This permitted {HEAD ~ compositions} to be processed without {TAIL ~ carbon additions}, as shown by the density data in FIG 2 
to be processed without
This permitted { HEAD ~ compositions } to be processed without { TAIL ~ carbon additions } , as shown by the density data in FIG 2
OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH