Bayer Aktiengesellschaft

Heinrich Steude

Kaspar Hallenberger

Helmut Waldmann

Hans-Joachim Traenckner

Claus H Wulff

Klaus Nachtkamp

Rudiger Schubart

Eckart Kranz

Gunther Weymans

Christian Rasp

Wolfram Wagner

Georg Ronge

Oswald Wilmes

Peter Siegle

Jurgen Hinz

Zoltan Kricsfalussy

Franz Ferdinand Rhiel

Herbert Schwarz

Jurgen Dahmer

Ludwig Deibele

Dieter Schleenstein

Johan Vaes

Kurt-Peter Meurer

Heinz-Jurgen Alpers

Tony Van Osselaer

Wilfried Litz

Klaus Elgeti

Stephan Kabelac

Ignace Hooftman

Siegfried Taurat

Frank Quaeyhaegens

This present invention relates to a process for thermally cracking carbamic acid esters into the corresponding isocyanate and hydroxyl compounds in the liquid phase, wherein the reaction proceeds as a reactive rectification in the stripping zone of a column and in an inert, high-boiling solvent, which acts as a buffer to keep the reaction away from the evaporator region of the column.

Process for thermally cracking carbamic acid esters

The invention relates to a method for the purification by distillation of p,p-bisphenol A from the melt. The p,p-bisphenol A melt thus obtained is highly heat-stable, stable in storage and colour-stable, is free from high-boiling components and no longer contains any surface-active or non-distillable metal, salt, acid or polymer components and no sulphur-containing components; o,p-BPA and phenol are removed and the low-boiling components are scarcely detectable.

Method for the preparation of ultra-pure bisphenol A and the use thereof

The preparation of dimethyl carbonate by reaction of methanol, carbon monoxide and oxygen in the presence of Cu compounds is carried out in distillation units and the water of reaction is removed at least partially from the stripping region or the bottom phase.

Process for preparing dimethyl carbonate

A method of controlling a heat exchanger wherein the enthalpy flow into the heat exchanger serves as a correcting variable. The robust and versatile control method is particularly suitable for use in endothermic reactions and for distillation.

Method of controlling heat exchangers using enthalpy flow as the

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

A process for preparing monochloropinacoline (1-chloro-3,3-dimethyl-butan-2-one) by contacting a stoichiometric excess of pinacoline with chlorine at a temperature of -20.degree. to +70.degree. C.

1-Chloro-3,3-dimethyl-butan-2-one

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Leverkusen, Germany

Heinrich Steude