Process for the preparation of cyclic esters and method for purification of the same
申请人:——
公开号:US20030191326A1
公开(公告)日:2003-10-09
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.
A Convenient Catalytic Method for the Synthesis of Ethers from Alcohols and Carbonyl Compounds
作者:Yasuyuki Fujii、Hisakazu Furugaki、Shinji Yano、Katsumi Kita
DOI:10.1246/cl.2000.926
日期:2000.8
Unsymmetrical ethers are obtained in excellent yields by the catalytic etherification of alcohols with ketones or aldehydes in the presence of Pd/C under an atmospheric pressure of hydrogen when water produced by the reaction is continuously removed by bubbling hydrogen through the reaction mixture.
PROCESS FOR THE PREPARATION OF CYCLIC ESTERS AND METHOD FOR PURIFICATION OF THE SAME
申请人:KUREHA KAGAKU KOGYO KABUSHIKI KAISHA
公开号:EP1310496A1
公开(公告)日:2003-05-14
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.
The invention provides a production process of glycolide comprising the respective steps of: Step 1 of heating a mixture containing a glycolic acid oligomer and a high boiling polar organic under normal or reduced pressure to reflux the mixture and at that time, conducting a total reflux operation in a reflux time within a range of 0.1 to 20 hours under conditions that substantially the whole amount of a distillate distilled out of a reflux system containing the mixture is refluxed into the reflux system; Step 2 of heating the mixture after the total reflux operation or a mixture obtained by adding the high boiling polar organic solvent to a glycolic acid oligomer component recovered from the mixture after the total reflux operation to conduct depolymerization; and Step 3 of collecting glycolide from a co-distillate.