Patent ID: 6096673
Filing Date: 2000-08-01
Classification: B01J,C07D,Y02P

Abstract:
In a process for the production of 2,5-dihydrofuran by the isomerization of vinyl oxirane in the presence of an isomerization catalyst, the improvement for separating and removing oligomeric by-products for recovery of the catalyst which comprises:carrying out the isomerization with a catalyst consisting essentially ofa) an onium iodide,b) a Lewis acid which is at least one halide selected from the group consisting of the chlorides, bromides and iodides of zinc, cobalt and bismuth, andc) optionally, a donor ligandto obtain an initial reaction product mixture of the catalyst together with said dihydrofuran product and the oligomeric by-product from which substantially all lower boiling components are removed by distillation, and then recovering the catalyst by the steps of1) thoroughly mixing said initial product mixture with an extraction solvent selected from the group consisting of hydrocarbons and chlorinated hydrocarbons containing from 5 to 14 carbon atoms and permitting the mixture to stand and form two phases;2) separating the extraction solvent phase which contains the dissolved catalyst, and3) isolating and recovering the separated catalyst by distilling off said extraction solvent.