AU2004312335B2 - Lubricating base oil with high monocycloparaffins and low multicycloparaffins - Google Patents

Description

WO 2005/066319 PCT/US2004/041165 LUBRICATING BASE OIL WITH HIGH MONOCYCLOPARAFFINS AND LOW MULTICYCLOPARAFFINS 5 FIELD OF THE INVENTION The invention relates to: a) a lubricating base oil with a low aromatics content, a high weight percent of all molecules with at least one cycloparaffin function, and a high ratio of weight percent of molecules 10 containing monocycloparaffins to weight percent of molecules containing multicycloparaffins; and b) a process for manufacturing the lubricating base oil of this invention. BACKGROUND OF THE INVENTION 15 Finished lubricants and greases used for various applications, including automobiles, diesel engines, natural gas engines, axles, transmissions, and industrial applications consist of two general components, a lubricating base oil and additives. Lubricating base oil is the major 20 constituent in these finished lubricants and contributes significantly to the properties of the finished lubricant. In general, a few lubricating base oils are used to manufacture a wide variety of finished lubricants by varying the mixtures of individual lubricating base oils and individual additives. 25 Highly saturated lubricating base oils in the prior art have either had very low levels of cycloparaffins; or when cycloparaffins were present, a significant amount of the cycloparaffins were multicycloparaffins. A certain amount of cycloparaffins are desired in lubricating base oils to provide additive solubility and elastomer compatibility. Multicycloparaffins are less 30 desired than monocycloparaffins, because they decrease viscosity index, lower oxidation stability, and increase Noack volatility. - 1 - WO 2005/066319 PCT/US2004/041165 Examples of highly saturated lubricating base oils having very low levels of cycloparaffins are polyalphaolefins and base oils made from Fischer Tropsch processes such as described in EPAI 114124, EPAI 114127, EPAI 114131, EPA776959, EPA668342, and EPA1029029. Lubricating 5 base oils in the prior art with high cycloparaffins made from Fischer Tropsch wax have been described in WO 02/064710. The examples of the base oils in WO 02/064710 had very low pour points and the ratio of monocycloparaffins to multicycloparaffins was less than 15. The viscosity indexes of the lubricating base oils in WO 02/064710 were below 140. 10 The Noack volatilities were between 6 and 14 weight percent. The lubricating base oils in WO 02/064710 were heavily dewaxed to achieve low pour points, which would produce reduced yields compared to oils that were not as heavily dewaxed. 15 The wax feed used to make the base oils in WO 02/064710 had a weight ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms greater than 0.20. These wax feeds are not as plentiful as feeds with lower weight ratios of compounds having at least 60 or more carbon atoms and compounds having at least 20 30 carbon atoms. The process in WO 02/064710 required an initial hydrocracking/hydroisomerizing of the wax feed, followed by a substantial pour reducing step. Lubricating base oil yield losses occurred at each of these two steps. To demonstrate this, in example 1 of WO 02/064710 the conversion of compounds boiling above 3700C to compounds boiling 25 below 3700C was 55 wt% in the hydrocracking/hydroisomerization step alone. The subsequent pour reducing step would reduce the yield of products boiling above 3700C further. Compounds boiling below 3700C (700 0 F) are typically not recovered as lubricating base oils due to their low viscosity. Because of the yield losses due to high conversions the process 30 requires feeds with a high ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms. -2- WO 2005/066319 PCT/US2004/041165 Due to their high saturates content and low levels of cycloparaffins, lubricating base oils made from most Fischer-Tropsch processes or polyalphaolefins may exhibit poor additive solubility. Additives used to make finished lubricants typically have polar functionality; therefore, they 5 may be insoluble or only slightly soluble in the lubricating base oil. To address the problem of poor additive solubility in highly saturated lubricating base oils with low levels of cycloparaffins, various co-solvents, such as synthetic esters, are currently used. However, these synthetic esters are very expensive, and thus, the blends of the lubricating base oils 10 containing synthetic esters, which have acceptable additive solubility, are also expensive. The high price of these blends limits the current use of highly saturated lubricating base oils with low levels of cycloparaffins to specialized and small markets. 15 It has been taught in US Patent Application 20030088133 that blends of lubricating base oils composed of 1) alkylated cycloparaffins with 2) highly paraffinic Fischer-Tropsch derived lubricating base oils improves the additive solubility of the highly paraffinic Fischer-Tropsch derived lubricating base oils. The lubricating base oils composed of alkylated 20 cycloparaffins used in the blends of this application are very likely to also contain high levels of aromatics (greater than 30 weight percent), such that the resulting blends with Fischer-Tropsch derived lubricating base oils will contain a weight percent of all molecules with at least one aromatic function greater than 0.30. The high level of aromatics will cause reduced 25 viscosity index and oxidation stability. What is desired are lubricating base oils with very low amounts of aromatics, high amounts of monocycloparaffins, and little or no multicycloparaffins, that have a moderately low pour point such that they 30 may be produced in high yield and provide good additive solubility and elastomer compatibility. Base oils with these qualities that also have good oxidation stability, high viscosity index, low Noack volatility, and good low -3- WO 2005/066319 PCT/US2004/041165 temperature properties are also desired. The present invention provides these lubricating base oils. What is desired is a process to make lubricating base oils with the desired 5 properties detailed above that is not limited to wax feeds having a weight ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms of at least 0.2. What is also desired is a process for making lubricating base oils with the desired properties that may be accomplished with a single hydroisomerization 10 dewaxing step that provides lower conversion of products boiling above 3700C (700'F+) to products boiling below 3700C (700*F-), and thus produces higher yields of lubricating base oil. SUMMARY OF THE INVENTION 15 The present invention is directed to a composition of lubricating base oil which comprises a weight percent of all molecules with at least one aromatic function less than 0.30, a weight percent of all molecules with at least one cycloparaffin function greater than 10, and a ratio of weight 20 percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater than 15. The present invention is also directed to a composition of lubricating base oil which comprises a weight percent of all molecules with at least one 25 aromatic function less than 0.30, a weight percent of all molecules with monocycloparaffins greater than 10, and a weight percent of all molecules with multicycloparaffins less than 0.1. The present invention is also directed to a composition of lubricating base oils which comprises a weight percent of all molecules with at least one 30 aromatic function less than 0.30, a weight percent of all molecules with at least one cycloparaffin function greater than the kinematic viscosity at 100 C in cSt multiplied by three, and a ratio of weight percent of molecules -4- WO 2005/066319 PCT/US2004/041165 containing monocycloparaffins to a weight percent of molecules containing multicycloparaffins greater than 15. The very low amount of aromatics provides excellent oxidation stability 5 and high viscosity index to the lubricating base oil. The high amount of all molecules with at least one cycloparaffin function provides improved additive solubility and elastomer compatibility to the lubricating base oil. The very high ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing 10 multicycloparaffins (or high weight percent of molecules containing monocycloparaffins and little to no weight percent of molecules containing multicycloparaffins) optimizes the composition of the cycloparaffins. Molecules containing multicycloparaffins are less desired as they dramatically reduce the viscosity index, oxidation stability, and Noack 15 volatility of lubricating base oils. The present invention is also directed to a process for manufacturing a lubricating base oil with the steps of: a) performing a Fischer-Tropsch synthesis on syngas to provide a product stream; b) isolating from said 20 product stream a substantially paraffinic wax feed having less than about 30 ppm total combined nitrogen and sulfur and less than about 1 wt% oxygen; c) dewaxing said substantially paraffinic wax feed by hydroisomerization dewaxing using a shape selective intermediate pore size molecular sieve with a noble metal hydrogenation component, 25 wherein the hydroisomerization temperature is between about 600'F (315'C) and about 750"F (399*C), whereby an isomerized oil is produced; and d) hydrofinishing said isomerized oil, whereby a lubricating base oil is produced having: a low weight percent of all molecules with at least one aromatic function, a high weight percent of all molecules with at least one 30 cycloparaffin function, and a high ratio of weight percent molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins. -5- WO 2005/066319 PCT/US2004/041165 Using the process of the invention, high yields of lubricating base oils are prepared with good additive solubility, good elastomer compatibility, excellent oxidation stability, and low volatility. In addition, the viscosity indexes are high. The lubricating base oils of the present invention may 5 be used to prepare high quality finished lubricants, including automatic transmission fluids and multigrade engine oils, preferably without the addition of any ester co-solvent or viscosity index improver. This invention overcomes shortcomings of the prior art that focused on 10 reducing pour point and increasing total cycloparaffins in lubricating base oils made from Fisher-Tropsch wax. Producing base oils with very low pour points using hydroisomerization dewaxing may result in oils with high weight percents of all molecules with at least one cycloparaffin function, but at the expense of producing high weight percents of molecules 15 containing multicycloparaffins as well. High weight percents of molecules containing multicycloparaffins reduce oxidation stability and viscosity index. Yields of lubricating base oil are also significantly reduced as hydroisomerization dewaxing severity is increased to obtain lower pour points. Producing base oils with very low pour points from Fischer 20 Tropsch wax using solvent dewaxing results in oils with lower weight percents of all molecules with at least one cycloparaffin function. A certain high amount of cycloparaffins is desired to improve the additive solubility and elastomer compatibility of the lubricating base oil. 25 This invention overcomes shortcomings of the prior art that focused on processes to increase viscosity index in lubricating base oils made from substantially paraffinic wax feed wherein the substantially paraffinic wax feed has less than about 30 ppm total combined nitrogen and sulfur, and an oxygen content less than about 1 weight percent. High viscosity index 30 in the prior art lubricating base oils has been obtained by including a substantial amount of solvent dewaxing, which produces reduced amounts of total cycloparaffins compared to hydroisomerization dewaxing. High viscosity index in the prior art was also obtained by a process using -6- WO 2005/066319 PCT/US2004/041165 relatively narrow boiling Fischer-Tropsch feed with a T90-T1 0 between 40 to 150*C. This invention produces lubricating base oils with high viscosity indexes using Fischer-Tropsch feeds with both narrow boiling and wide boiling point distributions. 5 The very low amount of aromatics in the lubricating base oil provides excellent oxidation stability and high viscosity index. The high amount of all molecules with at least one cycloparaffin function provides improved additive solubility and elastomer compatibility to the lubricating base oil. 1d The very high ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins (or high weight percent of molecules containing monocycloparaffins and little to no weight percent of molecules containing multicycloparaffins) optimizes the composition of the cycloparaffins. 15 Molecules containing multicycloparaffins are less desired as they dramatically reduce the viscosity index, oxidation stability, and Noack volatility of lubricating base oils. The present invention is also directed to a lubricating base oil 20 manufacturing plant comprising: a) a means to produce a substantially paraffinic wax feed having less than about 30 ppm total combined nitrogen and sulfur, less than about 1 weight percent oxygen, greater than about 75 mass percent normal paraffin, less than 10 weight percent oil, a weight ratio of compounds having at least 60 or more carbon atoms and 25 compounds having at least 30 carbon atoms less than 0.18, and a T90 boiling point between 660'F and 1200'F; b) a means for hydroisomerization dewaxing said substantially paraffinic wax feed using a shape selective intermediate pore size molecular sieve comprising a noble metal hydrogenation component, wherein the hydroisomerization 30 temperature is between about 600*F (3150C) and about 750*F (3990C), to produce an isomerized oil; and c) a means for hydrofinishing the isomerized oil to produce lubricating base oils having low weight percents of all molecules with at least one aromatic function, high weight percents -7- WO 2005/066319 PCT/US2004/041165 of all molecules with at least one cycloparaffin function, and a high ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins. -8- 29994M0-1 -9 BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention are illustrated with reference to the accompanying non limiting drawings. 5 FIGURE 1 illustrates the plot of Kinematic Viscosity at 100 *C in cSt vs Pour Point in degrees Celsius/Kinematic Viscosity at 100 *C in cSt providing the equation for calculation of the Base Oil Pour Factor: Base Oil Pour Factor = 7.35 x Ln(Kinematic Viscosity at 100 *C)-18, wherein 10 Ln(Kinematic Viscosity at 100 *C) is the natural logarithm with base "e" of Kinematic Viscosity at 100 *C in cSt. FIGURE 2 illustrates the plots of Kinematic Viscosity at 100 'C in cSt vs Aniline Point in *F, providing the equation for calculation of the preferred Aniline Point upper limits based on 15 Kinematic Viscosity: Aniline Point, in degrees Fahrenheit = 36 x Ln(Kinematic Viscosity at 100 'C) +200, wherein Ln(Kinematic Viscosity at 100 *C) is the natural logarithm with base "e" of Kinematic Viscosity at 100 *C in cSt. 20 FIGURE 3 illustrates the plots of Kinematic Viscosity at 100 *C vs TGA Noack in Weight percent, providing the equations for calculation of the preferred Noack Volatility upper limits based on Kinematic Viscosity: Noack Volatility, Wt% = 1000 x (Kinematic Viscosity at 100 0 C in cSt) 7 , wherein the Kinematic Viscosity at 100 0 C is raised to the power of -2.7; and 25 Noack Volatility, Wt% = 900 x (Kinematic Viscosity at 100 *C in cSt)-", wherein the Kinematic Viscosity at 100 *C is raised to the power of -2.8. FIGURE 4 illustrates the plots of Kinematic Viscosity at 100 *C in cSt vs CCS Viscosity at -35 *C, in cP, providing the equations for calculation of the preferred CCS VIS (-35 0 C) upper 30 limits based on Kinematic Viscosity: CCS VIS (-35 0 C), cP = 38 x (Kinematic Viscosity at 100 *C) 3 , wherein the Kinematic Viscosity at 100 0 C in cSt is raised to the power of 3; and CCS VIS (-35 0 C), cP = 38 x (Kinematic Viscosity at 100 C) 2 8 , wherein the Kinematic Viscosity at 100 'C in cSt is raised to the power of 2.8.

WO 2005/066319 PCT/US2004/041165 DETAILED DESCRIPTION OF THE INVENTION 5 Lubricating base oils with very low aromatic content made prior to this invention have either had very low cycloparaffin content, or high cycloparaffin content with considerable levels of multicycloparaffins and/or very low pour points. The highest known ratio of monocycloparaffins to multicycloparaffins in lubricating base oils containing greater than 10 10 weight percent cycloparaffins and low aromatics content; was 13:1. The lubricating base oil with this high ratio was the base oil Example 3 from WO 02/064710. The pour point of this example base oil was extremely low, -45*C, indicating that it was severely dewaxed. Severe dewaxing of base oils to low pour points are made at a significant yield disadvantage 15 compared to lubricating base oils dewaxed to more moderate pour points. Lubricating base oils containing cycloparaffins are desired as cycloparaffins impart additive solubility and elastomer compatibility to these oils. Lubricating base oils containing very high ratios of 20 monocycloparaffins to multicycloparaffins (or high monocycloparaffins and little to no multicycloparaffins) are also desired as the multicycloparaffins reduce oxidation stability, lower viscosity index, and increase Noack volatility. Models of the effects of multicycloparaffins are given in V.J. Gatto, et al, "The Influence of Chemical Structure on the Physical 25 Properties and Antioxidant Response of Hydrocracked Base Stocks and Polyalphaolefins," J. Synthetic Lubrication 19-1, April 2002, pp 3-18. By virtue of the present invention, lubricating base oils are made which have very low weight percents of all molecules with at least one aromatic 30 function, high weight percents of all molecules with at least one cycloparaffin function, and high ratios of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins (or high weight percent of molecules containing - 10 - WO 2005/066319 PCT/US2004/041165 monocycloparaffins and very low weight percents of molecules containing multicycloparaffins). In preferred embodiments they will also have moderate pour points. Moderate pour points are achieved by producing oils with a ratio of pour point to kinematic viscosity at 100 "C greater than a 5 Base Oil Pour Factor, defined herein. High yields of these base oils may be obtained using a process comprising the steps of: a) performing a Fischer-Tropsch synthesis to provide a product stream, b) isolating from the product stream a substantially paraffinic wax feed having less than about 30 ppm total combined nitrogen and sulfur, and less than about I 10 weight percent oxygen, c) dewaxing said substantially paraffinic wax feed by hydroisomerization dewaxing using a shape selective intermediate pore size molecular sieve comprising a noble metal hydrogenation component, whereby an isomerized oil is produced, and d) hydrofinishing said isomerized oil whereby a lubricating base oil is produced having a weight 15 percent of all molecules with at least one aromatic function less than 0.30, a weight percent of all molecules with at least one cycloparaffin function greater than 10, and a high ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins (greater than 15). 20 Alternatively, step d) of the above process may be changed to: d) hydrofinishing said isomerized oil whereby a lubricating base oil is produced having a weight percent of all molecules with at least one aromatic function less than 0.30, a weight percent of all molecules with at least one cycloparaffin function greater than the kinematic viscosity at 25 100*C in cSt multiplied by three, and a ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater than 15. As a second alternative, step d) of the above process may be changed to: 30 c) hydrofinishing said isomerized oil whereby a lubricating base oil is produced having a weight percent of all molecules with at least one aromatic function less than 0.30, a weight percent of molecules containing - 11 - WO 2005/066319 PCT/US2004/041165 monocycloparaffins greater than 10, a weight percent of molecules containing multicycloparaffins less than 0.1. Kinematic viscosity is a measurement of the resistance to flow of a fluid 5 under gravity. Many lubricating base oils, finished lubricants made from them, and the correct operation of equipment depends upon the appropriate viscosity of the fluid being used. Kinematic viscosity is determined by ASTM D 445-01. The results are reported in centistokes (cSt ). The kinematic viscosities of the lubricating base oils of this 10 invention are between about 2 cSt and about 20 cSt, preferably between about 2 cSt and about 12 cSt. Pour point is a measurement of the temperature at which the sample will begin to flow under carefully controlled conditions. Pour point may be 15 determined as described in ASTM D 5950-02. The results are reported in degrees Celsius. Many commercial lubricating base oils have specifications for pour point. When lubricant base oils have low pour points, they also are likely to have other good low temperature properties, such as low cloud point, low cold filter plugging point, and low temperature 20 cranking viscosity. Cloud point is a measurement complementary to the pour point, and is expressed as a temperature at which a sample of the lubricant base oil begins to develop a haze under carefully specified conditions. Cloud point may be determined by, for example, ASTM D 5773-95. Lubricating base oils having pour-cloud point spreads below 25 about 35 0 C are also desirable. Higher pour-cloud point spreads require processing the lubricating base oil to very low pour points in order to meet cloud point specifications. The pour-cloud point spreads of the lubricating base oils of this invention are generally less than about 35 0 C, preferably less than about 25'C, more preferably less than about 10 C. The cloud 30 points are generally in the range of +30 to -30 C. Noack volatility of engine oil, as measured by TGA Noack and similar methods, has been found to correlate with oil consumption in passenger - 12 - WO 2005/066319 PCT/US2004/041165 car engines. Strict requirements for low volatility are important aspects of several recent engine oil specifications, such as, for example, ACEA A-3 and B-3 in Europe, and SAE J300-01 and ILSAC GF-3 in North America. Any new lubricating base oil developed for use in automotive engine oils 5 should have a Noack volatility no greater than current conventional Group I or Group 11 Light Neutral oils. The Noack volatility of the lubricating base oils of this invention are very low, generally less than an amount calculated by the equation: Noack Volatility, Wt% = 1000 x (Kinematic Viscosity at 100 C)-2.7. in 10 preferred embodiments the Noack volatility is less than an amount calculated by the equation: Noack Volatility, Wt% = 900 x (Kinematic Viscosity at 100*C)-2 8 Noack volatility is defined as the mass of oil, expressed in weight percent, 15 which is lost when the oil is heated at 250 degrees C and 20 mmHg (2.67 kPa; 26.7 mbar) below atmospheric in a test crucible through which a constant flow of air is drawn for 60 minutes (ASTM D 5800). A more convenient method for calculating Noack volatility and one which correlates well with ASTM D-5800 is by using a thermo gravimetric 20 analyzer test (TGA) by ASTM D-6375-99. TGA Noack volatility is used throughout this disclosure unless otherwise stated. The lubricating base oils of this invention may be blended with other base oils to improve or modify their properties (e.g., viscosity index, oxidation 25 stability, pour point, sulfur content, traction coefficient, or Noack volatility). Examples of base oils that may be blended with the lubricating base oils of this invention are conventional Group I base oils, conventional Group I base oils, conventional Group Ill base oils, other GTL base oils, isomerized petroleum wax, polyalphaolefins, polyinternalolefins, 30 oligomerized olefins from Fischer-Tropsch derived feed, diesters, polyol esters, phosphate esters, alkylated aromatics, alkylated cycloparaffins, and mixtures thereof. - 13 - WO 2005/066319 PCT/US2004/041165 Wax Feed: The wax feed used to make the lubricating base oil of this invention is substantially paraffinic with less than about 30 ppm total combined 5 nitrogen and sulfur. The level of oxygen is less than about 1 weight percent, preferably less than 0.6 weight percent, more preferably less than 0.2 weight percent. In most cases, the level of oxygen in the substantially paraffinic wax feed will be between 0.01 and 0.90 weight percent. The oil content of the feed is less than 10 weight percent as determined by ASTM 10 D 721. Substantially paraffinic for the purpose of this invention is defined as having greater than about 75 mass percent normal paraffin by gas chromatographic analysis by ASTM D 5442. Nitrogen Determination: Nitrogen is measured by melting the substantially 15 paraffinic wax feed prior to oxidative combustion and chemiluminescence detection by ASTM D 4629-96. The test method is further described in US 6,503,956, incorporated herein in its entirety. Sulfur Determination: Sulfur is measured by melting the substantially 20 paraffinic wax feed prior to ultraviolet fluorescence by ASTM 5453-00. The test method is further described in US 6,503,956. Oxygen Determination: Oxygen is measured by neutron activation analysis. 25 The wax feed useful in this invention has a significant fraction with a boiling point greater than 650OF (343'C). The T90 boiling points of the wax feed by ASTM D 6352 are preferably between 660"F (3490C) and 1200'F (6490C), more preferably between 900OF (482*C) and 1200*F (6490C), 30 most preferably between 1000"F (5380C) and 1200'F (6490C). T90 refers to the temperature at which 90 weight percent of the feed has a lower boiling point. - 14 - WO 2005/066319 PCT/US2004/041165 The wax feed preferably has a weight ratio of molecules of at least 60 carbons to molecules of at least 30 carbons less than 0.18. The weight ratio of molecules of at least 60 carbons to molecules of at least 30 carbons is determined by: 1) measuring the boiling point distribution of the 5 Fischer-Tropsch wax by simulated distillation using ASTM D 6352, 2) converting the boiling points to percent weight distribution by carbon number, using the boiling points of n-paraffins published in Table 1 of ASTM D 6352-98, 3) summing the weight percent of feed of carbon number 30 or greater, 4) summing the weight percent of feed of carbon 10 number 60 or greater, 5) dividing the sum of weight percent of feed of carbon number 60 or greater by the sum of weight percent of feed of carbon number 30 or greater. Other preferred embodiments of this invention use Fischer-Tropsch wax having a weight ratio of molecules having at least 60 carbons to molecules having at least 30 carbons less 15 than 0.15, or less than 0.10. The boiling range distribution of the wax feed useful in the process of this invention may vary considerably. For example the difference between the T90 and T1 0 boiling points, determined by ASTM D 6352, may be greater 20 than 950C, greater than 1600C, greater than 200'C, or even greater than 2250C. Fischer-Tropsch Synthesis and Fischer-Tropsch Wax 25 A preferred wax feed for this process is Fischer-Tropsch wax. Fischer Tropsch wax is a product of Fischer-Tropsch synthesis. During Fischer Tropsch synthesis liquid and gaseous hydrocarbons are formed by contacting a synthesis gas (syngas) comprising a mixture of hydrogen and carbon monoxide with a Fischer-Tropsch catalyst under suitable 30 temperature and pressure reactive conditions. The Fischer-Tropsch reaction is typically conducted at temperatures of from about 300 degrees to about 700 degrees F (about 150 degrees to about 370 degrees C) preferably from about 400 degrees to about 550 degrees F (about 205 -15- WO 2005/066319 PCT/US2004/041165 degrees to about 230 degrees C); pressures of from about 10 to about 600 psia, (0.7 to 41 bars) preferably 30 to 300 psia, (2 to 21 bars) and catalyst space velocities of from about 100 to about 10,000 cc/g/hr., preferably 300 to 3,000 cc/g/hr. 5 The products from the Fischer-Tropsch synthesis may range from C1 to C200 plus hydrocarbons, with a majority in the C5-C100 plus range. Fischer Tropsch synthesis may be viewed as a polymerization reaction. Applying polymerization kinetics, a simple one parameter equation can describe the 10 entire product distribution, referred to as the Anderson-Shultz-Flory (ASF) distribution: W', = (1 - a )' x n x a " Where W, is the weight fraction of product with carbon number n, and a is the ASF chain growth probability. The higher the value of a, the longer 15 the average chain length. The ASF chain growth probability of the C20+ fraction of the Fischer-Tropsch wax of this invention is between about 0.85 and about 0.915. The Fischer-Tropsch reaction can be conducted in a variety of reactor 20 types, such as, for example, fixed bed reactors containing one or more catalyst beds, slurry reactors, fluidized bed reactors, or a combination of different types of reactors. Such reaction processes and reactors are well known and documented in the literature. The slurry Fischer-Tropsch process, which is preferred in the practice of the invention, utilizes superior 25 heat (and mass) transfer characteristics for the strongly exothermic synthesis reaction and is able to produce relatively high molecular weight, paraffinic hydrocarbons when using a cobalt catalyst. In the slurry process, a syngas comprising a mixture of hydrogen and carbon monoxide is bubbled up as a third phase through a slurry which comprises a 30 particulate Fischer-Tropsch type hydrocarbon synthesis catalyst dispersed and suspended in a slurry liquid comprising hydrocarbon products of the synthesis reaction which are liquid under the reaction conditions. The - 16- WO 2005/066319 PCT/US2004/041165 mole ratio of the hydrogen to the carbon monoxide may broadly range from about 0.5 to about 4, but is more typically within the range of from about 0.7 to about 2.75 and preferably from about 0.7 to about 2.5. A particularly preferred Fischer-Tropsch process is taught in EP0609079, 5 also completely incorporated herein by reference for all purposes. Suitable Fischer-Tropsch catalysts comprise one or more Group VIII catalytic metals such as Fe, Ni, Co, Ru and Re, with cobalt being preferred. Additionally, a suitable catalyst may contain a promoter. Thus, 10 a preferred Fischer-Tropsch catalyst comprises effective amounts of cobalt and one or more of Re, Ru, Pt, Fe, Ni, Th, Zr, Hf, U, Mg and La on a suitable inorganic support material, preferably one which comprises one or more refractory metal oxides. In general, the amount of cobalt present in the catalyst is between about 1 and about 50 weight percent of the total 15 catalyst composition. The catalysts can also contain basic oxide promoters such as ThO2, La203, MgO, and TiO2, promoters such as ZrO2, noble metals (Pt, Pd, Ru, Rh, Os, Ir), coinage metals (Cu, Ag, Au), and other transition metals such as Fe, Mn, Ni, and Re. Suitable support materials include alumina, silica, magnesia and titania, or mixtures thereof. 20 Preferred supports for cobalt containing catalysts comprise titania. Useful catalysts and their preparation are known and illustrated in U.S. Patent 4,568,663, which is intended to be illustrative but non-limiting relative to catalyst selection. 25 Hydroisomerization Dewaxing According to the present invention, the substantially paraffinic wax feed is dewaxed by hydroisomerization dewaxing at conditions sufficient to produce lubricating base oil with a desired composition of cycloparaffins 30 and a moderate pour point. In general, conditions for hydroisomerization dewaxing in the present invention are controlled such that the conversion of the compounds boiling above about 700 *F in the wax feed to compounds boiling below about 700 *F is maintained between about 10 wt - 17 - WO 2005/066319 PCT/US2004/041165 % and 50 wt%, preferably between 15 wt% and 45 wt%. Hydroisomerization dewaxing is intended to improve the cold flow properties of a lubricating base oil by the selective addition of branching into the molecular structure. Hydroisomerization dewaxing ideally will 5 achieve high conversion levels of waxy feed to non-waxy iso-paraffins while at the same time minimizing the conversion by cracking. Hydroisomerization is conducted using a shape selective intermediate pore size molecular sieve. Hydroisomerization catalysts useful in the 10 present invention comprise a shape selective intermediate pore size molecular sieve and a catalytically active metal hydrogenation component on a refractory oxide support. The phrase "intermediate pore size," as used herein means a crystallographic free diameter in the range of from about 3.9 to about 7.1 Angstrom when the porous inorganic oxide is in the 15 calcined form. The shape selective intermediate pore size molecular sieves used in the practice of the present invention are generally 1-D 10-, 11- or 12-ring molecular sieves. The most preferred molecular sieves of the invention are of the 1 -D 10-ring variety, where 1 0-(or 11-or 12-) ring molecular sieves have 10 (or 11 or 12) tetrahedrally-coordinated atoms (T 20 atoms) joined by oxygens. In the 1-D molecular sieve, the 10-ring (or larger) pores are parallel with each other, and do not interconnect. Note, however, that 1 -D 10-ring molecular sieves which meet the broader definition of the intermediate pore size molecular sieve but include intersecting pores having 8-membered rings may also be encompassed 25 within the definition of the molecular sieve of the present invention. The classification of intrazeolite channels as 1-D, 2-D and 3-D is set forth by R. M. Barrer in Zeolites, Science and Technology, edited by F. R. Rodrigues, L.D. Rollman and C. Naccache, NATO ASI Series, 1984 which classification is incorporated in its entirety by reference (see particularly 30 page 75). Preferred shape selective intermediate pore size molecular sieves used for hydroisomerization dewaxing are based upon aluminum phosphates, such -18- WO 2005/066319 PCT/US2004/041165 as SAPO-1 1, SAPO-31, and SAPO-41. SAPO-1 I and SAPO-31 are more preferred, with SAPO-1 1 being most preferred. SM-3 is a particularly preferred shape selective intermediate pore size SAPO, which has a crystalline structure falling within that of the SAPO-1 I molecular sieves. 5 The preparation of SM-3 and its unique characteristics are described in U.S. Patent Nos. 4,943,424 and 5,158,665. Also preferred shape selective intermediate pore size molecular sieves used for hydroisomerization dewaxing are zeolites, such as ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM 57, SSZ-32, offretite, and ferrierite. SSZ-32 and ZSM-23 are more 10 preferred. A preferred intermediate pore size molecular sieve is characterized by selected crystallographic free diameters of the channels, selected crystallite size (corresponding to selected channel length), and selected 15 acidity. Desirable crystallographic free diameters of the channels of the molecular sieves are in the range of from about 3.9 to about 7.1 Angstrom, having a maximum crystallographic free diameter of not more than 7.1 and a minimum crystallographic free diameter of not less than 3.9 Angstrom. Preferably the maximum crystallographic free diameter is not more than 20 7.1 and the minimum crystallographic free diameter is not less than 4.0 Angstrom. Most preferably the maximum crystallographic free diameter is not more than 6.5 and the minimum crystallographic free diameter is not less than 4.0 Angstrom. The crystallographic free diameters of the channels of molecular sieves are published in the "Atlas of Zeolite 25 Framework Types", Fifth Revised Edition, 2001, by Ch. Baerlocher, W.M. Meier, and D.H. Olson, Elsevier, pp 10-15, which is incorporated herein by reference. If the crystallographic free diameters of the channels of a molecular sieve 30 are unknown, the effective pore size of the molecular sieve can be measured using standard adsorption techniques and hydrocarbonaceous compounds of known minimum kinetic diameters. See Breck, Zeolite Molecular Sieves, 1974 (especially Chapter 8); Anderson et al. J. Catalysis - 19- WO 2005/066319 PCT/US2004/041165 58, 114 (1979); and U.S. Pat. No. 4,440,871, the pertinent portions of which are incorporated herein by reference. In performing adsorption measurements to determine pore size, standard techniques are used. It is convenient to consider a particular molecule as excluded if does not reach 5 at least 95% of its equilibrium adsorption value on the molecular sieve in less than about 10 minutes (p/po=0.5;25 0 C). Intermediate pore size molecular sieves will typically admit molecules having kinetic diameters of 5.3 to 6.5 Angstrom with little hindrance. 10 Preferred hydroisomerization dewaxing catalysts useful in the present invention have sufficient acidity so that 0.5 grams thereof when positioned in a tube reactor converts at least 50% of hexadecane at 3700C, pressure of 1200 psig, a hydrogen flow of 160 ml/min, and a feed rate of 1 ml/hr. The catalyst also exhibits isomerization selectivity of 40 percent or greater 15 (isomerization selectivity is determined as follows: 100 x (weight % branched C16 in product)/(weight % branched C16 in product + weight % C13 in product) when used under conditions leading to 96% conversion of normal hexadecane (n-C16) to other species. 20 Hydroisomerization dewaxing catalysts useful in the present invention comprise a catalytically active hydrogenation noble metal. The presence of a catalytically active hydrogenation metal leads to product improvement, especially viscosity index and stability. The noble metals platinum and palladium are especially preferred, with platinum most especially 25 preferred. If platinum and/or palladium is used, the total amount of active hydrogenation metal is typically in the range of 0.1 to 5 weight percent of the total catalyst, usually from 0.1 to 2 weight percent, and not to exceed 10 weight percent. 30 The refractory oxide support may be selected from those oxide supports which are conventionally used for catalysts, including silica, alumina, silica-alumina, magnesia, titania, and combinations thereof. -20- WO 2005/066319 PCT/US2004/041165 The conditions for hydroisomerization dewaxing depend on the feed used, the catalyst used, whether or not the catalyst is sulfided, the desired yield, and the desired properties of the lubricant base oil. Conditions under which the hydroisomerization process of the current invention may be 5 carried out include temperatures from about 600 F to about 750 F (3150C to about 3990C), preferably about 600 F to about 700 F (3150C to about 371 *C); and pressures from about 15 to 3000 psig, preferably 100 to 2500 psig. The hydroisomerization dewaxing pressures in this context refer to the hydrogen partial pressure within the hydroisomerization reactor, 10 although the hydrogen partial pressure is substantially the same (or nearly the same) as the total pressure. The liquid hourly space velocity during contacting is generally from about 0.1 to 20 hr-1, preferably from about 0.1 to about 5 hr-1. The hydrogen to hydrocarbon ratio falls within a range from about 1.0 to about 50 moles H 2 per mole hydrocarbon, more 15 preferably from about 10 to about 20 moles H 2 per mole hydrocarbon. Suitable conditions for performing hydroisomerization are described in U.S. Patent Nos. 5,282,958 and 5,135,638, the contents of which are incorporated by reference in their entirety. 20 Hydrogen is present in the reaction zone during the hydroisomerization dewaxing process, typically in a hydrogen to feed ratio from about 0.5 to 30 MSCF/bbl (thousand standard cubic feet per barrel), preferably from about 1 to about 10 MSCF/bbl. Generally, hydrogen will be separated from the product and recycled to the reaction zone. 25 Hydrotreatinq and Hydrofinishing Hydrotreating refers to a catalytic process, usually carried out in the presence of free hydrogen, in which the primary purpose is the removal of 30 various metal contaminants, such as arsenic, aluminum, and cobalt; heteroatoms, such as sulfur and nitrogen; oxygenates; or aromatics from the feed stock. Generally, in hydrotreating operations cracking of the hydrocarbon molecules, i.e., breaking the larger hydrocarbon molecules -21- WO 2005/066319 PCT/US2004/041165 into smaller hydrocarbon molecules, is minimized, and the unsaturated hydrocarbons are either fully or partially hydrogenated. Waxy feed to the process of this invention is preferably hydrotreated prior to hydroisomerization dewaxing. 5 Catalysts used in carrying out hydrotreating operations are well known in the art. See for example U.S. Patent Nos. 4,347,121 and 4,810,357, the contents of which are hereby incorporated by reference in their entirety, for general descriptions of hydrotreating, hydrocracking, and of typical 10 catalysts used in each of the processes. Suitable catalysts include noble metals from Group VIllA (according to the 1975 rules of the International Union of Pure and Applied Chemistry), such as platinum or palladium on an alumina or siliceous matrix, and Group VillI and Group VIB, such as nickel-molybdenum or nickel-tin on an alumina or siliceous matrix. U.S. 15 Patent No. 3,852,207 describes a suitable noble metal catalyst and mild conditions. Other suitable catalysts are described, for example, in U.S. Patent Nos. 4,157,294 and 3,904,513. The non-noble hydrogenation metals, such as nickel-molybdenum, are usually present in the final catalyst composition as oxides, but are usually employed in their reduced 20 or sulfided forms when such sulfide compounds are readily formed from the particular metal involved. Preferred non-noble metal catalyst compositions contain in excess of about 5 weight percent, preferably about 5 to about 40 weight percent molybdenum and/or tungsten, and at least about 0.5, and generally about 1 to about 15 weight percent of nickel 25 and/or cobalt determined as the corresponding oxides. Catalysts containing noble metals, such as platinum, contain in excess of 0.01 percent metal, preferably between 0.1 and 1.0 percent metal. Combinations of noble metals may also be used, such as mixtures of platinum and palladium. 30 Typical hydrotreating conditions vary over a wide range. In general, the overall LHSV is about 0.25 to 2.0, preferably about 0.5 to 1.5. The hydrogen partial pressure is greater than 200 psia, preferably ranging from -22- WO 2005/066319 PCT/US2004/041165 about 500 psia to about 2000 psia. Hydrogen recirculation rates are typically greater than 50 SCF/Bb, and are preferably between 1000 and 5000 SCF/Bbl. Temperatures in the reactor will range from about 300 degrees F to about 750 degrees F (about 150 degrees C to about 400 5 degrees C), preferably ranging from 450 degrees F to 725 degrees F (230 degrees C to 385 degrees C). Hydrotreating is used as a step following hydroisomerization dewaxing in the lubricant base oil manufacturing process of this invention. This step, 10 herein called hydrofinishing, is intended to improve the oxidation stability, UV stability, and appearance of the product by removing traces of aromatics, olefins, color bodies, and solvents. As used in this disclosure, the term UV stability refers to the stability of the lubricating base oil or the finished lubricant when exposed to UV light and oxygen. Instability is 15 indicated when a visible precipitate forms, usually seen as floc or cloudiness, or a darker color develops upon exposure to ultraviolet light and air. A general description of hydrofinishing may be found in U.S. Patent Nos. 3,852,207 and 4,673,487. Clay treating to remove these impurities is an alternative final process step. 20 Fractionation: Optionally, the process of this invention may include fractionating of the substantially paraffinic wax feed prior to hydroisomerization dewaxing, or 25 fractionating of the lubricating base oil. The fractionation of the substantially paraffinic wax feed or lubricating base oil into distillate fractions is generally accomplished by either atmospheric or vacuum distillation, or by a combination of atmospheric and vacuum distillation. Atmospheric distillation is typically used to separate the lighter distillate 30 fractions, such as naphtha and middle distillates, from a bottoms fraction having an initial boiling point above about 600 degrees F to about 750 degrees F (about 315 degrees C to about 399 degrees C). At higher temperatures thermal cracking of the hydrocarbons may take place - 23 - WO 2005/066319 PCT/US2004/041165 leading to fouling of the equipment and to lower yields of the heavier cuts. Vacuum distillation is typically used to separate the higher boiling material, such as the lubricating base oil fractions, into different boiling range cuts. Fractionating the lubricating base oil into different boiling range cuts 5 enables the lubricating base oil manufacturing plant to produce more than one grade, or viscosity, of lubricating base oil. Solvent Dewaxinq: 10 Solvent dewaxing may be optionally used to remove small amounts of remaining waxy molecules from the lubricating base oil after hydroisomerization dewaxing. Solvent dewaxing is done by dissolving the lubricating base oil in a solvent, such as methyl ethyl ketone, methyl iso butyl ketone, or toluene, and precipitating the wax molecules as discussed 15 in Chemical Technology of Petroleum, 3rd Edition, William Gruse and Donald Stevens, McGraw-Hill Book Company, Inc., New York, 1960, pages 566 to 570. See also US Patents 4,477,333, 3,773,650 and 3,775,288. 20 Lubricatinq Base Oil Hydrocarbon Composition: The lubricating base oils of this invention have greater than 95 weight percent saturates as determined by elution column chromatography, ASTM D 2549-02. Olefins are present in amounts less than detectable by long duration C 1 3 Nuclear Magnetic Resonance Spectroscopy (NMR). 25 Molecules with at least one aromatic function are present in amounts less than 0.3 weight percent by HPLC-UV, and confirmed by ASTM D 5292-99 modified to measure low level aromatics. In preferred embodiments molecules with at least one aromatic function are present in amounts less than 0.10 weight percent, preferably less than 0.05 weight percent, and 30 more preferably less than 0.01 weight percent. Sulfur is present in amounts less than 25 ppm, more preferably less than 1 ppm as determined by ultraviolet fluorescence by ASTM D 5453-00. -24- WO 2005/066319 PCT/US2004/041165 Aromatics Measurement by HPLC-UV: The method used to measure low levels of molecules with at least one aromatic function in the lubricating base oils of this invention uses a Hewlett Packard 1050 Series Quaternary Gradient High Performance 5 Liquid Chromatography (HPLC) system coupled with a HP 1050 Diode Array UV-Vis detector interfaced to an HP Chem-station. Identification of the individual aromatic classes in the highly saturated lubricating base oils was made on the basis of their UV spectral pattern and their elution time. The amino column used for this analysis differentiates aromatic molecules 10 largely on the basis of their ring- number (or more correctly, double-bond number). Thus, the single ring aromatic containing molecules elute first, followed by the polycyclic aromatics in order of increasing double bond number per molecule. For aromatics with similar double bond character, those with only alkyl substitution on the ring elute sooner than those with 15 naphthenic substitution. Unequivocal identification of the various base oil aromatic hydrocarbons from their UV absorbance spectra was accomplished recognizing that their peak electronic transitions were all red-shifted relative to the pure model compound analogs to a degree dependent on the amount of alkyl and 20 naphthenic substitution on the ring system. These bathochromic shifts are well known to be caused by alkyl-group delocalization of the g -electrons in the aromatic ring. Since few unsubstituted aromatic compounds boil in the lubricant range, some degree of red-shift was expected and observed for all of the principle aromatic groups identified. 25 Quantitation of the eluting aromatic compounds was made by integrating chromatograms made from wavelengths optimized for each general class of compounds over the appropriate retention time window for that aromatic. Retention time window limits for each aromatic class were determined by manually evaluating the individual 30 absorbance spectra of eluting compounds at different times and assigning them to the appropriate aromatic class based on their -25- WO 2005/066319 PCT/US2004/041165 qualitative similarity to model compound absorption spectra. With few exceptions, only five classes of aromatic compounds were observed in highly saturated API Group 11 and Ill lubricating base oils. HPLC-UV Calibration: 5 HPLC-UV is used for identifying these classes of aromatic compounds even at very low levels. Multi-ring aromatics typically absorb 10 to 200 times more strongly than single-ring aromatics. Alkyl-substitution also affected absorption by about 20%. Therefore, it is important to use HPLC to separate and identify the various species of aromatics and know how 10 efficiently they absorb. Five classes of aromatic compounds were identified. With the exception of a small overlap between the most highly retained alkyl-1 -ring aromatic naphthenes and the least highly retained alkyl naphthalenes, all of the aromatic compound classes were baseline resolved. Integration limits for 15 the co-eluting 1-ring and 2-ring aromatics at 272nm were made by the perpendicular drop method. Wavelength dependent response factors for each general aromatic class were first determined by constructing Beers Law plots from pure model compound mixtures based on the nearest spectral peak absorbances to the substituted aromatic analogs. 20 For example, alkyl-cyclohexylbenzene molecules in base oils exhibit a distinct peak absorbance at 272nm that corresponds to the same (forbidden) transition that unsubstituted tetralin model compounds do at 268nm. The concentration of alkyl-1 -ring aromatic naphthenes in base oil samples was calculated by assuming that its molar absorptivity response 25 factor at 272nm was approximately equal to tetralin's molar absorptivity at 268nm, calculated from Beer's law plots. Weight percent concentrations of aromatics were calculated by assuming that the average molecular weight for each aromatic class was approximately equal to the average molecular weight for the whole base oil sample. -26 - WO 2005/066319 PCT/US2004/041165 This calibration method was further improved by isolating the 1-ring aromatics directly from the lubricating base oils via exhaustive HPLC chromatography. Calibrating directly with these aromatics eliminated the assumptions and uncertainties associated with the model compounds. As 5 expected, the isolated aromatic sample had a lower response factor than the model compound because it was more highly substituted. More specifically, to accurately calibrate the HPLC-UV method, the substituted benzene aromatics were separated from the bulk of the lubricating base oil using a Waters semi-preparative HPLC unit. 10 grams 10 of sample was diluted 1:1 in n-hexane and injected onto an amino-bonded silica column, a 5cm x 22.4mm ID guard, followed by two 25cm x 22.4mm ID columns of 8-12 micron amino-bonded silica particles, manufactured by Rainin Instruments, Emeryville, California, with n-hexane as the mobile phase at a flow rate of l8mls/min. Column eluent was fractionated based 15 on the detector response from a dual wavelength UV detector set at 265nm and 295nm. Saturate fractions were collected until the 265nm absorbance showed a change of 0.01 absorbance units, which signaled the onset of single ring aromatic elution. A single ring aromatic fraction was collected until the absorbance ratio between 265nm and 295nm 20 decreased to 2.0, indicating the onset of two ring aromatic elution. Purification and separation of the single ring aromatic fraction was made by re-chromatographing the monoaromatic fraction away from the "tailing" saturates fraction which resulted from overloading the HPLC column. This purified aromatic "standard" showed that alkyl substitution decreased 25 the molar absorptivity response factor by about 20% relative to unsubstituted tetralin. Confirmation of Aromatics by NMR: The weight percent of all molecules with at least one aromatic function in the purified mono-aromatic standard was confirmed via long-duration 30 carbon 13 NMR analysis. NMR was easier to calibrate than HPLC UV because it simply measured aromatic carbon so the response did not - 27 - WO 2005/066319 PCT/US2004/041165 depend on the class of aromatics being analyzed. The NMR results were translated from % aromatic carbon to % aromatic molecules (to be consistent with HPLC-UV and D 2007) by knowing that 95-99% of the aromatics in highly saturated lubricating base oils were single-ring 5 aromatics. High power, long duration, and good baseline analysis were needed to accurately measure aromatics down to 0.2% aromatic molecules. More specifically, to accurately measure low levels of all molecules with at least one aromatic function by NMR, the standard D 5292-99 method was 10 modified to give a minimum carbon sensitivity of 500:1 (by ASTM standard practice E 386). Al 5-hour duration run on a 400-500 MHz NMR with a 10 12 mm Nalorac probe was used. Acorn PC integration software was used to define the shape of the baseline and consistently integrate. The carrier frequency was changed once during the run to avoid artifacts from imaging 15 the aliphatic peak into the aromatic region. By taking spectra on either side of the carrier spectra, the resolution was improved significantly. Cycloparaffin Distribution by FlMS: Paraffins are considered more stable than cycloparaffins towards oxidation, and therefore, more desirable. Monocycloparaffins are 20 considered more stable than multicycloparaffins towards oxidation. However, when the weight percent of all molecules with at least one cycloparaffin function is very low in a lubricating base oil, the additive solubility is low and the elastomer compatibility is poor. Examples of base oils with these properties are polyalphaolefins and Fischer-Tropsch base 25 oils with less than about 5% cycloparaffins. To improve these properties in finished lubricants, expensive co-solvents such as esters must often be added. There is achieved by this invention lubricating base oils with a high weight percent of molecules containing monocycloparaffins and a low weight percent of molecules containing multicycloparaffins such that they 30 have high oxidation stability and high viscosity index in addition to good additive solubility and elastomer compatibility. -28 - WO 2005/066319 PCT/US2004/041165 The distribution of the saturates (n-paraffin, iso-paraffin, and cycloparaffins) in lubricating base oils of this invention is determined by field ionization mass spectroscopy (FIMS). FIMS spectra were obtained on a VG 70VSE mass spectrometer. The samples were introduced via a 5 solid probe, which was heated from about 400C to 5000C at a rate of 500C per minute. The mass spectrometer was scanned from m/z 40 to m/z 1000 at a rate of 5 seconds per decade. The acquired mass spectra were summed to generate one "averaged" spectrum. Each spectrum was C13 corrected using a software package from PC-MassSpec. FIMS ionization 10 efficiency was evaluated using blends of nearly pure branched paraffins and highly naphthenic, aromatics-free base stock. The ionization efficiencies of iso-paraffins and cycloparaffins in these base oils were essentially the same. Iso-paraffins and cycloparaffins comprise more than 99.9% of the saturates in the lubricating base oils of this invention. 15 The lubricating base oils of this invention are characterized by FIMS into paraffins and cycloparaffins containing different numbers of rings. Monocycloparaffins contain one ring, dicycloparaffins contain two rings, tricycloparaffins contain three rings, tetracycloparaffins contain four rings, 20 pentacycloparaffins contain five rings, and hexacycloparaffins contain six rings. Cycloparaffins with more than one ring are referred to as multicycloparaffins in this invention. In one embodiment, the lubricating base oils of this invention have a 25 weight percent of all molecules with at least one cycloparaffin function greater than 10, preferably greater than 15, more preferably greater than 20. They have a ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater than 15, preferably greater than 50, more 30 preferably greater than 100. The most preferred lubricating base oils of this invention have a weight percent of molecules containing monocycloparaffins greater than 10, and a weight percent of molecules containing multicycloparaffins less than 0.1, or even no molecules -29 - WO 2005/066319 PCT/US2004/041165 containing multicycloparaffins. In this embodiment, the lubricating base oils may have a kinematic viscosity at 100*C between about 2 cSt and about 20 cSt, preferably between about 2 cSt and about 12 cSt, most preferably between about 3.5 cSt and about 12 cSt. 5 In another embodiment of this invention there is a relationship between the weight percent of all molecules with at least one cycloparaffin function and the kinematic viscosity of the lubricating base oils of this invention. That is, the higher the kinematic viscosity at 100 C in cSt the higher the amount of 10 all molecules with at least one cycloparaffin function that are obtained. In a preferred embodiment the lubricating base oils have a weight percent of all molecules with at least cycloparaffin function greater than the kinematic viscosity in cSt multiplied by three, preferably greater than 15, more preferably greater than 20; and a ratio of weight percent of molecules 15 containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater than 15, preferably greater than 50, more preferably greater than 100. The lubricating base oils have a kinematic viscosity at 100 C between about 2 cSt and about 20 cSt, preferably between about 2 cSt and about 12 cSt. Examples of these base oils may 20 have a kinematic viscosity at 100*C of between about 2 cSt and about 3.3 cSt and have a weight percent of all molecules with at least one cycloparaffin function that is very high, but less than 10 weight percent. The modified ASTM D 5292-99 and HPLC-UV test methods used to 25 measure low level aromatics, and the FIMS test method used to characterize saturates are described in D.C. Kramer, et al., "Influence of Group II & Ill Base Oil Composition on VI and Oxidation Stability," presented at the 1999 AlChE Spring National Meeting in Houston, March 16, 1999, the contents of which is incorporated herein in its entirety. 30 Although the wax feeds of this invention are essentially free of olefins, base oil processing techniques can introduce olefins, especially at high -30 - WO 2005/066319 PCT/US2004/041165 temperatures, due to 'cracking' reactions. In the presence of heat or UV light, olefins can polymerize to form higher molecular weight products that can color the base oil or cause sediment. In general, olefins can be removed during the process of this invention by hydrofinishing or by clay 5 treatment. Base Oil Pour Factor In preferred embodiments, the lubricating base oils of this invention have a 10 ratio of pour point in degrees Celsius to kinematic viscosity at 100 C in cSt greater than the Base Oil Pour Factor of said lubricating base oil. The Base Oil Pour Factor is a function of the kinematic viscosity at 100 C and is calculated by the following equation: Base Oil Pour Factor = 7.35 x Ln(Kinematic Viscosity at 100 C) - 18, where Ln(Kinematic Viscosity) is 15 the natural logarithm with base "e" of the kinematic viscosity at 100*C measured in centistoke (cSt). The test method used to measure pour point is ASTM D 5950-02. The pour point is determined in one degree increments. The test method used to measure the kinematic viscosity is ASTM D 445-01. We show a plot of this equation in Figure 1. 20 This relationship of pour point and kinematic viscosity in preferred embodiments of this invention also defines the preferred lower limit of pour point in degrees Celsius for each oil viscosity. For preferredexamples of the lubricating base oils of this invention, the lower limit of pour point at a 25 given kinematic viscosity at 100 C = Base Oil Pour Factor x Kinematic Viscosity at 100"C. Thus the lower limit of pour point for a preferred 2.5 cSt lubricating base oil would be -280C, for a preferred 4.5 cSt lubricating base oil would be -31 C, for a preferred 6.5 cSt lubricating base oil would be -28*C, and for a preferred 10 cSt lubricating base oil would be -11 C. 30 By selecting for moderately low pour points we have oils that are not over dewaxed that can be produced in high yields. In most cases the pour points of the lubricating base oils of this invention will be between -350C and +100C. -31- WO 2005/066319 PCT/US2004/041165 In preferred embodiments, the high ratio of pour point to kinematic viscosity at 100 C controls the pour point into a range that is moderately low, thus not requiring severe dewaxing. The severe dewaxing required to 5 produce lubricating base oils with high cycloparaffins and very low pour points in the prior art decreased the ratio of monocycloparaffins to multicycloparaffins, and perhaps most importantly reduced the total yield of lubricating base oil and finished lubricant produced. 10 There is not necessarily a relationship between the Base Oil Pour Factor and desired cycloparaffin composition between base oils made by different manufacturing processes. Each desired property of the lubricating base oil of this invention should be selected for independently until a relationship may be determined for a specific manufacturing process. 15 The base oils of this invention respond favorably to the addition of conventional pour point depressants. Due to this favorable interaction it is not necessary to over dewax them to very low pour points at a yield disadvantage. With the addition of pour point depressant they may be 20 blended into products meeting severe requirements for good low temperature properties, such as automotive engine oils. Other Lubricating Base Oil Properties 25 Viscosity Index: The viscosity indexes of the lubricating base oils of this invention will be high. In a preferred embodiment they will have viscosity indexes greater than 28 x Ln(Kinematic Viscosity at I 00*C) +95. For example a 4.5 cSt oil 30 will have a viscosity index greater than 137, and a 6.5 cSt oil will have a viscosity index greater than 147. In another preferred embodiment the viscosity indexes will be greater than 28 x Ln(Kinematic Viscosity at -32 - WO 2005/066319 PCT/US2004/041165 100*C) + 110. The test method used to measure viscosity index is ASTM D 2270-93(1998). Aniline Point: 5 The aniline point of a lubricating base oil is the temperature at which a mixture of aniline and oil separates. ASTM D 611-01 b is the method used to measure aniline point. It provides a rough indication of the solvency of the oil for materials which are in contact with the oil, such as additives and 10 elastomers. The lower the aniline point the greater the solvency of the oil. Prior art lubricating base oils with a weight percent of all molecules with at least one aromatic function less than 0.30, made from substantially paraffinic wax feed having less than about 30 ppm total combined nitrogen and sulfur and hydroisomerization dewaxing, tend to have high aniline 15 points and thus poor additive solubility and elastomer compatibility. The higher amounts of all molecules with at least one cycloparaffin function in the lubricating base oils of this invention reduce the aniline point and thus improve the additive solubility and elastomer compatibility. The aniline point of the lubricating base oils of this invention will tend to vary 20 depending on the kinematic viscosity of the lubricating base oil at 100 C in cSt. In a preferred embodiment, the aniline point of the lubricating base oils of this invention will be less than a function of the kinematic viscosity at 25 100 C. Preferably, the function for aniline point is expressed as follows: Aniline Point, *F s 36 x Ln (Kinematic Viscosity at 100 C) + 200. A plot of this equation is shown in FIGURE 2. -33- WO 2005/066319 PCT/US2004/041165 Oxidation Stability: Due to the extremely low aromatics and multicycloparaffins in the lubricating base oils of this invention their oxidation stability exceeds that 5 of most lubricating base oils. A convenient way to measure the stability of lubricating base oils is by the use of the Oxidator BN Test, as described by Stangeland et al. in U.S. Patent 3,852,207. The Oxidator BN test measures the resistance to 10 oxidation by means of a Dornte-type oxygen absorption apparatus. See R. W. Dornte "Oxidation of White Oils," Industrial and Engineering Chemistry, Vol. 28, page 26, 1936. Normally, the conditions are one atmosphere of pure oxygen at 340*F. The results are reported in hours to absorb 1000 ml of 02 by 100 g. of oil. In the Oxidator BN test, 0.8 ml of 15 catalyst is used per 100 grams of oil and an additive package is included in the oil. The catalyst is a mixture of soluble metal naphthenates in kerosene. The mixture of soluble metal naphthenates simulates the average metal analysis of used crankcase oil. The level of metals in the catalyst is as follows: Copper = 6,927 ppm ; Iron = 4,083 ppm ; Lead = 20 80,208 ppm; Manganese= 350ppm ; Tin= 3565 ppm. The additive package is 80 millimoles of zinc bispolypropylenephenyldithio-phosphate per 100 grams of oil, or approximately 1.1 grams of OLOA 260. The Oxidator BN test measures the response of a lubricating base oil in a simulated application. High values, or long times to absorb one liter of 25 oxygen, indicate good oxidation stability. Traditionally it is considered that the Oxidator BN should be above 7 hours. For the present invention, the Oxidator BN value will be greater than about 30 hours, preferably greater than about 40 hours. 30 OLOA is an acronym for Oronite Lubricating Oil Additive@, which is a registered trademark of Chevron Oronite. -34- WO 2005/066319 PCT/US2004/041165 Noack Volatility: Another important property of the lubricating base oils of this invention is low Noack volatility. Noack volatility is defined as the mass of oil, 5 expressed in weight percent, which is lost when the oil is heated at 250 degrees C and 20 mmHg (2.67 kPa; 26.7 mbar) below atmospheric in a test crucible through which a constant flow of air is drawn for 60 minutes (ASTM D 5800). A more convenient method for calculating Noack volatility and one which correlates well with ASTM D-5800 is by using a thermo 10 gravimetric analyzer test (TGA) by ASTM D 6375-99a. TGA Noack volatility is used throughout this disclosure unless otherwise stated. In preferred embodiments, the lubricating base oils of this invention have a Noack volatility less than an amount calculated from the equation: Noack 15 Volatility, Wt% = 1000 x (Kinematic Viscosity at 1 00C)2.7, preferably less than an amount calculated from the equation: Noack Volatility, Wt% = 900 x (Kinematic Viscosity at 1 OOOC)2a. Plots of these equations are shown in FIGURE 3. 20 CCS Viscosity: The lubricating base oils of this invention also have excellent viscometric properties under low temperature and high shear, making them very useful in multigrade engine oils. The cold-cranking simulator apparent viscosity 25 (CCS VIS) is a test used to measure the viscometric properties of lubricating base oils under low temperature and high shear. The test method to determine CCS VIS is ASTM D 5293-02. Results are reported in centipoise, cP. CCS VIS has been found to correlate with low temperature engine cranking. Specifications for maximum CCS VIS are 30 defined for automotive engine oils by SAE J300, revised in June 2001. -The CCS VIS measured at -350C of the lubricating base oils of this invention are low, preferably less than an amount calculated by the equation: CCS VIS (-35'C), cP = 38 x (Kinematic Viscosity at I 00C)3, - 35 - WO 2005/066319 PCT/US2004/041165 more preferably less than an amount calculated by the equation: CCS VIS (-35 0 C), cP = 38 x (Kinematic Viscosity at 100. C) 28 . Plots of these equations are shown in FIGURE 4. 5 Elastomer Compatibility: Lubricating base oils come into direct contact with seals, gaskets, and other equipment components during use. Original equipment manufacturers and standards setting organizations set elastomer 10 compatibility specifications for different types of finished lubricants. Examples.of elastomer compatibility tests are CEC-L-39-T-96, and ASTM D 4289-03. An ASTM standard entitled "Standard Test Method and Suggested Limits of Determining the Compatibility of Elastomer Seals for Industrial Hydraulic Fluid Applications" is currently in development. 15 Elastomer compatibility test procedures involve suspending a rubber specimen of known volume in the lubricating base oil or finished lubricant under fixed conditions of temperature and test duration. This is followed at the end of the test by a second measurement of the volume to determine the percentage swell that has occurred. Additional measurements may be 20 made of the changes in elongation at break and tensile strength. Depending on the rubber type and application, the test temperature may vary significantly. In preferred embodiments, the lubricating base oils of this invention are compatible with a broad number of types of elastomers, including but not limited to the following: neoprene, nitrile (acrylonitrile 25 butadiene), hydrogenated nitrile, polyacrylate, ethylene-acrylic, silicone, chlor-sulfonated polyethylene, ethylene-propylene copolymers, epichlorhydrin, fluorocarbon, perfluoroether, and PTFE. All of the publications, patents and patent applications cited in this 30 application are herein incorporated by reference in their entirety to the same extent as if the disclosure of each individual publication, patent application or patent was specifically and individually indicated to be incorporated by reference in its entirety. - 36 - WO 2005/066319 PCT/US2004/041165 EXAMPLES The following examples are included to further clarify the invention but are 5 not to be construed as limitations on the scope of the invention. Fischer-Tropsch Wax Two commercial samples of hydrotreated Fischer-Tropsch wax made 10 using a Fe-based Fischer-Tropsch synthesis catalyst (WOW8684 and . NGQ9989) and three samples of hydrotreated Fischer-Tropsch wax made using a Co-based Fischer-Tropsch catalyst (WOW8782, WOW9107, and WOW9237) were analyzed and found to have the properties shown in Table 1. -37 - WO 2005/066319 PCT/US2004/041165 Table I Fischer-Tropsch Wax Fischer- Fe- Fe- Co- Co- Co Tropsch Based Based Based Based Based Catalyst CVX WOW8684 NGQ9989 WOW8782 WOW9107 WOW9237 Sample ID Sulfur, ppm 7, <2 <6 2 Nitrogen, 2,4,4,1 12,19 6,5 1.3 ppm ,4,7 Oxygen by 0.15 0.69 0.59 0.11 NA, Wt% GC N-Paraffin Analysis Total N Paraffin, Wt% 92.15 83.72 84.47 Avg. Carbon Number 41.6 30.7 27.3 Avg. Molecular 585.4 432.5 384.9 Weight _ D 6352 SIMDIST TBP (WT%), "F TO.5 784 10 129 515 450 T5 853 131 568 597 571 T10 875 181 625 639 621 T20 914 251 674 689 683 T30 941 309 717 714 713 T40 968 377 756 751 752 T50 995 437 792 774 788 T60 1013 497 827 807 823 T70 1031 553 873 839 868 T80 1051 611 914 870 911 T90 1081 674 965 911 970 T95 1107 707 1005 935 1003 T99.5 1133 744 1090 978 1067 T90-TI0, 97 256 171 133 176 0 C Wt% C30+ 96.9 0.00 40.86 34.69 39.78 Wt% C60+ 0.55 0.00 0.00 0.00 0.00 C60+/C30+ 0.01 0.00 0.00 0.00 0.00 The Fischer-Tropsch wax feeds were hydroisomerized over a Pt/SSZ-32 5 catalyst or Pt/SAPO-1 I catalyst on an alumina binder. Run conditions - 38 - WO 2005/066319 PCT/US2004/041165 were between 652 and 695 "F (344 and 368 0C), 0.6 to 1.0 LHSV, 300 psig or 1000 psig reactor pressure, and a once-through hydrogen rate of between 6 and 7 MSCF/bbl. For the majority of the samples the reactor effluent passed directly to a second reactor, also at 1000 psig, which 5 contained a Pt/Pd on silica-alumina hydrofinishing catalyst. Conditions in that reactor were a temperature of 450 "F and LHSV of 1.0. Those samples which were not hydrofinished are indicated in the tables of properties that follow. 10 The products boiling above 650'F were fractionated by atmospheric or vacuum distillation to produce distillate fractions of different viscosity grades. Test data on specific distillate fractions useful as lubricating base oils of this invention, and comparison samples, are shown in the following examples. 15 Lubricating Base Oils Example 1, Example 2, and Comparative Example 3: 20 Three lubricating base oils with kinematic viscosities below 3.0 cSt at 100 C were prepared by hydroisomerization dewaxing Fischer-Tropsch wax and fractionating the isomerized oil into different distillate fractions. The properties of these samples are shown in Table 11. - 39 - WO 2005/066319 PCT/US2004/041165 Table 11 Properties Example 1 Example 2 Comparative Example 3 CVX Sample ID PGQ0118 PGQ0117 NGQ9637 Wax Feed NGQ9989 NGQ9989 WOW9107 Hydroisomerization 681 681 671 Temp, *F Hydroisomerization Pt/SAPO-1 I Pt/SAPO-1 1 Pt/SAPO-1 1 Dewaxing Catalyst Reactor Pressure, 1000 1000 1000 psig Viscosity at 100 C, cSt 2.981 2.598 2.297 Viscosity Index 127 124 124 Aromatics, wt% 0.0128 0.0107 FIMS, Wt% of Molecules Paraffins 89.2 91.1 91.3 Monocycloparaffins 10.8 8.9 8.0 Multicycloparaffins 0.0 0.0 0.7 Total 100.0 100.0 100.0 API Gravity 43.4 44.1 44.69 Pour Point, 0 C -27 -32 -33 Cloud Point, *C -18 -22 -7 Ratio of >100 >100 11.4 Mono/Multicycloparaffins Ratio of Pour -9.1 -12.3 -14.4 Point/Vis100 Base Oil Pour Factor -9.97 -10.98 -11.89 Aniline Point, D 611, *F 236.5 226.3 Noack Volatility, Wt% 32.48 49.18 CCS Viscosity @-35 *C, cP <900 <900 <900 Example 1 and Example 2 have low weight percents of all molecules with at least one aromatic function, high weight percents of all molecules with 5 at least one cycloparaffin function, and a very high ratio of weight percent of molecules containing monocycloparaffins and weight percent of molecules containing multicycloparaffins. Note that Example I does not have greater than 10 weight percent of all molecules with at least one cycloparaffin function, but it does have a weight percent of all molecules 10 with at least one cycloparaffin function greater than the kinematic viscosity at 1 00*C multiplied by three. Example I also has a high ratio of pour point to kinematic viscosity at 1 00*C, meeting the properties of a preferred lubricating base oil of this invention. In addition the aniline points of -40- WO 2005/066319 PCT/US2004/041165 Examples 1 and 2 fall below the line given by: 36 x Ln(Kinematic Viscosity at 100*C) + 200. Comparative Example 3 has a slightly lower weight percent of all molecules with at least one cycloparaffin function. Comparative Example 3 also has a less desirable ratio of weight percent 5 of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins, and a less preferred lower ratio of pour point to kinematic viscosity. These examples demonstrate that a low viscosity lubricating base oil of this invention, with a kinematic viscosity at 100*C between 2 and about 3,3 cSt, may have less than 10 weight 10 percent of all molecules with at least one cycloparaffin function, but a weight percent of all molecules with at least one cycloparaffin function greater than 3 times the kinematic viscosity at 100C. Example 4, Example 5, Example 6, and Example 7: 15 Four lubricating base oils with kinematic viscosities between 4.0 and 5.0 cSt at 100*C were prepared by hydroisomerization dewaxing Fischer Tropsch wax and fractionating the isomerized oil into different distillate fractions. The properties of these samples are shown in Table Ill. 20 -41 - WO 2005/066319 PCT/US2004/041165 Table IlIl Properties Example 4 Example 5 Example 6 Example 7 CVX Sample ID NGQ9712 PGQ1 118 NGQ9608 NGQ9939 Wax Feed WOW9107 WOW9237 WOW878 WOW8684 2 Hydroisomerization 673 652 700 682 Temp, *F Hydroisomerization Pt/SAPO-1 1 Pt/SAPO-1 1 Pt/SAPO-1 1 Pt/SAPO-1 1 Dewaxing Catalyst Reactor Pressure, psig 1000 300 1000 1000 Viscosity at 100*C, cSt 4.104 4.397 4.415 4.524 Viscosity Index 145 158 147 149 Aromatics, wt% 0.0086 0.0109 FIMS, Wt% OF Molecules Paraffins 88.4 79.8 89.1 89.4 Monocycloparaffins 11.6 21.2 10.9 10.4 Multicycloparaffins 0.0 0.0 0.0 0.2 Total 100.0 100.0 100.0 100.0 API Gravity 41.78 41.6 Pour Point, *C -20 -31 -12 -17 Cloud Point, *C -9 +3 -8 -10 Ratio of >100 >100 >100 52 Mono/Multicycloparaffins Ratio of Pour Point/Vis100 -4.87 -7.05 -2.72 -3.76 Base Oil Pour Factor -7.62 -7.12 -7.09 -6.91 Oxidator BN, Hours 40.78 26.0 41.35 34.92 Aniline Point, D 611, *F 249.6 253.2 Noack Volatility, Wt% 14.43 10.89 12.53 CCS Viscosity @ -35C, cP 1662 2079 2090 -42- WO 2005/066319 PCT/US2004/041165 Examples 4, 5, 6, and 7 all had the desired properties of the lubricating base oils of this invention. Examples 4 and 7 had exceptionally high oxidation stabilities, greater than 40 hours. Examples 4 and 7 also had 5 low aniline points, which would provide desirable additive solubility and elastomer compatibility. Example 8, Comparative Example 9, Example 10, and Example 11: 10 Four lubricating base oils with kinematic viscosities between 6.0 and 7.0 at 100*C were prepared by hydroisomerization dewaxing Fischer-Tropsch wax and fractionating the isomerized oil into different distillate fractions. The properties of these samples are shown in Table IV. -43 - WO 2005/066319 PCT/US2004/041165 Table IV Properties Example 8 Comparative Example 10 Example 11 Example 9* CVX Sample ID NGQ9994 NGQ9289 NGQ9941 NGQ9988 Wax Feed WOW8684 WOW8684 WOW8684 WOW8684 Hydroisomerization 676 685 690 681 Temp, *F Hydroisomerization Pt/SAPO-1 1 Pt/SSZ-32* Pt/SAPO-1 1 Pt/SAPO-1 I Dewaxing Catalyst Reactor Pressure, psig 1000 1000 1000 1000 Viscosity at 1 00*C, cSt 6.26 6.972 6.297 6.295 Viscosity Index 158 153 153 154 Aromatics, wt% 0.0898 0.0141 FIMS, Wt% of Molecules Paraffins 77.0 71.4 82.5 76.8 Monocycloparaffins 22.6 26.4 17.5 22.1 Multicycloparaffins 0.4 2.2 0.0 1.1 Total 100.0 100.0 100.0 100.0 API Gravity 40.3 40.2 40.2 Pour Point, *C -12 -41 -23 -14 Cloud Point, *C -1 -2 -6 -6 Ratio of 56.5 12.0 >100 20.1 Mono/Multicycloparaffins Ratio of Pour -1.92 -5.89 -3.65 -2.22 Point/Vis100 Base Oil Pour Factor -4.52 -3.73 -4.48 -4.48 Aniline Point, D611, *F 263 Noack Volatility, Wt% 2.3 5.5 2.8 3.19 CCS Vis @ -35C, cP 5770 5993 4868 5002 * not hydrofinished -44 - WO 2005/066319 PCT/US2004/041165 Examples 8, 10, and 11 are examples of lubricating base oils of this invention. Comparative Example 9 has a low ratio of molecules containing monocycloparaffins to molecules containing multicycloparaffins. In this comparative example, hydroisomerization dewaxing to produce a base oil 5 with very low pour point was done with a yield disadvantage, and likely adversely impacted the ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins. Comparative Example 9 also had a higher Noack Volatility than the other oils of similar viscosity. Examples 8, 10, and 11 all 10 had very low CCS VIS at -35'C, well below the amount calculated by 38 x Ln(Kinematic Viscosity.at 100"C)2. Example 12, Comparative Example 13, Example 14, and Example 15: 15 Four lubricating base oils with kinematic viscosities between 7.0 and 8.0 cSt at 100 C were prepared by hydroisomerization dewaxing Fischer Tropsch wax and fractionating the isomerized oil into different distillate fractions. The properties of these samples are shown in Table V. -45- WO 2005/066319 PCT/US2004/041165 Table V Properties Example Comparative Example Example 12 Example 13 14 15 CVX Sample ID NGQ9287 NGQ9288 NGQ9284 NGQ9535 Wax Feed WOW8684 WOW8684 WOW8684 WOW8782 Hydroisomerization 679 685 674 694 Temp, *F Hydroisomerization Pt/SSZ-32 Pt/SSZ-32 Pt/SSZ-32 Pt/SAPO-11 Dewaxing Catalyst Reactor Pressure, psig 1000 1000 1000 1000 Viscosity at 100*C, cSt 7.182 7.023 7.468 7.953 Viscosity Index 159 155 170 165 Aromatics, wt% 0.0056 0.0037 0.0093 FIMS, Wt% of Molecules Paraffins 71.3 69.0 81.4 87.2 Monocycloparaffins 27.1 28.4 18.6 12.6 Multicycloparaffins 1.6 2.6 0.0 0.2 Total 100.0 100.0 100.0 100.0 API Gravity 39.62 Pour Point, *C -27 -33 -9 -12 Cloud Point, *C +6 -4 +10 +13 Ratio of 16.9 10.9 >100 61 Mono/Multicycloparaffins Ratio of Pour Point/Visl 00 -3.76 -4.70 -1.21 -1.51 Base Oil Pour Factor -3.51 -3.67 -3.22 -2.76 Noack Volatility 4.9 5.4 4.3 2.72 CCS Vis @ -35C, cP 5873 5966 7379 13627 -46 - WO 2005/066319 PCT/US2004/041165 Example 14 is a lubricating base oil of this invention with a particularly high viscosity index, greater than 28*Ln(Visl 00) + 110, and a particularly low CCS VIS at -350C. Examples 12 and 15 also met the properties of this invention, although Example 15 did not meet the more preferred range of 5 CCS viscosity at -35*C (less than an amount calculated from the equation: CCS VIS(-35 0 C) = 38 x (Kinematic Viscosity at 1 00,C) 3 . Comparative Example 13 did not meet the properties of this invention due to a low ratio of weight percent of molecules containing monocycloparaffins and weight percent of molecules containing multicycloparaffins. This may have 10 occurred as a result of hydroisomerization dewaxing to a lower pour point in this example, which resulted in the formation of more multicycloparaffins. Example 16: 15 A lubricating base oil with a kinematic viscosity between 9.5 and 10.0 cSt at 1000C was prepared by hydroisomerization dewaxing Fischer-Tropsch wax and fractionating the isomerized oil into different distillate fractions. The properties of this sample are shown in Table VI. -47 - WO 2005/066319 PCT/US2004/041165 Table VI Properties Example 16 CVX Sample ID PGQ0144 Wax Feed WOW8684 Hydroisomerization Temp, 669 OF Hydroisomerization Pt/SAPO-1 1 Dewaxing Catalyst Reactor Pressure, psig 1000 Viscosity at 100*C, cSt 9.679 Viscosity Index- 168 FIMS, Wt% of Molecules Paraffins 84.4 Monocycloparaffins 14.7 Multicycloparaffins 0.9 Total 100.0 Pour Point, 0C +1 Cloud Point, *C +26 Ratio of 16.3 Mono/Multicycloparaffins Ratio of Pour Point/Vis100 0.10 Base Oil Pour Factor -1.32 Oxidator-BN, hours 34.64 Aniline Point, D61 1, OF 280.3 Noack Volatility 0.9 Example 16 met the properties of the lubricating base oil of this invention, including high oxidation stability, low aniline point, and low Noack volatility. 5 The Noack Volatility is less than the amount calculated from the equation: Noack Volatility, Wt% = 900 x (Kinematic Viscosity at I 00C)28. -48 - WO 2005/066319 PCT/US2004/041165 Comparative Example 17 (Run 951-15): A hydrotreated Fischer-Tropsch wax (Table VI) was isomerized over a Pt/SSZ-32 catalyst which contained 0.3% Pt and 35% Catapal alumina 5 binder. Run conditions were 560 "F hydroisomerization temperature, 1.0 LHSV, 300 psig reactor pressure, and a once-through hydrogen rate of 6 MSCF/bbl. The reactor effluent passed directly to a second reactor, also at 300 psig, which contained a Pt/Pd on silica-alumina hydrofinishing catalyst. Conditions in that reactor were a temperature of 450 OF and 10 LHSV of 1.0. Conversion and yields, as well as the properties of the hydroisomerized stripper bottoms are given in Table VIII. Table VII 15 Inspections of Hydrotreated Fischer-Tropsch Wax Gravity, API 40.3 Nitrogen, ppm 1.6 Sulfur, ppm 2 20 Sim. Dist., Wt%, OF IBP/5 512/591 10/30 637/708 50 764 25 70/90 827/911 95/FBP 941/1047 -49 - WO 2005/066319 PCT/US2004/041165 Table VIII Isomerization of FT Wax over Pt/SSZ-32 at 560 *F, I LHSV, 300 psig, and 6 MSCF/bbl H2 5 Conversion <650 OF, Wt% 15.9 Conversion <700 *F, Wt% 14.1 Yields, Wt% C1-C2 0.11 10 C3-C4 1.44 C5-180 *F 1.89 180-290 "F 2.13 290-650 *F 21.62 650 OF+ 73.19 15 Stripper Bottoms: Yield, Wt% of Feed 75.9 20 Sim. Dist., LV%, *F IBP/5 588/662 30/50 779/838 95/99 1070/1142 25 Pour Point, *C +25 The stripper bottoms were solvent dewaxed using MEK/toluene at -15 C. The wax content was 33.9 wt%, and oil yield was 65.7 wt%. The solvent 30 dewaxed 650 'F+ oil yield, based on feed to the process, was 49.9 wt%. Inspections on this lubricating base oil are given below in Table IX. - 50 - WO 2005/066319 PCT/US2004/041165 Table IX Inspections of Hydroisomerized FT Wax after Solvent Dewaxing Comparative Example 17 Identification 951-15 (455 479) CVX Sample ID PGQII18 Viscosity Index 175 Viscosity at 1000C, cSt 3.776 Pour Point, 0C -18 Cloud Point, 0 C -5 Sim. Dist., LV%, OF IBP/5 608/652 10/30 670/718 50 775 70/90 890/953 95/FBP 1004/1116 FIMS, Wt% of Molecules Paraffins 96 Monocycloparaffins 4 Multicycloparaffins 0 Total 100 Oxidator BN, Hours 31.87 Ratio of >100 Mono/Multicycloparaffins Ratio of Pour Point/VisI 00 -4.77 5 Comparative Example 17 demonstrates that mild hydroisomerization dewaxing and subsequent solvent dewaxing produced a very low weight percent of all molecules with at least one cycloparaffin function. The hydroisomerization temperature was well below the desired range of about 600OF to about 750 0 F. Although the Oxidator BN and the viscosity index -9515- WO 2005/066319 PCT/US2004/041165 of this oil was very high it would not have the preferred additive solubility and elastomer compatibility properties associated with the lubricating base oils of this invention with higher weight percents of all molecules with at least one cycloparaffin function. This example also points out that the 5 Base Oil Pour Factor, although often associated with oils that meet the properties of the lubricating base oils of this invention can not be used independently of the other criteria (weight percent of all molecules with at least one cycloparaffin function and ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing 10 multicycloparaffins, or high weight percent of molecules containing monocycloparaffins and low weight percent of molecules containing multicycloparaffins) to characterize the lubricating base oils of this invention. 15 Comparative Example 18 (Run 952-12): An n-C36 feed (purchased from Aldrich) was isomerized over a Pt/SSZ-32 catalyst which contained 0.3% Pt and 35% Catapal alumina binder. Run conditions were hydroisomerization temperature of 580 'F, 1.0 LHSV, 20 1000 psig reactor pressure, and a once-through hydrogen rate of 7 MSCF/bbl. The reactor effluent passed directly to a second reactor, also at 1000 psig, which contained a Pt/Pd on silica-alumina hydrofinishing catalyst. Conditions in that reactor were a temperature of 450 'F and LHSV of 1.0. Conversion and yields were as shown in Table X: 25 -52- WO 2005/066319 PCT/US2004/041165 Table X Conversion <650 OF, Wt% 32.2 Conversion <700 "F, Wt% 34.4 Yields, Wt% C1-C2 0.45 C3-C4 5.16 C5-180 *F 6.22 180-350 "F 7.40 350-650"F 13.23 650 *F+ 68.09 The hydroisomerized stripper bottoms from Run 952-12 had a pour point 5 of +200C. The stripper bottoms were solvent dewaxed using MEK/toluene at -15 *C. The wax content was 31.5 wt%, and oil yield was 68.2 wt%. The solvent dewaxed 650 *F+ oil yield, based on feed to the process, was 45.4 wt%. Inspections on this oil are summarized in Table Xl. 10 Comparative Example 19 (Run FSL9497): Run FSL9497 produced a lubricating base oil made from n-C28 feed (purchased from Aldrich) using a Pt/SSZ-32 catalyst (0.3 wt% Pt) bound with 35 wt% Catapal alumina. The run was at 1000 psig, 0.8 LHSV, and 7 MSCF/bbI once-through H2. Reactor hydroisomerization temperature was 15 575 OF. The effluent from the reactor was subsequently passed over a Pt Pd/SiO2-AI203 hydrofinishing catalyst at 450 OF and, other than temperature, the same conditions were used as in the isomerization - 53 - WO 2005/066319 PCT/US2004/041165 reactor. The yield of 600 'F+ product was 71.5 wt%. The conversion of the wax to 600*F- boiling range material was 28.5 wt%. The conversion below 700 OF was 33.6 wt%. The bottoms fraction from the run (75.2 wt%) was cut at 743 *F to give 89.2 wt% bottoms (67.1 wt% on the whole feed). 5 The hydroisomerized stripper bottoms had a pour point of +3'C. These bottoms were then solvent dewaxed at -15 0C to give 84.2 wt% solvent dewaxed oil (56.5 wt% on the whole feed), and 15.7 wt% wax. Inspections of the oil are shown in Table XI. 10 Table XI Properties Comparative Comparative Example 18 Example 19 CVX Sample ID PGQ1110 PGQ1112 Wax Feed n-C36 n-C28 Viscosity at 100"C, cSt 5.488 3.447 Viscosity Index 182 165 FIMS, Wt% of Molecules Paraffins 98.3 100 Monocycloparaffins 1.7 0.0 Multicycloparaffins 0.0 0.0 Total 100.0 100.0 Pour Point, 0C -9 -15 Aniline Point, D611, *F 261.9 245.1 Neither Comparative Example 18 nor Comparative Example 19 met the properties of this invention as they had very low weight percents of all 15 molecules with at least one cycloparaffin function. Neither of these base oils with low cycloparaffin content had aniline points as low as the base oils of this invention. Notably, they were both greater than 36 x Ln(Kinematic Viscosity at 1000C) + 200, in OF. These oils would be expected to have lower additive solubility and less desirable elastomer 20 compatibility than the base oils of this invention. The hydroisomerization -54- WO 2005/066319 PCT/US2004/041165 temperature was lower than the preferred range of about 600 F to 750 F, which likely contributed to the lower amounts of cycloparaffins in both of these comparative examples. 5 Comparative Example 20 and Comparative Example 21: Two commercial Group Ill lubricating base oils were prepared using a waxy petroleum feed. The waxy petroleum feed had greater than about 30 ppm total combined nitrogen and sulfur and had a weight percent oxygen less than about 0.1. The feed was dewaxed by hydroisomerization dewaxing using 10 Pt/SSZ-32 at a hydroisomerization dewaxing temperature between about 650'F (3430C) and-about 725 0 F (385"C). They were both hydrofinished. The properties of these two samples are shown in Table XII. Table XI Properties Comparative Comparative Example 20 Example 21 Description CVX UCBO 4R CVX UCBO 7R CVX Sample ID WOW8047 WOW8062 Hydroisomerization 600-750*F 600-750*F Temp, *F Hydroisomerization Pt/SSZ-32 Pt/SSZ-32 Dewaxing Catalyst Viscosity at 100*C, cSt 4.18 6.97 Viscosity Index 130 137 Aromatics, wt% 0.022 0.035 FIMS, Wt% of Molecules Paraffins 24.6 24.8 Monocycloparaffins 43.6 51.2 Multicycloparaffins 31.8 24.0 Total 100.0 100.0 API Gravity 39.1 37.0 Pour Point, C -18 -18 Cloud Point, 0C -14 5 Ratio of 1.4 2.1 Mono/Multicycloparaffins Aniline Point, D 611, *F 242.1 260.2 15 These two comparative examples demonstrate how lubricating base oils made with conventional waxy petroleum feeds, where the feeds contain high levels of sulfur and nitrogen, have high weight percents of all molecules with - 55 - 2999440-1 - 56 at least one cycloparaffin function. They also have low weight percents of all molecules with at least one aromatic function. However, they both have less desired very low ratios of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins, much below the desired ratio of greater than 15 of the lubricating base oils 5 of this invention. As a result, although they have aniline points similar to the lubricating base oils of this invention, they have lower viscosity indexes, below the desired level defined by the equation: VI = 28 x Ln (Kinematic Viscosity at 100*C) + 95. The reference in this specification to any prior publication (or information derived from it), or 10 to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. 15 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims (10)

1. 2999440-1 - 57 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A lubricating base oil made from Fischer-Tropsch wax, comprising: a. a weight percent of all molecules with at least one aromatic function less than 5 0.30; b. a weight percent of all molecules with at least one cycloparaffin function greater than 10; and c. a ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater than 15. 10
2. 2. The lubricating base oil of claim 1, further comprising a ratio of pour point in degrees Celsius to kinematic viscosity at 100'C in cSt greater than the Base Oil Pour Factor as calculated by the following equation: Base Oil Pour Factor = 7.35 x Ln(Kinematic Viscosity at I 00*C)- 18. 15
3. 3. The lubricating base oil of claim 1, wherein said weight percent of all molecules with at least one cycloparaffin function is greater than 15.
4. 4. The lubricating base oil of claim 3, wherein said weight percent of all molecules with 20 at least one cycloparaffin function is greater than 20.
5. 5. The lubricating base oil of claim 1, wherein said ratio is greater than 50.
6. 6. The lubricating base oil of claim 1, further comprising a viscosity index greater than 28 25 x Ln(Kinematic Viscosity at 100*C) +95.
7. 7. The lubricating base oil of claim 6, wherein said viscosity index is greater than 28 x Ln(Kinematic Viscosity at 100*C) +110. 30
8. 8. The lubricating base oil of claim 1, further comprising an aniline point less than or equal to an amount calculated by the following equation: Aniline Point, 'F = 36 x Ln(Kinematic Viscosity at 100*C) +200. 2999440-1 -58
9. 9. The lubricating base oil of claim 1, further comprising a Noack Volatility less than an amount calculated from the equation: Noack Volatility, Wt% = 1000 x (Kinematic Viscosity at I 00*C)~ . 5 10. The lubricating base oil of claim 1, wherein the kinematic viscosity at 100*C is between about 2 cSt and about 20 cSt. 11. The lubricating base oil of claim 1, further comprising an additional base oil selected 10 from the group consisting of conventional Group I base oils, conventional Group II base oils, conventional Group Ill base oils, other GTL base oils, isomerized petroleum wax, polyalphaolefins, polyinternalolefins, oligomerized olefins from Fischer-Tropsch derived feed, diesters, polyol esters, phosphate esters, alkylated aromatics, alkylated cycloparaffins, and mixtures thereof. 15 12. The lubricating base oil of claim 1, further comprising a CCS Viscosity at -35*C less than an amount calculated from the equation: CCS VIS (-35*C), cP = 38 x (Kinematic Viscosity at I 00,C) 3 . 20 13. The lubricating base oil of claim 12, wherein said CCS Viscosity at -35*C is less than the amount calculated from the equation: CCS VIS (-35*C), cP = 38 x (Kinematic Viscosity at 100*C) 2 8 . 14. A process for manufacturing a lubricating base oil, comprising the steps of: 25 a. performing a Fischer-Tropsch synthesis on syngas to provide a product stream; b. isolating from said product stream a substantially paraffinic wax feed having less than about 30 ppm total combined nitrogen and sulfur, and less than about I weight percent oxygen; c. dewaxing said substantially paraffinic wax feed by hydroisomerization 30 dewaxing using a shape selective intermediate pore size molecular sieve comprising a noble metal hydrogenation component, wherein the hydroisomerization temperature is between about 600*F (315*C) and about 750'F (399'C), whereby an isomerized oil is produced; and 2999440-1 -59 d. hydrofinishing said isomerized oil, whereby a lubricating base oil is produced having: i. a weight percent of all molecules with at least one aromatic function less than 0.30; 5 ii. a weight percent of all molecules with at least one cycloparaffin function greater than 10; and iii. a ratio of weight percent of molecules containing monocycloparaffins to weight percent of molecules containing multicycloparaffins greater than 15.
10. 10 15. The process of claim 14, wherein said substantially paraffinic wax feed has a weight ratio of molecules having at least 60 or more carbon atoms and molecules having at least 30 carbon atoms less than 0.10, and a T90 boiling point between 660"F (349'C) and 1200"F (649-C). 15 16. The process of claim 15, wherein the T90 boiling point is between 900F (482 *C) and 1200-F (649-C). 17. The process of claim 14, wherein said substantially paraffinic wax feed has a weight percent oxygen between 0.01 and 0.90 weight percent. 20 18. The process of claim 14, wherein said substantially paraffinic wax feed has a difference between the T90 and TIO boiling points greater than 160*C. 19. The process of claim 14, wherein said shape selective intermediate pore size molecular 25 sieve is selected from the group consisting of SAPO-l 1, SAPO-31, SAPO-41, SM-3, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57, SSZ-32, offretite, ferrierite, and combinations thereof. 20. The process of claim 14, wherein said noble metal hydrogenation component is platinum, palladium, or mixtures thereof. 30 21. The process of claim 14, wherein conversion of the compounds boiling above about 700 'F (370'C) in the wax feed to compounds boiling below about 700 'F (370'C) during the 2999440-1 - 60 hydroisomerization dewaxing is maintained between about 15 wt % and 45 wt%. 22. The process of claim 14, whereby the lubricating base oil has a ratio of monocycloparaffins to multicycloparaffins greater than 50. 5 23. The process of claim 14, whereby the lubricating base oil has a ratio of pour point to kinematic viscosity at 100*C greater than the Base Oil Pour Factor as calculated by the following equation: Base Oil Pour Factor = 7.35 x Ln(Kinematic Viscosity of said desired fraction at 10 100 C)-18. 24. The process of claim 14, further comprising blending the lubricating base oil with an additional base oil selected from the group consisting of conventional Group I Base Oils, conventional Group 11 base oils, conventional Group III base oils, other GTL base oils, 15 isomerized petroleum wax, polyalphaolefins, polyinternalolefins, oligomerized olefins from Fischer-Tropsch derived feed, diesters, polyol esters, phosphate esters, alkylated aromatics, alkylated cycloparaffins, and mixtures thereof. 25. A lubricating base oil manufacturing plant, comprising: 20 a. a means to produce a substantially paraffinic wax feed having i. less than about 30 ppm total combined nitrogen and sulfur, ii. less than about I weight percent oxygen, iii. greater than about 75 mass percent normal paraffin, iv. less than 10 weight percent oil, 25 v. a weight ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms less than 0.18, and vi. a T90 boiling point between 660*F and 1200F; b. a means for hydroisomerization dewaxing said substantially paraffinic wax feed using a shape selective intermediate pore size molecular sieve comprising a noble metal 30 hydrogenation component, wherein the hydroisomerization temperature is between about 600*F (315*C) and about 750'F (399*C), to produce an isomerized oil, and c. a means for hydrofinishing the isomerized oil to produce lubricating base oils 2999440-1 -61 having: i. a weight percent aromatics less than 0.30; ii. a weight percent total cycloparaffins greater than 10; and iii. a ratio of weight percent molecules containing monocycloparaffins to 5 weight percent molecules containing multicycloparaffins greater than 15. 26. A lubricating base oil made from a Fischer-Tropsch wax, a process for manufacturing a lubricating base oil, or a lubricating base oil manufacturing plant, substantially as hereinbefore described with reference to the accompanying drawings.