The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 28, 1996
Filed:
Aug. 18, 1994
William G O'Brien, Newark, DE (US);
Lisa A Cariello, Springfield, PA (US);
Theodore F Wells, Downingtown, PA (US);
Ecological Chemical Products, Wilmington, DE (US);
Abstract
An integrated process for the manufacture of lactide from a solution of lactic acid in de-ionized water comprising the sequential steps: A. Dehydrating the aqueous lactic acid in at least two stages to effect condensation polymerization of the lactic acid and the formation of oligomers in which the average number of monomer units is 8-25, the dehydration stages being conducted in equipment fabricated from low ferrous materials; B. Thermally cracking the oligomers in the presence of depolymerization catalyst to form lactide vapor of which the average residence time within the cracking zone is less than 15 seconds; C. Condensing the lactide vapor and fractionally distilling the condensate to remove concentrated lactide as a liquid sidestream; and D. Subjecting the concentrated lactide sidestream to melt crystallization to separate purified lactide having an Acidity Potential less than 6.