CN117430581A - Method for preparing cyclic ester by one-step method - Google Patents

Method for preparing cyclic ester by one-step method Download PDF

Info

Publication number
CN117430581A
CN117430581A CN202210821836.2A CN202210821836A CN117430581A CN 117430581 A CN117430581 A CN 117430581A CN 202210821836 A CN202210821836 A CN 202210821836A CN 117430581 A CN117430581 A CN 117430581A
Authority
CN
China
Prior art keywords
metal
ester
catalyst
alpha
cyclic ester
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
Application number
CN202210821836.2A
Other languages
Chinese (zh)
Inventor
任杰
郁晓
张乃文
蔡沈阳
翁一明
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Maanshan Tongjieliang Biological Material Co ltd
Original Assignee
Maanshan Tongjieliang Biological Material Co ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Maanshan Tongjieliang Biological Material Co ltd filed Critical Maanshan Tongjieliang Biological Material Co ltd
Priority to CN202210821836.2A priority Critical patent/CN117430581A/en
Publication of CN117430581A publication Critical patent/CN117430581A/en
Pending legal-status Critical Current

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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Catalysts (AREA)

Abstract

The invention provides a method for preparing cyclic ester by a one-step method, which is used for catalyzing gas-phase transesterification and comprises the following steps: passing the gas phase containing the alpha-hydroxy ester over a solid catalyst; recovering the cyclic ester from the gaseous stream; the solid catalyst comprises at least one metal of titanium, zirconium, cesium, iron, zinc, and tin. The cyclic ester has high yield and high selectivity, the product is easy to purify, and the production cost is low, thus being suitable for large-scale industrialized production.

Description

Method for preparing cyclic ester by one-step method
Technical Field
The invention relates to a preparation method of an ester, in particular to a method for preparing a cyclic ester by a one-step method.
Background
Polylactic acid, also called as polylactide, is a polyester polymer obtained by polymerizing lactic acid as a main raw material, and is a novel biodegradable material. The production process of high molecular weight polylactic acid generally includes: lactic acid is dehydrated and condensed to generate lactic acid oligomer, the lactic acid oligomer is catalytically cracked to generate crude lactide, the crude lactide is purified to obtain polymer-grade lactide, and finally, the ring-opening polymerization reaction of the lactide is utilized to obtain the polylactic acid with high molecular weight.
Lactide (C) 6 H 8 O 4 ) White needle-like, with a melting point of 93-95 deg.C, a boiling point of 260 deg.C, a molecular weight of 144, and is easily soluble in chloroform, ethanol, and insoluble in water, and is an intermediate for preparing polylactic acid. The traditional lactide is mainly prepared by a two-step method, lactic acid is dehydrated to generate an oligomer, and the oligomer is subjected to cleavage cyclization to generate lactide. However, the traditional lactide preparation method has high energy consumption, low selectivity, high separation and purification difficulty and high manufacturing cost of lactide and polylactic acid, and a large amount of racemization products are generated. Wherein lactide is used as an intermediate for synthesizing polylactic acid, and the purity of the lactide directly influences the performance of the final polylactic acid product. Therefore, how to obtain high-purity lactide in an economically reasonable manner is a key technical means in the polylactic acid production process.
Disclosure of Invention
In view of the above-described drawbacks of the prior art, an object of the present invention is to provide a one-step process for preparing cyclic esters, which solves the problems of the prior art.
To achieve the above and other related objects, the present invention is achieved by the following technical means.
The invention provides a method for preparing cyclic ester by a one-step method, which is used for catalyzing gas-phase transesterification and comprises the following steps:
passing the gas phase containing the alpha-hydroxy ester over a solid catalyst; recovering the cyclic ester from the gaseous stream; the solid catalyst comprises at least one metal of titanium, zirconium, cesium, iron, zinc, and tin.
Preferably, the solid catalyst comprises a support, the metal being bonded to the support by a metal-oxygen-silicon covalent bond.
Preferably, the gas phase containing the alpha-hydroxy ester is a gas phase containing at least the alpha-hydroxy ester obtained by evaporating the alpha-hydroxy ester.
Preferably, the support comprises silica.
Preferably, the metal is on the surface of the carrier.
Preferably, the metal is incorporated in the body skeleton of the carrier.
Preferably, the metal is bound to the support by a titanium-oxygen-silicon covalent bond, a zirconium-oxygen-silicon covalent bond or a cesium-oxygen-silicon covalent bond.
Preferably, the support is a zeolite.
Preferably, the cyclic ester is a compound of formula i:
wherein R1, R2, R3 and R4 are each independently selected from hydrogen, C1-6 alkyl, C2-6 alkenyl, C6-10 aryl or C2-6 alkynyl.
Preferably, the cyclic ester is a compound of formula ii:
wherein R1 and R2 are each independently selected from hydrogen, C1-6 alkyl, C2-6 alkenyl, C6-10 aryl, or C2-6 alkynyl.
Preferably, the alpha-hydroxy ester is a C1-6 alkyl ester formed from a compound selected from the group consisting of lactic acid, glycolic acid, 2-hydroxybutyric acid, 2-hydroxy-3-butenoic acid, 4-methoxy-2-hydroxybutyric acid, and mandelic acid.
Preferably, the gas phase comprises at least one selected from inert gases, nitrogen and carbon dioxide.
Preferably, the catalytic gas phase transesterification is carried out at 180-300 ℃.
Preferably, the catalytic gas phase transesterification is carried out at a pressure of 0.1 to 10 bar. More preferably at a pressure of 0.5 to 1.5bar.
Preferably, the catalyst comprises at least one metal of titanium and zirconium in an amount of 0.01wt% to 20wt% of the catalyst mass, more preferably 0.5wt% to 10wt% of the catalyst mass.
Preferably, the cyclic ester is lactide and the alpha-hydroxy ester is a C1-6 alkyl ester formed from lactic acid or a mixture thereof. Preferably, the alpha-hydroxy ester is selected from at least one of methyl lactate, ethyl lactate, propyl lactate, butyl lactate and structural isomers thereof.
Preferably, the particle size of the solid catalyst is 100-1000 nm.
Preferably, the solid catalyst is obtained by impregnating a support with a metal precursor containing the metal and then calcining.
Preferably, the calcination temperature is 450-550 DEG C
The technical scheme of the invention has the beneficial effects that:
the invention provides a method for preparing cyclic ester by a one-step method, which has the advantages of high yield and high selectivity of cyclic ester, easy purification of products, low production cost and suitability for large-scale industrial production.
Detailed Description
Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present invention, which is described by the following specific examples.
Before the embodiments of the invention are explained in further detail, it is to be understood that the invention is not limited in its scope to the particular embodiments described below; it is also to be understood that the terminology used in the examples of the invention is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the invention. The test methods in the following examples, in which specific conditions are not noted, are generally conducted under conventional conditions or under conditions recommended by the respective manufacturers.
Where numerical ranges are provided in the examples, it is understood that unless otherwise stated herein, both endpoints of each numerical range and any number between the two endpoints are significant both in the numerical range. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition to the specific methods, devices, materials used in the embodiments, any methods, devices, and materials of the prior art similar or equivalent to those described in the embodiments of the present invention may be used to practice the present invention according to the knowledge of one skilled in the art and the description of the present invention.
The embodiment of the invention provides a specific one-step method for preparing cyclic ester, which is a catalytic gas-phase transesterification reaction and comprises the following steps:
passing the gas phase containing the alpha-hydroxy ester over a solid catalyst;
recovering the cyclic ester from the gaseous stream;
the solid catalyst comprises at least one metal of titanium, zirconium, cesium, iron, zinc, and tin.
In a preferred embodiment, the solid catalyst comprises a support, and the metal is bonded to the support by a metal-oxygen-silicon covalent bond.
In a preferred embodiment, the gas phase containing the alpha-hydroxy ester is a gas phase containing at least the alpha-hydroxy ester obtained by evaporating the alpha-hydroxy ester.
In a preferred embodiment, the support comprises silica.
In a preferred embodiment, the metal is on the surface of the support.
In a preferred embodiment, the metal is incorporated into the bulk framework of the support.
In a preferred embodiment, the metal is bound to the support by a titanium-oxygen-silicon covalent bond, a zirconium-oxygen-silicon covalent bond or a cesium-oxygen-silicon covalent bond.
In a preferred embodiment, the support is a zeolite.
In a preferred embodiment, the cyclic ester is a compound of formula i:
wherein R1, R2, R3 and R4 are each independently selected from hydrogen, C1-6 alkyl, C2-6 alkenyl, C6-10 aryl or C2-6 alkynyl.
In a preferred embodiment, the cyclic ester is a compound of formula ii:
wherein R1 and R2 are each independently selected from hydrogen, C1-6 alkyl, C2-6 alkenyl, C6-10 aryl, or C2-6 alkynyl.
In a preferred embodiment, the alpha-hydroxy ester is a C1-6 alkyl ester formed from a compound selected from the group consisting of lactic acid, glycolic acid, 2-hydroxybutyric acid, 2-hydroxy-3-butenoic acid, 4-methoxy-2-hydroxybutyric acid, and mandelic acid.
In a preferred embodiment, the gas phase comprises at least one selected from the group consisting of inert gas, nitrogen and carbon dioxide.
In a preferred embodiment, the catalytic gas phase transesterification reaction is carried out at 180 to 300 ℃. For example, it may be 180 ℃, 185 ℃, 190 ℃, 195 ℃, 200 ℃, 205 ℃, 210 ℃, 215 ℃, 220 ℃, 225 ℃, 230 ℃, 235 ℃, 240 ℃, 245 ℃, 250 ℃, 255 ℃, 260 ℃, 265 ℃, 270 ℃, 275 ℃, 280 ℃, 285 ℃, 290 ℃, 295 ℃ or 300 ℃.
In a preferred embodiment, the catalytic gas phase transesterification is carried out at a pressure of from 0.1 to 10 bar. More preferably at a pressure of 0.5 to 1.5bar. Such as 0.5bar, 0.6bar, 0.7bar, 0.8bar, 0.9bar, 1bar, 1.1bar, 1.2bar, 1.3bar, 1.4bar or 1.5bar.
In a preferred embodiment, the catalyst comprises at least one metal of titanium and zirconium in an amount of 0.01wt% to 20wt% of the catalyst mass, more preferably 0.5wt% to 10wt% of the catalyst mass, such as may be 0.5wt%, 0.8wt%, 1wt%, 1.2wt%, 1.5wt%, 1.8wt%, 2wt%, 2.3wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt% or 10wt%.
In a preferred embodiment, the cyclic ester is lactide and the alpha-hydroxy ester is a C1-6 alkyl ester formed from lactic acid or a mixture thereof.
In a preferred embodiment, the α -hydroxy ester is selected from at least one of methyl lactate, ethyl lactate, propyl lactate, butyl lactate and structural isomers thereof.
In a preferred embodiment, the solid catalyst has a particle size of 100 to 1000nm.
In a preferred embodiment, the solid catalyst is obtained by impregnating a support with a metal precursor comprising the metal and then calcining.
The method of claim 9, wherein the calcination temperature is 450-550 ℃. For example, it may be 450 ℃, 460 ℃, 470 ℃, 480 ℃, 490 ℃, 500 ℃, 510 ℃, 520 ℃, 530 ℃, 540 ℃, or 550 ℃.
The preparation method of the solid catalyst adopted in the embodiment of the application specifically comprises the following steps:
the metal precursor is dissolved in a solvent, and then amorphous silica gel or zeolite is impregnated therein, followed by calcination.
In a specific embodiment, the metal precursor is Ti-isopropanol and the solvent is isopropanol.
In a specific embodiment, the metal precursor is ZrO (NO). XH 2 O, the solvent is water.
In a specific embodiment, the metal precursor is SnCl 4 ·5H 2 O, the solvent is isopropanol.
In a specific embodiment, the metal precursor is Cs 2 CO 3 The solvent is toluene.
In a specific embodiment, the amorphous silica has a pore volume of 0.91 to 0.95cm 3 g -1 。
In a specific embodiment, the amorphous silica has an SBET of 275 to 295m 2 g -1 。
In a specific embodiment, the SiO 2 The gel was pre-dried to remove any excess water from the wells.
In a specific embodiment, the zeolite is MCM-41.
In the examples below, the conversion (C), selectivity (S) and yield (Y) in mol% are defined as follows:
conversion (%) = α -hydroxy ester conversion/α -hydroxy ester initial dose;
selectivity (%) = amount of α -hydroxy ester contained in the product/amount of α -hydroxy ester conversion;
yield (%) = conversion x selectivity.
Example 1
The embodiment uses TiO 2 /SiO 2 The catalyst produces lactide (denoted by LD) from methyl lactate (denoted by L-MLA).
In this example, a supported TiO was tested 2 /SiO 2 Catalyst in which the active component (Ti) is linked to amorphous SiO by Ti-O-Si bonds 2 The surface of the support was used for the synthesis of Lactide (LD) from L-methyl lactate.
Supported TiO 2 /SiO 2 The preparation method of the catalyst comprises the following steps:
dissolving proper amount of metal precursor (Ti-isopropanol) in isopropanol solvent, and then dissolving amorphous SiO 2 Gel (sbet=287 m) 2 g -1 Pore volume = 0.913cm 3 g -1 ) Wet impregnating to prepare the catalyst. The catalyst content was 0.05wt%.
The amount of solvent is selected so that the total volume of the impregnating solution (metal precursor and solvent) is approximately equal to the total pore volume of the catalyst.
Wherein SiO is 2 The gel was previously dried overnight at 105 ℃ to remove any excess water from the wells. Then the impregnation solution containing the metal precursor is added to the dried SiO 2 In the gel.
After all the impregnating solution is added to the SiO 2 After the gel, it was dried in an oven at 70℃for at least 12 hours. Then, the powder was calcined at 500℃for 3 hours at a heating rate of 10℃per minute to obtain active TiO containing necessary Ti-O-Si bonds 2 /SiO 2 A catalyst.
The fine catalyst powder is nanocrystallized to obtain a uniform powder of 100-1000 nm.
At the fixed positionTiO at different contact times was tested on a plug flow fixed bed reactor by varying the amount of catalyst 2 /SiO 2 Lactide production by catalyst, N 2 The concentration of L-MLA was 6vol%, and the reaction temperature was 220 ℃.
The results show that: there is a chemical equilibrium at about 60-90% conversion. The LD selectivity is very high, about 88-90%, with less than 60% conversion.
The reference experiment was performed using an equivalent amount of unimpregnated SiO 2 A support, and in the absence of a catalyst. For all reference experiments, a conversion of 2% was observed.
This example shows that the catalyst is catalytically active and can produce lactide with high selectivity.
Example 2
This example is an investigation of the effect of reaction temperature on the production of lactide from methyl lactate.
In this example, we studied the effect of reaction temperature on L-MLA production LD. For this, LD was prepared in the same manner as in example 1.
0.5wt% TiO at a temperature of 220-300 DEG C 2 /SiO 2 A catalyst.
The reaction conditions were as follows: 5.7vol% L-MLA in N 2 The reaction temperature is 220-300 ℃. Samples were taken after 2 hours of production.
The results are given in the table below.
The results in the table show that temperatures between 180℃and 260℃are suitable for the production of LD from L-LMA.
Example 3
This example is an investigation of the effect of catalyst loading on lactide production by methyl lactate
In this example, we have studied the use of TiO having different weight percentages 2 Loaded TiO 2 /SiO 2 Catalysts, for this purpose, of different weightsWeight percent TiO 2 /SiO 2 LD was prepared in the same manner as in example 1.
The reaction conditions were as follows: the reaction temperature was 220℃and 6vol% of L-MLA in N 2 Is a kind of medium.
The results are given in the table below.
This example shows different TiO 2 The load can be used for selectivity>80% of LD production.
Example 4
ZrO is used in this example 2 /SiO 2 The catalyst produces lactide from methyl lactate.
In this example, the use of ZrO is shown 2 And SiO 2 ZrO containing Zr-O-Si bonds between supports 2 /SiO 2 Catalyst (0.5 wt% ZrO) 2 Load) lactide was produced with L-MLA in the same manner as in example 1, but in this case the metal precursor was ZrO (NO). XH 2 O, the solvent was water, and then the catalyst was tested in the same manner as in example 1.
The reaction conditions were as follows: 6vol% L-MLA in N 2 In the above, the reaction temperature was 220 ℃.
After 2 hours of production, the L-MLA conversion was 44%, LD and ML 2 The selectivity of a was 85% and 15%, respectively, and no by-products were detected. The percentage of meso-LD was 20% of the total LD.
This example shows that ZrO containing Zr-O-Si bonds 2 /SiO 2 LD can be produced directly from L-MLA with high selectivity, but the percentage of meso-LD is significantly higher than that of TiO 2 SiO catalyst.
Example 5
Cs for display in this example 2 CO 3 /SiO 2 The catalyst produces lactide from methyl lactate.
In this example we demonstrate the use of Cs 2 CO 3 And SiO 2 Cs containing Cs-O-Si bonds between the carriers 2 CO 3 /SiO 2 Catalyst (0.5 wt% Cs) 2 CO 3 Load) lactide was produced with L-MLA in the same manner as in example 1, but in this case the solvent was toluene, and then the catalyst was tested in the same manner as in example 1.
The reaction conditions were as follows: 6vol% L-MLA in N 2 In the above, the reaction temperature was 220 ℃.
After 2 hours of production, the L-MLA conversion was 40%, LD and ML 2 The selectivity of a was 80% and 20%, respectively, and no by-products were detected. The percentage of meso-LD was 24% of the total LD.
This example shows that Cs contains Cs-O-Si bonds 2 CO 3 /SiO 2 The catalyst can directly produce LD from L-MLA with high selectivity, but the percentage of meso-LD is significantly higher than that of TiO 2 SiO catalyst.
Example 6
The use of SnO is demonstrated in this example 2 /SiO 2 The catalyst produces lactide from methyl lactate.
In this example, we tested the use of SnO 2 /SiO 2 Catalyst (10 wt% SnO) 2 ) LD was produced from L-MLA in the same manner as in example 1, but in this case, the metal precursor was SnCl 4 ·5H 2 O, the solvent is isopropanol.
The reaction conditions were as follows: 6vol% L-MLA in N 2 In the above, the reaction temperature was 220 ℃.
After 20 minutes of production, the L-MLA conversion was 32%, LD and ML 2 The selectivity of a was 88% and 11%, respectively. The percentage of meso-LD was 6% of the total LD. After 3 hours of production, the conversion of L-MLA was reduced to 12% and the selectivity of the product was unchanged.
This example shows that SnO is rapidly deactivated 2 /SiO 2 The catalyst is not suitable for the production of lactide from L-MLA.
Example 7
In this example, the production of lactide from methyl lactate using titanium zeolite is shown.
In this example, two titanium zeolites, namely Ti-beta and TS-1, which were tested to contain BEA and MFI topologies, respectively, were used to produce LD from L-MLA.
The reaction conditions were as follows: 6vol% L-MLA in Ar 2 In the above, the reaction temperature was 220 ℃.
The results are summarized in the following table
Example 8
This example demonstrates the use of TiO 2 The MCM-41 catalyst produces lactide.
TiO 2 Preparation method of MCM-41 catalyst: for this example, si-MCM-41 was used with a uniform pore width of 2.2nm, 926m 2 g -1 SBET of (C) and 0.582cm 3 Is used as a catalyst. The MCM-41 support was then impregnated with different mixtures of titanium isopropoxide in isopropanol by incipient wetness impregnation as described in example 1 to obtain different weight loadings of TiO on the MCM-41 2 (measured by ICP-OES) (T1O 2 /MCM-41). The impregnated catalyst was dried overnight at 80℃and calcined again at 500℃for 4 hours (heating rate: 10℃min) -1 ). The presence of Ti-O-Si was confirmed by FT-IR and XPS.
The final catalyst was tested in the same manner as in example 1 for the production of LD from L-MLA.
The reaction conditions were as follows: 6vol% L-MLA was sampled after 2 hours of operation in neon at 220 ℃.
The results are summarized in the following table.
This example shows SiO 2 The support may have an ordered mesoporous structure.
Example 9
This example shows the production of lactide from ethyl lactate.
TiO at 0.5wt% was tested in the same manner as in example 1 2 /SiO 2 LD is produced from L-ethyl lactate (L-ELA) in the presence of a catalyst.
The reaction conditions were as follows: 5vol% L-ELA in N 2 Samples were collected after 2 hours of production at 220 ℃.
GC analysis of the product stream showed 50% conversion of L-ELA and 87% and 11% selectivity of LD and linear dimer (EL 2A), respectively. meso-LD represents 4% of total LD.
Thus, ethyl lactate is also a very suitable ester starting material for the process.
Example 10
This example is the production of lactide from butyl lactate.
TiO at 0.5wt% was tested in the same manner as in example 1 2 /SiO 2 LD is produced from L-n-butyl lactic acid (L-BLA) in the presence of a catalyst.
The reaction conditions were as follows: 6vol% L-BLA in N 2 Samples were collected after 2 hours of production at 220 ℃.
GC analysis of the product stream showed a conversion of 30% for L-BLA and 80% and 13% for LD and linear dimer (EL 2A), respectively. The percentage of meso-LD was 3% of the total LD.
Butyl lactate is therefore also a very suitable ester starting material for the process.
Example 11
TiO is used in the present embodiment 2 /SiO 2 The catalyst produces glycolide from methyl glycolate.
In this example, the use of the same TiO as in example 1 is demonstrated 2 /SiO 2 0.5% by weight of a catalyst and glycolide was selectively produced from methyl 5-glycolate in the same manner as in example 1.
The feed solution consisted of 95/5vol% methyl glycolate (> 98%, TCI Europe) and o-xylene, respectively.
The reaction conditions were as follows: 6vol% methyl glycolate in N 2 In the above, the reaction temperature was 240 ℃. Run for 2 hoursAfter that, the methyl glycolate conversion was 52%, and the glycolide selectivity was 77%. The selectivity to linear dimer and trimer was 8% and 15%, respectively.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (10)

1. A process for the preparation of a cyclic ester by a one-step process, characterized by the catalytic gas phase transesterification reaction, comprising the steps of:
passing the gas phase containing the alpha-hydroxy ester over a solid catalyst;
recovering the cyclic ester from the gaseous stream;
the solid catalyst comprises at least one metal of titanium, zirconium, cesium, iron, zinc, and tin.
2. The method of claim 1, wherein the solid catalyst comprises a support, and the metal is bonded to the support by a metal-oxygen-silicon covalent bond; and/or the gas phase containing the alpha-hydroxy ester is a gas phase containing at least the alpha-hydroxy ester obtained by evaporating the alpha-hydroxy ester.
3. The method of claim 2, wherein the support comprises silica; and/or the metal is on the surface of the carrier; and/or the metal is incorporated in the bulk skeleton of the carrier; and/or the metal is bonded to the support via a titanium-oxygen-silicon covalent bond, a zirconium-oxygen-silicon covalent bond, or a cesium-oxygen-silicon covalent bond; and/or the carrier is zeolite.
4. The method of claim 1, wherein the cyclic ester is a compound of formula i:
wherein R1, R2, R3 and R4 are each independently selected from hydrogen, C1-6 alkyl, C2-6 alkenyl, C6-10 aryl or C2-6 alkynyl.
5. The method of claim 1, wherein the cyclic ester is a compound of formula ii:
wherein R1 and R2 are each independently selected from hydrogen, C1-6 alkyl, C2-6 alkenyl, C6-10 aryl, or C2-6 alkynyl.
6. The method of claim 1, wherein the α -hydroxy ester is a C1-6 alkyl ester formed from a member selected from the group consisting of lactic acid, glycolic acid, 2-hydroxybutyric acid, 2-hydroxy-3-butenoic acid, 4-methoxy-2-hydroxybutyric acid, and mandelic acid;
and/or the gas phase comprises at least one selected from inert gases, nitrogen and carbon dioxide;
and/or, the catalytic gas-phase transesterification is carried out at 180-300 ℃;
and/or the catalytic gas-phase transesterification is carried out at a pressure of 0.1 to 10bar, preferably 0.5 to 1.5 bar;
and/or the catalyst comprises at least one metal of titanium and zirconium in an amount of 0.01wt% to 20wt% of the catalyst mass, preferably 0.5wt% to 10wt% of the catalyst mass.
7. The method according to claim 1, characterized in that: the cyclic ester is lactide and the alpha-hydroxy ester is a C1-6 alkyl ester formed from lactic acid or a mixture thereof.
8. The method of claim 7, wherein the α -hydroxy ester is selected from at least one of methyl lactate, ethyl lactate, propyl lactate, butyl lactate, and structural isomers thereof.
9. The method according to claim 1, wherein the particle size of the solid catalyst is 100 to 1000nm; and/or the solid catalyst is obtained by impregnating a carrier with a metal precursor containing the metal and then calcining.
10. The method of claim 9, wherein the calcination temperature is 450-550 ℃.
CN202210821836.2A 2022-07-12 2022-07-12 Method for preparing cyclic ester by one-step method Pending CN117430581A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210821836.2A CN117430581A (en) 2022-07-12 2022-07-12 Method for preparing cyclic ester by one-step method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210821836.2A CN117430581A (en) 2022-07-12 2022-07-12 Method for preparing cyclic ester by one-step method

Publications (1)

Publication Number Publication Date
CN117430581A true CN117430581A (en) 2024-01-23

Family

ID=89555818

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210821836.2A Pending CN117430581A (en) 2022-07-12 2022-07-12 Method for preparing cyclic ester by one-step method

Country Status (1)

Country Link
CN (1) CN117430581A (en)

Similar Documents

Publication Publication Date Title
KR101376483B1 (en) Method for producing directly lactide from lactic acid and a catalyst used therein
RU2529489C2 (en) Method of carbonylation
EP3515901B1 (en) Process for preparing cyclic esters from alpha-hydroxy esters and catalysts used therein
KR20110106846A (en) Carbonylation process using bound silver and/or copper mordenite catalysts
KR20150018815A (en) Reduction catalysts
CA2876153A1 (en) Process for production of adipic acid from 1,6-hexanediol
US10597344B2 (en) Method for preparing 1,3-cyclohexanedimethanol
JPS63255253A (en) Production of amines
WO2015027184A1 (en) Production of 1,6-hexanediol from adipic acid
US7005536B2 (en) Method for producing diol derivatives
CN113045375A (en) Method for preparing 2-pentylanthracene from diamyl anthracene through transalkylation
KR101467202B1 (en) Shaped Catalyst For Direct Preparation of Lactide from Lactic Acid and Preparation of the Shaped Catalyst
CN117430581A (en) Method for preparing cyclic ester by one-step method
JP2004131411A (en) Method for purifying glycolic acid ester and method for producing glycolic acid ester
KR101577362B1 (en) Preparation method of 1,4-cyclohexanedimethanol
EP1553076A1 (en) Process for producing diol derivative
WO2009110217A1 (en) Hydroxyapatite with silver supported on the surface thereof
CN112495439B (en) Photocatalytic catalyst, preparation method thereof and preparation method of vitamin A palmitate
JP2016529220A (en) Process for producing furan and its derivatives
CN112794839B (en) Preparation method of glycolide
KR102635637B1 (en) Catalyst for Depolymerisation of Polyethylene Terephthalate and Preparing Method of the Same
JP2004182645A (en) Method for manufacturing glycolic ester
KR101786910B1 (en) Preparation method of 1,4-cyclohexanedimethanol
JP2013527835A (en) Method for producing lactone
JP2004203743A (en) Method for stabilizing glycolic acid ester and stabilized composition

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