A novel
liquid phase polymerization process for preparing a
polyolefin product having preselected properties is disclosed. The process includes the steps of providing a liquid feedstock which contains an olefinic component and a catalyst composition consisting of a stable complex of BF3 and a complexing agent therefor. The feedstock may comprise any one or more of a number of olefins including branched olefins such as
isobutylene, C3 to C15 linear alpha olefins and C4 to C15 reactive non-alpha olefins. The feedstock and the catalyst composition are introduced into a residual reaction mixture recirculating in a loop reactor
reaction zone provided in the tube side of a
shell and tube heat exchanger at a recirculation rate sufficient to cause intimate intermixing of the residual reaction mixture, the added feedstock and the added catalyst composition. The heat of the
polymerization reaction is removed from the recirculating intimately intermixed reaction admixture at a rate calculated to provide a substantially constant
reaction temperature therein while the same is recirculating in said
reaction zone. The conditions in the reactor are appropriate for causing olefinic components introduced in said feedstock to undergo
polymerization to form the desired
polyolefin product in the presence of the catalyst composition. A product
stream containing the desired
polyolefin product is withdrawn from the
reaction zone. The introduction of the feedstock into the reaction zone and the withdrawal of the product
stream from the reaction zone are controlled such that the
residence time of the olefinic components undergoing polymerization in the reaction zone is appropriate for production of the desired polyolefin product.