RU2415970C2 - Inhibitor of carbonic-acidic corrosion of steel - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention can be used at protection of pipelines and equipment in oil industry from corrosion. To protect metals in mineralised mediums containing carbon dioxide there is used 4-methyl-2.6-di-(1¹-methyl-2¹-buthenyl)aniline. Degree of protection from corrosion in mineralised mediums comes to 68.0-97.9 %.

EFFECT: upgraded efficiency of protection of metals from corrosion.

1 tbl, 3 ex

Description

The invention relates to a method of protecting metals from corrosion in mineralized environments by inhibitors and can be used in corrosion protection of equipment in the oil industry in contact with waste water and emulsions containing carbon dioxide.

Many derivatives of aromatic and heterocyclic compounds are known as corrosion inhibitors: the condensation product of benzylamine with urotropine (TU 6-02-1192-79); Corrosion inhibitor BA-6. Enter 01.01.80.13 s.); a mixture of alkylbenzylpyridine and a cyclic amine (TU 6-46893387-34-90); Corrosion inhibitor KI-1. Introduction 01.07.90.90 s.); condensation product of aniline and urotropin (TU 6-01-28-92. Corrosion inhibitor PB-5. Introduction 01.01.93.11 p.); derivatives of alkyl pyridinium 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 environments containing carbon dioxide.

The closest analogue in structure and effectiveness is the TDA corrosion inhibitor, which is a mixture of derivatives of toluene diisocyanates (TU 6-03-31-81. TDA corrosion inhibitor. Introduced 01.02.82.13 p.)

The disadvantage of this inhibitor is its low efficiency in environments containing carbon dioxide.

The claimed technical solution is aimed at increasing the effectiveness of corrosion inhibitors of steel in mineralized environments containing carbon dioxide.

In the claimed technical solution, this is achieved by using 4-methyl-2,6-di- (1 ^1- methyl-2 ¹ -butenyl) -aniline as a corrosion inhibitor, which is obtained by direct alkenylation of p-toluidine with piperylene in the presence of aluminum chloride (Abdrakhmanov IB Amino-Kleisen rearrangement and conversion of orthoalkenylarylamines. - Dis .... Doctor of Chemical Sciences. - Ufa: Ural Scientific Center, Institute of Chemistry, Academy of Sciences of the USSR, 1989).

The protective effect of 4-methyl-2,6-di- (1 ^1- methyl-2 ¹ -butenyl) -aniline as an inhibitor of steel corrosion in media containing carbon dioxide was tested under laboratory conditions in accordance with RD 39-0147276- 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 to enhance oil recovery”, Bashnipineft, 1987.

As working media used models of produced water (MPV) composition, g / l: NaCl - 140; CaCl ₂ - 42; MgCl ₂ - 8; CaSO ₄ - 0.5. The pH of MPV ranged from 5.5 to 6.0. The CO ₂ content was 200-500 mg / L. Samples of steel grade 3 (GOST 380-90) were used as witness samples.

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 inventive reagent 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)

where m ₁ -m ₂ - change in mass, g;

S is the sample area, m ² ;

t is the test time, h

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

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

Example 1

Synthesis of 4-methyl-2,6-di- (1 ^1- methyl-2 ^1- butenyl) aniline.

To 0.5 moles of p-toluidine in a solution of 50 ml of benzene, 2.5 moles of piperylene and 0.9 moles of aluminum chloride were added. The resulting mixture was thermostated at a temperature of 130 ° C for 5 hours. Received 60 g (99%) of 4-methyl-2,6-di- (1 ^1- methyl-2 ^1- butenyl) aniline - an oily liquid with so on. 137 ° / 2 mmHg

Found,%: C 84.96; H 9.87; N, 4.52; C ₂₁ H ₃₁ N.

Calculated: C 84.85; H 10.43; N, 4.71.

IR: 980.1680, 3320, 3410.

Nuclear Magnetic Resonance Spectrum H, (CDCI, ppm, 1, Hz): 1.25 d (9H, 3CH ₃ ); 1.58 d (9H, 3CH ₃ ); 3.23 m (3H, 3CH); 3.42 s (2H, NH ₂ ); 5.38 m (6H, 3CH-CH); 6.58 C (2H, Ar).

Example 2

Testing the effectiveness of the protective action of 4-methyl-2,6-di- (1 ¹ methyl-2 ^1- butenyl) aniline as an inhibitor of steel corrosion was carried out according to the above procedure.

In an MPV containing 200 mg / L CO ₂ , the corrosion rate without inhibitor is 0.875 g / m ² h, and in the presence of 100 mg / L 4-methyl-2,6-di- (1 ¹ -methyl-2 ¹ -butenyl ) aniline (hereinafter reagent) - 0.018 g / m ² hours

The degree of corrosion protection under these conditions is 97.9%.

Example 3

Tests of the effectiveness of the corrosion protection of the prototype (TDA inhibitor) was carried out analogously to example 2.

The corrosion rate of steel in MPV with a CO ₂ content _of 200 mg / l is 0.875 g / m ² h without reagent and 0.482 g / m ² h in the presence of 100 mg / l prototype. The degree of protection under these conditions is 44.9%.

The table shows the rest of the test examples of the claimed compounds as corrosion inhibitors of steel.

The test results shown in the table indicate the high efficiency of the claimed compounds as corrosion inhibitors of steel in mineralized environments containing carbon dioxide, the highest efficiency is achieved at a concentration of the claimed compounds from 30 to 100 mg / L. With an increase in the concentration of the compound above 100 mg / L, the degree of protection does not change significantly, and when its concentration drops below 30 mg / L, a sharp decrease in the degree of protection is observed. In the case of the prototype at a concentration of 100 mg / l, the corrosion rate is 0.272-0.482 g / m ² h and the degree of protection is 36.0-44.9%.

The advantages of the claimed compounds as an inhibitor of corrosion of steel compared with the prototype are as follows.

1. a high degree of corrosion protection 4-methyl-2,6-di- (1 ^1- methyl-2 ¹ butenyl) aniline (68.0-97.9%) compared with the prototype (36.0-44.9%).

2. The decrease in the corrosion rate of steel in the presence of 4-methyl-2,6-di- (11-methyl-21-butenyl) aniline is 3-11 times, and in the presence of the prototype - 1.56-1.81 times.

3. Effective dosages of the claimed compounds are 30-100 mg / l (degree of protection 68.0-97.9%), and in the prototype at dosages of 100 mg / l, the degree of protection does not exceed 44.9%.

The technical and economic advantage of the proposed inhibitor is its high efficiency in mineralized environments containing carbon dioxide.

The results obtained allow us to conclude that the claimed compound is an effective inhibitor of steel corrosion in mineralized environments containing carbon dioxide, i.e. may find application in the oil industry.

Table The effectiveness of 4-methyl-2,6-di- (1 ^1- methyl-2 ^1- butenyl) aniline as an inhibitor of carbon dioxide corrosion of steel №№ Dosage, Content Speed Power examples mg / l CO ₂ , mg / l corrosion, g / m ² h protection,% Control 1 200 0.875 Control 2 300 0.728 Control 3 400 0.647 Control 4 500 0.425 2 one hundred 200 0.018 97.9 3 prototype one hundred 200 0.482 44.9 four fifty 200 0.014 84.0 5 thirty 200 0.021 76.0 6 one hundred 300 0.023 96.0 7 fifty 300 0.131 82.0 8 thirty 300 0.189 74.0 9 one hundred 400 0.039 94.1 10 fifty 400 0.13 79.9 eleven thirty 400 0.182 71.9 12 one hundred 500 0.034 92.0 13 fifty 500 0.093 78.1 fourteen thirty 500 0.136 68.0 15 prototype one hundred 300 0.415 43.0 16 prototype one hundred 400 0.389 39.9 17 prototype one hundred 500 0.272 36.0

Claims (1)

The use of 4-methyl-2,6-di- (1 ^1- methyl-2 ^1- butenyl) aniline as an inhibitor of carbon dioxide corrosion of steel.