| 摘要 |
A PROCESS FOR OBTAINING OLIGOMERS OF POLYTETRAHYDROFURAN OR OF TETRAHYDROFURAN COPOLYMERS FROM A MEHTANOLIC CRUDE PRODUCT WHICH CONTAINS POLYTETRAHYDROFURAN OR TETRAHYDROFURAN OR TETRAHYDROFURAN COPOLYMERS AND IS ONTAINED 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 COPOLYMER,C)CONDENSING THE OLIGOMERS OF POLYTETRAHYDROFURAN OR OF TETRAHYDROFURAN COPOLYMERS OUT OF THE TOP FRACTION FROM STAGE B). |
