{HEAD ~ This specific carbonate concentration} improves the settling characteristics of the catalyst and reduces catalyst carryover into {TAIL ~ the crude hexamethylene diamine} during decantation 
{ HEAD ~ This specific carbonate concentration } improves the settling characteristics of the catalyst and reduces catalyst carryover into { TAIL ~ the crude hexamethylene diamine } during decantation
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH