Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M159/00—Lubricating compositions characterised by the additive being of unknown or incompletely defined constitution
  • C10M159/12—Reaction products
  • C10M159/20—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products
  • C10M159/22—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products containing phenol radicals

Definitions

• This invention relates to compounds useful as antioxidants and detergents in lubricating oils and methods for their manufacture and, more specifically, to overbased sulfurized phenates.
• Lubricating oils tend to deteriorate under normal operating conditions encountered in present-day diesel and automotive engines. Sludge, lacquer and residence materials can form and adhere to engine parts (especially piston rings, grooves and skirts) possibly having a deleterious effect on engine efficiency, operation and useful life.
• additives are added to lubricating oils to reduce the formation of such harmful materials and/or to keep them suspended so that the engine parts are kept clean and operating properly. Additives which reduce the tendency of lubricating oils to form oxidation products are called antioxidants, while additives which tend to suspend oxidation products and sludges are called detergents or dispersants. It is not uncommon for certain additives to exhibit both antioxidant and detergency properties.
• sulfurized metal phenates are quite useful as antioxidants as well as dispersants. These phenates are generally formed with an alkaline earth metal base, such as calcium, barium, magnesium, and strontium.
• overbased sulfurized phenates has been accomplished by several different processes.
• One such process involves the reaction of a phenol, sulfur and an alkaline earth metal base with carbon dioxide.
• the present invention relates to this type of process and is exemplified by U.S. Patents 3,036,971 and 3,194,761, which are expressly incorporated herein by reference.
• United States.Patent 2,916,454 to Bradley et al. discloses limiting the amount of carbon dioxide absorbed to a molar ratio of 0.2-0.6 carbon dioxide:phenolic compound. Bradley does not disclose the use of an inorganic earth metal base, such as calcium, but requires the use of complex metal alcoholates, such as barium, magnesium or sodium.
• U.S. Patent 3,036,971 to Otto discloses the reaction of an alkyl phenol, calcium hydroxide, sulfur, and a mutual solvent. Otto discloses limiting the amount of carbon dioxide absorbed to a molar ratio of 0.2-0.6 carbon dioxide:calcium. Nowhere is it disclosed in Otto to conduct the carbonation in stages to prevent the reaction product from becoming too viscous. Both of these patents fail to disclose the concept of limiting the amount of carbon dioxide absorbed to control bright stock solubility.
• U.S. Patents 3,178,368 to Hanneman and 3,336,224 to Allphin disclose the reaction of calcium sulfonate, a phenolic compound, mutual solvent, and a high molecular weight alcohol.
• the amount of carbon dioxide absorbed is limited to 0.1 to 3.0 moles of carbon dioxide per mole of phenolic compound.
• Nowhere is it disclosed in these ' patents to undercarbonate to control bright stock solubility or to add an alkaline earth metal base in stages to prevent an increase in the viscosity of the reaction product.
• both Hanneman and Allphin require the use of high molecular weight alcohols in the reaction. The use of these alcohols is economically unattractive because the alcohols are expensive and must be distilled out of the final product before blending.
• U.S. Patent 3,194,761 to Foy et al. discloses the reaction of a diluent oil, alkylphenol, hydrated lime, sulfur and a mutual solvent. Carbon dioxide is bubbled through the mixture until no more than 0.5 moles of carbon dioxide is absorbed per mole of calcium. Thereafter, an additional amount of hydrated lime is added.
• U.S. Patent 3,350,210 to Herd et al. discloses the reaction of hydrated lime, methanol and carbon dioxide at 10°-30°C. Thereafter phenol sulfide and a diluent are added. The amount of carbon dioxide absorbed is limited to 0.4-0.8 moles of carbon dioxide per mole of calcium.
• U.S. Patent 3,923,670 to Crawford discloses the reaction of an alkyl phenol, sulfur, an alkali metal hydroxide and ethylene glycol to which is added additional alkali metal hydroxide and carbon dioxide.
• Crawford there is no limit on the amount of carbon dioxide absorbed, and thus there is no suggestion of undercarbonating to improve bright stock solubility or to carbonate in stages to control viscosity.
• the present invention provides a novel overbased sulfurized phenate produced by the process comprising contacting at reaction conditions sulfur, a phenolic compound and an alkaline earth metal base to produce a phenate intermediate. Thereafter, the phenate intermediate is contacted at reaction conditions with an additional amount of the alkaline earth metal base and carbon dioxide, wherein the amount of carbon dioxide absorbed is in the ratio of about 0.75-0.95 moles per mole overbasing alkaline earth metal.
• overbasing alkaline earth metal is defined as the total moles of alkaline earth metal minus one-half of the moles of phenolic compound.
• the overbasing alkaline earth metal is (0.69 + 0.89) - (1.04/2) or 1.06 moles.
• the novel process of this invention comprises the reaction of sulfur, a phenolic compound and an alkaline earth metal base which is, in an amount insufficient to fully react with the phenolic compound, a mutual solvent and a diluent to produce a phenate intermediate.
• the alkaline earth metal base added in the sulfurization step to produce the phenate intermediate is from about 20% to 75% of the total amount added and, preferably from about 40% to 60%.
• the phenate intermediate is contacted with additional alkaline earth metal base and carbon dioxide bubbled into the mixture.
• the phenate intermediate can be contacted with the additional amount of the alkaline earth metal base in stages to control the viscosity of the reaction product.
• the phenate intermediate can be contacted with two additional charges of the alkaline earth metal base and carbon dioxide with the last charge being about 1C per cent smaller in volume that the previous additional charge. This procedure is especially useful in controlling the viscosity of the reaction mixture in large reaction vessels or under already high viscosity conditions.
• the amount of carbon dioxide absorbed should be in the ratio of about 0.70 to about 0:95 moles per mole of overbasing alkaline earth metal.
• Carbon dioxide can be added in the carbonation step along with or after the addition of the additional overbasing alkaline earth metal base. If the additional alkaline earth metal base is added in stages the carbon dioxide can be added (a) continuously while the alkaline earth metal base is added, (b) introduced after each addition is completed, or (c) added only after the final addition of alkaline earth metal base.
• the total base number (TBN) of the final overbased sulfurized phenate product of this invention can vary over a wide range; however, the TBN should be between 200 and 300, and preferably close to 250 TBN.
• the sulfur utilized is preferred to be elemental sulfur.
• Sulfur is used in an amount from about 0.3 to about 2.5 moles of sulfur per mole of total alkaline earth metal base incorporated. It is preferred to use from about 0.7 to about 1.25 moles of sulfur per mole of alkaline earth metal base incorporated.
• the phenolic compounds utilized are hydrocarbyl substituted phenols.
• the benzene ring can contain various other substituents such as chlorine, bromine, nitro and others.
• the most commonly used substituted phenols contain one or more hydrocarbyl groups having about 1 to about 100 carbon : atoms.
• the hydrocarbyl groups Preferably, the hydrocarbyl groups contain about 8 to about 20 carbon atoms.
• the hydrocarbyl groups can be alkyl, alkenyl, aralkyl or alkaryl. For reasons of cost and availability monoalkyl- phenols are preferred. Nonoalkyl substitution in the para position is preferred.
• Suitable hydrocarbon substitution can comprise low molecular weight groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl and the various isomers of pentyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl and the like, including low molecular weight polymers and copolymers.
• Commercially available substituted phenols contain from 8 to 20 carbon atoms substituents from polypropylene or polybutene.
• the hydrocarbyl substituted phenol can have other substituents, such as for example: chlorine, bromine, nitro, and the like.
• the alkaline earth metal base comprises a base of divalent metals such as calcium, barium, magnesium, and strontium.
• the preferred metal bases are the oxides and hydroxides of the various metals, such as calcium oxide, calcium hydroxide, barium oxide, barium hydroxide, magnesium oxide, and the like.
• Calcium hydroxide commonly called hydrated lime, is most often used in the manufacture of these phenates. It is preferred to use hydrated lime of good quality, relatively free of carbonates, which has not deteriorated during storage. In certain cases, the carbonate, methoxides or other forms of base may be used for certain metals such as magnesium.
• Both the sulfurization and the carbonation reactions can be conducted in the presence of a promoter or organic liquid which is sometimes referred to as a "mutual solvent.”
• the mutual solvent can comprise any stable organic liquid which has appreciable solubility for both the alkaline earth metal base and the phenolic compound and intermediate phenate.
• suitable solvents are glycols and glycol monoethers, such as ethylene glycol, 1,4-butene diol, and derivatives of ethylene glycol, such as the monomethyl ether, monoethyl ether, etc. Vicinal glycols are preferred and ethylene glycol is the most preferred since it serves to activate the neutralization reaction in the process and to that extent typifies a catalyst, although the exact characteristics describing its function are unknown.
• Both the sulfurization and the carbonation reactions can be conducted in a diluent, preferably a lubricating oil which remains unseparated from the final product.
• the reaction diluent serves to reduce the viscosity of the intermediate phenate. to make it readily transferable by pumping operations and the like.
• the amount of diluent used can vary over a wide range, but is used in a concentration to achieve a suitable intermediate or product viscosity for reaction and transfer while not unduly diluting the final product when the diluent will not be separated from the final product.
• Mineral lubricating oils are preferred as diluents since the ultimate use of the sulfurized metal phenates is often in oil additives.
• any inert water-insoluble organic medium which will not react or interfere with the reaction of the process is suitable.
• hydrocarbon oils and particularly petroleum oils are generally utilized in this process, other oils can also be used, such as synthetic, hydrocarbon, polymer oils prepared by condensation .or other methods.
• Light lubricating oils are particularly preferred and may be of a synthetic, animal, vegetable or mineral origin. Mineral lubricating oils are preferred by reason of their availability, general excellence and low cost.
• the lubricating oils preferred will be fluid oils, ranging in viscosity from about 40 Saybolt Universal Seconds at 100°F (38°C) to about 200 Saybolt Universal Seconds at 210°F (99°C).
• the molar ratios of the materials utilized in the present process can vary over a wide range depending upon the desired level of sulfur to be present in the final product and the desired TBN.
• the molar ratios for phenolic compound:alkaline earth metal base are about 1:0.4-2.
• the final product can have molar ratios of phenolic compound:alkaline earth metal base of about 1:0.5-0.7 for a low base material and about 1:1.5-1.8 for high based materials.
• the molar ratios for phenolic compound:sulfur can be 1:8-1.2 for low base materials and about 1:1.5-1.8 for high based materials.
• the molar ratios for phenolic compound:carbon dioxide can be about 1:0.5-1.3. However, it is critical that the molar ratio of carbon dioxide to overbasing alkaline earth metals be about 0.70 to about 0.95.
• the sulfurization and the carbonation reactions of this invention can be conducted at temperatures from about 200°F to about 400°F (94°C-205°C).
• the reactions are conducted at temperatures from about 300°F to about 360°F (148.8°-182.2°C). Higher temperatures within this range are preferred for several reasons.
• the higher temperatures aid in reducing the harmful effect of water in the reaction, which will be discussed in detail later, and to prevent phenate-sulfonate compatibility (PSC) problems.
• PSC problems can manifest themselves by the formation qf an insoluble, hazy substance in the product.
• the overbased sulfurized phenates produced by the present process can be mixed with any suitable lubricating oil bases or compositions.
• concentration of the overbased sulfurized metal phenates in the final lubricating oil composition depends upon the type of base oil used and the particular properties desired. The concentration can range from about 0.75 to about 15 weight per cent with the major portion of the lubricating oil composition being the oil.
• oils can be used such as naphthenic, paraffinic and mixed base oils, coal oils and synthetic oils.
• additives can be included in the final product to provide multifunctional properties, such as stabilizers, extreme pressure agents, tackiness agents, antiodor agents, pour point depressants, viscosity index improvers, antiwear agents, antioxidants, anticorrodants, metal deactivators, etc.
• the method of undercarbonating is accomplished by limiting the amount of carbon dioxide to about 0.7-0.95 moles of carbon dioxide per mole of overbasing alkaline earth metal.
• None of the prior art processes I know of contemplates (a) reacting sulfur, a phenolic compound and an amount of alkaline earth metal base insufficient to react with the phenolic compound to form a phenate intermediate, and (b) contacting the phenate intermediate with an additional amount of the alkaline earth metal base and carbon dioxide, wherein the amount of carbon dioxide absorbed is limited to 0.70-0.95 moles per mole of overbasing alkaline earth metal.
• alkaline earth metal base should not be reduced when undercarbonating because it is primarily the base which keeps the oxidation products suspended. It should be noted that I have found that undercarbonating below the limits disclosed can cause other problems. For example, if 0.5 moles of carbon dioxide per mole of overbasing alkaline earth metal is used in the present process, the carbonization would be incomplete and the final product would be unstable and not exhibit the required antioxidant and dispersant characteristics.
• a solvent can be used in place of the diluent oil to make the observable carbon dioxide absorption, the point at which no more carbon dioxide can be absorbed, to coincide exactly with the point at which the carbon dioxide introduction should be stopped to successfully undercarbonate the phenate product.
• an aromatic solvent such as xylenes or C 9 aromatics in lieu of all or a significant portion of the diluent oil will coalesce the observable and the optimum end points of the carbon dioxide absorption. Termination of carbon dioxide introduction at the observed point while using those solvents has resulted in overbased sulfurized phenates having excellent bright stock solubility.
• the preparation of the overbased sulfurized phenates using these solvents is essentially the same as has been described above; however, all or a portion of the diluent oil can be left out of the process. It is desirable to retain up to about 46 per cent of the normal amount of diluent oil to control the viscosity during the sulfurization step.
• the reaction mixture is cooled to under about 275°F when adding the xylene or C 9 aromatics, mutual solvent and calcium hydroxide. Carbonation is initiated when the reaction mixture has been heated to about 300° to 310°F, which is the reflux temperature of the C 9 aromatics or about 285°F for the xylenes.
• a mixture of water and mutual solvent, such as ethylene glycol, can be removed during the carbonation step to prevent water build up in the reaction vessel.
• the introduced solvents and other volatile materials are stripped from the reaction mixture as the required amount of diluent oil is added.
• the use of these solvents can be particularly helpful in undercarbonating the phenate product when utilizing very high viscosity starting materials or when the viscosity of the reaction mixture needs to be - especially low.
• aromatic solvents such as xylenes and C Q aromatics
• Paraffinic solvents such as 5-W oil and dodecane
• the two azeotropes, H 2 0 + xylenes and H 2 0 + dodecane have about the same composition and boiling points while 5-W oil + H 2 0 do not form an azeotrope and water removal is poor. Therefore, since xylenes and dodecane form similar types of azeotropes, the nature of the solvent used (polar vs. nonpolar) probably has an effect on micelle structure and hence on the ability to remove water from the process.
• Example I The same procedure was followed as in Example I except that carbon dioxide injection was continued until 1.08m were absorbed.
• the physical properties of the final product are shown in Table I.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Lubricants (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 1983
  • 1983-03-29 CA CA000424796A patent/CA1234155A/fr not_active Expired
  • 1983-04-07 EP EP83301955A patent/EP0091789A3/fr not_active Ceased
  • 1983-04-07 JP JP6009283A patent/JPS58185558A/ja active Granted

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