Abstract: Fermenter for producing a shear-thinning medium comprising a tank volume and a stirring arrangement having an improved distribution capacity or a more uniform shear stress.

Abstract: A process which isolates tetrahydrofuran from a stream of tetrahydrofuran, alkanol and high boilers, by: (a) separating off a first stream of tetrahydrofuran and alkanol as azeotrope in a first distillation stage; (b) feeding part of the first stream into a reactor for esterifying maleic anhydride, giving a second stream of tetrahydrofuran and monoalkyl maleate; (c) separating the second stream into a third stream of monoalkyl maleate and a fourth stream of tetrahydrofuran in a second distillation stage; (d) feeding the fourth stream of tetrahydrofuran from the second distillation stage and the part of the first stream from (a) which is not fed to the reactor into a third distillation stage to obtain a product stream of tetrahydrofuran and a sixth stream of tetrahydrofuran and alkanol; (e) recirculating the sixth stream from the third distillation stage into the first distillation stage or the reactor in (b).

Abstract: A process which isolates tetrahydrofuran from a stream of tetrahydrofuran, alkanol and high boilers, by: (a) separating off a first stream of tetrahydrofuran and alkanol as azeotrope in a first distillation stage; (b) feeding part of the first stream into a reactor for esterifying maleic anhydride, giving a second stream of tetrahydrofuran and monoalkyl maleate; (c) separating the second stream into a third stream of monoalkyl maleate and a fourth stream of tetrahydrofuran in a second distillation stage; (d) feeding the fourth stream of tetrahydrofuran from the second distillation stage and the part of the first stream from (a) which is not fed to the reactor into a third distillation stage to obtain a product stream of tetrahydrofuran and a sixth stream of tetrahydrofuran and alkanol; (e) recirculating the sixth stream from the third distillation stage into the first distillation stage or the reactor in (b).

Abstract: A process for preparing an aromatic amine by reacting a corresponding aromatic alcohol with an aminating agent selected from the group consisting of ammonia, primary amines and secondary amines, in the presence of hydrogen and a catalyst molding, at a temperature of from 60-300°. The catalyst molding comprises Zr, Pd and Pt and has an annular tablet form with an external diameter in the range from 2-6 mm, a height in the range from 1-4 mm and an internal diameter of from 1-5 mm or a topologically equivalent form with the same volume. Catalyst moldings comprising Zr, Pd and Pt are also provided. The catalyst molding has an annular tablet form with an external diameter in the range from 3-6 mm, a height in the range from 1-4 mm and an internal diameter of from 2-5 mm or a topologically equivalent form.