United States Patent Office

3,134,759 United States Patent Office Patented May 26, 1964 2 hydroxy polyalkylene polyamines wherein one or more 3,134,759 of the alkylene groups in a polyalkylene polyamine con TAL, O, AMDE FOR NHE TENG CORROSION tains a hydroxyl group. Still another class of polyamines Wiliard H. Kirkpatrick, Sugar Laad, and Virgi L. Seae, which may be employed for the practice of the invention Houston, Tex., assignors to Naco Chemical Company, are the hydroxy alkyl polyalkylene polyamines wherein a corporation of Delaware one or more of the nitrogen atoms in the polyalkylene No Drawing. Filed Jan. 1, 1960, Ser. No. 1,44 polyamine has attached thereto a hydroxy alkyl radical, 5 Claims. (C. 260-97.5) for example, hydroxy ethyl diethylenetriamine, hydroxy This invention relates to new and useful chemical com ethyl dipropylenetriamine and homologues thereof. pounds and to the method of preparation thereof. IO . The terminal amino groups of the polyamine are pri This application is a continuation-in-part of copending mary amino groups and the intermediate amino groups application Serial No. 365,771, filed July 2, 1953 now (or imino groups) are secondary. In an amidification abandoned. reaction the acylation of the polyamine can take place One of the objects of the invention is to provide new either at the primary or secondary groups, but acylation chemical compounds which are especially useful for in 5 preferentially occurs at the primary groups until these hibiting corrosion of metal equipment in oil and gas Wells. groups are acylated. When the primary amino groups Another object is to provide chemical compounds are blocked by acyl groups, acylation or amidification which are useful in inhibiting corrosion of pipe or equip occurs at the secondary amino groups. ment that is in contact with a corrosive oil-containing The organic monocarboxy acids which are reacted with medium in oil wells, refineries, or the like. 20 the aforesaid polyamines in order to produce corrosion Still a further object of the invention is to provide inhibiting compositions for the practice of the invention chemical compounds for inhibiting corrosion of metals in include, for example, caprylic acid, prelargonic acid, cap systems which are subject to contact by various corrosive .ric acid, undecylic acid, lauric acid, tridecoic acid, myris agents, such as carbon dioxide, aqueous or non-aqueous tic acid, pentadecanoic acid, palmitic acid, margaric acid, solutions of carbon dioxide, hydrogen sulfide, aqueous or 25 Stearic acid, nondecylic acid, arachidic aid, behenic acid, non-aqueous solutions of hydrogen sulfide, brines, weak carnaubic acid, hyenic acid, carboceric acid, cerotic acid, inorganic acids and organic acids. lacceroic acid, melissic acid, montanic acid, and psyllic An additional object of the invention is to provide new acid. Undecenylenic acid, linoleic acid, linolenic acid, and improved chemical compounds wihch are readily erucic acid, ricinoleic acid, and carbocylic monocarboxy adsorbed by metal surfaces and act as corrosion inhibitors. 30 acids of the terpene series, including, for example, abietic Other objects will appear hereinafter. acid and related derivatives such as rosin, polymerized In accordance with the invention, new and improved rosin, dehydrogenated rosin and cracked copals, natu chemical compounds are provided which give new and rally occurring fatty acids, resin acids and petroleum acids improved results in inhibiting corrosion, particularly in (e.g., naphthenic acids) can be employed as the source inhibiting the corrosion of ferrous metals in oil and gas of the monocarboxy acid as well as synthetic acids made well equipment. These compounds can be described as by the oxidation of petroleum. The fatty acids may be compounds from the group consisting of organic poly derived from natural or vegetable sources, for example, carboxy acid amides and salts of an organic monocarboxy lard, cocoanut oil, palm oil, olive oil, corn oil, rapeseed acid amide of an aliphatic polyamine containing at least oil, Sesame oil, cottonseed oil, peanut oil, tallow, sardine two primary amino groups and at least one secondary 40 and fish liver oils. The acids may be employed in the amino group interconnected by carbon atoms in a linear form of primary esters of the glycerides present in such chain, at least one of said primary and secondary amino oils. groups being amidified by at least one carboxyl group of In the preferred practice of the invention at least two said organic monocarboxy acid and at least one of said different types of organic monocarboxy acids are em primary and secondary amino groups being amidified or 45 ployed in acylating the polyamine, one of said monocar converted to a salt by one of the carboxy groups of said boxy acids being a long chain aliphatic monocarboxy acid organic polycarboxy acid, said compound containing both containing at least 8 carbon atoms and the other being a free carboxy groups and free primary and/or secondary carbocyclic monocarboxy acid. One source of mixed amino groups, the said organic monocarboxy acid con acids of this type especially suitable for the preparation taining at least eight carbon atoms, the said organic poly 50 of corrosion inhibitors employed in the practice of the carboxy acid being a polymer fatty acid and containing in - invention is tall oil. excess of 32 carbon atoms, with the further proviso that The organic polycarboxy acids employed for the prepa the molar ratio of the primary and secondary amino nitro ration of corrosion inhibiting compositions useful in the gen of said polyamine to the carboxyl groups of said practice of the invention include, for example, dilinoleic monocarboxylic acid reacted therewith is not greater 55 acid, and other long chain polycarboxy polymer fatty than 5:1 and not less than 2:1 and the molar ratio of the acids or mixtures thereof containing an average of at least remaining primary and secondary amino nitrogen of said two carboxy groups per molecule and preferably con polyamine to the carboxyl groups of said polycarboxy taining at least 32 carbon atoms. acid is not greater than 20:1 and not less than 2:1. The preferred corrosion inhibiting compositions are The initial polyamines which are preferably employed 60 prepared in two stages. In the first stage the polyamine in preparing the corrosion inhibitors of the present in is reacted with the organic monocarboxy acid or a mix vention include, for example, diethylenetriamine, trieth ture of such acids under conditions facilitating the elimi ylenetetramine, tetraethylenepentamine, dipropylenetri nation of Water and the formation of an amide. The amine, tripropylenetetramine, and higher homologues proportions of the organic monocarboxy acids employed thereof, including still residues that remain after the 65 should be at least sufficient to acylate one of the terminal preparation of these materials. These starting materials primary amino nitrogen atoms of the polyamine and can be described generally as polyalkylene polyamines preferably sufficient to acylate both of the terminal pri because they contain two or more alkylene groups sep mary amino nitrogen atoms of the polyamine. In the arated from each other by nitrogen atoms. second stage the resultant monoamide or polyamide, as Another class of polyamines which can be employed as 70 the case may be, is either converted to a salt of a poly starting materials in making corrosion inhibiting composi carboxy acid or further amidified by a reaction with the tions suitable for the practice of the invention are the organic polycarboxy acid. The amount of the organic 3,134,759 e: 4. polycarboxy acid should be such that one of the carboxy tion between the basic amide intermediate and the organic groups of the organic polycarboxy acid acylates a nitro polycarboxy acid will take place at temperatures below gen atom of the polyamine. If both of the primary those where chemically combined water is eliminated. amino groups of the polyamine have been previously The invention will be further illustrated but is not lim acylated by the organic monocarboxy acid, the further ited by the following examples in which the quantities acylation with the polycarboxy acid will occur at the Sec are stated in parts by weight unless otherwise indicated. ondary amino group or groups. In general, the molar ratio of the polycarboxy acid to the unreacted primary Example I and secondary amino nitrogen atoms of the intermediate To a reaction vessel provided with agitation and a amide is preferably not greater than 1:2. O means for removal of an aqueous distillate and the return To illustrate the practice of the invention a monobasic of an azeotrope to the reaction mass there was added ap acid such as tall oil is reacted with a polyamine Such as proximately 5400 parts of crude tall oil, 2670 parts of a triethylene tetramine so that one carboxyl group reacts polyamine having a commercial designation polyamine with at least one primary or secondary amino group leav H special and 2250 parts of a suitable hydrocarbon frac ing one or more unreacted basic primary or secondary tion. Such as SO2 extract. The above reactants were amino groups. This is an intermediate product which heated with agitation until an aqueous distillate began to is herein designated a basic amide intermediate. form. Since there was some contaminating water in the This basic amide intermediate is then reacted with a crude tail oil it was essential that the temperature was relatively small proportion of an organic dicarboxy poly raised very gradually and slowly in order to prevent foam mer fatty acid. The amide formation resulting from the 20 ing and resulting loss of material from the reaction vessel. reaction with a dicarboxy acid and a portion of the un After the temperature reached approximately 150° C. to reacted basic primary or secondary amino groups result in 160° C. most of the foaming problems had ceased and a finished product still containing a basic unreacted pri heating was continued at a customary rate until a total mary or secondary amino group.

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