ES2625836T3 - Method to control the corrosion of a metal surface using alkyl sulfamic acids or salts thereof - Google Patents

Abstract

A method of inhibiting the corrosion of a metal surface comprising: applying at least one alkyl sulfamic acid or salt thereof to the metal surface in an amount of 1.0 to 50 ppm to inhibit corrosion of the metal surface, in the that the amount of at least one alkyl sulfamic acid or salt thereof results in a lower degree of chemical change of the metal surface than in its absence.

Description

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DESCRIPTION

Method to control the corrosion of a metal surface using alkyl sulfamic acids or salts thereof

5 Background of the invention

This application claims the benefit of the previous US provisional patent application No. 61 / 783,706, filed on March 14, 2013.

The present invention relates to the inhibition of corrosion of a metal surface using one or more anti-corrosion agents.

Corrosion has been the subject of scientific study for more than 150 years. Corrosion is a naturally occurring phenomenon that is related to the deterioration of a material or its properties due to a reaction.

15 with its surroundings. In addition to reduced longevity, corrosion also produces oxides that can further deteriorate a system through erosion, plugging and embedding. Oxides can be deposited on heat transfer surfaces, reducing efficiency and increasing energy costs. Common sources of corrosion include dissolved oxygen, bacteria, electrolysis (leakage current), differential metal (dielectric) and differential cells. Flow, temperature and pressure can affect the corrosion rate.

Corrosion inhibitors are used in oil and gas exploration and production, oil refining, chemical manufacturing, heavy compound manufacturing, water treatment and product additive industries. Since products and manufacturing processes have become more complex and the consequences of corrosion are more expensive, more attention is being paid to the control and prevention of

25 corrosion Therefore, there is still a need to identify more effective corrosion inhibitors that minimize financial and environmental costs with better toxicological profiles.

Summary of the invention

A feature of the present invention is to inhibit the corrosion of a metal surface.

Another feature of the present invention is to provide methods of using an anti-corrosion agent that has low toxicity and / or high efficiency to prevent or minimize corrosion of metal surfaces.

The methods of corrosion inhibition of metal surfaces located in a variety of different systems and environments are also features of the present invention.

In order to achieve these and other advantages and in accordance with the purposes of the present invention, as performed and described extensively herein, the present invention provides a method of inhibiting corrosion of a metal surface that includes the application of less an alkyl sulfamic acid or salt thereof to the metal surface in an amount of 1.0 to 50 ppm to inhibit corrosion of the metal surface. At least one alkyl sulfamic acid or salt thereof can be applied in any suitable manner to the metal surface, for example, the application may include one or more of the following: flow, coating, sponge rubbing, cleaning, spraying, painting, showering and fogging. The method may additionally include surface clamping

45 metal treated to corrosive agent / s.

The additional features and advantages of the present invention will be set forth in part in the description that follows and in part will be apparent from the description or can be learned through the practice of the present invention. The objectives and other advantages of the present invention will be realized and obtained by means of the elements and combinations indicated particularly in the description and the attached written claims.

It should be understood that both the above general description and the following detailed description are only exemplary and explanatory and are only intended to provide a further explanation of the present invention, as claimed.

55 Detailed description of the present invention

The present invention provides a method of corrosion inhibition of a metal surface that includes the application of at least one alkyl sulfamic acid or salt thereof or a solution containing the alkyl sulfamic acid or salt to the metal surface in an amount of 1 , 0 to 50 ppm to inhibit corrosion of the metal surface. Any type of corrosion can be inhibited, as characterized by cause and / or effect. For example, corrosion can include a uniform corrosion that extends uniformly across the surface, a pitting corrosion that is uneven and has smaller deep areas (pitting), a peel corrosion that moves along layers of elongated grains and / or intergranular corrosion that grows along the limits of

65 grain

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Any suitable or desirable alkylated sulfamic acid derivative, salt thereof, combinations thereof may be used in the present invention. More than one alkylated sulfamic acid derivative or salt thereof can be used. Sulfamic acid is also known as amidosulfonic acid, amidosulfuric acid, aminosulfonic acid and sulfamidic acid. Sulfamic acid is a molecular compound that has the formula H3NSO3. Sulfamates

5 may be O-substituted, N-substituted or di / trisubstituted sulfamic acid derivatives and are also considered sulfamic acids or salts thereof for the purposes of the present invention. Both the H3NSO3 and H2NSO2 (OH) tautomers are within the scope of sulfamic acids or salts thereof in the present invention. Alkylated derivatives of these sulfamic acids can be used.

The alkylated sulfamic acid derivative can therefore be an alkyl sulfamic acid or salt thereof. The alkyl group may contain any desirable number of carbons in a linear, branched and / or cyclic configuration. For example, the alkyl group may be methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, isopropyl, isobutyl, sec-butyl, tert-butyl, neopentyl and the like. The at least one sulfamic acid may have the formula R1R2NS (O) 2 (OH) and, for example, R1 and R2 are independently a hydrogen, a C415 C20 alkyl group or a cycloalkyl group and R1 and R2 are not both hydrogen and / or R1, R2, and N form a 5-8 membered heterocyclic ring that includes one or more of O, NH and CH2. The at least one alkyl sulfamic acid can have the formula R1R2NS (O) 2 (OH) and, for example, R1 and R2 can independently be a hydrogen, a C4-C20 alkyl group or a cycloalkyl group and R1 and R2 are not both hydrogen. The at least one alkyl sulfamic acid may have the formula R1R2NS (O) 2 (OH) and, for example, R1 or R2, but not both, be a C4-C20 alkyl group or a cycloalkyl group. The at least one alkyl sulfamic acid may have the formula R1R2NS (O) 2 (OH) and, for example, both R1 and R2 are a C4-C20 alkyl group or a cycloalkyl group. The at least one alkyl sulfamic acid may have the formula R1R2NS (O) 2 (OH) and, for example, R1, R2 and N form a 5-8 membered heterocyclic ring that includes one or more of O, NH and CH2. The sulfamic acid or salt thereof can be a halide derivative of a sulfamic acid. Examples of sulfamic acids and salts thereof that may be rented (if not already used) used in

The method of the present invention includes those described in US Pat. Nos. 7,576,041; 7,470,652; 7,345,202; 6,983,614; 6,824,668; 6,380,182; 6,110,387; 6,103,131; 5,478,461; 5,431,839; 4,386,060; 4,327,034; 4,049,709; 3,223,704; and 3,536,759. The salts include, but are not limited to, alkali metal and quaternary ammonium salts. Methods for the preparation of various sulfamic acids or salts thereof are described in Nickless, Inorganic Sulfur Chemistry, Elsevier Publishing Company, New York; 611-614 (1968).

The alkyl sulfamic acid or salt thereof may itself be applied to a metal surface or applied as part of a fluid that may optionally contain one or more additional components, for example, an additional anti-corrosion agent and / or a biocide. When combined with one or more additional anti-corrosion agents, the resulting corrosion inhibition may be subadditive, additive or superaditive (synergistic). The fluid may include a liquid, a vapor (gas) or a combination thereof. The fluid may include H2O, NH3 and / or an alcohol. The fluid can be aqueous, non-aqueous or both. The fluid may include an acid or a base in addition to the alkyl sulfamic acid.

or get out of it. The fluid may include a saline solution of at least one salt independent of an alkyl sulfamic acid salt.

The fluid containing the alkyl sulfamic acid or salt thereof can be cooled or heated or used at room temperature or other temperatures above or below 20 ° C. The pH of the fluid can be neutral or from about 0.0 to about 14, from about 2.0 to about 12, from about 4.0 to about 10 or from about 6.0 to about 8.0.

The concentration of the at least one alkyl sulfamic acid or salt thereof can be adjusted according to the particular metal surface (s) being treated and the parameters of the system in which it is used. The concentration of at least one alkyl sulfamic acid or salt thereof in a fluid system may be 1.0 ppm to 50 ppm, or 1.0 ppm to approximately 25 ppm, or 1.0 ppm to approximately 15 ppm. , or from 1.0 ppm to about 10 ppm or from 1.0 ppm to about 5 ppm. The alkyl sulfamic acid or salt thereof can be prepared as a stock solution of about 0.01% by weight to about 100% by weight, from about 0.1% by weight to about 95% by weight, from about 1.0% by weight to about 80% by weight, from about 5.0% by weight to about 75% by weight, from about 10% by weight to about 60% by weight, from about 15% by weight to about 50% by weight, from about 25% by weight to about 40% by weight of

Alkyl sulfamic acid or salt thereof based on the total weight of the stock solution. The alkyl sulfamic acid or salt thereof can be used in the methods of the invention as a solid, liquid and / or gaseous formulation. The methods according to the invention can be part of a global water treatment regime. Alkyl sulfamic acid

or salt thereof can be used with other water treatment chemicals, such as biocides (e.g., algicides, fungicides, bactericides, molluscicides, oxidants, etc.), stain removers, clarifiers, flocculants, coagulants or other chemicals commonly used in Water treatment

Depending on its use, a composition containing alkyl sulfamic acid or salt thereof according to the present invention can be prepared in various ways known in the art. For example, the composition can be prepared in liquid form as a solution, dispersion, emulsion, suspension or paste; a dispersion, suspension or paste in a non-solvent; or as a solution by dissolving the alkyl sulfamic acid or salt thereof in a solvent or combination of solvents. Suitable solvents include, but are not limited to,

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acetone, glycols, alcohols, ethers, water or other water dispersible solvents. The composition can be prepared as a liquid concentrate for dilution before its intended use. Common additives such as surfactants, emulsifiers, dispersants and the like can be used, as is known in the art, to increase the solubility of the alkyl sulfamic acid or its salt as well as other components in a composition or

5 liquid system, such as an aqueous system or composition. The composition of the invention can be solubilized by simple stirring.

A composition of the present invention can be prepared in solid form. For example, the alkyl sulfamic acid or salt thereof can be formulated as a powder or tablet using the means known in the art. The tablets may contain a variety of excipients known in the art of tablet manufacturing such as dyes or other coloring agents. Other components known in the art such as fillers, binders, emollients, lubricants or non-sticks may be included. These components may be included to improve the properties of the tablets and / or the tabletting process.

The alkyl sulfamic acid, the salt thereof and / or composition including the same can be applied directly or indirectly to a metal surface using any suitable technique, for example, flow, coating, sponge rubbing, cleaning, spraying, can be used. painting, showering and / or fogging the at least one alkyl sulfamic acid or salt thereof to the metal surface. The term "application" may include the flow of a fluid containing the at least one alkyl sulfamic acid or salt thereof on the metal surface. The method may comprise the formation of a protective film on the metal surface that includes the at least one alkyl sulfamic acid or salt thereof.

Corrosion of any suitable metal surface can be inhibited using the methods of the invention. Any metal, combinations of metals or alloys can be protected. Even surfaces containing smaller amounts or trace amounts of one or more metals can be protected. The metal can be any metal susceptible to corrosion including industrial metals. Examples of metal surfaces include those containing one or more of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, platinum, gold, mercury, niobium, iridium, molybdenum, technetium , ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, aluminum, indian, germanium, gallium, antimony, tin, lead, bismuth, cerium, praseodymium, neodymium, promised, samarium, europium, gadolinium , terbium, dysprosium, holmium, erbium, tulium and / or ytterbium and / or alloys of one or more of these metals. Alloy metals such as stainless steel, steel, mild steel, bronze, brass and the like are additional examples of metals. The metal surface may be a ferrous or non-ferrous surface. The surface can have any shape and / or dimension. The metal surface can be continuous or discontinuous. The metal can be included in one or more non-metallic media such as a plastic, a

35 rubber, a glass, a ceramic, a compound or the like. The metal can be electroplated. The metal can be galvanized. A constant or variable electric current and / or magnetic field can be applied to the metal surface. The metal surface can be heated or cooled.

The method of the invention may further include contacting the metal surface with at least one corrosive agent for which protection is sought. The application of the alkyl sulfamic acid, salt thereof and / or one or more anti-corrosion agents can be carried out before, during and / or after the contacting of the metal surface with the at least one corrosive agent. The metal surface can be part of a closed fluid system

or an open fluid system or both. Examples of systems that can be treated include, but are not limited to, cooling systems, heating systems, cooling towers, boilers, radiators, piping

45 steam, oil transport machinery and pipelines, oil production machinery and pipelines, paper and pulp machinery, running and drinking water treatment plants, plumbing, sewers, sewage treatment plants and other industrial uses that enter in contact with corrosive agents.

The invention results in a lower degree of chemical change of the metal surface in the presence of an anti-corrosion inhibitor than in its absence. Corrosion inhibition can be a partial inhibition or a complete inhibition. The chemical change can be measured, for example, by measuring a change in weight of the metal surface and / or by measuring the concentration of metal, ions thereof or salts thereof originating from the metal surface in fluid flowing beyond the metal surface. This weight loss, for example, of a corrosion test sample after exposure to a corrosive environment can

55 expressed as one thousand (thousandths of an inch) per year of penetration (MPY). 1 MPY is equal to 0.0254 mm / y, which is equal to 25.4 μm / y. The corrosion rate can be calculated with the assumption of uniform corrosion over the entire surface of the test sample. MPY can be calculated by multiplying the weight loss in grams by 22,300 and then by dividing by the product of the test sample area (square inch), the metal density of the test sample (g / cm3) and the time exposure in a corrosive environment (days). The corrosion rate from metal loss can also be calculated as mm / a = 87.6 x (W / DAT) with W (weight loss in milligrams), D (metal density in g / cm3), A ( sample area in cm2) and T (exposure time of the metal sample in hours).

Corrosion of metal can occur through electrochemical reactions at the interface between a metal and a

65 electrolyte solution. A thin film of moisture on a metal surface forms the electrolyte for atmospheric corrosion. Corrosion usually occurs at a certain rate by balancing the opposite electrochemical, anodic (metal oxidation) and cathodic (reducing a kind of solution) reactions. These reactions can occur on a metal or two or more different metals that are in electrical communication. The corrosion current can be used to generate a corrosion rate assuming an electrolytic dissolution reaction involving a chemical species. Uniform corrosion by a surface

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5 metallic allows the calculation of the corrosion rate in distance units per year. For an alloy that undergoes a uniform solution, the equivalent weight is a weighted average of the equivalent weights of the alloy components. If the solution is not uniform, corrosion products can be used to calculate the equivalent weight.

10 A weight loss can become a corrosion rate with knowledge of the density and sample area of a sample. ASTM G 102, Method for Calculation of Corrosion Rates and Information Related to Electrochemical Measurements can be used. A Foucault current instrument and a probe can be used for corrosion measurement by monitoring a conductivity curve and an impedance plane and by using one or more techniques such as single layer corrosion detection, detection

Two-layer corrosion, a limited penetration method, a dual frequency method and / or a variable frequency method.

The following examples are intended to illustrate, without limitation, the present invention.

20 Examples

Example 1

Copper metal test samples with a surface area of 3.38 inches2 (21.8 cm2) were installed in a

25 laboratory-scale liquid recirculation circuit equipped with a tank capable of holding approximately 11 l of total volume. The apparatus was designed to retain the metallic test samples in the flow of liquid flow at a chosen flow rate and temperature for a chosen period of time. After exposure for a suitable period of time, the weight loss of the metallic sample resulting from corrosion was used to calculate the corrosion rate. The exact conditions of the tests are broken down into

30 Tables 1-3. For the tests shown in the three tables, the temperature was 35 ° C, the linear velocity was 7 gallons per minute (26.5 l / min, that is, 3 feet / s or about 1 m / s) and the treatment mass It was 10 l. Synthetic water having 1,170 ppm of NaCl and 505 ppm of NaHCO3 was used, at pH 8.

In order to evaluate the performance of the corrosion inhibitor of the yellow metal, data on the rate of

35 corrosion for the test material (hexyl sulfamic acid) and a known industrial corrosion inhibitor (tolyltriazole) (identified as “TTA” in the Tables) as a control and in some cases untreated systems (blank), using samples of Brine copper test of sodium chloride-sodium bicarbonate at an initial pH of 8.8. This aqueous matrix was designed to mimic the pH, alkalinity and total dissolved solids that could be found in secondary treated municipal wastewater after four concentration cycles. He

The dosage range of the inhibitor from 5 ppm to 10 ppm was selected because this is an effective dosage range for the protection of copper with tolyltriazole.

After exposure to the corrosive environment defined by the test parameters, the corrosion test samples were cleaned with an acid solution that is capable of removing various chemical and biological deposits and 45 films that could have formed on the surface of the sample. test during exposure to the test environment. The change in weight (and the corresponding corrosion rate) determined before a test sample has been chemically cleaned helps the researcher determine the general information of the material removal and / or deposition process. The corrosion rate obtained after cleaning is considered the true corrosion rate for the system under evaluation. Comparative data of corrosion inhibitors

50 known and / or untreated systems collected at the time of evaluation of the subject inhibitor are advantageous due to the variability in experimental factors that are otherwise not easily controlled between different experiments. The MPY (thousandths of an inch per year) and µm / y of corrosion were determined in the tables.

The data presented in Tables 1-3 show that hexyl sulfamic acid has inhibitor properties of

55 corrosion resulting in copper corrosion rates much lower than those obtained in untreated systems. The data also shows that the corrosion inhibition performance of hexyl sulfamic acid copper is similar to that obtained for tolyltriazole. The data also shows that the yield of hexyl sulfamic acid as a corrosion inhibitor of copper has an inverse relationship with the concentration of the inhibitor under the given test conditions, which is similar to the yield trend obtained with tolyltriazole. Said of

60 otherwise, lower dosages, levels of treatment, were more effective in controlling corrosion than higher dosages.

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TABLE 1

Treatment

Test sample Inhibitor dosage in ppm pH Weight gain / loss in grams MPY μm / a Time hours

5 ppm of active TTA (before cleaning)

Copper, CDA110 5 8.8 0.0009 0.025 0.635 649

5 ppm of active TTA (after cleaning)

Copper, CDA110 5 8.8 0.0043 0.118 3.00 649

5 ppm hexyl sulfamic acid (before cleaning)

Copper, CDA110 5 8.8 0.0009 0.025 0.635 649

5 ppm hexyl sulfamic acid (after cleaning)

Copper, CDA110 5 8.8 0.0043 0.118 3.00 649

10 ppm hexyl sulfamic acid (after cleaning)

Copper, CDA110 10 8.8 0.0068 0.186 4.72 649

10 ppm hexyl sulfamic acid (after cleaning)

Copper, CDA110 10 8.8 0.0214 0.586 14.9 649

TABLE 2

Treatment

Test sample Dosage of the inhibitor in ppm pH Gain / loss of weight in grams MPY μm / a Time hours

White (before cleaning)

Copper, CDA110 0 8.8 0.0086 0.097 2.46 1575

White (after cleaning)

Copper, CDA110 0 8.8 0.0188 0.212 5.38 1575

5 ppm of active TTA (before cleaning)

Copper, CDA110 5 8.8 0.0022 0.025 0.635 1575

5 ppm of active TTA (after cleaning)

Copper, CDA110 5 8.8 0.0056 0.063 1.60 1575

10 ppm hexyl sulfamic acid (before cleaning)

Copper, CDA110 10 8.8 0.0044 0.050 1.27 1575

10 ppm hexyl sulfamic acid (after cleaning)

Copper, CDA110 10 8.8 0.0111 0.125 3.18 1575

TABLE 3

Treatment

Test sample Inhibitor dosage in ppm pH Weight gain / loss in grams MPY μm / a Time hours

5 ppm hexyl sulfamic acid (before cleaning)

Copper, CDA110 5 8.8 0.0018 0.174 4.42 184

5 ppm hexyl sulfamic acid (after cleaning)

Copper, CDA110 5 8.8 0.0055 0.531 13.49 184

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Treatment

Test sample Inhibitor dosage in ppm pH Weight gain / loss in grams MPY μm / a Time hours

7.5 ppm hexyl sulfamic acid (before cleaning)

Copper, CDA110 7.5 8.8 0.0036 0,348 8.84 184

7.5 ppm hexyl sulfamic acid (after cleaning)

Copper, CDA110 7.5 8.8 0.0089 0.860 21.84 184

10 ppm hexyl sulfamic acid (before cleaning)

Copper, CDA110 10 8.8 0.0033 0.319 8.10 184

10 ppm hexyl sulfamic acid (after cleaning)

Copper, CDA110 10 8.8 0.0097 0.937 23.80 184

Claims (11)

image 1 1. A method of inhibiting corrosion of a metal surface comprising: 5 apply at least one alkyl sulfamic acid or salt thereof to the metal surface in an amount of 1.0 to 50 ppm to inhibit corrosion of the metal surface, in which the amount of the at least one alkyl sulfamic acid or salt of the It results in a lower degree of chemical change of the metal surface than in its absence. The method of claim 1, wherein the at least one alkyl sulfamic acid has the formula R1R2NS (O) 2 (OH) and R1 and R2 are independently a hydrogen, an alkyl group or a cycloalkyl group, in the that the alkyl group is pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl or neopentyl and R1 and R2 are not both hydrogen. 3. The method of claim 2, wherein R1 or R2, but not both, is an alkyl group or a cycloalkyl group, wherein the alkyl group is pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl or neopentyl. 4. The method of claim 2, wherein both R1 and R2 are an alkyl group or cycloalkyl group, wherein the alkyl group is pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl or neopentyl.

The method of claim 1, wherein the alkyl sulfamic acid or salt thereof is present in a fluid applied to the metal surface.

6. The method of claim 5, wherein the fluid comprises at least one of H2O, NH3 and an alcohol.

The method of claim 5, wherein the fluid comprises an acid or a base in addition to the alkyl sulfamic acid or salt thereof.

8. The method of claim 5, wherein the fluid comprises a saline solution of at least one salt independent of an alkyl sulfamic acid salt. 30 9. The method of claim 1, wherein the application comprises one or more of the flow, coating, sponge rubbing, cleaning, spraying, painting, showering and misting of the at least one alkyl sulfamic acid or salt thereof. The method of claim 1, wherein the application comprises the flow of a fluid comprising the at least one alkyl sulfamic acid or salt thereof on the metal surface. 11. The method of claim 1, wherein the metal surface is a non-ferrous surface and preferably comprises copper or an alloy containing copper. 40 12. The method of claim 1, further comprising bringing the metal surface into contact with at least one corrosive agent.

13.

 The method of claim 1, wherein the metal surface is part of a closed fluid system. Four. Five

14. The method of claim 1, wherein the application forms a protective film on the metal surface that includes the at least one alkyl sulfamic acid or salt thereof.

fifteen.

The method of claim 1, wherein the at least one alkyl sulfamic acid or salt thereof is applied to the metal surface in an amount of 1.0 to 10 ppm.

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