Abstract: A mixture containing mixture one or more amines, water, low-boilers and high-boilers, is fractioned in a process wherein (i) low-boilers are separated from the mixture by distillation, (ii) high-boilers are separated from the mixture by distillation, (iii) the mixture is extracted with a sodium hydroxide solution to form an aqueous, sodium-hydroxide-containing first phase and an aqueous-organic, amine-containing second phase, and (iv) the aqueous-organic second phase is distilled to form an amine/water azeotrope and an essentially anhydrous amine, and the amine/water azeotrope is recycled to the extraction step (iii).

Abstract: A process for hydrogenating an unsaturated heterocyclic compound or a mixture of two or more thereof by contacting the unsaturated heterocyclic compounder the mixture of two or more thereof with a hydrogen-containing gas in the presence of a catalyst comprising as active metal at least one metal from transition group VIII of the Periodic Table, applied to a support, wherein the support has macropores.

Abstract: The invention relates to a process for preparing essentially formic acid-free N-alkyl-N′-methylalkyleneureas of the formula with R1=H or CH3, R2=CnH2n+1 with n=1-4 and x=0 or 1, from the corresponding alkyleneureas by reaction with monomeric or polymerized formaldehyde in the presence of formic acid. This entails feeding the mixture, obtained in the reaction, of N-alkyl-N′-methylalkyleneurea and formic acid to the upper region of a distillation column, distilling without further additions and removing essentially formic acid-free N-alkyl-N′-methylalkyleneurea in the lower region of the column.

Abstract: In a process for the suspension hydrogenation of an anthraquinone compound or a mixture of two or more thereof in a reactor in which there are present the working solution in which at least one catalyst is suspended and, in addition, a hydrogen-containing gas phase, the working solution and the gas phase are, in the reactor, passed at least partly through a fitting having openings or channels whose hydraulic diameter is from 0.5 to 20 mm, preferably from 1 to 10 mm, particularly preferably from 1 to 3 mm.

Abstract: A process for preparing polytetrahydrofuran, polytetrahydrofuran copolymers or diesters or monoesters of these polymers comprises polymerizing tetrahydrofuran in the presence of at least one telogen and/or comonomer over a heterogeneous catalyst comprising hectorite.

Abstract: In a process for preparing polytetrahydrofuran, polytetrahydrofuran copolymers or diesters or monoesters thereof comprises polymerizing tetrahydrofuran in the presence of at least one telogen and/or comonomer over an acid-activated calcium montmorillonite as catalyst, the calcium montmorillonite has a BET surface area of at least 300 m2/g, an acidity of at least 0.02 mmol/g at pKa<−3 and a pore volume of at least 0.40 cm3/g for pore sizes in the range from 30 to 200 Å.

Abstract: In a process for preparing polytetrahydrofuran, polytetrahydrofuran copolymers or diesters or monoesters thereof by polymerization of tetrahydrofuran in the presence of at least one telogen and/or comonomer over acid-activated montmorillonite catalysts, the montmorillonite catalyst after acid activation has a ratio of montmorillonite structure to the sum of muscovite and kaolin structures, determined from the intensities of the reflections at 2&thgr;=5.5° for montmorillonite, 2&thgr;=9.0° for muscovite and 2&thgr;=12.5° for kaolin measured in the X-ray powder pattern, of at least 5:1.

Abstract: In a process for preparing polytetrahydrofuran, tetrahydrofuran copolymers, diesters or monoesters of these polymers having a low color number by polymerization of tetrahydrofuran in the presence of at least one telogen and/or comonomer over a heterogeneous catalyst, the polymerization is carried out in the presence of hydrogen.