CN102863420A - Method for preparing medical lactide - Google Patents
Method for preparing medical lactide Download PDFInfo
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- CN102863420A CN102863420A CN2012103786820A CN201210378682A CN102863420A CN 102863420 A CN102863420 A CN 102863420A CN 2012103786820 A CN2012103786820 A CN 2012103786820A CN 201210378682 A CN201210378682 A CN 201210378682A CN 102863420 A CN102863420 A CN 102863420A
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Abstract
The invention relates to the method for preparing medical lactide. The method includes: adding catalyst and high boiling-point solvent in lactic acid for condensation polymerization to enable the lactic acid to generate lactic-acid oligomer, and adding catalyst in the generated lactic-acid oligomer for depolymerization to obtain the medical lactide. The high boiling-point solvent is added during the condensation polymerization, so that a reaction system during depolymerization cannot become viscous, and is less prone to steam out, carbonize and turn yellow caused by distillation and reduction of lactide, stability of production process, product quality and variability of physical indexes are guaranteed; and the method for preparing medical lactide is high in yield, simple in reaction operation, free of danger, short in production time and beneficial to industrial production, and has quite high economic value.
Description
Technical field
The present invention relates to the preparation field of macromolecular compound, particularly, relate to a kind of method for preparing medical rac-Lactide.
Background technology
Medical rac-Lactide is the important source material of synthesis of medical poly(lactic acid), medical poly-lactic acid material as 21 century the novel green material widely prospect is being arranged aspect the bio-medical material.Poly(lactic acid) is nontoxic, nonirritant, have good biocompatibility, Bioabsorbable and biodegradability, also have the advantages such as physical strength height, stable chemical performance and easy processing, can be used as biomedical material, be used as slow releasing carrier of medication, Srgery grafting material, as: suture, ophthalmology embedded material, bone fracture internal fixation material, and wrapper material and artificial blood vessel and the tissue engineering bracket (such as artificial skin) etc. of extensive wound (especially burn).
And in the synthesis technique of medical poly(lactic acid), the purity of rac-Lactide is extremely important, make poly-lactic acid in high molecular weight, must select the high purity rac-Lactide.Existing patent generally adopts the method for ring-opening polymerization, and high temperature high vacuum cracking lactic acid oligomers prepares rac-Lactide.
Be CN 1616450A such as Chinese patent application 200310107684.7(publication number) a kind of method that catalyzer prepares rac-Lactide that adds is at twice disclosed, its preparation process is:
1, lactic acid and catalyst Z nO are heated in the ratio adding container in 135 ~ 165:1, temperature reaches 100 ℃ and vacuumizes, and increase vacuum tightness slowly heated up in 2 ~ 2.5 hours;
When 2, temperature reaches 135 ~ 155 ℃, add again ZnO and La
2О
3, two mixed catalyst mass ratioes are 3 ~ 5:1, are 1/300 ~ 250/1:1 of lactic acid quality;
3, vacuum tightness is kept 30 ~ 60min when 0.03 ~ 0.04MPa, sloughs moisture, changes receiving flask when not having water to distill;
4, heat up 170 ~ 190 ℃, increase vacuum 0.09 ~ 0.10MPa, receive liquid, be cooled to normal temperature and be the rac-Lactide crystal.
Chinese patent application 200810064553.8(publication number is CN 101585827A) a kind of use D disclosed, the dehydration of Pfansteihl normal pressure, the catalyzer decompression dehydration generates lact-acid oligomer, and then the oligopolymer Pintsch process generates D, the method of L-rac-Lactide, its preparation process is:
1, D, 145 ℃ of normal pressure zeolite dehydrations of Pfansteihl;
2, lact-acid oligomer adds 150 ℃ of boilings of catalyzer (ZnO) 1.5wt% decompression, 2 ~ 3h dehydration;
3,170 ℃ ~ 250 ℃ Pintsch processs of lact-acid oligomer, underpressure distillation under the-0.095Mpa vacuum tightness system obtains rac-Lactide.
And all there is following shortcoming in above patented method:
1, the rac-Lactide that obtains is light yellow or yellow;
2, reactant tails off gradually with the distillation of rac-Lactide and thickness, charing occurs, and causes being difficult for distillation, and productive rate reduces;
3, the rac-Lactide of the rac-Lactide of distillation in early stage and later stage distillation is unstable on physical index, and variability is larger.
Generate in the method for rac-Lactide in existing ring-opening polymerization, as follows about the patented technology of dehydration, polycondensation and depolymerization three-step reaction:
Chinese patent application 200510094947.4(publication number is CN 1951933A) disclose that a kind of polymerization under atmospheric pressure high temperature inert gas is taken resultant of reaction out of, cooling obtains the method for rac-Lactide, its preparation process is:
1, Pfansteihl carries out dehydration reaction under 150 ~ 180 ℃ of vacuum tightness 5000pa ~ 8000pa, obtains lact-acid oligomer;
2,150 ~ 250 ℃ of synthesis under normal pressure of lact-acid oligomer;
3, pass into 200 ~ 500 ℃ of rare gas elementes rac-Lactide that will gasify and take out of, then rac-Lactide is collected in cooling.
There is following shortcoming in this patented method:
1, reactant tails off with the distillation of rac-Lactide and thickness, charing occurs, and causes being difficult for distillation, productive rate reduces;
2, the heating high-temperature gas operation and reclaim dangerous property.
Chinese patent application 200810080194.5(publication number is CN 101434594A) a kind of method of preparing lactide by mixed solvent process is disclosed, its preparation process is:
1, D/L-lactic acid carries out dehydration reaction under 120 ℃;
2, heat up 160 ℃, add 0.7 ~ 0.8% catalyzer (zinc oxide or antimonous oxide), add low boiling point solvent (n-Heptyl alcohol, butanols or amylalcohol) 10 ~ 20%;
3, heat up 220 ℃, add 0.7 ~ 0.8% catalyzer (zinc oxide or antimonous oxide), underpressure distillation produces lactic acid oligomer;
4, the decompression lactic acid oligomer that heats up, 160 ~ 200 ℃, during vacuum 600 ~ 760mm Hg, material is by dark yellow browning look or black, the beginning cracking; Reacted 2 ~ 3 hours temperature to 250 ~ 280 ℃, adds high boiling solvent (hexadecanol or stearyl alcohol) 15 ~ 25%, and underpressure distillation 4 hours obtains rac-Lactide.
There is following shortcoming in this patented method:
1, the rac-Lactide color is yellow;
2, process is complicated, and the production time is long, can't large-scale production.
Therefore, if can develop the preparation method that a place overcomes the rac-Lactide of prior art associated problem, most important for this art.
Summary of the invention
The problem that exists in order to solve prior art the object of the present invention is to provide a kind of method for preparing medical rac-Lactide.
The method of the medical rac-Lactide of preparation provided by the invention comprises: adding catalyzer and high boiling solvent carry out polycondensation in lactic acid, so that lactic acid generates lact-acid oligomer; In the lact-acid oligomer that generates, add catalyzer, carry out depolymerization reaction, obtain medical rac-Lactide.
Wherein, described high boiling solvent is: diethyl phthalate, silicone oil, hexadecanol or stearyl alcohol.Preferred diethyl phthalate.
Wherein, lactic acid is 0.5 ~ 2:1 with the weight ratio of the high boiling solvent that adds, preferred 2:1.
Wherein, the catalyzer that adds in lactic acid is: antimonous oxide, Vanadium Pentoxide in FLAKES, zinc oxide or antimony trifluoride.Preferred antimonous oxide.
Wherein, lactic acid is 800 ~ 1200:1 with the weight ratio that adds catalyzer in lactic acid, preferred 1000:1.
Wherein, the process of polycondensation comprises pre-polymerization and poly-eventually.
Wherein, under the condition of 150 ~ 200 ℃ and 110 ~ 25Kpa through prepolymerization reaction 3 ~ 5 hours.Preferred prepolymerization reaction 4 hours under the condition of 170 ℃ and 30Kpa.This moment tentatively slough between the lactic acid (LA) in conjunction with water, after the dehydration polycondensation by intermolecular hydroxyl and carboxyl, make lactic acid molecules begin polymerization.
Wherein, under the condition of 160 ~ 190 ℃ and 20 ~ 5Kpa, through whole poly-reaction 1.5 ~ 2.5 hours, generate lact-acid oligomer.Preferably eventually poly-reaction 2 hours under the condition of 175 ℃ and 20Kpa.
Wherein, the catalyzer that adds in lact-acid oligomer is: stannous octoate, stannous sulfate, stannous octoate or lactic acid tin.The inferior tin of preferably octanoic acid.
Wherein, lactic acid is 600 ~ 700:1 with the weight ratio that adds catalyzer in lact-acid oligomer, preferred 667:1.
Wherein, through depolymerization reaction, distillation obtains medical rac-Lactide under the condition of 200 ~ 250 ℃ and 10 ~ 3Kpa.Preferably under the condition of 220 ℃ and 3Kpa, carry out depolymerization reaction.
Preparation method of the present invention before carrying out polycondensation, can also comprise lactic acid is carried out dehydration reaction.
Wherein, the process of dehydration reaction comprises: under the condition of 90 ~ 150 ℃ and 200 ~ 300Kpa, and condensation dehydration 2 ~ 4 hours.Optimum condition is: dehydration is 3 hours under 120 ℃ and 200 ~ 250Kpa.
Dehydration of the present invention can be adopted the conventional or disclosed method in this area, also can use the above-mentioned method of the present invention; The latter is so that the present invention is doing on the improved basis prior art, and whole structure is more excellent, the purpose of dehydration be for the back polymerization more complete.
Method provided by the invention, improve on the basis that existing cyclopolymerization generates the method for rac-Lactide, in polycondensation process, add high boiling solvent, make thickness that reaction system can not become because the distillation of rac-Lactide reduces when depolymerization, be difficult for steaming, carbonization, flavescence, guaranteed the stable and quality product of production process, and the variability of physical index.The rac-Lactide that obtains has superiority at material purity and required precision, if the follow-up recrystallization of doing again, number of times can be seldom.And productive rate is higher, and operation is simple, and is not dangerous, and the production time is short, is beneficial to suitability for industrialized production, has very high economic worth.
Embodiment
Following examples are used for explanation the present invention, but are not used for limiting the scope of the invention.
Normal pressure among the present invention refers to 0.1Mpa.
The material that the present invention uses and equipment all can be buied from the market, among related other operating method and the condition routine that is this area select.
Embodiment 1
In reactor, add 50kg Pfansteihl, the air in the replacement reaction kettle (vacuumize-Tong nitrogen, circulate 3 times); Heating medium is oil, makes oil temperature be raised to 120 ℃, slowly is evacuated to 200Kpa, condensation dehydration (having water to prolong to flow out), and water gradually stops after 3 hours;
Logical nitrogen adds 50g antimonous oxide and diethyl phthalate 25kg to the normal pressure draining; Oil temperature is warming up to 170 ℃, continues slowly to be evacuated to 30Kpa, reacts 4 hours; This moment tentatively slough between the lactic acid (LA) in conjunction with water, after the dehydration polycondensation by intermolecular hydroxyl and carboxyl, make lactic acid molecules begin polymerization;
Then logical nitrogen changes heating medium into water to the normal pressure draining, and temperature is controlled at 175 ℃, continues to be evacuated to 20Kpa, refluxes 2 hours, generates lact-acid oligomer;
In reactor, pass at last inert nitrogen gas to normal pressure; discharge the distilled water that produces in the reaction process; add the 75g stannous octoate in the lact-acid oligomer that obtains, heating medium is oil, 220 ℃ of oil temperatures; be evacuated to and distill out rac-Lactide liquid under the 3Kpa; this liquid collecting is in the storage tank of protecting with 75 ℃ of water temperatures, and discharging is separated out throw out again after cooling, i.e. product L-rac-Lactide; the lenticular that is white in color can be used as medical.
Embodiment 2
Other conditions are with embodiment 1, and difference is that raw material adds 50kg D, and Pfansteihl prepares D, the L-rac-Lactide, and lenticular is white in color.
Embodiment 3
Other conditions are with embodiment 1, and difference is that the adding weight ratio is Pfansteihl and the diethyl phthalate of 1:1, prepares the L-rac-Lactide, and lenticular is white in color.
Embodiment 4
Other conditions are with embodiment 1, and difference is that the adding weight ratio is D-ALPHA-Hydroxypropionic acid and the diethyl phthalate of 1:2, prepares the D-rac-Lactide, and lenticular is white in color.
Embodiment 5
Other conditions are with embodiment 1, and difference is to use silicone oil to replace diethyl phthalate, and productive rate is 89%.
Embodiment 6
Other conditions are with embodiment 1, and difference is to use hexadecanol to replace diethyl phthalate, and productive rate is 90%.
Embodiment 7
Other conditions are with embodiment 1, and difference is to use stearyl alcohol to replace diethyl phthalate, and productive rate is 90.5%.
Experimental example
Detect the purity of embodiment 1 ~ 4 prepared each rac-Lactide according to the industry standard of the formulation of Nature Works company, mensuration according to GB FZ/T 50012-2006(Determining terminal carboxy group in PET) detect the end carboxyl value of embodiment 1 ~ 4 prepared each rac-Lactide, they are respectively in twice test of anteroposterior diameter of production process.Comparative result such as following table:
As can be seen from the above table: each rac-Lactide purity that the present invention makes is very high, and end carboxyl value is very low, and preparation time is short, and productive rate is high.
Annotate, twice test refers to before and after its moderate purity and the end carboxyl production process:
Depolymerization process vacuumizes behind the adding stannous octoate, and the rac-Lactide holding tank begins discharging, and sampling detects once; Vacuum is evacuated to 5Kpa ~ 1Kpa, and rac-Lactide is evacuated to the rac-Lactide holding tank fully, and without the material extraction, it is large that vacuum tightness becomes in the raw material reaction tank, i.e. preparation is fully taken a sample and detected once.
" preparation time " in the form refers to prepare the completely time.
Comparative Examples
Comparative group 1: according to the embodiment two of patent application CN 1616450A Instructions Page 2, (see its step (1) and step (3)) and add the method for catalyzer at twice, and the consumption of lactic raw material is adjusted into 50kg, preparation obtain rac-Lactide.
Comparative group 2: according to the embodiment 3 ~ 6 of patent application CN 101585827A, with D, the consumption of Pfansteihl raw material is adjusted into 50kg, prepares D, the L-rac-Lactide.
Comparative group 3: take the again method through cooling off of resultant of reaction out of according to embodiment 1, the polymerization under atmospheric pressure high temperature inert gas of patent application CN 1951933A, and the consumption of Pfansteihl raw material is narrowed down to 50kg, prepare the L-rac-Lactide.Shortcoming: have uncontrollable factor and certain risk in the operation of gas heating high-temperature gas.
Comparative group 4: according to the mixed solvent method of patent application CN 101434594A embodiment 1, with D, the Pfansteihl raw material is amplified to 50kg, prepares D, the L-rac-Lactide.
According to the method for above-mentioned experimental example, detect purity and the end carboxyl value of each rac-Lactide that above comparative group 1 ~ 4 makes, they are respectively in twice test of anteroposterior diameter of production process.Comparative result such as following table:
Productive rate=distillation discharge water+preparation rac-Lactide+waste material (preparation residue) ÷ lactic acid addition * 100%.
According to the rac-Lactide that embodiment 5 ~ 7 obtains, purity is low than embodiment's 1, holds the carboxyl value than the height of embodiment 1, but is better than comparative group.
As can be seen from the above Examples and Comparative Examples: each rac-Lactide purity, productive rate that the present invention prepares are relatively high; The most key is, product end carboxyl value is lower than the prior art, and has overcome many technical problems of prior art, and stable production process can be used as the production line scale production.
Although, above used general explanation, embodiment and test, the present invention is described in detail, on basis of the present invention, can make some modifications or improvement to it, and this will be apparent to those skilled in the art.Therefore, these modifications or improvements all belong to the scope of protection of present invention without departing from theon the basis of the spirit of the present invention.
Claims (10)
1. method for preparing medical rac-Lactide comprises: add catalyzer and high boiling solvent carries out polycondensation in lactic acid, so that lactic acid generates lact-acid oligomer; In the lact-acid oligomer that generates, add catalyzer, carry out depolymerization reaction, obtain medical rac-Lactide.
2. method according to claim 1 is characterized in that, described high boiling solvent is: diethyl phthalate, silicone oil, hexadecanol or stearyl alcohol.
3. method according to claim 1 and 2 is characterized in that, the weight ratio of lactic acid and high boiling solvent is 0.5 ~ 2:1.
4. method according to claim 1 is characterized in that, the catalyzer that adds in lactic acid is: antimonous oxide, Vanadium Pentoxide in FLAKES, zinc oxide or antimony trifluoride.
5. according to claim 1 or 4 described methods, it is characterized in that lactic acid is 800 ~ 1200:1 with the weight ratio that adds catalyzer in lactic acid.
6. the described method of any one is characterized in that according to claim 1 ~ 5, and the process of polycondensation comprises pre-polymerization and eventually poly-reaction; Under the condition of 150 ~ 200 ℃ and 110 ~ 25Kpa through prepolymerization reaction 3 ~ 5 hours; Under the condition of 160 ~ 190 ℃ and 20 ~ 5Kpa through whole poly-reaction 1.5 ~ 2.5 hours.
7. method according to claim 1 is characterized in that, the catalyzer that adds in lact-acid oligomer is: stannous octoate, stannous sulfate, stannous octoate or lactic acid tin.
8. according to claim 1 or 7 described methods, it is characterized in that lactic acid is 600 ~ 700:1 with the weight ratio that adds catalyzer in lact-acid oligomer.
9. method according to claim 1 is characterized in that, through depolymerization reaction, distillation obtains medical rac-Lactide under the condition of 200 ~ 250 ℃ and 10 ~ 3Kpa.
10. the described method of any one is characterized in that according to claim 1 ~ 9, and the method also comprises before carrying out polycondensation: lactic acid is carried out dehydration reaction.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018176884A1 (en) * | 2017-03-28 | 2018-10-04 | 南京大学 | Method for producing optically pure l-/d-lactide with all-green closed cycle process |
| US10392362B2 (en) * | 2016-02-24 | 2019-08-27 | The Hong Kong Research Institute Of Textiles And Apparel Limited | Method for synthesizing lactide by means of catalysis of lactid acid |
| CN111424059A (en) * | 2020-06-08 | 2020-07-17 | 中粮营养健康研究院有限公司 | Method and system for producing high-yield, high-gloss pure lactide by using biological fermentation technology to prepare lactic acid |
| CN111690124A (en) * | 2020-07-10 | 2020-09-22 | 上海典范医疗科技有限公司 | Medical polylactic acid with controllable molecular weight and preparation method thereof |
| CN111961028A (en) * | 2020-09-23 | 2020-11-20 | 安徽英特力工业工程技术有限公司 | Recrystallization process for refining lactide |
| CN112745293A (en) * | 2019-10-31 | 2021-05-04 | 中国石油化工股份有限公司 | Process method for synthesizing lactide from lactic acid convenient for catalyst recycling |
| CN113603671A (en) * | 2021-08-13 | 2021-11-05 | 山东谷雨春生物科技有限公司 | Method for improving yield of lactide |
| CN115894432A (en) * | 2022-11-24 | 2023-04-04 | 扬州大学 | Medical-grade L-lactide and preparation method thereof |
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| CN101468981A (en) * | 2007-12-25 | 2009-07-01 | 江苏九鼎集团有限公司 | Preparation technique of lactide |
| WO2011089802A1 (en) * | 2010-01-19 | 2011-07-28 | 株式会社クレハ | Method for producing glycolide |
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| CN101468981A (en) * | 2007-12-25 | 2009-07-01 | 江苏九鼎集团有限公司 | Preparation technique of lactide |
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| WO2011089802A1 (en) * | 2010-01-19 | 2011-07-28 | 株式会社クレハ | Method for producing glycolide |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10392362B2 (en) * | 2016-02-24 | 2019-08-27 | The Hong Kong Research Institute Of Textiles And Apparel Limited | Method for synthesizing lactide by means of catalysis of lactid acid |
| WO2018176884A1 (en) * | 2017-03-28 | 2018-10-04 | 南京大学 | Method for producing optically pure l-/d-lactide with all-green closed cycle process |
| CN112745293A (en) * | 2019-10-31 | 2021-05-04 | 中国石油化工股份有限公司 | Process method for synthesizing lactide from lactic acid convenient for catalyst recycling |
| CN112745293B (en) * | 2019-10-31 | 2023-01-10 | 中国石油化工股份有限公司 | Process method for synthesizing lactide from lactic acid convenient for catalyst recycling |
| CN111424059A (en) * | 2020-06-08 | 2020-07-17 | 中粮营养健康研究院有限公司 | Method and system for producing high-yield, high-gloss pure lactide by using biological fermentation technology to prepare lactic acid |
| CN111690124A (en) * | 2020-07-10 | 2020-09-22 | 上海典范医疗科技有限公司 | Medical polylactic acid with controllable molecular weight and preparation method thereof |
| CN111690124B (en) * | 2020-07-10 | 2022-05-17 | 上海典范医疗科技有限公司 | Medical polylactic acid with controllable molecular weight and preparation method thereof |
| CN111961028A (en) * | 2020-09-23 | 2020-11-20 | 安徽英特力工业工程技术有限公司 | Recrystallization process for refining lactide |
| CN113603671A (en) * | 2021-08-13 | 2021-11-05 | 山东谷雨春生物科技有限公司 | Method for improving yield of lactide |
| CN115894432A (en) * | 2022-11-24 | 2023-04-04 | 扬州大学 | Medical-grade L-lactide and preparation method thereof |
| CN115894432B (en) * | 2022-11-24 | 2024-05-28 | 扬州大学 | Medical grade L-lactide and preparation method thereof |
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