| 摘要 |
A process for obtaining oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers from a methanolic crude product which contains polytetrahydrofuran or tetrahydrofuran copolymers and is obtained in the transesterification of the mono- and/or diesters of polytetrahydrofuran or tetrahydrofuran copolymers with methanol, which comprises a) removing the majority of the methanol from the crude product in a first distillation stage, b) separating the resulting bottom product by distillation into a top fraction comprising the oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers, and polytetrahydrofuran or tetrahydrofuran copolymer, c) condensing the oligomers of polytetrahydrofuran or of tetrahydrofuran copolymers out of the top fraction from stage b).
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