RU2197563C1 - Corrosion inhibitor of ferrous metals - Google Patents

Abstract

FIELD: chemistry. SUBSTANCE: invention can be utilized to produce oil-soluble corrosion inhibitors of ferrous metals of sulfonate type which are used in the capacity of additives to motor oils, to lubricating-cooling fluids and as anticorrosion and rust-preventing treatment materials. Corrosion inhibitor of ferrous metals includes magnesium oxide or hydroxide, fat-soluble organic reagent-natural fat, alkylbenzosulfonic acid, organic solvent and alkanolamine with following proportion of components, per cent by mass: magnesium oxide or hydroxide 0.21-3.70; natural fat 3.65-72.03; alkynbenzosulfonic acid 3.43-74.10, alkanolamine 1.10-27.49, organic solvent being the balance. Vegetable or animal fat is used in the capacity of natural fat in composition of corrosion inhibitor of ferrous metals. EFFECT: enhanced protective potential while exposed to atmospheric effects. 2 cl, 3 tbl

Description

 The invention relates to chemistry and can be used in the production of oil-soluble sulfonate type corrosion inhibitors of ferrous metals, which are used as additives in motor oils, cutting fluids, and also as anticorrosive and conservation materials.

 Corrosion inhibitors of ferrous metals based on magnesium-containing complexes are known (see US patents 4094801, IPC С 10 М 001/44, publ. 06/13/1978; 4253976, IPC С 10 М 001/44, publ. 03.03.1981; 4260500, IPC С 10 M 001/44, publ. 04/07/1981; 4322478, IPC B 32 V 009/00, publ. 30.03.1982). These corrosion inhibitors of ferrous metals contain magnesium oxide or hydroxide, sulfonic acid, phosphoric acid, a mixture of them with an organic acid, or a mixture of their esters or their salts, water and an organic solvent.

 The disadvantage of these corrosion inhibitors of ferrous metals is the low protective ability under atmospheric exposure.

 The closest in technical essence and the achieved result to the claimed is a corrosion inhibitor of ferrous metals based on magnesia oxide carboxylate complexes (see US patent 4322479, IPC B 35 V 009/00, publ. 30.03.82). This ferrous metal corrosion inhibitor contains magnesium oxide or hydroxide, a fat-soluble organic reagent, including alkylbenzenesulfonic acid or a mixture consisting predominantly of this acid with the addition of sulfonic acid or phosphoric acid, or their esters, or their alkali or alkaline earth metal salts, an organic solvent and water.

The disadvantage of this corrosion inhibitor of ferrous metals is the low protective ability when exposed to the atmosphere. So, when using this corrosion inhibitor of ferrous metals under atmospheric exposure, its protective ability is characterized by the following indicators:
- the time until the first signs of corrosion with increased values of relative humidity and air temperature (without condensation) is 200 hours,
- the time until the first signs of corrosion with constant immersion in the electrolyte is 36 hours,
- the area of the affected surface when exposed to salt fog for 48 hours is 50%.

 The technical problem solved by the claimed corrosion inhibitor of ferrous metals is to increase the protective ability under atmospheric conditions.

The stated technical problem is solved due to the fact that the corrosion inhibitor of ferrous metals, including magnesium oxide or hydroxide, a fat-soluble organic reagent, alkyl benzosulfonic acid and an organic solvent, according to the invention contains fat as a fat-soluble organic reagent and additionally contains alkanolamine in the following ratio, wt. %:
Magnesium oxide or hydroxide - 0.21-3.70
Natural fat - 3.65-72.03
Alkylbenzenesulfonic acid - 3.43-74.10
Alkanolamine - 1.10-27.49
Organic Solvent - Else
moreover, as a natural fat contains vegetable or animal fat.

 The content of these components in the composition of the corrosion inhibitor of ferrous metals provides increased protective ability during atmospheric exposure by obtaining a combined corrosion inhibitor of ferrous metals, namely, combining the production of metal sulfonate with the synthesis of mono- and diglycerides and esters of fatty acids and alkanolamine.

Wherein
- as a result of the interaction of magnesium oxide or hydroxide with alkylbenzenesulfonic acid, the formation of magnesium alkylbenzenesulfonate - a component of a combined corrosion inhibitor of ferrous metals,
- as a result of the interaction of natural fat and alkanolamine, the transesterification reaction occurs with the formation of a mixture of mono- and diglycerides of fatty acids, a fatty acid ester and alkanolamine - components of a combined corrosion inhibitor of ferrous metals,
- as a result of polymerization by unsaturated bonds of mono- and diglycerides of fatty acids, fatty acid ester and alkanolamine, the protective ability of the corrosion inhibitor of ferrous metals is enhanced,
- as a result of complexation of magnesium alkylbenzenesulfonate with monoglycerides, diglycerides, fatty acid ester and alkanolamine, the formation of donor-acceptor bonds Me-O, Me-N occurs, and the protective ability of the corrosion inhibitor of ferrous metals is enhanced.

 The content of these components in the composition of the initial mixture provides an increase in the protective ability of the finished product under atmospheric effects due to the occurrence of a synergistic effect when it is received, associated with the formation of a combined corrosion inhibitor of ferrous metals and the effect of polymerization and complexation processes on its properties.

 For the implementation of the claimed invention, the following compositions of the corrosion inhibitor of ferrous metals were prepared, differing from each other in the content of components, namely: composition 1 - with the optimal ratio of components using magnesium oxide and vegetable oil as fat, composition 2 - with the optimal ratio of components using hydroxide magnesium and vegetable oil as fat, compositions 3 and 4 - at the boundary values of the components using magnesium oxide and vegetable oil as fat, you are 5 and 6 - at the boundary values of the components using magnesium hydroxide and vegetable oil as fat, composition 7 - at the optimal ratio of components using magnesium oxide and pork fat as fat, composition 8 - at the optimal ratio of components using magnesium hydroxide and pork fat as fat, compositions 9 and 10 - at the boundary values of the components using magnesium oxide and pork fat as fat, compositions 11 and 12 - at the boundary values of the components using hydroxide and magnesium and pork fat as fat. In compositions 1-12, triethanolamine "h" was used as alkanolamine (see TU 6-09-14-1553-78). In composition 13, the technical product Triethanolamine Technical (see TU-6-02-916-79) was used as alkanolamine with an optimal ratio of components using magnesium oxide and vegetable oil as fat.

 For the preparation of compositions 1–13, we used alkylbenzenesulfonic acid produced by KINEF, grade A (average molecular weight 320), in the city of Kirishi, Leningrad Region. For compositions 1, 2, 4, 6, 7, 8, 10, 12, 13, the organic solvent used is alkylbenzene, which is part of the original alkylbenzenesulfonic acid. For compositions 3, 5, 9, 11, a mixture of alkylbenzene, which is part of the initial alkylbenzenesulfonic acid and industrial oil I-20A according to GOST 20799-88, was used as an organic solvent.

To obtain a corrosion inhibitor of ferrous metals from composition 1, 100 g of alkylbenzene sulfonic acid and 300 g of vegetable oil were placed in a reactor equipped with a stirrer and a direct refrigerator, stirred and 7 g of magnesium oxide were added, with further stirring, the reaction mass was heated to 90 ^° C and the reaction was carried out in for 0.5 hours, after which 100 g of triethanolamine "h" was poured into the reactor, the temperature was raised to 180 ^° C and stirring was continued for 2 hours until a homogeneous mass was obtained and magnesium oxide was completely dissolved. Similarly received a corrosion inhibitor of ferrous metals from compositions 2-13. Mass percent and equivalent weight amounts of ingredients for the preparation of compositions 1-13 are shown in table 1.

The resulting metal corrosion inhibitor is a greasy red-brown product of various viscosities. Each composition of a metal corrosion inhibitor was tested by standard methods according to GOST 9.054-75. For each composition of the inventive corrosion inhibitor of ferrous metals, the following indicators were determined:
- the time until the first signs of corrosion appear at elevated values of relative humidity and air temperature (without condensation),
- the time until the first signs of corrosion with constant immersion in the electrolyte,
- the area of the affected surface when exposed to salt fog for 48 hours

 The known corrosion inhibitor of ferrous metals, adopted as a prototype, was modeled in accordance with the description of the invention (see US patent 4 322479, IPC B 35 V 009/00, publ. 30.03.82, example 3) with the same molecular ratio "alkylbenzenesulfonic acid : a mixture of hydrogenated fatty acids "Hydrex-440" and the molecular ratio "magnesium oxide": (alkylbenzenesulfonic acid + a mixture of hydrogenated fatty acids "Nutrex-440"). "

 The test results of the inventive metal corrosion inhibitor for compositions 1-6, as well as the corresponding parameters of the known corrosion inhibitor of ferrous metals, taken as a prototype, are shown in table 2. The test results of the inventive metal corrosion inhibitor for compositions 7-13, as well as the corresponding parameters of the known corrosion inhibitor ferrous metals, taken as a prototype, are shown in table 3.

 Analysis of the results of the tests allows us to draw the following conclusions.

 - The inventive corrosion inhibitor of ferrous metals provides the following indicators of protective ability under atmospheric effects: the time until the first signs of corrosion at elevated values of relative humidity and air temperature (without condensation) is 720 hours, the time until the first signs of corrosion occurs with constant immersion in the electrolyte is 180 h, the area of the affected surface when exposed to salt fog for 48 h is 5%, with an optimal ratio of components and using AANII triethanolamine "h" as an alkanolamine (see. Table. 2, 3 for compositions 1, 2, 7, 8). The value of the viscosity of the final product provides the possibility of its use as an inhibitor of corrosion of ferrous metals.

 - The inventive corrosion inhibitor of ferrous metals provides the following indicators of protective ability under atmospheric effects: the time until the first signs of corrosion at elevated values of relative humidity and air temperature (without condensation) is 600 - 528 hours, the time until the first signs of corrosion occurs with constant immersion in the electrolyte is 150 hours, the area of the affected surface when exposed to salt fog for 48 hours is 15%, with the maximum allowable content of silt oxide and magnesium hydroxide and alkylbenzene sulfonic acid and the minimum allowable content of natural fat and alkanolamine and the use of triethanolamine "h" as alkanolamine (see tab. 2, 3 for compositions 3, 4, 9, 10). In this case, the value of the viscosity of the final product increases, which leads to technological difficulties of its use as an inhibitor of corrosion of ferrous metals, although application is possible.

 - The inventive corrosion inhibitor of ferrous metals ensures the achievement of the following indicators of protective ability under atmospheric influence: the time until the first signs of corrosion at elevated values of relative humidity and air temperature (without condensation) is 360 - 300 hours, the time until the first signs of corrosion appear with constant immersion in the electrolyte is 100 hours, the area of the affected surface when exposed to salt fog for 48 hours is 30%, with a minimum permissible oxide content or magnesium hydroxide and alkylbenzene sulfonic acid and the maximum allowable content of natural fat and alkanolamine and the use of triethanolamine "h" as alkanolamine (see tab. 2, 3 for compositions 4, 6, 10, 12). The obtained values of the protective ability of the inventive corrosion inhibitor of ferrous metals under atmospheric exposure correspond to the lower limit of operational requirements.

 - The inventive corrosion inhibitor of ferrous metals ensures the achievement of the following indicators of protective ability under atmospheric influence: the time until the first signs of corrosion at elevated values of relative humidity and air temperature (without condensation) is 840 hours, the time until the first signs of corrosion with constant immersion in the electrolyte is 200 h, the area of the affected surface when exposed to salt fog for 48 h is less than 5%, with an optimal ratio of components to using the technical product "technical triethanolamine" as alkanolamine (see tab. 3 for composition 13). The above values of the protective ability of the inventive corrosion inhibitor of ferrous metals under atmospheric exposure correspond to the best version of the operational requirements, while the value of the viscosity of the final product provides the possibility of its use as an inhibitor of corrosion of ferrous metals.

The use of the inventive corrosion inhibitor of ferrous metals provides the following technical and economic advantages:
- increase the protective ability under atmospheric effects, namely:
- the time until the first signs of corrosion with increased values of relative humidity and air temperature (without condensation) is at least 720 hours,
- the time until the first signs of corrosion with constant immersion in the electrolyte is at least 180 hours,
- the area of the affected surface when exposed to salt fog for 48 hours is 5%,
- the exclusion of water content in the final product,
- the exclusion of volatile solvents in the final product,
- increasing the content of basic salts of magnesium in the final product,
- simplification of the method of producing a ferrous metal inhibitor by providing the possibility of carrying it out in one stage.

Claims (3)

1. A corrosion inhibitor of ferrous metals, including magnesium oxide or hydroxide, a fat-soluble organic reagent, alkyl benzosulphonic acid and an organic solvent, characterized in that it contains natural fat as a fat-soluble organic reagent and additionally contains alkanolamine in the following ratio, wt. %:
Magnesium oxide or hydroxide - 0.21-3.70
Natural fat - 3.65-72.03
Alkylbenzenesulfonic acid - 3.43-74.10
Alkanolamine - 1.10-27.49
Organic Solvent - Else.  2. The corrosion inhibitor of ferrous metals according to claim 1, characterized in that it contains vegetable fat as natural fat.  3. The corrosion inhibitor of ferrous metals according to claim 1, characterized in that it contains animal fat as natural fat.

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