Catalyst and process for polymerizing ethylene

Claim 1

IN A PROCESS FOR THE PRODUCTION OF A NORMALLY SOLID POLYMERIC HYDROCARBON MATERIAL, THE STEPS WHICH COMPRISES CONTACTING A NORMALLY GASEOUS OLEFIN CONTAINING FROM 2 TO 8 CARBON ATOMS WITH A CHROMIUM OXIDE-CONTAINING CATALYST IN WHICH AT LEAST A PORTION OF THE CHROMIUM IS IN THE HEXAVALENT STATE PREPARED BY CONTACTING A SUPPORT WITH A SOLUTION OF CHROMIUM COMPOUND CONVERTIBLE TO OXIDE UPON HEATING SO AS TO DEPOSIT AN AMOUNT OF CHROMIUM ON SAID SUPPORT IN THE RANGE OF 0.1 TO 10 WEIGHT PERCENT OF THE RESULTING COMPOSITE, DRYING THE SAME AND HEATING SAID COMPOSITE AT A FIRST TEMPERTURE IN THE RANGE OF ABOUT 1500* TO 2000*F. AND A SECOND TEMPERATURE RANGE OF 800* TO 1500*F. FOR A PERIOD OF 2 TO 20 HOURS, SAID HEATING BEING CARRIED OUT AT SUCH TEMPERATURES TO PROVIDE A TEMPERATURE DIFFERENTIAL IN THE RANGE OF 300* TO 1200*F. AND SEPARATING A POLYMERIC HYDROCARBON MATERIAL THEREFROM.