{TAIL ~ The reactants} can be heated for {HEAD ~ between about 6 hours} and about 8 hours 
{ TAIL ~ The reactants } can be heated for { HEAD ~ between about 6 hours } and about 8 hours
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH