Basf Aktiengesellschaft

Basf Se Corporation

Eckehard Danz

Gerd Krome

Franz Merger

Michael Hesse

Tom Witzel

Klaus Harth

Matthias Irgang

Detlef Kratz

Klaus Pandl

Ralf-Thomas Rahn

Martin Schmidt-Radde

Manfred Sauerwald

Friedrich Wirth

Erhard Stahnecker

Markus Hölzle

Johannes E Schmidt

Wolfgang Steiner

Ernest Miesen

Arnold Wittwer

Christian Kuhrs

Thomas Grassler

Peter R Laurer

Cristina Freire Erdbr&uuml;gger

Werner Hebgen

Reiner Geier

Luc Cordemans

Martin Bruderm&uuml;ller

Reinhard Seifert

Gerd Dumbgen

The present invention relates to a process for the catalytic preparation of melamine by decomposition of urea over particular solid catalysts using a main reactor and an after-reactor. A catalyst having a low Lewis acidity is used in the main reactor and a catalyst having an equal or preferably higher Lewis acidity is used in the after-reactor.

Two-stage reactor for the production of melamine

The claimed invention relates to a process for preparing an aqueous formaldehyde solution comprising absorbing a formaldehyde-loaded gas stream, in an absorption zone, in an aqueous solution comprising from 0.000% to 0.01% by weight of a Bronsted base, based on the formaldehyde absorbed. The produced aqueous formaldehyde solution comprises: a) from 10 to 75% by weight of formaldehyde, b) from 0 to 500 ppm by weight of tetroxane, c) from 50 to 400 ppm by weight of formic acid, based on the formaldehyde absorbed, and d) from 0.2 to 5.0% by weight of methanol, based on the formaldehyde absorbed.

Aqueous formaldehyde solutions with a low tetroxane content

Alcohols are prepared by the catalytic hydrogenation of the corresponding carbonyl compounds at elevated temperatures and at superatmospheric pressure in the liquid phase by a process in which the catalyst used contains copper on an SiO,-containing carrier in the presence or absence of one or more of the elements magnesium, barium, zinc and chromium.

Preparation of alcohols

A process for the preparation of vinyl chloride by vaporizing liquid 1,2-dichloroethane, thermally cracking the 1,2-dichloroethane and cooling the hot reaction mixture by means of cooled and condensed portions of the reaction mixture, wherein a defined amount of the 1,2-dichloroethane is taken off as liquid in or downstream of the vaporizer and mixed with a defined amount of the cooled liquid portion of the reaction mixture, the mixture is distilled and the constituents taken off the top of the distillation column are mixed with the liquid 1,2-dichloroethane upstream of the vaporizer while the constituents taken off the bottom of the distillation column are worked up by distillation.

Preparation of vinyl chloride by thermal cracking of 1,2-dichloroethane

A process for the continuous isolation of phthalic anhydride and maleic anhydride from the reaction gases obtained by catalytic oxidation of o-xylene or naphthalene with air, wherein the reaction gases are treated with a hydrocarbon of boiling range from 115.degree. to 175.degree. C. as the solvent in a column, and are then treated with an organic solvent of boiling range from 180.degree. to 290.degree. C. in a second column, the phthalic anhydride and maleic anhydride being isolated from the liquid bottom product of the first column.

Continuous isolation of phthalic anhydride and maleic anhydride from

Impurities are removed from vinyl chloride by passing it over finely divided calcium oxide.

Removal of impurities from vinyl chloride

A supported catalyst containing copper and alkali metals, wherein the content of copper is from 1.0 to 12% by weight, based on total catalyst and expressed as metal, and the total content of the alkali metals potassium, lithium and sodium is from 0.3 to 9% by weight, based on total catalyst. The novel catalyst is useful for the preparation of 1,2-dichloroethane by oxychlorination of ethylene.

Supported catalyst containing copper and alkali metals

Growing community of inventors

Ludwigshafen, Germany

Eckehard Danz