1222results about "Preparation by ester-hydroxy reaction" patented technology

The invention belongs to the technical field of PET (Polyethylene Terephthalate) recovery, and particularly relates to a method for assisting methanol alcoholysis of waste PET by using an ester solvent. The method comprises the following steps: by taking waste PET as a raw material, methanol as a solvent and an ester solvent as a cosolvent, catalyzing and depolymerizing the waste PET under the action of an organic strong alkali catalyst to obtain an alcoholysis product, and further separating and purifying the alcoholysis product to obtain DMT and high-value byproducts. The method is mild in reaction condition and rapid in reaction process, the catalyst does not contain metal, and the subsequent purification process can be simplified.

A process for chemically recycling waste polyethylene terephthalate (PET) carpet fibers. The process comprises providing a waste carpet fiber composition comprising at least 75 wt % of PET and 6 wt % or less of ash; reacting the waste carpet fiber composition with methanol to produce a depolymerized poly ester mixture comprising polyester oligomers, dimethyl terephthalate (DMT), and ethylene glycol (EG); and recovering the DMT and the EG from the depolymerized polyester mixture.

The invention relates to the technical field of chemical degradation of waste polyester, and discloses a titanium-silicon compound catalyst, a preparation method thereof and a method for depolymerizing polyethylene glycol terephthalate. The preparation method of the titanium-silicon compound catalyst comprises the following steps: (1) preparing a titanium compound, an orthosilicate compound and a solvent, and reacting with an organic acid solution to obtain a solution; and (2) carrying out post-treatment on the solution to obtain the titanium-silicon compound catalyst. The catalyst has the characteristics of high PET depolymerization rate, low polymerization degree in a depolymerization product, high purity of a depolymerization product bis (2-hydroxyethyl) terephthalate (BHET) and low titanium residue in a target product in a PET degradation reaction. The BHET obtained by the method disclosed by the invention can be directly used for preparing PET polyester products or other high-added-value products, and closed-loop cyclic utilization of PET is realized.

Processes for recovering dialkyl terephthalates. The processes can include exposing a polyester composition to one or more glycols to depolymerization conditions thereby providing one or more depolymerization products. The one or more depolymerization products can be exposed to an alcoholysis process to recover dialkyl terephthalate.

The invention relates to a method for purifying a monomer bis (2-hydroxyethyl) terephthalate (BHET) obtained by depolymerizing waste polyester through ethylene glycol (EG), and belongs to the technical field of polyester recycling. The BHET microwave radiation induced film evaporation separation and molecular distillation refining continuous process provided by the invention solves the problems of long process flow, poor continuity, more side reactions and low purity and yield in the direct separation and refining process of BHET in alcoholysis liquid based on a gas-liquid equilibrium separation method at present. The whole technological parameter requirement is mild, the process is short, continuity is good, the BHET purity of the product is larger than or equal to 99.0 wt%, the hue is good, and the BHET yield is larger than or equal to 80.0%. And meanwhile, the method has the advantages that EG is conveniently recycled in a system, the production process is cleaner and more environment-friendly, and the comprehensive efficiency advantage is obvious.

The invention relates to the technical field of chemical degradation of waste polyester, and discloses a titanium-rare earth compound catalyst which comprises a titanium-containing compound and a rare earth catalyst, wherein the titanium-containing compound is selected from at least one of dihydric alcohol modified alkyl titanate, alkyl titanate, dihydric alcohol titanium, titanium phosphate and organic-inorganic hybrid titanium; wherein the rare earth catalyst is selected from acetylacetone rare earth catalysts. The titanium-rare earth compound catalyst has the characteristics of high PET depolymerization rate, low polymerization degree in a depolymerization product, small catalyst dosage, high catalyst selectivity and high yield and purity of a depolymerization product bis (2-hydroxyethyl) terephthalate (BHET) in a degradation reaction of polyethylene glycol terephthalate (PET). The BHET obtained by the method disclosed by the invention can be directly used for preparing PET polyester products or other high-added-value products, and closed-loop cyclic utilization of PET is realized.

The invention belongs to the technical field of recycled polyester, and particularly relates to a waste polyester textile recycling method which comprises the following steps: decolorizing colored waste polyester textiles by adopting a decolorizing agent which is more than one of dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; the depolymerization agent is adopted to depolymerize the decolored polyester textile to obtain the terephthalate, and the depolymerization rate of the decolored polyester textile is 98.0-100%; firstly, terephthalate is converted into DMT, and then DMT, ethylene glycol, a catalyst and a functional additive are subjected to a repolymerization reaction to obtain regenerated PET. According to the method, a process of decoloring and depolymerizing sequentially is adopted, and decoloring and depolymerizing are coordinated, so that the process is simplified, the energy consumption and pollution are reduced, and the economical efficiency and sustainability of waste polyester textile recycling are improved.

The present invention relates to the recycling of textiles, and further to a method for recycling polyester blended fabrics. After the raw material containing polyester is treated, the polyester is decomposed by a catalyst at 40°C to 120°C for 0.5 to 8 hours to achieve complete depolymerization, and then separated and recycled, and the separated polyester component and other blended components are reused. The method of the present invention realizes 100% depolymerization of polyester under low temperature conditions, and the depolymerized polyester component can be easily separated from other components, so that the polyester and other temperature-sensitive fiber components in the blended fabric can be completely separated. The polyester depolymerized monomer obtained by recycling can also be used to synthesize new polyester, realizing the closed-loop recycling of different fiber components in polyester blended waste, which is of great importance for protecting the ecological environment and reducing the cost of regenerated fibers.

The invention relates to a mid-polymer-based waste functionalized PET alcoholysis regeneration method, which comprises the following steps: conveying a melt obtained by melting waste functionalized PET to a closed reactor, and introducing overheated dihydric alcohol steam into the closed reactor to depolymerize the waste functionalized PET to obtain a mid-polymer; then adding a functional monomer and dihydric alcohol into the closed reactor to carry out co-esterification with the middle polymer, sending a co-esterified product to a polymerization stage of the primary polyester to carry out a reaction, and preparing functional regenerated polyester after the reaction is finished; the polymerization degree of the middle polymer is 3-30, and the molecular weight distribution PDI is less than 3. According to the invention, depolymerization in a homogeneous state can be realized, the process that solid-phase PET is gradually depolymerized from the surface layer to the inner layer is avoided, the polymerization degree of a depolymerization product can be controlled to prepare a middle polymer, and the uniformity is increased after repolymerization.

Processes for recovering dialkyl terephthalates. The processes can include exposing a polyester composition to one or more glycols to depolymerization conditions thereby providing one or more depolymerization products. The one or more depolymerization products can be exposed to an alcoholysis process to recover dialkyl terephthalate. Optionally, the one or more glycols can be recycled and re-used in a subsequent dialkyl terephthalate recovery or other process.

Disclosed is a method for recycling a polyester blend fabric. The method includes: treating a polyester-containing raw material to be treated, subjecting a resulting treated polyester-containing raw material to polyester degradation at 40° C. to 120° C. for 0.5 h to 8 h in the presence of a catalyst to achieve complete depolymerization, separating out and recovering a polyester component, and reutilizing the polyester component and other blend components.

The invention provides a method for catalytically converting waste PET (Polyethylene Terephthalate) plastic into 1, 4-cyclohexanedimethanol by a two-step method, which comprises the following steps of: 1, hydrogenating the waste PET plastic dispersed in methanol under the action of a nickel-based catalyst to obtain dimethyl 1, 4-cyclohexane dicarboxylate; and 2, centrifugally separating the catalyst and the reaction liquid in the step 1, and hydrogenating the reaction liquid under the action of a CuMgAl catalyst to obtain the target product 1, 4-cyclohexanedimethanol. The 1, 4-cyclohexanedimethanol is a key raw material for producing high-end polyester, and has very high market requirements. Under the optimal reaction condition, the molar yield of the 1, 4-cyclohexanedimethanol can reach 83.8%, and the separation purity reaches up to 99.5%. According to the method, upgrading and recycling of the PET waste are achieved so as to cope with the threat of white pollution to the ecological environment and human health.

The invention relates to the technical field of recycling and reusing of solar back plates of photovoltaic modules, and discloses a recycling method of a solar back plate. The recovery method of the solar back panel is characterized by comprising the following steps: (1) in the presence of a protective gas and a catalyst, carrying out alcoholysis reaction on the solar back panel and alcohol to obtain a depolymerized mixed solution; and (2) carrying out purification treatment on the depolymerized mixed solution obtained in the step (1) to obtain bis (2-hydroxyethyl) terephthalate (BHET), polyvinylidene fluoride and polyolefin. According to the method, the PET middle layer in the solar panel can be completely depolymerized into the BHET monomer, the yield is greater than or equal to 78%, and the purity is greater than or equal to 98%; pVDF and PP (or PE) products can be respectively obtained after the PVDF and PP (or PE) materials which do not participate in depolymerization are separated and purified; the whole chemical recovery process is simple in operation method and high in efficiency, and has good economic benefits.

The invention provides an anthryl compound, a preparation method thereof and application of the anthryl compound as solar thermal fuel, and belongs to the field of energy and chemical industry. The anthryl compound can be converted into a dimer under the irradiation of 365nm ultraviolet light and store light energy as chemical energy at the same time, and is subjected to a photodepolymerization reaction under the irradiation of 254nm ultraviolet light and releases heat at the same time, that is, the anthryl solar thermal fuel can store or release photo-thermal energy through a reversible photodimerization / depolymerization reaction. In addition, the anthryl compound also has the unique advantage of light-operated reversible solid-liquid phase change, and the simultaneous storage of photon energy and phase change energy can be realized. The storage energy density of the anthryl compound is about 65 kJ / mol, and the storage half-life period is as long as 60 days. The anthryl compound and the preparation method thereof provided by the invention provide a new strategy for light energy storage and utilization.

The invention discloses an efficient purification method of rBHET, and belongs to the technical field of waste polyester recycling. A reaction raw material obtained after premixing of waste PET polyester raw material particles and a catalyst and ethylene glycol are jointly and continuously introduced into a depolymerization reactor, the reaction raw material and ethylene glycol in the depolymerization reactor are mixed and pass through a plurality of rotating discs, and the materials form a flowing film on the rotating discs rotating at a high speed to promote depolymerization; depolymerization reaction liquid generated in the depolymerization reactor enters a temporary storage tank to be stored after being subjected to impurity removal, the depolymerization reaction liquid in the storage tank is introduced into a rectifying tower to be primarily concentrated and purified, obtained concentrated liquid enters an evaporator to be secondarily concentrated and purified, obtained secondary concentrated liquid enters a cooler to be cooled and then enters a product tank to be crystallized; and drying the crystallized solid to obtain a high-purity rBHET product. According to the method, the production efficiency is improved, and the purity of rBHET is effectively improved.

The polyester resin according to the present invention is high purity and contains recycled bis(2-hydroxyethyl) terephthalate containing a controlled amount of diethylene glycol ester below a certain level, and therefore has heat resistance and quality comparable to that of the original resin, despite being a polyester resin regenerated by chemical recycling. In particular, the polyester fiber containing the polyester resin according to the present invention has excellent strength, elongation, and processability, and can therefore be used as an environmentally friendly textile product.

The invention discloses a high-purity BHET low-temperature continuous production process which comprises the following steps: (1) uniformly mixing waste PET powder and a catalyst, adding a solvent, stirring and mixing to form a muddy mixture, pumping the muddy mixture and ethylene glycol into a depolymerization kettle, and carrying out a depolymerization reaction to generate a BHET crude product; (2) the BHET crude product is continuously introduced into a hydrolysis kettle, water is continuously introduced, the BHET crude product is fully dissolved, the temperature in the hydrolysis kettle is 60-100 DEG C, and the pressure in the hydrolysis kettle is normal pressure; (3) filtering the fully dissolved BHET crude product, conveying a BHET liquid-phase product obtained by filtering into a purification tower, and carrying out purification treatment, so as to obtain a purified BHET liquid-phase product; and (4) cooling and crystallizing the purified BHET liquid-phase product, filtering and drying to obtain the high-purity BHET. According to the method, the alcoholysis reaction of PET and ethylene glycol is catalyzed by using the high-activity catalyst, the alcoholysis reaction temperature is reduced, the continuous production mode is more met, the produced BHET is purified, metal residues are reduced, and the purity of the BHET is further improved.

The recycled bis(4-hydroxybutyl) terephthalate according to one embodiment has a low amount of residual ethylene glycol derivatives and can therefore be used as a polymerization raw material for high crystallinity engineering polyester products or biodegradable polyesters, offering superior qualities, for example, color.

The present invention relates to a process for depolymerizing a material comprising polyethylene terephthalate (PET) by glycolysis with ethylene glycol (EG), comprising reacting the material comprising PET with EG in the presence of at least one catalyst so as to obtain a glycolized product containing bis (2- hydroxyethyl ) terephthalate (BHET) and / or oligomers thereof, wherein said catalyst comprises an acetate salt of a metal chosen from : calcium, magnesium, aluminium and mixtures thereof. The catalyst can be prepared in situ by a reaction between acetic acid and a compound containing the metal.

Process for purifying bis (2-hydroxyethyl) terephthalate (BHET) from a crude solution obtained by glycolysis of ethylene glycol (EG) from polyethylene terephthalate (PET) waste containing at least one dissolved barrier polymer, water being added to the crude solution in a predetermined amount as an anti-solvent for the barrier polymer, and controlling the temperature to ensure that the solubility of the barrier polymer is significantly reduced without causing precipitation of BHET and its oligomer. Specifically, water is added to the crude BHET solution in at least two different stages, the weight ratio between EG and H2O is reduced, and the temperature is also reduced. In this way, the barrier polymer can be more effectively removed, and precipitation of BHET and its oligomer is not caused. Furthermore, in this manner, the volume of the liquid to be treated can be maintained within a relatively small value, thereby avoiding equipment defects associated with the treatment of large quantities of liquid by decantation and / or filtration, which may cause the process to be inconvenient from the industrial perspective.

The present invention discloses a method for upgrading polyester materials to dicarboxylic acid esters and ethylene carbonate, and relates to the comprehensive utilization of waste resources and the cascade utilization of raw materials. The method uses multiple types of green ionic liquid catalysts to catalyze the methanolysis reaction of PET, and then dimethyl carbonate captures the generated ethylene glycol in situ, forms a five-membered cyclic ethylene carbonate through nucleophilic cyclization, pulls the reaction equilibrium to move forward, and completely depolymerizes PET waste. The products of the method of the present invention are dimethyl terephthalate and five-membered cyclic ethylene carbonate. The present invention can be used for the depolymerization and upgrading of waste PET materials, and can also be used for other similar polyesters, such as polyethylene succinate, polyethylene adipate and polyethylene 2,5-furan dicarboxylate, which are also suitable for the recovery strategy of the present invention, and the products are the corresponding dimethyl succinate, dimethyl adipate and 2,5-furan dicarboxylate.

The invention provides a method for alcoholysis of polyethylene glycol terephthalate, and relates to the technical field of PET degradation. The PET alcoholysis method provided by the invention comprises the following steps: mixing PET, ethylene glycol, a cosolvent and a composite catalyst, and carrying out alcoholysis reaction to obtain bis (hydroxyethyl) terephthalate (BHET). According to the invention, dimethyl sulfoxide is taken as a cosolvent, zinc acetate and 1, 8-diazabicyclo [5.4. 0] undec-7-ene are taken as a composite catalyst, catalysis and solvent effect driving are combined, and ethylene glycol alcoholysis of PET is carried out under the synergistic effect of the composite catalyst and the cosolvent. According to the method, effective decomposition of PET can be achieved at the low temperature (140-155 DEG C) and within the short reaction time (60-100 min), and the yield of BHET is high (66% or above and can reach 80% or above). The method provided by the invention can realize high-efficiency alcoholysis of PET with ethylene glycol.

The invention belongs to the technical field of PET (Polyethylene Terephthalate) recovery, and particularly relates to a method for efficiently recovering an impurity-containing polyester waste material under the assistance of a solvent. The method for efficiently recovering the impurity-containing polyester waste material with the assistance of the solvent comprises the following steps: S1, sequentially adding methanol, an auxiliary solvent and a catalyst into the waste impurity-containing PET material, performing alcoholysis with methanol, and filtering to obtain filter residues and first filtrate (alcoholysis products); s2, adding activated carbon into the first filtrate, stirring and filtering to obtain second filtrate; s3, performing rotary evaporation treatment on the second filtrate to obtain a rotary evaporation solid product; and S4, washing the rotary evaporation solid product with methanol, filtering to obtain DMT and a third filtrate, and carrying out two-stage reduced pressure distillation on the third filtrate to recover the catalyst, methanol and ethylene glycol. The method provided by the invention realizes recycling of the impurity-containing waste PET, reduces environmental pollution caused by PET polyester, saves petroleum resources, and promotes sustainable development of economy and resources.

The invention relates to the field of polyester, and discloses a method for continuously producing 1, 4-cyclohexanedimethanol by taking waste polyester as a raw material. Comprising the following steps: 1) mixing waste polyester with ethylene glycol, and performing alcoholysis under the action of an alcoholysis catalyst to obtain alcoholysis liquid containing diethylene glycol terephthalate; 2) performing primary hydrogenation on the alcoholysis solution under the catalysis of a hydrogenation catalyst A to obtain a reaction solution containing 1, 4-cyclohexane dioctyl phthalate diglycol ester; 3) performing secondary hydrogenation on the reaction liquid under the catalysis of a hydrogenation catalyst B to obtain a reaction liquid containing 1, 4-cyclohexanedimethanol; and 4) carrying out gas-liquid separation and rectification on the reaction liquid to obtain ethylene glycol and 1, 4-cyclohexanedimethanol. According to the method, the CHDM is produced by taking the waste polyester as the raw material, the method is simple in production process flow, and continuous production can be realized; through optimization of the catalyst and the process, high PET conversion rate, high CHDM selectivity, high CHDM yield and low production cost can be realized under relatively mild reaction conditions.

The invention discloses a process for preparing DMT and DOTP by recycling waste printing and dyeing white mud. The process comprises a pretreatment unit, a methyl esterification unit, a rectification unit, a pulping unit, an ester exchange unit and a refining unit, waste printing and dyeing white mud is used for methyl esterification to prepare DMT, DMT rectification and purification, DMT transesterification to prepare DOTP and DOTP purification. According to the process, efficient esterification of the white mud and product separation can be achieved through the catalyst and the process conditions adopted in the methyl esterification stage, the obtained refined DMT can serve as a polyester monomer product and can also serve as a raw material to further react with isooctanol to prepare DOTP, and high-valued conversion and resource utilization of the white mud are achieved through the process.

The invention discloses a method for efficiently depolymerizing polyethylene glycol terephthalate, which comprises the following steps: mixing a PET material, ethylene glycol and a core-shell type magnetic nano composite catalyst, and carrying out alcoholysis reaction at 160-200 DEG C for 30-180 minutes; after the reaction is finished, separating the catalyst from a reaction system through an external magnetic field to obtain a solution containing bis (2-hydroxyethyl) terephthalate; the core-shell type magnetic nano composite catalyst comprises a magnetic FeO core, a SiO shell layer and active metal sites, the FeO core is coated with the SiO shell layer, the SiO shell layer is an insulating inorganic layer and is of a porous structure, the active metal sites are fixed to the surface of the SiO shell layer through coordinate bonds, and active metal is selected from one or more of Co, Ni, Cu, Ce, La and Al. The problems that an existing PET alcoholysis catalyst is easy to dissolve out, difficult to separate, harsh in reaction condition and poor in cycling stability are solved.

The invention belongs to the technical field of copolymerization modification of degradable polyester, and relates to a depolymerization method and application of polybutylene terephthalate. During depolymerization, polybutylene terephthalate, dimethyl carbonate and dihydric alcohol are mixed and then subjected to a depolymerization reaction, and an intermediate ester is prepared; the dihydric alcohol is dihydric alcohol which does not form a ring with dimethyl carbonate in the depolymerization reaction process; the molar weight of the dimethyl carbonate is 10-30% of the molar weight of a repetitive unit of the polybutylene terephthalate; the sum of the molar weight of a 1, 4-butanediol unit in the polybutylene terephthalate and the molar weight of the added dihydric alcohol is a, the sum of the molar weight of a terephthalic acid unit in the polybutylene terephthalate and the molar weight of the added dimethyl carbonate is b, and the ratio of b to a is (1.2-1.5): 1; during application, the prepared intermediate ester is subjected to transesterification under the condition of negative pressure to obtain the copolyester. The depolymerization method is simple and easy to implement; the depolymerization product can be directly applied.

A polymerization raw material obtained by the depolymerization of waste polyester is disclosed. The polymerization raw material contains recycled bis(2-hydroxyethyl) terephthalate in which the contents of acetate-based ester compounds and diethylene glycol ester compounds are adjusted to specific levels. The polymerization raw material is excellent in purity and quality, and free from the problem that thermal resistance characteristics deteriorate in the polymerization of a polymer from the recycled monomer.

The invention relates to the technical field of recycling of waste textiles, in particular to a method for accelerating degradation of waste polyester, which comprises the following steps: S1, adding crushed polyester materials into organic alcohol, and then adding organic alkali and a photodegradation catalyst to obtain a degradation system; and S2, carrying out a degradation reaction in the degradation system under illumination and heating conditions, and after the reaction is finished, carrying out constant-temperature solid-liquid separation, cooling crystallization, washing and drying to obtain the terephthalic acid glycol ester. The photodegradation catalyst is at least one of nano ZnO and nano TiO2. According to the method disclosed by the invention, low-temperature and rapid degradation can be realized to obtain the terephthalic acid glycol ester, the energy consumption of polyester degradation is effectively reduced, the yield of polyester recovery is improved, and the recycling of polyester fabrics is realized.

The application belongs to the technical field of regenerated polyester, and particularly relates to a recycling method of waste polyester textiles, which comprises the following steps: decolorizing colored waste polyester textiles by using a decolorizing agent, wherein the decolorizing agent is one or more of dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; depolymerizing the decolorized polyester textiles by using a depolymerizing agent to obtain terephthalate, wherein the depolymerization rate of the decolorized polyester textiles is 98.0-100%; converting the terephthalate into DMT first, and then performing a re-polymerization reaction on the DMT, ethylene glycol, a catalyst and a functional additive to obtain regenerated PET. The application adopts a process of decolorizing first and then depolymerizing, and the decolorizing and depolymerizing are coordinated, so that the process is simplified, the energy consumption and pollution are reduced, and the economy and sustainability of the recycling of waste polyester textiles are improved.