CN101531594A - Method for preparing high-purity diesters of terephthalate acid from polyethylene terephthalate wastes - Google Patents
Method for preparing high-purity diesters of terephthalate acid from polyethylene terephthalate wastes Download PDFInfo
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Abstract
The invention provides a method for preparing high-purity bis-terephthalate from polyethylene terephthalate wastes. The method comprises the following steps of: using polyethylene terephthalate (PET) waste and aliphatic saturated monoalcohol to pass through the processes of alcoholysis reaction, ester exchange reaction and purification under the existence of oxalate catalyst, thus obtaining the high-purity bis-terephthalate. The prepared bis-terephthalate can be used as a plasticizer. As the PET wastes are used as initiator, the invention can alleviate the negative effects of the PET wastes to the environment, and can reduce the petrochemical material consumption and the preparation cost of the bis-terephthalate.
Description
Technical field
The relevant a kind of polyester waste material from recovery of the present invention prepares bis--terephthalate's method, especially relevant a kind of from the polyester waste material that reclaims, as catalyst, prepare the method for high purity terephthalic acid's two ester plasticizers with oxalate through alcoholysis, transesterification reaction etc.
Background technology
The vibrin of polyethylene terephthalate (PET) is widely used in beverage container, packing film and spins fine industry owing to having good soffening and blowing.Yet use a large amount of waste materials of back generation via beverage container, film and the fiber of processing, or adding the secondary material of generation in man-hour all can bring serious impact to global environment.So various recovery method was arranged in the past as, the recovery method of the recovery of secondary material, the recovery of physics and chemistry.
The recovery of polyester waste material is via the renewable use of physics method, as pulverizing or the fine blend composition that comes as processed goods is spun in extrusion granulation or reel off raw silk from cocoons; But the product through this path institute reclaiming is not high to the value added of industry utilization.Though quite a lot of for polyester waste material chemical recovery Study on Technology in recent years, majority is applied in polyester waste material and dibasic alcohol after the high temperature alcoholysis reaction, secondary pan feeding copolymerization resulting polyester resin.As mentioning among the JP2002-60474A, pet waste after the interpolation dibasic alcohol carries out alcoholysis reaction, obtains unsaturated polyester resin with the MALEIC ANHYDRIDE copolymerization in the presence of titanium catalyst.But the isolation technique of ethylene glycol (EG) among the not mentioned PET in this patent documentation, so that make and be restricted in the practical application because of containing excessive EG in the vibrin composition that is obtained.JP2001-316327A then mentions with pet waste and dibasic alcohol, the compound of titaniferous, tin or zinc as the decomposition reaction catalyst in the presence of, obtain oligomer ester through alcoholysis reaction.In this reaction for the dibasic alcohol of surplus will being extracted, so must use the trichloromethane of severe toxicity; And be restricted firmly in the use partially because of material according to the oligomer ester of this method manufacturing and then with the prepared polyurethane of di-isocyanate reaction.
After the recovery technology of above-mentioned polyester waste material all relates to alcoholysis reaction, ethylene glycol and the resulting conjugated polyester resin of other dibasic alcohol copolymerizations in the system.The separation method that does not all relate to ethylene glycol in the literary composition is so that regenerate still has the character of polyester waste material on rerum natura.It is not satisfactory on the industry purposes after so above-mentioned pet waste is handled again.
In view of the above, propose in addition polyester waste material is added aliphatics unit alcohol reaction regeneration and form bis--terephthalate's method with it subsequently via alcoholysis, this bis--terephthalate is the softening agent of economically valuable.But if be used in the regeneration softening agent and during with industry on the other hand, the ethylene glycol that then faces in the system must remove by pet waste from system, it is good and the softening agent goods of industry utilization can be provided just to obtain purity.Terephthalic acid di-isooctyl (DOTP) is a kind of broad-spectrum non-toxic plasticizer, so because good electric wire and the computer winding displacement of widely applying at electrical equipment of its resistive performance.In addition, because the heat-resistant quality of DOTP is good, processing characteristics is excellent, also be widely used in PVC signature the prolonging film product of processing.The DOTP that sees through the particular process sequence manufacturing via the polyester waste material high method of low-cost economic worth of can yet be regarded as.
So CN1135479A discloses a kind of method that is prepared bis--terephthalate's softening agent by polyester waste material and monohydroxy-alcohol.Above-mentioned raw materials is in the presence of catalyst, and with one section alcoholysis, transesterification reaction method, continuously constant speed adds the ethylene glycol trapping agent in reaction system, and ethylene glycol is separated from reaction system very soon.But when in fact operating, because the fusing point of PET is quite high, if carry out transesterification reaction with the lower monohydroxy-alcohol of boiling point at normal pressure and PET, then the reaction times is tediously long and efficient is poor.In addition, lacking a kind of method of fast monitored reaction end in the reaction and cause its crude ester product acid value and form and aspect higher, is to cause complicated procedures such as processing procedure must neutralize at last, washing, dealcoholysis, dehydration, press filtration, efficient difference and produce a large amount of waste water.
Moreover CN1073164A discloses and a kind ofly prepares the method and apparatus of DOTP with pet waste, and the alcoholysis reaction of PET and 2-Ethylhexyl Alcohol produces the ethylene glycol that can mix with 2-Ethylhexyl Alcohol, through transferring separator mutually ethylene glycol is separated.Because ethylene glycol boiling point (197 ℃) is little with 2-Ethylhexyl Alcohol boiling point (185 ℃) gap, is that the glycol recovery rate is not high through the actually operating result, the transformation efficiency of DOTP is on the low side; And reaction process need be used alkali lye neutralization, washing, dehydration, and processing procedure is loaded down with trivial details and efficient is on the low side.
JP2000-256274A then discloses a kind of method of making lubricating oil and plasticizer with polyester waste material.Pet waste and excessive unit alcohol 2-Ethylhexyl Alcohol carry out simultaneously through alcoholysis reaction and transesterification reaction in the presence of catalyst.In the processing procedure, distilled unit alcohol is separated with ethylene glycol fractionation by distillation pipe, and upper strata liquid 2-Ethylhexyl Alcohol then continues to pass back into reactive system and continues reaction.In fact, 2-Ethylhexyl Alcohol and ethylene glycol are the mixed solution that mixes, also unit alcohol can't be separated fully with ethylene glycol by easy still tube device, so that refluxing with upper strata liquid 2-Ethylhexyl Alcohol, a spot of ethylene glycol enters the participation reaction again of reaction system, cause the reaction times long, bis--terephthalate's transformation efficiency is on the low side.
The US5319128 explanation uses polyester waste material to decompose and bis--terephthalate's method is made in transesterify.Terephthalic polyester resin and unit alcohol carry out alcoholysis and transesterification reaction, at Dean﹠amp; Insert in advance in the Stark water-and-oil separator under water and the unit alcohol, continue to deviate from dibasic alcohol and obtain the bis--terephthalate.Though this method can obtain the diester based article of high ingredient, the huge water-and-oil separator equipment of palpus; And goods must be through water wash procedures; The form and aspect that do not relate to goods in this patent documentation are so commercially practical is not high.
Summary of the invention
The relevant a kind of recovery polyester raw material regeneration application method of the present invention, the polyester raw material among the present invention are aromatic dicarboxylic acid and the dibasic alcohol vibrin through the esterification gained.Better, the polyester raw material among the present invention is polyethylene terephthalate (PET) resin.
Particularly, the relevant a kind of method for preparing high purity terephthalic acid's diester from polyethylene terephthalate (PET) waste material of the present invention, this method comprises makes pet waste and aliphatics unit alcohol, in the presence of the oxalate catalyst, carries out alcoholysis reaction, transesterification reaction.
Of the present inventionly prepare in the method for high purity terephthalic acid's ester, after carrying out transesterification reaction, comprise that again the ethylene glycol that reaction is produced removes and the step of purifying from polyethylene terephthalate (PET) waste material.
Of the present inventionly prepare in the method for high purity terephthalic acid's ester from polyethylene terephthalate (PET) waste material; so-called pet waste means the pet waste of recovery, comprises the protective membrane of bottle fragment, packaging film or the panel of mineral water or soda pop etc., the spinning of fiber industry and the defective material that the processing back produces.And aliphatics unit alcohol is for containing the straight chain of 6-10 carbon atom or the alkanol of difference chain.In the method for the present invention, pet waste reacts with aliphatics unit alcohol after alcoholysis, can obtain bis--terephthalate's main products, and alcoholysis reaction, transesterification reaction are carried out in being characterized as in the presence of specific catalyst of this method.
In view of the above, to be to provide a kind of recovery polyester waste material regenerated method, particularly this vibrin be to be the polyester of the polyethylene terephthalate that abbreviates PET as of raw material manufacturing by terephthalic acid and ethylene glycol to main purpose of the present invention.
According to method of the present invention, this used catalyst can use oxalate, for example magnesium oxalate, tin oxalate, zinc oxalate, antimony oxalate, manganous oxalate etc. separately.Used catalyst in the inventive method except oxalate, can be incorporated other cocatalysts into again according to circumstances, for example for example zinc acetate, tin acetate, magnesium acetate, calcium acetate, manganese acetate, antimony acetate of acetate; Tin compound is dibutyltin diacetate, dibutyl tin laurate, dibutyltin oxide, monobutyltin oxide etc. for example; Titanic acid ester is tetra isopropyl titanate, tetrabutyl titanate ester etc. for example.
According to method of the present invention, the Industrial products that can obtain high purity, low form and aspect are bis--terephthalate's softening agent, terephthalic acid di-isooctyl softening agent especially, and its purity is higher than 94.0%, better is higher than 98.0%; And form and aspect are lower than APHA 25.
According to method of the present invention, remove step by ethylene glycol, can solve known pet waste and reclaim in the processing procedure problem that the ethylene glycol remaining quantity is higher.In addition, in the inventive method, utilize refractometer to detect the specific refractory power of glycol recovery solution, known fast whether reaction is complete, so reaction times that can be most economical obtains highly purified bis--terephthalate.
According to method of the present invention, owing to need not wash, can be by the low processing procedure that pollutes, obtain the Industrial products of tool economic worth via polyester waste material, and can avoid environmental pollution because of reducing a large amount of washess.And in the method for the present invention,, and can reduce the industry production cost by the processing procedure of simpler and easy, the low energy by easier ethylene glycol removal methods.
Embodiment
Main purpose of the present invention be by pet waste make purity be higher than 94.0% and form and aspect be lower than the method for bis--terephthalate's softening agent of APHA 25.Further specify the present invention and improve the bis--terephthalate of pet waste production in the past softening agent, ethylene glycol remains in the higher problem of system, simplifies that prior art must neutralize, washes, dehydration, filtering problem.Its solution is to make pet waste and aliphatics unit alcohol in the presence of specific catalyst, carries out alcoholysis reaction, transesterification reaction, purifying procedure.The inventive method more explains detailedly in aftermentioned.
Starting raw material pet waste used in the present invention means the PET bottle of fragment that mineral water or soda pop bottle produce during fabrication or recovery, packaging film or protective membrane, the spinning of fiber industry and the outer product of specification of producing PET of panel, wherein is preferably bottle fragment and panel protective membrane.This pet waste can without clean or the scrubbing program promptly as the raw material of present method, though impurity can exert an influence to processing procedure and products appearance, can solve this problem via the compensation way of purifying procedure.
The equipment that carries out the inventive method can use single reaction vessel or connect 2 or 3 reactors assemblings form, if use the situation of a plurality of reactors, these reactors may not all must be high-pressure reactor, can bear pressure as long as wherein carry out the reactor of alcoholysis〉5kg/cm
2Ability get final product; These reactors are provided with condenser, measurable control inflow steam or add switching arrangement, the water-and-oil separator of water speed; This water-and-oil separator can make the upper strata liquid in the reaction reflux to enter reactor and continue reaction, and the water through collecting subnatant and ethylene glycol solution are collected in the storage tank redistillation through the underflow of water-and-oil separator and make with extra care.
Can be C as aliphatics unit alcohol with the pet waste reaction
6-C
10Straight chain or difference alkanol, as n-hexyl alcohol, enanthol, heptan-2-alcohol, heptan-3-alcohol, 2-Ethylhexyl Alcohol, n-Octanol, isooctyl alcohol, nonyl alcohol, isononyl alcohol, nonylcarbinol, isodecyl alcohol etc., these alkanols can be used alone, two or more uses also capable of being combined.This alkanol better uses C
7-C
10Alkanol, C more preferably
8-C
10Alkanol.
For impelling transesterification reaction to carry out smoothly, it is excessive that this aliphatics unit alcohol is necessary for respect to the formed reaction mixture of pet waste.This element alcohol is not ear ratio of 2.2-5.0/1 with the ratio of PET (molecular weight calculates in the monomer structure unit), more is suitable for not ear ratio of 2.6-3.5/1.Adding device alcohol of the present invention is regardless of any form in reactive system, can one section interpolation, segmentation add, and is suitable for one section interpolation.
Characteristics of the present invention are to use specific catalyst in the alcoholysis reaction section, the usefulness of this catalyst must can continue to the transesterification reaction section so that processing procedure last; And can access feature of the same colour mutually good, that bis--terephthalate's transformation efficiency is high.This catalyst composition is the oxalate compound, as magnesium oxalate, tin oxalate, zinc oxalate, antimony oxalate, manganous oxalate etc.
Used catalyst composition among the present invention except oxalate, still can contain other cocatalysts, for example acetate such as zinc acetate, tin acetate, magnesium acetate, calcium acetate, manganese acetate, antimony acetate; Tin compounds such as dibutyltin diacetate, dibutyl tin laurate, dibutyltin oxide, monobutyltin oxide; Titanic acid ester cocatalysts such as tetra isopropyl titanate, tetrabutyl titanate ester.Used catalyst among the present invention can use the oxalate compound separately, and oxalate also can use one or more.Moreover, if also with above-mentioned cocatalyst, a kind of or several cocatalysts then also capable of being combined.Among the present invention, the preferable catalyst composition that is combined as oxalate compound and titanic acid ester and usefulness.Its addition out of the ordinary is the 0.02-1.0% weight with respect to weight polyester, and the addition that is more suitable for is a 0.05-0.3% weight.
In the method for the present invention, alcoholysis reaction ties up under the 200-250 ℃ of temperature condition, better at 210-240 ℃, better carries out under 230-240 ℃ temperature.If alcoholysis reaction is lower than 200 ℃ temperature of its lower limit, then alcoholysis speed is crossed slow and incomplete; If alcoholysis reaction is higher than the temperature of 250 ℃ of its upper limits, then alcohol easy inferior solution in unit causes side reaction to produce.The alcoholysis reaction section is pressed greater than 2.0kg/cm at still at least
2Carry out under the gauge pressure, more fortunately 3.0-8.0kg/cm
2Carry out under the gauge pressure; The pressure generation type can the nitrogen pressure or the nature hoisting way of heating, and is suitable in the nitrogen pressure mode.Alcoholysis was carried out about 30-300 of time minute, was preferably 120-180 minute.If the reaction times is less than 30 minutes, then may cause PET alcoholysis degree deficiency; If more than 300 minutes, then may cause the ethylene glycol generation reversed reaction regenerative PET oligomer that produces after the alcoholysis.
Another notable feature of the present invention is in the presence of above-mentioned oxalate catalyst, can promote the transesterification reaction acceleration and ethylene glycol transesterify in the PET oligomer is come out.Transesterification reaction can be carried out in above-mentioned alcoholysis reaction still, also can carry out in another transesterification reactor, and can not produce detrimentally affect.For the ethylene glycol of thorough separating reaction system to improve bis--terephthalate's purity, be provided with a water-and-oil separator in transesterification reactor, be collected in storage tank so that the aqueous glycol solution that continues to deviate from is discharged via the water-and-oil separator bottom, unit alcohol then passes back into reactor by water-and-oil separator upper strata liquid and continues to participate in reaction.The transesterification reaction stage must continue autoreaction system and the middle mutually stripping ethylene glycol of unit alcohol with phase solvent, and more suitable phase solvent is a water.Phase solvent water adds the kenel of system and is regardless of, and can be liquid phase, steam and solid-state, is suitable for the water and the steam of liquid phase, more preferably superheated vapour.The amount that water or water vapor import transesterification reactor is:
X≧40*1/Y
(wherein X is a not ear number of the water that added or steam; Y is a not ear ratio of unit alcohol/PET).
Phase solvent water or water vapor constantly added the time of transesterification reactor from 2-10 hour, were preferably 3-8 hour, more preferably 4-7 hour; Be lower than this time scope and may make transesterification reaction incomplete, cause prepared bis--terephthalate's softening agent purity on the low side; Be higher than this time scope then efficient is on the low side and waste energy.Transesterification reaction temperature is controlled at 170-240 ℃ usually, but under 200-220 ℃ of condition, transesterification reaction efficient is preferable so better.Transesterification reaction pressure can carry out in 760 to 200mmHg pressure, and preferable mode is the decompression reaction.Vacuum tightness is from the 200-700 mmhg, and vacuum tightness is that 400-660 mmhg scope is carried out more fortunately.Reversed reaction may take place and make goods purity on the low side in vacuum tightness＜200 mmhg; Vacuum tightness〉then transesterification reaction efficient is on the low side for 700 mmhg, and the reaction times is long.In order to judge the transesterification reaction terminal point, must be by the ethylene glycol solution of phase solvent stripping by fast monitored, the method for fast monitored transesterification reaction terminal point is for utilizing refractometer among the present invention; When ethylene glycol solution records specific refractory power less than 1.3334/25 ℃ through refractometer, during better less than 1.3330/25 ℃, then be considered as having reached reaction end.The ethylene glycol content of the aqueous glycol solution of specific refractory power in above-mentioned scope is less than 0.1% weight.
Another feature of the present invention is the thick ester articles in above-mentioned transesterification reaction, obtains a purity height, form and aspect are good, acid value is low goods via the purifying processing procedure.This purifying processing procedure can be in above-mentioned transesterification reactor or is connect a distillation tower in addition or evaporate purifying in thin-film evaporator.The purifying processing procedure continues to carry out in vacuum tightness＜2 mmhg and temperature＜240 ℃; If vacuum tightness〉2 mmhg, it is slow then to reclaim speed; Temperature〉240 ℃, then bis--terephthalate Yin Gaowen inferior solution causes goods form and aspect variation, acid value to raise, and processing characteristics is not good.
Feature of the present invention is to use pet waste and unit alcohol, in the presence of a specific catalyst, via alcoholysis reaction, transesterification reaction, purifying procedure, can obtain bis--terephthalate's softening agent goods of a high purity, low form and aspect, low acid value.Moreover present method is because of purified processing procedure, so the pet waste that uses is not defined as the spinning of clean bottle fragment, packaging film, protective membrane or fiber industry, greatly reduces washes and produces.Its result makes the renewable recovery of pet waste, the impact of reaching resource-savingization, green productization and reducing environmental pollution.
The present invention will explain detailedly with the following example, only these embodiment only for the purpose of illustration, but not in order to limit the scope of the invention.
Embodiment 1
In an autoclave that agitator, thermometer, pressure warning unit, water-and-oil separator, flow director and condenser be housed, will drop in the reactor without PET protective membrane (available from Qimei Electronic Co. Ltd) fragment 300 grams of cleaning, 2-Ethylhexyl Alcohol 712 grams, zinc oxalate 0.6 gram, tetrabutyl titanate ester 0.6 gram.Reactor fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature and be warming up to 230 ℃, last gauge pressure is stabilized in 4.5kg/cm
2, slowly pressure release after reacting 2.5 hours, be cooled to 200 ℃.Next imposes vacuum, pressure is reduced to 660 mmhg by normal pressure, pure water 250 grams are imported the reactor bottom via the flow director constant speed, continue to distillate in water-and-oil separator under 180-200 ℃ of condition in temperature of reaction, lower floor deviates from aqueous glycol solution self-separation device bottom; 2-Ethylhexyl Alcohol upper strata liquid then returns reactor through return line and continues to participate in reaction, is 1.3333/25 ℃ with its specific refractory power of refractometer monitoring aqueous glycol solution, and transesterification reaction ends, and deviates from aqueous glycol solution meter 345 grams, course 5.5 hours.Secondly, pressure is reduced to below 2 mmhg gradually by 660 mmhg, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 598 grams (productive rate=98.0%).Thick ester articles via the gel permeation chromatography instrument analyze DOTP (terephthalic acid di-isooctyl)/PET oligomer=98.2/1.8 (area than), so purity is 98.2%.Thick ester articles is to steam under 235 ℃ of conditions through vacuum tightness＜2 mmhg and distillation temperature, and the DOTP of gained is the no stink goods of form and aspect (platinum-cobalt) 8, acid value 0.08mg KOH/g.
Embodiment 2
Except that catalyst tetrabutyl titanate ester replaced with zinc acetate, other conversion units, processing procedure, prescription were as embodiment 1.Thick ester articles 595 grams (productive rate=97.5%); Thick ester articles via the gel permeation chromatography instrument analyze DOTP (terephthalic acid di-isooctyl)/PET oligomer=98.1/1.9 (area than), so purity is 98.1%.Thick ester articles is to steam under 235 ℃ of conditions through vacuum tightness＜2 mmhg and distillation temperature, and the DOTP of gained is the no stink goods of form and aspect (platinum-cobalt) 15, acid value 0.18mg KOH/g.
Embodiment 3
With the conversion unit of embodiment 1, will drop in the reactor without PET protective membrane fragment 300 grams, 2-Ethylhexyl Alcohol 569 grams, zinc oxalate 0.3 gram, tetrabutyl titanate ester 0.6 gram of the same embodiment 1 that cleans.Reactor fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature and be warming up to 230 ℃, last gauge pressure is stabilized in 3.8kg/cm
2, slowly pressure release after 2.5 hours, be cooled to 200 ℃.Next imposes vacuum, pressure is reduced to 660 mmhg by normal pressure, pure water 400 grams import the reactor bottom via the flow director constant speed, temperature of reaction continues to distillate under 200-210 ℃ of condition and is collected in water-and-oil separator, lower floor's aqueous glycol solution is deviate from by the separator bottom, and 2-Ethylhexyl Alcohol upper strata liquid then returns reactor through return line and continues to participate in reaction.With its specific refractory power of refractometer monitoring aqueous glycol solution is 1.3330/25 ℃, and transesterification reaction ends, and deviates from aqueous glycol solution meter 485 grams, course 6.3 hours.Secondly, vacuum tightness is reduced to below 2 mmhg gradually by 660 mmhg, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 602 grams (productive rate=98.6%).Thick ester articles via the gel permeation chromatography instrument analyze DOTP (terephthalic acid di-isooctyl)/PET oligomer=98.8/1.2 (area than), so purity is 98.8%.Thick ester articles is to steam under 235 ℃ of conditions through thin-film evaporator continous vacuum degree＜2 mmhg and distillation temperature, and the DOTP of gained is the goods of the no stink of form and aspect (platinum-cobalt) 20, acid value 0.06mg KOH/g.
Embodiment 4
With the conversion unit of embodiment 1, will drop in the reactor without PET protective membrane fragment 300 grams, isononyl alcohol 675 grams, tin oxalate 0.3 gram, tetrabutyl titanate ester 0.6 gram of the same embodiment 1 that cleans.Reactor fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature and be warming up to 230 ℃, last gauge pressure is stabilized in 3.8kg/cm
2, slowly pressure release after 2.5 hours, be cooled to 200 ℃.Next imposes vacuum, pressure is reduced to 660 mmhg by normal pressure, with 5kg/cm
2High compressed steam imports the reactor bottom via the flowrate control valve constant speed, temperature of reaction continues to distillate under 190-211 ℃ of condition and is collected in the water-and-oil separator, lower floor's aqueous glycol solution is then deviate from via the separator bottom, and isononyl alcohol upper strata liquid then returns reactor through return line and continues to participate in reaction.With its specific refractory power of refractometer monitoring aqueous glycol solution is 1.3331/25 ℃, and transesterification reaction ends, and deviates from aqueous glycol solution meter 489 grams, course 6.3 hours.Secondly, vacuum tightness is reduced to below 2 mmhg gradually by 660 mmhg, reclaims excessive isononyl alcohol, thick ester articles 620 grams (productive rate=95.0%).Goods via the gel permeation chromatography instrument analyze DINTP (terephthalic acid dinonyl)/PET oligomer=98.4/1.6 (area than), so purity is 98.4%.Thick ester articles is to steam under 240 ℃ of conditions through vacuum tightness 1 mmhg and distillation temperature, and the DINTP of gained is the goods of the no stink of form and aspect (platinum-cobalt) 50, acid value 0.30mg KOH/g.
Embodiment 5
With the conversion unit of embodiment 1, will drop in the reactor without PET protective membrane fragment 300 grams of cleaning, 2-Ethylhexyl Alcohol 528 grams, tin oxalate 0.6 gram, tetrabutyl titanate ester 0.6 gram.Reactor fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature and be warming up to 230 ℃, last gauge pressure is stabilized in 3.9kg/cm
2, slowly pressure release after 2.5 hours, be cooled to 200 ℃.Next imposes vacuum, pressure is reduced to 660 mmhg by normal pressure, with 10kg/cm
2High compressed steam imports the reactor bottom via the flowrate control valve constant speed, temperature of reaction continues to distillate under 187-210 ℃ of condition and is collected in the water-and-oil separator, lower floor's aqueous glycol solution is discharged by the separator bottom, and 2-Ethylhexyl Alcohol upper strata liquid then returns reactor through return line and continues to participate in reaction.Continuing to monitor its specific refractory power of discharge aqueous glycol solution with refractometer is 1.3329/25 ℃, and transesterification reaction ends, and deviates from aqueous glycol solution meter 537 grams, course 7.6 hours.Secondly, vacuum tightness is reduced to below 2 mmhg gradually by 660 mmhg, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 592 grams (productive rate=97.0%).These goods via the gel permeation chromatography instrument analyze DOTP (terephthalic acid di-isooctyl)/PET oligomer=98.0/2.0 (area than), so purity is 98.0%.Thick ester articles is to steam under 235 ℃ of conditions through thin-film evaporator continous vacuum degree＜2 mmhg and distillation temperature, and the DOTP of gained is the no stink goods of form and aspect (platinum-cobalt) 8, acid value 0.08mg KOH/g.
Embodiment 6
Except that catalyst tetrabutyl titanate ester did not add, other conversion units, processing procedure, prescription were as embodiment 1.Thick ester articles 591 grams (productive rate=96.9%); Thick ester articles via the gel permeation chromatography instrument analyze DOTP (terephthalic acid di-isooctyl)/PET oligomer=95.0/5.0% (area than), so purity is 95.0%.Thick ester articles is to steam under 235 ℃ of-237 ℃ of conditions through vacuum tightness＜2 mmhg and distillation temperature, and the DOTP of gained is form and aspect (platinum-cobalt) 12, acid value 0.13mg KOH/g, no stink goods.
Comparative example 1
With the conversion unit of embodiment 1, will drop in the reactor without PET protective membrane fragment 300 grams, 2-Ethylhexyl Alcohol 650 grams, zinc acetate 0.3 gram, tetrabutyl titanate ester 0.6 gram of the same embodiment 1 that cleans.Reactor fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature and be warming up to 230 ℃, last gauge pressure is stabilized in 3.9kg/cm
2, slowly pressure release after 2.5 hours, be cooled to 200 ℃.Next imposes vacuum, pressure is reduced to 660 mmhg by normal pressure, pure water 400 grams import the reactor bottom via the flow director constant speed, temperature of reaction continues to distillate under 191-200 ℃ of condition and is collected in water-and-oil separator, lower floor's aqueous glycol solution is deviate from by the separator bottom, and 2-Ethylhexyl Alcohol upper strata liquid then returns reactor through return line and continues to participate in reaction., deviate from aqueous glycol solution meter 425 grams, course 6.3 hours.Secondly, vacuum tightness is reduced to below 2 mmhg gradually by 660 mmhg, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 575 grams (productive rate=94.3%).Filter these thick ester product an acid value 0.10mg KOH/g, form and aspect (platinum-cobalt) 300 goods.These goods via the gel permeation chromatography instrument analyze DOTP (terephthalic acid di-isooctyl)/PET oligomer=90.2/9.8 (area than), so purity is 90.2%.
Comparative example 2
With the conversion unit of embodiment 1, will drop in the reactor without PET protective membrane fragment 300 grams of cleaning, 2-Ethylhexyl Alcohol 650 grams, magnesium acetate 0.3 gram, tetrabutyl titanate ester 0.6 gram.Reactor fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature and be warming up to 230 ℃, last gauge pressure is stabilized in 3.9kg/cm
2, slowly pressure release after 2.5 hours, be cooled to 200 ℃.Next imposes vacuum, pressure is reduced to 660 mmhg by normal pressure, pure water 300 grams import the reactor bottom via the flow director constant speed, temperature of reaction continues to distillate under 185-190 ℃ of condition and is collected in water-and-oil separator, lower floor's aqueous glycol solution is deviate from by the separator bottom, 2-Ethylhexyl Alcohol upper strata liquid then returns reactor through return line to be continued to participate in reaction, deviates from aqueous glycol solution meter 379 grams, course 5.3 hours.Secondly, vacuum tightness is reduced to below 2 mmhg gradually by 660 mmhg, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 570 grams (productive rate=93.4%).Filter these thick ester product an acid value 0.10mg KOH/g, form and aspect (platinum-cobalt) 300 goods.These goods via the gel permeation chromatography instrument analyze DOTP (terephthalic acid di-isooctyl)/PET oligomer=89.5/10.5 (area than), so purity is 89.5%.
Comparative example 3
With the conversion unit of embodiment 1, bottle fragment 300 grams through cleaning, 2-Ethylhexyl Alcohol 813 grams, zinc acetate 0.3 gram, tetrabutyl titanate ester 0.1 gram drop in the reactor.Reactor fully stirs under nitrogen gas stream and gentleness is heated to 190 ℃, during 30 minutes, reaction continued to carry out 5.5 hours.Next imposes vacuum, and pressure is reduced to 610 mmhg by normal pressure, and temperature of reaction maintains 182 ℃, and the distilled 2-Ethylhexyl Alcohol refluxes through prolong and returns reactor continuation participation reaction, goes through 1.5 hours reaction terminatings.Vacuum tightness is reduced to below 2 mmhg gradually by 610 mmhg, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 535 grams (productive rate=87.7%).Filter these thick ester product an acid value 0.10mg KOH/g, form and aspect (platinum-cobalt) 60 goods.These goods via the gel permeation chromatography instrument analyze DOTP (terephthalic acid di-isooctyl)/PET oligomer=76.9/23.1 (area than), so purity is 76.9%.
By the above embodiments and comparative example, can understand according to method of the present invention, utilize oxalate as the alcoholysis catalyst, can obtain purity and be higher than 94.0%, better be higher than 98.0%, form and aspect are lower than APHA 25 and acid value less than the bis--terephthalate of 0.1mgKOH/g, and do not use oxalate of the present invention in the comparative example as the alcoholysis catalyst, the bis--terephthalate's of gained form and aspect are quite high, and purity is relatively low.
Claims (13)
1. one kind prepares the method for high purity terephthalic acid's diester from the polyethylene terephthalate waste material, and this method comprises makes pet waste and aliphatics unit alcohol, in the presence of the oxalate catalyst, greater than 2.0kg/cm
2Temperature in 200-250 ℃ under the gauge pressure is carried out alcoholysis reaction, then carries out transesterification reaction under the pressure of 170-240 ℃ temperature and 760 to 200mmHg and obtains the bis--terephthalate; Wherein unit alcohol is 2.2～5.0/1 with the not ear ratio of PET (molecular weight calculates by the monomer structure unit), and the catalyst usage quantity is the 0.02-1.0% weight with respect to weight polyester.
2. method as claimed in claim 1 is characterized in that, this unit alcohol is for containing the straight chain of 6-10 carbon atom or the alkanol of difference chain.
3. method as claimed in claim 1 is characterized in that this oxalate catalyst is selected from one or more of magnesium oxalate, tin oxalate, zinc oxalate, antimony oxalate and cohort that manganous oxalate is formed.
4. method as claimed in claim 1, it is characterized in that, and then comprising cocatalyst, this cocatalyst is selected from one or more of zinc acetate, tin acetate, magnesium acetate, calcium acetate, manganese acetate, antimony acetate, dibutyltin diacetate, dibutyl tin laurate, dibutyltin oxide, monobutyltin oxide, tetra isopropyl titanate and tetrabutyl titanate cohort that ester is formed.
5. method as claimed in claim 4 is characterized in that, the usage quantity of this cocatalyst is the 0.02-1.0% weight with respect to weight polyester.
6. method as claimed in claim 1 is characterized in that, during carrying out transesterification reaction, imports phase solvent that ethylene glycol is arranged again with the ethylene glycol that will react generation stripping and distillate to a separator together with unit alcohol in system.
7. method as claimed in claim 6 is characterized in that, the phase solvent of this ethylene glycol is water or water vapour.
8. method as claimed in claim 7 is characterized in that, the amount that this water or water vapor import is:
X≧40*1/Y
(wherein X is a not ear number of the water that added or steam; Y is a not ear ratio of unit alcohol/PET).
9. method as claimed in claim 6 is characterized in that, and then in this separator, and the unit alcohol on upper strata is recycled to alcoholysis reaction to be continued to participate in reaction, and the aqueous glycol solution of lower floor gives and reclaiming.
10. method as claimed in claim 9 is characterized in that, comprises that again the ethylene glycol solution to reclaiming carries out detecting refractive index and determines the transesterification reaction terminal point.
11. the method as claim 10 is characterized in that, this specific refractory power is less than 1.3334/25 ℃.
12. method as claimed in claim 1 is characterized in that, after transesterification reaction, comprises that again the bis--terephthalate that makes gained carries out distillation purifying being lower than less than the negative pressure of 2 mmhg and temperature under 240 ℃.
13. the method as claim 12 is characterized in that, this distillation is carried out in distillation tower or thin-film evaporator.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105503605A (en) * | 2015-12-14 | 2016-04-20 | 王林聪 | Method for preparing dimethyl terephthalate from polybutylene terephthalate waste material |
| CN110128271A (en) * | 2019-06-10 | 2019-08-16 | 东莞博斯环保科技有限公司 | A method of dimethyl terephthalate (DMT) is prepared using waste PET polyester |
| CN110229062A (en) * | 2019-06-10 | 2019-09-13 | 东莞博斯环保科技有限公司 | A kind of recovery method of waste PET polyester |
| CN110621650A (en) * | 2017-03-15 | 2019-12-27 | 沙特基础工业全球技术有限公司 | Process for preparing dialkyl terephthalates from terephthalic acid |
| CN114276238A (en) * | 2022-01-07 | 2022-04-05 | 济宁长兴塑料助剂有限公司 | Preparation method of diisooctyl terephthalate |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5101064A (en) * | 1989-03-15 | 1992-03-31 | Synergistics Industries Limited | Production of terephthalate esters by degradative transesterification of scrap or virgin terephthalate polyesters |
| CN1135479A (en) * | 1996-01-31 | 1996-11-13 | 岳阳石油化工总厂研究院 | Method for production of terephthalic acid diester and ethandiol from polyester waste material |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105503605A (en) * | 2015-12-14 | 2016-04-20 | 王林聪 | Method for preparing dimethyl terephthalate from polybutylene terephthalate waste material |
| CN110621650A (en) * | 2017-03-15 | 2019-12-27 | 沙特基础工业全球技术有限公司 | Process for preparing dialkyl terephthalates from terephthalic acid |
| CN110128271A (en) * | 2019-06-10 | 2019-08-16 | 东莞博斯环保科技有限公司 | A method of dimethyl terephthalate (DMT) is prepared using waste PET polyester |
| CN110229062A (en) * | 2019-06-10 | 2019-09-13 | 东莞博斯环保科技有限公司 | A kind of recovery method of waste PET polyester |
| CN114276238A (en) * | 2022-01-07 | 2022-04-05 | 济宁长兴塑料助剂有限公司 | Preparation method of diisooctyl terephthalate |
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