CN1583819A - Synthesis of polylactate in supercrilical fluid of CO2 - Google Patents

Synthesis of polylactate in supercrilical fluid of CO2 Download PDF

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Publication number
CN1583819A
CN1583819A CNA2004100251650A CN200410025165A CN1583819A CN 1583819 A CN1583819 A CN 1583819A CN A2004100251650 A CNA2004100251650 A CN A2004100251650A CN 200410025165 A CN200410025165 A CN 200410025165A CN 1583819 A CN1583819 A CN 1583819A
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lactide
supercritical
polylactic acid
fluid
synthesizing polylactic
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CN1241967C (en
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周贤爵
李进
邵惠丽
胡学超
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Donghua University
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    • 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

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Abstract

A synthesis of polylactic acid in super-critical CO2 fluids iscarried out by: adjusting mono-lactide' concentration in a reaction kettle, catalyst and cosolving reagent and its concentration, adjusting reaction temperature, CO2 pressure, reaction time, CO2 purity etc. conditions, to obtain polylactic acid with different molecular weights, and extracting and removing the non-reacted monomers, catalysts and cosolving reagents etc. low molecular weight substances with super-critical CO2 after reaction. The polylactic acid is obtained without post treatment and direct post processing. This invention has advantages of without pollution for products and environment, saving post treatment works, only through depressing operation to realize separating for products and CO2 solvent. It meets demands of current green world environmental protection and saves resources.

Description

A kind of at supercritical CO 2The method of synthesizing polylactic acid in the fluid
Technical field
The invention belongs to technical field of polymer materials, relate in particular to a kind of at supercritical CO 2The method of synthesizing polylactic acid in the fluid.
Background technology
In recent years, at global environment and petroleum resources problem, people urgently wish to develop a kind of from the biological degradation polyalcohol material of return to the nature fully again naturally.It with the plant resources poly(lactic acid) of raw material and multipolymer thereof this class biology novel material of degrading fully just, also have excellent biological compatibility and Bioabsorbable simultaneously, it is used and has related to fields such as medical material, food product pack, agricultural film and filamentary material.Especially the research of medical biodegradable material is paid attention to most, and succeeds in clinical application.
Poly(lactic acid) is normal to adopt two kinds of methods synthetic: (1) direct method is directly prepared by condensation by lactic acid; (2) indirect method is from the lactic acid synthesis of cyclic lactide and the method for carrying out ring-opening polymerization immediately.The direct synthetic technology of poly(lactic acid) sees U.S.Pat5543494, U.S.Pat5075115, and U.S.Pat2396994, U.S.Pat2438208 etc., because polycondensation and depolymerization reaction can not independently be controlled, the gained molecular weight generally is lower than 10,000.The high-molecular weight polymerisate often adopts body fusion ring-opening polymerization method to synthesize in particular as biological engineering material.In the past, the ring-opening polymerization method was that lactide and polymerizing catalyst are mixed, and was heated to 180-220 ℃ and carried out (with reference to special public clear 56-14688 communique), for the ease of control, reduce polymerization temperature, also the someone adopt solution polymerization method (referring to U.S.Pat6376643, U.S.Pat5770683 and Colloid Poly, .Sci., 2002,280,107-115), the use of conventional organic solvents has not only limited the use range of product, and does not meet " greenization " technological process principle.And particularly body fusion ring-opening polymerization of mass polymerization is usually carried out on the fusing point of poly(lactic acid), and polymerization temperature is higher, is difficult to avoid side reaction to take place, and can cause polymerisate racemization, band look, influences the optical activity and the final use properties of product.No matter be ring-opening polymerization or direct polymerization, final polymerisate often all will adopt organic solvent to separate purification (referring to CN1175601, CN1357390, CN1325913, U.S.Pat6376643), remove lower-molecular substances such as the catalyzer in the product, last reaction monomers and byproduct of reaction,, cause the secondary pollution of polymerization product to satisfy the product application needs.
As a kind of friendly process process, supercutical fluid is supercritical CO especially 2(SC-CO 2) nontoxic with it, do not fire, cheap being easy to get and plurality of advantages such as moderate critical condition and be widely used in the synthetic and processing of polymkeric substance.Because at the above carbonic acid gas of stagnation point is a kind of potential optimum solvent of similar varsol, can replace conventional organic solvents to dissolve most of small molecules organic compound and polymer monomer, make polyreaction under the supercritical state both have the advantage of solution polymerization and do not have the problem of organic solvent contaminate environment and product.
Synthetic for poly(lactic acid) equitemperature susceptibility biological degradation novel material, SC-CO 2Polymerization technique is environmental protection not only, and can reduce polymerization temperature significantly, guarantee the optical activity of polymerisate, simultaneously after polyreaction finishes, can also utilize supercritical co that the solvability of lower-molecular substances such as intact monomer (rac-Lactide) of unreacted and catalyzer is come purification by liquid extraction poly(lactic acid) product, polyreaction and purifying are finished in same process.
Because the restriction of supercritical co solubleness, molecular weight promptly begins precipitation greater than 2000 poly(lactic acid), is difficult to obtain the high-molecular weight polymerisate.By add surfactant materials such as unbodied silicon, fluorine cpd can improve the supercritical co dissolving power, but these tensio-active agents are often more expensive, and on the other hand, it usually combines with polymerisate, not easily separated, may cause the secondary pollution of product.
Summary of the invention
It is a kind of at supercritical CO that problem to be solved by this invention is to provide 2The method of synthesizing polylactic acid in the fluid is to overcome polymerization temperature height in the prior art, big, the secondary pollution shortcoming heavily of side reaction.
The invention provides a kind of at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that this method comprises the steps:
A. with the reactor cleaning, drying, the CO of the 3 molecular sieve dryings of stimulating the menstrual flow 2Gas, 3 molecular sieves activate 24 hours down at 320 ℃;
B. add monomer rac-Lactide, catalyzer and cosolvent, wherein the mol ratio of monomer rac-Lactide and catalyzer is 100～20000: 1, and the mol ratio of cosolvent and monomer rac-Lactide is 0～0.5: 1, and monomer rac-Lactide consumption is 0.1～0.8mol/L in the reactor;
C. sealed reactor heats, and when making temperature reach 70～100 ℃, and the control reacting kettle inner pressure is 10～45Mpa;
D. start agitator, reacted 10～60 hours;
E. logical water coolant, and controlled temperature continues to stir logical exsiccant CO at 40～60 ℃ 2Gas, flow control is at 200～1000 milliliters/hour, and pressure-controlling is at 15～25Mpa, supercritical extraction 4～10 hours;
F. logical water coolant makes reactor reduce to room temperature, and is depressurized to normal pressure, takes out product, is poly(lactic acid).
Wherein said monomer rac-Lactide is a kind of in levorotatory lactide, dextrorotation rac-Lactide, rac-lactide or the Study of Meso-Lactide and more than one.
Described monomer rac-Lactide is a levorotatory lactide.
Described catalyzer is a tin organic compound.
Described tin organic compound is a kind of in stannous iso caprylate or the dibutyl dimethoxy tin.
Described cosolvent is a kind of in acetone, tetrahydrofuran (THF), ether, toluene, dimethylbenzene, hexafluoroisopropanol, chloroform or the Chlorofluorocarbons (CFCs) and more than one.
Described cosolvent is a kind of in acetone, tetrahydrofuran (THF) or the ether and more than one.
Described cosolvent is acetone or ether.
Described cosolvent is an acetone.
The mol ratio of described catalyzer and monomer rac-Lactide is 200～1000: 1, the mol ratio 0.02～0.30: 1 of cosolvent and monomer rac-Lactide, and monomer rac-Lactide concentration is 0.4～0.6mol/L.
The mol ratio of described catalyzer and monomer rac-Lactide is 300～700: 1, the mol ratio 0.05～0.2: 1 of cosolvent and monomer rac-Lactide.
Temperature described in the step C is 70～90 ℃, and reacting kettle inner pressure is 20～30Mpa.
Temperature described in the step C is 80～90 ℃.
Reaction times described in the step D is 20～48 hours.
Reaction times described in the step D is 20～36 hours.
Aforesaid method synthetic polylactic acid molecule amount and molecular weight distribution can adopt the GPC method to measure.The legislate structure of polymkeric substance and optical activity are used 13C NMR and 1H NMR.The thermal characteristics of polymkeric substance and degree of crystallinity can be measured with DSC.The purity of supercritical extraction post polymerization thing can with FTIR and 1H NMR checking and mensuration.
The present invention adopts supercritical carbon dioxide fluid as polymerisation medium, has realized the ring-opening polymerization of rac-Lactide under lower temperature, finds that after tested the weight average molecular mass of institute's synthetic poly(lactic acid) product is greatly about 1 * 10 4～1.2 * 10 5, relative molecular mass dispersion index great majority are about 2.0.Polymerization is after the poly(lactic acid) product usefulness of supercritical carbon dioxide extraction gained 1H NMR can not detect the existence of lower-molecular substances such as rac-Lactide, catalyzer., use during with the L-rac-Lactide as polymerization single polymerization monomer 13C NMR and 1H NMR almost detects less than racemization and takes place.
After adding cosolvent polymerization end, can be separated with catalyzer, intact monomer and other lower-molecular substance of unreacted, do not influence degree of purity of production by the mode of supercritical extraction.
As shown from the above technical solution, ring-opening polymerization in the method supercritical carbon dioxide fluid for preparing poly(lactic acid) and multipolymer thereof provided by the invention, compare with the body melt polymerization with traditional solvent polymeric, the environmental protection more of lactic acid polymerizes in the supercritical CO 2 medium, utilize synthetic poly(lactic acid) of the present invention not need to carry out again any aftertreatment, just can directly be used for post-treatment.This reaction process neither can be brought pollution to product and environment, has saved a series of postprocessing working procedures again, only needs just can realize product and CO by decompression operation 2The separation of solvent.Also can utilize supercritical CO after the reaction 2Unreacted intact monomer, catalyzer and cosolvent are removed in extraction.Fully adapt to world today environmental protection, saved the requirement of resource.
Specific embodiment
The present invention will further describe with following example, but scope of the present invention is not limited to the content of these examples.
Embodiment 1
A. with the reactor cleaning, drying, the CO of the 3 molecular sieve dryings of stimulating the menstrual flow 2Gas;
B. adding concentration is 0.25mol/L levorotatory lactide, catalyzer stannous iso caprylate and cosolvent, and wherein the mol ratio of levorotatory lactide and stannous iso caprylate is 1000: 1, and the mol ratio of cosolvent and levorotatory lactide is 0: 1;
C. sealed reactor heats, and when making temperature reach 85 ℃, and the control reacting kettle inner pressure is 25Mpa;
D. start agitator, reacted 24 hours;
E. logical water coolant, and controlled temperature continues to stir logical exsiccant CO at 40 ℃ 2Gas, flow control is at 1000 milliliters/hour, and pressure-controlling is at 20Mpa, supercritical extraction 6 hours;
F. logical water coolant makes reactor reduce to room temperature, and is depressurized to normal pressure, takes out product, is poly(lactic acid).
The weight-average molecular weight M of product wBe 43000, molecular weight distribution PDI is 1.81.
Embodiment 2
The concentration of levorotatory lactide is 0.5mol/L, and all the other conditions obtain the white powder product, M with embodiment 1 after the polyreaction wBe 75000, PDI is 2.04.
Embodiment 3
Catalyst consumption is 1/500 of a rac-Lactide, and all the other conditions obtain poly(lactic acid), M with embodiment 1 after the polyreaction wBe 74000, PDI is 2.16.
Embodiment 4
Reaction times is 48 hours, and all the other conditions obtain the white powder product, M with embodiment 1 after the polyreaction wBe 54000, PDI is 2.07.
Embodiment 5
Operation and condition are with embodiment 1, and carbon dioxide directly uses not by 3 molecular sieve dryings, obtains the white powder product after the polyreaction, M wBe 1500, PDI is 1.47.
Embodiment 6
Add 0.25mol/L rac-lactide (the organic institute in Chinese Academy of Sciences Shanghai provides for D, L-propyl ester), all the other conditions obtain white micropore powdered product with embodiment 1 after the polyreaction, M wBe 56000, PDI is 1.92.
Embodiment 7
Operation and condition are with embodiment 1, and cosolvent is an acetone, and the mol ratio of acetone and levorotatory lactide is 0.05: 1, obtains white micropore powdered product after the polyreaction, M wBe 88000, PDI is 1.76.
Embodiment 8
Operation and condition are with embodiment 1, and cosolvent is a tetrahydrofuran (THF), and the mol ratio of tetrahydrofuran (THF) and levorotatory lactide is 0.05: 1, obtains white micropore powdered product after the polyreaction, M wBe 48000, PDI is 1.88.
Embodiment 9
Operation and condition are with embodiment 1, and cosolvent is an acetone, and the mol ratio of acetone and levorotatory lactide is 0.15: 1, obtains white micropore powdered product after the polyreaction, M wBe 116000, PDI is 2.28.
Embodiment 10
Operation and condition are with embodiment 1, and cosolvent is an ether, and the mol ratio of ether and levorotatory lactide is 0.05: 1, obtains white micropore powdered product after the polyreaction, M wBe 79000, PDI is 2.15.

Claims (15)

1. one kind at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that this method comprises the steps:
A. with the reactor cleaning, drying, the CO of the 3 molecular sieve dryings of stimulating the menstrual flow 2Gas;
B. add monomer rac-Lactide, catalyzer and cosolvent, wherein the mol ratio of monomer rac-Lactide and catalyzer is 100～20000: 1, and the mol ratio of cosolvent and monomer rac-Lactide is 0～0.5: 1, and monomer rac-Lactide consumption is 0.1～0.8mol/L in the reactor;
C. sealed reactor heats, and when making temperature reach 70～100 ℃, and the control reacting kettle inner pressure is 10～45Mpa;
D. start agitator, reacted 10～60 hours;
E. logical water coolant, and controlled temperature continues to stir logical exsiccant CO at 40～60 ℃ 2Gas, flow control is at 200～1000 milliliters/hour, and pressure-controlling is at 15～25Mpa, supercritical extraction 4～10 hours;
F. logical water coolant makes reactor reduce to room temperature, and is depressurized to normal pressure, takes out product, is poly(lactic acid).
2. according to claim 1 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that described monomer rac-Lactide is a kind of in levorotatory lactide, dextrorotation rac-Lactide, rac-lactide or the Study of Meso-Lactide and more than one.
3. according to claim 2 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that described monomer rac-Lactide is a levorotatory lactide.
4. according to claim 1 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that described catalyzer is a tin organic compound.
5. according to claim 4 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that described tin organic compound is a kind of in stannous iso caprylate or the dibutyl dimethoxy tin.
6. according to claim 1 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that described cosolvent is a kind of in acetone, tetrahydrofuran (THF), ether, toluene, dimethylbenzene, hexafluoroisopropanol, chloroform or the Chlorofluorocarbons (CFCs) and more than one.
7. according to claim 6 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that described cosolvent is a kind of in acetone, tetrahydrofuran (THF) or the ether and more than one.
8. according to claim 7 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that described cosolvent is acetone or ether.
9. according to claim 8 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that described cosolvent is an acetone.
10. according to claim 1 at supercritical CO 2The method of synthesizing polylactic acid in the fluid, the mol ratio that it is characterized in that described catalyzer and monomer rac-Lactide is 200～1000: 1, the mol ratio 0.02～0.30: 1 of cosolvent and monomer rac-Lactide, monomer rac-Lactide concentration is 0.4～0.6mol/L.
11. it is according to claim 10 at supercritical CO 2The method of synthesizing polylactic acid in the fluid, the mol ratio that it is characterized in that described catalyzer and monomer rac-Lactide is 300～700: 1, the mol ratio 0.05～0.2: 1 of cosolvent and monomer rac-Lactide.
12. it is according to claim 1 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that the temperature described in the step C is 70～90 ℃, and reacting kettle inner pressure is 20～30Mpa.
13. it is according to claim 12 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that the temperature described in the step C is 80～90 ℃.
14. it is according to claim 1 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that the reaction times described in the step D is 20～48 hours.
15. it is according to claim 14 at supercritical CO 2The method of synthesizing polylactic acid in the fluid is characterized in that the reaction times described in the step D is 20～36 hours.
CNB2004100251650A 2004-06-15 2004-06-15 Synthesis of polylactate in supercrilical fluid of CO2 Expired - Fee Related CN1241967C (en)

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Cited By (14)

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CN101220138B (en) * 2007-12-13 2010-04-21 上海交通大学 Thermal synthesis production method of solvent of polylactic acid
EP2365016A1 (en) * 2010-03-08 2011-09-14 Ricoh Company, Limited Polymer and method for producing the same
CN103732649A (en) * 2011-08-12 2014-04-16 株式会社理光 Polymer product, polymer compact, polymer compact for medical use, toner, and polymer composition
CN103827168A (en) * 2011-07-29 2014-05-28 株式会社理光 Method for producing polymer
EP2736943A1 (en) * 2011-07-29 2014-06-04 Ricoh Company, Limited Method for producing polymer, device for producing polymer, device for producing complex, and polymer product
CN104114601A (en) * 2012-02-14 2014-10-22 株式会社理光 Method for producing polymer
CN104169323A (en) * 2012-02-14 2014-11-26 株式会社理光 Method for producing polymer and polymer product
CN105073890A (en) * 2013-01-28 2015-11-18 株式会社理光 Polylactic acid composition, and production method and production apparatus of the same
CN105985512A (en) * 2015-02-04 2016-10-05 中国石油化工股份有限公司 Method for producing polylactic acid
CN109111567A (en) * 2017-06-26 2019-01-01 谈骏嵩 Purify the method and device of polybutylene terephthalate (PBT)
CN109320694A (en) * 2018-10-10 2019-02-12 华东理工大学 A kind of preparation method of Stereocomplex body polylactic acid
CN111965874A (en) * 2020-08-07 2020-11-20 Tcl华星光电技术有限公司 Liquid crystal display panel and manufacturing method thereof
CN113512181A (en) * 2021-08-09 2021-10-19 重庆大学 Polylactic acid capable of being processed at low temperature and preparation method thereof
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Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101220138B (en) * 2007-12-13 2010-04-21 上海交通大学 Thermal synthesis production method of solvent of polylactic acid
EP2365016A1 (en) * 2010-03-08 2011-09-14 Ricoh Company, Limited Polymer and method for producing the same
EP2736943A4 (en) * 2011-07-29 2015-04-01 Ricoh Co Ltd Method for producing polymer, device for producing polymer, device for producing complex, and polymer product
CN103827168A (en) * 2011-07-29 2014-05-28 株式会社理光 Method for producing polymer
EP2736943A1 (en) * 2011-07-29 2014-06-04 Ricoh Company, Limited Method for producing polymer, device for producing polymer, device for producing complex, and polymer product
CN103827168B (en) * 2011-07-29 2015-09-16 株式会社理光 Polymers manufacturing method
CN103732649A (en) * 2011-08-12 2014-04-16 株式会社理光 Polymer product, polymer compact, polymer compact for medical use, toner, and polymer composition
CN104169323B (en) * 2012-02-14 2016-03-02 株式会社理光 Polymers manufacturing method and polymer product
CN104114601A (en) * 2012-02-14 2014-10-22 株式会社理光 Method for producing polymer
CN104114601B (en) * 2012-02-14 2016-10-12 株式会社理光 Polymers manufacturing method
CN104169323A (en) * 2012-02-14 2014-11-26 株式会社理光 Method for producing polymer and polymer product
CN105073890A (en) * 2013-01-28 2015-11-18 株式会社理光 Polylactic acid composition, and production method and production apparatus of the same
CN105985512A (en) * 2015-02-04 2016-10-05 中国石油化工股份有限公司 Method for producing polylactic acid
CN109111567B (en) * 2017-06-26 2020-12-15 谈骏嵩 Method and device for purifying polybutylene terephthalate
CN109111567A (en) * 2017-06-26 2019-01-01 谈骏嵩 Purify the method and device of polybutylene terephthalate (PBT)
CN109320694A (en) * 2018-10-10 2019-02-12 华东理工大学 A kind of preparation method of Stereocomplex body polylactic acid
CN111965874A (en) * 2020-08-07 2020-11-20 Tcl华星光电技术有限公司 Liquid crystal display panel and manufacturing method thereof
CN111965874B (en) * 2020-08-07 2023-12-29 Tcl华星光电技术有限公司 Manufacturing method of liquid crystal display panel and liquid crystal display panel
CN113512181A (en) * 2021-08-09 2021-10-19 重庆大学 Polylactic acid capable of being processed at low temperature and preparation method thereof
CN113512181B (en) * 2021-08-09 2022-08-12 重庆大学 Polylactic acid capable of being processed at low temperature and preparation method thereof
CN116606423A (en) * 2023-06-20 2023-08-18 扬州惠通生物新材料有限公司 Preparation method of polylactic acid and copolymer thereof for in vivo degradation control
CN116606423B (en) * 2023-06-20 2024-05-03 扬州惠通生物新材料有限公司 Preparation method of polylactic acid and copolymer thereof for in vivo degradation control

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