PRODUCTION OF LACTIDE

PURPOSE: To simply and economically obtain a high-purity lactide by polycondensing lactic acid and then thermally decomposing the resultant polylactic acid under specific conditions. CONSTITUTION: Purified lactic acid or crude lactic acid obtained in a fermenting step, etc., or containing inorganic...

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Bibliographic Details
Main Authors YUMOTO ISAO, MORITA MIKIO, HIRAMA YASUKO, IKEDA KOJI
Format Patent
LanguageEnglish
Published 14.05.1996
Edition6
Subjects
APPARATUS THEREFOR
CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY
CHEMISTRY
GENERAL METHODS OF ORGANIC CHEMISTRY
HETEROCYCLIC COMPOUNDS
METALLURGY
ORGANIC CHEMISTRY
PERFORMING OPERATIONS
PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
THEIR RELEVANT APPARATUS
TRANSPORTING
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Summary:PURPOSE: To simply and economically obtain a high-purity lactide by polycondensing lactic acid and then thermally decomposing the resultant polylactic acid under specific conditions. CONSTITUTION: Purified lactic acid or crude lactic acid obtained in a fermenting step, etc., or containing inorganic salts is vacuum distilled and dehydrated, preferably at 60-100 deg.C to provide a concentrated lactic acid, which is then usually polycondensed at 100-200 deg.C (preferably 100-180 deg.C) under <=30mmHg (preferably <=10mmHg) for 5-20hr to afford polylactic acid having 2000-20000 weight- average molecular weight. Ferrous oxide as a catalyst in an amount of <=5wt.% is then added to the resultant polymer and catalytic thermal decomposition of the polymer is usually carried out at 200-300 deg.C (preferably 230-300 deg.C) under 1-30mmHg (preferably 1-15mmHg) for 1-3hr. Thereby, the objective lactide is obtained.
Bibliography:Application Number: JP19940256528