3,017,356 United States Patent Office Patented Jan. 16, 1962 1. 2 rated aliphatic radical, a cycloaliphatic radical, an aryl 3,017,356 radical, an aralkyl radical, an alkaryl radical, an alkoxy WillianPROCESS B. Hughes, OF andINHIBITING Verner L. Stronberg,CORROSION Webster alkyl radical, an aryloxyalkyl radical, and the like; and Groves, Mo., assignor's to Petroite Corporation, Wii A is an alkylene group; for example, ethylene and propyl mington, Del, a corporation of Delaware ene radicals, such as No Drawing. Original application Mar. 3, 1958, Ser. No. 718,391 Divided and this application Nov. 23, 1959, Ser. No. 854,553 -CH2CH2CH 15 Claims. (C. 252-8.55) CH-CH2 O B This application is a division of Serial No. 718,391, CHs filed March 3, 1958. This invention relates to esters of cyclic amidines of -CH-CH-CH,- the formula gh, CHis O 15 -bH-bH In general, the amidine esters are prepared by reacts o-o-c- ing a hydroxyaliphatic cyclic amidine ()-ROH with less where (A) and (B) are cyclic amidine-containing radicals, than a stoichiometric amount of a polycarboxylic acid to for example, imidazoline and tetrahydropyrimidine radi form a half ester cals (hereafter referred to as “amidine esters'). More 20 particularly, this invention relates to esters wherein. A contains one type of cyclic amidine ring and B contains (a)-R-O C-Z-COH the same or another type not selected in A. This inven which is subsequently reacted with an amidine forming tion also relates to a process of preparing these com polyamine to form the amidine ester pounds which comprises reacting a hydroxy-containing 25 O cyclic amidine with less than a stoichiometric amount of a polycarboxylic acid to form a partial ester and then re Q-R-O-)-2- acting this partial ester with a polyamine capable of form More specifically, the corrosion inhibiting aspect of this ing a second amidine ring of the same or different type. invention relates to a method for inhibiting corrosion of This invention also relates to using these compounds as 30 ferrous metals by hydrocarbon fluids containing water corrosion inhibitors in preventing the corrosion of metals, and corrosive materials such as H2S, CO2, inorganic acids, most particularly steel and ferrous metals. organic acids, etc., combinations of these materials with Heretofore, a wide variety of cyclic amidine com each other, combinations of each of said corrosive ma pounds have been employed to inhibit the corrosion of terials with oxygen, and combinations of said materials oil well equipment. Although we had expected that hy 35 with each other and oxygen, which comprises adding to droxyaliphatic cyclic amidines would also be effective in said fluids at least 5 parts per million of the above inhibiting oil field corrosion, we found that these com amidine esters, said compounds being sufficiently soluble pounds had very poor corrosion inhibiting properties. in the hydrocarbon fluid to inhibit corrosion. However, we have now unexpectedly discovered that THE HYDROXY CYCLIC AMIDINE the derivatives of these hydroxyaliphatic cyclic amidines, 40 The expression "cyclic amidines” is employed in its particularly the amidine esters thereof, are very effec usual sense to indicate ring compounds in which there are tive corrosion inhibitors, in many cases 10 or more times present either 5 members or 6 members, and having 2 as effective as the corresponding hydroxyaliphatic cyclic nitrogen atoms separated by a single carbon atom sup amidine. - 45 plemented by either two additional carbon atoms or three More specifically, in the above formula A and B con additional carbon atoms completing the ring. All the tain either imidazoles or tetrahydropyrimidine radicals, carbon atoms may be substituted. In the present in for example, the following radicals stance, the nitrogen atom of the ring involving two mono (1) valent linkages is substituted with a hydroxy-containing 50 grOllp. These cyclic amidines are further characterized as be ing substituted imidazolines and tetrahydropyrimidines in which the two-position carbon of the ring is generally (2) bonded to a hydrocarbon radical or comparable radical 55 derived from an acid, such as a low molal fatty acid, a high molal fatty acid, or comparable acids, polycarboxy acids, and the like. For details of the preparation of imidazolines substi tuted in the 2-position from amines, see the following 60 U.S. patents, U.S. No. 1,999,989, dated April 30, 1935, Max Bockmuhl et al.; U.S. No. 2,155,877, dated April 25, 1939, Edmund Waldmann et al.; and U.S. No. 2,155,878, dated April 25, 1939, Edmund Waldmann et in which al. Also see Chem. Rev. 32, 47 (43), and Chem. Rev. 65 54,593 (54). Equally suitable for use in preparing compounds of and =C-R-C-F are the residual radicals derived from our invention and for the preparation of tetrahydro the carboxylic acids; pyrimidines substituted in the 2-position are the poly amines containing at least one primary amino group and O g R-C-OH R=(C-OH)2 70 at least one secondary amino group, or another primary where R comprises, for example, a saturated or unsatu amino group separated from the first primary amino group by three carbon atoms instead of being separated 8,017,356 3 4. by only 2 carbons as with imidazolines. This reaction, acids, the hydroxy stearic acids, the hydroxyoctadecenoic as in the case of the imidazolines, is generally carried acids, for example, ricinoleic acid, ricinelardic acid, hy out by heating the reactants to a temperature at which 2 droxyoctadecynoic acids, for example, ricinstearolic acid, moles of water are evolved and ring closure is effected. the hydroxyeicosanoic acids, for example, hydroxy For details of the preparation of tetrahydropyrimidines, arachidic acid, the hydroxydocosanoic acids, for example, see German Patent No. 700,371, dated December 18, hydroxybehenic acid, and the like. 1940, to Edmund Waldmann and August Chwala; Ger Examples of acetylated hydroxyacids comprise ricin man Patent No. 701,322, dated January 14, 1941, to Kark oley lactic acid, acetyl ricinoleic acid, chloroacetyl Kiescher, Ernst Urech and Willi Klarer, and U.S. Patent ricinoleic acid, and the like. No. 2,194,419, dated March 19, 1940, to August Chwala. 0. Examples of the cyclic aliphatic carboxylic acids com Substituted imidazolines and tetrahydropyrimidines are prise those found in petroleum called naphthenic acids, obtained from a variety of acids beginning with the one hydrocarpic and chaulmoogric acids, cyclopentane car carbon acid (formic) through and including higher fatty boxylic acids, cyclohexanecarboxylic acid, campholic acid, acids or the equivalent having as many as 32 carbon fencholic acids, and the like. atoms. Modified fatty acids also can be employed as, for 5 Examples of aromatic monocarboxylic acids comprise example, phenyl stearic acid or the like. Cyclic acids may benzoic acid, substituted benzoic acids, for example, the be employed, including naphthenic acids. A variety of toluic acids, the xyleneic acids, alkoxybenzoic acid, phenyl other acids including benzoic acid, substituted benzoic benzoic acid, naphthalene carboxylic acid, and the like. acid, salicyclic acid, and the like, have been employed to Mixed higher fatty acids derived from animal or vege 20 table sources, for example, lard, cocoanut oil, rapeseed oil, furnish the residue sesame oil, palm kernel oil, palm oil, olive oil, corn oil, RC cottonseed oil, sardine oil, tallow, soyabean oil, peanut oil, castor oil, seal oils, whale oil, shark oil, and other fish from the acid RCOOH in which the C of the residue oils, teaseed oil, partially or completely hydrogenated ani 25 mal and vegetable oils are advantageously employed. Ré Fatty and similar acids include those derived from various is part of the ring. The fatty acids employed, for example, waxes, such as beeswax, spermaceti, montan wax, Japan may be saturated or unsaturated. They may be hydroxyl wax, coccerin and carnauba wax. Such acids include ated or nonhydroxylated. Branched long chain fatty acids carnaubic acid, cerotic acid, lacceric acid, montanic acid, may be employed. See J. Am. Chem. Soc. 74, 2523 30 psyllastearic acid, etc. One may also employ higher mo (1952). This applies also to the lower molecular weight lecular weight carboxylic acids derived by oxidation and acids as well. other methods, such as from paraffin wax, petroleum and Among sources of such acids may be mentioned straight similar hydrocarbons; resinic and hydroaromatic acids, chain and branched chain, saturated and unsaturated, such as hexahydrobenzoic acid, hydrogenated naphthoic, aliphatic, cycloaliphatic, aromatic, hydroaromatic, aralkyl 35 hydrogenated carboxy diphenyl, naphthenic, and abietic acids, etc. acid, aralkyl and aromatic acids, such as Twitchell fatty Examples of saturated aliphatic monocarboxylic acids acids, naphthoic acid, carboxydiphenylpyridine carboxylic comprise: acetic, propionic, butyric, valeric, caproic, acid, blown oils, blown oil fatty acids and the like. heptanoic, caprylic, nonanoic, capric, undecanoic, lauric, Other suitable acids include phenylstearic acid, ben tridecanoic, myriatic, pentadecanoic, palmitic, hepta 40 Zoylnonylic acid, cetyloxybutyric acid, cetyloxyacetic acid, decanoic, Stearic, nonadecanoic, eicosanoic, heneicon chlorostearic acid, etc. sanoic, docosanoic, tricosanoic, tetracosanoic, pentaco Examples of the polycarboxylic acids comprises those sanoic, cerotic, heptacosanoic, montanic, nonacosanoic, of the aliphatic series, for example, oxalic, malonic, suc melissic and the like. cinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, Examples of ethylenic unsaturated aliphatic acids com 45 nonanedicarboxylic acid, decanedicarboxylic acids, unde prise: acrylic, methacrylic, crotonic, anglic, teglic, the canedicarboxylic acids, and the like. pentenoic acids, the hexenoic acids, for example, hydro Examples of unsaturated aliphatic polycarboxylic acids Sorbic acid, the heptenoic acids, the octenoic acids, the comprise fumaric, maleic, mesocenic, citraconic, glutonic, nonenoic acids, the decenoic acids, for example, obtusilic itaconic, muconic, acenitic acids, and the like. acid, the undecenoic acids, the dodecenoic acids, for ex 50 Examples of aromatic polycarboxylic acids comprise ample, lauroleic, linderic, etc., the tridecenoic acids, the phthalic, isophthalic acids, terephthalic acids, substituted tetradecenoic acids, for example, myristoleic acid, the derivatives thereof (e.g. alkyl, chloro, alkoxy, etc. deriva pentadecenoic acids, the hexadecenoic acids, for example, tives), biphenyldicarboxylic acid, diphenylether dicar palmitoleic acid, the heptadecenoic acids, the octodecenoic boxylic acids, diphenylsulfone dicarboxylic acids and the acids, for example, pentrosilenic acid, oleic acid, elardic 55 like. acid, the nonadecenoic acids, for example, the eicosenoic Higher aromatic polycarboxylic acids containing more acids, the docosenoic acids, for example, erucic acid, than two carboxylic groups comprise hemimelitic, tri brassidic acid, cotoleic acid, the tetracosenic acids, and mellitic, trimesic, mellophanic, prehnitic, pyromelitic the like. acids, mellitic acid, and the like. Examples of dienoic acids comprise the pentadienoic 60 Other polycarboxylic acids comprise the dimeric, tri acids, the hexadienoic acids, for example, sorbic acid, the meric and polymeric acids, for example, diricinoleic acid, octadienoic acids, for example, linoleic, and the like. triricinoleic acid, polyricinoleic acid, and the like. Other Examples of the trienoic acids comprise the octadec polycarboxylic acids comprise those containing ether atrienoic acids, for example, linolenic acid, eleostearic groups, for example, diglycollic acid. Mixtures of the acid, pseudo-eleostearic acid, and the like. 65 above acids can be advantageously employed. Carboxylic acids containing function groups such as In addition, acid precursors such as esters, acid chlo hydroxy groups can be employed. Hydroxy acids, par rides, glycerides, etc. can be employed in place of the ticularly the alpha hydroxy acids comprise glycolic acid, free acid. lactic acid, the hydroxyvaleric acids, the hydroxy caproic Where the acid contains a functional group, for exam acids, the hydroxyheptanoic acids, the hydroxy caprylic 70 ple, a hydroxy group, this should be taken into considera acids, the hydroxynonanoic acids, the hydroxycapric acids, tion in calculating the stoichiometry of the subsequent the hydroxydecanoic acids, the hydroxy lauric acids, the acylation. hydroxy tridecanoic acids, the hydroxymyristic acids, the Hydroxy substituted imidazolines and tetrahydropyrimi hydroxypentadecanoic acids, the hydroxypalimitic acids, dines can be obtained in the manner described above the hydroxyhexadecanoic acids, the hydroxyheptadecanoic 75 from a wide variety of polyamines containing hydroxy 3,017,356 5 6 groups. Thus, where one starts with a polyamine, for rate the water and to continuously return xylene to the example, a diamine of the following formula reaction mixture. Reflux is continued at a temperature EI of 160-170° C. for about 32 hours until about 2 moles NH.R-N-R-OH or NH-R-N-(OR), H. of water are removed. The product is where R has for example 2 or 3 carbons in its main chain one obtains the compounds of this invention. In NSH-H, N-CHCHOH addition, one can start with ethylene diamine or with 1,2- propylene diamine, 1,3-propylenediamine or other poly S/ amines and then react the cyclic amidine so obtained with alkylene oxides so as to produce a terminal hydroxy 0. Example 9b group since the nitrogen bonded hydrogen on the 1-posi tion on the ring reacts with alkylene oxides. Polyoxy The above example is repeated except that hydroxy alkylated cyclic amidines can be prepared by reacting a ethylpropylene diamine 1-3, hydroxyalkylcyclic amidine with an alkylene oxide. Alkylene oxides comprise those of the general formula 5 HO CHCH.-CHCHCHNH, R-CH-CH is employed in place of hydroxyethylethylene diamine and stearic acid is employed in place of oleic acid. The Yo/ product produced is where R is an alkyl group. Among the alkylene oxides that may be employed are ethylene, propylene, butylene, 20 CH octylene, etc., oxides. Other oxyalkylation agents such off, YoH, as glycide, epichlorohydrin, etc., can be employed. N N-CH.CHOH Thus, compounds within the scope of this invention N / which react with polycarboxylic acids comprise com C pounds of the formulae: 25 Critis Example 4c The process of Example 10a is repeated with the same amine 30 HO CHCHNCHCHN (2 moles) and a polycarboxylic acid, sebacic acid (1. mole). Instead of two moles of water being removed, 35 as in the prior example, 4 moles of water are removed. The product is where (H-H, gh-H, HO-CEI-CH-N N N N-CH2CHOH RC 2 N/ 40 C-(CH2)8-C is the residue derived from the carboxylic acid, where R is a hydrocarbon radical having, for example, up to Example 20d about 32 carbon atoms, hydrocarbons in which the carbon The process of Example 4c is repeated with atom chain is interrupted by oxygen, etc., n is 2 or 3; B is HOCH2CH2NCHCHCHNH a hydrogen or a hydrocarbon radical, for example, an alkyl radical; and D is a hydroxy-containing radical, for 45 h example, -ROH or -(RO)H, wherein n is a whole (2 moles) and a polycarboxylic acid, terephthalic acid number, for example, 1-10 or higher, but preferably (1 mole). As in the prior example, 4 moles of water 1-5, and CB2 is, for example, a divalent radical of the are removed. The product is CE CH formula -CH2CH2-, -CH-CH-CH2-, 50 -CH-CH-, -CH-CH- -CH-CH-CH, etc. off, Yoh, c?, Yoh, ÖH, ÖH, &H, CH EIO CH-C Hi-N N N N-o HCHO In general, the hydroxy alkyl cyclic amidines are pre Yo1 ( Y/ pared by reacting a polyamine containing a terminal al kanol group with a carboxylic acid at temperatures of 55 In general, to form the polyoxyalkylated hydroxy cy from 150-175 C. employing an azeotroping agent such clic amidines, the hydroxyalkylcyclic amidine is first pre as xylene to remove water. The reaction time of 3-4 pared in the manner shown above and then reacted with hours is employed. Completion of reaction is judged alkylene oxides by the conventional manner of oxyalkyla by the separation of 2 moles of HO for each carboxylic tion using a jacketed stainless steel autoclave in the man acid group. 60 ner described in U.S. Patent 2,792,369 to the desired de Since the preparation of cyclic amidines is so well gree of oxyalkylation, The following examples are illus known, (see above cited patents), it is not believed that trative: any examples are necessary to illustrate such a well known Example lla procedure. However, for purposes of illustration the fol One mole of lowing are included: 65 Example 10a N N-CHCHOH A solution of 1 mole of hydroxyethyl ethylene diamine, S/ HO CHCHNCHCH-NH, 70 &H H (50% solution in xylene) is reacted with 1 mole of ethyl and 1 mole of oleic acid in 300 grams of xylene are ene oxide at a temperature of 125-130° C. and a pres charged to a flask and brought to reflux, the mixture being sure of 10-15 p.s. i. The time regulator is set to add heated under a Dean Stark water trap condenser in order ethylene oxide over 4 hour followed by additional stir to distill off the water-xylene azeotrope mixture, to sepa 75 ring for another 2 hour to insure complete reaction.

8,017,356 9 10 TABLE IV cyclic amidine group having at least one ester side-chain. The

C-OH of the formula indicates the product is a partial ester having at least one free carboxylic acid group. Ex. No. HOOC-R-COOH source R Thus, the products of this invention may be illustrated of-CRC with dicarboxylic acids as follows: O ld------Phthalie.------CH2CH2OH. 2d. Succinic. CH2CH2OH 3d- Glutaric CH2CH2OH. 4.d.-- Adipic- CHCHOF 5d.-- Suberic (CH) CHCH3OH 6d------Sebacic CH2CH2OH 7d.------Pimelic- CH2CHOCH2CH2OH 5 8d.------Azelaic------CH2CH2OH where X includes a 9d. Nonodecane dicarboxylic------CH2CH2OH. 0d. Eicosanedicarboxylic CH2CH2OH 11d. Diglycolic------CH2CH2OH. g 12d Ethylene bis(glyco (CH3)CHCH2OH -R'-O-C-, -(R'O)-C- 3d Methylenedicarboxylic acid.-- (CH3)CHCH2OH 14d.------Dilinoleic------CH2CH2OH etc. group and Z is the radical derived from the poly 15d.------Steary malonic--- CECHOH 20 carboxylic acid. 16d Lauryl Succinic------C2CH2OH. 17d. Isotetradecyl succinic CH2CH2OH. In the case where bicyclic amidine compounds are 18d. Phthalic---- CH2CH2OCH2CH2OH 19d. Isophthalic--- CH2CH2OH. used as hydroxy precursors, the following partial esters 20d.- Terephthalic- CH2CH2OH are formed wherein X and Z have the meanings of the 21d------Glutaconic--- CHCHOF preceding formula: Sebacic------CEICH2OH 25 THE POLYCARBOXYLIC ACIDS The polycarboxylic acid employed to react with the hydroxycyclicamidine can be varied widely. In general, 30 they can be expressed as where Z comprises a saturated or unsaturated aliphatic 35 To insure the presence of a terminal carboxyl group radical, a cycloaliphatic radical, an aromatic radical, and on the bicyclic amidine, one employs a partial ester of the like, and X is a whole number equal to 2 or more, the polycarboxylic acid or the acid anhydride under mild for example, 2-4, but preferably 2. conditions, or the like, and then reacts this product with Examples of the polycarboxylic acids comprise those 40 the appropriate diamine to form an amidine group. of the aliphatic series, for example, oxalic, malonic, suc Since the hydroxy precursor in the case of the bicyclic cinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, amide is bifunctional (i.e., has two. hydroxy groups), and nonanedicarboxylic acid, decanedicarboxylic acids, un the polycarboxylic acid is also polyfunctional, polyesters decanedicarboxylic acids, and the like. might otherwise be formed. However, these polyesters Examples of unsaturated aliphatic polycarboxylic acids are also useful in further reaction according to the present comprise fumaric, maleic, mesoconic, citraconic, glutonic, 45 invention provided they are partial esters (i.e., have at itaconic, muconic, aconitic acids, and the like. least one free carboxylic acid group), and are soluble in Examples of aromatic polycarboxylic acids comprise well fluids. phthalic, isophthalic acids, terephthalic acids, substituted The following examples are illustrative of the prepara derivatives thereof (e.g. alkyl, chloro, alkoxy, etc. deriva tion of partial esters. Two moles of carboxylic acid tives), biphenyldicarboxylic acid, diphenylether dicarbox 50 radicals are employed for each mole of hydroxy group. ylic acids, diphenylsulfane dicarboxylic acids and the like. Example 10aB Higher aromatic polycarboxylic acids containing more than two carboxylic groups comprise hemimellitic, trimel One mole of the product of Example 10a and 1 mole litic, trimesic, mellophanic, prehnitic, pyromellitic acids, of sebacic acid are dissolved in 300 g, of xylene and the mellitic acid, and the like. 55 reaction mixture, heated to reflux, is azeotroped, using Other polycarboxylic acids comprise the dimeric, a Dean-Stark trap in the manner of Example 10a, until trimeric and other poly acids, for example, dilinoleic acid, one mole of water is removed. The temperature is trilinoleic acid, polylinoleic acid, and the like such as maintained at 150-175° C. and the time is 5 hours. The those prepared by Emery Industries. Other polycarboxy product is lic acids comprise those containing ether groups, for ex 60 ample, diglycolic acid. Mixtures of the above acids can GH-H, 9 be advantageously employed. N N-OHCH,06-(CH), -on In addition, acid precursors such as esters, anhydrides, N/ glycerides, etc. can be employed in place of the free acid. 65 C138 THE PARTIAL ESTER PRODUCTS Example 10aC The products of this invention are partial esters of The process of the prior example is repeated except cyclic amidines. They may be expressed by the follow that terephthalic acid is employed in place of sebacic ing general formula: 70 acid. The product is CH-CH O . N N-CHCHO (-()-d O N/g wherein A comprises a molecule containing at least one 75 CEiss 3,017,356 Example 10aid mole of dicarboxylic acid is employed for each mole of The above example is repeated employing 1 mole of hydroxy group present, (H-H, TABLE W N N-CICHOH 5 S/ Partial Esters

s &H, w O o 2A.a.A.--- SESebacic 23. SSESebacic and 1 mole of dimeric--- (dilinoleic) acid to yield 0 E.a.A.-- TEthalicipic 2RB.c.A. SRai:Succinic (as anhydride hydride) GH gii, 3. Sith l 4cB-...- Tipai, (as mono N S N-CFICHO-C-2- CHO-C-2-COOH 10a).a C- TerephthalicDillinoleic 6cA-- Succinicuty ester(as anhydride) C 10aB. Succinic 6cB--- Pinelic (as monobutyl 13aA- Sebacic ester) C17H33 13aB- Adipic 6cC--- Adipic (as monobutyl d ls -- Superie ester) where Z is the dilinoleic acid residue. 15aB. Dillinoleic 14cA-- Succinic (as anhydride) 5.24a B-. fE,Isophthalic 23c.A.SR: SE:Succinic (as AES3anhydride Example 9b.A. 28a.A. Diglycolic 23cB. Phthalic (as anhydride) th Th ES S of thee ab ove examplele iis1S repeatedDea d excepXcept SERIAE9bB.-- SebacicAdipic 8dB:::A; -- AdipicSebacic SAE;3 (as(as anhydride anhydride) at 1 Imole O 20 9bC - Terephthalic cá,C YoH, THE DIAMIDINEESTERS N N /N-CHCEOE 2 The diamidinea esters are prepared by reactingO the par ( tial ester (or the partial ester having the reactive car C1E35 boxylic group protected with an ester of a low boiling is reacted with 1 mole of adipic acid. imidazolinesalcohol), with are the formed desired by diamine. reacting aAs carboxylic stated above, acid The product CHis 30 with polyamines containinga at least one primaryo amino ? N group and at least one secondary amino group or an CH CE O O other primary group separated from the first primary N N-CHCHO-3-(CH)-on amino by 2 carbons, whereas tetrahydropyrimidine is S/ formed by reacting the partial ester with the correspond ing polyamine containing 3 carbon atoms. This reaction C1H85 8 is carried out until 2 moles of water are removed for Example 4ca each carboxylic acid group. These compounds are in essence "cyclic amidine esters” formed from a cyclic ami To one mole of dine alcohol and a cyclic amide carboxylic acid. Thus, (Hi-H, SH-H, 4. they are in essence the theoretical product of the reaction Hochsch-N c6-(CH).N N. So N-CHCH or O O is added 2 moles of succinic anhydride over a period of Q-X-H--H-O-C-Z-3) - Q-X-C-Z-6) product4 hour, is the addition being carried out at 50 C. The 45 where X comprises -RO, -(RO) etc. and Z is the

HOC(CH2)-COCHCH-N9 (H.-H. N NH.-H. i-CHCH-O--(CH) to H N2 S / Example 28a.A. residual group derived from the carboxylic acid. They The process of Example 9bA is repeated except that may also be expressed by the formula 1 mole of A. O N CE * CE on CHO)3H 35 NC Y-x-E-z-of2 Ye n/ 2V3 So/ Y/ C R Y 1733 and 1 mole of diglycolic acid are employed. The prod- 60 where R, X, and Z have the meanings stated above, and uct is A and B, which may be the same or different, have a main C-CH O O chain of 2 or 3 carbons, and Y, which is the residual N N-(CHCH o)-5- C-O-CI- OE group, comprises hydrogen, a hydrocarbon group. S.s/ 65 &Hs -CE-NR1-R1, -CH2nNEC-R1, -o-Hi-O--R, The above examples are typical methods of preparation. O The following partial esters are prepared by these meth- . . -CH2n-OR1,-(Chan-NR).R. ods. The c and d series are prepared by the use of the half ester of the dicarboxylic acid or with the anhydride. 70 another cyclic amidine group, etc. wherein R1 comprises Each partial ester will have the basic number shown in hydrogen, hydrocarbon groups, etc. and n is 1-6 or higher. the prior tables, for example, 1a, 10a, etc., indicative of Examples of Y comprise ethylene amino groups, hy the hydroxy cyclic amidine employed. In addition, it will droxyethyl amino groups, aminoalkyl groups, alkylene bear the letter A, B, etc., which indicates that it has oxyalkyl groups, hydrocarbon groups, such as alkyl, cy been acylated to a partial ester. In each example one i5 cloalkyl, aralkyl, alkaryl, etc. 8,017,356 13 4. Where the bicyclic amidines are used as hydroxy pre be employed. Many are disclosed in the section of this cursors, the following compounds are formed: specification which discusses the preparation of cyclic amidines. However, it might be mentioned that the N AY-x-5-z-c? N Y preferable polyamines are those which form cyclic am N / Y 5 idines where Y is hydrogen, a radical of the N series, or N-alkylated derivatives of this polyalkylene 2 N. amine series. Examples of polyamines which can be B 10 used in producing the amidine esters can be found in the YN/ Blair and Gross Reissue Patent No. 23,227 (which is y herein incorporated by reference) and in other publica having the same meaning as in the prior formula. tions and patents disclosing amidine-forming polyamines. Thus, where imidazoline of Example 4a An example of suitable amines is found in the "Duo 15 meens' of Armour Chemical Division described in their booklet. They are compounds of the formula N-CHCHOH s/ where the R's are derived from fatty acids: Duomeen 12 20 from lauric acid, Duomeen C from coconut, Duomeen S is reacted with one mole of adipic acid, one obtains the from soya and Duomeen T from tallow. partial ester The R group of Duomeen 12 is composed of dodecyl 95%, decyl 2%, tetradecyl 3%; Duomeen C, octyl 8%, decyl 9%, dodecyl 47%, tetradecyl 18%, hexadecyl 8%, O O octadecyl 5%, octadecenyl 5%; Duomeen S, hexadecyl NN/ N-CHCH-O-(-CH-C-OH 20%, octadecyl 17%, octadecenyl 26%, octadecadienyl 37%; Duomeen T, tetradecyl 2%, hexadecyl 24%, octa C17H33 decyl 28%, octadecenyl 46%. The following examples are presented to illustrate the This partial ester is then reacted with a polyamine capa 30 preparation of the amidine esters. These are prepared in ble of forming an imidazoline or a tetrahydropyrimidine the manner described for preparing the hydroxyalkyl ring, for example, a 1,3-propylenediamine, etc. Thus, cyclic amidines. where the partial ester is reacted with Example 10aB C.HCH, CHCH-NH, 35 One mole of the partial ester produced in Example one obtains a mixed amidine ester 10aA is added to a xylene solution of 1 mole of pro pylene diamine (50% solution by weight) in a reaction - in- O N flask. The reaction mixture is brought to reflux as the N N-CH2CH2O C-CH reaction mixture is heated under a Dean-Stark trap con N / N 40 denser to distill of the water-xylene azeotropic mixture C to separate the water and to return xylene to the reaction (His C1sh:7 mixture. Reflux is continued at a temperature of 150 On the other hand, where the alcoholic moiety of the 175 C. for about 4 hours until about 2 moles of water mixed amidine is prepared from N-hydroxyethyl 1,3-pro are removed. The product is panediamine reacted with lauric acid 45 O

N N-CECH-OH N c^ 50 C118 Example 10aB which is then reacted with one mole of terephthalic acid The above example is repeated employing 10aA and to yield: NHCH2CH2N-CHCHNB- H - r - 55 The product is N / O N C -CHCH-O--(>-3-oh N N-CHgCEIO-C-(CH) s-C2N bha 60 no/ NN This then reacted with: C1E33 bH, CHNB, C Ha-N-CH, CH-NH. Example 10aC to yield a mixed amidine ester of the formula: The prior example is repeated employing the product 65 of 10aC and "Duomeen S" (Armour Co.), O w N | 2 R-N-CHCHNH N - CHCHO-C - - c{ the R group is derived from soya, C N The product formed is CH28 C13 70 O N By varying the polyamines the amidine rings can be | 2 varied. Since the polyamine capable of forming cyclic N N-CH2CHO-C- -C amidines with carboxylic acids is so well known, it is N g / NN unnecessary to state in detail all the polyamines that can 75 C17H33 R

8,017,356 5 6 Example 9b.A. USE AS CORROSION INHIBITOR The process of the prior example is repeated employing More specifically, this phase of the invention relates to the product of 9bA and Amine ODT (Monsanto Chemi the inhibition of corrosion in the petroleum industry with cal), specific reference to producing wells, pipe lines, refineries, B 5 tank storage, etc. C.H.N-C.H.N-C.H.N.H. The use of a corrosion inhibiting agent in the oil industry The product is and other industries, and particularly for the protection of ferrous metals, is well known. For example, see U.S. O -N 10 Patents Nos. 2,736,658, dated February 28, 1954, to N N-CHCHO-C-(CH2)4-C Pfohl et al., and 2,756,211, dated July 24, 1956, to Jones, N c^ NN and 2,727,003, dated December 13, 1955, to Hughes. H More specifically then, and particularly from the stand C1735 CHAN-C 1225 point of oil production, this aspect of the invention relates Example 4cA to inhibiting corrosion caused by hydrogen sulfide, carbon The process of the prior example is repeated employ-l dioxide, inorganic acids, organic acids, combinations of ing the product of 4cA and each with oxygen, and with each other and oxygen. More particularly, it relates to treating wells to mitigate metal Duomeen T (Armour Co.), R derived from tallow. The corrosion and associated difficulties. product is 20 It should also be pointed out that the corrosiveness of

O NS O 2 N. N N-CFICEOC-(CH2)C k 3(OH),éoon.ch, N S NN R k Example 28a.A. oil well brines will vary from well to well, and the propor The process of the prior example is repeated employ tion of corrosion inhibiting agent added to the well fluids 30 should also be varied from well to well. Thus, in some ing the product of Example 28aA and Duomeen T. The wells it may be possible to effectively control corrosion by product is the addition of as little as 5 p.p.m. of our new composi tions to the well fluids, whereas in other wells, it may be necessary to add 200 p.p.m. or more. In using our improved compositions for protecting oil well tubing, casing and other equipment which comes in The above examples are typical methods of prepara contact with the corrosive oil-brine production, we find tion. The following amidine esters are prepared by these that excellent results may be obtained by injecting an methods. 40 appropriate quantity of a selected composition into a TABLE VI producing well so that it may mingle with the oil-brine Amidine Esters mixture and come into contact with the casing, tubing, pumps and other producing equipment. We may, for Ex. Polyamine example, introduce the inhibiting composition into the 2aA------Propylenediamine 4a.A.------Dipropylenetriamine top of the casing, thus causing it to flow down into the 45 well and thence back through the tubing, etc. In general, 10aA1------NEI(CH2)3.N-CHCHOH we have found that this procedure suffices to inhibit H corrosion throughout the entire system of production, and 10aA2------NH(CH2)N-CH2CH2OH. collection, even including field tankage. Propylenediamine In case serious emulsion or gel problems are encoun Diethylenetrianine 50 Duomeen-S tered, demulsifiers may be added. This is important not Duomeen T only to avoid the troublesome emulsions and gels them Dipropylenetriamine selves, but also to improve corrosion inhibition. The explanation of less effective corrosion inhibition in the C.H.-N-(CH) 3N-CCHO 55 presence of emulsions apparently is that the inhibitor is Dipropyledetrial nine somewhat surface-active. That is, it is concentrated at Duomeen S interfacial surfaces. Since this surface is great in an TriethylenetetramineDuomeen T 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 Diethylenetrianine wells the inhibitors, herein described tending to form B. water-in-oil type emulsions, often decrease the emulsion NH3(CH2)N-CHCHOH problems naturally present. Thus, in addition to being Triethylenetetrainine 65 effective corrosion inhibitors, the herein described prod ucts tend to eliminate emulsion problems which some times appear when some of the present day inhibitors are used in oil wells or refinery processing. Duomeen T The method of carrying out our process is relatively DomeenDipropylenetriamine S 70 simple in principle. The corrosion preventive reagent is Duomeen DuOIneen S dissolved in the liquid corrosive medium in small amounts Eduomeen T and is thus kept in contact with the metal surface to be 8dA1------C.Hi-N- CH2)3.NE protected. Alternatively, the corrosion inhibitor may be 75 applied first to the metal surface, either as is, or as a solu

8,017,356 17 18 tion in some carrier liquid or paste. Continuous applica the like, in numerous instances the effectiveness of the tion, as in the corrosive solution, is the preferred method corrosion inhibitor thus obtained is often significantly however, greater than the use of either one alone. The present process finds particular utility in the pro Since these products are basic, they can be combined tection of metal equipment of oil and gas wells, especially with various acids to produce salts in which oil solubility those containing or producing an acidic constituent such is increased or decreased. Likewise, water solubility may as H2S, CO2, organic acids, O2 and the like. For the be increased or decreased. For instance, the products protection of such wells, the reagent, either undiluted or may be mixed with one or more moles of an acid, such dissolved in a suitable solvent, is fed down the annulus as higher fatty acids, dimerized fatty acids, naphthenic of the well between the casing and producing tubing 10 acids, acids obtained by the oxidation of hydrocarbons, where it becomes commingled with the fluid in the well as well as sulfonic acids such as dodecylbenzene sulfonic and is pumped or flowed from the well with these fluids, acid, petroleum mahogany acids, petroleum green acids, thus contacting the inner wall of the casing, the outer and etc. inner wall of tubing, and the inner surface of all well What has been said in regard to the acids which in head fittings, connections and flow lines handling the 15 corrosive fluid. crease oil solubility and decrease water solubility applies Where the inhibitor composition is a liquid, it is con with equal force and effect to acids of the type, such as ventionally fed into the well annulus by means of a motor acetic acid, hydroxyacetic acid, gluconic acid, etc., all of driven chemical injector pump, or it may be pumped which obviously introduce hydrophile character when periodically (e.g., once every day or two) into the 20 they form salts or complexes, if complexes are formed. annulus by means of a so-called "boll weevil' device or For example, any of the acids described above to pre similar arrangement. Where the inhibitor is a solid, it pare the cyclic amidines are useful in preparing these may be dropped into the well as a solid lump or stick, salts. it may be blown in as a powder with gas, or it may be 25 As pointed out previously, the addition of corrosion washed in with a small stream of the well fluids or other inhibitors, particularly in the form of a solution by means liquid. Where there is gas pressure on the casing, it is of a metering pump or the like, is common practice. The necessary, of course, to employ any of these treating particular corrosion inhibitors herein described are ap methods through a pressure equalizing chamber equipped plied in the same manner as other corrosion inhibitors to allow introduction of reagent into the chamber, equali 30 intended for use for the same purpose. For sake of zation of pressure between chamber and casing, and travel brevity, one may use the corrosion inhibitor in solution of reagent from chamber to well casing. form by dissolving it in a suitable solvent such as mineral Occasionally, oil and gas wells are completed in such a oil, methyl ethyl ketone, xylene, kerosene, high boiling manner that there is no opening between the annulus and aromatic solvent, or even Water. the bottom of the tubing or pump. This results, for ex 35 The following examples are presented to illustrate the ample, when the tubing is surrounded at some point by a superiority of the instant compounds as corrosion packing held by the casing or earth formation below the inhibitors. casing. In such wells the reagent may be introduced into the tubing through a pressure equalizing vessel after stop 40 STIRRING TESTS ping the flow of fluids. After being so treated, the well should be left closed in for a period of time sufficient to These tests are run on synthetic fluids. The procedure permit the reagent to drop to the bottom of the well. involves the comparison of the amount of iron in solu For injection into the well annulus, the corrosion inhibi tion after a predetermined interval of time of contact of tor is usually employed as a solution in a suitable solvent, 45 a standardized iron surface with a two-phase corrosive such as mineral oil, methylethyl ketone, xylene, kerosene, medium with similar determinations in systems containing or even water. The selection of solvent well depend much inhibitors. upon the exact reagent being used and its solubility char Six hundred ml. beakers equipped with stirrers and acteristics. It is also generally desirable to employ a heaters are charged with 400 ml. of 10% sodium chlo solvent which will yield a solution of low freezing point, 50 ride containing 500 p.p.m. acetic acid and 100 ml. of so as to obviate the necessity of heating the solution and mineral spirits. The liquids are brought to temperature injection equipment during winter use. and a 1 x 1 inch sand blasted coupon is suspended by For treating wells with packed-off tubing, the use of means of a glass hook approximately midway into the solid “sticks' or plugs of inhibitor is especially conven 55 liquid phase of the beaker. The stirrer is adjusted to agi ient. These may be prepared by blending the inhibitor tate the liquids at such a rate as to provide good mixing with a mineral wax, asphalt or resin in a proportion Sufi of the two layers. cient to give a moderately hard and high-melting solid After 30 minutes samples of the aqueous phase are which can be handled and fed into the well conveniently. taken and the iron content of each sample is determined The amount of corrosion preventive agent required in 60 by measuring the color formed by the addition of hydro our process varies with the corrosiveness of the system, chloric acid and potassium thiocyanate in a photoelectric but where a continuous or semi-continuous treating pro colorimeter. cedure is carried out as described above, the addition of The protection afforded by an inhibitor is measured by reagent in the proportion of from 5 parts per million to comparison of the amount of light absorbed by inhibited 1000 parts per million or more parts of corrosive fluid 65 and uninhibited samples run simultaneously. Percent will generally provide protection. protection can be determined by the following formula: These corrosion inhibitors can be used in combina tion with other well-known corrosion inhibitors, for ex ample, the cyclic amidine structures, the amido cyclic 70 six 100 = percent protection amidine structures, and the amino cyclic amidine struc 1. - tures, 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 where A, is the present light absorbed by an uninhibited in the ratio of one-to-three, one-to-one, three-to-one, or 75 sample and A is the same value for an inhibited sample.

3,017,356 20 TABLE WII TABLE VIII Static Weight Loss Test Hot Stirring Test (140°F.) Inhibitor Concentration, 100 p.p.In. Inhibitor Concentration, 40 p.p.m. O N-CH 2 N 9 N-c N -CH-CH.0 c-R-cy oH, N -CH-CHO &-R-c? CH, Sc N-CE S C Y-c?, k kn k k" O Percent R R R pro tection Percent R R Rev pro tection C17H33------(CH2)4------Duomeen T- 80, 5 C17H3S------(CH2)4------Duomeen T- 88 C17H33------–{ X- - do------93.0 C17H33------(CH2)8------do------90.6 C17H3------{X- - do------92 C 7H33------(CH2)4------C12H2S------93. 6 Ciss------(CH2)8------do------86 20 C17H33------(CH2)4------C12H25------9. C5H11------( >- Duomeen T--- 8.2 CHil------( >- Duomec T 9. C5H11------(CH2)8------do------94.5 C5H11------(OH)8------do------84 25 CH13------{ X- - - - - do------93.8 CHi------–{ X- - - - do------87 N N-CH2CH2OH ------20,0 N/ N NCHCH-OH ------10 30 g S C17H33 C ths OTHER USES 35 These products are effective not only as corrosion in hibitors but can be used for a number of other purposes. For instance, they can be used as asphalt additives to increase the adhesiveness of the asphalt to the mineral ag STATIC WEIGHT LOSS TESTS gregates. In the form of water soluble salts, they are 40 useful as bactericides in the secondary recovery of oil. The hydroxycyclic amidines may be subjected to extensive These tests have been run on both synthetic and natural oxyalkylation by means of ethylene oxide, propylene occurring fluids. The test procedure involved the measure oxide, butylene oxide, or the like prior to reaction ac ment of the corrosive action of the fluids inhibited by the cording to this invention. These are oxyalkylated and compositions herein described upon sandblasted. S.A.E. 45 still have oil solubility as, for example, by the addition 1020 steel coupons measuring 78 x 34 inches under of propylene oxide or butylene oxide, or are oxyalkylated conditions approximating those found in an actual pro to produce water solubility as, for example, by means of ducing well, and the comparison thereof with results ethylene oxide or glycide. They are also oxyalkylated by obtained by subjecting identical test coupons to the cor combinations of propylene oxide and ethylene oxide so rosive action of identical fluids containing no inhibitor. 50 that both water solubility and oil solubility remain. Clean pint bottles were charged with 200 ml. of 10% Thereupon they are reacted with the polycarboxylic acids sodium chloride solution saturated with hydrogen sulfide and polyamines. Such products are useful for a variety and 200 ml. of mineral spirits and a predetermined of purposes and particularly for those where nonionic amount of inhibitor was then added. In all cases the surfactants or sequestered cationic surfactants are indi inhibitor concentration was based on the total volume 55 cated. of fluid. Weighed coupons were than added, the bottles In addition, the compounds of this invention have the tightly sealed and allowed to remain at room temperature following uses: for 3 days. The coupons were then removed, cleaned Agriculture: kerosene, phenothiazine, pyrethrum sprays, by immersion in inhibited 10% hydrochloric acid, dried fungicides, herbicidal oils. and weighed. 60 Anti-static treatment: for hotel rugs, hospital floors, The changes in the weight of the coupons during the automobile upholstery, plastic and wax polishes, wool corrosion test were taken as a measurement of the effec oils, lubricants for synthetic fibers. - tiveness of the inhibitor compositions. Protection per Building materials: water repellent treatment for centage was calculated for each test coupon taken from plaster, concrete, cement, roofing materials, air entrain the inhibited fluids in accordance with the following ment, floor sealers, linoleum. formula: Cosmetics: formulation of anti-perspirants, deodorants, sun screens, hair preparations. De-emulsifying: in antibiotic extraction, breaking crude X 100 = percent protection oil- and water-gas for emulsions. 70 Detergents: metal cleaning emulsions, lens cleaners, floor oils, dry cleaning detergents, radiator flushes, cess in which L is the loss in weight of the coupons taken pool acid, boiler scale solvents, germicidal corrosion-in from uninhibited fluids and La is the loss in weight of hibited acid detergents for dairies, enamel equipment, coupons which were subjected to the inhibited fluids. 75 toilet bowls,

8,017,856 21 22 Leather: Flat liquoring oils, pickling, acid degreasing, fluid characterized by treating said metals with a com dye fixative. pound of the formula: Metals: rust preventive oils, cutting oils, water dis placing compounds, pickling inhibitor, solvent degreasing. (CB) 2-3 O N Paints: for improved adhesion of primers, preventing 5 - 2 water spotting in lacquers, anti-skinning, pigment flush N --to-2-c, ( B)-3 ing, grinding and dispersing, anti-feathering in inks. s N Petroleum: germicide in flood water treatment, de R Y emulsifying fuel oil additives, anti-strip agent in asphalt emulsions and cutbacks. O where R' is lower alkylene and R, Z and Y are hydro Textiles: in rubberizing, textile oils, dyeing assistants, carbons having 1-30 carbon atoms. softening agents. 6. The process of claim 5 where the compound con Miscellaneous: bentonite-amine complexes, metal tains both an imidazoline and a tetrahydropyrimidine ring amine complexes, preparation of pentachlorphenates, in the ring structures of said formula. quaternaries, plastisols, and rodent repellents. 5 7. The process of claim 5 where R is -CHCH-. Having thus described our invention, what we claim 8. The process of claim 6 where R is -CHCH-. as new and desire to obtain by Letters Patent is: 9. A method of inhibiting corrosion of ferrous metals 1. A method of inhibiting corrosion of ferrous metals employed in conjunction with a corrosive hydrocarbon employed in conjunction with a corrosive hydrocarbon fluid characterized by treating said metals with a com fluid characterized by treating said metals with a com 20 pound of the formula pound of the formula: N (CH2)- O N top- O a - visis-- a (CB)-3 N N-CEC-O-C-(CE)--C (CH2)-s s g - N Y R y N-r where R and Y are hydrocarbons containing 5-30 carbon a b 22-3) atonS. -(CB)-- NN 30 10. The process of claim 9 where the compound con tains both imidazoline and tetrahydropyrimidine rings in Y 0-1 the ring structures of said formula. where B is selected from the group consisting of hydrogen 11. A method of inhibiting corrosion of ferrous metals and lower alkyl, R' is lower alkylene, R and Z are non 35 employed in conjunction with a corrosive hydrocarbon carboxylic residues of carboxylic acids, and Y is a residue fluid characterized by treating said metals with a com of a polyalkylene polyamine. pound of the formula 2. A method of inhibiting corrosion of ferrous metals (CI)-3 O N employed in conjunction with a corrosive hydrocarbon 2 fluid characterized by treating said metals with a com 40 pound of the formula: S- -otch-o-3-(D-c{N r g N R Y

45 where R and Y are hydrocarbons containing 5-30 carbon atOS. Y 12. The process of claim 11 where the compound con N. tains both imidazoline and tetrahydropyrimidine rings in a N-RO-C-Z-C (C2)3-3 the ring structures of said formula. 13. A method of inhibiting corrosion of ferrous metals 50 employed in conjunction with a corrosive hydrocarbon y 0-1 fluid characterized by treating said metals with a com where R' is a lower alkylene containing 2-4 carbon atoms pound of the formula and R, Z and Y are hydrocarbons containing 1-30 car 55 bons. O 2N 3. The method of claim 2 where the compound con N N-CHCH-O-C-(CH2)-10-C tains both an imidazoline and a tetrahydropyrimidine S/ NN ring in the ring structures of said formula. g 4. A method of inhibiting corrosion of ferrous metals CHss R employed in conjunction with a corrosive hydrocarbon 60 fluid characterized by treating said metals with a con where R is a tallow-derived hydrocarbon. 14. A method of inhibiting corrosion of ferrous metals pound of the formula: employed in conjunction with a corrosive hydrocarbon (CB 2) - O N fluid characterized by treating said metals with a com - 2 1- 2 35 N N-(RO)-10-C-Z-C (CB) - pound of the formula: S N C N R Y O 2N N N-CHCH-O-C-(CH)-o-C where B is selected from the group consisting of hydrogen 70 S / NN and lower alkyl, R is lower alkylene, R and Z are non C carboxylic residues of carboxylic acid, and Y is a residue &nha C15 of a polyalkylene polyamine. 5. A method of inhibiting corrosion of ferrous metals 15. A method of inhibiting corrosion of ferrous metals employed in conjunction with a corrosive hydrocarbon 75 employed in conjunction with corrosive hydrocarbon

3,017,356 23. 24 fluids characterized by treating said metals with a com- References Cited in the file of this patent pound of the formula: UNITED STATES PATENTS g 2N 2,468,163 Blair et al. ------Apr. 26, 1949 N 3-CHCH-0-0-{X-6 X 5 2,468,180 De Groote et al. ------Apr. 26, 1949 S/ NN. 2,773,879 Sterlin ------Dec. 11, 1956 & Ha k 2,836,557 Hughes ------May 27, 1958 where R is a tallow-derived hydrocarbon.