Patent ID: 9186599
Filing Date: 2015-11-17
Classification: B01D,C07D

Abstract:
1. A process for isolating tetrahydrofuran from a stream comprising tetrahydrofuran, alkanol and high boilers, which process comprises: (a) separating off a first stream comprising tetrahydrofuran and alkanol as azeotrope from the stream comprising tetrahydrofuran, alkanol and high boilers in a first distillation stage, (b) feeding at least part of the first stream comprising tetrahydrofuran and alkanol as azeotrope into a reactor for esterifying maleic anhydride, giving a second stream comprising monoalkyl maleate, tetrahydrofuran, optionally alkanol, and optionally unreacted maleic anhydride, (c) separating the second stream comprising monoalkyl maleate, tetrahydrofuran, optionally alkanol, and optionally unreacted maleic anhydride, into a third stream comprising monoalkyl maleate and a fourth stream comprising tetrahydrofuran and optionally alkanol in a second distillation stage, (d) feeding the fourth stream comprising tetrahydrofuran and optionally alkanol from the second distillation stage and the part of the stream comprising tetrahydrofuran and alkanol as azeotrope from said (a) separating which is not fed to the reactor into a third distillation stage in which a product stream comprising essentially tetrahydrofuran and a fifth stream comprising tetrahydrofuran and alkanol are obtained, (e) recirculating the fifth stream comprising tetrahydrofuran and alkanol from the third distillation stage to the first distillation stage or to the reactor in said (b) feeding.