- METHOD FOR PRODUCING CYCLIC ESTER
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In a method for producing a cyclic ester according to an embodiment of the present invention, a mixture (I) containing an aliphatic polyester, a specific polyalkylene glycol diether, and a sulfonic acid compound as a thermal stabilizer is prepared and heated in predetermined conditions to obtain a mixture (II) in a state of solution. Furthermore, heating of the mixture (II) is continued to distill, together with the polyalkylene glycol diether, a cyclic ester formed by the depolymerization reaction, and thus a distillate (III) is obtained. The cyclic ester is recovered from the distillate (III). At this time, a specific solubilizing agent is added to at least one of the mixture (I) or (II). In this production method, the sulfonic acid compound as the thermal stabilizer is contained in the mixtures (I) and (II) and the distillate (III).
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Paragraph 0113-0115
(2020/12/25)
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- PROCESS FOR PREPARING GLYCOLIDE
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According to the present invention a process is provided for producing glycolide which comprises contacting glycolaldehyde dimer with an oxidizing agent to produce a glycolide product.Preferably, the process is carried out in an aprotic environment, such as in a reaction mixture comprising the glycolaldehyde dimer, the oxidizing agent, the glycolide product and an aprotic solvent.
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Page/Page column 14-17
(2020/07/05)
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- Preparation method of glycolide
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The invention provides a preparation method of glycolide, which comprises the following steps: adding methyl glycolate and stannous octoate, stirring, continuously introducing nitrogen, heating to 150-180 DEG C to start reaction, heating to 200-210 DEG C to continue the reaction, keeping the temperature of the distillation head above the boiling point of methanol in the reaction process, ending the reaction when no methanol is evaporated, thereby obtaining the glycolide, wherein the generated yellowish-brown solid is the methyl glycolate oligomer, heating the methyl glycolate oligomer to 240-260 DEG C, keeping the vacuum degree in the reaction system at 1.0-1.5 kPa, reacting to obtain a faint yellow crystal which is a glycolide crude product, taking out the glycolide crude product, washingwith distilled water, and recrystallizing the washed glycolide crude product to obtain glycolide. According to the preparation method of glycolide provided by the invention, the intermediate productof ethylene glycol prepared by coal chemical industry is used as a raw material to obtain high-purity glycolide, the process is simple, and industrial promotion is facilitated.
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Paragraph 0037-0041; 0053-0056
(2020/12/15)
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- METHOD FOR PRODUCING GLYCOLIDE
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PROBLEM TO BE SOLVED: To provide a method for producing glycolides, with which glycolides can be produced more rapidly. SOLUTION: The method for producing glycolides comprises: an oligomer preparation step for obtaining a glycolic acid oligomer by heating an aqueous glycolic acid solution and by the dehydropolycondensation of the glycolic acid contained in the aqueous glycolic acid solution; and a depolymerization step for obtaining a glycolide by depolymerization of the glycolic acid oligomer in the presence of divalent iron ions. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0083-0093
(2019/10/30)
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- METHOD FOR PRODUCING GLYCOLIDE
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PROBLEM TO BE SOLVED: To provide a method for producing glycolides, with which glycolides can be produced more rapidly. SOLUTION: The method for producing glycolides comprises: a step of adding metal iron to an aqueous glycolic acid solution; a step for obtaining a glycolic acid oligomer by the dehydropolycondensation of a glycolic acid contained in the aqueous glycolic acid solution having the metal iron added thereto; and a step for obtaining a glycolide by heating the glycolic acid oligomer for depolymerization. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
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Paragraph 0062-0068
(2019/10/30)
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- METHOD FOR PRODUCING a-HYDROXYCARBOXYLIC ACID DIMERIC CYCLIC ESTER
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Provided is a method for producing a high purity α-hydroxycarboxylic acid dimeric cyclic ester while heavy-component formation from an α-hydroxycarboxylic acid oligomer is suppressed. An α-hydroxycarboxylic acid dimeric cyclic ester is obtained by performing a depolymerization reaction in the coexistence of an inorganic acid or an inorganic acid salt or a mixture thereof; and an organophosphorus compound.
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Paragraph 0097-0103
(2019/11/11)
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- Catalytic Gas-Phase Cyclization of Glycolate Esters: A Novel Route Toward Glycolide-Based Bioplastics
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A catalytic process to produce glycolide, the cyclic dimer of glycolic acid (GA), is proposed. Glycolide is the key building block of the biodegradable plastic polyglycolic acid. Instead of the current industrial two-step route, which involves the polycondensation of GA and a subsequent backbiting reaction, a new route based on the gas-phase transesterification of methyl glycolate (MGA) over a fixed catalyst bed is presented. With specific supported TiO2 catalysts, a high glycolide selectivity of 75–78 % can be achieved at the thermodynamically-limited equilibrium conversion of MGA (54 % at 300 °C, 5.6 vol% MGA, 1 atm). The absence of solvent and the continuous nature of the process should allow for easy product separation and recycling of unconverted esters, while the few side-products, i. e. linear alkyl glycolate dimers and trimers seem recoverable via methanolysis. The reaction is compared to the cyclization of other α-hydroxy esters, such as methyl lactate to lactide, over the same catalysts, in terms of kinetics and thermodynamics. The absence of a methyl substitution on the α-carbon seems to lead to faster cyclization kinetics of MGA when compared to methyl lactate or the double-substituted methyl-2-hydroxy-isobutyrate. Contrarily, glycolide production is less favored thermodynamically compared to lactide. The absence of glycolide decomposition at temperatures up to 300 °C however allows to increase equilibrium conversion by taking the endergonic reaction to higher temperatures.
- De Clercq, Rik,Makshina, Ekaterina,Sels, Bert F.,Dusselier, Michiel
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p. 5649 - 5655
(2018/12/04)
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- Synthetic method of glycolide
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The invention discloses a synthetic method of glycolide. The synthetic method comprises the following steps: placing chloroacetyl chloride and glycollic acid molten in a heating manner into a reactor,adding carbonate, reacting, and obtaining chloracetylglycollic acid; and mixing chloracetylglycollic acid and carbonate, stirring, decompression distilling, and distilling out a glycolide crude product, wherein the reaction formula is shown in the description. The raw materials chloroacetyl chloride, glycollic acid and carbonate used in the synthetic method are massively available in the market,and no massive acidic waste water is produced in the synthesis process, so that the environmental pollution is greatly reduced. According to the synthetic method, no organic solvent is used, so that not only can the cost be reduced, but also the environmental pollution is avoided, and the harm on the body of the working personnel is reduced. Chloroacetyl chloride used in the invention is low in price; compared with the traditional process completely using glycolic acid, the production cost is greatly reduced; meanwhile, no catalyst is needed, so that the production operation is simpler. The yield of glycolide is correspondingly increased.
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Paragraph 0022; 0025; 0030; 0035
(2018/11/22)
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- Mild Access to N-Formylation of Primary Amines using Ethers as C1 Synthons under Metal-Free Conditions
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A new synthetic protocol has been developed for the synthesis of N-formamide derivatives using ethers as a C1 synthon under metal-free reaction conditions. The reaction is proposed to proceed through C?H functionalization, C?O cleavage, and C?N bond formation. This protocol is applicable to a variety of primary amines resulting in N-formamides in moderate to good yields. 1,4-dioxane was chosen as best C1 synthon after screening with various ethers. Mechanistic studies disclosed that the reaction proceeds through a radical pathway. While using α-amino ketones a α-alkylation product was formed rather than formylation. By replacing dioxane with Tetramethylethylenediamine (TMEDA) under standard conditions also gave the N-formamide derivatives in moderate yields. (Figure presented.).
- Mutra, Mohana Reddy,Dhandabani, Ganesh Kumar,Wang, Jeh-Jeng
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p. 3960 - 3968
(2018/09/10)
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- METHOD FOR PRODUCING GLYCOLIDE, WHICH IS PROVIDED WITH RECTIFICATION STEP BY MEANS OF GAS-LIQUID COUNTERCURRENT CONTACT, AND METHOD FOR PURIFYING CRUDE GLYCOLIDE
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A method for producing glycolide provided with: step (1) wherein a GAO composition, which preferably contains a high-boiling-point organic solvent or a solubilizing agent, is supplied into a reactor and heated to a temperature at which a depolymerization reaction of the GAO occurs; step (2) wherein the heating is continued to subject the GAO to the depolymerization reaction, thereby producing glycolide; step (3) wherein glycolide is distilled out of the reactor; step (4) wherein the distillate is introduced into a rectifier and is rectified by means of gas-liquid countercurrent contact; and step (5) wherein glycolide is recovered. A method for purifying crude glycolide provided with: step (i) wherein a crude glycolide composition, which preferably contains a high-boiling-point organic solvent or a solubilizing agent, is supplied into a reactor and heated so that glycolicde is distilled; step (ii) wherein the distillate is introduced into a rectifier and is rectified by means of gas-liquid countercurrent contact; and step (iii) wherein glycolide is recovered. A glycolide producing apparatus and a crude glycolide purifying apparatus, each of which is provided with a reactor and a rectifier.
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Paragraph 0163; 0167; 0176
(2015/11/03)
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- PROCESS FOR PREPARING CYCLIC ESTERS AND CYCLIC AMIDES
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The invention relates to a process for preparing a cyclic ester or a cyclic amide, comprising the step of: contacting at least one hydroxycarboxylic acid and/or at least one amino-carboxylic acid; or an ester, or salt thereof; wherein said hydroxycarboxylic acid is a 2-hydroxycarboxylic acid,or a 6–hydroxycarboxylic acid; and wherein said amino carboxylic acid is a 2-amino-carboxylic acid or a 6-amino-carboxylic acid; with at least one acidic zeolite comprising: - two or three interconnected and non-parallel channel systems, wherein at least one of said channel systems comprises 10-or more-membered ring channels; and a framework Si/X2 ratio of at least 24 as measured by NMR; or - three interconnected and non-parallel channel systems, wherein at least two of said channel systems comprise 10-or more-membered ring channels; and a framework Si/X2 ratio of at least 6 as measured by NMR; wherein each X is Al or B, and wherein the process is performed at a pressure between 0.5 and 20 bar.
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Page/Page column 30-32
(2014/08/20)
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- Preparation and application of Hydroxyacetic Acid Esters as Methanol-Gasoline additives
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In this paper, hydroxyacetic acid esters (glycolic esters) were synthesized and used as phase stabilizer and saturation vapour pressure depressor of methanol-gasoline. The results show that the stabilities of the blends depend on the length of the glycoli
- Jiang, Xiaoyan,Tang, Ying
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p. 8447 - 8450
(2013/11/06)
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- PROCESS FOR THE MANUFACTURE OF A CYCLIC DIESTER OF AN ALPHA-HYDROXYACID
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Process for the manufacture of a cyclic diester of an alpha-hydroxyacid comprising heating the alpha-hydroxyacid at a temperature from 100 to 250°C in the presence of at least one polyol and of at least one catalyst selected from the group consisting carboxylates and alkoxides of Ti, Zr, Al and Sn.
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Page/Page column 7-8
(2012/02/02)
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- Biodegradable triblock copolymers for implantable devices
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The present invention is directed to polymeric materials made of biodegradable, bioabsorbable triblock copolymers and implantable devices (e.g., drug-delivery stents) containing such polymeric materials. The polymeric materials may also contain at least one therapeutic substance. The polymeric materials are formulated so as to improve the mechanical and adhesion properties, degradation, biocompatibility and drug permeability of such materials and, thus, implantable devices formed of such materials.
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- Method for purifying glycolide
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The invention pertains to a method for purifying glycolide comprising the step of distilling crude glycolide under reflux using a distillation column having a ratio S/CxL > 1.1 and S2/C2L > 0.4 m, wherein S stands for the inner surface of the column in m2; L x C stands for the outer surface of the column in m2, wherein L stands for the length of the column in m; and C stands for the average circumference of the column in m, to obtain glycolide having a purity expressed as a turbidity 10 NTU as measured by the method according to DIN 27027 /ISO 7027 of a solution of 1 g of said glycolide in 5 ml of acetone.
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Page/Page column 5
(2008/06/13)
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- Method for producing diol derivatives
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A method of producing a diol derivative efficiently and to high purity is provided. Specifically, the present invention relates to a method of producing a diol derivative having, as a fundamental step, a step of obtaining an α-hydroxycarboxylic acid ester by reacting (i) one or more 1,2-diols or (ii) a 1,2-diol and a primary alcohol as starting material(s) with oxygen in the presence of a catalyst comprising metal loaded on a carrier.
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- Process for the preparation of cyclic esters and method for purification of the same
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The present invention provides a process for production of a cyclic ester by depolymerization of an aliphatic polyester. In the process, a mixture containing the aliphatic polyester and a specific polyalkylene glycol ether, which has a boiling point of 230-450° C. and a molecular weight of 150-450, is heated under normal or reduced pressure to a temperature at which depolymerization of the aliphatic polyester takes place. Then, a substantially homogeneous solution phase, consisting of the melt phase of the aliphatic polyester and the liquid phase of the polyalkylene glycol ether, is formed. Heating of the solution phase is continued to form the cyclic ester by depolymerization and distil out the cyclic ester together with the polyalkylene glycol ether, and then the cyclic ester is recovered from the distillate. The present invention also provides a process for purification of a crude cyclic ester by use of the specific polyalkylene glycol ether described above.
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Page/Page column 14-15
(2010/11/30)
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- Controlled-release formulations of interleukin-2
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Shipping fever, and other stress-related diseases in livestock, are treated by administration of a microencapsulated composition comprising IL-2 conjugated with a polyoxyethylene polymer, and mixed with a release-modulating amount of humen serum albumin. The microcapsules are administered parenterally, and release an effective amount of conjugated IL-2 continuously over a period of 14-30 days. These microcapsules are also effective in the treatment of cancer in mammals.
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- Process for preparing highly pure cyclic esters
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A process for making highly pure cyclic esters by heating a copolymer of α-hydroxy acid or its ester on a thermally stable polyether core.
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- Condensation of Glycolic, Lactic and 2-Hydroxybutanoic Acids during Heating and Identification of the Condensation Products by GLS-MS
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Glycolic, lactic and 2-hydroxybutanoic acids are partly converted to various condensation products during heating.This conversion was studied at 100 deg C and 125 deg C by identifying the trimethylsilylated products consisted of both linear (dimers and trimers) and cyclic (dimers) structures.The influence of the condensation on the recovery and purification of the hydroxy acids by distillation is discussed.
- Alen, Raimo,Sjoestroem, Eero
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p. 633 - 636
(2007/10/02)
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