{TAIL ~ A further order} of addition is such that the electron donor is initially contacted with the transition metal component for {HEAD ~ up to 40 seconds} 
{ TAIL ~ A further order } of addition is such that the electron donor is initially contacted with the transition metal component for { HEAD ~ up to 40 seconds }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD