nylon 6 10 and the reaction product of the residue of adipic acid and hexamethylene diamine is nylon 6 6 nylon 6 12 is another nylon which benefits from the invention nylon 6 is a special type of polyamide having the formula of h 2 n u2014 ch 2 5 u2014 cooh and is made by the opening of caprolactam ring and then reacting or polymerizing the resulting amino caproic acid with itself although nylon 6 is a preferred polyamide polymer the most preferred polyamide polymer is the reaction product of the residues of adipic acid and m xylylene diamine known as poly m xylylene adipamide this product is commercially known as mxd6 or nylon mxd6 the reaction is preferably carried out in a stainless steel reactor for 30 120 minutes and can be performed continuously or discontinuously the hydrolytic depolymerization may be conducted in water mixtures of ethylene glycol and water up to 10 wt or steam which is purged into the reaction system the weight ratio of pet water is from 1 4 to 1 10 preferably 1 5 to 1 7 the depolymerization process can be carried out in air or more preferably inert gas which is most preferred the produced terephthalic acid is separated from the liquid phase by conventional methods for example after cooling by filtration terephthalic acid prepared according to the present invention contain no polyamides or amino compounds in detectable amounts the iron content is below 10 ppm the l color parameters of recovered terephthalic acid samples prepared even those prepared from the mixture of green blue and brown colored pet waste are above 82 84 the following examples illustrate but do not limit.