This invention relates to a preparation method of an ester compound that can reduce energy consumption due to convenient post-treatment process, and simultaneously, can produce products of high purities.

This invention relates to a preparation method of an ester compound that can reduce energy consumption due to convenient post-treatment process, and simultaneously, can produce products of high purities.

A method for improving the hue of recycled BHET is provided. The method includes: providing a recycled polyester fabric; using a chemical de-polymerization liquid to chemically depolymerize the recycled polyester fabric to form a de-polymerization product; distilling out the chemical de-polymerization liquid from the de-polymerization product by evaporation; dissolving the BHET in water to form a aqueous phase liquid; adding an activated carbon material to the aqueous phase liquid to adsorb impurities; and cooling the aqueous phase liquid to crystallize the BHET from the aqueous phase liquid to obtain a recycled BHET.

A method for improving the hue of recycled BHET is provided. The method includes: providing a recycled polyester fabric; using a chemical de-polymerization liquid to chemically depolymerize the recycled polyester fabric to form a de-polymerization product; distilling out the chemical de-polymerization liquid from the de-polymerization product by evaporation; dissolving the BHET in water to form a aqueous phase liquid; adding an activated carbon material to the aqueous phase liquid to adsorb impurities; and cooling the aqueous phase liquid to crystallize the BHET from the aqueous phase liquid to obtain a recycled BHET.

A method for improving a recovery rate of recycled bis(2-hydroxyethyl) terephthalate (BHET) is provided, which includes: providing a recycled polyester fabric; using a chemical de-polymerization liquid to chemically depolymerize the recycled polyester fabric, so as to form a de-polymerization product containing BHET; dissolving the BHET in water to form a aqueous phase liquid; cooling the aqueous phase liquid from a dissolution temperature to a first crystallization temperature, so as to crystallize at least a part of the BHET; and cooling the aqueous phase liquid from the first crystallization temperature to a second crystallization temperature, so as to crystallize at least another part of the BHET.

A method for improving a recovery rate of recycled bis(2-hydroxyethyl) terephthalate (BHET) is provided, which includes: providing a recycled polyester fabric; using a chemical de-polymerization liquid to chemically depolymerize the recycled polyester fabric, so as to form a de-polymerization product containing BHET; dissolving the BHET in water to form a aqueous phase liquid; cooling the aqueous phase liquid from a dissolution temperature to a first crystallization temperature, so as to crystallize at least a part of the BHET; and cooling the aqueous phase liquid from the first crystallization temperature to a second crystallization temperature, so as to crystallize at least another part of the BHET.

The present disclosure relates to the formation of dimethyl terephthalate (DMT). The present invention also relates to the depolymerization of polyethylene terephthalate (PET) and the recovery of dimethyl terephthalate (DMT).

The present disclosure relates to the formation of dimethyl terephthalate (DMT). The present invention also relates to the depolymerization of polyethylene terephthalate (PET) and the recovery of dimethyl terephthalate (DMT).

The present disclosure relates to the formation of dimethyl terephthalate (DMT). The present invention also relates to the depolymerization of polyethylene terephthalate (PET) and the recovery of dimethyl terephthalate (DMT).

A compound includes, in a molecule, a structure A represented by the following A and a structure B represented by the following B, in which the compound includes two or more of the structures B in the molecule. A: A structure in which at least one or more aromatic ring structures are included and a total number of π electrons of the aromatic ring structure in the molecule is 8 or more. However, an aryl amine structure represented by a predetermined structure is excluded. B: A fluorine-containing terminal structure represented by a predetermined structural formula.