| 摘要 |
<p>A process for working up residues containing dihydroxy compounds resulting from the preparation of polyesters, where(1) in a first stage there is esterification or transesterification of a dicarboxylic acid or esters thereof or ester-forming derivatives with a molar excess of a dihydroxy compound,(2) in at least one second stage there is polycondensation of the esterification product obtained in (1),(3) the vapors (a) and (b) resulting from the reactions in (1) and (2) respectively are subjected to a treatment to recover the starting materials,wherein the treatment to recover the starting materials is carried out in the presence of an alkali metal or alkaline earth metal compound in an amount of from 0.5 to 10% by weight, calculated as alkali metal or alkaline earth metal, based on the solids content of the vapors.</p> |
