Patent GB-809001-A (GB)
Title: Improvements in or relating to the prevention of corrosion
IPC: C10M133/02
Filed: 1955-02-04
Abstract: A corrosion inhibitor for hydrocarbons (e.g. gasoline, kerosene, burning oils and lubricating oils), comprises a salt or salt complex of (1) a polyamino compound containing solely C, H, O, and N and having at least 2 basic N atoms and at least 1 "hydrophobic group of at least 8 uninterrupted C atoms," which term includes hydrophobic groups wherein the C to C linkage is interrupted by O, (2) a polycarboxy acid having 2-4 carboxy groups and at least 1 hydrocarbon radical containing not less than 8 C atoms exclusive of carboxy groups, and (3) a monocarboxy acid having 8-32 C atoms, the formation of said salt involving at least 1 mol. each of the poly- and mono-carboxy acid for each mol. of the polyamino compound.  The polyamino compound may be an aliphatic polyamine, abietyl diamine (a commercial diamine obtained from rosin), an amido-amine, cyclic amidine, ester amine, oxazoline or pentoxazoline.  It is preferably surface-active as such or when hydrated or in salt form. Particularly useful salt complexes are obtained from a dibasic, triamine-derived, cyclic amidine, a monoethylenic fatty acid of 8-22 C atoms, and a dimeric or trimeric acid obtained by condensation of unsaturated or hydroxy aliphatic monocarboxylic acids of 16-18 C atoms such as linseed oil fatty acids.  Numerous examples of the salts are given (see Group IV (b)).  They are added in amounts of 5-50 p.p.m. and prevent corrosion and rusting both in presence and absence of oxygen.ALSO:A corrosion inhibitor comprises a salt or salt complex of a polyamino compound containing solely C, H, O, and N and having at least 2 basic N atoms and at least 1 hydrophobic group of at least 8 "uninterrupted C atoms," which includes hydrophobic groups wherein the C to C linkage is interrupted by O; a polycarboxy acid having 2-4 carboxy groups and at least 1 hydrocarbon radical containing not less than 8 C atoms exclusive of carboxy groups; and a monocarboxy acid having 8-32 C atoms; formation of said salt involving at least 1 mol. each of the poly- and mono-carboxy acid for each mol. of the polyamino compound.  The polyamino compound may be an aliphatic polyamine, abiethyl diamine (a commercial diamine obtained from rosin), an amido-amine, cyclic amidine, ester amine, oxazoline or pentoxazoline.  It is preferably surface active as such or when hydrated or in salt form.  Particularly useful salt complexes are obtained from a dibasic, triamine-derived, cyclic amidine, a mono-ethylenic, fatty acid of 8-22 C atoms, and a dimeric or trimeric acid obtained by condensation of unsaturated or hydroxy aliphatic monocarboxylic acids of 16-18 C atoms such as linseed oil fatty acids.  The polyamines used may be represented: <FORM:0809001/IV (b)/1> where X = 0 to 8, R is an hydrocarbon radical derived from a higher aliphatic, naphthenic, rosin or oxidized wax acid, R1 is an alkylene radical, and R11 is H, alkyl, cycloalkyl, aryl, aralkyl or the same as R.  They may be obtained by reacting high molar prim. or sec. amines with acrylonitrile and hydrogen or an alkylene imine. Diamines listed include "Duomeens" (Registered Trade Mark), a rosin diamine, and N-alkyl alkylene diamines.  The cyclic amidines are derived from polyamines and higher carboxylic acids, preferably mono- or di-carboxy which give amidines containing only 1 or 2 rings. Typical of many listed are 2-undecyl-imidazoline, 1-triethylenetriamino - 2 - hydroxyheptadecyleneylimidazoline, 1 - N - aminoethyl aminoethyl - 2 - dodecyl - 4 - methyl - tetrahydropyrimidine, and two ring amidines: <FORM:0809001/IV (b)/2> The amido-amines are similarly derived, typical examples being N,N1-di-(aminoethyl) sebacic diamide, and amides made by acylating of polyamines having a tert. amino group, e.g. <FORM:0809001/IV (b)/3> The ester-amines are made by esterifying with higher carboxylic acids, polyamines wherein all amino groups are substituted by alkyl and hydroxyalkyl groups, typical esters including: <FORM:0809001/IV (b)/4> and <FORM:0809001/IV (b)/5>  The oxazolines may be obtained from alkylolamines having at least 1 hydroxy and at least 1 primary amino group in the 1:2 or 1:3 positions and high molar carboxylic acids, a further basic N being introduced if necessary into the product which contains at least 1 oxazoline or pentoxazoline ring. This may be effected where a free OH group is present by reaction with alkylene imine or amino-alkylene oxide.  Typical of the examples given are 2-amino - 2 - methyl - 1,3 - propanediol+stearic acid gives: <FORM:0809001/IV (b)/6> the OH being replaced by treatment with ethylene imine or amino-propylene oxide; <FORM:0809001/IV (b)/7> where: <FORM:0809001/IV (b)/8> and R=C11H23.  With dimeric fatty acids, the products contain 2 oxazoline rings.  Imidazolines and tetrahydropyrimidines are other suitable polyamino compounds obtained by conventional methods from polyamines, e.g. N-dodecyl diethylenetriamine, and low or high molar acids.  An imidazoline obtained from a tetramine or pentamine may be converted with an acid to an amido derivative or oxyalkylated and then esterified. Piperidine, morpholine, and piperazine derivatives suitable as the polyamino compound are those of the formul : <FORM:0809001/IV (b)/9> where R1 is phenyl substituted by propyl, butyl or other alkyl radical and X is O or CH2, and <FORM:0809001/IV (b)/10> where X is R or R.CO (R being long chain aliphatic), R1 is H or short chain alkyl or acyl, and m and n are integers from 1-20.  Quinoline and dipyridine derivatives are also specified and non-cyclic amidines <FORM:0809001/IV (b)/11> where R1, R2 are H or alkyl and n is 7-13. Mixtures of polyamino compounds may be used.  Polycarboxylic acids specified include aryl ketonic tetracarboxy acids both mono- and dicyclic, the tetracarboxy acids formed by polymerizing an adduct of a dienophilic dibasic acid and a cyclic polyolefin and acidifying, aryl ketonic tricarboxy acids, substituted pimelic acids with 3 carboxy groups, tricarboxylic acids derived from the condensation of maleic anhydride and an unsaturated acid such as linolenic, soya bean, linseed or peanut acids, and dicarboxy acids such as sebacic, methylene disalicylic, maleic anhydride adducts with terpenes, dimerized fatty or rosin acids, particularly dilinoleic, condensation products of dimerized acid esters and alkylated naphthalenes, alkenyl succinic acids, substituted malonic acids, numerous references being given to the U.S. Patent literature.  Monocarboxylic acids include aliphatic, naphthenic, rosin, and wax oxidation acids, particularly mono-ethylenic fatty acids from fats and oils or synthetic sources, preferably oleic and undecylenic.  Production of the salts or complexes is effected by warming together at a sufficient temperature to give a homogenous mixture, a solvent such as an hydrocarbon being present if desired.  Tables are given listing the starting materials and molar ratios for the preparation of numerous salts or complexes, i.e. salts wherein the carboxy radicals are in excess of the conventional basicity of the amino radicals, salt complexes being apparently related to the presence of a tertiary amine radical. The polyamino reactants include the preferred cyclic amidines, and other amino and amino-amide compounds, the monocarboxy acids include saturated and unsaturated fatty acids, and the other acids include di-, tri-, and tetra-carboxy and mixtures thereof.  The salts are added to hydrocarbons. e.g. gasoline, and oils in amounts of 5-50 parts per million and prevent corrosion and rusting both in presence and absence of oxygen.