Bayer Aktiengesellschaft

Wilhelm Hagen

Karl-Friedrich Zenner

Helmut Klappert

Peter Fischer

Christian Konig

Hermann Dallmeyer

Dieter Becher

Alexander Mitrowsky

Eckhard Tiemann

Heinrich Lokum

Johannes Werneburg

Hans Czwalinna

Ove Nommensen

Walter Levin

A process for the purification of toluenediisocyanate by fractionating a crude distillation feed containing toluenediisocyante, an organic solvent and less than 2% by weight of phosgene in a heat integrated system having an upstream distillation column, an interchanger and a downstream distillation column which are connected in series. The vapor which is recovered from the upstream distillation column is used to reboil the bottoms product of the downstream distillation column or the feed to the downstream distillation column in the interchanger. The crude distillation feed comprising less than 2% by weight of phosgene is fractionated into three product fractions P1-P3 and optionally a fourth fraction P4. P1 is a noncondensible gas stream enriched with phosgene and/or low-boilers. P2 is a solvent-enriched product. P3 is a high boiler enriched bottoms product comprising toluenediisocyanate, and P4 is a toluenediisocyanate enriched stream lean in highboilers and reaction residues.

Process for the purification of mixtures of toluenediisocyanate

Carbon monoxide is produced in an improved process in a carbon-filled, water-cooled generator in the configuration of a truncated cone in the longitudinal section, by the gasification of said carbon with a mixed gas of oxygen and carbon dioxide, wherein the improvement comprises injecting the mixed gas into the generator through at least one downwardly-directed, coolable nozzle arranged in the generator sidewall and removing the carbon monoxide formed.

Process for the production of carbon monoxide

Solutions of phosgene, an organic solvent and nitrogen or oxygen compounds which have a higher boiling point than the solvent are evaporated in a vacuum which is produced by a liquid ring pump operated on a phosgene-containing solvent as working fluid, the used working fluid being subsequently returned to the process.

Evaporating solutions which contain phosgene in a vacuum liquid ring pump

A process for pre-phosgenating organic primary amines is provided wherein a phosgene solution and an amine solution are combined in the suction side of a multiple stage rotary pump.

Continuous prephosgenation process for the production of organic

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Leverkusen, Germany

Wilhelm Hagen