The temperature and pressure are not critical, but {HEAD ~ the reaction} is preferably carried out at reflux temperature and {TAIL ~ atmospheric pressure} 
carried out at
The temperature and pressure are not critical , but { HEAD ~ the reaction } is preferably carried out at reflux temperature and { TAIL ~ atmospheric pressure }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL