CN117343296A - Method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate - Google Patents
Method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate Download PDFInfo
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- CN117343296A CN117343296A CN202311494664.3A CN202311494664A CN117343296A CN 117343296 A CN117343296 A CN 117343296A CN 202311494664 A CN202311494664 A CN 202311494664A CN 117343296 A CN117343296 A CN 117343296A
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- 238000000034 method Methods 0.000 title claims abstract description 41
- -1 polybutylene Polymers 0.000 title claims abstract description 38
- 229920001748 polybutylene Polymers 0.000 title claims abstract description 35
- 239000003054 catalyst Substances 0.000 claims abstract description 142
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims abstract description 134
- 238000005809 transesterification reaction Methods 0.000 claims abstract description 115
- 239000000463 material Substances 0.000 claims abstract description 60
- 238000006136 alcoholysis reaction Methods 0.000 claims abstract description 57
- 229920000728 polyester Polymers 0.000 claims abstract description 54
- 239000004753 textile Substances 0.000 claims abstract description 53
- 239000002699 waste material Substances 0.000 claims abstract description 49
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims abstract description 46
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims abstract description 25
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 claims abstract description 22
- 239000012535 impurity Substances 0.000 claims abstract description 22
- QPKOBORKPHRBPS-UHFFFAOYSA-N bis(2-hydroxyethyl) terephthalate Chemical compound OCCOC(=O)C1=CC=C(C(=O)OCCO)C=C1 QPKOBORKPHRBPS-UHFFFAOYSA-N 0.000 claims abstract description 19
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 270
- 238000004821 distillation Methods 0.000 claims description 83
- 238000001704 evaporation Methods 0.000 claims description 73
- 238000006243 chemical reaction Methods 0.000 claims description 63
- 230000035484 reaction time Effects 0.000 claims description 45
- 239000000047 product Substances 0.000 claims description 38
- 230000008020 evaporation Effects 0.000 claims description 37
- 238000003860 storage Methods 0.000 claims description 35
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 32
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 30
- 239000006227 byproduct Substances 0.000 claims description 27
- 238000011282 treatment Methods 0.000 claims description 23
- YHWCPXVTRSHPNY-UHFFFAOYSA-N butan-1-olate;titanium(4+) Chemical compound [Ti+4].CCCC[O-].CCCC[O-].CCCC[O-].CCCC[O-] YHWCPXVTRSHPNY-UHFFFAOYSA-N 0.000 claims description 22
- 238000004064 recycling Methods 0.000 claims description 22
- 238000001953 recrystallisation Methods 0.000 claims description 19
- 238000001816 cooling Methods 0.000 claims description 18
- 239000007788 liquid Substances 0.000 claims description 18
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 16
- ZOIORXHNWRGPMV-UHFFFAOYSA-N acetic acid;zinc Chemical compound [Zn].CC(O)=O.CC(O)=O ZOIORXHNWRGPMV-UHFFFAOYSA-N 0.000 claims description 14
- 239000004246 zinc acetate Substances 0.000 claims description 14
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 claims description 10
- VSGNNIFQASZAOI-UHFFFAOYSA-L calcium acetate Chemical compound [Ca+2].CC([O-])=O.CC([O-])=O VSGNNIFQASZAOI-UHFFFAOYSA-L 0.000 claims description 10
- 239000001639 calcium acetate Substances 0.000 claims description 10
- 229960005147 calcium acetate Drugs 0.000 claims description 10
- 235000011092 calcium acetate Nutrition 0.000 claims description 10
- 229940011182 cobalt acetate Drugs 0.000 claims description 10
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 claims description 10
- 238000011084 recovery Methods 0.000 claims description 10
- 238000000926 separation method Methods 0.000 claims description 10
- 238000005266 casting Methods 0.000 claims description 9
- 238000010924 continuous production Methods 0.000 claims description 9
- 238000000280 densification Methods 0.000 claims description 9
- 238000007599 discharging Methods 0.000 claims description 9
- 238000004090 dissolution Methods 0.000 claims description 9
- 238000000895 extractive distillation Methods 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 9
- 239000007787 solid Substances 0.000 claims description 9
- 229940071125 manganese acetate Drugs 0.000 claims description 8
- UOGMEBQRZBEZQT-UHFFFAOYSA-L manganese(2+);diacetate Chemical compound [Mn+2].CC([O-])=O.CC([O-])=O UOGMEBQRZBEZQT-UHFFFAOYSA-L 0.000 claims description 8
- OEOIWYCWCDBOPA-UHFFFAOYSA-N 6-methyl-heptanoic acid Chemical compound CC(C)CCCCC(O)=O OEOIWYCWCDBOPA-UHFFFAOYSA-N 0.000 claims description 7
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 7
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 6
- 229940001593 sodium carbonate Drugs 0.000 claims description 6
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 claims description 6
- 229960000314 zinc acetate Drugs 0.000 claims description 6
- KSCKTBJJRVPGKM-UHFFFAOYSA-N octan-1-olate;titanium(4+) Chemical compound [Ti+4].CCCCCCCC[O-].CCCCCCCC[O-].CCCCCCCC[O-].CCCCCCCC[O-] KSCKTBJJRVPGKM-UHFFFAOYSA-N 0.000 claims description 5
- 229940083608 sodium hydroxide Drugs 0.000 claims description 4
- 239000002783 friction material Substances 0.000 claims description 3
- ITNVWQNWHXEMNS-UHFFFAOYSA-N methanolate;titanium(4+) Chemical compound [Ti+4].[O-]C.[O-]C.[O-]C.[O-]C ITNVWQNWHXEMNS-UHFFFAOYSA-N 0.000 claims description 3
- GFNGXEPRHYGJQP-UHFFFAOYSA-J phthalate;titanium(4+) Chemical compound [Ti+4].[O-]C(=O)C1=CC=CC=C1C([O-])=O.[O-]C(=O)C1=CC=CC=C1C([O-])=O GFNGXEPRHYGJQP-UHFFFAOYSA-J 0.000 claims description 3
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 3
- 238000006482 condensation reaction Methods 0.000 claims description 2
- 229940093956 potassium carbonate Drugs 0.000 claims description 2
- 150000002148 esters Chemical group 0.000 claims 2
- 239000003795 chemical substances by application Substances 0.000 claims 1
- WOZVHXUHUFLZGK-UHFFFAOYSA-N dimethyl terephthalate Chemical compound COC(=O)C1=CC=C(C(=O)OC)C=C1 WOZVHXUHUFLZGK-UHFFFAOYSA-N 0.000 abstract description 258
- 239000002994 raw material Substances 0.000 abstract description 7
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 2
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 229910052799 carbon Inorganic materials 0.000 abstract description 2
- 238000003912 environmental pollution Methods 0.000 abstract description 2
- 239000000835 fiber Substances 0.000 abstract description 2
- 230000008929 regeneration Effects 0.000 abstract description 2
- 238000011069 regeneration method Methods 0.000 abstract description 2
- 238000003786 synthesis reaction Methods 0.000 abstract description 2
- ZZXUZKXVROWEIF-UHFFFAOYSA-N 1,2-butylene carbonate Chemical compound CCC1COC(=O)O1 ZZXUZKXVROWEIF-UHFFFAOYSA-N 0.000 abstract 1
- CBLGXJKSPMNSRJ-UHFFFAOYSA-N 4-(4,4-dihydroxybutoxycarbonyl)benzoic acid Chemical compound OC(O)CCCOC(=O)C1=CC=C(C(O)=O)C=C1 CBLGXJKSPMNSRJ-UHFFFAOYSA-N 0.000 abstract 1
- ZNOHBYNDODQXAO-UHFFFAOYSA-N C1(C2=CC=C(C(=O)OC(C(O)O1)O)C=C2)=O Chemical compound C1(C2=CC=C(C(=O)OC(C(O)O1)O)C=C2)=O ZNOHBYNDODQXAO-UHFFFAOYSA-N 0.000 abstract 1
- 125000004122 cyclic group Chemical group 0.000 abstract 1
- 238000004042 decolorization Methods 0.000 abstract 1
- 238000006068 polycondensation reaction Methods 0.000 abstract 1
- 239000002861 polymer material Substances 0.000 abstract 1
- 238000000746 purification Methods 0.000 abstract 1
- 238000001514 detection method Methods 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- 239000008187 granular material Substances 0.000 description 6
- 230000001788 irregular Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000002689 soil Substances 0.000 description 3
- 238000004043 dyeing Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000001023 inorganic pigment Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 150000003384 small molecules Chemical class 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 229920002988 biodegradable polymer Polymers 0.000 description 1
- 239000004621 biodegradable polymer Substances 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000010436 fluorite Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 238000002074 melt spinning Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000020477 pH reduction Effects 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000012855 volatile organic compound Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/64—Polyesters containing both carboxylic ester groups and carbonate groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
The invention provides a method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate, and relates to the fields of cyclic regeneration of fiber textile materials and synthesis of biodegradable high polymer materials. The invention relates to a method for preparing a primary color biodegradable PBCT by using colored waste polyester textile as a raw material, carrying out glycol alcoholysis to obtain dihydroxyethylene terephthalate (BHET) in the presence of a catalyst, carrying out transesterification on the alcoholysis product to obtain colored crude dimethyl terephthalate (DMT), carrying out impurity removal, purification and decolorization on the colored crude DMT to obtain colorless refined DMT, carrying out transesterification on the colorless refined DMT and 1, 4-Butanediol (BDO) to obtain primary color dihydroxybutyl terephthalate (BHBT), and carrying out polycondensation on the primary color BHBT and methoxy-terminated butylene carbonate (BMBC) prepared by transesterification of dimethyl carbonate (DMC) and 1, 4-Butanediol (BDO). The primary color PBCT obtained by the invention furthest removes dye and impurities in the raw materials in the middle link, and has the quality comparable with that of the primary PBCT; meanwhile, the method is beneficial to saving fossil resources, can reduce environmental pollution and reduce carbon emission.
Description
Technical Field
The invention relates to the technical field of recycling of fiber textile materials and synthesis of biodegradable polymer materials, in particular to a method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate from colored waste polyester textiles.
Background
With the doubling of the global production of polyester textiles, the production of waste polyester textiles reaches 4000 ten thousand tons per year, and most of waste polyester textiles are buried or incinerated as garbage due to the restriction of technology and other factors; because Polyester (PET) is difficult to degrade in soil under natural conditions, landfill treatment not only can pollute groundwater resources, but also can harden soil; and VOCs and the like which are unfavorable for the environment are generated by incineration, and meanwhile, the low-end treatment mode is also extremely wasteful of fossil resources.
Aiming at the treatment technology of colored waste polyester textiles, the colored waste polyester textiles are generally decomposed into small molecules by a chemical method, and then the small molecules are subjected to repolymerization to manufacture new fiber-forming polymers or prepare other chemical raw materials, namely chemical recovery. However, the existence of the dye, the inorganic pigment, other dyeing auxiliary agents and the like in the colored waste polyester textile can influence the chemical recycling, so that the quality of a regenerated product is continuously reduced after each chemical recycling, and the repeated recycling cannot be realized; meanwhile, the chemical recycling of the colored waste polyester textile also has the following problems: if the colored waste polyester textile is not sorted according to color before being treated and is directly recovered chemically, only regenerated polyester with black color can be obtained, thereby greatly restricting the application field and the grade of the final product; if the materials are sorted according to colors before treatment, the problem that the color of the product and the raw materials have great color difference caused by chemical reaction and other factors can also occur in the regeneration process, and secondary dyeing or color compensation, color matching and other treatments are needed in the later use, so that the environment pollution is easy to cause, and the problem that the processing performance is poor because the inorganic pigment, the dye and the gel aggregation particles and other impurities are not removed is also caused.
Disclosure of Invention
In view of the above, the invention provides a method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate from colored waste polyester textiles. The method realizes the resource utilization of the colored waste polyester textile, and the color, performance and other quality indexes of the prepared polybutylene terephthalate-co-butylene carbonate material can be comparable with those of the original PBCT, thereby greatly improving the added value.
The invention is realized by adopting the following technical scheme:
a method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate from colored waste polyester textiles comprises the following steps:
(1) Densification treatment is carried out on colored waste polyester textiles to form agglomerate grains or friction materials; then conveying the materials to an alcoholysis kettle, and carrying out alcoholysis by using glycol;
(2) Conveying the material after alcoholysis to a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted Ethylene Glycol (EG) and recycling the unreacted Ethylene Glycol (EG) to obtain an alcoholysis product;
(3) Carrying out transesterification reaction on the alcoholysis product and methanol in a transesterification reactor I under the action of a catalyst;
(4) Conveying the materials after the transesterification reaction to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted methanol and a gaseous byproduct EG, wherein the methanol and EG are recycled, and collecting a transesterification product, namely colored crude dimethyl terephthalate (DMT);
(5) The colored crude DMT is sent into a reduced pressure distillation kettle, reduced pressure distillation is carried out for 15min to 35min under the conditions that the temperature is 210 ℃ to 240 ℃ and the pressure is 8 KPa to 10KPa, sublimated DMT enters a plurality of sets of parallel collection tanks which can be operated in a switching mode to desublimate, the desublimated colorless refined DMT is discharged after being processed by a rotary scraper, and then the refined DMT is conveyed to a refined DMT storage tank by a screw conveyor; a plurality of collection tanks are switched to realize continuous production of continuous refined DMT; impurities left after reduced pressure distillation continuously enter an impurity collecting tank;
(6) Performing transesterification reaction of colorless refined DMT, 1, 4-Butanediol (BDO) and a catalyst in a transesterification reactor II;
(7) Feeding the material subjected to the transesterification in the step (6) into a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted BDO and gaseous byproduct methanol, wherein BDO and methanol are recycled; collecting the transesterification product, namely the primary color BHBT;
(8) Dimethyl carbonate (DMC), BDO and a transesterification catalyst are subjected to transesterification reaction in a transesterification reactor III, methanol which is a reaction byproduct and DMC which forms an azeotrope with the methanol are extracted through a fractionating column, and the methanol and DMC are sent to an extractive distillation column for separation and recovery;
(9) Feeding the material subjected to transesterification in the step (8) into a flash evaporation device or a reduced pressure distillation device, evaporating unreacted DMC, and collecting BMBC;
(10) BMBC and primary color BHBT are conveyed into a preshrinking reactor, and preshrinking reaction is carried out in the presence of a catalyst;
(11) Conveying the material subjected to the pre-shrinking reaction to a final shrinking reactor for final shrinking reaction to obtain primary color polybutylene terephthalate-co-butylene carbonate (PBCT);
(12) Discharging primary color polybutylene terephthalate-co-butylene carbonate (PBCT) generated after the final shrinkage reaction, and granulating by water-cooling casting belts to obtain primary color PBCT slices; the primary color PBCT slice quality index: the intrinsic viscosity is 1.10dl/g to 1.21dl/g, and the whiteness L value is more than or equal to 83.
Preferably, the alcoholysis process parameters of step (1) are as follows: the temperature is 197-256 ℃, the reaction time is 40-260 min, the mass ratio of the colored waste polyester textile to the glycol is 1:2-8, the catalyst is one or more of zinc acetate, manganese acetate, cobalt acetate, calcium acetate and sodium carbonate, and the addition amount of the catalyst is 0.05-0.5 wt% based on the mass of the colored waste polyester textile.
Preferably, the technological parameters of the transesterification reaction in the step (3) are as follows: the temperature is 55-135 ℃, the reaction time is 30-240 min, the mass ratio of BHET to methanol is 1:2-5, the catalyst is one or more of zinc acetate, manganese acetate, potassium carbonate, cobalt acetate, sodium carbonate, calcium acetate and sodium hydroxide, and the addition amount of the catalyst is 0.05-0.3 wt% based on the mass of BHET.
Preferably, in the step (4), the colored crude DMT enters a reduced pressure distillation kettle, a gas phase pipeline of the reduced pressure distillation kettle is connected with a plurality of collection tanks which are arranged in parallel and can be operated in a switching way, and the collection tanks are provided with rotary scraper devices.
Preferably, the refined DMT storage tank has a heating function, and can heat refined DMT into a liquid state.
Preferably, a plurality of groups of recrystallization tanks which are connected in parallel and can be switched to operate can be arranged in front of the refined DMT storage tank, DMT subjected to reduced pressure distillation sublimation-desublimation treatment is dissolved in hot methanol, the dissolution temperature is 55-135 ℃, then the DMT enters the cooling recrystallization tank to be recrystallized, and high-purity DMT primary color solid is conveyed to the refined DMT storage tank after being treated by a scraper and is heated into liquid.
Preferably, the technological parameters of the transesterification reaction in the step (6) are as follows: the temperature is 155-225 ℃, the reaction time is 120-300 min, the mole ratio of DMT and BDO is 1:3-15, the catalyst is one or more of titanium phthalate, tetraisopropyl titanate, tetramethyl titanate, tetrabutyl titanate, tetraoctyl titanate, alkoxy tin and zinc acetate, the adding amount of the catalyst is 0.01-0.20 wt%, and the mass of the catalyst is calculated by DMT.
Preferably, the technological parameters of the transesterification reaction in the step (8) are as follows: the temperature is 92-160 ℃, and the molar ratio of DMC to BDO is 2.5-8: 1, the catalyst is one or more of zinc acetate, manganese acetate, cobalt acetate, calcium acetate, sodium carbonate, sodium hydroxide and tetrabutyl titanate, and the adding amount of the catalyst is 0.01-0.5 wt% based on the mass of the theoretical BMBC.
Preferably, the technological parameters of the pre-shrinking reaction in the step (10) are as follows: the temperature is 185 ℃ to 235 ℃, and the vacuum residual pressure is 1 KPa to 15KPa; the reaction time is 55-130 min, the catalyst is one or more of tin isooctanoate, tetrabutyl titanate and antimony trioxide, and the addition amount of the catalyst is 0.03-0.10 wt% based on the mass of theoretical PBCT.
Preferably, the process parameters of the final condensation reaction in step (11) are: the temperature is 200-245 ℃, the residual vacuum pressure is 25-130 Pa, and the reaction time is 60-360 min.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention prepares biodegradable primary color polybutylene terephthalate-co-butylene carbonate (PBCT) by taking colored waste Polyester (PET) textiles as raw materials, and the whole process is continuous operation. Universal equipment can be adopted in the process, and the universality and the fusion of industrialized popularization are excellent; meanwhile, the defects that batch quality difference, high running cost and the like are caused by intermittent operation and cannot be solved inherently in intermittent operation are overcome;
2. the method can remove impurities such as gel coagulated particles generated in polymerization and production processing processes in dye, pigment, dye materials and textile raw materials to the greatest extent through separation processes such as continuous flash evaporation, continuous reduced pressure distillation and optional recrystallization and the like which can be operated in units, so as to obtain regenerated raw materials with high purity, and realize recycling of colored waste polyester textiles for multiple times or even unlimited times; and the quality of the primary color PBCT is comparable with that of the primary PBCT; meanwhile, the method is beneficial to saving fossil resources, reducing environmental pollution and reducing carbon emission.
3. Compared with commercial polybutylene terephthalate-co-adipate (PBAT), the primary PBCT prepared by the invention does not generate acidic substances in the degradation process, and does not cause hardening and acidification of soil when being applied to agricultural mulching films; and the melt spinning has good spinnability and wider application.
Detailed Description
The invention is further illustrated below with reference to examples.
Example 1
A method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate from colored waste polyester textiles comprises the following specific steps:
(1) Densification treatment is carried out on colored waste polyester textiles to form agglomerated granules; then conveying the materials to an alcoholysis kettle, and adding Ethylene Glycol (EG) and a catalyst according to a proportion for alcoholysis; wherein the size of the agglomerate grains is irregular sphere with the maximum diameter not exceeding 3 cm. Wherein the alcoholysis reaction temperature is 256 ℃, the reaction time is 40min, the mass ratio of the colored waste polyester textile to the glycol is 1:8, the catalyst is sodium carbonate, and the addition amount of the catalyst is 0.05wt% based on the mass of the colored waste polyester textile.
(2) Conveying the material after alcoholysis to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted glycol and recycling the unreacted glycol to obtain an alcoholysis product;
(3) Carrying out transesterification reaction on the alcoholysis product and methanol under the action of a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 135 ℃, the reaction time is 60min, the mass ratio of BHET to methanol is 1:5, the catalyst is sodium hydroxide, and the addition amount of the catalyst is 0.3wt% based on the mass of BHET.
(4) Conveying the materials after the transesterification reaction to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted methanol and gaseous byproducts, recycling methanol and ethylene glycol, and collecting the transesterification product, namely colored crude DMT; wherein the gas phase pipeline of the reduced pressure distillation kettle is connected with a plurality of sets of collection tanks which are arranged in parallel and can be switched to operate, and the collection tanks are provided with rotary scraper devices.
(5) The colored crude DMT enters a reduced pressure distillation kettle, is subjected to reduced pressure distillation for 35min under the condition of the temperature of 235 ℃ and the pressure of 10KPa, sublimated colorless refined DMT enters a plurality of sets of parallel collection tanks which can be operated in a switching mode, is sublimated, is discharged after being processed by a rotary scraper, and is conveyed to a refined DMT storage tank by a screw conveyor; a plurality of collection tanks are switched to realize continuous production of continuous refined DMT; impurities left after reduced pressure distillation continuously enter an impurity collecting tank; wherein the colorless refined DMT storage tank has a heating function, and can heat the colorless refined DMT into a liquid state.
And a plurality of groups of recrystallization tanks which are connected in parallel and can be switched to operate can be arranged in front of the refined DMT storage tank, DMT subjected to reduced pressure distillation sublimation-desublimation treatment is dissolved in hot methanol, the dissolution temperature is 130 ℃, then the DMT enters the cooling recrystallization tank to be recrystallized, and high-purity DMT primary color solids are conveyed to the refined DMT storage tank after being treated by a scraper and are heated to be liquid.
(6) Transesterification of refined DMT with 1, 4-Butanediol (BDO) and a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 225 ℃, the reaction time is 120min, the molar ratio of DMT to BDO is 1:8, the catalyst is tetrabutyl titanate and zinc acetate, and the adding amount of the catalyst is 0.2 weight percent, calculated by the mass of DMT.
(7) Feeding the material subjected to the transesterification in the step (6) into a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted BDO and gaseous byproducts, wherein BDO and methanol are recycled; collecting the transesterification product, namely the primary color BHBT;
(8) Dimethyl carbonate (DMC), BDO and a transesterification catalyst are subjected to transesterification reaction, methanol which is a reaction byproduct and DMC which forms an azeotrope with the methanol are extracted through a fractionating column, and the methanol and DMC which form an azeotrope with the methanol are sent to an extractive distillation column for separation and recovery; wherein the technological parameters of the transesterification reaction are as follows: the temperature was 160℃and the molar ratio of DMC to BDO was 8:1, the catalyst is tetrabutyl titanate and cobalt acetate, and the addition amount of the catalyst is 0.5wt% based on the mass of theoretical BMBC.
(9) Feeding the material subjected to transesterification in the step (8) into a flash evaporation device or a reduced pressure distillation device, evaporating DMC, and collecting BMBC;
(10) BMBC and BHBT are conveyed into a preshrinking reactor, and preshrinking reaction is carried out in the presence of a catalyst; wherein the technological parameters of the pre-shrinking reaction are as follows: the temperature is 235 ℃, and the vacuum residual pressure is 2KPa; the reaction time is 55min, the catalyst is tin isooctanoate and tetrabutyl titanate (tin isooctanoate: tetrabutyl titanate is 1:3), the adding amount of the catalyst is 0.1wt%, based on the mass of theoretical PBCT;
(11) Conveying the material subjected to the pre-shrinking reaction to a final shrinking reactor for final shrinking reaction to obtain primary color polybutylene terephthalate-co-butylene carbonate (PBCT); wherein the technological parameters of the final shrinkage reaction are as follows: the temperature is 245 ℃, the vacuum residual pressure is 25Pa, and the reaction time is 60min.
(12) Discharging primary color polybutylene terephthalate-co-butylene carbonate (PBCT) generated after the final shrinkage reaction, and granulating by water-cooling casting belts to obtain primary color PBCT slices;
through detection, the quality index of the primary color PBCT slice is as follows: the intrinsic viscosity was 1.21dl/g, and the whiteness L value was 83.
Example 2
A method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate comprises the following specific steps:
(1) Densification treatment is carried out on the colored waste polyester textile to obtain friction material; then the materials are conveyed to an alcoholysis kettle, and glycol (EG) and a catalyst are added according to a certain proportion for alcoholysis; wherein the alcoholysis reaction temperature is 200 ℃, the reaction time is 260min, the mass ratio of the colored waste polyester textile to the glycol is 1:6, the catalyst is calcium acetate and sodium carbonate, and the addition amount of the catalyst is 0.5wt% based on the mass of the colored waste polyester textile.
(2) Conveying the material after alcoholysis to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted EG and recycling the EG to obtain an alcoholysis product;
(3) Carrying out transesterification reaction on the alcoholysis product and methanol under the action of a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 85 ℃, the reaction time is 210min, the mass ratio of BHET to methanol is 1:2, the catalyst is sodium hydroxide, and the adding amount of the catalyst is 0.1wt% based on the mass of BHET.
(4) Conveying the materials after the transesterification reaction to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted methanol and gaseous byproducts, recycling methanol and ethylene glycol, and collecting the transesterification product, namely colored crude DMT; wherein the gas phase pipeline of the reduced pressure distillation kettle is connected with a plurality of sets of collection tanks which are arranged in parallel and can be switched to operate, and the collection tanks are provided with rotary scraper devices.
(5) The colored crude DMT enters a reduced pressure distillation kettle, is subjected to reduced pressure distillation for 20min under the condition of 240 ℃ and 8KPa, sublimated primary color refined DMT enters a plurality of sets of parallel collection tanks which can be operated in a switching mode, is discharged after being processed by a rotary scraper, and is conveyed to a refined DMT storage tank by a screw conveyor; a plurality of collection tanks are switched to realize continuous production of continuous refined DMT; impurities left after reduced pressure distillation continuously enter an impurity collecting tank; wherein the refined DMT storage tank has a heating function and can heat refined DMT into liquid state.
And a plurality of groups of recrystallization tanks which are connected in parallel and can be switched to operate can be arranged in front of the refined DMT storage tank, DMT subjected to reduced pressure distillation sublimation-desublimation treatment is dissolved in hot methanol, the dissolution temperature is 120 ℃, then the DMT enters the cooling recrystallization tank to be recrystallized, and high-purity DMT primary color solids are conveyed to the refined DMT storage tank after being treated by a scraper and are heated into liquid.
(6) Transesterification of refined DMT with 1, 4-Butanediol (BDO) and a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 185 ℃, the reaction time is 300min, the molar ratio of DMT to BDO is 1:10, the catalyst is tetramethyl titanate, and the adding amount of the catalyst is 0.08wt%, based on the mass of DMT.
(7) Feeding the material subjected to the transesterification in the step (6) into a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted BDO and gaseous byproducts, wherein BDO and methanol are recycled; collecting the transesterification product, namely the primary color BHBT;
(8) Dimethyl carbonate (DMC), BDO and a transesterification catalyst are subjected to transesterification reaction, methanol which is a reaction byproduct and DMC which forms an azeotrope with the methanol are extracted through a fractionating column, and the methanol and DMC which form an azeotrope with the methanol are sent to an extractive distillation column for separation and recovery; wherein the technological parameters of the transesterification reaction are as follows: the temperature was 92℃and the molar ratio of DMC to BDO was 3:1, the catalyst is zinc acetate, and the adding amount of the catalyst is 0.3wt% based on the mass of the theoretical BMBC.
(9) Feeding the material subjected to transesterification in the step (8) into a flash evaporation device or a reduced pressure distillation device, evaporating DMC, and collecting BMBC;
(10) BMBC and BHBT are conveyed into a preshrinking reactor, and preshrinking reaction is carried out in the presence of a catalyst; wherein the technological parameters of the pre-shrinking reaction are as follows: the temperature is 185 ℃, and the vacuum residual pressure is 10KPa; the reaction time is 130min, the catalyst is tetrabutyl titanate, the adding amount of the catalyst is 0.03 weight percent, and the catalyst is calculated by the mass of theoretical PBCT generation
(11) Conveying the material subjected to the pre-shrinking reaction to a final shrinking reactor for final shrinking reaction to obtain primary color polybutylene terephthalate-co-butylene carbonate (PBCT); wherein the technological parameters of the final shrinkage reaction are as follows: the temperature is 215 ℃, the vacuum residual pressure is 130Pa, and the reaction time is 340min.
(12) Discharging primary color polybutylene terephthalate-co-butylene carbonate (PBCT) generated after the final shrinkage reaction, and granulating by water-cooling casting belts to obtain primary color PBCT slices;
through detection, the quality index of the primary color PBCT slice is as follows: the intrinsic viscosity was 1.15dl/g and the whiteness L value was 88.
Example 3
A method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate from colored waste polyester textiles comprises the following specific steps:
(1) Densification treatment is carried out on colored waste polyester textiles to form agglomerated granules; then conveying the materials to an alcoholysis kettle, and adding Ethylene Glycol (EG) and a catalyst according to a proportion for alcoholysis; wherein the size of the agglomerate grains is irregular sphere with the maximum diameter not exceeding 3 cm. Wherein the alcoholysis reaction temperature is 200 ℃, the reaction time is 240min, the mass ratio of the colored waste polyester textile to the glycol is 1:6, the catalyst is sodium carbonate and manganese acetate, and the addition amount of the catalyst is 0.5wt% based on the mass of the colored waste polyester textile.
(2) Conveying the material after alcoholysis to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted glycol and recycling the unreacted glycol to obtain an alcoholysis product;
(3) Carrying out transesterification reaction on the alcoholysis product and methanol under the action of a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 85 ℃, the reaction time is 210min, the mass ratio of BHET to methanol is 1:2, the catalyst is sodium carbonate and sodium hydroxide, and the addition amount of the catalyst is 0.1wt%, calculated by the mass of BHET.
(4) Conveying the materials after the transesterification reaction to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted methanol and gaseous byproducts, recycling methanol and ethylene glycol, and collecting the transesterification product, namely colored crude DMT; wherein the gas phase pipeline of the reduced pressure distillation kettle is connected with a plurality of sets of collection tanks which are arranged in parallel and can be switched to operate, and the collection tanks are provided with rotary scraper devices.
(5) The colored crude DMT enters a reduced pressure distillation kettle, is subjected to reduced pressure distillation for 15min under the condition of the temperature of 240 ℃ and the pressure of 10KPa, sublimated colorless refined DMT enters a plurality of sets of parallel collection tanks which can be operated in a switching mode, is sublimated, is discharged after being processed by a rotary scraper, and is conveyed to a refined DMT storage tank by a screw conveyor; a plurality of collection tanks are switched to realize continuous production of continuous refined DMT; impurities left after reduced pressure distillation continuously enter an impurity collecting tank; wherein the colorless refined DMT storage tank has a heating function, and can heat the colorless refined DMT into a liquid state.
And a plurality of groups of recrystallization tanks which are connected in parallel and can be switched to operate can be arranged in front of the refined DMT storage tank, DMT subjected to reduced pressure distillation sublimation-desublimation treatment is dissolved in hot methanol, the dissolution temperature is 100 ℃, then the DMT enters the cooling recrystallization tank to be recrystallized, and high-purity DMT primary color solids are conveyed to the refined DMT storage tank after being treated by a scraper and are heated into liquid.
(6) Transesterification of refined DMT with 1, 4-Butanediol (BDO) and a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 185 ℃, the reaction time is 300min, the molar ratio of DMT to BDO is 1:10, the catalyst is tetraoctyl titanate, and the adding amount of the catalyst is 0.12wt%, based on the mass of DMT.
(7) Feeding the material subjected to the transesterification in the step (6) into a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted BDO and gaseous byproducts, wherein BDO and methanol are recycled; collecting the transesterification product, namely the primary color BHBT;
(8) Dimethyl carbonate (DMC), BDO and a transesterification catalyst are subjected to transesterification reaction, methanol which is a reaction byproduct and DMC which forms an azeotrope with the methanol are extracted through a fractionating column, and the methanol and DMC which form an azeotrope with the methanol are sent to an extractive distillation column for separation and recovery; wherein the technological parameters of the transesterification reaction are as follows: the temperature was 110 ℃, and the molar ratio of DMC to BDO was 3:1, the catalyst is tetrabutyl titanate and zinc acetate, and the addition amount of the catalyst is 0.05wt% based on the mass of the theoretical BMBC.
(9) Feeding the material subjected to transesterification in the step (8) into a flash evaporation device or a reduced pressure distillation device, evaporating DMC, and collecting BMBC;
(10) BMBC and BHBT are conveyed into a preshrinking reactor, and preshrinking reaction is carried out in the presence of a catalyst; wherein the technological parameters of the pre-shrinking reaction are as follows: the temperature is 185 ℃, and the vacuum residual pressure is 10KPa; the reaction time is 130min, the catalyst is tetrabutyl titanate, and the addition amount of the catalyst is 0.03 weight percent based on the mass of theoretical PBCT;
(11) Conveying the material subjected to the pre-shrinking reaction to a final shrinking reactor for final shrinking reaction to obtain primary color polybutylene terephthalate-co-butylene carbonate (PBCT); wherein the technological parameters of the final shrinkage reaction are as follows: the temperature is 215 ℃, the vacuum residual pressure is 130Pa, and the reaction time is 340min.
(12) Discharging primary color polybutylene terephthalate-co-butylene carbonate (PBCT) generated after the final shrinkage reaction, and granulating by water-cooling casting belts to obtain primary color PBCT slices;
through detection, the quality index of the primary color PBCT slice is as follows: the intrinsic viscosity was 1.13dl/g and the whiteness L value was 89.
Example 4
A method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate from colored waste polyester textiles comprises the following specific steps:
(1) Densification treatment is carried out on colored waste polyester textiles to form agglomerated granules; then conveying the materials to an alcoholysis kettle, and adding Ethylene Glycol (EG) and a catalyst according to a proportion for alcoholysis; wherein the size of the agglomerate grains is irregular sphere with the maximum diameter not exceeding 3 cm. Wherein the alcoholysis reaction temperature is 220 ℃, the reaction time is 130min, the mass ratio of the colored waste polyester textile to the glycol is 1:4, the catalyst is sodium carbonate and zinc acetate, and the addition amount of the catalyst is 0.1wt% based on the mass of the colored waste polyester textile.
(2) Conveying the material after alcoholysis to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted glycol and recycling the unreacted glycol to obtain an alcoholysis product;
(3) Carrying out transesterification reaction on the alcoholysis product and methanol under the action of a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 70 ℃, the reaction time is 210min, the mass ratio of BHET to methanol is 1:3, the catalyst is sodium carbonate and cobalt acetate, and the addition amount of the catalyst is 0.15wt%, calculated by the mass of BHET.
(4) Conveying the materials after the transesterification reaction to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted methanol and gaseous byproducts, recycling methanol and ethylene glycol, and collecting the transesterification product, namely colored crude DMT; wherein the gas phase pipeline of the reduced pressure distillation kettle is connected with a plurality of sets of collection tanks which are arranged in parallel and can be switched to operate, and the collection tanks are provided with rotary scraper devices.
(5) The colored crude DMT enters a reduced pressure distillation kettle, is subjected to reduced pressure distillation for 25min under the condition of 230 ℃ and 8KPa, sublimated colorless refined DMT enters a plurality of sets of parallel collection tanks which can be operated in a switching mode, is sublimated, is discharged after being processed by a rotary scraper, and is conveyed to a refined DMT storage tank by a screw conveyor; a plurality of collection tanks are switched to realize continuous production of continuous refined DMT; impurities left after reduced pressure distillation continuously enter an impurity collecting tank; wherein the colorless refined DMT storage tank has a heating function, and can heat the colorless refined DMT into a liquid state.
And a plurality of groups of recrystallization tanks which are connected in parallel and can be switched to operate can be arranged in front of the refined DMT storage tank, DMT subjected to reduced pressure distillation sublimation-desublimation treatment is dissolved in hot methanol, the dissolution temperature is 100 ℃, then the DMT enters the cooling recrystallization tank to be recrystallized, and high-purity DMT primary color solids are conveyed to the refined DMT storage tank after being treated by a scraper and are heated into liquid.
(6) Transesterification of refined DMT with 1, 4-Butanediol (BDO) and a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 175 ℃, the reaction time is 250min, the mole ratio of DMT and BDO is 1:8, the catalyst is tetraoctyl titanate and zinc acetate, and the adding amount of the catalyst is 0.15wt%, based on the mass of DMT.
(7) Feeding the material subjected to the transesterification in the step (6) into a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted BDO and gaseous byproducts, wherein BDO and methanol are recycled; collecting the transesterification product, namely the primary color BHBT;
(8) Dimethyl carbonate (DMC), BDO and a transesterification catalyst are subjected to transesterification reaction, methanol which is a reaction byproduct and DMC which forms an azeotrope with the methanol are extracted through a fractionating column, and the methanol and DMC which form an azeotrope with the methanol are sent to an extractive distillation column for separation and recovery; wherein the technological parameters of the transesterification reaction are as follows: the temperature was 110℃and the molar ratio of DMC to BDO was 5:1, the catalyst is tetrabutyl titanate and calcium acetate, and the addition amount of the catalyst is 0.2 weight percent based on the mass of the theoretical BMBC.
(9) Feeding the material subjected to transesterification in the step (8) into a flash evaporation device or a reduced pressure distillation device, evaporating DMC, and collecting BMBC;
(10) BMBC and BHBT are conveyed into a preshrinking reactor, and preshrinking reaction is carried out in the presence of a catalyst; wherein the technological parameters of the pre-shrinking reaction are as follows: the temperature is 195 ℃, and the vacuum residual pressure is 10KPa; the reaction time is 100min, the catalyst is tetrabutyl titanate and antimonous oxide, the adding amount of the catalyst is 0.06wt%, and the catalyst accounts for the mass of theoretical PBCT;
(11) Conveying the material subjected to the pre-shrinking reaction to a final shrinking reactor for final shrinking reaction to obtain primary color polybutylene terephthalate-co-butylene carbonate (PBCT); wherein the technological parameters of the final shrinkage reaction are as follows: the temperature is 220 ℃, the vacuum residual pressure is 130Pa, and the reaction time is 310min.
(12) Discharging primary color polybutylene terephthalate-co-butylene carbonate (PBCT) generated after the final shrinkage reaction, and granulating by water-cooling casting belts to obtain primary color PBCT slices;
through detection, the quality index of the primary color PBCT slice is as follows: the intrinsic viscosity was 1.17dl/g and the whiteness L value was 88.
Example 5
A method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate from colored waste polyester textiles comprises the following specific steps:
(1) Densification treatment is carried out on colored waste polyester textiles to form agglomerated granules; then conveying the materials to an alcoholysis kettle, and adding Ethylene Glycol (EG) and a catalyst according to a proportion for alcoholysis; wherein the size of the agglomerate grains is irregular sphere with the maximum diameter not exceeding 3 cm. Wherein the alcoholysis reaction temperature is 220 ℃, the reaction time is 180min, the mass ratio of the colored waste polyester textile to the glycol is 1:4, the catalyst is sodium carbonate and cobalt acetate, and the addition amount of the catalyst is 0.1wt% based on the mass of the colored waste polyester textile.
(2) Conveying the material after alcoholysis to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted glycol and recycling the unreacted glycol to obtain an alcoholysis product;
(3) Carrying out transesterification reaction on the alcoholysis product and methanol under the action of a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 70 ℃, the reaction time is 210min, the mass ratio of BHET to methanol is 1:3, the catalyst is sodium carbonate and zinc acetate, and the addition amount of the catalyst is 0.15wt%, calculated by the mass of BHET.
(4) Conveying the materials after the transesterification reaction to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted methanol and gaseous byproducts, recycling methanol and ethylene glycol, and collecting the transesterification product, namely colored crude DMT; wherein the gas phase pipeline of the reduced pressure distillation kettle is connected with a plurality of sets of collection tanks which are arranged in parallel and can be switched to operate, and the collection tanks are provided with rotary scraper devices.
(5) The colored crude DMT enters a reduced pressure distillation kettle, is subjected to reduced pressure distillation for 25min under the conditions of 220 ℃ and 10KPa, sublimated colorless refined DMT enters a plurality of sets of parallel collection tanks which can be operated in a switching mode, is sublimated, is discharged after being processed by a rotary scraper, and is conveyed to a refined DMT storage tank by a screw conveyor; a plurality of collection tanks are switched to realize continuous production of continuous refined DMT; impurities left after reduced pressure distillation continuously enter an impurity collecting tank; wherein the colorless refined DMT storage tank has a heating function, and can heat the colorless refined DMT into a liquid state.
And a plurality of groups of recrystallization tanks which are connected in parallel and can be switched to operate can be arranged in front of the refined DMT storage tank, DMT subjected to reduced pressure distillation sublimation-desublimation treatment is dissolved in hot methanol, the dissolution temperature is 80 ℃, then the DMT enters the cooling recrystallization tank to be recrystallized, and high-purity DMT primary color solids are conveyed to the refined DMT storage tank after being treated by a scraper and are heated into liquid.
(6) Transesterification of refined DMT with 1, 4-Butanediol (BDO) and a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 175 ℃, the reaction time is 250min, the mole ratio of DMT and BDO is 1:8, the catalyst is tetrabutyl titanate and alkoxy tin, and the adding amount of the catalyst is 0.13 weight percent based on the mass of DMT.
(7) Feeding the material subjected to the transesterification in the step (6) into a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted BDO and gaseous byproducts, wherein BDO and methanol are recycled; collecting the transesterification product, namely the primary color BHBT;
(8) Dimethyl carbonate (DMC), BDO and a transesterification catalyst are subjected to transesterification reaction, methanol which is a reaction byproduct and DMC which forms an azeotrope with the methanol are extracted through a fractionating column, and the methanol and DMC which form an azeotrope with the methanol are sent to an extractive distillation column for separation and recovery; wherein the technological parameters of the transesterification reaction are as follows: the temperature was 125℃and the molar ratio of DMC to BDO was 5:1, the catalyst is tetrabutyl titanate and manganese acetate, and the addition amount of the catalyst is 0.25wt% based on the mass of theoretical BMBC.
(9) Feeding the material subjected to transesterification in the step (8) into a flash evaporation device or a reduced pressure distillation device, evaporating DMC, and collecting BMBC;
(10) BMBC and BHBT are conveyed into a preshrinking reactor, and preshrinking reaction is carried out in the presence of a catalyst; wherein the technological parameters of the pre-shrinking reaction are as follows: the temperature is 195 ℃, and the vacuum residual pressure is 5KPa; the reaction time is 100min, the catalyst is tetrabutyl titanate, tin isooctanoate and antimony trioxide, the adding amount of the catalyst is 0.06wt%, and the catalyst is calculated by the mass of the theoretical PBCT;
(11) Conveying the material subjected to the pre-shrinking reaction to a final shrinking reactor for final shrinking reaction to obtain primary color polybutylene terephthalate-co-butylene carbonate (PBCT); wherein the technological parameters of the final shrinkage reaction are as follows: the temperature is 220 ℃, the vacuum residual pressure is 120Pa, and the reaction time is 310min.
(12) Discharging primary color polybutylene terephthalate-co-butylene carbonate (PBCT) generated after the final shrinkage reaction, and granulating by water-cooling casting belts to obtain primary color PBCT slices;
through detection, the quality index of the primary color PBCT slice is as follows: the intrinsic viscosity was 1.19dl/g and the whiteness L value was 89.
Example 6
A method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate from colored waste polyester textiles comprises the following specific steps:
(1) Densification treatment is carried out on colored waste polyester textiles to form agglomerated granules; then conveying the materials to an alcoholysis kettle, and adding Ethylene Glycol (EG) and a catalyst according to a proportion for alcoholysis; wherein the size of the agglomerate grains is irregular sphere with the maximum diameter not exceeding 3 cm. Wherein the alcoholysis reaction temperature is 240 ℃, the reaction time is 170min, the mass ratio of the colored waste polyester textile to the glycol is 1:3, the catalyst is sodium carbonate and calcium acetate, and the addition amount of the catalyst is 0.3wt% based on the mass of the colored waste polyester textile.
(2) Conveying the material after alcoholysis to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted glycol and recycling the unreacted glycol to obtain an alcoholysis product;
(3) Carrying out transesterification reaction on the alcoholysis product and methanol under the action of a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 65 ℃, the reaction time is 210min, the mass ratio of BHET to methanol is 1:4, the catalyst is potassium carbonate and sodium hydroxide, and the addition amount of the catalyst is 0.2wt%, calculated by the mass of BHET.
(4) Conveying the materials after the transesterification reaction to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted methanol and gaseous byproducts, recycling methanol and ethylene glycol, and collecting the transesterification product, namely colored crude DMT; wherein the gas phase pipeline of the reduced pressure distillation kettle is connected with a plurality of sets of collection tanks which are arranged in parallel and can be switched to operate, and the collection tanks are provided with rotary scraper devices.
(5) The colored crude DMT enters a reduced pressure distillation kettle, is subjected to reduced pressure distillation for 30min under the conditions of the temperature of 215 ℃ and the pressure of 8KPa, sublimated colorless refined DMT enters a plurality of sets of parallel collection tanks which can be operated in a switching mode, is sublimated, is discharged after being processed by a rotary scraper, and is conveyed to a refined DMT storage tank by a screw conveyor; a plurality of collection tanks are switched to realize continuous production of continuous refined DMT; impurities left after reduced pressure distillation continuously enter an impurity collecting tank; wherein the colorless refined DMT storage tank has a heating function, and can heat the colorless refined DMT into a liquid state.
And a plurality of groups of recrystallization tanks which are connected in parallel and can be switched to operate can be arranged in front of the refined DMT storage tank, DMT subjected to reduced pressure distillation sublimation-desublimation treatment is dissolved in hot methanol, the dissolution temperature is 70 ℃, then the DMT enters the cooling recrystallization tank to be recrystallized, and high-purity DMT primary color solids are conveyed to the refined DMT storage tank after being treated by a scraper and are heated to be liquid.
(6) Transesterification of refined DMT with 1, 4-Butanediol (BDO) and a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 160 ℃, the reaction time is 200min, the molar ratio of DMT to BDO is 1:6, the catalyst is tetraoctyl titanate and titanate fluorite, and the adding amount of the catalyst is 0.1wt%, based on the mass of DMT.
(7) Feeding the material subjected to the transesterification in the step (6) into a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted BDO and gaseous byproducts, wherein BDO and methanol are recycled; collecting the transesterification product, namely the primary color BHBT;
(8) Dimethyl carbonate (DMC), BDO and a transesterification catalyst are subjected to transesterification reaction, methanol which is a reaction byproduct and DMC which forms an azeotrope with the methanol are extracted through a fractionating column, and the methanol and DMC which form an azeotrope with the methanol are sent to an extractive distillation column for separation and recovery; wherein the technological parameters of the transesterification reaction are as follows: the temperature was 140℃and the molar ratio of DMC to BDO was 6:1, the catalyst is tetrabutyl titanate and sodium hydroxide, and the adding amount of the catalyst is 0.1 weight percent based on the mass of the theoretical BMBC.
(9) Feeding the material subjected to transesterification in the step (8) into a flash evaporation device or a reduced pressure distillation device, evaporating DMC, and collecting BMBC;
(10) BMBC and BHBT are conveyed into a preshrinking reactor, and preshrinking reaction is carried out in the presence of a catalyst; wherein the technological parameters of the pre-shrinking reaction are as follows: the temperature is 205 ℃, and the vacuum residual pressure is 5KPa; the reaction time is 70min, the catalyst is tetrabutyl titanate, tin isooctanoate and antimony trioxide, the adding amount of the catalyst is 0.08wt%, and the catalyst is calculated by the mass of the theoretical PBCT;
(11) Conveying the material subjected to the pre-shrinking reaction to a final shrinking reactor for final shrinking reaction to obtain primary color polybutylene terephthalate-co-butylene carbonate (PBCT); wherein the technological parameters of the final shrinkage reaction are as follows: the temperature was 230℃and the residual vacuum pressure was 120Pa, and the reaction time was 320min.
(12) Discharging primary color polybutylene terephthalate-co-butylene carbonate (PBCT) generated after the final shrinkage reaction, and granulating by water-cooling casting belts to obtain primary color PBCT slices;
through detection, the quality index of the primary color PBCT slice is as follows: the intrinsic viscosity was 1.16dl/g and the whiteness L value was 86.
Example 7
A method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate from colored waste polyester textiles comprises the following specific steps:
(1) Densification treatment is carried out on colored waste polyester textiles to form agglomerated granules; then conveying the materials to an alcoholysis kettle, and adding Ethylene Glycol (EG) and a catalyst according to a proportion for alcoholysis; wherein the size of the agglomerate grains is irregular sphere with the maximum diameter not exceeding 3 cm. Wherein the alcoholysis reaction temperature is 240 ℃, the reaction time is 200min, the mass ratio of the colored waste polyester textile to the glycol is 1:3, the catalyst is sodium carbonate and cobalt acetate, and the addition amount of the catalyst is 0.3wt% based on the mass of the colored waste polyester textile.
(2) Conveying the material after alcoholysis to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted glycol and recycling the unreacted glycol to obtain an alcoholysis product;
(3) Carrying out transesterification reaction on the alcoholysis product and methanol under the action of a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 55 ℃, the reaction time is 210min, the mass ratio of BHET to methanol is 1:4, the catalyst is calcium acetate and sodium hydroxide, and the addition amount of the catalyst is 0.2wt%, calculated by the mass of BHET.
(4) Conveying the materials after the transesterification reaction to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted methanol and gaseous byproducts, recycling methanol and ethylene glycol, and collecting the transesterification product, namely colored crude DMT; wherein the gas phase pipeline of the reduced pressure distillation kettle is connected with a plurality of sets of collection tanks which are arranged in parallel and can be switched to operate, and the collection tanks are provided with rotary scraper devices.
(5) The colored crude DMT enters a reduced pressure distillation kettle, is subjected to reduced pressure distillation for 30min under the condition of the temperature of 210 ℃ and the pressure of 10KPa, sublimated colorless refined DMT enters a plurality of sets of parallel collection tanks which can be operated in a switching mode, is sublimated, is discharged after being processed by a rotary scraper, and is conveyed to a refined DMT storage tank by a screw conveyor; a plurality of collection tanks are switched to realize continuous production of continuous refined DMT; impurities left after reduced pressure distillation continuously enter an impurity collecting tank; wherein the colorless refined DMT storage tank has a heating function, and can heat the colorless refined DMT into a liquid state.
And a plurality of groups of recrystallization tanks which are connected in parallel and can be switched to operate can be arranged in front of the refined DMT storage tank, DMT subjected to reduced pressure distillation sublimation-desublimation treatment is dissolved in hot methanol, the dissolution temperature is 55 ℃, then the DMT enters the cooling recrystallization tank to be recrystallized, and high-purity DMT primary color solids are conveyed to the refined DMT storage tank after being treated by a scraper and are heated into liquid.
(6) Transesterification of refined DMT with 1, 4-Butanediol (BDO) and a catalyst; wherein the technological parameters of the transesterification reaction are as follows: the temperature is 155 ℃, the reaction time is 200min, the mole ratio of DMT and BDO is 1:6, the catalyst is titanium phthalate and tetraisopropyl titanate, and the adding amount of the catalyst is 0.1wt%, calculated by the mass of DMT.
(7) Feeding the material subjected to the transesterification in the step (6) into a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted BDO and gaseous byproducts, wherein BDO and methanol are recycled; collecting the transesterification product, namely the primary color BHBT;
(8) Dimethyl carbonate (DMC), BDO and a transesterification catalyst are subjected to transesterification reaction, methanol which is a reaction byproduct and DMC which forms an azeotrope with the methanol are extracted through a fractionating column, and the methanol and DMC which form an azeotrope with the methanol are sent to an extractive distillation column for separation and recovery; wherein the technological parameters of the transesterification reaction are as follows: the temperature was 155℃and the molar ratio of DMC to BDO was 6:1, the catalyst is tetrabutyl titanate, and the adding amount of the catalyst is 0.4 weight percent based on the mass of the theoretical BMBC.
(9) Feeding the material subjected to transesterification in the step (8) into a flash evaporation device or a reduced pressure distillation device, evaporating DMC, and collecting BMBC;
(10) BMBC and BHBT are conveyed into a preshrinking reactor, and preshrinking reaction is carried out in the presence of a catalyst; wherein the technological parameters of the pre-shrinking reaction are as follows: the temperature is 205 ℃, and the vacuum residual pressure is 10KPa; the reaction time is 70min, the catalyst is tetrabutyl titanate and tin isooctanoate, and the addition amount of the catalyst is 0.08wt% based on the mass of theoretical PBCT;
(11) Conveying the material subjected to the pre-shrinking reaction to a final shrinking reactor for final shrinking reaction to obtain primary color polybutylene terephthalate-co-butylene carbonate (PBCT); wherein the technological parameters of the final shrinkage reaction are as follows: the temperature was 230℃and the residual vacuum pressure was 110Pa, and the reaction time was 300min.
(12) Discharging primary color polybutylene terephthalate-co-butylene carbonate (PBCT) generated after the final shrinkage reaction, and granulating by water-cooling casting belts to obtain primary color PBCT slices;
through detection, the quality index of the primary color PBCT slice is as follows: the intrinsic viscosity was 1.21dl/g and the whiteness L value was 87.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (10)
1. The method for preparing primary color biodegradable polybutylene terephthalate-co-butylene carbonate by using colored waste polyester textiles is characterized by comprising the following steps of:
(1) Densification treatment is carried out on colored waste polyester textiles to form agglomerate grains or friction materials; then the materials are conveyed to an alcoholysis kettle, and simultaneously alcoholysis agent glycol (EG) and catalyst are added for alcoholysis, wherein the molar ratio of colored waste polyester textiles to EG is 1:2-8;
(2) Conveying the material after alcoholysis to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted EG and recycling the EG to obtain an alcoholysis product;
(3) The alcoholysis product, methanol and a catalyst are proportionally conveyed to an ester exchange reactor I, and an ester exchange reaction is carried out under the action of the catalyst;
(4) Conveying the materials after the transesterification reaction to a flash evaporation device or a reduced pressure distillation device, evaporating unreacted methanol and a gaseous byproduct EG, wherein the methanol and EG are recycled, and collecting the transesterification product, namely colored crude DMT;
(5) The colored crude DMT enters a reduced pressure distillation kettle, is subjected to reduced pressure distillation for 15-35 min under the conditions of the temperature of 210-240 ℃ and the pressure of 8-10 KPa, sublimates and enters a plurality of sets of parallel collecting tanks which can be operated in a switching way, and the sublimated colorless refined DMT is discharged after being processed by a rotary scraper and is conveyed to a refined DMT storage tank by a screw conveyor; a plurality of collection tanks are switched to realize continuous production of continuous refined DMT; impurities left after reduced pressure distillation continuously enter an impurity collecting tank;
(6) Performing transesterification reaction on colorless refined DMT, 1, 4-Butanediol (BDO) and a catalyst in a transesterification reactor II according to a certain proportion;
(7) Feeding the material subjected to the transesterification in the step (6) into a flash evaporation device or a reduced pressure distillation device, and evaporating unreacted BDO and gaseous byproduct methanol, wherein BDO and methanol are recycled; collecting the transesterification product, namely the primary color BHBT;
(8) Dimethyl carbonate (DMC), BDO and a transesterification catalyst are subjected to transesterification reaction in a transesterification reactor III according to a certain proportion, methanol which is a reaction byproduct and DMC which forms an azeotrope with the methanol are extracted through a fractionating column, and the methanol and DMC are sent to an extractive distillation column for separation and recovery;
(9) Feeding the material subjected to transesterification in the step (8) into a flash evaporation device or a reduced pressure distillation device, evaporating DMC, and collecting BMBC;
(10) The BMBC and the primary color BHBT are proportionally conveyed into a preshrinking reactor, and preshrinking reaction is carried out in the presence of a catalyst;
(11) Conveying the material after the pre-shrinking reaction to a final shrinking reactor for final shrinking reaction to obtain primary color regenerated polybutylene terephthalate-co-butylene carbonate (PBCT);
(12) Discharging primary color polybutylene terephthalate-co-butylene carbonate (PBCT) generated after the final shrinkage reaction, and granulating by water-cooling casting belts to obtain primary color PBCT slices; the primary color PBCT slice quality index: the intrinsic viscosity is 1.10dl/g to 1.21dl/g, and the whiteness L value is more than or equal to 83.
2. The method of claim 1, wherein the alcoholysis process parameters of step (1) are as follows: the temperature is 197-256 ℃, the reaction time is 40-260 min, the mass ratio of the colored waste polyester textile to the glycol is 1:2-8, the catalyst is one or more of zinc acetate, manganese acetate, cobalt acetate, calcium acetate and sodium carbonate, and the addition amount of the catalyst is 0.05-0.5 wt% based on the mass of the colored waste polyester textile.
3. The method of claim 1, wherein the process parameters of the transesterification reaction of step (3) are: the temperature is 55-135 ℃, the reaction time is 30-240 min, the mass ratio of BHET to methanol is 1:2-5, the catalyst is one or more of zinc acetate, manganese acetate, potassium carbonate, cobalt acetate, sodium carbonate, calcium acetate and sodium hydroxide, and the addition amount of the catalyst is 0.05-0.3 wt% based on the mass of BHET.
4. The method of claim 1, wherein step (4) is carried out by introducing the colored crude DMT into a reduced pressure distillation still having a gas phase conduit connected to a plurality of parallel arranged, switchably operable collection vessels configured with rotary doctor blade devices.
5. The method of claim 1, wherein the fine DMT tank has a heating function to heat the fine DMT to a liquid state.
6. The method according to claim 1, wherein a plurality of groups of recrystallization tanks which are connected in parallel and can be switched to operate are arranged in front of the refined DMT storage tank, DMT subjected to reduced pressure distillation sublimation-desublimation treatment is dissolved in hot methanol at a dissolution temperature of 55-135 ℃, then the DMT is sent to a cooling recrystallization tank to be recrystallized, and high-purity DMT primary color solids are sent to the refined DMT storage tank after being treated by a scraper and heated to be liquid.
7. The method of claim 1, wherein the process parameters of the transesterification reaction of step (6) are: the temperature is 155-225 ℃, the reaction time is 120-300 min, the mole ratio of DMT and BDO is 1:3-15, the catalyst is one or more of titanium phthalate, tetraisopropyl titanate, tetramethyl titanate, tetrabutyl titanate, tetraoctyl titanate, alkoxy tin and zinc acetate, the adding amount of the catalyst is 0.01-0.20 wt%, and the mass of the catalyst is calculated by DMT.
8. The method of claim 1, wherein the process parameters of the transesterification reaction of step (8) are: the temperature is 92-160 ℃, and the molar ratio of DMC to BDO is 2.5-8: 1, the catalyst is one or more of zinc acetate, manganese acetate, cobalt acetate, calcium acetate, sodium carbonate, sodium hydroxide and tetrabutyl titanate, and the adding amount of the catalyst is 0.01-0.5 wt% based on the mass of the theoretical BMBC.
9. The method of claim 1, wherein the process parameters of the pre-shrinking reaction of step (10) are: the temperature is 185 ℃ to 235 ℃, and the vacuum residual pressure is 1 KPa to 15KPa; the reaction time is 55-130 min, the catalyst is one or more of tin isooctanoate, tetrabutyl titanate and antimony trioxide, and the addition amount of the catalyst is 0.03-0.10 wt% based on the mass of theoretical PBCT.
10. The method of claim 1, wherein the process parameters of the final condensation reaction of step (11) are: the temperature is 200-245 ℃, the residual vacuum pressure is 25-130 Pa, and the reaction time is 60-360 min.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1771223A (en) * | 2003-04-09 | 2006-05-10 | 巴斯福股份公司 | Cooling and purification of gas streams |
| CN116023640A (en) * | 2022-11-30 | 2023-04-28 | 北京服装学院 | Method for preparing biodegradable polybutylene terephthalate-co-butylene carbonate from waste polyester textiles |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1771223A (en) * | 2003-04-09 | 2006-05-10 | 巴斯福股份公司 | Cooling and purification of gas streams |
| CN116023640A (en) * | 2022-11-30 | 2023-04-28 | 北京服装学院 | Method for preparing biodegradable polybutylene terephthalate-co-butylene carbonate from waste polyester textiles |
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| Title |
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| 赵国樑: "我国废旧纺织品综合再利用技术现状及展望", 《北京服装学院学报》, vol. 39, no. 1, 30 March 2019 (2019-03-30), pages 94 - 100 * |
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