{HEAD ~ The process} 16 where {TAIL ~ the reaction} is conducted at a temperature between about 220° and about 300° C 
{ HEAD ~ The process } 16 where { TAIL ~ the reaction } is conducted at a temperature between about 220 ° and about 300 ° C
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH