Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C231/00—Preparation of carboxylic acid amides
  • C07C231/02—Preparation of carboxylic acid amides from carboxylic acids or from esters, anhydrides, or halides thereof by reaction with ammonia or amines
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C233/00—Carboxylic acid amides
  • C07C233/64—Carboxylic acid amides having carbon atoms of carboxamide groups bound to carbon atoms of six-membered aromatic rings
  • C07C233/67—Carboxylic acid amides having carbon atoms of carboxamide groups bound to carbon atoms of six-membered aromatic rings having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by singly-bound oxygen atoms
  • C07C233/68—Carboxylic acid amides having carbon atoms of carboxamide groups bound to carbon atoms of six-membered aromatic rings having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by singly-bound oxygen atoms with the substituted hydrocarbon radical bound to the nitrogen atom of the carboxamide group by an acyclic carbon atom
  • C07C233/69—Carboxylic acid amides having carbon atoms of carboxamide groups bound to carbon atoms of six-membered aromatic rings having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by singly-bound oxygen atoms with the substituted hydrocarbon radical bound to the nitrogen atom of the carboxamide group by an acyclic carbon atom of an acyclic saturated carbon skeleton
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C67/00—Preparation of carboxylic acid esters
  • C07C67/03—Preparation of carboxylic acid esters by reacting an ester group with a hydroxy group
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
  • C07C69/76—Esters of carboxylic acids having a carboxyl group bound to a carbon atom of a six-membered aromatic ring
  • C07C69/80—Phthalic acid esters
  • C07C69/82—Terephthalic acid esters
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

• the present invention relates to a method for producing decomposed polyester resins and a method for producing recycled polyester resins.
• PET polyethylene terephthalate
• Patent Document 1 discloses a method for depolymerizing polyester that uses a catalyst with a specific chemical structure.
• Patent Document 1 requires excessive heat energy when carrying out depolymerization. Given this background, there is still a need to develop technology that can effectively decompose polyester resin.
• the present invention aims to provide a method for effectively decomposing polyester resin.
• a method for producing a decomposition product of polyester resin includes a first step and a second step.
• a pulverized product is obtained by wet-pulverizing the polyester resin
• a reactant having one or more functional groups selected from the group consisting of a hydroxyl group, an amino group, and a mercapto group is allowed to act on the pulverized product, and an exchange reaction is carried out with the ester bonds of the polyester resin to obtain a decomposition product.
• the above aspect provides a method for effectively decomposing polyester resin.
• Method for producing decomposition product of polyester resin That is, the method for producing a decomposition product of a polyester resin according to the present embodiment is as follows. Note that, hereinafter, this method may be simply referred to as the "production method of a decomposition product”.
• a method for producing a decomposition product of a polyester resin comprising the steps of: The method includes a first step and a second step, In the first step, the polyester resin is wet-pulverized to obtain a pulverized product, In the second step, a reactant having one or more functional groups selected from the group consisting of a hydroxyl group, an amino group, and a mercapto group is allowed to act on the pulverized material to carry out an exchange reaction with the ester bonds of the polyester resin, thereby obtaining the decomposition product.
• a decomposition product is obtained by decomposing a polyester resin as a raw material.
• the "polyester resin” is a resin having an ester bond in the main chain, and typically has a structure in which a dibasic acid and a polyol compound are condensed.
• the dibasic acid here is selected from compounds having two carboxyl groups in the chemical structure.
• aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-2,2'-dicarboxylic acid, biphenyl-3,3'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, bis(4,4'-carboxyphenyl)methane, anthracenedicarboxylic acid, and 4,4'-diphenyletherdicarboxylic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and 4,4'-dicyclohexyldicarboxylic acid; and aliphatic dicarboxylic acids such as adipic acid, sebacic acid,
• the polyol compound is selected from compounds having two or more hydroxyl groups in the chemical structure. Specifically, aliphatic or alicyclic diols having 2 to 20 carbon atoms, bisphenol derivatives, and the like can be used. More specific examples include ethylene glycol, propylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, decamethylene glycol, cyclohexanedimethanol, 4,4'-dicyclohexylhydroxymethane, 4,4'-dicyclohexylhydroxypropane, and ethylene oxide adduct diol of bisphenol A. As a more typical example, the polyol compound may be a glycol compound.
• the polyester resin described above is preferably a resin that is widely available.
• the polyester resin may be polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polyethylene furanoate (PEF), etc.
• the decomposition product obtained by the method for producing a decomposition product of this embodiment is typically a condensation product of the dibasic acid described above and the reactant used in the second step.
• the reactant has one or more functional groups selected from the group consisting of hydroxyl groups, amino groups, and mercapto groups, so the decomposition product obtained may have one or more groups selected from the group consisting of ester groups, amide groups, and thioester groups in its chemical structure.
• the decomposition product may be a low molecular weight compound (for example, a molecular weight of 1500 or less).
• such decomposition products may be used for various purposes. For example, they may be used as a raw material for obtaining other chemical products, or as a raw material for obtaining the recycled polyester resin described below.
• the first step is a step of obtaining a pulverized product by wet pulverizing a polyester resin.
• wet grinding refers to a method of grinding an object in a liquid such as water or an organic solvent.
• examples of such treatments include wet grinding methods such as grinding stone type (grindstone type), cutting blade type, pounding type, media stirring type, compression type, impact type, and grinding type, as well as combinations of these.
• the wet grinding may be a combination of one or more methods selected from the group consisting of a bead mill, a ball mill, and a planetary mill. From the viewpoint of realizing an industrially advantageous process, it is preferable that in the first step, the polyester resin is ground using a bead mill to obtain a ground product.
• the inventors have found through their research that when reacting polyester resin with a reactant to obtain a decomposition product, the reaction efficiency can be dramatically improved by first obtaining a pulverized product and then reacting with the reactant.
• the reaction efficiency can be dramatically improved by first obtaining a pulverized product and then reacting with the reactant.
• the raw material is polyester resin, it may not be possible to pulverize it effectively even when shearing is applied.
• wet pulverization in the first step a highly reactive pulverized product can be effectively obtained in the subsequent second step.
• the liquid used in wet grinding can be selected from water or known organic solvents depending on the type of polyester resin used as raw material.
• organic solvents There are no particular restrictions on the type of organic solvent, but examples that can be used include hydrocarbon solvents, alcohol solvents, ketone solvents, amide solvents, nitrile solvents, and halogen solvents.
• the organic solvent used for wet grinding is preferably a hydrocarbon solvent.
• hydrocarbon solvents include hexane, cyclohexane, heptane, petroleum ether, toluene, xylene, naphthalene, and methylnaphthalene.
• alcohol-based solvents examples include methanol, ethanol, propanol, isopropyl alcohol, butanol, and ethylene glycol.
• ketone-based solvents examples include acetone, methyl ethyl ketone, and cyclohexanone.
• amide-based solvents examples include N,N-dimethylformamide and N,N-dimethylacetamide.
• nitrile-based solvents examples include acetonitrile.
• halogen-based solvents examples include methylene chloride and chloroform.
• the constituent material of the beads can be set appropriately.
• the beads may be made of zirconia, iron, alumina, etc., but there is no limitation thereto, and any known beads that can be applied to a bead mill may be used.
• the particle size of the pulverized material obtained in the first step may be set appropriately depending on the type of polyester resin, the reaction conditions in the second step, and the like.
• the primary particle size of the pulverized material is preferably 100 ⁇ m or less, more preferably 70 ⁇ m or less, even more preferably 50 ⁇ m or less, even more preferably 30 ⁇ m or less, and particularly preferably 10 ⁇ m or less.
• the first step may include a step of filtering the slurry obtained after wet grinding.
• the ground product when obtaining the ground product to be applied to the second step, the ground product may have a controlled particle size. This filtration is typically performed by passing the result (slurry) obtained by wet grinding through a filter (mesh).
• the pore size of the filter (mesh) can be set appropriately, but from the viewpoint of easily obtaining a ground product with high reactivity, it may be in the range of 0.01 to 10 mm, 0.05 to 5 mm, or 0.1 to 3 mm.
• the pulverized product may be isolated to obtain the pulverized product.
• a decomposition product is obtained from the pulverized product isolated in the first step.
• Various methods may be used for isolation, but one example is a method of drying a slurry containing the polyester resin obtained by wet pulverization. The drying here may be performed under reduced pressure.
• the pulverized product may be obtained without being isolated.
• the slurry containing the pulverized product obtained by wet pulverization may be directly supplied to the subsequent second step.
• the first and second steps may be performed in the same vessel. That is, after wet pulverization of the polyester resin in one vessel, the reactant used in the second step may be added to the vessel to perform an exchange reaction with the polyester resin.
• the first step may also be performed in the presence of the reactant used in the second step.
• the pulverized product obtained by wet pulverizing the polyester resin is subjected to the exchange reaction on the spot.
• the method for producing a decomposition product of this embodiment may include various embodiments as described above.
• the second step is a step in which a reactant having one or more functional groups selected from the group consisting of a hydroxyl group, an amino group, and a mercapto group is allowed to act on the pulverized material to carry out an exchange reaction with the ester bond of the polyester resin, thereby obtaining a decomposition product.
• the second step is to perform an exchange reaction on the ester groups in the polyester resin to obtain a decomposition product that may have one or more groups selected from the group consisting of ester groups, amide groups, and thioester groups in its chemical structure.
• the second step may be performed by appropriately selecting conditions from among conditions under which the exchange reaction on the ester groups proceeds.
• the second step is a step in which the obtained pulverized material is subjected to a predetermined exchange reaction, but the business entity that performs the exchange reaction and the business entity that performs the wet pulverization do not necessarily have to be the same.
• obtaining a pulverized material produced by another business entity and then performing an exchange reaction on the pulverized material can also be treated as an example of this embodiment.
• the reactant used in the second step for example, the following compounds can be used.
• the reactant having a hydroxyl group examples include aliphatic alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol, ethylene glycol, and propylene glycol; aromatic alcohols such as phenol, biphenol, and bisphenol A; and alicyclic alcohols such as cyclohexanol and methylhexanol.
• Examples of the reactant having an amino group include ammonia; monoalkylamines such as methylamine, ethylamine, and propylamine; dialkylamines such as diethylamine and dipropylamine; and alcoholamines such as ethanolamine and diethanolamine.
• the amino group used in this embodiment may be represented as -NH2 or -NHR.
• R is an organic group. That is, the reactant used in this embodiment may be ammonia, a primary amine compound, or a secondary amine compound.
• Examples of the reactant having a mercapto group that can be used include aliphatic thiols such as methylthiol, ethylthiol, propylthiol, and ethylenedithiol; aromatic thiols such as thiophenol; and alicyclic thiols such as cyclohexanethiol.
• the reactant may be a monofunctional compound having one of the above-mentioned functional groups, or a polyfunctional compound having two or more of the above-mentioned functional groups. However, it is preferable that the reactant is a monofunctional compound because it is easier to control the reaction. In addition, a compound having a combination of the above-mentioned hydroxyl group, amino group, and mercapto group may be used as the reactant.
• a catalyst may be used in the second step.
• the catalyst here is an agent that promotes the above-mentioned exchange reaction, and is selected from among known agents suitable for such purposes.
• the second step may be performed in the presence of a catalyst that is different from the reactant and is selected from an acid and a base.
• the acid used as the catalyst may be a Bronsted acid or a Lewis acid. These acids typically accept electrons from the oxygen atoms of the ester groups of the polyester resin, thereby promoting the polarization of the ester groups and accelerating the transesterification reaction.
• Examples of the Bronsted acid that can be used include sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid.
• Examples of the Lewis acid that can be used include complexes of ligands and metal elements such as titanium, zirconium, lanthanum, hafnium, germanium, tin, and zinc, and oxides of these metal elements.
• the type of ligand is not particularly limited, and may be, for example, ⁇ -diketones such as acetylacetone, ketoesters, hydroxycarboxylic acids, ketoalcohols, or aminoalcohols.
• the base used as a catalyst typically donates electrons to the carbon atom of the ester group in the polyester resin. This promotes polarization of the ester group and accelerates the transesterification reaction.
• bases that can be used as catalysts include hydroxides of alkali metals or alkaline earth metals such as sodium hydroxide, potassium hydroxide, and magnesium hydroxide; carbonates and hydrogen carbonates of alkali metals or alkaline earth metals such as sodium hydrogen carbonate, potassium carbonate, and calcium hydrogen carbonate; alkoxides or phenoxides of alkali metals or alkaline earth metals such as lithium ethoxide, sodium methoxide, potassium methoxide, magnesium methoxide, and sodium phenoxide; oxides of alkali metals or alkaline earth metals such as calcium oxide; ammonia; ammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra-n-buty
• the exchange reaction can be carried out in various solvents.
• the solvent that can be used in the second step may be appropriately selected from known solvents.
• the solvent may be one or more of alcohol-based solvents, ketone-based solvents, ester-based solvents, ether-based solvents, ether ester-based solvents, glycol ether-based solvents, amide-based solvents, carbonate-based solvents, hydrocarbon-based solvents, nitrile-based solvents, nitrogen-containing compound-based solvents, halogen-based solvents, etc.
• Examples of the alcohol-based solvent include methanol, ethanol, isopropanol, 1-butanol, tertiary butanol, isobutanol, and diacetone alcohol.
• Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and diisobutyl ketone.
• ester solvent examples include ethyl acetate, methyl acetate, butyl acetate, methoxybutyl acetate, cellosolve acetate, amyl acetate, n-propyl acetate, isopropyl acetate, methyl lactate, ethyl lactate, and butyl lactate.
• ether solvents include diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether, tetrahydrofuran, methyltetrahydrofuran, tetrahydropyran, methyltetrahydropyran, and dioxane.
• ether ester solvents examples include 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, and methyl methoxypropionate.
• glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, and butyl cellosolve (ethylene glycol monobutyl ether).
• Examples of the amide solvent include N-methylpyrrolidone and N,N-dimethylformamide.
• the carbonate solvent include propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.
• Examples of the hydrocarbon solvent include hexane, cyclohexane, heptane, petroleum ether, toluene, xylene, naphthalene, and methylnaphthalene.
• An example of the nitrile solvent is acetonitrile.
• the nitrogen-containing compound solvent include pyridine, methylpyridine, lutidine, trimethylamine, and triethylamine.
• Examples of halogen-based solvents include methylene chloride and chloroform. Of course, the solvents that can be used in the second step are not limited to these.
• the temperature conditions when the second step is carried out can be set appropriately.
• the second step since the pulverized material used in the second step is itself highly reactive, the second step may be carried out at a low temperature. This makes it possible to obtain a decomposition product without requiring excessive heat energy from the outside.
• the exchange reaction may be carried out at 100°C or less, 80°C or less, or 60°C or less. Note that the temperature here refers to the internal temperature in the reaction system.
• a method for producing a recycled polyester resin comprising the steps of: A third step is provided, In the third step, a polyol compound is reacted with the decomposition product obtained by the above-mentioned production method to obtain the recycled polyester resin.
• the above-mentioned method for producing recycled polyester resin includes a third step.
• a polyol compound is reacted with the decomposition product obtained in the above-mentioned method for producing the decomposition product to obtain a polyester resin separately.
• the polyol compound may be, for example, the polyol compound shown in the section [Method for producing decomposition product of polyester resin].
• the above-mentioned recycled polyester resin may have the same or different chemical structure as the polyester resin used as a raw material in the method for producing the decomposition product.
• the polyol units that can constitute the polyester resin that is the raw material in the method for producing the decomposition product and the polyol units that can constitute the recycled polyester resin may be the same or different.
• the third step involves reacting the decomposition product with a polyol compound, typically through an exchange reaction, to obtain recycled polyester resin, but the reaction conditions can be set appropriately depending on the type of decomposition product and the type of polyol compound.
• a method for producing a decomposition product of a polyester resin comprising the steps of: The method includes a first step and a second step, In the first step, a pulverized product of the polyester resin is obtained, wherein the primary particle size of the pulverized material is 100 ⁇ m or less, In the second step, a reactant having one or more functional groups selected from the group consisting of a hydroxyl group, an amino group, and a mercapto group is allowed to act on the pulverized material to carry out an exchange reaction with the ester bonds of the polyester resin, thereby obtaining the decomposition product.
• the primary particle size of the pulverized material is set to a predetermined value or less, but the pulverization method in the first step is not necessarily limited to wet pulverization. Even with this manufacturing method of the decomposition product, it can be said that an effective decomposition product can be manufactured, in that pulverized material with a small particle size is provided to the second step.
• a method for producing a decomposition product of a polyester resin comprising a first step and a second step, in which the polyester resin is wet-pulverized to obtain a pulverized product, and in which a reactant having one or more functional groups selected from the group consisting of a hydroxyl group, an amino group, and a mercapto group is allowed to act on the pulverized product to perform an exchange reaction with the ester bonds of the polyester resin to obtain the decomposition product.
• the polyester resin is pulverized using a bead mill to obtain a pulverized product.
• the first step includes a step of filtering the slurry obtained after wet grinding.
• the exchange reaction is carried out in the presence of a catalyst selected from an acid and a base, which is different from the reactant.
• polyester resin is polyethylene terephthalate (PET).
• a method for producing a recycled polyester resin comprising a third step, in which the recycled polyester resin is obtained by reacting the decomposition product obtained by the production method described in any one of (1) to (8) above with a polyol compound.
• the recycled polyester resin is obtained by reacting the decomposition product obtained by the production method described in any one of (1) to (8) above with a polyol compound.
• a pulverized product was obtained using polyethylene terephthalate (PET) obtained from Sigma-Aldrich. Specifically, 5 g of polyethylene terephthalate and 100 mL of a solvent were charged into a ball mill device, and pulverization of polyethylene terephthalate was attempted under the conditions of a rotation speed of 2500 rpm and a pulverization time of 3 hours.
• PET polyethylene terephthalate
• "Easy Nano RMB II type” manufactured by Imex Co., Ltd. was used as the ball mill device, and 160 mL of zirconia beads were used as the beads.
• the pulverization was performed while cooling the container in the device with cooling water at 10 ° C.
• the mixture was filtered through a ⁇ 0.5 mm mesh to obtain a slurry in which the pulverized product with small particle size was dispersed in the solvent.
• the obtained slurry was subjected to solvent removal using a rotary evaporator to obtain a solid pulverized product.
• pulverized material 1 the pulverized material obtained when toluene was used as the solvent
• pulverized material 2 the pulverized material obtained when acetonitrile was used as the solvent
• Table 1 shows the number average molecular weight (Mn), weight average molecular weight (Mw), dispersity (Mw/Mn), and peak top molecular weight of each pulverized material measured by GPC, as well as the measured primary particle size of the pulverized material.
• Comparative Example 1 shows an example in which an exchange reaction was carried out using polyethylene terephthalate pellets of about 5 mm that had not been subjected to a beer mill treatment.
• the evaluation was performed by quantifying how much dimethyl terephthalate (DMT) was generated based on the polyethylene terephthalate used by gas chromatography.
• DMT dimethyl terephthalate
• Example 8 the exchange reaction was performed using only methanol, and in Examples 9 to 25, the exchange reaction was performed using a mixed solvent in which methanol and a co-solvent were in a ratio of 1:1.
• aminolysis represented by the following chemical formula (2) was carried out using 2-aminoethanol as a reactant.
• a solvent was added so that the ratio of polyethylene terephthalate (ground material 1) used was 0.1M, and a specified amount of tetramethylammonium methoxide was added to the polyethylene terephthalate as a catalyst before heating to evaluate how much polyethylene terephthalate was converted to bis(2-hydroxyethyl)terephthalamide (BHETA).
• the evaluation was performed by quantifying by gas chromatography how much bis(2-hydroxyethyl)terephthalamide (BHETA) was produced, based on the polyethylene terephthalate used.
• the solvents and various conditions used are as shown in Table 6.
• a solvent was added so that the ratio of polyethylene terephthalate (ground material 1) used was 0.1M, and a specified amount of tetramethylammonium methoxide was added to the polyethylene terephthalate as a catalyst before heating to evaluate how much polyethylene terephthalate was converted to bis(2-hydroxyethyl) terephthalate (BHET).
• the evaluation was performed by quantifying by gas chromatography how much bis(2-hydroxyethyl) terephthalate (BHET) was produced, based on the polyethylene terephthalate used.
• the solvents and various conditions used are as shown in Table 7.

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