A lubricating composition suited to use in a marine diesel engine includes an oil of lubricating viscosity and an amino carboxylate compound of formula (I): NR.sup.1R.sup.2((CHR.sup.3).sub.xNR.sup.4).sub.n(CHR.sup.5).sub.2COY, where R.sup.1 and R.sup.2 are independently selected from (CHR.sup.6).sub.2COY, H, and C.sub.1C.sub.3 alkyl and wherein at least one of R.sup.1 and R.sup.2 is (CHR.sup.6).sub.2COY; or wherein NR.sup.1R.sup.2 is a cyclic structure; Y and Y are independently selected from OR.sup.4, NHR.sup.7, and N(R.sup.7).sub.2; each R.sup.7 is independently selected from C.sub.6-C.sub.12 alkyl and C.sub.6-C.sub.12 alkenyl; R.sup.3, R.sup.5 and R.sup.6 are independently selected from H and C.sub.1-C.sub.4 alkyl; R.sup.4 is selected from H, C.sub.1-C.sub.4 alkyl, and (CHR.sup.3).sub.xNH.sub.2; x is from 2 to 4; and n is at least 1, except where NR.sup.1R.sup.2 is a cyclic structure, where n is at least 0.

The present invention provides a biodegradable lubricating oil composition containing 50% by mass or more of a synthetic ester base oil (A), 0.1 to 3% by mass of an amine-based antioxidant (B1), 0.1 to 3% by mass of a phenol-based antioxidant (B2), and 0.01 to 2% by mass of a sulfur-phosphorus-based extreme-pressure agent (C), wherein the transmittance at 3,0051 cm.sup.1 of a 0.1 mm-thick liquid film of the composition, as measured through IR absorptiometry, is 50% or more.

An oil composition comprising a first component having pendant groups and a second component but free of a third component and process for making such oil composition, where a single molecule of the third component can form large shearable stable complex structure with two molecules of the first component via van der Waals force between pendant groups and the terminal carbon chains, and a single molecule of the second component is capable of adjoining no more than one molecule of the first type. The oil composition has high shear stability making it suitable for use in lubricants subject to repeated high shear stress events.

An oil composition comprising a first component having pendant groups and a second component but free of a third component and process for making such oil composition, where a single molecule of the third component can form large shearable stable complex structure with two molecules of the first component via van der Waals force between pendant groups and the terminal carbon chains, and a single molecule of the second component is capable of adjoining no more than one molecule of the first type. The oil composition has high shear stability making it suitable for use in lubricants subject to repeated high shear stress events.

Provided herein are dielectric fluids comprising at least one estolide compound of formula: ##STR00001##
in which n is an integer equal to or greater than 0; m is an integer equal to or greater than 1; R.sub.1, independently for each occurrence, is selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; R.sub.2 is selected from hydrogen and optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched; and R.sub.3 and R.sub.4, independently for each occurrence, are selected from optionally substituted alkyl that is saturated or unsaturated, and branched or unbranched. Also provided herein are uses of dielectric fluids and electrical devices such as transformers that comprise a dielectric fluid comprising at least one estolide compound.

The present invention relates to heat transfer systems and methods involving zinc-containing surfaces in contact with a working fluid comprising refrigerant, lubricant and a protective agent comprising a compound according to Formula I:

##STR00001##

where R and R.sup.1 are each independently selected from the group consisting of hydrogen, alkyl, hydroxyalkyl and alkylthio, provided that at least one of R and R.sup.1 is alkylthio.

A refrigerating machine oil containing a hydrocarbon base oil having a 90% distillation temperature of 270 C. or lower.

A working fluid filled in a refrigerant circulation system comprising a compressor, a condenser, an expansion mechanism, an evaporator, and an accumulator, the working fluid comprising: a refrigerant; and a refrigerating machine oil, wherein the refrigerant comprises a hydrocarbon refrigerant having 2 to 4 carbon atoms, the refrigerating machine oil has a mixed aniline point of 20 C. or higher and 50 C. or lower and a viscosity index of 110 or more, an amount of the refrigerant dissolved in the working fluid is 40% by mass or less under conditions of a temperature of 80 C. and an absolute pressure of 2.8 MPa, and the refrigerating machine oil has a kinematic viscosity at 10 C. of 200 mm.sup.2/s or more and 3000 mm.sup.2/s or less.