Ultra high viscosity synthetic base stocks and processes for preparing same

Abstract

Provided is a polyalphaolefin (PAO) fluid including a polymer of one or more C 8 to C 12 alphaolefin monomers. The PAO has a viscosity (Kv 100 ) from 300 to 900 cSt at 100° C.; a viscosity index (VI) greater than 250; a pour point (PP) less than −25° C.; a molecular weight distribution (Mw/Mn) less than 2.0 as synthesized; a residual unsaturation (Bromine Number) less than 2.0; and a glass transition temperature T g less than −60° C. The PAO also has no crystallization peak as measured by differential scanning calorimetry and high thermal stability. A process to make and use the PAOs, including those having any combination of characteristics above is also provided. The PAOs are useful as synthetic base stocks and co-base stocks in lubricating oils, e.g., industrial lubes.

What is claimed is: 
     
         1 . A polyalphaolefin (PAO) fluid comprising a polymer of one or more C 8  to C 12  alphaolefin monomers, said PAO having:
 a) a viscosity (Kv 100 ) from 300 to 900 cSt at 100° C.;   b) a viscosity index (VI) greater than 250;   c) a pour point (PP) less than −25° C.;   d) a molecular weight distribution (Mw/Mn) less than 2.0 as synthesized;   e) a residual unsaturation (Bromine Number) less than 2.0 as synthesized; and   f) a glass transition temperature T g  less than −60° C.   
     
     
         2 . The polyalphaolefin (PAO) fluid of  claim 1 , wherein said PAO further has:
 g) no crystallization peak as measured by differential scanning calorimetry.   
     
     
         3 . The polyalphaolefin (PAO) fluid of  claim 1  wherein the PAO has a kinematic viscosity at 100° C. of 400 to 800 cSt. 
     
     
         4 . The polyalphaolefin (PAO) fluid of  claim 1  wherein the PAO has an as-synthesized Mw/Mn of 1.9 or less. 
     
     
         5 . The polyalphaolefin (PAO) fluid of  claim 1  wherein the PAO has an as-synthesized Bromine number of less than 1.9. 
     
     
         6 . The polyalphaolefin (PAO) fluid of  claim 1  wherein the monomers are alphaolefins selected from the group consisting of octene, nonene, decene, undecene and dodecene. 
     
     
         7 . A process for producing a polyalphaolefin (PAO) comprising:
 contacting in a reactor a feed stream comprising at least one alphaolefin monomer having 8 to 12 carbon atoms with a catalyst system comprising a precatalyst compound and a non-coordinating anion activator, and optionally an alkyl-aluminum compound, under polymerization conditions, optionally in the presence of hydrogen, and the alphaolefin monomer having 8 to 12 carbon atoms is present at 10 volume % or more, based upon the total volume of the catalyst, monomers, and any diluents or solvents present, in the reactor; and   obtaining the PAO;   wherein the precatalyst compound is represented by the formula   
       
         
           
           
               
               
           
         
       
       wherein:
 M is a group 4 metal; 
 L 1  is a unsubstituted fluorenyl, unsubstituted heterocyclopentapentalenyl, unsubstituted heterofluorenyl, substituted fluorenyl, substituted heterocyclopentapentalenyl, or substituted heterofluorenyl ligand with pseudo symmetric substituents, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl, and optionally two or more adjacent substituents may join to form a substituted or unsubstituted, saturated, partially unsaturated or aromatic, cyclic or polycyclic substituent; 
 L 2  is a cyclopentadienyl ring or a substituted cyclopentadienyl ring with pseudo symmetric substituents in the 2 and 5 positions of the ring, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl; 
 G is a bridging group; and 
 each X is independently halogen, alkoxide, aryloxide, amide, phosphide, hydride radicals, hydrocarbyl radicals, substituted hydrocarbyl radicals, halocarbyl radicals, substituted halocarbyl radicals, silylcarbyl radicals, substituted silylcarbyl radicals, germylcarbyl radicals, or substituted germylcarbyl radicals; or both X are joined and bound to the metal atom to form a metallacycle ring containing from 3 to 20 carbon atoms; or both together can be an olefin, diolefin or aryne ligand; or both X can also be joined to form a anionic chelating ligand. 
 
     
     
         8 . The process of  claim 7  wherein the precatalyst compound is represented by the formula 
       
         
           
           
               
               
           
         
       
       wherein each R a  and R b  are selected from hydrogen, halogen, hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl, germylcarbyl or polar radicals, and optionally two or more adjacent substituents may join to form a substituted or unsubstituted, saturated, partially unsaturated or aromatic, cyclic or polycyclic substituent, with the proviso that each R a  is the same and each R b  is the same and allow the compound to be C s -symmetric or pseudo C s -symmetric; each R c  is a pseudo symmetric substituent with respect to the other and is selected from hydrogen or a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl radicals; each R d  is a pseudo symmetric substituent with respect to the other and is selected from hydrogen or a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl radicals. 
     
     
         9 . The process of  claim 7  wherein the PAO has the following characteristics:
 a) a viscosity (Kv 100 ) from 300 to 900 cSt at 100° C.; 
 b) a viscosity index (VI) greater than 250; 
 c) a pour points (PP) less than −25° C.; 
 d) a molecular weight distribution (Mw/Mn) less than 2.0 as synthesized; 
 e) a residual unsaturation (Bromine Number) less than 2.0 as-synthesized; and 
 f) a glass transition temperature T g  less than −60° C. 
 
     
     
         10 . The process of  claim 9  wherein said PAO further has:
 g) no crystallization peak as measured by differential scanning calorimetry. 
 
     
     
         11 . The process of  claim 7  further comprising 1) optionally treating the PAO to reduce heteroatom containing compounds to less than 600 ppm; and/or 2) optionally separating the PAO from solvents or diluents; and/or 3) contacting the PAO with hydrogen, and a hydrogenation catalyst; and/or 4) obtaining a PAO having a Bromine Number less than 1.8. 
     
     
         12 . The process of  claim 7  wherein the activator comprises one or more of N,N-dimethylanilinium tetra(pentafluorophenyl)borate, N,N-dialkylphenylanilinium tetra(pentafluorophenyl)borate where the alkyl is a C 1  to C 18  alkyl group, trityl tetra(pentafluorophenyl)borate, tris(pentafluorophenyl)boron, tri-alkylammonium tetra(pentafluorophenyl)borate where the alkyl is a C 1  to C 18  alkyl group, tetra-alkylammonium tetra(pentafluorophenyl)borate where the alkyl is a C 1  to C 18  alkyl group. 
     
     
         13 . The process of  claim 7  wherein an alkylaluminum compound is present and the alkylaluminum compound is represented by the formula: R 3 Al, where each R is, independently, selected from the group consisting of methyl, ethyl, n-propyl, iso-propyl, iso-butyl, n-butyl, t-butyl, n-pentyl, iso-pentyl, neopentyl, n-hexyl, iso-hexyl, n-heptyl, iso-heptyl, n-octyl, iso-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, and their iso-analogs. 
     
     
         14 . The process of  claim 7  wherein the pressure in the reactor is from 0.1 to 100 atmospheres. 
     
     
         15 . The process of  claim 7  wherein the metallocene comprises diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride. 
     
     
         16 . The process of  claim 7  wherein the monomers are contacted with the metallocene compound and the activator in a reactor and the reactor is a continuous stirred tank reactor, a continuous tabular reactor, or a batch reactor. 
     
     
         17 . The process of  claim 7  wherein the monomers are contacted with the metallocene compound and the activator in a solution phase or a slurry phase. 
     
     
         18 . The process of  claim 7  wherein the productivity is greater than 50 kg/g of metallocene compound or is greater than 10 kg/g of activator. 
     
     
         19 . The process of  claim 7  wherein the catalyst system comprises a chain transfer agent. 
     
     
         20 . A lubricant comprising (i) a base stock comprising the PAO of  claim 1 , or (ii) a conventional base stock and a co-base stock, wherein the co-base stock comprises the PAO of  claim 1 .