Abstract: BF.sub.3 is vaporized from specified crude polyolefin reaction product mixture in a vaporization zone at a temperature insufficient to decompose BF.sub.3 or any BF.sub.3 promoter complex in the mixture, and the vaporized BF.sub.3 may be recovered directly. Further, a process for the oligomerization of a liquid olefin composition and recovery of BF.sub.3 is described in which inert volatile material present in a liquid olefin composition is removed from the composition by vaporization, forming a degassed liquid olefin composition free of inert volatile material. The degassed liquid olefin composition is then contacted in a reaction zone with BF.sub.3 under conditions to oligomerize the olefin, forming crude polyolefin oligomerization reaction product mixture containing dissolved BF.sub.3, which may be treated as described.

Abstract: A process for the recovery of BF.sub.3 from crude oligomerization reaction product mixture containing dissolved BF.sub.3 is described, the process being characterized by vaporization of BF.sub.3 from the crude oligomerization reaction product mixture in a vaporization zone at a temperature insufficient to decompose BF.sub.3 or any BF.sub.3 promoter-complex in the mixture. BF.sub.3 from the vaporization zone is then contacted with a liquid olefin composition under conditions to absorb BF.sub.3, in an absorption zone, forming a mixture comprising liquid olefin composition and BF.sub.3. The liquid olefin composition may be utilized directly for oligomerization of the liquid olefin therein.