WO2017112721A1

WO2017112721A1 - Corrosion inhibitors and related processes for their production and use

Info

Publication number: WO2017112721A1
Application number: PCT/US2016/067908
Authority: WO
Inventors: Se Hye KIM; Joseph M. O'DAY; Thanikavelu Manimaran; Srinivasa S. GODAVARTHY
Original assignee: Albemarle Corporation
Priority date: 2015-12-22
Filing date: 2016-12-21
Publication date: 2017-06-29

Abstract

Corrosion inhibiting compositions and related processes for their production and use are described in this disclosure. The composition includes one or more quaternary ammonium halides. The one or more quaternary ammonium halides include a quaternary ammonium cation and a counterion. The counterion has a charge sufficient to balance the positive charge on the quaternary ammonium cation.

Description

Corrosion Inhibitors and Related Processes for Their Production and Use

TECHNICAL FIELD

[0001] The present disclosure generally relates to quaternary ammonium halide compositions and related processes, and more particularly to quaternary ammonium halide compositions for inhibiting corrosion of a material in a concentrated acid solution, processes for preparing such compositions, and processes for using such compositions.

BACKGROUND

[0002] Acid treatments are frequently utilized in the oil and gas industry to improve a well's productivity or injectivity. An acid treatment typically involves pumping acid through a pipeline into a wellbore or geologic formation. Commonly used acid solutions can include organic acids (e.g., citric, formic, acetic acid, etc.) and mineral acids (e.g., hydrochloric or hydrofluoric acid). Although acid treatments are generally effective in improving a well's productivity or injectivity, the acid solutions used can cause corrosion of the metallic surface of the pipeline. To protect pipelines from corrosion during acid treatment, corrosion inhibitors are often used to protect the pipeline against corrosion.

[0003] Prior efforts at reducing pipeline corrosion in acid treatments have typically employed amine based corrosion inhibitors. However, such inhibitors can be unstable and degrade under the harsh conditions that are often present in oil wells (e.g., high temperature, high pressure and so forth), which can lead to the formation of heat stable ammonium salts (HSS) that can cause corrosion of the pipeline. In addition, many organic and inorganic inhibitors are toxic, very expensive and environmentally unfriendly.

[0004] Thus, there remains a need in the art for a corrosion inhibitor having

chemical/physical stability under the harsh conditions present in wellbores. In addition, a need remains in the art for a corrosion inhibitor capable of being efficiently adsorbed onto a metallic surface to form protective layer on the metallic surface. A need also remains in the art for a more environmentally friendly corrosion inhibitor.

[0005] Contained herein is a disclosure directed to resolving, or at least reducing, one or more of the problems mentioned above, or other problems that may exist in the art. NON-LIMITING BRIEF SUMMARY OF THE INVENTION

[0006] The present disclosure generally relates to one or more compositions suitable for inhibiting corrosion of a metal or metallic surface that is in contact with a concentrated acid solution and related processes for the production and use of the one or more compositions. In an aspect, the composition includes one or more quaternary ammonium halides (I):

wherein R¹ is an alkyl group having about 10 to about 20 carbon atoms, R² is an alkyl group having about 1 to about 4 carbon atoms, R³ is an alkyl group having about 1 to about 4 carbon atoms, R⁴ is an alpha alkyl omega aryl group, and X¹ is Br. Among the many different possibilities contemplated, the alpha alkyl omega aryl group may be substituted with a halide or an alkyl group, for example, an alpha alkyl omega benzyl group substituted with a halide or an alkyl group. It is further contemplated that R¹ may be an alkyl group having about 14 to about 18 carbon atoms. It is still further contemplated that the quaternary ammonium halide (Γ) may be cetyldimethylbenzylammonium bromide, tetradecyldimethylbenzylammonium bromide, octadecyldimethylbenzylammonium bromide, a mixture of

alkyl dimethylbenzylammonium bromides wherein the number of carbon atoms comprising the alkyl group is from about 10 to about 18 carbon atoms, and/or mixtures thereof.

[0007] According to another aspect, the composition includes one or more quaternary ammonium halides (II):

wherein A is monocyclic or bicyclic heteroaromatic ring group substituted with a halide, R⁵ is an alkyl group having about 10 to about 20 carbon atoms, and X² is Br, CI, or I. Among the many different possibilities contemplated, R⁵ may be an alkyl group having about 14 to about 18 carbon atoms. It is still further contemplated that the quaternary ammonium halide (ΙΓ) may be, for example, 3-bromocetylpyridinium bromide.

[0008] According to another aspect, an effective amount of the composition(s) described herein is/are added to the concentrated acid solution in contact with the metal or metallic surface. The one or more quaternary ammonium halides is/are present in the composition in the range from about 5 ppm to about 50,000 ppm, more preferably in the range from about 10 ppm to about 100 ppm. It is further contemplated that the concentrated acid solution may include hydrochloric acid (HQ), hydrofluoric acid (HF), sulfuric acid (H₂S0₄), hydrobromic acid (HBr), and/or mixtures thereof. It is still further contemplated that when the concentrated acid solution contains H₂S0₄, and H₂S0₄ is present in a concentration in the range from about 3 wt.% to about 70 wt.%. It is still further contemplated that when the concentrated acid solution contains HQ, the HQ is present in a concentration in the range from about 3 wt.% to about 37 wt.%. It is still further contemplated that when the concentrated acid solution contains HBr, the HBr is present in a concentration in the range from about 3 wt.% to about 62 wt.%.

[0009] According to another aspect, the composition(s) described herein are produced by combining an aryl alcohol with an inorganic halide acid (e.g., HBr) to form an intermediate product mixture which is then combined with a tertiary amine thereby producing a mixture of one or more quaternary ammonium halides described herein.

[0010] While multiple embodiments are disclosed, still other embodiments will become apparent to those skilled in the art from the following detailed description. As will be apparent, certain embodiments, as disclosed herein, are capable of modifications in various obvious aspects, all without departing from the spirit and scope of the claims as presented herein. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0011] The accompanying drawings illustrate specific embodiments. However, it is to be understood that these embodiments are not intended to be exhaustive, nor limiting of the disclosure. These specific embodiments are but examples of some of the forms in which the disclosure may be practiced. Like reference numbers or symbols employed across the several figures are employed to refer to like parts or components illustrated therein. [0012] Figure 1 illustrates the test results shown in Table 2 for various quaternary ammonium halides used with carbon steel (C1018).

[0013] Figure 2 illustrates the test results shown in Table 2 for various quaternary ammonium halides used with A387-F11.

[0014] Figure 3 illustrates the test results shown in Table 2 for various quaternary ammonium halides used with A106 GB.

[0015] Figure 4 illustrates the test results shown in Table 3 for El and CE1 used with C1018.

[0016] Figure 5 illustrates the test results shown in Table 3 for El and CE1 used with N80.

[0017] Figure 6 illustrates the test results shown in Table 4 for El and CE1 used with C1018.

[0018] Figure 7 illustrates the test results shown in Table 4 for El and E4 used with C1018.

[0019] Figure 8 illustrates the test results shown in Table 6 for El, CE1, CE5, CE6 and CE7

DETAILED DESCRIPTION

[0020] Disclosed herein are one or more compositions that inhibit the corrosion of a material such as a metal or metallic surface, processes for preparing such compositions, and processes of using of such compositions. Such compositions are effective for inhibiting corrosion of a variety of materials including, but not limited to, carbon and alloy steels such as C1018, A387-F11, A106-GB, N80, and so forth.

[0021] The compositions disclosed herein can be used in any system exposed to fluids (i.e., liquid, gas, slurry, mixtures thereof) that contain a corrosion agent, especially a metal corrosion agent, where improved corrosion inhibition is desired. For example, the compositions disclosed herein can be used for inhibiting corrosion of any metal or metallic surface that is in contact with a concentrated acid solution. However, it should be appreciated that the corrosion inhibitors of this disclosure are particularly well-suited for use in corrosive systems typically encountered in oil and gas operations and refinery operations, for example, an acid treatment in a pipeline for a wellbore or geologic formation. Examples of suitable acids that can be used in acid treatment include, but are not limited to, hydrochloric acid (HCl), hydrofluoric acid (HF), mixtures of HCl and HF (i.e., mud acid which is typically a blend of about 3-12 wt.% HCl and about 1-6 wt.% HF), sulfuric acid (H₂S0₄), hydrobromic acid (HBr), acetic acid, formic acid, other organic acids, and anhydrides. Preferred concentrated acid solutions contain an acid selected from the group consisting of HCl, HF, H₂S0₄, HBr, and mixtures thereof. Preferred concentrated acid solutions include, but are not limited to, acid solutions containing H₂S0₄ in a concentration in the range of from about 3 wt.% to about 70 wt.%, HCl in a concentration in the range from about 3 wt.% to about 37 wt.%, HBr in a concentration in the range from about 3 wt.% to about 62 wt.%, and mixtures of two or more of the foregoing acids.

1. Composition(s)

[0022] As disclosed herein, a composition for inhibiting corrosion of a metal or metallic surface in a concentrated acid solution comprises at least one quaternary ammonium halide. The quaternary ammonium halide comprises a quaternary ammonium cation and a counterion. Providing the quaternary ammonium cation with a long chain alkyl group (e.g., an alkyl group having about 10 to about 24 carbon atoms), can increase the hydrophobicity of the protective film. It was surprisingly found that functionalizing the quaternary ammonium cation, for example, with a halide and/or an alkyl group, provides increased electron density and stability to the quaternary ammonium halide, which may improve adhesion of the quaternary ammonium halide with a metal or metallic surface of a material thereby resulting in the formation of an excellent protective film on the surface of the material.

[0023] It was also surprisingly found that removing a hydrogen from the beta position of the quaternary ammonium cation and adding an alpha alkyl omega aryl group can allow the cation to follow a different degradation pathway, which can improve the chemical stability of the quaternary ammonium halide. Such increased stability can offer improved long term performance of the quaternary ammonium halide. In addition, the alpha alkyl omega aryl group added to the quaternary ammonium cation can be substituted on the ortho, meta, and/ or para positions with a halide, preferably Br, CI, or I, and/ or an alkyl group, preferably a linear alkyl group having about 1 to about 6 carbon atoms.

[0024] The counterion has a charge sufficient to balance the positive charge on the quaternary ammonium cation. The counterion provides the quaternary ammonium halide with increased nucleophilicity, polarizability, and hydrophobicity. Suitable examples of counterions include, for example, at least one halide ion. Br (bromide), CI (chloride), or I (iodide) are preferred counterions because they are generally are more nucleophilic, polarizable and hydrophobic than, for example, F (fluoride). This is because nucleophilicity increases down the periodic table due to the increased polarizability and size of an atom, e.g., (Ί > Br > CI > F). As the size of an atom increases, its outer electrons get further from the attractive force of the nucleus. Thus, the electrons are held less tightly and are said to be more polarizable. The electrons are more freely able to move toward a positive charge, e.g., a metallic or metal surface. More polarizable atoms can form bonds at greater distances. Thus, for example, a Br counterion forms more robust intermediate bridges on a metal surface, which gives rise to stronger bonding or adsorption with the metal, than a less poloarizable counterion such as F.

[0025] The combination of the substituted quaternary ammonium cation and a counterion provides a synergistic effect that improves the overall corrosion inhibition activity of the quaternary ammonium halide. Specifically, the adsorption of the counterion is higher on positively charged surfaces than on negatively charged surfaces while the adsorption of the substituted quaternary ammonium cation is higher on negatively charged surfaces. Thus, the combination of the cationic and anionic effect improves the overall adsorption of the quaternary ammonium halide with the surface of the material.

[0026] In an aspect, the composition comprises one or more quaternary ammonium halides selected from the group consisting Formula (Γ) and Formula (ΙΓ). A quaternary ammonium halide of Formula (I) can be represented by the following general formula:

[0027] The variables in Formula (I) represent the following: R¹ is an alkyl group having about 10 to about 24 carbon atoms, preferably an alkyl group having about 10 to about 20 carbon atoms, more preferably an alkyl group having about 14 to about 18 carbon atoms; R² is an alkyl group having about 1 to about 6 carbon atoms, preferably about 1 to about 4 carbon atoms; R³ is an alkyl group having about 1 to about 6 carbon atoms, preferably about 1 to about 6 carbon atoms; R⁴ is an alpha alkyl omega aryl group, preferably an alpha alkyl omega aryl group substituted with a halide or an alkyl group, more preferably an alpha alkyl omega benzyl group substituted with a halide or an alkyl group; and X is a counterion with a charge sufficient to balance the positive charge on the ammonium compound of Formula I.

Representative counterions include, halides, such as F, CI, Br, I, and combinations thereof; however, Br is a preferred counterion for at least the reasons discussed herein.

[0028] Non-limiting examples of quaternary ammonium halides of Formula (Γ) wherein R⁴ is an alpha alkyl omega aryl group can be represented by the following general structure:

Y = alkyl or halides

n = 1-6

[0029] In the above structure comprising the alpha alkyl omega aryl group, the N atom of the quaternary ammonium halide is bonded at the alpha position of the alkyl group (e.g. alkyl group containing about 1 to about 6 carbon atoms) and an aryl group is bonded to the omega position of alkyl chain. The aryl group may be substituted with Y, wherein Y is an alkyl group or a halide. The position of Y could be ortho-, meta-, and para- on the aryl ring. Below are additional non-limiting examples based on the carbon number (n):

[0030] When n =1,

[0031] When n =2,

[0032] When n =3,

[0034] When n =5,

[0035] When n =6,

[0036] Rep esentative quaternary ammonium halides of Formula (Γ) that can be used in the corrosion inhibiting composition(s) described herein include, but are not limited to, cetyldimethylbenzylammonium bromide, tetradecyldimethylbenzylammonium bromide, octadecyldimethylbenzylammonium bromide, and alkyl dimethylbenzylammonium bromide. Alkyl dimethylbenzylammonium bromide comprises a mixture of

alkyldimethylbenzylammonium bromides, where the number of carbon atoms comprising the alkyl group varies from about 10 to about 18 carbon atoms. In an aspect, the mixture of alkyldimethylbenzylammonium bromides contains about 52 to about 63 wt.% of alkyl groups having about 14 carbon atoms, about 33 to about 52 wt.% of alkyl groups having about 16 carbon atoms, about 7 wt.% of alkyl groups having about 12 carbon atoms, about 7 wt.% of alkyl groups having about 18 carbon atoms, and about 2 wt.% of alkyl groups having about 10 carbon atoms. [0037] Cetyldimethylbenzylammonium bromide, tetradecyldimethylbenzylammonium bromide, and alkyldimethylbenzylammonium bromide can be represented by the following structures respectively:

[0038] Thus, in an aspect, the quaternary ammonium halide of Formula (Γ) is selected from the group consisting of cetyldimethylbenzylammonium bromide,

tetradecyldimethylbenzylammonium bromide, alkyldimethylbenzylammonium bromide, octadecyldimethylbenzylammonium, and mixtures thereof.

[0039] A quaternary ammonium halide of Formula (IT) can be represented the following general formula:

[0040] The variables in Formula (TT) represent the following: A is monocyclic or bicyclic heteroaromatic ring group substituted with a halide or alkyl group, preferably a halide; R⁵ is an alkyl group having about 10 to about 24 carbon atoms, preferably an alkyl having about 10 to about 20 carbon atoms, more preferably an alkyl having about 14 to about 18 carbon atoms; and X² is a counterion with a charge sufficient to balance the positive charge on the parent compound of Formula (II). Representative counterions include those discussed above with respect to Formula (Γ), with Br, CI, or I as preferred counterions for at least the reasons discussed above.

[0041] Representative quaternary ammonium halides of Formula (ΙΓ) that can be used in corrosion inhibiting composition(s) described herein include, but are not limited to, 3- bromocetylpyridinium bromide and 2-methylcetylpyridinium bromide, which can be represented by following structures respectively:

Θ

[0042] Thus, in an aspect, the quaternary ammonium halide of Formula (II) is selected from the group consisting of 3-bromocetylpyridinium bromide, 2-methylcetylpyridinium bromide, and mixtures thereof.

[0043] In quaternary ammonium halides of Formula (II )wherein A is a bicyclic ring, A can be, for example, quinoline or isoquinoline. Such compounds can be represented by following structures:

wherein R is an alkyl, halide or hydro xyl group.

[0044] Additional non-limiting examples of quaternary ammonium halides of Formula (II) include:

alkyl, halides

wherein W is an alkyl group or a halide. 2. Process(es) for Using the Composition(s)

[0045] In an aspect, an effective amount of the corrosion inhibiting composition(s) described herein is added to a concentrated acid solution in contact with a metal or metallic surface. For example, the one or more quaternary ammonium halides as described herein is/are generally present in the composition in an amount in the range of from about 5 ppm to about 50,000 ppm, more preferably about 10 ppm to about 400 ppm, most preferably about 10 ppm to about 100 ppm.

[0046] The composition can further comprise at least one solvent. For example, in oil and gas operations, the composition containing the one or more quaternary ammonium halides is/are typically added to oil, water, and/ or gas fluids in the form of a solution or dispersion in a solvent. Suitable solvents include, but are not limited to, alcohols, hydrocarbons, ketones, ethers, aromatics, amides, nitriles, sulfoxides, esters, aqueous systems, and combinations thereof. The solvent can be water, isopropanol, methanol, ethanol, 2-ethylhexanol, heavy aromatic naphtha, toluene, ethylene glycol, ethylene glycol monobutyl ether (EGMBE), diethylene glycol monoethyl ether, or xylene. Representative polar solvents suitable for formulation with the composition include water, brine, seawater, alcohols (including straight chain or branched aliphatic such as methanol, ethanol, propanol, isopropanol, butanol, 2- ethylhexanol, hexanol, octanol, decanol, 2-butoxyethanol, etc.), glycols and derivatives (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, ethylene glycol monobutyl ether, etc.), ketones (cyclohexanone, diisobutylketone), N-methylpyrrolidinone (NMP), N,N- dimethylformamide, and so forth. Representative non-polar solvents suitable for formulation with the composition include aliphatic hydrocarbons such as pentane, hexane, cyclohexane, methylcyclohexane, heptane, decane, dodecane, diesel, and so forth; aromatic hydrocarbons such as toluene, xylene, heavy aromatic naphtha; and fatty acid derivatives (acids, esters, amides), and so forth.

[0047] The composition can further comprise additional components commonly used in acidizing fluids, for example, solvents as described above (e.g., alkyl alcohol and glycol), surfactants (i.e., dispersing agents), chelating/ sequestering agents, wetting agents, friction reducers, scale inhibitors, carbon dioxide control additives, paraffin control additives, oxygen control additives, salt inhibitors, iron control agents, non-emulsifiers, foaming agents, bactericides, hardening agents, solubility modifiers, defoamers, sulfide scavenger, anti- redeposition agents, clay stabilizer, or fluid loss control agents. Other additive ingredients may vary depending upon the type of composition being manufactured and applications. These additives are optional and can be added in an effective amount based on the application.

[0048] The compositions can be applied to a fluid or gas in any selected concentration depending on the type of corrosive system. That is, each corrosive system can have its own requirements, and the effective amount of a composition to sufficiently reduce the rate of corrosion can vary with the system in which it is used. Thus, in an aspect, the composition(s) of this disclosure are added to the concentrated acid solution in contact with the metal or metallic surface to provide an effective treating dose. For example, the one or more quaternary ammonium halides in the composition(s) is/are present in the corrosive system in a concentration in the range from about 5 to about 50,000 ppm, more preferably about 10 to about 400 ppm, most preferably about 10 to about 100 ppm.

[0049] Surprisingly, several of the compositions of the present disclosure exhibited similar or in some cases superior corrosion inhibiting activity than the other corrosion inhibiting composition even when present in lower concentrations, for example, El vs. CE1 as shown in Figs. 4-6. Utilizing a smaller dose of a corrosion inhibitor that offers a similar or better corrosion protection performance is of particular advantage because it is environmentally friendly (i.e., less corrosion inhibitor is required) in addition to gaining a benefit of cost reduction. It also reduces the effort to remove the corrosion inhibitor after its usage, thus it makes recycling of acid solutions easier.

[0050] A fluid treated with a composition of the invention can be at any selected

temperature, such as ambient temperature or an elevated temperature. For example, the fluid (e.g., acidic aqueous solution) can be at a temperature in the range from about 25 °C to about 100 °C, more preferably about 40 °C to about 90 °C, most preferably about 60 °C to about 80 °C.

[0051] The composition may be introduced to the concentrated acid solution in contact with the metal or metallic surface in accordance with techniques well-known to those skilled in the art that ensure dispersal of the composition through the fluid. For example, the

composition(s) can be added at a point in a flow line upstream from the point at which corrosion prevention is desired. The composition(s) can be injected or pumped into a flow line using mechanical equipment such as chemical injection pumps, piping tees, injection fittings, atomizers, quills, and so forth. The composition(s) of the invention can be introduced with or without one or more of the solvents and/ or additional components described above depending upon the application and requirements.

3. Process(es) for Preparing the One or More Quaternary Ammonium Halides

[0052] The one or more quaternary ammonium halides described herein are generally prepared using reactions in an aqueous system starting from an alcohol such as an aryl or alkyl alcohol, preferably an aryl alcohol. The alcohol is combined with an inorganic halide acid, such as a concentrated aqueous strong acid, to form an intermediate halide product mixture comprising one or more halides (e.g., alkyl halide or aryl halide), preferably an aryl halide. The intermediate halide product mixture is combined an amine, preferably a tertiary amine thereby producing a mixture of one or more quaternary ammonium halides as described above.

[0053] Suitable alcohols include, but are not limited to, having alkyl substituents with about 1 to about 10 carbon atoms such as a linear or branched alkyl, benzyl, cycloalkyl, alkyl ether, and alkyl ester. Suitable inorganic halide acids include, but are not limited to, hydrogen halides such as HI (hydrogen iodide), HBr (hydrogen bromide), HC1 (hydrogen chloride), and HF (hydrogen fluoride), and combinations thereof, with aqueous HBr as a preferred inorganic halide acid. The concentration of the inorganic halide acid may vary depending upon the reaction conditions. Although any inorganic halide acid concentration may be used, in general a higher concentration of inorganic halide acid may shorten the reaction time. For example, to speed up the reaction, HBr acid concentration of greater than about 33 wt.% is preferred and more preferably 62 wt%.

[0054] The amine is preferably a tertiary amine having alkyl or aryl substituents with about 1 to about 24 carbon atoms. Examples of suitable alkyl substituents include, but are not limited to, cycloalky, heterocyclic, hydroxyl alkyl, hydroxyl cycloalkyl, alkyl ether, alkyl ester, alkyl thioester, alkenyl, and alkynyl. Aryl substituents can be a monocyclic, bicyclic, or tricyclic aromatic, for example, phenyl, benzyl, and heteroaryl (e.g. pyridine, imidazole). In an aspect, one substituent of the tertiary amine is preferably an alkyl having about 12 to about 20 carbon atoms.

[0055] The one or more quaternary ammonium halides prepared in accordance with this disclosure may be more environmentally friendly than other processes well-known by those of ordinary skill in the art. For example, little to no hazardous byproduct is produced and no organic solvent is required throughout the entire process. Only water and nontoxic inorganic salt with desired quaternary ammonium halide can typically be produced, which may offer the reduced cost of hazardous waste treatment. The entire process can be conducted in water as a solvent, and if necessary, polar solvents such as alcohols (e.g., ethanol) may be used as a solvent.

[0056] Of course, although the one or more quaternary ammonium halides are preferably prepared as described above, it should be appreciated that the compositions described herein can be prepared in accordance with other techniques well-known to those skilled in the art. For example, typically, PBr₃ (phosphorous tribromide) has been applied to transform alkyl alcohol to alkyl halide. However, this reaction generally requires a low temperature (below 0 °C) and usually provides a lower yield, and can generate phosphorous acid as a byproduct, which should be removed for the next reaction.

4. Examples

[0057] The present disclosure can be better understood by reference to the following examples, which are presented for purposes of illustration and are not intended to limit the scope of the invention.

4.1 Examples Evaluating Corrosion Performance [0058] Corrosion studies were conducted either based on the following procedures: (1) ASTM G31 - 72 (Reapproved 2004): Standard Practice for Laboratory Immersion Corrosion Testing of Metals; or (2) the test protocol described below.

[0059] Weight loss experiments were performed with different metal coupons that were fully immersed in a solution in a commercial heavy duty borosilicate glass bottle with autoclavable polypropylene caps. Solutions were prepared by dilution of commercial reagent grade acid with distilled water. Typically, 200 mL of treatment fluid was used, to which was added the selected amount of corrosion inhibitor composition(s) given in parts per million

concentrations (ppm). The selected test metal coupons were added to the inhibited acid solutions and these solutions were placed in an oven at the desired elevated temperature. The coupons remained in the oven for the test duration, typically in the range from one hour to 28 days depending on the test conditions. Metal coupons were carefully weighed before and after the tests. After the test, coupons were removed from the reaction vessels, cleaned and weighed to obtain their weight loss. The corrosion value was given in mils per year (mpy).

[0060] For comparative purposes, corrosion inhibitor compositions containing quaternary ammonium halides such as cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, cetylpyridinium bromide, and cetylbenzyldimethylammonium chloride were also tested following the above described procedures. In addition, propargyl alcohol, butyne diol, and triethanolamine were tested as comparative examples. These compounds were selected as representative examples of different categories of corrosion inhibitors. Propargyl alcohol and butyne diol are examples of acetylenic alcohol and acetylenic diol, which showed excellent performance in many applications such as oilfield acidification and steel acid pickling.

Triethanolamine has been also known as one of the commonly used amine type corrosion inhibitors. The quaternary ammonium halides and few other commonly used corrosion inhibitors utilized in the tests are summarized in Table 1 below. The results of the tests using quaternary ammonium halides are set forth in Table 2 below, and also illustrated in the appended figures.

CE2 cetyltrimemylammonium chloride

CE3 cetylpyridinium bromide

CE4 cetylbenzyldimethylammonium chloride

CE5 propargyl alcohol

CE6 butyne diol

CE7 triethanolamine

Test Conditions for Table 2: 400 ppm of corrosion inhibitor loading; 3 wt.% HCl, 60 °C; and 28 days.

[0061] As shown in the Table 2 and the Figs. 1-3, the results indicate that compositions of the present disclosure (E1-E3) generally exhibit superior corrosion inhibiting activity than the compositions of the comparative examples (CE1-CE3). For example, El exhibits superior corrosion resistance compared to CE1 and CE2, and E2 exhibits superior corrosion resistance compared to CE3. The superior performance of compounds of this disclosure is surprising and believed, at least in part, to be due to functionalizing the quaternary ammonium cation, which can provide increased electron density and stability to the compound thereby improving adhesion with a metal or metallic surface of a material and resulting in the formation of an excellent protective film on the surface of the material. In addition, surprisingly, some the compositions of the present disclosure exhibited similar or in some cases superior corrosion inhibiting activity than the compositions of the comparative examples even when present in lower concentrations, for example, El vs. CE1 as shown in Figs. 4-6. [0062] In order to evaluate the efficiency of quaternary ammonium bromide as corrosion inhibitors in different acidity, 1-12 M (mol/L) concentrations of HCl was tested in the presence of El, and compared to test results for CEl under the same test conditions. Mild carbon steel (C1018) and oilfield pipeline metal alloy (NT 80) were tested under the sample condition (500 ppm of corrosion inhibitor loading, 60 °C, and 3-24 hours of metal coupon immersion time depending on the acid concentration). As shown in the Table 3 and Figs. 4 and 5, El consistently showed the superior corrosion results under all HCl concentrations

[0063] Reducing corrosion inhibitor loading concentration is one essential part of research areas because it is a huge advantage to use a smaller dose of corrosion inhibitor that offers a similar or better corrosion protection performance. It is environmentally friendly in addition to gaining a benefit of cost reduction. It also reduces the effort to remove the corrosion inhibitor after its usage, thus it makes recycling of acid solutions easier. Concentration dependence of corrosion inhibitor El was carefully monitored in about 10 wt.% HCl solutions at 60 °C for 24 hours with carbon steel C1018. 50-1000 ppm of El was tested compared with CEl and results were shown below in Table 4 and Figure 6.

50 82 95 N/A N/A 733

100 80 92 N/A N/A 553

200 72 96 N/A N/A 480

250 100 N/A N/A N/A 527

300 80 97 N/A N/A 449

400 74 64 N/A N/A 480

500 84 98 115 112 509

1000 91 102 N/A N/A 519

* Test conditions for Table 4: 10 wt.% HC1; at 60 °C; for 24 hours

[0064] Figure 6 illustrates the increasing trend of corrosion rates as concentrations of corrosion inhibitor CE1 decreased from 1000 ppm to 50 ppm while El showed consistent corrosion rates under all corrosion inhibitor concentrations. It is worth emphasizing that even with 10 times higher corrosion inhibitor loading of CE1, El performed better under the same corrosive environment. For example, a concentration of 1000 ppm of CE1 exhibited a corrosion rate of 519 mpy whereas the corrosion rate was 91 mpy for a concentration 50 ppm of El.

[0065] Based upon these encouraging results, two additional alkylbenzyldimethylammonium bromides such as E4 and E5 were prepared from ALBEMARLE® commercial products, ADMA-14 and ADMA-1416, similar as El prepared from ALBEMARLE® ADMA-16. ADMA-16, ADMA-14, and ADMA-1416 are N, N-dimethyl-l-hexadecaneamine, N, N- dimethyl-l-tetradecaneamine, and N, N-dimethyl-l-alkylamine (mixture of C₁₀-C₁₈), respectively. Table 4 and Figure 7 showed that E4 followed the similar pattern as El with about 10 % increase of corrosion rates as compared to El.

[0066] A weight loss corrosion experiment of E5 synthesized from ADMA-1416® was also conducted compared with El and E4. Since 84 wt% active ingredient of E5 includes 2:1 ratio of E4 and El, a mixture of E4 and El (2:1 ratio) was prepared to compare with E5. In the presence of 500 ppm of corrosion inhibitors, the corrosion rate results of E5 showed about 15% and 25 % increases from E4 and El, respectively. However, a 2:1 mixture of El and E4 has a comparable corrosion rate as E5. (Table 4). These results indicates that the generic structure of quaternary ammonium halides also plays a critical role on the corrosion protection efficacy as well as hydrophobic alkyl chain lengths, which provide the protection layer on the metal surface.

[0067] The beneficial effect of bromo-functionalization on cetylpyridinium bromide, E2, was further evaluated with increased HC1 acidity (1-6 M) and temperature (60-90 °C) as shown in Table 5. It is believed that bromo-substituted pyridinium cation could offer the higher hydrophobicity due to the hydrophobic character of Br. The weight loss experiment was conducted either with carbon steel C1018 or N80. The results clearly revealed that corrosion rates of E2 were improved (about 50% reduction in corrosion rates) under all tested conditions with both N80 and C1018 compared with CE3.

[0068] It was surprising that quaternary ammonium bromides bring the improved corrosion efficiency to the system compared with chloride counterparts. Cationic structures of both El and CE4 are identical and only difference between these two is counter anions. More polarizable bromine atoms can form bonds at greater distances, so that bromide anions on the metal surface form the more robust intermediate bridges, which gives rise to stronger bonding; in this case, stronger absorption onto the metal. A weight loss experiment was conducted with carbon steel C1018 at 60 °C in various concentration of HC1 solutions (1- 12M) and immersion time was varied depending on the HC1 acidity. A comparison of El and CE4 in Table 5 indicates that about 50 % reduction on corrosion rates for all acidity was observed from El with bromide anion. [0069] Test results of El compared with CEl, CE5, CE6, and CE7 with different corrosion inhibitor loading in a range of 5 ppm to 50,000 ppm are shown in Table 6. Corrosion tests were conducted at ambient temperature (~23°C) in 15 % HC1 solution by using mild carbon steel (C1018). This testing condition was selected to demonstrate a typical acid pickling bath in Steel and Iron industry. The weight loss experiment results showed that CE5 performed better with corrosion inhibitor loading higher than about 1,000 ppm. However, El and CE5 displayed similar corrosion rate at concentration of about 1,000 ppm and the corrosion rate of El was better with corrosion inhibitor loading lower than about 1,000 ppm. El showed constant or substantially constant performance even at about 10 ppm loading while CE5 slowly lost its efficiency as corrosion inhibitor concentration decreased. Propargyl alcohol is a commonly accepted standard corrosion inhibitor for acidification, but it produces toxic vapors during the acidification process and it is difficult to store/handle due to its highly flammable character. Unlike propargyl alcohol, El generates no toxic byproducts during the acidification process and it offers high thermal/chemical stability. Another example of acetylenic alcohol, CE 6, as well as amine type corrosion inhibitor, CE7, and simple quaternary ammonium bromide, CEl, showed poor corrosion inhibition efficiency compared to El. (Figure 8) In order to achieve the similar metal surface protection performance as El, CE6 requires about 5000 times more CI loading. Furthermore, CE7 could not achieve the such high performance even with about 5000 times more CI loading.

10 C1018 15 202

5 C1018 15 224

50,000 C1018 15 162

5,000 C1018 15 253

1,000 C1018 15 265

CE7 500 C1018 15 260

100 C1018 15 248

10 C1018 15 297

5 C1018 15 287

50,000 C1018 15 123

5,000 C1018 15 132

1,000 C1018 15 124

CEl 500 C1018 15 134

100 C1018 15 134

10 C1018 15 206

5 C1018 15 221

* Test Conditions for Table 6: 15 wt.% HC1, at ambient temperature (23 °C), for 1 hour.

4.2 Examples of Preparing Quaternary Ammonium Halides

[0070] Quaternary ammonium halides were prepared by the following synthetic procedures. Alkyl alcohol was heated with concentrated aqueous HBr to generate alkyl bromide. A tertiary amine was further reacted with alkyl bromide to obtain the desired quaternary ammonium halides. The entire process was conducted in water as solvent, substantially only H₂0 was generated as a byproduct, and unreacted reagent can be easily recycled for the next batch.

4.2.1 Preparation of Alkylbenzyldimethylammonium Bromide

[0071] Alkylbenzyldimethylammonium bromide was prepared as described below. A round- bottom flask equipped with a condenser was charged with benzyl alcohol (1 eq) and aqueous HBr solution (1-1.5 eq). This mixture was agitated (temperature may vary from room temperature (e.g., about 22 °C to about 150 °C) to generate benzyl bromide until completing the conversion. Benzyl bromide was further reacted with alkyldimethylamine and then the reaction mixture was heated in water (0-80 wt. %) at about 60-150 °C for about 1-6 hours. The resulting mixture was cooled down to about 0-25 °C until white precipitate formed. The white solid was collected by filtration and then dried.

[0072] For the first step, a concentrated aqueous HBr (33-62% in water, if necessary anhydrous gas HBr is used) was added to benzyl alcohol without additional solvent to generate benzyl bromide. Alkyldimethyl amine was reacted with benzyl bromide to obtain desired ammonium bromide with or without additional water. [0073] The reaction to prepare benzyl bromide may be stirred at room temperature (e.g., about 22 °C), or heated at any temperature below about 150 °C. When anhydrous HBr gas was used, external heat may not be needed due to the exothermic nature of reaction. The period of time may be from about 0.5 to about 6 hours. This reaction may last for any period of time until it is determined that a sufficient amount of benzyl bromide has formed.

[0074] The ratio between each reactant to synthesize benzyl bromide may vary based on the reaction conditions. In order to maximize the conversion of benzyl bromide, excess amount (1-2 eq.) of HBr, highly concentrated aqueous HBr (62% or higher), or anhydrous HBr (gas) may be required, which could be easily collected after reaction by a simple extraction of aqueous layer and recycled for the next batch. If necessary, benzyl bromide could be purified by distillation to remove water after the reaction and this purified benzyl bromide was further reacted with alkyldimethyl amine in water.

[0075] Preferably, alkyldimethyl amine compounds used for this process are

ALBEMARLE® commercial products with different alkyl chain length, (e.g. ADMA-14, ADMA-16, ADMA-1416) ADMA-14 (Ν,Ν-dimethyl l-tetradecaneamme, CAS-No: 112-75-4) and ADMA-16 ( ,Ν-dimethyl 1-hexadecaneamine, CAS-No: 112-69-6) include more than 98 wt.% pure desired alkyldimethyl amines. ADMA-1416 contains 52-63 wt.% of C14 ( ,N- dimethyl l-tetradecaneamme, CAS-No: 112-75-4), 33-52 wt.% of C16 (Ν,Ν-dimethyl 1- hexadecaneamine, CAS-No: 112-69-6),7 wt.% of C12 (Ν,Ν-dimethyl 1-dodecaneamine, CAS- No: 112-18-5), higher than 7 wt.% of C18 ( ,Ν-dimethyl 1-octadecaneamine, CAS-No: 124- 28-7), and 2 wt.% of CIO ( ,Ν-dimethyl -1-decaneamme, CAS-No: 1120-24-7).

[0076] Alkyldimethyl amine was reacted with benzyl bromide with a vigorous agitation at elevated temperature, e.g. a temperature in the range from about 22 °C to about 150 °C. The period of time may be from about 0.5 hour to about 6 hours. This reaction may last for any period of time until it is determined that a sufficient amount of quaternary ammonium bromide has formed.

[0077] If it is needed after reaction stopped, water may be added to the resulting reaction mixture and it was cooled down to about 0-25 °C until white solid formed. This white solid may be washed with water, collected, and dried.

4.2.2 Preparation of Benzylcetyldimethylammonium Bromide A I L 3-necked round bottom flask was charged with benzyl alcohol (245.5 g, 2.27 mol, 1.0 eq) a condenser and thermocouple were attached to the flask and temperature was monitored. At 90 °C, HBr (62% in water, 275.9g, 1.5 eq) was slowly added to generate benzyl bromide. After 90 minutes of agitation, aqueous layer was removed by a simple extraction and 30 % (-200 g)of total volume of ADMA-16 ( ,N-dimethylcetylamme, 611.8 g, 2.27 mol, 1.0 eq) was slowly added to benzyl bromide with a vigorous agitation. This mixture was heated for 15 more minutes and then rest of ADMA-16 (—412 g) and 0.8 L of water were co-feeded. This resulting mixture was continuously heated at 90°C for 1 hour with vigorous agitation and cooled down to room temperature (~ 23°C) until white solid formed. The resulting solid was filtered and dried to obtain the white solid product.

4.3 Toxicology Studies

[0078] Quantitative Structure— Activity Relationship (QSAR) computational modeling was conducted to evaluate the toxicity of quaternary ammonium bromide by using octanol-water partition coefficient (Log P) and bioconcentration factor (BCF). Log P value is used as a measure of molecular hydrophobicity and the value higher than 5 and smaller than 8 was considered as highly bioaccumulative. Based on the calculation results, introduction of benzyl group increases the hydrophobicity of quaternary ammonium bromide, however, El was not still considered as highly bioaccumulative. Bromo-substituted quaternary ammonium, E2, also showed the very small increases of the Log P value. BCF shows a steady-state distribution of chemical between aquatic organism and water. Both The Toxic Substances Control Act (TSCA) and the European Union's Regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) recommend that BCF value of the smaller than 5000 L/kg is highly bioaccumulative. All of calculated quaternary ammonium bromides showed low BCF values. These calculated toxicology results suggest that the increased hydrophobicity of quaternary ammonium bromides delivers a small impact on toxicity while it dramatically improves corrosion efficiency.

[0079] Components referred to by chemical name or formula anywhere in the specification or claims hereof, whether referred to in the singular or plural, are identified as they exist prior to coming into contact with another substance referred to by chemical name or chemical type (e.g., another component, a solvent, or etc.). It matters not what chemical changes, transformations and/or reactions, if any, take place in the resulting mixture or solution as such changes, transformations, and/or reactions are the natural result of bringing the specified components together under the conditions called for pursuant to this disclosure. Thus, the components are identified as ingredients to be brought together in connection with performing a desired operation or in forming a desired composition.

[0080] It should be recognized that unless stated otherwise, it is intended that endpoints are to be interchangeable. Further, any ranges include iterative ranges of like magnitude falling within the expressly stated ranges or limitations disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. It is to be noted that the terms "range" and "ranging" as used herein generally refer to a value within a specified range and encompasses all values within that entire specified range.

[0081] As used herein, the term "about" modifying the quantity of an ingredient in the compositions of the invention or employed in the methods of the invention refers to variation in the numerical quantity that can occur, for example, through typical measuring and liquid handling procedures used for making concentrates or use solutions in the real world; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods; and the like. The term "about" also encompasses amounts that differ due to different equilibrium conditions for a composition resulting from a particular initial mixture. Whether or not modified by the term "about", the claims include equivalents to the quantities.

[0082] Also, even though the claims hereinafter may refer to substances, components and/ or ingredients in the present tense ("comprises", "is", etc.), the reference is to the substance, component or ingredient as it existed at the time just before it was first contacted, blended or mixed with one or more other substances, components and/or ingredients in accordance with the present disclosure. The fact that a substance, component or ingredient may have lost its original identity through a chemical reaction or transformation during the course of contacting, blending or mixing operations, if conducted in accordance with this disclosure and with ordinary skill of a chemist, is thus of no practical concern. [0083] Except as may be expressly otherwise indicated, the article "a" or "an" if and as used herein is not intended to limit, and should not be construed as limiting, a claim to a single element to which the article refers. Rather, the article "a" or "an" if and as used herein is intended to cover one or more such elements, unless the text taken in context clearly indicates otherwise.

[0084] Each and every patent or other publication or published document referred to in any portion of this specification is incorporated as a whole into this disclosure by reference, as if fully set forth herein.

[0085] This invention is susceptible to considerable variation in its practice. Therefore the foregoing description is not intended to limit, and should not be construed as limiting, the invention to the particular exemplifications presented hereinabove.

Claims

CLAIMS What is claimed is:

1. A composition comprising one or more quaternary ammonium halides selected from the group consisting of:

wherein

R¹ is an alkyl group having about 10 to about 20 carbon atoms;

R² is an alkyl group having about 1 to about 4 carbon atoms;

R³ is an alkyl group having about 1 to about 4 carbon atoms;

R⁴ is an alpha alkyl omega aryl group;

X¹ is Br; and

wherein

A is monocyclic or bicyclic heteroaromatic ring group substituted with a halide;

R⁵ is an alkyl group having about 10 to about 20 carbon atoms; X² is Br, CI, or I; and wherein the composition is suitable for inhibiting corrosion of a metal or metallic surface that is in contact with a concentrated acid solution.

2. The composition of claim 1 wherein the alpha alkyl omega aryl group is substituted with a halide or an alkyl group.

3. The composition of claim 1 the alpha alkyl omega aryl group is an alpha alkyl omega benzyl group substituted with a halide or an alkyl group.

4. The composition of claim 1 wherein R¹ is an alkyl group having about 14 to about 18 carbon atoms.

5. The composition of claim 1 wherein the quaternary ammonium halide (I) is selected from the group consisting of cetyldimethylbenzylammonium bromide,

tetradecyldimethylbenzylammonium bromide, octadecyldimethylbenzylammonium bromide, a mixture of alkyl dimethylbenzylammonium bromides wherein the number of carbon atoms comprising the alkyl group is from about 10 to about 18 carbon atoms, and mixtures thereof.

6. The composition of claim 1 wherein R⁵ is an alkyl group having about 14 to about 18 carbon atoms.

7. The composition of claim 1 wherein the quaternary ammonium halide (IT) is 3- bromocetylpyridinium bromide.

8. A process comprising: adding a composition to a concentrated acid solution in contact with a metal or metallic surface thereby inhibiting corrosion of the metal or metallic surface, the composition comprising one or more quaternary ammonium halides selected from the group consisting of:

wherein

R¹ is an alkyl having about 10 to about 20 carbon atoms;

R² is an alkyl group having about 1 to about 4 carbon atoms;

R³ is an alkyl group having about 1 to about 4 carbon atoms;

R⁴ is an alpha alkyl omega aryl group; X¹ is Br; and

wherein

R⁵ is an alkyl group having about 10 to about 20 carbon atoms; X² is Br, CI, or I.

9. The process of claim 8 wherein the alpha alkyl omega aryl group is substituted with a halide or an alkyl group.

10. The process of claim 8 wherein the alpha alkyl omega aryl group is an alpha alkyl omega benzyl group substituted with a halide or an alkyl group.

11. The process of claim 8 wherein R¹ is an alkyl group having about 14 to about 18 carbon atoms.

12. The process of claim 8 wherein the quaternary ammonium halide (Γ) is selected from the group consisting of cetyldimethylbenzylammonium bromide,

tetradecyldimethylbenzylammonium bromide, octadecyldimethylbenzylammonium bromide, a mixture of alkyl dimethylbenzylammonium bromides comprising a mixture of C₁₀-C₁₈ alkyls, and mixtures thereof.

13. The process of claim 8 wherein R⁵ is an alkyl group having about 14 to about 18 carbon atoms.

14. The process of claim 8 wherein the quaternary ammonium halide (ΙΓ) is 3- bromocetylpyridinium bromide.

15. The process of claim 8 wherein the one or more quaternary ammonium halides is/are present in the composition in a concentration in the range of from about 5 ppm to about 50,000 ppm.

16. The process of claim 8 wherein the one or more quaternary ammonium halides is/are present in the composition in a concentration in the range of from about 10 ppm to about 100 ppm.

17. The process of claim 8 wherein the concentrated acid solution comprises an acid selected from the group consisting of hydrochloric acid (HCl), hydrofluoric acid (HF), sulfuric acid (H₂S0₄), hydrodbromic acid (HBr), and mixtures thereof.

18. The process of claim 8 wherein the concentrated acid solution is H₂S0₄, and the acid is present in a concentration in the range from about 3 wt.% to about 70 wt.%.

19. The process of claim 8 wherein the concentrated acid solution is HCl, and the acid is present in a concentration in the range from about 3 wt.% to about 37 wt.%.

20. The process of claim 8 wherein the concentrated acid solution is HBr, and the acid is present in a concentration in the range from about 3 wt.% to about 62 wt.%.

21. A process comprising: combining an aryl alcohol with an inorganic halide acid to form an intermediate halide product mixture; combining the intermediate halide product mixture with a tertiary amine; thereby producing a mixture of one or more quaternary ammonium halides selected from the group consisting of:

wherein

R¹ is an alkyl having about 10 to about 20 carbon atoms;

R² is an alkyl group having about 1 to about 4 carbon atoms;

R³ is an alkyl group having about 1 to about 4 carbon atoms;

R⁴ is an alpha alkyl omega aryl group;

X¹ is Br; and

wherein

R⁵ is an alkyl group having about 10 to about 20 carbon atoms; and

X² is Br, CI, or I.

22. The process of claim 21 wherein the alpha alkyl omega aryl group is substituted with a halide or an alkyl group.

23. The process of claim 21 wherein the alpha alkyl omega aryl group is an alpha alkyl omega benzyl group substituted with a halide or an alkyl group.

24. The process of claim 21 wherein R¹ is an alkyl group having about 14 to about 18 carbon atoms.

25. The process of claim 21 wherein Formula I is selected from the group consisting of cetyldimethylb enzylammonium b romide, tetradecyldimethylb enzylammonium bromide, octadecyldimethylbenzylammonium bromide, a mixture of

alkyldimethylb enzylammonium bromides comprising a mixture of C₁₀-C₁₈ alkyls, and mixtures thereof.

26. The process of claim 21 wherein R⁵ is an alkyl group having about 14 to about 18 carbon atoms.

27. The process of claim 21 wherein the quaternary ammonium halide (ΙΓ) is 3- bromocetylpyridinium bromide.

28. The process of claim 21 wherein the inorganic halide acid is HBr.