Bayer Aktiengesellschaft

Wilfried Niemeier

Gerhard Darsow

Gerd-Michael Petruck

Helmut Waldmann

Rudolf Braden

Otto Immel

Gerhard Friedhofen

Wolfgang Dummer

Christian Frohlich

In a process for producing aliphatic .alpha.,.omega.-diols comprising 4 to 12 C atoms from aliphatic .alpha.,.omega.-dicarboxylic acids comprising 4 to 12 C atoms, an oligoester of average chain length n=3 to n=4.5 and with an acid number of 40 to 60 mg KOH/g reaction mixture is first formed from a diol and a dicarboxylic acid, which oligoester is thereafter catalytically hydrogenated in the liquid phase. Hydrogenation is carried out continuously at 180 to 250.degree. C. and at an H.sub.2 pressure of 100 to 400 bar, over a pelletised catalyst which is free from Zn oxide and which comprises pressed powders of Cu, Mn and Al oxides with a content of at least one oxide of metals of subgroup VI of the periodic table of the elements (Mendeleev). The amount of H.sub.2 is 20 to 100 times the amount required stoichiometrically.

Process for producing aliphatic diols

Process for producing isocamphyl cyclohexanoles

In the preparation of a mixture of cyclohexylamine and dicyclohexylamine by catalytic hydrogenation of aniline at elevated temperature and elevated H.sub.2 pressure, use is made of reduced, support-free catalysts which comprise pressed element (hydr)oxide powders of Co, Mn, alkaline earth metals and element (hydr)oxide powders of elements of transition groups V and/or VI of the Periodic Table.

Process for preparing a mixture of cyclohexylamine and dicyclohexylamine

To prepare a mixture of cyclohexylamine and dicyclohexylamine by catalytic hydrogenation of aniline at elevated temperature and elevated H.sub.2 pressure, the catalyst system used comprises two reduced, unsupported catalysts A and B which are prepared from pressed element (hydr)oxide powders. Catalyst A comprises one or more of Fe, Co, Ni, also Mn, Cu and one or more of Ca, Sr, Ba. Catalyst B comprises one or more of Fe, Co, Ni, also Mn, Si and Mg.

A process for the preparation of aniline by hydrogenation of nitrobenzene in the gas phase in the presence of a catalyst containing a noble metal is described. The process can be carried out in an improved manner if the catalyst employed is palladium on graphite or petrol coke, as the support, containing 0.001-1% by weight of Pd, based on the total weight of the catalyst, it being possible for the catalyst also to contain, in addition to the Pd, 0.001-0.5% by weight of Ir and/or 0.001-0.3% by weight of Rh, all figures being based on the total weight of the catalyst.

Growing community of inventors

Krefeld, Germany

Wilfried Niemeier