51results about "Preparation by transesterification" patented technology

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.

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.

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 invention discloses a method for catalyzing polyester depolymerization by halogen salt substances. The method comprises the following step: carrying out chemical depolymerization reaction on polyester or a polyester-containing composite material in diester carbonate under the condition of taking a halogen salt substance as a catalyst. The method has the advantages of high efficiency, greenness, mild reaction conditions and the like, polyester can be depolymerized to generate the polyester monomer, a new method is provided for chemical conversion of waste polyester plastic, and the method has high industrial application value.

The present invention primarily relates to a method for producing a compound of formula (I) and / or a physiologically acceptable salt thereof from vanillylmandelic acid and / or a physiologically acceptable salt thereof. The present invention further relates to the simultaneous use of one or more iodide salt(s) or hydrate(s) thereof, one or more reducing agent(s), one or more inorganic and / or organic acid(s) other than phosphonic acid, and methanol and / or a physiologically acceptable salt thereof or an alcohol of formula (II) as defined herein and / or a physiologically acceptable salt thereof for converting vanillylmandelic acid and / or a physiologically acceptable salt thereof into a compound of formula (I) and / or a physiologically acceptable salt thereof or into a compound of formula (III) as defined herein and / or a physiologically acceptable salt thereof.

A recycled bis(4-hydroxybutyl)terephthalate according to an embodiment has a low residual amount of ethylene glycol derivatives, and thus, can be used as a polymerization raw material for high-crystallinity engineering polyester products or biodegradable polyester, and provides excellent quality of, for example, color.

The present invention describes the preparation of heterogeneous catalysts of mixed oxides based upon niobium and mixed oxides of zinc, manganese, nickel, cobalt and / or aluminum, originating from hydrotalcites (HTs) as precursor phase of heterogeneous catalysts, and application thereof in the chemical recycling of poly(ethylene terephthalate) (PET) for the production of metal free bis(hydroxy)ethylene (BHET) monomers and oligomers having a processing performance similar to that of the homogeneous catalysis system.

According to the present invention, bis(glycol)terephthalate can be prepared by a transesterification reaction of glycol and bis(2-hydroxyethyl)terephthalate and then introduced to a polymerization reaction to increase the content of recycled raw materials in a polyester resin. In addition, purity is improved through the removal of impurities by extracting glycol byproducts during the transesterification reaction, and thus the quality of the final resin can be improved while reducing the amount of byproducts from the polymerization reaction.

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 invention discloses a method for catalyzing depolymerization of polyethylene glycol terephthalate (PET) by halogen anion inorganic salt. Under the condition that inorganic metal salt of halogen anions serves as a catalyst, PET or a composite system of PET is treated in diester carbonate, chemical depolymerization of PET is achieved, PET monomers of diester terephthalate and ethylene carbonate are obtained, and complete depolymerization of PET in a composite body is achieved. According to the method disclosed by the invention, through the reaction of the diester carbonate and the PET, the depolymerization of the PET under a mild condition can be realized, and the related technology research and development of chemical recovery of the PET monomer in a PET composite system or a mixed system are further carried out. The method provided by the invention has the advantages of high efficiency, greenness, mild reaction conditions and the like, can catalyze PET depolymerization to generate the monomer terephthalic acid diester, and has higher industrial application value.

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.

This invention provides a degradation process for composite polyester materials, relating to the field of polyester recycling technology. The degradation process involves depolymerizing a reaction system comprising at least raw material components (i) composite polyester material, (ii) organic ester compounds, (iii) a co-solvent, and (iv) an alkaline catalyst at a temperature not exceeding 100°C; the weight ratio of the co-solvent to the organic ester compound is ≥0.5. By adding a certain amount of co-solvent to the depolymerization system, this invention achieves directional depolymerization of polyester-containing composite polyester materials while essentially preventing depolymerization of other materials, such as spandex and nylon.

The application provides a process and system for recovering DMT and DMC from polyester-containing blended fabric, comprising: under the action of an ionic catalyst, a depolymerization reaction of polyester-containing blended fabric and DMC; after the reaction, the material is subjected to solid-liquid separation and first crystallization to obtain a crystallization mother liquor and a DMT crude product, the DMT crude product is subjected to dissolution, removal of solid impurities and recrystallization to obtain a DMT pure product; the crystallization mother liquor is subjected to light removal, reaction rectification and extractive rectification to obtain a second DMC fraction, which is recycled to the depolymerization reaction; a methanol fraction, which is recycled to the reaction rectification; and an extractant fraction, which is recycled to the extractive rectification. The operation conditions are mild, the material and energy are closely coupled between units, a multiple circulation network of DMC, methanol, extractant and catalyst is formed, the overall resource utilization rate is high, the degree of greenness is high, and an economic and feasible technical scheme which is easy to industrialize is provided for chemical recycling of waste polyester textiles.

Processes for recovering dialkyl terephthalates. The processes can include exposing a feedstock composition that includes one or more tetramethylcyclobutanediol (TMCD)-containing polyesters ethylene glycol, methanol, or both under 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.

Processes for recovering dialkyl terephthalates. The processes can include exposing a polyester composition to a first composition including one or more glycols and methanol under 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 and / or methanol can be recovered at the end of the alcoholysis process and re-used in subsequent processes for recovering dialkyl terephthalates.

The present invention relates to the field of recycling materials containing polyester terephthalate, particularly polyethylene terephthalate (PET), polybutylene terephthalate (PBT), or polytrimethylene terephthalate (PTT), commonly used in the manufacture of disposable plastic bottles, food trays, textiles, and composite insulation materials. It specifically concerns a process for recycling PET into terephthalic diester, and in particular dimethyl terephthalate (DMT), in less than one hour and without any pretreatment steps. Furthermore, this process uses products with a low environmental impact. It is therefore particularly advantageous from an industrial perspective.

To provide novel fatty acid esters. [Solution] A fatty acid ester is used, which contains 3% by mass or less of a lactone with 18 carbon atoms and has an acid value of 1 mgKOH / g or less.

The invention discloses a method for catalyzing polyester depolymerization by alkoxide. The method comprises the following steps: carrying out chemical depolymerization reaction on polyester or a polyester-containing composite material in diester carbonate in the absence of a catalyst or in the presence of an organic salt as a catalyst, wherein the organic salt comprises metal organic salt and organic anion ionic liquid; anions in the metal organic salt and the organic anion ionic liquid are independently selected from the following anions: alcohol anions, phenol anions, mercaptan anions and thiophenol anions. The method has the advantages of high efficiency, greenness, mild reaction conditions and the like, polyester can be depolymerized to generate the polyester monomer, a new method is provided for chemical conversion of waste polyester plastic, and the method has high industrial application value.

The invention discloses a method for depolymerizing polyurethane based on diester carbonate under catalysis of halogen salt substances. The polyurethane depolymerization method comprises the following step: carrying out chemical depolymerization on polyurethane or a polyurethane-containing composite material in diester carbonate in the absence of a catalyst or under the condition that a halogen salt substance is used as a catalyst. By adopting the method, the depolymerization of the polyurethane under mild conditions can be realized, and the polyurethane is converted into valuable chemicals such as carbamate derivatives and polyhydric alcohols. Most of the used catalysts are halogen salts which are cheap and easy to obtain, so that the cost is lower, and the catalysts can be recycled. The method provides a new way for resource utilization of the polyurethane waste, and accords with the development direction of green chemistry and circular economy.

This invention provides a degradation process for PET polyester, relating to the field of polyester recycling technology. The degradation process involves depolymerizing a reaction system containing PET polyester material, a depolymerizing agent, and an alkaline catalyst at a degradation temperature not exceeding 100°C; the depolymerizing agent is selected from organic ester compounds. This invention uses organic ester compounds as both the degradation agent and alkylating agent for PET polyester degradation, resulting in mild reaction conditions that allow for relatively complete degradation of the PET polyester material and yield of high-yield dialkyl terephthalate.

Disclosed in the present invention is a method for preparing a terephthalate diester by catalyzing the depolymerization of polyethylene terephthalate (PET). Treating PET or a composite system thereof in a carbonate diester without a catalyst or under the condition of using a salt substance as a catalyst realizes chemical depolymerization of the PET, thereby obtaining the PET monomer terephthalate diester and ethylene carbonate and realizing complete depolymerization of the PET in the composite. The present invention can realize the depolymerization of PET under mild conditions by means of the reaction between the carbonate diester and the PET, and further carry out the research and development of related technology for the chemical recovery of the PET monomer from a PET composite system or a PET mixed system. The method provided by the present invention has the advantages of high efficiency, greenness, mild reaction conditions, etc., can catalyze the depolymerization of PET to generate the monomer terephthalate diester, and has a relatively strong industrial application value.

The present invention relates to the manufacture of alkyl (meth)acrylate by catalyzed transesterification. More specifically, it relates to an improved process for the manufacture of alkyl (meth)acrylate, leading to high productivity of a product meeting purity standards, and comprising a step of valorizing the heavy by-products generated during this manufacture by means of a thermal and catalytic cracking step, generating reagents recycled in the process as well as methane and mineral salts obtained by hydrothermal gasification of this cracking residue alone, in mixture with residues of other alkyl esters or with alcohols.

The invention discloses a method for depolymerizing polyethylene glycol terephthalate (PET) under a catalyst-free condition. Under the condition of no catalyst, PET or a composite system thereof is treated in diester carbonate, chemical depolymerization of PET is realized, PET monomers of diester terephthalate and ethylene carbonate are obtained, and complete depolymerization of PET in a composite is realized. According to the method disclosed by the invention, through the reaction of the diester carbonate and the PET, the depolymerization of the PET under a mild condition can be realized, and the related technology research and development of chemical recovery of the PET monomer in a PET composite system or a mixed system are further carried out. The method provided by the invention has the advantages of high efficiency, greenness, mild reaction conditions and the like, can catalyze PET depolymerization to generate the monomer terephthalic acid diester, and has higher industrial application value.

The present invention relates to a process for the preparation of a polyester having repeating units [−A''−B''] of formula [−O−R 1 −OOC−R 2 −CO−], comprising the following steps: heating a recovered monomer product obtained from depolymerization of a polyester together with 3-50% by weight of water to a temperature higher than the melting point of said condensation monomers in a reactor at a pressure higher than ambient pressure by at least 0.5 bar to obtain a modified recovered monomer product having an increased concentration of COOH end groups. The present invention also relates to the use of a polyester prepared from said modified recovered monomer product for a solid state polycondensation reaction.

The present disclosure provides processes for preparing an alpha-hydroxy ester from the corresponding alpha-hydroxy acid by transesterification. Also provided are alpha-hydroxy esters prepared according to processes disclosed herein and compositions comprising the alpha-hydroxy esters.

The present invention relates to a method for preparing recycled feedstock using waste copolyester, the method for preparing recycled feedstock includes the steps of: (1) depolymerizing waste copolyester to obtain a first reactant; (2) removing impurities present in the first reactant to obtain a second reactant; (3) distilling the second reactant to obtain a third reactant containing crude recycled bis-2-hydroxyethyl terephthalate and a fourth reactant containing recycled diol-ester; and (4) mixing the third reactant with an aqueous solvent and recrystallizing it to obtain a fifth reactant containing recycled bis-2-hydroxyethyl terephthalate and a filtrate.