Abstract: A process for preparing a dialkylester of a naphthalenedicarboxylic acid comprising directing a liquid phase reaction mixture comprising a low molecular weight alcohol, a naphthalenedicarboxylic acid, a dialkylester of a naphthalenedicarboxylic acid, and a polyethylene naphthalate containing material, at a given temperature and pressure through series arranged reaction zones and subsequently removing a product comprising a dialkylester formed by the reaction of the naphthalenedicarboxylic acid and the polyethylene naphthalate containing material with the low molecular weight alcohol from a reaction zone. This invention is also directed to a process for preparing a purified dialkylester of a naphthalenedicarboxylic acid comprising a series of crystallization and distillation steps, and combinations thereof.

Abstract: A process for preparing a dialkylester of a naphthalenedicarboxylic acid comprising directing a liquid phase reaction mixture comprising a low molecular weight alcohol, a naphthalenedicarboxylic acid, a dialkylester of a naphthalenedicarboxylic acid, and a polyethylene naphthalate containing material, at a given temperature and pressure through series arranged reaction zones and subsequently removing a product comprising a dialkylester formed by the reaction of the naphthalenedicarboxylic acid and the polyethylene naphthalate containing material with the low molecular weight alcohol from a reaction zone. This invention is also directed to a process for preparing a purified dialkylester of a naphthalenedicarboxylic acid comprising a series of crystallization and distillation steps, and combinations thereof.

Abstract: The synthesis of dimethyl-1,5-naphthalenedicarboxylate and polymers and articles formed therefrom is disclosed, as well as applications for dimethyl-1,5-naphthalenedicarboxylate, its corresponding acid 1,5-NDA, and various synthesis intermediates.

Abstract: The synthesis of dimethyl-1,5-naphthalenedicarboxylate and polymers and articles formed therefrom is disclosed, as well as applications for dimethyl-1,5-naphthalenedicarboxylate, its corresponding acid 1,5-NDA, and various synthesis intermediates.

Abstract: Processes are disclosed for recovery and purification of dibasic aromatic acids from waste polyester film, fiber, bottles, manufacturing residues, and other manufactured articles. The processes comprises: depolymerizing polyester resin in a solvent under conditions suitable for hydrolysis of ester bonds to obtain a mixture containing a solution of aromatic acid and impurities consisting of alcohol and/or other components of the resin; burning impurities in a liquid-phase oxidation with an oxygen-containing gas in the presence of an oxidation catalyst at elevated pressures and temperatures, to obtain an oxidation product containing the desired aromatic acid; and crystallizing and separating from the oxidation system a resulting crude dibasic aromatic acid.

Abstract: High quality linear polyester resin is prepared by reacting in a first step or zone 2,6-naphthalene dicarboxylic acid with a molten prepolymer derived from a glycol and 2,6-naphthalene dicarboxylic acid to form a low molecular weight product of the first step or zone; reacting this resultant product with a glycol in at least two successive steps or zones of glycol addition to form prepolymer; and polymerizing at least a portion of the resulting prepolymer to form polyester resin which exhibits midpoint glass transition temperatures above about 123.degree. C. The resulting prepolymer is particularly suitable for reaction with the 2,6-naphthalene dicarboxylic acid in the first step or zone. Advantageously, at least a portion of the prepolymer is, therefore, returned to the first step or zone.