Circulating oils with improved oil life and energy efficiency

Abstract

Circulating oil compositions and methods of use thereof. Circulating oil compositions may comprise a base oil and a performance additive package, the base oil comprising: at least a first base stock and a second base stock; where the first base stock is an OTL oil base stock having a molar ratio of pendant methyl groups to a-methyl groups of from 1.2 / 1 to 5.4 / 1, as determined by carbon 13 nuclear magnetic resonance (13CNMR); and wherein the second oil base stock comprises one or more Group I, Group II, Group II+, Group III, Group III+, Group IV, or Group V oil base stocks, or any combination thereof. Methods of improving energy efficiency and / or oxidation stability of a circulating oil composition may comprise providing said base oil for the circulating oil composition, and optionally, blending said base oil with said performance additive package, thereby forming said circulating oil composition.

Description

CIRCULATING OILS WITH IMPROVED OIL LIFE AND ENERGY EFFICIENCYFIELD OF IN VENTION

[0001] This application relates to lubricant oil compositions having improved oil life and energy efficiency and, more particularly, to circulating oil compositions and methods of use thereof.BACKGROUND

[0002] Base oils are a major constituent in industrial oils and contribute significantly to the final properties of these products, such as low temperature performance, biodegradability; energy efficiency, and high temperature thermal and oxidative stability. Each base oil possesses distinct characteristics that are needed to satisfy the specific operation requirements of a particular industrial oil formulation.

[0003] Circulating oils, for example, are oils that are used for centralized lubrication of various systems in industrial machines, such as bearings and gears. Circulating oils contain two general components, namely, one or more oil base stocks and additives. Circulating oils operate under conditions of high temperature, exposure to filtration operations, long oil drain intervals, and contact with moisture and other contaminants. Further, circulating oils require exceptional oil life, often tens of thousands of hours. Due to the millions of gallons of these oils used annually, circulating oils must have excellent thermal stability, oxidative stability, filterability, foaming resistance, compatibility with multiple materials, low traction coefficient, low temperature fluidity, and high film thickness at high temperatures. There is a desire to improve the oil life by improving the oil oxidative and shear stability, as well as to improve the oil energy efficiency by reducing the oil coefficient of traction. By improving the energy efficiency of and by extending the life of circulating oils, significant sustainability benefits in energy savings and reduced production of waste oil can be achieved.SUMMARY OF INVENTION[0004| Various details of the present disclosure are hereinafter summarized to provide a basic understanding. This summary is not an exhaustive overview of the disclosure and is neither intended to identify certain elements of the disclosure, nor to delineate the scope thereof. Rather, the primary' purpose of this summary is io present some concepts of the disclosure in a simpli fied form prior to the more detailed description that is presented hereinafter.

[0005] According to an embodiment consistent with the present disclosure, circulating oil compositions comprise a base oil and a performance additive package, wherein the base oil comprises at least a first oil base stock and a second oil base stock: wherein the first oil base stock is an OTL oil base stock having a molar ratio of pendant methyl groups to a-methyl groups of from 1 .2 / 1 to 5.4 / 1, as determined by carbon 13 nuclear magnetic resonance spectroscopy (l3C'NMR); and wherein the second oil base stock comprises one or more Group I, Group II, Group II+, Group III, Group HR. Group IV, or Group V oil base stocks, or any combination thereof.

[0006] In another embodiment, methods for improving the energy efficiency and / or the oxidation stability of a circulating oil composition comprise: providing a base oil for a circulating oil composition, the base oil comprising at least a first oil base stock and a second oil base stock, wherein providing the base oil optionally comprises blending the first oil base stock with the second oil base stock; optionally, blending the base oil with a performance additive package, thereby forming the circulating oil composition; wherein the base oil comprises at least a first oil base stock and a second oil base stock: wherein the first oil base stock is an OTL oil base stock having a molar ratio of pendant methyl groups to a-mcthyl groups of from 1.2 / 1 to 5.4 / 1 , as determined by carbon 13 nuclear magnetic resonance spectroscopy (BCNMR); and wherein the second oil base stock comprises one or more Group I, Group II, Group II+, Group Ill, Group III+, Group IV, or Group V oil base stocks, or any combination thereof.[0007| Th ese and other features and attributes of the disclosed compositions and methods of the present disclosure and their advantageous applications and / or uses will be apparent from the detailed description which follows.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 A-I D shows the traction coefficient as a function of slide to roll ratio (SRR) of a circulating oil formulation with olefin-to-liquid (OTL or ETL) 40 (IE1) as compared to a corresponding circulating oil formulation with polyalphaolefin (PAO) 40 (GER

[0009] FIG. 2A-2D shows the traction coefficient as a function of SRR of a circulating oil formulation with a blend of ETL 100 and PAO 6 (IE3) as compared to a corresponding circulating oil formulation with PAO 100 and PAO 6 (CE2).

[0010] F IG. 3A-3D shows the traction coefficient as a function of slide to roll ratio (SRR) of a paper machine oil formulation with ETL 40 (IE) as compared to a corresponding paper machine oil formulation with PAO 40 (CE).

[0011] FIG. 4 shows the traction coefficient as a function of slide to roll ratio (SRR) of a paper machine oil formulation with blends of PAO 6 with ETL 100 (TEI ) or ETL 40 (IE2) as compared to a corresponding paper machine oil formulation with blends of PAO 6 with PAO 100 (CE1), metallocene PAO (mPAO) 100 (CE2), PAO 40 (CE3), or EHC 340 Max™ (CE4).

[0012] FIG. 5 shows the molecular weight curve of ETL 100 vs PAO 100 as determined from gel permeation chromatography (GPC) (Calibration: linear polyethylene (polystyrene standard) in the 500 - -6-7 million g / mol; temperature 145°C, solvent ™ l,2,4~trichk)robenzene, refractive index detection).

[0013] FIG. 6A shows Fourier Transform Ion Cyclotron Resonance Mass Spectrometry with Laser Desorption Silver ionization (FT- ICR MS with LDI (Ag)) spectra of mPAO 100, PAO 100, ETL 100, and EAO 100, where differences in peak spacing indicate differences in degree of branching and branch size. FIG. 68 shows FT- ICR MS with LDI (Ag) spectra of ETL 100, ETL 40, and PAO 100.

[0014] FIG. 7 A shows carbon 13 nuclear magnetic resonance (i3CNMR) chemical shifts observed for a branched hydrocarbon. FIG. 7B shows a comparison off 3tNMR spectra of ETL oil base stocks vs. GTL 8 (Shell QHVI 8), PAO 10 (Spectrasyn 10), PAO 100 (Spectrasyn 100), and EAO 100 (Lucan t IIC-100) oil base stock.

[0015] FIG. 8A shows a chart plotting the{X;.NMR molar ratio of pendant methyl groups- alpha carbons on the y-axis versus theiXN.MR molar ratio of epsilon carbons methyl branches on the x- axis for each of ETL 40 and ETL 100 oil base stocks. FIG. SB shows a chart plotting theIXNMR molar ratio of pendant methyl groups / alpha carbons on the y-axis versus the ’JCN.MR molar ratio of epsilon carbons, methyl branches on the x-axis for each of ETL 40 and ETL 100 oil base stocks as well as other commercial oil base stocks. FIG. 8C shows a chart plotting, XNMR methyl branches vs.I5CNMR epsilon carbons. FIG. 8D shows a chart plottingUCNMR alpha carbons vs.I XNMR. pendant methyl groups. FIG. 8E shows ’XNM.R pendant methyl groups vsUNMR epsilon carbons.

[0016] FIG, 9A shows a chart of the volati lity (TGA NO ACK %Off) vs. viscosity (K V 100) of ETL oil base stocks as compared to GTL and PAO oil base stocks. FIG. 9B shows the viscosity index (VI) versus viscosity (KV40) of ETL oil base stocks, as compared to GTL and PAO oil base stocks. FIG. 9C shows the pour point of ETL oil base stocks as compared to GTL and PAO oil base stocks.

[0017] FIG. 10A shows the Rotary Pressure Vessel Oxidation Test (RPVOT) oxidative stability (min) or the DSC oxidative induction temperature (°C) (performed by Pressure Differential Scanning Calorimetry (PDSC)) of ETL oil base stocks, as compared to PAO and GTL oil base stocks. FIG.I OB shows the oxidative stability as a comparison of the viscosity (KV100, cSt) before and after RPVOT testing for ETL oil base stocks, as compared to PAO and GTE oil base stocks.

[0018] FIG. 1 1 A-l I B shows the shear stability (viscosity (KV I OOj change after a KRL20 Shear Stability Test) of ETL 100 (FIG. 11 A) or ETL 40 (FIG. 1 IB) oil base stock vs PAO 100 (Spectrasyn “SS” 100) (FIG. HA) or PAO 40 (Spec-trasyn “SS” 40) (FIG. 1 I B).

[0019] FIG. 12A-12B shows plots of the traction coefficient versus SRR (%) of ETL 100 oil base stocks versus PAO 100 oil base stocks.

[0020] FIG. 13 shows a plot of the traction coefficient versus SRR (%) for ETL 100 versus PAO 100 and FAO 100 (e.g., Lucant™ IlC-iOO) oil base stocks.DETAILED DESCRIPTIONDefinitions

[0021] As used herein, the term “wt,%” indicates percentage by weight, the term “vol.%” indicates percentage by volume, the term “mol%” indicates percentage by mole, the term “ppm” indicates parts per million, and the terms “ppm wt.” and “wppm” are used interchangeably and refer to parts per million on a weight basis. As used herein, the term “wt ratio” indicates weight ratio, the term “vol. ratio” indicates volume ratio, and the term “mol ratio” indicates mole ratio. All concentrations herein, unless otherwise stated, are expressed on the basis of the total amount of the composition in question.

[0022] .As used herein, the term “base oil”, and grammatical variations thereof; refer generally to the fluid component of a lubricant formulation or lubricating oil formulation, which may comprise one or more different oil base stocks.

[0023] As used herein, the terms “lubricant”, “lubricating oil”, and grammatical variations thereof, refer generally to a substance (usually a fluid under operating conditions) suitable for introduction between two moving surfaces of a system to reduce the friction and wear between said surfaces.

[0024] An oil base stock, as described herein, may be defined according to the American Petroleum Institute (API) base oil classification system, which categorizes oil base stocks into five groups based on their saturated hydrocarbon content, sulfur level, and viscosity index. Oil base stocks are typically produced in large scale from non-renewable petroleum sources. Group 1 and II oils are refined crude oils ha ving a viscosity index (VI) of about 80-120. Group 1 oils are the least refined, undergoing only solvent refining, and comprise less than 90% saturates and / or greater than 0,03% sulfur. Group I I oils are more refined, both solvent refined and hydrocracked. Group II I oil base stocks are refined crude oils which undergo severe hydroprocessing (e,g.. Group III oil base stocks may be hydrocracked,hydroisomerized, and hydrotreated) to achieve the same standards as Groups I-II, while having a VI of greater than 120. Designations commonly used by oil producers, but not officially recognized by the API, include Group 11 + oil base stocks (c.g., further hydrotreated) having a VI of approximately 110-120 and Group II R oil base stocks (e.g. , coal-to-liquid (CTL) oil base stocks, gas-to-liquid (GTL) base stocks produced, or the like, (e.g., by Fischer-Tropsch reactions of hydrogen and carbon monoxide) having a VI of approximately 135-145. Group IV oil base stocks include synthetic oils comprising polyalphaolefins (PAOs) (e.g., produced by oligomerization of alpha olefins, such as l- decene, 1 -butene, and propene), with a VI of 125-200. Group V base stocks include all base stocks that do not belong to Groups MV, such as naphthalenes, polyalkylene glycols (PAG), and esters.

[0025] An oil base stock may be alternatively defined by a viscosity and / or volatility grade classification, which varies from producer to producer. Generally, viscosity grade classifications range, in order of increasing viscosity and mid-point boiling point, from light neutral, medium neutral, to heavy neutral. An oil base stock may be defined by a cold cranking viscosity (“CCS”) determined using ASTM D5893, which is the Standard fest Method for Apparent Viscosity of Engine Oils Between -5 and -35 C Using the Cold Crank Simulator. An oil base stock may also be defined by a Noack volatility, determined using ASTM D5800-10, which is the Standard Test Method for Evaporation Loss of Lubricating Oils by the Noack Method. An oil base stock may be defined as a “Trim Stock”, which refers to an oil base stock that may be blended at a lesser amount with other oil base stocks to bring a viscosity, CCS value, and or a Noack volatility of a blended base oil into a desired range.Overview

[0026] This application relates to compositions suitable for use as lubricants and, more particularly for use as circulating oils, and methods concerning the same. The present disclosure provides circulating oil formulations comprising a base oil comprising a blend of an olefin-to-liquid (“OTL”) oil base stock and a co-oil base stock,|0027| Circulating Oil Formulations

[0028] The present disclosure includes methods and compositions related to circulating oil formulations comprising a base oil and optionally one or more additives. Circulating oil formulations of the present disclosure may be specifically formulated for improved performance, particularly for improved energy efficiency and / or improved oil life. In one embodiment, circulating oils of the present disclosure may target improved viscometries, low temperature fluidity, film thickness, traction, intcrfacial properties, oxidative stability, volatility, or the like, or any combination thereof.The circulating oils of the present disclosure may exhibit increased viscosity index and reduced coefficient of traction, thus critically improving energy efficiency performance compared to typical circulating oil formulations. Unexpectedly, the circulating oils of the present disclosure may achieve equivalent or improved properties as compared to typical circulating oils, e.g., PAO-based formulations, CTL-based formulations, GTL-based formulations, ethylene-a-olefin copolymer (EAO)-based formulations (e.g., C2-olefin / C3-olefin copolymers, e.g., Locant*Mseries (Mitsui Chemicals)) or the like.[0029| Base Qi Is .for Circulating Qi[0030j Base oils of the present disclosure comprise a blend of an OTL oil base stock and a co-oil base stock. Base oils of the present disclosure may comprise various amounts of an OTL oil base stock. OTL oil base stocks may be included in a circulating oil formulation at from about 10 wt.% to about 75 wt.%, including all wt.% values and subsets therebetween, based on the total weight of the circulating oil formulation (e.g., from about 15 wt.% to about 70 wt.%, from about 20 wt.% to about 65 wt.%, from about 25 wt.% to about 60 wt.%, from about 30 wt.% to about 55 wt.%, from about 35 wt.% to about 50 wt.%, or from about 40 wt.% to about 45 wt.%). Base oils of the present disclosure may comprise various amounts of a co-oil base stock. A co-oil base stock may be present in the circulating oi l formulations of the present disclosure from about 15 wt.% to about 90 wt.%, including all wt.% values and subsets therebetween, based on the total weight of the circulating oil formulation (e.g., from about 15 wt.% to about 30 wt.%, from about 20 wt.% to about 25 wt.%, from about 20 wt.% to about 85 wt.%, from about 25 wt.% to about 80 wt.%, from about 30 wt.% to about 75 wt.%, from about 35 wt.% to about 70 wt.%, from about 40 wt.% to about 60 wt.%, or from about 45 wt.% to about 55 wt.%).

[0031] Base oils of the present disclosure may have various improved performance values. A base oil of the present disclosure may have improved performance as compared to typical base oils where a base oil of the present invention replaces a typical base oil stock with an OTL oil base stock) (e.g., where the base oils are matched for rheological properties). Improved performance may be observed where a portion of or all of a typical PAO, CTL, GTE, or EAO oil base stock of a base oil is replaced with an OTL. oil base stock. A base oil of the present disclosure may display a lower coefficient of traction, a higher fluidity at a lower temperature, a greater film thickness at a higher temperature, an increased oxidation stability, the like, or any combination thereof, as compared to a typical base oil (e.g., a P AO-based, a CTL-based, a GTL-based, or an ethylene-a-olefin copolymerbased base oil). A base oil of the present disclosure may display from about 5% to about 40%improved performance properties, including all % values and subsets therebetween (e.g., from about 10% to about 30% improved performance).

[0032] OTL Oil Base Stocks for Base Oils of Circulating Oil Formulations

[0033] I he base oils of circulating oil formulations of the present disclosure comprise an OTL oil base stock. The OTL oil base stock used in base oil formulations of the present disclosure may comprise one single OTL. oil base stock or two or more different OTL oil base stocks. OTL oil base stocks may exclude naphthenes and aromatics (e.g., group I and group II base oil stocks). OTL oil base stocks of the present disclosure may be polymeric hydrocarbon fluids derived from one or more olefin monomers, isomers thereof, or any combination thereof. O'LL oil base stocks may be derived from one or more C2 C I 2 olefins (e.g,, one or more C2-C8 olefins), one or more >C12 olefins, isomers thereof or any combination thereof. OTL oil base stocks may be derived exclusively from ethylene. Alternatively, O TL oil base stocks may be derived from ethylene and at least one of a group consisting of C3-C12 olefins (e.g., C3-C8 olefins or C3-C6 olefins), one or more >C12 olefins, isomers thereof and any combination thereof In an embodiment, the OTL oil base stock may be derived from ethylene and at least one of a group consisting of C3-C6 olefins and isomers thereof C3-C6 olefins and isomers thereof may comprise one or more olefins of the group consisting of propylene, C4 olefins, C5 olefins, C6 olefins, isomers thereof and any combination thereof («.<>., propylene, 1 -butene, 2~butene, isobutylene, I -pentene, 2-pentene, 2-methyi-I -butene, 3-methyl- l - butene, 2-methyl-2-butene, 1 -hexene, 2 -hexene, 3-hexene, 2-methyl-l -pentene. 3-methyl~l -pentene, 4-methyl~l -pentene, 2-methyl~2-pentene, 3-methyl-2-pentene, 4-methyl~2-pentene, 2,3-dimethyi-l- butene, 3, 3 -dimethyl-. I -butene, 2,3-dimethyl-2-butene, 2 -ethyl- 1 -butene, and the like, and any combination thereof). As used herein, the terms “oil-to-liquid”, “OTL oil base stock”, and “OTL oil’’ may also be referred to herein as an “ethylene-to-liquid”,WETL oil base stock”, or “ETL oil”, however, such terms do not limit said oils to polymers derived exclusively from ethylene monomers.

[0034] Polymerizations used to prepare OIL. oil base stocks may use an olefin polymerization catalyst (e.g,, a nickel a-diimine catalyst system, the like, or any combination thereof). Polymerizations used to prepare OTL oil base stocks may be performed in the presence of activators (e.g., triethyl aluminum, the like, or any combination thereof). OTL. oil base stocks of the present disclosure may be prepared by olefin polymerization, followed by hydrogenation. Exemplary OTL. oil base stocks of the present disclosure, and methods of making thereof, may be disclosed in any one of patent numbers CN 10336051713, CN 10550376313, CN 10564675613, CN103183624B, CN 10278643513, CN1 16286149 A, CN116286150 A, US 10961329, US 10294440, or internationalpatent application numbers WO2012155764, WO2016058559, or WO202183238A1 , each of which is incorporated herein in its entirety.

[0035] OTL oil base stocks of the present disclosure may have various molecular weights (e.g., number-average molecular weight (MB), weight-average molecular weight (Mw), z-average molecular weight (MO). Various methods of determining molecular weight may be used, such as gel permeation chromatography (GPC) (e.g., high temperature GPC), laser light scattering (<?.g., high temperature laser light scattering), Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT- ICR M S), the like, or any combination thereof). In one embodiment, OTL oil base stocks may have a molecular weight (e.g., Mri, Mw, and or XL ) of from about 300 to about 500,000 grams per mole (g / mol), inchiding all g / mol values and subsets therebetween (eg.. from about 400 g / mol to about 1000 g / mol, from about 700 g / mol to about 1100 g / mol, from about 800 g / mol io about 200,000 g / mol, from about 1000 g mol to about 100,000 g / mol, or from about 300,000 g / mol to about 500,000 g / mol). In one embodiment, OTL oil base stocks may have a polydispersity (Ma / Mw) of from about 1 .3 to about 1.8, including all values and subsets therebetween (e,g., from 1.4 to 1.8). In one embodiment, OTL oil base stocks have a slightly lower number average molecular weight (M»), weight -average molecular weight (Mw), z-average molecular weight (Mz), and or polydispersity, as determined by GPC analysis, than traditional oil base stocks, e.g., FAO ail base stocks, GTL oil base stocks, EAO oil base stocks, of similar kinematic viscosity, e.g., KV100.

[0036] Branching of OTL Oil Base Stocks

[0037] In an embodiment, OTL oil base stocks may be differently branched and / or less regularly structured, as compared to other oil base stocks. In an embodiment, O IL. oil base stocks are differently branched and or less regularly structured, as compared to PAO oil base stocks, GTL. oil base stocks, and / or EAO oil base stocks. OTL base stocks may comprise a mix of methyl and longer (<?.g., >C4) straight chain alkyl branches irregularly distributed throughout the structure. OTL oil base stocks may comprise various number of >C4 length linear alkyl branches per molecule. The > C4 length linear alkyl branches may comprise butyl groups, pentyl groups, hexyl groups, heptyl groups, octyl groups, nonyl groups, decyl groups, the like, and any combination thereof. OTL oil base stocks may further comprise Cl -C3 alkyl branches. In one embodiment, OIL oil base stocks may comprise from about 6 to about 10 C1-C3 alkyl branches per 100 carbons, including all number of C1-C3 alkyl branches per 100 carbon values and subsets therebetween (e.g. , from about 6.5 to about 8 C 1 -C3 alkyl branches per 100 carbons). In contrast, comparative oil base stocks such as PAO exclusively comprise long branches arranged in a regular structure, oil base stocks such as GTL comprise greater terminal methylgroups versus methyl branches and having greater wax-like character in the middle of the molecule, and oil base stocks such as EAOs (<?.g., LucanrS Mseries (Mitsui Chemicals)) exclusively comprise short methyl branches regularly spaced throughout the structure of a long backbone.

[0038] Unexpectedly, OTL oil base stocks of the present disclosure may provide improved performance in a base oil or formulated lubricant (eg. equivalent or lower coefficient of traction, higher low temperature fluidity, or the like) as compared to oil base stocks with less branching and a more regular structure (e.g., when matched for rheological properties). Oils with less branching and a more regular structure, (c.g,. Group UH oil base stocks, e.g,, GTL oil base stocks) typically do not display low temperature fluidity, as higher van der Waals forces increase the pour point and waxiness of linear fluids as compared to more branched molecules.

[0039] OTL oil base stocks of the present disclosure may have various branching properties. Various analytical techniques may be used to determine branching properties (e.g., proton nuclear magnetic resonance (HNMR), carbon 13 NMR (L>CNMR). Distortionless Enhancement by Polarization Transfer (DEPT),3CNMR (DEPT-,x;NMR), attached proton test,3C:NMR (APT-! JCNMR), Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS), FT-ICR MS with Laser Desorption Silver Ionization (EDI (Ag)) (FT-ICR MS with LDI (Ag)), Gel Permeation Chromatography (GPC), the like, and any combination thereof).

[0040] Molar Ratio of Total Meth yl Groups to Short Chain Methyl Branches

[0041] Various branching properties of OTL oil base stocks may be determined by proton nuclear magnetic resonance (HNMR). O TL oil base stocks may comprise various numbers of total methyl groups. In one embodiment, total methyl groups may be determined by detection of aMNMR chemical shift at about 0.30 ppm to about 0.96 ppm. In one embodiment, OTL oil base stocks comprise from about 15 mol% to about 17 mol% of total methyl groups, including all mol% values and subsets therebetween (c.g., from about 16 mol% to about 16.5 mol% of total methyl groups).

[0042] O TL oil base stocks may comprise various numbers of short chain methyl branches. As used herein, the term ‘“short chain methyl branches'”, and grammatical variations thereof, refer io the sum of the number of pendant methyl groups or methyl groups at the terminus of >C2 length alkyl branches pendant from an alkyl backbone. In one embodiment, short chain methyl branches may be determined by aHNMR chemical shift at about 0.79 ppm to about 0.86 ppm. In one embodiment, OTL oil base stocks comprise about 16 mol% of short chain methyl branches.

[0043] OTL oil base stocks may comprise various molar ratios of total methyl groups to short chain methyl branches. In one embodiment, OTL oi l base stocks may have a molar ratio of total methylgroups to short chain methyl branches of about 1.1 / 1 to about 1 .8 / 1 , including all values and subsets therebetween (eg., about 1.2 / 1 to about 1.6 / 1 , or about 1.3 to about 1.5.1 ).

[0044] Molar Ratio of Total Methylene and Methine Groups to Total Methyl Groups[00451 OTL oil base stocks may comprise various numbers of total methylene and methine groups. In one embodiment, total methylene and methine groups may be determined by detection of aHNMR chemical shift at about 0.97 ppm to about 3.03 ppm. OTL oil base stocks may have various molar ratios of total methylene and methine groups to total methyl groups. In an embodiment, OTL oil base stocks may have a molar ratio of total methylene and methine groups to total methyl groups (as determined above) of from about 2. 12 / 1 to about 4.5 / 1 , including all values and subsets therebetween from about 4.1 / 1 to about 4.5 / 1),

[0046] Molar Ratio of Pendant Methyl Groups to Alpha Methyl Groups[0047| Various branching properties of OTL oil base stocks may be determined by high resolution carbon 13 nuclear magnetic resonance spectroscopy (BCNMR) experiments. In one embodiment,!3VNMR experiments described herein were performed according to LISI 1186787, incorporated by reference herein in its entirety. In one embodiment,i3CNMR experiments described herein were performed at a frequency of 150.9028 MHz on a Broker A vance spectrometer at a proton frequency of 600 MHz. Generally, samples were prepared 30% by volume in CDClj.l ,cN MR experiments were performed with Cr(acac) added as a relaxation agent.IXNMR experiments were performed at room temperature with a 90-degree pulse, 5-second delay between successive experiments and 1024 scans were accumulated. D'EPT (Distortions Enhancement by Polarization Transfer)f !CN.MR (DEPT-NMR) experiments described herein were performed to confirm the peak assignments based on proton multiplicity: C, ( I L ( 11?, Gi l?. The entire spectrum was integrated to determine the mole % of the different integrated areas. Statistical information on branching, length of branches, distribution of the branches along the molecule, free molecular ends and unbranched regions along the backbone of the isoparaffin were determined. Particularly, carbons in long chains, referred to as epsilon carbons (s-C) at 29.5-30 ppm were measured. The epsilon carbon corresponded to carbons in chains five or more from the end of a chain, four or more from a branch and two or more from an aromatic ring. The chain end carbons a, p, y, 6 occur at 14.12, 22.69, 31.92 and 29.36 respectively. Since the distribution of molecules in the samples is large and there are millions of different types of molecules, such an analysis is necessarily statistical.

[0048] OTL oil base stocks may comprise various number of pendant methyl (“P-Me”) groups per molecule. As used herein, the term “P-Me groups”, and grammatical variations thereof refergenerally to methyl group branches (i.e., methyl groups branching from an alkyl chain of length > four (4)) and flanked by two methylene carbons anywhere else on the alkyl backbone (i.e., detected by a5’C NMR chemical shift at about 19.54 to about 19.96 ppm). In one embodiment, OTL oil base stocks may comprise 1 .5 or more P-Me groups per molecule (e.g., >2, or from about 1.5 to about 6 P-Me groups per molecule, including all number values and subsets therebetween). In one embodiment, OTL oil base stocks may comprise about 6 mol To P-Me groups.

[0049] OTL oil base stocks may comprise various numbers of alpha carbons (“a-C”) (Le.„ a terminal free carbon at the end of an alkyl chain of length > 3, also referred to herein as alpha methyl (“cz-methyl” or “ct-Me”) groups). In one embodiment, the number of a-C per molecule is determined by detection of aL'C NMR chemical shift at about 13.92 to about 14.33 ppm, In one embodiment, OTL. oil base stocks may comprise about 1 to about 3 a~C.hnolecule, including all number values and subsets therebetween (e.g., from about 1.5 to about 2.5 a-G molecule). In one embodiment, OTL oil base stocks may comprise from about 1.7 mol% to about 2.1 mol% a-C, including all mol% a-C values and subsets therebetween. In an embodiment. OTL oil base stocks may comprise various molar ratios of P-Me groups to a -C (z.e. , a-Me groups). In an embodiment, OTL oil base stocks may comprise a molar ratio P-Me groups to a-Me groups of from about 1.2 / 1 to about 5.4 / 1 , including all values and subset therebetween (c.g. , from about 1.2 / 1 to about 3.6, or from about 2.9 / 1 to about 3.58).

[0050] Molar R atio of Epsilon Carbons (g~C) to Methyl Branches

[0051] OTL. oil base stocks may comprise various numbers of methyl branches. In one embodiment, the number of methyl branches per molecule is the sum of the number of 3-Me groups, the number of P-Me groups, and 0.5 x the number of 2-Me groups. As used herein, the term “3-Me groups”, and grammatical variations thereof refer generally to P-Me groups on carbondetected by a!3C NMR chemical shift at about 19.10 to about 19.53 ppm). As used herein, the term “2-Me groups”, and grammatical variations thereof, refer generally to P-Me groups and terminal methyl groups (“T- Me”) groups on carbon 2, also referred to herein as “P-Me / T-Me” (i.e., detected by aHC NMR chemical shift at about 22.63 to about 22 / 73 ppm).

[0052] OTL oil base stocks may comprise various numbers of epsilon carbons (“g-C”) (i.e., a methylene carbon that is more than four (4) carbons from a terminus or more than three (3) carbons from a branch). In one embodiment, the number of s-C per molecule is determined by detection of a! 3C NMR chemical shift at about 29 ppm to about 30 ppm. In one embodiment, OTL. oil base stocksmay comprise from about 6 to about 10 g-C / molecule, including all number values and subsets therebetween (eg., from about 8 to about 10 g-C molecule). In one embodiment, OTL oil base stocks may comprise from about 8 mol% E-C to about 10 mol% £-C, including ail mol% g-C values and subsets therebetween. OTL oil base stocks may comprise various molar ratios of e-C to methyl branches. In an embodiment, OTL oil base stocks may comprise a molar ratio of E-C to methyl branches of from about 0,92 to about 1.4 1, including all ratio values and subsets therebetween (e.g., from about 1.18 / 1 to about 1.36 / 1).

[0053] Branching of OTL oil base stocks as determined by FT-ICR MS

[0054] Branching properties of OTL oil base stocks may be further distinguished from typical oil base stocks, as determined by FT-ICR MS. FT-ICR MS shows differences in peak spacing between different oil base stocks, which indicates differences in degree of branching and branch size. In an embodiment, FT-ICR MS peak spacing of OTL oil base stocks is distinguishable from FT-ICR MS peak spacing of PAO. GTL, CTL, and / or EAO oil base stocks. In one embodiment, OTL oil base stocks may exhibit a distinct spacing of about 28 between each peak, as compared io traditional oil base stocks, e.g., PAO-based oil base stocks, which exhibit a spacing of 56, and EAO-based oil base stocks (e.g., Lucant HC-100) which exhibit a spacing of 14.

[0055] Rheological Properties of OTL Oil Base Stocks

[0056] OTL. oil base stocks of the present disclosure may have various rheological properties. OTL. oil base stocks of the present disclosure may have various kinematic viscosity values. .As used herein, the term “kinematic viscosity'’, and grammatical variations thereof, refer general ly to the ratio of the dynamic viscosity to the density of a material at the same temperature and pressure. Kinematic viscosity (“KV”) is measured at a defined temperature by ASTM D445 or ASTM D7279 or ASTM D7042. Shorthand terms lor kinematic viscosity at commonly used defined temperatures are KV 100 (e.g., 100 ( ") and KV40 (e.g., 40°C).

[0057] OTL oil base stocks of the present disclosure may have various K.V40 values, hi one embodiment, OTL oil base stocks may have a KV40 value of from about 10 centistokes (“cSt”) to about 1200 cSt, including all cSt values and subsets therebetween (e.g., from about 15 cSt to about 150 cSt. from about 25 cSt to about 1 1.75 cSt, from about 40 cSt to about 1 150 cSt, from about 60 cSt to about 1 100 cSt, from about 80 cSt to about 800 eSt, from about 100 cSt to about 700 cSt, or from about 40 cSt to about 500 eSt). OFF. oil base stocks of the present disclosure may have various KV 100 values. In one embodiment, OTL. oil base stocks may have a KA 100 value of from about 4 cSt to about 800 eSt. including all cSt values and subsets therebetween (e.g., from about 5 cSt to about 700cSt, from about 10 cSt to about 600 eSt from about 15 cSt to about 500 cSt, from about 20 cSt to about 400 cSt, from about 25 cSt to about 300 eSt, from about 50 cSt to about 100 cSt, from about 100 cSt to about 500 cSt, or about 4 cSt to about 50 cSt).

[0058] OTL oil base stocks of the present disclosure may have various viscosity index values. As used herein, the term “viscosity index”, and grammatical variations thereof, refer generally to an empirical, unit-less number indicating the effect of temperature change on the kinematic viscosity of the base oi l or lubricant. A higher viscosity index indicates a smaller decrease in kinematic viscosity with increasing temperature. OTL oil base stocks may have a viscosity index (“VI”) value as determined by ASTM D2270. In one embodiment, OTL oil base stocks may have a VI value o f from 130 to 190, including all VI values and subsets therebetween (eg., from about 130 to about 170, or from about 135 to about 185).

[0059] OTL oil base stocks of the present disclosure may have various pour point values. As used herein, the term “pour point”, and grammatical variations thereof, as used herein, refers to the temperature at which an oil becomes semi-solid and loses its flow characteristics. OTL oil base stocks may have a pour point as determined by IP 15 or ASTM D97 or ASTM D7345. In one embodiment, OTL oil base stocks may have a pour point value of from about -80°C to -20"C, including all °C values and subsets therebetween (eg., from about -60°C to about -25°C, from about -55PC to about -30°C, from about -50°C to about -35°C, or from about -45°C to about -40°C). In one embodiment, OTL oil base stocks may have lower pour points, as compared to typical oil base stocks having the same viscosity (e.g., KV40 or KV1.00) values, including but not limited to PAO oil base stocks, GTL oil base stocks, LAO oil base stocks, and the like.

[0060] OTL oil base stocks of the present disclosure may have various traction coefficients. As used herein, the terms “coefficient of traction”, “traction coefficient”, and grammatical variations thereof, as used herein, refer to the shearing or tangential force required to move a load, divided by the load. The traction coefficient expresses the ease with which an oil base stock, base oil, or lubricant film is sheared. OTL oil base stocks may have a traction coefficient as determined by Mini-Traction Machine (MTM) (e.g,, a ball-on-disk tribological machine from PCS Instruments, comprising a smooth ANSI 52100 steel disk and a % inch ANSI 52100 steel ball rotating under prescribed speed, temperature, load and slide-rol l ratio (SRR), where a lower coefficient of traction is indicative of lower friction). MTM testing may be performed from 0% to 100% SRR. OTL oil base stocks may have a maximum traction coefficient of from about 0.010 to 0.040, including all values and subsets therebetween (r y, from about 0.0125 to about 0.035, or from about 0.015 to about 0.030), determined using an MTM(e. g., PCS Instruments) at a slide-roll ratio (SRR ) of 100%, at a temperature of 80°C, at a speed of 2 meters, second (m / s), and wider a load of 1 gigapascal (CP). OTL oil base stocks may have lower coefficients of traction, as determined using an MTM apparatus under a given set of conditions as described above, as compared to typical oil base stocks having equivalent kinematic viscosity (e.g., KV40 or KV.100) values, such as PAO oil base stocks, GTL base stocks, EAO oil base stocks, or the like.

[0061] Stability Properties of Oil.. Oil Base Stocks

[0062] OTL oil base stocks of the present disclosure may have various thermal stability properties. In one embodiment, OTL oil base stocks of the present disclosure may have various volatility values. As used herein, the term “volatility”, and grammatical variations thereof, refer generally to how readily an oil base stock, base oil, or lubricant vaporizes. In one embodiment, OTL oil base stocks may have a Noack % volatiles value as determined by ASTM D6375 (e.g. , performed using thermogravi metric analysis (“TGA”), also referred to herein as a TGA Noack %Off value), OTL oil base stocks may have a Noack % volatiles value of from about 0.5% volatiles to about .10% volatiles, including all % volatiles values and subsets therebetween.

[0063] OTL oil base stocks may have various thermo-oxidative or oxidative stability values. The terms “'Thermo-Oxidative Stability”, “Oxidative Stability”, and grammatical variations thereof as used herein, refer to the resistance of an oil base stock, base oil, or lubricant to react with oxygen, which can degrade the oil and contribute to varnish, deposits, and poor machine performance. Oxidative stability can be measured by a number of oxidation tests, including pressurized differential scanning calorimeter (“PDSC”, CEC L-85-T-99, or ASTM D6.186) and Rotating Pressure Vessel Oxidation Test (“RPVOT” or ASTM D2272), which each blend the oil base stock with 0.5 wt.% of an aminic antioxidant (c.g., Irganox 1.57), or ExxonMobil B I O oxidative test (c.g., see US4981492). In one embodiment, OTL oil base stocks may have a RPVOT time (minutes (min) until the oxygen pressure of the oil drops by a set amount, (e g., 25 psi) of from about 170 to about 600 (min), including all min values and subsets therebetween (eg., from about 175 to about 350 min). In one embodiment, OTL oil base stocks may have a DSC oxidative induction temperature °C of from about 200°C to about 250°C, including all °C values and subsets therebetween (e,g„ from about 210°C to about 240°C). In one embodiment OTL oil base stocks may have a B10 % viscosity increase of from about 0% to less than about 10%, including all % values and subsets therebetween (e.g., from about 0.5% to about 9.5%).

[0064] In one embodiment, OTL oil base stocks may have a KVI00 % loss value of from about zero % (0%) to about 45%, including all % values and subsets therebetween (e.g., about 0%), as determined by RPVOT Oxidative stability (ASTM D2272) or by KRL20 Shear Stability Test (CEC L-45-AA-99, performed for 20 hours). Oxidative stability of OTL oil base stocks may be measured by change in total acid number (TAN). An OTL oil base stock may have a change in 'LAN after RPVOT oxidation testing as determined by ASTM D-664, ASTM D-974, ASTM D-1534, or ASTM D-3339. In one embodiment, OTL oil base stocks may have a total acid number after RPVOT testing of from about 5 mg KOH / g to about 10 mg KOH / g, including all mg KOH / g values and subsets therebetween.

[0065] (Co-Oil Base Stocks for Base Oils of Circulating Oil Formulations

[0066] The base oils of circulating oil formulations of the present disclosure comprise a co-oil base stock. The co-oil base stock used in base oil formulations of the present disclosure may comprise one single co-oil base stock or two or more different co-oil base stocks. Co-oil base stocks for use in the circulating oils may be fluids selected from API designated Group I co-oil base stocks. Group II / I1+ co-oil base stocks, Group III / III+ co-oil base stocks. Group IV co-oil base stocks, Group V co-oil base stocks, or the like, or any combination thereof Co-oil base stocks may include, but are not limited to, unrefined or refined crude oils, terpenes, mineral oils, synthetic hydrocarbons, naphthalenes, esters, the like, or any combination thereof.

[0067] Group I co-oil base stocks may comprise CORE™ series (ExxonMobil, Texas) (e.g., CORE™ 100, CORE™ 150, CORE™ 600, and CORE™ 2500). Group 11 / 11 + co-oil base stocks may comprise viscosity grade classifications of light neutral, medium neutral, or heavy neutral. Examples of suitable commercially available light neutral and medium neutral Group II.11+ co-oil base stocks include, but are not limited to the EMC™ series (ExxonMobil, Texas) (e.g., EHC™ 45, EMC™ 50, EHC™ 65, and EMC™ 110), Ultra-S* 2 (60 Neutral) (S-Oil), and the like. An example of a suitable commercially available heavy neutral Group 11 / 11+ co-oil includes, but is not limited to, EHC 340 MAX™ ( ExxonMobil, Texas), and the like. Base oi l formulations of the present disclosure, due to the use of Group II heavy neutrals, may allow for increased performance similar to or exceeding performance standards of base oils formulated with solely Group IV base stocks (e.g, PAOs) while having lower cost and not requiring a higher wt.% of thickener.

[0068] T he Group III 111+ co-oil base stocks for use in the base oil formulations of the present disclosure may include, but are not limited to, CTLs, GTLs, the like, and any combination thereof. An example of a suitable commercially available Group I II I II+- co-oil base stock includes, but is notlimited to, the Visom! Mseries (Exxon.Mobil,UK) (e.g., Visom™ 4 and Visom™ 6), the Qatar GTL QHVI series (Shell Oil) (e.g., Qatar GTL QHVI 4 (e.g., GTL 4), Qatar GTL QHVI 8 (e.g., GTL 8), and the like.(0069] T he Group IV co-oil base stocks for use in the circulating oil formulations of the present disclosure may include various PAOs. PAOs for use in the base oil fonnulations are not considered to be particularly limited. PAOs may include, for example, typical PAOs ( light or heavy), metallocene PAOs (mPAOs), the like, and any combination thereof Examples of suitable commercially available typical PAO co-oil base stocks include, but are not limited to, the SpectraSyn series PAOs (Exxon Mobil Chemical) (e.g., SpectraSyn™ 2, SpectraSyn™ 2C, SpectraSyn™ 4, SpectraSyn™ 5, SpectraSyn ’M6 (e.g., PAO 6), SpectraSyn™ 8, SpectraSyn 10, SpectraSyn™ 40 (e.g., PAO 40), and SpectraSyn™ 100 (e.g., PAO 100)). Examples of a suitable commercially available metallocene PAOs (mPAOs) include, but are not limited to, the SpectraSyn Elite series mPAOs (ExxonMobil Chemical) (e.g., SpectraSyn™ Elite 65, SpectraSyn ™ Elite 150, and SpectraSyn™ Elite 300), the Durasyrf* series (e.g., DurasytV 180R (e.g, mPAO 100)).

[0070] As described above, the co-oil base stock may additionally function as a Trim Stock. Examples of suitable Trim Stocks may include any low viscosity (“LS”) Group II-1V oil base stocks including, but not limited to, a light neutral or medium neutral Group II / IR oil base stock, a low viscosity PAO (e.g., PAO 6, PAO 4) oil base stock, a low' viscosity gas-to-liquids (GTL) oil base stock (e.g., GTL 4, GTL 8), and the like, and any combination thereof. Examples of suitable commercially available trim stocks for use in the present disclosure include, but are not limited to, EHC™ 50, Ultra-S^' 2 (60 Neutral) (S-Oil), SpectraSyn™ 6 or SpectraSyn™ 4, Qatar GTL. QHVI 4 (Shell Oil), or Qatar GTL QHVI 8 (Shell Oil).

[0071] G roup V co-oil base stocks for use in the base oil fonnulations of the present disclosure may include, but. are not limited to, an ester (including esters of a dibasic acid (e.g., phthalic, succinic, alkylsuccinic, alkenylsuccinic, maleic, azelaic, suberic, sebacic, fumaric or adipic acid (adipate), or iinolic acid dimmer) and alcohol (e.g., butyl, hexyl, 2-ethylhexyI, dodecyl alcohol, ethylene glycol, diethylene glycol monoether or propylene glycol), and esters of a monocarboxylic acid of 5 to 18 carbon atoms and polyol (e.g.. neopentyl glycol, trimethylolpropane (TMP), pentaerythritol, dipentaerythritol or tripentaerythritol)); a naphthalene compound (e.g, an alkylated naphthalene): polyoxyalkylene glycols (PAGs), esters thereof, and ethers thereof; phosphate esters, the like, and any combination thereof. In particular embodiments, the Group V co-oil base stocks may comprise a TMP ester, an adipate ester, an alkylated naphthalene, a PAG, and any combination thereof. Examplesof suitable Group V co-oil base stocks include, but are not limited to, adipate esters (e.g., ditridecyl adipate, diisodecyl adipate, e.g., Esterex, Mseries, ExxonMobil Chemical) and alkylated naphthalene (e.g., Synessticl Mseries, ExxonMobil Chemical). When included, the Group V co-oil base stock may be in an amount of from about 1 wt.% to about 30 wt.%, including all wt.% values and subsets therein (e.g., 2 wt.% to 25 wt.%), by total weight of the circulating oil formulation.

[0072] Rheological Properties of Co-Oil Base Stocks|0073] Suitable co-oil base stocks for the base oil formulations of the present disclosure may have various rheological properties, as determined by any of the rheological testing methods suitable for OTL oil base stocks. In one embodiment, a co-oil base stock has a KV40 of from about 1 cSt to about 2000 cSt, including al l eSt values and subsets therebetween. In one embodiment, a co-oil base stock may have a KV100 of from about 0.1 cSt to about 300 cSt, including all cSt values and subsets therebetween. In one embodiment, a co-oil base stock may have a VI of from 60 to 300, including all viscosity index values and subsets therebetween. In one embodiment, a co-oil base stock may have a pour point of from about -60°C to -20°C, including all °C values and subsets therebetween.

[0074] Suitable co-oil base stocks of the present disclosure may have various pour points. In one embodiment, a co-oil base stock may have a pour point value of from about -80°C to -2()°C, including allQC values and subsets therebetween (e.g., from about -60°C to about -25PC, from about -50°C to about -3()'3C, from about -40°C to about -35*0).

[0075] Suitable co-oil base stocks of the present disclosure may have various traction coefficients. In one embodiment, a co-oil base stock may have a maximum traction coefficient of from about 0.02 to 0.03, including all values and subsets therebetween, determined using an MTM (e.g., PCS Instruments) at a slide-roll ratio (SRR) of 30% to 100%, at a temperature of 40°C to 80°C, al a speed of about 2 meters second (m / s), and under a load of about I gigapascal (GP).

[0076] Stability Properties of Co-Oil Base Stocks

[0077] Suitable co-oil base stocks of the present disclosure may have various thermal stability properties, as determined by any one of the thermal stability test methods suitable for OTL oil base stocks. A co-oil base stock may have various volatility values. In one embodiment, a co-oil base stock may have a Noack % volatiles value of from about 0.5% volatiles to about 10% volatiles, including all % volatiles values and subsets therebetween.

[0078] Suitable co-oil base stocks of the present disclosure may have various thermo-oxidative or oxidative stability values, as determined by any one of the thermo-oxidative or oxidative stability tests suitable for OTL oil base stocks. In one embodiment, a co-oil base stock may have an RPVOTtime of from about 170 to about 600 min, including ail min values and subsets therebetween. In one embodiment, a co-oil base stock may have a DSC oxidative induction temperature (°C) of from about 200°C to about 250°C, including all °C values and subsets. In one embodiment; OTL oil base stocks may have a B 10 % viscosity increase of from about 0% to less than about 10%, including all % values and subsets therebetween.

[0079] Suitable co-oil base stocks of the present disclosure may have various shear stability values, as determined by any one of the shear stability test methods suitable for OTL base oil stocks. In one embodiment, a co-oil base stock may have a KV 100 % loss value of from about zero % (0%) to about 45%, including all % values and subsets therebetween (eg., about 0%). In one embodiment, a co-oil base stock may have a TAN after RP VOT of from about 5 to about 10 mg KOFI / g, including all nig KOH g values and subsets therebetween.

[0080] Additives for Circulating Oil Formulations

[0081] The circulating oil formulations of the present disclosure may comprise one or more additives (e.g., additives related to solubility, friction, oxidation stability, cleanliness, defoaming, viscosity, the like, and any combination thereof to satisfy diversified characteristics), hi one embodiment, the one or more additives may be a performance additive package included in the circulating oil formulation from 0.05 wt.% to 10 wt.%, including all wt.% values and subsets therebetween from about 0.1 wt.% to about 8 wt.%, from about 0.5 wt.% to about 5 wt.%, from about 1 wt.% to about 3 wt.%, from about 1.5 wt.% to about 2 wt.%, or from about 3 wt.% to about 10 wt.%), based on the total weight of the circulating oil formulation.

[0082] The additives for use in the circulating oil formulations may comprise a wear inhibitor, a friction modifier, a corrosion inhibitor, a detergent, a dispersant, a viscosity index improver, a pour point improver, an anti-oxidant, a defoamer, a demulsifier, the like, and any combination thereof. The additives for use in the circulating oil formulations may be zinc-containing, zinc-free, or ash-free.[0083| The dispersant may be an ashless dispersant. Ashless dispersants may include, but are not limited to, those based on polybutenyl succinic acid imide, polybutenyl succinic acid amide, benzylamine, succinic acid ester, succinic acid ester-amide and a boron derivative thereof, the like, and any combination thereof. The pour point improver may be a pour point depressant. Pour point depressants may include, but are not limited to, ethylene vinyl acetate copolymer, condensate of chlorinated paraffin and naphthalene, condensate of chlorinated paraffin and phenol, polymethacrylate, polyalkyl styrene, the like, and any combination thereof. The defoamer may include, but is not limited to, dimethyl polysiloxane, polyacrylate and a fluorine derivative thereof,poerfluoropolyether, the like, and any combination thereof. The antioxidant for use in the circulating oil formulations of the present invention may include, but is not limited to, amine-based antioxidants (e.g„ alkylated di phenyl amine, phenyl-a-naphthylamine and alkylated phenyl-x-naphthylamine); phenol-based antioxidants (e.g, 4,4'-methylenebis-(2,6-di-t-buty1pheno1), 2,6-di-t-butyl phenol, and isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyI)propionate); sulfur-based antioxidants (e.g„ dilauryl- 3,3 '-thiodipropionate); zinc dithiophosphate, the like, and any combination thereof. The corrosion inhibitor may include, but is not limited to, a fatty acid, alkenyl succinic acid half ester, fatty acid soap, alkylsulfonate, polyhydric alcohol fatty acid ester, fatty acid amine, oxidized paraffin, and alkylpolyoxyethylene ether, the like, and any combination thereof. The corrosion inhibitor may be a metal passivator. The friction modifier may include, but is not limited to, an organomolybdenum- based compound, fatty acid, higher alcohol, fatty acid ester, oil / fat, amine, polyamide, sulfide ester, phosphoric acid ester, acid phosphoric acid ester, acid phosphorous acid ester, amine salt of phosphoric acid ester, the like, and any combination thereof,

[0084] In an embodiment, the viscosity index improver may include, but is not limited to, polyisobutylene (PIB), polymethacrylate (PMA) (eg., polyalkylmethacrylates), olefin copolymers (OOP) (ftg., ethylene-propylene copolymers, ethylene-propylene diene-modifled copolymers (EPDMs), and the like), styrene maleic anhydride ester copolymers (Styrene Esters), hydrogenated styrene diene (USD) copolymers (e.g., styrene-ethylene.’’butylene-styrene copolymer (SEES), styrene-isoprene, and the like ), radial isoprene polymers / copolymers, the like, and any combination thereof. An example of a suitable commercially available viscosity index improver includes, but is not limited to, Viscoplex® 8-219 (Evonik). In an embodiment, a circulating oil formulation comprises a viscosity index improver as part of an additive performance package, hi an embodiment, a circulating oil formulation comprises a viscosity index improver in addition to an additive performance package (e.g., a co-oil base stock may comprise the viscosity index improver).

[0085] C i rcu lat i n g O i l Formu lat ions

[0086] In certain embodiments, circulating oil formulations of the present disclosure are formed by mixing the various components of the various base oil stocks and the additives according to one or more methods of the present disclosure. In certain embodiments, the mixture may be heated, such as in a reaction vessel. In certain embodiments, the mixture may be homogenized to ensure well- mixed and evenly dispersed components. If heated, the mixture is cooled after homogenization.

[0087] Further, in one or more embodiments, at least the OI L oil base stock and the co-oil base stock of the various base oils of the present disclosure are pre-blended. Moreover, two or more pre-blends may be themselves blended to achieve a lower viscosity index and a lower kinematic viscosity (40 C and 100'3C) base oil compared to either of the pre-blends alone. It is to be noted, that alternatively, at least the OTL oil base stock and the co-oil base stock may be pre-blended without blending with additional pre-blends.

[0088] T he circulating oil formulations of the present disclosure may be competitive with or superior to P AO-based, CTL-based, GTL-based, or EAO-based circulating oil formulations in one or more performance properties (e.g., coefficient of traction, oxidation stability, shear stability, or the like).

[0089] Ci rculating Qi I Formulation Rheological Properties

[0090] T he circulating oil formulations may have various rheological properties, as determined by any one of the rheological test methods suitable for OIL oil base stocks. The circulating oil formulations may have a KV40 value of from about 10 cSt to about 600 cSt, including all cSt values and subsets therebetween (e.g., from about 15 cSt to about 150 cSt, from about 100 to about 600 cSt, from about 120 cSt to about 550 cSt, from about 150 cSt to about 500 cSt, from about 200 cSt to about 300 eSt, from about 300 cSt to about 400 cSt, or from about 400 cSt to about 500 cSt). The circulating oil formulations may have a KV 100 value of from about 10 cSt to about 70 cSt, including all cSt values and subsets therebetween (e.g., from about 15 cSt to about 60 cSt, from about 20 eSt to about 50 cSt, or from about 25 cSt to about 40 cSt). The circulating oil formulations may have a VI of from about 120 to about 180, including all values and subsets therebetween (e.g., from about 120 to about 130, from about 140 to about 160, from about 160 to about 180, or from about 160 to about 170). The circulating oil formulations may have a pour point of from about -50°C to about -20°C, including all °C values and subsets therebetween (e.g., from about -45 °C to about -30°C, or from about -45°C to about -39°C).

[0091] The circulating oil formulations of the present disclosure may have various traction coefficients. In one embodiment, circulating oil formulations may have <t maximum traction coefficient of from about 0.02 to 0.03, including all values and subsets therebetween.

[0092] Circulating Oil Formulation Thermal Stability Properties

[0093] Suitable circulating oil formulations of the present disclosure may have various thermal stability properties, as determined by any one of the thermal stability test methods suitable for OTL oil base stocks. Circulating oil formulations may have various volatility values. In one embodiment, circulating oil formulations may have a Noack % volatiles value of from about 0.5% volatiles to about 10% volatiles, including all % volatiles values and subsets therebetween.

[0094] Circulating Oil Formulation Oxidative Stability Properties

[0095] Suitable circulating oil formulations of the present disclosure may have various thermo- oxidative or oxidative stability values, as determined by any one of the thermo-oxidative or oxidative stability tests suitable for OTL oil base stocks. In one embodiment, circulating oil formulations may have a BIO % viscosity increase of from about 0% to less than about 10%, including all % values and subsets therebetween (e.g., about 9.5% or less, about 9.0% or less, or about 8.5% or less).

[0096] Suitable circulating oil formulations of the present disclosure may have various shear stability values, as determined by any one of the shear stability test methods suitable for OTL base oil stocks. In one embodiment, a circulating oil formulations may have a KV100 % loss value of from about zero % (0%) to about 45'%, inchiding all % values and subsets therebetween (e.g., about 0%). In one embodiment, a co-oil base stock may have a TAN after RPVOT of from about 5 to about 10 mg KOH g. including all mg KOH g values and subsets therebetween.

[0097] To facilitate a better understanding of the embodiments of the present invention, the following examples of preferred or representative embodiments are given. In no way should the following examples be read to limit, or to define, the scope of the invention.Example .Embodiments

[0098] Embodiments include:

[0099] A: Circulating oil compositions. The circulating oil compositions comprise: a base oil and a performance additive package, wherein the base oil comprises at least a first oil base stock and a second doil base stock: wherein the first oil base stock is an OTL oil base stock having a molar ratio of pendant methyl groups to a-methyl groups of from 1.2 / 1 to 5.4 / 1, as determined by carbon 13 nuclear magnetic resonance spectroscopy (UCN MR); and wherein the second oil base stock comprises one or more Group I, Group II, Group 11+, Group III, Group Ill h Group IV, or Group V oil base stocks, or any combination thereof.

[0100] B: Circulating Oil Methods. The circulating oil methods comprise: providing a base oil for a circulating oil composition, the base oil comprising at least a first oil base stock and a second oil base stock, wherein providing the base oil optionally comprises blending the first oil base stock with the second oil base stock; optionally, blending the base oil with a performance additive package, thereby forming the circulating oil composition; wherein the first oil base stock is an OTL oil base stock having: a molar ratio of pendant methyl groups to a-methyl groups of from 1.2 / 1 to 5.4 1, as determined by carbon 13 nuclear magnetic resonance spectroscopy (LKNMR); and wherein thesecond oil base stock comprises one or more Group I, Group II, Group 1I+, Group III, Group III+, or Group IV, Group V oil base stocks, or any combination thereof.

[0101] Each of Embodiments A and B may have one or more of the following additional elements in any combination:

[0102] Element 1; wherein the first oil base stock is an OTL oil base stock having a molar ratio of epsilon carbons (s-C) to methyl branches of from 0.92 / 1 to 1.4 / 1, as determined byBCNMR.|0103| Element 2: wherein the first oil base stock is an OTL oil base stock having: a molar ratio of total methyl groups to short chain methyl groups of from 1.1 / 1 to 1.8 / 1 , as determined by proton nuclear magnetic resonance spectroscopy (HNMR); and / or a molar ratio of total methylene and methine groups to total methyl groups of from 2 1 to 4.5 / 1 , as determined byHNMR.

[0104] Element 3: wherein the OTL oil base stock has a lower number average molecular weight (M«), weight-average molecular weight (Mw), z-average molecular weight (XL), and / or polydispersity, as determined by GPC analysis, as compared to a polyalphaolefin (PAO) or a gas-to- hquid (GTE.) oil base stock having an equivalent kinematic viscosity at 100°C (KV100), as determined by AS I'M D445 or D7279, to the OTL oil base stock.

[0105] Element 4: wherein the OTL oil base stock has: a kinematic viscosity at 40°C (KV40), as determined by A STM 0445 or ASTM D7279 or A STM D7042, of from 60 to 1100; a kinematic viscosity at 100°C (KVIOO), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 10 to 100; a viscosity index, as determined by ASTM D2270, of from 145 to 200; a pour point, as determined by IP 15 or ASTM D97 or ASTM D7345 of -60°C to -40°C; a KV 100 % loss, as determined by CEC L-45-AA-99, of zero % (0%); and / or a coefficient of traction, as determined by Mini -Traction Machine, at a slide-roll ratio (SRR) of from 40% to 1.00%, and at a temperature of from 40°C to 100°C, of from 0.010 to 0.040.10.106] Element 5: wherein the OTL oil base stock is present at from 30 wt.% to 99 wt.%, based on the total weight of the base oil; and / or wherein the second oil base stock is present at from 1 wt.% to 70 wt.%. based on the total weight of the base oil.

[0107] Element 6: wherein the second oil base stock comprises one or more Group 11-1 V oil base stocks, and wherein the second oil base stock has: a lower kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or ASTM D7279 or A STM D7042; a lower kinematic viscosity at 100°C (KV100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042; and / or a lower viscosity index, as determined by ASTM D2270; as compared to the OTL oil base stock.

[0108] Element 7: wherein the circulating oil composition comprises a viscosity index improver; and or wherein the second oil base stock comprises a Group V oil base stock comprising one or more of the group consisting of an ester, a naphthalene compound, a polyoxyalkylene glycol (PAG), an ester thereof an ether thereof, a phosphate, and any combination thereof

[0109] Element 8: wherein the circulating oil composition has: a higher viscosity index, as determined by ASTM D2270; a lower B10 viscosity % increase, as determined by ExxonMobil BIO oxidation test; and or a lower coefficient of traction, as determined by Mini-Traction Machine, under a constant, speed, temperature, load, and slide-roil ratio (SRR); as compared to a circulating oil composition comprising, as the first oil base stock of the base oil composition, a polyalphaolefin ( TAO) oil base stock, a gas-to-liquid (GTL) oil base stock, or an ethylene-alpha-olefin copolymer (EAO) oil base stock having an equivalent kinematic viscosity at 100°C (K.V100), as determined by ASTM 13445 or D7279, to the OI L oil base stock.

[0110] Element 9: wherein the circulating oil composition has: a kinematic viscosity at 4O’*’C (KV40), as determined by ASTM D445 or ASTM D7279 or ASTM 1)7042, of from 200 cSt to 300 cSt; a kinematic viscosity at 100°C (KV100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 25 cSt to 35 cSt; a viscosity index, as determined by ASTM D2270, of from 140 to 180; a B 10 viscosity % increase, as determined by ExxonMobil B10 oxidation test, of 10° T or less; and / or a coefficient of traction, as determined by Mini-Traction Machine, at a slide-roll ratio (SRR) of from 40% to 100%, and at a temperature offrom 4(LC to 10(fJC, of 0.010 to 0.040.

[0111] Element 10: wherein the performance additive package is present at from 0.5 wt.% to 5 wt.%, based on the total weight of the circulating oil composition.

[0112] Element 11: wherein the performance additive package comprises one or more of a group consisting of antioxidants, antiwear agents, detergents, antifoaming agents, demulsifier agents, viscosity index improvers, and metal passivators, and any combination thereof

[0113] By way of non-limiting example, exemplary combinations applicable to Embodiments A and B include: any one, more, or all of Elements 1-1 1, without limitation.

[0114] The present disclosure is further directed to the following non-limiting embodiments.

[0115] Embodiment 1. A circulating oil composition comprising a base oil and a performance additive package, wherein the base oil comprises at least a first oil base stock and a second oil base stock: wherein the first oil base stock is an Oil. oil base stock having a molar ratio of pendant methyl groups to a-methyl groups of from 1.2 / 1 to 5.4 I , as determined by carbon 13 nuclear magnetic resonance spectroscopy (i UNMR); and wherein the second oil base stock comprises one or moreGroup I, Group II, Group 11% Group ITT, Group III+, Group IV. or Group V oil base stocks, or any combination thereof.

[0116] Embodiment 2. The circulating oil composition of Embodiment I , wherein the first oil base stock is an. OTL oil base stock having a molar ratio of epsilon carbons (K-C) to methyl branches of from 0.92 / 1 to 1.4 / 1, as determined by1<CNMR.

[0117] Embodiment 3. The circulating oil composition of Embodiment 1 or Embodiment 2, wherein the first oil base stock is an OTL oil base stock having: a molar ratio of total methyl groups to short chain methyl groups of from 1.1 / 1 to 1.8 / 1, as determined by proton nuclear magnetic resonance spectroscopy (HNrMR); and / or a molar ratio of total methylene and methine groups to total methyl groups of from 2 '1 to 4.5 / 1, as de termi ned byHNMR.

[0118] Embodiment 4. Ebe circulating oil composition of any one of Embodiments 1-3, wherein the OTL oil base stock has a lower number average molecular weight (Mn), weight-average molecular weight (Mw), z-average molecular weight (Mz), and / or polydispersity, as determined by gel permeation chromatography (GPC ), as compared to a polyalphaolefin (P AO) or a gas-to-liquid (GTL) oil base stock having an equivalent kinematic viscosity at 100°C (KV100), as determined by ASTM D445 or D7279, to the OTL oil base slock.

[0119] Embodiment 5. The circulating oil composition of any one of Embodiments 1-4, wherein the OTL oil base stock has; a kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 60 to 1100; a kinematic viscosity at 100°C (KV100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 10 to 100; a viscosity index, as determined by ASTM D2270, of from 145 to 200; a pour point, as determined by IP 15 or ASTM D97 or ASTM D7345 of -60°C to -40°C; a KV100 % loss, as determined by CEC L-45-AA-99, of zero % (0%); and / or a coefficient of traction, as determined by Mini-Traction Machine, at a slide-roll ratio (SRR) of from 40% to 100%, and at a temperature of from 40°C to 100°C, of from 0.010 to 0.040.

[0120] Embodiment 6. The circulating oil composition of any one of Embodiments 1-5, wherein the OTL oil base stock is present at from 30 wt.% to 99 wt.%, based on the total weight of the base oil; and / or wherein the second oil base stock is present at from 1 wt.% to 70 wt.%, based on the total weight of the base oil.[0121 | Embodiment 7. The circulating oil composition of any one of Embodiments 1-6, wherein the second oil base stock comprises one or more Group 11-IV oil base stocks, and wherein the second oil base stock lias: a lower kinematic viscosity at 40°C (K.V40), as determined by ASTM D445 orASTM D7279 or ASTM D7042; a lower kinematic viscosity at 100°C (KVIOO), as determined by ASTM D445 or ASTM D7279 or ASTM D7042; and / or a lower viscosity index, as determined by ASTM D2270; as compared to the OTL oil base stock.

[0122] Embodiment 8. The circulating oil composition of any one of Embodients 1-7, wherein the circulating oil composition comprises a viscosity index improver; and / or wherein the second oil base stock comprises a Group V oil base stock comprising one or more of the group consisting of an ester, a naphthalene compound, a polyoxyalkylene glycol (PAG), an ester thereof, an ether thereof, a phosphate, and any combination thereof.

[0123] Embodiment 9, The circulating oil composition of any one of Embodiments 1-8, wherein the circulating oil composition has: a higher viscosity index, as determined by ASTM D2270; a lower BIO viscosity % increase, as determined by ExxonMobil BIO oxidation test; and / or a lower coefficient of traction, as determined by Mini-Traction Machine, under a constant speed, temperature, load, and slide-roll ratio (SRR); as compared to a circulating oil composition comprising, as the first oil base stock of the base oil composition, a polyalphaolefin (IhAO) oil base stock, a gas-to-liquid (GTE) oil base stock, or an ethylene-alpha-olefin copolymer (EAO) oil base stock having an equivalent kinematic viscosity at 100°C (KAT 00), as determined by ASTM D445 or D7279, to the OTL oil base stock.

[0124] Embodiment 10. The circulating oil composition of any one of Embodiments 1-9, wherein the circulating oil composition has: a kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 200 cSt to 300 cSt; a kinematic viscosity at 100°C (KV.100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 25 cSt to 35 eSt; a viscosity index, as determined by ASTM D2270, of from 140 to 180; a B10 viscosity % increase, as determined by ExxonMobil B10 oxidation test, of 10% or less; and / or a coefficient of traction, as determined by Mini-Traction Machine, at a slide-roll ratio (SRR) of from 40% to 100%, and at a temperature of from 40°C to 100°C, of 0.010 to 0.040.

[0125] Embodiment 1 1. The circulating oil composition of any one of Embodiments 1-10, wherein the performance additive package is present at from 0.5 wt.% to 5 wt.%, based on the total weight of the circulating oil composition.

[0126] Embodiment 12. The circulating oil composition of any one of Embodiments 1-11 wherein the performance additive package comprises one or more of a group consisting of antioxidants, antiwear agents, detergents, antifoaming agents, demulsifier agents, viscosity index improvers, and metal passivators, and any combination thereof.

[0127] Embodiment 13. A method for improving the energy efficiency and or the oxidation stability of a circulating oil composition, the method comprising: providing a base oil for a circulating oil composition, the base oil comprising at least a first oil base stock and a second oil base stock, wherein providing the base oil optionally comprises blending the first oil base stock with the second oil base stock; optionally, blending the base oil with a performance additive package, thereby forming the circulating oil composition; wherein the first oil base stock is an OTL oil base stock having: a molar ratio of pendant methyl groups to a-methyl groups of from 1.2 / 1 to 5.4 / 1 , as determined by carbon 13 nuclear magnetic resonance spectroscopy (13CNMR); and wherein the second oil base stock comprises one or more Group I, Group II, Group IR, Group ill, Group HR, or Group IV, Group V oil base stocks, or any combination thereof.

[0128] Embodiment 14, The method of Embodiment 13, wherein the first oil base stock is an O i l. oil base stock having a molar ratio of epsilon carbons (E-C) to methyl branches of from 0.92 / 1 to 1.4 / 1, as determined by,3CNMR.

[0129] Embodiment 15, The method of Embodiment 13 or Embodiment 14, wherein the first oil base stock is an OTL oil base stock having: a molar ratio of total methyl groups to short chain methyl groups of from 1, 1 / 1 to 1.8 / 1, as determined by proton nuclear magnetic resonance spectroscopy (HNMR.); and / or a molar ratio of total methylene and methine groups to total methy l groups of from 2 / 1 to 4.5 / 1, as determined byHNMR.

[0130] Embodiment 16. The method of any one of Embodiments 13-15, wherein the OTL oil base stock has a lower number average molecular weight (M#), weight-average molecular weight (M«). z- averagc molecular weight (NT), and / or polydispersity, as determined by gel permeation chromatography (GPC), as compared to a polyalphaolefin (PAO) or a gas-to-liquid (GTL) oil base stock having an equivalent kinematic viscosity at 100°C (KV100), as determined by ASTM D445 or 1)7279. to the OTL. oil base stock.

[0131] Embodiment 1.7. T he method of any one of Embodiments 13-16, wherein the O TL. oil base stock has: a kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 60 to 1 100; a kinematic viscosity at 100°C (KV100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 10 to 100; a viscosity index, as determined by ASTM D2270, of from 145 to 200; a pour point, as determined by IP 15 or ASTM D97 or ASTM D7345 of -60°C to -40°C; a KV100% loss, as determined by CISC L-45-AA-99, of zero % (0%); and or a coefficient of traction, as determined by Mini-Traction Machine, at a slide-roll ratio (S RR) of from 40% to 100%, and at a temperature of from 40 C to 100 C. of from 0.010 to 0.040.

[0132] Embodiment 18. The method of any one of Embodiments 13-17, wherein the OTL oil base stock is present at from 30 wt.% to 99 wt.%, based on the total weight of the base oil; and or wherein the second oil base stock is present at from 1 wt.% to 70 wt." based on the total weight of the base oil.

[0133] Embodiment 19. The method of any one of Embodiments 13-18, wherein the second oil base stock comprises one or more Group IL-1 V oil base stocks, and wherein the second oil base stock has: a lower kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or ASTM D7279 or A STM D7042; a lower kinematic viscosity at 100%' (KV100), as determined by ASTM D445 or AS TM D7279 or ASTM D7042; and / or a lower viscosity index, as determined by ASTM D2270; as compared to the OTL oil base stock.

[0134] Embodiment 20. The method of any one of Embodiments 13-19, wherein the circulating oil composition comprises a viscosity index improver; and / or wherein the second oil base stock comprises a Group V oil base stock comprising one or more of the group consisting of an ester, a naphthalene compound, a polyoxyalkylene glycol (PAG), an ester thereof, an ether thereof, a phosphate, and any combination thereof.

[0135] Embodiment 21. The method of any one of Embodiments 13-20, wherein the circulating oil composition has: a higher viscosity index, as determined by ASTM D2270; a lower BIO viscosity % increase, as determined by ExxonMobil B10 oxidation test; and or a lower coefficient of traction, as determined by Mini-Traction Machine, under a constant speed, temperature, load, and slide-roll ratio (SRR); as compared to a circulating oil composition comprising, as the first oil base stock of the base oil composition, a polyalphaolefin (PAO) oil base stock, a gas-to-liquid (GTL) oil base stock, or an ethylene-alpha-olefin copolymer (EAO) oil base stock having an equivalent kinematic viscosity at l00°C (KVI00), as determined by ASTM D445 or D7279, to the Oil., oil base stock.

[0136] Embodiment 22. The method of any one of Embodiments 13-21, wherein the circulating oil composition has: a kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or ASTM D7279 or ASTM 07042, of from 200 cSt to 300 cSt; a kinematic viscosity at 100°C (KVIOO), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 25 cSt to 35 cSt; a viscosity index, as determined by ASTM D2270, of from 140 to 180; a B 10 viscosity % increase, as determined by ExxonMobil B10 oxidation test, of 10% or less; and / or a coefficient of traction, as determined by Mini-Traction Machine, at a slide-roll ratio (SRR) of from 40% to 100%, and at a temperature of from 40°C to 100°C. of 0.010 to 0.040.

[0137] Embodiment 23. The method of any one of Embodiments 13-22, wherein the performance additive package is present at from 0.5 wt% to 5 wt.%, based on the total weight of the circulating oil composition.

[0138] Embodiment 24. The method of any one of Embodiments 13-23, wherein the performance additive package comprises one or more of a group consisting of antioxidants, antiwear agents, detergents, antifoaming agents, demulsifier agents, viscosity index improvers, and metal passivators, and any combination thereofEXAMPLESE xamp I e 1 Formu l ated H y drau I ic Oi I s

[0139] Hydraulic oils are a specific class of lubricating oils. Hydraulic oils are lubricating oils that not only require lubricating characteristics, but also the ability to transmit power through hydraulic machinery, good flow characteristics at various temperatures, as well as thermal stability, oxidative stability, and hydrolytic stability. Rheological properties of a hydraulic oil also play a critical role in reducing internal leakage in circulating systems. For a given system, the thinner a hydraulic oil is, the more easily leakage can happen. Hydraulic oil can leak through gaps within a pump, valve, seals or even the connection of pipes. Volumetric efficiency, the ratio of the actual flow rate to the theoretical flow rate based on displacement kinematics and the rotation speed, describes hew effectively a pump can move fluid around. A higher volumetric efficiency indicates less systematic leakage. Viscosity index, the rate of the viscosity change due to a temperature change, is widely considered correlated with volumetric efficiency. Given the same ISO viscosity grade, high VI oil has a higher viscosity at high temperatures, which can reduce leakage in a hydraulic system.

[0140] To improve volumetric efficiency, the most common hydraulic oil formulation strategy is to add a viscosity index improver (“VI F’), (e.g. , a polymeric viscosity index improver (“polymer VIP')). A drawback of using viscosity index improvers is the permanent shear thinning effect, which can reduce viscometric properties of in-service oil and therefore impair the energy efficiency benefit of the hydraulic oil. Restated, polymeric viscosity index improvers are sheared down in service, thus the volumetric efficiency drops significantly as a result.

[0141] Herein is reported a hydraulic oil formulation strategy using OTL oil base stocks (eg., OTL 40, having a KVl 00 - 40 cSt) with a low viscosity Group II base oil to achieve 170 VI with no shear thinning. The formulation strategy can be used to improve modeled volumetric efficiency by 3%compared to a monograde hydraulic oil which may lead to more than 11% fuel efficiency gain (e.g., in an excavator circulating system).

[0142] Table 1 compares kinematic viscosity, viscosity index, and volumetric efficiency of four (4) hydraulic oil formulations including three (3) Comparative Examples (“CEi”, “CE2”, and “CE3”) and an Inventive Example (“IE”). Note, “OTL” is also referred to herein as “ETL”.TABLE 1

[0143] A typical additive package for a hydraulic oil may contain: a wear inhibitor, a friction modifier, a corrosion inhibitor, a viscosity index improver, a pour point improver, an anti-oxidant, a defoamer, a demulsifier, the like, and any combination thereof. The package can range from 0.5 wt.% to 5 wt.%, optimally from I wt.% to 4 wt.%,

[0144] Volumetric efficiency is defined as the ratio of the actual flow to the theoretical flow, where the actual flow may be determined by a flow meter, and the theoretical flow is calculated by multiplying the pump’s displacement per revolution by its driven speed. The volumetric efficiency is modeled under two typical operational conditions. An “effective leakage diameter” is characterized using a reference fluid and is unique to the pump design. A physics-based model was used, which simulated the volumetric efficiency of a modified industry vane pump. The physics-based model wasvalidated with test data of known lubricant properties. Based on the test data validated, physics-based model, viscosity at the operating temperature (as characterized by the viscosity' index, KV40, and KV100 values) and degree of permanent shear loss (as characterized in the KRL20 Shear Stability Test, Kurt-Orbahn Shear Stability Test, or the like) were found to be the primary physical properties that impact volumetric efficiency' performance, with density and pressure-viscosity coefficient having secondary' impacts. Even though each example has a different additive level, this does not affect volumetric efficiency as this property is driven by oil base stock and VII composition. As shown in Table 1, the invention shows higher volumetric efficiency' than all three comparative examples. The invention shows 3% higher modeled volumetric efficiency than monograde hydraulic oil shown in CE2, which is estimated to provide more than 1 1% fuel efficiency improvement, based on previous high efficiency fluid development field tests. The fuel efficiency estimation is calculated based on the difference between modeled volumetric efficiency of CE1 and CE2, and the measured fuel efficiency gain due to this difference. CE3 uses synthetic base oil PAO, but the VI of this formulation ("VI— 143) is significantly lower than invention (V 1=174). 'Therefore, not all high VI synthetic base oils can achieve the same VI target as IE.

[0145] Circulating oils are a specific class of lubricating oils. Circulating oils are lubricating oils for the centralized continuous and reusable lubrication of various systems, to protect critical components such as bearings, blowers, gearboxes, or the like, for a wide range of purposes (e.g., heat exchange, friction reduction, and prevention of wear, corrosion, and rust). Circulating oils operate under conditions of high temperature, exposure to filtration operations, long oil drain intervals, and contact with moisture and other contaminants. Further, circulating oils require exceptional oil life, often tens of thousands of hours. Due to the millions of gallons of these oils used annually, circulating oils must have excellent thermal stability, oxidative stability, filterability, foaming resistance, compatibility' with multiple materials, low traction coefficient, low temperature fluidity, and high film thickness at high temperatures.

[0146] This Example provides various suitable formulations for circulation oils of the present disclosure. Table 2 compares kinematic viscosity, viscosity index, and viscosity increase after B10 of five (5) formulations including two (2) Comparative Examples (“CE1”, and “CE2”) and three (3) Inventive Examples ("‘1111”, ‘TE2”, and “IE3”). Note, “OTL” is also referred to herein as “ETL”.TABLE 2*Not Tested[0147| Improved oxidation stability can lead to longer oil life in severe oil service, 'fable 2 shows improved viscosity increase control in the ExxonMobil B I O oxidation test (already described in multiple US patents, e.g., US 4,981,492) for the inventive examples with ETL oil base stock vs. the PAO comparative examples, run at the very severe conditions of 163°C for 120 hrs. This is unexpected as PAO has exceptional oxidation stability.

[0148] The inventive example also gives improved energy efficiency (as shown by a reduced traction coefficient). FIG. 1A-1 D shows the traction coefficient as a function of slide to roll ratio (SRR) of a circulating oil formulation with ETL 40 (IE!) as compared to a corresponding circulating oil formulation with PAO 40 (CE1). At a typical application temperature of 80°C, at an SRR of 40, there is a significant improvement of 19% (e.g„ a 19% reduction in coefficient of friction) for ETL 40 vs. the comparative example of PAO 40. This improvement is seen in all temperatures and slide to roll ratios. As known in the industry, this can lead to improved energy efficiency in the application, leading to lower greenhouse gas emissions. This is an unexpected result as PAO is considered a standard for energy efficiency. This change is even more pronounced for blends with PAO 6. FIGS. 2A-2D shows the traction coefficient as a function of SRR. of a circulating oil formulation with a blend of ETL100 and PAO 6 (IE3) as compared to a corresponding circulating oil formulation with PAO 100 and PAO 6 (CE2). At a typical application temperature of 80°C, at an SRR of 40, there is a significant improvement of 26% for the inventive example with ETL 100 PAO 6 vs. the comparative example with PAO 100. PAO 6.

[0149] Accordingly, the lubricating formulations of the present disclosure provide comparatively or improved formulations compared to more costly, currently used high performance synthetic PAO base stock circulating oils. The higher Viscosity Index (VI) of the lubricants with ETL vs. PAO should result in higher fluidity at low temperatures and thicker films at high temperatures relative to the PAO references. This will allow the oil to be used at lower temperatures, and provide better lubrication at higher temperatures, relative to the PAO references. These extended lite, temperature, and energy efficiency results can be extended to other formulations containing ETL Circulating oils have ISO VG 100-680. To blend the full viscosity, PAO 6, PAO 40 and PAO 100 (or by comparison, ETL. 6, ETL 40 and ETL 100) can be introduced. See Tables 3A and 3B below, illustrating a total of seven (7) prophetic Comparative Examples (“PCE1”-“PCE7”) and seven (7) prophetic Inventive Examples f‘PIEl*’-‘‘PIE7”) (data based on physics-based models).TABLE 3ATABLE 3B

[0150] Additionally alternate Group V co-oil base stocks can be used. These include, but are not limited to, esters and alkylated aromatics. The co-oil base stock can be added at 15-30%, optimally 20-25%. A typical additive package for a circulating oil may contain: antioxidant, rust inhibitor, friction modifier, antiwear, antifoam, demulsifier, metal passivator, or a combination thereof. The package can range from O.5%-5%, optimally 1-2%.Example 3 - Formulated Paper Machine Oils

[0151] Paper machine oils are a specific class of circulating oils used in modem paper manufacturing machines. Paper manufacturing is a very energy intensive process. Due to the large amount of oil in an oil tank, often more than 10,000 gallons, paper machine oils must have high oxidation stability. Paper machine oils must also have stability under high steam pressures, temperatures, and high machine speeds of paper manufacturing equipment, the ability to handle caustic and acidic water from the paper making process, and the ability to keep the bearings clean and free of deposits.

[0152] T his Example provides various suitable formulations for paper machine oils of the present disclosure. Table 4 compares kinematic viscosity, viscosity index, and viscosity increase after B10 of two (2) formulations including a Comparative Example (“CE”) and an Inventive Example (“IE”). Note, “OTL” is also referred to herein as “ETC’.TABLE 4

[0153] Improved oxidation stability can lead to longer oil life in the paper machine. Table 4 shows improved viscosity increase control in the ExxonMobil B10 oxidation test (already described inmultiple US patents, e.g.. US 4,981 ,492) for the inventive example with ETL 40 vs. the PAO 40 comparative example, run at the very severe conditions of 163°C for 120 hrs. This is unexpected as PAO 40 has exceptional oxidation stability.

[0154] I he inventive example also gives improved energy efficiency (as shown by a reduced traction coefficient). FIGS. 3A-3D shows the traction coefficient as a function of slide to roll ratio (SRR) of a paper machine oil formulation with ETL 40 (IE) as compared to a corresponding paper machine oil formulation with PAO 40 (CE). At a typical application temperature of 80°C, at a SRR of 50, there is a significant improvement of 13% vs. the comparative example of PAO 40. This improvement is seen at all temperatures and slide to roll ratios. As known in the industry, this can lead to improved energy efficiency in the application, leading to lower greenhouse gas emissions. This is an unexpected result as PAO is considered a standard for energy efficiency. Additionally, as the viscosity of the ETL 40 blend is higher than the PAO 40 blend, one would expect that to have a negative impact on energy efficiency. Thus, the improvement in the inventive example is even more significant,

[0155] T hese extended life and energy efficiency results can be extended to other formulations containing ETL. Paper machine oils range from ISO VG 150 to ISO VG 460. In order to blend the full viscosity, PAO 6, PAO 40 and PAO 100 can be used. By comparison, ETL 6, ETL 40 and ETL 100 can be introduced. See Tables 5A and 5B below, which illustrate five (5) prophetic Comparative examples (‘TCEF’-'fPCES’'), one (1) Inventive example from Table 4 (“IE2”), and four (4| prophetic inventive examples (“PIE1” andi4PlE3”-'tPIE5”) (data based on physics-based models).TABLE 5ATABLE 5B[01561 Additionally, alternate Group V co-oil base stocks can be used. These include, but are not limited to, esters and alky lated naphthalenes. The co-oil base stock can be added at 15-30%, optimal ly 20-25%. A typical additive package for a paper machine oil may contain: antioxidant, antiwear, dispersant, detergent, antifoam, demulsifier, and metal passivator agents. The package can range from 3%-10%, optimally 4-8 % and more optimally 6-7%. In summary, this patent memo describes a method to improve energy efficiency and oil life for a paper machine oil and the composition required to achieve these improvements.Trample.4, - Fomt dated Gear

[0157] Gear oils are a specific class of lubricating oils. Gear oils are lubricating oils used in gear applications where torque is transmittedindustrial gearboxes or transmissions). In contrast to other lubricating oils, which typically experience either sliding or rolling motion, gear oil contacts are a mixture of sliding and rolling under high pressure. The gear oil in gear contacts is compressed and sheared, resulting in heat generation and energy loss. It is desired to minimize energy loss in order to reduce operating temperatures, which extends oil and gearbox longevity and increases power output from a gearbox. Gear oils operate in the presence of contaminants and debris. Further, gear oils require exceptional oi l life, often tens of thousands of hours. Due to the mill ions of gallons of these oi ls used annually, these oils require high thermal stability and oxidation resistance, high load-carrying capacity, high film strength, appropriate viscosity, low temperature fluidity, or a combination thereof.

[0158] This Example provides various suitable formulations for gear oils of the present disclosure. Inventive examples, including ETL 40, as previously shown in Example 3, illustrate improved energy efficiency (e.g., as measured by reduced traction coefficients shown) suitable for formulated papermachine oils as well as for formulated gear oils. However, formulated gear oils should have a viscosity grade of ISO VG 150-680. Tables 6A and 6B provide prophetic examples of twelve (12) inventive formulated gear oils containing ETL 40 (“PIEr,-“PlE!2*’). Tables 7A and 7B provide prophetic examples of thirteen (13) inventive formulated gear oils containing ETL 40 and optionally ETL 100 (“PIEL’- TIE 13”) (data based on physics-based models).TABLE 6ATABLE 6BTABLE 7 ATABLE 7B

[0159] A typical additive package for a gear oil may contain: antioxidant, rust inhibitor, friction modifier, antiwear, antifoam, demulsifier, metal passivator, or a combination thereof. The package can range from 0.5%-5%, optimally 1-2%.Example 5 - Base Oils Suitable For Industrial Lubricant Oil Formulations

[0160] This Example provides various suitable base oil blends suitable for industrial oil formulations of the present disclosure (e.g., without a VII or Additive Package), suitable for the lubrication of mobile and stationary mechanical systems and components, which comprise, e.g., mobile or stationary systems, mobile or stationary power systems, vehicles, engines, pistons, piston rings, cylinder liners, cylinders, cam shafts, cams, tappets, lifters, bearings (journal, roller, tapered, needle, ball, and others), drivelines, drivetrains, powertrains, transmissions, power transfer systems, dilTerentials, gears, gear trains, gear sets, gearboxes, bearings, bushings, axles, turbines, compressors, pumps, hydraulic systems, valves, seals, filters, and others. See Table 8 below, which illustrates four (4) Comparative examples (“CE I ”-“CE4”), and two (2) Inventive examples (“IE 1” and “IE2”).TABLE 8

[0161] The inventive example also gives improved energy efficiency (as shown by a reduced traction coefficient). FIG. 4 shows the traction coefficient as a function of slide to roll ratio (SRR) of a paper machine oil formulation with blends of PAO 6 with ETL 100 (IE1) or ETL 40 (IE2) as compared to a corresponding paper machine oil formulation with blends of PAO 6 with PAO 100 (CE1), mPAO 100 (CE2), PAO 40 (CE3), or EHC 340 Max™ (CE4). At a typical application temperature of 100'"C, at a SRR of 40, there is a significant improvement of 40% (e.g., 40% lower coefficient of traction) for ETL 100 / PAO 6 vs, the comparative example of PAO 100 / PAO 6, and a significant improvement of 21% of ETL 40 • PAO 6 vs. the comparative example of PAO 40 PAO 6. As known in the industry, this can lead to improved energy efficiency in the application, leading to lower greenhouse gas emissions. This is an unexpected result as PAO is considered a standard for energy efficiency. Additionally, as the viscosity of the ETL 40 blend is higher than the PAO 40 blend, one would expect that to have a negative impact on energy efficiency. Thus, the improvement in the inventive example is even more significant.Example 6 - Oil Base Stocks Suitable tor Base Oils and Formulated Lubricants

[0162] This Example provides a comparison of ETL oil base stock with standard oil base stocks used in base oils suitable for lubricant formulations, including, but not limited to, gas-to-liquid (GTL), polyalphaolefin (PAO), and ethylene a-olelin copolymer (EAO) oil base stocks. FIG. 5 shows the molecular weight curve of ETL 100 vs PAO 100 as determined from gel permeation chromatography (GPC) (Calibration: linear polyethylene (polystyrene standard) in the 500 - "6-7 million g / mol; temperature 145°C, solvent ™ L2,4-trichlorobenzene, refractive index detection). Table 9 shows the molecular weights calculated from GPC data for E TL, 40, ETL 100, PAO 40 and PAO 100. Results show that KVl 00 values and polydispersity increases with increasing molecular weight (Mn<Mw, and MK), and that ETL oil base stocks have slightly lower molecular weight (Mtl, Mw, and Mz) and polydispersitycompared to PAO oil base stocks of equivalent KVl 00 value.FABLE 9

[0163] FIG. 6 A shows FT- ICR MS with LDI (Ag) spectra of metallocene PAO (mPAO) 100, PAO 100 (SpeclrasynlM100), Eli., 100, and EAO 100 (Lucantf MHC-100), where differences in peak spacing indicate differences in degree of branching and branch size. FIG. 6B shows FT -ICR MS with LDI (Ag) spectra of ETL 100 (Peak: 978; Range: 500-2500; Carbon # 70 (36-180), ETL 40 (Peak; 893; Range: 500-2000: Carbon # 64 (36- 150), and PAO 100 ((SpectrasynlM100) (Peak: I 250; Range: 500-3000; Carbon # 90 (36-220).

[0164] FIG. 7A shows! KNMR chemical shifts observed for a branched hydrocarbon. FIG. 7B shows a comparison oft3CNMR spectra of ETL oil base stocks vs. GTL 8 (Shell QHVI 8), PAO 10 (Spectrasynf M1.0), PAO 100 (Spectrasynf M100 ). and EAO 100 (Lucantf MHC-100) oil base stocks. In FIG. 7B, thespectra show that EAO 100 has the highest ratio of pendant methyl (P-Me) ( 1 ) and alpha carbon (2) groups. While ETL oil base stocks have a more even number of P-Me groups and Alpha carbons, ETL 40 has slightly more alpha carbon groups than pendant methyl groups (3). PAO oil base stocks lack pendant methyl groups (4), while GTL 8 oil base stock has more alpha carbons than pendant methyl groups (5).

[0165] Table I0A similarly showsiXNMR chemical shifts observed for a branched hydrocarbon. Table 10B shows branching characteristics of ETL, GTL, PAO, and EAO oi l base stocks determined based onLKNMR, »NMR, and DEPT NMR experiments (data in mol%). Table 10B shows that ETL oil base stocks have less straight alkyl chain wax-like character (i.e., significantly lower numbers of Epsilon carbons) versus PAO oil base stocks, but more than EAO oil base stocks. Further, ETL has a higher amount of branching (i.e. , more P-Me groups and more short chain methyl branching) compared to PAO and GTE oil base stocks, but less than EAO oil base stock. Table 10B indicates four unique molar ratios which distinguish ETO oil base stocks from typical base stocks, inchiding: Pendant Methyl Groups to Alpha Carbons; Epsilon Carbons to Methyl Branches; Total Methyl Groups to Short Chain Methyl Branches; and Total Methylene and Methine Groups to Total Methyl Groups, Table 10C summarizes the data from Table 10B.TABLE 10ATABLE 10BTABLE 10C

[0166] FIG. 8A shows a chart plotting thentNMR molar ratio of pendant methyl groups alpha carbons on the y-axis versus theiX'NMR molar ratio of epsilon carbons methy l branches on the x- axis for each of ETL 40 and ETL 100 oil base stocks. From this chart; the number of pendant methyl groups is expected to decrease linearly with molecular weight for an ETL oil base stock, and similarly, the number of alpha methyl groups should remain more constant - thus decreasing the molar ratio. On the other hand, the epsilon carbons to methyl branches molar ratio should increase more slowly with E TL oil base stock size, as it just repeats its structure.

[0167] Thus, an optimal space for ET L oil base stocks is predicted to exist, and Tables 10A and 10B can be used to predict results for ETL oil base stocks having much lower K.V100 values. Accordingly, for a full range of ETL oil base stocks, much wider molar ratios than those shown in Table 10 B can be predicted: a molar ratio of total methyl groups to short chain methyl groups offrom 0.9 / 1 to 1.8 / 1, as determined byHNMR; a molar ratio of total methylene and methine groups to total methyl groups of from 2 / 1 to 4.5 / 1 , as determined byHNMR; a molar ratio of pendant methyl groups to alpha-methyl groups of from 1.2 / 1 to 3.6 / 1 , as determined byl3tNMR; and a molar ratio of epsilon carbons to methyl branches of from 0.92 / 1 to 1.4 / 1 , as determined byncNMR.

[0168] FIG. 8B shows a chart plotting the,ANMR molar ratio of pendant methyl groups / alpha carbons on the y-axis versus the,XNMR molar ratio of epsilon carbons methyl branches on the x- axis for each of ETL 40 and ETL 100 oil base stocks as well as other commercial oil base stocks. Unique to ETL oil base stocks is the fact that epsilon carbons- methyl branches molar ratios are very low for I TT oil base stocks as compared io PAO and GTL (Group 111 - Fischer- Tropsch) oil base stocks. This result is attributed to the number of methylene groups away from branches and the number of terminal methyls, which are expected to be lower. Also unique to ETL oil base stocks is the lower pendant methyl group / alpha carbon ratio versus other olefin oligomer derived base stocks, indicating a mix of longer alkyl (e.g,, > 4C) branches and methyl branches.

[0169] S imilarly, FIG. 8C shows a chart plottingiXNMR methyl branches versusi ,tNMR epsilon carbons, FIG. 8D shows a chart plottingBCNM'R alpha carbons versus)3CNMR pendant methyl groups, and FIG. 8E shows! MNMR pendant methyl groups versusncNMR epsilon carbons, which each illustrate the differences in structure between ETL oil base stocks and other commercial oil base stocks.

[0170] FIG. 9A shows a chart of the volatility (TGA NOACK %Off) versus viscosity (KV100) of ETL oil base stocks as compared to GTL and PAO oil base stocks. FIG. 9B shows the viscosity index (VI) versus viscosity (KV40) of ETL oil base stocks, as compared to GTL and PAO oil base stocks, FIG. 9C shows the pour point of ETL oil base stocks as compared to GTL and PAO oil base stocks. In FIG. 9A, the volatility (TGA NOACK %Off) of ETL oil base stocks was shown to be inversely proportional to viscosity- (KV100). In FIG. 9B, the viscosity index (VI) of ETL oil base stocks was shown to be higher than the VI of PAO and G TL oil base stocks of similar viscosity (KV40). The pour point (°C) of ETL oil base stocks, shown in FIG. 9C, was generally lower than the pour point of PAO.

[0171] FIG. 10A shows the Rotary Pressure Vessel Oxidation Test (RPVOT) oxidative stability (min) or the DSC oxidative induction temperature (°C) (performed by Pressure Differential Scanning Calorimetry (PDSC)) of ETL oil base stocks, as compared to PAO and GTL oil base stocks. In FIG. 10A, the RPVOT (min) or the DSC oxidative induction temperature (°C) for the ETL oil base stocks was similar to those of PAO and GTL oil base stocks, although ETL showed slightly faster take-upof O2 in RPVOT. FIG. I OB shows the oxidative stability as a comparison of the viscosity (KV100, cSt) before and after RPVOT testing for ETL oil base stocks, as compared to PAO and GTL oil base stocks. In FIG. 10B, the oxidative stability of ETL oil base stocks, shown by the comparison of viscosity (KV100, cSt) before and after RPVOT testing, indicated comparable performance with PAO and GI L, oil base stocks. At higher viscosity, ETL, oil base stocks showed greater oxidative cleavage than PAO oil base stocks, with the difference possibly due to the increased number of branch points in ETL oil base stocks.

[0172] The shear stability (viscosity (KV100) change after a KRL20 Shear Stability Test) of ETL oil base stocks is shown in FIG. 11 A (ETL .100) and FIG. 1 I B (ETL 40), versus PAO 100 or PAO 40 (SpeetraSyn1 M“SS” 100 or 40) oil base stock, respectively. KV100 viscosity of ETL and PAO oil base stocks showed no change after a KRL20 Shear Stability Test, A summary of the performance of ETL oil base stocks as compared to P / XO and G I L oil base stocks is shown in Table 11 .TABLE 11

[0173] I able 11 shows that ETL 100 oil base stock had a lower pour point, reflective of different branching, and similar oxidative stability as compared to PAO 100 and GTL S.

[0174] FIGS. 12A-12B show plots of the traction coefficient versus SRR (%) of ETL 100 oil base stocks versus PAO 100 oil base stocks. In each of FIGS. 12A- 12B, ETL oil base stocks demonstrated better traction performance, as indicated by lower traction coefficient vs. SRR (%), than PAO oil base stocks. Traction performance is important for various industrial applications (&g., wind turbine applications with gears and rolling element bearings).

[0175] The better traction performance of ETL oil base stocks vs PAO oil base stocks is unexpected, based on the more branched molecular structure of ETL oil base stocks vs. the more linear molecular structure of PAO oil base stocks. FIG. 13 shows a plot of the traction coefficient versus SRR % for ETL 100 versus PAO 100 and EAO 100 (e,g., Lucant™ HC-100) oil base stocks. The EAO oil base stock, which is even more highly branched than ETL, exhibited worse traction performance than both the PAO and the ETL oil base stock.

[0176] While various embodiments have been shown and described herein, modifications may be made by one skilled in the art without departing from the scope of the present disclosure. The embodiments described herein are exemplary only and are not intended to be limiting. Many variations, combinations, and modifications of the embodiments disclosed herein are possible and are within the scope of the disclosure. .Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims.

[0177] Therefore, the present invention is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular examples and configurations disclosed above are illustrative only, as the present invention may be modified and practiced in di fferent but. equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative examples disclosed above may be altered, combined, or modified and all such variations are considered within the scope and spirit of the present invention. The invention illustratively disclosed herein suitably may be practiced in the absence of any element that is not specifically disclosed herein and / or any optional element disclosed herein. While compositions and methods are described in terms of “comprising,"' “containing?" or “including” various components or steps, the compositions and methods can also“consist essentially of’ or “consist of” the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about A to about B,” or, equivalently, “from approximately A to B,” or, equivalently, “from approximately A-B”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a a””or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces.

[0178] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties, such as molecular weight, reaction conditions, and so forth used in the present specification and associated claims are to be understood as being modified in all instances by the term “about,” Accordingly, unless indicated to the contrary', the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the incarnations of the present inventions. At the very least, and not as an. attempt to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0179] One or more illustrative incarnations incorporating one or more invention elements are presented herein. Not all features of a physical implementation are described or shown in this application for the sake of clarity. It is understood that in the development of a physical embodiment incorporating one or more elements of the present invention, numerous implementation-specific decisions must be made to achieve the developer’s goals, such as compliance with system-related, business-related, government-related, and other constraints, which vary by implementation and from time to time. While a developer’s efforts might be time-consuming, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in the art and having benefit of this disclosure.

Claims

CLAIMSWhat is claimed is:

1. A circulating oil composition comprising a base oil and a performance additive package, wherein the base oil comprises at least a first oil base stock and a second oil base stock: wherein the first oil base stock is an OTL oil base stock having a molar ratio of' pendant methyl groups to a-methyl groups of from 1.2 1 to 5.4 / 1 , as determined by carbon 13 nuclear magnetic resonance spectroscopy (L>LNMR); and wherein the second oil base stock comprises one or more Group I, Group II, Group U+, Group III, Group 111 + , Group IV, or Group V oil base stocks, or any combination thereof.

2. The circulating oil composition of claim 1, wherein the first oil base stock is an OTL oil base stock having:(a) a molar ratio of epsilon carbons (E-C) to methyl branches of from 0.92 1 to 1 ,4 / 1, as determined by!xNMR;(b) a molar ratio of total methyl groups to short chain methyl groups of from 1.1 1 to 1.8 / 1 , as determined by proton nuclear magnetic resonance spectroscopy (HNMR);(c) a molar ratio of total methylene and methine groups to total methyl groups of from 2 / 1 to 4.5 / 1, as determined byHNMR; or,(d) some combination of (a), (b), and (c).

3. The circulating oil composition of any preceding claim, wherein the OTL, oil base stock a lower number average molecular weight (Ma), weight-average molecular weight (Mw), z-average molecular weight (Mz), and / or polydispersity, as determined by GPC analysis, as compared to a polyalphaolefin (PAO) or a gas-to-liquid (GTL) oil base stock having an equivalent kinematic viscosity at 100"C (KV100), as determined by ASTM D445 or D7279, to the O I L oil base stock.

4. The circulating oil composition of any precedi ng claim, wherein the OT L oil base stock has: a kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or ASTM D7279 orASTM D7042, of from 60 to 1 100: a kinematic viscosity' at 100°C (KV100), as determined by ASTM D445 or ASTM 1)7279 or ASTM D7042, of from 10 to 100;a viscosity index, as determined by ASTM D2270, of from 145 to 200; a pour point, as determined by IP 15 or ASTM D97 or ASTM D7345 of-60°C to -40°C; a KV100 % loss, as determined by CEC L-45-AA-99, of zero % (0%); and / or a coefficient of traction, as determined by Mini-Traction Machine, at a slide-roll ratio (SRR) of from 40" •, to 100%, and at a temperature of from 40°C to 100°C, of from 0.010 to 0.040.

5. The circulating oil composition of any preceding claim, wherein the OTL oil base stock is present at from 30 wt.% to 99 wt.%, based on the total weight of the base oil; and / or wherein the second oil base stock is present at from 1 wt.% to 70 wt.%, based on the total weight of the base oil.

6. The circulating oil composition of any preceding claim, wherein the second oil base stock comprises one or more Group II-1V oil base stocks, and wherein the second oil base stock has, as compared to the OTL oil base stock: a lower kinematic viscosity at 40°C (KV40), as determined by AS TM D445 or ASTM D7279 or ASTM D7042; a lower kinematic viscosity at 100°C (K.V100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042; and / or a lower viscosity index, as determined by ASTM D2270.

7. The circulating oil composition of any preceding claim, wherein the circulating oil composition has, as compared to the OTL oil base stock: a higher viscosity index, as determined by ASTM D2270; a lower B10 viscosity % increase, as determined by ExxonMobil B10 oxidation test; and or a lower coefficient of traction , as determined by Mini-Traction Machine, under a constant speed, temperature, load, and slide-roll-ratio (SRR); as compared to a circulating oil composition comprising, as the first oil base stock of the base oil composition, a polyalphaolefin (PAO) oil base stock, a gas-to-Iiquid (GTL) oil base stock, or an ethylene-alpha-olefin copolymer (EAO) oil base stock having an equivalent kinematic viscosity at 100°C (KV100), as determined by ASTM D445 or D7279,8. The circulating oil composition of any preceding claim, wherein the circulating oil composition has:a kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or A STM D7279 or ASTM D7042, of from 200 cSt to 300 cSt; a kinematic viscosity at 100%' (KV100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 25 eSt to 35 cSt; a viscosity index, as determined by ASTM D2270, of from 140 to 180; a B10 viscosity % increase, as determined by ExxonMobil B10 oxidation test, of 10 % or less; and / or a coefficient of traction, as determ ined by Mini-Traction Machine, at a slide-roll ratio (SRR) of from 40% to 100%, and at a temperature of from 40°C to 100%', of 0.010 to 0.040.

9. A method for improving the energy efficiency and / or the oxidation stability of a circulating oil composition, the method comprising: providing a base oil for a circulating oil composition, the base oil comprising at least a first oil base stock arid a second oil base stock, wherein providing the base oil optionally comprises blending the first oil base stock with the second oil base stock; optionally, blending the base oil with a performance additive package, thereby forming the circulating oil composition; wherein the first oil base stock is an OTL oil base stock having: a molar ratio of pendant methyl groups to a-mefhyl groups of from 1.2 / 1 to 5.4 / 1, as determined by carbon 13 nuclear magnetic resonance spectroscopyand wherein the second oil base stock comprises one or more Group 1. Group II, Group 11+ , Group HI, Group 1H+, or Group IV, Group V oil base stocks, or any combination thereof.10, The method of claim 9, wherein the first oil base stock is an OTL oil base stock having(a) a molar ratio of epsilon carbons (e-C) to methyl branches of from 0.92 / 1 to 1 .4 / 1 , as determined by1 HNMR;(b) a molar ratio of total methyl groups to short chain methyl groups of from 1.1 / 1 to 1.8 / 1 , as determined by proton nuclear magnetic resonance spectroscopy (HNMR);(c) a molar ratio of total methylene and methine groups to total methyl groups of from 2 / 1 to 4.5 / 1 , as determined byHNMR: or,(d) some combination of (a), (b), and (c).11 . The method of claim 9 or 10, wherein the OTL oil base stock a lower number average molecular weight (Mn), weight-average molecular weight (Mw), z-average molecular weight (Mz), and / or polydispersity, as determined by GPC analysis, as compared to a polyalphaolefin (PAO) or a gas-to-liquid (GTL) oil base stock having an equivalent kinematic viscosity at 100°C (KV100), as determined by ASTM D445 or D7279. to the OTL oil base stock.

12. The method of any of claims 9-1 1 , wherein the OTL oil base stock has: a kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 60 io i 100; a kinematic viscosity at 100°C ( KV 100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 10 to 100; a viscosity index, as determined by ASTM D2270, of from 145 to 200; a pour point, as determined by IP 15 or ASTM D97 or ASTM D7345 of -60°C to -40°C; a KV100 % loss, as determined by CEC L-45-AA-99, of zero % (0%); and or a coefficient of traction, as determined by Mini -Traction Machine, at a slide-roll ratio (SRR) of from 40% to 100%, and at a temperature of from 40°C to 100 'C, of from 0.010 to 0.040.

13. The method of any of cla ims 9-12, wherein the OTL oil base stock is present at from 30 wt.% to 99 wt.%, based on the total weight of the base oil; and / or wherein the second oil base stock is present at from 1 wt.% to 70 wt.%, based on the total weight of the base oil.

14. The method of any of claims 9-13 , wherein the second oil base stock comprises one or more Group Il-IV oil base stocks, and wherein the second oil base stock has: a lower kinematic viscosity at 40°C (KV40), as determined by ASTM D445 or ASTM D7279 or ASTM D7042; a lower kinematic viscosity at 100°C (KV100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042; and / or a lower viscosity index, as determined by ASTM D2270; as compared to the OTL oil base stock.

15. The method of any of claims 9-14, wherein the circulating oil composition comprises a viscosity index improver; and / or wherein rhe second oil base stock comprises a Group V oil base stock comprising one or more of the group consisting of an ester, a naphthalene compound, a polyoxyalkylene glycol (PAG), an ester thereof, an ether thereof, a phosphate, and any combination thereof.

16. The method of any of claims 9-15, wherein the circulating oil composition has: a higher viscosity index, as determined by ASTM D2270; a lower BIO viscosity % increase, as determined by ExxonMobil BI O oxidation test; and / or a lower coefficient of traction, as determined by Mini-Traction Machine, under a constant speed, temperature, load, and slide-roll-ratio (SRR); as compared to a circulating oil composition comprising, as the first oil base stock of the base oil composition, a polyalphaolefin (PAO) oil base stock, a gas-to-Iiquid (GTL) oil base stock, or an ethylene-alpha-olefiri copolymer (EAO) oil base stock having an equivalent kinematic viscosity at 100°C (K V I 00), as determined by ASTM D445 or D7279, to the OTL oil base stock.

17. The method of any of claims 9- 16, wherein the circulating oil composition has: a kinematic viscosity at 40°C (KAMO), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 200 cSt to 300 cSt; a kinematic viscosity at I O()°C (KV100), as determined by ASTM D445 or ASTM D7279 or ASTM D7042, of from 25 cSt to 35 cSt: a viscosity index, as determined by ASTM D2270, of from 140 to 180; a B10 viscosity % increase, as determined by ExxonMobil B l 0 oxidation test, of 10 % or less; and / or a coefficient of traction, as determined by Mini-Traction Machine, at a slide-roll ratio (SRR) of from 40% to 100%, and at a temperature of from 4(FC to 100'JC, of 0.010 to 0.040.

Images