3,281,355 United States Patent Office Patented Oct. 25, 1966 2 MoC)Br2, MoaOCls, MoOCls, MoOF. It is also pos 3,281,355 sible to employ aqueous sulfuric acid solutions of MoC3, STABLE COLLOIDAL DESPERSONS OF or H2MoC) or molybdenum blue. Other suitable start MOLYBDENUM SULFIDE ing materials include solutions of molybdenum naph Elmer B. Cyphers, Cranford, and Max W. Hill, Westfield, N.J., assignors to Esso Research and Engineering Com thenates or sulfonates in one or more of the lower alco pany, a corporation of Delaware hols. By lower alcohol is meant a C to Caliphatic al No Drawing. Filed Nov. 15, 1963, Ser. No. 323,887 cohol, i.e., methanol, ethanol, isopropyl alcohol or butyl 14 Claims. (Cl. 252-18) alcohol. The formation of the molybdenum sulfide can be car The present application is a continuation-in-part of ap O ried out in the presence of the detergent additive per se. plication Serial No. 99,688, filed March 31, 1961, and It is usually more convenient, however, to carry out the abandoned subsequent to the filing of the present appli formation in an oil concentrate of the detergent additive. cation. These concentrates usually contain about 10 to 80 wt. This invention relates to the preparation of composi percent of the detergent additive, with the remainder be tions containing stably dispersed molybdenum sulfide of 5 ing lubricating oil. colloidal particle size and to the use of such compositions The lubricating oil may be either a mineral oil or a in lubricating oil formulations. Particularly, the inven synthetic oil. Examples of synthetic oils include syn tion relates to the formation of molybdenum sulfide in thetic hydrocarbon oils, polysilicones, polyglycols, dibasic situ by the reaction of a molybdenum-containing com acid esters such as di-2-ethyl hexyl sebacate, carbonate pound with a sulfur-containing compound in the presence 20 esters, glycol esters such as C3 oxo acid diesters of tetra of a protective colloid or a dispersant-detergent. ethylene glycol, and complex esters, as for example the Molybdenum sulfide has been recognized as an excel complex ester formed by the reaction of 1 mole of sebacic lent lubricating material because of its outstanding reduc acid with 2 moles of tetraethylene glycol and 2 moles tion of wear and friction. This material has been widely of 2-ethyl hexanoic acid. The mineral lubricating oils used in the formulation of solid grease compositions. 25 may be of any suitable type including those derived from However, its insolubility in lubricating oil and its black the ordinary paraffinic, naphthenic, asphaltic or mixed color have militated against its use in liquid lubricant base mineral crude oils by suitable refining methods. compositions such as crankcase oils for internal combus The detergent additives which are operable as dis tion engines. Many attempts to incorporate molybdenum persants for the present invention include the petroleum sulfide into fluid oil have been made by grinding the 30 sulfonates, synthetic alkyl aryl sulfonates, various alkyl molybdenum sulfide to an exceedingly fine particle size phenates, alkyl phenate sulfides, phosphosulfurized olefin and then dispersing it in oil. Such dispersions still have polymers, and various combinations of these additives. a dark color and the solid particles tend to settle out of Following are specific descriptions of several of the above the oil during storage. types of detergent additives. It has now been found that by preparing molybdenum 35 Petroleum sulfonates generally used as lubricating oil Sulfide in situ in the presence of certain protective col detergents are the oil-soluble alkaline earth metal salts loidal materials it is possible to obtain stable dispersions of high molecular weight sulfonic acids. These sulfonic which avoid the black color normally associated with acids are produced by the treatment of petroleum oils of molybdenum sulfide. While the molybdenum sulfide is the lubricating oil range with fuming sulfuric acid and preferably prepared by the reaction of a molybdenum salt 40 generally have molecular weights of about 300 to 700. and hydrogen sulfide, it is within the scope of the in Petroleum sulfonates are well known in the art and have vention to employ other sources of the sulfide ion such been described in numerous patents, e.g., U.S. 2,467,176. as ammonium hydrosulfide, or ammonium polysulfide, Detergent sulfonates can also be derived synthetically or the corresponding alkali metal derivatives, e.g. sodium from relatively pure alkyl aryl sulfonic acids having from or potassium hydrosulfide or polysulfide. The protective 45 about 10 to 33 carbon atoms per molecule. For exam colloidal materials are those materials which are known ple, sulfonated products of alkylated aromatics such as in the lubricating art as detergent additives. Since such benzene, toluene, Xylene, and naphthalene, alkylated with detergent additives are normally added to automotive olefins or olefin polymers of the type of polypropylene, crankcase oils they can now be made to serve the addi polyisobutylene, etc., can be used. tional function of stably suspending the molybdenum sul 50 Specific examples of the above two types of sulfonates fide. The resulting compositions containing molybdenum include calcium petroleum sulfonate of about 880 molec Sulfide show a marked tendency in reducing wear and ular weight, barium petroleum sulfonate of about 980 friction as will be later demonstrated. molecular weight, calcium C alkyl benzene sulfonate, Stated more explicitly the process of this invention is barium C alkyl benzene sulfonate and calcium C alkyl conducted by reacting a water-soluble or a lower-alcohol 55 benzene sulfonate; wherein said C alkyl group is derived Soluble salt of a compound of molybdenum in which from diisobutylene; said C alkyl group is obtained from compound the valence of molybdenum is at least four, tripropylene and said C alkyl group is obtained from with a reagent effective to furnish sulfide ions and there tetraisobutylene. by form molybdenum sulfide, the reaction being con The above sulfonates may be either neutral sulfonates, ducted in the presence of a lubricating oil detergent addi 60 i.e. where the sulfonic acid is neutralized with an equal tive that is capable of stably suspending molybdenum sul mole equivalent amount of metal base, or the sulfonates fide in the lubricating oil. may be of the so-called "high alkalinity' type. In the lat Particularly useful molybdenum salts for forming the ter case, additional metal base, in excess of that required for simple neutralization, is reacted with the sulfonic sulfide are those of the formula: XMoO, wherein X rep 65 acid to form an alkaline product which can then be resents a metal or an ammonium radical, and n is either blown with carbon dioxide to reduce its alkalinity and 1 or 2, depending upon the valence of X. Specific exam form a substantially neutral final product. The term sul ples of such molybdates include ammonium molybdate fonate as used herein and in the appended claims in and alkali metal molybdates such as those of sodium or cludes both neutral sulfonates and so-called high alkalinity potassium. 70 (or high metal content) sulfonates. Other molybdenum salts that may be used in aqueous Metal salts of alkyl phenols and of alkyl phenol sulfides solution include MoCl4, MoBra, MoCaCl2, Mo.OCl, are also well known in the art. Metal salts of alky1 3,281,355 3 4 phenols having straight chain or branched chain alkyl . . The molybdenum-sulfide-containing compositions of groups of from 5 to 20 carbon atoms are usually preferred, the invention are prepared by any number of methods, and the metal used to form the phenate is preferably an several of which follow: alkaline earth metal, e.g., calcium, barium, strontium, or A molybdenum salt such as ammonium molybdate is magnesium, although other salts such as those of alumi dissolved in water and the resulting solution is slowly num, sodium, cobalt, lead, chromium or tin are some added to heated detergent while bubbling hydrogen Sul times used. A specific example is the barium salt of the fide through the detergent. The temperature of the de alkylation product of phenol with tripropylene. Metal tergent during this addition is maintained in the range salts of the corresponding alkyl phenol sulfides may also of about 250° to 600 F., preferably 275 to 425 F. be used. The latter are the thioethers and polysulfides of O Alternatively, all the aqueous solution of molybdenum alkyl phenols, i.e. compounds in which the alkyl groups salt is first added to the hot detergent, and then hydrogen are joined by one or more divalent sulfur atoms. The sulfide is bubbled through the mixture. In either case, alkyl phenols can be converted to phenol sulfides by re molybdenum sulfide is formed in situ and sufficient heat action with sulfur dichloride. If sulfur monochloride is is applied to boil off the water and to help promote the used, the resulting products are primarily alkyl phenol 5 reaction between the hydrogen sulfide and the salt. For disulfides. Specific examples of the phenate sulfides in purposes of economy, it is preferred that the water solu clude barium tertiary octyl phenol sulfide, calcium tertiary tion of the molybdenum salt be saturated so as to min octyl phenol sulfide, barium-calcium nonyl phenol Sul imize the amount of water to be later evaporated. Such fide, barium tertiary amyl phenol sulfide, calcium dodecyl a saturated solution will usually contain about 15 wt. per phenol sulfide, and barium nonyl phenol sulfide. High 20 cent of the salt in the use of ammonium molybdate. It alkalinity (i.e. high metal content) phenates and phenate is more preferred to add a small amount of a volatile acid sulfides are also included in the above description. These such as hydrochloric acid or acetic acid, or ammonium materials are prepared by reacting the phenol sulfide with hydroxide in order to increase the solubility of the molyb an excess of metal base and then neutralizing the basic denum salt in water. In this way, saturated solutions con product, generally by CO2 blowing. 25 taining as much as about 20% of the molybdenum salt The phosphosulfurized olefin materials are also well can be obtained. As another alternate procedure, the known in the art. These materials are prepared by react aqueous solution of molybdenum salt can be added to the ing an olefin or an olefin polymer with a sulfide of phos detergent at room temperature and hydrogen sulfide phorus, preferably P2S5. The olefin polymers have bubbled through the mixture. Staudinger molecular weights in the range of from about 30 Since many lubricating oil detergent additives are also 500 to about 200,000 and contain from 2 to 6 carbon emulsifiers, an emulsion may be formed between the aque atoms per olefin monomer. Polymers of ethylene, pro ous solution and the detergent or the oil concentrate con pylene or butylene may be used, for example. In gen taining the detergent. This emulsion results in intimate eral, the phosphosulfurized polyolefin is prepared by re contacting of the molybdenum sulfide particles with a pro acting the polyolefin with from 5 to 30 weight percent of 35 tective coating of detergent additive as soon as the molyb a sulfide of phosphorus, and preferably with 10 to 20 denum sulfide particles are formed. When the reaction weight percent of phosphorus pentasulfide. The phospho is completed and agitation discontinued, then various sulfurization reaction is conducted under anhydrous con emulsion breakers such as Ci to C alcohol or sodium ditions at temperatures in the range of 150 to about chloride can be added to the reaction mixture. When the 600 F. for from about 4 to 15 hours. It is advisable to 40 emulsion breaks, the water layer can then be decanted and treat or blow the phosphosulfurized product with an inert the remainder of the material can be heated to dryness. gas such as nitrogen for a period of from 10 minutes to Or the use of emulsion breakers can be dispensed with 2 hours to aid in reducing hydrogen sulfide evolution and and all of the water can be evaporated by simply heating its corresponding odor. The preparation of phosphosul the reaction product until a dry product is obtained. furized hydrocarbons and the use of catalysts in the phos 45 In any case, it will be generally preferred to filter the phosulfurization reaction are more fully described in U.S. final material to remove any molybdenum sulfide which Patent 2,875,188. may have precipitated. Thus, in practice, it has been Other detergent additives useful in this invention in found difficult to disperse more than about 2.0 wt. per clude the reaction products of phosphosulfurized hydro cent based on the total final reaction product, of molyb carbons with alkaline earth metal oxides or hydroxides 50 denum sulfide. Amounts of molybdenum sulfide in ex which can be prepared by first treating a hydrocarbon with cess of this will generally precipitate from solution, but the phosphorus sulfide and then reacting the product with are easily removed by simple filtration. an alkaline earth hydroxide or oxide, for example, barium In an alternative procedure, an organic molybdenum hydroxide, preferably in the presence of carbon dioxide. Salt such as molybdenum naphthenate is dissolved in The dispersants of this invention may also include high 55 alcohol and added slowly to the detergent at room tem molecular weight polymeric dispersants made with one perature while stirring and bubbling hydrogen sulfide or more polar monomers, such as vinyl acetate, vinyl pyr through the mixture, followed by heating to remove the rolidone, methacrylates, fumarates and maleates. These alcohol while continuing the addition of hydrogen sulfide. dispersants have molecular weights in the range of about After all the alcohol is removed, the mixture is filtered. 500 to 50,000. One example is a copolymer of 65 to 85 60 In still another embodiment of this invention, sepa weight percent of mixed Co-C12 fumarates, 10 to 20 weight rate aqueous solutions of ammonium molybdate and am percent of vinyl acetate, and 5 to 15 weight percent of monium polysulfide are simultaneously added dropwise N-vinyl pyrrollidone. Another example is the copolymer to the detergent while stirring vigorously at room tem derived by reaction of mixed tallow fumarates and C perature. The aqueous layer is then separated by add oxo fumarates, averaging about 420 molecular weight, 65 ing sufficient alcohol and heptane to produce two dis with vinyl acetate in a 3 to 1 acetate-fumarate ratio, and Crete layers, separating the layers, discarding the aqueous 3 weight percent of maleic anhydride, followed by subse layer, and evaporating the solvent from the detergent quent removal of excess vinyl acetate. By tallow fuma mixture, which is finally filtered. rates is meant the esters of fumaric acid and the alcohols While the above procedures represent preferred meth derived by hydrogenation of tallow. The latter are prin 70 ods of forming the molybdenum sulfide, actually it is cipally C16 and Cia alcohols with minor amounts of C2, only essential that the molybdenum sulfide be formed C14 and Cao alcohols. Ca oxo alcohols are prepared by in the presnce of the detergent additive and this may reaction of carbon monoxide and hydrogen on mixed be accomplished in any manner. - Ca-C, olefins followed by hydrogenation of the resulting The final oil compositions of the invention will com aldehydes. - 75 prise a major proportion of lubricating oil and about 3,281,355 5 6 0.001 to 1.5 weight percent of finely dispersed molyb maceous earth in a Buchner funnel to remove any pre denum sulfide and about 0.1 to 20 weight percent of a cipitated particles of molybdenum sulfide. lubricating oil detergent additive. Preferred proportions The filtered product was a clear, brown liquid which are 0.005 to 0.5 wt. percent of molybdenum sulfide and remained clear and stable indefinitely at room tempera 2 to 10 wt. percent detergent. ture and analyzed about 1.1 wt. percent molybdenum Various conventional lubricating oil additives may metal. A 5% blend of the filtered product in white oil also be incorporated in the composition of the inven showed a nephelometer reading of 18, which was the tion to form finished motor oil lubricants or other oil same as the original unreacted Detergent Concentrate compositions such as turbine oils, hydraulic fluids, trans A, and was perfectly clear to the naked eye. mission fluids, industrial oils, or the like. For example, O additives in the amounts of 0.1 to 10 weight percent EXAMPLE 2. may be added, such as pour point depressants, e.g. wax A base stock blend was prepared from: alkylated naphthalene or copolymers of vinyl acetate Parts and alkyl fumarates, V.I. improvers such as polymeth Low cold test coastal distillate of 76 SUS/100 F. acrylates or polyisobutylene, anti-oxidants such as 2,6 5 and 63 V.I. ------46.9 ditertiary butyl para cresol, phenyl-alpha-naphthylamine, Mid-Continent neutra-150 SUS/100 F. and hydroquinone monoalkyl ether, or bisphenols, dyes, etc. 100 V.I. ------46.9 The invention will be further understood by the fol Additive B ------5.0 lowing examples: Acryloid 710 ------1.0 EXAMPLE 1. 20 Additive C ------0.2 Part A.-Detergent Concentrate A, used in this ex The inspections on this base stock blend are: ample consisted of about 70 wt. percent of a detergent Gravity API ------30.8 additive and about 30 wt. percent mineral lubricating SUS.VIS/100 F. ------1813 oil. The detergent additive itself was prepared by heat 25 SUS.VIS/210 F. ------48.6 ing a mixture consisting of about 40 wt. percent of a Pour, F. ------35 phosphosulfurized polyisobutylene, 30 wt. percent of an Cloud, F. ------6 oil concentrate of a high barium content tertiary octyl Flash COC, F. ------360 phenol sulfide and about 30 wt. percent of an oil solu Fire COC, F. ------385 tion containing 60 wt. percent of a high barium content 30 synthetic sulfonate. Additive B was a 33 wt. percent solution of polyisobu The phosphosulfurized polyisobutylene was prepared tylene of about 10,000 molecular weight in 67 wt. per by reacting polyisobutylene of about 1100 molecular cent of a solvent neutral mineral oil of 150 SUS. viscosity weight with 15 wt. percent based on the weight of at 100 F. The Acryloid 710 was a polymethacrylate polyisobutylene, of PSs at about 425 F. for about 8 35 viscosity index improver. hours under a nitrogen atmosphere. The oil concen Additive C consisted of 37% volume percent of a trate of the barium tertiary octyl phenol sulfide con copolymer of Lorol B fumarate and vinyl acetate, 12.5 sisted of about 43 wt. percent of the said sulfide and volume percent of the condensation product of chlorinated about 57 wt. percent of a mineral lubricating oil. The wax and naphthalene and 50 volume percent of a neu barium tertiary octyl phenol sulfide was of the high 40 tral mineral oil of 45 SUS. at 100 F. The copolymer alkalinity type having an alkaline neutralization number is primarily a viscosity index improver while the conden of about 90 and contained about 12 wt. percent barium. sation product is a pour depressant. The high barium sulfonate had a barium content of 5.0 wt. percent of the filtered molybdenum sulfide pro about 14 wt. percent based on the weight of the duct of Example 1 was added by simply mixing to 95.0 sulfonate. The sulfonic acid portion of the sulfonate 45 wt. percent of the above described base stock blend. The was prepared by alkylating benzene with polypropylene, resulting final product represents a fully formulated said sulfonic acid portion having an average molecular crankcase motor oil. This final product containing the weight of about 440 of which 75 wt. percent of the molybdenum sulfide, and also the base stock per se, i.e. sulfonic acid radicals had a molecular weight greater without the molybdenum sulfide, were tested in a Kine than 400. This sulfonate was prepared by reacting neu 50 matic Oiliness Test Machine (KOTM). This machine tral barium sulfonate with additional barium hydroxide and test are completely described in U.S. Patent No. followed by neutralizing by bubbling carbon dioxide 2,909,056. The KOTM machine comprises 3 steel fric through the sulfonate. tion buttons contacting by an annular track, with means The mixture of phosphosulfurized polyisobutylene, for applying weights to the friction buttons. Both the barium tertiary octyl phenol sulfide, and barium sulfo 55 track and buttons are immersed in a bath of the lubricant nate was heated at 350 F. for about 12 hours and to be tested. As the track rotates, it exerts a drag upon filtered to produce the Detergent Concentrate A. Part B.-A dispersion of molybdenum sulfide and the friction buttons, which drag can be measured. The detergent additive was prepared as follows: A substan results of this KOTM test, as well as of other well-known tially saturated solution was prepared by dissolving 160 60 conventional load-carrying tests are Summarized in grams of ammonium molybdate having the formula: Table I. (NH4)Mo.O. 4H2O in 500 grams of water and 90 TABLE grams of concentrated ammonium hydroxide. Into an open stainless steel pot was placed 3200 grams of Deter Base 5.0%. MoS 65 Laboratory Tests Units Stock Sol in 95% gent Concentrate A. Detrgent Concentrate A was stirred Base Stock and heated under a hood to a temperature of about 325 F. The aforementioned aqueous solution of the KOTM (Steel Buttons and ------Poor Very Good Track). ammonium molybdate was slowly added to the hot de 4 Ball Wear Test.------IIIl------0.49 0.25 tergent concentrate over a period of about 160 minutes. 4 Bai E. P. Test: The mixture was further heated at 325 F., after the 70 Seizure Load------Kg------7. 00 water had evaporated, and then hydrogen Sulfide was Weld Load------Kg------2 200 SAFalo Machine, 14,611 Slip Scale lbs. <20 55 added, while stirring the mixture over a period of about Almen Test, Gradual Loading-- 2 lb. wits.------1. 4 hours. Excess hydrogen sulfide was thus utilized in Tinken OK Load------Libs------5 order to insure complete reaction of all molybdate. Falex Machine------Libs------1,250 The reaction mass was then filtered hot through diato 75

3,281,355 7 8 EXAMPLE 3 calcium salt of monododecyl benzene sulfonic acid in 60 A lubricating oil composition was prepared by mixing weight percent mineral lubricating oil. 5 wt. percent - 4.5 wt. percent of the filtered molybdenum sulfide product of the resulting filtered product can then be added to 95 of Example 1 with 95.5 wt. percent of a base stock wt. percent of a mineral lubricating oil having a viscosity containing mineral lubricating oil, a polymeric viscosity of 55 SUS. at 210 F. to thereby improve the load index improver, a pour point depressant and a small carrying and anti-wear properties of said lubricating oil. amount of a zinc dialkyl dithiophosphate as antioxidant. While the specific examples of detergents shown rep The resulting composition was tested in the L-1 Cater resent preferred detergent materials, any detergent which pillar Test. For comparison purposes, 4.5 wt. percent of will stably Suspend the molybdenum sulfide in oil can Detergent Concentrate A (previously described) was O be used. added to 95.5 wt. percent of the same base stock, and EXAMPLE 8 the resulting comparison composition was also tested A solution of 12.5 grams of 85% molybdic oxide in in the well-known L-1 Caterpillar Test. The results ob 300 grams of water was prepared by adding NH4OH to tained are summarized in Table II. 5 clear the solution. The solution was then acidified with ABLE II H2SOA and 9 grams excess of H2SO4 added. Then, 500 grams of phosphosulfurized polyisobutylene diluted with With Without, L-1 Caterpillar Test Molybdenum Molybdenum 200 grams of heptane to reduce its viscosity was stirred Sufide Sulfide in a 2-liter beaker at room temperature and treated with 20 H2S by bubbling the gas through it continuously while, 20ours: at the same time, adding the above molybdic acid solu Ring Zone, Demerit------0.09 0.16 Lower Ring Zone Area, Demerit.-----. 0.01 0.01 tion slowly over a period of 2 hours with vigorous stir Top Groove Fill, Percent------1.0 .5 ring. The H2S treatment was continued one hour after 240 Hours: all the solution had been added. Ring Zone, Demerit------0.28 0.56 Lower Ring Zone Area, Demerit O, O. 0.02 25 The mixture was transferred to a 4-liter separatory Top Groove Fill, Percent.----- 8 16 funnel and enough heptane and isopropyl alcohol added to produce two separate layers. The aqueous layer, con As seen by the table, the molybdenum sulfide con taining alcohol and some precipitated molybdenum sul taining composition was superior in cleanliness as meas fide was discarded. The upper layer was filtered and ured by ring zone, lower ring zone area and top groove 30 the heptane stripped off by nitrogen blowing on a steam fill demerits, when compared to the exact same composi bath. The product was clear and stable and showed tion, but containing no molybdenum sulfide. 0.53% Mo by analysis. The phosphosulfurized polyiso butylene employed in this example was prepared as de EXAMPLE 4 scribed in U.S. Patent 2,969,324, column 10, 1ines 12-26 A molybdenum sulfide sol was prepared in a similar 35 (Intermediate 3). manner to that described in Example 1, but instead of EXAMPLE 9 using Detergent Concentrate A, an additive concentrate was used which consisted of about 40 wt. percent of Part A-Preparation of molybdenum blue high alkalinity barium-calcium nonyl phenol sulfide in After 50 grams of 85% molybdic oxide was stirred 60 wt. percent mineral oil. The resulting product, after 40 into 500 grams of water, 50 grams of conceneration being filtered, analyzed 0.68% molybdenum. NH4OH solution was added to produce a clear aqueous EXAMPLE 5 Solution. To this was added 150 grams of concentra tion H2SO4, slowly with stirring. After cooling to about A molybdenum sulfide sol was prepared in a manner 100 F., 3 grams of aluminum foil was added and stir similar to that described in Example 1, except that in 45 ring continued overnight. A light blue color developed. place of Detergent Concentrate A, the detergent concen The following morning the solution was heated to 130° trate consisted of about 40 wt. percent of an overbased F. and maintained between 100 and 130 F. for about barium salt of an alkyl phenol sulfide in about 60 wt. 4 hours. A deep blue color developed, indicating the percent mineral lubricating oil. The resulting product, formation of "molybdenum blue,” a colloidal aqueous after being filtered, analyzed about 0.31 wt. percent 50 dispersion reported in the literature to have the composi molybdenum. tion MoC2.5-3.0.XH2O. Stirring was continued for 40 EXAMPLE 6 hours and the solution which contained some blue pre A molybdenum sulfide sol was prepared in a manner cipitate, was then filtered. similar to that described in Example 1, except that in The filtrate was a clear deep blue solution (692 gms.), place of Detergent Concentrate A, the detergent con 55 The filter cake, which was also deep blue, was extracted centrate consisted of 60 wt. percent high-magnesium With additional water resulting in substantially complete content sulfonate and 40 wt. percent mineral oil. The recovery of the blue cake in the form of a deep blue sulfonic acid portion averaged about 440 molecular aqueous solution (154 grams). weight and was prepared by alkylating benzene with Part B-Preparation of molybdenum sulfide sol polypropylene. The resulting product analyzed about 60 0.73 wt. percent molybdenum. 400 grams of Detergent A was placed into a 2,000 ml. The preceding examples are illustrative of the invention, beaker and stirred continuously at room temperature. and other known detergent additives for motor oil can H2S gas was bubbled through the mixture while the larger be utilized in forming the molybdenum sulfide protective portion of the molybdenum blue solution from part A sol. For example, Example 1 can be repeated but using 65 was added slowly over a period of 70 minutes. The HS a PS5-treated polyisobutylene of the type previously de gas addition was continued for one hour longer. Then the scribed as the suspending detergent in place of Detergent Smaller portion of the molybdenum blue solution was Concentrate A. added slowly over a period of 35 minutes and HS flow 70 was again continued for one more hour. EXAMPLE 7 After standing about 40 hours there was no separation As still another example of the invention, Example 1 of water and detergent. The mixture was therefore trans is exactly repeated but in place of the 3200 grams of ferred to a 6-liter separatory funnel and heptane, iso Detergent Concentrate A, 3200 grams of a concentrate propyl alcohol, and water were added until two distinct is used consisting of 40 weight percent of the neutral 75 layers formed.

3,281,355 O This method of emulsion breaking is well known to What is claimed is: - those skilled in the art. The amount of each ingredient 1. A method for preparing a stable dispersion of to be added is guided by the appearance of the emulsion. molybdenum sulfide which comprises the steps of: pre For example, if the emulsion is white, alcohol is added paring a mixture of a lubricating oil detergent additive, until it becomes relatively clear. Then heptane and water capable of stably suspending molybdenum sulfide in lubri are added alternately to increase the difference in density cating oil, and a solution of a molybdenum compound of the layers. If whiteness again develops, more alcohol dissolved in a solvent selected from the group consisting is added and the steps are repeated. While no exact of water and C to C4 aliphatic alcohols, said molybdenum record of individual additions was kept, it is estimated compound being characterized by having a molybdenum that the final mixture contained in the range of 10-15% 0. atom with a valence of at least four and by being soluble of detergent, 25-35% of heptane, 10-20% of isopropyl in a solvent selected from the group consisting of water alcohol, and 35-50% of water. and C1 to C4 aliphatic alcohols; contacting said mixture After the two distinct layers had formed, the aqueous with a reagent effective to furnish sulfide ions, whereby layer containing most of the alcohol and some precipitated finely dispersed molybdenum sulfide is formed; and re molybdenum sulfide was discarded. The heptane solu 5 moving said solvent from the reaction mixture. tion, containing the detergent with colloidally dispersed 2. A method according to claim 1 wherein said reac molybdenum sulfide, was filtered and the heptane stripped tion mixture is heated to facilitate solvent removal and off by blowing with nitrogen on a steam bath, followed to promote the formation of molybdenum sulfide. by heating in a vacuum oven. The product was clear and 3. A method according to claim 1 wherein said molyb stable and showed 0.85% Mo by analysis. 20 denum compound is a molybdate having the general formula: EXAMPLE 10 X (MoO4) A sol of molybdenum sulfide in detergent additive is wherein X is a member selected from the group consisting prepared as follows: of ammonium radicals and metal, and wherein n is a A solution of 200 grams of molybdenum tetrabromide, 25 number from 1 to 2. MoBI, in 1000 grams of water is slowly added to 3200 4. A method according to claim 1 wherein said reagent grams of Detergent Concentrate A with constant stirring comprises hydrogen sulfide. - at a temperature of 325 F. as in Example 1. The result 5. A method according to claim 1 wherein said reagent ing product is then treated with an excess of hydrogen comprises a sulfide from the class consisting of alkali sulfide and filtered to produce a clear, stable sol of 30 metal hydrosulfides, alkali metal polysulfides, ammonium molybdenum sulfide. hydrosulfide and ammonium polysulfide. EXAMPLE 11 6. A method as defined by claim 1 wherein said lubri After 3,200 grams of Detergent Concentrate A has cating oil detergent additive is an alkaline earth metal been stirred and heated to 350 F. and saturated with 35 sulfonate. H2S gas, an aqueous solution made by dissolving 100 7. A method as defined by claim 1 wherein said lubri grams of molybdenum dioxydichloride in 1,000 grams cating oil detergent additive is a metal salt of an alkyl of water is added slowly, while simultaneously adding phenol sulfide. HS to maintain an excess of H2S. The resulting prod 8. A method as defined by claim 1 wherein said lubri uct is filtered to produce a clear, stable sol of molybdenum 40 cating oil detergent additive is a phosphosulfurized poly Sulfide. isobutylene. EXAMPLE 12 9. A method of preparing a stable dispersion of molyb Two mois of ammonium hydrosulfide are dissolved in denum sulfide in a lubricating oil which comprises mix sufficient water to make 250 ml. of solution and placed ing an aqueous solution of water-soluble molybate with in a graduated dropping funnel A. Then, 0.4 mol of 45 a lubricating oil containing a lubricating oil detergent ad ammonium molybdate and 20 ml. of concentrated am ditive capable of stably dispersing molybdenum sulfide in monium hydroxide are dissolved in sufficient water to said lubricating oil, passing hydrogen sulfide through the make 250 ml. of solution and placed in a graduated drop resulting mixture to form molybdenum sulfide, and re ping funnel B. Then 500 grams of Detergent Concen moving water to form a dry product. trate A are placed in a 3-liter beaker equipped with an 50 10. A stable lubricating oil composition comprising a efficient stirrer. major amount of a mineral lubricating oil, about 0.005 to While stirring Detergent Concentrate A, the contents 0.5 wt. percent of molybdenum sulfide in the form of a of dropping funnels A and B are added dropwise over a stable dispersion and about 2 to 10 wt. percent of a lubri period of 2 to 3 hours, taking care that approximately cating detergent additive capable of stably suspending equal amounts of each solution are added in any given 55 molybdenum sulfide in said lubricating oil, said molyb time interval. After all of the aqueous solutions are denum sulfide dispersion having been prepared by con added, stirring is continued for one hour. verting a soluble molybdenum compound to molybdenum The mixture is then transferred to a 6-liter separatory Sulfide in the presence of said detergent additive, said solu funnel and treated as in Example 9 to break the emulsion, ble molybdenum compound being selected from the group separate the water, evaporate the solvent and remove any 60 consisting of water-soluble and lower-alcohol-soluble precipitate by filtration. molybdenum compounds in which molybdenum has a val As demonstrated above, concentrates containing 0.1 ence of at least four. to as much as about 2.0 wt. percent of molybdenum sul 11. A stable lubricating oil composition comprising fide with about 5 to 80 wt. percent detergent additive (ac from about 0.1 to 80 wt. percent of a lubricating oil de tive ingredient basis) in oil are readily prepared by the 65 tergent additive capable of stably suspending molybdenum techniques of this invention. These concentrates can Sulfide in a lubricating oil, from about 0.001 to 1.5 wt. then be added to lubricating oil compositions to give percent of molybdenum sulfide in the form of a stable finished lubricants containing 0.001 to 1.5, preferably dispersion, and the remainder a lubricating oil, said 0.005 to 0.5 wt. percent of the molybdenum sulfide. molybdenum sulfide dispersion having been prepared by It is to be understood that the examples presented herein 70 converting a soluble molybdenum compound to molyb are intended to be merely illustrative of the invention and denum sulfide in the presence of said detergent additive, not as limiting it in any manner; nor is the invention to said soluble molybdenum compound being selected from be limited by any theory regarding its operability. The the group consisting of water-soluble and lower-alcohol scope of the invention is to be determined by the appended soluble molybdenum compounds in which molybdenum claims. 75 has a valence of at least four. 3,281,355 1. 12 12. A stable lubricating oil additive concentrate com in a lubricating oil and from about 0.1 to about 2.0 wt. prising from about 10 to 80 wt. percent of a lubricating percent of molybdenum sulfide in the form of a stable oil detergent additive capable of stably suspending mo dispersion that has been prepared by converting a soluble lybdenum sulfide in a lubricating oil, from about 0.1 to molybdenum compound to molybdenum sulfide in the 2.0 wt. percent of molybdenum sulfide in the form of a presence of said detergent additive, said soluble molyb stable dispersion, and the remainder a lubricating oil, said denum compound being selected from the group consist molybdenum sulfide dispersion having been prepared by ing of water-soluble and lower-alcohol-soluble molybde converting a soluble molybdenum compound to molyb num compounds in which molybdenum has a valence of denum sulfide in the presence of said detergent additive, at least four. said soluble molybdenum compound being selected from O the group consisting of water-soluble and lower-alcohol References Cited by the Examiner soluble molybdenum compounds in which molybdenum UNITED STATES PATENTS has a valence of at least four. 13. A stable lubricating oil composition comprising 2,609,342 9/1952 White et al. ------252-25 from about 0.1 to 80 wt. percent of a lubricating oil de 15 2,619,458 11/1952 McBride ------252-25 tergent additive capable of stably suspending molyb 2,781,314 2/1957 Wasson ------252-25 denum sulfide in a lubricating oil, from about 0.001 to 1.5 2,956,018 10/1960 Carlyle et al. ------252-18 wt. percent of molybdenum sulfide in the form of a stable 3,057,896 10/1962 Schlicht et al. ------252-18 dispersion, and the remainder a lubricating oil, said mo FOREIGN PATENTS lybdenum sulfide dispersion having been prepared by 20 converting a water-soluble molybdate salt to molybdenum 570,814 2/1959 Canada. sulfide in the presence of said detergent additive. 574,161 4/1959 Canada. 14. A stable dispersion of molybdenum sulfide com prising a major proportion of a lubricating oil detergent DANIEL E. WYMAN, Primary Examiner. additive capable of stably suspending molybdenum sulfide 25 L. G. XLARHOS, Assistant Examiner.