Patent ID: 8440872

Claim:
A process for preparing poly alpha olefins from a Fisher-Tropsch liquid, the process comprising the steps of: (a) contacting an unpurified C 5 -C 18 fraction of an alpha-olefinic hydrocarbon mixture produced from thermal cracking a C 20 -C 25 Fisher-Tropsch product with an oligomerization catalyst under conditions to produce an oligomerized product, wherein said conditions include a temperature between 0° C. and 250° C. for a time sufficient to produce the oligomerized product; wherein the oligomerization catalyst comprises promoted aluminum trichloride, wherein the oligomerization step olefin conversion is at least 80% and the selectivity to C 30 + lube range material is at least 93.7%, and (b) fractionating the oligomerized product to obtain a fractionated product having an average carbon number greater than 24, and wherein the C 20 -C 25 Fisher-Tropsch product is produced from the following process steps: (c) heating a Fisher-Tropsch liquid and flashing off or distilling off light material at a pressure greater than one atmosphere and recovering a bottoms stream; (d) vacuum fractionating the bottoms stream to form a C 19− overhead stream, a C 20 -C 25 Fisher-Tropsch product; and a C 26+ bottoms stream, and with the proviso that the C 20 -C 25 Fisher-Tropsch product is produced without a hydrotreating step to remove oxygenates either before or after the heating step of (c).