The mixture is stirred for from 6 to 24 hours at {HEAD ~ room temperature} to complete {TAIL ~ the reaction} 
to complete
The mixture is stirred for from 6 to 24 hours at { HEAD ~ room temperature } to complete { TAIL ~ the reaction }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL