WO1998003459A1 - The method of obtaining terephtalic acid and ethylene glycol, particularly from poly/ethyleneterephtalate/wastes and the plant for realisation of this method - Google Patents

The method of obtaining terephtalic acid and ethylene glycol, particularly from poly/ethyleneterephtalate/wastes and the plant for realisation of this method Download PDF

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Publication number
WO1998003459A1
WO1998003459A1 PCT/IB1997/000847 IB9700847W WO9803459A1 WO 1998003459 A1 WO1998003459 A1 WO 1998003459A1 IB 9700847 W IB9700847 W IB 9700847W WO 9803459 A1 WO9803459 A1 WO 9803459A1
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Prior art keywords
ethylene glycol
autoclave
acid
advantageously
wastes
Prior art date
Application number
PCT/IB1997/000847
Other languages
French (fr)
Inventor
Heinrich Smuda
Original Assignee
Cet Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cet Gmbh filed Critical Cet Gmbh
Priority to AU31866/97A priority Critical patent/AU3186697A/en
Publication of WO1998003459A1 publication Critical patent/WO1998003459A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/09—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis
    • C07C29/095—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrolysis of esters of organic acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/09—Preparation of carboxylic acids or their salts, halides or anhydrides from carboxylic acid esters or lactones
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
    • C08J11/16—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with inorganic material
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
    • C08J2367/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
    • 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 subject of an invention is the method of obtaining terephtalic acid
  • ethylene glycol particularly from poly/ethyleneterephtalate/ wastes and the plant for realisation of this method.
  • poly/ethyleneterephtalate/ is carried out mainly in the alkaline medium
  • hydrolysis products i.e. ethylene glycol and terephtalic acid.
  • the method known here to fore, was carried out under normal or slightly
  • the reactor was usually included into the plant comprising means for washing and breaking up a polyester sub-
  • Carbon dioxide coming out during the reaction, is extracted continously from the reaction medium by a constant pressure and it is absorbed in an aqueous solution of alkali metal hydroxide, advantageously Na or K or ammonia water, until saturated.
  • alkali metal hydroxide advantageously Na or K or ammonia water
  • reaction mixture after separation of solid impurities and cooling, is subjected to oxidation, advantageously in an aqueous hydrogen peroxide solution of concentration 3% b.w. and then it is neutralised with an acid
  • terephtalic acid is finished. From a yielded suspension of terephtalic acid in a solution of ethylene gly- col and neutralisation acid salt a solid phase is separated and then puri ⁇
  • the autoclaves are linked through the four-way pressure valve such, that a vent pipe of the first autoclave is connected with a saturation pipe of the second autoclave while the reaction of the hydrolytic decomposition of sub ⁇
  • autoclave is connected with a saturation pipe of the first autoclave while the hydrolytic decomposition is carried out in the second autoclave.
  • An outlet of the neutraliser is connected to the device separating a liquid
  • the plant comprises two heated autoclaves 1, 2, every provided with a
  • the autoclaves 1, 2 are connected through the four-way pressure valve 9
  • ester raw material is carried out in the first autoclave 1, and a vent pipe 5
  • the outlet of a neutraliser 15 is connected to the centrifuge 16, which is
  • the first autoclave 1 is filled with a carbonate solution and broken and washed raw polyester
  • Carbon dioxide released during the reaction is extracted from the reaction medium by a constant pressure through a vent pipe 5 of the first auto ⁇
  • the autoclaves 1, 2 work changeably in such a way, that after the hydro-
  • clave 1 is made empty and filled with an aqueous solution of hydroxide
  • polyester raw material is introduced into the second autoclave 2, just
  • composition is carried out in the second autoclave 2 in a method according
  • a content of changeably working autoclaves 1, 2 is supplied through a cut
  • Cooled reaction mixture is directed to an
  • Example 1 In the first autoclave I of a plant according to the invention
  • the content of an autoclave has
  • the pressure non-return valve was adjusted on 25 MPa.
  • reaction mixture was hot filtered in a carbon filter 11 and then
  • fuged deposit was dried in a drier 20 giving terephtalic acid in amount of
  • Example 2 In the first autoclave 1 of a plant according to the invention
  • the precipitated deposit of terephtalic acid was washed several times with a hot water in a centrifuge 16 up to the loss of hydrogen ions.
  • fuged deposit was dried in a drier 20 giving terephtalic acid in amount of
  • Example 3 In the first autoclave 1 of a plant according to the invention
  • the content of an autoclave has
  • reaction mixture was hot filtered in a carbon filter U and then
  • the precipitated deposit of terephtalic acid was washed several times with a hot water in a centrifuge 16 up to the loss of hydrogen ions.
  • fuged deposit was dried in a drier 20 giving terephtalic acid in amount of
  • Example 4 In the first autoclave 1 of a plant according to the invention
  • poly/etheleneterephtalate/ in a form of cut waste X-ray film was placed in amount of 100 parts by weight and 20% sodium carbonate solution in amount of 55,3 parts by weight was added.
  • the content of an autoclave has been heated in 200°C till the evolution carbon dioxide was completed.
  • the precipitated deposit of terephtalic acid was washed several times with a hot water in a centrifuge 16 up to the loss of hydrogen ions.
  • fuged deposit was dried in a drier 20 giving terephtalic acid in amount of

Abstract

The subject of the invention is the method of obtaining of terephtalic acid and ethylene glycol, particularly from poly/ethyleneterephtalate/wastes comprising a hydrolytic decomposition of polyester with an aqueous solution of alkali metal or ammonium carbonate at the increased temperature and under the increased pressure, oxidation and neutralisation of a reaction mixture, separation of the product phases and purification of ethylene glycol by distillation and the plant for realisation of this method.

Description

The method of obtaining of terephtalic acid and ethylene glycol, particularly from poly/ethyleneterephtalate/ wastes
and the plant for realisation of this method
The subject of an invention is the method of obtaining terephtalic acid and
ethylene glycol, particularly from poly/ethyleneterephtalate/ wastes and the plant for realisation of this method.
Still growing amount of poly/ethyleneterephtalate/ produced world-wide,
which is used as a popular material for the production of bottles and containers, industrial forms, insulating foils and other daily used articles, be- sides many utilitary values, causes a fast growth of the amount of wastes.
The chemical nature of poly/ethyleneterephtalate/, which is especially re¬
sistant against the long-term action of extremely severe atmospheric conditions, causes that wastes do not undergo nor to a biodegradation nor to the natural destruction, and they lay unchanged as a very difficult pollution of
the natural environment.
Simultaneously, the raw materials for poly/ethyleneterephtalate/ production, i.e. ethylene glycol and terephtalic acid, are still rather expensive.
The known method of recycling poly/ethyleneterephtalate/ wastes in a form
of regranulate, added to the original plastic during forming processes does
not solve the waste problem and, similarly as a harmful combustion of wastes - it is only a half measure.
There is also known a method of a hydrolytic decomposition of
poly/ethyleneterephtalate/ to ethylene glycol and low-molecular deriva- tives of terephtalic acid. Hydrolytic decomposition of
poly/ethyleneterephtalate/ is carried out mainly in the alkaline medium,
particularly in NaOH, as it has been presented in the american patent descriptions nos 3,544,622 and 3,317,519.
Also from the American patent description no 4,522,239 there is known a
method of alkaline hydrolysis of polyesters, using ammonium hydroxide. Although in a result of these processes the noxious polyester wastes are eliminated and the valuable raw materials for, among others, poly/ethyleneterephtalate/ production, are obtained, but a strong alkaline
medium of a reaction causes, the yielded products are very impure. Carrying the process at high pH values gives a fast advance of a hydrolysis
reaction, but simultaneously in these conditions the secondary side-
reactions go very easily, giving the products to be undesired impurities of
the hydrolysis products, i.e. ethylene glycol and terephtalic acid. The method, known here to fore, was carried out under normal or slightly
increased pressure , in a continous or semi-continous mode, using the
heated, typical reactors with substrate dosing devices, mixers, pipe connec¬
tions, reflux or distillation column. The reactor was usually included into the plant comprising means for washing and breaking up a polyester sub-
strates, and the products purification system by washing, recrystalization
and drying the separated terephtalic acid or its solid derivatives and distilling ethylene glycol from a solution. In the method according to an invention, properly milled poly/ethyleneterephtalate/ wastes are treated with the aqueous solution of
alkali metal carbonate or ammonium carbonate while increasing gradually temperature, adventageously up to 200°C, and kept untill all polyester is
solubilised. Carbon dioxide, coming out during the reaction, is extracted continously from the reaction medium by a constant pressure and it is absorbed in an aqueous solution of alkali metal hydroxide, advantageously Na or K or ammonia water, until saturated.
The reaction mixture, after separation of solid impurities and cooling, is subjected to oxidation, advantageously in an aqueous hydrogen peroxide solution of concentration 3% b.w. and then it is neutralised with an acid
solution, advantageously mineral acid solution, till the precipitation of
terephtalic acid is finished. From a yielded suspension of terephtalic acid in a solution of ethylene gly- col and neutralisation acid salt a solid phase is separated and then puri¬
fied by washing and / or recrystalisation and dried to give terephtalic acid of a demanded water content. After a vaporisation of water and separation of salts of an acid used in neutralisation, ethylene glycol is distilled from the remained solution.
The plant for obtaining terephtalic acid and ethylene glycol, particularly from poly/ethyleneterephtalate/, in a method according to the invention
comprises at least two heated autoclaves, every provided with a mixer, a closed charging hole, advantageously with a hermetic raw material sup- plying system, a vent pipe with a pressure not-return valve and a saturation pipe, connected inside an autoclave with a bubbler.
The autoclaves are linked through the four-way pressure valve such, that a vent pipe of the first autoclave is connected with a saturation pipe of the second autoclave while the reaction of the hydrolytic decomposition of sub¬
strates is carried out in the first autoclave, and a vent pipe of the second
autoclave is connected with a saturation pipe of the first autoclave while the hydrolytic decomposition is carried out in the second autoclave.
The outlets of autoclaves are linked through the joint valve with a device
separating solid impurities from the reaction solution, advantageously a carbon filter, and a cooler, which outlet is lead consequently to the oxidiser and then , advantageously through a filter, to the neutraliser.
An outlet of the neutraliser is connected to the device separating a liquid
phase from a solid phase, advantageously a centrifuge, which reflux is lead, advantageously through the evaporator, to the distillation column and the solid residue is transported to the washing device and or crys-
talizer and the drier.
The plant according to the invention is shown in the exemplary execution on the enclosed drawing.
The plant comprises two heated autoclaves 1, 2, every provided with a
mixer 3, closed charging hole 4, connected with a hermetic raw material
supplying system, a vent pipe 5 with a pressure not-return valve 6 and a saturation pipe 7, which is connected to a bubbler 8 mounted inside every
autoclave 1, 2.
The autoclaves 1, 2 are connected through the four-way pressure valve 9
so, that a vent pipe 5 of the first autoclave 1 is connected to the saturation
pipe 7 of the second autoclave 2 while a hydrolytic decomposition of a poly¬
ester raw material is carried out in the first autoclave 1, and a vent pipe 5
of the second autoclave 2 is connected to the saturation pipe 7 of the first
autoclave 1 while a hydrolytic decomposition is carried out in the second
autoclave %
The outlets of autoclaves 1, 2 are linked through the joint valve 10 with a
carbon filter 11 and a cooler 12, which outlet is connected to the oxidiser
13 and then through the intermediate carbon filter 14 to the neutraliser
15
The outlet of a neutraliser 15 is connected to the centrifuge 16, which is
connected through the evaporator 17 to the distillation column 18 and to
the washing device 19 and a drier 20.
During a process carried out according to the invention the first autoclave 1 is filled with a carbonate solution and broken and washed raw polyester
material, consisting of the different forms of poly/ethyleneterephtalate/.
Carbon dioxide released during the reaction is extracted from the reaction medium by a constant pressure through a vent pipe 5 of the first auto¬
clave I and a four-way pressure valve 9 to a saturation pipe 5 of the second autoclave 2, which is filled with an aqueous solution of hydroxide. Carbon
dioxide is introduced through a bubbler into a content of the second auto¬
clave 2 and it is absorbed giving a carbonate water solution.
The autoclaves 1, 2 work changeably in such a way, that after the hydro-
lytic decomposition process in the first autoclave 1 is completed, the auto¬
clave 1 is made empty and filled with an aqueous solution of hydroxide,
while polyester raw material is introduced into the second autoclave 2, just
containing previously created aqueous carbonate solution. After the appropriate adjustment of the four-way pressure valve is done a hydrolytic de-
composition is carried out in the second autoclave 2 in a method according
to the invention, absorbing the released carbon dioxide in the first auto¬
clave 1.
A content of changeably working autoclaves 1, 2 is supplied through a cut
-off valve 10 to a carbon filter 11 to remove solid impurities and dyes, and
then it is cooled in a cooler 12. Cooled reaction mixture is directed to an
oxidiser 13, supplied with a hydrogen peroxide solution in the amount
causing an oxidation of the yielded side-products, and then, after filtering
on an intermediate carbon filter 14 it gets into a neutraliser 15, where it is
acidified till the complete precipitation of terephtalic acid. The resulted
suspension of terephtalic acid in an aqueous solution of ethylene glycol and
created mineral acid salt is separated in a centrifuge 16. The reflux, being
a raw ethylene glycol, after evaporation of water in an evaporator 17 and a
separation of a precipitated salt is directed to a distillation column 18, where it is subjected to the further purification. The deposit of terephtalic
acid separated in a centrifuge 16 is washed and dried.
Example 1 . In the first autoclave I of a plant according to the invention
poly/etheleneterephtalate/ in a form of waste textile fibres was placed in
amount of 100 parts by weight and 15% sodium carbonate solution in
amount of 55,3 parts by weight was added. The content of an autoclave has
been heated in 200 C till the evolution of carbon dioxide was completed.
The pressure non-return valve was adjusted on 25 MPa. The evolved car¬
bon dioxide was absorbed in the second autoclave 2, containing sodium
hydroxide in amount of 41,7 parts by weight in a form of an aqueous solu¬
tion. The reaction mixture was hot filtered in a carbon filter 11 and then
cooled in a cooler 12 and oxidized in a oxidizer 13 with a 39c hydrogen per¬
oxide solution. The resulted solution was filtered again in an intermediate
carbon filter 14 and then directed to a neutralizer 15, containing 15%
aqueous solution of sulphuric acid equivalent to 51,1 parts by weight of a
pure acid.
The precipitated deposit of terephtalic acid was washed several times with
hot water in a centrifuge 16 up to the loss of hydrogen ions. The centri-
fuged deposit was dried in a drier 20 giving terephtalic acid in amount of
86,4 parts by weight. The reflux from a centrifuge 16, containing an aque¬
ous solution of ethylene glycol and sodium sulphate was subjected to the
evaporation of water, giving sodium sulphate deposit and a raw ethylene glycol. The distillation of a raw ethylene glycol gave the purified ethylene glycol in amount of 30 parts by weight.
Example 2. In the first autoclave 1 of a plant according to the invention
poly/etheleneterephtalate/ in a form of waste, broken bottles was placed in
amount of 100 parts by weight and 15% potassium carbonate solution in amount of 72,0 parts by weight was added. The content of an autoclave has been heated in 200°C till the evolution carbon dioxide was completed. The
pressure non-return valve was adjusted on 25 MPa. The evolved carbon
dioxide was absorbed in the second autoclave 2, containing potassium hy-
droxide in amount of 58,3 parts by weight in a form of an aqueous solution. The reaction mixture was hot filtered in a carbon filter U and then cooled
in a cooler 12 and oxidised in a oxidiser 13 with a 3% hydrogen peroxide.
The resulted solution was filtered again in an intermediate carbon filter 14
and then directed to a neutraliser 15, containing 15% aqueous solution of
sulphuric acid equivalent to 51,1 parts by weight of a pure acid.
The precipitated deposit of terephtalic acid was washed several times with a hot water in a centrifuge 16 up to the loss of hydrogen ions. The centri-
fuged deposit was dried in a drier 20 giving terephtalic acid in amount of
86,5 parts by weight. The reflux from a centrifuge 16, containing an aque-
ous solution of ethylene glycol and potassium sulphate was subjected to the evaporation of water, giving potassium sulphate deposit and a raw ethyl¬
ene glycol. The distillation of a raw ethylene glycol gave the purified ethyl¬
ene glycol in amount of 31 parts by weight. Example 3. In the first autoclave 1 of a plant according to the invention
poly/etheleneterephtalate/ in a form of waste textile fibres was placed in
amount of 100 parts by weight and 20% ammonium carbonate solution in
amount of 50,0 parts by weight was added. The content of an autoclave has
been heated in 200°C till the evolution carbon dioxide was completed. The
pressure non-return valve was adjusted on 25 MPa. The evolved carbon
dioxide was absorbed in the second autoclave 2, containing ammonium
hydroxide in amount of 36,5 parts by weight in a form of an aqueous solu¬
tion. The reaction mixture was hot filtered in a carbon filter U and then
cooled in a cooler 12 and oxidised in a oxidiser 13 with a 3% hydrogen per¬
oxide. The resulted solution was filtered again in an intermediate carbon filter 14 and then directed to a neutraliser 15, containing 15% aqueous
solution of sulphuric acid equivalent to 51,1 parts by weight of a pure acid.
The precipitated deposit of terephtalic acid was washed several times with a hot water in a centrifuge 16 up to the loss of hydrogen ions. The centri-
fuged deposit was dried in a drier 20 giving terephtalic acid in amount of
86,4 parts by weight. The reflux from a centrifuge 16, containing an aque¬
ous solution of ethylene glycol and ammonium sulphate was subjected to the evaporation of water, giving ammonium sulphate deposit and a raw ethylene glycol. The distillation of a raw ethylene glycol gave the purified
ethylene glycol in amount of 32 parts by weight.
Example 4. In the first autoclave 1 of a plant according to the invention
poly/etheleneterephtalate/ in a form of cut waste X-ray film was placed in amount of 100 parts by weight and 20% sodium carbonate solution in amount of 55,3 parts by weight was added. The content of an autoclave has been heated in 200°C till the evolution carbon dioxide was completed. The
pressure non-return valve was adjusted on 25 MPa. The evolved carbon
dioxide was absorbed in the second autoclave 2, containing sodium hy¬
droxide in amount of 41,7 parts by weight in a form of an aqueous solution. The reaction mixture was hot filtered in a carbon filter H and then cooled
in a cooler 12 and oxidised in a oxidiser 13 with a 3% hydrogen peroxide
solution. The resulted solution was filtered again in an intermediate car¬
bon filter 14 and then directed to a neutraliser 15, containing 15% aqueous
solution of sulphuric acid equivalent to 51,1 parts by weight of a pure acid.
The precipitated deposit of terephtalic acid was washed several times with a hot water in a centrifuge 16 up to the loss of hydrogen ions. The centri-
fuged deposit was dried in a drier 20 giving terephtalic acid in amount of
85,0 parts by weight. The reflux from a centrifuge 16, containing an aque¬
ous solution of ethylene glycol and sodium sulphate was subjected to the evaporation of water, giving sodium sulphate deposit and a raw ethylene
glycol. The distillation of a raw ethylene glycol gave the purified ethylene
glycol in amount of 31 parts by weight. The results of the chemical analysis of terephtalic acid obtained in the
above examples using a method according to the invention in a plant ac¬
cording to the invention is shown in a table no 1. Table no 1. The results of the chemical analysis of terephtalic acid.
Test example 1 example 2 example 3 example 4 acid number , mg KOH/g 675.1 674, 1 674.0 673.0
Na+ content , ppm 29,5 1,85 1.80 75.5
K+ content , ppm 1,1 15,6 17,4 27.0
4-carboxybenzoic aldehyde 18,1 15,6 17,4 27,0 content, ppm benzoic acid content, ppm 20 20 17 18 p-toluic acid content, ppm 18 28 36 144 water content, ppm 0.12 0,06 0, 14 0.13

Claims

The patent claims 1. The method of obtaining terephtalic acid and ethylene glycol, particularly from polyethyljene wastes, comprising a hydrolytic decomposition
of polyester in an alkali medium at the increased temperature and un-
der the increased pressure, neutralisation of a reaction mixture, separation of the product phases and purification of ethylene glycol by distillation, characterised in that the broken poly/ethyleneterephtalate/
wastes are treated with an aqueous solution of alkali metal or ammonium carbonate, increasing the temperature gradually, advantageously to 200°C and taking off carbon dioxide from a reaction mixture by a constant pressure, and then a reaction mixture, after separation of solid
impurities and cooling is subjected to an oxidation, advantageously with an aqueous hydrogen peroxide solution, and then neutralised with an
aqueous acid solution, advantageously mineral acid , and from the re-
suited suspension a solid phase is separated and purified, advanta¬
geously by washing and or crystalisation, and washed, when at least a part of water is evaporated from a resident solution and a salt of neu¬
tralising acid is separated, ethylene glycol is separated, advantageously
using distillation.
2. A method as claimed in claim 1, characterised in that carbon dioxide
evolved in a reaction is absorbed in an aqueous solution of ammonia or
alkali metal hydroxide, advantageously Na or K.
3. A method as claimed in claim 1, characterised in that carbonate re¬
sulted from absorption of carbon dioxide is used in a consequent process, carried out according to the invention.
4. The plant for obtaining terephtalic acid and ethylene glycol, particularly
from poly/ethyleneterephtalate/ wastes, comprising a heated autoclave, provided with a mixer, closed charging hole with a hermetic substrate dosing system and pipes, neutraliser and the devices for separation of
phases and purification of solid and liquid phase, characterised in
that it comprises at least two heated autoclaves (1,2), every provided
with a mixer (3), closed charging hole (4), outlet pipe (5) provided with a
pressure non-return valve (6) and saturation valve (7), connected with
bubblers (8) placed inside the autoclaves (1,2), which are connected
through a four- way pressure valve (9) so, that an outlet pipe (5) of the
first autoclave (1) is connected with a saturation pipe of the second auto-
clave (2) while the process is run in the first autoclave (1), and an outlet
pipe (5) of the second autoclave (2) is connected to the saturation pipe
(7) of the first autoclave (1) while the process is run in the second auto¬
clave (2), wherein the autoclaves (1, 2) bottom outlets are connected
through a joint valve (10) with a solid phase separating device, advan-
tageously a carbon filter (H) and a cooler (12), which outlet is connected
to the oxidiser (JL3), and then, advantageously through an intermediate
carbon filter (14) to a neutraliser (15), which outlet is linked with a solid phase separating device, advantagenously a centrifuge (16), which is
connected with a distillation column (18) and with a washing device
and/or crvstaliser with a drier.
PCT/IB1997/000847 1996-07-19 1997-07-08 The method of obtaining terephtalic acid and ethylene glycol, particularly from poly/ethyleneterephtalate/wastes and the plant for realisation of this method WO1998003459A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU31866/97A AU3186697A (en) 1996-07-19 1997-07-08 The method of obtaining terephtalic acid and ethylene glycol, particularly from poly/ethyleneterephtalate/wastes and the plant for realisation of this method

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19629042A DE19629042C2 (en) 1996-07-19 1996-07-19 Process for the production of terephthalic acid and ethylene glycol, in particular from polyethylene terephthalate waste, and device for carrying out the process
DE19629042.2 1996-07-19

Publications (1)

Publication Number Publication Date
WO1998003459A1 true WO1998003459A1 (en) 1998-01-29

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WO2016153368A1 (en) 2015-03-20 2016-09-29 RS PET Społka z o.o. Installation for continuous treatment of polyethylene terephthalate pet waste
US9550713B1 (en) 2015-07-09 2017-01-24 Loop Industries, Inc. Polyethylene terephthalate depolymerization
US10252976B1 (en) 2017-09-15 2019-04-09 9449710 Canada Inc. Terephthalic acid esters formation
US10808096B2 (en) 2018-06-25 2020-10-20 9449710 Canada Inc. Terephthalic acid esters formation
US11248103B2 (en) 2019-03-20 2022-02-15 9449710 Canada Inc. Process for the depolymerization of polyethylene terephthalate (PET)
WO2022035725A1 (en) * 2020-08-10 2022-02-17 Auriga Polymers, Inc. Process for purification of recovered glycol from chemical recycling of waste polyester

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DE19641743B4 (en) 1996-10-10 2004-04-01 Cet-Umwelttechnik-Entwicklungsgesellchaft Mbh Process for the recovery of liquid fuels from polyolefin waste
ATE226187T1 (en) * 2000-02-29 2002-11-15 Massimo Broccatelli METHOD FOR RECOVERING TEREPHTHAL ACID FROM A MATERIAL CONTAINING POLY(ETHYLENE TEREPHTHALATE).
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US6720448B2 (en) 2000-10-11 2004-04-13 Massimo Broccatelli Method of recovering chemical species by depolymerization of poly (ethylene terephthalate) and related use
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US10793508B2 (en) 2017-09-15 2020-10-06 9449710 Canada Inc. Terephthalic acid esters formation
US10252976B1 (en) 2017-09-15 2019-04-09 9449710 Canada Inc. Terephthalic acid esters formation
US11866404B2 (en) 2017-09-15 2024-01-09 9449710 Canada Inc. Terephthalic acid esters formation
US10808096B2 (en) 2018-06-25 2020-10-20 9449710 Canada Inc. Terephthalic acid esters formation
US11401398B2 (en) 2018-06-25 2022-08-02 9449710 Canada Inc. Terephthalic acid esters formation
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