CN108610323A - A kind of preparation method of lactide - Google Patents
A kind of preparation method of lactide Download PDFInfo
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- CN108610323A CN108610323A CN201810612564.9A CN201810612564A CN108610323A CN 108610323 A CN108610323 A CN 108610323A CN 201810612564 A CN201810612564 A CN 201810612564A CN 108610323 A CN108610323 A CN 108610323A
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- lactic acid
- lactide
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- 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
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Abstract
The present invention provides a kind of preparation methods of lactide, including：Lactic acid heats reaction, obtains lactide in the presence of H beta molecular sieves under reduced pressure；The reaction pressure is 50~1500Pa.The present invention is using vacuum, the method for heating, realize the reaction of H beta molecular sieve catalytic lactic acid, it is done directly synthesis of the lactic acid to lactide, the lactide of high-optical-purity (＞ 96%) is obtained, overcomes the method for existing production lactide that need to lead to the disadvantage that technological process is long, reaction temperature is high by oligomeric, Pintsch process.Organic solvent is not used in entire production process, and it is small to only have waste water generation environmental pollution in production；Reaction temperature is low, while being realized by the hydrolysis of lactic acid oligomer and repeating to be catalyzed, and H beta molecular sieves are Ke Xunhuanliyong, simple production process environmental protection, the foreground with potential scale application.
Description
Technical field
The present invention relates to technical field of organic synthesis, more particularly, to a kind of preparation method of lactide.
Background technology
With society and expanding economy, based on petroleum-based nondegradable plastics using more and more extensive；It is produced simultaneously
Raw all kinds of discard is on the rise to the pollution of natural environment；In addition demand of the general-purpose plastics to non-renewable petroleum resources, shadow
Ring the sustainable development to the mankind.The degradation plastic based on biomass is developed, replaces traditional petroleum-based plastics, becomes high score
The research emphasis of sub- Material Field.Polylactic acid is a kind of degradable macromolecule polyester material of biology base, has high mechanics strong
Degree and good processing performance, are suitable for the manufacturing process such as extrusion, injection molding, plastic uptake；It is degradable in the natural environment after discarded to be
Carbon dioxide and water, environmental pollution are small.Currently, polylactic acid (PLA) has become the maximum degradation material of industrialized scale, entirely
The annual output in the world reaches 300,000 tons or more.
The synthesis technology of polylactic acid is divided into two kinds：1. passing through lactic acid one-step method direct polycondensation synthesizing polylactic acid；Patent (CN
Shorten reaction time using molecular sieve dehydrated in situ in 1298764C), while chain extension is carried out using polyalcohol, prepares polylactic acid.
The technique needs condition of high vacuum degree and higher temperature, to equipment requirement height；Commercial application is seldom at present.2. being prepared by lactic acid
Monomers lactide, then lactide ring-opening polymerisation two-step method, prepares polylactic acid or lactide can be with other monomers combined polymerization system
Standby copolymer.The technique is easy to get the polylactic acid or copolymer of high molecular weight, is the main method of current industrialization production.
Lactide becomes the core of technique as polymerized monomer, synthetic method.Oligomeric, cracking prepares lactide using conventional two step sides
Method (CN101492441A) is to carry out oligomeric in vacuum, 180 DEG C or more hot conditions and crack, and reaction process needs high temperature.Patent
In (CN 101747314B), lactic acid monomer and ZnO Depressor responses are used first, oligomerization product are generated, then in ZSM-5 molecules
Sieve need to be in more than 170 degrees Celsius temperatures above cracking production lactides under participating in.In addition, patent (CN101891733B) uses titanium
Base catalyst is catalyzed the direct synthesis of lactide of lactate using ester exchange reaction；But lactate synthesis cost compared with lactic acid
Height is unfavorable for increasing productivity effect.
Invention content
In view of this, the technical problem to be solved in the present invention is to provide a kind of preparation method of lactide, the present invention carries
The preparation method of the lactide of confession is simple, high without solvent, lactide optical purity.
The present invention provides a kind of preparation methods of lactide, including：
Lactic acid heats reaction, obtains lactide in the presence of H-beta molecular sieves under reduced pressure；The reaction pressure is
50~1500Pa.
Preferably, the reaction pressure is 50~300Pa.
Preferably, the reaction temperature is 120~150 DEG C.
Preferably, the reaction time is 4~6h.
Preferably, the silica alumina ratio of the H-beta molecular sieves is 10~200：1.
Preferably, the silica alumina ratio of the H-beta molecular sieves is 10~30：1.
Preferably, the mass ratio 0.5~20 of the lactic acid and H-beta molecular sieves:1.
Preferably, the mass ratio 2~6 of the lactic acid and H-beta molecular sieves:1.
Preferably, the lactic acid includes lactic acid and/or lactic acid polymer, and the optical property of the lactic acid is L-/D- lactic acid
Or L, D mixed lactic.
Preferably, further include that addition water or low concentration lactic acid are hydrolyzed after the reaction, the breast that heating hydrolysis obtains
Acid occurs decompression catalysis and lactide is obtained by the reaction；The mass concentration of the low concentration lactic acid is 40%~60%.
Compared with prior art, the present invention provides a kind of preparation methods of lactide, including：Lactic acid is in H-beta molecules
In the presence of sieve, reaction is heated under reduced pressure, obtains lactide；The reaction pressure is 50~1500Pa.The present invention is using true
Empty, heating method, realizes the reaction of H-beta molecular sieve catalytic lactic acid, is done directly synthesis of the lactic acid to lactide, obtains height
The lactide of optical purity (＞ 96%) overcomes the method for existing production lactide that need to lead to technique by oligomeric, Pintsch process
The high disadvantage of long flow path, reaction temperature.Organic solvent is not used in entire production process, only has waste water in production and generates to environment dirt
It contaminates small；Reaction temperature is low, while being realized by the hydrolysis of lactic acid oligomer and repeating to be catalyzed, and H-beta molecular sieves are Ke Xunhuanliyong,
Simple production process environmental protection, the foreground with potential scale application.
Description of the drawings
Fig. 1 is the GC-MS figures for the lactide that the embodiment of the present invention 2 is prepared；
Lactic acid when Fig. 2 is retention time 4.263 minutes in the GC-MS figures of lactide that the embodiment of the present invention 2 is prepared
Mass spectrogram；
Racemization when Fig. 3 is retention time 6.377 minutes in the GC-MS figures of lactide that the embodiment of the present invention 2 is prepared
The mass spectrogram of lactide；
6.791 minutes L- third of retention time are handed in the GC-MS figures for the lactide that Fig. 4 is prepared for the embodiment of the present invention 2
The mass spectrogram of ester.
Specific implementation mode
The present invention provides a kind of preparation method of lactide, those skilled in the art can use for reference present disclosure, suitably
Modified technique parameter is realized.In particular, it should be pointed out that all similar substitutions and modifications are for a person skilled in the art
It will be apparent that they shall fall within the protection scope of the present invention.The present invention method and application by preferred embodiment into
Description is gone, related personnel can obviously not depart from the content of present invention, carried out to methods herein and application in spirit and scope
It changes or suitably changes and combine, to realize and apply the technology of the present invention.
The present invention provides a kind of preparation methods of lactide, including：
Lactic acid heats reaction, obtains lactide in the presence of H-beta molecular sieves under reduced pressure；The reaction pressure is
50~1500Pa.
According to the present invention, lactic acid heats reaction, obtains lactide in the presence of H-beta molecular sieves under reduced pressure；It is excellent
Choosing is specially that reaction bulb is added in lactic acid and molecular sieve, and oil bath heating stirring is evaporated under reduced pressure, and reaction to no product distillates, and condenses
Guan Zhongwei lactides.
Lactic acid provided by the invention includes lactic acid and/or lactic acid polymer, and the optical property of the lactic acid is L-/D- lactic acid
Or L, D mixed lactic.The present invention to this without limit, it is preferably commercially available.
The present invention for the lactic acid concentration without limit, can be 100%~105%.
There is no particular limitation for H-beta molecular sieves by the present invention, commercially available.It is catalyzed above-mentioned anti-as catalyst
It answers, is not necessarily to two-step reaction, be not necessarily to Pintsch process, while being not necessarily to additional catalysts, reaction environmental protection, simply, reaction temperature
It is low.
The silica alumina ratio of the H-beta molecular sieves is preferably 10~200：1；More preferably 10~50：1；Most preferably
10~30：1.
Wherein, the mass ratio of the lactic acid and H-beta molecular sieves is preferably 0.5~20:1；More preferably 1~10:1；Most
Preferably 2~6:1.
Present invention reaction carries out at reduced pressure；The reaction pressure, i.e. vacuum degree are preferably 50~1500Pa；More
Preferably 50~1000Pa；Most preferably 50~300Pa.
Reaction temperature of the present invention is preferably 120~150 DEG C；More preferably 120~140 DEG C.
The present invention for the oil bath heating and stirring concrete mode without limit, it is well known to those skilled in the art
.
Reaction time of the present invention is preferably 4~6h.
Further include that addition water or low concentration lactic acid are hydrolyzed after the reaction, the lactic acid that heating hydrolysis obtains occurs
Lactide is obtained by the reaction in decompression catalysis；The mass concentration of the low concentration lactic acid is 40%~60%
Specially：After reaction, water is added into reaction bulb or low concentration lactic acid is hydrolyzed, heating hydrolysis obtains
Lactic acid, re-start decompression catalysis obtain lactide, realize the recycled for multiple times of molecular sieve and the recycling of lactic acid oligomer.
The method of the present invention prepares lactide technique there are technological processes long, reaction temperature for oligomeric, cracking conventional at present
High disadvantage is spent, using molecular sieve catalytic lactic acid, realizes the technique that lactic acid directly prepares lactide.This method production without pure
Lactide optical purity processed is high (＞ 96%), and reaction temperature is low (120-160 degrees Celsius), is less than the cracking temperature of existing report,
Reduce energy consumption.The lact-acid oligomer generated in reaction process is recycled using method for hydrolysis, recycling reduces cost.
The method of the present invention prepares lactide using molecular sieve catalytic lactic acid one-step method, has process conditions mild, technique
Simple feature.This method realizes the recycling of molecular sieve, and equipment is simple to operation, is suitable for large-scale production.
The present invention provides a kind of preparation methods of lactide, including：Lactic acid depressurizes item in the presence of H-beta molecular sieves
Reaction is heated under part, obtains lactide；The reaction pressure is 50~1500Pa.The present invention is real using vacuum, the method for heating
Existing H-beta molecular sieve catalytic lactic acid reaction, is done directly synthesis of the lactic acid to lactide, obtains high-optical-purity (＞ 96%)
Lactide, overcoming the method for existing production lactide that need to cause by oligomeric, Pintsch process, technological process is long, reaction temperature is high
The shortcomings that.Organic solvent is not used in entire production process, and it is small to only have waste water generation environmental pollution in production；Reaction temperature is low,
It is realized simultaneously by the hydrolysis of lactic acid oligomer and repeats to be catalyzed, H-beta molecular sieves are Ke Xunhuanliyong, simple production process environmental protection,
Foreground with potential scale application.
In order to further illustrate the present invention, with reference to embodiments to a kind of preparation method of lactide provided by the invention
It is described in detail.
Embodiment 1
2 grams of H-beta molecular sieves (SiO2：Al2O3Molar ratio 25:1), reaction bulb is added in 2 grams of lactic acid (concentration 105%).Instead
It answers bottle to place persistently to stir in 130 DEG C of oil baths of temperature；It is carried out at the same time vacuum distillation, is evaporated without product in reaction bulb after reaction 4 hours
Go out, lactide is obtained in condenser pipe, lactide yield is 27%.
Embodiment 2
1 gram of H-beta molecular sieves (Si：Al molar ratios 12.5:1), reaction bulb is added in 4 grams of lactic acid (concentration 105%).Reaction
Bottle is placed persistently to be stirred in 120 DEG C of oil baths of temperature；It is carried out at the same time vacuum distillation, vacuum degree 300Pa, reaction is reacted after 4 hours
It is distillated without product in bottle, lactide is obtained in condenser pipe, lactide yield is 51%.
The results are shown in Figure 1, and Fig. 1 is the GC-MS figures for the lactide that the embodiment of the present invention 2 is prepared；Fig. 2 is the present invention
In the GC-MS figures for the lactide that embodiment 2 is prepared when retention time 4.263 minutes lactic acid mass spectrogram；Fig. 3 is the present invention
In the GC-MS figures for the lactide that embodiment 2 is prepared when retention time 6.377 minutes meso-lactide mass spectrogram；Fig. 4 is
The mass spectrogram of 6.791 minutes L- lactides of retention time in the GC-MS figures for the lactide that the embodiment of the present invention 2 is prepared.
Embodiment 3
1 gram of H-beta molecular sieves (Si：Al molar ratios 12.5:1), reaction bulb is added in 8 grams of lactic acid (concentration 105%).Reaction
Bottle is placed persistently to be stirred in 130 DEG C of oil baths of temperature；It is carried out at the same time vacuum distillation, vacuum degree 300Pa, reaction is reacted after 6 hours
It is distillated without product in bottle, lactide is obtained in condenser pipe, lactide yield is 43%.
Embodiment 4
1 gram of H-beta molecular sieves (Si：Al molar ratios 12.5:1), reaction bulb is added in 4 grams of lactic acid (concentration 105%).Reaction
Bottle is placed persistently to be stirred in 150 DEG C of oil baths of temperature；It is carried out at the same time vacuum distillation, vacuum degree 350Pa, reaction is reacted after 4 hours
It is distillated without product in bottle, lactide is obtained in condenser pipe, lactide yield is 39%.
Embodiment 5
1 gram of H-beta molecular sieves (Si：Al molar ratios 12.5:1), reaction bulb is added in 4 grams of lactic acid (concentration 90%).Reaction bulb
It places and is persistently stirred in 90 DEG C of oil baths of temperature；Vacuum distillation 1 hour is carried out at 90 DEG C, then oil bath is warming up at 110 DEG C and subtracts
Pressure distillation 1 hour, final oil bath temperature rises to 125 DEG C, distillates without product in reaction bulb after reaction 1 hour, is obtained in condenser pipe
Lactide, lactide yield are 57%.Vacuum degree is 200Pa in reaction process.
The lactide of preparation is measured by GC-MS, optical purity ＞ 96%.Test result is shown in attached drawing 1 and table 1.
Table 1 produces the composition of lactide
Embodiment 6
1 gram of H-beta molecular sieves (Si：Al molar ratios 12.5:1), reaction bulb is added in 4 grams of lactic acid (concentration 90%).Reaction bulb
It places and is persistently stirred in 90 DEG C of oil baths of temperature；Vacuum distillation 1 hour is carried out at 90 DEG C, then oil bath is warming up at 110 DEG C and subtracts
Pressure distillation 1 hour, final oil bath temperature rises to 125 DEG C, distillates without product in reaction bulb after reaction 1 hour, is obtained in condenser pipe
Lactide, lactide yield are 57%.Vacuum degree is 200Pa in reaction process.
It is above-mentioned that 8g (50%) lactic acid is added into reaction bulb after reaction, 90 DEG C of reaction 2h are heated under normal pressure, are then weighed
Multiple following operation：Vacuum distillation 1 hour is being carried out at 90 DEG C successively, oil bath is warming up at 110 DEG C and is evaporated under reduced pressure 1 hour, most
Whole oil bath temperature rises to 125 DEG C, is distillated without product in reaction bulb after reaction 1 hour, and lactide, lactide production are obtained in condenser pipe
Rate is 53%.Vacuum degree is 200Pa in reaction process.
Embodiment 7
1 gram of H-beta molecular sieves (Si：Al molar ratios 32:1), reaction bulb is added in 4 grams of lactic acid (concentration 105%).Reaction bulb
It places and is persistently stirred in 130 DEG C of oil baths of temperature；It is carried out at the same time vacuum distillation, vacuum degree 300Pa, reaction bulb after reaction 6 hours
Middle no product distillates, and lactide is obtained in condenser pipe, and lactide yield is 35%.
Comparative example 1
1 gram of H-beta molecular sieves (Si：Al molar ratios 12.5:1), reaction bulb is added in 4 grams of lactic acid (concentration 105%).Reaction
Bottle is placed persistently to be stirred in 120 DEG C of oil baths of temperature；It is carried out at the same time air-distillation, is distillated without product in reaction bulb after reaction 4 hours,
Lactide is not obtained in condenser pipe, lactide yield is 0.
Comparative example 2
1 gram of ZSM-5 molecular sieve (Si：Al molar ratios 13.5:1), reaction bulb is added in 4 grams of lactic acid (concentration 105%).Reaction bulb
It places and is persistently stirred in 120 DEG C of oil baths of temperature；It is carried out at the same time vacuum distillation, vacuum degree 300Pa, reaction bulb after reaction 4 hours
Middle no product distillates, and lactide is obtained in condenser pipe, and lactide yield is 23%.
Comparative example 3
1 gram of ZSM-5 molecular sieve (Si：Al molar ratios 13.5:1), reaction bulb is added in 4 grams of lactic acid (concentration 105%).Reaction bulb
It places and is persistently stirred in 120 DEG C of oil baths of temperature；It is carried out at the same time air-distillation, is distillated without product in reaction bulb after reaction 4 hours, it is cold
Solidifying Guan Zhongwei obtains lactide, and lactide yield is 0%.
The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications are also answered
It is considered as protection scope of the present invention.
Claims (10)
1. a kind of preparation method of lactide, including：
Lactic acid heats reaction, obtains lactide in the presence of H-beta molecular sieves under reduced pressure；The reaction pressure be 50~
1500Pa。
2. preparation method according to claim 1, which is characterized in that the reaction pressure is 50~300Pa.
3. preparation method according to claim 2, which is characterized in that the reaction temperature is 120~150 DEG C.
4. preparation method according to claim 3, which is characterized in that the reaction time is 4~6h.
5. preparation method according to claim 1, which is characterized in that the silica alumina ratio of the H-beta molecular sieves is 10
~200：1.
6. preparation method according to claim 5, which is characterized in that the silica alumina ratio of the H-beta molecular sieves is 10
~30：1.
7. preparation method according to claim 1, which is characterized in that the mass ratio of the lactic acid and H-beta molecular sieves
0.5~20:1.
8. preparation method according to claim 7, which is characterized in that the mass ratio 2 of the lactic acid and H-beta molecular sieves
~6:1.
9. preparation method according to claim 1, which is characterized in that the lactic acid includes lactic acid and/or lactic acid polymer,
The optical property of the lactic acid is L-/D- lactic acid or L, D mixed lactics.
10. preparation method according to claim 1, which is characterized in that further include that water or low dense is added after the reaction
Degree lactic acid is hydrolyzed, the lactic acid that heating hydrolysis obtains, and decompression catalysis occurs, lactide is obtained by the reaction；The low concentration lactic acid
Mass concentration is 40%~60%.
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112010834A (en) * | 2020-09-23 | 2020-12-01 | 中触媒新材料股份有限公司 | Method for synthesizing glycolide in one step |
| CN112028869A (en) * | 2020-09-23 | 2020-12-04 | 中触媒新材料股份有限公司 | Method for synthesizing lactide in one step |
| CN112574165A (en) * | 2020-12-30 | 2021-03-30 | 安徽丰原生物技术股份有限公司 | Method for generating lactide by one-step conversion |
| CN113234055A (en) * | 2021-05-18 | 2021-08-10 | 扬州大学 | Synthesis method of lactide |
| CN114437017A (en) * | 2020-10-31 | 2022-05-06 | 中国石油化工股份有限公司 | Method for preparing lactide from lactic acid |
| CN114805284A (en) * | 2022-05-11 | 2022-07-29 | 南京大学 | Method for synthesizing lactide by high-concentration lactic acid one-step method |
| CN115141174A (en) * | 2022-07-19 | 2022-10-04 | 珠海市昊岭环保科技有限公司 | Method for one-step synthesis of lactide by catalysis of rare earth molecular sieve catalyst |
| CN115417851A (en) * | 2022-08-30 | 2022-12-02 | 中国科学院长春应用化学研究所 | Method for directly preparing lactide from lactic acid |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112028869A (en) * | 2020-09-23 | 2020-12-04 | 中触媒新材料股份有限公司 | Method for synthesizing lactide in one step |
| CN112010834A (en) * | 2020-09-23 | 2020-12-01 | 中触媒新材料股份有限公司 | Method for synthesizing glycolide in one step |
| CN112010834B (en) * | 2020-09-23 | 2022-04-15 | 中触媒新材料股份有限公司 | Method for synthesizing glycolide in one step |
| CN112028869B (en) * | 2020-09-23 | 2022-04-15 | 中触媒新材料股份有限公司 | Method for synthesizing lactide in one step |
| CN114437017A (en) * | 2020-10-31 | 2022-05-06 | 中国石油化工股份有限公司 | Method for preparing lactide from lactic acid |
| CN112574165A (en) * | 2020-12-30 | 2021-03-30 | 安徽丰原生物技术股份有限公司 | Method for generating lactide by one-step conversion |
| CN112574165B (en) * | 2020-12-30 | 2022-01-07 | 安徽丰原生物技术股份有限公司 | Method for generating lactide by one-step conversion |
| CN113234055A (en) * | 2021-05-18 | 2021-08-10 | 扬州大学 | Synthesis method of lactide |
| CN114805284A (en) * | 2022-05-11 | 2022-07-29 | 南京大学 | Method for synthesizing lactide by high-concentration lactic acid one-step method |
| CN114805284B (en) * | 2022-05-11 | 2023-10-03 | 南京大学 | Method for synthesizing lactide by high-concentration lactic acid one-step method |
| CN115141174A (en) * | 2022-07-19 | 2022-10-04 | 珠海市昊岭环保科技有限公司 | Method for one-step synthesis of lactide by catalysis of rare earth molecular sieve catalyst |
| CN115141174B (en) * | 2022-07-19 | 2023-10-03 | 珠海市昊岭环保科技有限公司 | Method for synthesizing lactide by one step under catalysis of rare earth molecular sieve catalyst |
| CN115417851A (en) * | 2022-08-30 | 2022-12-02 | 中国科学院长春应用化学研究所 | Method for directly preparing lactide from lactic acid |
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Application publication date: 20181002 |
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