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