Corrosion inhibitor compositions

Details Corrosion inhibitor compositions Corrosion inhibitor compositions

1999-03-15

2002-09-10

McKane, Joseph K. (Department: 1626)

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C548S349100, C548S352100

Reexamination Certificate

active

06448411

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to a process for producing and a method for using a corrosion inhibitor composition for reducing the corrosion rate of a metal by a fluid having at least one corrosion agent. More specifically, the invention relates to synthesis and use of one or more quaternized compounds having an imino or amido moiety, for example quaternized imidazoline(s) having an imino or amido moiety, in such a corrosion inhibitor composition used in oil and gas-field applications.
BACKGROUND OF THE INVENTION
In order to reduce the rate of corrosion of metals, and particularly metals containing iron, from one or more metal corrosion agents present in a fluid (i.e., a gas, liquid, slurry or a mixture thereof a corrosion inhibitor is frequently introduced into the fluid to reduce the rate of corrosion of the metal vessel, pipeline and/or equipment used to store and transport the fluid. In oil and gas-field applications, for example, corrosion inhibitors are added to a wide array of systems, including without limitation, cooling systems, refinery units, pipelines, steam generators and oil or gas producing units in efforts to combat a variety of types of corrosion.
One example of corrosion, among others, typically encountered in the transport of a fluid containing one or more corrosion agents (hereinafter simply referred to as “fluid”) is flow-induced corrosion. In the case of flow-induced corrosion, the degree of corrosion that occurs is presently believed to depend on a variety of factors, including the corrosiveness of the fluid itself, the metallurgy of the pipeline and the shear rate, temperature, and pressure of the fluid.
Also, to the extent that a corrosion inhibitor is used, the inhibitor's ability to reduce the rate of corrosion of a metal from flow-induced corrosion, among other types of corrosion, is presently believed to depend on at least two factors. One factor is the inhibitor's chemical affinity for the metal surface. A second factor is the inhibitor's resistance to breakdown under high shear conditions. Therefore, it is currently believed that the rate of corrosion, especially flow-induced corrosion, of a metal more likely will be reduced where the inhibitor has good chemical affinity for the metal surface and can resist breakdown under high shear conditions. Many inhibitors have been developed to reduce corrosion. However, their activity is sufficiently low that higher concentrations are oftentimes required to effectively treat a pipeline, most particularly where flow-induced corrosion is a problem, thereby increasing operating costs.
Conventionally, the presence of a free amine moiety in inhibitors, such as that described in U.S. Pat. No. 5,322,640, has been thought to be desirable because a pendant alkyl amine group would have at least one free amine (e.g., a NH
2
group) available for interaction with a metal surface. Accordingly, until the disclosure of the present invention, those skilled in the art of synthesizing corrosion inhibitors refrained from further reacting the intermediate product produced in U.S. Pat. No. 5,322,640 and/or producing imidazoline derivatives where the group pendant to the imidazoline ring contains either an imino moiety, generally described as —N═CH—R or, an amido moiety, generally described as —N—(C═O)—R.
Conventionally, such imino and amido imidazolines and their derivatives generally were considered to have little to no corrosion inhibition activity or potentially to have detrimental effects on the reaction product's corrosion inhibition activity. Specifically, it was understood by those skilled in the art that the lack of a pendant group with a heteroatom (e.g., nitrogen, sulfur or oxygen) having a pair of nonbonding electrons freely available for interaction with a metal surface would have an adverse affect on the performance of the inhibitor. In such instances, the pendant group would lose its freely available pair of nonbonding electrons on the heteroatom of the pendant group because of electron delocalization. In turn, it was thought such electron delocalization would reduce the compound's ability to interact with a metal surface, and thereby reduce its overall inhibition activity.
A corrosion inhibitor is desired that has improved inhibition performance as compared with inhibitors presently used for treating systems experiencing flow-induced corrosion, among other corrosion problems.
A substantial number of corrosion inhibitors have been disclosed for reducing the rate of corrosion of metal-containing storage and transport systems. More specifically, a number of corrosion inhibitors have been disclosed, most particularly for treating flow-induced corrosion, including, among others, quaternized imidazolines. A need exists, however, for a corrosion inhibitor with improved reduction in the rate of corrosion, for example flow-induced corrosion, of metals.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a process for producing a composition comprising at least a quaternized compound, comprising the steps of: (a) selecting a first organic compound from the group consisting of: (i) substituted and unsubstituted, saturated and unsaturated fatty acids having from about
6
to about
30
carbon atoms; (ii) substituted and unsubstituted, saturated and unsaturated fatty acids having from about 6 to about 30 carbon atoms, wherein said fatty acid is at least oxygenized, sulfurized or phosphorylized; and (iii) combinations thereof; (b) selecting an alkyl polyamine from the group having the general formula:
H
2
N—CH
2
—(CH
2
)p—NH—(CH
2
)
q
—NH
2
wherein p=1 to about 5 and q=2 to about 10; (c) selecting a second organic compound from the group consisting of (i) carbonyl compounds having from 2 to about 31 carbon atoms; (ii) fatty acids having from 2 to about 30 carbon atoms; and (iii) combinations thereof; (d) selecting a third organic compound from the group consisting of (i) substituted and unsubstituted, &agr;,&bgr;-unsaturated carboxylic fatty acids, and amide and ester derivatives thereof, having from about 3 to about 11 carbon atoms; (ii) substituted and unsubstituted, &agr;,&bgr;-unsaturated sulfonic and phosphonic fatty acids having from about 2 to about 11 carbon atoms; and (iii) combinations thereof; (e) mixing said first organic compound and said alkyl polyamine in a mole ratio in a range of from about 0.6:1 to about 1.2:1 to produce at least one intermediate compound, wherein said mole ratio is the total moles of said first organic compound to the total moles of said alkyl polyamine; (f) mixing said at least one first intermediate compound with said second organic compound to produce a second intermediate compound; and (g) mixing said second intermediate compound with said third organic compound to produce said composition.
According to another aspect of the present invention, there is provided a composition produced by the process described above.
According to a further aspect of the present invention, there is provided a method of using the composition produced by the process described above for reducing the corrosion rate of a metal by a fluid having at least one corrosion agent, said method comprising: (a) introducing said composition into said fluid; and (b) contacting said metal with the fluid of step (a).
According to yet another aspect of the present invention, there is provided a method of using a corrosion inhibitor composition for reducing the corrosion rate of a metal by a fluid having at least one corrosion agent, said method comprising: (a) introducing said corrosion inhibitor composition into said fluid, said inhibitor composition having at least one compound wherein said compound is a quaternized compound having the general formula:
wherein, R
1
is a moiety selected from the group consisting of: (i) substituted and unsubstituted, saturated and unsaturated alkyl groups having from about 5 to about 29 carbon atoms; (ii) substituted and unsubstituted, saturated and unsaturated alkyl groups having fro

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