Recycling polyethylene naphthalate containing materials in a process to produce diesters

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.