CS261597B1 - Mixed evaporation inhibitor of corrosion of iron and its alloys - Google Patents

Abstract

The solution relates to a metal corrosion inhibitor for temporary protection of metal products made of iron and its alloys against corrosion during their, production, transportation* storage and operation. The purpose of the solution is an effective metal corrosion inhibitor for temporary protection, the essence of which lies in the fact that it contains . from 85 to 99 wt. % of 2-aminoethanol benzoate and from 1 to 15 wt. % of a mixture of alkylamine, alkylpropylenediamine and alkyltripropylenetetramine, where the alkyl is formed from 15 to 25 wt. % of ci ^33, from 50 to 60 wt. % of ΟχθΙΗγ and from 15 to 35 wt. % of C18H35. The purpose of the solution is also to find the optimal concentration of the inhibitor in the solvent for application in the form of a solution. In this case, the mass concentration of the inhibitor is from 0.01 to 30 wt. %, preferably 0.8 to 8 wt. %.

Description

The present invention relates to a mixed evaporative corrosion inhibitor of iron and its alloys in approximately neutral aqueous environments, particularly atmospheric conditions.

The effect of corrosion occurring in an approximately neutral aqueous environment is markedly unfavorable for iron and iron alloy products, since corrosion pro- ducts are formed on their surface. products that depreciate them functionally and visually. In order to reduce or eliminate these negative phenomena, a number of corrosion protection methods and means are used in products, of which the use of evaporative type metal corrosion inhibitors is of great importance.

Most of the known evaporative corrosion inhibitors are characterized by high inhibitory activity, but only in the case of the protection of finely worked surfaces, especially polished ·

In the case of roughly treated surfaces, the inhibitory activity is significantly lower or the inhibitors lose their function completely. These include evaporative inhibitors based on the anion of nitrous acid and benzoic acid, especially dicyclohexylamine or ammonium benzoate, and a number of mixed types of inhibitors including, for example, urea, hexamethylenetetramine and sodium nitrite. Moreover, many of these inhibitors are used on an industrial scale only to a limited extent for their hygienic defects.

The aforementioned drawbacks of the prior art in this field are largely eliminated by a mixed evaporative corrosion inhibitor of iron and its 2-aminoethanol benzoate alloys and a mixture of alkylamine, alkyl propylenediamine and alkyltripropylenetetramine according to the invention, characterized in that and from 1 to 15% by weight of a mixture of an alkylamine (I), an alkyl propylenedlamine (II) and an alkyltrlpropylenetetramine (III) of the general formulas (I) with R-11¾ ( II) R - NH - (CH3) 2 - 1 '

wherein R is from 15 to 25% by weight ^ 16 ^ 3 » ⁵⁸ 50 to 60% by weight ^C 18 ^ 7 ^{and up to} 35% by weight

According to the invention, a mixture of an alkylamine, an alkyl propylene amine and an alkyltrl propylene tetramine is understood to be the product of the addition of acrylonitrile to octadeoylamine and the subsequent hydrogenation of the resulting adduct.

It was an object of the invention to find an optimal inhibitor concentration in a solvent for solution application. In this case, the inhibitor comprises from 0.01 to 30% by weight, preferably 0.8 to 8% by weight of the active ingredients, 70 to 99.99% by weight of a solvent, for example water, ethanol or dimethyl ketone, individually or in a mixture. Using this concentration, an inhibitor-2 layer of 0.05 to 3.5 g / cm @ 2 is formed on the treated surface after evaporation of the solvent.

The corrosion inhibitor according to the invention shows very good inhibitory activity against corrosion of iron and its alloys, it is hygienic safe, well soluble and volatile even at low temperatures.

It is preferably applied in the form of an aqueous or alcoholic solution, impregnating the packaging material, powder or aerosol. The solution can be applied to products by painting, dipping, spraying or aerosolizing.

The invention, its effects and uses are explained in more detail below on specific examples of its composition and use.

- 3 Table 1

281,597 provides five examples of compositions of a mixed inhibitor of the invention.

Inhibitor components% by weight of the components Example

AND

- 2-Aminoethanol benzoate 99

- a mixture of amines (I), (II) and (III) 1 wherein R is 20% by weight ^ 3.5 ^ 33 »55% by weight ⁰ 18¾7 ^{and iano} ' ^t · ^

BC

95

D * E

85

10 a mixture of amines (I), (II) and (III) where R is 25% by weight ^ 5 ^ 33. * θθ% by weight

^θ ^ γ and 15 wt%

2 1 5

Electrochemical measurement of corrosion of metal and monitored approximately neutral aqueous medium - C (R @ ₂ S0) «= 0.005 mol.1 ^- ^ - inhibition rate was observed for all listed examples of the inhibitor composition. The inhibition coefficient, expressed as the ratio of the mean reduced corrosion rate in the presence of 1 wt% inhibitor to the mean non-reduced rate of corrosion in an approximately neutral aqueous medium for class III steel - according to CSS 41 1373 - was in the range from 0.90 to 0.96.

Example 1

Mixture containing 95 wt.% 2-aminoethanol benzoate and 5 wt. % of the mixture of amines (I), (II), (III) according to Example C in Table 1 was dissolved in water-ethanol 1: 1 to a solution containing 3 wt% inhibitor. Steel samples were loaded into this solution

- 4 2B1 S97

After evaporation of the solvent, the basis weight of the inhibitor was determined to be 0.6-0.2 g.m. The samples were then tested according to Annex 02 of CSN 03-8205 / ST SEV 992/78 and the results were compared with the samples immersed in an aqueous solution containing 3% by weight of 2-aminoethanol benzoate. Mixed inhibitor-inhibited samples remained free of corrosion after 12 test cycles, while protected with 2-aminoethanol benzoate showed rust formation after 3 cycles ·

Example 2

A mixture of 98% by weight of 2-aminoethanol benzoate and 2% by weight of a mixture of amines (I), (II) and (III) according to Example D in Table 1 was dissolved in ethanol-water in a 1: 1 by volume ratio to 5%. solution. Samples of 11373 steel with a blasted surface for 60 s were introduced into this solution. After evaporation of the solvent, the inhibited samples were tested in the same manner as in Example 1 and showed a similar effect after 10 test cycles.

Example 3

A mixture of 90% by weight of 2-aminoethanol benzoate and 10% by weight of a mixture of amines (I), (II) and (III) according to Example B in Table 1 was sprayed with a jet of 45-2 ° C hot air onto steel samples. 11373 with a blasted surface, placed in a room temperature room. After 10 minutes of aerosolization, a sample weight of inhibitor in the range of 1.4 to 2.2 g.m was found on samples —2. In a test similar to the previous examples, rust inhibited samples were not found after 9 test cycles.

Example 4

A mixed inhibitor of 85% by weight of 2-aminoethanol benzoate and 15% by weight of the mixture of amines (I), (II) and (III) of Example E in Table 1 was dissolved in ethanol to a solution containing

5,261,597 wt% inhibitor. The wrapping paper was impregnated with this solution. After evaporation of the solvent, the basis weight of the inhibitor was found to be 14-16 g.m. In the test according to CSN 03 8205 / ST SEV 992/78, Annex 02, the first occurrence of rust was detected on the blasted surface of 11373 carbon steel after more than 10 cycles, while on the blasted surface of the same steel, protected by packaging material containing mixed sodium nitrite , urea and sodium benzoate had already been corroded after 6 cycles.

The inhibitor according to the invention can be used to protect all ferrous products from corrosion in all the uses mentioned.

Claims (2)

lo A mixed evaporative corrosion inhibitor of iron and its 2-aminoethanol benzoate alloys and a mixture of alkylamine, alkyl propylenediamine and alkyltripropylenetetramine, characterized in that it contains from 85 to 99% by weight of 2-aminoethanol benzoate HgN - CHgCHg - ΟΟΟΟθΗ ^ and from 1 to 15 wt% of a mixture of alkylamine (I), alkyl propylenediamine (II) and alkyltripropylenetetramine. (III) general formulas R = NHg CD R - NH - (0¾) ^ - 1¾ ® R-H- (CH3) 4-NH- (CH3) - 11 ' I (0¾¾ - 0¾ where R is from 15 to 25% by weight ^from 50 to 60% by weight ^ 18¾ 7 15 35 by weight ·% · 2. Inhibitor according to claim 1, characterized in that from 0.01 to 30% by weight, preferably from 0.8 to 8% by weight, of the active ingredients comprises 70 to 99.99% by weight of a solvent, for example water, ethanol. or dimethyl ketone, individually or in admixture.