| 摘要 |
The invention is directed to method of making a thermally and oxidatively stable lubricating oil having a high viscosity index and a low pour point by the thermal polymerization of 1-olefins containing 8 to 10 carbon atoms, the preferred 1-olefins are 1-decanes. The polymerization is conducted at temperatures ranging from 280 DEG C. to 350 DEG C. and low pressures, of less than about 280 psig, in a reactor which is free of catalytic material. Thereafter, the polyalphaolefin is hydrotreated over a nickel catalyst, preferably nickel on Kieselguhr. In an improved process the polyalphaolefin is separated from a low molecular weight product by distillation. The low molecular product contains unreacted 1-olefins which are recycled to the thermal polymerization zone to produce more of the lubricant base stock. The remaining lower molecular weight olefinic materials which include mixed olefins, paraffins, cracked olefins and olefin dimers are routed to a polymerization zone to make a second lubricant base stock.
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