydroxybenzaldehyde potassium taurate.

[0025] (2) Add 20 mL of toluene, 100 mmol of epichlorohydrin, 10 mmol of 3,5-dihydroxybenzaldehyde taurate potassium Schiff base, and 0.15 mmol of benzyltriethylammonium chloride to a reaction vessel equipped with a condenser reflux tube, stir at 100 °C for 8 h, remove toluene and epichlorohydrin by rotary evaporation, wash with petroleum ether, and recrystallize the product in a 70% by volume ethanol aqueous solution to obtain 3,5-bis(3-chloro-2-hydroxypropoxy)benzaldehyde taurate potassium Schiff base.

[0026] (3) Add 200 mL of N,N-dimethylacetamide, 20 mmol of 3,5-bis(3-chloro-2-hydroxypropyloxy)benzaldehyde taurine potassium Schiff base, and 22 mmol of N,N,N',N'-tetramethylethylenediamine to the reaction vessel, stir and react at 90°C for 48 h, and pour the solution into ethanol after cooling. After filtration, wash with ethanol, and dry to obtain a neutral amino acid-based scale and corrosion inhibitor.

[0027] Example 3

[0028] (1) Add 200 mL of N,N-dimethylformamide, 20 mmol of 3,5-bis(3-chloro-2-hydroxypropoxy)benzaldehyde potassium taurate Schiff base (prepared in Example 1), and 18 mmol of N,N,N',N'-tetramethylethylenediamine to a reaction vessel, stir and react at 120°C for 24 h, and after cooling, pour the solution into ethanol, filter, wash with ethanol, and dry to obtain a neutral amino acid-based scale and corrosion inhibitor.

[0029] In Comparative Example 1, 3,5-bis(3-chloro-2-hydroxypropoxy)benzaldehyde potassium taurate Schiff base was used as a scale and corrosion inhibitor (prepared in Example 1).

[0030] Comparative Example 2

[0031] (1) Add 200 mL of N,N-dimethylformamide and 20 mmol of p-dibenzyl chloride (structural formula: ), 20mmol N,N,N',N'-tetramethylethylenediamine, stirred and reacted at 110°C for 30h, poured the solution into ethanol after cooling, filtered, washed with ethanol, and dried to obtain a scale and corrosion inhibitor.

[0032] Comparative Example 3

[0033] (1) Add 30 mL of toluene, 140 mmol of epichlorohydrin, 10 mmol of hydroquinone, and 0.1 mmol of benzyltriethylammonium chloride to a reaction vessel equipped with a condenser reflux tube, stir at 90°C for 12 h, remove toluene and epichlorohydrin by rotary evaporation, and recrystallize the product in ethanol to obtain 1,4-bis(3-chloro-2-hydroxypropoxy)benzene, the structural formula of which is .

[0034] (2) Add 200 mL of N,N-dimethylformamide, 20 mmol of 1,4-bis(3-chloro-2-hydroxypropoxy)benzene, and 20 mmol of N,N,N',N'-tetramethylethylenediamine to the reaction vessel, stir and react at 110°C for 30 h, and after cooling, pour the solution into ethanol, filter, wash with ethanol, and dry to obtain a scale and corrosion inhibitor.

[0035] The scale inhibition rate of barium sulfate and strontium sulfate was tested using the method specified in SY / T 5673-2020. The dosage of the scale inhibitor was 10-25 mg / L. The test results are shown in Table 1-2.

[0036] Table 1 Anti-scaling rate test of barium sulfate

[0037]

[0038] Table 2 Strontium sulfate anti-scaling rate test

[0039]

[0040] After testing, the scale inhibition and corrosion inhibitors of Examples 1-3 have the highest scale inhibition rates for barium sulfate and strontium sulfate, reaching 98.5% and 96.0% respectively. This is mainly because the scale inhibition and corrosion inhibitors contain sulfonate, hydroxyl and quaternary ammonium salt hydrophilic groups, and have good solubility in water. At the same time, the sulfonate and hydroxyl contained in them have strong chelating properties, forming stable chelates with barium ions and strontium ions, which can prevent barium ions and strontium ions from combining with anions such as sulfate to form insoluble precipitates such as barium sulfate and strontium sulfate, thereby achieving good scale inhibition and anti-scaling performance.

[0041] Comparative Example 1 uses potassium 3,5-bis(3-chloro-2-hydroxypropyloxy)benzaldehyde taurate as a scale and corrosion inhibitor. This Schiff base also contains sulfonates and hydroxyl groups, which have strong chelating properties and form stable chelates with barium and strontium ions, providing excellent scale and anti-scaling performance. However, its barium sulfate and strontium sulfate scale inhibition rates are lower than those of Example 1. This is primarily because potassium 3,5-bis(3-chloro-2-hydroxypropyloxy)benzaldehyde taurate lacks a quaternary ammonium cationic hydrophilic group and has poor water solubility, which affects its scale inhibition performance. Comparative Example 2 uses p-dibenzyl chloride and N,N,N',N'-tetramethylethylenediamine as raw materials. The scale and corrosion inhibitor prepared lacks sulfonates and hydroxyl groups, lacks chelating properties, and struggles to form stable chelates with barium and strontium ions. Consequently, its scale inhibition rate is very low and its scale and anti-scaling performance is very poor. Comparative Example 3 uses 1,4-bis(3-chloro-2-hydroxypropoxy)benzene and N,N,N',N'-tetramethylethylenediamine as reactants. The resulting scale and corrosion inhibitor does not contain a sulfonate group, has poor chelating performance, a low scale prevention rate, and poor scale inhibition performance.

[0042] The corrosion inhibition performance of the scale and corrosion inhibitor was tested according to the method specified in the SYT / 5273-2014 standard. The test specimen was an A3 steel sheet (50 mm × 13 mm × 1.5 mm). The corrosion solution was a 20% by mass hydrochloric acid solution. The scale and corrosion inhibitor dosage in the corrosion solution was 5-20 mg / L. The corrosion solution was heated to 90°C, condensed, and refluxed for 24 hours. The corrosion inhibition performance test results are shown in Table 3.

[0043] Table 3: Corrosion inhibition performance test

[0044]

[0045] After testing, compared with comparative examples 1-3, the scale inhibitor and corrosion inhibitor of Examples 1-3 has a high-temperature corrosion inhibition rate of up to 93.7% for A3 steel sheets. This is mainly because the scale inhibitor and corrosion inhibitor is a polymer containing a benzene ring and has excellent heat resistance. It also contains multiple active coordination neutrals such as quaternary ammonium salt cations, sulfonates and hydroxyls, which have a strong coordination interaction with the surface of the steel sheet, forming a tight and firm protective film on the surface of the steel sheet, which can effectively prevent corrosive media such as hydrochloric acid from contacting the steel sheet, and has excellent anti-corrosion and corrosion inhibition properties at high temperatures.

[0046] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A preparation process of a neutral amino acid-based scale and corrosion inhibitor, characterized in that: The preparation process is as follows: a solvent, a Schiff base of 3,5-bis(3-chloro-2-hydroxypropyloxy)benzaldehyde taurate potassium, and N,N,N',N'-tetramethylethylenediamine in a molar ratio of 1:(0.9-1.1) are added to a reaction container, the reaction is completed, the solution is cooled, poured into ethanol, filtered, washed with ethanol, and dried to obtain a neutral amino acid-based scale and corrosion inhibitor; The structural formula of the 3,5-bis(3-chloro-2-hydroxypropoxy)benzaldehyde potassium taurate Schiff base is as follows: 。 2. The preparation process of the neutral amino acid-based scale and corrosion inhibitor according to claim 1, characterized in that: The solvent is N,N-dimethylformamide or N,N-dimethylacetamide.

3. The preparation process of the neutral amino acid-based scale and corrosion inhibitor according to claim 1, characterized in that: The reaction was stirred at 90-120 °C for 24-48 h.

4. The preparation process of the neutral amino acid-based scale and corrosion inhibitor according to claim 1, characterized in that: The preparation process of the 3,5-bis(3-chloro-2-hydroxypropoxy)benzaldehyde potassium taurate Schiff base is as follows: (1) Methanol, 3,5-dihydroxybenzaldehyde, and taurine are added to a reaction vessel, and a methanol solution containing potassium hydroxide is added dropwise. After the reaction, rotary evaporation is performed, and the product is recrystallized to obtain a Schiff base of 3,5-dihydroxybenzaldehyde potassium taurine; (2) Toluene, epichlorohydrin, 3,5-dihydroxybenzaldehyde taurate potassium Schiff base, and benzyltriethylammonium chloride are added to a reaction vessel. After the reaction, the mixture is rotary evaporated, washed, and the product is recrystallized to obtain 3,5-bis(3-chloro-2-hydroxypropoxy)benzaldehyde taurate potassium Schiff base.

5. The preparation process of the neutral amino acid-based scale and corrosion inhibitor according to claim 4, characterized in that: The reaction in (1) is stirred at 30-50°C for 1-2 hours.

6. The preparation process of the neutral amino acid-based scale and corrosion inhibitor according to claim 4, characterized in that: The molar ratio of 3,5-dihydroxybenzaldehyde, taurine and potassium hydroxide in (1) is 1:(1-1.2):(1-1.2).

7. The preparation process of the neutral amino acid-based scale and corrosion inhibitor according to claim 4, characterized in that: The reaction temperature in (2) is 90-100°C and the reaction time is 8-12h.

8. The preparation process of the neutral amino acid-based scale and corrosion inhibitor according to claim 4, characterized in that: The molar ratio of epichlorohydrin, 3,5-dihydroxybenzaldehyde potassium taurate Schiff base and benzyltriethylammonium chloride in (2) is (10-14):1:(0.11-0.15).

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