WO2003091238A1 - Procede de production de lactide - Google Patents

Procede de production de lactide Download PDF

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Publication number
WO2003091238A1
WO2003091238A1 PCT/JP2003/005244 JP0305244W WO03091238A1 WO 2003091238 A1 WO2003091238 A1 WO 2003091238A1 JP 0305244 W JP0305244 W JP 0305244W WO 03091238 A1 WO03091238 A1 WO 03091238A1
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Prior art keywords
lactide
lactic acid
acid polymer
magnesium
pyrolysis
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PCT/JP2003/005244
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English (en)
Japanese (ja)
Inventor
Haruo Nishida
Yujiang Fan
Yoshihito Shirai
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Haruo Nishida
Yujiang Fan
Yoshihito Shirai
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Application filed by Haruo Nishida, Yujiang Fan, Yoshihito Shirai filed Critical Haruo Nishida
Priority to AU2003231482A priority Critical patent/AU2003231482A1/en
Priority to JP2004501944A priority patent/JP4458422B2/ja
Publication of WO2003091238A1 publication Critical patent/WO2003091238A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D319/00—Heterocyclic compounds containing six-membered rings having two oxygen atoms as the only ring hetero atoms
    • C07D319/10—1,4-Dioxanes; Hydrogenated 1,4-dioxanes
    • C07D319/12—1,4-Dioxanes; Hydrogenated 1,4-dioxanes not condensed with other rings
    • 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
    • C08J11/12—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 dry-heat treatment only
    • 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
    • C08J11/16—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 inorganic material
    • 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
    • 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

Definitions

  • the present invention relates to a method for producing lactide, which is a cyclic dimer of lactic acid, by depolymerizing a lactic acid polymer, and can be used not only for production but also as a chemical recycling technique.
  • lactic acid polymers With the increasing awareness of environmental issues in recent years, the development of biorecyclable and chemically recyclable lactic acid polymers has been actively developed.
  • a method for producing a lactic acid polymer a technique for synthesizing lactide from a lactic acid oligomer by thermal decomposition and then polymerizing the lactide to produce a lactic acid polymer has been well known. In this manufacturing process, maintaining optical purity is important. Because practical lactic acid polymers are transparent, high-strength polymers with a melting point of about 175 ° C, produced by ring-opening polymerization of optically active L-lactide, and a slight decrease in optical activity. This causes a remarkable decrease in the melting point and loses its practicality.
  • the optical purity of lactide is significantly affected not only by the optical purity of lactic acid as a raw material but also by the racemization during the depolymerization of lactic acid oligomers.
  • Noda and Okuyama studied a thermal decomposition catalyst for lactate oligosaccharide under a temperature of 190 to 230 ° C and a reduced pressure of 4 to 5 mmHg.
  • the order of the catalytic activities was Sn>Zn>Ti> Al, and almost the same tendency was reported for the retention of optical purity (Chemical Pharmaceutical. Bulletin, 47, 467 (1999)).
  • 11-209370 discloses a technique for obtaining high-purity lactide by heating to 120 to 230 ° C. in the presence of monobutyltin.
  • Japanese Patent Application Laid-Open No. 11-292,871 discloses a method in which copper chloride is added to a lactic acid oligomer having a molecular weight of 400 to 300, and the mixture is heated to 130 to 260 ° C. And that the racemization of lactide produced by the method is suppressed.
  • Japanese Patent Application Laid-Open No. Hei 10-30691 discloses that steam is blown into a depolymerization reaction system of lactic acid oligomer using a catalyst of Group IA, IIIA, IVA, IIB, and VA. It discloses that racemization is suppressed by heating to 130 to 260 ° C while mixing.
  • tin compounds are both good catalysts in terms of catalytic activity for thermal decomposition and ability to maintain optical purity.
  • it In consideration of chemical recycling, it must generally be applied to higher molecular weight lactic acid polymers, and similar properties are desired in high-temperature and long-time thermal decomposition.
  • the racemization proceeds and the optical purity of the resulting lactide decreases (for example, Polymer Degradation and Stability, 53, 329-342). (1996) and Journal of Applied Polymer Science, 78, 2369-2378 (2000)).
  • Several techniques have been disclosed as methods for suppressing racemization during the depolymerization of this high-molecular-weight lactic acid polymer.
  • Japanese Patent Application Laid-Open No. 9-214141 discloses a method in which a high-boiling alcohol is added in addition to tin as a pyrolysis catalyst, followed by depolymerization after alcohol decomposition. .
  • Japanese Patent Application Laid-Open No. HEI 8-111969 discloses a method for synthesizing lactide from a lactic acid oligomer using ferrous oxide as a catalyst. Furthermore, a method for thermally decomposing a lactic acid oligomer using a hydroxide or alkoxide of an alkali metal, a salt with a carboxylic acid or the like as a catalyst (Japanese Patent Application Laid-Open No. 6-65230) is disclosed. However, all of these methods are methods of lactide synthesis from lactic acid oligomers.
  • Alkali metal compounds and alkaline earth metal compounds generally have many safe compounds and are expected to be used as depolymerization catalysts in place of tin.On the other hand, they are also used as catalysts that are prone to racemization. It is known (JP-A-11-35663). Disclosure of the invention Therefore, a method for efficiently producing lactide with high optical purity from a high-molecular-weight lactic acid polymer is currently desired.
  • An object of the present invention is to provide a catalyst and depolymerization conditions for efficiently converting a lactic acid polymer to lactide having a high optical purity, for example, for chemical recycling of a used high-molecular-weight lactic acid polymer. .
  • the present inventors have conducted intensive studies on the above problems, and as a result, added an alkaline earth metal compound to the lactic acid polymer, and set the temperature at 320 ° C or lower, preferably at 200 ° C or higher and 320 ° C or lower.
  • the inventors have found that by heating in the lower temperature range, lactide can be efficiently converted into lactide having high optical purity, and the present invention has been completed. That is, the present inventors have found the following inventions.
  • a method for producing lactide comprising adding a compound of an alkaline earth metal to a lactic acid polymer and heating the compound to a temperature of from 200 ° C to 320 ° C.
  • the lactic acid polymer may have a weight average molecular weight of 10,000 or more, preferably 30,000 or more, and more preferably 100,000 or more.
  • the alkaline earth metal is preferably calcium or magnesium.
  • the compound of the alkaline earth metal is calcium carbonate, calcium oxide, calcium hydroxide, calcium hydride, magnesium carbonate, magnesium oxide, magnesium hydroxide, and hydrogenated. It is good to be one or more kinds different from the group consisting of magnesium, especially the group consisting of calcium carbonate, calcium oxide, calcium hydroxide, magnesium carbonate, magnesium oxide and magnesium hydroxide.
  • the addition step is preferably performed so that a counter ion of an alkaline earth metal is present around the molecular terminal of the lactic acid polymer.
  • the heating is performed at a temperature of 225 to 320 ° C, preferably 225 to 300 ° C. C, more preferably at 225-250 ° C.
  • the optical purity of the lactic acid polymer is at least 80% e.e., preferably at least 90% e.e., more preferably at least 96% e.e. e.
  • the content of meso-lactide in the lactide obtained is at least It is preferably 1 mol or less, preferably 5 mol or less, and more preferably 2 mol or less.
  • a magnesium compound is added to a lactic acid polymer, and the mixture is heated to a temperature of 320 ° C or less, preferably, 200 to 320 ° C, and 250 to 300 ° C. Manufacturing method of lactide.
  • the lactic acid polymer has a weight average molecular weight of 10,000 or more, preferably 30,000 or more, and more preferably 100,000 or more.
  • the magnesium compound is preferably one or more selected from the group consisting of magnesium carbonate, magnesium oxide, and magnesium hydroxide.
  • the magnesium compound is preferably magnesium oxide.
  • the addition step may be performed by mixing a solid of lactic acid polymer and a solid of magnesium oxide.
  • the addition step is preferably performed so that the magnesium counterion exists around the molecular terminal of the lactic acid polymer.
  • the optical purity of the lactic acid polymer is at least 80% e.e., preferably at least 90% e.e., more preferably at least 96% e.e. e. or more, and the content of meso-lactide in the obtained lactide is 1 O mo 1% or less, preferably 5 mo 1% or less, more preferably 2 mo 1% or less with respect to all lactides. It is good.
  • the lactic acid polymer is a polymer having a lactic acid ester structure as a basic unit.
  • the L-lactic acid ester structure unit is 90% or more, preferably 95% or more of all the units, more preferably 98% or more of the polymer.
  • Components other than the L-lactic acid ester unit include copolymers derived from lactones, cyclic ethers, cyclic amides, and cyclic acid anhydrides that can be copolymerized with D-lactic acid ester unit lactide. It is possible for a component unit to be present.
  • Copolymer components preferably used include lactones such as hydroprolactone, phenolic lacrolactone,] 3-butyrolactone and valaxoxanone; ethylene oxide, propylene oxide, butylene oxide, styrene oxide, styrene oxide, and phenol.
  • Cyclic ethers such as diglycidyl ether, oxetane, and tetrahydrofuran; cyclic amides such as ⁇ - caprolactam; cyclic acid anhydrides such as succinic anhydride and adipic anhydride.
  • an initiator component may be included as a unit that can coexist in the lactic acid polymer.
  • the initiator component alcohols, glycols, glycerols, other polyhydric alcohols, carboxylic acids, polycarboxylic acids, phenols and the like are used.
  • Specific examples of preferred initiator components include: ethylhexyl alcohol, ethylene glycol, propylene glycol, butanediol, polyethylene glycol, polypropylene glycol, polybutyl alcohol, glycerin, and octylic acid. Lactic acid, glycolic acid and the like.
  • an alkaline earth metal is an alkaline earth metal.
  • Known compounds can be used as the alkaline earth metal compound without any particular limitation.
  • Preferably used alkaline earth metal compounds are calcium compounds and magnesium compounds.
  • Specific examples of suitably used alkaline earth metal compounds include calcium carbonate such as calcium carbonate, calcium bicarbonate, calcium oxide, calcium hydroxide, and calcium hydride.
  • Compounds; magnesium compounds such as magnesium carbonate, magnesium bicarbonate, magnesium oxide, magnesium hydroxide, and magnesium hydride; composite metal compounds of calcium and magnesium; and the above calcium compounds and magnesium compounds.
  • a composite compound containing at least 10% by weight or more can be mentioned. Furthermore, two or more of these alkaline earth metal compounds can be used in combination.
  • the method of adding the alkaline earth metal compound can be a known addition method or a mixing method, and is not particularly limited.
  • the alkaline earth metal compound is preferably added so as to be present around the molecular terminal of the lactic acid polymer.
  • a compound of alkaline earth metal or a counterion of alkaline earth metal is preferably present around the molecular terminal of the lactic acid polymer, and an addition method or a mixing method designed as such is used. Is good. More specifically, it is desirable that the alkaline earth metal or a compound thereof is uniformly dispersed in the lactic acid polymer.
  • a method using a finely ground alkaline earth metal or a compound thereof in advance, a method of mixing an alkaline earth metal or a compound thereof with a lactic acid polymer, and then mechanically and / or thermally mixing and dispersing the mixture can be used.
  • suitable addition methods or mixing methods include a melt mixing method, a solution mixing method, a powder mixing and subsequent melt dispersion method, and a master batch method using a conventionally known mixing and dispersing apparatus such as a mixer or an extruder. be able to.
  • the lactic acid polymer has a thermal decomposition mechanism as described below. Samples can be made.
  • the degree of racemization of an alkaline earth metal compound varies depending on its type. For example, comparing a hydroxide with a strong alkalinity as an alkaline earth metal compound with a carbonate that is relatively neutral, the start of thermal decomposition is slow in the case of carbonate, and the carbonate moves to a higher temperature side than the hydroxide. Cheap. As a result, in the case of carbonate, the degree of racemization tends to be higher than that of hydroxide in the temperature range of 200 to 320 ° C. In the case of an oxide of a relatively alkaline alkaline earth metal, such as magnesium oxide, the start of thermal decomposition is slightly higher than that of the hydroxide, but it is 200.
  • magnesium oxide does not promote the decomposition of polylactic acid below 200 ° C due to its low dispersibility in polylactic acid. Since it tends to promote thermal decomposition due to its luka properties, it exhibits an extremely favorable effect of promoting the conversion to lactide with high optical purity while essentially suppressing the racemization reaction at less than 200 ° C.
  • Polylactic acid is considered to have the following thermal decomposition mechanism. That is, as the ripening mechanism, reaction 1 at 200 ° C or lower, reaction 2 at 200 to 320 ° C, and reaction 3 at 320 ° C or higher are considered.
  • Reaction 1 Selective racemization and meso-lactide formation reaction of carboxylic acid anion (one RCOO-one) by asymmetric carbon attack at 200 ° C or lower. In this temperature range, carboxylate acts as the main reactive species, which attacks the asymmetric carbon with a low electron density and produces meso-lactide while causing almost selective racemization by Balden inversion.
  • Reaction 2 Selective L, L-lactide formation reaction at 200-320 ° C by attack of alkanol anion (_RO—) by carbonyl carbon. At 200-320 ° C, alcoholate anion is considered to play a leading role in the decomposition reaction and attack carbonyl carbon to produce lactide without causing racemization. Since reaction 2 is much faster than reaction 1, reaction 1 is considered to be negligible in this temperature range.
  • Reaction 3 Racemization progresses by tautomerization reaction in the polymer main chain at 320 ° C or higher (increase in the production ratio of meso and D, D-lactide). Above 320 ° C, a "keto-enol tautomerization reaction" occurs in the polymer backbone, which is believed to cause racemization with a 50% probability.
  • the addition amount of the alkaline earth metal compound is 50 pp II! ⁇ 10% by weight, more preferably ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ ! It should be in the range of ⁇ 5% by weight.
  • the amount of the above addition is Applied. More specifically, the above addition amount is also applied to the case where a polymer system containing another polymer in addition to the lactic acid polymer is subjected to chemical power recycling.
  • the polyolefin component is melted and reprocessed in the thermal decomposition temperature range of the lactic acid polymer.
  • the alkaline earth metal compound is reworked as it is in the polyolefin component, and can function as a reworked polyolefin filler.
  • the amount of the alkaline earth metal compound can be sufficiently added up to 100% by weight based on the total amount of the lactic acid polymer and the other polymer. After the addition or mixing step, it is subjected to a heating step.
  • the heating step is preferably at a temperature of from 200 to 320 ° C., preferably from 25 to 320 ° C., more preferably from 25 to 300 ° C., most preferably from 22 to 25 ° C. It is better to carry out at ⁇ 250 ° C.
  • This temperature range depends on the molecular weight of the lactic acid polymer, the alkaline earth metal, and the type and shape of the compound. For example, in the case of lactic acid polymers having a low molecular weight, the degree of racemization tends to be low even at relatively low temperatures. The cause of this is not clear yet, but it is considered that the racemization reaction that proceeds at less than 200 ° C. has a lactic acid polymer molecular weight dependency.
  • the above-mentioned temperature range of the present invention can sufficiently bring about the effect of suppressing racemization during the production of lactide.
  • lactic acid polymer into a reactor set to the above-mentioned temperature range, but it is also possible to increase the temperature from a lower temperature to a higher speed. Is selectable. In this case, it is desirable to raise the temperature as quickly as possible, but it is necessary to raise the temperature by at least 30 ° C to suppress racemization.
  • any of a batch type and a continuous type can be used.
  • Extruder is a preferred reactor 1. Autoclave, fluidized bed reactor and the like.
  • the control of the thermal decomposition temperature, the thermal decomposition rate, and the rate of temperature rise are controlled according to the temperature setting of each block of the cylinder, the number of rotations of the screw, the shape of the screw, the type of single screw and twin screw, etc. It is possible to set a suitable temperature range and a temperature rising range in the invention.
  • Each of the above-mentioned reactors has an outlet for removing a gas phase component and an inlet for an inert gas such as nitrogen gas for extruding and replacing Z or the gas phase component.
  • an inert gas such as nitrogen gas for extruding and replacing Z or the gas phase component.
  • a ventro is suitably used as an outlet.
  • the lactide of the present invention can be obtained.
  • a conventionally known method can be used for the evaluation of the racemization of the obtained lactide. For example, if one lactic acid unit undergoes racemization followed by lactide unit elimination, meso-lactide is formed. If two consecutive lactate units undergo racemization and the two lactate units are eliminated as lactide, D, D-lactide is formed. Generally, when the racemization reaction proceeds randomly, meso-lactide is produced as the main reaction product. The ratio of these meso-lactide and D, D-lactide to L, relactide can be confirmed by gas chromatogram analysis.
  • the racemization evaluation is based on the meso-lactide generation rate.
  • the combination can be used as an index. Therefore, the production ratio of meso-lactide in the obtained lactide is 1 Omo 1% or less, preferably 5mo 1% or less, and more preferably 2mo 1% or less.
  • the present invention can provide a method for producing lactide having an effect of suppressing racemization, but the optical purity of lactide obtained depends on the optical purity of polylactic acid used. That is, the higher the optical purity of the polylactic acid used, the higher the optical purity of the lactide obtained. Therefore, if the optical purity of the polylactic acid is at least 80% e.e., preferably at least 90% e.e., more preferably at least 96% e.e. Purity also increases.
  • % e.e The excess amount of one enantiomer present in a mixture consisting of only a pair of enantiomers called enantiomeric excess, expressed as a percentage.
  • Example 1 Synthesis of lactide by thermal decomposition of calcium salt-terminated PLL A in a temperature range of 225 to 250 ° C
  • the pyrolyzer with sampler is the same in the following Examples, Reference Examples and Comparative Examples.
  • PLLA-Ca10 was quickly charged into a pyrolysis oven preheated to 60 ° C while passing an active gas (He). Thereafter, the temperature was raised to 250 ° C at 10 ° C / min.
  • the pyrolysis products in the temperature range of 225-250 ° C were sampled using a sampler and analyzed by gas chromatography-mass spectrometry (GCMS). As a result of analysis, the content of meso-lactide in the total product lactide was 1.3%.
  • the pyrolysis of PLLA-Ca was carried out in the same manner as in Example 1, and the pyrolysis products in a temperature range of 60 to 250 ° C. were sampled using a sampler and analyzed by GCMS. As a result of analysis, the content of meso-lactide was 34.6% of the total lactide produced.
  • the pyrolysis of PLLA-Ca was carried out in the same manner as in Example 1, and the pyrolysis products in the temperature range of 60 to 225 ° C were separated using a sampler and analyzed by GCMS. As a result of analysis, the content of meso-lactide was 92.0% of the total lactide produced.
  • Example 1 The pyrolysis of PLLA-Ca was performed in the same manner as in Example 1, and the pyrolysis products in the temperature range of 60 to 200 ° C. were separated using a sampler and analyzed by GCMS. As a result of the analysis, the content of meso-lactide was 100% of the total lactide produced. From the results of Example 1 and Comparative Examples 1 to 3 above, in the temperature range: 200 to 250 ° C, particularly at 225 to 250 ° C, racemization accompanying thermal decomposition hardly occurs. At temperatures lower than 200 ° C, it can be seen that significant racemization has progressed.
  • Example 2 Synthesis of lactide by isothermal pyrolysis of PL LA-Ca at 250 ° C
  • the content of meso-lactide after decomposition for 10 minutes was 2.3%.
  • Example 2 From the results of Example 2 and Comparative Example 1, the isothermal pyrolysis of PL LA-Ca at 250 ° C clearly showed higher optical purity lactide than when the temperature was raised from 60 ° C to 250 ° C. It can be seen that it can be obtained.
  • the activation energy of the thermal decomposition reaction was 98 kJ Zinol, and it was confirmed that the decomposition reaction proceeded by the primary reaction that selectively generates lactide. Furthermore, it was preheated to 60 ° C while passing inert gas through the above-mentioned pyrolyzer with sampler. 10 ⁇ g of the PLLA-Ca sample was quickly introduced into the pyrolyzer and the temperature was raised in 10 minutes at a heating rate of 10 to completely pyrolyze the PLLA-Ca sample. As a result of analyzing the generated pyrolysis product by GCMS, the content of meso-lactide was 13.3%.
  • the PL LA-Na sample was completely Was pyrolyzed. Analysis of the generated pyrolysis products using GCMS showed that the lactide content was 58.2%, and that the lactate ester (4.7%), 3- to 10-mer (33.2 %), Lactic acid (1.5%), and acrylic acid (0.7%). That is, it was confirmed that the thermal decomposition of PLLA-Na was a decomposition that proceeded randomly within an intermolecular molecule, and was not a reaction for selectively producing lactide.
  • He inert gas
  • the prepared PLLA-Mg 10 ig was quickly charged into a pyrolysis oven heated to 250 ° C. Pyrolysis proceeded quickly, and the pyrolysis products were analyzed by GCMS. As a result, the content of meso-lactide in the case of pyrolysis for 60 seconds was 5.0%.
  • Example 6 Synthesis of lactide by isothermal pyrolysis of P LLA-Mg at 220 ° C
  • the heating temperature of the pyrolysis oven was set to 220 ° C.
  • Isothermal pyrolysis of the prepared magnesium oxide dispersion, PL LA-Mg was performed.
  • the content of meso-lactide after pyrolysis for 60 seconds was 4.2%.
  • Example 7 Synthesis of lactide by isothermal pyrolysis of P LLA-Mg at 200 ° C
  • the heating temperature of the pyrolysis oven was set to 200 ° C. Isothermal pyrolysis of the prepared magnesium oxide-dispersed PLLA-Mg was performed.
  • the content of meso-lactide in the case of performing the pyrolysis for 60 seconds was 5.0%.
  • the pyrolysis product distilled off under reduced pressure was collected in a room temperature trap.
  • the weight of the product distilled off during heating for 4 hours was 11.93 g, and the crude recovery was 59.6%.
  • Analysis of the recovered pyrolysis products using a gas chromatograph showed that the composition of the product was 94.5% for L-lactide, 4.7% for meso-lactide, and D -The lactide content was 0.8%.

Abstract

L'invention concerne un catalyseur ainsi que des conditions de dépolymérisation permettant de convertir efficacement un polymère d'acide lactique en une lactide à grande pureté optique. Ce catalyseur et ces conditions de dépolymérisation sont utilisés dans le but, par exemple, de soumettre un polymère d'acide lactique déchet à poids moléculaire élevé à un recyclage chimique. L'invention concerne également un procédé de production d'une lactide consistant à ajouter un composé d'un métal alcalino-terreux à un polymère d'acide lactique et à chauffer ce mélange à une température inférieure ou égale à 320 °C.
PCT/JP2003/005244 2002-04-25 2003-04-24 Procede de production de lactide WO2003091238A1 (fr)

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AU2003231482A AU2003231482A1 (en) 2002-04-25 2003-04-24 Process for producing lactide
JP2004501944A JP4458422B2 (ja) 2002-04-25 2003-04-24 ラクチドの製造方法

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Cited By (10)

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JP2008201680A (ja) * 2007-02-16 2008-09-04 Teijin Fibers Ltd ポリ乳酸からラクチドを製造する方法
JP2008231048A (ja) * 2007-03-22 2008-10-02 Kyushu Institute Of Technology ラクチドの回収方法
JP2010120915A (ja) * 2008-11-22 2010-06-03 Kitakyushu Foundation For The Advancement Of Industry Science & Technology 難燃化乳酸ポリマー組成物からのラクチドの回収方法
JP2010126491A (ja) * 2008-11-28 2010-06-10 Japan Steel Works Ltd:The ラクチド回収装置および回収方法
JP2010168415A (ja) * 2009-01-20 2010-08-05 Kitakyushu Foundation For The Advancement Of Industry Science & Technology ラクチドの回収装置および回収方法
JP2011507934A (ja) * 2007-12-26 2011-03-10 クタントン・リミテッド α−ヒドロキシ酸の環状ジエステルの製造方法
JP2011162480A (ja) * 2010-02-10 2011-08-25 Kitakyushu Foundation For The Advancement Of Industry Science & Technology ラクチドの回収方法
WO2014086840A1 (fr) 2012-12-04 2014-06-12 Uhde Inventa-Fischer Gmbh Procédé pour une extraction chimique sélective de l'acide lactique depuis un blend de polymères
JP2017132730A (ja) * 2016-01-29 2017-08-03 東洋製罐株式会社 ラクチド回収方法
WO2021181532A1 (fr) * 2020-03-10 2021-09-16 マクセルホールディングス株式会社 Procédé de décomposition d'acide polylactique

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JPH11292871A (ja) * 1998-04-08 1999-10-26 Shimadzu Corp ラセミ化を抑制できるラクチドの製造方法
EP1048665A1 (fr) * 1998-09-25 2000-11-02 Shimadzu Corporation Procede de purification de lactide et lactide destine a des additifs alimentaires

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JP2008201680A (ja) * 2007-02-16 2008-09-04 Teijin Fibers Ltd ポリ乳酸からラクチドを製造する方法
JP2008231048A (ja) * 2007-03-22 2008-10-02 Kyushu Institute Of Technology ラクチドの回収方法
JP2011507934A (ja) * 2007-12-26 2011-03-10 クタントン・リミテッド α−ヒドロキシ酸の環状ジエステルの製造方法
JP2010120915A (ja) * 2008-11-22 2010-06-03 Kitakyushu Foundation For The Advancement Of Industry Science & Technology 難燃化乳酸ポリマー組成物からのラクチドの回収方法
JP2010126491A (ja) * 2008-11-28 2010-06-10 Japan Steel Works Ltd:The ラクチド回収装置および回収方法
JP2010168415A (ja) * 2009-01-20 2010-08-05 Kitakyushu Foundation For The Advancement Of Industry Science & Technology ラクチドの回収装置および回収方法
JP2011162480A (ja) * 2010-02-10 2011-08-25 Kitakyushu Foundation For The Advancement Of Industry Science & Technology ラクチドの回収方法
WO2014086840A1 (fr) 2012-12-04 2014-06-12 Uhde Inventa-Fischer Gmbh Procédé pour une extraction chimique sélective de l'acide lactique depuis un blend de polymères
JP2017132730A (ja) * 2016-01-29 2017-08-03 東洋製罐株式会社 ラクチド回収方法
WO2017130551A1 (fr) * 2016-01-29 2017-08-03 東洋製罐株式会社 Procédé de récupération de lactide
US20190016696A1 (en) * 2016-01-29 2019-01-17 Toyo Seikan Co., Ltd. Method of recovering lactide
US10457661B2 (en) 2016-01-29 2019-10-29 Toyo Seikan Co., Ltd. Method of recovering lactide
WO2021181532A1 (fr) * 2020-03-10 2021-09-16 マクセルホールディングス株式会社 Procédé de décomposition d'acide polylactique
JPWO2021181532A1 (fr) * 2020-03-10 2021-09-16
JP7425181B2 (ja) 2020-03-10 2024-01-30 マクセル株式会社 ポリ乳酸の分解方法

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