NO871926L - PROCEDURE FOR AA PREVENTING ATTACK OF CORROSIVE FLUIDS POWDER METALS, AND PREPARATION FOR CARRYING OUT THE PROCEDURE. - Google Patents

Description

The invention relates to new corrosion-inhibiting preparations

ters and procedures for their application. More particularly, the invention relates to new corrosion-inhibiting preparations which reduce the attack of various aqueous fluids, including aqueous acids, alkaline solutions and strong brines, on ferrous metals, for example iron and steel, as well as methods for using such preparations.

Aqueous acids, alkaline solutions and strong brines are known to destroy ferrous metal surfaces. These corrosive substances are often found in, or added to, crude oils and intermediates or end products made from these. In addition, when searching for and extracting petroleum from underground fields, it is common to "acidize" new and producing wells with aqueous solutions of strong acids. This can naturally lead to corrosion of well liners, pumps and other equipment containing ferrous metal.

Likewise, acidic materials are often developed in equipment used in processing or transporting petroleum refinery streams, where water vapor can combine with acidic gases developed during refining operations and produce corrosive gases.

Various materials for inhibiting the attack of corrosive fluids on ferrous metals are known, but few provide satisfactory protection. For example, arsenic and various arsenic compounds have been used, despite their toxicity, as acid corrosion inhibitors for ferrous metals. However, the deleterious effect that arsenic and arsenic compounds have on catalysts used in petroleum refineries, coupled with their toxicity, has led the industry to search for corrosion inhibitors free of such undesirable properties.

US Patent No. 3,077,454 discloses inhibitors of aqueous acid attack on metals comprising certain active nitrogen-containing compounds, such as primary and secondary amines, mixed with ketones and aliphatic or aromatic aldehydes.

US Patent Nos. 3,530,059, 3,537,974 and 3,589,860 all disclose the use of aldehydes to prevent corrosion of metals, such as steel, by aqueous acid solutions. Aralkyl aldehydes where the aldehyde group is attached to the aliphatic side chain are the corrosion inhibiting aldehydes disclosed in US Patent 3,530,059. US Patent 3,537,974 discloses alkoxy substituted benzaldehydes, for example p-methoxybenzaldehyde, as corrosion inhibitors, while US Patent 3,589 860 discloses the use of cinnamaldehyde (ie cinnamaldehyde), as well as certain derivatives thereof for this purpose.

US Patent No. 3,854,959 discloses mixtures of a nitrile or an oxime with aldehydes as corrosion inhibitors for steel.

A paper by Hugel entitled "Corrosion Inhibitors, Study of Their Active Mechanism", delivered at the Tenth Meeting of the European Corrosion Federation, Ferrara, Italy, September 28 to October 1, 1960, reveals that a number of aldehydes have been tested for corrosion inhibition (see for example Table I) .

An article by Derarajan et al entitled "Aldehydes as Inhibitors for Mild Steel Corrosion in Acids", Trans. SAEST, 19, 1, 71-81 (1984) states (on page 75) that "in acid solutions, cinnamaldehyde has been found to show the highest effectiveness in reducing corrosion".

A paper by Rocchini entitled "A study concerning acid cleaning of a 'steam generator carried out with a pilot plant - Part I'" held at CORROSION '85, Boston, Massachusetts, March 25-29, 1985, states on page 188/7 that a commercial inhibitor, BORG p 16, is derived from Rodine 213, with the addition of cinnamic aldehyde to improve its heat stability.

Fedorov et al., Zashch. Metal., 1971, 7(1), 73-6, CA 74, 82362J, discloses that certain organic thiocyanates and indole derivatives which behave as surfactants have a corrosion-inhibiting effect on steel in acid solutions.

US Patent No. 4,493,775 discloses corrosion inhibiting compositions in which formaldehyde is both a reactant and an unreacted component (present in excess). These compositions may, but need not, also contain a surfactant.

Co-pending US Patent Application No. 06/765,890, filed Aug. 14, 1985 by W. Frenier, V.R. Lopp, F. Growcock and B. Dixon, discloses and claims protection for the inhibition of corrosion of iron and steel in contact with aqueous acids, using compositions containing an alkenylphenone derivative and which may contain, but need not contain, a surfactant means too.

It has now been discovered that certain aldehydes, in combination with a surface-active agent, provide corrosion-inhibiting compositions which reduce the attack of various aqueous fluids, such as aqueous acids, alkaline solutions and strong brines, on ferrous metals, such as iron and steel, as well as on non -ferrous metals, such as aluminium, zinc and copper. Surprisingly, such corrosion inhibiting preparations containing aldehyde and surfactant provide greater and more reliable corrosion inhibition than preparations containing the aldehydes alone.

It is therefore an object of the present invention to provide improved preparations for inhibiting metal corrosion caused by corrosive aqueous fluids.

Another object of the invention is to provide improved preparations for inhibiting ferrous metal corrosion caused by corrosive aqueous fluids, these corrosion-inhibiting preparations comprising certain aldehydes and a surfactant.

It is also an object of the invention to provide an improved method for inhibiting ferrous metal corrosion caused by corrosive aqueous fluids.

A further object of the invention is to provide

an improved method for inhibiting ferrous metal corrosion caused by aqueous fluids, which comprises mixing certain aldehydes and a surfactant with such corrosive aqueous fluids.

These and other purposes, as well as the nature, scope and application of the invention, will be easily understood by those skilled in the art from the following description and the accompanying claims.

The aldehydes

The aldehydes used in the new corrosion-inhibiting preparations according to the present invention are a,ø-unsaturated aldehydes with the general formula:

where: is a saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to approx. 12 carbon atoms, a substituted saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to approx. 12 carbon atoms and which also contains one or more non-interfering substituents, an aryl group,

for example phenyl, benzyl or the like, a substituted aryl group containing one or more non-interfering substituents, or a non-interfering substituent as such,

R 2 is hydrogen, a saturated or unsaturated aliphatic hydrocarbon group containing from 1 to about 5 carbon atoms, a substituted saturated aliphatic hydrocarbon group containing from 1 to about 5 carbon atoms and also contains one or more non-interfering substituents, an aryl group, a substituted aryl group containing one or more non-interfering substituents, or a non-interfering substituent as such, and

R^ is hydrogen, a saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to approx. 12 carbon atoms, a substituted saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3" to about 12 carbon atoms and which also contains one or more non-interfering substituents, an aryl group, a substituted aryl group containing one or more non-interfering substituents, or a non-interfering substituent as such,

with the total number of carbon atoms in substituents represented by R , R 2 and R 2 varying from 1 to approx. 16, preferably from approx. 5 to approx. 10.

Non-interfering substituents referred to above which replace hydrogen on the α- and 3-carbon atoms of the aldehydes of formula I above or which are present in hydrocarbon substituents which replace hydrogen on these carbon atoms and have no adverse effect on the corrosion inhibition are provided by the new preparations in according to the invention. They include, for example, lower alkyl (containing from 1 to about 4 carbon atoms), lower alkoxy (containing from 1 to about 4 carbon atoms), halogen, i.e. fluorine, chlorine, bromine or iodine, hydroxyl, dialkyl-amino, cyano, thiocyano, N,N-dialkylcarbamoylthio and nitro as substituents.

Included among the α,$-unsaturated aldehydes represented by formula I above are: crotonaldehyde, 2-hexenal,

2-heptenal,

2-octenal,

2-nonenal,

2-decade,

2-undecenal, 2-dodecenal, 2,4-hexadienal, 2,4-heptadienal, 2,4-octadienal, 2,4-nonadienal, 2,4-decadienal, 2,4-undecadienal, 2,4-dodecadienal, 2,6-dodecadienal, citral,

1-formyl-[2-(2-raethylvinyl)]-2-n-octylethylene, cinnamaldehyde, dicinnamaldehyde, p-hydroxycinnamaldehyde, p-methylcinnamaldehyde, p-ethylcinnamaldehyde, p-methoxycinnamaldehyde, p-dimethylaminocinnamaldehyde, p-diethylaminocinnamaldehyde, p- nitrocinnamaldehyde, o-nitrocinnamaldehyde, o-allyloxycinnamaldehyde, 4-(3-propenal)cinnamaldehyde, p-sodium sulfocinnamaldehyde, p-trimethylammonium cinnamaldehyde sulfate, p-trimethylammonium cinnamaldehyde-o-methylsulfate, p-thiocyanocinnamaldehyde, p-(S-acetyl)thiocinnamaldehyde, p- (S-N,N-dimethylcarbamoylthio)cinnamaldehyde, p-chlorocinnamaldehyde,

5-phenyl-2,4-pentadienal,

5-(p-methoxyphenyl)-2,4-pentadienal,

2,3-diphenylacrolein,

3.3-diphenylacrolein,

α-methylcinnamaldehyde,

3- methylcinnamaldehyde,

α-chlorocinnamaldehyde,

α-bromocinnamaldehyde,

α-butylcinnamaldehyde,

α-amylcinnamaldehyde,

α-hexylcinnamaldehyde,

2-(p-methylbenzylidine)decanal,

α-bromo-p-cyanocinnamaldehyde,

α-ethyl-p-methylcinnamaldehyde,

p-methyl-a-pentylcinnamaldehyde,

3.4-dimethoxy-α-methylcinnamaldehyde,

a-[(4-methylphenyl)methylene]benzeneacetaldehyde, a-(hydroxymethylene)-4-methylbenzylacetaldehyde, 4-chloro-a-(hydroxymethylene)benzeneacetaldehyde,

a-nonylidenebenzeneacetaldehyde,

and the like, preferably in the trans forms. Trans-cinnamaldehyde is a preferred aldehyde for use in carrying out the invention.

From approx. 0.01 to approx. 4% by weight, preferably from approx. 0.05 to approx. 1% by weight, of one or a mixture of the aldehydes of formula I above, based on the combined weight of (1) aldehyde, (2) surfactant, and (3) the aqueous fluid being treated, will be used with the surfactant to inhibit ferrous metal corrosion.

The surfactants

Anionic, cationic, non-ionic and amphoteric surfactants can be used together with the α,0-unsaturated aldehydes of formula I above in the new corrosion-inhibiting preparations according to the invention.

Anionic surfactants useful in these preparations include: alkyl sulfates, for example sodium alkyl sulfates prepared by sulphation of higher alcohols derived from coconut oil or tallow fatty alcohols, alkylaryl sulphonates, for example polypropylenebenzene- sulfonates,

dialkyl sodium sulfosuccinates, for example dioctyl sodium sulfosuccinate,

and such.

Cationic surfactants that can be used in these preparations include nitrogen atom-containing quaternary compounds of the general formula:

where R represents the same or different long-chain alkyl, cycloalkyl, aryl or heterocyclic groups, and X represents an anion, usually a halide or methosulfate. Among such quaternary compounds are N-alkyl, N-cycloalkyl and N-alkylarylpyridinium halides, for example N-cyclohexylpyridinium bromide,

N-octylpyridinium bromide,

N-nonylpyridinium bromide,

N-decylpyridinyl bromide,

N-dodecylpyridinium bromide,

N,N-dodecyldipyridinium dibromide,

N-tetradecylpyridinium bromide,

N-laurylpyridinium chloride,

N-dodecylbenzylpyridinium chloride,

N-dodecylquinolinium bromide,

quinolinium-(1-naphthylenemethyl) chloride

and such.

Other quaternary ammonium compounds include monochloromethylated and bichloromethylated pyridinium halides, ethoxylated and propoxylated quaternary ammonium compounds, sulfated ethoxylates of alkylphenols and primary and secondary fatty alcohols,

didodecyldimethylammonium chloride,

hexadecylethyldimethylammonium chloride,

2-hydroxy-3-(2-undecylamidoethylamino)-propane-1-triethylammonium hydroxide,

2-hydroxy-3-(2-heptadecylamidoethylamino)-propane-1-triethylammonium hydroxide,

2-hydroxy-3-(2-heptadecylamidoethylamino)-propane-1-triethylammonium hydroxide,

and such.

The cationic surfactants which can be used also include covalently bound nitrogen compounds, for example primary amines, secondary amines or tertiary amines, for example dodecyldimethylamine.

Non-ionic surfactants that can be used in the corrosion-inhibiting preparations according to the invention, ethoxylates of alkylphenols, primary fatty alcohols, secondary fatty alcohols and the like, including alkyl and alkylarylpolyether alcohols, for example the reaction product of trimethyl-1-heptanol with 7 moles of ethylene oxide, the reaction products of octyl or nonylphenol with, for example, from approx. 8 to 30 moles or more of ethylene oxide, polyoxyethylene/polyoxypropylene block copolymers and the like.

Amphoteric surfactants which are useful in carrying out the invention include coco-3-aminopropionate and the like.

From approx. 0.005 to approx. 1% by weight, preferably from approx. 0.01

to approx. 0.5% by weight, of surfactant, based on the combined weight of (1) aldehyde, (2) surfactant and (3)

the aqueous fluid being treated will be used, together with one or more aldehydes of formula I above, to inhibit iron-metal corrosion.

Among the corrosive aqueous fluids to which the new preparations according to the invention can be added to inhibit corrosion on ferrous metals, for example iron and steel, for example oil field equipment, mild steel, refinery equipment, etc., in contact with such fluids are: ( 1) Aqueous solutions of non-oxidising mineral or organic acids, for example hydrochloric acid, hydrofluoric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, citric acid, as well as mixtures thereof. Such acid solutions can also contain chelating agents, for example EDTA, HEDTA, DPTA and the like. The concentration of non-oxidizing mineral or organic acid in such aqueous solutions can vary from approx. 0.1 to approx. 35% by weight, based on the total weight of the solution, and the temperature may vary

from surrounding forest up to approx. 150°C.

(2) Aqueous solutions of alkaline chelating agents, for example the ammonium salts of EDTA, HEDTA and DPTA. The alkaline chelating agent may be present in such solutions in an amount varying from approx. 0.1 to approx. 15% by weight, based on the total weight of the solution. The temperature of these solutions can vary from that of the surroundings and up to approx. 150°C. (3) Aqueous salt solutions or brines, sometimes called "heavy brines", such as solutions of sodium chloride, potassium chloride, calcium chloride, calcium bromide, zinc bromide and mixtures of such salts. Salt concentrations in such solutions can vary from approx. 0.1% by weight to saturation, based on the total weight of the solution. These salt solutions can be mixed with an acidic gas, for example carbon dioxide or hydrogen sulphide, and with hydrocarbons such as mineral oil, crude oil and refined hydrocarbon products. The temperature of these salt solutions can vary from that of the surroundings and up to approx. 200°C.

The corrosion-inhibiting preparations according to the invention will usually be used, in the quantities indicated above, at temperatures which preferably vary from approx. 20 to approx. 200°C. However, the use of amounts of these corrosion-inhibiting preparations which lie outside the above stated ranges is also within the invention and will depend on such factors as the particular corrosive liquid being treated, the water solubility of the inhibitor preparation, the temperature of the corrosive liquid and the time it is in contact with the inhibitor preparation, etc. The exact amount of inhibitor preparation to be used in each particular case can be determined by means of the test methods described in the examples below. These examples, which are provided for illustrative purposes only to assist those skilled in the art to more fully understand the invention, are not to be regarded as expressions of limitation unless they are also set forth in the accompanying claims. All parts and percentages are by weight, unless otherwise stated.

Comparative example 1

01jefelt steel coupons, API, grade J55, with a surface area of 25.8 cm 2 were cleaned and weighed. The steel coupons were cleaned in an ultrasonic cleaner containing a chlorinated hydrocarbon solvent, rinsed with acetone, dried and weighed. Each coupon was hung from a glass peg attached to the cap of a 4-oz (113.4 g) bottle. The coupon was immersed in 100 ml of 15% by weight hydrochloric acid in the bottle and then heated at 66°C in a water bath for 24 hours. At the end of this period, the vessel was cooled, the coupons removed, cleaned with a soft brush, dried with acetone and weighed again.

The uninhibited corrosion or weight loss rate is calculated from the following equation:

a) In g/cm/day

b) Change in the coupon's weight, expressed in grams

c) A conversion unit factor

d) Test time, expressed in hours

e) The coupon's surface area, expressed in cm 2.

The uninhibited corrosion rate was found to be

0.52 g/cm2/day. When the test was run once more with 200 mg of trans-cinnamaldehyde (TCA), the corrosion rate was reduced to 0.037 g/cm 2 /day. Percent protection provided by TCA alone was calculated from the following equation:

Thus, TCA gave 93% protection for J55 steel. When tested under identical conditions, phenylacetaldehyde, 2-phenylpropionaldehyde and 3-phenylpropionaldehyde gave 0% protection to J55 steel.

However, percent protection provided by TCA alone was not reproducible. The results of four identical runs, as described above, with TCA alone, using J55 steel coupons, at 66°C, 15% HCl, 24 hour tests are shown below.

Comparative example 2

Using the general method from Comparative Example 1, surfactants were tested in 15% hydrochloric acid at 66°C. Three known surfactant corrosion inhibitors were tested. The three inhibitors were cyclododecylamine (200 mg/100 ml), dodecylpyridinium bromide (50 mg/100 ml) and dodecylquinolinium bromide (50 mg/100 ml).

The percentage of protection provided by each of the mentioned inhibitors for each type of steel is given in the following table:

In an identical test with DDPB at 50 mg/100 ml, conducted at a different point, DDPB gave 0% protection for J55 steel.

Example I

The procedure from Comparative Example 1 was repeated eight times in every respect with the exception of the variations shown in Table II below. Trials 1 and 5 are comparison trials, carried out without surfactant. Experiments 2-4 and 6-8 demonstrate the protection afforded to steel samples in a corrosive acidic liquid by TCA in combination with surfactants.

Example II

The procedure of Comparative Example I was repeated in all respects, with the exception of the variations shown in Table III below, to demonstrate the protection afforded to J55 steel specimens in corrosive acidic liquids by aldehydes falling within the range of Formula I above in combination with surfactants.

Example III

Control values for THEO and DDPB

Conditions: 66 C, 24 hour tests, J55 steel

Example IV

Effect of surfactant concentration and TCA in 28% HC1

J55, 66°C, 24 hour tests

Example V

Effect of acid concentration and steel 4.0 hours, 29°C, [TCA] = 0.32 g / 100 ml [DDPB] = 0.08 g / 100 ml

Example VI Effect of steel 20% HC1, 3.2 hours, 93°C [TCA] - 0.16 g ( 100 ml [DDPB]= 0.04 g / 100 ml

The above discussion and associated illustrations of the present invention are primarily directed to preferred embodiments and practice thereof. However, it will be clear to those skilled in the art that numerous changes and modifications in the actual meaning of the ideas described here can easily be made without deviating from the spirit and framework of the invention as defined in the accompanying claims.

Claims (10)

1. Preparation for inhibiting the attack of aqueous corrosive fluids on ferrous metal, characterized by (A) a ct,/ 3-unsaturated aldehyde with the following general formula where: is a saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to about 12 carbon atoms, a substituted saturated or unsaturated aliphatic hydrocarbon group containing from about 3 to approx. 12 carbon atoms and which also contains one or more non-interfering substituents, an aryl group, a substituted aryl group containing one or more non-interfering substituents, or a non-interfering substituent as such, R2 is hydrogen, a saturated or unsaturated aliphatic hydrocarbon group containing from approx. 1 to approx. 5 carbon atoms, a substituted saturated or unsaturated aliphatic hydrocarbon group containing from 1 to about 5 carbon atoms and which also contains one or more non-interfering substituents, an aryl group, a substituted aryl group containing one or more non-interfering substituents, or a non-interfering substituent as such, and R^ is hydrogen, a saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to car 12 carbon atoms, a substituted saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to approx. 12 carbon atoms and which also contains one or more non-interfering substituents, an aryl group, a substituted aryl group containing one or more non-interfering substituents, or a non-interfering substituent as such, wherein the total number of carbon atoms in substituents represented by R-^ , R 2 and R^ varies from 1 to about* 16, and (B) a surfactant. 2. Preparation as stated in claim 1, characterized in that the aldehyde is present in an amount of from approx. 0.01 to approx. 4% by weight and that said surfactant is present in an amount of from approx. 0.005 to about 1% by weight, the percentages being based on the total weight of said aldehyde, said surfactant and said aqueous corrosive fluid. 3. Preparation as stated in claim 1 or 2, characterized in that the aldehyde is t-cinnamaldehyde. 4. Preparation as stated in claim 1 or 2, characterized in that the aldehyde is t-cinnamaldehyde and that said surfactant is an anionic surfactant. 5. Preparation as stated in claim 4, characterized in that the anionic surfactant is an alkyl-aryl sulphonate. 6. Preparation as stated in claim 1 or 2, characterized in that the aldehyde is t-cinnamaldehyde and that said surfactant is a cationic surfactant. 7. Preparation as stated in claim 6, characterized in that the surfactant is dodecylpyridinium bromide. 8. Preparation as stated in claim 1 or 2, characterized in that the aldehyde is t-cinnamaldehyde and that said surfactant is a non-ionic surfactant. 9. Preparation as stated in claim 8, characterized in that the surfactant is the reaction product of trimethyl-1-heptanol with 7 mol of ethylene oxide. 10. Process for inhibiting the attack of aqueous corrosive fluids on ferrous metal, characterized by contacting the ferrous metal with a preparation comprising: (A) an α,3-unsaturated aldehyde having the general formula: where: R^ is a saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to approx. 12 carbon atoms, a substituted saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to approx. 12 carbon atoms and which also contains one or more non-interfering substituents, an aryl group, a substituted aryl group containing one or more non-interfering substituents, or a non-interfering substituent as such, R2 is hydrogen, a saturated or unsaturated aliphatic hydrocarbon group containing from approx. 1 to approx. 5 carbon atoms, a substituted saturated or unsaturated aliphatic hydrocarbon group containing from 1 to about 5 carbon atoms and which also contains one or more non-interfering substituents, an aryl group, a substituted aryl group containing one or more non-interfering substituents, or a non-interfering substituent as such, and R^ is hydrogen, a saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to approx. 12 carbon atoms, a substituted saturated or unsaturated aliphatic hydrocarbon group containing from approx. 3 to approx. 12 carbon atoms, and which also contains one or more non-interfering substituents, an aryl group, a substituted aryl group containing one or more non-interfering substituents, or a non-interfering substituent as such, with the total number of carbon atoms in substituents represented by R 1 , R 2 and R varying from 1 to approx. 16, and (B) a surfactant, particularly as defined in claims 4 to 9.