A lubricating composition includes an oil of lubricating viscosity and an N-substituted hydroxyaromatic succinimide or a salt thereof.

This invention relates to the use of a metallic or non-metallic detergent which is a hydrocarbyl-substituted salicylic acid or a derivative thereof in a non-aqueous lubricant composition as an inhibitor of lead corrosion associated with ashless, organic ester, anti-wear additives and/or friction modifiers.

Described are multi-ring antioxidant products comprising at least one sulfur-bridged aromatic hydrocarbon compound substituted on at least one of its aromatic rings by at least one sterically hindered 3,5-dihydrocarbyl-4-hydroxybenzyl moiety. Such products have the formula:
R—S.sub.n—R[—S—R].sub.m
wherein each R is, independently, an aromatic hydrocarbon group having 6-12 carbon atoms, wherein m is 0-20, wherein n is 1-6 when m is 0, and when n is 1, m is 1-20; and wherein at least one of R, R.sup.1, and R.sup.2 is substituted by at least one such sterically hindered moiety. The preparation of such products and their use as antioxidants in compositions normally susceptible to oxidative degradation in oxygen or air, e.g., liquid fuel and lubricants, are also described.

A bridged alkaline earth metal alkylphenate having reduced monomeric alkylphenol is prepared by reacting (a) a 4-alkylphenol, unsubstituted at the ortho positions, (b) an alkaline earth metal oxide or hydroxide, (c) a bridging agent comprising sulfur or a carbonyl compound of 1 to about 6, or to 4 or to 2, carbon atoms, and (d) a 2,6-dialkylphenol. The amount of the 2,6-dialkylphenol is 0.05 to 3 moles per 1 mole of the 4-alkylphenol; if there is a molar excess of the 2,6-dialkylphenol, then the excess is added after initial reaction.

The invention relates to a lubricant comprising a polyalkylene glycol basestock, an aromatic amine of the formula (I) as defined hereinafter, and a thioether of the formula (II) as defined hereinafter. The invention further relates to a method for preparing the lubricant comprising the step of contacting the polyalkylene glycol basestock, the aromatic amine of the formula (I), and the thioether of the formula (II); and to a method for reducing the oxidative degradation of the lubricant comprising the step of contacting the polyalkylene glycol basestock, the aromatic amine of the formula (I), and the thioether of the formula (II).

##STR00001##

The invention provides a lubricating composition containing an oil of lubricating viscosity, an ashless thiocarbamate compound having an optionally-substituted hydrocarbyl group on an S-atom and an optionally-substituted hydrocarbyl group on an N-atom, and a boron-containing compound. The invention further relates to a method of lubricating an internal combustion engine with the lubricating composition.

A lubricating composition includes at least one base oil, at least one borated dispersant, at least two antioxidants selected from amine antioxidants, phenolic antioxidants substituted with one or more linear or branched alkyl groups having from 1 to 30 carbon atoms, and mixtures thereof, and at least one phosphite polymer having the formula (I) wherein: - each of the R.sup.1, R.sup.2, R.sup.3 and R.sup.4 can be independently selected from the C1-C20 alkyl, C3-C22 alkenyl, C6-C40 cycloalkyl, C7-C40 cycloalkenyl, C1-20 methoxy alkyl glycol ethers and Y-OH groups; - Y is selected from C2-C40 alkylene, C2-C40 alkyl lactone, —R.sup.7— N(R.sup.8)—R.sup.9— groups, in which R.sup.7, R.sup.8 and R.sup.9 are independently selected from hydrogen, C1-C20 alkyl, C3-C22 alkenyl, C6-C40 cycloalkyl, C7-C40 cycloalkenyl, C1-20 methoxy alkyl glycol ethers; - m is an integer from 2 to 100; - n is an integer from 1 to 1000.

The disclosed technology provides a lubricating composition and a method of lubricating an internal combustion engine where the lubricating composition contains an oil of lubricating viscosity, one or more metal-containing, sulfur-free, alkyl-phenol based detergents, an alkaline earth metal sulfonate detergent, a polyisobutenyl succinimide dispersant, and a dispersant viscosity modifier having a number average molecular weight of at least 20,000. The lubricating composition of the present invention can be formulated to have lower HTHS viscosity, and reduced phosphorous content, while providing protection against adhesive wear.

A lubricating oil composition can include a major amount of an oil of lubricating viscosity and a minor amount of an alkaline earth metal phenol-based detergent. The lubricating oil composition can further have a BN of greater than 140 mg KOH/g, and further wherein the marine diesel cylinder lubricating oil composition is substantially free of unsulfurized tetrapropenyl phenol and its unsulfurized metal salt.

A lubricating composition includes a sulfurized oxy-substituted aromatic polyol compound and an oil of lubricating viscosity. The sulfurized oxy-substituted aromatic polyol compound includes at least one of a sulfurized oxy-substituted aromatic polyol and a salt of a sulfurized oxy-substituted aromatic polyol. The compound is suitable as a replacement for detergents that contain C.sub.n alkyl phenols derived from oligomers of propylene.