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