{HEAD ~ The process} 5 wherein {TAIL ~ unreacted olefin} is removed from the titanium halide before the electron donor is added 
wherein
{ HEAD ~ The process } 5 wherein { TAIL ~ unreacted olefin } is removed from the titanium halide before the electron donor is added
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH