| 摘要 |
The practicality of known depolymerization reactions in which there is a danger of building up adherent residues on heat transfer surfaces is greatly improved by performing the process under conditions that provide a driving force which assures that none of the feed material and none of any liquid or solid residue produced during the depolymerization of the feed material remains in contact with any heat transfer surface for a time sufficiently long to form any adherent solid residue on the surface. A preferred apparatus for achieving such a driving force includes a horizontal thin film evaporator, a controlled continuous input of liquid feed material, and continuous collection of desired reaction product and any residue that remains condensed throughout its passage through the reaction zone. The process is especially well adapted to producing cyclic ethylene tridecanedioate, cyclic ethylene dodecanedioate, and cyclopentadecanolide from higher molecular weight feed materials such as linear polymers of these materials, in greater than 90% yield in a single pass.
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