Abstract:
Synthetic base oils for functional fluids and greases are provided comprising a mixture of monoalkylated naphthalenes and polyalkylated naphthalenes, said naphthalenes represented by the formula: ##STR1## wherein the R&#39; groups are independently selected from H and methyl, the monoalkylated naphthalenes have three R groups which are H and one R group which is a 12-26 carbon alkyl, the polyalkylated naphthalenes have from two to four R groups which are 12-26 carbon alkyl and any remainder R groups H, and the weight ratio of monoalkylated naphthalenes to polyalkylated naphthalenes is from 5:95 to 70:30 when the average alkyl group is C 12  -C 16  and from 5:95 to 99:1 when the average alkyl group is C 17  -C 26 . In the preferred mixture, the polyalkylated naphthalenes have a numerical ratio of α/β substitution of from 50/50 to 10/90 when the R&#39; groups are both H.

Description:
BACKGROUND OF THE INVENTION 
     There is a continuous need for synthetic oils such as lubricants and base stocks for greases of moderate cost with a combination of low volatility at high temperatures (&gt;200° C.), high flash points (&gt;260° C./500° F.), high fire points (&gt;530° F.), excellent viscosity indices (≧100), good pour points (as low as -40° F.), good lubricity and good response to additives. 
     A group of synthetic oils have now been discovered that fulfills all or most of the above requirements. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Synthetic oils have been discovered comprising a mixture of monoalkylated naphthalenes and polyalkylated naphthalenes, said naphthalenes represented by the formula: ##STR2## wherein the R&#39; groups are independently selected from H and methyl, the monoalkylated naphthalenes have three R groups which are H and one R group which is a 12-26 carbon alkyl, the polyalkylated naphthalenes have from two to four R groups which are 12-26 carbon alkyl and any remainder R groups H, and the weight ratio of monoalkylated naphthalenes to polyalkylated naphthalenes is from 5:95 to 70:30 when the average alkyl group is C 12  -C 16  and from 5:95 to 99:1 when the average alkyl group is C 17  -C 26 . In the preferred mixture, the polyalkylated naphthalenes have a numerical ratio of α/β substitution of from 50/50 to 10/90 when the R&#39; groups are both H. 
     Thus, the mixture comprises naphthalenes, methyl naphthalenes and dimethyl naphthalenes and their mixtures alkylated with C 12  to C 26  alkyl groups. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In formulating the synthetic oils of the invention, the amount of monoalkylated naphthalene employed in the oil will depend upon the use contemplated for the oil, the particular olefins employed, whether a single olefin or a mixture of olefins is employed to make the polyalkylated naphthalene, and whether a single or mixture of monoalkylated naphthalenes is employed. 
     Generally, however, the ratio of monoalkylated naphthalene to polyalkylated naphthalene should be from 5:95 to 70:30 by weight, preferably from 5 to 30% monoalkylnaphthalene when the monoalkylated and the polyalkylated alkyl groups are C 12  to C 16  and 15 to 99% monoalkylnaphthalene when said alkyl groups are greater than C 16 . 
     The synthetic oils are manufactured by reacting naphthalene with an α-olefin (to include mixtures) in a molar ratio of from 1 naphthalene:0.8 olefin to 1 naphthalene:5 olefin at elevated temperatures between about 150° C. and about 260° C. for a time between about 0.25 hrs. and about 6 hrs. in the presence of a catalyst. The ratio of monoalkylated naphthalene to polyalkylated naphthalene can be varied by adjusting the mole ratio of reactants. For example, if it is desired to prepare mixtures high in monoalkylated naphthalene of 50% or more by weight then a mole ratio of naphthalene to olefin of about 1:1 is employed. If it is desired to prepare dialkylated naphthalenes, a mole ratio of naphthalene to olefin of about 1:2.2 is employed. For trialkylated naphthalenes, a mole ratio of naphthalene to olefin of about 1:4 is employed, and a ratio of 1:5 naphthalene to olefin is employed for tetraalkylated naphthalenes. An inert diluent, such as an aliphatic hydrocarbon, may be used. Suitable catalysts include the activated clay alumina silicates and high silica zeolites which are used in an amount from between about 10 wt.% and about 100 wt.% based on the naphthalene. The products are essentially free of unsaturated by-products which would increase their susceptibility to oxidation. The synthetic base oils can be used for making lubricants, hydraulic fluids, vacuum pump oils, heat transfer fluids, and other functional fluids and lithium, aluminum, bentonite and urea complex greases. 
    
    
     The invention will be illustrated in more detail in the following examples. All parts and percentages in said examples and elsewhere in the specification and claims are by weight unless otherwise specified. 
     EXAMPLE 1 
     A 1-l glass reactor was charged with 130.0 g. (1.02 m) of naphthalene, 564.0 g. (2.25 m) of Chevron Chemical Co. C 15-20  α-olefin, which consists of 1% C 14 , 17% C 15 , 18% C 16 , 17% C 17 , 17% C 18 , 15% C 19 , 12% C 20 , and 3% C 21  olefin, and 70.0 g. of Filtrol-13 acid activated silica alumina clay (low moisture catalyst). The charge was agitated and heated to 200° C., held at this temperature for six hours, then allowed to cool to room temperature (25° C.) and discharged. The resultant slurry was filtered and the filtrate was distilled to a pot temperature of 260° C. at 1 torr to provide 456.7 g. (65.8% yield on the organics charged; 79.5% yield corrected for losses, mostly holdup in the filter cake) of a residual product as a light amber oil. By IR/NMR ( 1  H and  13  C) analysis this residue consisted of 73% of polyalkyl(C 15  -C 20 ) substituted naphthalenes with about 80% beta substitution and 27% monoalkylated naphthalenes (determined by IR/NMR and GC analysis). 
     The product had a viscosity of 84 SUS at 210° F., flash point 520° F. (ASTM D92), viscosity index 110, and pour point -5° F. (ASTM D97). 
     EXAMPLE 2 
     A 2-l glass reactor was charged with 130.0 g (1.02 m) of naphthalene, 504.0 g. (2.25 m) of hexadecene-1 (Shell Chemical&#39;s Neodene-16), and 70.0 g. of Filtrol-13. The mixture was agitated and reacted at 200° C. for 6 hrs., then allowed to cool to room temperature (25° C.) and filtered. The filtrate was distilled to a pot temperature of 260° C. at 1 torr to provide 490.7 g (77.4% yield based on the organics charged; 86.8% yield corrected for losses) of a gold-colored oil. The product was identified by IR/NMR analysis as a naphthalene having an average of two C 16  -alkyl substituents with 34/66 ratio of α- to β substitution, and containing 24% of C 16  -monosubstituted naphthalene. No olefinic double bond was detectable in this oil. The oil had a flash point of 515° F.; a fire point of 575° F.; a pour point of - 30° F.; a viscosity of 545 SUS and 69.8 SUS at 100° F. and 210° F., respectively, and a viscosity index of 110. 
     To test for lubricity, the products of Examples 1 and 2 were compared with a commercial mineral oil and two synthetic ester oils in industrial lubricant evaluation tests according to ASTM D2596 and D2266. The results are shown in the following Table I. 
     
                                           TABLE I__________________________________________________________________________           Products of                  Sohio                      HUMKO                           SYNLUBE           Ex. 1              Ex. 2.                  600.sup.1                      3681.sup.2                           500.sup.3                                 TMPTH.sup.4__________________________________________________________________________Four-Ball EPLoad Wear Index, Kg              21.09                  19.96Weld, Kg           126.0                  80.0Four-Ball Wear     0.27                  0.30Scar, mm at 20 Kg1800 rpm, 130° F., 1 hr.Oxidation Stability Test (neat oil)% Evaporation at 400° F.after 24 hrs.   22.9              23.0                  34.3                      82.2 87.8  Solidafter 48 hrs.   29.8              29.3after 72 hrs.   32.6              31.6after 96 hrs.   Solid              35.4Hours to Solidification           96 103 48  24   24    24at 400° F.Viscosity, SUS100° F.     546 600      87210° F.     70  69  66   40% Sludge (Hexane)           -- 18  --  --   --    51.0Insolubles after #Hrs. at 400° F.Flash Point (COC), °F.           -- 515 515 --   490   460__________________________________________________________________________ .sup.1 product of Standard Oil Company of Ohio .sup.2 product of Humko Chemical Company .sup.3 product of Synlube International Co. .sup.4 trimethylolpropane trin-heptanoate, Product of Stauffer Chemical Co. From the results, it can be seen that the products of the invention compare favorably with or are better than the commercial products. 
    
     Other useful synthetic oils and their properties are shown in the attached Table II. The alkylated naphthalenes were prepared in a manner similar to Examples 1 and 2. 
     
                                           TABLE II__________________________________________________________________________                           Product              Reaction              %              Temp/        Number                                Ratio                                    Mono                                        Flash                                            PourCatalyst Reactant.sup.a              Time Ex.     Alkyl                                α-β                                    alky-                                        pt.,                                            pt.,                                               Viscosity, SUS(gm)     Quantities              °C.                 hr.                   No Olefin.sup.b                           Grps.                                Substit.                                    late                                        °F.                                            °F.                                               100° F.                                                   210°                                                       V.I.__________________________________________________________________________ALKYNAPHTHALENES-STRUCTURE VS. PROPERTIES70.0 Filtrol 13    1.0mN;4.0mC.sub.14              150                 5.5                    3 C.sub.14 S                           3.0  43:57                                    10  512 --  39 62  11357.0 Filtrol 13    0.5mN;2.5mC.sub.14              200                 4  4 C.sub.14 S                           3.6  36:64                                    12  525 -40                                               700 79  10965.0 Filtrol 13    2.0mN;2.0mC.sub.18              220                 1  5 C.sub.18 S                           1.5   5:95                                    50  508 +5 389 61  11460.0 Filtrol 13    0.42mN;2.25mC.sub.18              200                 4  6 C.sub.18 S                           2.8  20:80                                    --  535 -- 460 69  11870.0 Filtrol 13    1.0mN;2.25mC.sub.16              200                 6  7 C.sub.16 G                           2.0  34:66                                    24  515 -30                                               525 68  1103.56 lb. Filtrol 13    6.6 lb.N;25.6 lb.C.sub.16              175                 6  8 C.sub.16 S                           2.1  54:46                                    20  520 -5 571 72  111100 Filtrol 13    0.8mN;4.0C.sub.16              175                 5  9 C.sub.16 S                           3.0  39:61                                    16  535 -- 560 75  12070.0 Filtrol 13    1.0mN;3.5mC.sub.12-14              175                 6 10 C.sub.12-14 E                           3.0  --  --  520 -- 480 65  10678 Filtrol 13    0.9mN;2.1mC.sub.12-14              200                 4 11 C.sub.12-26 E                           2.4  33:67                                    --  560 +5 791 84  11770 Filtrol 13    1.0mN;2.5mC.sub.14-16              200                 4 12 C.sub.14-16 S                           2.3  --  17  545 -- 525 69  10956 Filtrol 13    2.0mN;4.4mC.sub.14-16              220                 1 13 C.sub.14-16 S                           --   --  17  520 -- 562 88  13670 Filtrol 13    1.0mN;2.5mC.sub.14-18              200                 4 14 C.sub.14-18 S                           2.4  24:76                                    --  545 -- 580 77  11252 Filtrol 13    1.0mN;2.2mC.sub.14-18              220                 3 15 C.sub.14-18 E                           2.0  12:88                                    24  520 -- 510 69  10556 Filtrol 13    2.0mN;4.5mC.sub.14-18              220                 1 16 C.sub.14-18 S                           --   --  17  545 -- 585 74  114280 Filtrol 13    3.5mN;7.9mC.sub.15-20              200                 4 17 C.sub.15-20 C                           2.0  37:63                                    26  533 -- 640 77  11045 Filtrol 13    0.5mN;1.6mC.sub.16-18              175                 6 18 C.sub.16-18 E                           2.2  50:50                                    26  530 -- 510 72  11475 Filtrol 13    1.0mN;3.0mC.sub.18-20              200                 4 19 C.sub.18-20 E                           2.0  40:60                                    22  540 -- 590 77  11778 Filtrol 13    1.0mN;2.2mC.sub.20-24              200                 4 20 C.sub.20-24 G                           2.1  37:63                                    --  550 -- 625 80  116COMPARISON OILS36 Filtrol 13    0.8mN;3.2mC.sub.8              200                 3 21 C.sub.8 F                           2.9  30:70                                    --  485 -- 200 74   69              220                 145 Filtrol 24    1.0mN;2.2mC.sub.10              200                 4 22 C.sub.10 G                           2.2  23:77                                    5.3 485 -- 550 60   7865 Filtrol 13    2.0mN;2.0mC.sub.16              220                 0.5                   23 C.sub.16 G                           1.1  12:88                                    100*                                        453 -- 140 45  136__________________________________________________________________________ .sup.a N = naphthalene; .sup.b S = Shell Oil Corp.; G = Gulf Oil Corp.; E = Ethyl Corp.; F = Fisher Scientific Corp.; and C = Chevron Corp. .sup.* = Distilled to obtain monoalkylate 
    
     In the following Table III base oils of the invention are compared with commercial oils. The base oils of Examples 24-34 were made in accordance with the general procedure of Examples 1 and 2. The resultant products had a weight ratio of monoalkylated naphthalene to polyalkylated naphthalene within the claimed range and the polyalkylated naphthalenes had a numerical ratio of α/β substitution within the preferred range. The olefins employed are listed by carbon number, or carbon number range for mixed olefins, in the table. 
     
                                           TABLE III__________________________________________________________________________COMPARATIVE EVALUATION OF ALKYLNAPHTHALENES OF THEINVENTION WITH COMMERCIAL OILS__________________________________________________________________________Product                        Monsanto OS-124                                     Stauffer TMPTHIdentification      Sohio 600 Mineral Oil                          Poly (phenyl ether)                                     Triol triester__________________________________________________________________________Flash pt., °F.               450        550        460Pour pt., °F.               -8         +40        -90Viscosity,SUS, 100° F.  1682       77.0Viscosity,SUS, 210° F.  70.2       37.5Viscosity Index                -70Evaporation loss, wt. %, 400° F., 24 hrs.               23.2       5.3        92.7Evaporation loss, wt. %, 400° F., 48 hrs.                          14.3Evaporation loss, wt. %, 400° F., 72 hrs.                          23.1Evaporation loss, wt. %, 400° F., 96 hrs.                          30.0Evaporation loss, wt. %, 400° F., 103 hrs.                          31.5Evaporation loss, wt. %, 400° F., 127 hrs.Hours to solidify   48         200+       24Sludge, wt. % at 103 hrs.      1.1Sludge, wt. % at 150 hrs.      10.4__________________________________________________________________________               NASA                 SynlubeProduct             Mil. Spec. 23699 Oil                             Humko 3681                                    500  501Identification      Fully formulated polyolester                             Ester  Di-ester                                         Di-ester__________________________________________________________________________Flash pt., °F.             490    490  490Pour pt., °F.               -90                  -36  -70Viscosity,SUS, 100° F.               78.2                 86.5 80Viscosity,SUS, 210° F.               37.8          66     39.5 38Viscosity Index     125                  177  154Evaporation loss, wt. %, 400° F., 24 hrs.               100           82.2   87.8 91.0Evaporation loss, wt. %, 400° F., 48 hrs.Evaporation loss, wt. %, 400° F., 72 hrs.Evaporation loss, wt. %, 400° F., 96 hrs.Evaporation loss, wt. %, 400° F., 103 hrs.Evaporation loss, wt. %, 400° F., 127 hrs.Hours to solidify   24     24     24     24   72Sludge, wt. % at 103 hrs.  51(24 hrs.)Sludge, wt. % at 150 hrs.__________________________________________________________________________Example             24    25   26   27   28   29Identification      2.8C.sub.12-                     3.6C.sub.14-                          3.0C.sub.14-                               2.2C.sub.16-                                    2.0C.sub.16-                                         3.0C.sub.16-__________________________________________________________________________Flash Pt., °F.               535   525  525  525  515  535Pour pt., °F.               -40   -40  -40  -5   -30  0Viscosity,SUS, 100° F.               849   699  668  571  546  560Viscosity,SUS, 210° F.               84.0  79.3 77.7 71.8 69.8 74.6Viscosity Index     102   110  95   111  110  119Evaporation loss, wt. %, 400° F., 24 hrs.               13.8  16.2 16.5 18.3 23.0 14.1Evaporation loss, wt. %, 400° F., 48 hrs.               29.8  21.4 26.5 25.2 29.3 19.5Evaporation loss, wt. %, 400° F., 72 hrs.               40.3  26.8      29.9 31.6 24.9Evaporation loss, wt. %, 400° F., 96 hrs.               45.9  31.0      33.8 35.4 28.6Evaporation loss, wt. %, 400° F., 103 hrs.                     32.0      34.5      28.7Evaporation loss, wt. %, 400° F., 127 hrs.                                         32.1Hours to Solidify   96         72   103  103Sludge, wt. % at 103 hrs. 4.2       4.0       41.1**Sludge, wt. % at 150 hrs. 24.5      2.7*__________________________________________________________________________Example             30     31    32    33    34Identification      2.0C.sub.18-                      2.4C.sub.12-26                            2.1C.sub.14-26                                  C.sub.14-28                                        C.sub.15-20__________________________________________________________________________Flash Pt., °F.               525    560   570   520Pour pt., °F.               0      +5    +10   wax   -5Viscosity,SUS, 100° F.               603    791   750   --    700Viscosity,SUS, 210° F.               75.3   84.3  82.9  89.1  83.5Viscosity Index     114    117   111   --    110Evaporation loss, wt. %, 400° F., 24 hrs.               17.1   9.9   10.4  11.2  27.7Evaporation loss, wt. %, 400° F., 48 hrs.               24.2   15.0  15.8  14.8  33.1Evaporation loss, wt. %, 400° F., 72 hrs.               29.2   20.8  20.3  18.5  46.2Evaporation loss, wt. %, 400° F., 96 hrs.               32.5   24.9  24.1  21.4  50.2Evaporation loss, wt. %, 400° F., 103 hrs.               26.0   25.4  21.7Evaporation loss, wt. %, 400° F., 127 hrs.               30.2   29.2Hours to Solidify   103    127   127   103   96Sludge, wt. % at 103 hrs.               23.2** 55.6**                            2.4   26.5***Sludge, wt. % at 150 hrs.__________________________________________________________________________Example             35     36    37    38    39Introduction        2.0C.sub.15-20                      1.8C.sub.15-20                            2.0C.sub.15-20                                  1.7C.sub.18-24                                        2C.sub.24-28__________________________________________________________________________Flash pt., °F.               505    515   540   550   545Pour pt., °F.               0            +25   +10   waxViscosity,SUS, 100° F.,               698    588   644   692   --Viscosity Index     79.0   71.5  79.0  80.2  91.0Evaporation loss, wt. %, 400° F., 24 hrs.               109    107   116   113   --Evaporation loss, wt. %, 400° F., 48 hrs.               22.9   29.9  15.5  15.3  9.0Evaporation loss, wt. %, 400° F., 72 hrs.               29.8   36.9  22.9  23.9  13.0Evaporation loss, wt. %, 400° F., 96 hrs.               32.6   43.8  26.0  30.9  17.6Evaporation loss, wt. %, 400° F., 103 hrs.                      48.3  29.2  32.9  21.0Evaporation loss, wt. %, 400° F., 127 hrs.                                  33.6  21.6Hours to Solidify   96     96    103   103   103Sludge, wt. % at 103 hrs.Sludge, wt. % t 150 hrs.         25.0***                                  4.5   15.2__________________________________________________________________________ *Added 1 wt. % phosphite of 4, 6di-t-butylresorcinol **% Sludge at 127 hrs. ***% Sludge at 96 hrs. 
    
     The following grease formulations (components in parts) are illustrative of the use of the synthetic oils of the invention. 
     
         __________________________________________________________________________GREASES                            Commercial Bentone        40  41  42  43  44  Grease with Mineral Oil__________________________________________________________________________Bentone Clay.sup.1        6.4 8.8         6.4 6.4Polyalkylated        92.2            88.8                84.1                    83.2Naphthalene.sup.2Oxidation Inhibitor.sup.3            1.0 1.0Stearic Acid         5.2 6.7Azelaic Acid         5.1Benzoic Acid             2.9Mineral Oil                      92.2Anti Wear Vanlube 71.sup.4                    2.0Acetone &amp; H.sub.2 O        1.4 1.4         1.4 1.4Aluminum Hydrate         5.2Alpha-olefine polymer.sup.5  92.2Lithium Hydroxide    4.6ASTM D1263-61 modified        308 493 409 576 168 103at 305° F. in hours-Bearing Life__________________________________________________________________________ .sup.1 Product of National Lead Co. .sup.2 2C.sub.16 alkyl groups &amp; 20% C.sub.16 monoalkyl; pour point -5° F., Flash pt. 525° F.;α/β substitution 54/46 .sup.3 Tris(4,6di-t-butyl-3-hydroxyphenyl) phosphite .sup.4 Product of R. T. Vanderbilt Co. .sup.5 A 6 cSt synfluid of Gulf Chemical Co. 
    
     From the above, it can be seen that the compositions of the invention have a number of useful properties. Obvious modifications may be apparent to one or ordinary skill, however, and thus the invention is intended to be limited only by the appended claims.