CA2249171A1 - Method and composition for inhibiting corrosion - Google Patents

Abstract

A method is provided for inhibiting corrosion of metal surfaces, especially at high temperatures. The metal surface is contacted with an aminoamide of the formula or salts thereof or mixtures thereof. Compositions containing the aminoamides are provided as well as aminoamides per se.

Description

, A CA 02249171 1998-09-30 AND CoMposITIoN FOR INXIBITING CORROSION

The invention provides a method for inhibi~ing corrosion on metal surfaces and is characterized by the use of specific aminoamides as corrosion inhibitors. Compositions providing corrosion inhibition are provided. The method is applicable to corrosion inhibition of metal surfaces in general and is applied in geothermal wells, refineries, heat transfer fluids, lubricating fluids, lubricants, coating adhesives, fire retardants, plastics, glass and the like and is particularly applicable to prevention o~ corrosion in gas or oil wells. A special characteristic of the invention is the provision o~ corrosion inhibition under high temperature conditiPns with or without high pressure conditions.

Backqround of the Invention There is an increasing demand for corrosion inhibitor materials that can withstand high temperatures. This i8 because systems are becnr';ng more efficient, more complex, or are found in increasingly hostile environments such as high temperature and high pressure conditions.

Se~eral o* these systems require high temperature corrosion inhibition chemicals. Various drilling operations and the production of gas, petroleum, and geothermal deep, hot wells can experience temperatures above 150~C, sometimes above 290OC.
Certain refinery operations experience the need for inhibitors tlo perform at about 150~C to 350~C to control corrosion in the overhead equipment as well as 200~ to 400~C in specialized .. . ..

:, t . , CA 02249171 1998-09-30 t , cracking units and distillation towers. Heat transfer fluids used in process heating and cooling, ventilation and air-conditioning plants, and stationary engines such as gas-line tr~n~i~sion compressors require ~her~l stability up to about 350~C; these require corrosion inhibitors to ;n;~;ze corrosion and fouling. Various lubricants are now used in high temperature situations, such as in the case o~ engines and turbines using both petroleum-based as well as synthetic stocks. Numerous coatings, adhesives, thermosetting resins and fire-~retardant compositions also require high te~perature stability.
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The corrosion inhibitors of interest are film-forming materials.
These can be used at low levels and be applied in a variety of ways. These corrosion inhibitors have an oleopilic portion to serve as a barrier to oxygen, water and other corrosive entities, and a polar portion to bond with the metallic sur~aces. The polar portions tend to be amines, and the bon~;ng is between the nitrogen lone electron pair and the vacant d-orbitals in the metallic mol~cl7l ~r array. The oleophilic groups are usually fatty hydrocarbon ~-h;~; n~ between c~ and C30. Originally, fatty amines were used as corrosion inhibitors.

Many r ine~ are known to be thermally unstable at high temperature. They can decompose to yield ammonia, or other fragmented amines such as methylamine, and olefins. These olefins can react further under degradation conditions to produce insol7lble aromatics and polymers. This degradation causes the corrosion inhibition effect to decrease at high temperature.

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DE-Offenlegungsschrift 30 29 790 teaches a method for corrosion inhibiting in a high temperature and high pressure gas well. In this method a fatty amine having a high molecular weight or an N-alkyl-1,3-propane diamine in which the alkyl contains 16 to 30 carbon atoms is injected into said well and forms a protective layer on the metal equipment.

As is shown by the inventor of this application (product of Example 3 and its use) the most preferred corrosion inhibitor o~
the above publication proved insufficiently effective at a temperature o~ about 290~C. Obviously there is a significant ~ec~rosition of the corrosi~n inhibitor at such high temperatures. In a further method, a combination of one of the above mentioned ~;nP~ with a dialkylsulfide is used - see U.S.
Patent No. 4, 350, 600. Besides the limited stability of the amine, such a combination is disadvantageous because o~ the employment of an odorous and toxic compound.

According to u.S. Patent No. 3,959,158 corrosion of metal sur~aces in oil and gas wells can be inhibited at high temperature, that means, at about 149 to 288~C, by introduci~g into such wells a corrosion inhibiting composition comprising a primary fatty amine where the carbon atom is Cg to C~, a trimerized unsaturated fatty acid and an alkylarylsulfonic acid.
Amide ~ormation is discouraged. The corrosion inhibiting effectiveness is regarded as insufficient at a temperature of above 290~C, a temperature which cannot be excluded in deep wells, especially in gas wells.

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It is known that 2-substituted fatty acids, like nonylphenoxy-acetic acid and polyamines, like alkylene rl;;~m; nes or imidazolines derived therefrom, or isophorone diamine, can be used as corrosion inhibitors alone. According to U.S. Patent ~o.

3,775,320 a combinatiQn of both compounds in the form o~ a salt leads to a synergistically improved corrosion inhibiting e~fect.

In DE-Offenlegungsschrift 26 22 066, an alkyl- or alkenyl succinic acid can be used for salt formation with a polyamine.
It has been found by the inventor of the present application and other persons that inhibitors based on a 1,2- or 1,3-alkylenediamine or corresponding polyalkylene polyamines are of limited thermal stability. Although such compounds are well effective at low temperature, they ~ail at high temperature, e.g., at above 290~C.

As systems began to reguire increased thermal stability, fatty amides were used as corrosion inhibitors. These were formed from fatty acids and amines, or fatty amines with carboxylic acids.
Many o~ these materials, however, have poor solubility in hydrocarbon and aromatic solvents, making them difficult to apply.

When fatty acids were treated with some polyamines, the resulting imidazoline or tetrahydropyrimidine structures did provide good corrosion inhibition at lower temperatures. ~owever, much degra-dation was produced when the system being treated experienced high temperatures. This caused decreased per~ormance, increased , . .. . . . . .. . .... _ . ,.. .. ... .. ... ..... ,~ .. .... ........ .

, CA 02249171 1998-09-30 gunking/fouling, and in some ca~es, accelerated corrosion.
Additionally, these materials are easily subject to hydrolysis.

According to U.S. Patent No. 3,412,024 corrosion of iron or steel tubing and other materials formed ~rom ~errous metals which come into contact with corrosive sweet and sour crude oils, especially those con~Ain;ng corrosive brines, can be inhibited or ~n; ;7ed by treating said metals with a corrosion inhibiting composition contA;n;ng a salt of (i) alkylbenzene sulfonic acids and partial amides or (ii) monomeric, dimeric or trimeric higher fatty acids.
Said partial amides are aminoamides made from monomeric, dimeric or trimeric fatty acids and polyalkylene polyamines having 3 -amino groups. The preferred diethylenetriamine and dipropylene-1,2-triamine based amides are known to be easily converted to less stable imidazolines. It has been found by the inventor of this application that the thermal stability of said amides is too low ~or use as a corrosion inhibitor in oil and gas wells at high temperature, e.g., at 290~C to 340~C. A further disadvantage is the presence of a sulfur con~A;n;ng compound in the inhibitor composition.

According to ~P 04/202 396 A (Derwent Abstract 92-29558t36]WPIDS) lubricant with improved wire-drawing rate and increased life-time of dies contains a carboxylic amide type wax obtained by reacting a higher aliphatic monocarboxylic acid o~ its mixture with a polybasic acid with a diamine, e.g., isophorone ~;Am;ne~
m-xylylene diamine or a ~ Cz- to C6- alkylene diamine. As the ratio of diamines to monocarboxylic acid may be 1-2 to 2, the s _ 5 _ .

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reaction product includes aminoamides. There i5 no indication in said Japanese patent publication of any corrosion inhibiting effect nor any indication whereupon specific aminoamides are much more thermally stable than others and there~ore could be applied at high t~mr~ature. It has been found by the inventor of the prese~t application that the thermal stability of most of the mentioned aminoamides is low, except tha.~t of monoamides based on a higher fatty acid with isophorone ~i~r; ne.

A further aminoamide is disclosed in U.S. ~atent No. 5,391,826 and characterized in that it is a diamidotriamine from the reaction of glutamic acid and isophorone ~; ~m; ne ~t is disclosed in this document that the product may be used as raw material for the preparation of fuel and lubricant additives but ~ there is no further information on the preparations as such and on the effect.

Attempts have been made to use heteroatoms based on sulfur, - phosphorus, and silicon as high temperature corrosion inhibitors.
Eowever, these materials can produce new problems, such as poisoning catalysts in refinery systems, accelerated corrosion from degradation products and the creation of environmental hazards associated with discharges from the treated system (i.e., Nox, S0x, phosphate, etc.).

T~ere~ore,. materials that are.based on carbon, hydrogen, oxygen and .nitrogen are preferred candidates for high temperature corrosion inhibitors.

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:~ ' '.,' , . ' '.''''.. , r ~ , CA 02249171 1998-09-30 It is therefore a first object of this invention to provide new corrosion inhibitors based on C, H, 0 and N which maintain a substantial degree of their efficiency even at high temperature, i.e., within the range of about lSOa to about 4500C. It is a further object to provide a method for corrosion inhibition at said high temperature range with or without high pressure. The method and the compositions therefore are applicable under high temperature conditions in gas and oil wells as well as in other environments as disclosed herein.

~ummary of the Invention It has been found that when carboxylic acids, preferably fatty acids, are treated with branched or cyclic polyamines, preferably ~;~ ;nes which do not form cyclic 5- and 6-~embered rings in significant amounts, the resulting aminoamides have good thermal stability, solubility, and corrosion inhibition performance.
Specifically, these compounds are very suitable for use in dr;ll ;n~ fluids, deep-hot gas, oil, and geothermal wells, certain refinery operations, and other fields. The compounds are also useful for incorporation into heat transfer fluids, lubricating fluids, lubricants, coatings, adhesives, plastics, fire retardants and the like.

For inhibiting corrosion on metal surfaces, said aminoamide is brought into contact with said metal surfaces in an ef~ective amount in liquid phase which may be the neat corrosion inhibitor in molten form, or a solution or a dispersion o~ it.
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The corrosion inhibitor is an aminoamide of~-the general ~~ la Rl-Co-NR2-Z-NR3R~ (I) or mixtures thereo~, in which Z is a divalent aliphatic radical having a branched carbon chain or a divalent alicyclic ring system including ring systems with one or two attached alkylene groups and/or alkyl groups whereby said radicals comprise a carbon chain'with at least three carbon atoms between the attached NR2- and NR3R4-group and whereby the structural element -NRZ-Z-NR3R~ of ~ormula (I) does essentially not ~orm an imidazoline or tetrahydropyrimidine ring system.

R2, R3, and R4 are each, independent o~ the other, hydrogen, an aliphatic, alicyclic or aromatic radical, wherein aromatic radicals are less pre~erred.

Rl is a monovalent monomer or polymer radical preferably having an ~le~phiiic por~ion, comprising a saturated or ole~inic l;ne~r or branched hydrocarbon radical, an alicyclic or aromatic radical of which an aromatic radical is less pre~erred and an alkyl, alkenyl or alkadienyl radical with 3 to 30 carbon a~oms, most pre~erably ~ to 22 carbon atoms is pre~erred, or a salt thereof.
The Rl radicals may also contain one or more substituents selected ~rom the group consisting o~ carboxyl, amino and ~ydroxyl. The "alicyclic" and "aromatic" radicals also include the corresponding alkyl substituted radicals.

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t , , CA 02249171 1998-09-30 ~refer~ed Embodiment The aminoamide corrosion inhibitors themselves can be manufactured in a generally known manner. A carboxylic acid of the general formula Rl-COOH or a derivative thereof such as an ester Rl-CooR5 where Rs is a hydrocarbon radical such as alkyl and the like, an amide RlCoNR6R7 wherein R6 and R7 are hydrogen or a hydrocarbon radical such as alkyl and the li~e, an acid halide RICOX where X is a halogen, or an acid anhydride RICO2Rl, is reacted with an amine o~ the general ~ormula R2HN-Z-NR3R4, wherein Rl, R2, R3, R4 and Z have the above mentioned m~An;n~.
During the amidation, usually at a temperature of about 100~ to 300~C, pre~erably at 150~ to 250~C, within 0.5 to 20 h, the r ;no~~;t1e (I) i5 formed. In the reaction, mixtures o~
aminoamides may be formed and these may be employed as such or puri~ied to obtain a single pure compound.

The amine of formula R2HN-Z-NR3R~ is preferably a ~;~ ;ne, but one or more of the groups R2, R3 and R4 may comprise ~urther amino groups, e.g., aminoalkyl groups. Those aminoalkyl groups ~or R2, R3 or R4 which may form an ; ;~oline or tetrahydropyrimidine ring are excluded. R2, R3 and R~ are preferably hydrogen or a lower alXyl group of l to 5 carbon atoms and each may be the same or they may be different. Illustrative ar~ methyl, ethyl, n-propyl, isopropyl with methyl being preferred. ~ost pre~erred are diamines o~ the ~ormula H2N-Z-NH2.

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one particularly interesting group of amines which may be mentioned are those in which at least one of the carbon atoms beta to the amino group or groups present is quaternary.

A preferred ~~~ning for Z is a branched alkylene group wherein the chain between the amino groups to which Z is attached has at least 3 carbon atoms and said chain has at least one, preferably more than one, lower alkyl substituents, such as methyl and ethyl. It is important that Z be such that the structural element -NR2-Z-NR3R~ of formula (I) essentially does not ~orm an imidazoline or tetrahydropyrimidine ring system. Most preferred branched alkylene groups have 6 to 10 carbon atoms. Examples of diamines of the formula H2N-Z-NH2 are: 2,2-dimethyl-1,3-~;Aml n~propane; 2-methyl-1,4-~;~ ;nobutane; 2-ethyl-1,5-~;~;nopentane; 2,4,4- or 1~l~3-trimethyl-l~6-~;~m;no~ ne; 2-methyl-1,5-~;nopentane; 2-ethyl-2-butyl-1,5-~;~;nopentane.
Examples of triamines are 4-r-;n~thyl-1,8-~;~;nooctane and N-substituted di-1,3-propylenetriaminewhereinthesubstituents are such as to avoid ring formation. Others which may be mentioned are 1-t2-aminomethyl)-piperazine, 1-(2-aminomethyl)-4-amino-piperidine and 4-methyl-1,4,7-triazaheptane.

Another preferred ~ning for Z comprises a mono-, di- or tricyclic ~ive- and/or six-membered cycloaliphatic ring system.
In this ~n; ng, z preferably contains 6 to 12 carbon atoms. The ring system may comprise lower alkyl substituents, e.g., methyl, ethyl, n- or iso-propyl. One or both of the amino groups attached to Z may be linked thereto directly at a secondary or .. ,- i' , ~

r , , , ~ CA 02249171 1998-09-30 ~tertiary carbon atom of the ring system or may be l;nke~ at an alkyl substituent. ~xamples of cyclic ~;Ar;nes o~ ~ormula H2N-Z-NH2 are: 1,4-- and 1,3-~ 9 ;nocyclohexane ~The trans isomer of both, the 1,4- and 1,3-diaminocyclohexane, is pre~erred because said ;~ ?r cannot ~orm cyclics. In order to a~oid ring ~ormation o~ the cis-isomers, at least one nitrogen atom o~ the ~;~;ne should be su~ficiently substituted.]; 1,3- or 1,4-bis-(aminomethyl)cyclohexane;bis(4-aminocyclohexyl)-methane;bis(4-amino-3-methylcyclohexyl)-methane; 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (=isophorone~;~; n ~ ); 3(4), 8 ( 9 ) - bis(amino-methyl)-tricyclo~5,2,1,0i6~ ~cAne; 2(3),5(6)-bis(~;no~ethyl)-bicyclo~2,2,1 ]heptane(=~ ;no~thyl-norbornylene) ;i,8--r~;~;no-l-methyl-4-isopropyl-cyclohexane (=1, 8 - ~; ~; nomenthane) and 3-cyclohexyl-aminopropyl-amine.

Z r.ay also ~e a diva~ent aromati~ or aro~atic~ tic ra~ica~, like e.g., meta- or para-phenylene or -C6H~-(C~2)3, but usually such radicals are less pre~erred c _-~ed to said aliphatic or alicyclic radicals.

The Rl r~;c~l o~ the carboxylic acid part of the aminoamide can be linear or branched, aliphatic or cycloaliphatic, saturated or unsaturated or aromatic; aromatic is less pre~erred. Said R1 radical may also contain one or more substituents selected from the group consisting o~ carboxyl, amino and hydroxyl. Pure carboxylic acids or mixtures o~ natural or synthetic carboxylic acids can be used. A linear alkyl or alkenyl group R~ with 7 to 22 carbon atoms is most favored. In ca~e o~ a suf~iciently , , , CA 02249171 1998-09-30 oleophilic group RZ, R3 or ~, then Rt may be a short chain radical, otherwise a radical Rl with at least 4 carbon atoms is preferred;

Examples of saturated aliphatic fatty acids are: formic, acetic, propionic, butyric, valeric, caproic, haptanoic, caprylic, nonanoic, capric, undecanoic, lauric, tridecanoic, myriatic, ~pentadecanoic, palmitic, heptadecanoic, stearic, nonadecanoic, eicosanoic, heneicosanoic, docosanoic, trocosanoic, tetracosanoic, pentacosanoic, cerotic, heptacosanoic, montanic, nonacosanoic, melissia, and the like.

Examples of ethylenic aliphatic carboxylic acids are the pentenoic acids, the hexenoic acids, the octenoic acids, the nonenoic acids, the decenoic acids, the tridecenoic acids, the tetradeceneoic acids, the pentadecenoic acids, the hexadecenoic acids, the heptadecenoic acids, the octadecenoic acids, the nonadecenoic acids, the eisosenoic acids, the decosenoic acids, the tetracosenoic acids.

Examples of cyclic aliphatic acids are: naphthenic acids, hydrocarbic and chaulmoogric acids, cyclopentane carboxylic acids, cyclohexanecarboxylic acids, G~ -_horic acid, and ~encholic acid.

Examples of mixed fatty acids are those as obt~;n~hle from lard oil, coconut oil, rapeseed oil, sesame oil, tall oil, palm oil, , . .,~ , '' ,~.
',' r I ~ , . CA 02249171 1998-09-30 palm kernel oil, olive oil, corn oil, cottonseed oil, dardine oil, tallow, soya bean oil, peanut oil, castor oil, seal oils shale oils, shark oils, other fish oils, teaseed oil, partially or completely hydrogenated Ani ~1 or vegetable oils or obt~in~hle from waxes like beeswax, spermaceti, montan, Japan wax, coccerin, and carnuba wax, paraffin wax, petroleum jelly, naphthenics, and blown oil fatty acids.

It is also possibIe to use di- and polycarboxylic acids, preferably in combination with monocarboxylic acids. Examples of Al ;ph~tiC polycarboxylic acids are: oxalic, malonic, succinic~
glutaric, adipic, pimelic, suberic, azelaic, sebacic, nonadicarboxylic, decanedicarboxylic undecanedicarboxylic, tartaric, fumaric, maleic, mesoconic, citraconic, glutonic, itaconic, muconic, aconitic, and the like. Industrial polymeric, i.e., dimeric and higher ral~y acids are aiso usefui in ~his invention.

An example of a hydroxyl group-cont~;nin~ acid of the formula Rl-COOH i8 9,10--dihydroxystearic acid. Bxamples of amino group--cont~in~ng acids are 6-amino caproic acid, aspartic acid and glutamic acid.

Additionally, the ratio of fatty acid to amino functionality can be broad. The normal ratio is about one carboxylic acid group per every two amino groups in the di- or polyamine raw material.
However, other ratios are useful. For instance, the ratio can favor ~c~sc fatty acid or ~c~ss polyamine. As to a further . .

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embodiment, salts of the aminoamides can also be useful. A salt can be formed via unreacted fatty acid and the amino group of the aminoamide product. Salts can also be formed by the addition of other acids to the aminoamide product. The other acids may be fatty acids, hydroxycarboxylic acids such as hydroxyacetic acid, mineral acids, such as hydrochloric acid, polymeric acids, such as polyacrylic and polymethacrylic acids and their copolymeric polyacids with a variety of comonomers. Comonomers which can be mentioned are crotonic acid, fumaric acid, itaconic acid, maleic acid, allyl alcohol, acrylamide, methacrylamide, acrylonitrile, acrolein, methacrolein, butyl acrylate, butyl methacrylate, ethyl acrylate, ethyl methacrylate, methyl acrylate, methyl methacryl-ate, vinyl acetate, 2-hydroxyethyl acrylate, 2-hydroxyethyl meth-acrylate, styrene, butadiene, 2-carboxyethylacrylate and 2-carboxyethylmethacrylate.

In addition to the above illustrations, blends of the individual components are also useful with the scope of this invention.

In accordance with the invention corrosion inhibition is achieved on metal sur~aces, for example, mild (carbon) steel, wrought irons, cast irons, stainless steels and the like, by bringing said metal sur~ace into contact with an effective amount of the aminoamide corrosion inhibitor of the present invention. Where flowing liquid systems cont~; n; ng the corrosion inhibitor are contacted with the metal surface the effective amount is about 1 to 100 parts or higher of the aminoamide per million parts of iiquid. For static systems, e.g., batch processes, the quantity ~ CA 02249171 1998-09-30 . .

may be about 1 to 10,000 ppm. Inhibition is also possible by dipping, smearing, spraying, etc., the metal sur~ace with the pure (neat) aminoamide inhibitor or a composition contA;n;ng ~he inhibitor in, for example, an amount o~ about 1 to 99% by weight of the composition.

The invention also provides novel aminoamide products of the general ~ormula Rl-Co-NR2-z-NR3R~ These are amidation products of A~ i n~ o~ the general ~ormula R2-NH-Z-NR3R~ with Rl-COO~ or a reactive derivative thereo~ with the proviso that ~atty acid A~;~S 0~ isophorone A;A~;ne and diamidotriamines based on glutamic acid are excluded. Taking into regard the previously stated exceptions, R~, RZ, R3, R4 and Z are as de~ined above herein. Of particular note are amfnoamides based on a C~ to ~0 -and more preferably on a C~ to C~-fatty acid, which may be saturated or ha~e ole~inic groups and a branched or cyclic ~;~;ne, pre~erably one of the ~ollowing ~;~r;nes:
2,2-dimethyl-1,3-diaminopropane; 2-methyl-1,4-diaminobutane; 2-ethyl-1,5-diaminopentane; 2,2,4-or 1,1,3-trimethyl-1,6-~;~;no-hexane; Z-methyl-~,5-diaminopentane and 2-ethyl-2-butyl-1,5-~ i A ; ~opentane;trans-1,4-andtrans-1,3-diaminocyclohexane;1,3-or 1,4-bis-( ;no~~thyl)cycloheYAne; bis(4-aminocyclohexyl)-methane; bis(4-amino-3-methylcyclohexyl)-methane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane (=isophorone ~;~;ne);
3(4),8(9)-bis(aminomethyl)-tricyclo[5,2,1,026]decane;2(3),5(6)-bis(aminomethyl)-bicyclo[2,2,1]heptane(=diaminomethyl-norbornylene); and 1,8-diamino-1-methyl-4-isopropyl-cyclohexane (=1,8-~;A~;nomenthane).

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. CA 02249171 1998-09-30 In the method of this invention, the above aminoamides are used as COl osion inhibitors in the neat form, or as part of a corrosion inhibiting composition, which comprises solutions with various solvents. The solvents may be selected from: aliphatic, cycloaliphatic and aromatic solvents, ~y~thetic alkylbenzenes and hydrocarbon polymers. Examples of aliphatic solvents are:
hexanes, heptanes, octanes, nonanes, decanes, undecanes, dodecanes, tridecanes, tetradecanes, pentadecanes, hexadecanes, naphthas, gasolines, diesel, jet A fuel, kerosenes, terpentines, branched aliphatics such as isooctane, cycloaliphatics such as cyclohexane and methylcyclohexane and decahydronaphthalenes.
Blends of hydrocarbon oils, waxes, and greases are also useful in this invention.

Examples of aromatic solvents are: benzene, toluene, xylenes, mesitylene, dihydronaphthalene, tetrahydronaphthalene, cymene, cumene, ethylbenzene, propylbenzene, butylbenzene, phenylpentanes, phenylhe~n~s, phenylheptanes, phenyloctanes, phenylnonanes, phenyldecanes, phenylundecanes, phenyldodecanes, phenyltridecanes, phenyltetradecanes, phenylpentadecanes, phenylhexadecanes,phenylheptadecanes,phenyloctadecanes,andthe li~e. Blends of aromatic solvents such as heavy aromatic solvents, as well as blends o~ the above are also useful in this invention.

Examples of polymeric hydrocarbon solvents are: polybutadienes, polybutenes, polypropylenes, and blends thereof.

,~'' .'.. :, ' ', . . ' .. CA 02249171 1998-09-30 In most cases, the use~ul corrosion inhibitor is oil soluble.
However, in some cases it is advantageous that the inhibitor be water dispersible. This can be done by using the above-mentioned salt derivatives. It can also be done using cosolvents.
Examples of use~ul cosolvents are: methanol, ethanol, isopropanol, butanols, ethylhexanol, methylpropanols, carbitols, cellosolves, dimethylformamide, methylpyrrolidinone, dimethyl-sulfoxide, glyme, diglyme, ethylene glycol, diethylene glycol, and the like. Some of these materials also function as winterizing agents, e.g., ethylene glycol.

Sometimes, adjuvants are added to the inhibitor's ~ormulation, especially, surfactants. These surfactants can be anionic, cationic or nonionic in nature. Examples are: alkylsul~(on)ates, alkylcarboxylates, quaternized ammonium salts, and polyoxyethyl-enes, polyoxypropylenes, polyoxybutylenes, and various mixtures of the above.

In general, the corrosion inhibitlng compositions comprise the aminoamide o~ the general formula (I) above, or mixtures thereof, dissolved in an aliphatic, aromatic, alkyl-aromatic or cyclo-~l;ph~tic hydrocarbon solvent or a hydrocarbon polymer ordisper~ed in water or an aqueous-organic solvent mixture. The amount of the aminoamide or mixture thereof is in the range of 1 to 99% by weight of the composition. The amount is preferably 1 to 60% by weight and more preferably 10 to 50% by weight.

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, . , CA 02249171 1998-09-30 As a rule, corrosion takes the form of generalized corrosion, although other specialized forms also exist. Useful corrosion inhibition ~h~nisms can rely on neutralization of the corrosive agents, and/or by forming a protective film on the metal's tsurface. Increasing temperature generally causes corrosion rates to be accelerated. Increasing pressure can also accelerate corrosion because corrosive agents; like C02 and H2S, can be dissolved in the liquid phase up to a highly corrosive concentration. By using the aminoamides o~ the invention, the corrosive action of C0~, H2S, b~ines, oxygen and air can be controlled. Also these aminoamides can control corrosion caused by acids.

Aminoamide corrosion inhibitors of this invention neutralize acidic corrosive agents via the amino function. The amino group also allows for the attachment to the metal surface, ~orming a protective film. The inhibitors are characterized by their unexpected high thermal stability and therefore are capable of being used above 150~C or even above 190~C. lt has been found that the corrosion effectiveness is still very high at 290~ to 400~C and even at higher temperatures, e.g., at 450~C.

~orrosion protection can therefore be realized quite effectively by applying the aminoamides of this invention in those ~ields where other inhibitors fail. The aminoamides can'be applied per se or incorporated in a composition continuously at or up-stream of the area to be treated. Alternatively, it can be applied semi-continuously or in a batch ~nn~r at desired intervals of ..

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time. Under certain oilfield systems, the chemical can be applied via a "squeeze" type operation. In this case, the system is backflowed and the chemical is applied downstream o~ the in~n~e~ treating area. The backflowing causes the chemical to pass the target zone and proceed upstream of that area. The system is then flowed in the normal direction, and the chemical again passes the target zone. It is, of course, important that the chemical reach the point or points in the system where corrosive action occurs and this can be accomplished in various ways ~nown to the art-skilled. In flowing systems, use can be made of "stingers" in which the chemical is injected into the ~lowing stream, such as, for example, into a surge tank or a flow line. The aminoamides can also be incorporated into lubricant compositions which can simply be applied to the metal to be protected.

When the aminoamides of this invention are applied, and the system is at high temperature, or experiences sporadic high temperature/low temperature cycles, these materials will provide corrosion protection when typical ~;~;neS, imidazolines, and tetrahydropyrimidines or salts therefrom fail due to degradation.
Additionally, these amino~ i~es usually have better solubility characteristics than some of the current inhibitors. The _roved ~h.~ ~1 stability of these aminoamides will also mean that less gunking/fouling will be observed when they are used and thus it is not necessary to replace the steel parts frequently.

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~ CA 02249171 1998-09-30 , ~ , Potential applications where benefit ~rom the application o~
aminoamides from this invention can be realized include deep hot gas, oil, and geothermal producing wells with bottom hold temperatures above 150~C or even above 190~C, and refinery operations with system temperatures up to or even above about 4000C, especially where potential catalyst poisoning by heteroatom-cont~;n;ng materials would present a serious problem.
Coatings for the protection of metals at high temperatures can also bene~it from incorporating the aminoamide corrosion inhibitors of this invention as adjuvants to the coating's formulation.

The use of these aminoamides in lubricants, heat transfer fluids, and as additives ~or plastics for the protection o~ metallic surfaces against corrosion are further applications.

In respect to lubricants and metal:working fluids, U.S. Patents No. 4,210,542, No. 4,196,091, No. 4-,259,206 and No. 4,273,664 provide extensive discussion. By replacing the organo-nitrogen materials described in these patents with the aminoamides of the present invention, better thermal stability and better corrosion protection under similar stated circumstances can be achieved.

U.S. Patent No. 4,261,842 describes the use of amines as corrosion inhibitors in glass processing. The corrosion in-hibitors are used in aqueous media. The aminoamides of the present invention as salts or in cosolvents will perform in a superior manner if they are substituted for the organonitrogen materials disclosed in the patent.

..

' t . ,~ CA 02249171 1998-09-30 . . .

The methods and apparatus for employing corrosion inhibitors in refineries, in petroleum wells and in drilling operations are well known in the art and the ~; nor~ corrosion inhibitors of the present invention can be employed by replacing the previously employed inhibitors by than the invention. Exemplary reference is made to 'ICorrosion Inhibitors'l edited by C.C. Nathan, National Association of Corrosion Engineers, Eouston, Texas (1973) and particularly to pages 46-47, 65-68 and 81 and 106 and 108-111.

In connection with the employment of the amino~ s in plastics, it is noted that most plastics are manufactured ~rom monomers via catalysts. ~ost of the catalysts are acidic, and they are le~t within the ~inished plastic material. When such plastics are exposed to high temperature hostile environments, acidic materials are released, thereby causing corrosion to various metallic surfaces. Some of the corrosive agents released by the degradation of plastics are: hydrochloric acid, acetic acid, formic acid, formaldehyde, SOi, NOX, PO~ and H~. The equipment used to mold, extrude, shape, etc., can be corroded by the degrading plastics. The inhibitors of this invention can be incorporated into plastics at the time o~ manufacture, so that their further processing can have reduced corrosion.

Plastics are often used in various applications that experience hostile, high temperatures. These include actual hardware fabricated from plastic such as vessels, reactors piping, tanks, mixers, valves, etc., as well as coatings, adhesives, gaskets, sealants, and insulation ~or the e~uipment. By incorporating the ... . . . ... .. .... .. .
~ .. ..

.. ..

; CA 02249171 1998-09-30 aminoamide inhibitors of the invention into the plastics, corrosion of metals in contact with the plastics will be avoided.

Plastics which can be mentioned are: ABS (ACS, ASA), acetal homopolymers, acetal copolymers, polyvinylchloride, acrylics, bismaleimides, cellulosics, epoxies, fluoroplastics, ionomers, liquid crystal plastics, melamines, nitrile resins, nylons, phenolics, phenyleneresins,polyamide-polyimides,polyacrylates, polyarylsulfones; polymethacrylics, polybutylenes, polycarbonates, polyesters, thermoplastics, thermosets, polyetheretherketones, polyetherimides, polyethylenes, polyethylenes, polymethylpentenes, polystyrenes, polysulfones, polyurethanes, polyvinyls, vinyls, polysilicones, styrenic copolymers, polyureas, vinylidene chloride copolymers, and others, as well as mixtures of the above.

A similar issue is that of elastomers. These are natural rubbers, latexes, ethylene/acrylics, polythioethers, ethylene/-propylene copolymers, epoxidized natural rubbers, polyphenylene sulf ides, polyamide/polyimides, fluoroelastomers, silicone rubbers, phosphonitrilic fluoroelastomers, nitrile elastomers, epichlorohydrin elastomers. As with plastics, the amino~ es çan be incorporated in likc ~n~er.

A further potential use of the amindamides is for incorporation into cements (concrete) as well as into ceramics which are employed with metals. By incorporation of these inhibitors, corrosion of the contacting metal can be avoided.

. . ., ~

~,~ . . ..

~ ~ t . CA 02249171 1998-09-30 , The ~cope of this invention is illustrated, but not limited to, the following examples:
EX~MP~E 1 Preparation of Imidazoline from Tall Oil Fatty Acid and DiethYlenetriamine:
A 500 ml four-neck flask was charged with 251.12 grams of tall oil fatty acid (Acintol FA-2, Arizona Chemical Company) and 92.53 grams of diethylenetriamine (Union Carbide). The ~lask was equipped with a magnetic stirrer, pot thermometer, and a Barret trap with reflux condenser. The flask was placed under nitrogen, and heated to 250~C over 12 hours. The heating process used a ramping te~hn;que wit-h the foliowing temperature/time data:
105~/50 min., 157~C/115 min., 205~C/6 hours, 245~C/10 hours, 250~C/12 hours. During the heating period, 35 ml of condensate material was obtained in the trap; 29 ml was water cont~;n;ng abaut 1 gram of starting tr;~;n~, and 6 ml oily layer composed of triamine and lower molec~ ~ weight carboxylic acid residues.
The ramping t~chn;que ~; ;n;~hed the amount of foaming during the reaction in the pot. The reaction afforded 260 grams of the imidazoline product. This imidazoline was soluble in hexadecane, synthetic aromatic solvent (Alkylate 230, Monsanto), and p-cymene; it had a pour point of -32OC (ASTM D97-66); IR (neat~
3z65 (broad), 2915, 2845, 1605, 1460, 1255, 1013, 988, and 725 cm~~.

.

The ~atty acid composition o~ the employed Actinol FA-2 is as follows:
Palmitic Acid, % 0.1 Palmitoleic Acid, % 0.2 Unknown Acid, ~ 0.1 SteariC Acid, % 2.5 Oleic Acid, % 49.5 Unknown Acid, % 1.6 Linoleic Acid (cis-9, cis-12), % 35.7 Unknown Acid, ~ 3.1 .Unknown.Acid, ~ 0.4 Linoleic Acid ~cis-9, trans-11), ~ 2.6 Eicosanoic Acid, ~ 1.4 Linoleic Acid (trans-9, trans-11),~1.2 Eicosanoic Acid, % 0 5 Eioosatrienoic ACid, % O.4 Behenic Acid, % 0 7 'f ' "
. .

. ~ CA 02249171 1998-09-30 ~XAMPLE 2 Preparation of ~ oline from Tall Oil ~atty Aci~ ana Hydroxy-e~hyl--ethYlene~ ; ne A 500 ml four-neck flask was charged with 250.00 grams of tall oil fatty acid (Aaintol FA-2, Arizona Chemical Comp~ny) and 98.42 grams of N-hydroxyethylethylen~ m ine. The reaction was operated in the ~nn~r described in Example 1. After 12 hours, the reaction was halted. The temperature within the pot had risen to 248~C, and the trap cont~;ne~ 39 ml agueous layer and 8 ml oily layer. The reaction produced 302 grams of the imidazoline product. This imidazoline was not soluble in hexadecane, but was soluble in synthetic aromatic solvent ~- (Alkylate 230, Monsanto) and p-cymene; it had a melting point of 32-38~C; IR (neat) 3290, 2920, 2825, 1630, 1555, 1540, 1460, 1415, 1265 and 720 cm~l.

E~aMP~E 3 Preparation of N-Oleyl-1,3-Prop~ne~i~m;ne ~rom Oleylamine and 3-Chloro-l-amino~ro~ane:
A 500 ml three-neck flask was charged with 267.5 grams of oleylamine and 98.25 grams of 3-chloro-1-aminopropane. The flask was eguipped with magnetic stirrer, pot thermometer, and reflux condenser. The mixture was heated to 100~C for 20 hours, and ~hen cooled to room temperature. The crude mixture was poured into a separatory funnel, and 150 grams of water cont~;n;ng loo grams of sodium hydroxide was slowly added. Additional sodium hydroxide pellets were added until no more could be dissolved.
The mixture was shaken and two layers developed. The upper oily layer was removed, and placed into 250 ml dried tetrahydro~uran.

.:, . . ..
.. :.
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:i, . '.~ ~

. , CA 02249171 1998-09-30 The solution was dried with anhydrou5 ~odium carbonate, and the tetrahydrofuran removed at reduced pressure. In this way, 227 grams of the oleyldiamine were obtained- This fatty diamine had a melting point of 24-29~C, and was not soluble in h~xa~ec~ne~
synthetic aromatic solvent (Alkylate 230, Monsanto), or p-cymene;
IR (neat) 3210 (broad), 2920, 2850, 1605, 1460, 1375, 1130, 975 and 725 cm~~.

BX~MP~ 4 Preparation of Aminoamide from Tall Oil Fatty Acid and Isophorone Diamine A 100 ml three-neck flask was charged with 33.36 grams of tall oil fatty acid (-Acintol FA-2, Arizona Chemical Company) and 20.44 grams of isophorone ~;~;ne (Degamin IPDA, Degussa AG~. The flask was equipped with a magnetic stirrer, pot thermometer and a Barett trap with condenser. The reaction mixture was heated for one hour with the temperature being ramped from 180~C up to 306~C. About 0.1 gram of unreacted isophorone ~;~;n~ were found in the condensate. This process yielded 50.8 grams of the aminoamide product. The aminoamide had a pour point of -21~C
(AST~ D97-66) and was soluble in hexadecane, synthetic aromatic solvent (Alkylate 230, ~onsanto), and p-cymene; IR (neat) 3290, 3060, 2965, 2850, 1640, 1545, 1460, 1385, 1365, 1305, 1250, 1220, 970, and 75 cm~.

.. , . . .. ,__, ........ . .. , .. _ .. _. _ . . .. _ _ ._ = _ _ - -- .. . : . , . ,:

' . . , . CA 02249171 1998-09-30 .

- EXP~IPI.E 5 Preparation of Aminoamide from Tall Oil Fatty Acid and 1,8-~iamino-p-menthane A 100 ml three-neck flask was charged with 24.12 grams o* tall oil fatty acid (Acintol FA-2, Arizona Chemical Company) and 23.84 grams of 1,8-~i~ino-p-menthane (Aldrich Chemical Company). The flask was equipped with a magnetic stirrer, pot thermometer, and a Barret trap with a condenser. The mixture was heated for 85 minutes, up to a temperature o* 298OC, then cooled to room temperature. The trap contained 2.5 ml of water with 0.1 grams of starting diamine, and 0.6 ml of oily material. This procedure yielded 44.44 grams o* the aminoamide product. The aminoamide ~ product was not soluble in hexadecane, but was soluble in synthetic aromatic solvent (Alkylate 230, Monsanto) and ~-cymene;
IR (neat) 3280, 3050, 2910, 2840, 1630, 1535, 1445, 1360, 1270, 1173, 1135, 970, 812 and 722 cm~l.

;~

~ CA 02249171 1998-09-30 .. .
.

Preparation of Aminoamide from Tall Oil Fatty Acid and m-Xyly-lenediamine A 100 ml three neck fla5k was charged with 53.83 grams of tall oil fatty acid (Acintol FA-2, Arizona Chemical Company) and 25.88 grams of m-xylenediamine (Aldrich Chemical Company). The flask was equipped with a magnetic stirrer, pot thermometer, and a Barret trap with condenser. The mixture was heated for one hour, with the pot temperature reaching 266~C. The mix was cooled.
The trap contained 3.3 ml of water with 0.1 grams of unreacted diamine. This procedure afforded 75.07 grams of the aminoamide product. This aminoamide product had a melting point o~ 34-43~C, and was not soluble in hexadecane, but was soluble in synthetic aromatic solvent (Alkylate 230, Monsanto) and ~-cymene: IR
(neat) 3190, 3050, 3010, 2900 (broad), 1655, 163~, 1610, 1560, 1545, 1525, 1465, 1440, 1425, 1380, 1350, 1330~ 1250, 1160 lQ~9, 895, 795, and 705 cm~1.

, E~AMPL~ 7 Preparation of Aminoamide from Tall Oil Fatty Acid and 1,4-PhenYlenediamine A 100 ml three-neck flask was charged with 36.14 grams of tall oil fatty aaid (Acintol FA-2, Arizona Chemical C _Any) and 14.06 grams of 1,4-phenylen~i A~; ne (Aldrich Chemical Company). The flask was e~uipped with a magnetic stirrer, pot thermometer, and a Barret trap with condenser. The mixture was heated ~or one hour with the pot attA;ning a temperature of 282OC. The mixture was cooled. The trap contained 2.2 ml of water with 0.1 grams of unreacted diamine. This process yielded 47.69 grams of the ... _.. , . , _ _ _ _ _ . ................................................ .
: '~ ' ' ' ' . "' .
,~ , , .

~ CA 02249171 1998-09-30 f .

aminoamide product. This aminoamide had a melting point o~ 84-91~C, and was not soluble in hexadecane, synthetic aromatic solvent (Alkylate 230, Monsanto) or ~-cymene; IR (neat) 3360, 3345, 3290, 3000, 2910, 2840, 1645, 1590, 1520 (broad), 1455, 1420, 1395, 1370, 1300, 1255~ 1180, 1110, 1090, 960, 830, 710 (broad) and 505 cm-~.

Preparation of Aminoamide ~rom Tall Oil Fatty Acid and 1,~-Diaminooctane A 100 ml flask was charged with 38.,92 grams o~ tall oil ~atty acid (Acintol FA-2, Arizona Chemical Company) and 20.2 grams of 1,8~ r; nooctane (Aldrich Chemical Company). The flask was ~itted with a magnetic stirrer, pot thermometer, and a Barret trap with condenser. The mixture was heated for 34 minutes, with the pot reaching 246~C. The mixture was then cooled. The trap cont~;n~ 2.5 ml water with 0.1 gram of unreacted ~;~;ne, This reaction af~orded 51.75 grams of the A~;no~ e product. The aminoamide had a melting point of 54-70~C, and was not soluble in hexadecane, synthetic aromatic solvent (Alkylate 230, Monsanto), or ~-cymene; IR (neat) 3210, 3050, 3010, 2800 (broad), 1630j 1545, 1525, 1460, 1418, 1375, 1260, 1228, 1194, 1076, 945, 820, 725 (s, broad), and 565 cm~l.

- - :, . .

CA 02249l7l l998-09-30 EX~MPLE g Preparation of A~; noA~; de from Tall Oil Fatty Acid and D;~; nn -methYlnorbornylene A 100 ml three-neck flask was charged with 33.36 g of tall oil fatty acid (Acintol FA-2, Arizona Chemical Company) and 18.51 grams of diaminomethylnorbornylene (NBDA, Mitsui Toaksu Chemicals, Inc.). The flask was equipped with a magnetic stirrer, pot thermometer, and a Barret trap with condenser. The mixture was heated for 45 minutes and the pot attained a temperature of 306~C. Afterwards, the mixture was cooled. the trap contained 2.0 ml water with 0.1 gram unreacted ~; ; ne .
This method provided 48.88 grams of the aminoamide. The amino-amide was not soluble in hexadecane, but was soluble in synthetic aromatic solvent (Alkylate 230, ~onsanto) and ~-cymene; it has a pour point of -17~C (ASTM D97-66); IR (neat) 3280, 3065, 3005, 2920, 2850, 1630, 1545, 1455, 1378, 1260, and 725 cm~l.

~XAMPLE 1o Preparation of Aminoamide from Tall Oil Fatty acid and 2,2,4-Tri-methYl-1 6-hexanediamine A 100 ml three-neck flask was charged with 33.36 grams of tall oil fatty acid (Acintol FA-2, Arizona Chemical Company) and 19.0 grams of 2,2,4-trimethyl-1,6-hexan~ ~;ne (Vestamin TMD, Huls).
The flask was fitted with a magnetic stirrer, pot thermometer, and a Barret trap with condenser. The mixture was heated for 33 minutes with the pot att~;n;ng 268~C. The mixture was then cooled. The trap contained 2.1 ml water with 0.1 gram of hnreacted diamine. The procedure yielded 49.26 grams of the aminoamide product. The aminoamide had a pour point of -22OC

S ; - -, - . . .

. . .

~ .- ,' CA 02249171 1998-09-30 .
(ASTM D97-66), and was soluble in h~cAne~ synthetic aromatic solvent (Alkylate 230, Monsanto), and ~-cymene; IR (neat) 327s, 3025, 2997, 2915, 2845, 1635, 14G0, 1365, 1255, and 725 cm~l.

~XAMPLE 11 Thermal Degradation Studies at 290~c under Air with 1010 Mild Steel One ml glass ampules were filled with a 0.25 ml sample along with 4 cm oP 22 gauge 1010 mild steel wire. The ampules were sealed under air and placed in a muffle furnace at a constant t m,?rature o~ 290~C. Over time, ampules were removed from the furnace and cooled, then opened. The contents were subjected to infrared analyses. The ratio of the absorbances of the chemical's active frequency versus that of an inactive hydrocarbon frequency was determined, and these were then norr~;zed to the ratio for the untreated case. Table 1 shows the infrared frequencies used for each chemical evaluated, and Table 2 displays the normalized data versus time.

_.. _, _ . . _ . _ _ . . . . ..
~( ' , ;~. ' ,:

~ ' ,' CA 02249l7l l998-09-30 , Table 1 - Infrared Freouencies for Evaluated Chemicals Inactive Example Number of ChemiCal Active Freguency Freguency Evaluated (c~) (cm~l) 2 . 1630 1460 All infrared freguencies given in Table 1 were obtained by the analysis of neat samples in a Beckman ACc~ h 6 double beam spectrophotometer using KBr salt plates. The active fre~uencies ~or Example 1 and 2 are the i ;~zoline bands; i~or Example 3, it was the secondary amine; for all others, it was the ~;no~mide carbonyl.

.. . _ .. . . _. .,............. _ ' . _ . .
, ~ ~
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Table 2. Degradation Data for Various Chemicals at 290~C under Air with 1010 Mild 5teel No~ ed Ratio (active/inactive) Example h~t- @lO hr@ 20 hr @30 hr@ 40 hr@50 hr 1 0.98 0.97 0.96 0.955 0.95 2 0.95 0.895 0.865 0.845 0.83 3 0.51 0.38 0.3 - _ 4 0.99 0.98 0.97 0.935 0.92 0.965 0.94 0.9 0.85 0.81 6 0.805 0.62 0.46 7 0.94 0.875 0.82 0.78 0.74 8 0.93 0.87 0.83 9 0.98 0.95 0.93 0.94 0.94 0.97 0.965 0.95 0.94 0.93 The data in Table 2 suggest that the chemicals of Examples 1, 4, 9 and 10 are reasonably stable under the test conditions, since after 2 days exposure, better than 90% of the active material was still present. The ch~;c~l~ of Examples 2, 5, 7 and 8 did degrade, but after 1 day better than 80~ o~ the original active material still remained. The chemicals of Examples 3 and 6 di~played significant degradation.

EXAMP~E 12 ~h~r~-l Degradation Studies at 315~C under Air with 1010 ~ild Steel The method of Example 11 wa~ repeated, except that the mu~fle furnace was set at 315~C for this series of runs. The infrared frequencies cited in Table 1 were also used in the acquisition of data for this series as well as those of Example 13, and the normalized data appearing in Tables 3 and 4, respectively.

' ~

.' CA 02249171 1998-09-30 Table 3. Degradation Data of Various Chemicals at 315~C unde~ A;r with 1010 Mild Steel Normalized Ratio (active/inactive) Example Number @ 5 hr~ 10 hr@ 20 hr@ 30 hr~ 40 hr 1 0.8 0.67 0.47 0.34 0.225 2 0.860.765 ~0.635 0.54 3 0.5050.35 0.235 - .
4 0.9750.955 0.905 0.86 0.83 0.9050.825 0.75 6 0.68 0.555 7 0.89 0.82 0.755 0.67 0.57 8 0.78 0.61 - - - .
9 0.95 0.925 0.88 0.83 0.78 0.93 0.91 0.88 0.82 0.745 The above data show that for the chemicals of Examples 4, 9 and .
10, good thermal stability can be realized; greater than 85~ o~ , the original active material is present after 24 hours under the cited conditions. The chemicals of Examples 2, 5 and 7 are considered to be marginal, while those of Examples 1, 3, 6 and-8 display significant degradation.

EX~MPL~ 13 ~h~ ~1 Degradation studies at 340~ under Air with 1010 ~ild Steel The method of Example 11 was repeated, but that the muffle -furnace was set at 340~C for this series of runs. The nol ~li7-ed data appear in Table 4.

' ' ' CA 02249171 1998-09-30 , , - Table 4. Degradation Data for Various Chemicals at 340~C under Air with 1010 Mild Steel Nol 91- ~ed Ratio (active/inactive) Example Number @ 1 hr @ 4 hr @ 7 hr @ 10 hr~ 20 hr 1 0.7~ 0.47 0.33 - -2 0.81 0.64 0.43 - -3 0.61 0.4 0.33 0.27 4 0.87 0.805 0.71 0.67 0.555 , 5 0.97 0.82 0.7 0.62 0.41 6 0.42 0.92 0.71 0.595 0.505 8 0.84 0.64 - - -9 0.965 0.835 0.715 0.675 - ~' Ø97- 0.92' 0.87 0.825 0.67 The above data show that the chemicals from Examples 4, 5, 9 an~
10 are more thermally stabile under the reaction conditions than the other materials. In these cases, better than 5'0~ of the active material is present at 15 hours.

EX~MP~E l~A

~hermal Degradation Studies of 40% Active Synthetic Aromatic Solven~ Materials at 340~C under Air with 1010 Mild Steel One ml ampules were charged with 0.25 grams of 40% (by weight) solutions cont~in;ng the chc~;c~l to be evaluated in synthetic aromatic solvent (Alkylate 230, Monsanto), and 4 cm of 22 gauge 1010 mild steel wire. The ampules were then sealed under air, and placed into a muffle furnace at 340OC. At various times, some of the ampules were remov,ed, cooled and opened. The contents were evaluated by infrared spectroscopy. As in Example 11, normalized ratios of absorb~nc~-~ for active to inactive ., .

... .
~,, . , . .- .
.

~ ' CA 02249l7l l998-09-30 . ~ _ absorh~nc~s were det~rr;ned. Table 5 shows the ~re~uencies used ~or the chemicals evaluated, while Table 6 contains the normalized data describing degradation.

Table 5. In~rared Frequencies ~or Evaluated Chemicals in Solvent . .
Example Number o~ Active Fre~uency Inactive Frequency Chemical Evaluated (cm~l) (cm~l) Table 6. Degradation Studies ~or 40% Active Solutions Oe Various Chemicals at 340~ under Air with 1010 Mild Steel Norma ized Ratio (act-ve/inac ive) Example Number @ 1 hr@ 2 hr @ 5 hr @10 hr@20 hr@50 hr 0.72 0.64 0.43 0.335 0.075 2 0.46 0.33 0.19 0.165 0.09 4 0.97 0.945 0.875 0.805 0.66 0.415 0.93 0.9 0.82 0.695 0.605 0.25 6 0.73 0.48 0.27 0.17 0.06 9 O.9Z 0.8 0.685 0.625 0.57 0.36 0.98 0.96 0.95 0.93 0.865 0.555 These data show that the chemicals of Examples 4 and 10 are the most stable under these conditions. Chemicals prepared by Examples not listed in Tables 5 and 6 were not evaluated since .' CA 02249171 1998-09-30 they are not soluble in the aromatic solvent; the chemicals listed in Tables 5 and 6 can be formulated into heavy aromatic solvent without using a cosolvent.

EXAMP~E 14B

Thermal Degradation Studies of 40% Active Synthetic Aromatic Solvent Materials at 400~c under Air with 1010 Mild Steel One ml ampules were charged with 0.25 grams of 40% (by weight) solutions cont~; n i ng the chemical to be evaluated in synthetic aromatic solvent (Alkylate 230, Monsanto), and 4 cm 22 gauge 1010 mild steel wire. The ampules were then sealed under air, and placed into a muf~ie furnace at 400~C. At various times, some of the ampules were removed, cooled, and opened. The contents were analyzed by infrared spectroscopy. As in Example 11, noL ~ ed ratios of absorbances for active to inactive absorbances were det~rr;ned. The fre~uencies used for this Example are those shown in Table 5 of Example 14A. srable 6.5 displays the normalized data which describe the degradation.

.. ..
~ ': . .. s t ,~ CA 02249171 1998-09-30 Table 6.5. Degradation Studie5 for 40% Active Solutions o~ Various Chemicals at 400~ under Air with 1010 Mild Steel Normalized Ratio (act ve/inactive) Example Number @O.lhr @0.2hr @0.4hr @0.6hr ~0.8hr *~1~ h~
1 0.76 0.6 0.320.22 0.14 0.07 2 0.8 0.6 0.370.32 0.17 0.01 4 o.99 0.98 0.860.71 0.56 0.4 o.g 0.78 0.580.41 0.28 0.15 6 0.58 0.15 0.1 0.06 0.05 0.04 9 0.87 0.77 0.520.34 0.23 0.12 ~o ~ 0.96 0.92 0.820;68 0.51 0.34 'hese data suggest that chemicals 4 and lC are the ~ost stLble under the reaction conditions.

EX~MPLE 15 Evaluation o~ Various Chemicals as Corrosion Inhibitors in Rotating Wheel Test Using ASTM Brine and Crude Oil at 60~C ~or 24 hours with 1010 Mild Steel Coupons A variation of NACE ID182, Item 54238, test for corrosion inhibition was used to evaluate the chemicals of Example 1 through 10. Seven ounce glass bottles were charged with 50 ml brine (ASTM D-1141) and 50 ml dehydrated California crude oil (API gravity of 26.9~), and the appropriate amount of test c-he ic~l (1% in xylenes). The brine was purged ~or 4 hours with a stream of carbon dioxide gas. The bottles were sealed under a ~our second purge o~ hydrogen sulfide gas (displacing nitrogen overhead vapors), a~ter the addition of a cleaned, preweighed 1010 mild steel coupon. The bottles were placed on a rotating wheel apparatus for 24 hours at an isothermal temperature of 60~C. Afterwards, the coupons were removed from the bottles, :, -. . . .,, _.., . .. _ . . ...
.

' - ~ CA 02249l7l l998-09-30 .

.

cleaned and reweighed. Untreated blank coupons were also run for each wheel test group. The percent protection was then calculated via the following fo~

% Protection = (100%)(B1ank Weight Loss - Test Coupon Weight Loss) Blank Weight Loss Table 7. Percent Protection for Various Chemicals Percent Protection Example Q @ ~ @ @
Number 3 ppm 10 ppm 25 ppm 50 ppm 100 ppm 8 .49 .55 ~58 61 62 The data in Table 7 show that the chemical in Example 1 gives excellent protection to mild steel when it is not subjected to high temperature degradation. Good protection is provided by the chemicals oe Examples 2, 3, 4 and 9. Fair protection is provided by the chemicals oE Examples 5 and lo at high use conc~ntrations.
Poor protection by the chemicals o~ Examples 6, 7 and 8 are suggested by this test procedure.

' ' ' ' ' ''' .

' - CA 02249171 1998-09-30 , . . --Evaluation of Various Chemicals a~ter beinq Heat Treated at 315~C
The method of Example 15 was repeated, but by using the same chemicals after they were exposed to 315~C for 24 hours in sealed tubes. The results are displayed;in Table 8.

Table 8. Percent Protection for ~arious Heated Treated (315~) Chemicals Percent 'rotection Example @ ~ @ ~ @
Number 3 ppm10 ppm 25 ppm50 ppm100 ppm ', 1 23 30 40 47 54 The data in Table 8 show that the chemicals of Examples 4, 5, 9 and 10 provide good corrosion protection a~ter being subjected to 315~C ~or 24 hours. The other chemicals display poor protection to mild steel in this test condition.

~

C

r . . CA 02249171 1998-09-30 .

EXAMP~B 17 ~valuation of Various Chemicals after beinq Heat Treated at 340~C
The method of Example 15 was repeated, except that the chemicals to be evaluated were heated to 340OC for 24 hours in sealed tubes. The data are shown in Table 9.

Table 9. Percent Protection for Various Heat Treated (340~C) Chemicals Percent Protection Example @ @ @ ~ ~
Number 3 ppm10 ppm25 ppm50 ppm100 ppm The data in Table 9 show that the chemicals of Examples 4 and 10-provide good protection at average and high use concentrations.
The chemical~ o~ Examples 5, 7 and 9 show ~air protection at high use concentrations, while the r~;n;ng chemicals provided poor protection to lolO mild steel under the test conditions.

The aromatic aminoamide of Example 7 showed a slightly lower protection than the cyclo~l;ph~tic aminoamides of Examples 5 and 9_ . .

.

., . ., =. .,~

.
, :,~, . . . -The corrosion experiments show that aminoamides in line with the general formula of the present invention have much higher corrosion inhibiting efficiency than aminoamides with an aromatic ring in the molecule, the special ~ ne of Example 3 and the aminoamides with an imidazole ring.

Evaluation of Various Chemicals in a Sealed Autoclave at 320O
Under Pressure A 800 m~ SS-316 autoclave (Parr Model 4841) was charged with 70 ml 6~ ASTM brine, 70 ml crude oil having an API gravity of 22.1~, and a magnetic stirring bar. Preweighed and cleaned mild steel 1010 coupons were fitted to the lid of the autoclave so thàt when sealed, the coupons were partially immersed within the stirred fluids. When a test inhibitor was used in a run, it was injected into the fluid mixture at 100 ppm using a micropipet. Once the autoclave was sealed, it was pressured up to 500 PSIG with a gaseous mixture containing 98.8% methane, 1.0% carbon dioxide, and 0.2 hydrogen sulfide. The system was heated externally to 320OC, and held there for 24 hours. The resulting pressures were recorded ~or the 320~C condition. Afterwards, the system was cooled to room temperature, and opened. The coupons were removed, cleaned, reweighed, and inspected. The results are shown in Table 10.
, ., . . ... . ... . . ~
-;.

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Table 10 Chemical System %
Evaluatea Pressure Protec~ion Comments Discoloration and Gunking, General and 2250 - Pitting Corrosion Example 1 2440 PSIG 11.4 Observed Example 4 2280 PSIG 41.6 General corrosion Seen Slight Discoloration and General Example 5 2320 PSIG 33.3 Corrosion Seen Example 10 2260 PSIG 44.6 General Corrosion seen These results show the aminoamides o~ this invention give good inhibition at high temperatures under pressure, and that typical.
imidazolines ~ail.

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Claims (56)

1. In a method for inhibiting corrosion on a metal surface which comprises bringing into contact with said metal surface an effective amount of a corrosion inhibitor, the improvement wherein the corrosion inhibitor is an aminoamide of the general formula R1-CO-NR2-Z-NR3R4 (I) wherein Z is a divalent aliphatic radical having a branched carbon chain or a divalent alicyclic ring system including ring systems with one or two attached alkylene groups and/or alkyl groups which said radicals comprise a carbon chain with at least three carbon atoms between the attached NR2- and NR3R4 groups and wherein the structural element -NR2-Z-NR3R4 of formula (I) does essentially not form an imidazoline or tetrahydropyrimidine ring system, R2, R3, R4 are each, independently of the other, hydrogen, an aliphatic, alicyclic or aromatic radical, and R1 is a monovalent monomer or polymer radical having an oleophilic portion comprising a saturated or olefinic linear or branched hydrocarbon radical, an alicyclic or an aromatic radical, or a salt thereof.

2. A method according to claim 1 wherein R1 is alkyl, alkenyl or alkadienyl of 3 to 30 carbon atoms.

3. A method according to claim 1 wherein R1 is a linear alkyl or alkenyl group of 7 to 22 carbon atoms.

.

4. A method according to claim 1, wherein R2, R3 and R4 are the same or different and each is hydrogen or alkyl of 1 to 5 carbon atoms.

5. A method according to claim 1, wherein R1 is a linear alkyl or linear alkenyl group of 7 to 22 carbon atoms or a mixture of said groups and R2, R3 and R4 are the same or different and are hydrogen or alkyl of 1 to 3 carbon atoms.

6. A method according to claim 1, wherein Z is a branched alkylene group having 6 to 10 carbon atoms and having 4 to 6 carbon atoms between the attached amino groups.

7. A method according to claim 1, wherein Z is a divalent hydrocarbon radical having 6 to 12 carbon atoms or a mono-, bi- or tricyclic five- and/or six- membered ring system.

8. A method according to claim 7, wherein Z is a cycloaliphatic ring system.

9. A method according to claim 1, wherein the corrosion inhibitor is a reaction product of a higher fatty acid with isophorone diamine, 2(3),5(6)-diaminomethyl-norbornylene or 1,8-diamino-p-menthane.

10. A method according to claim 1, wherein the corrosion inhibitor is a reaction product of a higher fatty acid with 2,2,4-trimethyl-1,6-diaminohexane.

11. A method according to claim 1, wherein the corrosion inhibitor in neat form is brought into contact with the metal surface.

12. A method according to claim 1, wherein the corrosion inhibitor in liquid phase is contacted with the metal surface.

13. A method according to claim 1, wherein the metal surface is contacted with the corrosion inhibitor at a temperature of above 150°C.

14. A method according to claim 12, wherein the liquid phase comprises an aromatic, aliphatic, cycloaliphatic or alkylaromatic hydrocarbon solvent.

15. A method according to claim 13, wherein the contact is made under a pressure of above 9MPa.

16. A method according to claim 1, wherein corrosion of metal surfaces of metal equipment in gas or oil wells is inhibited and wherein said corrosion inhibitor is injected into said gas or oil well in neat form, as a solution or as a dispersion, said injection being batchwise or continuous.

17. A method according to claim 1, wherein the metal surface to be protected is selected from the group consisting of mild (carbon) steel, wrought irons, cast irons and stainless steels.

18. A method according to claim 1, wherein the corrosion inhibitor is brought into contact with the metal surface by a batchwise or continuous treatment.

19. A method according to claim 1, wherein the corrosion inhibitor is brought into contact with the metal surface by dipping, spraying or smearing the metal surface with the inhibitor in neat form or in liquid phase.

20. A method according to claim 1 wherein the metal surface is protected against corrosion caused by acids, CO2, H2S, brines, oxygen or air or mixtures thereof.

21. A method according to claim 1, wherein corrosion of metal surfaces in deep hot gas wells, deep hot petroleum wells, refinery operations or deep hot geothermal wells is inhibited.

22. A method according to claim 1, wherein the corrosion inhibitor is the reaction product of a higher fatty acid and isophorone diamine.

23. A method according to claim 22, wherein the higher fatty acid is tall oil fatty acid.

24. A method according to claim 1, wherein the corrosion inhibitor is the reaction product of a higher fatty acid and a member selected from the group consisting of 1,8-diamino-p-menthane, diamino-methylnorbornylene and 2,2,4-trimethyl-1,6-hexanediamine.

25. A method according to claim 24, wherein the higher fatty acid is tall oil fatty acid.

26. A method according to claim 1, wherein corrosion inhibition is achieved at a temperature in the range of about 190° to 450°C.

27. A method according to claim 26, wherein the temperature is in the range of about 290° to 400°C.

28. A method according to claim 1, wherein the inhibitor is employed in a flowing liquid system in an amount of about 1 to 100 parts per million parts of liquid.

29. A method according to claim 1, wherein the inhibitor is employed in a static liquid system in an amount of about 1 to 10,000 parts per million parts of liquid.

30. A method according to claim 1, wherein the corrosion inhibitor is incorporated into a plastic to inhibit corrosion of a metal surface contacted by said plastic.

31. A method according to claim 30 wherein the corrosion inhibition is of metal surfaces contacted by said plastic in molten form.

32. A composition for inhibiting corrosion of a metal surface which comprises 1 to 99% by weight of the composition of an aminoamide of the general formula R1-CO-NR2-Z-NR3R4 (I) wherein Z is a divalent aliphatic radical having a branched carbon chain or a divalent alicyclic ring system including ring systems with one or two attached alkylene groups and/or alkyl groups which said radicals comprise a carbon chain with at least three carbon atoms between the attached NR2- and NR3R4 groups and wherein the structural element -NR2-Z-NR3R4 of formula (I) does essentially not form an imidazoline or tetrahydropyrimidine ring system, R2, R3, R4 are each, independently of the other, hydrogen, an aliphatic, alicyclic or aromatic radical, and R1 is a monovalent monomer or polymer radical having an oleophilic portion comprising a saturated or olefinic linear or branched hydrocarbon radical, an alicyclic or an aromatic radical, or a salt thereof.

33. A composition according to claim 32 comprising 1 to 60% by weight of the aminoamide.

34. A composition according to claim 32, comprising 10 to 50%
by weight of the aminoamide.

35. A composition according to claim 32, wherein the aminoamide is dissolved in an aliphatic, aromatic, alkylaromatic or cycloaliphatic hydrocarbon or mixtures thereof or is dispersed in water or an aqueous-organic solvent mixture.

36. A composition according to claim 32, wherein R1 is alkyl, alkenyl or alkadienyl of 3 to 30 carbon atoms.

37. A composition according to claim 32, wherein R1 is a linear alkyl or alkenyl group of 7 to 22 carbon atoms.

38. A composition according to claim 32, wherein R2, R3 and R4 are the same or different and each is hydrogen or alkyl of 1 to 5 carbon atoms.

39. A composition according to claim 32, wherein R1 is a linear alkyl or linear alkenyl group of 7 to 22 carbon atoms or a mixture of said groups and R2, R3 and R4 are the same or different and are hydrogen or alkyl of 1 to 3 carbon atoms.

40. A composition according to claim 32, wherein Z is a branched alkylene group having 6 to 10 carbon atoms and having 4 to 6 carbon atoms between the attached amino groups.

41. A composition according to claim 32, wherein Z is a divalent hydrocarbon radical having 6 to 12 carbon atoms or a mono-, bi- or tricyclic five- and/or six-membered ring system.

42. A composition according to claim 41 wherein Z is a cycloaliphatic ring system.

43. A composition according to claim 32, wherein the aminoamide is a reaction product of a higher fatty acid with isophorone diamine, 2(3),5(6)-diaminomethyl-norbornylene or 1,8-diamino-p-menthane.

44. A composition according to claim 32, wherein the aminoamide is a reaction product of a higher fatty acid with 2,2,4-trimethyl-1,6-diaminohexane.

45. A composition according to claim 43, wherein the aminoamide is a reaction product of tall oil fatty acid with isophorone diamine.

46. A composition according to claim 32, wherein the aminoamide is a reaction product of tall oil fatty acid and a member selected from the group consisting of 1,8-diamino-p-menthane, diamino-methylnorbornylene and 2,2,4-trimethyl-1,6-hexane-diamine.

47. An aminoamide of the general formula said aminoamide being the reaction product of an amine of the formula with R1-COOH or a reactive derivative thereof wherein Z is a divalent aliphatic radical having a branched carbon chain or a divalent alicyclic ring system including ring systems with one or two attached alkylene groups and/or alkyl groups which radicals comprise a carbon chain with at least three carbon atoms between the attached NR2- and NR3R4 group and wherein the structural element -NR2-Z-NR3R4 of the formula does essentially not form an imidazoline or tetrahydropyrimidine ring system, R2, R3, R4 are each, independently of the other, hydrogen, an aliphatic, alicyclic or aromatic radical, and R1 is a monovalent monomer or polymer radical having an oleophilic portion comprising a saturated or olefinic linear or branched hydrocarbon radical, an alicyclic or an aromatic radical, or a salt thereof, with the proviso that fatty acid amides of isophorone diamine and diamidotriamines based on glutamic acid are excluded.

48. An aminoamide according to Claim 47, wherein R1 is alkyl, alkenyl or alkadienyl of 3 to 30 carbon atoms.

49. A aminoamide according to claim 47, wherein R1 is a linear alkyl or alkenyl group of 7 to 22 carbon atoms.

50. An aminoamide according to claim 47, wherein R2, R3 and R4 are the same or different and each is hydrogen or alkyl of 1 to 5 carbon atoms.

51. An aminoamide according to claim 47, wherein R1 is a linear alkyl or linear alkenyl group of 7 to 22 carbon atoms or a mixture of said groups and R2, R3 and R4 are the same or different and are hydrogen or alkyl of 1 to 3 carbon atoms.

52. An aminoamide according to claim 47 wherein Z is a branched alkylene group having 6 to 10 carbon atoms and having 4 to 6 carbon atoms between the attached amino groups.

53. An aminoamide according to claim 47, wherein Z is a divalent hydrocarbon radical having 6 to 12 carbon atoms or a mono-, bi- or tricyclic five- and/or six- membered ring system.

54. An aminoamide according to claim 53, wherein Z is a cycloaliphatic ring system.

55. An aminoamide according to claim 47, which is a reaction product of a higher fatty acid with a member selected from the group consisting of 1,8-diamino-p-menthane, diaminomethyl-norbornylene and 2,2,4-trimethyl-1,6-hexanediamine.

56. An aminoamide according to claim 55, wherein the higher fatty acid is tall oil fatty acid.