CN115141174B - Method for synthesizing lactide by one step under catalysis of rare earth molecular sieve catalyst - Google Patents
Method for synthesizing lactide by one step under catalysis of rare earth molecular sieve catalyst Download PDFInfo
- Publication number
- CN115141174B CN115141174B CN202210846793.3A CN202210846793A CN115141174B CN 115141174 B CN115141174 B CN 115141174B CN 202210846793 A CN202210846793 A CN 202210846793A CN 115141174 B CN115141174 B CN 115141174B
- Authority
- CN
- China
- Prior art keywords
- lactide
- molecular sieve
- rare earth
- lactic acid
- sieve catalyst
- 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.)
- Active
Links
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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J29/00—Catalysts comprising molecular sieves
- B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
- B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
- B01J29/405—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively containing rare earth elements, titanium, zirconium, hafnium, zinc, cadmium, mercury, gallium, indium, thallium, tin or lead
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
- B01J2229/10—After treatment, characterised by the effect to be obtained
- B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
- B01J2229/186—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself not in framework positions
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Catalysts (AREA)
Abstract
The invention discloses a method for synthesizing lactide by one step catalyzed by a rare earth molecular sieve catalyst. The method comprises the step of adding yttrium oxide (Y 2 O 3 ) The catalyst is loaded on ZSM-5 zeolite molecular sieve to prepare rare earth molecular sieve catalyst, and under the catalysis of the catalyst, L-lactic acid is used as raw material, xylene is used as solvent, and lactide can be synthesized in one step. The method obviously shortens the reaction time for producing lactide, has mild reaction conditions, simple operation, low requirement on vacuum degree, can generate lactide even under normal pressure, and can directly return to the next batch of reaction for continuous use without any treatment. The method provided by the invention reduces the generation of racemized lactide, has high yield and purity of lactide, and reduces the production cost of lactide.
Description
Technical Field
The invention relates to the field of chemical industry, in particular to a method for synthesizing lactide (L-lactide) by one step under the catalysis of a rare earth molecular sieve catalyst.
Background
The rapid industrialization of the world has led to global economies, for the 20 th century, to a great extent dependent on fossil fuel resources, in particular petroleum resources. Notably, with the rapid development of industry and the growth of global population, the consumption of petroleum resources has increased greatly. Petroleum, however, is not a recoverable resource and its reserves are limited. In addition, carbon dioxide emissions from fossil fuel consumption are responsible for global warming. Improving the economic efficiency of petroleum and reducing the emission of carbon dioxide is always the focus of research in related industries.
Polylactic acid (PLA), also known as polylactide, is a linear aliphatic polyester, and is also a carbon neutral and environmentally friendly thermoplastic polymer. Polylactic acid is polymerized from lactic acid obtained by fermenting starch or cellulose. Polylactic acid is a biodegradable plastic, and polylactic acid compost can be decomposed into carbon dioxide and water in 3 months. The existing production method of polylactic acid comprises the following steps: the first step is to synthesize lactide from lactic acid, and the second step is to generate polylactic acid by lactide ring-opening polymerization, wherein the lactide is a key intermediate for producing the polylactic acid. At present, most of the processes for producing lactide in enterprises adopt lactic acid oligomer prepared by high-temperature polycondensation and then lactide is obtained by high-temperature cracking and purification of the oligomer. The preparation process has the advantages of long period, high energy consumption, high process condition requirement, low product yield and serious racemization, so that the manufacturing cost of lactide and polylactic acid is high.
At present, developing a catalyst with high activity and strong selectivity is also an effective method for simplifying the lactide synthesis method, for example, CN113582965A discloses a method for preparing high-purity lactide based on catalytic cracking of an organic guanidine complex, and the method uses the organic guanidine and nontoxic metal salt as raw materials to react to obtain the organic guanidine complex; condensing lactic acid and ZnO under heating and pressurizing conditions to prepare a lactic acid oligomer; and then carrying out depolymerization reaction by taking the organic guanidine complex as a depolymerization catalyst to obtain crude lactide. CN109894109A discloses a catalyst for preparing lactide from lactic acid and a method for preparing lactide from lactic acid, wherein the catalyst is prepared from butyl titanate and zinc nitrate serving as raw materials by a sol-gel method to obtain ZnO-TiO 2 And (3) carrying out hydrothermal sealing treatment on the composite oxide loaded on the graphene oxide to obtain the catalyst. After lactic acid is dehydrated, the catalyst is used for catalyzing, polycondensing is carried out at the temperature of between 5.0 and 15.0kPa and between 140 and 150 ℃, depolymerizing is carried out at the temperature of between 500 and 1000Pa and between 160 and 200 ℃, and crude lactide is obtained after purification. The above method, although using a catalyst, still requires a lactic acid polycondensation reaction and an oligomer depolymerization reaction, which is not only cumbersome in steps but also requires high temperature and high pressure, and is not suitable for industrial production.
Disclosure of Invention
The invention provides a method for synthesizing lactide by one step under the catalysis of a rare earth molecular sieve catalyst. The method comprises the step of adding yttrium oxide (Y 2 O 3 ) The catalyst is loaded on ZSM-5 zeolite molecular sieve to prepare rare earth molecular sieve catalyst, and can synthesize lactide in one step under the catalysis of the catalyst, so that the preparation period of lactide can be shortened, the energy consumption can be reduced, and the yield and chiral purity of lactide can be improved.
The technical scheme of the invention is as follows: a method for synthesizing lactide by one step catalyzed by rare earth molecular sieve catalyst is characterized in that,
(1) Preparation of rare earth molecular sieve catalyst
Adding yttrium oxide into distilled water, adding zeolite ZSM-5 molecular sieve, stirring to obtain suspension, adding NaOH solution into the suspension, regulating pH to 8.5-9.5, stirring at room temperature for 1-1.5 h, stirring at 80-90 ℃ for 1-3 h, centrifuging, repeatedly washing the obtained solid with deionized water until no sodium ion exists, drying the obtained solid, grinding and sieving with a 100-mesh sieve to obtain the rare earth molecular sieve catalyst;
(2) Preparation of lactide
Adding L-lactic acid, the rare earth molecular sieve catalyst obtained in the step (1) and dimethylbenzene into a reaction container, uniformly stirring, and heating to 120-160 ℃ to react for 5-10h to obtain a mixture containing lactide, lactic acid oligomer and dimethylbenzene;
(3) Post-treatment
And (3) carrying out vacuum distillation on the mixture containing lactide, lactic acid oligomer and solvent xylene in the step (2), recovering the solvent xylene, extracting residues to obtain a crude product of lactide, recrystallizing the crude product, and drying to obtain a refined product of lactide.
Further, the mass ratio of the yttrium oxide to the zeolite ZSM-5 molecular sieve in the step (1) is 10-20: 100, preferably 15:100.
further, the drying in the step (1) is as follows: drying at 100-120 deg.c for 10-15 hr.
Further, the L-lactic acid in the step (2) is anhydrous L-lactic acid with the content of more than 99%, and free water can be removed by heating (110 ℃) under normal pressure from the L-lactic acid with the content of 80-90%.
Further, the mass ratio of the L-lactic acid to the rare earth molecular sieve catalyst in the step (2) is 1: (0.01-0.03).
Further, the volume ratio of the L-lactic acid to the dimethylbenzene in the step (2) is 1: (0.4-1.0).
Further, the reaction of the step (2) is carried out under normal pressure; or the reaction is carried out under the condition of negative pressure (vacuum degree-40-50 Kpa).
Further, the extraction in the step (3) is as follows: extracting with water and ethyl acetate in equal volume, removing water layer, and distilling ethyl acetate to obtain crude lactide product.
Further, the recrystallization in the step (3) is as follows: recrystallizing with absolute ethanol.
Further, the distillation temperature of the vacuum distillation in the step (3) is 145 ℃, and the vacuum degree is-95 Kpa. The solvent xylene recovered by vacuum distillation can be returned to the next batch for further use.
The technical principle of the invention is as follows: yttria has excellent chemical durability, thermal stability, fire resistance, corrosion resistance and photochemical stability, and has catalytic activity of redox switch. The presence of sp in L-lactic acid 2 C chiral atoms, lactic acid monomers form a transition state near the active yttrium metal center, and then yttrium metal breaks away to polymerize lactic acid into L-lactide. Yttrium oxide (Y) 2 O 3 ) The ZSM-5 zeolite molecular sieve is loaded on a ZSM-5 zeolite molecular sieve, the ZSM-5 zeolite molecular sieve contains ten membered rings, the basic structural unit is composed of eight five membered rings, the crystal structure of the ZSM-5 zeolite molecular sieve belongs to an orthorhombic crystal system, the ZSM-5 zeolite molecular sieve has a large specific surface area, the catalytic activity and selectivity of yttrium oxide can be improved, and side reactions are reduced.
The beneficial effects of the invention are as follows: the method provided by the invention obviously shortens the reaction time for producing lactide, has mild reaction conditions, simple operation, low requirement on vacuum degree, and can generate lactide even under normal pressure, and the solvent can be directly returned to the next batch for continuous use without any treatment. The method provided by the invention reduces the generation of racemized lactide, has high yield and purity of lactide, and reduces the production cost of lactide. Reduces the consumption of energy and chemicals, reduces the emission of waste, is environment-friendly and is beneficial to industrial production.
Detailed Description
The invention will be further illustrated with reference to examples.
Embodiment one: preparing a rare earth molecular sieve catalyst:
adding 15g of yttrium oxide into 300ml of distilled water, adding 100g of zeolite ZSM-5 molecular sieve, stirring to obtain suspension, adding 10% NaOH solution into the suspension, regulating pH to 9.0, stirring at room temperature for 1h, stirring at 85 ℃ for 2h, centrifuging, repeatedly washing the obtained solid with deionized water until no sodium ions exist, drying the obtained solid at 110 ℃ for 12h, grinding and sieving with a 100-mesh sieve to obtain the rare earth molecular sieve catalyst.
Embodiment two:
(1) Removing free water from L-lactic acid with content of 80-90% at normal pressure and 110 ℃ to obtain L-lactic acid with content of more than 99%;
(2) Sequentially adding 100g of L-lactic acid obtained in the step (1), 3g of rare earth molecular sieve catalyst and 80ml of dimethylbenzene into a reaction container, uniformly stirring, and heating to 130 ℃ for reaction for 10 hours to obtain a mixture containing lactide, lactic acid oligomer and dimethylbenzene;
(3) And (3) distilling the mixture containing lactide, lactic acid oligomer and xylene in the step (2) in vacuum to obtain the xylene, wherein the distillation temperature is 145 ℃, and the vacuum degree is-95 Kpa. Extracting the residue with 200ml of an equal volume of mixed solution of water and ethyl acetate, removing a water layer, distilling ethyl acetate to obtain a crude lactide product, recrystallizing the crude lactide product with 2 times of absolute ethyl alcohol, and drying at 45 ℃ under vacuum (-30 Pa) to obtain a refined lactide product.
Embodiment III:
(1) Removing free water from L-lactic acid with content of 80-90% at normal pressure and 110 ℃ to obtain L-lactic acid with content of more than 99%;
(2) Sequentially adding 100g of L-lactic acid obtained in the step (1), 1g of rare earth molecular sieve catalyst and 40ml of dimethylbenzene into a reaction container, uniformly stirring, and heating to 135 ℃ for reaction for 7 hours to obtain a mixture containing lactide, lactic acid oligomer and dimethylbenzene;
(3) And (3) distilling the mixture containing lactide, lactic acid oligomer and xylene in the step (2) in vacuum to obtain the xylene, wherein the distillation temperature is 145 ℃, and the vacuum degree is-95 Kpa. The residue was extracted with 140ml of an equal volume of a mixture of water and ethyl acetate, the aqueous layer was removed, and ethyl acetate was distilled off to obtain a crude lactide product. Recrystallizing the crude product with 3 times of absolute ethyl alcohol, and drying at 45 ℃ under vacuum (-30 Pa) to obtain the lactide refined product.
Embodiment four:
(1) Removing free water from L-lactic acid with content of 80-90% at normal pressure and 110 ℃ to obtain L-lactic acid with content of more than 99%;
(2) And (3) sequentially adding 100g of L-lactic acid obtained in the step (1), 2g of rare earth molecular sieve catalyst and 60ml of dimethylbenzene into a reaction vessel, uniformly stirring, and heating to 140 ℃ for reaction for 6 hours to obtain a mixture containing lactide, lactic acid oligomer and dimethylbenzene.
(3) And (3) distilling the mixture containing lactide, lactic acid oligomer and xylene in the step (2) in vacuum to obtain the xylene, wherein the distillation temperature is 145 ℃, and the vacuum degree is-95 Kpa. The residue was extracted with 160ml of an equal volume of a mixture of water and ethyl acetate, the aqueous layer was removed, and ethyl acetate was distilled off to obtain a crude lactide product. Recrystallizing the crude product with 2.5 times of absolute ethyl alcohol, and drying at 45 ℃ under vacuum (-30 Pa) to obtain the lactide refined product.
Fifth embodiment:
(1) Removing free water from L-lactic acid with content of 80-90% at normal pressure and 110 ℃ to obtain L-lactic acid with content of more than 99%;
(2) And (3) sequentially adding 100g of L-lactic acid obtained in the step (1), 2.5g of rare earth molecular sieve catalyst and 80ml of dimethylbenzene into a reaction vessel, uniformly stirring, and heating to 145 ℃ for reaction for 5 hours to obtain a mixture containing lactide, lactic acid oligomer and dimethylbenzene.
(3) And (3) distilling the mixture containing lactide, lactic acid oligomer and xylene in the step (2) in vacuum to obtain the xylene, wherein the distillation temperature is 145 ℃, and the vacuum degree is-95 Kpa. The residue was extracted with 180ml of an equal volume mixture of water and ethyl acetate, the aqueous layer was removed, and ethyl acetate was distilled off to obtain a crude lactide product. Recrystallizing the crude product with 3 times of absolute ethyl alcohol, and drying at 45 ℃ under vacuum (-30 Pa) to obtain the lactide refined product.
Example six:
(1) Removing free water from L-lactic acid with content of 80-90% at normal pressure and 110 ℃ to obtain L-lactic acid with content of more than 99%;
(2) And (3) sequentially adding 100g of L-lactic acid obtained in the step (1), 2g of rare earth molecular sieve catalyst and 80ml of dimethylbenzene into a reaction vessel, uniformly stirring, heating to 130 ℃ for reaction for 5 hours, and carrying out vacuum degree of-50 Kpa to obtain a mixture containing lactide, lactic acid oligomer and dimethylbenzene.
(3) And (3) distilling the mixture containing lactide, lactic acid oligomer and xylene in the step (2) in vacuum to obtain the xylene, wherein the distillation temperature is 145 ℃, and the vacuum degree is-95 Kpa. The residue was extracted with 180ml of an equal volume mixture of water and ethyl acetate, the aqueous layer was removed, and ethyl acetate was distilled off to obtain a crude lactide product. Recrystallizing the crude product with 3 times of absolute ethyl alcohol, and drying at 45 ℃ under vacuum (-30 Pa) to obtain the lactide refined product.
The reaction products of examples two to six were sampled and examined by chromatography to obtain the L-lactide content and the purity of L-lactide, and the experimental results are shown in Table 1 below. From the results in table 1, it can be seen that: the yield of the crude L-lactide product and the purity of the refined L-lactide product are both above 93 percent.
Determination method of L-lactide (L-lactide) (see the university of Tianjin Jiang Shouying Shuos treatise on the green purification of L-lactide, determination of 3.1L-lactide content): the gas chromatography method is characterized in that the correction factor of L-lactide (chromatographic standard) is calculated according to the correction factor normalization method. The sample (crude L-lactide/refined L-lactide) is dissolved and mixed with ethyl acetate, and the operation is carried out according to the set conditions of the chromatograph. And calculating the content of L-lactide (crude L-lactide/refined L-lactide) in the sample according to a correction factor normalization method.
And calculating the yield of the crude L-lactide product according to the content of the L-lactide in the crude L-lactide product. The content of the L-lactide in the L-lactide refined product is the purity of the L-lactide refined product.
The calculation method of the yield (%) of the L-lactide crude product comprises the following steps: l-lactide yield = 100% × (lactide content x mass of crude L-lactide)/(mass of theoretical lactide); the theoretical mass of lactide is the mass of lactic acid added at the beginning of the reaction x 72/90.
Table 1 results of lactide detection of reaction products of examples two to six
Claims (7)
1. A method for synthesizing lactide by one step catalyzed by a rare earth molecular sieve catalyst is characterized by comprising the following steps:
(1) Preparation of rare earth molecular sieve catalyst
Adding yttrium oxide into distilled water, adding zeolite ZSM-5 molecular sieve, stirring to obtain suspension, adding NaOH solution into the suspension, adjusting pH to 8.5-9.5, stirring at room temperature for 1-1.5 h, stirring at 80-90 ℃ for 1-3 h, centrifuging, repeatedly washing the obtained solid with deionized water until no sodium ions exist, drying the obtained solid, grinding and sieving with a 100-mesh sieve to obtain a rare earth molecular sieve catalyst; the mass ratio of the yttrium oxide to the zeolite ZSM-5 molecular sieve is 10-20: 100;
(2) Preparation of lactide
Adding L-lactic acid, the rare earth molecular sieve catalyst obtained in the step (1) and dimethylbenzene into a reaction container, uniformly stirring, heating to 120-160 ℃ and reacting for 5-10h to obtain a mixture containing lactide, lactic acid oligomer and dimethylbenzene; the reaction is carried out under normal pressure or under negative pressure with the vacuum degree of-40 to-50 Kpa; the mass ratio of the L-lactic acid to the rare earth molecular sieve catalyst is 1: (0.01-0.03); the volume ratio of L-lactic acid to xylene is 1: (0.4 to 1.0);
(3) Post-treatment
And (3) carrying out vacuum distillation on the mixture containing lactide, lactic acid oligomer and solvent xylene in the step (2), recovering the solvent xylene, and extracting residues to obtain a crude lactide product.
2. The method for synthesizing lactide in one step by using a rare earth molecular sieve catalyst according to claim 1, wherein the drying in the step (1) is as follows: drying at 100-120 ℃ for 10-15 h.
3. The method for synthesizing lactide by one step catalyzed by a rare earth molecular sieve catalyst according to claim 1, wherein the L-lactic acid in the step (2) is anhydrous L-lactic acid with a content of more than 99%.
4. The method for synthesizing lactide by one step catalyzed by a rare earth molecular sieve catalyst according to claim 3, wherein the anhydrous L-lactic acid with the content of more than 99% is prepared by heating and removing free water under normal pressure from L-lactic acid with the content of 80-90%.
5. The method for synthesizing lactide in one step by using a rare earth molecular sieve catalyst according to claim 1, wherein the extraction in the step (3) is as follows: extracting with water and ethyl acetate in equal volume, removing water layer, and distilling ethyl acetate to obtain crude lactide product.
6. The method for synthesizing lactide in one step by using a rare earth molecular sieve catalyst according to claim 1, wherein the crude lactide product obtained in the step (3) is recrystallized and dried to obtain refined lactide, and the recrystallization is as follows: recrystallizing with absolute ethanol.
7. The method for synthesizing lactide in one step by using a rare earth molecular sieve catalyst according to any one of claims 1 to 6, wherein the distillation temperature of the vacuum distillation in the step (3) is 145 ℃, the vacuum degree is-95 Kpa, and the solvent xylene recovered by the vacuum distillation is returned to the next batch for continuous use.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210846793.3A CN115141174B (en) | 2022-07-19 | 2022-07-19 | Method for synthesizing lactide by one step under catalysis of rare earth molecular sieve catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210846793.3A CN115141174B (en) | 2022-07-19 | 2022-07-19 | Method for synthesizing lactide by one step under catalysis of rare earth molecular sieve catalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115141174A CN115141174A (en) | 2022-10-04 |
| CN115141174B true CN115141174B (en) | 2023-10-03 |
Family
ID=83412456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210846793.3A Active CN115141174B (en) | 2022-07-19 | 2022-07-19 | Method for synthesizing lactide by one step under catalysis of rare earth molecular sieve catalyst |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115141174B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101747314A (en) * | 2009-12-25 | 2010-06-23 | 南开大学 | Process method for synthesizing L-lactide by molecular sieve catalytic pyrolysis method |
| CN108610323A (en) * | 2018-06-14 | 2018-10-02 | 中国科学院长春应用化学研究所 | A kind of preparation method of lactide |
| CN111057040A (en) * | 2019-11-05 | 2020-04-24 | 浙江工业大学 | Method for catalytically synthesizing lactide by using shape-selective zeolite supported catalyst |
| CN113385165A (en) * | 2021-07-14 | 2021-09-14 | 南京工业大学 | Yttria composite metal oxide catalyst and preparation method and application thereof |
-
2022
- 2022-07-19 CN CN202210846793.3A patent/CN115141174B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101747314A (en) * | 2009-12-25 | 2010-06-23 | 南开大学 | Process method for synthesizing L-lactide by molecular sieve catalytic pyrolysis method |
| CN108610323A (en) * | 2018-06-14 | 2018-10-02 | 中国科学院长春应用化学研究所 | A kind of preparation method of lactide |
| CN111057040A (en) * | 2019-11-05 | 2020-04-24 | 浙江工业大学 | Method for catalytically synthesizing lactide by using shape-selective zeolite supported catalyst |
| CN113385165A (en) * | 2021-07-14 | 2021-09-14 | 南京工业大学 | Yttria composite metal oxide catalyst and preparation method and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| （Synthesis of Lactide from Lactic Acid and Its Esters in the Presence of Rare-Earth Compounds;E. A. Poryvaeva等;Synthesis of Lactide from Lactic Acid and Its Esters in the Presence of Rare-Earth Compounds;第第53卷卷(第第3期期);P344-350 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115141174A (en) | 2022-10-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101198866B1 (en) | Recovery method of highly pure lactic acid and alkyl lactate | |
| US11926608B2 (en) | Synthesis method and device for rapidly producing lactide at high yield | |
| CN101255109B (en) | Technique for producing propenoic acid by dehydrating biomass lactic acid | |
| CN108569950B (en) | Method for preparing n-butanol by poly 3-hydroxybutyrate industrial crude product one-pot method | |
| CN111606875A (en) | Method for preparing furandicarboxylic acid monomer from bamboo biomass | |
| JP2002300898A (en) | Method for producing lactide from fermented lactic acid as raw material and method for producing polylactic acid | |
| Du et al. | The processing-module assembly strategy for continuous bio-oxidation of furan chemicals by integrated and coupled biotechnology | |
| CN115141174B (en) | Method for synthesizing lactide by one step under catalysis of rare earth molecular sieve catalyst | |
| KR101230907B1 (en) | Manufacturing Method of Lactide from Lactic acid | |
| CN113527703A (en) | Metal carbon-based coordination polymer, preparation method and application thereof in synthesis of 2, 5-furandimethanol | |
| CN113289692A (en) | Magnetic biomass solid catalyst and preparation and application thereof | |
| CN102850304B (en) | Furfural preparation method by using complex perovskites for one-step hydrolysis of xylan | |
| CN106831391A (en) | The method that chemicals is prepared by microalgae Direct Hydrothermal oxidation | |
| CN106536474A (en) | Novel lactic acid recovery process | |
| CN112341414A (en) | Method for preparing 2, 5-furandicarboxylic acid by two-step hydrolysis and oxidation of 5-chloromethyl furfural | |
| KR20220043676A (en) | An Esterification Method of Metal Organic Acid Salt and Carbon dioxide Conversion System Using the Same | |
| CN108129311B (en) | Method for preparing glycerol carbonate from carbon dioxide and glycerol | |
| CN110105324A (en) | The method that zinc Isoocatanoate catalyzes and synthesizes lactide | |
| CN107032999A (en) | A kind of method that utilization biological diesel oil byproduct glycerin produces triacetyl glycerine | |
| CN116272976B (en) | Method for preparing pentanediol by catalyzing furfural to hydrogenate through antibiotic fungus dreg derived bimetallic catalyst | |
| CN115806536B (en) | Method for preparing 5-hydroxymethylfurfural by solvent-free system | |
| CN112876438B (en) | Separation and purification method of high-purity 3-acetamido-5-acetylfuran | |
| CN103506140B (en) | Lactic acid catalyst for synthesizing and synthetic method | |
| CN108516931B (en) | Preparation method of alpha-ketoleucine calcium | |
| CN114907296B (en) | Method for efficiently catalyzing succinic acid to dehydrate to generate succinic anhydride |
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 | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |