CS268624B1 - Corrosion inhibitor - Google Patents

Abstract

The solution represents a formulation of a corrosion inhibitor for means of temporary protection of metal materials. These means are used during the production, transportation, storage and use of metal products, mainly iron and its alloys. The corrosion inhibitor is prepared by reacting 10 to 35 parts by weight of an alkylamine with 12 to 22 carbon atoms and 5 to 40 parts by weight of a product of direct aminolysis of natural fats such as sunflower oil, rapeseed oil, palm kernel oil, coconut fat or animal fats with 15 to 45 parts by weight of alkylbenzenesulfonic acid with an average alkyl length of C1. and C2. and 8 to 55 parts by weight of oxidized paraffin with an acid number of 60 to 180 mg KOH/g, the melting point of the starting paraffin being between 48 and 62 C.

Description

The invention relates to a corrosion inhibitor which is intended in particular for means for the temporary protection of metallic materials. These agents are used during the manufacture, transport, storage and use of metal products, mainly iron and its alloys.

Corrosion causes enormous damage worldwide. Due to the formation of corrosion products, metallic materials lose their strength and are degraded functionally and visually. To reduce or completely eliminate these negative phenomena, temporary protective agents, of which corrosion inhibitors are an important component, are widely used. By chemical reaction with the metal surface, reaction with aggressive components, the barrier effect of the formed film, corrosion inhibitors reduce the penetrating negative phenomena. Their effectiveness can be assessed by reducing the corrosion losses achieved in a standard environment according to the relevant standards. Depending on the environment, type of protection, type of aggressive substance, carrier liquid, method of use, etc., a wide range of substances such as succinic acid compounds, phosphorus, organic sulfur compounds, nitrites, benzoates, corrosive earth metal salts, fatty salts are used as corrosion inhibitors. acids and their salts, etc ... When using petroleum, water-immiscible substances, such as petrol, oils, petrolatum and waxes, the most common uses are substances based on organic nitrogen compounds such as nitriles, fatty acid amines, their aminoamides, urea, hydrazine, hexamethylenetetramine, aromatic and heterocyclic substances are described in a number of publications. The most commonly used corrosion inhibitors in oils are acylaminoamides and their cyclized imidazole-based derivatives.

Several factors must always be considered when evaluating individual inhibitors.

The most important application property is, of course, the protective effect. In the case of high-quality inhibitors, for example, a few percent addition to the oil reduces the corrosion losses of the order of magnitude compared to the use of the non-additive oil alone. The protective effect is largely related to the solubility or miscibility of the carrier liquid with the inhibitor. The prepared homogeneous solution or emulsion of the inhibitor in the carrier liquid must be stable. The formation of solid products often makes it impossible to use an inhibitor. Of course, raw material security, preparation technology and, last but not least, economic factors also play a role in industrial practice.

The above requirements are also met by products resulting from the reaction of alkylaryl sulfonic acids with higher alkylamines in combination with paraffin oxidation products and higher fatty acid monoethanolamides. However, monoethanolamides of higher fatty acids as an inhibitor component are somewhat expensive. Their preparation, which leads through the saponification of triglycerides, through the decomposition of alkaline soaps, the separation of glycerol and the refining of liberated fatty acids, requires considerable energy costs and relatively demanding technological equipment. These disadvantages are eliminated by the inhibitor according to the invention, which consists in reacting up to 40 parts by weight of the product of direct aminolysis, natural fats and 10 to 35 parts by weight of alkylamine having 12 to 22 carbon atoms in alkyl having 15 to 22 carbon atoms. 45 parts by weight of alkylbenzenesulfonic acid with an average alkyl content of 8 to 55 parts by weight of oxidized paraffin with an acid number of 60 to 180 mg KOH / g.

The melting point of the starting paraffin is between 48 and 62 ° C.

The fatty acid monoethanolamide moiety as an inhibitor component is prepared by direct reaction with natural fat. Due to the significantly higher molecular weight of fatty acids per 1 mole of glycerin, 3 moles of fatty acids are bound, the amineolysis product contains about 10% glycerol. However, depending on the molar ratio of monoethanolamine to decomposed fat selected, the mixture may also contain a substantial base of glycerin bound in the form of a fatty acid monoglyceride (at a lower monoethanolamine: fat ratio than 3 .mu.l) or free glycerin and monoethanolamine (at a higher molar ratio). Of course, side reaction products such as ester, esteramide, fatty acid soaps with monoethanolamine, etc. are also found. For the inhibitor according to the invention, it is necessary that the decomposition product contains at least 75% of monoethanolamides.

CS 26Θ624 Bl

Oxidized paraffin is a complex mixture of fatty acids, oxyacids, hydroxy acids, aldehydes, esters, esters and non-oxidized residues. Oe characterized mainly by the melting point of the starting paraffin with an acid number. Oxiparaffin with an acid number of 60 to 180 mg KOH / g is required for the inhibitor according to the invention. The starting paraffin has a melting point between 4Θ and 62 ° C.

Alkylbenzenesulfonic acid suitable for the inhibitor according to the invention is a technical product with the usual name dodecylbenzenesulfonic acid. Depending on the origin and method of preparation, alkyl consists of 10 to 14 carbon atoms, the middle being between 11.5 and 12 carbon atoms. The required content of free sulfuric acid is max. 5%, content of unsulfonated content max. 3%.

□ Technical octadecylamine is preferably used as the alkylamine, which, depending on the origin of the starting acid, also contains amines with alkyl of 12 to 20 carbon atoms.

In the following examples, the effect of the inhibitor is compared with a conventional oleyldiethylenediaminamide inhibitor in a mixture with a cyclized imidazoline derivative as formed by the condensation of oleic acid with diethylenetriamine. The reference inhibitor is referred to in the examples as a "commercial inhibitor.

Example 1 10 parts by weight of technical grade octadecylamine, which on average contained 90% octadecylamine,% dodecylamine, 2% tetradecylamine, 4% hexadecylamine and 2% eicosylamine, were melted together with parts by weight of a mixture obtained by aminolysis of rapeseed oil with monoethanolamine and 1 mol triglyceride ratio. : 3 moles of ethanolamine. Parts of alkylbenzenesulfonic acid were added. Alkyl contained an average of 11.7 carbon atoms. The increase in temperature caused by the exothermic course of the reaction was compensated by cooling and interruption of the sulfonic acid dosing. After the addition of the sulfoic acid was complete, a further 15 parts by weight of oxiparaffin with an acid number of 90 mg KOH / g were added. The starting paraffin had a melting point of ° C. The mixture was stirred for another 0.5 h and then cooled.

The application properties were verified in the form of a 3% solution of the inhibitor in regular white spirit. Such a preparation is commonly used in mechanical engineering for the removal of impurities and in the inter-operational protection of steel and cast iron products. The achieved anticorrosion protection was evaluated on iron sheet samples. After applying the solution to corrosion samples of steel class. 11 and drying, the test sheets were exposed to 40 ° C in a 100% humidity chamber. II unprotected sheets, corrosion products were formed within 24 hours, which covered practically the entire area of the sample. Samples protected with a 3% inhibitor solution were corroded after 5 days, while samples protected with a commercial inhibitor were covered with corrosion products as early as 3 days.

Example 2

Following the procedure of Example 1, a corrosion inhibitor was prepared which consisted of a reaction product of 12 parts by weight of octadecylamine mixed with.

parts by weight of the mixture obtained by direct aminolysis of coconut fat with monoethanolamine in a molar ratio of 1 mol of triglyceride to 3 mol of ethanolamine. Parts of the masses of dodecylbenzenesulfonic acid were added to the melt and then mixed with parts of the masses of oxidized paraffin prepared from paraffin with a melting point of 58-60 ° C, which had an acid number of 115 mg KOH / g

The inhibitor was tested as a 6% solution in bearing oil. Steel samples class. 11 were exposed under the conditions of CSN 03 Θ2Ο5 Annex Ol at 40 ° C and 100% humidity. After 30-day exposure the samples were protected inhibitors of the invention Corrosion decreases from 8 to 10 g / ² and j samples protected etandardním inhibitor then drop to 20 g / ² ·, the preservation eamotným oil loss of 80 g / ² and decreases unprotected samples were around

CS 268624 81

120 g / m.

Example 3

Following the procedure of Example 1, a corrosion inhibitor was prepared which consisted of the reaction products of 34 parts by weight, hexadecylamine with octadecylamine 14 parts by weight, mixture obtained by direct aminolysis of rapeseed oil with monoethanolamine in 1 mol ethanolamine: 1 mol fatty parts. acid with an average number of 11.3 carbon atoms in the alkyl chain and parts by weight of oxidized paraffin, which was prepared by oxidation of paraffin with a melting point of 59 ° C so as to have a final acid number of 100 mg KOH / g.

The adjuvant inhibitor was evaluated as a 5% solution in bearing oil. After 30 days of epilation, the samples protected by the inhibitor were virtually free of corrosion. Comparative samples protected with a standard inhibitor showed corrosion in 11% of the area and the area of unprotected samples was 100% covered with corrosion products.

Example 4

Following the procedure of Example 1, a corrosion inhibitor was prepared which consisted of a reaction product of 14 parts by weight, technical octadecylamine 10 parts by weight, a mixture obtained by direct aminolysis of a mixture of beef tallow and vegetable oil with monoethanolamine.

parts by weight of alkylbenzenesulfonic acid having an average number of 12 carbon atoms in the alkyl and 54 parts by weight of oxidized paraffin with an acid number of 90 mg KOH / g, which was prepared by oxidation of paraffin with a melting point = 57 ° C.

The prepared inhibitor was evaluated according to the procedure described in Example 3. After 30 days of exposure, 6% of the protected area was covered with corrosion products, compared to 11% for samples protected with an equally concentrated solution of standard inhibitor or standard inhibitor. 100% of the area covered by corrosion products of oil-protected samples and unprotected samples. ·

Claims (3)

OBJECT OF THE INVENTION Corrosion inhibitor intended in particular for means of temporary protection of metallic materials, characterized in that it consists of a reaction product of 10 to 35 parts by weight of an alkylamine having 12 to 22 carbon atoms and 5 to 40 parts by weight of the product of direct aminolysis of natural fats such as sunflower oil, rapeseed oil, palm kernel oil, coconut fat or animal fats with 15 to 45 parts by weight of alkylbenzenesulfonic acid with an average alkyl length and C 1-4 alkyl 8 to 55 parts by weight of oxidized paraffin with an acid number of 60 to 180 mg KOH / g, the melting point of the starting paraffin is between 48 and 62 ° C.