CN100343246C - Method for recrystallizing lactide - Google Patents
Method for recrystallizing lactide Download PDFInfo
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- CN100343246C CN100343246C CNB2005100948452A CN200510094845A CN100343246C CN 100343246 C CN100343246 C CN 100343246C CN B2005100948452 A CNB2005100948452 A CN B2005100948452A CN 200510094845 A CN200510094845 A CN 200510094845A CN 100343246 C CN100343246 C CN 100343246C
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- Prior art keywords
- lactide
- rac
- ethyl acetate
- crystallization
- crystallization time
- Prior art date
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- JJTUDXZGHPGLLC-UHFFFAOYSA-N lactide Chemical compound CC1OC(=O)C(C)OC1=O JJTUDXZGHPGLLC-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 25
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims abstract description 54
- 238000002425 crystallisation Methods 0.000 claims abstract description 23
- 230000008025 crystallization Effects 0.000 claims abstract description 23
- 238000001953 recrystallisation Methods 0.000 claims abstract description 13
- 239000013078 crystal Substances 0.000 claims description 10
- 239000002904 solvent Substances 0.000 abstract description 4
- 238000001914 filtration Methods 0.000 abstract description 2
- 238000010438 heat treatment Methods 0.000 abstract 1
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 12
- -1 cyclic ester Chemical class 0.000 description 7
- 239000004310 lactic acid Substances 0.000 description 7
- 229920000747 poly(lactic acid) Polymers 0.000 description 7
- 235000014655 lactic acid Nutrition 0.000 description 6
- 238000002844 melting Methods 0.000 description 6
- 230000008018 melting Effects 0.000 description 6
- 239000012535 impurity Substances 0.000 description 5
- 230000007062 hydrolysis Effects 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- 239000004626 polylactic acid Substances 0.000 description 4
- JVTAAEKCZFNVCJ-REOHCLBHSA-N L-lactic acid Chemical group C[C@H](O)C(O)=O JVTAAEKCZFNVCJ-REOHCLBHSA-N 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 238000001291 vacuum drying Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- JVTAAEKCZFNVCJ-UWTATZPHSA-N D-lactic acid Chemical group C[C@@H](O)C(O)=O JVTAAEKCZFNVCJ-UWTATZPHSA-N 0.000 description 2
- 150000002148 esters Chemical class 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- JJTUDXZGHPGLLC-ZXZARUISSA-N (3r,6s)-3,6-dimethyl-1,4-dioxane-2,5-dione Chemical compound C[C@H]1OC(=O)[C@H](C)OC1=O JJTUDXZGHPGLLC-ZXZARUISSA-N 0.000 description 1
- RKDVKSZUMVYZHH-UHFFFAOYSA-N 1,4-dioxane-2,5-dione Chemical compound O=C1COC(=O)CO1 RKDVKSZUMVYZHH-UHFFFAOYSA-N 0.000 description 1
- MNKRTDOUBUSQHX-UHFFFAOYSA-N 2,4-dihydroxy-2-methyl-3-oxopentanoic acid Chemical compound CC(O)C(=O)C(C)(O)C(O)=O MNKRTDOUBUSQHX-UHFFFAOYSA-N 0.000 description 1
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical class CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 235000011089 carbon dioxide Nutrition 0.000 description 1
- JYYOBHFYCIDXHH-UHFFFAOYSA-N carbonic acid;hydrate Chemical compound O.OC(O)=O JYYOBHFYCIDXHH-UHFFFAOYSA-N 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000000539 dimer Substances 0.000 description 1
- 238000000855 fermentation Methods 0.000 description 1
- 230000004151 fermentation Effects 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 239000005457 ice water Substances 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 230000035800 maturation Effects 0.000 description 1
- 230000002906 microbiologic effect Effects 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000007151 ring opening polymerisation reaction Methods 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 239000002407 tissue scaffold Substances 0.000 description 1
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Heterocyclic Compounds That Contain Two Or More Ring Oxygen Atoms (AREA)
Abstract
The invention relates to a method for recrystallizing lactide by taking ethyl acetate as a solvent, which comprises the following steps: lactide is dissolved in ethyl acetate under heating, and after the solution is cooled and crystallized, the crystalline product is obtained by filtration. The invention is characterized in that: the concentration of the ethyl acetate solution of lactide, as well as the crystallization time of the solutions of different concentrations, were controlled. The invention can improve the quality of the crystallized product and improve the recrystallization efficiency.
Description
Technical field
The present invention relates to a kind of purification process of cyclic ester class organic compound.Specifically, a kind ofly exactly make impure rac-Lactide, reach the method for purifying by the crystallization control time being in the recrystallization process of solvent with the ethyl acetate.
Background technology
Rac-Lactide is a kind of cyclic ester that is generated by two molecule lactic acid, has four kinds of forms: the L-rac-Lactide that two molecule L-lactic acid forms; The D-rac-Lactide that two molecule D-lactic acid form; The Study of Meso-Lactide that a part L-lactic acid and a part D-lactic acid form; And the rac-lactide of L-rac-Lactide and the formation of D-rac-Lactide.Rac-Lactide is a kind of important compound that can be used for preparing poly(lactic acid) and multipolymer thereof.
As everyone knows, poly(lactic acid) and multipolymer thereof are as Biodegradable material, and have two big outstanding advantages: its raw material---lactic acid can be obtained by fermentation, belongs to renewable resources; Its finished product can be become carbonic acid gas and water by microbiological degradation, reach degraded fully, can not produce environment and pollute.Therefore, the research of relevant polylactic acid-based material causes extensive concern.
High molecular weight polylactic acid is normally obtained by highly purified rac-Lactide ring-opening polymerization.Usually, rac-Lactide by aqueous lactic acid through low molecular weight as intermediate, obtain by the cracked method again.Patent CN1212343, CN1369490, AU2003231482, DE3232103, DE3708915, FR2843390, JP63101378, JP2004149418, US1095205, US5053522, US2002132967 etc. have introduced the building-up process of rac-Lactide.
In the rac-Lactide that above-mentioned patented method obtains, also contain impurity (rac-Lactide that hereinafter will contain these impurity is called impure rac-Lactide) such as a small amount of lactic acid monomer, lactic acid dipolymer (lactyllactic acid) and water.
Contained above-mentioned impurity can have a negative impact to the polyreaction of rac-Lactide: the existence of water can make the rac-Lactide hydrolysis obtain lactic acid, and can make polylactic acid molecule chain hydrolytic cleavage; The existence of acid such as lactic acid and dimer thereof can make the polylactic acid molecule chain be degraded etc. because of acidolysis.Therefore, impure rac-Lactide need be through purifying to remove the impurity that it contains.
The purification process of impure rac-Lactide generally has evaporation method of air aided, hydrolysis method and recrystallization method etc.
Evaporation method of air aided can make such as rac-Lactide or glycollide or and composition thereof cyclic ester be separated with impurity as the steam component in the air-flow.Relevant patent has AU2003295252, US5274073, US6277951 etc.But evaporation method of air aided sepn process complexity, and yield is generally not high.
Thereby hydrolysis method is a kind of method that mesoisomer obtains the high-optical-purity rac-Lactide of removing from impure rac-Lactide, and relevant patent has CN1112559, JP10025288, US5502215 etc.But after the hydrolysis treatment, generally still need recrystallization to be further purified.
And recrystallization method is few because of its operation steps, technology is used comparatively extensive than maturation.Patent CN1488628, FR2843390, WO9315069 etc. introduce recrystallization method purifying rac-Lactide.But the research for recrystallization method purifying rac-Lactide mostly is choice of Solvent greatly at present, adopt ethyl acetate, JP10279577 to adopt lower member ester class, US6313319 to use alcohols, JP6279435 application lower alcohol, ketone, ester class or its mixture etc. as patent US4727163, CN1583740, and the influence factor of lactide recrystallization technology is not studied.
This patent finds that rac-Lactide adopts different crystallization times when a certain solvent and a certain concentration, and the yield of its recrystallized product and purity have very big difference, and also influential to production efficiency, but this point does not cause people's attention.For example Japanese Patent JP7118259 is when describing the method for recrystallization, crystallizing system is cooled to the temperature that sets after, filter immediately and obtain crystal, its yield has only 50～52%, one of its reason may be crystallization time too short due to.Equally, document Bioresorbable Electrospun Tissue Scaffolds of Poly (ethylene glycol-b-lactide) Copolymers forBone Tissue Engineering one literary composition (Anand Shreyans Badami, Richmond:Virginia Polytechnic Instituteand State University, 2004) in crystallizing system placed that 1 hour after-filtration obtains the rac-Lactide crystal in the ice-water bath, also have the too short problem of crystallization time in this technology.And at document " the purification process research of the research of Biodegradable Polylactide (II) lactide monomer " (Heilongjiang University's natural science journal, 1998,15 (1): 110～113), crystallization time is decided to be 24 hours, this makes that again crystallization time is long, product purity and yield are descended, more prolonged the production cycle greatly.
The present invention particularly points out: crystallization time is too short, can cause product yield low; And crystallization time is long, can cause product purity poor, and productivity reduces.By control, can effectively improve the yield and the purity of crystallized product, and enhance productivity the crystallization time of different concns solution in the recrystallization process.
Summary of the invention
Purpose of the present invention promptly for the rac-Lactide ethyl acetate solution of different concns, by the control to crystallization time, makes product obtain better purity and crystallization yield.
Purpose of the present invention can reach by following measure:
A is dissolved in ethyl acetate with impure rac-Lactide under 60 ℃～75 ℃, obtain certain density solution;
B with solution left standstill for some time, makes the rac-Lactide crystallization under 0 ℃～30 ℃;
C filters and obtains crystal and dry.
In further of the present invention, the mass ratio of rac-Lactide and ethyl acetate is 9: 20～6: 5, and optimum quality ratio is 3: 5～1: 1.
Crystallization time was controlled between 2～8 hours, optimum range 3～5 hours.
Advantage of the present invention: controlled by crystallization time, effectively improve the yield and the purity of crystallized product, and enhance productivity to the rac-Lactide ethyl acetate solution of different concns in the recrystallization process.
Embodiment
Embodiment 1
Add the impure rac-Lactide of 10.0g (through surveying 86 ℃～95 ℃ of melting ranges) in single neck flask, the mass ratio of pressing rac-Lactide and ethyl acetate adds ethyl acetate 22.2g at 9: 20, is heated to 75 ℃ of dissolvings.After the dissolving fully, in 4 ℃ of refrigerators, left standstill crystallization 3 hours, filter and obtain crystal and vacuum-drying.Dry back crystal mass 7.2g, yield 72.0%, surveying its melting range is 93 ℃～96 ℃.
Embodiment 2
Add the impure rac-Lactide of 10.0g (through surveying 89 ℃～95 ℃ of melting ranges) in single neck flask, the mass ratio of pressing rac-Lactide and ethyl acetate adds ethyl acetate 13.3g at 3: 4, is heated to 75 ℃ of dissolvings.After the dissolving fully, in 4 ℃ of refrigerators, left standstill crystallization 6 hours, filter and obtain crystal and vacuum-drying.Dry back crystal mass 7.3g, yield 73.0%, surveying its melting range is 94 ℃～96 ℃.
Embodiment 3
Add the impure rac-Lactide of 10.0g (through surveying 85 ℃～95 ℃ of melting ranges) in single neck flask, the mass ratio of pressing rac-Lactide and ethyl acetate adds ethyl acetate 10g at 1: 1, is heated to 75 ℃ of dissolvings.After the dissolving fully, in 4 ℃ of refrigerators, left standstill crystallization 8 hours, filter and obtain crystal and vacuum-drying.Dry back crystal mass 7.4g, yield 74.0%, surveying its melting range is 91 ℃～95 ℃.
Claims (5)
1. the present invention is the method for a kind of crystallization or recrystallization purifying rac-Lactide, and this method comprises:
A is dissolved in ethyl acetate with impure rac-Lactide under 60 ℃～75 ℃, obtain solution;
B is under 0 ℃～30 ℃, and with solution left standstill, the crystallization of chien shih rac-Lactide is separated out during crystallization control;
C filters and obtains crystal and dry.
2. according to the process of claim 1 wherein that the mass ratio of described rac-Lactide of steps A and ethyl acetate is 9: 20～6: 5.
3. according to the method for claim 2, wherein the mass ratio of rac-Lactide and ethyl acetate is 3: 5～1: 1.
4. according to the method for claim 1, the crystallization time that it is characterized in that being controlled is between 2～8 hours.
5. according to the method for claim 4, the crystallization time that it is characterized in that being controlled is between 3～5 hours.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100948452A CN100343246C (en) | 2005-10-17 | 2005-10-17 | Method for recrystallizing lactide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2005100948452A CN100343246C (en) | 2005-10-17 | 2005-10-17 | Method for recrystallizing lactide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1757643A CN1757643A (en) | 2006-04-12 |
| CN100343246C true CN100343246C (en) | 2007-10-17 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2005100948452A Expired - Fee Related CN100343246C (en) | 2005-10-17 | 2005-10-17 | Method for recrystallizing lactide |
Country Status (1)
| Country | Link |
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| CN (1) | CN100343246C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8431725B2 (en) | 2007-03-14 | 2013-04-30 | Niro Process Technology B.V. | Purification of lactide rich streams |
| CN101157680B (en) * | 2007-11-16 | 2010-12-29 | 南京工业大学 | Method for recrystallizing lactide by using double solvents |
| CN106153418A (en) * | 2016-07-22 | 2016-11-23 | 中南大学 | A kind of lactide standard substance and preparation method thereof and detection method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06279435A (en) * | 1993-03-31 | 1994-10-04 | Dainippon Ink & Chem Inc | Purification of lactide |
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2005
- 2005-10-17 CN CNB2005100948452A patent/CN100343246C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06279435A (en) * | 1993-03-31 | 1994-10-04 | Dainippon Ink & Chem Inc | Purification of lactide |
Non-Patent Citations (1)
| Title |
|---|
| 生物降解材料聚丙交酯的研究（II）丙交酯单体的纯化方法研究 张贞浴等，黑龙江大学自然科学学报，第15卷第1期 1998 * |
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| Publication number | Publication date |
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| CN1757643A (en) | 2006-04-12 |
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