JP4171823B2 - Depolymerization of polyester using supercritical carbon dioxide and process for producing polyester from depolymerization product - Google Patents
Depolymerization of polyester using supercritical carbon dioxide and process for producing polyester from depolymerization product Download PDFInfo
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- JP4171823B2 JP4171823B2 JP2002193114A JP2002193114A JP4171823B2 JP 4171823 B2 JP4171823 B2 JP 4171823B2 JP 2002193114 A JP2002193114 A JP 2002193114A JP 2002193114 A JP2002193114 A JP 2002193114A JP 4171823 B2 JP4171823 B2 JP 4171823B2
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- Prior art keywords
- polyester
- depolymerization
- carbon dioxide
- reaction
- lipase
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- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 title claims description 78
- 229910002092 carbon dioxide Inorganic materials 0.000 title claims description 44
- 239000001569 carbon dioxide Substances 0.000 title claims description 44
- 238000000034 method Methods 0.000 title claims description 39
- 229920000728 polyester Polymers 0.000 title claims description 30
- 239000004367 Lipase Substances 0.000 claims description 38
- 125000004122 cyclic group Chemical group 0.000 claims description 28
- 238000006116 polymerization reaction Methods 0.000 claims description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 108090001060 Lipase Proteins 0.000 claims description 16
- 102000004882 Lipase Human genes 0.000 claims description 16
- 235000019421 lipase Nutrition 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 9
- 239000002685 polymerization catalyst Substances 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 description 52
- 239000000047 product Substances 0.000 description 32
- 229920000642 polymer Polymers 0.000 description 30
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 16
- 239000007789 gas Substances 0.000 description 16
- 239000012530 fluid Substances 0.000 description 14
- 239000000126 substance Substances 0.000 description 14
- 238000004064 recycling Methods 0.000 description 13
- 125000004432 carbon atom Chemical group C* 0.000 description 10
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical class OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 description 10
- 238000012691 depolymerization reaction Methods 0.000 description 10
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 9
- 108090000790 Enzymes Proteins 0.000 description 9
- 102000004190 Enzymes Human genes 0.000 description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 9
- 125000002947 alkylene group Chemical group 0.000 description 7
- 239000007810 chemical reaction solvent Substances 0.000 description 7
- 230000007423 decrease Effects 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000000178 monomer Substances 0.000 description 7
- 239000002904 solvent Substances 0.000 description 7
- WHBMMWSBFZVSSR-UHFFFAOYSA-N 3-hydroxybutyric acid Chemical compound CC(O)CC(O)=O WHBMMWSBFZVSSR-UHFFFAOYSA-N 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 108010084311 Novozyme 435 Proteins 0.000 description 6
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 6
- 229910052799 carbon Inorganic materials 0.000 description 6
- OEERIBPGRSLGEK-UHFFFAOYSA-N carbon dioxide;methanol Chemical compound OC.O=C=O OEERIBPGRSLGEK-UHFFFAOYSA-N 0.000 description 6
- 229920001577 copolymer Polymers 0.000 description 6
- 238000000354 decomposition reaction Methods 0.000 description 6
- 239000000706 filtrate Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- 239000003960 organic solvent Substances 0.000 description 6
- -1 polybutylene succinate Polymers 0.000 description 6
- 229910001220 stainless steel Inorganic materials 0.000 description 6
- 239000010935 stainless steel Substances 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 239000000539 dimer Substances 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- 102000004157 Hydrolases Human genes 0.000 description 4
- 108090000604 Hydrolases Proteins 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000005265 energy consumption Methods 0.000 description 4
- 229920001610 polycaprolactone Polymers 0.000 description 4
- 239000012429 reaction media Substances 0.000 description 4
- PAPBSGBWRJIAAV-UHFFFAOYSA-N ε-Caprolactone Chemical compound O=C1CCCCCO1 PAPBSGBWRJIAAV-UHFFFAOYSA-N 0.000 description 4
- AXKZIDYFAMKWSA-UHFFFAOYSA-N 1,6-dioxacyclododecane-7,12-dione Chemical compound O=C1CCCCC(=O)OCCCCO1 AXKZIDYFAMKWSA-UHFFFAOYSA-N 0.000 description 3
- 238000005160 1H NMR spectroscopy Methods 0.000 description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 239000012141 concentrate Substances 0.000 description 3
- 239000012043 crude product Substances 0.000 description 3
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 3
- 150000002596 lactones Chemical class 0.000 description 3
- 238000001840 matrix-assisted laser desorption--ionisation time-of-flight mass spectrometry Methods 0.000 description 3
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 3
- 238000005580 one pot reaction Methods 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 239000004632 polycaprolactone Substances 0.000 description 3
- 239000002861 polymer material Substances 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 3
- ZMKVBUOZONDYBW-UHFFFAOYSA-N 1,6-dioxecane-2,5-dione Chemical compound O=C1CCC(=O)OCCCCO1 ZMKVBUOZONDYBW-UHFFFAOYSA-N 0.000 description 2
- NUTDOUGNQAMWBU-UHFFFAOYSA-N 1,8-dioxacyclotetradecane-2,9-dione Chemical compound O=C1CCCCCOC(=O)CCCCCO1 NUTDOUGNQAMWBU-UHFFFAOYSA-N 0.000 description 2
- XPDWGBQVDMORPB-UHFFFAOYSA-N Fluoroform Chemical compound FC(F)F XPDWGBQVDMORPB-UHFFFAOYSA-N 0.000 description 2
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 2
- 241001661345 Moesziomyces antarcticus Species 0.000 description 2
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 125000000217 alkyl group Chemical group 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- RYYVLZVUVIJVGH-UHFFFAOYSA-N caffeine Chemical compound CN1C(=O)N(C)C(=O)C2=C1N=CN2C RYYVLZVUVIJVGH-UHFFFAOYSA-N 0.000 description 2
- 238000004440 column chromatography Methods 0.000 description 2
- 238000012790 confirmation Methods 0.000 description 2
- 230000002255 enzymatic effect Effects 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 238000001955 polymer synthesis method Methods 0.000 description 2
- 230000000379 polymerizing effect Effects 0.000 description 2
- 229920005862 polyol Polymers 0.000 description 2
- 150000003077 polyols Chemical class 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 125000001424 substituent group Chemical group 0.000 description 2
- QIVUCLWGARAQIO-OLIXTKCUSA-N (3s)-n-[(3s,5s,6r)-6-methyl-2-oxo-1-(2,2,2-trifluoroethyl)-5-(2,3,6-trifluorophenyl)piperidin-3-yl]-2-oxospiro[1h-pyrrolo[2,3-b]pyridine-3,6'-5,7-dihydrocyclopenta[b]pyridine]-3'-carboxamide Chemical compound C1([C@H]2[C@H](N(C(=O)[C@@H](NC(=O)C=3C=C4C[C@]5(CC4=NC=3)C3=CC=CN=C3NC5=O)C2)CC(F)(F)F)C)=C(F)C=CC(F)=C1F QIVUCLWGARAQIO-OLIXTKCUSA-N 0.000 description 1
- UJGHGRGFKZWGMS-UHFFFAOYSA-N 1,3-dioxan-2-one Chemical compound O=C1OCCCO1.O=C1OCCCO1 UJGHGRGFKZWGMS-UHFFFAOYSA-N 0.000 description 1
- CKXDKAOBYWWYEK-UHFFFAOYSA-N 1,6-dioxecane-2,5-dione;hexanedioic acid Chemical compound OC(=O)CCCCC(O)=O.O=C1CCC(=O)OCCCCO1 CKXDKAOBYWWYEK-UHFFFAOYSA-N 0.000 description 1
- 238000001644 13C nuclear magnetic resonance spectroscopy Methods 0.000 description 1
- XEZNGIUYQVAUSS-UHFFFAOYSA-N 18-crown-6 Chemical compound C1COCCOCCOCCOCCOCCO1 XEZNGIUYQVAUSS-UHFFFAOYSA-N 0.000 description 1
- LHASZEBEQGPCFM-CJFMBICVSA-N 2-amino-4-[(1r)-1-[[(6r)-6-[(5-chloro-2-methoxyphenyl)methyl]-7-oxo-3-(phenoxyamino)-5,6-dihydro-2h-1,4-diazepine-1-carbonyl]amino]propyl]benzoic acid Chemical compound C([C@@H]1CNC(CN(C1=O)C(=O)N[C@H](CC)C=1C=C(N)C(C(O)=O)=CC=1)=NOC=1C=CC=CC=1)C1=CC(Cl)=CC=C1OC LHASZEBEQGPCFM-CJFMBICVSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 108010093096 Immobilized Enzymes Proteins 0.000 description 1
- LPHGQDQBBGAPDZ-UHFFFAOYSA-N Isocaffeine Natural products CN1C(=O)N(C)C(=O)C2=C1N(C)C=N2 LPHGQDQBBGAPDZ-UHFFFAOYSA-N 0.000 description 1
- 241001122767 Theaceae Species 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 125000004450 alkenylene group Chemical group 0.000 description 1
- 125000004419 alkynylene group Chemical group 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- ALRHLSYJTWAHJZ-UHFFFAOYSA-N beta-hydroxy propionic acid Natural products OCCC(O)=O ALRHLSYJTWAHJZ-UHFFFAOYSA-N 0.000 description 1
- REKYPYSUBKSCAT-UHFFFAOYSA-N beta-hydroxyvaleric acid Natural products CCC(O)CC(O)=O REKYPYSUBKSCAT-UHFFFAOYSA-N 0.000 description 1
- 238000012662 bulk polymerization Methods 0.000 description 1
- 229960001948 caffeine Drugs 0.000 description 1
- VJEONQKOZGKCAK-UHFFFAOYSA-N caffeine Natural products CN1C(=O)N(C)C(=O)C2=C1C=CN2C VJEONQKOZGKCAK-UHFFFAOYSA-N 0.000 description 1
- 229910002090 carbon oxide Inorganic materials 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000002144 chemical decomposition reaction Methods 0.000 description 1
- KYKAJFCTULSVSH-UHFFFAOYSA-N chloro(fluoro)methane Chemical compound F[C]Cl KYKAJFCTULSVSH-UHFFFAOYSA-N 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000000921 elemental analysis Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000006206 glycosylation reaction Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 150000001261 hydroxy acids Chemical class 0.000 description 1
- 238000002329 infrared spectrum Methods 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 1
- AYOOGWWGECJQPI-NSHDSACASA-N n-[(1s)-1-(5-fluoropyrimidin-2-yl)ethyl]-3-(3-propan-2-yloxy-1h-pyrazol-5-yl)imidazo[4,5-b]pyridin-5-amine Chemical compound N1C(OC(C)C)=CC(N2C3=NC(N[C@@H](C)C=4N=CC(F)=CN=4)=CC=C3N=C2)=N1 AYOOGWWGECJQPI-NSHDSACASA-N 0.000 description 1
- XULSCZPZVQIMFM-IPZQJPLYSA-N odevixibat Chemical compound C12=CC(SC)=C(OCC(=O)N[C@@H](C(=O)N[C@@H](CC)C(O)=O)C=3C=CC(O)=CC=3)C=C2S(=O)(=O)NC(CCCC)(CCCC)CN1C1=CC=CC=C1 XULSCZPZVQIMFM-IPZQJPLYSA-N 0.000 description 1
- 229920000739 poly(3-hydroxycarboxylic acid) polymer Polymers 0.000 description 1
- 229920001281 polyalkylene Polymers 0.000 description 1
- 229920002961 polybutylene succinate Polymers 0.000 description 1
- 239000004631 polybutylene succinate Substances 0.000 description 1
- 238000012667 polymer degradation Methods 0.000 description 1
- 229940096992 potassium oleate Drugs 0.000 description 1
- MLICVSDCCDDWMD-KVVVOXFISA-M potassium;(z)-octadec-9-enoate Chemical compound [K+].CCCCCCCC\C=C/CCCCCCCC([O-])=O MLICVSDCCDDWMD-KVVVOXFISA-M 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000007151 ring opening polymerisation reaction Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000013501 sustainable material Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000013638 trimer Substances 0.000 description 1
- YFHICDDUDORKJB-UHFFFAOYSA-N trimethylene carbonate Chemical compound O=C1OCCCO1 YFHICDDUDORKJB-UHFFFAOYSA-N 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 229920001221 xylan Polymers 0.000 description 1
- 150000004823 xylans Chemical class 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J11/00—Recovery or working-up of waste materials
- C08J11/04—Recovery or working-up of waste materials of polymers
- C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
- C08J11/105—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with enzymes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
- C08J2367/04—Polyesters derived from hydroxy carboxylic acids, e.g. lactones
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
-
- 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
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Preparation Of Compounds By Using Micro-Organisms (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、高分子化合物を完全な循環型として利用することが可能な、酵素による高分子化合物の解重合と再重合に関する。
【０００２】
【従来の技術】
現在、様々な分野において製品からの有用材料の回収および再利用が検討され、サステイナブル（持続可能）材料利用システムの構築が急がれている。高分子材料製品の再利用については、限りのある炭素資源（Ｃ資源）の有効利用と有限エネルギー資源の節約の観点から、使用後はそのまま再使用されるか（この中にはＰＥＴボトルの繊維素材化なども含まれる）、リサイクルされている。リサイクルの方法としては、マテリアルリサイクル法、ケミカルリサイクル法、サーマルリサイクル法などが用いられているが、マテリアルリサイクル法は分子量低下などの品質劣化を伴い、ケミカルリサイクル法はエネルギー多消費型であり、またサーマルリサイクル法は多量の炭酸ガスが発生するなど、それぞれ問題を内包していて、最終的にはどの方法でも廃プラスチックを排出することになり、焼却、埋め立などにより処理されているのが現状である。
炭素資源の有効利用の観点からは、最終的にはケミカルリサイクル法により原料に戻すことが理想的であり、ケミカルリサイクル法には、解重合反応によるモノマーの回収や化学的分解反応による原料モノマーの回収が知られているが、いずれもエネルギー多消費型で環境に対する負荷は大きく、また一般に採算性はない。
【０００３】
本発明者は、先に、酵素を利用することによって消費エネルギーが少なく、かつ完全循環型のポリマー分解およびポリマー製造法を提案した。特願２０００−１９８８６７号は、トリメチレンカーボネート重合体を加水分解酵素の存在下、解重合させてトリメチレンカーボネート（１，３−ジオキサン−２−オン）を製造する方法であり、また、特願２０００−１９８８６６号は、カプロラクトン重合体に加水分解酵素を作用させてカプロラクトンの環状二量体であるジカプロラクトンを製造する方法と、このジカプロラクトンを加水分解酵素の存在下重合させてカプロラクトン重合体を製造する方法である。さらに、特願２００１−１３１７６８号は、前記と同様に加水分解酵素を利用することにより、ポリアルキレンアルカノエートまたはポリ（３−ヒドロキシアルカノエート）を、環状体を主成分とするオリゴマーに解重合する方法、および前記環状オリゴマーを重合する方法に関するものである。
これらの方法における解重合法は、酵素を利用するため低エネルギー消費であり、また、解重合により得られる生成物は、酵素により再び重合して高分子化されるので、炭素資源を無駄無く有効に利用することができ、いわば、完全循環型のポリマー再利用と位置付けることができる。したがって、前記の方法はサステイナブル材料構築の観点からみると、現実的なケミカルリサイクル法である。
【０００４】
しかし、固形のプラスチック材料をそのまま酵素に作用させることは、不可能であり、前記３つの方法においても、プラスチック材料を溶解させるために、アセトニトリル、テトラヒドロフラン、トルエン、ベンゼンなどの有機溶媒を必要とする。特に再重合性の優れた環状オリゴマーを得るためには、大量の有機溶媒を必要とする。しかし、有機溶媒の多くは通常揮発性化合物で環境に放出されると汚染するので、この点が次に解決すべき問題となっている。
【０００５】
一方、超臨界流体は、最近注目を浴びている流体である。超臨界流体は、気相と液相の相変化を示す蒸気圧曲線における臨界点以上の温度、圧力領域にある流体で、気体と液体の中間的性質をもち、密度は液体に近いが、粘性は気体とほぼ同じで非常に低く、物質中の拡散性も液体よりはるかに高いという性質がある。超臨界流体のこの性質を利用して、様々な材料から有用な物質を抽出、あるいは不要物質を除去する分離・精製技術が実現されている。特に二酸化炭素は、無害であり、かつ安価で不燃性であることに加え、３２℃、７．２ＭＰａ程度に加圧すると容易に超臨界流体となるので、熱や有機溶媒に不安定な性質を示す物質を抽出あるいは除去するのに好都合で、従来抽出等に用いられていた有機溶媒に代わる媒体として利用されつつある。たとえば、現在、超臨界流体二酸化炭素を用いてコーヒーあるいは紅茶からカフェインを除去することが工業的に実用化されている。
【０００６】
また、超臨界流体の粘性が低く拡散性が高いという性質は反応溶媒（反応媒体）としても期待が持たれている。すなわち、拡散性が高いことから、不均一系の反応の場合に、拡散律速の制約を受けている反応が促進される。さらに、超臨界流体は、圧力および温度を変えることにより、密度、極性および粘性などの物性を連続的にしかも大きく変えること、つまり、溶媒としての超臨界流体の物性を制御することが容易である。また、反応終了後に系を大気圧に戻すことで、生成物を反応媒体から容易に分離することができる。
この他、超臨界水によるフロン等の難分解性有害物質の分解処理に関する研究も行われている。
また、本発明者は先に、超臨界流体（二酸化炭素、フロロホルム）を用いた、キシランと長鎖アルコールとのワンポットグリコシル化反応を発表した（T.Nakamura,K.Toshima,S.Matsumura,Biotechnology Letters Vol.22,1183-1189 2000;S.Matsumura,T.Nakamura,E.Yao,.K.Toshima,Chemistry Letters,581-582,1999)。このように、超臨界流体は、気体、液体につぐ第三の媒体として期待されているが、超臨界流体を、酵素を用いてポリマーを解重合および再重合する、低エネルギー消費の完全循環型ケミカルリサイクリングに適用するとの報告はされていない。
【０００７】
【発明が解決しようとする課題】
本発明は、前記問題点に鑑みてなされたものであり、その目的は、ポリエステルを再重合可能な解重合生成物に変換する方法、および前記解重合生成物からポリエステルを製造する方法を、低エネルギー消費でかつ環境受容型の方法として提供するものである。
【０００８】
【課題を解決するための手段】
本発明の前記目的は、以下の解重合方法および重合方法を提供することにより解決される。
(１）ポリエステルをリパーゼの存在下、超臨界二酸化炭素中で、超臨界二酸化炭素に対するポリエステルの濃度を０．１〜１０質量％に、かつポリエステルに対する水の濃度を４５〜２００質量％にして環状二量体を主成分とする解重合生成物に解重合させる、ポリエステルの解重合方法。
（２）ポリエステルをリパーゼの存在下、超臨界二酸化炭素中で、超臨界二酸化炭素に対するポリエステルの濃度を０．１〜１０質量％に、かつポリエステルに対する水の濃度を４５〜２００質量％にして環状二量体を主成分とする解重合生成物に解重合させ、得られる前記解重合生成物を、リパーゼの存在下、超臨界二酸化炭素中で重合させることを特徴とするポリエステルの製造方法。
（３）ポリエステルをリパーゼの存在下、超臨界二酸化炭素中で、超臨界二酸化炭素に対するポリエステルの濃度を０．１〜１０質量％に、かつポリエステルに対する水の濃度を４５〜２００質量％にして環状二量体を主成分とする解重合生成物に解重合させ、得られる前記解重合生成物を、重合触媒の存在下、超臨界二酸化炭素中で重合させることを特徴とするポリエステルの製造方法。
【００１０】
【発明の実施の形態】
初めに、ポリエステルを解重合する方法について説明する。本発明の解重合に用いることのできるポリエステルとしては、ポリカルボン酸とポリオールからのポリエステルのほか、ヒドロキシカルボン酸あるいはその分子内エステル（ラクトン）からのポリエステルまたはポリラクトンが含まれる。ポリカルボン酸とポリオールからのポリエステルとしては、ポリブチレンサクシネート、ポリブチレンアジペート、ポリ（ブチレンサクシネート−アジペート）共重合体など、以下のごとき構造式（１）で示される繰り返し単位を有するものが好適に挙げられる。
【００１１】
【化１】
前記構造式（１）中、Ａは炭素数２〜８の直鎖状または分岐状のアルキレン基を表し、Ｂは炭素数２〜６の直鎖状または分岐状のアルキレン基を表す。ＡおよびＢはそれぞれ、２つ以上の異なるもの（すなわち共重合体）であってもよい。さらに、Ａ（ＣＯＯＨ）2で表されるジカルボン酸の５０モル％以下を芳香族ジカルボン酸、たとえばテレフタル酸、フタル酸、イソフタル酸などで置換してもよい。
本発明のポリエステルとしては、前記構造式（１）で示される以外の繰り返し単位、たとえば、以下の構造式(２）および／または(３）で示す繰り返し単位（単位中、Ｄは炭素数２〜６の直鎖状または分岐状のアルキレン基、アルケニレン基またはアルキニレン基を表す）を、５０モル％以下含んでいてもよい。
【００１３】
【化２】
前記ポリエステルの分子量（数平均分子量）は特に制限はなく、また、ポリエステルの末端基部分にはポリマー合成法により決定されるいずれの置換基によって置換されていることが可能である。
【００１５】
また、前記ヒドロキシカルボン酸からのポリエステルまたはポリラクトンとしては、炭素数３〜２０のヒドロキシカルボン酸またはラクトンの重合体の他、下記構造式（４）で示される繰り返し単位を１種以上有するポリエステルまたはポリラクトンも含まれる。
式中、Ｒは水素原子または炭素数１から１２の直鎖状または分岐状のアルキル基を表す。
【００１６】
【化３】
前記Ｒは、水素原子および炭素数１〜１２のアルキル基より選ばれる、異なる２種以上（共重合体）であってもよい。Ｒがメチル基の場合、ポリ（３−ヒドロキシ酪酸）であり、Ｒがメチル基および水素原子の場合３−ヒドロキシ酪酸／３−ヒドロキシプロピオン酸共重合体（ＰＨＢ／ＰＨＰ）であり、Ｒがメチル基およびエチル基の場合３−ヒドロキシ酪酸／３−ヒドロキシバレリアン酸共重合体（ＰＨＢ／ＰＨＶ）である。これらは、微生物が産生するポリマーとして知られている。このポリラクトンの末端基部分にはポリマー合成法により決定されるいずれの置換基によって置換されていることが可能である。
また、前記ポリラクトンは、分子中にさらに以下の構造式（５）ないし(７）で示す繰り返し単位を１種以上有していてもよい。
【００１８】
【化４】
式中Ｒ1は炭素数１〜１７の直鎖または分岐のアルキレン基を、Ｒ2は炭素数２〜１１の直鎖または分岐のアルキレン基を、Ｒ3は炭素数１〜１０の直鎖または分岐のアルキレン基を、Ｒ4は炭素数２〜１０の直鎖または分岐のアルキレン基をそれぞれ表わす。（繰り返し単位（５）を含む場合は、他のラクトンを含む共重合体であることを表す。）
【００２１】
次に、本発明においては超臨界流体としては二酸化炭素が用いられる。二酸化炭素は前記のように、無害、安価、不燃性であり、また、その臨界点は、３２℃、７．２ＭＰａ程度であるので、臨界点に達し易く、本発明の解重合および重合に用いる媒体として好適である。
【００２２】
本発明のポリエステル（以下において「解重合ポリマー」ということがある。）の解重合は、解重合ポリマーとリパーゼを耐圧反応管に入れ、これに液化炭酸を、送液ポンプにより加圧しながら注入することにより、二酸化炭素を超臨界状態にし、超臨界二酸化炭素を適切な温度に保持しつつ、好ましくは攪拌しながら、適切な時間解重合反応をさせることにより行われる。解重合の際の超臨界二酸化炭素の温度は、３１〜９０℃程度、好ましくは４０〜８０℃程度であり、また、圧力は７．２〜３０ＭＰａ程度、好ましくは７．５〜２０ＭＰａ程度である。
また、解重合反応媒体中に含まれる解重合ポリマーの濃度は、０．１〜５０ｇ／Ｌ、中でも１〜２０ｇ／Ｌが適切である。０．１ｇ／Ｌより低い濃度の場合は、収率自体は特に低くないが濃度が低いため得られる解重合生成物の量を十分に確保しにくく、また５０ｇ／Ｌを超えると解重合生成物への変換率が低下するので、前記範囲が好ましい。
また、解重合の反応時間は少なくとも３時間であることが望ましい。反応時間の上限は特にないが、４８時間以上行ってもそれ以上解重合は進行せず経済的に不利となる。
【００２３】
本発明の解重合に用いる酵素であるリパーゼは、固定化していても固定化していなくてもよいが、解重合生成物の回収や酵素の再利用の観点からは固定化しているものが利便である。中でもCandida antarctica由来のリパーゼが好ましい。リパーゼとしては、例えば、Candida antarctica由来の固定化酵素である、ノボザイムズジャパン（株）の「Ｎｏｖｏｚｙｍ ４３５（商品名）」を挙げることができる。
本発明の解重合における固定化リパーゼの添加量は、ポリマー当たり１〜１０００質量％、好ましくは、１〜５００質量％、より好ましくは５〜２００質量％である。１質量％未満では、解重合反応が著しく低下し、また、１０００質量％を超えても解重合生成物の収量に顕著な変化はみられないので、前記範囲が適切である。
【００２４】
さらに、解重合の系の中に全く水が存在しないとリパーゼの活性が保てないので、系に微量の水分を添加することが好ましい。リパーゼ自体が水分を保持している場合には、水を添加する必要はない。リパーゼの活性を保つための水分は、反応系中解重合ポリマーに対して０．１〜１０００質量％程度である。
【００２５】
ポリエステルの解重合生成物は、線状あるいは環状のオリゴマーまたはモノマーである（ただし環状二量体を主成分とする。）。解重合条件により環状のものが多く得られたり、線状のものが多く得られたりするが、本発明においては、環状オリゴマーを多く得るために、解重合ポリマーに対する水分濃度を低く（４５〜２００質量％）、また、反応媒体に対する解重合ポリマーの濃度を低く（０．１〜１０質量％）する。いずれのオリゴマーおよびモノマーも再重合によりもとのポリマーに再生させることが可能である。特に環状オリゴマーの再重合は、開環重合であるため、水等の縮合成分が発生せず、これらを反応系外に出す必要もないので、重合反応操作が簡便であるというメリットがある。
また、オリゴマーの分子量は、温度、圧力、解重合ポリマー濃度等の反応条件にもよるが、一般に５００以下である。
【００２６】
環状オリゴマーを多く生成させるための条件で解重合させると、たとえば、ポリカプロラクトンではカプロラクトンの環状二量体であるジカプロラクトン（１，８−ジオキサシクロテトラデカリン−２，９−ジオン）を主生成物として得ることができる。また、前記構造式（１）および（４）で示される繰り返し単位を有するポリエステルからは、後述の実施例４及び６で示される環状二量体を主生成物として得ることができる。
【００２７】
［前記解重合生成物の重合］
（リパーゼを用いる方法）
本発明のポリエステルからの解重合生成物は、リパーゼの存在下、超臨界二酸化炭素中で重合させることが可能である。解重合生成物とリパーゼを耐圧反応管に入れ、これに液化炭酸を、送液ポンプにより加圧しながら注入することにより、二酸化炭素を超臨界状態にし、超臨界二酸化炭素を適切な温度に保持しつつ、好ましくは攪拌しながら、適切な時間解重合反応をさせることにより行われる。解重合の際の超臨界二酸化炭素の温度は、３１〜８５℃程度、好ましくは４０〜７５℃程度であり、また、圧力は７．２〜３０ＭＰａ程度、好ましくは７．５〜２０ＭＰａ程度である。
また、重合反応溶液中に含まれる解重合生成物の濃度は、０．１〜５０ｇ／Ｌ、中でも１〜２０ｇ／Ｌが適切である。０．１ｇ／Ｌより低い濃度の場合は、収率自体は特に低くないが濃度が低いため得られるポリマーの量を十分に確保しにくく、また５０ｇ／Ｌを超えるとポリマーへの変換率が低下するので、前記範囲が好ましい。
また、重合時間は、０．５〜４８時間が適当である。０．５時間より短いと十分反応が進行せず、また、４８時間を超えると生成したポリマーが解重合を起こしたりするので、前記範囲が好ましい。
【００２８】
本発明の解重合生成物を重合させるのに用いる固定化リパーゼの添加量は、解重合生成物に対してリパーゼ０．１〜５０質量％、好ましくは、リパーゼ０．１〜１０質量％である。０．１質量％未満では、重合速度が低下し、モノマー変換率も低くなりやすく、また、５０質量％を超えると生成するポリマーの分子量が低くなりやすいので、前記範囲が適切である。
【００２９】
本発明の重合法により、数平均分子量で１万程度までの分子量のポリエステルが得られる。前記解重合生成物のポリマーへの変換率は１００％を達成することも可能である。
【００３０】
（化学的合成方法）
ポリエステルの一例を挙げると、絶対乾燥条件下、解重合生成物に対して０．１質量％のジスタノキサンを触媒として加え、１００℃で、塊状重合を行うことにより対応するポリエステルを得ることができる。
【００３６】
本発明の解重合方法および重合方法は、超臨界二酸化炭素を反応溶媒として用いるため、反応後に系の圧力を常圧に戻すだけで、反応溶媒を系外に容易に放出することができ、系から生成物を分離することが容易である。また、放出された反応溶媒を回収して再利用することも可能である。更に、溶媒が反応系外に漏れた場合でも環境を汚染する虞はない。
さらに、通常の有機溶媒を用いた解重合方法および重合方法に比較して、解重合および重合の反応効率に遜色はなく、リパーゼを用いる解重合反応の場合、ポリマーを１００％解重合させるのに必要な時間は、トルエンを用いる場合より若干長くなるものの、アセトニトリルを用いた場合に比較すると顕著に短くなる。
また、本発明のリパーゼを用いる解重合方法および重合方法は、ワンポットによる簡便な操作でよい他、反応条件は温和でありまた低エネルギー消費でもある。さらに解重合により得られるオリゴマーおよびモノマーは再重合によりもとのポリマーに再生させることが可能である。そして、解重合または重合を行うのに用いるリパーゼは、回収して繰り返し用いることができ、その際酵素としての活性の減少は実質的にないという有利な点を有する。
したがって、本発明により、環境受容型であり、かつ炭素資源を完全再利用することが可能な、完全循環型の高分子材料利用システムを構築することが可能になった。
【００３７】
【実施例】
以下に実施例を示し本発明をさらに具体的に説明するが、本発明はこれらの実施例により限定されるものではない。
【００３９】
実施例１
１４員環ジカプロラクトン（１，８−ｄｉｏｘａｃｙｃｌｏｔｅｔｒａｄｅｃａｎｅ−２，９−ｄｉｏｎｅ）を（５０ｍｇ）および固定化リパーゼ（Ｎｏｖｏｚｙｍ ４３５）（５ｍｇ）を１０ｍＬステンレス製耐圧反応管に秤り取り、次いで、液化炭酸を８ＭＰａで充填し、超臨界二酸化炭素中、磁気撹拌子を用いて７０℃で６時間８ＭＰａで撹拌を行い重合を行った。反応終了後、反応管をドライアイス−メタノール浴で冷却し、ガス導入用コックを開け、徐々に炭酸ガスを排気し、常圧に戻した後、反応管中の重合物にクロロホルムを少量加え、不溶の固定化リパーゼをセライトを用いて濾別し、濾液よりクロロホルムをエバポレーターを用いて減圧濃縮し、ポリカプロラクトンをほぼ定量的に得た。ＧＰＣ法により分子量を測定したところ、Ｍｗ＝４８，０００、Ｍｎ＝２６，０００，Ｍｗ／Ｍｎ＝１．８であった。
【００４２】
実施例２
１４員環ジカプロラクトン（１，８−ｄｉｏｘａｃｙｃｌｏｔｅｔｒａｄｅｃａｎｅ−２，９−ｄｉｏｎｅ）（２００ｍｇ）、オレイン酸カリウム（１．５ｍｇ）および１８−クラウン−６（１．２ｍｇ）を、１０ｍＬステンレス製耐圧反応管に秤り取り、次いで、液化炭酸を１０ＭＰａで充填し、超臨界二酸化炭素中、磁気撹拌子を用いて４０℃で２４時間１０ＭＰａで撹拌を行い重合を行った。反応終了後、反応管をドライアイス−メタノール浴で冷却し、ガス導入用コックを開け、徐々に炭酸ガスを排気し、常圧に戻した後、反応管中の重合物にクロロホルムを少量加え、不溶物を濾別し、濾液よりクロロホルムをエバポレーターを用いて減圧濃縮し、ポリカプロラクトンを得た。ＧＰＣ法により分子量を測定したところ、Ｍｗ＝３０，０００、Ｍｎ＝２０，０００，Ｍｗ／Ｍｎ＝１．５であった。
【００４４】
実施例３
ポリ（カプロラクトン）（分子量Ｍｎ＝１１０，０００，Ｍｗ／Ｍｎ＝１．６）２５ｍｇ、固定化リパーゼ（Ｎｏｖｏｚｙｍ４３５）１０ｍｇおよび水１２ｍｇを１０ｍＬステンレス製耐圧反応管に秤り取り、ついで液化炭酸を１６ＭＰａで充填し、超臨界二酸化炭素中、磁気攪拌子を用いて４０℃で６時間、１６ＭＰａで攪拌を行い分解を行った。反応終了後、反応管をドライアイス−メタノール浴で冷却し、ガス導入用コックを開け、徐々に炭酸ガスを排気した。常圧に戻した後、反応管中に残った分解物にクロロホルムを少量加え、不溶の固定化リパーゼをセライトを用いて濾別し、濾液より溶媒をエバポレーターを用いて減圧濃縮し、環状ジカプロラクトンを９２％含む再重合性オリゴマーをほぼ定量的に得た。環状ジカプロラクトンの定量はＧＰＣおよびＭＡＬＤＩ−ＴＯＦ ＭＳによった。また、環状ジカプロラクトン生成の確認は、粗生成物のテトラヒドロフラン（ＴＨＦ）溶液から再結晶を行うことにより精製し、分析を行った。結果を以下に示す。
【００４５】
融点（ｍ．ｐ）１１３−１１５℃（文献値１１１−１１３℃）．［Ｆ．Ｊ．Ｖａｎ Ｎａｔｔａ，Ｊ．Ｗ．Ｈｉｌｌ，Ｗ．Ｈ．Ｃａｒｏｔｈｅｒｓ，Ｊ．Ａｍ．Ｃｈｅｍ．Ｓｏｃ．１９３４，５６，４５５．］
赤外分光スペクトル ＩＲ（ＫＢｒ）：２９３６，２８６６（ＣＨ2），１７２１（ＣＯＯ，ｅｓｔｅｒ），１４７２ｃｍ-1（ＣＨ2）．1Ｈ−ＮＭＲ（３００ＭＨｚ，ＣＤＣｌ3）：δ＝１．３５−１．７５（ｍ，１２Ｈ，ＣＨ2ｏｆＣ−３，３’，４，４’，５ａｎｄ５’），２．３８（ｔ，Ｊ＝６．０５Ｈｚ，４Ｈ，ＣＨ2ｏｆＣ−２ａｎｄ２’），４．１６（ｔ，Ｊ＝５．６３Ｈｚ，４Ｈ，ＣＨ2ｏｆＣ−６ａｎｄ６’）．13Ｃ−ＮＭＲ（７５ＭＨｚ，ＣＤＣｌ3）：δ＝２４．６，２８．１（Ｃ−３，３’，４，４’，５ａｎｄ５’，ＣＨ2），３４．６（Ｃ−２ａｎｄ２’，ＣＨ2），６３．０（Ｃ−６ａｎｄ６’，ＣＨ2），１７３．５（Ｃ−１ａｎｄ１’，Ｃ＝０）．
元素分析値 Ｃ12Ｈ20Ｏ4（２２８．３）：計算値 Ｃ６３．１３；Ｈ８．８３；理論値 Ｃ６３．１２；Ｈ８．７９．
【００４６】
同様にして、超臨界二酸化炭素の圧力を変化させたときの環状ジカプロラクトン（ＤＣＬ）の収率の変化を図１に示す。図１よりＤＣＬの収率は圧力を上げるにつれて上昇し、１６ＭＰａで最大値に達し、それ以上圧力を上げても効果は認められなかった。なお、この範囲の圧力では、圧力を変えることによりＤＣＬの含量のみが変化し、環状ジカプロラクトンを含む環状体を主成分とするオリゴマーにほぼ定量的に変換されていた。
【００４７】
また、１６ＭＰａで反応を行ったときの温度と環状ジカプロラクン（ＤＣＬ）の収率の関係（６時間反応）を図２に示す。
図２より、反応温度は４０〜５０℃でＤＣＬの最高収率が得られることが分かった。これ以上の反応温度では、酵素の活性が低下し、収率も低下する。
環状ジカプロラクン（ＤＣＬ）の収率は初めに添加する水分量にも大きく依存しており、水分量が極端に多くなれば加水分解により線状ヒドロキシ酸が多くなる。反応系における水分量と環状ジカプロラクン（ＤＣＬ）の収率の関係を図３に示す。
【００４８】
実施例４
ポリ（ブチレンアジぺート）（分子量Ｍｗ２２，０００）３０ｍｇ、固定化リパーゼ（Ｎｏｖｏｚｙｍ ４３５）３０ｍｇおよび水２０ｍｇを、１０ｍＬステンレス製耐圧反応管に秤り取り、ついで液化炭酸を１６ＭＰａで充填し、超臨界二酸化炭素中、磁気攪拌子を用いて４０℃で６時間、１６ＭＰａで攪拌を行い分解を行った。反応終了後、反応管をドライアイス−メタノール浴で冷却し、ガス導入用コックを開け、徐々に炭酸ガスを排気した。常圧に戻した後、反応管中に残った分解物にクロロホルムを少量加え、不溶の固定化リパーゼをセライトを用いて濾別し、濾液より溶媒をエバポレーターを用いて減圧濃縮し、環状ブチレンアジペート２量体（前記構造式（８）においてＬ：（ＣＨ2）4，Ｍ（ＣＨ2）4ｍ＝２）を主成分とする再重合性オリゴマーをほぼ定量的に得た。環状ブチレンアジペート２量体の定量はＧＰＣおよびＭＡＬＤＩ−ＴＯＦ ＭＳによった。また、環状ブチレンアジペート２量体生成の確認は、粗生成物をカラムクロマトグラフィーにより精製し、分析を行った。
1Ｈ−ＮＭＲ（３００ＭＨｚ，ＣＤＣｌ3）：δ（ｐｐｍ）＝４．１２（−ＣＨ2−Ｏ−ＣＯ−）（４Ｈ，ｍ），２．３４（−ＣＨ2−ＣＯ−Ｏ）（４Ｈ，ｍ），１．７３（−ＣＯ−ＣＨ2−ＣＨ2−ＣＨ2−ＣＨ2−ＣＯ−）（４Ｈ，ｍ），１．６８（−Ｏ−ＣＨ2−ＣＨ2−ＣＨ2−ＣＨ2−Ｏ−）（４Ｈ，ｍ）．
【００４９】
実施例５
実施例４で得た環状ブチレンアジペート２量体５０ｍｇおよび固定化リパーゼ（Ｎｏｖｏｚｙｍ ４３５）５ｍｇを、１０ｍＬステンレス製耐圧反応管に秤り取り、ついで液化炭酸を８ＭＰａで充填し、超臨界二酸化炭素中、磁気攪拌子を用いて７０℃で６時間、８ＭＰａで攪拌を行い重合を行った。反応終了後、反応管をドライアイス−メタノール浴で冷却し、徐々に炭酸ガスを排気し、常圧に戻した後、反応管中の重合物にクロロホルムを少量加え、不溶の固定化リパーゼをセライトを用いて濾別し、濾液より溶媒をエバポレーターを用いて減圧濃縮し、ポリ（ブチレンアジペート）をほぼ定量的に得た。ＧＰＣ法により分子量を測定したところ、Ｍｗ＝５２，０００であった。
【００５０】
実施例６
ポリ（ブチレンサクシネート）（分子量Ｍｗ９９，０００）２５ｍｇ、固定化リパーゼ（Ｎｏｖｏｚｙｍ ４３５）３０ｍｇおよび水１２ｍｇを、１０ｍＬステンレス製耐圧反応管に秤り取り、ついで液化炭酸を１６ＭＰａで充填し、超臨界二酸化炭素中、磁気攪拌子を用いて４０℃で６時間、１６ＭＰａで攪拌を行い分解を行った。反応終了後、反応管をドライアイス−メタノール浴で冷却し、ガス導入用コックを開け、徐々に炭酸ガスを排気した。常圧に戻した後、反応管中に残った分解物にクロロホルムを少量加え、不溶の固定化リパーゼをセライトを用いて濾別し、濾液より溶媒をエバポレーターを用いて減圧濃縮し、環状２〜３量体を主成分とする再重合性オリゴマーを得た。環状ブチレンサクシネート２量体（前記構造式（８）においてＬ：（ＣＨ2）2，Ｍ（ＣＨ2）4ｍ＝２）の定量はＧＰＣおよびＭＡＬＤＩ−ＴＯＦ ＭＳによった。また、環状ブチレンサクシネート２量体生成の確認は、粗生成物をカラムクロマトグラフィーにより精製し、分析を行った。
1Ｈ−ＮＭＲ（３００ＭＨｚ，ＣＤＣｌ3）：δ（ｐｐｍ）＝４．１１（−ＣＨ2−Ｏ−ＣＯ−）（４Ｈ，ｍ），２．６３（−ＣＨ2−ＣＯ−Ｏ）（４Ｈ，ｍ），１．７１（−Ｏ−ＣＨ2−ＣＨ2−ＣＨ2−ＣＨ2−Ｏ−）（４Ｈ，ｍ）．
【００５１】
【発明の効果】
本発明の解重合方法および重合方法は、超臨界二酸化炭素を反応溶媒として用いるため、反応後に系の圧力を常圧に戻すだけで、反応溶媒を系外に容易に放出することができ、系から生成物を分離することが容易である。また、放出された反応溶媒を回収して再利用することも可能である。更に、溶媒が反応系外に漏れた場合でも環境を汚染する虞はない。
さらに、通常の有機溶媒を用いた解重合方法および重合方法に比較して、解重合および重合の反応効率に遜色はなく、リパーゼを用いる解重合反応の場合、ポリマーを１００％解重合させるのに必要な時間は、トルエンを用いる場合より若干長くなるものの、アセトニトリルを用いた場合に比較すると顕著に短くなる。
また、本発明のリパーゼを用いる解重合方法および重合方法は、ワンポットによる簡便な操作でよい他、反応条件は温和でありまた低エネルギー消費でもある。さらに解重合により得られるオリゴマーおよびモノマーは再重合によりもとのポリマーに再生させることが可能である。そして、解重合または重合を行うのに用いるリパーゼは、回収して繰り返し用いることができ、その際酵素としての活性の減少は実質的にないという有利な点を有する。
したがって、本発明により、環境受容型であり、かつ炭素資源を完全再利用することが可能な、完全循環型の高分子材料利用システムを構築することが可能になった。
【図面の簡単な説明】
【図１】 実施例３において超臨界二酸化炭素の圧力と環状ジカプロラクトンの収率との関係を示すグラフである。
【図２】 実施例３において反応温度と環状ジカプロラクトンの収率との関係を示すグラフである。
【図３】 実施例３において反応系における水分含有量と環状ジカプロラクトンの収率との関係を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to depolymerization and repolymerization of a polymer compound by an enzyme, which can utilize the polymer compound as a complete circulation type.
[0002]
[Prior art]
Currently, in various fields, collection and reuse of useful materials from products are being studied, and the construction of a sustainable (sustainable) material utilization system is urgently needed. Regarding the reuse of polymer material products, from the viewpoint of effective utilization of limited carbon resources (C resources) and saving of limited energy resources, they can be reused as they are (including PET bottle fibers) Recycling is also included). As recycling methods, the Material Recycling Law, Chemical Recycling Law, Thermal Recycling Law, etc. are used, but the Material Recycling Law is accompanied by quality degradation such as a decrease in molecular weight, and the Chemical Recycling Law is energy intensive. The Thermal Recycling Law has problems such as the generation of a large amount of carbon dioxide gas. Each method eventually discharges waste plastic, and is currently treated by incineration, landfill, etc. It is.
From the viewpoint of effective utilization of carbon resources, it is ideal to return to the raw material by the chemical recycling method. The chemical recycling method uses the recovery of monomer by depolymerization reaction and the raw material monomer by chemical decomposition reaction. Although recovery is known, all of them are energy intensive, have a heavy environmental impact, and are generally not profitable.
[0003]
The present inventor has previously proposed a method for polymer degradation and production of a polymer that consumes less energy by using an enzyme and is completely circulated. Japanese Patent Application No. 2000-198867 is a process for producing trimethylene carbonate (1,3-dioxan-2-one) by depolymerizing a trimethylene carbonate polymer in the presence of a hydrolase. No. 2000-198866 describes a method for producing dicaprolactone, which is a cyclic dimer of caprolactone, by reacting a caprolactone polymer with a hydrolase, and polymerizing the dicaprolactone in the presence of the hydrolase to produce a caprolactone polymer. It is a manufacturing method. Furthermore, Japanese Patent Application No. 2001-131768 depolymerizes polyalkylene alkanoate or poly (3-hydroxyalkanoate) into an oligomer mainly composed of a cyclic product by utilizing a hydrolase as described above. The present invention relates to a method and a method for polymerizing the cyclic oligomer.
In these methods, the depolymerization method uses an enzyme and consumes low energy, and the product obtained by the depolymerization is polymerized again by the enzyme to be polymerized. In other words, it can be regarded as a completely recycled polymer recycling. Therefore, the above method is a realistic chemical recycling method from the viewpoint of building a sustainable material.
[0004]
However, it is impossible to allow a solid plastic material to act on an enzyme as it is, and even in the above three methods, an organic solvent such as acetonitrile, tetrahydrofuran, toluene, or benzene is required to dissolve the plastic material. . In particular, a large amount of organic solvent is required to obtain a cyclic oligomer having excellent repolymerization properties. However, many organic solvents are usually volatile compounds that are contaminated when released to the environment, and this is the next problem to be solved.
[0005]
On the other hand, a supercritical fluid is a fluid that has recently attracted attention. A supercritical fluid is a fluid that is in the temperature and pressure region above the critical point in the vapor pressure curve showing the phase change between the gas phase and the liquid phase, has an intermediate property between gas and liquid, has a density close to that of a liquid, but is viscous. Is almost the same as a gas and is very low, and has a property that the diffusivity in a substance is much higher than that of a liquid. Utilizing this property of the supercritical fluid, separation / purification techniques for extracting useful substances from various materials or removing unnecessary substances have been realized. In particular, carbon dioxide is harmless, inexpensive and non-flammable, and can easily become a supercritical fluid when pressurized to about 7.2 MPa at 32 ° C. It is convenient for extracting or removing the substances to be shown, and is being used as a medium replacing an organic solvent conventionally used for extraction or the like. For example, at present, it is industrially practical to remove caffeine from coffee or tea using supercritical fluid carbon dioxide.
[0006]
In addition, the property of a supercritical fluid having low viscosity and high diffusibility is expected as a reaction solvent (reaction medium). That is, since the diffusibility is high, in the case of a heterogeneous reaction, a reaction that is restricted by diffusion rate control is promoted. Furthermore, the supercritical fluid can easily change the physical properties such as density, polarity and viscosity continuously and greatly by changing the pressure and temperature, that is, it is easy to control the physical properties of the supercritical fluid as a solvent. . In addition, the product can be easily separated from the reaction medium by returning the system to atmospheric pressure after completion of the reaction.
In addition, research on the decomposition treatment of refractory harmful substances such as chlorofluorocarbon with supercritical water is also being conducted.
The present inventor previously announced a one-pot glycosylation reaction between xylan and a long-chain alcohol using a supercritical fluid (carbon dioxide, fluoroform) (T. Nakamura, K. Toshima, S. Matsumura, Biotechnology). Letters Vol. 22, 1183-1189 2000; S. Matsumura, T. Nakamura, E. Yao, K. Toshima, Chemistry Letters, 581-582, 1999). In this way, supercritical fluid is expected as a third medium that connects to gas and liquid, but supercritical fluid is a complete circulation type with low energy consumption that depolymerizes and repolymerizes polymer using enzymes. It has not been reported to be applied to chemical recycling.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and its purpose is to provide polyester.LeMethod for converting to repolymerizable depolymerization product, and from said depolymerization product to polyesterLeThe manufacturing method is provided as an environment-accepting method with low energy consumption.
[0008]
[Means for Solving the Problems]
The object of the present invention is solved by providing the following depolymerization method and polymerization method.
(1) PolyesterLipase leSupercritical in the presence ofcarbon dioxideIn supercriticalcarbon dioxidePolyester againstLeConcentrate to 0.1-10% by mass and polyesterLeThe water concentration is 45-200% by massDimerTo depolymerize a depolymerized product mainly composed ofLeDepolymerization method.
(2) PolyesterLipase leSupercritical in the presence ofcarbon dioxideIn supercriticalcarbon dioxidePolyester againstLeConcentrate to 0.1-10% by mass and polyesterLeThe water concentration is 45-200% by massDimerIs depolymerized into a depolymerized product containing as a main component, and the resulting depolymerized product isLipaseSupercritical in the presence ofcarbon dioxidePolyester characterized by being polymerized inLeProduction method.
(3) PolyesterLipase leSupercritical in the presence ofcarbon dioxideIn supercriticalcarbon dioxidePolyester againstLeConcentrate to 0.1-10% by mass and polyesterLeThe water concentration is 45-200% by massDimerIn the presence of a polymerization catalyst and supercritical.carbon dioxidePolyester characterized by being polymerized inLeProduction method.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
First, PolyesterLeA method for depolymerization will be described. Polyesters that can be used in the depolymerization of the present invention include polyesters from polycarboxylic acids and polyols, as well as polyesters or polylactones from hydroxycarboxylic acids or their intramolecular esters (lactones). Examples of polyesters from polycarboxylic acids and polyols include those having a repeating unit represented by the following structural formula (1), such as polybutylene succinate, polybutylene adipate, and poly (butylene succinate-adipate) copolymer. Preferably mentioned.
[0011]
[Chemical 1]
In the structural formula (1), A represents a linear or branched alkylene group having 2 to 8 carbon atoms, and B represents a linear or branched alkylene group having 2 to 6 carbon atoms. Each of A and B may be two or more different (ie, copolymers). Furthermore, A (COOH)2Or less than 50 mol% of the dicarboxylic acid represented by the formula (1) may be substituted with an aromatic dicarboxylic acid such as terephthalic acid, phthalic acid, isophthalic acid or the like.
Examples of the polyester of the present invention include repeating units other than those represented by the structural formula (1), for example, repeating units represented by the following structural formulas (2) and / or (3) (in the unit, D represents 2 to 2 carbon atoms). 6 linear or branched alkylene groups, alkenylene groups or alkynylene groups) may be contained in an amount of 50 mol% or less.
[0013]
[Chemical 2]
The molecular weight (number average molecular weight) of the polyester is not particularly limited, and the terminal group portion of the polyester can be substituted with any substituent determined by a polymer synthesis method.
[0015]
Moreover, as the polyester or polylactone derived from the hydroxycarboxylic acid, in addition to a polymer of a hydroxycarboxylic acid or lactone having 3 to 20 carbon atoms, a polyester or polylactone having one or more repeating units represented by the following structural formula (4) Is also included.
In the formula, R represents a hydrogen atom or a linear or branched alkyl group having 1 to 12 carbon atoms.
[0016]
[Chemical 3]
The R may be two or more different types (copolymers) selected from a hydrogen atom and an alkyl group having 1 to 12 carbon atoms. When R is a methyl group, it is poly (3-hydroxybutyric acid). When R is a methyl group and a hydrogen atom, it is a 3-hydroxybutyric acid / 3-hydroxypropionic acid copolymer (PHB / PHP), and R is methyl. In the case of a group and an ethyl group, it is a 3-hydroxybutyric acid / 3-hydroxyvaleric acid copolymer (PHB / PHV). These are known as polymers produced by microorganisms. The terminal group portion of the polylactone can be substituted with any substituent determined by a polymer synthesis method.
The polylactone may further have one or more repeating units represented by the following structural formulas (5) to (7) in the molecule.
[0018]
[Formula 4]
Where R1Is a linear or branched alkylene group having 1 to 17 carbon atoms, R2Is a linear or branched alkylene group having 2 to 11 carbon atoms, RThreeIs a linear or branched alkylene group having 1 to 10 carbon atoms, RFourRepresents a linear or branched alkylene group having 2 to 10 carbon atoms. (When the repeating unit (5) is included, it represents a copolymer containing another lactone.)
[0021]
Next, in the present inventionIsCarbon dioxide as a supercritical fluidIs used. twoAs described above, carbon oxide is harmless, inexpensive, and non-flammable, and its critical point is about 32 ° C. and about 7.2 MPa, so that it easily reaches the critical point and is used for depolymerization and polymerization of the present invention. Suitable as a medium.
[0022]
Polyester of the present inventionLe (Smell"Sometimes referred to as “depolymerized polymer”. ) Depolymerization and depolymerization polymerLipaseIs put in a pressure-resistant reaction tube, and liquefied carbonic acid is injected into the pressure-resistant reaction tube while pressurizing with a liquid feed pump, thereby bringing the carbon dioxide into a supercritical state and preferably stirring while maintaining the supercritical carbon dioxide at an appropriate temperature. However, it is carried out by carrying out an appropriate time depolymerization reaction. The temperature of supercritical carbon dioxide during depolymerization is about 31 to 90 ° C, preferably about 40 to 80 ° C, and the pressure is about 7.2 to 30 MPa, preferably about 7.5 to 20 MPa. .
The concentration of the depolymerized polymer contained in the depolymerization reaction medium is suitably 0.1 to 50 g / L, particularly 1 to 20 g / L. When the concentration is lower than 0.1 g / L, the yield itself is not particularly low, but the concentration is low, so that it is difficult to secure a sufficient amount of the depolymerized product, and when it exceeds 50 g / L, the depolymerized product is exceeded. The above-mentioned range is preferable because the conversion rate to is reduced.
The depolymerization reaction time is preferably at least 3 hours. Although there is no upper limit for the reaction time, depolymerization does not proceed any longer even if it is performed for 48 hours or more, which is economically disadvantageous.
[0023]
Enzyme used for depolymerization of the present inventionLipaseMay or may not be immobilized, but from the viewpoint of recovery of the depolymerized product and reuse of the enzyme, the immobilized one is convenient.. During ~However, lipases derived from Candida antarctica are preferred. Examples of the lipase include “Novozym 435 (trade name)” of Novozymes Japan, which is an immobilized enzyme derived from Candida antarctica.
Immobilization in the depolymerization of the present inventionLipaseIs added in an amount of 1-1000 mass%, preferably 1-500 mass%, more preferably 5-200 mass% per polymer. When the amount is less than 1% by mass, the depolymerization reaction is remarkably reduced, and when the amount exceeds 1000% by mass, no significant change is observed in the yield of the depolymerized product, so the above range is appropriate.
[0024]
Furthermore, if there is no water in the depolymerization systemLipaseTherefore, it is preferable to add a small amount of water to the system.LipaseWhen the water itself retains moisture, it is not necessary to add water.LipaseThe water content for maintaining the activity is about 0.1 to 1000% by mass relative to the depolymerized polymer in the reaction system.
[0025]
PolyesteLeThe depolymerization product is a linear or cyclic oligomer or monomer(However, a cyclic dimer is the main component.)Depending on the depolymerization conditions, many cyclic products or many linear products can be obtained.But,In the present invention, in order to obtain a large amount of cyclic oligomer, the water concentration with respect to the depolymerized polymer is low (45 to 200% by mass), and the concentration of the depolymerized polymer with respect to the reaction medium is low (0.1 to 10% by mass). Do. NoMisaligned oligomers and monomers can also be regenerated to the original polymer by repolymerization. In particular, the re-polymerization of the cyclic oligomer is a ring-opening polymerization, so that no condensation component such as water is generated, and there is no need to take them out of the reaction system, so that there is an advantage that the polymerization reaction operation is simple.
The molecular weight of the oligomer is generally 500 or less, although it depends on the reaction conditions such as temperature, pressure and depolymerized polymer concentration.
[0026]
For example, polycaprolactone produces mainly dicaprolactone (1,8-dioxacyclotetradecalin-2,9-dione), which is a cyclic dimer of caprolactone, when it is depolymerized under conditions for generating a large amount of cyclic oligomers. Can get as a thingwear. Further, from the polyester having a repeating unit represented by the structural formulas (1) and (4),Examples 4 and 6The ring indicated byDimerCan be obtained as the main product.
[0027]
[Polymerization of the depolymerized product]
(LipaseMethod using
Polyester of the present inventionLeThese depolymerized products areLipaseIt is possible to polymerize in supercritical carbon dioxide in the presence of. Depolymerized products andLipaseIs put in a pressure-resistant reaction tube, and liquefied carbonic acid is injected into the pressure-resistant reaction tube while pressurizing with a liquid feed pump, thereby bringing the carbon dioxide into a supercritical state and preferably stirring while maintaining the supercritical carbon dioxide at an appropriate temperature. However, it is carried out by carrying out an appropriate time depolymerization reaction. The temperature of supercritical carbon dioxide during depolymerization is about 31 to 85 ° C, preferably about 40 to 75 ° C, and the pressure is about 7.2 to 30 MPa, preferably about 7.5 to 20 MPa. .
Further, the concentration of the depolymerization product contained in the polymerization reaction solution is suitably 0.1 to 50 g / L, particularly 1 to 20 g / L. When the concentration is lower than 0.1 g / L, the yield itself is not particularly low, but the concentration is low, so it is difficult to secure a sufficient amount of polymer, and when it exceeds 50 g / L, the conversion rate to the polymer decreases. Therefore, the above range is preferable.
The polymerization time is suitably 0.5 to 48 hours. When the time is shorter than 0.5 hours, the reaction does not proceed sufficiently, and when the time exceeds 48 hours, the produced polymer causes depolymerization. Therefore, the above range is preferable.
[0028]
Used to polymerize the depolymerized product of the present inventionRuStylizationLipaseIs added to the depolymerized product.Lipase0.1 to 50% by weight, preferablyLipaseIt is 0.1-10 mass%. If the amount is less than 0.1% by mass, the polymerization rate decreases and the monomer conversion rate tends to be low, and if it exceeds 50% by mass, the molecular weight of the polymer to be formed tends to be low.
[0029]
By the polymerization method of the present invention, a polyester having a number average molecular weight of up to about 10,000 is obtained.Be. The conversion rate of the depolymerized product into a polymer can be 100%.
[0030]
(Chemical synthesis method)
As an example of polyester, 0.1% by mass of distanoxane is added as a catalyst to the depolymerized product under absolute drying conditions, and the corresponding polyester can be obtained by bulk polymerization at 100 ° C.The
[0036]
The depolymerization method and polymerization method of the present invention are supercritical.carbon dioxideIs used as a reaction solvent, the reaction solvent can be easily released out of the system by simply returning the system pressure to normal pressure after the reaction, and the product can be easily separated from the system. It is also possible to recover and reuse the released reaction solvent.MoreEven if the solvent leaks out of the reaction system, there is no possibility of contaminating the environment.
Furthermore, the depolymerization and polymerization reaction efficiency is comparable to the depolymerization method and polymerization method using ordinary organic solvents.LipaseIn the case of the depolymerization reaction using, the time required for 100% depolymerization of the polymer is slightly longer than when toluene is used, but is significantly shorter than when acetonitrile is used.
In addition, the present inventionLipaseThe depolymerization method and the polymerization method using a simple one-pot operation may be used, and the reaction conditions are mild and low energy consumption. Furthermore, the oligomer and monomer obtained by depolymerization can be regenerated to the original polymer by repolymerization. And used to perform depolymerization or polymerizationLipaseCan be recovered and used repeatedly, with the advantage that there is virtually no decrease in enzymatic activity.
Therefore, according to the present invention, it has become possible to construct a system for utilizing a polymer material that is environmentally acceptable and that can completely reuse carbon resources.
[0037]
【Example】
Examples The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.Yes.
[0039]
Example1
14-membered ring dicaprolactone (1,8-dioxacyclotetradecane-2,9-dione) (50 mg) and immobilized lipase (Novozym 435) (5 mg) were weighed into a 10 mL stainless steel pressure-resistant reaction tube, and then liquefied carbonic acid was added. Polymerization was carried out by charging at 8 MPa and stirring in supercritical carbon dioxide using a magnetic stir bar at 70 ° C. for 6 hours at 8 MPa. After completion of the reaction, the reaction tube is cooled in a dry ice-methanol bath, the gas introduction cock is opened, the carbon dioxide gas is gradually exhausted, and after returning to normal pressure, a small amount of chloroform is added to the polymer in the reaction tube, Insoluble immobilized lipase was filtered off using celite, and chloroform was concentrated from the filtrate under reduced pressure using an evaporator to obtain polycaprolactone almost quantitatively. When the molecular weight was measured by the GPC method, it was Mw = 48,000, Mn = 26,000, Mw / Mn = 1.8.
[0042]
Example2
14-membered ring dicaprolactone (1,8-dioxacyclotetradecane-2,9-dione) (200 mg), potassium oleate (1.5 mg) and 18-crown-6 (1.2 mg) were added to a 10 mL stainless steel pressure-resistant reaction tube. Weighed and then filled with liquefied carbonic acid at 10 MPa, and polymerization was carried out in supercritical carbon dioxide by stirring at 10 MPa for 24 hours at 40 ° C. using a magnetic stirrer. After completion of the reaction, the reaction tube is cooled in a dry ice-methanol bath, the gas introduction cock is opened, the carbon dioxide gas is gradually exhausted, and after returning to normal pressure, a small amount of chloroform is added to the polymer in the reaction tube, Insoluble matter was filtered off, and chloroform was concentrated from the filtrate under reduced pressure using an evaporator to obtain polycaprolactone. When the molecular weight was measured by the GPC method, it was Mw = 30,000, Mn = 20,000, Mw / Mn = 1.5.
[0044]
Example3
25 mg of poly (caprolactone) (molecular weight Mn = 110,000, Mw / Mn = 1.6), 10 mg of immobilized lipase (Novozym 435) and 12 mg of water are weighed into a 10 mL stainless steel pressure-resistant reaction tube, and then liquefied carbonic acid at 16 MPa. The sample was charged and decomposed in supercritical carbon dioxide using a magnetic stirrer at 40 ° C. for 6 hours and at 16 MPa. After completion of the reaction, the reaction tube was cooled in a dry ice-methanol bath, the gas introduction cock was opened, and the carbon dioxide gas was gradually exhausted. After returning to normal pressure, a small amount of chloroform is added to the decomposition product remaining in the reaction tube, insoluble immobilized lipase is filtered off using Celite, and the solvent is concentrated under reduced pressure using an evaporator from the filtrate, and cyclic dicaprolactone is obtained. Was obtained almost quantitatively. Cyclic dicaprolactone was quantified by GPC and MALDI-TOF MS. In addition, the formation of cyclic dicaprolactone was purified and analyzed by recrystallization from a tetrahydrofuran (THF) solution of the crude product. The results are shown below.
[0045]
Melting point (mp) 113-115 ° C. (literature value 111-113 ° C.). [F. J. et al. Van Natta, J.A. W. Hill, W.M. H. Carothers, J. et al. Am. Chem. Soc. 1934, 56, 455. ]
Infrared spectrum IR (KBr): 2936, 2866 (CH2), 1721 (COO, ester), 1472 cm-1(CH2).1H-NMR (300 MHz, CDClThree): Δ = 1.35-1.75 (m, 12H, CH2ofC-3,3 ', 4,4', 5and5 '), 2.38 (t, J = 6.05 Hz, 4H, CH2ofC-2and2 '), 4.16 (t, J = 5.63 Hz, 4H, CH2ofC-6and6 ').13C-NMR (75 MHz, CDClThree): Δ = 24.6, 28.1 (C-3, 3 ', 4, 4', 5and 5 ', CH2), 34.6 (C-2and2 ', CH2), 63.0 (C-6and6 ', CH2), 173.5 (C-1 and 1 ', C = 0).
Elemental analysis value C12H20OFour(228.3): Calculated value C63.13; H8.83; Theoretical value C63.12; H8.79.
[0046]
Similarly, the change in the yield of cyclic dicaprolactone (DCL) when the pressure of supercritical carbon dioxide is changed is shown in FIG. From FIG. 1, the yield of DCL increased with increasing pressure, reached the maximum value at 16 MPa, and no effect was observed even when the pressure was increased further. In this range of pressure, only the content of DCL was changed by changing the pressure, and it was almost quantitatively converted into an oligomer mainly composed of a cyclic product containing cyclic dicaprolactone.
[0047]
FIG. 2 shows the relationship between the temperature when the reaction is carried out at 16 MPa and the yield of cyclic dicaprolacun (DCL) (reaction for 6 hours).
From FIG. 2, it was found that the maximum yield of DCL can be obtained at a reaction temperature of 40 to 50 ° C. At a reaction temperature higher than this, the enzyme activity decreases and the yield also decreases.
The yield of cyclic dicaprolacun (DCL) greatly depends on the amount of water initially added. If the amount of water is extremely large, the amount of linear hydroxy acid is increased by hydrolysis. FIG. 3 shows the relationship between the amount of water in the reaction system and the yield of cyclic dicaprolacun (DCL).
[0048]
Example4
30 mg of poly (butylene adipate) (molecular weight Mw 22,000), 30 mg of immobilized lipase (Novozym 435) and 20 mg of water were weighed into a 10 mL stainless steel pressure-resistant reaction tube, and then filled with liquefied carbonic acid at 16 MPa. Decomposition was performed in carbon using a magnetic stirrer at 40 ° C. for 6 hours at 16 MPa. After completion of the reaction, the reaction tube was cooled in a dry ice-methanol bath, the gas introduction cock was opened, and the carbon dioxide gas was gradually exhausted. After returning to normal pressure, a small amount of chloroform is added to the decomposition product remaining in the reaction tube, insoluble immobilized lipase is filtered off using Celite, and the solvent is concentrated under reduced pressure using an evaporator from the filtrate, and cyclic butylene adipate is added. Dimer (in the structural formula (8), L: (CH2)Four, M (CH2)FourA repolymerizable oligomer mainly composed of m = 2) was obtained almost quantitatively. Cyclic butylene adipate dimer was quantified by GPC and MALDI-TOF MS. Moreover, the confirmation of cyclic butylene adipate dimer formation was performed by purifying the crude product by column chromatography.
1H-NMR (300 MHz, CDClThree): Δ (ppm) = 4.12 (—CH2-O-CO-) (4H, m), 2.34 (-CH2-CO-O) (4H, m), 1.73 (-CO-CH2-CH2-CH2-CH2-CO-) (4H, m), 1.68 (-O-CH2-CH2-CH2-CH2-O-) (4H, m).
[0049]
Example5
Example450 mg of cyclic butylene adipate dimer and 5 mg of immobilized lipase (Novozym 435) obtained in the above were weighed into a 10 mL stainless steel pressure-resistant reaction tube, and then filled with liquefied carbon dioxide at 8 MPa, and a magnetic stirrer in supercritical carbon dioxide. Was used for polymerization for 6 hours at 70 ° C. and agitation at 8 MPa. After completion of the reaction, the reaction tube was cooled in a dry ice-methanol bath, the carbon dioxide gas was gradually exhausted, the pressure was returned to normal pressure, a small amount of chloroform was added to the polymer in the reaction tube, and insoluble immobilized lipase was added to celite. And the solvent was concentrated under reduced pressure from the filtrate using an evaporator to obtain poly (butylene adipate) almost quantitatively. When the molecular weight was measured by the GPC method, it was Mw = 52,000.
[0050]
Example6
25 mg of poly (butylene succinate) (molecular weight Mw 99,000), 30 mg of immobilized lipase (Novozym 435) and 12 mg of water were weighed into a 10 mL stainless steel pressure-resistant reaction tube, and then filled with liquefied carbonic acid at 16 MPa. Decomposition was performed in carbon using a magnetic stirrer at 40 ° C. for 6 hours at 16 MPa. After completion of the reaction, the reaction tube was cooled in a dry ice-methanol bath, the gas introduction cock was opened, and the carbon dioxide gas was gradually exhausted. After returning to normal pressure, a small amount of chloroform is added to the decomposition product remaining in the reaction tube, insoluble immobilized lipase is filtered off using Celite, and the solvent is concentrated under reduced pressure using an evaporator from the filtrate. A repolymerizable oligomer having a trimer as a main component was obtained. Cyclic butylene succinate dimer (in the structural formula (8), L: (CH2)2, M (CH2)FourQuantification of m = 2) was performed by GPC and MALDI-TOF MS. Moreover, the confirmation of cyclic | annular butylene succinate dimer production | generation confirmed the crude product by column chromatography, and analyzed.
1H-NMR (300 MHz, CDClThree): Δ (ppm) = 4.11 (—CH2-O-CO-) (4H, m), 2.63 (-CH2-CO-O) (4H, m), 1.71 (-O-CH2-CH2-CH2-CH2-O-) (4H, m).
[0051]
【The invention's effect】
The depolymerization method and polymerization method of the present invention are supercritical.carbon dioxideIs used as a reaction solvent, the reaction solvent can be easily released out of the system by simply returning the system pressure to normal pressure after the reaction, and the product can be easily separated from the system. It is also possible to recover and reuse the released reaction solvent.MoreEven if the solvent leaks out of the reaction system, there is no possibility of contaminating the environment.
Furthermore, the depolymerization and polymerization reaction efficiency is comparable to the depolymerization method and polymerization method using ordinary organic solvents.LipaseIn the case of the depolymerization reaction using, the time required for 100% depolymerization of the polymer is slightly longer than when toluene is used, but is significantly shorter than when acetonitrile is used.
In addition, the present inventionLipaseThe depolymerization method and the polymerization method using a simple one-pot operation may be used, and the reaction conditions are mild and low energy consumption. Furthermore, the oligomer and monomer obtained by depolymerization can be regenerated to the original polymer by repolymerization. And used to perform depolymerization or polymerizationLipaseCan be recovered and used repeatedly, with the advantage that there is virtually no decrease in enzymatic activity.
Therefore, according to the present invention, it has become possible to construct a system for utilizing a polymer material that is environmentally acceptable and that can completely reuse carbon resources.
[Brief description of the drawings]
FIG. 1 Example32 is a graph showing the relationship between the pressure of supercritical carbon dioxide and the yield of cyclic dicaprolactone.
FIG. 2 Example3Is a graph showing the relationship between the reaction temperature and the yield of cyclic dicaprolactone.
FIG. 3 Example3Is a graph showing the relationship between the water content in the reaction system and the yield of cyclic dicaprolactone.
Claims (3)
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| US7396667B2 (en) | 2002-08-05 | 2008-07-08 | Keio University | Enzymatic depolymerization process of polylactic acid, and producing process of polylactic acid using depolymerization product |
| JP2005082710A (en) * | 2003-09-09 | 2005-03-31 | Keio Gijuku | Method for continuous depolymerization of polyester, polycarbonate or polylactic acid with supercritical fluid and continuous depolymerization apparatus |
| US7365149B2 (en) | 2005-12-12 | 2008-04-29 | Hans-Peter Brack | Equipment cleaning in the manufacture of polycarbonates |
| EA016528B1 (en) | 2007-03-19 | 2012-05-30 | Зюд-Хеми Аг | Generation of chemical building blocks from plant biomass by selective depolymerization |
| JP5644405B2 (en) | 2010-11-18 | 2014-12-24 | 株式会社リコー | toner |
| EP3441423A1 (en) * | 2012-11-20 | 2019-02-13 | Carbios | Method for recycling plastic products |
| EP3143075B1 (en) | 2014-05-16 | 2022-05-18 | Carbios | Process of recycling mixed pet plastic articles |
| EP3209771B1 (en) | 2014-10-21 | 2020-10-14 | Carbios | Polypeptide having a polyester degrading activity and uses thereof |
| US10626242B2 (en) | 2014-12-19 | 2020-04-21 | Carbios | Plastic compound and preparation process |
| US10508269B2 (en) | 2015-03-13 | 2019-12-17 | Carbios | Polypeptide having a polyester degrading activity and uses thereof |
| CN107709457B (en) | 2015-06-12 | 2021-05-25 | 卡比奥斯公司 | Biodegradable polyester composition and use thereof |
| EP3394264A1 (en) | 2015-12-21 | 2018-10-31 | Carbios | Recombinant yeast cells producing polylactic acid and uses thereof |
| EP3458508A1 (en) | 2016-05-19 | 2019-03-27 | Carbios | A process for degrading plastic products |
| JP2024099501A (en) * | 2023-01-12 | 2024-07-25 | ダイキン工業株式会社 | Composite Materials |
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