RU2524527C1 - Method of protecting steel from corrosion in mineralised water-oil media containing carbon dioxide - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method includes adding, to the mineralised water-oil medium containing carbon dioxide, a corrosion inhibitor in the form of N-(2-cyclopent-1-en-1-ylphenyl)-2R-N-phthalimidohexanamide, where R denotes a C² atom configuration, with concentration of 50-200 mg/l.

EFFECT: high degree of protection of steel.

1 tbl, 3 ex

Description

The invention relates to a method for protecting metals from corrosion in mineralized water-oil media by inhibitors and can be used to protect equipment and pipelines in contact with water-oil media containing carbon dioxide in the oil industry from corrosion.

Known methods of protecting steel from corrosion using inhibitors based on aromatic and heterocyclic compounds: the condensation product of benzylamine with urotropine (TU 6-02-1192-79. Corrosion inhibitor BA-6. Introduction. 01.01.80.13 p.); a mixture of alkylbenzylpyridine and a cyclic amine (TU 6-46893387-34-90. Corrosion inhibitor KI-1. Introduced 01.07.90.12 p.); a mixture of derivatives of toluene diisocyanates (TU 6-03-31-81. Corrosion inhibitor TDA. Introduced 01.02.82.13 p.); derivatives of alkipyridinium chlorides (TU 6-01-530-70. Corrosion inhibitor Katapin B-300. Introduction. 01.01.71.13 s.); Quaternary pyridinium salt (TU 6-01-11-15-72. Corrosion inhibitor KPI-3. Introduced 01.02.73.14 p.).

However, these inhibitors do not have a high protection efficiency in mineralized water-oil media containing carbon dioxide.

The closest analogue in structure and effectiveness is the PB-5 corrosion inhibitor, which is a condensation product of aniline and urotropine (TU 6-01-28-92. The PB-5 corrosion inhibitor. Introduction. 01.01.93.11 p.).

The disadvantage of this inhibitor is its low efficiency in mineralized water-oil media containing carbon dioxide.

The claimed technical solution is aimed at improving the effective protection of steel against corrosion in mineralized water-oil media containing carbon dioxide.

The claimed technical solution proposes a method of protecting steel from corrosion in mineralized water-oil environments, including adding a corrosion inhibitor to the mineralized oil-water medium containing carbon dioxide, wherein N- (2-cyclopent-1-ene is used as a corrosion inhibitor) -1-ylphenyl) -2R-N-phthalimidohexanamide, where R is the designation of the configuration of the C ² atom, with a concentration of 50-200 mg / l of the formula:

N- (2-cyclopent-1-en-1-ylphenyl) -2R-N-phthalimidohexanamide is obtained by direct alkenylation of ortho- (cyclopent-1-enyl) aniline with norleucine chloride [Kazaryants (Krasko) SA, Salikhov Sh. M., Abdrakhmanov I.B., Ivanova S.R. Intramolecular cyclization of ortho- (1-cycloalkenyl) anilines I. Synthesis of 2-aryl-substituted 4H-3,1-benzoxazines // Bashkir Chemical Journal. - 2009. - T. 16. - No. 4. - S.19-24].

Tests of the protective effect of N- (2-cyclopent-1-en-1-ylphenyl) -2R-N-phthalimidohexanamide as an inhibitor of steel in mineralized water-oil media containing carbon dioxide were carried out under laboratory conditions by the gravimetric method in accordance with RD 39-0147-276-359-86 “Guidelines for conducting corrosion studies of media, the selection of effective inhibitors and anti-corrosion coatings for the protection of equipment for oil production and collection systems using carbon dioxide in order to increase oil recovery” Bashnipineft, 1987.

As working media, a reservoir water model (MPV) of the composition was used, g / l: NaCl - 140.0; CaCl ₂ - 42.0; CaSO ₄ - 0.5; MgCl ₂ - 8.0; and oil in a ratio of 90:10. The dioxide content in the water-oil medium was 400 mg / L. As witness samples used plates of steel grade 3 (GOST 380-90).

Fat-free and dried to constant weight samples of steel 3 were placed in a working environment for 6 hours at 20 ° C with the addition of the proposed inhibitor and without it. After the aging time, the samples were thoroughly washed in a stream of water, immersed for 5-10 minutes in an alkali solution and again washed with running water and dried to constant weight. Next, the samples were weighed to the nearest 0.0002 g.

The corrosion rate (p), the degree of corrosion protection of steel (Z) was determined in accordance with formulas (1) and (2)

$$P=\frac{m_{\mathrm{one}}-m_2}{S\cdot t},(\mathrm{one})$$

where m ₁ -m ₂ - change in mass, g;

S is the sample area, m ² ;

t is the test time, h

$$Z=\frac{p_{\mathrm{one}}-p_2}{p_{\mathrm{one}}}\mathrm{one\; hundred,}(2)$$

where p ₁ is the corrosion rate in a medium without an inhibitor, g / m ² · h;

p ₂ - corrosion rate in an inhibited medium, g / m ² · h

The essence of the claimed technical solution is confirmed by examples of specific performance.

Example 1

Synthesis of N- (2-cyclopent-1-en-1-ylphenyl) -2R-N-phthalimidohexanamide.

To a solution of 4.67 mmol of ortho- (cyclopent-1-enyl) aniline in CH ₂ Cl _{2 was} added 7.95 mmol of K ₂ CO ₃ and norleucine chloride was pinned with stirring. It was stirred for 24 hours. The product was separated by column chromatography on silica gel (eluent — petroleum ether: ethyl acetate).

Yield 90%. White spherical crystals ,, T _PL 85-87 ° C. Found,%: C 82.00, H 5.99, N 5.49. C ₁₈ H ₁₇ NO. Calculated,%: C 82.10, H6.51, N 5.32, O 6.08. ¹ H NMR Spectrum (CDCl ₃ , δ / ppm, J / Hz): 0.92 (3H, t, J = 6.9, C ⁶ H ₃ ), 1.30 (2H, m, C ⁴ H ₂ ), 1.40 (2H, m, C ⁵ H ₂ ), 1.83 (1H, m, C ^{3 '} H ^a ), 1.89 (1H, m, C ^3' H ^b ), 2, 27 (3H, m, C ⁴ H ₂ , C ³ H ^b ), 2.40 (1H, m, C ³ H ^a ), 2.59 (2H, m, C ^{2 '} H ₂ ), 4.95 ( 1H, dd, J = 10.8, 5.4, C ² H), 5.75 (1H, t, J = 1.8, C ^{5 '} H), 7.09 (1H, t, J = 7.5 , H _p- ), 7.15 (1H, dd, J = 7.5, 1.4, H _m'- ), 7.26 (1H, ddd, J = 8.3, 7.5, 1.4, H _m- ) 7.70 (2H, m, Pht), 7.93 (2H, m, Pht), 8.30 (1H, br s, NH), 8.38 (1H, d, J = 8.3, H _o- ).

¹³ C NMR spectrum (CDCl ₃ , δ / ppm): 13.83 (C ⁶ ), 22.14 (C ⁵ ), 23.31 (C ^{3 '} ), 27.98 (C ³ ), 28 51 (C ⁴ ), 33.60 (C ^{4 '} ), 36.95 (C ^2' ), 55.32 (C ² ), 120.50 (Ar), 123.69 (Ar), 123.94 (Ar), 127.60 (Ar), 127.72 (Ar), 130.73 (C ^{5 '} ), 131.51 (Ar), 134.28 (Ar), 134.55 (Ar), 140, 63 (C ^{1 '} ), 166.66 (C ¹ = O), 167.86 (C = O).

Example 2

Tests of the protective effect of N- (2-cyclopent-1-en-1-ylphenyl) -2R-N-phthalimidohexanamide as an inhibitor of steel were carried out according to the method described above.

In a mineralized water-oil medium containing 400 mg / l of carbon dioxide, the corrosion rate without inhibitor is 0.60 g / m ² · h, and in the presence of 200 mg / l N- (2-cyclopent-1-en-1- ilphenyl) -2R-N-phthalimidohexanamide (hereinafter reagent) - 0.024 g / m ² · h. The degree of corrosion protection under these conditions is 96.0%.

Example 3

Testing the effectiveness of corrosion protection with the prototype (inhibitor PB-5) was carried out analogously to example 2.

The corrosion rate of steel in a mineralized water-oil medium is 0.60 g / m ² · h without a reagent and 0.36 g / m ² · h in the presence of 200 mg / l of the prototype. The degree of protection under these conditions is 40.0%.

Table 1 presents the rest of the test examples of N- (2-cyclopent-1-en-1-ylphenyl) -2R-N-phthalimidohexanamide as an inhibitor of steel corrosion in mineralized water-oil media containing carbon dioxide.

The test results are shown in table 1, indicate the high efficiency of the proposed corrosion inhibitor of steel in mineralized water-oil environments containing carbon dioxide. The highest efficiency is achieved when the inhibitor concentration is from 50 to 200 mg / l (degree of protection 93.7-96.0%). With an increase in the inhibitor concentration above 200 mg / L, the degree of protection does not change significantly, and with a decrease in its concentration below 50 mg / L, a sharp decrease in the degree of protection is observed. In the case of the prototype at a concentration of 200 mg / l, the corrosion rate is 0.36 g / m ² · h and the degree of protection is 40.0%.

Table 1 The effectiveness of N- (2-cyclopent-1-en-1-ylphenyl) -2R-N-phthalimido-hexanamide as a corrosion inhibitor in mineralized water-oil media containing carbon dioxide No. p / p Inhibitor concentration, mg / l The corrosion rate, g / m ² · h Degree of protection, % The control - 0.61 - 2 200,0 0.024 96.0 3 prototype 200,0 0.36 40,0 four 100.0 0,030 95.0 5 50,0 0,038 93.7 6 25.0 0.058 90.3 7 300,0 0,025 95.8

The advantages of the proposed corrosion inhibitor of steel in comparison with the prototype are as follows.

1. A high degree of corrosion protection of N- (2-cyclopent-1-en-1-ylphenyl) -2R-N-phthalimidohexanamide (93.7-96.0%) compared with the prototype (40.0%).

2. The decrease in the corrosion rate of steel in the presence of N- (2-cyclopent-1-en-1-ylphenyl) -2R-N-phthalimidohexanamide by 15-25 times, and in the presence of the prototype - 1.67 times.

3. Effective dosages of the proposed inhibitor are 50-200 mg / l (degree of protection 93.7-96.0%), and in the prototype, even at dosages of 200 mg / l, the degree of protection does not exceed 40.0%.

The results allow us to conclude that the proposed method for protecting steel from corrosion in mineralized water-oil media containing carbon dioxide, which can be used in the oil industry, is highly effective.

Claims (1)

A method of protecting steel from corrosion in mineralized water-oil media containing carbon dioxide, comprising adding a corrosion inhibitor to the mineralized oil-water medium containing carbon dioxide, characterized in that N- (2-cyclopent-1- is used as a corrosion inhibitor) en-1-ylphenyl) -2R-N-phthalimidohexanamide with a concentration of 50-200 mg / l.