Patent ID: 8536391

Claim:
A method for producing a polyalphaolefin, the method comprising: a) contacting an alpha olefin monomer and a catalyst system, wherein the alpha olefin monomer comprises at least 80 weight percent of a C 8 normal alpha olefin, and wherein the catalyst system comprises: 1) a metallocene, 2) a first activator comprising a solid oxide chemically-treated with an electron withdrawing anion, 3) a second activator comprising an organoaluminum compound having the formula: Al(X 10 ) n (X 11 ) 3-n wherein X 10 is independently a C 1 to C 20 hydrocarbyl, X 11 is independently a halide, a hydride, or a C 1 to C 20 hydrocarboxide, and n is a number from 1 to 3; b) forming an oligomer product comprising dimers, trimers, and higher oligomers under oligomerization conditions; c) separating an oligomerization reactor effluent comprising the oligomer product to provide a heavy oligomer product, wherein at least a portion of the alpha olefin monomer, dimers, or trimers are removed from the oligomerization reactor effluent to form the heavy oligomer product; and d) hydrogenating the heavy oligomer product to provide the polyalphaolefin; wherein: the polyalphaolefin comprises i) less than 0.5 weight % hydrogenated alpha olefin monomer, ii) less than 1 weight % hydrogenated dimers, and iii) at least 88 weight % hydrogenated higher oligomers; and the polyalphaolefin has i) a 100° C. kinematic viscosity of at least 15 cSt, ii) a viscosity index greater than 155, iii) a pour point less than −35° C., and iv) no discernable crystallization as determined by differential scanning calorimetry using ASTM D 3418.