RU2706927C1 - Corrosion inhibitor - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to protection of metals from corrosion and can be used for protection of gas and oil field equipment and oil transportation pipelines operating in highly mineralized hydrogen sulphide-containing media. Corrosion inhibitor contains, as an active base, imidazolinone derivatives of general formula,where R is CH(1), CHOCH(2).EFFECT: wider range of corrosion inhibitors.1 cl, 2 tbl, 9 ex

Description

The invention relates to the field of producing corrosion inhibitors for gas and oilfield equipment and oil transportation pipelines operating in highly mineralized hydrogen sulfide-containing media, and in particular to a method for producing an active base of inhibitors - derivatives of nitrogen-containing heterocycles - imidazolinones.

It is known the use of a corrosion inhibitor in a hydrogen sulfide medium based on hydrochlorides of aminoparaffins (AS No. 652315, ЕВВ 43/00, 1979).

However, the disadvantage of the claimed inhibitor is a low protective effect at a dosage of up to 100 mg / L.

A corrosion inhibitor is also known for protecting equipment in hydrogen sulfide-containing environments, in which, as an active base, is the product of the interaction of one mole of fatty acid with the number of carbon atoms C ₈ -C ₂₀ and 0.1-1 mol of aminoparaffins with the number of carbon atoms C ₈ -C ₂₀ in the interaction ratio of 10 ÷ 50 (A.S. No. 2061091, C23F 11/00, 1996).

The disadvantages of the corrosion inhibitor are not sufficiently high protective effect at a dosage of 50 ml / l, as well as the use of methyl alcohol, which has a low boiling point and is used in an amount of 80 ml per 10 g of active base.

Structurally similar (prototypes) are corrosion inhibitors containing, as an active base, a mixture of modified imidazolines with aldimines or Schiff bases (Patent RU 2394817, C23F 11/14, 2010).

The disadvantages of these corrosion inhibitors is not high enough efficiency at low dosages, limited raw materials.

The objective of the invention is the development of a method of producing a corrosion inhibitor and the expansion of the range of corrosion inhibitors used in highly mineralized environments.

The problem is solved in that the derivatives of five-membered heterocycles, imidazolinones of the general formula, are used as the active base of corrosion inhibitors.

where R-C ₆ H ₅ (1), C ₆ H ₄ OCH ₃ (2)

The invention consists in the creation of a corrosion inhibitor containing, as an active base, 2-arylidenehydrazinoimidazolinones-4, obtained on the basis of aminoguanidine:

where R-C ₆ H ₅ (1), C ₆ H ₄ OCH ₃ (2)

The preparation of compounds is illustrated by the following examples.

Example 1. Synthesis of 1-aryl-4-chloroacetylguanylhydrazones of aromatic aldehydes

1-Aryl-4-chloroacetylguanylhydrazones of aromatic aldehydes are obtained in two stages. At the first stage, 40 ml of absolute ethanol, 0.01 mol of aminoguanidine, 0.01 mol of the corresponding aldehyde are charged into a three-necked flask equipped with a mechanical stirrer, reflux condenser and thermometer, nitrogen supply tube. The reaction mixture is acidified with hydrochloric acid to pH = 3. The reaction is carried out for 4 hours at the boiling point of the reaction mixture. The product is precipitated into distilled water, washed and dried, and then recrystallized from ethanol.

Get guanylhydrazone benzaldehyde hydrochloride, yield 91%, melting point 164 ... 165 ° C; guanylhydrazone hydrochloride n-methoxybenzaldehyde, yield 93%, melting point 183 ... 184 ° С.

In the second stage, chloroacetylation of 1-arylguanylhydrazones is carried out. In a three-necked flask equipped with a mechanical stirrer, reflux condenser and thermometer, 6.9 g (0.035 mol) of benzaldehyde guanylhydrazone hydrochloride, 4.5 g (0.04 mol) of chloroacetyl chloride, 3.3 g (0.04 mol) of acetate are charged with stirring sodium and 5 ml of glacial acetic acid. The reaction mixture is heated to 40 ... 50 ° C. After lowering the temperature, the reaction mixture is treated with diisopropyl ether and the precipitate formed is filtered off, which is recrystallized from ethanol.

Get 4-chloroacetylguanylhydrazone benzaldehyde, yield 89%, melting point 147 ... 148 ° C; 4-chloroacetylguanylhydrazone p-methoxybenzaldehyde, yield 80%, melting point 168 ... 169 ° C.

Example 2. Obtaining five-membered heterocycles.

0.05 mol of 1-aryl-4-chloroacetylguanylhydrazone and 10 ml of pyridine are charged into a two-necked flask equipped with a mechanical stirrer and reflux condenser. The reaction mixture is boiled for 1 hour. After cooling, the precipitate formed is filtered off, washed with water and acetone, and recrystallized from glacial acetic acid.

Physico-chemical characteristics of 2-benzylidenehydrazino-imidazolinone-4 (compound 1):

Yield: 90%.

T. pl. ° C: 290 ... 292.

IR spectrum, cm ^-1 : 830, 1385, 1485, 1620, 1710, 3365.

Mass spectrum, m / z: 202, 113, 90, 84.

Physico-chemical characteristics of 2-n-methoxybenzylidene-hydrazinoimidazolinone-4 (compound 2): Yield: 92%. T. pl. ° C: 266 (decomp.).

IR spectrum, cm ^-1 : 840, 1390, 1480, 1645, 1710, 3375. Mass spectrum, m / z: 232, 113, 84, 42.

Example 3. Tests of the claimed corrosion inhibitor. The tests were carried out according to the program given in GOST 9.905-82, using two methods.

In the electrochemical method, tests to determine the density of the corrosion current corresponding to the corrosion rate were carried out on a PI-50-1 potentiostat in an electrochemical cell with a test electrode made of St20 steel and a silver chloride comparison electrode equipped with a platinum auxiliary electrode at a concentration of 100 mg / l in a model and acidic (pH = 3) environment. The density of the corrosion current was determined by extrapolating the Tafel section to the value of the corrosion potential on the polarization curve. The protective effect of the compounds was evaluated by comparing densities recorded in uninhibited and inhibited media.

With the gravimetric method, the tests were carried out in an apparatus with a mixing device with a flow velocity of the test medium of 1.0 m / s on samples made of steel grade 20.

The results of the experiments are presented in table 1.

Example 4

A corrosion inhibitor is prepared as follows; a mixture of 10 g of the active base (compound 1) 5 g of AF-9-9 brand neonol and 85 g of solvent (bottoms of butyl alcohols) are stirred at a temperature of 30-40 ° C for one hour (product 1).

Example 5

A corrosion inhibitor is prepared as follows; a mixture of 20 g of the active base (compound 1), 4 g of neonol AF-9-10 and 85 g of solvent (bottoms of butyl alcohols) are stirred at a temperature of 40-45 ° C for one hour (product 2).

Example 6

A corrosion inhibitor is prepared as follows; a mixture of 12 g of the active base (compound 1), 5 g of neonol AF-9-10 and 90 g of solvent (bottoms of butyl alcohols) are stirred at a temperature of 40-45 ° C for one hour (product 3).

Example 7

A corrosion inhibitor is prepared as follows; a mixture of 10 g of the active base (compound 2), 5 g of neonol AF-9-9 and 85 g of solvent (bottoms of butyl alcohols) are stirred at a temperature of 30-40 ° C for one hour (product 4).

Example 8

A corrosion inhibitor is prepared as follows; a mixture of 20 g of the active base (compound 2), 4 g of AF-9-10 brand neonol and 85 g of solvent (bottoms of butyl alcohols) are stirred at a temperature of 40-45 ° C for one hour (product 5).

Example 9

A corrosion inhibitor is prepared as follows; a mixture of 12 g of the active base (compound 2), 5 g of neonol AF-9-10 and 90 g of solvent (bottoms of butyl alcohols) are stirred at a temperature of 40-45 ° C for one hour (product 6).

Table 2 presents the test results of products - corrosion inhibitors for protective activity. Studies were carried out according to the method described in example 3.

Thus, the claimed compounds have a protective ability, and the results indicate the promise of using imidazolinone derivatives as an active base for corrosion inhibitors.

Claims (3)

A corrosion inhibitor containing five-membered nitrogen-containing heterocyclic compounds of the general formula as an active base

, where R is C ₆ H ₅ (1), C ₆ H ₄ OCH ₃ (2)