The present invention relates to a method for production of terephthalic acid using high polymerization degree polyethylene terephthalate, which includes: (i) introducing high polymerization degree polyethylene terephthalate having an intrinsic viscosity of 0.75 dl/g or more into a continuous reactor, and then heating and pressurizing the same to prepare a fluidal polyethylene terephthalate; (ii) introducing a mixed slurry prepared by mixing an alkaline material containing an alkali-metal, a weak acid salt of the alkali-metal and ethylene glycol together into an internal position of the continuous reactor, through which the fluidal polyethylene terephthalate passes, and implementing neat reaction of the fluidal polyethylene terephthalate with the mixed slurry in the continuous reactor to prepare alkali-metal terephthalate; and (iii) dissolving the prepared alkali-metal terephthalate in water, removing foreign substances through filtration and centrifugation, adding acid to the alkali-metal terephthalate dissolved in water and reacting the same, thereby producing terephthalic acid.

The present invention relates to a method for production of terephthalic acid using high polymerization degree polyethylene terephthalate, which includes: (i) introducing high polymerization degree polyethylene terephthalate having an intrinsic viscosity of 0.75 dl/g or more into a continuous reactor, and then heating and pressurizing the same to prepare a fluidal polyethylene terephthalate; (ii) introducing a mixed slurry prepared by mixing an alkaline material containing an alkali-metal, a weak acid salt of the alkali-metal and ethylene glycol together into an internal position of the continuous reactor, through which the fluidal polyethylene terephthalate passes, and implementing neat reaction of the fluidal polyethylene terephthalate with the mixed slurry in the continuous reactor to prepare alkali-metal terephthalate; and (iii) dissolving the prepared alkali-metal terephthalate in water, removing foreign substances through filtration and centrifugation, adding acid to the alkali-metal terephthalate dissolved in water and reacting the same, thereby producing terephthalic acid.

A method for depolymerizing a polyester may comprise heating a polyester at a temperature and for a period of time in the presence of a supported metal-dioxo catalyst, optionally, in the presence of H.sub.2, to induce hydrogenolysis of ester groups in the polyester and provide monomers of the polyester.

A method for depolymerizing a polyester may comprise heating a polyester at a temperature and for a period of time in the presence of a supported metal-dioxo catalyst, optionally, in the presence of H.sub.2, to induce hydrogenolysis of ester groups in the polyester and provide monomers of the polyester.

Processes for the oxidation of carbohydrate dehydration products, such as furanics that can be oxidized to the bio-based monomer 2,5-furandicarboxylic acid (FDCA), are disclosed, according to which certain co-feeds, having been discovered to impart a beneficial reaction stabilizing effect, are oxidized together with the carbohydrate dehydration products. This can advantageously counteract, in whole or in part, detrimental effects of humin impurities present in oxidation feed, with such impurities having been generated as byproducts of the upstream dehydrating step. An important co-feed is para-xylene that can be co-oxidized to form the petroleum-based monomer terephthalic acid (TPA), such that co-processing can beneficially yield two valuable monomers, while improving performance, particularly in terms of reaction stability, over comparable processes in which only the first monomer is produced. Related aspects involve opportunities for retrofitting existing monomer production facilities to enable co-processing of carbohydrate dehydration products that can lead to the above-noted advantages.

Processes for the oxidation of carbohydrate dehydration products, such as furanics that can be oxidized to the bio-based monomer 2,5-furandicarboxylic acid (FDCA), are disclosed, according to which certain co-feeds, having been discovered to impart a beneficial reaction stabilizing effect, are oxidized together with the carbohydrate dehydration products. This can advantageously counteract, in whole or in part, detrimental effects of humin impurities present in oxidation feed, with such impurities having been generated as byproducts of the upstream dehydrating step. An important co-feed is para-xylene that can be co-oxidized to form the petroleum-based monomer terephthalic acid (TPA), such that co-processing can beneficially yield two valuable monomers, while improving performance, particularly in terms of reaction stability, over comparable processes in which only the first monomer is produced. Related aspects involve opportunities for retrofitting existing monomer production facilities to enable co-processing of carbohydrate dehydration products that can lead to the above-noted advantages.

Processes for the oxidation of carbohydrate dehydration products, such as furanics that can be oxidized to the bio-based monomer 2,5-furandicarboxylic acid (FDCA), are disclosed, according to which certain co-feeds, having been discovered to impart a beneficial reaction stabilizing effect, are oxidized together with the carbohydrate dehydration products. This can advantageously counteract, in whole or in part, detrimental effects of humin impurities present in oxidation feed, with such impurities having been generated as byproducts of the upstream dehydrating step. An important co-feed is para-xylene that can be co-oxidized to form the petroleum-based monomer terephthalic acid (TPA), such that co-processing can beneficially yield two valuable monomers, while improving performance, particularly in terms of reaction stability, over comparable processes in which only the first monomer is produced. Related aspects involve opportunities for retrofitting existing monomer production facilities to enable co-processing of carbohydrate dehydration products that can lead to the above-noted advantages.

The present invention provides a process for producing a compound represented by formula (I), comprising the steps of (a) reacting a compound represented by formula (II) with dimethyl sulfate in the presence of an alkali carbonate in a aqueous ketone solvent to obtain the compound represented by formula (I) as a crystalline material, and (b) washing the crystalline material with heated water at 30 to 100° C. and then further washing with an organic solvent at 30 to 80° C.

The present invention provides a process for producing a compound represented by formula (I), comprising the steps of (a) reacting a compound represented by formula (II) with dimethyl sulfate in the presence of an alkali carbonate in a aqueous ketone solvent to obtain the compound represented by formula (I) as a crystalline material, and (b) washing the crystalline material with heated water at 30 to 100° C. and then further washing with an organic solvent at 30 to 80° C.

This invention relates to a process for preparing succinic acid and succinate ester from a succinic acid salt in fermentation broth. In the first stage of this invention, renewable carbon resources are utilized to produce succinic acid through biological fermentation. The succinic acid salt in the fermentation process is subjected to double displacement reaction with a strong acid leading to release of succinic acid. Succinic acid is recovered by fractional crystallization integrated with simulated moving bed chromatography to produce succinic acid and succinate ester.