CN101157680B - Method for recrystallizing lactide by using double solvents - Google Patents
Method for recrystallizing lactide by using double solvents Download PDFInfo
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- CN101157680B CN101157680B CN2007101355326A CN200710135532A CN101157680B CN 101157680 B CN101157680 B CN 101157680B CN 2007101355326 A CN2007101355326 A CN 2007101355326A CN 200710135532 A CN200710135532 A CN 200710135532A CN 101157680 B CN101157680 B CN 101157680B
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- Prior art keywords
- lactide
- recrystallization
- rac
- ethyl acetate
- ethanol
- 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 49
- 239000002904 solvent Substances 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 17
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 71
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims abstract description 66
- 238000001953 recrystallisation Methods 0.000 claims abstract description 50
- 235000019441 ethanol Nutrition 0.000 claims description 25
- 238000002425 crystallisation Methods 0.000 claims description 10
- 230000008025 crystallization Effects 0.000 claims description 10
- 239000003960 organic solvent Substances 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 2
- 230000001476 alcoholic effect Effects 0.000 claims 1
- 239000013078 crystal Substances 0.000 claims 1
- 229920000747 poly(lactic acid) Polymers 0.000 abstract description 21
- 239000004626 polylactic acid Substances 0.000 abstract description 16
- 230000002349 favourable effect Effects 0.000 abstract 2
- 238000000746 purification Methods 0.000 abstract 2
- 229920000642 polymer Polymers 0.000 abstract 1
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 12
- 238000006116 polymerization reaction Methods 0.000 description 10
- 239000012043 crude product Substances 0.000 description 9
- -1 poly(lactic acid) Polymers 0.000 description 9
- 235000014655 lactic acid Nutrition 0.000 description 6
- 239000004310 lactic acid Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000012535 impurity Substances 0.000 description 3
- 150000002148 esters Chemical class 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 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
- 235000016068 Berberis vulgaris Nutrition 0.000 description 1
- 241000335053 Beta vulgaris Species 0.000 description 1
- 240000008042 Zea mays Species 0.000 description 1
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 1
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 1
- 229920013724 bio-based polymer Polymers 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 235000005822 corn Nutrition 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 239000000539 dimer Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229920006158 high molecular weight polymer Polymers 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000035800 maturation Effects 0.000 description 1
- 230000007483 microbial process Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 229930014626 natural product Natural products 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000007151 ring opening polymerisation reaction Methods 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
Landscapes
- Heterocyclic Compounds That Contain Two Or More Ring Oxygen Atoms (AREA)
- Polyesters Or Polycarbonates (AREA)
Abstract
The invention aims to provide a method for simultaneously obtaining lactide with high yield and high purity by utilizing recrystallization of two solvents. The method is characterized in that two solvents are used for recrystallizing lactide in sequence according to the characteristics that ethanol is favorable for improving the purification yield of lactide but the molecular weight of the obtained polymer is not high, and ethyl acetate is favorable for improving the purity of lactide and can be polymerized to obtain high-molecular-weight polylactic acid but the yield is not high. Compared with the disclosed lactide purification method by recrystallization, the method has the characteristics that the recrystallization product yield is higher, and the high molecular weight polylactic acid is easier to polymerize.
Description
Technical field
The present invention relates to a kind of method of utilizing the recrystallization method purifying to obtain high yield, high purity rac-Lactide.Help improving rac-Lactide purifying yield according to ethanol, ethyl acetate helps improving rac-Lactide purity and the secure satisfactory grades characteristic of son amount poly(lactic acid) of polymerization, uses different organic solvents to reach the best recrystallization effect of rac-Lactide by being controlled at the different recrystallization stage.
Background technology
In the today of advocating sustainableization development, the application of biodegradable polymkeric substance just is being subjected to paying attention to widely.In numerous polyester of being studied up to now, (poly(lactic acid), Polylactic acid are one of a kind of important Biodegradable materials PLA) to polylactide, can be used for fields such as industry, packing business, pharmaceutical sector.The initial feed lactic acid of polylactide extensively derives from natural products such as corn, beet, Mierocrystalline cellulose, can effectively alleviate deficient day by day petroleum resources; The polylactide product can be decomposed into CO through microbial process again fully in physical environment simultaneously
2And H
2O, so polylactide not only has the characteristic of bio-based polymers but also belongs to good biological degradation polyalcohol, is biological renewable polymkeric substance truly.
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, US5463086 etc. have introduced the building-up process of rac-Lactide.
Contain impurity such as lactic acid monomer, lactic acid dipolymer (lactyllactic acid) and water in the crude product of lactide that aforesaid method obtains, these 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, also 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, crude product of lactide need be through purifying to remove its impurity that contains to reach the polymerization requirement.
Solvent recrystallization method purifying crude product of lactide 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, and the recrystallization solvent of selecting for use has following kind: patent US4727163, CN1583740 to adopt ethyl acetate; JP10279577, CN100343246c adopt the lower member ester class; JP6279435 uses lower alcohol, ketone, ester class or its mixture etc.Patent CN100343247c has more optimized the influence to crystallization effect of recrystallization solution concentration in the recrystallization process, recrystallization time.Though most reports select for use ethyl acetate to obtain high-molecular weight polymer as the rac-Lactide polymerizable that solvent obtains, the recrystallization yield is not high; And select ethanol for use is solvent, though the recrystallization yield is higher, the applicant finds that through experiment the rac-Lactide that obtains with ethyl alcohol recrystallization is lower through the polylactic acid molecule amount that polymerization obtains.
But this patent points out to utilize the ethanol recrystallization to obtain high yield rac-Lactide and the rac-Lactide polymerizable of re-crystallizing in ethyl acetate obtains the characteristics of poly-lactic acid in high molecular weight, utilize ethyl alcohol recrystallization to obtain high yield rac-Lactide earlier, obtain to obtain the rac-Lactide of poly-lactic acid in high molecular weight again with re-crystallizing in ethyl acetate, the advantage of two kinds of solvents on yield and polymerization effect can obtain gratifying recrystallization result.
Summary of the invention
Purpose of the present invention promptly is optionally to use different solvents, and crude product of lactide is carried out recrystallization purifying, reaches the best recrystallization effect that high recrystallization yield and polymerizable obtain the rac-Lactide of poly-lactic acid in high molecular weight.
Purpose of the present invention can reach by following steps:
Earlier obtain high yield, obtain high purity with re-crystallizing in ethyl acetate again with ethyl alcohol recrystallization.Wherein, primary recrystallization solvent is an ethanol, and last recrystallization solvent is an ethyl acetate, and does not re-use ethanol carry out recrystallization after the use re-crystallizing in ethyl acetate.
Characteristics of the present invention are to help improving rac-Lactide purifying yield according to ethanol, but the molecular weight of the poly(lactic acid) that obtains is not high, and though ethyl acetate helps improving rac-Lactide purity and polymerization secures satisfactory grades son amount poly(lactic acid), but the characteristic that yield is low is controlled at the best recrystallization effect that the different organic solvent of different recrystallization stages uses reaches rac-Lactide.
Embodiment
Embodiment 1
Get crude product of lactide 50.0g, carry out recrystallization purifying by table 1, the recrystallization yield is: 56.8%; It is 19.6 ten thousand that polymerization obtains the polylactic acid molecule amount.
Table 1
The recrystallization number of times | For the first time | For the second time |
Solvent rac-Lactide and solvent quality proportion crystallization time (h) | Ethanol 7: 10 3 | Ethyl acetate 9: 20 3 |
Embodiment 2
Get crude product of lactide 80.0g, carry out recrystallization purifying by table 2, the recrystallization yield is: 51.0%; It is 22.3 ten thousand that polymerization obtains the polylactic acid molecule amount.
Table 2
The recrystallization number of times | For the first time | For the second time | Three times |
Solvent rac-Lactide and solvent quality proportion crystallization time (h) | Ethanol 7: 10 2 | Ethanol 3: 53 | Ethyl acetate 9: 20 3 |
Embodiment 3
Get crude product of lactide 120.0g, carry out recrystallization purifying by table 3, the recrystallization yield is: 40.1%; It is 33.9 ten thousand that polymerization obtains the polylactic acid molecule amount.
Table 3
The recrystallization number of times | For the first time | For the second time | For the third time | The 4th time |
Solvent rac-Lactide and solvent quality proportion crystallization time (h) | Ethanol 7: 10 3 | Ethanol 3: 53 | Ethyl acetate 3: 45 | Ethyl acetate 3: 43 |
Embodiment 4
Get crude product of lactide 150.0g, carry out recrystallization purifying by table 4, the recrystallization yield is: 45.0%; It is 29.3 ten thousand that polymerization obtains the polylactic acid molecule amount.
Table 4
The recrystallization number of times | For the first time | For the second time | For the third time | The 4th time |
Solvent rac-Lactide and solvent quality proportion crystallization time (h) | Ethanol 7: 10 2 | Ethanol 3: 52 | Ethanol 7: 10 2 | Ethyl acetate 9: 20 3 |
Embodiment 5
Get crude product of lactide 150.0g, carry out recrystallization purifying by table 5, the recrystallization yield is: 35.8%; It is 42.9 ten thousand that polymerization obtains the polylactic acid molecule amount.
Table 5
The recrystallization number of times | For the first time | For the second time | For the third time | The 4th time | The 5th time |
Solvent rac-Lactide and solvent quality proportion crystallization time (h) | Ethanol 7: 10 3 | Ethanol 3: 52 | Ethanol 7: 10 2 | Ethyl acetate 9: 20 3 | Ethyl acetate 3: 44 |
Claims (2)
1. one kind from crude lactide, utilizes the recrystallization method purifying can obtain the method for high percent crystallization in massecuite and high purity rac-Lactide simultaneously, it is characterized in that: obtain high yield with ethyl alcohol recrystallization earlier, obtain high purity with re-crystallizing in ethyl acetate again; Rac-Lactide and alcoholic acid mass ratio are 9: 20~7: 10, and crystallization time is 1h~3h; The mass ratio of rac-Lactide and ethyl acetate is 9: 20~6: 5, and crystallization time is 2h~8h.
2. according to claim 1, it is characterized in that high yield and high purity rac-Lactide obtain by following method:
A is dissolved in rac-Lactide in a kind of organic solvent under 60 ℃~75 ℃, obtains solution, the mass ratio of control rac-Lactide and this organic solvent;
B is at 0 ℃~30 ℃, with solution left standstill, and the period, the rac-Lactide crystallization is separated out, filter and obtain crystal and dry;
C repeats above-mentioned A, B operation, according to the recrystallization number of times, changes the recrystallization solvent kind;
Described a kind of organic solvent is ethanol or ethyl acetate, and for the first time recrystallization solvent is an ethanol, and last recrystallization solvent is an ethyl acetate, utilizes not re-use ethanol after the re-crystallizing in ethyl acetate and carry out recrystallization.
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CN2007101355326A CN101157680B (en) | 2007-11-16 | 2007-11-16 | Method for recrystallizing lactide by using double solvents |
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CN2007101355326A CN101157680B (en) | 2007-11-16 | 2007-11-16 | Method for recrystallizing lactide by using double solvents |
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CN101157680B true CN101157680B (en) | 2010-12-29 |
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Families Citing this family (3)
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CN103151561B (en) * | 2013-03-05 | 2015-07-01 | 华南师范大学 | Electrolytic lithium salt and preparation method and applications of electrolyte solution containing lithium salt |
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 |
CN113292531B (en) * | 2021-05-20 | 2023-09-26 | 重庆大学 | Purification method of mixed lactide of meso-lactide and D, L-lactide |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1757643A (en) * | 2005-10-17 | 2006-04-12 | 南京工业大学 | Method for recrystallizing lactide |
CN1757644A (en) * | 2005-10-17 | 2006-04-12 | 南京工业大学 | Method for recrystallizing lactide by using ethanol |
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CN1757643A (en) * | 2005-10-17 | 2006-04-12 | 南京工业大学 | Method for recrystallizing lactide |
CN1757644A (en) * | 2005-10-17 | 2006-04-12 | 南京工业大学 | Method for recrystallizing lactide by using ethanol |
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