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AssigneeUnion Carbide Chemicals & Plastics Technology Corporation
InventorsCharles Guthrie Moyers, Michael Patrick Farr
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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.
A cyclic process for recovering 1,4-dioxanone from a feed containing 1,4-dioxanone and at least one impurity which is an initiator for the polymerization of 1,4-dioxanone, said process comprising:
Dependencies are inferred from the claim text.