CN114773310A - Method for synthesizing optically pure lactide by composite catalysis method - Google Patents
Method for synthesizing optically pure lactide by composite catalysis method Download PDFInfo
- Publication number
- CN114773310A CN114773310A CN202210414266.5A CN202210414266A CN114773310A CN 114773310 A CN114773310 A CN 114773310A CN 202210414266 A CN202210414266 A CN 202210414266A CN 114773310 A CN114773310 A CN 114773310A
- Authority
- CN
- China
- Prior art keywords
- lactide
- lactic acid
- optically pure
- under
- pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- 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
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
- C07B2200/00—Indexing scheme relating to specific properties of organic compounds
- C07B2200/07—Optical isomers
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a method for synthesizing optically pure lactide by a composite catalysis method. The method comprises the following steps: under a first heating condition, adding a composite catalyst consisting of organic guanidine and organic tin into lactic acid, and reacting at normal pressure; carrying out reduced pressure reaction under the first pressure under the second heating condition, and carrying out dehydration condensation polymerization to obtain lactic acid oligomer; under the third heating condition, decompressing, collecting and distilling out crude lactide under the second pressure; and carrying out reduced pressure suction filtration on the crude lactide to obtain filtrate and a filter cake, washing the filter cake, and then carrying out vacuum drying to obtain the optically pure lactide. The method solves the problem that lactide synthesized by singly using stannous octoate is easy to racemize; furthermore, the use of (oligomer) molecular weight control agents to reduce carbonization of lactide at high temperatures facilitates the cracking reaction.
Description
Technical Field
The invention belongs to the technical field of organic materials, relates to a method for synthesizing optically pure lactide by a composite catalysis method, and particularly relates to a method for synthesizing optically pure lactide by adopting an organic guanidine and organic tin composite catalysis method.
Background
Biodegradable plastics are classified into bio-based biodegradable plastics and petrochemical-based biodegradable plastics according to the source of raw materials. At present, petrochemical-based biodegradable plastic PBAT and biological-based biodegradable plastic polylactic acid (PLA) are the higher industrialization degree, and lactide is a key raw material for synthesizing PLA.
Lactide (C)6H8O4) White needle-shaped, melting point 93-95 ℃, boiling point 216 ℃, molecular weight 144, easy to dissolve in chloroform and ethanol, and insoluble in water. The lactide can be divided into L-lactide, D-lactide and meso-lactide.
Publication No. CN110156745A discloses a process for catalytically synthesizing lactide, which adopts a composite catalyst prepared by matching zinc compounds and/or tin compounds with alkali metal compounds. Publication No. CN104710401A discloses a preparation method of lactide, which adopts a composite catalyst of tin oxide/zinc oxide, stannous oxide/zinc oxide/stannous octoate and stannous oxide/stannous octoate. However, the two methods adopt tin composite catalysts to synthesize lactide, have the defect that the obtained product contains more racemized enantiomers, and cause difficulty in obtaining high-light-purity lactide through subsequent separation and purification. Publication No. CN106831700A discloses a method for producing optically pure L/D lactide by a full-green closed cycle process, which adopts a ternary composite catalytic system consisting of bio-organic guanidine SG and biguanide BG as main catalysts and non-toxic metal salt or oxide as a cocatalyst ZC. However, the method adopts a ternary composite catalytic system consisting of bio-organic guanidine SG and biguanide BG as main catalysts and non-toxic metal salt or oxide as an auxiliary catalyst ZC. The method generally needs longer reaction time and higher reaction temperature, and the high temperature is easy to cause the product to generate racemized enantiomer, thereby causing difficulty in obtaining high-light pure lactide through subsequent separation and purification; at the same time, high temperatures also increase the energy consumption.
Based on the research, a plurality of processes for catalytically synthesizing lactide can be developed, but the processes for preparing the lactide have the defect of easy racemization; some defects of high temperature, long time and high energy consumption exist. Therefore, how to find a preparation method of lactide with high yield, low cost and high optical purity is a technical problem to be solved in the field of coating at present.
Disclosure of Invention
Based on the defects in the prior art, the first purpose of the invention is to provide a method for synthesizing optically pure lactide by a composite catalysis method; the second purpose of the invention is to provide the pure L-lactide prepared by the method; the third purpose of the invention is to provide the pure D-lactide prepared by the method.
The scheme is a circulation process for synthesizing optically pure lactide by using a composite catalyst consisting of organic guanidine and organic tin, and can overcome the defects of high racemization possibility or high lactide synthesis temperature, long time and high energy consumption in the prior art of synthesizing lactide by using a single catalyst.
The purpose of the invention is realized by the following technical scheme:
in one aspect, the invention provides a method for synthesizing optically pure lactide by a composite catalysis method, which comprises the following steps:
(1) under a first heating condition, adding a composite catalyst consisting of organic guanidine and organic tin into lactic acid, and reacting at normal pressure;
(2) carrying out reduced pressure reaction under the first pressure under the second heating condition, and carrying out dehydration condensation polymerization to obtain lactic acid oligomer;
(3) under the third heating condition, decompressing, collecting and distilling out crude lactide under the second pressure;
(4) and (3) carrying out reduced pressure suction filtration on the crude lactide collected in the step (3) to obtain filtrate and a filter cake, washing the filter cake, and then carrying out vacuum drying to obtain the optically pure lactide.
In the above method, the lactic acid comprises L-lactic acid or D-lactic acid; when the lactic acid is L-lactic acid, pure L-lactide is prepared; when the lactic acid is D-lactic acid, pure D-lactide is prepared.
In the method, the reaction temperature under the first heating condition is 30-80 ℃, and the reaction time is 1-6 h;
the reaction temperature under the second heating condition is 80-175 ℃, and the reaction time is 2-10 h;
the reaction temperature under the third heating condition is 150-260 ℃, and the reaction time is 0.5-4 h;
the pressure range of the first pressure is 15-60 torr;
the pressure range of the second pressure is 0.5-15 torr.
In the above method, the weight average molecular weight of the lactic acid oligomer is 600 to 2500 Da.
In the above method, in the step (4), the washing of the filter cake specifically comprises: washing the filter cake with 1-10% aqueous alkali, and then washing with deionized water to neutrality;
the temperature for vacuum drying is 20-40 ℃, and the drying time is 24-36 h.
In the method, in the step (1), the mass ratio of the composite catalyst to the lactic acid is 1:100 to 1: 100000;
in the composite catalyst, the mass ratio of the organic guanidine to the organic tin is 100: 1-1: 100.
In the above method, the organic guanidine includes one or more of creatinine, creatine, guanidinoacetic acid, guanine, metformin hydrochloride, moroxydine and phenformin, but is not limited thereto.
In the above method, the organic tin includes one or more of stannous chloride, stannous octoate, stannous sulfate and stannous oxalate, but is not limited thereto.
In the above method, preferably, the composite catalyst composed of organic guanidine and organic tin includes a composite catalyst of one or more of creatinine/stannous chloride, creatinine/stannous octoate, creatine/stannous chloride and creatine/stannous octoate, but is not limited thereto.
In the above method, in the step (1), a molecular weight control agent is further added; the molecular weight control agent is selected from polyols with C3-C10; preferably, the polyol is an alcohol containing three or more hydroxyl groups, including a combination of one or more of glycerol, pentaerythritol, and sorbitol, but not limited thereto.
In the above method, the mass ratio of the molecular weight controlling agent to the lactic acid is 100: 1to 1: 100.
In the method, the filtrate collected in the step (4) is added into the step (1), and the processes of the steps (1) to (4) are repeated to realize a recycling process.
In another aspect, the invention also provides a pure L-lactide prepared by the above method, wherein the L-lactide has a specific brightness [ α ] of: -276 ° to-280 ° (C ═ 1, ethanol, 13 ℃).
In still another aspect, the present invention also provides a pure D-lactide prepared by the above method, wherein the specific brightness [ α ] of the D-lactide is: 280 ° (C ═ 1, ethanol, 13 ℃).
In the prior art, the defect of easy racemization exists in the process of catalytically synthesizing lactide by adopting single organic tin; the lactide synthesized by adopting a single organic guanidine catalyst has the defects of high temperature, long time and high energy consumption.
The invention has the beneficial effects that:
(1) the method solves the problem that lactide synthesized by catalysis of organotin is easy to racemize. The single use of organic tin for catalytic synthesis of lactide has a cracking temperature of 180-200 ℃, a vacuum degree of 1Torr, a cracking time of less than 2h and a meso configuration of 10-30%; and the use amount of organic tin is reduced, and the proportion of meso configuration is reduced to between 1 and 10 percent when the organic tin and the organic guanidine are compounded for use. The effective rate and the high selectivity of the reaction tendency overcome and improve three technical barriers on the development of the lactide in China: low yield, high cost and low optical purity.
(2) The use of (oligomeric) molecular weight control agents to reduce carbonization of lactide at high temperatures facilitates the cracking reaction. The (oligomer) molecular weight control agent (such as sorbitol) is used as a high-boiling-point solvent in the invention, which is beneficial to the lactide to be distilled out smoothly at high temperature and reduces the risk of the lactide to be carbonized at high temperature. In addition, the (oligomer) molecular weight control agent (such as sorbitol) contains a plurality of hydroxyl groups, and in the formation process of the lactic acid oligomer, the addition of sorbitol is favorable for controlling the rapid increase of the molecular weight of the lactic acid oligomer, and is maintained between 1000-2000Da, thereby being favorable for the progress of the cracking reaction.
Description of the drawings:
in order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed for the present invention in the embodiments or the prior art descriptions will be briefly introduced below, and it is obvious that the drawings related to the present invention in the following descriptions are only some embodiments of the present invention, and other drawings can be obtained according to the drawings without creative efforts for those skilled in the art.
FIG. 1 is a high performance liquid chromatogram of example 1;
FIG. 2 is a high performance liquid chromatogram of comparative example 2.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below. However, it will be appreciated by those of ordinary skill in the art that numerous technical details are set forth in order to provide a better understanding of the present invention in its various embodiments. However, the technical solutions claimed in the claims of the present invention can be implemented without these technical details and with various changes and modifications based on the following embodiments. The raw materials used in the following examples of the present invention were all conventionally commercially available unless otherwise specified, and the experimental procedures used were all those conventionally conducted in the art unless otherwise specified.
Example 1:
this example provides a method for preparing pure L-lactide, which comprises the following steps:
adding 800g of L-lactic acid (the chemical content is 98.5%, the water content is 1.5%), 20g of D-sorbitol, 0.08g of creatinine (0.01% by weight compared with the L-lactic acid) and 0.08g of stannous octoate (0.01% by weight compared with the L-lactic acid) into a 1000mL three-neck flask, and heating and dehydrating at 60-80 ℃ for 2 hours under the condition of 16 torr; dehydrating for 10 hours at 80-175 ℃.
Monitoring the molecular weight of the lactic acid oligomer to be between 1000 and 2000Da, then increasing the vacuum degree of the system to 1.2torr, raising the temperature to 200 ℃ for cracking, and cracking for 3h to obtain 660g of crude L-lactide. The crude product was filtered under reduced pressure to give 160g of filtrate.
Approximately 500g of the resulting white solid as a filter cake was placed in a 1000mL beaker and 300g of 5% Na was added2CO3Stirring the aqueous solution for 10min, and performing suction filtration; the filter cake obtained is washed with 300mL of deionized water x 2 times and dried in vacuum at 40 ℃ to obtain 425g of white pure L-lactide product.
Through detection, the yield is as follows: 66.4%, [ α ]: 277.3 ° (C ═ 1, ethanol, 13 ℃), melting range: 95.6-98.3 ℃, free acid: 0.045% (450ppm), L-lactide gas phase content: 99.14 percent.
Recovery example 1: (1000mL recovery of reaction filtrate and mother liquor)
A1000 mL three-necked flask of example 1 was charged with 36g of the mother liquor, 160g of the obtained filtrate was charged into the system, and 604g of L-lactic acid (chemical content: 98.5%, water content: 1.5%) was added thereto. Heating and dehydrating for 2h at the temperature of 60-80 ℃ and the pressure of 20 torr; heating and dehydrating at 80-175 ℃ under 20torr for 10 h.
Monitoring the molecular weight of the lactic acid oligomer to be between 1000 and 2000Da, then increasing the vacuum degree of the system to 1.0torr, raising the temperature to 200 ℃ for cracking for 3h, and obtaining 675g crude L-lactide. The crude product was suction filtered under reduced pressure to give 170g of filtrate.
About 520g of the resulting white solid as a filter cake was placed in a 1000mL beaker and 300g of 5% Na was added2CO3Stirring the aqueous solution for 10min, and performing suction filtration; the obtained filter cake is washed by deionized water 300mL multiplied by 2 times and dried in vacuum at 40 ℃ to obtain 450g of white pure L-lactide product.
Through detection, the yield is as follows: 70.3%, [ α ]: 276.5 ° (C1, ethanol, 13 ℃), melting range: 94.7-97.4 ℃, free acid: 0.055% (550ppm), L-lactide gas phase content: 98.6 percent.
Example 2:
this example provides a method for preparing pure L-lactide, which comprises the following steps:
adding 4000g of L-lactic acid (the chemical content is 98.5 percent, the water content is 1.5 percent), 100g of D-sorbitol, 0.4g of creatinine (0.01 percent by weight is compared with the L-lactic acid) and 0.4g of stannous octoate (0.01 percent by weight is compared with the L-lactic acid) into a 5000mL three-neck flask, and heating and dehydrating at the temperature of 60-80 ℃ for 3 hours at the pressure of 25 torr; dehydrating for 10 hours at the temperature of 80-175 ℃.
Monitoring the molecular weight of the lactic acid oligomer to be between 1000 and 2000Da, then increasing the vacuum degree of the system to 2.0torr, raising the temperature to 200 ℃ for cracking for 5 hours, and obtaining 3300g of crude L-lactide. The crude product was suction-filtered under reduced pressure to give 820g of filtrate.
About 2480g of the resulting white solid as a filter cake was placed in a 5000mL beaker and 1600g of 5% Na was added2CO3Stirring the aqueous solution for 10min, and performing suction filtration; the obtained filter cake is washed by deionized water 1200mL multiplied by 2 times and dried in vacuum at 40 ℃ to obtain 2400g of white pure L-lactide product.
Through detection, the yield is as follows: 75.0%, [ α ]: 280.3 ° (C1, ethanol, 13 ℃), melting range: 96.2-98.5 ℃, free acid: 0.056% (560ppm), L-lactide gas phase content: 99.23 percent.
Recovery example 2: (5000mL recovery of reaction filtrate and mother liquor)
In a 5000mL three-necked flask of example 3, in which the mother liquor contained 120g, 820g of the obtained filtrate was charged and 3060g of L-lactic acid (chemical content: 98.5%, water content: 1.5%) was added. Heating and dehydrating for 5 hours at the temperature of 60-80 ℃ and under the pressure of 25 torr; dehydrating for 10 hours at the temperature of 80-175 ℃.
Monitoring the molecular weight of the lactic acid oligomer to be between 1000 and 2000Da, then increasing the vacuum degree of the system to 2.5torr, raising the temperature to 200 ℃ for cracking for 5h, and obtaining 3520g of crude L-lactide. The crude product was suction-filtered under reduced pressure to give 830g of filtrate.
About 2690g of the resulting white solid as a filter cake was placed in a 5000mL beaker and 1600g of 5% Na was added2CO3Stirring the aqueous solution for 10min, and performing suction filtration; the resulting filter cake was washed with 1200mL × 2 times of deionized water and dried under vacuum at 40 ℃ to give 2608g of a white pure L-lactide product.
Through detection, the yield is as follows: 81.5%, [ α ]: 280.6 ° (C1, ethanol, 13 ℃), melting range: 96.3-98.2 ℃, free acid: 0.036% (360ppm), L-lactide gas phase content: 99.21 percent.
Example 3:
this example provides a method for preparing pure D-lactide, which comprises the following steps:
adding 800g of L-lactic acid (with the chemical content of 98.5 percent and the water content of 1.5 percent), 20g of D-sorbitol, 0.08g of creatinine (with the weight of 0.01 percent compared with that of the D-lactic acid) and 0.08g of stannous octoate (with the weight of 0.01 percent compared with that of the D-lactic acid) into a 1000mL three-neck flask, and heating and dehydrating at the temperature of 60-80 ℃ for 2 hours at 15 torr; dehydrating for 10 hours at the temperature of 80-175 ℃.
Monitoring the molecular weight of the lactic acid oligomer to be between 1000 and 2000Da, then increasing the vacuum degree of the system to 1.0torr, raising the temperature to 200 ℃ for cracking, and cracking for 3h to obtain 640g of crude D-lactide. The crude product was suction filtered under reduced pressure to give 135g of filtrate.
Approximately 505g of the resulting white solid from the filter cake was placed in a 1000mL beaker and 300g of 5% Na was added2CO3Stirring the aqueous solution for 10min, and performing suction filtration; the obtained filter cake is washed with deionized water 300mL multiplied by 2 times and dried in vacuum at 40 ℃ to obtain 420g of white pure D-lactide product.
Through detection, the yield is as follows: 65.6%, [ α ]: 278.7 ° (C ═ 1, ethanol, 13 ℃), melting range: 95.3-97.9 ℃, free acid: 0.052% (520ppm), D-lactide gas phase content: 99.06 percent.
Recovery example 3: (1000mL recovery and use of reaction filtrate and mother liquor)
In a 1000mL three-necked flask of example 5, in which 40g of the mother liquor was contained, 135g of the obtained filtrate was charged into the system, and 625g of D-lactic acid (chemical content: 98.5%, water content: 1.5%) was additionally added. Heating and dehydrating for 2 hours at the temperature of 60-80 ℃ and under the pressure of 25 torr; dehydrating for 10 hours at the temperature of 80-175 ℃.
Monitoring the molecular weight of the lactic acid oligomer to be between 1000 and 2000Da, then increasing the vacuum degree of the system to 1.5torr, raising the temperature to 200 ℃ for cracking, and cracking for 3h to obtain 665g of crude D-lactide. The crude product was suction filtered under reduced pressure to give 163g of filtrate.
Approximately 502g of the resulting white solid as a filter cake was placed in a 1000mL beaker and 300g of 5% Na was added2CO3Stirring the aqueous solution for 10min, and performing suction filtration; the filter cake obtained was washed with 300mL × 2 times of deionized water and dried under vacuum at 40 ℃ to obtain 458g of white pure D-lactide product.
Through detection, the yield is as follows: 71.6%, [ α ]: 280.2 ° (C1, ethanol, 13 ℃), melting range: 95.7-97.2 ℃, free acid: 0.043% (430ppm), D-lactide gas phase content: 98.96 percent.
Example 4:
this example provides a method for preparing L-lactide, which comprises the following steps:
adding 800g of L-lactic acid (with the chemical content of 98.5 percent and the water content of 1.5 percent), 1.6g of creatinine (with the weight of 0.2 percent compared with that of the L-lactic acid), 1.6g of stannous octoate (with the weight of 0.2 percent compared with that of the L-lactic acid) and 200g of glycerol into a 1000mL three-neck flask, and heating and dehydrating for 2 hours at the temperature of 60-80 ℃ at the pressure of 16 torr; heating at 80-175 ℃ for esterification and dehydration for 6 h. The molecular weight of the lactic acid oligomer was monitored at around 1600 Da. Then the vacuum degree of the system is increased to 1.0torr, the temperature is increased to 210 ℃ for cracking, the cracking time is 3h, about 640g of crude L-lactide is obtained, and the yield is about 80%.
Comparative example 1:
the present comparative example provides a method of preparing L-lactide, the method comprising:
adding 800g of L-lactic acid (chemical content 98.5%, water content 1.5%) and 0.16g of creatinine (0.2% wt is compared with L-lactic acid) into a 1000mL three-neck flask, and heating and dehydrating at 60-80 ℃ for 2h under 16 torr; heating at 80-175 ℃ for esterification and dehydration for 6 h. The molecular weight of the lactic acid oligomer was monitored between 1000 and 2000 Da. And then, the vacuum degree of the system is increased to 1.2torr, the temperature is increased to 220 ℃ for cracking, the cracking time is 2 hours, about 70g of crude L-lactide is obtained, and the effective yield is 10.9%. The color of the system is dark red, meanwhile, the viscosity is large at 220 ℃, the product can not be steamed out after the prolonged time, then the temperature is continuously increased to 250 ℃ under the condition that the vacuum degree is 1.0torr, the cracking is continuously carried out for 3 hours, the viscosity of the reaction system is large, more product can not be steamed out, and the cracking can not be smoothly carried out. The remaining mother liquor was cooled to a lumpy solid mass with an average molecular weight above 5000Da, which is presumed to be more prone to polymerization under creatinine catalysis alone.
The single use of creatinine can not effectively evaporate lactide, the cracking temperature is 220-250 ℃, the vacuum degree is 1Torr, the cracking time is more than 5 hours, and the evaporation efficiency is only 10-20%. And the viscosity of the reaction system is gradually increased along with the increase of time, so that the reaction system is more prone to polymerization reaction rather than cracking reaction.
Comparative example 2: (lactide catalyzed by stannous octoate alone)
The present comparative example provides a method for producing L-lactide, which comprises:
adding 800g of L-lactic acid (with the chemical content of 98.5 percent and the water content of 1.5 percent) and 4g of stannous octoate (with the weight of 0.5 percent being compared with that of the L-lactic acid) into a 1000mL three-neck flask, and heating and dehydrating for 2 hours at the temperature of 60-80 ℃ at the pressure of 16 torr; heating, esterifying and dehydrating for 4 hours at the temperature of 80-175 ℃. The molecular weight of the lactic acid oligomer was monitored around 1300 Da. Then the vacuum degree of the system is increased to 1.0torr, the temperature is increased to 200 ℃ for cracking, the cracking time is 1h, about 560g of crude L-lactide is obtained, and the yield is about 73%.
FIG. 1 is a high performance liquid chromatogram of example 1, as can be seen from FIG. 1: the composite catalyst of creatinine and stannous octoate is used for synthesizing optical pure lactide, the cracking temperature is 180-200 ℃, the vacuum degree is 1Torr, the cracking time is equivalent to that of singly using stannous octoate, and the cracking time is shorter than that of singly using creatinine; the meso-configuration peaks at about 32min, accounting for 4.55%; the L-configuration peaked at about 34.6min, which accounted for 93.84%.
FIG. 2 is a high performance liquid chromatogram of comparative example 2, from which FIG. 2 can be seen: the meso-configuration (meso) of lactide synthesized by singly using stannous octoate catalysis shows a peak at about 32min, accounting for 10.59%; the L-configuration peaked at about 34.6min, accounting for 84.55%.
Finally, it will be understood by those skilled in the art that the foregoing embodiments are specific examples of the invention, and that various changes in form and detail may be made therein without departing from the spirit and scope of the invention in practice.
Claims (10)
1. A method for synthesizing optically pure lactide by a composite catalysis method comprises the following steps:
(1) under a first heating condition, adding a composite catalyst consisting of organic guanidine and organic tin into lactic acid, and reacting at normal pressure;
(2) carrying out reduced pressure reaction under the first pressure under the second heating condition, and carrying out dehydration condensation polymerization to obtain a lactic acid oligomer;
(3) under the third heating condition, decompressing, collecting and distilling out crude lactide under the second pressure;
(4) and (4) carrying out reduced pressure suction filtration on the crude lactide collected in the step (3) to obtain filtrate and filter cake, washing the filter cake, and then carrying out vacuum drying to obtain the optically pure lactide.
2. The method for the hybrid catalytic synthesis of optically pure lactide according to claim 1, wherein: the lactic acid comprises L-lactic acid or D-lactic acid; when the lactic acid is L-lactic acid, pure L-lactide is prepared; when the lactic acid is D-lactic acid, pure D-lactide is prepared.
3. The method for the hybrid catalytic synthesis of optically pure lactide according to claim 1, wherein: the reaction temperature under the first heating condition is 30-80 ℃, and the reaction time is 1-6 h;
the reaction temperature under the second heating condition is 80-175 ℃, and the reaction time is 2-10 h;
the reaction temperature under the third heating condition is 150-260 ℃, and the reaction time is 0.5-4 h;
the pressure range of the first pressure is 15-60 torr;
the pressure range of the second pressure is 0.5-15 torr.
4. The method for the complex catalytic synthesis of optically pure lactide according to claim 1, wherein: the weight average molecular weight of the lactic acid oligomer is 600-2500 Da.
5. The method for the hybrid catalytic synthesis of optically pure lactide according to claim 1, wherein: in the step (4), the washing of the filter cake is specifically as follows: washing the filter cake with 1-10% aqueous alkali, and then washing with deionized water to neutrality;
the temperature for vacuum drying is 20-40 ℃, and the drying time is 24-36 h.
6. The method for the complex catalytic synthesis of optically pure lactide according to claim 1, wherein: in the step (1), the mass ratio of the composite catalyst to the lactic acid is 1: 100-1: 100000;
in the composite catalyst, the mass ratio of the organic guanidine to the organic tin is 100: 1-1: 100.
7. The method for the hybrid catalytic synthesis of optically pure lactide according to claim 1, wherein: in the step (1), a molecular weight control agent is further added; the molecular weight control agent is selected from polyols with C3-C10;
the mass ratio of the molecular weight control agent to the lactic acid is 100: 1-1: 100.
8. The method for the complex catalytic synthesis of optically pure lactide according to claim 1, wherein: the method also comprises the step of adding the filtrate collected in the step (4) into the step (1), and repeating the flows of the steps (1) to (4) to realize a recycling process.
9. The pure L-lactide prepared by the method for compositely and catalytically synthesizing the optically pure lactide according to any one of claims 1to 8, wherein the specific brightness [ alpha ] of the L-lactide is as follows: -276 ° to-280 ° (C ═ 1, ethanol, 13 ℃).
10. The pure D-lactide prepared by the method for compositely and catalytically synthesizing the optically pure lactide according to any one of claims 1to 8, wherein the specific brightness [ alpha ] of the D-lactide is as follows: 280 ° (C ═ 1, ethanol, 13 ℃).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210414266.5A CN114773310A (en) | 2022-04-20 | 2022-04-20 | Method for synthesizing optically pure lactide by composite catalysis method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210414266.5A CN114773310A (en) | 2022-04-20 | 2022-04-20 | Method for synthesizing optically pure lactide by composite catalysis method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114773310A true CN114773310A (en) | 2022-07-22 |
Family
ID=82431767
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210414266.5A Pending CN114773310A (en) | 2022-04-20 | 2022-04-20 | Method for synthesizing optically pure lactide by composite catalysis method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114773310A (en) |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102766132A (en) * | 2012-08-14 | 2012-11-07 | 北京普利玛科技有限责任公司 | Method for preparing lactide continuously |
| CN102775380A (en) * | 2012-08-14 | 2012-11-14 | 南京工业大学 | Process for preparing lactide through fixed acid method |
| CN103193759A (en) * | 2013-04-24 | 2013-07-10 | 南京大学 | Technological method for synthesizing optical pure L-/D-lactide by using biomass organic guanidine catalyst method |
| CN105801555A (en) * | 2016-03-31 | 2016-07-27 | 东华大学 | Perparation method of polymer-grade lactide |
| CN106397389A (en) * | 2016-09-07 | 2017-02-15 | 南京大学 | Process method for fully-green synthesis of glycolide |
| CN106831700A (en) * | 2017-03-28 | 2017-06-13 | 南京大学 | A kind of method of full green sealing circulation technology production optical voidness L/D lactides |
| CN110128397A (en) * | 2019-06-12 | 2019-08-16 | 山东谷雨春生物科技有限公司 | A kind of preparation method of high-purity lactide |
| CN112250661A (en) * | 2020-11-18 | 2021-01-22 | 南京大学 | Method for catalytically synthesizing lactide |
| CN113582965A (en) * | 2021-08-23 | 2021-11-02 | 扬州惠通科技股份有限公司 | Method for preparing high-purity lactide based on catalytic cracking of organic guanidine complex |
| CN113651794A (en) * | 2021-09-15 | 2021-11-16 | 珠海格力新材料有限公司 | Lactide synthesis method |
| CN113956230A (en) * | 2021-10-09 | 2022-01-21 | 江苏睿安应用生物技术股份有限公司 | Synthesis method of high-purity lactide |
| CN114105936A (en) * | 2021-11-10 | 2022-03-01 | 中粮营养健康研究院有限公司 | Method for preparing lactide from lactic acid |
-
2022
- 2022-04-20 CN CN202210414266.5A patent/CN114773310A/en active Pending
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102766132A (en) * | 2012-08-14 | 2012-11-07 | 北京普利玛科技有限责任公司 | Method for preparing lactide continuously |
| CN102775380A (en) * | 2012-08-14 | 2012-11-14 | 南京工业大学 | Process for preparing lactide through fixed acid method |
| CN103193759A (en) * | 2013-04-24 | 2013-07-10 | 南京大学 | Technological method for synthesizing optical pure L-/D-lactide by using biomass organic guanidine catalyst method |
| CN105801555A (en) * | 2016-03-31 | 2016-07-27 | 东华大学 | Perparation method of polymer-grade lactide |
| CN106397389A (en) * | 2016-09-07 | 2017-02-15 | 南京大学 | Process method for fully-green synthesis of glycolide |
| CN106831700A (en) * | 2017-03-28 | 2017-06-13 | 南京大学 | A kind of method of full green sealing circulation technology production optical voidness L/D lactides |
| CN110128397A (en) * | 2019-06-12 | 2019-08-16 | 山东谷雨春生物科技有限公司 | A kind of preparation method of high-purity lactide |
| CN112250661A (en) * | 2020-11-18 | 2021-01-22 | 南京大学 | Method for catalytically synthesizing lactide |
| CN113582965A (en) * | 2021-08-23 | 2021-11-02 | 扬州惠通科技股份有限公司 | Method for preparing high-purity lactide based on catalytic cracking of organic guanidine complex |
| CN113651794A (en) * | 2021-09-15 | 2021-11-16 | 珠海格力新材料有限公司 | Lactide synthesis method |
| CN113956230A (en) * | 2021-10-09 | 2022-01-21 | 江苏睿安应用生物技术股份有限公司 | Synthesis method of high-purity lactide |
| CN114105936A (en) * | 2021-11-10 | 2022-03-01 | 中粮营养健康研究院有限公司 | Method for preparing lactide from lactic acid |
Non-Patent Citations (1)
| Title |
|---|
| 成娜: "生物质肌酐催化法合成光学纯丙交酯的研究", 中国优秀硕士学位论文全文数据库工程科技I辑, pages 1 - 60 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9284290B2 (en) | Process for the production of the mixture 2,4 furandicarboxylic acid (FDCA) and 2,5 furandicarboxylic acid via disproportionation reaction | |
| CN102746500B (en) | Method for synthesizing high-molecular-weight poly(lactic acid) through melt polycondensation of lactic acid under catalysis of three-way composite catalyst | |
| CN113582965A (en) | Method for preparing high-purity lactide based on catalytic cracking of organic guanidine complex | |
| CN112142968B (en) | Process for preparing polylactic acid through lactide ring-opening polymerization | |
| JP7453478B2 (en) | Method for preparing recycled polyester by closed loop recovery of waste polyester with typical green and low carbon properties | |
| KR101459819B1 (en) | A method for lactide synthesis from lactic acid salt | |
| KR20220037999A (en) | A Catalyst for Catalytic Depolymerization of Polymer containing Ester Group and the Depolymerization Method Using the Same | |
| CN114773310A (en) | Method for synthesizing optically pure lactide by composite catalysis method | |
| CN101270184B (en) | PET polyester grain synthesized with inorganic titanium-magnesium catalyst and uses thereof | |
| KR101886434B1 (en) | A Method for Lactide Synthesis from Lactic acid | |
| CN101434539B (en) | Preparation of benzyl acetate | |
| CN113087885B (en) | Production method of recycled polyester chips | |
| CN110951063B (en) | Catalyst composition for preparing polyester and preparation method of polyester | |
| CN112742418B (en) | Catalyst for catalyzing meso-lactide to prepare D, L-lactide and preparation method thereof | |
| CN110105324A (en) | The method that zinc Isoocatanoate catalyzes and synthesizes lactide | |
| CN115772258B (en) | Preparation method of intrinsic type degradable bioactive polyester | |
| CN109180475B (en) | Method for synthesizing diisooctyl terephthalate through rapid esterification without alkali washing and water washing | |
| CN110467525B (en) | Method for preparing lactic acid by selective catalytic conversion of biomass polyol | |
| CN113788937B (en) | Synthesis method of lactide catalyzed by crystalline porous polymer material in limited area | |
| KR102648916B1 (en) | Preparation method of terephthalic acid and terephthalic acid prepared therefrom | |
| KR101428340B1 (en) | A method for preparing lactide using a ionic solvent | |
| CN114478469B (en) | Preparation method of low-water-content crude glycolide and glycolide obtained by preparation method | |
| CN112675916A (en) | Application of metal organic framework material as catalyst in preparation of plasticizer | |
| JP2023146176A (en) | Method of producing polyester resin | |
| CN117185920A (en) | Method for degrading polyester, degradation product obtained by same and application of degradation product |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |