METHOD FOR PREPARING POLY-ALPHA-OLEFINS Russian patent published in 2003 - IPC

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention proposes method for preparing poly-alpha-olefins. Method is carried out in two successively arranged reactor of flow-type filled with granulated aluminum oxide as a solid sorbent subjected for thermovacuum treatment preliminary. Alpha-olefins are passed through the first reactor at elevated temperature and pressure and prepared oligomerizate is cooled and BF₃ is desorbed from them by passing through the second reactor in the amount 100 volumes of oligomerizate per 1 volume of sorbent, not less. Then process is carried out in reverse direction, i. e: alpha-olefins are passed through the second reactor and obtained oligomerizate is passed through the first one with the following alternated feeding into the first or the second reactor under above indicated conditions and after desorption of BF₃ the end product is isolated from oligomerizate by rectification. Thermal treatment of granulated aluminum oxide is carried out at temperature 150-250 C under vacuum and then cooled up to temperature 20-60 C and treated with gaseous BF₃ under excessive pressure 0.1-1.2 MPa. Reaction of oligomerization is carried out at temperature 40-160 C under pressure 0.5-0.7 MPa using C₈-C₁₄-alpha-olefins. Oligomerizate is cooled at reactor outlet up to temperature 30-50 C followed by isolation of poly-alphaolefins with viscosity value 3.5-4.2 mm²/s/s at 100 C as the end product. The proposed method ensures preparing poly-alpha-olefins with required viscosity value designated for using as basic components of lubricating oils and provides using excessive amount of unreacted BF₃ completely without any loss and to exclude using co-promoters, in part, oxygen as in the known method. EFFECT: improved preparing method. 4 cl, 1 ex