Kureha Corporation

Kureha Kagaku Kogyo K.k.

Kentaro Otawara

Kazuyuki Yamane

Naoki Hayashi

Tetsuo Ejiri

Tomohiro Hoshi

Tomoyuki Ogawa

Takuya Ohzawa

Tsutomu Kushida

Hiroaki c/o Iwaki Factory Kureha Corporation Ohashi

Masanori c/o Iwaki Factory Kureha Corporation Kobayashi

Yutaka c/o Iwaki Factory Kureha Corporation Igari

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.

Method for producing glycolide, which is provided with rectification step by means of gas-liquid countercurrent contact, and method for purifying crude glycolide

Disclosed is a process for purifying a hydroxycarboxylic acid, comprising: a crystallization step of subjecting a hydroxycarboxylic acid aqueous solution to crystallization for purification, a separation step of separating a hydroxycarboxylic acid crystal from a mother liquid, and a washing step of washing the hydroxycarboxylic acid crystal for further purification with a washing liquid, wherein the washing liquid is a hydroxycarboxylic acid aqueous solution. The purified or refined hydroxycarboxylic acid obtained through the above process is suitably used as a starting material for production of a polyhydroxycarboxylic acid. The above process is suitably included in a process for producing a cyclic ester and a process for producing a polyhydroxycarboxylic acid.

Process for purifying hydroxycarboxylic acid, process for producing cyclic ester, and process for producing polyhydroxycarboxylic acid

A method of refining a crystal of a crude cyclic ester comprises the steps of supplying the crude cyclic ester to a vertically extending cylindrical refiner ( ) from an inlet ( ) provided at a lower part of the refiner ( ), agitating the crude cyclic ester by an agitator provided in the refiner ( ) to make the crude cyclic ester flow upwardly, refining the crystals of the crude cyclic ester by counterflow-contact between the upflowing crude cyclic ester and a downflowing melted liquid containing a refined crystal component, and taking out refined crystals of the crude cyclic ester from an outlet ( ) provided at an upper part of the refiner ( ).

Method for purification of cyclic ester

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Tokyo, Japan

Kentaro Otawara