77results about "Preparation by transesterification" patented technology

This invention discloses a method for catalytically depolymerizing polyethylene terephthalate (PET) to prepare terephthalate. Under catalyst-free conditions or with a salt as a catalyst, PET or its composite system is treated in diester carbonate to achieve chemical depolymerization of PET, yielding PET monomers terephthalate and ethylene carbonate, and achieving complete depolymerization of PET in the composite. This invention, through the reaction of diester carbonate with PET, enables the depolymerization of PET under mild conditions, and further facilitates the research and development of related technologies for the chemical recovery of PET monomers from PET composite or mixed systems. The method provided by this invention has advantages such as high efficiency, environmental friendliness, and mild reaction conditions, and can catalyze the depolymerization of PET to generate its monomer terephthalate, possessing strong industrial application value.

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.

Disclosed is a process for preparing a hydroxyphenyl carboxylic acid ester, the process comprising a catalytic transesterification step using an alkali metal carbonate or alkali metal bicarbonate as a catalyst. Disclosed is a transesterification process in which (a) a substituted phenol comprising a carboxylic acid methoxy ester moiety linked to the phenol ring directly or indirectly via an alkyl chain CmH2m and a fatty alcohol are charged into a container, (b) a mixture of the two components is heated above the melting points of the two components and a vacuum is applied, and an alkali metal carbonate or an alkali metal bicarbonate is already present in step (b) or added to the liquid mixture in step (c), and a transesterification reaction takes place. The use of alkali metal carbonate or bicarbonate as a catalyst results in a safe, sustainable, environmentally friendly process that avoids toxic by-products and does not require large conditioning.

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 present invention provides a method for recycling polyethylene terephthalate (PET), the method comprising: (i) subjecting the PET to base-catalysed transesterification with a C6-C10 mono-alcohol to produce a composition comprising one or both of a mono-ester and di-ester terephthalate C6-C10mono-alcohol derivatives; and (ii) converting the so formed one or both of mono-ester and di-ester terephthalate C6-C10mono-alcohol derivatives into terephthalic acid using an esterase.

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.

To provide a membrane reactor capable of improving yield of a target product by progressing efficiently a catalyst reaction, in a reaction controlled by chemical equilibrium.SOLUTION: Concerning a membrane reactor for performing a reaction controlled by chemical equilibrium, the membrane reactor has a separation membrane for selectively and continuously separating, from reaction liquid, a by-product generated by the reaction. By selectively and continuously separating the by-product from the reaction liquid, the chemical equilibrium is shifted and the reaction is furthermore progressed.SELECTED DRAWING: None

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.

The disclosure generally relates to a method for hydrolyzing a terephthalic acid monoester, the method comprising exposing the terephthalic acid monoester to a polypeptide having MHETase activity under conditions sufficient to allow the polypeptide to convert the terephthalic acid monoester to terephthalic acid and an alcohol, wherein the terephthalic acid monoester is not mono-(2-hydroxyethyl) terephthalate.

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.

A method for preparing a recycled raw material uses a waste copolyester. The method for preparing a recycled raw material includes (1) depolymerizing a 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 a 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.

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 development of acrylated biomonomers produced from vegetable oil derivatives with a high degree of unsaturation allows the production of esters with a high content of epoxy precursor for the production of acrylated monomers with a high content of unsaturations capable of producing excellent varnishes. Starting with common and widely available oils such as soybean and similar oils, removing the saturated part, thus generating materials with a high degree of unsaturation similar to fatty materials derived from linseed oil. These biomonomers and their respective biopolymers in applications have demonstrated excellent performance, durability, are odorless, cure quickly, are biodegradable and economically more attractive.

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.