A method for producing a decolorized polyester according to the present invention includes: a step of preparing a polyester colored with a colorant, and a decolorizing agent containing a glycol ether-type compound having a boiling point at atmospheric pressure of 160° C. or higher; and a step of removing the colorant, by bringing the decolorizing agent into contact at least once with the colored polyester while heating the decolorizing agent to a temperature equal to or lower than a melting point of the polyester, to thereby obtain the decolorized polyester.
[Problem] To provide: a method for producing BHET, by which BHET can be produced in a simple manner from PE waste materials; and a method for producing recycled PET using said BHET as a raw material. [Solution] One embodiment of the present invention provides a method for producing BHET. This production method includes: a depolymerization step for mixing PE waste materials, MEG and a depolymerization catalyst, and depolymerizing the PE waste materials to obtain a depolymerization product containing crude BHET; a washing step for cooling the depolymerization product, adding a washing medium that is different from MEG, and transferring at least some impurities other than PE contained in the depolymerization product to the washing medium so as to remove these impurities from the depolymerization product; a concentration step for removing low boiling point components containing at least the washing medium from the washed depolymerization product so as to concentrate the crude BHET; and a recovery step for recovering BHET from the concentrated crude BHET by means of distillation so as to obtain high purity BHET having a higher purity than the crude BHET.
C08J 11/24 - Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with organic material by treatment with organic oxygen-containing compounds containing hydroxyl groups
3.
Method for producing decolored polyester, decolored polyester, and decoloring agent
A method for producing a decolorized polyester according to the present invention includes: a step of preparing a polyester colored with a colorant, and a decolorizing agent containing a glycol ether-type compound having a boiling point at atmospheric pressure of 160° C. or higher; and a step of removing the colorant, by bringing the decolorizing agent into contact at least once with the colored polyester while heating the decolorizing agent to a temperature equal to or lower than a melting point of the polyester, to thereby obtain the decolorized polyester.
[Problem] To provide a method for producing high-purity bis(2-hydroxyethyl) terephthalate (BHET), by which high-purity BHET can be easily produced from colored polyester waste. [Solution] A method for producing high-purity BHET according to the present invention comprises: a depolymerization step in which colored polyester waste is depolymerized to obtain a depolymerization product including colored crude BHET; a concentration step in which low-boiling ingredients contained in the depolymerization product are removed to concentrate the BHET; a recovery step in which the BHET is recovered from the crude BHET to obtain medium-purity BHET; a crystallization separation step in which the medium-purity BHET is subjected to crystallization in a decoloring solvent and the crystals are separated, by solid-liquid separation, from the colorant-containing solvent ingredient, thereby obtaining purified BHET; and a solvent removal step in which the solvent remaining in the crystals of the purified BHET is removed to obtain high-purity BHET.
C08J 11/16 - Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with inorganic material
C07C 67/52 - SeparationPurificationStabilisationUse of additives by change in the physical state, e.g. crystallisation
C07C 67/54 - SeparationPurificationStabilisationUse of additives by change in the physical state, e.g. crystallisation by distillation
[Problem] To provide a method for producing bis-(2-hydroxyethyl)terephthalate (BHET), the method being capable of simply producing a BHET with high purity from a colored polyester waste. [Solution] A method for producing a BHET according to the present invention comprises: a depolymerization step for mixing a polyester waste colored by a pigment, with a monoethylene glycol and a depolymerization catalyst, and depolymerizing the polyester waste to obtain a depolymerized product containing a crude colored BHET; a pigment decomposition/removal step for adding a pigment decomposition agent to the depolymerized product and cooling and centrifuging the resultant mixture, thereby separating extracted solids and the decomposed product of the pigment and removing at least a portion of the decomposed product from the depolymerized product; a concentration step for removing a low boiling-point component containing monoethylene glycol from the depolymerized product from which at least a portion of the decomposed product has been removed, and concentrating the crude BHET; and a collection step for collecting, by distillation, BHET from the concentrated crude BHET to obtain a BHET having higher purity than the crude BHET.
C08J 11/00 - Recovery or working-up of waste materials
C08J 11/08 - Recovery or working-up of waste materials of polymers without chemical reactions using selective solvents for polymer components
C08J 11/10 - Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
C08J 11/16 - Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with inorganic material
C07C 67/52 - SeparationPurificationStabilisationUse of additives by change in the physical state, e.g. crystallisation
[Problem] To provide: a method for producing a decolored polyester in which the colorant is removed from a colorant-colored polyester to efficiently obtain the decolored polyester; the decolored polyester; and a decoloring agent usable for producing the decolored polyester. [Solution] The method for producing a decolored polyester of the present invention is characterized by comprising: a step in which a polyester colored with a colorant and a decoloring agent comprising a glycol ether compound having a boiling point at atmospheric pressure of 160°C or higher are prepared; and a step in which the decoloring agent is heated to a temperature not higher than the melting point of the polyester and is brought into contact at least once with the colored polyester to thereby remove the colorant and obtain the decolored polyester.
C08L 67/00 - Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chainCompositions of derivatives of such polymers
7.
PRODUCTION METHOD FOR BIS(2-HYDROXYETHYL) 1,4-CYCLOHEXANEDICARBOXYLATE
[Problem] To provide a bis(2-hydroxyethyl) 1,4-cyclohexanedicarboxylate (BHEC) production method that makes it possible to obtain BHEC simply and in high yields. [Solution] This BHEC production method is characterized in that bis(2-hydroxyethyl) terephthalate (BHET) is reacted with hydrogen gas in the presence of a ruthenium catalyst to hydrogenate the benzene ring of the BHET. The hydrogenation of the benzene ring of the BHET is preferably performed at a hydrogen gas pressure of 1–10 MPa and a temperature of 80℃–200℃.
C07C 67/303 - Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by hydrogenation of unsaturated carbon-to-carbon bonds
C07C 69/75 - Esters of carboxylic acids having an esterified carboxyl group bound to a carbon atom of a ring other than a six-membered aromatic ring of acids with a six-membered ring
[Problem] To provide a trans-bis(2-hydroxyalkyl) cyclohexanedicarboxylate (trans-BHAC) production method that makes it possible to obtain trans-BHAC simply and in high yields. [Solution] This trans-BHAC production method is characterized in that trans-BHAC is obtained by isomerizing cis-bis(2-hydroxyalkyl) cyclohexanedicarboxylate (cis-BHAC) by contact with a basic oxide. The isomerization is preferably performed at a temperature of 160℃–300℃. The weight ratio of the cis-BHAC and the basic oxide is preferably 100:0.1–100:10.
C07C 67/333 - Preparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by isomerisationPreparation of carboxylic acid esters by modifying the acid moiety of the ester, such modification not being an introduction of an ester group by change of size of the carbon skeleton
C07C 69/75 - Esters of carboxylic acids having an esterified carboxyl group bound to a carbon atom of a ring other than a six-membered aromatic ring of acids with a six-membered ring
B01J 23/02 - Catalysts comprising metals or metal oxides or hydroxides, not provided for in group of the alkali- or alkaline earth metals or beryllium
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