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:
Oct. 07, 1997
Filed:
Aug. 23, 1995
Charles Guthrie Moyers, Charleston, WV (US);
Michael Patrick Farr, Somerville, NJ (US);
Union Carbide Chemicals & Plastics Technology Corporation, Danbury, CT (US);
Abstract
Processes are disclosed for the recovery of 1,4-dioxanone by melt crystallization from a feed containing impurities capable of initiating the polymerization of 1,4-dioxanone, e.g., diethylene glycol. The processes of the present invention utilize melt crystallization in a cyclic process involving the steps of (i) crystallizing the 1,4-dioxanone out of the feed at a temperature below its melting point and removing a liquid residue containing a higher concentration of impurities, (ii) partially melting the crystallized 1,4-dioxanone to further remove impurities and (iii) thereafter, melting the remaining crystallized 1,4-dioxanone and recovering the melted product. The crystallization process can be repeated as required to achieve the desired purity. The purity of the product obtained is typically 99.5 wt %, 1,4-dioxanone or higher. The purified 1,4-dioxanone is useful, for example, as a monomer in the production of polydioxanone.