Preparation of poly(ethlene-2,6-naphthalene dicarboxylate) from dimethyl- 2,6-naphthalene dicarboxylate and methyl hydrogen 2,6- naphthalene dicarboxylate

摘要

This invention relates to a method of preparing poly(ethylene 2,6- naphthalene dicarboxylate) by the polycondensation reaction of ethylene glycol and dimethyl-2,6-naphthalene dicarboxylate, using a dimethyl-2,6- naphthalene dicarboxylate starting material which contains significant amounts of methyl hydrogen 2,6-naphthalene dicarboxylate as a contaminant. The methyl hydrogen 2,6-naphthalene dicarboxylate moiety is incorporated into the polymer structure by initially esterifying the methyl hydrogen 2, 6-naphthalene dicarboxylate acid end-group with ethylene carbonate, in the presence of an amine or ammonium catalyst, before the polyesterification/polycondensation reaction is performed.