THIO-BIS-(HYDROCARBON-BISOXAZOLINES) AND ANALOGS, PROCESS FOR THEIR PREPARATION AND THEIR USE AS OLEAGINOUS ADDITIVES

Abstract: Thio-bis-(hydrocarbon-bisoxazolines) and analogs, which are the reaction products of thio-bis-(hydrocarbon-­ substituted dicarboxylic acid material), for example, thio-bis­ (polyisobutenyl succinic anhydride), with about 1 to 4 moles of 2,2-disubstituted-2-amino-1-alkanols, such as tris -(hyd­ roxymethyl) amino-methane (THAM), and their derivatives are useful additives in oleaginous compositions, such as sludge dispersants for lubricating oil or anti-corrosion agents for fuels.

Description: The present invention concerns oil-soluble thio-bis (hydrocarbon-bisoxazolines) and their analogs, their method of preparation and the utility of said oxazolines in hydrocarbon fuel and lubricating systems as highly stable anticorrosion agents and/or sludge dispersants. During the past decade, ashless sludge dispersants have become increasingly important, primarily in improving the performance of lubricants and gasoline in keeping the engine clean of deposits, and permitting extended crankcase oil drain periods. Most commercial ashless dispersants fall into several general categories. In one category, a polyamine is linked to a long-chain hydrocarbon polymer, such as polyisobutylene, through a dicarboxylic acid material, such as succinic anhydride, by forming amide or imide linkages, such as described in U.S. Patent 3,172,892. United Kingdom Specification 809,001 teaches corrosion inhibitors comprising a multiple salt complex derived from the reaction product of hydrocarbyl-substituted dicarboxylic acids and hydroxy amines (including 2-amino-2methyl-1,3-propanediol [AMPD]) and tris-hydroxymethylamino- methane (THAM) further complexed with mono-and polycarboxylic acids (see Examples 17-19). United Kingdom Specification 984,409 teaches ashless, amide/imide/ester type lubricant additives prepared by reacting an alkenyl succinic anhydride, said alkenyl group having 30 to 700 carbon atoms, with a hydroxy amine including THAM. German OS 2512201 teaches reacting long-chain hydrocarbon-substituted succinic anhydride with 2, 2-disubstituted-2-amino-l-aikanol to produce mono- and bisoxazoline products. Thio-bis-(alkyl lactone oxazolines), useful as oleaginous additives, and chlorinecontaining thio-bis-adducts of sulfur chlorides with octenyl succinic anhydride are disclosed in U.S.P. 4,062,786. It has now been discovered that the dehydrochlorinated thio-bis-adducts or acylating agents obtained by the reaction of sulfur halides with hydrocarbyl-substituted dicarboxylic anhydrides or acids or esters can be further reacted with 2,2-disubstituted-2-amino l-alkanols to form oxazolines. The reaction of the thio-bis-adducts or acylating agents is carried out using 1 to 4, preferably 2 to 4 molar equivalents of the alkanol per molar equivalent of said adduct. The most preferred proportions comprise 4 moles of the alkanol per mole of said acylating agent thereby forming a thio-bis-(hydrocarbon-bis-oxazoline) having about 4 oxazoline groups per molecule. These oxazolines are highly stable additives with outstanding varnish inhibition. A preferred member of this novel class of additives can be represented by the formula: EMI2.1 wherein R is selecte from the group consisting of hydro- gen and alkyl radicals containing from 1 to 400 carbons, X is selected from the group consisting of an oil or hy droxyalkyl group and at least one of the X substtuents and preferably both of the X substituents being 2 hydroxy alkyl group of the structure -(CIi,2)10H where n is 1 to 3, and Y is selected from dhe croup consisting of -S-, -S-S-, S=0 (sulfinyl), 5 S02 (sulfonyl), -Se- (seleno) and -S- (CH2)z -S- wherein z is a number from 2 to 1C Preferred herein is thio-bis-(polyisobutenyl-bisoxazoline) of number average molecular weight ranging from about 400 to 100,000 prepared by the reaction of thio-bis (acylating reagent), e.g. thio-bis-(polyisobutenyl succinic anhydride), with tetramolar proportions of tris-Chydroxy- methyl) amino-methane (hereinafter designated also as THAM). The reaction is carried out at a temperature from about 100 to 240 C., preferably 150-180 C, until about six moles of H20 per mole of the thio reactant are removed from the reaction. The novel compounds described above as effective detergents in lubricating oil compositions are also useful as detergents in fuel compositions, such as burner fuel compositions, and motor fuel compositions, for example, in gasolines and in diesel fuels. The hydrocarbon-soluble compounds have at least 8 carbons in the aliphatic hydrocarbyl group of the thio-bis (acylating reagent) converted into bisoxazoline rings as a result of the reaction of said thio-bis-(hydrocarbon substituted dicarboxylic acid material) and about tetramolar amounts of a 2,2-disubstituted-2-amino-l-alkanol having 1 to 3 hydroxy groups and containing a total of 4 to 8 carbons. The preparacion of the mono- or dithio-bis-(alkene dioic acid or anhydride or ester) or dithio-bis-(alkane dioic acid or anhydride or ester) acylating agents involve the sulfur halide coupling or bis-sulfenyl halide-induced coupling or the oxidative coupling of H2S or thioacid ad ducts of an olefin diacid. The olefin diacidmaterial is read obtained via the reaction of an olefin or a chlorinated olefin with an unsaturated C4 to C10 dicarboxylic acid, anhyd- ride or ester thereof, such as fumaric acid, itaconic acid, maleic acid, maleic anhydride, dimethyl funarate, etc. The dicarboxylic acid material formed via the Ene reaction of an olef in with maleic anhydride can be illustrated as an alkenyl-substituted anhydride which may contain a single alkenyl radical or a mixture of alkenyl radicals variously bonded to the cyclic succinic anhydride group, and is under stood to comprise such structures as: EMI4.1 with then 0-unsaturated isomers predominating and wherein R # may be hydrogen or hydrocarbyl containing from 5 to about carbons, preferably from about 16 to about 400 carbons and optimally from about 60 to about 100 carbons. The anhydride can be obtained by well-known methods, such as the reaction between an olefin and maleic anhydride or halosuccinic anhyd ride or succinic ester. In branched olefins, particularly branched polyolefins, R may be hydrogen, methyl or a longchain hydrocarbyl group. However, the exact structure may not always be ascertained and the various R groups cannot always be precisely defined in the Ene products from polyolefins and maleic anhydride. Suitable olefins include butene, isobutene, pentene, decene, dodecene, tetradecene, hexadecene, octadecene, eicosene, and polymers of propylene, butene, isobutene, pet- tene, decene and the like, and halogen-containing olefins. The olefins may also contain cycloalkyl and aromatic groups. With 2-chioromaleic anhydride and related acylating agents, alkenylmaleic anhydrideKreactants are formed. Bridging of these products with YC12 also afford useful precursors. Preferred olefin polymers for reaction with the unsaturated dicarboxylic acids are polymers comprising a major molar amount of C2-C5 monoolefin, e.g., ethylene, propylene, butylene, isobutylene and pentene. The polymers can be homopolymers, such as polyisobutylene, as well as copolymers of two or more of such olefins such as copolymers of ethylene and propylene, butylene and isobutylene, propylene and isobutylene, etc. The olefin polymers will usually have number average molecular weights (EA). within the range of 500 and about 140,000;'more usually between about 700 and about 10,000. Particularly useful olefin polymers have (Mn) within the range of about 70C and about 5,000 with approximately one terminal double bond per polymer chain. An especially valuable starting material for a highly potent dispersant additive are polyalkenes, e.g. polypropylene and polyisobutylene, having about 90 carbons. The dicarboxylic acid materials (Diels-Alder ad- ducts) formed via the reaction of a chlorinated olefin with maleic anhydride also useful in the present invention, cAn be illustrated in part, by the following structures: EMI5.1 where R is as previously defined. Useful chlorinated olefins include chlorinated di-isobutylene, tri-isobutylene, polyisobutylene, tetrapro?ylene, polyisopropylene, and alkenes which upon halogenation characteristically gives allylic halide structures. The bridging or coupling of the precursor acylating agents can be achieved by (i) addition of sulfur halides or bis-sulfenyl halides or alkyl sulfenate/HCl reagent to unsaturated diacid anhydrides, (ii) the oxidative coupling of unsaturated diacids or anhydrides or esters previously thiylated with H2S or R1C (=0) SH, where R1 represents a C1-C5 alkyl group, or (iii) reaction of ct, - -alkane-dithiols, H2S, or a suitable thiylating agent, with epoxidized or halogenated alkene dioic acid or anhydride materials. The preferred method to bridged acylating agents involves the reaction of sulfur halides, bis-sulfenyl halides or a sulfenate ester-HCl reagent with unsaturated diacid anhydrides in the temperature range of -60 C to about 100"C, optimally from about 10"C to 500 C. If desired, solvents comprising hydrocarbons, such as pentane, hexane, heptane, cyclohexane, mineral oil; halocarbons such as methylene chloride, chloroform, carbon tetrachloride, aromatics such as toluene, chlorobenzenes, xylene; ethers, such as diethyl ether and tetrahydrofuran(THF); and, acids such as acetic, prop ironic and trifluoroacetic acid, can be used in favorably controlling viscosity and reaction temperature. Usually, the sulfur halide is added dropwise to an unsaturated diacid anhydride, preferably diluted in an inert diluent. With reactive diluents and unsaturates such as polyisobutylene, sufficient sulfur halide must be added to effect complete bridging of the olefin diacid anhydride reactants. When the addition of one mole of sulfenyl halide to 2 moles of alkene dioic acid anhydride is conducted a. low temperatures, e.g. -60 C to about 20"C, a discrete YCl2-anhydride adduct forms which upon dehydrohalogenation gives a thio-bis-acylating agent as depicted in the equation EMI7.1 with R and Y being the same as previously defined. Increasing the bridging temperature above about 50 C., and branching in the hydrocarbyl portion of the alkene dioic anhydride tend to accelerate the elimination of HC1 from YC12-alkene dioic anhydride adduct. Since unsaturated bridged products can be further sulfenylated with YC12 reagent (re-addition), it becomes necessary in some cases, to modify the theoretical 2:1 stoichiometry to effect complete bridg-ing. Accordingly, at higher temperatures, i.e. from 50 -100 C., ratios in the range of 1.5:1 to 1:1 may be required to realize higher conversions to bridged structures due to re-addition reactions, and the partial thermal decomposition of the sulfur halide reactant at elevated temDeratures. While more sulfur halide reagent becomes necessary to achieve coupling, the additional sal- fur incorporated into the dispersant precursor (and occasionally th & diluent) tends to endow the resulting thioether products with enhanced oxidative stability. As indicated above, sulfur halides including SC12, S2C12 and alkyl sulfenate ester/HCl reagent are suwt- able bridging agents. Bis-sulfenyl halides derived from alkane, heteroalkane, aromatic, heteroaromatic, and heterocyclic radicals such as EMI8.1 are also useful coupling agents. Oxidation of the monothio ether products provides access to useful sulk oxide and sulfone derivatives. A var- ety ci inorganic and organic oxidizing agents can be used to effect these conversions including hydrogen peroxide, per- acids, hydroperoxides, e.g. t-butyl hydroperoxide, chlorine, positive halogen reagents, nitric acid, oxides of nitrogen, oxygen, ozone and metal oxides. The preferred oxidant is hydrogen peroxide usually in acetic acid and as necessary in an aromatic solvent, e.g. toluene. Oxidation with ecuimolar quantities of reactants at about 0 to 600C. provides the sulfoxide in excellent yield. A 2:1 molar ratio of peroxide to said thio ether product produces the sulk one derviative. The peroxide oxidation of sulfides to sulk ones is ref erablv carried out in the presence of cata- lyric amounts of conventional oxidation catalysts such as tungsten, molybdenum, e.g. molybdenyl acetylacetonate, or vanadium salts. The amino alcohol used to react with the thio-bi: (hydrocarbon substituted dicarboxylic acid material) is a 2,2-disubstituted-2-amino-1-alkanol containing a total of to 8 carbon atoms, and which can be represented by the for; EMI8.2 wherein X is an alkyl or hydroxy alkyl group, with at leas one of the X substituents, and preferably both of the X substituents being a hydroxy alkyl group of the structure (CH2)nOH, wherein n is 1 to 3. Examples of such 2,2-disubstituted amino alkanol include 2-amino-2-methyl-1,3-propanediol, 2-amino-2-(hydro methyl)-1,3-propanediol (also known as tris-hydroxy aminomethane or TRAM), 2-amino-2-ethyl-l, 3-propanedlol, etc. Because of its effectiveness availability, and cost, the THAM is particularly preferred. By sharp contrast, it has been found that other amino alcohols such as ethanolamine, propanolamine and butanolamine which lack, 2,2-disubstitution, do not afford oxazoline products. The formation of the novel oxazoline materials z substantial yield, can be effected by adding from one to four moles of the aforesaid 2,2-disubstituted-2-ino-l- alkanol per mole of the thio-bis-(acylating reagent) wide or without an inert diluent, and heating the mixture at 100-2400C., preferably 170-2200C. until reaction is com- plete by infrared analysis of the product showing maxi=ai absorption for oxazoline and/or until evolution of water ceases. Although not necessary, the presence of small amounts such as .01 to 2 wt.% preferably 0.1 to 1 wt.%, based on the weight of the reactants, of a metal salt can be usea in the reaction mixture as 2 catalyst. The metal catalyst can later be removed by filtration or by washing o hydrocarbon solution of the product with a lower alcohol, such as methanol, ethanol, isopropanol, etc., or an alcohol/ water solution. Alternatively, the metal salt can be left in the reaction mixture, as itappears to become stably dispersed, or dissolved, in the reaction product, and. depending on the metal, it may even contribute performance benefits to the oil or gasoline. This is believed to occur with the use of zinc catalysts in lubricants. Inert solvents which may be used in the above re action include hydrocarbon oils, e.g. mineral lubricating oil, kerosene, neutral mineral oils, xylene, halogenated hydrocarbons, e.g., carbon tetrachloride, dichlorobenzene, tetrahydrofuran, etc. Metal salts that may be used as catalysts in the invention include carboxylic acid salts of Zn, Co, Mn and Fe. Metal catalysts derived from strong acids (C1, sul fonic acid, n'2SO4, HNO3, etc.) and bases, tend to diininish the yield of the oxazoline products and instead favor imide or ester formation. For this reason, these strong acia catalysts or base catalysts are not preferred and usually will be avoided. The carboxylic acids used to prepare the desired catalysts, include C1 to Clue, e.g., C1 to C8 acids, such as the saturated or unsaturated mono- and dicarboxylic aliphatic hydrocarbon acids, particularly fatty acids. Specific examples of such desired carboxylic acid salts include zinc acetate, zinc formate, zinc propionate, zinc stearate, manganese(ous) acetate, iron tartrate, cobalt(ous) acetate, etc. Completion of the oxazoline reaction can be readily ascertained by using periodic infrared spectral analysis for maxim21 oxazoline formation (C=N absorption band at 6.G microns) and/or by the cessation of water evoolution. In another embodiment of the invention the thiobis-(acylating reagent) is treated with less than a stoichiometric quantity, i.e. less than four molar equivalents e.g. 1 to 3, preferably 2 to 3, molar equivalents of TRAM, to provide oxazoline-ester dispersents which are useful in themselves or can be converted to other classes of novel dispersants by treatment with polyamines to form oxazoline imidei amide products or reaction with polyols, such as pentaery thritol, preferably using ratios of 1 molar equivalent of saic oxazoline-ester dispersant per 1 to 2 molar equivalents of pentaerythritol, to form novel oxazoline polyol dispersants and if desired finally reacted with alkylene oxides to form alkoxylated derivatives thereof having wide utility as additives. It is to be understood that the oxazoline products of the invention can be both molybdated with molybdenum to enhance their lubricity activity and borated with boron to enhance the additives' anticorrosion and/or varnish inhibition activities. 'this" as the term is generically used in this disclosure encompasses sulfur and its congenor, i.e. selenium The oil-soluble oxazoline reaction products of the invention can be incorporated in a wide variety of oleaginous compositions. They can be used in lubrica.ing oil composi tins, such as automotive crankcase lubricating oils, automatic transmission fluids, etc., in concentrations generally within the range of about O.G1 to 20 wt.%, e.g. 0.1 to 10 weight percent, preferably .3 to 3.0 weight percent, of the total composition. The lubricants to which the oxazoline products can be added include not only hydrocarbon oils derived from petroleum but also include synthetic lubricating oils such as polyethylene oils; alkyl esters of dicarboxylic acid; complex esters of dicarboxylic acid, polyglycol and alcohol; alkyl esters of carbonic or phosphoric acids; polysilicones; fluorohydrocarbon oils; mixtures of mineral lubricating oil and synthetic oils in any proportion, etc. When the products of this invention are used as multifunctional additives having detergent and antirust properties in petroleum fuels, such as gasoline, kerosene, diesel fuels, No. 2 fuel oil and other middle distillates, a concentration of the additive in the fuel in the range of 0,001 to 0.5 weight percent, based on the weight of the total composition, will usually be employed. When used as an antifoulant in oil streams in refinery operations to prevent fouling of process equipment such as heat exchangers or in turbine oils, about 0.001 to 2 2 wt.% will generally be used. The additive may be conveniently dispensed as a concentrate comprising 20 to 90 parts, preferably 30 to 60, parts by weight, of the additive dissolved in a mineral lubricating oil. EXAMPLE 1 - Dithio-bis-[polysobutenyl-bis-(5,5,-bis- methylol-2-oxazoline) Two-hundred grams (ca 0.154 mole) of a polyisobutenyl succinic anhydride (prepared via the reaction of polyisobutene and maleic anhydride) having a (Mn) of 1330 and a Saponification Number of 72, were diluted with 100 mi of methylene chloride and stirred at room temperature under a nitrogen blanket. Then, 10.4g (ca 0.077 mole) of S2Cl2 were added dropwise for 2 period of half an hour. The reaction mixture was stirred at room temperature for about ten hours. One-half of this product was evaporated and the residue was sparged with nitrogen at 1500C. for four hours. The resulting dithio-bis-(polyisobutenyl succinic anhydride) adduct analyzed for 2.08 wt.% S and 0.15 wt.% C1. About 21g (ca 0.007 moles) of said adduct were diluted with an equal weight of mineral oil (Solvent 150 Neutral) and heated to 1200C. Then 0.lg of zinc acetate and 3.4c (0.028 mole) of THRUM were added. The reaction mixture was heated to 1800C. for 2 hours while sparging with nitrogen and filtered. The oil solution analyzed for 0.9 wt.E nitrogen. The infrared analysis confirmed the presence of the above-identified tetraoxazoline product. EXAMPLE 2-Dithio-bis-[polyisobutonyl-bis-(5,5-bis methylol- 2-oxazoline) 30g (ca 0.014 mole) of a dithio-bis-(polyiso- butenyl succinic anhydride) adduct derived from a polyisobutenyl succinic anhydride of (Mr) of 990 and a Sap. No. 107 and S2C12 were diluted with 32g of mineral oil (Solvent 150 Neutral) and heated to 1200C. Then 0.1c of zinc ci- acetate and 6.9g (ca 0.057 moles) of T were added. The reaction mixture was heated to 1800C. for two hours with nitrogen sparking and then filtered. The oil solution of the oxazoline product analyzed for 1.07 wt.% nitrogen. EXAMPLE 3 - thio-bis-[polyisobutenyl-bis-(5,5-bis methylol-2-oxazoline)] Five-hundred grams (ca 0,385 moles) cf polyisobutenylsuccinic anhydride having a (#m) of 775 and a Sap. Nc. of 84 were dissolved in 60 ml of methylene chloride and cooled to 0 C. While stirring at C C. under a nitro- gen atmosphere, 19.8g (ca 0.192 mole) SCl2 were added dropwise for a period of half hour. The reaction mixture was allowed to warm up to room temperature and stirred fo about ten hours. One-half cf this adduct product was dehvdrohalo genated by rotoevaporation under high vacuum for 5 hours at about 100 C. The adduct analyzed for 1.34 wt. # s and 0.70 wt. % C1. The infrared analysis was consistent with t:at cf a thio-bis (polyisobutenylsuccinic anhydride) adduct. About 80g (ca 0.03 moles) of said adduct were diluted with an equal amount of mineral oil (Solvent i5 Neutral) and heated to 130 C. Then 0.1g of zine acetate dihydrate were added, followed by the addition of 14.5g (c 0.12 moles) of THAM. The reaction mixture was heated slowly to 180 C. and kept at this temperature for 2 hours while sparged with nitrogen. The oil solution was filtered and the filtrate analyzed for 1.27 wt.% nitrogen. An infrared spectrum of this product confirmed the presence of the above-identified tetraoxazoline. EXAMPLE 4 - Dithio-bis-[polyisobutenyl-bis- (5,5-bis-methylol-2-oxazoline) Five hundred grams (ca 0.385 moles) of the poly isobutylene succinic anhydride used in Example 3 were dis solved in 60 ml of methylene chloride and cooled to 0 C. While stirring at ODC. under a nitrogen blanket, 26g (ca 0.192 moles) of sulfur monochloride were added dropwise for a period of half hour. The reaction mixture was allowed to warm up to room temperature and stirred for about ten hours. One-half of this product was rotoevaporatec under ig vacuum at 1000C. for 6 hours. The resulting adduct analyzed for 2.43 wt.E S and 0.65 wt.t C1. Approximately 50g (ca 0.02 moles) of the dithio bis-(pclyisobutenyl succinic anhydride) adduct were mixed Witr 0.1g of zine diacetate and diluted with an equal amount of mineral oil (Solvent 150 Neutral). The oil solution was heated to 1200C. and 9.7g (ca 0.08 mole) of THAM were added. The reaction temperature was slowly raised to 180 C. and kept at thiS temperature for two hours. At the end of the second hour the oil solution was filtered. The filtrate analyzed for 1.14 wt.% nitrogen. The infrared analysis featured strong absorption band at 6.0-6.05 microns con -S-mins the presence of an oxazoline reaction product. ExAMPLE 5 - Reaction product of 1 molar equivalent of thio bis-adduct with 2 molar equivalents of TRAM. About 108g (0.04 mole) of the thio-bis (polyisobutenylsuccinic anhydride) adduct of Example 3 was reacted with 9.7g (0.08 mole) of TRAM under the same conditions as des cribed in Example 3. The product analyzed for 0.63 wt.% nitrogen and 1.35% sulfur. EXAMPLE 6 - Reaction product of 1 molar equivalent of thio bis-adduct with 3 molar equivalents of TRAM. About 108g (0.04 mole) of the adduct of Example 3 was reacted with 14.5g (0.12 mole) of TRAM under the same conditions described in Example 3. The product analyzed for 0.94 wt.% nitrogen and 1.18% sulfur. EXAMPLE 7 - Reaction product of 1 molar equivalent of thio bis-adduct with 1 molar equivalent of TRAM and then reacted with 2 molar equivalents pentaery thritol. About 108g (0.04 mole) of the adduct of Example 3 was reacted with 4.8 (0.04 mole) of THAM under the same conditions described in Example 3. The product analyzed for 0.41 wt.% nitrogen and 1.36% sulfur. About 56g (0.02 mole) of this product dissolved in 54g of Solvent 15G Neutral Base oil, was reacted with 5.4g (C1.04 mole) of pentaerythritol (PE) by heating at 200C for 2 hours while passing nitrogen through the mixture. The reaction product was then purged with nitrogen for 1/2 hour, filtered and recovered. The product analyzed for 0.43 wot.% nitrogen and 1.23 wt.% sulfur; some unreacted PE was rcvereci. EXAMPLE 8 One molar-equivalent of the 1:2 product of E le 5 was reacted with 2 molar equivalents of PE using the procedure of Example 7; the product contained 0.73 wt.%nitro- gen and 1.28 wt.% sulfur. EXAMPlE 9 - Sludge Inhibition Bench (SIB) Test The product of Examples 1, 3 and 4 to 8 and two other dispersant additives were subjected to a Sludge Inhibition Bench (SIB) Test which has been found after a large number of evaluations, to be an excellent test for assessing the dispersing power of lubricating oil dispersant additives. The medium chosen for the Sludge Inhibition Bench Test was a used crankcase mineral lubricating oil composition having ar. original viscosity of about 325 SUS at 1000F. that had been used in a taxicab that was driven generally for short trips only, thereby causing a builds of a high concentration of sludge precursors. The oil that was used contained only a refined base mineral lubricating oil, a viscosity index improver, a pour point depressant and zinc dialkyldithiophosphate antiwear additive. The oil contained no sludge dispersants. A quantity of such used oil was acquired by draining and refilling the taxicab crankcase at 1000-2000 mile intervals. The Sludge Inhibition Bench Test is conducted in the following manner. The aforesaid used crankcase oil, which is milky brown in color, is freed of sludge by centri fuzing for 1/2 hour at about 39,000 gravities (gs.). The resulting clear bright red supernatant oil is then decanted from the insoluble sludge particles thereby separated out. However, the supernatant oil still contains oil-soluble sludge precursors which on heating under the conditions em- ployed by this test will tend to form additional oil-in soluble deposes of sludge. The sludge inhibiting proper- ties of the additives being tested are determined by adding to portions of the supernatant used oil, a small amount, such as 0.5, 1.0 or 1.5 weight percent, on an active ingredient basis, Of the particular additive being tested. Ten grams of each blend being tested is placed in a stainless steel centrifuge tube and is heated at 2800F. for 16 hours in the presence of air. Following the heating, the tube containing the oil being tested is cozies and then cer.: :rifugea for 30 minutes at about 39,000 gs. Any deposits of new sludge that form in this ste are setarated from the oil by decanting the supernatant oil and then carefully washing the sludge deposits with 15 ml. of pentane to remove all remaining oil from the sludge. Then the weight of the new solid sludge that has been formed in the test, in milligrams, is determined by drains the residue and weighing it. The results are reported as milligrams of sludge per 10 grams of oil, thus measuring differences as small as 1 part per 10,000. The less new sludge formed the more effective is the additive as a sludge dispersant. In other words, if the additive is effective, it will hold at least a portion of the new sludge that forms on heating and oxidation, stably suspended in the oil so it does not precipitate down during the centrifuging. VARNISH INHIBITION B2;CE (VIB) TEST In this (VIB) test each test sample consisted of 10 grams of lubricating oil containing 0.07 of a gram of the additive concentrate (50% active) which results in a total of 0.35 wt. % additive present in the test sample. The test oil to which the additive is admixed was 9.93 grams of a commercial lubricating oil obtained from a taxi after 2,000 miles of driving with said lubricating oil. Each ten gram sample was heat soaked overnight at about 1400C. and thereafter centrifuged to remove the sludge. The supernatant fluid of each sample was subjected to heat cycling from about sooc. to room temperature over a period of 3.5 hours at a frequency of about 2 cycles per Iflute. During the heating phase, the gas containing a mixture c about 0.7 volume percent SO2, 1.4 volume percent NO and balance air was bubbled through the test samples and during the cooling phase water vapor was bubbled through the tes samples. At the end of the test iOd, which tensing cycle can be repeated as necessary to determine the me tiros effect of any additive, the wall surfaces of e test flasks in which the samples were contained are visually evaluated. Flasks in which the samples were contained are visually evaluated as to the va=:s i"ibition. The amount of varnish sh imposed on the walls is ratec at values of from 1 to 7 with the higher number being the greater amount of varnish. It has been found that this test correlates with the varnish results obtained as a consequence of carrying out an MS-VC engine test. using the above-described tests, the dispersant action of the oxazoline additives of the Present invention were compared with the dispersing power of one commercial dis persant referred to as PIBSA/TEPA. The PIBSA/TEPA was prepared by reaction of 1 mole of tetraethylene pentamine with about 2 moles of polyisobutenyl succinic anhydride obtained from polyisobutylene of about 1000 number average molecular weight. The PIBSA/TEPA dispersants each used the form of an additive concentrate containing about 50 wt. % PIBSA/TEPA in 50 wt. % mineral lubricating oil. In addition, the oxazoline product of the present invention was also compared with polyisobutenylsuccinic anhydride-bisoxazoline material prepared in accordance with the teachings of DOS 2512201 in the Sludge Inhibition Bench Test. The bisoxazoline designated PIBSA/bis-oxazoline dispersant was prepared via the reaction of 2 molar proportions of tris-(hydroxymethyl) aminomethane with polyisobutenylsuccinic anhydride according to the procedure specified in this patent specification. The test results are given in Table I below. TABLE I VIB Fig Siudgt, log Oil @@ lest Additive wt. %N 0.5 wt. % Rating Blank -- 20.2 11 PIBSA/TEPA 1.5-1.6 9.8 7 pIBS/bis-oxazoline 1.0 11.9 7 Example 1 0.9 2.0 5 3 3 1.27 10.4 6 4 1.14 8.8 7 5 5 0.63 13.8 6 6 ; 0.94 10.4 5 7 7 0.43 14.8 6.5 8 8 0.73 13.2 6 The data of Table I illustrates the superior dispersancy and/or varnish-inhibition activity of the additive products of the invention when compared with commercial dispersants known as PIBSA/TEPA and PIBSA/bis-oxazoline. FX.AMPLE 20 The sulfur-bridged products of the present inven tion and a commercial dispersant additive diluted in mineral oil were evaluated by thermogravietric analysis (TGA) for evidence of thermal stability under oxidative conditions provided by air flow across each sample heated linearly from about 500C. to 4500C. at a rate of 20 /min. Each sample of 5-8 mg (as a Solvent 150 N mineral oil solu tion containing 50 wt.% of an additive) in a platinum planchette was continuously weighed and recorded as the temperature was programmed upwardly at a linear rate to provide a record of sample weight loss versus temperature. The results are found in Table II. TABLE II Temperature at which the indicate.a percentage weight loss occurred Product Additive 10Wt. % 50Wt. % 70Wt. % 90Wt. % Tested OC. OC. OC. OC. Solvent 150 Mineral Oil 230 283 295 310 Ex. 1 275 365 410 440 Ex. 3 270 370 410 440 Ex. 4 275 375 410 440 PIBSA/bis-oxaoline 235 330 400 430 The TCo data shown in Table ri reveal that the compositions of the present invention are significantly more stable towards heat and oxidation than the reference commercial oxazoline dispersant In addition, the TGA data show that the tetraoxazolines of the present invention tend to stabilize the base oil, e.c. S-150N base stock oil, towards thermal oxidative degradation. Thus, the novel structural features built into the present dispersants endow these additives with enhanced thermal stability as well as the ability to inhibit oxida tion of the base stock oil. It is believed that these in hibitor properties can be related in part to the presence of sulfide functionality present in the additive molecules of the present invention.

Claims: WHAT WE CLAIM IS: 1. A process comprising the step of reacting one molar proportion of an acylating reagent of the formula EMI20.1 where Y is sulfur or selenium and R is hydrogen or an alkyl radical containing from 1 to 400 carbons, with from 1 to 4 molar proportions of a 2,2-disubstituted-2-amino-l-alkanol containing a total of 4 to 8 carbon atoms represented by the formula: EMI20.2 wherein X is an alkyl or hydroxyalkyl. group, with at least one of the X substituents being a hydroxy alkyl group of the structure - (CH2)nOH, wherein n is 1 to 3, until the reaction product shows maximal absorption for oxazoline as measured by infrared analysis. 2. The process according to claim 1 wherein said acylating reagent is thio-bis-(polyisobutenylsuccinic anhydride) and said alkanol is tris (hydroxymethyl) amino-methane. 3. The process according to claims 1 or 2 wherein 4 molar proportions of said alkanol are reacted with one molar proportion of said acylating agent. 4. The process according to claims 1 or 2, wherein 2 to 3 molar proportions of said alkanol are reacted with 1 molar proportion of said acylating agent and said reaction product is then reacted with polyamines and/or polyols in an amount sufficient to react with the remaining carboxyl groups of said acylating agent. 5. The process according to claim 4 wherein said alkanol is tris (hydroxymethyl) amino-methane and said polyol is pentaerythritol. 6. A thio-ether reaction product prepared by the reaction of one molar proportion of thio-bis-(acylating reagent) with from 1 to 4 molar proportions of a 2,2-disubstituted-2amino-l-alkanol at a temperature of from 100 to 2400 C. until the reaction is complete by infrared analysis of the reaction product of the reaction showing maximum absorption for oxazoline. 7. A thio-ether reaction product according to claim 6 wherein said alkanol is tris (hydroxymethyl) amino-methane. 8. A thio-ether reaction product according to claim 6 or 7 wherein said alkanol is used in an amount ranging from 1 to 3 molar proportions and said reaction product is thereafter reacted with polyamines and/or polyols in an amount sufficient to react with the remaining carboxyl groups of said acylating reagent. 9. A compound represented by the formula: EMI22.1 wherein R is selected from the group consisting of hydrogen and alkyl radicals containing from 1 to 400 carbons, X is selected from the group consisting of an alkyl or hydroxy alkyl group and at least one of the X substituents being a hydroxy alkyl group of the structure -(CX2)nOH where n is 1 to 3, and Y is selected from the group consisting of -S-, -S-S-, ----S=O, # SO2, -Se- and -S-(CH2)@-S- wherein z is a number from 2 to 10. 10. A compound according to claim 9 wherein both of said X substituents are a hydroxy alkyl group of the structure -(CH2)nOH, n is 1 and Y is selected from -S- and -S-S- whereby a thio-bis (hydrocarbon-bisoxazoline) is realized. 11. Dithio-bis-[polyisobutenyl-bis-(5,5,-bis methylol-2-oxazoline) ] . 12. Thi-bis-[polyisobutenyl-bis-(5,5,-bis methylol-2-oxazoline) 1. 13. A composition comprising an oleaginous material of the class consisting of fuels and lubricants and at least a corrosion-inhibiting amount of a compound represented by rhe EMI23.1 wherein R is selected from the group consisting of hydrogen and alkyl radicals containing from 1 to 400 carbons, X is selected from the group consisting of an alkyl or hydroxy alkyl group and at least one of the X substituents being a hydroxy alkyl group of the structure -(CH2)nOH where n is 1 to 3, and Y is selected from the group consisting of -S-, -S-S-, '-S=O, - SO2, -Seand -S-(CH2)z-S- wherein z is a number from 2 to 10. 14. A composition according to claim 13 wherein said oleaginous material is a lubricating mineral oil containing 0.01 to 20 wt. % of said compound. 15. A composition according to claim 13 wherein said oleaginous material is a lubricating mineral oil containing from 20-90 wt. % of said compound. 16. A composition according to claim 13 wherein said oleaginous material is gasoline and said compound is present in amount ranging from 4-20 parts per million based on the total weight of said composition.

Inventors: BROIS, STANLEY JAMES, GUTIERREZ, ANTONIO
Applicants: EXXON RESEARCH AND ENGINEERING COMPANY
Application year: 1980
Main classification: C07D263
IPC codes: C10L1, C07D263, C07D307, C10M135