MXPA99005704A - Compositions and methods for inhibition of corros - Google Patents

Abstract

Compositions for inhibiting corrosion and methods for inhibiting corrosion of metal surfaces by the action of aqueous corrosive fluids are provided. According to the invention, a corrosion inhibiting composition composed of one or more aldehyde oligomers having the general formula (See Formula) are combined with the aqueous corrosive fluid.

Description

COMPOSITIONS AND METHODS FOR THE INHIBITION OF CORROSION BACKGROUND OF THE INVENTION 1. Field of the Invention. The present invention relates to corrosion inhibiting compositions and methods for inhibiting corrosion of metal surfaces by means of aqueous corrosive fluids. 2. Description of the Prior Art Underground formations containing hydrocarbons penetrated by well boreholes are often treated with aqueous acids to stimulate the production of hydrocarbons thereof. One of these treatments known generally as "acidification" includes the introduction of an aqueous acid solution into an underground formation under pressure so that the acid solution flows through the interstices of the formation. The acid reacts with acid-soluble materials contained in the formation thus increasing the size of the interstices and increasing the permeability of the formation. Another treatment to stimulate production, known as "acidification by fracture" includes the formation of one or more fractures in the formation and the introduction of an aqueous acid solution into the fractures to bite the P1385 / 99MX fracture faces, with which channels are formed in the fracture when the fractures are closed. The acid also enlarges the interstices in the fracture faces and in the formation. While treatments for well stimulation by acidification and acidification by fracture have been carried out successfully for many years, a continuous problem that accompanies the treatments is the corrosion of metallic surfaces in pumps, tubular articles and equipment used to introduce Aqueous acid solutions inside the underground formations that are going to be treated. The expense associated with the repair or replacement of tubular articles and equipment damaged by corrosion can be very high. Corrosion of tubular articles and downhole equipment is increased by the elevated temperatures found in deep formations, and corrosion results in at least partial neutralization of the acid before reactions with acid-soluble materials in the formations. Aqueous acid solutions are also used in a variety of other industrial applications to contact and react with acid-soluble materials. In these applications, the metal surfaces are also necessarily in contact with the acid and any corrosion of the P1385 / 99MX metal surfaces is highly undesirable. In addition, other corrosive fluids such as aqueous alkaline solutions, heavy brines, petroleum streams containing acidic materials and the like are normally transported to and corrode metal surfaces in tubular articles, pumping equipment and pipes. Up to now, a variety of corrosion-inhibiting compositions and formulations in metal have been developed and used that can be added to corrosive aqueous fluids. While the compositions and formulations have achieved varying degrees of success in preventing corrosion of metal surfaces, there is a continuing need to improve corrosion inhibiting compositions in metal that are effective when combined with corrosive aqueous fluids of the types described herein. above and that provide greater and more reliable inhibition for corrosion than has hitherto been possible.

SUMMARY OF THE INVENTION The present invention provides corrosion inhibiting compositions that when added to a corrosive aqueous fluid inhibit corrosion of metal surfaces that are in contact with the fluid, also provides P1385 / 99MX aqueous acid compositions that have inhibited the metallic corrosion capacity, as well as methods for using the compositions, compositions that meet the needs described in the above and overcome the deficiencies of the prior art. The compositions and methods of the present invention are based on the discovery that certain aldehyde oligomers formed by the condensation reaction of benzaldehyde and acetaldehyde provide an unexpectedly increased corrosion inhibition when added to corrosive aqueous fluids as compared to inhibitory compositions of corrosion of the prior art including aldehydes. In a surprising way, the aldehyde oligomers of this invention can be used directly in corrosive aqueous fluids without the use of a dispersing surfactant or a mutual solvent. However, in preferred corrosion inhibiting compositions of this invention, a dispersing surfactant or a mutual solvent or both is included in the compositions. A composition for inhibiting corrosion of metal surfaces when added to a corrosive aqueous fluid of this invention is basically composed of one or more aldehyde oligomers and derivatives thereof having the general formula P1385 / 99MX R, R, R.

R, X n wherein: R x is a phenyl or phenyl group substituted with one or more of the methyl, hydroxyl, methoxy or other substituent groups that do not have an adverse effect. R2 and R3 are individually hydrogen, a saturated or unsaturated aliphatic group having from 1 to about 12 carbon atoms, an aryl group or other substituent which has no adverse effect, R4 is hydrogen, - (NH-CH2-CH2- ) m-NH-CH2CH2NH2 wherein m is 0 or an integer in the range of from 1 to 5, a tris (2-aminoethyl) amine group or another substituent that does not have an adverse effect, n is an integer in the range of from 2 to 7, and X is oxygen, NH or another N- substituent that does not have an adverse effect. As mentioned, the composition for corrosion inhibition described may include a dispersing surfactant or a mutual solvent, or both, and in addition, one or more quaternary ammonium compounds, one or more activators to inhibit corrosion and other commonly used components. in formulations to inhibit corrosion. Aqueous acid compositions to inhibit P1385 / 99MX metal corrosion are also provided by this invention which are composed of water, an acid selected from the group consisting of inorganic acids, organic acids and mixtures thereof and at least one aldehyde oligomer of the type described in the foregoing. In accordance with the methods of this invention, corrosion of metal surfaces by a corrosive aqueous fluid is inhibited by combining a corrosion inhibiting composition that includes one or more of the aldehyde oligomers described above with it. It is therefore a general object of the present invention to provide improved compositions and methods for inhibiting corrosion. Other additional objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon reading the description of the following preferred embodiments.

DESCRIPTION OF THE PREFERRED MODALITIES The present invention provides improved corrosion inhibiting compositions which, when combined with a corrosive aqueous fluid, inhibit corrosion of metal surfaces which are in contact in this manner, acid compositions.

P1385 / 99MX improved aqueous to inhibit corrosion and improved methods to inhibit corrosion of metal surfaces by a corrosive aqueous fluid using the compositions. The corrosion inhibiting compositions of the present invention are basically composed of one or more aldehyde oligomers formed by the condensation reaction between the benzaldehyde and the acetaldehyde. It has been found that these oligomers provide the metal surfaces with surprisingly improved protection from corrosion by corrosive aqueous fluids when one or more of the oligomers is combined with the corrosive aqueous fluids. The aldehyde oligomers formed by means of the reaction described above which provides improved corrosion protection to metal surfaces, in accordance with the present invention, has the general formula Rj_ is a phenyl or phenyl group substituted with one or more of the methyl, hydroxyl, methoxy or other substituent groups that do not have an adverse effect. R2 and R3 are individually, hydrogen, a P1385 / 99MX saturated or unsaturated aliphatic group having from 1 to about 12 carbon atoms, an aryl group or other substituent that has no adverse effect, R4 is hydrogen, - (NH-CH2-CH2-) m-NH-CH2CH2NH2 wherein m is 0 or an integer in the range of from 1 to 5, a tris (2-aminoethyl) amine or other substituent having no adverse effect, n is an integer in the range of from 2 to 1, and X is oxygen, NH or another N- substituent that does not have an adverse effect. The substituents which do not have an adverse effect referred to above, are those substituents which do not adversely interfere with the corrosion protection provided by the aldehyde oligomers and / or which are added to the corrosion protection provided. Examples of these substituents are halides, hydroxyl groups, alkoxy groups, hydrogen, aminoalkylamine groups, imidazoline groups and the like. The most preferred aldehyde oligomers as described above are those wherein Rx is phenyl, R2, R3 and R4 are hydrogen, X is oxygen and n is 2 or 3. As mentioned, the corrosion inhibiting composition of this invention it may also include a surfactant to disperse the aldehyde in an aqueous corrosive fluid. Examples of these suitable dispersing surfactants are alkoxylated fatty acids, P1385 / 99MX Alkoxylated alkylphenol and ethoxylated alkyl amines. When a dispersion surfactant of the type described above is used in a corrosion inhibiting composition of this invention, it is generally present in the composition in an amount in the range of from about 1% to about 45% by weight of the composition. Another component that can be included in the corrosion inhibiting compositions is a solvent for the aldehyde oligomers which also dissolves in water, referred to herein as "mutual solvent". Examples of these solvents are methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, propylene glycol, dimethyl formamide, N-methyl pyrrolidone, methyl ether of propylene glycol and butyl cellosolve. When a mutual solvent of the type described above is included in a corrosion inhibiting composition of this invention, it is generally present in an amount in the range of from about 1% to about 40% by weight of the composition. In addition, the corrosion inhibiting compositions may include one or more quaternary ammonium compounds, one or more corrosion inhibitor activators, and other components commonly used in formulations to inhibit corrosion such as acetylenic alcohols, products of P1385 / 99MX Mannich condensation formed by reacting an aldehyde, a carbonyl-containing compound and a nitrogen-containing compound, unsaturated carbonyl compounds, unsaturated ether compounds, formamide, formic acid, other carbonyl sources, iodides, terpenes and aromatic hydrocarbons. The quaternary ammonium compounds which function as inhibitors for corrosion and which can be used in accordance with the present invention have the general formula: (R) 4N + X ~ wherein each R is the same or a different group selected from long chain alkyl groups, aryl groups or heterocyclic groups, and X is an anion such as a halide. The term "long chain" is used herein to mean hydrocarbon groups having in the range of from about 12 to about 20 carbon atoms. The corrosion inhibitor activators work to activate the corrosion inhibiting components such as quaternary ammonium compounds to function as corrosion inhibitors. Examples of the corrosion inhibiting activators that can be used in accordance with the present invention are cuprous iodide; cuprous chloride antimony compounds such as oxides of P138S / 99MX antimony, antimony halides, antimony tartrate, antimony citrate, alkali metal salts of antimony tartrate and antimony citrate, alkali metal salts of pyroantimonate and antimony adducts of ethylene glycol; bismuth compounds such as bismuth oxide, bismuth halides, bismuth tartrate, bismuth citrate, alkali metal salts of bismuth tartrate and bismuth citrate; iodo; iodide compounds; formic acid; and mixtures of the above activators such as, for example, a mixture of formic acid and potassium iodide. When a corrosion inhibitor activator is included in a composition of this invention, it is generally present in an amount in the range of from about 0.1% to about 5.0% by weight of the composition. As mentioned above, corrosive aqueous fluids wherein the corrosion inhibiting compositions of this invention are effective, include aqueous solutions of inorganic acids, organic acids and mixtures thereof, as well as aqueous alkaline solutions, heavy brine and hydrocarbons containing materials corrosive Metals that can be protected from corrosion by corrosion inhibiting compositions include, but are not limited to, ferrous metals such as iron and steel and non-ferrous metals such as aluminum, zinc and copper.

P1385 / 99MX In order to inhibit the corrosion of metal surfaces of the types described above, by means of a corrosive aqueous fluid, a corrosion inhibiting composition of this invention is combined with the corrosive aqueous fluid in an amount in the range of from about 0.05% to about 5% by weight of the aqueous corrosive fluid. An aqueous acid composition that inhibits the metal corrosion of this invention, for use in applications such as acidification and acidification by fracture is composed of water, an acid selected from the group consisting of inorganic acids, organic acids and mixtures thereof, and minus an aldehyde oligomer having the general formula: R, R " R, X n R x is a phenyl or phenyl group substituted with one or more of the methyl, hydroxyl, methoxy or other substituent groups which do not have an adverse effect. R2 and R3 are individually, hydrogen, a saturated or unsaturated aliphatic group having from 1 to about 12 carbon atoms, an aryl group or another substituent that has no adverse effect, R4 is hydrogen, - (NH-CH2-CH2- ) m-NH-CH2CH2NH2 in P1385 / 99MX where m is 0 or an integer in the range of from 1 to 5, a tris (2-aminoethyl) amine group or another substituent that does not have an adverse effect, n is an integer in the range of from 2 to 7 , and X is oxygen, NH or another N- substituent that does not have an adverse effect. The acid used in the aqueous acid compositions of this invention is generally present in the composition, in an amount in the range of from about 1% to about 30% by weight of water therein, the oligomer (s) being present of aldehyde in an amount in the range of from about 0.01% to about 2% by weight of the water. Aqueous acid compositions may also include a dispersion surfactant of the type described above, in an amount in the range of from about 0.001% to about 10% by weight of the water in the compositions, and / or a mutual solvent of the type described in the foregoing, present in the compositions in an amount in the range of from about 0.001% to about 30% by weight of the water. The compositions may also include one or more quaternary ammonium compounds of the type described hereinbefore in an amount in the range of from about 0.001% to about 10% in P1385 / 99MX weight of water in the compositions, and one or more corrosion inhibitor activators of the type described above, present in an amount in the range of from about 0.001% to about 8% by weight of water in the composition. Other components for inhibiting corrosion known to those skilled in the art may also be included in aqueous acid compositions. As mentioned above, the most preferred aldehyde oligomers for use in the aqueous acid compositions of this invention are those wherein R x is phenyl, R 2, R 3 and R 4 are hydrogen, X is oxygen and n is 2 or 3. The methods of this invention for inhibiting corrosion of metal surfaces by means of an aqueous corrosive fluid comprises basically combining a corrosion inhibiting composition of this invention as described above, with the aqueous corrosive fluid in the general amount of from about 0.05% to about 5%. % by weight of the aqueous corrosive fluid. The aldehyde oligomers described in the above which are useful in accordance with this invention can be synthesized according to the following procedure: 16 parts by weight of benzaldehyde are suspended in 100 parts by weight of an aqueous catalyst A of 1 to 10 percent of dough and 100 parts by weight of a B catalyst from 1 to 10 percent P138S / 99MX of mass. The catalysts A and B are of the general formulas M (OH) x and / or M (ORx) x wherein M is any metal group I or II and R1 is an acyl group having from 1 to 8 carbon atoms. The suspension is rapidly stirred and heated to a temperature ranging from about 25 ° C to about 70 ° C. From about 13.2 parts by weight to about 52.8 parts by weight of acetaldehyde are pre-dissolved in from about 20 to about 50 parts by weight of water. The resulting aqueous solution is added slowly to the benzylaldehyde suspension at a rate of approximately 0.005 to 2 milliliters per minute. After the addition is complete, the suspension is stirred for a period of up to about ten hours. The reaction product in the form of an oily bottom layer is divided between an aqueous base layer and an organic layer. The organic phase is dried and the viscous, thick, dark orange oil product is recovered. To further illustrate the compositions and methods for inhibiting corrosion, of the present invention, the following examples are provided: EXAMPLE 1 Synthesis reactions were carried out to produce aldehyde oligomers of the formula set forth in the above, wherein n was 2 or more.

P1385 / 99MX Some of the resulting aldehyde oligomers produced were added in amounts of 0.5 grams to 5 millimeters of methyl alcohol combined with a polysorbate dispersion surfactant in a volume ratio of 4: 1. Hydrochloric acid and water were then added to the oligomer solutions to yield aqueous solutions of hydrochloric acid at 15% by weight, containing the oligomers. To test the effectiveness of the oligomers in corrosion inhibition, the hydrochloric acid test solutions were heated to 150 ° F, and the N-80 carbon steel corrosion samples were immersed in the solutions for periods of approximately two hours. hours and a half while maintaining the temperatures of the solutions at 150 ° F. The corrosion rates were measured by electrochemical means by a combination of linear polarization resistance and Tafel measurements and are expressed in units of mils per year (MPY - milli-inches per year). For purposes of comparison, an α, β-unsaturated aldehyde so far used as a component in a corrosion inhibiting composition and described in U.S. Patent No. 4,734,259 issued to Frenier, et al. on March 29, 1988, ie, cinnamaldehyde, the identical procedure described above was also tested.

P1385 / 99MX The result of these tests is established in Table I below.

TABLE I CORROSION TESTS Aldehyde or Oligomer Proven Aldehyde Speed Observation Solubility Corrosion, MPY C6H5- [CH = CH] 2-CH = 0 Clear 3.8 (5.6) 1 C6H5- [CH = CH] 4-CH = 0 Nebulous 4.4 (3.4) 1 C6H5- [CH = CH] 5-CH = 0 Nebulous 11 (12) 1 C6H5- [CH = CH] 6-CH = 0 Nebulous 8.9 (10) 1 C6H5- [CH = CH] 7-CH = 0 Nebulous 9.3 (13) 1 C6H5- [CH = CH] 8-CH = 0 Nebulous 34 (35) 1 Nebulous Cinnamaldehyde 21 A second test result is shown in parentheses.

From the test results shown in Table I, it can be seen that the aldehyde oligomers used in accordance with the present invention provide improved corrosion protection as compared to the unsaturated aldehyde a, β, ie cinnamaldehyde.

EXAMPLE 2 A corrosion test was carried out using an aldehyde oligomer of this invention, synthesized with a 1: 4 ratio of benzaldehyde a P1385 / 99MX acetaldehyde. The test procedure used was the same as described in Example 1 above, except that the mutual methyl alcohol solvent and the dispersing surfactant were omitted. That is, 0.5 grams of the oligomer was mixed with water and hydrochloric acid to make an acid solution at 15% by weight, which was tested as described in Example 1. The results of this test are set forth in Table II below.

TABLE II Aldehyde or Aldehyde Speed Observation Oligomer Tested Solubility Corrosion, MPY C6H5- [CH = CH] 4-CH = 0 not dispersed In this form, the present invention is well adapted to achieve the objects and achieve the aforementioned characteristics and advantages as well as those that are inherent thereto. While numerous changes can be made by those skilled in the art, the changes are encompassed within the spirit of this invention, as defined by the appended claims.

P1385 / 99MX

Claims (23)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A corrosion inhibiting composition on metal surfaces by the action of a corrosive aqueous fluid, when the composition is added to the corrosive aqueous fluid comprising one or more aldehyde oligomers having the general formula: R, R, R] _ is a phenyl or phenyl group substituted with one or more of the methyl, hydroxyl, methoxy or other substituent groups which does not have an adverse effect. R2 and R3 are individually, hydrogen, a saturated or unsaturated aliphatic group having from 1 to about 12 carbon atoms, an aryl group or other substituent that does not have an adverse effect, R4 is hydrogen, - (NH-CH2-CH2- ) m-NH-CH2CH2NH2 wherein m is 0 or an integer in the range of from 1 to 5, a tris (2-aminoethyl) amine group or another substituent that does not have an adverse effect, n is an integer in the range of from 2 to 7, and P1385 / 99MX X is oxygen, NH or another N- substituent that does not have an adverse effect. The composition of claim 1, further comprising a surfactant for dispersing the aldehyde oligomers in the aqueous corrosive fluid. The composition of claim 2, wherein the surfactant is selected from the group consisting of alkoxylated fatty acids, alkylphenol alkoxylates and ethoxylated alkyl amines. 4. The composition of claim 1, further comprising a solvent for the aldehyde oligomers which also dissolves in water. The composition of claim 4, wherein the solvent is selected from the group consisting of methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, methyl ether of propylene glycol and butyl cellosolve. 6. The composition of claim 1, further comprising one or more quaternary ammonium compounds. The composition of claim 1, further comprising an activator for the corrosion inhibitor. The composition of claim 7, wherein the corrosion inhibitor activator is selected from the group consisting of cuprous iodide, cuprous chloride, antimony compounds, P1385 / 99MX bismuth, iodine, iodide compounds, formic acid and mixtures thereof. 9. The composition of claim 1, wherein Rx is phenyl, R2, R3 and R4 are hydrogen, X is oxygen and n is 2 or 3. 10. An aqueous acid corrosion inhibiting metal composition comprising: water; an acid selected from the group consisting of inorganic acids, organic acids and mixtures thereof present in an amount in the range of from about 1% to about 30% by weight of water in the composition; and at least one aldehyde oligomer having the general formula: R, R R. R, C - C X n R x is a phenyl or phenyl group substituted with one or more of the methyl, hydroxyl, methoxy or other substituents which does not have an adverse effect. R2 and R3 are individually, hydrogen, a saturated or unsaturated aliphatic group having from 1 to about 12 carbon atoms, an aryl group or other substituent that does not have an adverse effect, P1385 / 99 X R4 is hydrogen, - (NH-CH2-CH2-) m-NH-CH2CH2NH2 wherein m is 0 or an integer in the range of from 1 to 5, a tris (2-aminoethyl) amine or other group substituent that does not have an adverse effect, n is an integer in the range of from 2 to 7, and X is oxygen, NH or another N- substituent that does not have an adverse effect, the aldehyde oligomer is present in an amount in the range from about 0.01% to about 2% by weight of water in the composition. The composition of claim 10, further comprising a surfactant for dispersing the aldehyde oligomer in the composition, present in an amount in the range of from about 0.001% to about 10% by weight of the water in the composition. 12. The composition of claim 11, wherein the surfactant is selected from the group consisting of alkoxylated fatty acids, alkylphenol alkoxylates and ethoxylated alkyl amines. The composition of claim 10, further comprising a solvent for the aldehyde which is also dissolved in water. The composition of claim 13, wherein the solvent is selected from the group consisting of methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, methyl ether of propylene glycol and butyl cellosolve. P1385 / 99MX 15. The composition of claim 10, further comprising one or more quaternary ammonium compounds present in an amount in the range of from about 0.001% to about 10% by weight of the water in the composition. The composition of claim 10, further comprising an activator for the corrosion inhibitor present in an amount in the range of from about 0.001% to about 8% by weight of the water in the composition. The composition of claim 16, wherein the corrosion inhibitor activator is selected from the group consisting of cuprous iodide, cuprous chloride, antimony compounds, bismuth compounds, iodine, iodide compounds, formic acid and mixtures thereof. same. 18. The composition of claim 10, wherein Rx is phenyl, R2, R3 and R4 are hydrogen, X is oxygen and n is 2 or 3. 19. A method for inhibiting corrosion of metal surfaces by the effect of a fluid. aqueous corrosive comprising combining a corrosion inhibiting composition with the aqueous corrosive fluid, the corrosion inhibiting composition is composed of one or more aldehyde oligomers having the following formula: P1385 / 99MX R, R, R. R, X n R x is a phenyl or phenyl group substituted with one or more of the methyl, hydroxyl, methoxy or other substituents which does not have an adverse effect. R2 and R3 are individually, hydrogen, a saturated or unsaturated aliphatic group having from 1 to about 12 carbon atoms, an aryl group or other substituent that does not have an adverse effect, R4 is hydrogen, - (NH-CH2-CH2- ) m-NH-CH2CH2NH2 wherein m is 0 or an integer in the range of from 1 to 5, a tris (2-aminoethyl) amine group or another substituent that does not have an adverse effect, n is an integer in the range of from 2 to 7, and X is oxygen, NH or another N- substituent that does not have an adverse effect. The method of claim 19, wherein the corrosion inhibiting composition further comprises a surfactant for dispersing the aldehyde oligomers in the aqueous corrosive fluid. The method of claim 19, wherein the corrosion inhibiting composition further comprises a solvent for the aldehyde which also dissolves in water. 22. The method of claim 19, in P1385 / 99MX where the corrosion inhibiting composition further comprises one or more quaternary ammonium compounds. The method of claim 19, wherein the corrosion inhibiting composition further comprises an activator for the corrosion inhibitor. 25. The method of claim 19, wherein R x is phenyl, R 2, R 3 and R 4 are hydrogen, X is oxygen and n is 2 or 3. P1385 / 99MX