POLYOXYALKYLENE GLYCOL DIETHER LUBRICATING COMPOSITION

PREPARATION AND USE

This application is a non-provisional application claiming priority from the U.S. Provisional Patent Application No. 61/048,296, filed on April 28, 2008, entitled "POLYOXYALKYLENE GLYCOL DIETHER LUBRICATING COMPOSITION

PREPARATION AND USE," the teachings of which are incorporated by reference herein, as if reproduced in full hereinbelow.

In various aspects, this invention relates generally to a lubricating composition that comprises a polyoxyalkylene glycol diether, a method of lubricating components, especially surfaces of components that move relative to one another and more especially components of an internal combustion engine that are in contact with and move relative to one another, with the lubricating composition and a method of preparing the lubricating composition.

A number of commercially available lubricating compositions comprise a hydrocarbon base fluid derived from petroleum and a complex combination of additives that enhance base fluid performance in one or more attributes including, without limitation, pour point, heat stability, oxidative stability, anti-foaming, corrosion resistance, and yellow metal passivity.

Other commercially available lubricating compositions, nominally "synthetic lubricants", include those comprising a polyalkylene glycol (e.g. a compound with terminal hydroxy moieties and, optionally, an internal hydroxy moiety). Polyalkylene glycol (PAG) base fluids tend to be characterized as having inherent low friction properties (e.g. a coefficient of friction < 0.12, measured at 55 degrees Centigrade ( ⁰ C) on an OPTIMOL™

SRV machine at a 200 newton (N) load, 1.0 millimeter (mm) stroke and a frequency of 50 hertz (Hz) (according to American Society for Testing and Materials (ASTM) D5706-05) and good low and high temperature viscosity profiles (e.g. a kinematic viscosity (KV) of from 32 centistokes (cSt) (32 x 10 ^"6 square meters per second (m ² /s) or 32 mm ² /s to 72 cSt

(72 x 10 ^"6 m ² /s or 72 mm ² /s) (at a low temperature such as 40 ⁰ C, a viscosity of from 5 cSt

(5 x 10 ^"3 m ² /s or 5 mm ² /s) to 14 cSt (14 x 10 ^"3 m ² /s or 14 mm ² /s) at a high temperature such as 100 ⁰ C (ASTM D445/446), and a viscosity index (VI) within a range of from 65 to 193 (ASTM 3448). Suitable PAGs include SYNALOX™ 100-D20 or SYNALOX™ 100-50B commercialized by The Dow Chemical Company. SYNALOX 100-D20 is an International

Standards Organization (ISO) Grade 32 fluid and SYNALOX 100-50B is an ISO Grade 68 fluid according to ISO Standard 3448.

United States Patent (USP) 2,839,468 to Stewart et al. discloses jet turbine lubricant compositions that include, as a base fluid, an alkyl diether of a mixed oxyethylene/1,2- oxypropylene glycol polymer. The base fluid may be represented by Formula 1 as follows:

R ₁ -(EO) _n -(PO) _1n -O-R ₂ (Formula 1) where EO is an ethylene oxide moiety, PO is a propylene oxide moiety, R ₁ and R ₂ each represent an alkyl group that contains from 1 to 18 carbon atoms (C ₁ to Ci ₈ ), n has a value of at least (>) one and m has a value of > two. The base fluid has a molecular weight (or average molecular weight) of from 350 Daltons to 700 Daltons and a viscosity between 5,000 cSt (5 x 10 ^~3 square meters per second (m ² /s) or 5000 mm ² /s) and 12,000 cSt (12 x 10 ^{" 3} m ² /s or 12,000 mm ² /s) at a temperature of -65° Fahrenheit ( ⁰ F) (-53.9 ⁰ C) and between 2.5 cSt (2.5 x 10 ^"6 m ² /s or 2.5 mm ² /s) and 3.5 cSt (3.5 x 10 ^"6 m ² /s or 3.5 mm ² /s) at a temperature of 210 ⁰ F (98.9 ⁰ C). USP 2,801,968 to Furby et al. describes jet turbine lubricant compositions similar to those of USP 2,839,468 except that n equals zero in Formula 1 above.

USP 6,759,373 to Tazaki teaches refrigerating oil compositions for a carbon dioxide refrigerant comprising a base oil that comprises a polyoxyalkylene glycol having a KV of from 3 mm ² /s (3 x 10 ^"6 m ² /s) to 50 mm ² /s at 100 ⁰ C and at least one component selected from (a) a carbonate-based carbonyl derivative and (b) a polyol ester, wherein (a) and/or (b) has a KV of from 3 mm ² /s to 50 mm ² /s at 100 ⁰ C.

USP 6,306,803 to Tazaki includes teachings relative to refrigerator oils comprising a base oil that comprises an oxygen-containing organic compound as an essential component and has a KV of from 5 mm ² /s to 50 mm ² /s at 100 ⁰ C and a VI of at least 60. Suitable oxygen-containing organic compounds include those represented by Formula 2 as follows:

R ¹ -[(OR ² ) _m -OR ³ ] _n (Formula 2) where R ¹ represents a hydrogen atom, a C ₁ -C ₁ O alkyl group, a C ₂ -C ₁ O acyl group or a C ₁ -C ₁ O aliphatic hydrocarbon group having from 2 to 6 bonding sites, R ² is a C ₂ -C ₄ alkylene group, and R ³ represents a hydrogen atom, a C ₁ -C ₁ O alkyl group, or a C ₂ -C ₁ O acyl group. Illustrative compounds represented by Formula 2 include polyoxyalkylene glycol ethers (e.g. a polyoxypropylene glycol dimethyl ether or a polyoxyethylene-oxypropylene glycol dimethyl ether), polyvinyl ethers, polyesters and carbonates, and mixtures thereof.

Japanese Patent Publication (JPP) 2007-204451 discloses compounds suitable for use as a lubricant base oil or a lubricant composition. The compounds comprise a tetraether compound having a structure represented by a Formula 3:

R ₁ -O-CHR ₂ -CHR ₃ -O-CHR ₄ -CHR ₅ -O-CHR ₆ -CHR ₇ -O-R ₈ (Formula 3) (wherein Ri and Rg each independently represents a C ₆ -Ci ₄ alkyl group; and combinations of R ₂ and R ₃ , R ₄ and R ₅ , and R ₆ and R ₇ , each of which one is a methyl group and the other is a hydrogen atom), and a diether compound having a structure represented by general Formula 4:

R ₉ -0-CH ₂ -CH(C ₂ H ₅ )-CH ₂ -CH(C ₂ H ₅ )-CH ₂ -0-Rio (Formula 4) (wherein R ₉ and Ri ₀ each independently represents a C ₆ to Ci ₄ alkyl group). Lubricating compositions may contain various additive agents such as an antioxidant, a lubricity improver, a detergent additive, a conductive addition agent, a rust-proofer, a metal deactivator, a defoaming agent, a VI improver, and a pour point depressant.

JPP 2007-137953 discusses a lubricating composition for a refrigeration apparatus, the composition comprising a base oil composition that, in turn, comprises as least one of a monoether compound, an alkylene glycol diether, and a polyoxyalkylene glycol diether that has an average repeating number of the oxyalkylene group of two or less, and a KV within a range of from one mm ² /s to eight mm ² /s at 40 ⁰ C.

In some aspects, this invention is a lubricating composition that comprises a polyoxyalkylene glycol diether represented by Formula 5:

Ri-(EO) _x -(AO) ₇ -R ₂ (Formula 5) where Ri and R ₂ are each independently an alkyl moiety that contains from one to 12 carbon atoms (Ci-Ci ₂ alkyl moiety) or an aryl moiety that contains from one to 12 carbon atoms (Ci-Ci ₂ aryl moiety), an alicyclic moiety that contains from one to 12 carbon atoms (Ci-Ci ₂ alicyclic moiety), or a heterocyclic moiety that contains from one to 12 carbon atoms (Ci- Ci ₂ heterocyclic moiety), EO is an ethylene oxide moiety, AO is an alkylene oxide moiety that contains from three to 14 carbon atoms (C ₃ -Ci ₄ alkylene oxide moiety), and x and y are independent integers within a range of from zero to 50, provided that at least one of x and y is an integer greater than (>) zero but less than or equal (<) to 50. The polyoxyalkylene glycol diether of Formula 5 may be a homopolymer (where one of x and y equals zero), a random copolymer (as opposed to a block copolymer), a block copolymer, or a reverse block copolymer. "Homopolymer", "random copolymer", "block

copolymer", and "reverse block copolymer" are each defined below. Formula 5 may be expressed as is for a block copolymer or as Ri-(AO) _y -(EO) _x -R ₂ for a reverse block copolymer without departing from this invention's spirit or scope.

In some aspects, this invention is a method of lubricating components (preferably components of an internal combustion engine) or surfaces of said that are in contact with, and move relative to one another, which method comprises placing said components in contact with a lubricating composition that comprises a polyoxyalkylene glycol diether represented by Formula 5.

In some aspects, this invention is a method of preparing the polyoxyalkylene glycol diether of Formula 5, the method comprising steps (preferably sequential): a) reacting a PAG with an amount of an alkali metal alkoxide to form a first reaction product that comprises a polyoxyalkylene glycol alkali metal alkoxide and an alkanol; b) heating the first reaction product at a first elevated temperature and a reduced pressure in conjunction with an inert gas purge for a first period of time, the first elevated temperature, the reduced pressure, the inert gas purge and the first period of time being sufficient to remove at least a major portion of the alkanol from the first reaction mixture to provide a stripped first reaction product; c) reacting the stripped first reaction product with an alkyl halide (e.g. alkyl chloride) at a second elevated temperature and for a second period of time, the second elevated temperature and second period of time being sufficient to convert at least a portion of the stripped first reaction product to a second reaction product, the second reaction product comprising a polyoxyalkylene diether, an alkali metal halide (e.g. alkali metal chloride) and a dialkylether; and d) recovering the polyoxyalkylene diether from the second reaction product.

The alkali metal halide and dialkyl ether constitute byproducts, both of which are preferably removed from the polyoxyalkylene diether during step d) which preferably includes one or more of three sub-steps dl) through d3). Substep dl) comprises washing the second reaction product with water, and allowing the washed second reaction product to separate into a water or aqueous layer and an organic layer. Substep d2) comprises separating the water layer from the organic layer, preferably by way of a first substep d2a) of decanting the water layer, which includes a major portion (i.e. more than 50 percent by weight (wt%)) of alkali metal halide originally present in the second reaction product, and a second substep d2b) of adding magnesium silicate to the organic layer to adsorb at least a

portion, preferably substantially all and more preferably all of any residual alkali metal halide that may be present therein. Substep d2) yields a washed and stripped second reaction product. Substep d3) comprises removing at least a portion of alkyl halide from the stripped second reaction product, as well as any residual water and dialkylether byproduct contained in the stripped second reaction product. Substep d3) preferably comprises a first substep d3a) of removing the water and residual alkyl halide by distillation and a second substep d3b) of recrystallizing the alkali metal halide and separating the recrystallized alkali metal halide from the stripped second reaction product.

The PAG, prior to etherification, preferably has a number average molecular weight (M _n ) that lies within a range of from 150 Dal tons to 5,000 Daltons. The range is preferably from 200 Daltons to 2000 Daltons, more preferably from 300 Daltons to 1500 Daltons, and still more preferably from 500 Daltons to 1400 Daltons.

The PAG may be one or more of a homopolymer, a random copolymer, a block copolymer, or a reverse block copolymer. "Homopolymer", as used herein, means a polymer having polymerized therein a single polymerizable monomer. For example, PAG homopolymer consists of a chain of identical alkylene oxide moieties or monomer.

"Random copolymer", as used herein, means a polymer having polymerized therein at least two different monomers in a random distribution or order. For example, a PAG random copolymer consists of a chain of at least two different alkylene oxide moieties (e.g. EO and PO) reacted in random order. One may prepare a random copolymer by adding the different monomers at the same time, especially if the monomers have similar reaction rates, to a catalyst.

"Block copolymer", as used herein, means a polymer having polymerized therein at least two different monomers, each of said monomers being disposed in a long sequence of two or more monomeric units or moieties linked together by chemical valences in a single chain, such that a chain or section of one monomer is separated from another section of the same monomer by a chain or section of the other monomer. For example, a PAG block copolymer consists of a chain of at least two different alkylene oxide molecules (e.g. EO and PO), each of which is disposed in one or more chains or sections that contain only molecules of that alkylene oxide, such sections being arranged in alternating form such that one alkylene oxide (e.g. EO) is separated from another section of the same alkylene oxide

(e.g. EO) by a chain, block or segment of a second alkylene oxide (e.g. PO). One may prepare a block copolymer by placing a first monomer in contact with a catalyst and allowing polymerization of the first monomer to proceed substantially to completion before adding a second monomer and allowing polymerization of the second monomer to proceed substantially to completion prior to termination of polymerization if one desires a diblock copolymer, or addition of either another aliquot of the first monomer or a third monomer and allowing polymerization of that aliquot to proceed substantially to completion before either termination or addition of another aliquot of the second monomer, where only the first and second monomer are present in polymerized form, or another aliquot of either the first monomer or the second monomer when the third monomer is added and each of the first, second and third monomers are present in polymerized form. Skilled artisans recognize that one may prepare any number of blocks using this technique. Skilled artisans also recognize that one may prepare block copolymers via coupling technology wherein a coupling agent links at least two copolymer segments. By way of example only, a triblock copolymer has end blocks of one polymerized monomer and a midblock that contains segments of a second polymerized monomer linked together via a coupling agent.

"Normal block copolymer", as used herein, means a block copolymer that has a recognized structure such as a triblock EO/PO block copolymer with EO end blocks separated by a PO midblock. "Reverse block copolymer", as used herein, means is a block copolymer that has a structure opposite that of the normal block copolymer, e.g. a PO/EO block copolymer with PO end blocks separated by an EO midblock.

"Capping efficiency", as used herein, refers to a percentage determined by multiplying a quotient by 100, the quotient having number of terminal hydroxy (-OH) moieties present prior to capping as a denominator and number of terminal hydroxy moieties that are replaced by terminal -OR moieties as a numerator. R refers to an alkyl, aryl, cycloaliphatic (alicyclic) or heterocyclic moiety.

When ranges are stated herein, as in a range of from 2 to 10, both end points of the range (e.g. 2 and 10) and each numerical value, whether such value is a rational number or an irrational number, are included within the range unless otherwise specifically excluded.

References to the Periodic Table of the Elements herein shall refer to the Periodic Table of the Elements, published and copyrighted by CRC Press, Inc., 2003. Also, any

references to a Group or Groups shall be to the Group or Groups reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups.

Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percents are based on weight. For purposes of United States patent practice, the contents of any patent, patent application, or publication referenced herein are hereby incorporated by reference in their entirety (or the equivalent US version thereof is so incorporated by reference) especially with respect to the disclosure of synthetic techniques, definitions (to the extent not inconsistent with any definitions provided herein) and general knowledge in the art. The term "comprising" and derivatives thereof does not exclude the presence of any additional component, step or procedure, whether or not the same is disclosed herein. In order to avoid any doubt, all compositions claimed herein through use of the term "comprising" may include any additional additive, adjuvant, or compound whether polymeric or otherwise, unless stated to the contrary. In contrast, the term, "consisting essentially of" excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability. The term "consisting of" excludes any component, step or procedure not specifically delineated or listed. The term "or", unless stated otherwise, refers to the listed members individually as well as in any combination. Expressions of temperature may be in terms either of degrees Fahrenheit ( ⁰ F) together with its equivalent in ⁰ C or, more typically, simply in ⁰ C.

Preferred polyoxyalkylene glycol diethers represented by Formula 5 have an EO content that ranges from 40 wt% to 80 wt%, preferably from 45 wt% to 78 wt%, and more preferably from 46 wt% to 76 wt%, and a complementary AO content that ranges from 60 wt% to 20 wt%, preferably from 55 wt% to 22 wt%, and more preferably from 54 wt% to 24 wt%, the wt% being based upon combined weight of EO and AO and wt% for EO and wt% for AO, when combined, equal 100 wt%. The diethers have a M _n that preferably ranges from 200 Daltons to 2000 Daltons and more preferably from 300 Daltons to 1500 Daltons. The diethers preferably have a KV at 40° C that is less than that of the polyalkylene glycol used as a raw material to prepare the diethers. The KV at 40° C preferably lies within a range of from 10 cSt to 70 cSt. The range is more preferably from 10 cSt (10 x 10 ^" m /s or 10 mm ² /s) to 65 cSt (65 x 10 ^" m ² /s or 65 mm ² /s), and still more preferably from 11 cSt (11

x 10 ^~6 m ² /s or 11 mm ² /s)to 62 cSt (62 x 10 ^~6 m ² /s or 62 mm ² /s). The diethers preferably have a VI in excess of 220, more preferably in excess of 225 and still more preferably in excess of 230. The VI may be as high as 263 or even higher without departing from this invention's spirit or scope. Illustrative VI numbers, as shown in Ex 1 through Ex 5 below are 228 (Ex 3), 234 (Ex 1), 248 (Ex 2), 256 (Ex 5) and 263 (Ex 4). Similar VI numbers are expected with use of higher alkylene oxides such as butylene oxide, pentylene oxide, hexylene oxide, heptylene oxide and octene oxide as AO in formula 5. AO need not be a single alkylene oxide. One may, in fact, combine two or more alkylene oxides (e.g. propylene oxide and butylene oxide) as AO in Formula 5 without departing from this invention's spirit or scope.

The lubricating composition used in some aspects or embodiments of this invention optionally, and in some instances preferably, also comprises a VI improver selected from a group consisting of ultra high molecular weight polyethylene oxide homopolymers as described in USP 6,080,461 to Wozniak et al., the relevant teachings of which are incorporated herein by reference (e.g. POLYOX™ WSR resins commercially available from The Dow Chemical Company); and/or selected from a group of polyalkyl methacrylates, polyalkyl ethers, ether ethylenically unsaturated carboxylic acid copolymers, and ethylenically unsaturated carboxylic acid ester copolymers as described in USP 6,355,712 to Schultes et al., the relevant teachings of which are incorporated herein by reference (e.g. Viscoplex resins commercially available from RohMax).

In addition to lubricating components of an internal combustion engine that move relative to one another, lubricating compositions that comprise a polyoxyalkylene glycol diether represented by Formula 5 above, may also be used to lubricate components of a drive train of a vehicle powered by an internal combustion engine, a steam engine or a diesel engine or to lubricate components, especially surfaces of components, which surfaces and components are proximate to one another, of an apparatus (e.g. a pump, a computer disk drive, a mechanical clock mechanism, a gear box, a turbine shaft, a roll bearing, or a conveyor belt) that comprises at least two components wherein a surface of one component moves relative to a surface of another component, said surfaces being proximate to one another. Skilled artisans recognize that, absent use of a lubricating composition, such movement, especially movement wherein the surfaces are in physical contact, generates

substantial friction and heat that, in extreme cases, could effectively fuse at least a portion of one surface to the other surface and halt relative movement between the surfaces. Examples

The following examples illustrate, but do not limit, the present invention. All parts and percentages are based upon weight, unless otherwise stated. All temperatures are in ⁰ C. Examples (Ex) of the present invention are designated by Arabic numerals and Comparative Examples (CE) are designated by capital alphabetic letters. Unless otherwise stated herein, "room temperature" and "ambient temperature" are nominally 25 ⁰ C. Ex I: Polyalkylene glycol (PAG) 1 is butanol-initiated EO/PO block copolymer that is commercially available from The Dow Chemical Company under the trade designation SYNALOX™ 50-15B. PAG 1 has a number average molecular weight (M _n ) of 500 Daltons, a hydroxy number of 109.9, a KV at 40° C of 19.4 cSt (19.4 x 10 ^"6 m ² /s or 19.4 mm ² /s), a KV at 100° C of 4.8 cSt (4.8 x 10 ^"6 m ² /s or 4.8 mm ² /s), a VI of 181. PAG 1 has a nominal composition that comprises 10 wt% butanol, 48 wt% EO and 42 wt% PO, each wt% being based upon total weight of butanol, EO and PO.

Place 5519 grams (g) of PAG 1 in a closed, stirred reactor and heat the PAG 1 with stirring at a rate of 174 revolutions per minute (rpm), under a reduced pressure of less than three millibars (mbar) (300 pascals (Pa)) and under a nitrogen purge using 200 milliliters per minute (ml/min) of gaseous nitrogen, at a set point temperature of 80 ° C for a period of 30 minutes to yield dried PAG 1.

Cool the dried PAG 1 to a set point temperature of 40 ° C, open the reactor, add 3018 g of a 25 wt% solution of sodium methoxide (NaOCHs) in methanol (an approximate 25% excess of NaOCH ₃ ), close the reactor, heat reactor contents to a set point temperature of 120° C for a period of 23 hours with continued stirring to facilitate alkoxide formation and removal of methanol. Over the period of 23 hours, gradually reduce pressure within the reactor from approximately 500 mbar (50,000 Pa) to less than 5 mbar (500 Pa), continue the nitrogen purge and stirring.

After the 23 hours lapse, add 860 g of methyl chloride (CH ₃ Cl) (an approximate excess of 20%) in an initial aliquot of 125 g at the set point temperature of 120° C, with the remaining 735 g being added over a period of 40 minutes after reducing the set point temperature of 80° C, halting the nitrogen flow, increasing reactor pressure to 2.47 bar (2.47

x 10-1 megapascal (MPa), and increasing stirrer speed to 230 rpm. After completing CH ₃ Cl addition, allow contents of the reactor to react over a period of 100 minutes during which pressure within the reactor rises to 3.02 bar (3.02 x 10 ^"1 MPa).

Reduce reactor pressure to 200 mbar (20,000 Pa) and reactor set point temperature to 80° C, then flash reactor contents for 20 minutes at a set point temperature of 80° C while reducing reactor pressure to 4 mbar (400 Pa), flowing gaseous nitrogen through the reactor at a flow rate of 200 ml/min, and stirring at 200 rpm to remove unreacted CH ₃ Cl and dimethylether byproduct.

Add 2497 g of water to contents of the reactor, then stir reactor contents for a period of 35 minutes at a set point temperature of 80° C and a stirring rate of 267 rpm to cause sodium chloride (NaCl) within the reactor contents to go into solution with the water.

Allow reactor contents to settle without stirring at the set point temperature of 80° C for a period of 90 minutes into an aqueous layer and an organic layer. Decant the aqueous layer and a minor portion (approximately 20 ml) of the organic layer from the reactor. Add 100 g of magnesium silicate to remaining reactor contents, then continue heating reactor contents at the set point temperature of 80° C for a period of 30 minutes while reducing pressure from 200 mbar (20,000 Pa) to less than 10 mbar (1,000 Pa), continuing stirring at 174 rpm, and flowing nitrogen through the reactor contents at a flow rate of 200 ml/min to further reduce water contained in the reactor contents. Reduce pressure to less than 5 mbar (500 Pa) and continue the nitrogen flow, set point temperature and stirring for an additional period of 60 minutes.

Discharge reactor contents (approximately 5044 g) onto a filter that comprises 100 g of magnesium silicate precoated on a 1 x 604 filter paper and two GF/B glass fiber filters to yield 4927 g of clear poly-(EO/PO) glycol diether product. The product has a capping conversion of 100%, a KV at 40 ° C of 11.3 cSt (11.3 x 10 ^"6 m ² /s or 11.3 mm ² /s), a KV at 100° C of 3.6 cSt (3.6 x 10 ^"6 m ² /s or 3.6 mm ² /s), and a VI of 234. Ex 2:

PAG 2 is butanol-initiated EO/PO block copolymer that is commercially available from The Dow Chemical Company under the trade designation SYNALOX™ 50-25B. PAG 2 has a M _n of 770 daltons, a hydroxy number of 57.7, a KV at 40° C of 30.7 cSt (30.7 x 10 ^"6 m ² /s or 30.7 mm ² /s), a KV at 100° C of 7.0 cSt (7.0 x 10 ^"6 m ² /s or 7.0 mm ² /s), a VI of

201. PAG 2 has a nominal composition that comprises 7 wt% butanol, 43 wt% EO and 50 wt% PO, each wt% being based upon total weight of butanol, EO and PO.

Using PAG 2 rather than PAG 1, replicate Ex 1 with changes. First, use 5912 gram of PAG 2 rather than 5519 g of PAG 1. Second, reduce the amount of 25% NaOCH ₃ in methanol solution to 2122 g (an approximate 20% excess of NaOCH ₃ ). Third, modify CH3C1 addition by adding 595 g of CH ₃ Cl (an approximate 20% excess of CH ₃ Cl) over 25 minutes, using a set point temperature of 86° C during CH ₃ Cl addition before reducing the set point temperature to 80° C, increasing stirrer speed to 267 rpm and increasing time during which reactor contents react to 120 minutes during which time the reactor pressure rises to 2.07 bar (2.07 x 10 ^"1 MPa). Fourth, modify water addition by reducing amount of water to 1709 g, stirring rate to 200 rpm and settling time to one hour. Fifth, modify silicate addition by increasing stirrer speed to 200 rpm.

The product has a capping conversion of 100%, a KV at 40 ° C of 20.6 cSt (20.6 x 10 ^"6 m ² /s or 20.6 mm ² /s), a KV at 100° C of 5.7 cSt (5.7 x 10 ^"6 m ² /s or 5.7 mm ² /s) and a VI of 248. Ex 3:

Replicate Ex 2, but use PAG 3, rather than PAG 2. PAG 3 is a butanol-initiated PO homopolymer that is commercially available from The Dow Chemical Company under the trade designation SYNALOX™ 100-50B. PAG 3 has a M _n of 1362 daltons, a hydroxy number of 41.2, a KV at 40° C of 71.9 cSt (71.9 x 10 ^"6 m ² /s or 71.9 mm ² /s), a KV at 100° C of 13.9 cSt (13.9 x 10 ^"6 m ² /s or 13.9 mm ² /s), a VI of 201. PAG 3 has a nominal composition that comprises 5 wt% butanol, and 95 wt% PO, each wt% being based upon total weight of butanol and PO.

The product has a capping conversion of 96.6%, a KV at 40° C of 56.3 cSt (56.3 x 10 ^"6 m ² /s or 56.3 mm ² /s), a KV at 100° C 12.5 cSt (12.5 x 10 ^"6 m ² /s or 12.5 mm ² /s), and a VI of 228 Ex 4:

Replicate Ex 2, but use PAG 4, rather than PAG 2. PAG 4 is a butanol-initiated EO/PO block copolymer that is commercially available from The Dow Chemical Company under the trade designation SYNALOX™ 50-50B. PAG 4 has a M _n of 1385 daltons, a hydroxy number of 40.5, a KV at 40° C of 78.1 cSt (78.1 x 10 ^"6 m ² /s or 78.1 mm ² /s), a KV at 100° C of 16.0 cSt (16.0 x 10 ^"6 m ² /s or 16.0 mm ² /s), a VI of 220. PAG 4 has a nominal

composition that comprises 5 wt% butanol, 47.5 wt% EO and 47.5 wt% PO, each wt% being based upon total weight of butanol, EO and PO.

The product has a capping conversion of 99.8%, a KV at 40° C of 60.4 cSt (60.4 x 10 ^"6 m ² /s or 60.4 mm ² /s), a KV at 100° C 15.0 cSt (15.0 x 10 ^"6 m ² /s or 15.0 mm ² /s), and a VI of 263. Ex 5:

Replicate Ex 2, but use PAG 5, rather than PAG 2. PAG 5 is a butanol-initiated EO/PO block copolymer that is commercially available from The Dow Chemical Company under the trade designation SYNALOX™ 25-50B. PAG 5 has a M _n of 1184 daltons, a hydroxy number of 47.4, a KV at 40° C of 75.2 cSt (75.2 x 10 ^"6 m ² /s or 75.2 mm ² /s), a KV at 100° C of 15.8 cSt (15.8 x 10 ^"6 m ² /s or 15.8 mm ² /s), a VI of 225. PAG 5 has a nominal composition that comprises 6 wt% butanol, 71 wt% EO and 23 wt% PO, each wt% being based upon total weight of butanol, EO and PO. (75/25 feed)

The product has a capping conversion of 94.5%, a KV at 40° C of 56 cSt (56 x 10 ^"6 m ² /s or 56 mm ² /s), a KV at 100° C 13.7 cSt (13.7 x 10 ^"6 m ² /s or 13.7 mm ² /s), and a VI of 256.

Similar results follow with other PAGs including, but not limited to, a PAG that is based on a) a butylene oxide homopolymer, b) a butylene oxide/propylene oxide block copolymer; and c) an octene oxide/propylene oxide block copolymer. Ex 1 through Ex 5 present a variety of PO-based and EO/PO-based PAGs that, when converted to PAG diethers, show a reduction in KV at temperatures of 40° C and 100° C and a concurrent increase in VI, both of which are believed desirable in lubricating internal combustion engine components.

The PO and EO/PO based diethers of this invention are mineral oil tolerant, but not fully soluble in, or miscible with, mineral oil. "Mineral oil tolerant", as used herein, means that up to 7 wt% of a PO- or EO/PO- or PO/EO- based diether may be blended with a mineral oil without phase separation, the wt% being based upon combined weight of mineral oil and diether. Incorporation of a higher alkylene oxide-based diether, such as butylene oxide-based, pentylene oxide-based, hexylene-oxide based, heptylene oxide-based or octene oxide-based diethers should increase solubility of the diethers in mineral oil to at least 10 wt% and possibly to 30 wt% or more without phase separation, in each case based upon combined weight of diether and mineral oil. Alkylene oxides selected from butylene

oxide, pentylene oxide, hexylene oxide, heptylene oxide, and octene oxide, have greater solubility in mineral oil than either ethylene oxide or propylene oxide. Skilled artisans recognize that replacing terminal hydroxy moieties with an alkoxy moiety, such as methylene oxide, reduces polarity relative to the same molecule prior to replacement, and a reduction in polarity should improve solubility.

An improvement in solubility of a diether composition in mineral oil limits problems that arise when one inadvertently or unintentionally blends a mineral oil lubricant with a polyalkylene glycol diether lubricating composition that is used to lubricate components of an internal combustion engine in accord with of this invention. As solubility of polyalkylene glycol diethers in mineral oil improves, potential further opportunities arise such as assisting in incorporation of additives that are not soluble or only sparingly soluble in currently available or soon to be available non-polar mineral and synthetic oils (e.g. Gas To Liquid Oils). See, e.g. Lisa Tocci, Lubes'n'Greases. February 2008. pages 34-39 (LNG Publishing Co., Inc.), and Johan Thoen and Martin Greaves, TAE Esslingen 16 ^th International Colloquium Tribology, January 2008, page 215, ISBN-Nr. 3-924813-73-6.

Subject PAG-I, PAG-2 and their respective diether products (Ex 1 and Ex 2) to rheology testing using a Thermohaake Rheo Stress 600 cone-plate rheometer with a 60 mm diameter cone, 1° angle and a programmed logarithmic shear rate increase from I/second (sec ¹ ) to 1000/second (sec ^-1) and summarize test results in Table 1 below where η _Newt Newtonian Dynamic Viscosity and is expressed as millipascal- second (mPa-s).

Table 1

The data presented in Table 1 show that diether capping of a polyoxyalkylene glycol substantially reduces its dynamic viscosity at temperatures of 40° C, 100° C, and 150° C.

Similar reductions should appear with other temperatures. Dynamic viscosity is an expression of dynamic performance of an incompressible Newtonian fluid. The dynamic viscosity data at low shear rate (1/sec ^"1 to 10/sec ^"1 ) indicate that capping of a polyalkylene glycol substantially reduces its dynamic viscosity over the temperature range measured. The data in Table 1 suggest that M _n also has an effect upon how much diether capping alters dynamic viscosity. PAG-I has a lower Mn than PAG-2 and the data in Table 1 show a greater reduction in dynamic viscosity between PAG-I and PAG-I diether than between

PAG-2 and PAG-2 diether.

Tables 2 through 5 below present dynamic viscosity data (in terms of η _Newt and units of Pa-s) at shear rates (Gp), expressed in units of sec ^"1 or 1/s, respectively for PAG-I, PAG- 1 diether, PAG-2 and PAG-2 diether at varying shear rates as shown in Tables 2 through 5 and at temperatures of 40° C, 100° C and 150° C.

means not measured

Table 3 - PAG-I Diether

means not measured

Table 4 - PAG-2

* means not measured

Table 5 - PAG-2 Diether

* means not measured

The dynamic viscosity data presented in Tables 2 through 5 show that the reduction in dynamic viscosity due to diether capping of a polyoxyalkylene glycol as noted in Table 1 above extends across higher shear rates at the same temperatures. Fig. 2 below, which presents a dynamic viscosity hierarchy among PAG-I, PAG-I diether, PAG-2 and PAG-2 diether at the higher shear rates of Tables 2 through 5 graphically portrays this extension.

This suggests that the PAG diethers, characterized by low dynamic viscosity relative to the PAG from which they are prepared, retain excellent film-forming properties even at a shear rate of 1000 sec ^"1 and across a range of use temperatures as high as 150° C. Similar results are expected with further increases in shear rate and temperature, at least up to a point where degradation of the PAG diether begins.