Bayer Aktiengesellschaft

Heinz-Jurgen Alpers

Gerhard Darsow

Gerd-Michael Petruck

Bernd-Ulrich Schenke

Reinhard Thiel

Heinrich Steude

Ludwig Deibele

Gunther Lenz

Heinz Jorg Rosenbaum

Karl-Heinz Dietz

Karl-Heinz Heller

Siegfried Taurat

In a process for the preparation of aliphatic .alpha.,.omega.-diols of 4 to 12 carbon atoms from aliphatic .alpha.,.omega.-dicarboxylic acids of 4 to 12 carbon atoms, an oligo ester is first of all formed from diol and dicarboxylic acid and is subsequently subjected to catalytic hydrogenation in the liquid phase. The hydrogenation is carried out continuously at from 180.degree. to 250.degree. C. and at an H.sub.2 pressure of from 100 to 400 bar over a catalyst in piece form comprising compressed powders of Cu, Zn and Al oxides which do or do not contain at least one oxide of metals of the iron group of the Periodic Table of the Elements (Mendeleev) or of manganese. The quantity of H.sub.2 is from 20 to 100 times the stoichiometrically required quantity.

Process for the preparation of aliphatic .alpha., .omega.-diols

In a distillation column with vaporous sidestream removal, the vaporous product removed is condensed in a condenser. The vapor pipe provided for the removal of product opens into a dip tank of which the upper end is connected to the condenser while its lower end is connected to a discharge pump. Inert gas present in the condensate is returned to the column above the sidestream removal through an inert gas pipe arranged at the upper end of the condenser.

Distillation column with vaporous sidestream removal

In a process for the preparation of aqueous formaldehyde solutions consisting of the following steps:

Process for the preparation of aqueous formaldehyde solutions

The invention relates to a vanadium/phosphorus mixed oxide catalyst, a process for its preparation and its use for the preparation of maleic anhydride. The catalyst according to the invention is prepared by reacting a vanadium(V) compound with phosphoric acid and/or a compound forming phosphoric acid with heating, optionally in the presence of water, and subsequently treating the product obtained after the reaction with organic solvents and/or diluents having reducing activity, optionally in the presence of a promoter, at an elevated temperature.

Vanadium/phosphorus mixed oxide catalyst, process for its preparaton and

An improvement in the process for the preparation of formaldehyde by oxidative dehydrogenation of methanol with air in the presence of a silver catalyst at an elevated temperature wherein into the reactor in which the methanol is charged there is passed a stream of gas containing a halogen or halogen compound.

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Krefeld, Germany

Heinz-Jurgen Alpers