2,987,521 United States Patent Office Patented June 6, 1961

2,987,521 (3) POLYMERIC PARTIAL ESTERS OF HYDRO CARBONDMDAZOLINY LALKANOLS AND DICARBOXYLECACDS William B. Hughes, Webster Groves, and Verner L. Stromberg, Shrewsbury, Mo., assignors to Petroite Corporation, Wilmington, Del, a corporation of Delar in which Ware No Drawing. Filed Mar. 3, 1958, Ser. No. 718,489 R-- 3 Claims. (C. 260-309.6) This invention relate sto esters of hydroxyaliphatic 10 and FC-R-C-F are the residual radicals derived from cyclic amidine compounds and polycarboxylic acids, said the carboxylic acids: esters containing at least one unesterified carboxylic acid group (i.e., where at least one but not all of the carboxylic R-C-OH or R-coil), acid groups are esterified, hereafter referred to as "partial esters”). More particularly, this invention relates to a 15 where R comprises, for example, a saturated or unsatu process of preparing these partial esters which comprises rated aliphatic radical, a cycloaliphatic radical, an aryl reacting a hydroxyaliphatic cyclic amidine, for example, radical, an aralkyl radical, an alkaryl radical, an alkoxy a hydroxyaliphatic imidazoline, or tetrahydropyrimidine alkyl radical, an aryloxyalkyl radical, and the like; and with less than a stoichiometric amount of a polycarboxylic A is an alkylene group, for example, ethylene and propyl acid so that at least one of the carboxylic acid groups 20 ent radicals have a main chain of 2 or 3 carbon atoms, remains unesterified. This invention also relates to a such as -CH2-CH2-, -CH2CHCH process of using these partial esters as corrosive inhibitors CH GHs GHs in preventing the corrosion of metals, most particularly iron, steel and ferrous alloys. CH-OH- -CH-bH-OH,- - E-la Heretofore, a wide variety of cyclic amidine com 25 E8 pounds have been employed to inhibit the corrosion of and x is a whole number, 1 or greater, for example, 1-2, oil well equipment. Although we have expected that hy and R is the partial ester group derived from the reaction droxyaliphatic cyclic amidines would also be effective in of a hydroxy containing alkylene, polyoxyalkylene, etc. inhibiting oil field corrosion, we found that these com groups with less than a stoichiometric amount of the poly pounds had very poor corrosion inhibiting properties. 30 carboxylic acid, However, we have now unexpectedly discovered that certain derivatives of these hydroxyaliphatic cyclic ami O dines, particularly the partial esters thereof, are very ef (i.e., the R' contains at least one--OH group) fective corrosion inhibitors, in many cases from 10 to 15 or more times as effective as the corresponding hydroxy- ..35 More specifically, the corrosion inhibiting aspect of this aliphatic cyclic amidine. The corrosion inhibitors dis invention relates to a method of inhibiting corrosion of closed herein are particularly useful in preventing the ferrous metals by hydrocarbon fluids containing water corrosion of pil well equipment, for example, in producing and corrosive materials such as H2S, CO2, inorganic wells, pipe lines, refineries, tank storage, etc., which are acids, organic acids, etc., combinations of these materials in contact with corrosive oil-containing medium, for ex 40 with each other, combinations of each of said corrosive ample, in oil wells producing corrosive oil or oil-brine materials with oxygen, and combinations of said mate mixtures in refineries, and the like. These compositions rials with each other and oxygen, which comprises treat possess properties which impart to metals resistance to ing such ferrous metals such as by adding to said fluids attack by a wide variety of corrosive agents, among which at least 5 parts per million of the above partial esters, said may be mentioned brines, organic and inorganic acids, 45 compounds being sufficiently soluble in the hydrocarbon CO2, H2O, Oa, etc., and combinations thereof. fluid to inhibit corrosion. More specifically, the above described compounds may be described by the formulae: THE HYDROXY ALIPHATICYCLIC AMIDINE () A. The expression “cyclic amidines' is employed in its 50 usual sense to indicate ring compounds in which there are NC \ly present either 5 or 6 members, and having 2 nitrogen n c^ J atoms separated by a single carbon atom supplemented k . by either two additional carbon atoms or three additional carbon atoms completing the ring. All the carbon atoms (2) - A 55 may be substituted. In the present instance the nitrogen NY Y, atom of the ring involving two monovalent linkages (the Se/ y 1-position) is substituted with a hydroxy aliphatic group, i.e., -(RO),H group when R is alkylene and n is a 60 whole number, for example, 1-5 or higher. N1 Ys These cyclic amidines are further characterized as ...... N/ being Substituted imidazolines and tetrahydropyrimidines in which the two-position carbon of the ring is generally (the dotted lines indicate reactivity with the exact nature of the product bonded to a hydrocarbon radical or comparable radical being undetermined, probably polymeric) 65 derived from an acid, such as a low molal fatty acid, a 2,987,521. 3 high molal fatty acid, or comparable acids, polycarboxy oic acids, for example, petrosilenic acid, oleic acid, elidic acids, and the like. acid, the nonadecenoic acids, for example, the eicosenoic For details of the preparation of imidazolines substi acids, the docosenoic acids, for example, erucic acid, tuted in the 2-position from amines, see the following brassidic acid, cetoleic acid, the tetracosenic acids, and the U.S. patents, U.S. No. 1,999,989, dated April 30, 1935, like. Max Bockmuhl et al.; U.S. No. 2,155,877, dated April Examples of dienoic acids comprise the pentadienoic 25, 1939, Edmund Waldmann et al.; and U.S. No. acids, the hexadienoic acids, for example, sorbic acid, 2,155,878, dated April 25, 1939, Edmund Waldmann et the octadienoic acids, for example, linoleic, and the like. al. Also see Chem. Rev. 32, 47 (43), and Chem. Rev. Examples of the trienoic acids comprise the octade 54,593 (54). 0 catrienoic acids, for example, linolenic acid, eleostearic Equally suitable for use in preparing compounds use acid, pseudo-eleostearic acid, and the like. . . ful in our invention and for the preparation of tetra Carboxylic acids containing functional groups such as hydropyrimidines substituted in the 2-position are the hydroxy groups can be employed. ... Hydroxy acids, par corresponding polyamines containing at least one primary ticularly the alpha hydroxy acids, comprise glycolic acid, amino group and one secondary amino group, or, another 5 lactic acid, the hydroxyvaleric acids, the hydroxy caproic primary amino group separated from the first primary acids, the hydroxyheptanoic acids, the hydroxy caprylic amino group by three carbon atoms instead of being acids, the hydroxynonanoic acids, the hydroxycapric acids, separated by only 2 carbons as with imidazolines. This the hydroxydecanoic acids, the hydroxy lauric acids, the reaction as in the case of the imidazoline is generally hydroxy tridecanoic acids, the hydroxymyristic acids, the carried out by heating the reactants to a temperature at 20 hydroxypentadecanoic acids, the hydroxypalmitic acids, which 2 moles of water are evolved and ring closure is the hydroxyhexadecanoic acids, the hydroxyheptadecan effected. For details of the preparation of tetrahydro oic acids, the hydroxy stearic acids, the hydroxyoctade pyrimidines, see German Patent No. 700,371, dated De cenoic acids, for example, ricinoleic acid, ricinelaidic cember 18, 1940, to Edmund Waldmann and August acid, hydroxyoctadecynoic acids, for example, ricin Chwala; German Patent No. 701,322, dated January 14, 25 stearolic acid, the hydroxyeicosanoic acids, for example, 1941, to Karl Kiescher, Ernst Urech and Willi Klarer, and hydroxyarachidic acid, the hydroxydocosanoic acids, for U.S. Patent No. 2,194,419, dated March 19, 1940, to example, hydroxybehenic acid, and the like. . - , Examples of acetylated hydroxy acids comprise ricin AugustSubstituted Chwala. imidazolines and tetrahydropyrimidines- - are 30 oley lactic acid, acetyl ricinoleic acid, chloroacetyl ricin obtained from a variety of acids beginning with the one oleic acid, and the like. - carbon acid (formic) through and including higher fatty Examples of the cyclic aliphatic carboxylic acids com acids or the equivalent having as many as 30 carbon prise those found in petroleum called naphthenic acids, atoms for example from 8-22 carbons. Modified fatty hydnocarbic and chaumoogric acids, cyclopentane car acids also can be employed as, for example, phenyl 35 boxylic acids, cyclohexanecarboxylic acid, campholic acid, stearic acid or the like. Cyclic acids may be employed, fencholic acids, and the like. including naphthenic acids. A variety of other acids Examples of aromatic monocarboxylic acids comprise including benzoic acid, substituted benzoic acid, ali benzoic acid, substituted benzoic acids, for example, the cyclic acid, and the like, have been employed to furnish toluic acids, the xyleneoic acids, alkoxy benzoic acid, the residue - - - - 40 phenyl benzoic acid, naphthalene carboxylic acid, and RC the like. . . - Mixed higher fatty acids derived from animal or vege from the acid RCOOH in which the C of the residue table sources, for example, lard, cocoanut oil, rapeseed oil, sesame oil, palm kernel oil, palm oil, olive oil, corn oi, cottonseed oil, sardine oil, tallow, soyabean oil, peanut R oil, castor oil, seal oils, whale oil, shark oil, and other is part of the ring. The fatty acids employed, for ex fish oils, teaseed oil, partially or completely hydrogenated ample, may be saturated or unsaturated. They may be animal and vegetable oils are advantageously employed. hydroxylated or nonhydroxylated. Branched long chain 50 Fatty and similar acids include those derived from various fatty acids may be employed. See J. Am. Chem. Soc. waxes, such as beeswax, spermaceti, montan wax, Japan 74, 2523 (152). This applies also to the lower molec wax, coccerin and carnauba wax. Such acids include ular weight acids as well. - ...... carnaubic acid, cerotic acid, lacceric acid, montanic acid, Among sources of such acids may be mentioned straight psyllastearic acid, etc. One may also employ higher mo chain and branched chain, saturated and unsaturated, 55 lecular weight carboxylic acids derived by oxidation and aliphatic, cycloaliphatic, aromatic, hydroaromatic, aralkyl other methods, such as from paraffin wax, petroleum and similar hydrocarbons; resinic and hydroaromatic acids, acids,Examples etc. .of . saturated. . . aliphatic. . . . monocarboxylic------acids such as hexahydrobenzoic acid, hydrogenated naphthoic, comprise: - acetic, propionic, butyric, valeric, caproic, hydrogenated carboxy diphenyl, naphthenic, and abietic heptanoic, caprylic, nonanoic, capric, undecanoic, lauric, 60 acid; aralkyl and aromatic acids, such as Twitchell fatty tridecanoic, rhyristic, pentadecanoic, palmitic, heptade acids, naphthoic acid, carboxydiphenyl pyridine carboxylic canoic, stearic, nonadecanoic, -eicosanoic, heneicosanoic, acid. blown oils, blown oil fatty acids and the like. docosanoic, tricosanoic, tetracosanoic, pentacosanoic, Other suitable acids include phenylstearic acid, ben cerotic, heptacosanoic, montanic, nonacosanoic, melissic Zoylnonylic acid, cetyloxybutyric acid, cetyloxyacetic and the like. ------...... ” ------65 acid, chlorstearic acid, etc. - Examples of ethylenic unsaturated aliphatic acids com Examples of the polycarboxylic acids comprise those prise: acrylic, methacrylic, crotonic, anglic, teglic, the of the aliphatic series, for example, oxalic, malonic, suc pentenoic acids, the hexenoic acids, for example, hydro cinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, Sorbic acid, the heptenoic acids, the octenoic acids, the nonanedicarboxylic acid, decanedicarboxylic acids, undec nonenoic acids, the decenoic acids, for example, obtusilic 70 acid, the undecenoic acids, the dodencenoic acids, for anedicarboxylic acids, and the like. example, lauroleic, linderic, etc., the tridecenoic acids, the Examples of unsaturated aliphatic polycarboxylic acids tetradecenoic acids, for example, myristoleic acid, the comprise fumaric, maleic, mesoconic, citraconic, glu pentadecenoic acids, the hexadecenoic acids, for example, tonic, itaconic, muconic, aconitic acids, and the like." palmitoleic acid, the heptadecenoic acids, the octodecen. 75 Examples of aromatic polycarboxylic acids comprise

2,987,521 - 5 6 phthalic, isophthalic acids, terephthalic acids, substituted radical; and D is a hydroxy-aliphatic radical, for ex derivatives thereof (e.g. alkyl, chloro, alkoxy, etc. deriva tives), biphenyldicarboxylic acid, diphenylether dicar ample, -ROH or -R-(OR), OH, wherein k is a boxylic acids, diphenylsulfone dicarboxylic acids and the whole number, for example, 1-10 or more but preferably like. 1-5 and CH is, for example, a -divalent radical of the Higher aromatic polycarboxylic acids containing more formula: -CH-CH, -CHCH-CH2-, than two carboxylic groups comprise hemimelitic, tri mellitic, trimesic, mellophanic, prehnitic, pyromellitic -CH-H-CH, acids, mellitic acid, and the like. etc...... Other polycarboxylic acids comprise the dimeric, tri 0. In general, the hydroxyalkyl cyclic amidines are pre meric and poly acids, for example, the Emery Industries pared by reacting a polyamine containing a terminal polymeric acids such as those described in U.S. Patent alkanol group with a carboxylic acid at temperatures of 2,263,612, and the like. Other polycarboxylic acids com from 150-175 C. employing an azeotroping agent such prise those containing ether groups, for example, digly as xylene to remove water. The reaction time of 3-4 collic acid. Mixtures of the above acids can be advan tageously employed. 5 hours is employed. Completion of reaction is judged In addition, acid precursors such as esters, acid chlo by the separation of 2 moles of HO for each carboxylic rides, glycerides, etc. can be employed in place of the acid group. The products in general are dark viscous free acid. oil... Since the preparation of cyclic amidines is so well Where the acid contains functional groups such as 20 known (see above, cited patents) it is not believed that hydroxy groups, this should be taken into consideration any examples are necessary to illustrate such a well known in subsequent acylation in calculating the stoichiometry procedure. However, for purposes of illustration the of acylating the hydroxyaliphatic cyclic amidine. .. following examples are included. Hydroxy substituted imidazolines and tetrahydro pyrimidines are obtained in the manner described above 25 Example 10a , , , , from a wide variety of polyamines containing hydroxy A solution of 1 mole of hydroxyethyl ethylene diamine, groups. Thus, where one starts with a polyamine, for example, a diamine of the following formula Hochsch-NCHCH-NH. 30 and 1 mole of oleic acid in 300 grams of xylene are charged to a flask and brought to reflux, the mixture be where R has 2 or 3 carbon main chains one obtains the ing heated under a Dean-Stark water trap condenser in hydroxyalkylene compounds useful in this invention. In order to distill off the water-xylene azeotrope mixture, addition, one can start with ethylene diamine or with 1,2- 35 separate the water and to continuously return xylene to propylene diamine, 1,3-propylenediamine or other poly the reaction mixture. Reflux is continued at a tempera amines and then react the cyclic amidine so obtained ture of 160-170° C. for about 3% hours until about 2 with alkylene oxides so as to produce a terminal hy moles of water are removed. The product is droxyl group since the nitrogen bonded hydrogen on the gh-pH, 1-position on the group reacts with alkylene oxides. In 40 N N-CHCH-OH addition the hydroxyalkylene groups can be oxyalkylated. N/ Alkylene oxides comprise those of the general formula g ?iths R-CH-CH, 45 Example 9b ------r where R is H or an alkyl group. Among the alkylene The above example is repeated except that hydroxy oxides that may be employed are ethylene, propylene, ethyl propylene diamine 1-3, ...... butylene, octylene, etc. oxides, etc. Other oxyalkylation H agents such as glycide, epichlorohydrin, etc., can be em ployed. 50 Ho CHCH-CHCHCH.NE, Thus, compounds, within the scope of this invention is employed in place of hydroxyethylethylene diamine which react with polycarboxylic acids comprise com and stearic acid is employed in place of oleic acid. The pounds of the formulae: product is N 55 2 e R-of cB), CH H. N nc^N-CHCHOH 60 1785 s N N Example 4c (ce N-- on Example 1.0a is repeated except that l 65 where Hochschi CH, CHNH (2 moles) and a polycarboxylic acid, sebacic acid (1 Ré mole), are employed. Instead of two moles of water is the residue derived from the carboxylic acid, where R being removed, as in the prior example, 4 moles of water is a hydrocarbon radical having, for example, up to 70 are removed. The product is about 30 carbon atoms such as 1-30 carbon atoms, and hydrocarbons in which the carbon atom chain is inter pH-H, H-pH, rupted by oxygen, etc., n is 2 or 3, and B is a hydrogen HO-CECHN N r N. N-COOH or a hydrocarbon radical, for example, a lower alkyl 75 Yo1-(CH). So, i. 2,987,521 7 8 . . . " Example 20d - CH-OH, - - - Example 4c is repeated with ...... -(CHOHO)a. .

HOCHCHNCHCHCH-NH,- ' ' ' - ...... Cia . (2 moles) and the polycarboxylic acid is terephthalic . . . . acid (1 mole). As in the prior example, 4 moles of The above examples are typical methods of preparation. water are removed. The product is The following hydroxycyclic amidines are prepared by -. "...... 'Atri...... R.. . these methods. TABLE...... pH, (H, - gh, CH ; : HOCHCH-N N N i-CECH-OH Ye1C. (). So?C - N -R In general, to form the polyoxyalkylated hydroxy cyclic R amidines, the hydroxyalkylcyclic amidine is first prepared in the mannershown above and then reacted with alkylene Ex. RCOOHSource. of. . . . - - - R oxides by the conventional manner of oxyalkylation to the 20 No. RO ...... desired degree of oxyalkylation using a jacketed stainless steel autoclave in the manner described in U.S. Patent Lauric--- . CHCHOH 2,792,369. The following examples are illustrative:vira Ab IsowalericHexanoic CH2CH2OECHCH-OH 1. A compound containing at least one free carboxylic SES. 3E3E3 . . . acid group formed by reacting a compound having the Estatio. SH33 formula - - Benzoic------CHCH-OH . . - CHCBOE s CHCH-OH - N N CECEO...... 1 S 2 OECHOCCEO (CB)-N1 C-R-ON/ CB) - E. E. Aori - f Aloh HCHOCHCHO B - . . . - . Example. . ' ' 11a Cerotic.------8335,585.CEOHOCHCH-OH2 . . . One mole of 16a-p-tert-Butylbenzoic. CHCEOCECHOE ' 35 17a----Benzoic------CECHOCHOHOH 18a.----. Toluic----- CECHOCHOHOE, 19a---- Naphthenic CHCHOOHCHOE 20d.---- OHCHOOHCHOB, N-CHCHOE CHCHOOHCHOCH2CHOH. N/ OH,CHOCHCHOCHCH-OH C CHCHOCH2CHOCH2CH2OHCHCHQCECHOCH29H29E C17Has CHCHOCHOHOCECHOH.CHCHOCHCOCH2CHOE (50% solutionIn inO xylene) is reacted with 1 mole of ethyl w CHCHOOHOHOCH2CH2OH.SESE36E5353E3 ene oxide at a temperature of 125-130 C. and a pressure 29a---- 3-methoxybenzoic CHCHOCHCOCEICO of 10-15 psi The time regulator is set to add ethylene 30---- Naphthenic------CHCHOC.H.CHOOH,CH,OH oxide over 2 hour followed by additional stirring for 45 another. 2 hour to insure complete reaction. Ethylene oxide is readily taken up by the reactants. The product . . . . . TABLE II is - -

(H-H, so ?h N N-CHCHO CHCHOE N N-R . . . N/ . . . . . N / &H Example 12a 55

The above example is repeated using a propylene oxide E. No. Rooo source of Ro R and . . . - lb.------Formio.------CHCH, OH Acetic------CECHO

CH 3b--- Butyric- CECHO N s-?- d CBI-O .60- :6b. YiTrimethylSovaleric---- Ac CCHOHShoa2. C. : :". 7b. Peargonic- CHCHOI Lauric------CHCIO CCO C17His . . . . . ; ...... 9b----- Stearig.------CCHOH - ...... 9: filiatorylie.8538thor under similarO conditions.8. O The product iso 65 - II- - - Cerotic------ucOSane-carboxyllic SE36." 3:- - Eistentia.eny 88.1C - 3:33

H. -H, H. - (H...... ------:3:16- -methylbenzoNation; gEgg HaCH10

... . N,N-CHCH,0CHCH-OH. . C...... 17b.18b. CreSotiraic------CHCHOHCCHO

...... y . . . . . - - . . - 703: 8.33 CH2 ...... 21b.--22b---- Undecylienic. CICIOI.CHCO

Example 28a 23b-. Linoleic- CHCHO - o - 24b- Butyric- gH9H29H.

Example: 11a is repeated except that 2 moles of ethyl- CHCHOH

ene oxide are employed. The product is is

2,987,521. O TABLE II - Examples of unsaturated aliphatic polycarboxylic acids comprise fumaric, maleic, mesocenic, citraconic, glutonic, itaconic, muconic, aconitic acids, and the like. . . 2 n Examples of aromatic polycarboxylic acids comprise R-N C-R-CN-R :5 phthalic, isophthalic acids, terephthalic acids, substituted derivatives thereof (e.g. alkyl, chloro, alkoxy, etc. deriva Ex. HOOC-R-COOE R tives), biphenyldicarboxylic acid, diphenylether dicar No. Source of -CRC boxylic acids, diphenylsulfone dicarboxylic acids and the

like. . Malonic - CH2CH2OH Adipic-. CECIOH O Higher aromatic polycarboxylic acids containing more Suberie- CH2CH2OH than two carboxylic groups comprise hemimellitic, tri Sebacic- CH3CEOH mellitic, trimesic, mellophanic, prehnitic, pyromellitic - Nonodecaneboxylic. dicar- CH2CH2OH --- Piglycolic------CECH2OH. acids, mellitic, acid, and the like. . ------Payne Bis(gly- GH2CH2OEI Other polycarboxylic acids comprise the dimeric, tri -- Methylenedibenzoic.--CH2CH2OH2010). 5 meric and other poly acids, for example, the Emery In Stearyl Malonic------CHCHOH dustries polyacids such as those disclosed in U.S. Patent 10c---- Phthalic------CHCH2OH. lic- Succinic CH2CH2OCH2CH2OH 2,763,612, and the like. Other polycarboxylic acids com 2c. Glutaric CHCHOCH2CH2OH. prise those containing ether groups, for example, diglycol 3c- Pimelic CICIOCH2CH2O 4C- Azelaie- CECHO CB2CH2OH. lic acid. Mixtures of the above acids can be advanta 15c --- Eicosahedicarboxylic. CH2CH2OCH2CH2OE, 20 geously employed...... 17c----.6c---- Isophthalic-Dillinoleic.------a CHCEOCH2CH2O CHCH2OHCH2CH2OH. In addition, acid precursors such as esters, acid chlo 18c.---- Diglycolic--- CH2CH2O CH2CH2OH. rides, glycerides, etc. can be employed in place of the 19c.---- Patry Malonic------CH2C2O CH2CH2OH free acid. 20c---- Methylene dibenzoic. CHCHOCH2CH2OH - - 21c.. Malonic..... ------CH2CH2OC2H2CH2O CE2CH29E 22c-... Succinic CH2CH29929H29CHCH2CH 25 THE PARTIAL ESTER PRODUCTS 23c---- Suberic- CECB, OCH2CHOCH2CH2OH 24c ---- Pimelic------. CHCHOCH2CHOCH2CH2OH The products of this invention are partial esters of 25c---- NgianOxylic. di CHCHOCH2CH2O CECHOH cyclic amidines. They may be expressed by the following 26c---- Diglycolic------CHCIO CH2CHOCH2CH2O general formula: 27c---. Methylene CECHO CECHO CHCHOH 28c. --- Steary malonic- CHCH2O C2H2CHO CBCEO . O 29c.. Stearyl succi CECHOCH2C2OCH2CH2OH 30 is . . . . . ( 4 - 30c --- Terephthalic. CECHO CH2CH2O CH2CO -C--OHA wherein. A comprises a molecule containing at least one TABLE EW cyclic amidine group having at least one ester side-chain 35 and c is a whole number preferably 1. The O R-N N N N-R N2 N/ C-R- of the formula indicates that the product is a partial ester Ex...No. HOOC-R-COOSource . R 40 having at least one free carboxylic acid group. of-CRC- - Thus, the products of this invention may be illustrated with dicarboxylic acids as follows: . . ; :

------CHCHOHCHCH2OH. CHCHOH CH2CHOH. . . . . CCH) CECHOH. 45 CHCHOH CH2CH2OCECH2OH.

CICH2OH. CHCHOH where X includes a Eicosane dicarboxylic- 9H29H29E. Diglycolic------CHCEIOE Ethylene bisglycolic------8E3 CHCH-OH Meylene dicarboxylic (CH3). CHCH2OH. 50 acC. -R'O-C- a (RO)n-Cis Dillinoleic----- CECHOH Stearylmaloni CECH29E etc. group and Z is the Laurylsuccinic CECHOE radical derived from the poly Isotetradecyls CHCH2OH. carboxylic acid. Phthalic------CHCHOCICHOH In the case where bicyclic amidine compounds are used sophthalic- CECH2OH. 55 as hydroxy precursors, the structure might possibly be as - CHCHORCHCHOE follows: CECHO N - THE POLYCARBOXYLIC ACIDs 60 NON-X,C V Q The polycarboxylic acid employed to react with the k 'z-oh hydroxycyclicamidine can be varied widely. In general, A. they can be expressed as - 4's f O NY-x R-con). 65 YAY where R comprises a saturated or unsaturated aliphatic wherein X and Z have the meanings of the preceding for radical, a cycloaliphatic radical, an aromatic radical, and mula groups. Since the hydroxy precursor is bifunctional the like, and x is a whole number equal to 2 or more, (i.e., has two hydroxy groups) and the polycarboxylic acid sfor example, 2-4, but preferably 2. 70 is also polyfunctional, polyesters probably form. Since Examples of the polycarboxylic acids comprise those the structure is uncertain, it is indicated by dotted lines. of the aliphatic series, for example, oxalic, malonic, suc These polyesters are useful as corrosion inhibitors pro icinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, vided they are partial esters (i.e. have at least one free nonanedicarboxylie -acid, decanedicarboxylic acids, run carboxylic acid group) and are sufficiently soluble in the -decanedicarboxylic acids, and the like. 5 hydrocarbon to be effective, 2,987,521. 11. 12 The following examples are illustrative of the prepara and 1 mole of diglycolic acid are employed. The product tion of partial esters. Two moles of carboxylic acid S radical are employed for each mole of hydroxy group. CH-CH O O Example, 10aa One mole of the product of Example 10a and 1 mole of sebasic acid are dissolved in 300 g. of xylene and the C1Ess reaction mixture, heated to reflux, is azeotroped, using a The above examples are typical methods of preparation. Dean-Stark trap in the manner of Example 10a, until one 0. The following partial esters are prepared by these meth mole of water is removed. The temperature is main ods. Each partial ester will have the basic number shown ined at 150-175 C. and the time is 5 hours. The prod in the prior tables, for example, 1a, 10a, etc., indicative uct is of the hydroxy cyclic amidine employed. In addition, it H.-H. will bear the letter A which indicates that it has been N. -CHCH.ob-(CH)-oh 5 acylated to a partial ester. In each example 2 moles of N/ carboxylic acid radicals are employed for each mole of g hydroxy groups. - - - - - CEas TABLE W.-PARTIAL ESTERS Example 10aC 2aB Adipic 9bB Sebacic The process of the prior example is repeated except that 4a.A. Sebacic 9bC Terephthalic terephthalic acid is employed in place of sebacic acid. 4aB Terephthalic 9bD Succinic 'The product is 10ab Adipic 21bA Sebacic 10ab Sebacic 21bB Terephthalic H-H - 10aC Terephthalic 4cA Dimeric (dilinolei 25 10a) Trimeric (trilinoleic acid) NN/ i-chohol-(X-son acid) 4cB Terephthalic His 10aB. Succinic 6CA Glutaric 13a.A. Sebacic 6cB Pimelic Example 10ad 13aB Adipic 6cC Adipic The above example is repeated employing 1.5 moles of 30 15aA Suberic 14cA Adipic 15aB Dimeric acid (dilino- 14cB Sebacic (H-H, leic) 23CA Sebacic N N-OHCO 24a A Adipic 23cB sophthalic S/ 24aB Isophthalic 23cC Adipic &ntia 35 28aA Diglycolic 8dA Adipic and 1 mole of trimeric acid (trilinoleic acid) to yield a 8bA Adipic 8dB Sebacic dark viscous product of undetermined structure. 9bA Adipic Example 9b.A. USE AS CORROSION INHIBITOR 40 More specifically, this phase of the invention relates to ... The process of the above example is repeated except the inhibition of corrosion in the petroleum industry with that 1 mole of specific reference to producing wells, pipe lines, refineries, tank storage, etc. ------The use of a corrosion inhibiting agent in the oil-in 45 dustry and other industries, and particularly for the pro tection of ferrous metals, is well known. For example, C see U.S. Patents Nos. 2,736,658, dated February 28, 1954, Chas to Pfohl et al., and 2,756,211, dated July 24, 1956, to is reacted with 1 mole of adipic acid. The product is Jones, and 2,727,003, dated December 13, 1955, to 50 Hughes. - - - - . More specifically then, and particularly from the stand off,ce. CH O O point of oil production, this aspect of the invention relates ! -CHCH-0--(CH)-oh to inhibiting corrosion caused by hydrogen sulfide, car N bon dioxide, inorganic and organic acids, combinations nc^ 55 of each with oxygen, and with each other and oxygen. th. More particularly, it relates to treating wells to mitigate Example 4cA metal corrosion and associated difficulties. - - - - - It should also be pointed out that the corrosiveness of The process of the above example is repeated except oil well brines will vary from well to well, and the pro that one mole of 60 portion of corrosion inhibiting agent added to the well QH-CH, CH-CH, fluids should also be varied from well to well. Thus, in BIO CHCH- l i-CHCH-OH some wells it is possible to effectively control corrosion 2 by the addition of as little as 5 p.p.m. of our new com of-(CHSc? positions to the well fluids, whereas in other wells, it is and 2 moles of dimeric acid (dilinoleic acid) are em necesary to add 200 p.p.m. or more. ployed. The structure of this product is uncertain except 65 In using our improved compositions for protecting oil that it is polymeric product containing free carboxylic well tubing, casing and other equipment which comes in acid groups. contact with the corrosive oil-brine production, we find Example 28aA that excellent results may be obtained by injecting an appropriate quantity of a selected composition into a The above process is repeated except that 1 mole of O producing well so that it mingles with the oil-brine mix GH-H, ture and come into contact with the casing, tubing, pumps N N-(CHCHO)3H and other producing equipment. We, for example, can Sc^ introduce the inhibiting composition into the top of the &nha r 5 casing, thus causing it to flow down into the well and

2,987,521 13 thence back through the tubing, etc. In general, we have much upon the exact reagent being used and its solubility found that this procedure suffices to inhibit corrosion throughout the entire system of production, and collec characteristics. It is also generally desirable to employ a solvent which will yield a solution of low freezing point, tion, even including field tankage. so as to ob the necessity of heating the solution and In case serious emulsion or gel problems are en injection equipment during winter use...... countered, demulsifiers are advantageously added. This For treating Wells with packed-off tubing, the use of is important not only to avoid the troublesome emulsions solid "sticks' or plugs of inhibitor is especially convenient. and gels themselves, but also to improve corrosion in These are prepared by blending the inhibitor with a min hibition. The explanation of less effective corrosion in eral wax, asphalt or resin in a proportion sufficient to hibition in the presence of emulsions apparently is that 10 give a moderately hard and high-melting solid which can the inhibitor is somewhat surface-active. That is, it is be handled and fed into the well conveniently. concentrated at interfacial surfaces. Since this surface The amount of corrosion preventive agent required in is great in an emulsion, most of the inhibitor will be con our process varies with the corrosiveness of the system, centrated in these interfaces and little will remain in the but where a continuous or semi-continuous treating proce body of the oil for deposition on the metal surfaces. In 15 dure is carried out as described above, the addition of re many wells, oil-in-water type emulsions often occur natu agent in the proportion of from 5 parts per million to rally. In such wells the inhibitors herein described tend 1000 parts per million or more, parts of corrosive fluid ing to form water-in-oil type emulsions, often decrease the will generally provide protection. emulsion problems naturally present. Thus, in addition These corrosion inhibitors can be used in combination to being effective corrosion inhibitors, the herein described 20 with other well-known corrosion inhibitors, for example, products tend to eliminate emulsion problems which some the cyclic amidine structures, the amido cyclic amidine times appear when some of the present day inhibitors are structures, and the amino cyclic amidines structures, as used in oil wells or refinery processing. disclosed in the Blair and Gross Reissue Patent No. The method of carrying out our process is relatively 23,227. When the herein described products are mixed simple in principle. The corrosion preventive reagent is 25 with corrosion inhibitors of the conventional type in the dissolved in the liquid corrosive medium in small amounts ratio of one-to-three, one-to-one, three-to-one, or the like, and is thus kept in contact with the metal surface to be in numerous instances the effectiveness of the corrosion protected. Alternatively, the corrosion inhibitor may be inhibitor, thus obtained is often significantly greater than applied first to the metal surface, either as is, or as a the use of either one alone...... solution in some carrier liquid or paste. Continuous 30 Since these products are basic they can be combined application, as in the corrosive solution, is the preferred with various acids to produce salts in which oil solubility method, however. is increased or decreased. Likewise, water solubility is The present process finds particular utility in the pro increased or decreased. For instance, the products are tection of metal equipment of oil and gas wells, especially mixed with one or more moles of an acid, such as higher those containing or producing an acidic constituent such 35 fatty acids, dimerized fatty acids, naphthenic acids, acids as H2S, CO2, inorganic and organic acids, O and the obtained by the oxidation of hydrocarbons, as well as like. For the protection of such wells, the reagent, either Sulfonic acids such as dodecylbenzene sulfonic acid, pe undiluted or dissolved in a suitable solvent, is fed down troleum mahogany acids, petroleum green acids, etc. the annulus of the well between the casing and producing What has been said in regard to the acids which in tubing where it becomes cominingled with the fluid in 40 crease oil solubility and decrease water solubility applies the well and is pumped or flowed from the well with these with equal force and effect to acids of the type, such as fluids, thus contacting the inner wall of the casing, the acetic acid, hydroxyacetic acids, gluconic acid, etc., all of ofter and inner wall of tubing, and the inner surface of all which obviously introduce hydrophile character when they well-head fittings, connections and flow lines handling the form salts or complexes, if complexes are formed. For corrosive fluid. 45 example, any of the acids described above in preparing Where the inhibitor composition is a liquid, it is con the cyclic amidines are useful in preparing these salts. ventionally fed into the well annulus by means of a motor As pointed out previously, the addition of corrosion in driven chemical injector pump, or it may be dumped hibitors, particularly in the form of a solution by means of periodically (e.g., once every day or two) into the annulus a metering pump or the like, is common practice. The by means of a so-called "boll weevil” device or similar ar 50 particular corrosion inhibitors herein described are ap rangement. Where the inhibitor is a solid, it is dropped plied in the same manner as other corrosion inhibitors in into the well as a solid lump or stick, blown in as a tended for use for the same purpose. For sake of brevity, powder with gas, or it may be washed in with a small as to the use of the corrosion inhibitor and its solution in stream of the well fluids or other liquid. Where there a suitable solvent such as mineral oil, methyl ethyl ketone, is gas pressure on the casing, it is necessary, of course, to 55 Xylene, kerosene, high boiling aromatic solvent, or even employ any of these treating methods through a pressure Water. equalizing chamber equipped to allow introduction of reagent into the chamber, equalization of pressure be STIRRING TESTs tween chamber and casing, and travel of reagent from These tests are run on synthetic fluids. The procedure chamber to well casing. 60 involves the comparison of the amount of iron in solution Occasionally, oil and gas wells are completed in such (after a predetermined interval of time of contact of a a manner that there is no opening between the annulus standardized iron Surface with a two-phase corrosive and the bottom of the tubing or pump. This results, for medium with similar determinations in systems containing example, when the tubing is surrounded at some point by inhibitors. a packing held by the casing or earth formation below 65 Six hundred ml. beakers equipped with stirrers and the casing. In such wells the reagent may be introduced heaters are changed with 400 ml. of 10% sodium chlo into the tubing through a pressure equalizing vessel, after ride-containing 500 p.p.m. acetic acid and 100 ml. of min stopping the flow of fluids. After being so treated, the eral spirits. The liquids are brought to temperature and a well should be left closed in for a period of time sufficient 1 x 1 inch sand blasted coupon is suspended by means of O a glass hook approximately midway into the liquid phase to permit the reagent to drop to the bottom of the wel1. of the beaker. The stirrer is adjusted to agitate the liquids For injection into the well annulus, the corrosion inhibi as such a rate as to provide good mixing of the two layers. tor is usually employed as a solution in a suitable solvent, After 30 fininutes samples of the aqueous phase are Such as mineral oil, methylethyl ketone, xylene, kerosene, taken and the iron content of each sample is determined or even water. The selection of solvent will depend 5 by measuring the color formed by the addition of hydro 2,987,521 15 16 chloric acid and potassium thiocyanate in a photoelectric The unexpectedness of the invention is quite evident colorimeter. from the above data. The products of the present inven The protection afforded by an inhibitor is measured by tion are superior to both the unesterified imidazoline and comparison of the amount of light absorbed by inhibited to other commercial inhibitors containing the imidazoline and uninhibited samples run simultaneously. Percent structure. The commercial inhibitors with which the protection can be determined by the following formula: partial esters were compared were those chosen fo standards of excellent performance. A1-A2 X 100=percent protection A1 OTHER USES where A1 is the present light absorbed by an uninhibited 0 sample and A2 is the same value for an inhibited sample. These products are effective not only as corrosion : Sults of a typical run are set forth in the following inhibitors but can be used for a number of other pur table: poses. For instance, they are useful as asphalt additives TABLE WI to increase the adhesiveness of the asphalt to the mineral 5 aggregates. In the form of water soluble salts, they are girl-pH, useful as bactericides in the secondary recovery of oil. N N-C-COH The hydroxycyclic amidine may be subjected to extensive n/ . oxyalkylation by means of ethylene oxide, propylene oxide, butylene oxide, or the like prior to acylation. 20 These are oxyalkylated and still have oil solubility as, for Stirring Test at Roon example, by the addition of propylene oxide or butylene Temperature. Inhi Inhibitor bition concentration oxide, or are oxyalkylated to produce water solubility as, of 10 p.p.m. based on for example, by means of ethylene oxide, glycide, etc. Ex, total fluids They are also oxyalkylated by combinations of propylene 25 oxide and ethylene oxide so that both water solubility R Acid Wgt. Loss, Percent and oil solubility remain. Thereupon they are reacted Mg. Protection with polycarboxylic acids. Such products are useful for

. . . . - Blank.------102.2 ------a variety of purposes and particularly for those where 100A.------CH33.---. Adipic.--- 0 99 nonionic surfactants or sequestered cationic surfactants :0dB--- C17H33----- Sebacic------0.6 99 30 C17H33----- Terephthalic---- 0.4 99 are indicated. C17H33----- Adipic-. 1.1 98 In addition, the compounds of this invention have the 2a.A.------Cs FI11----- Adipic 4.3 95 C17H33----- None 1 78.4 23 following applications: m Commercial inhibitor A 22.2 79 Agriculture.-Additive for kerosene, use in phenothi Commercial Inhibitor B2.-- 20.9 80 azine and pyrethrum sprays, as fungicides, herbicidal oils. 35 The unesterified amine. Anti-static treatment.-For hotel rugs, hospital floors, ; : Infra-red analysis indicates inidazoline structure. automobile upholstery, plastic and wax polishes, wool oils, lubricants for synthetic fibers. TABLE WI Building materials.-Water repellent treatment for Stirring test at 140°F.' 40 p.p.m. 40 plaster, concrete, cement, roofing materials, air entrain Inhibitor ment, floor sealers, linoleum. Ex. Percent Protection Cosmetics.--Formulation of anti-perspirants, deodor R Acid - ants, sun screens, hair preparations. De-emulsifying-In antibiotic extraction, breaking --- C17H33-...-- Sebacic------99 crude oil and water-gas for emulsions. C17H33- Terephthalic---- 99 45 - C17H35.---- Adiplc.--- 97 Detergents.-Metal cleaning emulsions, lens cleaners, CH33.----- None ---- 19 floor oils, dry cleaning detergents, radiator flushes, cess Commercial Inhibitor A2-...--- 8 pool acid, boiler scale solvents, germicidal corrosion It has been noted that some compounds have a definite actuation inhibited acid detergents for dairies, enamel equipment, energy so these tests are often run at room temperature as well as at toilet bowls. elevated temperature. 50 Unesterified annine. Leather.-Flat liquoring oils, pickling acid degreasing, - 2 Infra-red indicates inidazoline structure. dye fixative. Metals.-Rust preventive oils, cutting oils, water dis TANKERTESTs (CYCLE TESTs) placing compounds, pickling inhibitor, solvent degreasing. This test was described by Malcolmson et al. (Annual Paints-For improved adhesion of primers, preventing Meeting of the Society of Naval Architects and Marine 55 Engineers, New York, November 1952). It involves water spotting in lacquers, anti-skinning, pigment flushing, the measurement by weight loss of coupons which have grinding and dispersing, anti-feathering in inks. been subjected to the corrosive action of sea water and Petroleum-Use as a germicide in flood water treat a hydrocarbon for a week followed by contact for one ment, de-emulsifying fuel oil additives, anti-strip agent week with sea water and air, and the composition there 60 in asphalt emulsions and cutbacks. to the weight loss of coupons subjected to a similar test Textiles.-In rubberizing, textile oils, dyeing assistants, in which a small amount of inhibitor has been added to softening agents. the hydrocarbon phase. Miscellaneous-Bentonite-amine complexes, metal TABLE VIII-TANKER TEST (CYCLE TEST) Inhibitor. Wgt. Loss, Mg. Percent Protection . Ex. - R Acid p.p.m.10 p.p.m.20 p.p.m.30 p.p.m.10 p.p.m.20 p.p.m.30 10aC. - C17H33.---- Terephthalic---- 11.0 9.5 17 72. 76.0 76.0 13aB. CH35----- Adipic------11.8 12.8 8.2 56.2 68.0 54.5 Commercial Inhibitor C1 - 21.2 9.6 20,0 5 0.0 52.5 53.0 OH33, Free Alcohol, Wgt. Loss (100 p.p.m.) 200.6, Percen Protection (100 p.p.m.) 4.5 Infrared indicates imidazoline structure. - i.

2,987,621. 17 8 amine complexes, preparation of pentachlorphenates, where R is hydrocarbon having 1-36 carbon atoms, and quaternaries, plastisols, and rodent repellents. A is lower alkylene having at least two carbon atoms, Having thus described our invention what we claim as with at least one mole of a polycarboxylic acid having new and desire to obtain by Letters Patent is: the formula 1. A compound containing at least one free carboxylic acid group formed by reacting a compound having the formula N N where R is hydrocarbon having 1-36 carbon atoms. 3. A compound formed by reacting one mole of 0. c6.N.--- CB) 2-3 CH-CH CH-CH N/ N HO CHCH- N N N-CH2CH2OH oH loh n/ where R is hydrocarbon having 1-36 carbon atoms, B is 5 with two moles of dilinoleic acid. selected from the group consisting of hydrogen and lower alkyl, and A is lower alkylene having at least two carbon References Cited in the file of this patent atoms, with at least one mole of a polycarboxylic acid UNITED STATES PATENTS having the formula 2,211,011 Chwala ------Aug. 13, 1940 20 2,267,965 Wilson ------Sept. 30, 1941 2,324,491 De Groote et al. ------July 20, 1943 where R is hydrocarbon having 1-36 carbon atoms. 2,369,818 De Groote et al. ------Feb. 20, 1945 2. A compound containing free carboxylic acid group 2,468,163 Blair et al. ------Apr. 26, 1949 formed by reacting a compound having the formula 2,468,180 De Groote et al. ------Apr. 26, 1949 25 2,574,537 De Groote et al. ------Nov. 13, 1951 2,640,029 Blair et al. ------May 26, 1953 2,695,884 Smith ------Nov. 30, 1954 2,713,559 Smith ------July 19, 1955 2,713,582 Smith ------July 19, 1955 30 2,773,879 Sterlin ------Dec. 11, 1956 loh loh 2,845,439 Grant et al. ------July 29, 1958