Double-condensation schiff base and composition containing double-condensation schiff base

Abstract

The invention provides a double condensed Schiff base and a composition containing the same. Structural formula of double-condensation Schiff base as shown in formula 1) # imgabs0 #

Description

Technical Field

[0001] The invention relates to the field of petroleum exploration, and in particular to a double condensed Schiff base which can be used as a high-temperature acidification corrosion inhibitor. Background Art

[0002] With the increasing development of exploration and development technology, deep-ultra-deep oil and gas development has become an important successor to oil and gas resources. The main problem faced by deep-ultra-deep oil and gas development is that the reservoir temperature and water mineralization are getting higher and higher with the increase of mining depth, resulting in serious wellbore corrosion. The current focus of oil and gas exploration and development is gradually turning to deep and ultra-deep oil and gas reservoirs. Most of these oil and gas reservoirs have low porosity and low permeability, and are also characterized by high temperature (reaching 180°C) and high pressure (bottom hole pressure exceeds 16MPa), and the development conditions of oil and gas wells are extremely harsh.

[0003] As an important means to increase the productivity of a single well, acidizing operations have been widely used in the development of deep and ultra-deep oil and gas reservoirs. The risk of acid corrosion on downhole tubing will be greatly increased. Oilfield acidizing technology has increased oil and gas production while also causing a series of tubing corrosion problems. If the tubing corrosion problem is not effectively controlled, it will not only cause the tubing to stop production due to overhaul, but may even cause the oil and gas well to be scrapped. In recent years, as the mining environment has become increasingly severe and the mining depth has continued to deepen, the acidizing process mainly uses the method of adding corrosion inhibitors to deal with tubing corrosion problems.

[0004] In order to meet the needs of environmental protection and sustainable development strategies, stable, efficient and environmentally friendly corrosion inhibitors have become the direction of future corrosion inhibitor development. At present, Schiff base compounds and their metal complexes are widely used in the fields of medicine, catalysis, analysis, corrosion, photochromism, etc. Among them, Schiff base corrosion inhibitors have the advantages of simple synthesis steps, low cost, good corrosion inhibition effect, and green environmental protection.

[0005] However, Schiff base corrosion inhibitors as acidifying corrosion inhibitors still face some urgent problems to be solved, mainly because the temperature resistance of Schiff base corrosion inhibitors is not high, generally below 90°C. Summary of the invention

[0006] One of the present invention provides a double condensed Schiff base, the structural formula of which is shown in Formula 1),

[0007]

[0008] The second aspect of the present invention provides a method for preparing a double condensed Schiff base, which comprises the following steps:

[0009] 1) subjecting urea, piperidine and pyridine-4-carboxaldehyde to a Mannich reaction, cooling after the reaction to obtain a solid block, washing the solid block with water, and drying to obtain a product A;

[0010] 2) allowing the product A to undergo a condensation reaction with terephthalaldehyde, filtering, and drying to obtain an oily substance, and washing and drying the oily substance to obtain a product B, wherein the product B is the double condensed Schiff base.

[0011] In a specific embodiment, the molar ratio of urea, piperidine and pyridine-4-carboxaldehyde is (0.7-1):(0.9-1.3):1.

[0012] In a specific embodiment, the molar ratio of urea, piperidine and pyridine-4-carboxaldehyde can be (0.73-1.01):(0.95-1.27):1.

[0013] In a specific embodiment, the molar ratio of urea, piperidine and pyridine-4-carboxaldehyde can be (0.73-1.01):(0.96-1.27):1.

[0014] In a specific embodiment, the molar ratio of the product A to terephthalaldehyde is 1:(0.4-0.6).

[0015] In a specific embodiment, the molar ratio of the product A to terephthalaldehyde is 1:(0.42-0.55).

[0016] In a specific embodiment, in step 1), the reaction is carried out at 65 to 85° C. for 9 to 11 hours.

[0017] In a specific embodiment, in step 2), the reaction is carried out at 20 to 30° C. for 8 to 10 h.

[0018] In one embodiment, in step 1) and step 2), ethanol is independently used as the solvent.

[0019] In one specific embodiment, in step 2), the pH of the reaction environment is adjusted to 2 to 5 with hydrochloric acid.

[0020] The third invention provides a high-temperature acidification corrosion inhibitor, which includes OP-10 (dodecylphenol polyoxyethylene ether-10), DMF (N,N-dimethylformamide) and a double condensed Schiff base as described in one of the present inventions or a double condensed Schiff base prepared by the method described in any one of the second inventions.

[0021] In a specific embodiment, based on the mass of the high temperature acidification corrosion inhibitor as 100%, the content of the double condensed Schiff base is 30% to 50%, the content of the OP-10 is 30% to 50%, and the content of the DMF is 10% to 20%.

[0022] The fourth invention provides the use of the double condensed Schiff base described in one of the present inventions, the double condensed Schiff base prepared by the method described in any one of the second inventions, or the high-temperature acidified corrosion inhibitor described in the third invention in high-temperature corrosion inhibition.

[0023] In a specific embodiment, the elevated temperature is 100°C to 180°C.

[0024] In a specific embodiment, the elevated temperature is 150°C to 180°C.

[0025] Beneficial effects of the present invention:

[0026] The double condensed Schiff base of the present invention is stable at high temperatures of 150°C to 180°C, and has good solubility and compatibility in acid solution after compounding. Compared with the Schiff base in the prior art, the double condensed Schiff base of the present invention can enhance the corrosion inhibition effect of the system at high temperatures, indicating that it can be more closely combined with the metal surface and can significantly reduce the corrosion rate of the acid solution on the pipe column steel at high temperatures of 150°C to 180°C.

[0027] In addition, the raw materials for preparing the double condensed Schiff base of the present invention are easily available and inexpensive, and can generate good economic and social benefits. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with examples, but the examples of the present invention are only exemplary descriptions, and the implementation methods do not constitute limitations of the present invention under any circumstances.

[0029] Synthesis of double condensed Schiff base

[0030] Example 1

[0031] Urea, piperidine and pyridine-4-carboxaldehyde can undergo Mannich reaction to generate Mannich base product A. Product A undergoes condensation reaction with terephthalaldehyde to generate product B, i.e., double condensed Schiff base. The synthesis route is as follows:

[0032]

[0033] 1) Add 2.34 g of urea and 3.07 g of piperidine into a flask, add 50 ml of ethanol as a solvent, and then add 3.21 g of pyridine-4-carboxaldehyde, mix well, and stir the obtained mixture at 65° C. for 10 h to undergo a Mannich condensation reaction; after cooling to room temperature, filter to obtain a white solid, wash the white solid with double distilled water for 3 times, and then dry the white solid in an air oven at 75° C. for 60 min to obtain product A.

[0034] Product A 1H NMR (300MHz, d6-DMSO, δ / ppm): 8.31(d,2H,NAr-H 2,6 ), 7.25(d,2H,NAr-H 3，5 ), 6.42(d,1H,CH-NH), 6.15(d,1H,CH), 5.39(s,2H,NH2), 2.33(s,4H,CH2NCH2), 1.41-1.49(m,6H,CH2CH2CH2).

[0035] 2) 1.01 g of terephthalaldehyde and 2.34 g of product A were added to a three-necked flask, 60 ml of ethanol was added as a solvent, the pH was adjusted to 3 with hydrochloric acid to provide an acidic environment, and the reaction was carried out at 25° C. for 9 h to cause a Schiff condensation reaction; after cooling to room temperature, the lower phase was separated with a separatory funnel to obtain an orange-red oily substance, the orange-red oily substance was washed and separated 3 times with 50 ml of double distilled water and a separatory funnel, then washed and separated 3 times with 20 ml of anhydrous ethanol and a separatory funnel, and finally washed and separated 3 times with 20 ml of ether and a separatory funnel to obtain a red oily liquid product B, which is a double condensed Schiff base.

[0036] Product B 1 H NMR (300MHz, d6-DMSO, δ / ppm): 9.31 (s, 1H, N=CH), 8.56 (d, 2H, Ar-H 2,6 ), 8.17(d,1H,CH-NH), 8.11(s,2H,H-Ar-H), 7.35(d,2H,Ar-H 3,5 ), 6.01(d,1H,CH), 2.42(s,4H,CH2NCH2), 1.40-1.48(m,6H,CH2CH2CH2).

[0037] Example 2

[0038] 1) Add 2.70 g of urea and 3.58 g of piperidine into a flask, add 50 ml of ethanol as a solvent, and then add 3.21 g of pyridine-4-carboxaldehyde, mix well, and stir the obtained mixture at 65° C. for 10 h to undergo a Mannich condensation reaction; after cooling to room temperature, filter to obtain a white solid, wash the white solid with double distilled water for 3 times, and then dry the white solid in an air oven at 75° C. for 60 min to obtain product A.

[0039] 2) 1.14 g of terephthalaldehyde and 2.34 g of product A were added to a three-necked flask, 60 ml of ethanol was added as a solvent, the pH was adjusted to 3 with hydrochloric acid to provide an acidic environment, and the reaction was carried out at 25° C. for 9 h to cause a Schiff condensation reaction; after cooling to room temperature, the lower phase was separated with a separatory funnel to obtain an orange-red oily substance, the orange-red oily substance was washed and separated 3 times with 50 ml of double distilled water and a separatory funnel, then washed and separated 3 times with 20 ml of anhydrous ethanol and a separatory funnel, and finally washed and separated 3 times with 20 ml of ether and a separatory funnel to obtain a red oily liquid product B, which is a double condensed Schiff base.

[0040] Example 3

[0041] 1) 3.24 g of urea and 4.09 g of piperidine were added to a flask, 50 ml of ethanol was added as a solvent, and 3.21 g of pyridine-4-carboxaldehyde was added and mixed evenly. The obtained mixture was stirred at 65° C. for 10 h to undergo a Mannich condensation reaction. After cooling to room temperature, the mixture was filtered to obtain a white solid. The white solid was washed three times with double distilled water, and then the white solid was dried in an air oven at 75° C. for 60 min to obtain product A.

[0042] 2) 1.27 g of terephthalaldehyde and 2.34 g of product A were added to a three-necked flask, 60 ml of ethanol was added as a solvent, the pH was adjusted to 3 with hydrochloric acid to provide an acidic environment, and the reaction was carried out at 25° C. for 9 h to cause a Schiff condensation reaction; after cooling to room temperature, the lower phase was separated with a separatory funnel to obtain an orange-red oily substance, the orange-red oily substance was washed and separated 3 times with 50 ml of double distilled water and a separatory funnel, then washed and separated 3 times with 20 ml of anhydrous ethanol and a separatory funnel, and finally washed and separated 3 times with 20 ml of ether and a separatory funnel to obtain a red oily liquid product B, which is a double condensed Schiff base.

[0043] Example 4

[0044] In step 1), the temperature for the Mannich condensation reaction is 65° C. and the time is 9 h;

[0045] In step 2), the temperature for the Schiff condensation reaction is 20° C. and the time is 8 h.

[0046] The rest is the same as in Example 2.

[0047] Example 5

[0048] In step 1), the temperature for the Mannich condensation reaction is 85°C and the time is 11h;

[0049] In step 2), the temperature for the Schiff condensation reaction is 30° C. and the time is 10 h.

[0050] The rest is the same as in Example 2.

[0051] Example 6

[0052] In step 2), the pH is adjusted to 2 with hydrochloric acid to provide an acidic environment.

[0053] The rest is the same as in Example 2.

[0054] Example 7

[0055] In step 2), the pH is adjusted to 5 with hydrochloric acid to provide an acidic environment.

[0056] The rest is the same as in Example 2.

[0057] Determination of properties of double condensed Schiff base

[0058] 1. Yield

[0059] The yield of product A in Examples 1 to 7 was calculated by the following formula 1):

[0060]

[0061] The theoretical mass of product A is calculated according to the minimum molar amount in the stoichiometric ratio of urea, piperidine and pyridine-4-carboxaldehyde.

[0062] The yield of product B of Examples 1 to 7 is calculated by the following formula 2):

[0063]

[0064] The theoretical mass of product B is calculated according to the minimum molar amount in the stoichiometric ratio of phthalaldehyde and product A.

[0065] The results are shown in Table 1.

[0066] Table 1

[0067]

[0068] 2. Water solubility and acid solubility

[0069] 5.0 g of each of the products B in Examples 1 to 7 was dispersed in 100 ml of ultrapure water and the solubility was observed. The results are shown in Table 2.

[0070] 5.0 g of each of the products B in Examples 1 to 7 were dispersed in 100 ml of 20 wt % hydrochloric acid and their solubility was observed. The results are shown in Table 2.

[0071] Table 2

[0072] Example Solubility in water Solubility in 20% hydrochloric acid Example 1 Poorly soluble Poorly soluble Example 2 Poorly soluble Poorly soluble Example 3 Poorly soluble Poorly soluble Example 4 Poorly soluble Poorly soluble Example 5 Poorly soluble Poorly soluble Example 6 Poorly soluble Poorly soluble Example 7 Poorly soluble Poorly soluble

[0073] High temperature acidification corrosion inhibitor

[0074] Example 8

[0075] The product B of Example 2, OP-10 and DMF were mixed in amounts of 40 wt %, 40 wt % and 20 wt % to obtain a high temperature acidification corrosion inhibitor.

[0076] Example 9

[0077] The product B of Example 2, OP-10 and DMF were mixed in amounts of 30 wt %, 50 wt % and 20 wt % to obtain a high temperature acidification corrosion inhibitor.

[0078] Example 10

[0079] The product B of Example 2, OP-10 and DMF were mixed in amounts of 50 wt %, 40 wt % and 10 wt % to obtain a high temperature acidification corrosion inhibitor.

[0080] Embodiment 11

[0081] The product B of Example 2, OP-10 and DMF were mixed in amounts of 50 wt %, 30 wt % and 20 wt % to obtain a high temperature acidification corrosion inhibitor.

[0082] Example 12

[0083] The product B of Example 2 was replaced by the product B of Example 1, and the rest was the same as Example 8.

[0084] Embodiment 13

[0085] The product B of Example 2 was replaced by the product B of Example 3, and the rest was the same as Example 8.

[0086] Embodiment 14

[0087] The product B of Example 2 was replaced by the product B of Example 4, and the rest was the same as Example 8.

[0088] Embodiment 15

[0089] The product B of Example 2 was replaced by the product B of Example 5, and the rest was the same as Example 8.

[0090] Example 16

[0091] The product B of Example 2 was replaced by the product B of Example 6, and the rest was the same as Example 8.

[0092] Embodiment 17

[0093] The product B of Example 2 was replaced by the product B of Example 7, and the rest was the same as Example 8.

[0094] Performance test of high temperature acidizing corrosion inhibitor

[0095] 1. Temperature resistance test

[0096] 2 wt % of the high temperature acidification corrosion inhibitors of Examples 8 to 17 were added to 20 wt % HCl acid solution, respectively, and the corrosion rate (g / m 2 h), the results are shown in Table 3.

[0097] 2.5 wt% of the high temperature acidification corrosion inhibitors of Examples 8 to 17 were added to 20 wt% HCl acid solution, respectively, and the corrosion rate (g / m 2 h), the results are shown in Table 3.

[0098] 3.0 wt% of the high temperature acidification corrosion inhibitors of Examples 8 to 17 were added to 20 wt% HCl acid solution, respectively, and the corrosion rate (g / m 2 h), the results are shown in Table 3.

[0099] 3.5 wt % of the high temperature acidification corrosion inhibitors of Examples 8 to 17 were added to 20 wt % HCl acid solution, respectively, and the corrosion rate (g / m 2 h), the results are shown in Table 3.

[0100] 4.0 wt% of the high temperature acidification corrosion inhibitors of Examples 8 to 17 were added to 20 wt% HCl acid solution, respectively, and the corrosion rate (g / m 2 h), the results are shown in Table 3.

[0101] 4.5 wt % of the high temperature acidification corrosion inhibitors of Examples 8 to 17 were added to 20 wt % HCl acid solution, respectively, and the corrosion rate (g / m 2 h), the results are shown in Table 3.

[0102] 5 wt % of the high temperature acidification corrosion inhibitors of Examples 8 to 17 were added to 20 wt % HCl acid solution, respectively, and the corrosion rate (g / m 2 h), the results are shown in Table 3.

[0103] According to the results in Table 3, even at 180°C, the maximum corrosion rate of the N80 coupon is only 62.21 g / m 2 h, which can meet the first-level standard of the petroleum and natural gas industry standard SY / T5405-2019, indicating that the high temperature corrosion inhibitor of the present invention can withstand a high temperature of at least 180°C.

[0104] Table 3

[0105]

[0106] 2. Dispersion test

[0107] 5 wt % of the high temperature acidification corrosion inhibitor prepared in Examples 8 to 17 were added to 20 wt % of HCl acid solution to obtain corrosion inhibition acid solution.

[0108] According to the petroleum and natural gas industry standard SY / T5405-2019, the corrosion-inhibiting acid solution was placed at room temperature for 48 hours, and the dispersibility of the corrosion-inhibiting acid solution was observed at 6 hours, 12 hours, 24 hours and 48 hours. The results are shown in Table 4.

[0109] Table 4

[0110]

[0111]

[0112] According to Table 4, the corrosion-inhibiting acid solution has no stratification and no precipitation within 48 hours, which meets the requirements of the standard, indicating that the high-temperature acidification corrosion inhibitor of the present invention has good solubility and dispersibility in the acid solution, and thus has good compatibility.

[0113] 3. Compatibility test

[0114] 5 wt % of the high temperature acidification corrosion inhibitors prepared in Examples 8 to 17 were respectively added to distilled water to obtain corrosion inhibition solutions.

[0115] The corrosion inhibitor was placed at room temperature for 48 hours, and the dispersibility of the corrosion inhibitor was observed at time points of 6 hours, 12 hours, 24 hours and 48 hours. The results are shown in Table 5.

[0116] According to Table 5, the corrosion inhibitor has no stratification and no precipitation within 48 hours, which fully meets the requirements of the standard, indicating that the high temperature acidification corrosion inhibitor of the present invention has good solubility and dispersibility in water, and thus has good compatibility.

[0117] Table 5

[0118]

[0119]

[0120] 4. Test of the effect of dosage on corrosion inhibition performance

[0121] The experimental time was 4h, the corrosion temperature was 180°C, and the hydrochloric acid concentration was 20wt%. According to the 2019 petroleum and natural gas industry standard SY / T5405-2019, the high temperature acidification corrosion inhibitors prepared in Examples 8 to 17 were evaluated for their corrosion inhibition performance on N80 corrosion test pieces under different addition conditions (mass content), that is, the corrosion rate of N80 under different addition conditions was determined. -2 ·h -1 , the experimental results are shown in Table 6.

[0122] It can be seen from Table 6 that with the increase of the amount of corrosion inhibitor, the corrosion rate gradually decreases, but after the addition of 3%, the corrosion rate decreases significantly slower, proving that the improvement of the corrosion inhibitor effect is no longer obvious. For better economic benefits, the optimal usage mass fraction of the corrosion inhibitor can be determined to be 3%.

[0123] Table 6

[0124] Example 0.5％ 1.0％ 2.0％ 3.0％ 4.0％ 5.0％ 6.0％ 7.0％ Example 8 324.95 163.97 77.96 55.38 48.84 57.58 42.01 40.86 Example 9 335.64 175.12 81.54 59.67 51.02 62.21 45.21 42.35 Example 10 329.14 169.57 79.38 58.95 49.68 45.52 45.14 43.33 Embodiment 11 354.21 189.24 91.24 73.67 59.47 51.63 50.08 47.35 Example 12 340.95 196.60 92.25 69.32 52.43 53.15 46.60 44.12 Embodiment 13 326.80 183.12 89.22 59.56 49.40 47.45 43.94 41.98 Embodiment 14 359.13 182.40 98.40 82.70 69.07 53.44 47.25 47.13 Embodiment 15 334.20 169.79 83.52 65.48 58.20 55.18 44.89 42.32 Example 16 324.08 178.25 79.86 58.70 53.86 52.42 46.36 45.10 Embodiment 17 312.64 159.18 69.75 69.28 58.46 56.15 47.30 45.43

[0125] Although the present invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that various changes may be made without departing from the true spirit and scope of the present invention. In addition, the subject matter, spirit and scope of the present invention may be varied to accommodate specific situations, materials, material combinations and methods. All of these changes are included within the scope of the claims of the present invention.

Claims

1. A double condensed Schiff base, the structural formula of which is shown in Formula 1), 2. A method for preparing a double condensed Schiff base, comprising the following steps: 1) subjecting urea, piperidine and pyridine-4-carboxaldehyde to a Mannich reaction, cooling after the reaction to obtain a solid block, washing the solid block with water, and drying to obtain a product A; 2) allowing the product A to undergo a condensation reaction with terephthalaldehyde, filtering, and drying to obtain an oily substance, and washing and drying the oily substance to obtain a product B, wherein the product B is the double condensed Schiff base.

3. The method according to claim 2, characterized in that The mass ratio of the urea, piperidine and pyridine-4-carboxaldehyde is (0.7-1):(0.9-1.3):

1.

4. The method according to claim 2, characterized in that: The mass ratio of the product A to terephthalaldehyde is 1:(0.4-0.6).

5. The method according to claim 2, characterized in that: In step 1), the reaction is carried out at 65 to 85° C. for 9 to 11 hours; and / or In step 2), the reaction is carried out at 20 to 30° C. for 8 to 10 hours.

6. The method according to claim 2, characterized in that In step 1) and step 2), ethanol is independently used as a solvent.

7. The method according to claim 2, characterized in that In step 2), the reaction environment is adjusted to pH 2 to 5 with hydrochloric acid.

8. A high temperature acidification corrosion inhibitor, comprising OP-10, DMF and the double condensed Schiff base according to claim 1 or the double condensed Schiff base prepared by the method according to any one of claims 2 to 7.

9. The high temperature acidification corrosion inhibitor according to claim 8, characterized in that: Taking the mass of the high-temperature acidified corrosion inhibitor as 100%, the content of the double condensed Schiff base is 30% to 50%, the content of the OP-10 is 30% to 50%, and the content of the DMF is 10% to 20%.

10. Use of the double condensed Schiff base according to claim 1, the double condensed Schiff base prepared by the method according to any one of claims 2 to 7, or the high temperature acidification corrosion inhibitor according to claim 8 or 9 in high temperature corrosion inhibition; Preferably, the high temperature is 150°C to 180°C.

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