| abstract |
Process for polymerizing olefinic hydrocarbons at a temperature from 0° to 90° C., preferably from 20° to 80° C. in the presence of a catalyst containing aluminum oxide and, per part by weight thereof, boron oxide in a proportion of 0.01 to 1, preferably 0.07 to 0.15 part by weight and halogen in a proportion of 0.5 to 20%, preferably 4 to 12%, said catalyst resulting from the reaction of an aluminum compound of formula AlX y R.sub.(3-y) where X is halogen, R is a hydrocarbon radical and y is selected from 1, 3/2, 2 and 3, with a carrier containing aluminum oxide and boron oxide in a proportion to aluminum oxide from 1 to 100%. |