Bis-condensed schiff bases and compositions containing the same

Abstract

The present application provides a double condensation Schiff base and a composition containing the same. The structural formula of the double condensation Schiff base is shown as formula 1),

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil exploration, in particular to a double condensation Schiff base used as a high-temperature acidification corrosion inhibitor. BACKGROUND

[0002] With the development of exploration and development technology, deep-ultra deep oil and gas development has become an important replacement field of oil and gas resources. The important problem faced by deep-ultra deep oil and gas development is that the reservoir temperature and water quality salinity increase with the increase of mining depth, resulting in serious corrosion of wellbore. The current hot spot of oil and gas exploration and development is gradually shifting to deep-ultra deep oil and gas reservoirs. These oil and gas reservoirs are mostly characterized by low porosity and low permeability, and high temperature (up to 180℃) and high pressure (bottom hole pressure exceeding 16MPa). The development conditions of oil and gas wells are extremely harsh.

[0003] As an important means to improve single well productivity, acidification operation is widely used in deep-ultra deep oil and gas reservoir development, and the corrosion risk of acid liquid to downhole string will be greatly increased. Oilfield acidification technology not only improves oil and gas production, but also causes a series of string corrosion problems. If the corrosion problem of the string cannot be effectively controlled, not only the string will be out of production due to overhaul, but also the oil and gas well will be scrapped. In recent years, with the increasingly severe mining environment and the increasing mining depth, the method of adding corrosion inhibitor is mainly used to deal with the corrosion problem of the string during acidification.

[0004] In order to meet the needs of environmental protection and sustainable development strategy, stable, efficient and environmentally friendly corrosion inhibitor has become the development direction of future corrosion inhibitor. At present, Schiff base compounds and their metal complexes are widely used in medical field, catalytic field, analysis field, corrosion field, photochromic field and other fields. Among them, the Schiff base corrosion inhibitor has the advantages of simple synthesis steps, low cost, good corrosion inhibition effect and green environmental protection.

[0005] However, the Schiff base corrosion inhibitor as an acidification corrosion inhibitor still faces some problems to be solved, mainly that the temperature resistance of the Schiff base corrosion inhibitor is not high, generally below 90℃. SUMMARY

[0006] One of the present application provides a double condensation Schiff base, the structural formula of which is shown as formula 1),

[0007]

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

[0009] 1) Mannich reaction of urea, piperidine and pyridine-4-formaldehyde, after the reaction is completed, cooling is carried out, a solid block is obtained, the solid block is washed with water, and drying is carried out to obtain product A;

[0010] 2) condensing the product A with p-xylylene formaldehyde, filtering, drying to obtain an oil, washing the oil, drying to obtain product B, which is the double condensation Schiff base.

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

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

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

[0014] In one embodiment, the molar ratio of product A and p-xylylene formaldehyde is 1:(0.4-0.6).

[0015] In one embodiment, the molar ratio of product A and p-xylylene formaldehyde is 1:(0.42-0.55).

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

[0017] In one 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), independently, ethanol is used as the solvent.

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

[0020] The present application III provides a high-temperature acidification corrosion inhibitor, which comprises OP-10 (dodecyl phenol polyoxyethylene ether-10), DMF (N,N-dimethylformamide) and a double condensation Schiff base as described in the present application I or prepared by the method described in the present application II.

[0021] In one embodiment, based on the mass of the high-temperature acidification corrosion inhibitor as 100%, the content of the double condensation 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 application four provides application of the double condensation Schiff base according to the application one, the double condensation Schiff base prepared by the method according to any one of the application two or the high-temperature acidification corrosion inhibitor according to the application three in high-temperature corrosion inhibition.

[0023] In one specific embodiment, the high temperature is 100-180 DEG C.

[0024] In one specific embodiment, the high temperature is 150-180 DEG C.

[0025] The application has the following beneficial effects:

[0026] The double condensation Schiff base of the application is stable in nature at a high temperature of 150-180 DEG C, and has good solubility and compatibility in acid solution after compounding. Compared with the Schiff base in the prior art, the double condensation Schiff base of the application can enhance the corrosion inhibition effect of the system at high temperature, indicating that it can bind more closely to the metal surface and can significantly reduce the corrosion rate of the acid solution on the pipe column steel at a high temperature of 150-180 DEG C.

[0027] In addition, the raw materials for preparing the double condensation Schiff base of the application are easy to obtain and low in price, and can produce good economic and social benefits. DETAILED DESCRIPTION

[0028] The application will be further described below in conjunction with examples, but the examples of the application are only exemplary descriptions, and the embodiment does not constitute a limitation on the application in any case.

[0029] Synthesis of double condensation Schiff base

[0030] Example 1

[0031] Urea, piperidine and pyridine-4-formaldehyde can undergo a Mannich reaction to generate a Mannich base product A, and product A can undergo a condensation reaction with p-phenylenediamine to generate product B, i.e. a double condensation Schiff base, and the synthesis route is shown as follows:

[0032]

[0033] 1) 2.34 g of urea and 3.07 g of piperidine were added to a flask, 50 ml of ethanol was added as a solvent, 3.21 g of pyridine-4-formaldehyde was added, and the mixture was uniformly mixed, and the obtained mixture was stirred at 65 DEG C for 10 h to undergo a Mannich condensation reaction; after cooling to room temperature, filtration was performed to obtain a white solid, the white solid was washed with double-distilled water for 3 times, and then the white solid was dried in an air oven at 75 DEG C for 60 min to obtain product A.

[0034] Synthesis of product A 1H NMR (300 MHz, 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) Add 1.01 g of p-phenylenediamine and 2.34 g of product A into a three-necked flask, add 60 ml of ethanol as solvent, adjust pH to 3 with hydrochloric acid to provide an acidic environment, and react at 25 °C for 9 h to occur Schiff condensation reaction; after cooling to room temperature, separate the lower phase with a separatory funnel to obtain an orange-red oily substance, wash the orange-red oily substance with 50 ml of double distilled water and a separatory funnel and separate 3 times, then wash and separate 3 times with 20 ml of anhydrous ethanol and a separatory funnel, and finally wash and separate 3 times with 20 ml of ethyl ether and a separatory funnel to obtain product B as a red oily liquid, which is a double-condensed Schiff base.

[0036] Product B 1 H NMR (300 MHz, 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 solvent, then add 3.21 g of pyridine-4-carboxaldehyde, mix well, and stir the obtained mixture at 65 °C for 10 h to occur Mannich condensation reaction; after cooling to room temperature, filter to obtain white solid, wash the white solid with double distilled water 3 times, and then dry the white solid in an air oven at 75 °C for 60 min to obtain product A.

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

[0040] Example 3

[0041] 1) In a flask, 3.24 g of urea and 4.09 g of piperidine were added, 50 ml of ethanol was added as solvent, 3.21 g of pyridine-4-carboxaldehyde was added, the mixture was stirred at 65 °C for 10 h to occur Mannich condensation reaction; after cooling to room temperature, filtration was performed to obtain white solid, the white solid was washed with double distilled water for 3 times, then the white solid was dried in an air oven at 75 °C for 60 min to obtain product A.

[0042] 2) In a three necked flask, 1.14 g of p-xylylene-dialdehyde and 2.34 g of product A were added, 60 ml of ethanol was added as solvent, pH was adjusted to 3 with hydrochloric acid to provide acidic environment, Schiff condensation reaction occurred at 25 °C for 9 h; after cooling to room temperature, the lower phase was separated with separating funnel to get orange red oily substance, the orange red oily substance was washed and separated with 50 ml of double distilled water and separating funnel for 3 times, then washed and separated with 20 ml of anhydrous ethanol and separating funnel for 3 times, finally washed and separated with 20 ml of ether and separating funnel for 3 times, product B was obtained as red oily liquid, which was bis-condensed Schiff base.

[0043] Example 4

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

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

[0046] The others were the same as example 2.

[0047] Example 5

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

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

[0050] The others were the same as example 2.

[0051] Example 6

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

[0053] The same as Example 2.

[0054] Example 7

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

[0056] The same as Example 2.

[0057] Performance measurement of the double condensation Schiff base

[0058] 1. Yield

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

[0060]

[0061] wherein the theoretical mass of the product A was calculated based on the minimum molar amount in the stoichiometric ratio of urea, piperidine and pyridine-4-carboxaldehyde.

[0062] The yield of the product B in Examples 1 to 7 was calculated by the following Formula 2):

[0063]

[0064] wherein the theoretical mass of the product B was calculated based on the minimum molar amount in the stoichiometric ratio of benzene dicarboxaldehyde and the 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 the product B in Examples 1 to 7 was respectively dispersed in 100 ml of ultrapure water, and the solubility was observed, and the results are shown in Table 2.

[0070] 5.0 g of the product B in Examples 1 to 7 was respectively dispersed in 100 ml of hydrochloric acid having a concentration of 20 wt%, and the solubility was observed, and the results are shown in Table 2.

[0071] Table 2

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

[0073] High-temperature acidification corrosion inhibitor

[0074] Example 8

[0075] The product B of Example 2, OP-10 and DMF were mixed in the amount of 40wt%, 40wt% and 20wt% 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 the amount of 30wt%, 50wt% and 20wt% 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 the amount of 50wt%, 40wt% and 10wt% to obtain a high temperature acidification corrosion inhibitor.

[0080] Example 11

[0081] The product B of Example 2, OP-10 and DMF were mixed in the amount of 50wt%, 30wt% and 20wt% 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 others were the same as Example 8.

[0084] Example 13

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

[0086] Example 14

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

[0088] Example 15

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

[0092] Example 17

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

[0094] Performance test of high temperature acidification corrosion inhibitor

[0095] 1. Temperature resistance test

[0096] The high-temperature acidizing corrosion inhibitors of Examples 8 to 17 were added to 20wt% HCl acid liquid respectively at 2wt%, and the corrosion rate (g / m2·h) of N80 coupon was determined at 120℃ according to the 2019 oil and gas industry standard SY / T5405-2019, and the results are shown in Table 3. 2

[0097] The high-temperature acidizing corrosion inhibitors of Examples 8 to 17 were added to 20wt% HCl acid liquid respectively at 2.5wt%, and the corrosion rate (g / m2·h) of N80 coupon was determined at 130℃ according to the 2019 oil and gas industry standard SY / T5405-2019, and the results are shown in Table 3. 2

[0098] The high-temperature acidizing corrosion inhibitors of Examples 8 to 17 were added to 20wt% HCl acid liquid respectively at 3.0wt%, and the corrosion rate (g / m2·h) of N80 coupon was determined at 140℃ according to the 2019 oil and gas industry standard SY / T5405-2019, and the results are shown in Table 3. 2

[0099] The high-temperature acidizing corrosion inhibitors of Examples 8 to 17 were added to 20wt% HCl acid liquid respectively at 3.5wt%, and the corrosion rate (g / m2·h) of N80 coupon was determined at 150℃ according to the 2019 oil and gas industry standard SY / T5405-2019, and the results are shown in Table 3. 2

[0100] The high-temperature acidizing corrosion inhibitors of Examples 8 to 17 were added to 20wt% HCl acid liquid respectively at 4.0wt%, and the corrosion rate (g / m2·h) of N80 coupon was determined at 160℃ according to the 2019 oil and gas industry standard SY / T5405-2019, and the results are shown in Table 3. 2

[0101] The high-temperature acidizing corrosion inhibitors of Examples 8 to 17 were added to 20wt% HCl acid liquid respectively at 4.5wt%, and the corrosion rate (g / m2·h) of N80 coupon was determined at 170℃ according to the 2019 oil and gas industry standard SY / T5405-2019, and the results are shown in Table 3. 2

[0102] The high-temperature acidizing corrosion inhibitors of Examples 8 to 17 were added to 20wt% HCl acid liquid respectively at 5wt%, and the corrosion rate (g / m2·h) of N80 coupon was determined at 180℃ according to the 2019 oil and gas industry standard SY / T5405-2019, and the results are shown in Table 3. 2 ​​​​​​​

[0103] According to the results of Table 3, even at 180℃, the corrosion of the N80 coupon is at most 62.21g / m 2 h, which can meet the first level standard of the oil and gas industry standard SY / T5405-2019, indicating that the high-temperature corrosion inhibitor of the application can at least withstand a high temperature of 180℃.

[0104] Table 3

[0105]

[0106] 2. Dispersion test

[0107] 5wt% of the high-temperature acidizing corrosion inhibitor prepared in Examples 8 to 17 was added to 20wt% of HCl acid solution, respectively, to obtain a corrosion inhibitor acid solution.

[0108] According to the oil and gas industry standard SY / T5405-2019, the corrosion inhibitor acid solution was placed at room temperature for 48h, and the dispersion of the corrosion inhibitor acid solution was observed at time points of 6h, 12h, 24h and 48h, and the results are shown in Table 4.

[0109] Table 4

[0110]

[0111]

[0112] According to Table 4, the corrosion inhibitor acid solution has no stratification and no precipitation within 48h, which meets the requirements of the standard, indicating that the high-temperature acidizing corrosion inhibitor of the application has good solubility and dispersion in the acid solution, and thus has good compatibility.

[0113] 3. Compatibility test

[0114] 5wt% of the high-temperature acidizing corrosion inhibitor prepared in Examples 8 to 17 was added to distilled water, respectively, to obtain a corrosion inhibitor solution.

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

[0116] According to Table 5, the corrosion inhibitor solution has no stratification and no precipitation within 48h, which completely meets the requirements of the standard, indicating that the high-temperature acidizing corrosion inhibitor of the application has good solubility and dispersion 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] Under the conditions of an experimental time of 4h, a corrosion temperature of 180℃, and a hydrochloric acid concentration of 20wt%, the corrosion inhibition performance of the high-temperature acidizing corrosion inhibitor prepared according to the evaluation examples 8 to 17 of the 2019 oil and natural gas industry standard SY / T5405-2019 on N80 corrosion test pieces under different dosages (mass content) was tested, that is, the corrosion rate / g·m of N80 under different dosages was determined. -2 -1 The experimental results are shown in Table 6.

[0122] As can be seen from Table 6, as the dosage of the corrosion inhibitor increases, the corrosion rate gradually decreases, but after the dosage of 3%, the speed of the decrease in the corrosion rate is obviously slow, proving that the effect of the corrosion inhibitor has no longer improved obviously, and in order to achieve better economic benefits, the optimal use mass fraction of the corrosion inhibitor can be determined as 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 Example 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 Example 13 326.80 183.12 89.22 59.56 49.40 47.45 43.94 41.98 Example 14 359.13 182.40 98.40 82.70 69.07 53.44 47.25 47.13 Example 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 Example 17 312.64 159.18 69.75 69.28 58.46 56.15 47.30 45.43

[0125] Although the present application has been described with reference to specific embodiments, it is understood that various changes can be made without departing from the true spirit and scope of the application. In addition, various changes can be made to the subject matter, spirit and scope of the application to adapt it to specific situations, materials, compositions of matter and methods. All such changes are intended to be included within the scope of the claims of the present application.​

Claims

1. A double condensation Schiff base, having a structural formula as shown in formula 1. Formula 1). 2.A method for preparing the double condensation Schiff base according to claim 1, comprising the following steps: 1) subjecting urea, piperidine and pyridine-4-carboxaldehyde to a Mannich reaction, and after the reaction is completed, cooling to obtain a solid block, washing the solid block with water, and drying to obtain product A; 2) subjecting the product A to a condensation reaction with p-xylylformaldehyde, filtering and drying to obtain an oil, washing and drying the oil to obtain product B, which is the double condensation Schiff base.

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

1.

4. The method of claim 2, wherein, The mass ratio of the product A and p-xylylformaldehyde is 1: (0.4-0.6).

5. The method of claim 2, wherein, In step 1), the reaction is carried out at 65 to 85 °C for 9 to 11 h; and / or In step 2), the reaction is carried out at 20 to 30 °C for 8 to 10 h.

6. The method of claim 2, wherein, In steps 1) and 2), ethanol is independently used as the solvent.

7. The method of claim 2, wherein, 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 condensation Schiff base according to claim 1 or prepared by the method according to any one of claims 2 to 7.

9. The high temperature acidizing corrosion inhibitor of claim 8, wherein, The content of the double condensation 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%, based on 100% of the mass of the high-temperature acidification corrosion inhibitor. 10.Use of the double condensation Schiff base according to claim 1, the double condensation 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. The high temperature is 150 °C to 180 °C.

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