393results about "Preparation by ester-hydroxy reaction" patented technology

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 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.

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 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.

The present invention relates to a process for depolymerizing a polyester feedstock comprising opaque PET, which comprises: a) a conditioning step; b) a step of glycolysis, operated at between 180 and 400° C., a residence time of from 0.1 to 10 h in the presence of diol; c) a diol separation step, at a temperature of between 100 and 250° C., a pressure lower than that of step b) and producing a diol effluent and an effluent rich in monomers; d) a step of separating into a heavy impurities effluent and a prepurified monomers effluent, at a temperature of less than 250° C. and a pressure of less than 0.001 MPa and a residence time of less than 10 min; e) a step of decolourizing the prepurified monomers effluent, by adsorption of a mixture comprising between 20% and 90% by weight of the prepurified monomers effluent and a solvent, at a temperature of between 100 and 200° C., a pressure of between 0.1 and 1.0 MPa and in the presence of at least one adsorbent.

The invention relates to the field of functional materials, in particular to chemical recycling of a series of polyesters represented by PET (Polyethylene Terephthalate) by using a novel and efficient magnesium-based catalyst technology, which is of great significance for treating plastic pollution and realizing green circular economy.

The present invention relates to a method for alcoholysis of a plastic, in which the plastic is subjected to an alcoholysis reaction using a specific binuclear metal complex catalyst in the presence of an alcoholysis agent to obtain a monomer, and the plastic is one or more selected from the group consisting of polyester, polycarbonate, polyamide and polyurethane. According to the alcoholysis method of the plastic, catalytic alcoholysis can be efficiently carried out, the purity of a monomer product is high, post-treatment is simple, and various plastics can be treated.

The invention discloses a method for recovering monohydroxyethyl terephthalate from a polyester textile, which comprises the following steps: carrying out multi-stage decolorizing treatment on the polyester textile to be recovered by using ethylene glycol as a decolorizing agent to obtain the decolorized polyester textile; mixing a depolymerization catalyst, a sodium phosphate buffer solution and the decolored polyester textile, and carrying out a depolymerization reaction to obtain a depolymerization solution; adding ethyl acetate into the depolymerization liquid for extraction, rotary evaporation concentration and sublimation treatment to obtain monohydroxyethyl terephthalate. According to the method for recycling the monohydroxyethyl terephthalate from the polyester textile, the decolorization rate of the polyester textile can reach 90% or above, the purity of the recycled monohydroxyethyl terephthalate is larger than 98%, and the whiteness of the recycled monohydroxyethyl terephthalate is larger than 97%. The method for recycling the monohydroxyethyl terephthalate from the polyester textile, provided by the invention, is an efficient, economical and green new method for recycling the polyester, and the recycling of the polyester textile is realized.

Provided are a preparation method of an ion catalyst material for PET chemical recycling and a PET chemical recycling method. The preparation method of an ion catalyst material for PET chemical recycling includes the following. A metal chloride is added to an alkylimidazole-chloride ionic liquid to form a bisalkylimidazole-metal tetrachloride ionic liquid that is grafted on a porous carrier.

The invention discloses a method for synthesizing dialkyl terephthalate through waste PET plastic alcoholysis based on a VTa-coated NC / C catalyst, the conversion rate of PET plastic is 100%, the yield of dimethyl terephthalate and ethylene glycol is as high as 99%, no obvious inactivation phenomenon exists after the catalyst is used for 10 times, and the method is suitable for industrial production. The catalytic system is also effective to n-butyl alcohol, 2-ethylhexanol, isononyl alcohol, isodecyl alcohol and ethylene glycol, a series of plastic additives and ethylene glycol can be obtained, and the product yield is 89% or above.

The invention relates to the technical field of high-valued utilization of solid wastes, and discloses a transition metal doped iron-containing solid waste catalytic material, a preparation method thereof and an application of the transition metal doped iron-containing solid waste catalytic material in degradation of PET (Polyethylene Terephthalate). The method comprises the following steps: carrying out physical screening or disc (ball) milling treatment on the iron-containing solid waste, then dissolving the iron-containing solid waste in organic acid, and heating and stirring to obtain turbid liquid; carrying out solid-liquid separation on the turbid liquid to obtain a solid; dissolving transition metal salt in water, adding the transition metal salt and the solid into a reaction container, adding oxalic acid, adjusting the pH value, and uniformly stirring and mixing; carrying out heating reaction on the mixed solution, and drying an obtained reaction product to obtain a precursor; and roasting the precursor to obtain the transition metal doped ferrite catalyst. The method for preparing the PET alcoholysis efficient catalyst from the iron-containing solid waste has the advantages of being low in raw material cost, high in catalytic efficiency, low in equipment requirement, easy to separate and recycle and the like, a brand new thought is provided for PET alcoholysis, the method has a large application prospect, and the catalytic material is suitable for industrialization.

The invention relates to the technical field of high polymer material recovery, in particular to a composite catalyst for preparing DMT through PET alcoholysis and a preparation method and application of the composite catalyst. The composite catalyst comprises a solid acid material which is obtained by carrying out proton transfer reaction on silica gel of which the surface is grafted with aluminum alkyl and perfluoroalkyl sulfonic acid of which the general formula is Rf-SO3H, wherein Rf is a perfluoroalkyl group with the carbon atom number of 1-10. Through the synergistic effect of the components, the composite catalyst shows excellent performance in the process of degrading PET (Polyethylene Terephthalate) by monohydric alcohol. When methanol is used as an alcoholysis agent, the yield of the main product dimethyl terephthalate (DMT) can reach 95% or above, the catalytic efficiency is high, the stability is good, an efficient catalyst is provided for industrialization of chemical recovery of PET, and the method has important economic and environmental values.

The invention relates to a reaction process for recovering BHET by depolymerizing PET, belonging to the technical field of high polymer material recovery. The process comprises the following steps: mixing a raw material containing waste PET particles and ethylene glycol with a sylvite catalyst, placing the mixture in a closed container, carrying out a depolymerization reaction in an inactive atmosphere to obtain a depolymerization solution, mixing the depolymerization solution with methanol and BHET seed crystals, carrying out an ester exchange reaction to obtain a reaction solution, cooling the reaction solution to 25 DEG C at a speed of 10 DEG C / min, crystallizing for 3-6 hours, carrying out acid pickling, and drying to obtain the PET / BHET composite material. A BHET crystal is obtained; pressure oscillation is intermittently carried out in the depolymerization reaction process. The low-temperature depolymerization rate is increased by adopting the potassium salt catalyst, and meanwhile, directional migration of impurities is induced through periodic pressure change, so that full-continuous operation is realized.

The invention discloses a surface zinc-loaded molecular sieve catalyst for PET (polyethylene terephthalate) depolymerization and a preparation method of the surface zinc-loaded molecular sieve catalyst. According to the catalyst, a molecular sieve with a framework silica-alumina ratio of 25-400 is adopted as a carrier, and zinc species are strongly loaded on the outer surface of the molecular sieve through chemical bonding. The preparation method comprises the following steps: dissolving a zinc source in water, and adjusting to a specific pH value by using inorganic acid to obtain a zinc-containing solution; dipping a molecular sieve carrier in the solution under a heating condition; and finally, filtering, washing, drying and roasting to obtain a finished product. The catalyst successfully solves the problem that reaction activity and separability of a traditional solid catalyst in PET glycol alcoholysis are difficult to consider at the same time by accurately regulating and controlling active site distribution, shows high activity and excellent cycling stability close to those of a homogeneous catalyst, and has remarkable industrial application potential.

This invention discloses a method for preparing high-quality bio-based 1,9-nonanediol, comprising the following steps: transesterification, precipitation, fatty acid methyl ester refining, ozone oxidation pyrolysis, solvent recovery, esterification, dimethyl azelaate refining, and hydrogenation to obtain high-quality bio-based 1,9-nonanediol. This invention achieves gradient and full-component utilization of vegetable oil raw materials: the oil-based portion of triglycerides is used to produce high-quality bio-based 1,9-nonanediol, while simultaneously producing byproducts such as methyl palmitate, methyl stearate, propionic acid, hexanoic acid, and nonanoic acid; the glycerol-based portion of triglycerides is used as a byproduct of glycerol production. This invention utilizes esterification to reconstruct the products of ozone oxidation pyrolysis, converting the high-boiling-point monomethyl azelaate into the low-boiling-point dimethyl azelaate, achieving efficient separation from saturated fatty acid methyl esters. The dimethyl azelaate, as a raw material, is then hydrogenated to obtain high-quality nonanediol, significantly reducing production costs.

The present disclosure relates to a process for the depolymerization of polyethylene terephthalate (PET). The process of the present disclosure is performed without using any catalyst or ionic liquids. Further, the reagents used in the process can be recovered and reused.

The invention relates to an electrochemical process for the preparation of 1,2,3,4-butanetetracarboxylic acid tetraalkyl esters containing alkyl groups having 1 to 6 carbon atoms. The process comprises the electrohydrodimerization of dialkyl maleates containing alkyl groups having 1 to 6 carbon atoms in a reactant solution containing an alcohol and a conductive salt.

Through a transesterification reaction in which a predetermined amount of bis(2-hydroxyethyl)terephthalate relative to glycol is fed in a divided or continuous manner, bis(glycol)terephthalate with a low residual amount of an ethylene glycol derivative is prepared, and polyester engineering products or biodegradable polyester products with high crystallinity can be produced therefrom.

This invention discloses a method for preparing ethylhexyl palmitate, relating to the technical field of ethylhexyl palmitate. First, isooctanol is vaporized and passed into a methyl palmitate solution to prepare ethylhexyl palmitate via transesterification. The gaseous feed increases the instantaneous concentration of alcohol in the liquid phase, promoting the reaction in the forward direction and increasing the reaction rate. Simultaneously, methanol generated by the transesterification process is also vaporized and carried out of the system, further promoting the forward reaction and making it more complete. Second, a catalyst is synthesized using a chromium salt as a metal source precursor and a 2-sulfonyl-4,4'-biphenyldicarboxylic acid ligand. The biphenyl groups in the ligand provide rigid and hydrophobic large pores, providing a locally high-concentration reaction environment. Gaseous isooctanol can easily diffuse into the catalyst pores, contacting the enriched methyl palmitate. Furthermore, the uniformly distributed sulfonic acid groups in the ligand, acting as a solid superacid, provide strong acidic sites, improving production efficiency.

The invention discloses a polyol gradient synergetic depolymerization-esterification coupling reaction device for PETG chemical recovery, and belongs to the technical field of depolymerization-esterification coupling reaction devices, the polyol gradient synergetic depolymerization-esterification coupling reaction device comprises a main reaction kettle, the main reaction kettle is of a vertical cylindrical structure, the top of the main reaction kettle is fixedly connected with a sealing cover, the sealing cover is connected with a plurality of feeding ports, and the feeding ports are communicated with the main reaction kettle. A liquid collecting cavity is connected below the main reaction kettle, a return pipe is connected to the bottom of the liquid collecting cavity, a one-way valve is arranged on the return pipe, a multi-stage alcohol feeding system is arranged on one side of the main reaction kettle, a gradient temperature control jacket assembly is arranged on the other side of the main reaction kettle, and an in-situ esterification module is arranged on the inner side of the main reaction kettle. According to the method, multiple alcohol reagents are introduced according to the gradient synergistic effect, the breaking requirements of different types of ester bonds in PETG molecules are accurately matched, the depolymerization and esterification processes are coupled in situ, efficient, low-consumption and high-valued closed-loop recovery is achieved, and the defects that depolymerization is not thorough, products are complex, the technology is tedious and the like when PETG is treated in the prior art are effectively overcome.

The application discloses a method for alcoholysis of waste PET polyester, which comprises the following steps: dissolving waste PET polyester in ethylene glycol, contacting with a catalyst, and reacting to obtain bis(hydroxyethyl) terephthalate; the waste PET polyester is at least one selected from waste PET packaging bottles, waste PET films and PET fiber waste; the catalyst is composed of a metal oxide carrier and active metal oxides loaded on the surface of the metal oxide carrier; the metal oxide carrier is at least one selected from ZnO, gamma-Al2O3, Fe3O4, SiO2, TiO2, CeO2 and MgO; the active metal oxides are at least one selected from MnO2, Co2O3, CeO2, PbO, CuO, NiO and SnO2; the mass of the active metal oxides is 5-60 wt% of the mass of the catalyst, wherein the mass of the active metal oxides is the mass of metal elements contained therein.

The disclosed recycling method of waste polyester depolymerization and mild selective depolymerization of blended textiles is to use waste polyester and blended textiles as raw materials, under the action of alkaline catalyst, or use mixed solvents composed of alcohol compounds and aprotic solvents as reaction solvents, or use alcohol compounds or mixed solvents composed of alcohol compounds and aprotic solvents as reaction solvents, so that the polyester in waste polyester and blended textiles undergoes hydrolysis, selective hydrolysis, alcoholysis or selective alcoholysis, and then depolymerizes to generate small molecule degradation products, while other non-polyester components do not undergo chemical changes. The alkaline catalyst and reaction solvent selected by the application not only can reduce the reaction temperature, but also can efficiently catalyze the depolymerization of polyester without causing chemical changes in non-polyester components, so that the energy consumption and reaction time can be greatly reduced, the recycling efficiency can be improved, the purity and yield of polyester depolymerization products can be greatly improved, and the recycling and utilization of all components in textiles can be realized.

The invention relates to a preparation method of 3-ethoxy isoamyl propionate, and belongs to the technical field of organic solvent synthesis. The preparation method of the 3-ethoxy isoamyl propionate comprises the following steps: S1, adding ethanol, a polymerization inhibitor and a catalyst A into a reaction kettle, heating to 40-55 DEG C, then dropwise adding ethyl acrylate, preserving heat, and carrying out addition reaction for 1-3 hours to obtain a reaction mixture; s2, adding an acidic material for neutralization, and carrying out vacuum rectification to obtain ethyl 3-ethoxypropionate; s3, adding ethyl 3-ethoxypropionate and a catalyst B into a reaction kettle, heating to 100-120 DEG C, introducing isoamyl alcohol, controlling the reaction temperature to 100-115 DEG C, and carrying out transesterification for 2.5-4 hours to obtain a crude product; and S4, cooling to stop the reaction, separating to remove the catalyst B, and carrying out reduced pressure rectification on the obtained crude product to obtain the 3-ethoxypropionic acid isoamyl ester. The method has the effects of mild process, high conversion rate and high product yield.

The invention relates to the technical field of waste polyester recycling and reusing, and discloses a method for depolymerizing copolyester, a depolymerization product and application of the depolymerization product in preparation of the copolyester. The preparation method comprises the following steps: carrying out a depolymerization reaction on copolyester with an average particle size of 0.1-5 cm to obtain a depolymerization solution containing bis (2-hydroxyethyl) terephthalate, a bis (2-hydroxyethyl) terephthalate dimer and cyclohexanedimethanol terephthalate; wherein the copolyester is polyethylene glycol terephthalate-1, 4-cyclohexanedimethanol ester, the water content in the copolyester is less than or equal to 2wt%, and the catalyst is a titanium-containing catalyst. According to the method disclosed by the invention, chemical depolymerization of PETG (or PCTG) copolyester can be realized, the depolymerization rate of the copolyester is improved, and a recyclable polymeric monomer is obtained.

The invention provides a preparation method of methacrylic acid 2-butoxyethyl ester, and belongs to the technical field of organic synthesis. According to the invention, p-hydroxyanisole (MEHQ) and 2, 2, 6, 6-tetramethylpiperidine oxide (TEMPO) are used as polymerization inhibitors at the same time, and the dual polymerization inhibitors are synergistically used, so that the auto-polymerization of methyl methacrylate (MMA) and 2-butoxyethyl methacrylate is reduced, and the conversion rate is increased.

The present disclosure relates to a depolymerization method of a polymer comprising an ester functional group with or without pigments or dyes, a composition for the depolymerization, and a purification method for selectively separating foreign substances from a monomer of the polymer, and is characterized in that a compound represented by formula 1 is added as an additive. The depolymerization method according to the present disclosure enables depolymerization at low temperatures and may increase the yield of a target product. In addition, the purification method according to the present disclosure may remove foreign substances including pigments or dyes from a monomer of the polymer to prepare high-purity monomers.

The application discloses a method for recycling polyester fabric by using an ionic liquid catalyst, and comprises the following steps: providing a recycled polyester fabric; chemically depolymerizing the recycled polyester fabric by using a chemical depolymerization solution to form a depolymerization product containing bis-hydroxyethyl terephthalate (BHET), wherein the chemical depolymerization solution is used to chemically depolymerize the recycled polyester fabric in the presence of a depolymerization catalyst, and the depolymerization catalyst is an ionic liquid catalyst. The method has the advantages of high depolymerization efficiency, high BHET yield and easy recovery of the catalyst.

The invention relates to a multi-metal zinc complex, a preparation method and application in polymer depolymerization. The multi-metal zinc complex forms a stable coordinate bond with an organic ligand molecular skeleton, shows excellent chemical stability and substrate adaptability, and can efficiently catalyze the depolymerization reaction of various polymers in a temperature range of 100-250 DEG C. In addition, the ligand framework has adjustability, polymer substrates with different compositions and structures can be optimized, and high-yield recovery of various types of monomers is realized. The catalytic system has wide applicability, can catalyze the bulk depolymerization of the polymer, and also can catalyze the depolymerization in the presence of a nucleophilic reagent. Through a multi-metal concerted catalysis mechanism, the dosage of the catalyst is remarkably reduced, various polymers with the number-average molecular weight in the range of 3.8-807.5 kg / mol can be depolymerized, the depolymerization reaction time is 0.5-24.0 h, side reactions are remarkably inhibited, and excellent industrial application prospects are shown.

The invention pertains to a method for mixed fabric fiber rejuvenation, wherein the method comprises the steps of adding ethylene glycol (EG) in gas phase at a temperature of between 190° to 250° C trough vapour injection to a fabric fibre material comprising polyester and natural fibre material, whereby at least partly depolymerising the polyester material to monomeric and oligomeric polyester residues, the monomeric and oligomeric polyester residues being dissolved in condensed, excess of liquid EG; optionally adding liquid phase EG, recovering a solvent phase, comprising the monomeric and oligomeric polyester residues and unreacted EG, and an essentially polyester-free natural fibre as a solid product; and optionally separating the solvent phase, comprising the monomeric and oligomeric polyester residues and unreacted EG, from the solid product, comprising essentially polyester-free natural fibre. Further is provided a system 100 for mixed fabric fiber rejuvenation of a mixed fabric fibre material comprising polyester and natural fibre material.

The present invention relates to a plasticizer composition, which comprises 2-ethylhexyl (2-hydroxyethyl) terephthalate, di(2-ethylhexyl) isophthalate, and di(2-ethylhexyl) terephthalate, and is characterized in that the content of the 2-ethylhexyl (2-hydroxyethyl) terephthalate is 20% by weight or less based on the total weight of the plasticizer composition. The plasticizer composition can improve mechanical properties, migration resistance, and heat loss properties when applied to a resin.