This invention relates to aqueous compositions which contain a metal free thiophosphorus acid ester or salts thereof which contain at least one hydrocarbyl terminated oxyalkylene group and methods of using the same.
An ongoing problem in the area of lubricating machinery is improving the water based lubricant""s ability to prevent metal-on-metal contact. Previously, phosphorus esters were used, often in combination with other additives, to provide antiwear and extreme pressure protection to lubricants. It would be advantageous to have additives which improve the antiwear and extreme pressure protection of the aqueous lubricants.
This invention relates to an aqueous composition comprising water, a surfactant or thickener, and at least one metal-free thiophosphorus acid ester, at least one amine salt of the thiophosphorus acid ester, or a mixture thereof, wherein the thiophosphorus acid ester contains at least one hydrocarbyl terminated oxyalkylene group, at least one hydrocarbyl terminated polyoxyalkylene group, or a mixture thereof. The aqueous compositions have improved antiwear/extreme pressure properties and improved antioxidation properties. In these compositions, the thiophosphorus acid esters and their salts act as antiwear agents and rust inhibitors.
The term xe2x80x9chydrocarbylxe2x80x9d includes hydrocarbon as well as substantially hydrocarbon groups. Substantially hydrocarbon describes groups which contain heteroatom substituents that do not alter the predominantly hydrocarbon nature of the substituent. Examples of hydrocarbyl groups include the following:
(1) hydrocarbon substituents, i.e., aliphatic (e.g., alkyl or alkenyl) and alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, aromatic-, aliphatic- and alicyclic-substituted aromatic substituents and the like as well as cyclic substituents wherein the ring is completed through another portion of the molecule (that is, for example, any two indicated substituents may together form an alicyclic radical);
(2) substituted hydrocarbon substituents, i.e., those substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon nature of the substituent; those skilled in the art will be aware of such groups (e.g., halo (especially chloro and fluoro), hydroxy, mercapto, nitro, nitroso, sulfoxy, etc.);
(3) heteroatom substituents, i.e., substituents which will, while having a predominantly hydrocarbon character within the context of this invention, contain an atom other than carbon present in a ring or chain otherwise composed of carbon atoms (e.g., alkoxy or alkylthio). Suitable heteroatoms will be apparent to those of ordinary skill in the art and include, for example, sulfur, oxygen, nitrogen and such substituents as, e.g. pyridyl, furyl, thienyl, imidazolyl, etc.
In general, no more than about 2, preferably no more than one heteroatom substituent will be present for every ten carbon atoms in the hydrocarbyl group. Typically, there will be no such heteroatom substituents in the hydrocarbyl group. Therefore, the hydrocarbyl group is hydrocarbon.
The thiophosphorus acid ester is generally present in an amount to improve the antiwear or extreme pressure properties of the aqueous compositions. In one embodiment, the thiophosphorus acid ester is present in an amount from about 0.01% up to about 10%, or from about 0.05% or up to about 4%, or from about 0.08% up to about 3%, or from 0.1% to about 2% by weight. Here, as well as elsewhere in the specification and claims, the range and ratio limits may be combined.
Thiophosphorus Acid Esters
As described above, the thiophosphorus acid ester has at least one group which is a hydrocarbyl terminated oxyalkylene group, or salts of the thiophosphorus acid esters. In one embodiment, the thiophosphorus acid esters are free of metal, e.g. ashless. The thiophosphorus acid esters or their salts may have one, two or three hydrocarbyl terminated oxyalkylene groups. Preferably, the thiophosphorus acid esters or salts have one or two, more preferably two hydrocarbyl terminated oxyalkylene groups, or a mixture of compounds having one, two or three hydrocarbyl terminated oxyalkylene groups. In one embodiment, the thiophosphorus acid esters and/or the aqueous compositions are free of dithiophosphorus acid esters and their salts, such as metal (e.g. zinc) or amine salts.
The hydrocarbyl moiety of the hydrocarbyl terminated oxyalkylene group generally contains up to about 30, or up to about 24, or up to about 18 carbon atoms. The hydrocarbyl moiety typically contains at least 1, or at least about 6, or at least about 8 carbon atoms. Examples of hydrocarbyl moieties include octyl, nonyl, decyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, docosyl, tetracosyl, etc. In one embodiment, the hydrocarbyl moiety is free of sulfur. In another embodiment, the hydrocarbyl moiety is aliphatic.
The oxyalkylene moiety typically contains from 1 to about 18 carbon atoms, preferably from about 2 to about 8, more preferably two or three carbon atoms. The hydrocarbyl terminated oxyalkylene group may contain from one to about 40 oxyalkylene moieties. In one embodiment, the hydrocarbyl terminated oxyalkylene group has from about 2 to about 15, or from about 2 to about 10, or from about two to about three oxyalkylene moieties. In one embodiment, the number of oxyalkylene groups is an average. In one embodiment, the oxyalkylene groups are derived from alkylene oxides, such as those described herein (e.g. ethylene oxide, propylene oxide, butylene oxide, etc.)
Hydrocarbyl terminated oxyalkylene groups are derived from hydrocarbyl terminated oxyalkylenes. The hydrocarbyl terminated oxyalkylene may be prepared by treatment of an alcohol, a phenol, an amine, such as those discussed below, including a monoamine, or a mercaptan, such as a C1-30 or C1-18 mercaptan, with at least one alkylene oxide, preferably an alkylene oxide having from one to about eight carbon atoms. Examples of alkylene oxides include ethylene oxide, propylene oxide, and butylene oxide. Preferably the hydrocarbyl terminated oxyalklyene is an alkyl terminated oxyalkylene. The alkyl terminated polyoxyalkylenes are available commercially under such trade names as xe2x80x9cCARBOWAX(copyright)xe2x80x9d and xe2x80x9cTERGITOL(copyright)xe2x80x9d from Union Carbide, xe2x80x9cTRITON(copyright)xe2x80x9d from Rohm and Haas Company, xe2x80x9cALFONIC(copyright)xe2x80x9d from Vista Chemicals Company, xe2x80x9cGENEPOL(copyright)xe2x80x9d from Hoechst Celanese Corporation, and xe2x80x9cNEODOL(copyright)xe2x80x9d from Shell Chemical Company. The TERGITOLS are identified as polyethylene glycol ethers of primary or secondary alcohols. Particularly preferred TERGITOL alkyl terminated oxyalkylenes are the TERGITOL(copyright) 15-S Series of secondary polyethylene glycol ethers. Examples of this series include TERGITOL 15-S-3, TERGITOL 15-S-5, TERGITOL 15-S-7, TERGITOL 15-S-9, TERGITOL 15-S-12, TERGITOL 15-S-15, TERGITOL 15-S-20, TERGITOL 15-S-30, and TERGITOL 15-S-40, wherein the last number of the series refers the average number of oxyethylene moieties in the ethers. The GENAPOL ethoxylated alcohols are synthetic or natural linear alcohols which are treated with ethylene oxide. An example of one of these alcohols is GENAPOL(copyright) 24-L-3, which is a C12-14 synthetic alcohol treated with about three moles of ethylene oxide. The TRITON materials are identified generally as polyethoxylated alcohols or phenols. The ALFONIC materials are identified as ethoxylated linear alcohols which may be represented by the general structural formula,
CH3(CH2)dCH2(OCH2CH2)eOH,
wherein d varies between 4 and 16 and e is a number between about 3 and about 11. Specific examples of ALFONIC(copyright) ethoxylates characterized by the above formula include ALFONIC 1012-60 wherein d is about 8 to 10 and e is an average of about 5 to 6; ALFONIC 1214-70 wherein d is about 10-12 and e is an average of about 10 to about 11; ALFONIC 1412-40, wherein d is about 10-12 and e is an average of about 2.5; ALFONIC 1412-60 wherein d is from 10-12 and e is an average of about 7; and ALFONIC 1218-70 wherein d is about 10-16 and e is an average of about 10 to about 11.
The NEODOL(copyright) ethoxylates are ethoxylated alcohols wherein the alcohols are a mixture of alcohols containing from about 12 to about 15 carbon atoms, and the alcohols are partially branched chain primary alcohols. The ethoxylates are obtained by reacting the alcohols with an excess of ethylene oxide, such as from about 3 to about 12 or more moles of ethylene oxide per mole of alcohol. For example, NEODOL ethoxylate 23-6.5 is a partially branched chain alcoholate of 12 to 13 carbon atoms with an average of about 6 to about 7 ethoxy units.
In one embodiment, the metal-free thiophosphorus acid ester is represented by the following formula 
wherein X1, X2, and X3 are oxygen or sulfur, provided that at least one of X1, X2, and X3 is sulfur; R1 is a hydrocarbyl group; R2 is an alkylene group; R3 is hydrogen or a hydrocarbyl group; x is a number from 1 to about 40; and a is 0, 1, or 2, or at least one salt of the thiophosphorus acid ester. In one embodiment, X1 is sulfur, and X2 and X3 are oxygen and a is one. R1 and R3 each independently the same as the description of the hydrocarbyl moiety above. The values for x are the same the number of oxyalkylene groups described above.
The thiophosphorus acid ester which contains at least one hydrocarbyl terminated oxyalkylene group may be prepared by transesterifying a phosphite with one or more oxyalkylene containing compounds. In one embodiment, the thiophosphorus acid esters are prepared in the absence of unsaturated fatty acids or esters. The resulting intermediate is reacted with sulfur or a sulfur source. The phosphite may be a di- or trihydrocarbyl phosphite. Preferably each hydrocarbyl group contains from 1 to about 24 carbon atoms, more preferably from 1 to about 18 carbon atoms, and more preferably from 1 to about 8 carbon atoms. Each hydrocarbyl group may be independently alkyl, alkenyl, or aryl, preferably alkyl.
The sulfur source may be any of a variety of materials which are capable of supplying sulfur to the reaction. Examples of useful sulfur sources include sulfur, sulfur halides, combinations of sulfur with hydrogen sulfide or sulfur oxide with hydrogen sulfide, and various sulfur containing organic compounds. Elemental sulfur is a preferred sulfur source. The sulfur halides include sulfur monochloride, sulfur dichloride, etc. The sulfur sources may also be sulfur containing organic compounds, such as aromatic and alkyl sulfides, dialkenyl sulfides, sulfurized olefins, sulfurized oils, sulfurized fatty acid esters, sulfurized aliphatic esters of olefinic mono- or dicarboxylic acids, diester sulfides, sulfurized Diels-Alder adducts and sulfurized terpenes. U.S. Pat. No. 4,755,311 discloses various sulfur sources capable of supplying sulfur to reaction. This patent is incorporated by reference for its disclosure of sulfur sources. The preparation of monothiophosphoric acid esters is disclosed in U.S. Pat. No. 4,755,311 and PCT Publication WO 87/07638, which are incorporated herein by reference for their disclosure of monothiophosphoric acids, sulfur sources, and the process for making monothiophosphoric acid esters.
As described above, salts of the thiophosphorus acid esters having at least one hydrocarbyl terminated oxyalkylene group may be used in the aqueous composition. The salts are formed by reacting the thiophosphorus acid ester with ammonia or an amine. The salts may be formed separately and then added to the lubricating composition. Alternatively, the salts may also be formed in situ when an acidic thiophosphorus acid ester is blended with other components to form a fully formulated lubricating composition. The phosphorus acid ester may then form salts with basic materials which are in the lubricating composition or functional fluid composition such as basic nitrogen containing compounds (e.g., basic nitrogen containing dispersants or basic amines).
The amine salts of the thiophosphorus acid esters may be formed from ammonia, or a primary, secondary or tertiary amine, a dispersant or mixtures thereof. These amines can be monoamines or polyamines. Useful amines include those disclosed in U.S. Pat. No. 4,234,435 at Col. 21, line 4 to Col. 27, line 50, this section of this reference being incorporated herein by reference.
The monoamines generally contain from 1 to about 24 carbon atoms, with from 1 to about 12 carbon atoms being preferred, with from 1 to about 6 being more preferred. Examples of monoamines include methylamine, ethylamine, propylamine, butylamine, octylamine, and dodecylamine. Examples of secondary amines include dimethylamine, diethylamine, dipropylamine, dibutylamine, methylbutylamine, ethyl-hexylamine, etc. Tertiary amines include trimethylamine, tributylamine, methyldiethylamine, ethyldibutylamine, etc.
In one embodiment, the amine may be a hydroxyhydrocarbylamine. Typically, the hydroxyamines are primary, secondary or tertiary alkanolamines or mixtures thereof. Such amines can be represented by the formulae: H2xe2x80x94Nxe2x80x94Rxe2x80x2xe2x80x94OH, H(Rxe2x80x21)Nxe2x80x94Rxe2x80x2xe2x80x94OH, and (Rxe2x80x21)2xe2x80x94Nxe2x80x94Rxe2x80x2xe2x80x94OH, wherein each Rxe2x80x2 is independently a hydrocarbyl group having from one to about eight carbon atoms or hydroxyhydrocarbyl group having from one to about eight carbon atoms, or from one to about four, and Rxe2x80x2 is a divalent hydrocarbyl group of about two to about 18 carbon atoms, or from two to about four. The group xe2x80x94Rxe2x80x2xe2x80x94OH in such formulae represents the hydroxyhydrocarbyl group. Rxe2x80x2 can be an acyclic, alicyclic or aromatic group. Typically, Rxe2x80x2 is an acyclic straight or branched alkylene group such as an ethylene, 1,2-propylene, 1,2-butylene, 1,2-octadecylene, etc. group. Where two Rxe2x80x21 groups are present in the same molecule they can be joined by a direct carbon-to-carbon bond or through a heteroatom (e.g., oxygen, nitrogen or sulfur) to form a 5-, 6-, 7- or 8-membered ring structure. Examples of such heterocyclic amines include N-(hydroxyl lower alkyl)-morpholines, -thiomorpholines, -piperidines, -oxazolidines, -thiazolidines and the like. Typically, however, each Rxe2x80x21 is independently a methyl, ethyl, propyl, butyl, pentyl or hexyl group. Examples of these alkanolamines include mono-, di-, and triethanolamine, diethylethanolamine, ethylethanolamine, butyldietha-nolamine, etc.
The hydroxyhydrocarbylamines may also be an ether N-(hydroxyhydrocarbyl)amine. These are hydroxypoly(hydrocarbyloxy) analogs of the above-described hydroxyamines (these analogs also include hydroxyl-substituted oxyalkylene analogs). Such N-(hydroxyhydrocarbyl) amines can be conveniently prepared by reaction of one or more of the above epoxides with above described amines and may be represented by the formulae: H2Nxe2x80x94(Rxe2x80x2O)xxe2x80x94H, H(Rxe2x80x21)Nxe2x80x94(Rxe2x80x2O)xxe2x80x94H, and (Rxe2x80x21)2Nxe2x80x94(Rxe2x80x2O),xe2x80x94H, wherein x is a number from about 2 to about 15 and R1 and Rxe2x80x2 are as described above. Rxe2x80x21 may also be a hydroxypoly(hydrocarbyloxy) group.
In another embodiment, the amine is a hydroxyhydrocarbylamine which may be represented by the formula 
wherein R1 is a hydrocarbyl group containing from about 6 to about 30 carbon atoms; R2 is an alkylene group having from about two to about twelve carbon atoms, preferably an ethylene or propylene group; R3 is an alkylene group containing from 1 up to about 8, or from 1 up to about 5 carbon atoms; y is zero or one; and each z is independently a number from zero to about 10, with the proviso that at least one z is zero.
Useful hydroxyhydrocarbyl amines where y in the formula is zero include 2-hydroxyethylhexylamine; 2-hydroxyethyloctylamine; 2-hydroxyethylpentadecylamine; 2-hydroxyethyloleylamine; 2-hydroxyethylsoyamine; bis(2-hydroxyethyl)hexylamine; bis(2-hydroxyethyl)oleylamine; and mixtures thereof. Also included are the comparable members wherein in the above formula at least one z is at least 2, as for example, 2-hydroxyethoxyethylhexylamine.
In one embodiment, the amine may be a hydroxyhydrocarbyl amine, where referring to the above formula, y equals zero. These hydroxyhydrocarbyl amines are available from the Akzo Chemical Division of Akzona, Inc., Chicago, Ill., under the general trade designations xe2x80x9cETHOMEENxe2x80x9d and xe2x80x9cPROPOMEENxe2x80x9d. Specific examples of such products include: ETHOMEEN C/15 which is an ethylene oxide condensate of a coconut fatty acid containing about 5 moles of ethylene oxide; ETHOMEEN C/20 and C/25 which are ethylene oxide condensation products from coconut fatty acid containing about 10 and 15 moles of ethylene oxide, respectively; ETHOMEEN O/12 which is an ethylene oxide condensation product of oleyl amine containing about 2 moles of ethylene oxide per mole of amine; ETHOMEEN S/15 and S/20 which are ethylene oxide condensation products with stearyl amine containing about 5 and 10 moles of ethylene oxide per mole of amine, respectively; ETHOMEEN T/12, T/15 and T/25 which are ethylene oxide condensation products of tallow amine containing about 2, 5 and 15 moles of ethylene oxide per mole of amine, respectively; and PROPOMEEN O/12 which is the condensation product of one mole of oleyl amine with 2 moles propylene oxide.
The amine may also be a polyamine. The polyamines include alkoxylated diamines, fatty polyamine diamines, alkylenepolyamines, hydroxy containing polyamines, condensed polyamines, and heterocyclic polyamines. Commercially available examples of alkoxylated diamines include those amines where y from above is one. Examples of these amines include ETHODUOMEEN T/13 and T/20 which are ethylene oxide condensation products of N-tallowtrimethylenediamine containing 3 and 10 moles of ethylene oxide per mole of diamine, respectively.
In another embodiment, the polyamine is a fatty diamine. The fatty diamines include mono- or dialkyl, symmetrical or asymmetrical ethylenediamines, propanediamines (1,2, or 1,3), and polyamine analogs of the above. Suitable commercial fatty polyamines are DUOMEEN C (N-coco-1,3-diaminopropane), DUOMEEN S (N-soya-1,3-diaminopropane), DUOMEEN T (N-tallow-1,3-diaminopropane), and DUOMEEN O (N-oleyl-1,3-diaminopropane). xe2x80x9cDUOMEENSxe2x80x9d are commercially available from Armak Chemical Co., Chicago, Ill.
The amine may be an alkylenepolyamine. Alkylenepolyamines are represented by the formula H(R1)N-(Alkylene-N)nxe2x80x94(R1)2, wherein each R1 is independently hydrogen; or an aliphatic or hydroxy-substituted aliphatic group of up to about 30 carbon atoms; n is a number from 1 to about 10, or from about 2 to about 7, or from about 2 to about 5; and the xe2x80x9cAlkylenexe2x80x9d group has from 1 to about 10 carbon atoms, or from about 2 to about 6, or from about 2 to about 4. In another embodiment, R1 is independently a hydrocarbyl group having from one to about eight carbon atoms or hydroxyhydrocarbyl group having from one to about eight, or from one to about four carbon atoms. Such alkylenepolyamines include methylenepolyamines, ethylenepolyamines, butylenepolyamines, propylenepolyamines, pentylenepolyamines, etc. The higher homologs and related heterocyclic amines, such as piperazines and N-amino alkyl-substituted piperazines, are also included. Specific examples of such polyamines are ethylenediamine, triethylenetetramine, tris-(2-aminoethyl)amine, propylenediamine, trimethylenediamine, tripropylenetetramine, triethylenetetraamine, tetraethylenepentamine, hexaethyleneheptamine, pentaethylenehexamine, etc. Higher homologs obtained by condensing two or more of the above-noted alkyleneamines are similarly useful as are mixtures of two or more of the aforedescribed polyamines.
In one embodiment, the polyamine is an ethylenepolyamine. Such polyamines are described in detail under the heading Ethylene Amines in Kirk Othmer""s xe2x80x9cEncyclopedia of Chemical Technologyxe2x80x9d, 2d Edition, Vol. 7, pages 22-37, Interscience Publishers, New York (1965). Ethylenepolyamines are often a complex mixture of polyalkylenepolyamines including cyclic condensation products. Other useful types of polyamine mixtures are those resulting from stripping of the above-described polyamine mixtures to leave, as residue, what is often termed xe2x80x9cpolyamine bottomsxe2x80x9d. These alkylenepolyamine bottoms include cyclic condensation products such as piperazine and higher analogs of diethylenetriamine, triethylenetetramine and the like.
In another embodiment, the polyamines are hydroxy-containing polyamines. Hydroxy-containing polyamine analogs of the hydroxy monoamines, particularly alkoxylated alkylenepolyamines, e.g., N,Nxe2x80x2-(dihydroxyethyl)ethylenediamines can also be used. Such polyamines can be made by reacting the above-described alkyleneamines with one or more of the above-described alkylene oxides. Similar alkylene oxide- alkanolamine reaction products may also be used such as the products made by reacting the above described primary, secondary or tertiary alkanolamines with ethylene, propylene or higher epoxide in a 1.1 to 1.2 molar ratio. Reactant ratios and temperatures for carrying out such reactions are known to those skilled in the art. Specific examples of hydroxy-containing polyamines include N-(2-hydroxyethyl)ethylenediamine, N,Nxe2x80x2-bis(2-hydroxyethyl)ethylenediamine, 1-(2-hydroxyethyl)piperazine, mono(hydroxypropyl)-substituted tetraethylene-pentamine, N-(3-hydroxybutyl)tetramethylenediamine, etc. Higher homologs obtained by condensation of the above illustrated hydroxy-containing polyamines through amino groups or through hydroxy groups are likewise useful. Condensation through amino groups results in a higher amine accompanied by removal of ammonia, while condensation through the hydroxy groups results in products containing ether linkages accompanied by removal of water. Mixtures of two or more of any of the above described polyamines are also useful.
Another useful polyamine is a condensation reaction between at least one hydroxy compound with at least one polyamine reactant containing at least one primary or secondary amino group. The hydroxy compounds are preferably polyhydric alcohols and amines. The polyhydric alcohols are described below. In one embodiment, the hydroxy compounds are polyhydric amines. Polyhydric amines include any of the above-described monoamines reacted with an alkylene oxide (e.g., ethylene oxide, propylene oxide, butylene oxide, etc.) having from two to about 20 or from two to about four carbon atoms. Examples of polyhydric amines include diethanolamine, triethanolamine, tri-(hydroxypropyl)amine, tris-(hydroxymethyl)amino methane, 2-amino-2-methyl-1,3-propanediol, N,N,Nxe2x80x2,Nxe2x80x2-tetrakis(2-hydroxypropyl)ethylenediamine, and N,N,Nxe2x80x2,Nxe2x80x2-tetrakis(2-hydroxyethyl)ethylenediamine, preferably tris(hydroxymethyl)aminomethane (THAM).
Polyamines which may react with the polyhydric alcohol or amine to form the condensation products or condensed amines, are described above. Preferred polyamines include triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), and mixtures of polyamines such as the above-described xe2x80x9camine bottomsxe2x80x9d. The condensation reaction of the polyamine reactant with the hydroxy compound is conducted at an elevated temperature, usually from about 60xc2x0 C. to about 265xc2x0 C., or from about 220xc2x0 C. to about 250xc2x0 C. in the presence of an acid catalyst.
The amine condensates and methods of making the same are described in PCT publication WO86/05501 and U.S. Pat. No. 5,230,714 (Steckel) which are incorporated by reference for its disclosure to the condensates and methods of making. A particularly useful amine condensate is prepared from HPA Taft Amines (amine bottoms available commercially from Union Carbide Co. with typically 34.1% by weight nitrogen and a nitrogen distribution of 12.3% by weight primary amine, 14.4% by weight secondary amine and 7.4% by weight tertiary amine), and tris(hydroxymethyl)aminomethane (THAM).
In another embodiment, the polyamine is a heterocyclic polyamine. The heterocyclic polyamines include aziridines, azetidines, azolidines, tetra- and dihydropyridines, pyrroles, indoles, piperidines, imidazoles, di- and tetrahydroimidazoles, piperazines, isoindoles, purines, morpholines, thiomorpholines, N-aminoalkylmor-pholines, N-aminoalkylthiomorpholines, N-aminoalkylpiperazines, N,Nxe2x80x2-diaminoalkylpiperazines, azepines, azocines, azonines, azecines and tetra-, di- and perhydro derivatives of each of the above and mixtures of two or more of these heterocyclic amines. Preferred heterocyclic amines are the saturated 5- and 6-membered heterocyclic amines containing only nitrogen, oxygen and/or sulfur in the hetero ring, especially the piperidines, piperazines, thiomorpholines, morpholines, pyrrolidines, and the like. Piperidine, aminoalkyl substituted piperidines, piperazine, aminoalkyl substituted piperazines, morpholine, aminoalkyl substituted morpholines, pyrrolidine, and aminoalkyl-substituted pyrrolidines, are especially preferred. Usually the aminoalkyl substituents are substituted on a nitrogen atom forming part of the hetero ring. Specific examples of such heterocyclic amines include N-aminopropylmorpholine, N-aminoethylpiperazine, and N,Nxe2x80x2-diaminoethylpiperazine. Hydroxy heterocyclic polyamines may be used and include N-(2-hydroxyethyl)cyclohexylamine, 3-hydroxycyclopentylamine, parahydroxyaniline, N-hydroxyethylpiperazine, and the like.
In another embodiment, the salts of the thiophosphorus acid esters are prepared by reacting the thiophosphorus acid ester with an amine dispersant. The amine dispersant may be prepared by reacting a hydrocarbyl-substituted carboxylic acylating agent with one or more of the above described polyamines. The hydrocarbyl group may be derived from a polyalkene and may have a number average molecular weight from about 500 to about 5000 or from about 700 to about 2500. The polyalkenes are prepared from olefins set containing from about 2 to about 12 carbon atoms, or from about 2 to about 8 carbon atoms. Preferred hydrocarbyl group is derived from a polyisobutylene. The hydrocarbyl-substituted carboxylic acylating agents may be monocarboxylic or dicarboxylic acylating agents such as those derived from the reaction product of a polyalkene with a monocarboxylic acid such as acrylic acid, methacrylic o acid, itaconic acid, etc or reaction with a dicarboxylic acid such as maleic anhydride, maleic acid, fumaric acid, etc. These dispersants are described in U.S. Pat. No. 3,219,666 and U.S. Pat. No. 4,234,435, the disclosures of which are incorporated by reference for their teachings of hydrocarbyl-substituted carboxylic acylating agents, amines and methods of preparing the dispersants.