CN101531594B - 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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- CN101531594B CN101531594B CN2008100846363A CN200810084636A CN101531594B CN 101531594 B CN101531594 B CN 101531594B CN 2008100846363 A CN2008100846363 A CN 2008100846363A CN 200810084636 A CN200810084636 A CN 200810084636A CN 101531594 B CN101531594 B CN 101531594B
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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 polyethyleneterephthalate (PET) is widely used in beverage container, packing film and spins fine industry owing to having good soffening and blowing property.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 like, 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 divalent 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 divalent alcohol carries out alcoholysis reaction, obtains unsaturated polyester resin with the MALEIC ANHYDRIDE copolymerization in the presence of titanium catalyst.But the stripping technique of terepthaloyl moietie (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 divalent 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 in order will the divalent alcohol of surplus to be 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, terepthaloyl moietie and the resulting conjugated polyester resin of other divalent alcohol copolymerizations in the system.The separation method that does not all relate to terepthaloyl moietie 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 terepthaloyl moietie 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 terepthaloyl moietie trapping agent in reaction system, and terepthaloyl moietie 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 generation great amount of wastewater.
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 terepthaloyl moietie that can mix with 2-Ethylhexyl Alcohol, through transferring separator mutually terepthaloyl moietie is separated.Because terepthaloyl moietie 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 through alcoholysis reaction and transesterification reaction in the presence of catalyst simultaneously.In the processing procedure, distilled unit alcohol separates with terepthaloyl moietie 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 terepthaloyl moietie are the mixed solution that mixes; Also can't unit alcohol be separated with terepthaloyl moietie fully through easy still tube device; Get into the participation reaction again of reaction system so that a spot of terepthaloyl moietie refluxes with upper strata liquid 2-Ethylhexyl Alcohol, 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, in Dean & Stark water-and-oil separator, insert in advance under water and the unit alcohol, continue to deviate from divalent 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 property 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 divalent alcohol vibrin through the esterification gained.Better, the polyester raw material among the present invention is polyethyleneterephthalate (PET) resin.
Particularly; The relevant a kind of method for preparing high purity terephthalic acid's diester from polyethyleneterephthalate (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 terepthaloyl moietie that reaction is produced removes and the step of purifying from polyethyleneterephthalate (PET) waste material.
Of the present inventionly prepare in the method for high purity terephthalic acid's ester from polyethyleneterephthalate (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 polyethyleneterephthalate that abbreviates PET as of raw material manufacturing by terephthalic acid and terepthaloyl moietie 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 through terepthaloyl moietie, can solve the convention pet waste and reclaim in the processing procedure problem that the terepthaloyl moietie remaining quantity is higher.In addition, in the inventive method, utilize refractometer to detect the specific refractory power of glycol recovery solution, be able to know 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 through 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 through the processing procedure of simpler and easy, the low energy through easier terepthaloyl moietie 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, terepthaloyl moietie 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 in after state more and explain detailedly.
Starting raw material pet waste used in the present invention means the PET 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 reactor drums assemblings form; If use the situation of a plurality of reactor drums; These reactor drums may not all must be high-pressure reactor, can bear pressure＞5kg/cm as long as wherein carry out the reactor drum of alcoholysis
2Ability get final product; These reactor drums are provided with condensing surface, 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 get into reactor drum and continue reaction, is collected in the storage tank redistillation through the water of collecting subnatant and ethylene glycol solution through the underflow of water-and-oil separator and makes with extra care.
Aliphatics unit alcohol as with the pet waste reaction can be C
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., it is a kind of that these alkanols can use separately, two or more uses also capable of being combined.This alkanol better uses C
7-C
10Alkanol, better be C
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), and more suitable is 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 more suitable is 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 characteristic of the same colour mutually good, that bis--terephthalate's transformation efficiency is high.This catalyst composition is the oxalate compound, like 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 under 230-240 ℃ temperature, carries out.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 more suitable is with 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 possibly cause PET alcoholysis degree not enough; If more than 300 minutes, then possibly cause the terepthaloyl moietie 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 terepthaloyl moietie transesterify in the PET oligomer is come out.Transesterification reaction can be carried out in above-mentioned alcoholysis reaction still, also can in another transesterification reactor, carry out, and can not produce detrimentally affect.For the terepthaloyl moietie 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 reaction kettle 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 terepthaloyl moietie 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, and more suitable is the water and the steam of liquid phase, better is 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, better were 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 possibly take place and make goods purity on the low side in vacuum tightness＜200 mmhg; Then transesterification reaction efficient is on the low side for vacuum tightness＞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 regarded as having reached reaction end.The terepthaloyl moietie 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 the goods that a purity is high, form and aspect are good, acid value is low 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 in thin-film evaporator, evaporate purifying.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.
Characteristic 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, and only these embodiment are merely illustration purpose, but not in order to limit scope of the present invention.
Embodiment 1
In an autoclave that whisking appliance, TM, pressure warning unit, water-and-oil separator, flow director and condensing surface be housed, will drop in the reaction kettle without PET protective membrane (available from the Qimei Electronic Co. Ltd) fragment of cleaning 300 grams, 2-Ethylhexyl Alcohol 712 grams, zinc oxalate 0.6 gram, tetrabutyl titanate ester 0.6 gram.Reaction kettle fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature be warming up to 230 ℃, last gauge pressure is stabilized in 4.5kg/cm
2, through reaction 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 250 grams are imported the reaction kettle 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's aqueous glycol solution is deviate from from the separator bottom; 2-Ethylhexyl Alcohol upper strata liquid then returns reaction kettle 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 by 660 mmhg gradually, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 598 grams (productive rate=98.0%).Thick ester articles via the gel permeation chromatography appearance 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 appearance 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 reaction kettle 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.Reaction kettle fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature 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 reaction kettle 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, and lower floor's aqueous glycol solution is deviate from by the separator bottom, and 2-Ethylhexyl Alcohol upper strata liquid then returns reaction kettle 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 by 660 mmhg gradually, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 602 grams (productive rate=98.6%).Thick ester articles via the gel permeation chromatography appearance 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 reaction kettle 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.Reaction kettle fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature 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
2HCS imports the reaction kettle 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 reaction kettle 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 by 660 mmhg gradually, reclaims excessive isononyl alcohol, thick ester articles 620 grams (productive rate=95.0%).Goods via the gel permeation chromatography appearance 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 reaction kettle without the PET protective membrane fragment of cleaning 300 grams, 2-Ethylhexyl Alcohol 528 grams, tin oxalate 0.6 gram, tetrabutyl titanate ester 0.6 gram.Reaction kettle fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature 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
2HCS imports the reaction kettle 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 reaction kettle 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 by 660 mmhg gradually, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 592 grams (productive rate=97.0%).These goods via the gel permeation chromatography appearance 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 appearance 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 reaction kettle 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.Reaction kettle fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature 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 reaction kettle 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, and lower floor's aqueous glycol solution is deviate from by the separator bottom, and 2-Ethylhexyl Alcohol upper strata liquid then returns reaction kettle 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 by 660 mmhg gradually, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 575 grams (productive rate=94.3%).Filter these thick ester article an acid value 0.10mg KOH/g, form and aspect (platinum-cobalt) 300 goods.These goods via the gel permeation chromatography appearance 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 reaction kettle without the PET protective membrane fragment of cleaning 300 grams, 2-Ethylhexyl Alcohol 650 grams, magnesium acetate 0.3 gram, tetrabutyl titanate ester 0.6 gram.Reaction kettle fully stirs and be forced into gauge pressure under nitrogen gas stream be 2.0kg/cm
2, reaction temperature 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, and pure water 300 gram imports the reaction kettle bottom via the flow director constant speed, and 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 reaction kettle 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 by 660 mmhg gradually, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 570 grams (productive rate=93.4%).Filter these thick ester article an acid value 0.10mg KOH/g, form and aspect (platinum-cobalt) 300 goods.These goods via the gel permeation chromatography appearance 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, drop in the reaction kettle through bottle fragment 300 grams, 2-Ethylhexyl Alcohol 813 grams, zinc acetate 0.3 gram, tetrabutyl titanate ester 0.1 gram of cleaning.Reaction kettle under nitrogen gas stream, fully stirs 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 maintain is at 182 ℃, and the distilled 2-Ethylhexyl Alcohol refluxes through prolong and returns reaction kettle continuation participation reaction, goes through 1.5 hours reaction terminatings.Vacuum tightness is reduced to below 2 mmhg by 610 mmhg gradually, reclaims excessive 2-Ethylhexyl Alcohol, thick ester articles 535 grams (productive rate=87.7%).Filter these thick ester article an acid value 0.10mg KOH/g, form and aspect (platinum-cobalt) 60 goods.These goods via the gel permeation chromatography appearance 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, can obtain purity and be higher than 94.0% as the alcoholysis catalyst; 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 (12)
1. one kind prepares the method for high purity terephthalic acid's diester from the PET waste material, and this method comprises makes pet waste and aliphatic unit alcohol, in the presence of the oxalates catalyst, greater than 2.0kg/cm
2Temperature in 200-250 ℃ under the gauge pressure is carried out alcoholysis reaction, then under the pressure of 170-240 ℃ temperature and 760 to 200mmHg, carries out ester exchange reaction and obtains the bis-terephthalate; Wherein unit alcohol is 2.2～5.0/1 with the PET molecular weight by the mol ratio that the monomer structure unit calculates; And oxalates catalyst use amount is the 0.02-1.0% weight with respect to weight polyester, and wherein this oxalates catalyst is selected from one or more of magnesium oxalate, tin oxalate, zinc oxalate, antimony oxalate and cohort that manganese oxalate is formed.
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; 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.
4. method as claimed in claim 3 is characterized in that, the usage quantity of this cocatalyst is the 0.02-1.0% weight with respect to weight polyester.
5. method as claimed in claim 1 is characterized in that, during carrying out transesterification reaction, imports phase solvent that terepthaloyl moietie is arranged again with the terepthaloyl moietie that will react generation stripping and distillate to a separator together with unit alcohol in system.
6. method as claimed in claim 5 is characterized in that, the phase solvent of this terepthaloyl moietie is water or water vapour.
7. method as claimed in claim 6 is characterized in that, the amount that this water or water vapor import is: X >=40*1/Y,
Wherein X is water or the steam mole number that is added; Y is unit alcohol/PET mol ratio.
8. method as claimed in claim 5 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.
9. method as claimed in claim 8 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.
10. method as claimed in claim 9 is characterized in that this specific refractory power is less than 1.3334/25 ℃.
11. 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 ℃.
12. the method like claim 11 is characterized in that, this distillation is carried out in distillation tower or thin-film evaporator.
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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 |
| US20200010399A1 (en) * | 2017-03-15 | 2020-01-09 | Sabic Global Technologies B.V. | Method of making dialkyl terephthalate 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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| US5319128A (en) * | 1989-03-15 | 1994-06-07 | Synergistics Industries, Ltd. | 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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| US5319128A (en) * | 1989-03-15 | 1994-06-07 | Synergistics Industries, Ltd. | 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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