The CO and H2 components of the first stream are reacted under high pressures and, optionally, in {HEAD ~ the presence} of a catalyst, such as a copper and zinc containing catalyst, to form {TAIL ~ methanol} and higher alcohols 
to form
The CO and H2 components of the first stream are reacted under high pressures and , optionally , in { HEAD ~ the presence } of a catalyst , such as a copper and zinc containing catalyst , to form { TAIL ~ methanol } and higher alcohols
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH