CN1209801A - Process for producing terephthalic acid - Google Patents
Process for producing terephthalic acid Download PDFInfo
- Publication number
- CN1209801A CN1209801A CN95198019A CN95198019A CN1209801A CN 1209801 A CN1209801 A CN 1209801A CN 95198019 A CN95198019 A CN 95198019A CN 95198019 A CN95198019 A CN 95198019A CN 1209801 A CN1209801 A CN 1209801A
- Authority
- CN
- China
- Prior art keywords
- terephthalic acid
- acid
- terephthaldehyde
- alkaline earth
- production method
- Prior art date
- Legal status (The legal status 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 status listed.)
- Granted
Links
Images
Classifications
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/582—Recycling of unreacted starting or intermediate materials
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
This invention relates to a process for manufacturing terephthalic acid and more particularly, to a process for manufacturing terephthalic acid in a high recovery rate with high purity in accordance with the practice of this invention comprising the following procedures: polyethylene terephthalate (hereinafter referred to as "PET") scrap is hydrolyzed with alkaline aqueous solution to give the slurry of terephthalic acid alkali metal/earth metal salt, then the particles of terephthalic acid formed from acid-neutralization are enlarged to recover terephthalic acid with high purity.
Description
Background of invention
Invention field
The present invention relates to a kind of production method of terephthalic acid, more particularly, relate to a kind of method with high-recovery production high purity terephthalic acid, according to the present invention, this method may further comprise the steps: obtain the slurries of the basic metal/alkaline earth salt of terephthalic acid with alkaline solution hydrolysis polyethylene terephthalate (to call " PET " in the following text) fragment, then, the terephthaldehyde's granulates that is formed by the acid neutralization is grown up, reclaim highly purified terephthalic acid.
Pet waste is discharged by the final user who uses them, is meant the broken yarn of polyester that produces in broken polyester textile, the broken bottle of PET, the broken container of PET, the polyethylene terephthalate fragment that produces in the PET polymerization production process or trevira, yarn and the fabric production process.Because the PET fragment that discharges in daily life and the production process constantly increases, from reducing production costs and solving the viewpoint of environmental problem, the utilization again of PET fragment becomes key subjects.Recently proposed to reclaim the whole bag of tricks of terephthalic acid, but they are ineffective, are uneconomic from the PET fragment.
Use the ordinary method of production of PET fragment and recovery terephthalic acid as follows:
At US 3,120, in 561 and 4,578,502, PET is by hydrolysis under high temperature and high pressure, cooling and crystallization fast, to reclaim sedimentary terephthalic acid.
At US 3,884, in 850, use two (hydroxyethyl) terephthalate to come to reclaim terephthalic acid from PET as solvent.
At UK 2,123, in 403 and JP-A-3-16,328, at 200-300 ℃ with have under the condition that discoloring agent exists, with as the solvent hydrolysis PET of water, the decompression cooling is with the recovery terephthalic acid then.
At US 3,952, in 053, there are two kinds to reclaim method of terephthalic acid: a) by using sulphuric acid hydrolysis from PET, with mixing solutions that water precipitation obtained is made up of terephthalic acid and sulfuric acid to reclaim terephthalic acid, or b) PET is put in the aqueous solution of sodium hydroxide precipitation and remove insolubles, adds sulfuric acid to be settled out terephthalic acid.Then, after having reclaimed terephthalic acid, take out ethylene glycol and rectifying with organic solvent extracting.
At US 4,355, in 175, the PET acid hydrolysis is with the cold water dilution and filter immediately.Gained solution is dissolved in the alkaline hydrated oxide solution being settled out impurity, and is removed, and adds sulfuric acid precipitation and goes out terephthalic acid.Filtering solution washes with water also dry to reclaim terephthalic acid then.
At US 3,544, in 622, at 150 ℃ with have under the condition that ethylene glycol exists, PET sodium hydroxide solution saponification prepares disodium terephthalate.Then, filter gained solution, the aqueous solution of spent glycol or disodium terephthalate is washing more than 90 ℃, and is dissolved in the water.Under 90 ℃, in solution, add gac, stir and neutralize with sulfuric acid.Then, filter out terephthalic acid, and wash with water to reclaim terephthalic acid.
In EP 497,662, under normal pressure and 140-180 ℃, the reaction of the oxyhydroxide of PET and basic metal/alkaline-earth metal, the basic metal/alkaline earth salt of preparation terephthalic acid.This substance dissolves in water, is used C
3-C
8Alcohol extracts impurity, with the acid neutralization, then filters to reclaim terephthalic acid then.
In EP 597,751, under the condition that has the extrusion machine to exist, PET and sodium hydroxide reaction do not add solvent, then, resulting disodium terephthalate are dissolved in the water, by gac, neutralize with sulfuric acid.Resulting solution is filtered, washs to reclaim terephthalic acid.
At US 5,395, in 858, the PET of heating for dissolving in sodium hydroxide prepares disodium terephthalate and ethylene glycol.The gained material is heated to temperature more than the boiling point of ethylene glycol with evaporating solns.Remaining disodium terephthalate is dissolved in the water and with the acid neutralization to reclaim terephthalic acid.
There are the following problems for these methods of being reported: a) the great majority reaction is carried out under high temperature and high pressure, b) all there is not explanation to remove the method for impurity and supervision purity, c), do not analyze the purity of terephthalic acid with quality measurement by appropriate means even under the situation that has monitored purity yet.In addition, in filtering the method for terephthalic acid as final step, the terephthalic acid particle diameter should fully be grown up, because short grained terephthalic acid makes separating of solid and liquid insufficient, causes the rate of recovery to reduce, and also can make the dry difficulty that takes place.Therefore, all methods are not mentioned any method that the terephthalic acid particle diameter is grown up.
On this meaning, institute's reported method is unfavorable to industrialization technically and economically, and, on the improvement environmental problem, also there is very big space, because institute's reported method does not advise handling the method for the by product that produces in the removal process.
The accompanying drawing summary
Accompanying drawing is a schema of describing production terephthalic acid process of the present invention.
The invention summary
Therefore, the purpose of this invention is to provide a kind of production method of terephthalic acid, comprise following process in force: with the alkaline aqueous solution hydrolysis PET that contains treating compound, by acid neutralization preparation terephthalic acid.Because the technology of under the technical qualification of gentleness, using easy method that terephthaldehyde's granulates is grown up, can produce highly purified terephthalic acid, in addition, solvent of discharging in the reaction process and reactant can return with recycling, therefore, reduced the production cost of terephthalic acid.
Detailed description of the present invention
The present invention can describe in the following manner in more detail.
The invention is characterized in the terephthalic acid production method that comprises the steps: (a) under the condition that solvent and treating compound just like water exist, prepare the basic metal/alkaline earth salt of terephthalic acid with the oxyhydroxide hydrolysis PET fragment of basic metal/alkaline-earth metal; (b) aqueous solution that will be dissolved in the terephthaldehyde's acid alkali metal/alkaline earth salt in the water is separated into solid and liquid; Solid returns described (a) hydrolysing step or discharging, liquid is transported to next adsorption step; (c) aqueous solution of terephthaldehyde's acid alkali metal/alkaline earth salt is adsorbed, and obtains terephthalic acid with the acid neutralization; (d) crystallization so that terephthaldehyde's granulates grow up; (e) and, cooling terephthaldehyde's granulates of growing up under reduced pressure filters and dry.
The invention still further relates to several jars of installing from the order of PET fragment raw material production terephthalic acid of being used for, it is characterized in that comprising with lower device: hydrolysis device (1), the hydrolysis therein of described PET fragment, preparation terephthaldehyde acid alkali metal/alkaline earth salt; Dissolver (2), terephthaldehyde's acid alkali metal/alkaline earth salt dissolves therein; Centrifugal device (3); Adsorption tower (4); Neutralising arrangement (5) is therein with preparing terephthalic acid with terephthaldehyde's acid alkali metal/alkaline earth salt in the acid; Crystallization apparatus (6), terephthaldehyde's granulates is grown up therein; Refrigerating unit (7); Filtration unit (8), terephthaldehyde's granulates of growing up filters therein; Drying installation (9), filtering terephthalic acid are dry therein.
The present invention is described in more detail following.
According to the present invention, the alkaline aqueous solution hydrolysis of PET fragment is with the slurries of preparation terephthaldehyde acid alkali metal/alkaline earth salt.Then, gained solution is dissolved in the water, between adsorption cycle, removes impurity.With the preparation terephthalic acid, before reclaiming terephthalic acid, terephthaldehyde's granulates is fully grown up to improve the rate of recovery of terephthalic acid with sour neutralization solution.
The inventive method of producing terephthalic acid is with reference to the following drawings more detailed description:
,, in the oxyhydroxide (5-30 weight %) of PET fragment (1-25 weight %), basic metal/alkaline-earth metal, treating compound (the 1-30 weight %) retort of packing into (1), then, stir with agitator (1a), as solvent with water at 1-20kg/cm
2Pressure and 30-200 ℃ temperature under hydrolysis 30-120 minute, stirring velocity is 60-300rpm.During described hydrolysis reaction, in order to increase the reaction area of PET fragment, the PET fragment is cut into small-particle, and is crushed to less than 1cm
3, the retort of just packing into then (1).Therefore, with respect to the total amount of reactant, if the PET fragment that contains in the retort (1) less than 1 weight %, does not then possess economic and practical, if surpass 25 weight %, then the concentration of terephthalate is higher, and reaction is difficult to operate with efficient manner.Basic metal/the alkaline earth metal hydroxides that is used for the present invention is meant alkali metal hydroxide or alkaline earth metal hydroxides.For hydrolysis reaction, total amount with respect to reactant, if basic metal/alkaline earth metal hydroxides is less than 5 weight %, then the transformation efficiency in the reaction is lower, if surpass 30 weight %, since increase the internal circulating load of production cost and intermediate product, and can produce by product inevitably, therefore impracticable economically.According to the present invention, treating compound comprises C
1-C
4Pure and mild tensio-active agent.With respect to the total amount of reactant, if described treating compound less than 1 weight %, then speed of response is lower, if surpass 30 weight %, then the content of water can reduce relatively, has improved the concentration of terephthaldehyde's acid alkali metal/alkaline earth salt, therefore, viscosity raises, and is difficult to operate with efficient manner.In addition, if being lower than 30 ℃ or reaction pressure, the temperature of described hydrolysis reaction is lower than 1kg/cm
2, then speed of response can be quite low, and being proved to be is unpractical economically.
In contrast, if being higher than 200 ℃ or reaction pressure, the temperature of described hydrolysis reaction is higher than 20kg/cm
2, for keeping high temperature of reaction and pressure, then further improved the cost of investment and the cost of energy of equipment, make that this method is unpractical economically.Behind described hydrolysis reaction, PET is converted to terephthaldehyde's acid alkali metal/alkaline earth salt.At room temperature, the solubleness of terephthaldehyde's acid alkali metal/alkaline earth salt in water is about 13 weight %, will exist with the form of slurries.
The solution of terephthaldehyde's acid alkali metal/alkaline earth salt is transported to the dissolving vessel (2) from retort (1).In described solution, add entry, under the speed of 60-300rpm, stirred 1.0-60 minute, at normal pressure and the 20-100 ℃ of aqueous solution for preparing phthalic acid basic metal/alkaline earth salt down with agitator (2a).With respect to terephthaldehyde's acid alkali metal/alkaline earth salt slurries, use the water of 0.5-3.0 times of weight.If the amount of water is less than 0.5 times of weight, then terephthaldehyde's acid alkali metal/alkaline earth salt can not be water-soluble in a large number, promptly enables water-solublely in a large number, and the viscosity of described solution is also quite high, to such an extent as to follow-up adsorption step can not be operated effectively.If surpass the water of 3.0 times of weight, then the size of dissolving vessel and adsorption tower will be with the proportional amplification of increase of institute's water.The cost of investment of equipment and the running cost of reaction increase inevitably.Reaction in dissolving vessel (2) is preferably carried out under 20-100 ℃.In order to guarantee at next adsorption step higher adsorption efficiency is arranged, dissolution conditions preferably is no more than 100 ℃.The alcohol and water of evaporation is condensed, and returns retort (1).
Terephthaldehyde's acid alkali metal/alkaline-earth metal salt brine solution by dissolving vessel (2) is separated into solid and liquid by sedimentator (3); Contain unreacted reactant and not the solid of dissolved substance return retort (1) or discharging, and liquid is transported to adsorption tower (4).
Adsorption tower (4) works to remove the impurity (as metal, metallic compound, organic compound, dirt etc.) that is included among the PET.The purity of final product terephthalic acid is determined by the removal efficient of adsorption tower (4).According to the present invention, select the packing material of gac as adsorption tower (4), it is stable in basic solution, considers its rate of adsorption, the surface-area of unit volume gac is preferably at 500-1,500m
2In the scope of/g.Reaction in the adsorption tower (4) is preferably at 0.01-10.0kg/cm
2Pressure and 20-100 ℃ temperature under carry out, with the efficient of removing of further raising impurity.The suitable residence time of (4) is 1-60 minute in adsorption tower, and still, the residence time can transfer long or the accent weak point according to reaction pressure.
Terephthaldehyde's acid alkali metal/alkaline earth salt by adsorption tower (4) is admitted in the neutralization tank (5) with the acid neutralization.Under the stirring of the agitator (5a) in neutralization tank (5), described solution slowly mixes with the strong acid of example hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid.Then, terephthaldehyde's acid alkali metal/alkaline earth salt is neutralized, preparation terephthalic acid and corresponding alkali metal/alkaline earth salt.During neutralization reaction, two stoichiometric points have been formed; When the pH of described solution detects first stoichiometric point between 9.0-6.0, basic metal/alkaline earth metal hydroxides has been prepared basic metal/alkaline earth salt by the acid neutralization, when the pH of described solution detects second stoichiometric point between 4.0-2.0, terephthaldehyde's acid alkali metal/alkaline earth salt has been prepared terephthalic acid by the acid neutralization.During described neutralization, must constantly provide acid to reach 4.0-2.0 up to the pH of described solution.
After described neutralization reaction, because it has higher solubleness in water, the basic metal/alkaline earth salt that is obtained is dissolved in the water in a large number, and terephthalic acid is with the solid state crystallization simultaneously.Because crystalline terephthaldehyde granulates is so little, terephthalic acid is difficult to separate effectively with solid-liquid separation method (for example centrifugal or filtration).Even separate, its rate of recovery is also very low, is uneconomical practicality in industrial application.Therefore, according to the present invention, the terephthalic acid slurries that so obtain from described neutralization procedure are sent to the crystallizer (6), so that the terephthalic acid particle diameter is fully grown up.One to five crystallizer (6) is connected in series, and each crystallizer is operated by this way: its temperature progressively reduces.Because described device, particle diameter is progressively grown up, and therefore, can reduce small-particle.Tc in jar (6) is fallen preferred in 30-50 ℃ scope.
All crystallizers (6) must be operated under following specification: temperature 120-300 ℃, and pressure 2-86kg/cm
2, stirring velocity 60-300rpm.The residence time by crystallizer (6) is preferably 30-180 minute fully.In addition, because the crystallization of terephthalic acid is carried out under high temperature and high pressure, excessive acid can cause the corrosion of crystallizer (6).Consider this point, any acid that contains in the terephthalic acid slurries by described crystallisation step should be lower than 10 weight %.For crystallizer, should select the height corrosion-resistant material, as stainless steel 316 or titanium.
Terephthaldehyde's granulates of fully growing up in described crystallizer is admitted in next cooling tank (7), at 0.1-1.0kg/cm
2Pressure and 60-90 ℃ temperature under cool off.Therefore, the alcohol that contains in the slurries is evaporated with water.
The alcohol and water of evaporation is condensed, and returns retort (1) then.
Refrigerative terephthalic acid slurries are transported to strainer (8) to be separated to carry out solid-liquid.The service temperature of strainer (8) depends on the temperature of terephthalic acid slurries, preferably maintains 60-80 ℃.Pressure is preferably 0.1-0.8kg/cm
2According to described liquid-solid separation method, terephthalic acid comes out with the isolated in form of wet cake, and basic metal/alkaline earth salt occurs with the form of filtrate.The terephthalic acid that filters out washes with water, considers detersive efficiency, with respect to terephthalic acid (30-80 ℃), preferably uses 0.5-1.2 water doubly.
Terephthalic acid after the filtration is input to moisture eliminator (9), at 0.5-1.0kg/cm
2Pressure and 100-150 ℃ dry 10-120 minute down, obtain terephthalic acid, the finished product promptly of the present invention.
In addition, the filtrate that described filtration step is discharged is concentrated by transpiring moisture, or transpiring moisture not, and filtrate is sent in the electrodialyzer (10), uses bipolar membrane to be separated into acid and corresponding alkali metal/alkaline earth metal hydroxides.So separation and restored acid return neutralization tank (5), and oxyhydroxide then returns retort (1).
In more detailed mode, be included in basic metal/alkaline earth salt (being sodium-chlor and sodium sulfate) in the described filtrate by electrolysis.Then, basic metal/alkaline-earth metal ions is as Na
+Ion is by cationic membrane, by OH
-Ion fetters, and forms basic metal/alkaline earth metal hydroxides, as sodium hydroxide.Acidic anionic in addition is as Cl
-And SO
4 2-Ion is by anionic membrane, by H
+Ion fetters, and forms example hydrochloric acid and vitriolic acid.
Describe as top, the invention provides a kind of recycling and comprise the raw-material method of returning of discharging solvent from each production stage, therefore, reduced the cost of product, also solved the environmental problem that refuse causes simultaneously.Furtherly, from described production process so preparation and the terephthalic acid that reclaims can 98% or higher yield obtain.The present invention can illustrate in greater detail by following embodiment, but claims are not subjected to the restriction of these embodiment.
500g water and 30g sodium hydroxide are put into retort (1) and dissolving.Behind the PET fragment that adds 200g methyl alcohol and 10g pulverizing, mixture is at 8kg/cm
2Pressure and 150 ℃ temperature under, stirred 120 minutes with agitator (300rpm).
Reaction soln in the retort (1) is transferred to dissolving vessel (2), add 400g water, and (2a 60rpm) stirred 10 minutes with agitator down normal pressure and 65 ℃.
Terephthaldehyde's acid alkali metal/alkaline-earth metal salt brine solution by dissolving vessel (2) is separated into corresponding solid and liquid in sedimentator (3).
Solid returns retort (1).Contain the unreacted PET of 0.14g in described solid, the reactivity that is appreciated that PET is 98.6%.
Transfer to adsorption tower (4) by the liquid of sedimentator (3), at 0.01kg/cm
2Pressure and 30 ℃ temperature under absorption 1 minute.Having filled surface-area in the adsorption tower (4) is 1,500m
2The gac of/g.
The aqueous solution of the terephthaldehyde's acid alkali metal/alkaline earth salt by adsorption tower (4) is transferred to neutralization tank (5).Then, solution stirs with agitator (5a) in neutralization tank, and slowly adding hydrochloric acid, rises to 2.0 up to pH.The result that SEM monitors is, from the terephthalic acid particle grain size very little (5-20 μ m) of described neutralization procedure formation.
Described neutralization solution is put into crystallizer (6) so that the terephthalic acid particle diameter is grown up.Crystallizer (6) is made by stainless steel 316, and reaction requires as follows: temperature is 150 ℃, pressure 5kg/cm
2, stirring velocity is 60rpm.
The terephthalic acid slurries of fully growing up in described crystallizer (6) are admitted in next cooling tank (7), and the decompression cooling, and pressure is 1kg/cm
2, temperature is 90 ℃.The first alcohol and water that is evaporated is condensed and returns retort (1).Refrigerative terephthalic acid slurries are sent to strainer (8) to be separated into corresponding solid and liquid, and reaction pressure is 0.8kg/cm
2, temperature is 80 ℃.Then, reclaim the terephthalic acid of solid state.Terephthalic acid after the filtration is sent to moisture eliminator (9), is 1kg/cm in reaction pressure
2, temperature is 150 ℃ of following dryings 10 minutes, obtains the 8.5g terephthalic acid.
In addition, the filtrate of discharging from described strainer (8) is added to electrodialyzer (10), at this electrodialyzer 3 Room type bipolar membranes is arranged, and sodium-chlor contained in the filtrate is become hydrochloric acid and sodium hydroxide by electrolytic separation.After this, retort (1) and neutralization tank (5) are returned in described alkali and acid respectively.Embodiment 2
110g water and 60g sodium hydroxide are put into retort (1) and dissolving.After adding the PET fragment that 30g methyl alcohol, 1g tensio-active agent (SURMAX CS 727, Chemax Inc.) and 20g pulverize, mixture is under the temperature of normal pressure and 80 ℃, with agitator (200rpm) stirring 60 minutes.
Reaction soln in the retort (1) is transferred to dissolving vessel (2), add 400g water, and (2a 200rpm) stirred 30 minutes with agitator down normal pressure and 50 ℃.
Terephthaldehyde's acid alkali metal/alkaline-earth metal salt brine solution by dissolving vessel (2) is separated into corresponding solid and liquid in sedimentator (3).This solid returns retort (1).Contain the unreacted PET of 1.28g in described solid, the reactivity that is appreciated that PET is 93.6%.
Transfer to adsorption tower (4) by the liquid of sedimentator (3), at 0.1kg/cm
2Pressure and 50 ℃ temperature under absorption 10 minutes.Having filled surface-area in the adsorption tower (4) is 1,500m
2The gac of/g.
The aqueous solution of the terephthaldehyde's acid alkali metal/alkaline earth salt by adsorption tower (4) is transferred to neutralization tank (5).
Then, solution stirs with agitator (5a) in neutralization tank, and slowly at the sulfuric acid that adds 97%, becomes 4.0 up to pH.The result that SEM monitors is, from the terephthalic acid particle grain size very little (5-10 μ m) of described neutralization procedure formation.
Described neutralization solution is put into crystallizer (6) so that terephthaldehyde's granulates is grown up.Crystallizer (6) is made by stainless steel 316, has two placed in-line crystallizers, and the reaction of each requires as follows: pressure 15-25kg/cm
2, stirring velocity is 150rpm.In addition, the temperature of first crystallizer is measured as 200 ℃, and in this construction process, the temperature of described crystallizer progressively descends 50 ℃, and the total residence time by all crystallizers (6) is 60 minutes.
The terephthalic acid slurries of fully growing up in described crystallizer (6) are admitted in next cooling tank (7), and the decompression cooling, and pressure is 1kg/cm
2, temperature is 90 ℃.The first alcohol and water that is evaporated is condensed and returns retort (1).At pressure 0.5kg/cm
2, temperature is under 80 ℃, refrigerative terephthalic acid slurries are sent to strainer (8) to be separated into corresponding solid and liquid.Then, the form with warm filter cake reclaims terephthalic acid.Terephthalic acid after the filtration is sent to moisture eliminator (9), is 0.5kg/cm in reaction pressure
2, temperature is 150 ℃ of following dryings 60 minutes, obtains the 16.2g terephthalic acid.
In addition, the filtrate of discharging from described strainer (8) is added to electrodialyzer (10), at this electrodialyzer 3 Room type bipolar membranes is arranged, and sodium sulfate contained in the filtrate is become sulfuric acid and sodium hydroxide by electrolytic separation.After this, retort (1) and neutralization tank (5) are returned in described alkali and acid respectively.Embodiment 3
300g water and 150g sodium hydroxide are put into retort (1) and dissolving.Behind the PET fragment that adds 300g methyl alcohol, 5g tensio-active agent (SURMAX CS 727, Chemax Inc.) and 250g pulverizing, mixture is at 5kg/cm
2Pressure and 100 ℃ temperature under, stirred 120 minutes with agitator (100rpm).
Reaction soln in the retort (1) is transferred in the dissolving vessel (2), is added 1,500g water, and normal pressure and 50 ℃ (2a 300rpm) stirred 60 minutes with agitator down.Evaporate alcohol and water and be condensed and return retort (1).
Terephthaldehyde's acid alkali metal/alkaline-earth metal salt brine solution by dissolving vessel (2) is separated into corresponding solid and liquid at sedimentator (3).This solid returns retort (1).Contain the unreacted PET of 28.2 g in described solid, the reactivity that is appreciated that PET is 88.7%.
Transfer to adsorption tower (4) by the liquid of sedimentator (3), at 1kg/cm
2Pressure and 80 ℃ temperature under absorption 10 minutes.Having filled surface-area in the adsorption tower (4) is 1,500m
2The gac of/g.
The aqueous solution of the terephthaldehyde's acid alkali metal/alkaline earth salt by adsorption tower (4) is transferred to neutralization tank (5).Then, solution stirs with agitator (5a) in neutralization tank, and slowly at the sulfuric acid that adds 97%, becomes 3.2 up to pH.The result that SEM monitors is, from the terephthalic acid particle grain size very little (10 μ m) of described neutralization procedure formation.
Described neutralization solution is put into crystallizer (6) so that terephthaldehyde's granulates is grown up.Crystallizer (6) is made by titanium or stainless steel 316, has five placed in-line crystallizers, and the reaction of each requires as follows: pressure 2-86kg/cm
2, stirring velocity is 120-200rpm.In addition, the temperature of first crystallizer is measured as 300 ℃, and in this structure, the temperature of described crystallizer progressively descends 30-50 ℃, and the total residence time by all crystallizers (6) is 180 minutes.
The terephthalic acid slurries of fully growing up in described crystallizer (6) are admitted in next cooling tank (7), and the decompression cooling, and pressure is 0.1kg/cm
2, temperature is 90 ℃.The first alcohol and water that is evaporated is condensed and returns retort (1).At pressure is 0.1kg/cm
2, temperature is under 80 ℃, refrigerative terephthalic acid slurries are sent to strainer (8) to be separated into corresponding solid and liquid.Then, the form with wet cake reclaims terephthalic acid.Later terephthalic acid is sent to moisture eliminator (9), is 0.7kg/cm in reaction pressure
2, temperature is 100 ℃ of following dryings 180 minutes, obtains the 186.9g terephthalic acid.
In addition, the filtrate of discharging from described strainer (8) is added to electrodialyzer (10), at this electrodialyzer 3 Room type bipolar membranes is arranged, and sodium sulfate contained in the filtrate is become sulfuric acid and sodium hydroxide by electrolytic separation.After this, retort (1) and neutralization tank (5) are returned in described alkali and acid respectively.Embodiment 4
735g water and 50g sodium hydroxide are put into retort (1) and dissolving.
Behind the PET fragment that adds 100g methyl alcohol and 115g pulverizing, mixture is at 20kg/cm
2Pressure and 200 ℃ temperature under, stirred 60 minutes with agitator (300rpm).
Reaction soln in the retort (1) is transferred to dissolving vessel (2), add 1,000g water, and at 1kg/cm
2Pressure and 100 ℃ down (2a 300rpm) stirred 20 minutes with agitators.Evaporate alcohol and water and be condensed and return retort (1).
Terephthaldehyde's acid alkali metal/alkaline-earth metal salt brine solution by dissolving vessel (2) is separated into corresponding solid and liquid at sedimentator (3).This solid returns retort (1) or emits.Contain the unreacted PET of 0.16g in described solid, the reactivity that is appreciated that PET is 99.7%.
Transfer to adsorption tower (4) by the liquid of sedimentator (3), at 10kg/cm
2Pressure and 100 ℃ temperature under absorption 5 minutes.Having filled surface-area in the adsorption tower (4) is 900m
2The gac of/g.
The aqueous solution of the basic metal/alkaline earth salt by adsorption tower (4) is transferred to neutralization tank (5).Then, solution stirs with agitator (5a) in neutralization tank, and slowly at the sulfuric acid that adds 97%, becomes 2.0 up to pH.The result that SEM monitors is, from the terephthalic acid particle grain size very little (10-20 μ m) of described neutralization procedure formation.
Described neutralization solution is put into crystallizer (6) so that terephthaldehyde's granulates is grown up.
Crystallizer (6) is made by titanium or stainless steel 316, has three placed in-line crystallizers, and the reaction of each requires as follows: pressure 2-15kg/cm
2, stirring velocity is 200-300rpm.In addition, the temperature of first crystallizer is measured as 200 ℃, and in this structure, the temperature of described crystallizer progressively descends 30-50 ℃, and the total residence time by all crystallizers (6) is 60 minutes.
The terephthalic acid slurries of fully growing up in described crystallizer (6) are admitted in next cooling tank (7), and the decompression cooling, and pressure is 0.1kg/cm
2, temperature is 90 ℃.The first alcohol and water that is evaporated is condensed and returns retort (1).At pressure is 0.1kg/cm
2, temperature is under 80 ℃, refrigerative terephthalic acid slurries are sent to strainer (8) to be separated into corresponding solid and liquid.Then, the form with wet cake reclaims terephthalic acid.Terephthalic acid after the filtration is sent to moisture eliminator (9), is 0.8kg/cm in reaction pressure
2, temperature is 120 ℃ of following dryings 120 minutes, obtains the 99g terephthalic acid.
In addition, the filtrate of discharging from described strainer (8) is added to electrodialyzer (10), at this electrodialyzer 3 Room type bipolar membranes is arranged, and sodium sulfate contained in the filtrate is become sulfuric acid and sodium hydroxide by electrolytic separation.After this, retort (1) and neutralization tank (5) are returned in described alkali and acid respectively.Test
Analyze as follows by the terephthalic acid that obtains among the embodiment 1-4: (1) purity:, introduce μ-bondapak C-18 post and go up the supervision impurity concentration in high pressure liquid chromatography (HPLC) for the terephthalic acid that obtains by PET.(2) median size: introduce sieve analysis and SEM and monitor median size.(3) transparence: terephthalic acid is dissolved in the hydrogen aqueous solutions of potassium, introduces SPECTRONIC 601 (MILTON ROY) spectrometer and monitor transparence at 340nm.(4) colour: introduce DIANO Match Scan II type colorimeter and monitor colour L, a and b.(5) metal content: introduce the metal content that XRF (refraction of X-ray fluorescence) monitors Co, Mn and Fe.Table
| Embodiment | |||||
| ????1 | ????2 | ????3 | ????4 | ||
| The rate of recovery (%) | 98.6 | ???93.6 | ?86.6 | ???99.6 | |
| Purity (%) | 98.5 | ???98.0 | ?99.3 | ???99.1 | |
| Median size (μ m) | 54 | ???66 | ?102 | ????81 | |
| Transparence (%) | 59.8 | ???70.1 | ?55.4 | ???73.8 | |
| Colour | ????L | 97.9 | ???96.6 | ?97.3 | ???98.4 |
| ????a | -0.5 | ???-0.5 | -0.2 | ???-0.3 | |
| ????b | ?1.1 | ???1.7 | ?2.1 | ???1.1 | |
| Metal content (ppm) | ????Co | ?0 | ???0.1 | ?2.2 | ????0 |
| ????Mn | ?0 | ???0 | ?0.1 | ????0 | |
| ????Fe | ?4.6 | ???7.2 | ?16.1 | ????5.3 | |
The result shows in the table, and the purity of the terephthalic acid that obtains in embodiment 1 and 2 is more or less low, and this is because added m-phthalic acid in the production process of PET.It is useful containing m-phthalic acid in the terephthalic acid when the preparation polyester.
Therefore, the terephthalic acid that is reclaimed by the inventive method does not contain any metal, and the purity height is particularly useful when the preparation polyester.
Claims (13)
1. production method of terephthalic acid, wherein polyethylene terephthalate is hydrolyzed with crystallization and obtains terephthalic acid, according to the present invention includes following steps:
(a) under the condition that solvent and treating compound just like water exist, prepare the basic metal/alkaline earth salt of terephthalic acid with the oxyhydroxide hydrolysis PET fragment of basic metal/alkaline-earth metal;
(b) aqueous solution that will be dissolved in the terephthaldehyde's acid alkali metal/alkaline earth salt in the water is separated into solid and liquid; Solid returns described (a) hydrolysing step or discharging, liquid is transported to next adsorption step;
(c) aqueous solution of terephthaldehyde's acid alkali metal/alkaline earth salt is adsorbed, and obtains terephthalic acid with the acid neutralization;
(d) crystallization so that terephthaldehyde's granulates grow up;
(e) and, cooling terephthaldehyde's granulates of growing up under reduced pressure filters and dry.
2. the production method of terephthalic acid of claim 1, the useless fragment of polyethylene terephthalate that wherein is used for step (a) can comprise broken polyester textile, the broken bottle of polyethylene terephthalate, the broken container of polyethylene terephthalate, the broken yarn of polyester that produces in polyethylene terephthalate fragment that the polyethylene terephthalate polymerization production process produces or trevira, yarn and fabric production process.
3. claim 1 or 2 production method of terephthalic acid wherein with respect to the total amount of hydrolyzed solution, add the polyethylene terephthalate fragment of 1-25 weight %.
4. the production method of terephthalic acid of claim 1 wherein with respect to the total amount of hydrolyzed solution, contains basic metal/alkaline earth metal hydroxides of 5-30 weight %.
5. the production method of terephthalic acid of claim 1 wherein with respect to the total amount of hydrolyzed solution, contains the described treating compound of 1-30 weight %.
6. the production method of terephthalic acid of claim 1, wherein said step (a) is at 1-20kg/cm
2Pressure and 30-200 ℃ temperature under carry out.
7. the production method of terephthalic acid of claim 1 wherein in described step (b), with respect to terephthaldehyde's acid alkali metal/alkaline earth salt, is used the water of 0.5-3.0 times of weight.
8. the production method of terephthalic acid of claim 1, wherein said step (d) is carried out in crystallizer, and one to five crystallizer is connected in series, and the temperature of each crystallizer progressively descends 30-50 ℃.
9. the production method of terephthalic acid of claim 8, wherein said crystallizer remains on 2-86kg/cm
2Pressure and 120-300 ℃ temperature under.
10. the production method of terephthalic acid of claim 1, wherein said step (e) is at 0.1-1.0kg/cm
2Pressure and 60-90 ℃ temperature under carry out.
11. the production method of terephthalic acid of claim 1 or 10, wherein in described step (e), the alcohol and water of discharge is returned to described (a) step.
12. the production method of terephthalic acid of claim 1, wherein in described step (e), filtrate is admitted in the electrodialyzer that uses bipolar membrane, to separate bronsted lowry acids and bases bronsted lowry metal/alkaline earth metal hydroxides; Step (c) is returned in acid, and basic metal/alkaline earth metal hydroxides returns step (a).
13. being used for of installing in proper order comprises with lower device from the system of the broken waste material production of polyethylene terephthalate terephthalic acid: hydrolysis device (1), the hydrolysis therein of described PET fragment, preparation terephthaldehyde acid alkali metal/alkaline earth salt; Dissolver (2), terephthaldehyde's acid alkali metal/alkaline earth salt dissolves therein; Centrifugal device (3); Adsorption tower (4); Neutralising arrangement (5) is therein with preparing terephthalic acid with terephthaldehyde's acid alkali metal/alkaline earth salt in the acid; Crystallization apparatus (6), terephthaldehyde's granulates is grown up therein; Refrigerating unit (7); Filtration unit (8), terephthaldehyde's granulates of growing up filters therein; Drying installation (9), filtering terephthalic acid are dry therein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN95198019A CN1113846C (en) | 1995-12-30 | 1995-12-30 | Process for producing terephthalic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN95198019A CN1113846C (en) | 1995-12-30 | 1995-12-30 | Process for producing terephthalic acid |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1209801A true CN1209801A (en) | 1999-03-03 |
| CN1113846C CN1113846C (en) | 2003-07-09 |
Family
ID=5083505
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN95198019A Expired - Fee Related CN1113846C (en) | 1995-12-30 | 1995-12-30 | Process for producing terephthalic acid |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1113846C (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105111063A (en) * | 2015-07-30 | 2015-12-02 | 山西瑞赛格纺织科技有限公司 | Method for preparing terephthalic acid by using waste polyester and cotton fiber |
| CN105960489A (en) * | 2014-01-06 | 2016-09-21 | 瑞来斯实业有限公司 | A process for recovering polyester |
| US11118773B2 (en) | 2016-11-29 | 2021-09-14 | Signify Holding B.V. | Conversion circuit between fluorescent ballast and LED |
| CN114181075A (en) * | 2020-09-14 | 2022-03-15 | 中国石油化工股份有限公司 | Method for producing isophthalic acid by oxidizing m-xylene |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2697839B1 (en) * | 1992-11-09 | 1995-01-13 | Inst Francais Du Petrole | Improved process for recovering alkali metal terephthalate and alkylene glycol from polyalkylene terephthalates. |
| US5395858A (en) * | 1994-04-28 | 1995-03-07 | Partek, Inc. | Process for recycling polyester |
-
1995
- 1995-12-30 CN CN95198019A patent/CN1113846C/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105960489A (en) * | 2014-01-06 | 2016-09-21 | 瑞来斯实业有限公司 | A process for recovering polyester |
| CN105111063A (en) * | 2015-07-30 | 2015-12-02 | 山西瑞赛格纺织科技有限公司 | Method for preparing terephthalic acid by using waste polyester and cotton fiber |
| CN105111063B (en) * | 2015-07-30 | 2017-05-31 | 山西瑞赛格纺织科技有限公司 | A kind of method that terephthalic acid (TPA) is prepared with waste and old polyester fiber |
| US11118773B2 (en) | 2016-11-29 | 2021-09-14 | Signify Holding B.V. | Conversion circuit between fluorescent ballast and LED |
| CN114181075A (en) * | 2020-09-14 | 2022-03-15 | 中国石油化工股份有限公司 | Method for producing isophthalic acid by oxidizing m-xylene |
| CN114181075B (en) * | 2020-09-14 | 2024-01-05 | 中国石油化工股份有限公司 | Method for producing isophthalic acid by oxidizing meta-xylene |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1113846C (en) | 2003-07-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3069917B2 (en) | Method for producing terephthalic acid | |
| EP0873296B1 (en) | Process for manufacturing terephthalic acid | |
| CN104131163A (en) | Regeneration method of P507 organic-phase emulsified mixture for extracting and separating rare earth | |
| CN108002415A (en) | The processing method of the crystal of sodium oxalate is removed in aluminum oxide production process | |
| KR20180011028A (en) | Method of producing a highly-pure aluminum hydroxide | |
| CN102634011B (en) | Poly-p-phenylene terephthamide (PPTA) polymer washing and solvent recovery method | |
| CN1665745A (en) | Production method of phosphoric acid and/or phosphate and products thereof | |
| CN1111682A (en) | Process for treating waste liquid in surface treatment of aluminum materials | |
| CN1113846C (en) | Process for producing terephthalic acid | |
| CN101492399A (en) | Method for preparing methylpropene sodium sulfonate | |
| CN114195315A (en) | Method for combined treatment of acidic and non-acidic copper-containing etching waste liquid, tin stripping waste liquid and copper nitrate waste liquid | |
| CN1067049C (en) | Process for producing terephthalic acid | |
| WO2018052767A1 (en) | Method for producing potassium sulfate from potassium chloride and sulfuric acid | |
| JP3917811B2 (en) | Industrial recovery of terephthalic acid from recovered pulverized polyethylene terephthalate | |
| CN1068866C (en) | Process for producing terephthalic acid | |
| US6310239B1 (en) | Process for manufacturing terephthalic acid | |
| CN1504413A (en) | Reclamation process for waste water of rare earth extraction separation | |
| CN1153764A (en) | Pinene esterifying and saponifying process synthesizing borneol and composite boron-titanium based catalyst | |
| KR100224466B1 (en) | Process for producing terephthalic acid(1) | |
| RU2226174C1 (en) | Method for preparing alumina from bauxite | |
| CN1887452A (en) | Method of recovering and treating gallic acid sludge | |
| CN86104840A (en) | Decomposing phosphate rock by chlorhydric acid liquid-liquid extraction preparation phosphoric acid does not have the discharging of waste liquid circulation technology | |
| CN112707532B (en) | Treatment method of titanium-containing distillation residual liquid, titanium white raw material and application | |
| CN117545718A (en) | Method for recycling fluorine-containing waste residues | |
| CN105731705A (en) | Method for treating p-benzoquinone production wastewater |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |