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