US3056832A - Partial amides - Google Patents

Description

United States Patent Ofiice 3,056,832 Patented Oct. 2, 1962 This invention relates to amide-acids of polyamines, (hereafter referred to as partial amides). More particularly, this invention relates to partial amides formed by reacting an aliphatic polyamine having only one primary amino group with a polycarboxylic acid under such conditions that the polyamine is not converted to the cyclic amidine structure and only one carboxylic acid group of the polycarboxylic acid is reacted with the primary amine to form an amide.

This invention also relates to a process of using these partial amides as corrosion inhibitors in preventing the corrosion of metals, most particularly iron, steel and ferrous alloys. The corrosion inhibitors disclosed herein are particularly useful in preventing the corrosion of oil equipment, for example, in producing wells, pipe lines, refineries, tank storage, etc., which are in contact with corrosive oil-containing medium, for example, in oil wells producing corrosive oil or oil-brine mixtures in refineries, and the like. These compositions possess properties which impart to metals resistance to attack by a wide variety of corrosive agents, among which may be mentioned brines, organic and inorganic acids, CO H 0, etc., and combinations thereof.

Heretofore, a wide variety of polyamines have been employed to inhibit the corrosion of oil well equipment. Although I had expected polyamines having only one primary amino group would be very effective in inhibiting oil field corrosion, for example, the Duomeens sold by Armour Co. I found that these compounds had very poor corrosion inhibiting properties.

However, I have now unexpectedly discovered that derivatives of these polyamines, particularly the partial amides thereof, are much more effective as corrosion inhibitors than the corresponding polyamines from which they are derived.

More specifically, the above described compounds may be described by the formula:

R R H o 0 RlLlA-(lT-A) ,.I I-i Jz (i l-0H)...

wherein R is an aliphatic radical having for example from l-30 or more carbons, but preferably from 8 to 18 carbons; R is either hydrogen or an aliphatic group having for example, from '1 to 18 carbons, but preferably 0 to 2 carbons; A is an alkylene radical having, for example, 2 to 6 carbons, but preferably 2 to 3 carbons; n is a number varying, for example, from 0 to 4, but preferably from 0 to 2, Z is the residue of the polycarboxylic acid which comprises, for example, a saturated or unsaturated aliphatic radical, a cycloaliphatic radical, an

aryl radical, an aralkyl radical, an alkaryl radical, an aryl- 6Q oxy aryl radical, and the like, and m is the number of unamidified carboxylic acid groups of the polycarboxylic acid, for example, from 1-4, but preferably 1.

More specifically, the corrosion inhibiting aspect of this invention relates to a method for inhibiting corrosion of ferrous metals by hydrocarbon fluids containing water and corrosive materials, such as H S, CO inorganic acids, organic acids, etc., combinations of these materials with each other, combinations of each of said corrosive materials with oxygen, and combinations of said materials with each other and oxygen, which comprises adding to said fluids at least 5 parts per million of the above partial amides, said compounds being sufficiently soluble in the hydrocarbon fluid to inhibit corrosion.

THE POLYAMINE The polyamines employed in the present invention are alkylene polyamines having at least 2 nitrogen atoms and characterized by the fact that they have only one primary amino group which is susceptible of amidification under the condition of reaction. These correspond to the formula haxing the same meaning as stated above in the formula for the partial amide.

The preparation of polyalkylene amines is well known. For example, they are readily prepared from olefin dichlorides, particularly those having from 2-10 carbon atoms, by reacting these dichlorides with ammonia and amines. Such polyamines are alkylated in the manner commonly employed for alkylating monoamines. For instance, alkylated products are derived by reaction between alkyl chlorides, such as propyl chloride, butyl chloride, amyl chloride, cetyl chloride, dodecyl chloride, octadecyl chloride, etc. Alkylation is not limited solely to the introduction of the alkyl group, but as a matter of fact, a radical can be introduced characterized by the fact that the carbon atom chain is interrupted at least once by an oxygen atom. In other words, alkylation is accomplished by compounds which are essentially alkoxyalkyl chlorides as, for example, the following:

Examples of suitable polyamines comprise the following polyamines which have one terminal primary amino group capable of amidification under the conditions of reaction and which have been alkylated on one or more of the remaining nitrogen atoms. These amines after formation to the partial amide should be hydrocarbon soluble.

These alkylated, primary amine-containing polyamines can be derived by alkylation of a member of the following representative series:

ethylene diamine propylene diamine butylene diamine, etc.

diethylene triamine dipropylene triamine dibutylene triamine, etc.

triethylene tetramine tripropylene tetramine tributylene tetramine, etc.

tetraethylene pentamine tetrapropylene pentamine tetrabutylene pentamine, etc.

mixtures of the above mixed ethylene, propylene, and/or butylene, etc., polyamines and other members of the series.

They may comprise the hexamethylene radicals, or higher, and hexamines, heptamines, etc.

For example, where n=0, one would obtain polyamines of the formula wherein R is preferably a fatty alkyl group having more than 8 carbons, for example,

The alkyl group on these amines can be derived from any suitable source, for example, from compounds of animal and vegetable origin, such as cocoanut oil, tallow, etc. Higher amines of this type are described in US. Patent 2,267,205, for example, of compounds of the type where R is, for example, a fatty alkyl of, for example, 8-18 carbons or higher.

Another method of preparing these amines comprises adding the desired amine across the double band of acrylonitrile and then reducing this additional compound to the diamine. The Duomeens of Armour Co. are prepared in this manner.

Examples of suitable amines are found in the Duomeens which are compounds of the formula where R is derived from fatty acids: Duomeen 12 which is derived from lauric acid (dodecyl 95%, decyl 2%, tetradecyl 3%); Duomeen C from coconut (octyl 8%, decyl 9%, dodecyl 47%, tetradecyl 18%, hexadecyl 8%, octadecyl octadecenyl 5%); Duomeen S from soya (hexadecyl 20%, octadecyl 17%, octadecenyl 26%, octadecadienyl 37%); Duomeen T from tallow (tetradecyl 2%, hexadecyl 24%, octadecyl 28%, octadecenyl 46%); and other Duomeens described more fully in the technical booklets published by Armour Chemical Company.

THE POLYCARB OXYLIC ACIDS The polycarboxylic acids employed can be varied widely. In general, they can be expressed as follows:

where R comprises a saturated or unsaturated aliphatic, cycloaliphatic, aromatic, etc., radical, and n is a whole number equal to 2 or more, for example, 2-4, but preferably 2. These polycarboxylic acids must be carefully reacted with the polyamines so that no cyclization occurs resulting in the formation of cyclic amidines. These should also be reacted in less than stoichiometric amounts so that the amide-acid is formed. Thus, only one mole of Water should be removed per mole of amine.

A convenient method of preparing these partial amides comprises reacting the polyamine with the anhydrides of these acids. Since the anhydride reacts readily at low temperatures for example 0100 C., but preferably 0-50 C. without the elimination of water, it is employed as the preferred method of preparing these compounds. For example, one employs succinic anhydride in the following reaction UH -CH9 room 12 as- 2)a a 0=C =0 H temperature By running the reaction at these low temperatures, no amidine cyclization occurs.

Examples of the polycarboxylic acids or anhydrides thereof comprise those of the aliphatic series, for example, oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, nonanedicarboxylic acid, deciiaiiedicarboxylic acids, undecanedicarboxylic acids, and the Examples of unsaturated aliphatic polycarboxylic acids comprise fumaric, maleic, mesocenic, citraconic, glutonic, itaconic, muconic, aconitic acids, and the like.

Examples of aromatic polycarboxylic acids comprise phthalic, isophthalic acids, terephthalic acids, substituted derivatives thereof (e.g. alkyl, chloro, alkoxy, etc. derivatives), biphenyldicarboxylic acid, diphenylether, dicar- 4 boxylic acids, diphenylsulfonedicarboxylic acids and the like.

Higher aromatic polycarboxylic acids containing more than two carboxylic groups comprise bemimellitic, trimellitic, trimesic, mellophanic, prehnitic, pyromellitic acids, mellitic acid, and the like.

Other polycarboxylic acids comprise the dimeric, trimeric and other poly acids, for example, those sold by Emery Industries, such as dilinoleic acid and the like. Other polycarboxylic acids comprise those containing ether groups, for example, diglycollic acid. Mixtures of the above acids can be advantageously employed.

However, as stated above the use of the acids themselves requires a great deal of control in order to avoid the formation of the cyclic amidine structure during heating. Therefore, these partial amides are preferably pre pared by reacting the polyamines with the polycarboxylic anhydrides. An excellent discussion on anhydrides is found in Fatty Acids and their Derivatives by A. W. Ralston (John Wiley, N.Y. 1948) pp. 238-240 and 799800, and in Synthetic Organic Chemistry by Wagner and Zook (Wiley 1953) pp. 558-564.

A class of very useful anhydrides comprises those derived from the addition of cyclic olefin anhydrides to dienes according to the Diels-Alder reaction where R is hydrogen or a substituted group such as hydrocarbon, chlorine, etc.

Maleic anhydrides and several related derivatives have been added to a large number of dienes. For example, the reaction of butadiene and maleic anhydride occurs at 50 in benzene solution to give 1,2,3,6-tetrahydrophthalic anhydride in a yield of 97%. This method furnished very important partially hydrogenated aromatic anhydrides. References to these anhydrides can be found in Organic Reactions, vol. 4, Wiley (1948), pp. 1, 41; J .A.C.S., Fieser & Mavella, 64, 806 (1942); J.A.C.S. Cope & Henich, 72, 984 (1950), etc.

In general, the partial amides are prepared by slowly adding the carboxylic anhydride to the polyamine, keeping the temperature below 50 C. The polyamine can either be used as such or dissolved in a suitable solvent such as benzene, xylene, etc.

The following examples are presented as illustrative of the preparation of the partial amides.

Example 1 One mole of succinic anhydride is slowly added over /2 hour to a well-stirred reaction vessel containing one mole of Duomeen-T, (Armour Co.)

the fatty alkyl group R being derived from tallow. The temperature of the reaction is kept below 50 C. The product of the reaction is Example 2 The process of Example 1 is repeated except that Duomeen-S (Armour Co.)

the fatty alkyl group being derived from Soya, and adipic anhydride are employed. The product is H II II R'g(CHz)3-NC(CH2)4COH Example 3 The prior example is repeated except that and phthalic anhydride are employed. The product is Example 4 The process of the prior example is repeated with Amine ODT (Monsanto Co.)

and sebacic anhydride to yield Example 5 The above example is repeated employing Duomeen 12. (Armour Co.)

TABLE I Partial Amides EX. R R R" A 11. B

Tall0w H (011m 0 (OH2)2 80373.... H (CH2) O (CH2)4- I 3 6101333.." H H. (CH2)2 2 4 O12H25---- H H 2): 1 (CH2)2- 5 C12H25 H .l (GEM 0 -CH=CH 6 C4H7 H CH2 3 0 -(CH2)3 6O 7 Q 111 C411 (OH2)2 O s 0181133-.-. H (011m 0 (on,'

9 Ci2 s5.. H (cum 0 10 C1sHas H H (CHM 1 (I 11 Cis ss H 2M 0. 2)2 12 0000111... H (CH2)3 0 -(CH2)zti Of course, it will be realized that other polyamines and anhydrides can also be employed. In addition, by careful control of the reaction, the free acid itself can be substituted for the anhydride.

USE AS CORROSION INHIBITOR More specifically, this phase of the invention relates to the inhibition of corrosion in the petroleum industry with specific reference to producing wells, pipe lines, refineries, tank storage, etc.

The use of a corrosion inhibiting agent in the oil industry and other industries, and particularly for the protection of ferrous metals, is well known. For example, see US. Patents Nos. 2,736,658 dated February 28, 1954, to Pfohl et al., and 2,756,211 dated July 24, 1956, to Jones, and 2,727,003 dated December 13, 1955 to Hughes.

More specifically then, and particularly from the standpoint of oil production, this aspect of the invention relates to inhibiting corrosion caused by hydrogen sulfide, carbon dioxide, inorganic, organic acids, combinations of each with oxygen, and with each other and oxygen. More particularly, it relates to treating wells to mitigate metal corrosion and associated difiiculties.

It should also be pointed out that the corrosiveness of oil Well brines will vary from well to well, and the proportion of corrosion inhibiting agent added to the well fluids should also be varied from well to well. Thus, in some wells it may be possible to effectively control corrosion by the addition of as little as 5 ppm. of my new compositions to the well fluids, whereas in other wells, it is necessary to add 200 ppm. or more.

In using my improved compositions for protecting oil Well tubing, casing and other equipment which comes in contact with the corrosive oil-brine production, I find that excellent results may be obtained by injecting an appropriate quantity of a selected composition into a producing Well so that it may mingle with the oil-brine mixture and come into contact with the casing, tubing, pumps and other producing equipment. I may, for example, introduce the inhibiting composition into the top of the casing, thus causing it to flow down into the well and thence back through the tubing, etc. In general, I have found that this procedure suffices to inhibit corrosion throughout the entire system of production, and collection, even including field tank-age.

In case serious emulsion or gel problems are encountered, demulsifiers are advantageously added. This is important not only to avoid the troublesome emulsions and gels themselves, but also to improve corrosion inhibition. The explanation of less effective corrosion inhibition in the presence of emulsions apparently is that the inhibitor is somewhat surfaceactive. That is, it is concentrated at interfacial surfaces. Since this surface is great in an emulsion, most of the inhibitor will be concentrated in these interfaces and little will remain in the body of the oil for deposition on the metal surfaces. In many wells, oil-in-water type emulsions often occur naturally. In such wells the inhibitors herein described tending to form water-in-oil type emulsions, often decrease the emulsion problems naturally present. Thus, in addition to being effective corrosion inhibitors, the herein described products tend to eliminate emulsion problems which sometimes appear when some of the present day inhibitors are used in oil Wells or refinery processing.

The method of carrying out our process is relatively simple in principle. The corrosion preventive reagent is dissolved in the liquid corrosive medium in small amounts and is thus kept in contact with the metal surface to be protected. Alternatively, the corrosion inhibitor may be applied first to the metal surface, either as is, or as a solution in some carrier liquid or paste. Continuous application, as in the corrosive solution, is the preferred method, however.

The present process finds particular utility in the protection of metal equipment of oil and gas wells, especially those containing or producing an acidic constituent such as H 8, CO inorganic, organic acids, and the like. For the protection of such wells, the reagent, either undiluted or dissolved in a suitable solvent, is fed down the annulus of the well between the casing and producing tubing where it becomes commingled with the fluid in the well and is pumped or flowed from the well with these fluids, thus contacting the inner wall of the casing, the outer and inner wall of tubing, and the inner surface of all well-head fittings, connections and flow lines handling the corrosive fluid.

Where the inhibitor composition is a liquid, it is conventionally fed into the Well annulus by means of a motor driven chemical injector pump, or it may be dumped periodically (e.g. once every day or two) into the annulus by means of a so-called boll weevil device or similar arrangement. Where the inhibitor is a solid, it is dropped into the well as a solid lump or stick, it may be blown in as a powder with gas, or it may be washed in with a small stream of the Well fluids or other liquid. Where there is gas pressure on the casing, it is necessary, of course, to employ any of these treating methods through a pressure equalizing chamber equipped to allow introduction of reagent into the chamber, equalization of pressure between chamber and casing, and travel of reagent from chamber to well casing.

Occasionally, oil and gas wells are completed in such a manner that there is no opening between the annulus and the bottom of the tubing or pump. This results, for example, when the tubing is surrounded at some point by a packing held by the casing or earth formation below the casing. In such wells the reagent may be introduced into the tubing through a pressure equalizing vessel, after stopping the flow of fluids. After being so treated, the well should be left closed in for a period of time suflicient to permit the reagent to drop to the bottom of the well.

For injection into the well annulus, the corrosion inhibitor is usually employed as a solution in a suitable solvent, such as mineral oil, methylethyl ketone, xylene, kerosine, or even water. The selection of solvent will depend much upon the exact reagent being used and its solubility characteristics. It is also generally desirable to employ a solvent which will yield a solution of low freezing point, so as to obviate the necessity of heating the solution and injection equipment during winter use.

For treating wells with packed-off tubing, the use of solid sticks or plugs of inhibitor is especially convenient. These are prepared by blending the inhibitor with a mineral Wax, asphalt or resin in a proportion suflicient to give a moderately hard and high-melting solid which can be handled and fed into the Well conveniently.

The amount of corrosion preventive agent required in our process varies with the corrosiveness of the system, but where a continuous or semi-continuous treating procedure is carried out as described above, the addition of reagent in the proportion of from 5 parts per million to 1000 parts per million or more parts of corrosive fluid will generally provide protection.

These corrosion inhibitors can be used in combination with other well-known corrosion inhibitors, for example, the cyclic amidine structures, the amido cyclic amidine structures, and the amino cyclic amidine structures, as disclosed in the Blair and Gross Reissue Patent No. 23,227. When the herein described products are mixed with corrosion inhibitors of the conventional type in the ratio of one-to-three, one-to-one, three-to-one, or the like, in numerous instances the effectiveness of the corrosion inhibitor thus obtained is often significantly greater than the use of either one alone.

Since these products are basic they can be combined with various acids to produce salts in which oil solubility is increased or decreased. Likewise, water solubility may be increased or decreased. For instance, the products may be mixed with one or more moles of an acid, such as higher fatty acids, dimerized fatty acids, naphthenic acids,

8 acids obtained by the oxidation of hydrocarbons, as well as sulfonic acids such as dodecylbenzene sulfonic acid, petroleum mahogany acids, petroleum green acids, etc.

What has been said in regard to the acids which increase oil solubility and decrease water solubility applies with equal force and effect to acids of the type, such as acetic acid, hydroxyacetic acid, gluconic acid, etc., all of which obviously introduce hydrophile character when they form salts or complexes, if complexes are formed.

As pointed out previously, the addition of corrosion inhibitors, particularly in the form of a solution by means of a metering pump or the like, is common practice. The particular corrosion inhibitors herein described are applied in the same manner as other corrosion inhibitors intended for use for the same purpose. For sake of brevity, as to the use of the corrosion inhibitor and its solution in a suitable solvent such as mineral oil, methyl ethyl ketone, xylene, kerosene, high boiling aromatic solvent, or even Water.

The following examples are presented to illustrate the superiority of the instant compounds as corrosion inhibitors.

Static weight loss tests. These tests are run on both synthetic and naturally occurring fluids. The test procedure involves the measurement of the corrosive action of the fluids inhibited by the compositions herein described upon sandblasted S.A.E. 1020 steel coupons measuring x 3% inches under conditions approximating those found in an actual producing Well, and the comparison thereof with results obtained by subjecting identical test coupons to the corrosive action of identical fluids containing no inhibitor.

Clean pint bottles were charged with 200 ml., of 10% sodium chloride solution saturated with hydrogen sulfate and 200 ml. of mineral spirits and a predetermined amount of inhibitor was then added. In all cases the inhibitor concentration was based on the total volume of fluid. Weighed coupons were then added, the bottles tightly sealed and allowed to remain at room temperature for 3 days. The coupons were then removed, cleaned by immersion in inhibited 10% hydrochloric acid, dried and Weighed.

The changes in the weight of the coupons during the corrosion test were taken as a measurement of the effectiveness of the inhibitor compositions. Protection percentage was calculated for each test coupon taken from the inhibited fluids in accordance with the following formula:

X =Percent Protection in which L is the loss in weight of the coupons taken from uninhibited fluids and L is the loss in weight of coupons which were subjected to the inhibited fluids.

TABLE 2 Static Weight Loss Test 0 O H H II II RNA--N-C-B-C OH Commercial Percent Ex. R A B Source of Protec- Amine tion C1sH;5 (CH1); (CH1), Duomeen O-.- 98. 9 Tallow (OHm (CH Duomeen T-.- 95. 3 Coconut.. (0H2)a (CH1): Duomeen C--- 97. 6

H CwHas-N-(CHflaNH: Duomeen O..- 65. 5

H R'N(CH2)3NH1 Duomeen O... 71. 0

Free amine.

Stirring tests F.).These tests are run on synthetic fluids. The procedure involves the comparison of the amount of iron in solution after a predetermined interval of time of contact of a standardized iron surface with a two-phase corrosive medium with similar determinations in systems containing inhibitors.

Six hundred ml. beakers equipped with stirrers and heaters are charged with 400 ml. of sodium chloride containing 500 p.p.m. acetic acid and 100 ml. of mineral spirits. The liquids are brought to temperature and a 1 x 1 inch sand blasted coupon is suspended by means of a glass hook approximately midway into the liquid phase of the beaker. The stirrer is adjusted to agitate the liquids at such a rate as to provide good mixing of the two layers.

After 30 minutes samples of the aqueous phase are taken and the iron content of each sample is determined by measuring the color formed by the addition of hydrochloric acid and potassium thiocyanate in a photoelectric colorimeter.

The protection afforded by an inhibitor is measured by comparison of the amount of light absorbed by inhibited and uninhibited samples run simultaneously. Percent protection can be determined by the following formula:

where A is the present light absorbed by an uninhibited sample and A is the same value for an inhibited sample.

X 100 Percent Protection These products are effective not only as corrosion inhibitors but can be used for a number of other purposes. For instance, they are useful as asphalt additives to increase the adhesiveness of the asphalt to the mineral aggregates. In the form of Water soluble salts, they are useful as bactericides in the secondary recovery of oil. They may be subjected to extensive oxyalkylation by means of ethylene oxide, propylene oxide, butylene oxide, or the like. These are oxyalkylated and still have oil solubility as, for example, by the addition of propylene oxide or butylene oxide, or are oxyalkylated to produce water solubility as, for example, by means of ethylene oxide or glycide. They are also oxyalkylated by combinations of propylene oxide and ethylene oxide so that both water solubility and oil solubility remain. Such products are useful for a variety of purposes and particularly for those where nonionic surfactants or sequestered cationic surfactants are indicated.

Having described my invention what I claim as new and desire to secure by Letters Pattent is:

1. A partial amide of the formula 0 H H I ll H RNA(NA)nNC-Z( OH)m wherein R is an alkyl group, having at least 12 carbon atoms, A is an alkylene radical, n is 04, m=14, and Z is a member selected fro-m the group consisting of alkylene, alkenylene, phenylene and diphenylene radicals.

2. A partial amide of the formula 0 0 H H II [I RNA-N-C Z-C OH wherein R is an alkyl group having 12-18 carbon atoms, A is an alkylene radical having 2-3 carbons and Z is a member selected from the group consisting of alkylene, alkenylene, phenylene and diphenylene radicals.

Where R is the hydrocarbon group derived from tallow, the hydrocarbon chain length composition being tetradecyl 2%, hexadecyl 24%, octadecyl 28%, and octadecenyl 46%.

where R is the hydrocarbon group derived from coconut oil, the hydrocarbon chain length composition being octyl 8%, decyl 9%, dodecyl 47%, tetradecyl 18%, hexadecyl 8%, octadecyl 5% and octadecenyl 5%.

Claims (1)

1. A PARTIAL AMIDE OF THE FORMULA