The CO and H2 are reacted under {HEAD ~ high pressures} to produce {TAIL ~ methanol} 
to produce
The CO and H2 are reacted under { HEAD ~ high pressures } to produce { TAIL ~ methanol }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL